Section II Gardening for Wildlife This section provides a general introduction to ecological concepts, which will assist you in the process of creating your Schoolyard Habitats site and the use of the site for instruction. Also included is practical, easy-to-use information on the concept and practice of gardening for wildlife. Ecology 101 Introduction to Native Plants Habitat Basics Butterfly Gardening Restoration Projects Soil Composting Container Gardening
Transcript
Section II
Gardening forWildlifeThis section provides a general introduction toecological concepts, which will assist you in theprocess of creating your Schoolyard Habitats siteand the use of the site for instruction. Alsoincluded is practical, easy-to-use information onthe concept and practice of gardening for wildlife.
Ecology 101Introduction to Native PlantsHabitat BasicsButterfly GardeningRestoration ProjectsSoilCompostingContainer Gardening
| 19ECOLOGY 101
The survival of individual species of animals and plants relies on the health oftheir habitat. Today, more than 900 types of plants and animals in NorthAmerica have been designated as endangered. To prevent the extinction of thesespecies and to conserve the amazing diversity of living things on this continent,people must work together to protect and restore habitat for wildlife. SchoolyardHabitats projects provide the opportunity for students, teachers, and communityvolunteers to act as wildlife biologists and restoration ecologists as they work on asmall scale habitat project on their own schoolgrounds.
Every living species has specific habitat requirements.Habitat is the arrangement of living and non-living things which together supplyan organism’s basic requirements for life. These essential components includesources of food, water, cover, and safe places to raise young.
Each species’ habitat has a characteristic physical environment, including climate,and often a characteristic type of vegetation. Eastern temperate forests tend tohave cold winters and wet, hot summers. Broadleaf trees like oak and maple livewell in these conditions; Eastern forests are defined by the mix of oak, maple,birch, and other trees that grow there. These trees create a canopy that shades theforest floor and provides habitat for many creatures, such as gray squirrels, white-footed mice, white-tailed deer, blue jays, and more. Deserts, on the other hand,receive little rain throughout the year and can only support plants able to toleratedry conditions such as cacti and sagebrush, which in turn characterize the habitatfor many other plants and animals.
In forests and all other habitat types, plants and animals living there are adaptedto their environment (they have inherited characteristics that enable them tosurvive in that location). Most plants and animals have one kind of habitat thatsuits them best, although they may be able to survive in several others. Otherliving things can survive in only one kind of habitat.
Even when two organisms live in the same area, their needs and how they meetthese needs may be distinct, allowing them to share the same space withoutcompetition.Two birds, for instance, might live in the same tree but eatdifferent foods, have different predators and have different tolerances totemperature. The birds live in the same place, but do not fill the same role, or
niche. If organisms share the same niche, they may compete and limit thenumber of organisms that can live there. Competition, over a long
time, may lead to greater animal and plant diversity asorganisms carve out distinct niches.
Organisms of differentspecies can coexist in thesame type of habitat whilehaving separate niches.
One acre of prairie is home toplants like grasses and clovers; insects like beetles and
grasshoppers; and small mammals like deer mice andprairie dogs. Since each has its own niche—diet, foraging or
hunting habits, needs for shelter andplaces to raise young—many speciescan live there.
Scientists who study the interactionbetween an area’s physicalenvironment and living things arecalled ecologists (“eco” is derivedfrom the Greek “oikos” meaninghome). They divide their studies byscale, from smallest to largest. Thesmallest unit ecologists study is anindividual organism of one species,including its habitat and niche.Ecologists may also study apopulation of organisms of the samespecies. The populations of plants andanimals that live near each other in aparticular habitat make up the livingcommunity. An ecosystemencompasses all living thingsinteracting with one another and withthe non-living environment, includingair, water and soil.
North AmericanHabitats
Trace the 39th Parallel across a map ofthe United States. Traveling fromcoast to coast along this latitude, youwould pass through a surprisingvariety of North American habitats.The journey would lead you throughCalifornia’s chaparral and the sands ofthe Mojave Desert, on to theevergreen forests of the RockyMountains and the mid-westernprairies before finally arriving at thebroadleaf forests of the East Coast. Allof these ecosystems contain an arrayof habitats, which, in turn, support anincredible diversity of living things.
The 39th Parallel only provides aglimpse at the diversity ofhabitats found in NorthAmerica. North of that latitudelie the wet evergreen forests ofWashington and Oregon. Southare the deserts of Arizona andNew Mexico, the wetlands ofLouisiana, and the subtropical
marshes of Florida’s Everglades. Onthe western shore, rocky tide poolsmark the meeting of land and sea,while the East Coast boasts sandybeaches, salty estuaries, and barrierislands. Aquatic habitats are found inNorth American ecosystems,including open oceans, lakes, ponds,rivers, and wetlands. Although werarely think of urban areas as ‘wildplaces’, cities are ecosystems, too. Rareand delicate ecosystems maysometimes be found alongside anabandoned railroad track, under theroaring jet engines of an airport, andin between city blocks. In the city, apark may be a squirrel’s habitat, whereit finds acorns to eat, water to drink,and a hole in a tree to hide and raiseits young. Across town, a skyscrapermay provide a nesting place for aperegrine falcon, while the park mayprovide it with food and water.
What creates this diversity in habitats?The diversity results from uniquecombinations of the physicalenvironment and the livingcommunity. Physical factors play a keyrole, since the amount of rain,sunlight, temperatures, and the typeof soil largely determine the kinds ofplants that can survive in an area.These factors change from north tosouth and with the presence ofmountains or sea, among otherfeatures. In addition, all animalsdepend directly or indirectly oncertain plants for food and shelter, andthe presence or absence of these plants
influences an animal’s survival in agiven habitat. Plant and animalspecies also affect each other and thephysical environment. Decomposingleaves may change the chemistry ofsoil or water while a bee thatpollinates a flower helps the floweringplant to reproduce.
The PhysicalEnvironment
Species are adapted to live in a habitatwith a certain range of physical andchemical conditions. This includesweather (rainfall and temperature),soil (both the chemical nature and thesupply of air and water available toplant roots), exposure to sunlight (sunor shade), and the composition of air.Other parts of the non-livingenvironment are also important indetermining whether a plant oranimal can survive in a given habitat.These include: wind, salinity (theamount of salt in the soil or water),geologic forms (such as mountains orrivers, which influence weather, andcaves or rocks, which some animalsuse for shelter), fire and otherdisturbances, the amount of airdissolved in water (in aquatichabitats), and whether thesoil, water or air has beenpolluted by significant levelsof toxic substances.
Plants need sunlight, waterand carbon dioxide gas tosurvive in their habitats. In
addition, they require nutrientssuch as nitrogen andphosphorous to grow. Withoutsufficient amounts of these non-living factors, a plant wouldweaken and eventually die. Allhabitats must have both asuitable physical environmentand the organisms on whichanimals depend.
Many parts of the physicalenvironment can becomelimiting factors when in shortsupply or in excess. Within ahabitat, each species has factorsthat limit its growth orreproduction. In a desert the lack ofwater is a serious limiting factor toplant growth. Add water withirrigation, and plants grow morequickly. Stop irrigation, and growthreturns to normal. For a tree seedlingon the shaded forest floor, amount ofsunlight may be what most limits theseedling’s growth. Other examples oflimiting factors include temperature,supply of minerals in soil, land forterritory and the availability of foodand nutrients. Temperature and otherfactors become limiting to growthand/or reproduction when theyapproach the limits of what a livingthing can tolerate.
Food Chains andFood Webs
Within a habitat, most organismsdepend on other living things to meettheir needs for food and often forshelter. Taking in food is critical tosurvival. From food, living things getthe energy they need to go about thebusiness of being alive. Plants get theirenergy from the food they makethrough the process ofphotosynthesis, and animals get theirenergy by eating plants and otheranimals. The path through whichenergy and nutrients pass from oneliving thing to another is called a foodchain. All living things are part of at
least one food chain, which includesspecies that live in the same oroverlapping habitats.
Green plants represent the first step inmost food chains. Duringphotosynthesis, plants (and a fewtypes of bacteria) absorb energy fromsunlight and use that energy to turnwater and carbon dioxide gas intofood. Plants are considered producersin an ecosystem because they producethe food that supports other livingthings in a food chain. All animalsrely, either directly or indirectly, onplants for food.
Animals that eat primarily plants arecalled herbivores, or primaryconsumers, and represent the nextlink in the food chain. Animals calledcarnivores, or secondary consumers,eat herbivores and form the next levelof the food chain. Some animals eatboth plants and animals and are calledomnivores. Many food chains endwith a tertiary consumer, or a toppredator, which eats secondaryconsumers.
Few food chains contain more thansix species, since a large percentage ofenergy is lost at each transfer fromeaten to eater. For example, a rabbitfeeds on grass for energy and thenspends most of this energy digesting,moving and controlling its bodytemperature. The fox that eats the
rabbit gets only a small fraction(about 10 percent) of theoriginal energy stored in thegrass. Because relatively littleenergy is passed from one link inthe food chain to the next, foodchains aren’t usually that long.
Energy loss also explains whythose at the top of the foodchain, top predators, are rare.Top predators like wolves andsharks must eat many smalleranimals to get enough energy,and so a large population ofwolves would not be able to findenough food. A food chain
pyramid shows how the population ofeach species in a food chain decreasesfurther up the chain. Primaryconsumers are much more commonthan secondary consumers, which arein turn more common than tertiaryconsumers.
Organisms are rarely part of just onefood chain. A collection of foodchains in a community form a livingnetwork called a food web.Decomposers are a part of all foodwebs and include microbes, fungi,insects, and animals that break downdead plants and animals, returningessential nutrients to the soil. Thisprocess ensures that nutrients areavailable again for use by plants andmicrobes.
Beyond providing food-energy for thepredator, predator-prey relationshipshelp keep populations of both speciesin check. When a predator isremoved, prey populations may growout of control, beyond the ability ofthe habitat to support them. Forexample, in Arizona in the early1900s, hunters killed huge numbers ofwolves, mountain lions, and coyotes;all of these were top predators in thearea of mule deer. With the decline ofpredators, the mule deer populationgrew from 4,000 individuals in 1907to more than 100,000 in 1924. Thehuge population of deer stripped theirhabitat of all the leaves, plants andother greenery they used as food.With food scarce, many deer starvedand fewer were able to reproduce. By1939, the deer population haddeclined to just 10,000 individuals.
Other Interactions
Food webs aren’t the onlykind of interactionbetween living things in ahabitat. Although you maynot think about it, eachtime you seek shade underthe boughs of a tree, youinteract with the tree.Plants and animals in acommunity depend on each
other to meet needs other than food,such as shelter, places to raise young,pollination, and the distribution ofseeds.
For an example of these other kinds ofrelationships, just look a saguarocactus. In the desert, mice and rabbitshelp disperse the seeds of the saguarocactus to new locations. During itsfirst years of life, a saguaro cactusneeds shaded habitat. To meet thisneed, the cactus depends on otherplants, such as a mesquite tree, toprotect it from the hot sun while theroot system develops. Later in life, thecactus provides shelter (and food) tomany other organisms. Gilawoodpeckers build nests in it; oncevacated, the nest may provide a homefor elf owls, lizards, insects, or spiders.
Like the saguaro cactus in the SonoranDesert, prairie dogs are importantspecies in their short grass prairieecosystem. They live in ‘towns’ madeup of hundreds of undergroundburrows and tunnels in the grasslandsof the American Midwest. Burrowsare built with chambers set aside for
sleeping and storing food.Abandoned burrowsprovide shelter formany other prairiecritters, includingprairie rattlesnakes,black-footed ferrets,and burrowing owls.
Life Cycles andHabitat
Butterflies look drastically different asadults than they did when they wereyoung caterpillars. The types of food,water and cover they require alsochange. Many organisms havedifferent needs as they go through thestages of their life cycle, especiallyorganisms like butterflies that undergometamorphosis. In these cases, the liferequirements of the young, or larvalstage, of a species can be extremelydifferent from the needs of an adult.In this way, some species may havemore diverse needs within theirhabitat than others.
Specialists andGeneralists
Scientists consider the members of aspecies generalists if they can live in awide range of habitat types and eat awide variety of foods. Specialists, onthe other hand, include species thatlive in a narrow niche and can liveonly in one or very few types ofhabitats. Relatively, generalists arebetter able to adjust to changes in theenvironment by finding a new sourceof food or cover. Populations ofspecialists grow when the resourcesthey rely on are available, but may notbe able to survive if changes threatenstheir only food, cover or nestingresource.
What is the quintessential generalist?The raccoon! They are generalistsfound in many different habitats.Raccoons live in habitats as diverse aswoodland, grassland, wetland, desert,and seashore, not to mention thealleys of inner cities and suburbanlanes. They live throughout NorthAmerica—from Canada to Panama.What are their secrets for success? Forone, they eat a varied diet, and canfind nutrition from many differentsources. Raccoon diets include plants,nuts, fish, rodents ,or the leftovers
found in garbage cans. This flexibilitymeans that if one source of fooddisappears, raccoons are still able tofind another. For cover, they do nothave specific needs. Any hole orcrevice will do. Raccoons have beenknown to make hideouts in pipes, treeholes and small rock hollows.
By contrast, monarch caterpillarsdepend on a single group of plants—the milkweeds—for food. Thesecaterpillars have evolved the ability toeat this plant that most other insectsfind poisonous. As a result, thereexists less competition for milkweedleaves. But this same specializationmakes monarchs vulnerable. Ifmilkweed disappears from one area,monarchs may have to move to a newhabitat. If anything threatens theplant over a larger area, or if thebutterfly is forced into habitat wheremilkweed cannot grow, the butterflypopulation will be threatened.
Adaptations
An adaptation is an inherited traitthat helps an animal or plant survivein its habitat.
Diet, behavior, physical anatomy andeven physiology (internalmechanisms), are ways animals adaptto their surroundings. Many livingthings have evolved unique ways ofdealing with the problems of survival.An animal’s adaptations—such as aneagle’s keen sense of sight or ahummingbird’s long beak—developover a very long time and can bepassed on to offspring.
Animals have adaptedto even the harshestenvironments. Someaquatic insects haveevolved a way tosurvive extremelycold temperatures.They can freeze whileremaining alive. Whenthe air warms up, these
insects thaw and return to normalshape and activity. Similarly, plantsand animals who call the desert homehave adapted over thousands of yearsto life in a place that gets fewer than10 inches of rainfall each year. Theseadaptations allow organisms like thekangaroo rat (which gets all the waterit needs from plants it eats) and thesaguaro cactus (which stores enoughwater to survive years) to thrive in thedesert environment.
But adaptations are useful only in thehabitat for which an animal isadapted. A freshwater newt, adaptedto living in or near water, wouldn’tsurvive long in the desert.
People often confuse adaptationwith adjusting or respondingto a change in environment.Adjustment happens, forexample, wheneverhumans climb to highaltitudes. On top of a15,000-foot mountain, itfeels colder and there isless oxygen to breathe.Humans adjust through
behaviors such as wearing warmclothes and staying inside a tent.Within a short time period, humansgo through a reversible physiologicalchange, which allows them to breathein a low-oxygen environment. Onceclimbers return to sea level, theyreturn to normal. This is a temporarychange that is not passed on tochildren. Adaptations occur over longperiods of time and are passed onfrom one generation to the next.
Limiting Factors
Just as some species require specificspatial requirements to meet theirneeds, other species have very specificfood or cover requirements. If one ofthese critical elements or factors ismissing a species cannot survive.These most specific habitat needs arecalled limiting factors because theirabsence limits whether a species canlive.
For example, many decades ago theNorth American wood duck wasdisappearing. Scientists had todetermine why this species wasdeclining alongside other flourishingduck species. The answer was simpleonce the situation was examined bylooking at the habitat requirementsfor wood ducks. Wood ducks requiresnags (old dead trees) with holes inthem to raise their young. Woodducks were loosing their habitatsbecause wetlands with old dead treeswere being destroyed fordevelopment. Resource agency andconservation organizations workedtogether to restore the habitat byplacing wood duck boxes on posts orin living trees near wetlands. Thewood duck boxes simulate the holes intrees wood duck require to raise itsyoung. Thanks to the placement ofwood duck boxes the species isthriving and its habitat restored. Theloss of suitable places to raise youngwas the limiting factor for the woodduck.
Animals differ in the size of habitatthey require. In general, large animalsneed more food-energy to survive andso need to hunt or forage within alarger area than does a small animal.For the larvae of the longhorn beetle,a small area inside a single oak treemay be sufficient. Beetle larvae livebelow the tree’s bark, creating tunnelsas they feed on wood and hide fromhungry predators. A squirrel mightfind cover in the same oak, but itshabitat, which includes its entireforaging range, stretches over 3 to 4acres. One kind of warbler bird mayrequire up to 7,000 acres of foresthabitat for a breeding pair, while ablack bear needs as much as 40,000acres for its home range.
Other factors influence habitat size.An organism’s feeding habits,mobility, nesting preferences, andterritoriality can all play a role indetermining its required habitat size.A bee, which has the mobility of flightand needs to find food with a highsugar content, has a much largerhabitat than an ant. Plant-eatinggrazers like buffalo need only aquarter the habitat that carnivoressuch as wolves require. Leaves andgrass are relatively common and easyto find for buffalo. By contrast, preyanimals are much harder to find thangrass, so their predators need to searcha larger area to find them.
Biodiversity andEndangered Species
Today, habitat loss is the leadingthreat facing wilderness, wildlife andbiodiversity in North America. Theterm ‘biodiversity’ refers to thevariety of species of plants andanimals in a given area. One way tomeasure the biodiversity of a givenarea is to count the number of typesof species living within that area.
Biological diversity has beenrecognized as an important measure ofan ecosystem’s health. All members offood webs, including humans, rely onhealthy ecosystems to provide foodand materials needed to live. Themore diverse an ecosystem, the greaterchance that some species will be ableto survive sudden disturbances in thesystem caused by climactic change,human impacts or the loss of a keyspecies.
Tropical rainforests face the greatestthreats to declines in biodiversity, butmuch of North America has alsosuffered serious declines. In 1973,concern over the loss of wildlife led tothe creation of the U.S. EndangeredSpecies Act, which aims to protect therarest species from extinction. To date,over 1,100 plants and animals in theUnited States are rare enough thatthey have been listed on the federalendangered and threatened specieslist. An endangered animal or planthas so few individuals left that it has
been officiallyidentified as closeto extinction.Threatened speciesare not in suchdire situations buthave suffered rapiddeclines in theirpopulations. TheEndangeredSpecies Actprovides for active
conservation and management ofthese species.
The sheer number of endangered,threatened and vulnerable species,along with high costs involved in theirprotection, has made conserving thesespecies a challenging task. Morerecently, conservationists and federalmanagers have shifted their focusfrom individual species to the habitatsof endangered and threatened species.Focusing on critical habitats, home toa diverse group of plants and animals,seems the most effective method tosave wildlife. In saving the habitat ofan endangered species, managers willalso be able to save the many uniqueorganisms that share that habitat.
Habitat Loss
In some cases, human alteration of theenvironment can endanger plants andanimals in a given area. For example,scientists linked the seaside sparrow’sextinction in 1987 directly to the lossand fragmentation of its habitat. In alittle over two centuries, vast portionsof the North American landscape havebeen altered by human activities,including development of housing,roads and cities, farming, resourceextraction, pollution, and hunting.Noteworthy examples include:
Prairies once covered 40% of thelower 48 states. Much of thisMid-Western grassland habitathas been lost to farming,development and overgrazing. Inaddition, periodic fires that
grasses depend upon have longbeen suppressed, allowing otherspecies to flourish. Wild grazerslike bison, which also played animportant role in the grassecosystem, were over-hunted longago. Scientists estimate that 99%of tall grass prairies, which oncestretched over 90 million acres onthe Eastern edge of the prairiestates, have been lost todevelopment and farming. Prairieloss has led to steep declines inmany species’ populations,including black-tailed prairie dogsand the now very rare black-footed ferrets.More than 90% of old-growthforests of the Pacific Northwesthave been disturbed bydevelopment and logging. Manyspecies, such as the endangerednorthern spotted owl, need amature forest habitat to survive.
Over 50% of wetlands in thelower 48 states have been cleared,drained, filled, or destroyed.Many of those remaining faceproblems with inadequate watersupplies (due to upstream damsand diversions), polluted run-offfrom agriculture and industry,and continued pressure fordevelopment. In California, only10% of original wetlands remain,most lost to agriculture anddevelopment. Especially notablehas been the shrinking ofwetlands in Florida, where theEverglades once reached fromabove Orlando to the state’ssouthern tip. The loss in wetlands
there has contributed to a 90%drop in the number of waterfowlin the area. A full one-third ofendangered plant species grows inwetland habitats throughout theU.S.Although beginning to recover,more than 80% of New Englandforests were cut when Europeanssettled the region and the landwas converted to farmland. Asagriculture has moved to the mid-west, Eastern forests are slowly re-establishing themselves. Acid rain,a by-product of modern industrialemissions, still poses a threat tothe health of these ecosystems.The Southeastern United Stateswas once covered in longleaf pineforests, which stretched fromVirginia to Texas. Only about 3%of these historical ecosystems stillexist, resulting in endangermentof birds like the red-cockadedwoodpecker. The rest has longsince been converted to cities,farms and tree plantations or haslost key habitat features due tologging, fire suppression and useof adjacent lands.Riparian ecosystems face thegreatest threats from dams,diversion of water, and pollution.Most major rivers in NorthAmerica are dammed to provideenergy, control flooding, anddivert water for irrigation andother uses. Inadequate river waterthreatens wildlife that needsflowing or deep water.
Human Impacts
As human populations continue togrow, more and more natural areas aredeveloped or converted to cropland tomeet increasing human demands forhousing and food.
Development—the building of newhouses, streets, highways, offices,schools, shopping centers and parks,and the clearing of land oftenassociated with new construction—isa leading cause of habitat loss.Building on wild land can destroy orseriously degrade wildlife habitat. Theextraction of natural resources fromcertain areas can impact habitatquality and species viability as well.
Conversion of wild habitat intofarmland increases with our need togrow food for greater numbers ofpeople. It also drastically changes thehabitat. While some organisms, likemigratory cranes on the Platte Riverwho feed on waste corn from theyear’s harvest, can live with farms,others, such as many of the nativegrasses of the prairie, cannot.
Run-off from farms, such as fertilizersand pesticides, can create problems indownstream habitats. If too muchfertilizer washes into a pond, forexample, the amount of availablenitrogen and phosphate cancompletely alter the physicalenvironment of the lake, creating hugealgae blooms, which deplete oxygenand seriously harm or even kill otherwildlife living there.
Pesticides also harm birds, butterfliesand other insects. Birds of prey, forexample, suffer enormously frompesticides even though they may notconsume them directly. Each animalthey consume may have a smallamount of the toxic substance in itsbody, and these amounts canaccumulate in the bird’s body overtime.
To protect wildlife, we need to betterbalance human needs withconservation and restoration ofhabitats. Sometimes, unexpectedconsequences of human activity harma habitat. For example, pollution(such as fertilizer in a lake or toxiclevels of chemicals) may render ahabitat unsuitable for life.
Natural Impacts onHabitats
Catastrophic natural events can alsospell disaster for habitats over theshort-term. But even after a severeflood or fire, most ecosystems canrecover. In most cases, the habitatdevelops back into a healthycommunity similar to the pre-fire orflood habitat over time.
Other powerful natural impacts cancome from disease, extremes inweather and climate change. Disease
can destroy a population of onespecies, which may impact the lives ofothers. Some 250,000 ducks on GreatSalt Lake appeared to have died frombotulism, a bacterial disease, in 1932.While the local population of duckswas decimated, ducks from other areaseventually moved in and repopulatedthe Lake. Even extremes in weather(an especially cold winter or longdrought) may become lethal to many.Hurricane Hugo destroyed manyolder longleaf pine trees thatendangered red-cockadedwoodpeckers rely on for cover.
Some habitats, such as mid-westernprairies or longleaf pine forests of thesouth, actually rely on periodic naturaldisturbances, such as fire, to stayhealthy. Yellowstone National Park is agood example of such an ecosystemand a place where fires have long beensuppressed to protect property andpeople in the area. When largewilderness fires erupted in
Yellowstone, the burning did causesome tragic losses of wildlife and parkfacilities. But within a few short years,the many benefits of a natural fire(often started by lightning) becameapparent. The park experienced anecological re-birth, with greater plantand tree diversity, leading to greateranimal diversity and a healthy, stableecosystem.
While most ecosystems have theresiliency to bounce back after a severenatural event, some changes may betoo great. Climate change, asevidenced in ice ages that regularlyoccur on Earth, may permanentlyalter the group of species able to growin a habitat. Human activity also maychange ecosystems irreversibly. Forexample, when a new species isintroduced to a habitat, the entirestructure of the place may change,never to return to its original state.
Some species are intentionally oraccidentally introduced into a non-native habitat from elsewhere. Theimpacts of particularly aggressivespecies can be enormous, altering theentire structure of an area orecosystem.
For example, the nutria, a smallbeaver-like mammal, was importedfrom South America and released intothe wild in a number of habitatsearlier this century. Fur farmerswanted them for their pelts. They arenow found in 15 states and havecaused much habitat havoc. InLouisiana, 20 animals were released in1938. There are now 20 million livingin the bayous and wetlands of thatstate. Their voracious appetite forwetland plants, added to theirconstant digging, has resulted in100,000 acres of marsh turned intoopen water, destroying the winterhabitat of waterfowl. Aside fromalligators in the southeast, there are nonatural predators to keep nutria incheck.
The weedy and shade-loving Englishivy plant is another example of a non-native species that has caused manyproblems for habitats it invades. Theivy is native to Europe and Asia andwas introduced into landscaping andgardens by some of America’s early
colonists. It has escaped from gardensinto many forests, where it createsdense cover on the forest floor andlowers plant diversity in the forest.Little sunlight reaches below ivy andthe shade stops native wildflowers,trees and shrubs from sprouting andgrowing. These native plants are theones wildlife rely on for food, coverand places to raise young. No animalsappear to use ivy to meet their needs,save the European starling, anotherintroduced, non-native species.
Habitat Fragmentation
Habitats are increasingly divided intosmaller and smaller areas because ofdevelopment or other land uses, suchas roads, housing, parking lots, andlawns, until many islands ofunconnected fragments remain.Habitat fragmentation can lead tohuge losses of wildlife because itaffects overall habitat size, createsmore edges, and isolates species fromother members of their population.
Some habitat fragments are just toosmall to provide for all the needs of aspecies. A black bear that needs40,000 acres of forest habitat tosurvive, will not survive in a 2,000acre fragment. Even for species with asmaller habitat range, the fragmentmay be too small to support enough
individuals for a healthy breedingpopulation.
Carving up a habitat creates moreedges and changes the qualities of ahabitat. Many bird species, forinstance, live in the interior of a forestand have a hard time thriving alongedges, where they are more vulnerableto attacks by predators. Physicalfactors along edges differ too—without the shade of the forestcanopy, more sunlight reaches theground and allows a thick understoryto grow. Some birds need a relativelysparse area of forest floor tosuccessfully forage for food.
Fragmentation also isolatespopulations or individuals by creatingbarriers to movement. Without forestcover, it may be harder for young todisperse to new areas. New individualsfrom other populations may no longerbe able to reach those living in thehabitat fragment, meaning that thegenetic diversity of the populationmay decline. Studies show thatdecreases in the size of the habitatfragments directly correlate withdeclines in species diversity.
The Good NewsMany conservation efforts have been successful in managing wildlife species and insetting aside larger tracts of wilderness so that wildlife can continue to thrive inthese areas. Many people are beginning to make wiser decisions about the ways inwhich land is developed and are joining in efforts to restore local habitat. It is evenpossible to restore degraded habitats. Many schools across the country are makingtheir contribution through Schoolyard Habitats projects. From Florida to Alaska,schools are creating wildlife habitat and restoring wetlands, prairies and forests ontheir schoolyards. Schools are engaging in Schoolyard Habitats projects to restorebiological diversity in their communities by removing invasive exotics and plantingnative species. They are providing much needed temporary habitat for migratorybirds and butterflies on long journeys, and year-round habitat for numerous localresidents. The work of schools is helping to open the eyes of the larger community tothe important issue of habitat loss, and showing communities that by workingtogether, we can make a difference.
A native plant is a species that naturally occurs on a site and has not beenintroduced from another region or country. Native plants thrive in their naturalsetting without disrupting natural ecological processes because they are perfectlyadapted to the conditions of that locale. Native plants provide the best diversity ofhabitat elements for wildlife. Wildlife species have evolved to rely upon nativeplants as food, cover, and sometimes even for water. The National WildlifeFederation strongly encourages the use of native plant species in all newplantings.
By choosing native plants for your Schoolyard Habitats site, youwill:
provide the best overall food sources for wildliferequire less water and overall maintenanceprovide excellent support to local wildlife specieshelp maintain the diversity of plant species in our communities
The wildlife in our communities flourish amid locally native plants. However,there are hundreds of species of exotic plants available for sale, which areoriginally from Asia, Europe, Africa, or Australia and now call the landscapes ofNorth America home. These plants do not sustain local wildlife as well as nativeplants do. Though these plants may offer birds fruit, squirrels nuts, andhummingbirds and butterflies nectar, they do not provide the full range ofseasonal habitat benefits that appropriate locally native species provide. If wewant to attract wildlife and to restore the critical, often unseen small pieces inour ecosystems, we need to bring back locally native plants.
An equally important reason to use locally native plants is to reducethe possibility that exotic plants from our landscapes will run wild.Native plants do not become invasive; that is, they will notreproduce rampantly, invading and impoverishing thediversity of our remaining natural habitats (as an increasingnumber of exotic plants now do). Non-native plantsoften reproduce quickly, depleting the diversity ofremaining natural habitats. When a non-nativespecies is planted in a new place, it is isolatedfrom its original region or country andthe controls present there: insects anddiseases that limited its spread inits place of origin. This lack ofcontrols in a new area oftenallows the plant species to spreadunchecked in its newenvironment.
Rapidly growing and reproducingexotics often displace native plantsthat cannot compete with them.Consequently, animals that dependon native plants to provide a
particular habitat componentmay not find a suitablereplacement among the non-native species. Exotic plantsthat have been popular informal landscaping but whichhave been particularly invasivein many parts of the U.S. (andtherefore should not beplanted) include: purpleloosestrife, multiflora andCherokee roses, Asiatic bushhoneysuckle, Japanese honeysuckle,nandina, privet, autumn and Russianolive, and burning bush euonymus,among many others. NWF and yourlocal native plant societies can provideregion-specific plant lists to assist withyour plant selections.
Locally native plant species meetvirtually any landscaping need. Bychoosing native species, you willreplace the monotony of the fewexotics that so dominate ourlandscapes and the spread of exoticinvasives which are choking out thediversity of local plants in woodlands,roadsides, meadows, and naturalecosystems.
Our landscapes, carefully planted withlocally native species, can be effectiveinstruments in restoring native plantsto our communities and open spaces.
Most local nurseries andplant centers sell native plants,whether they know it or not. Sincesome nursery staff may not be familiarwith native plants and their benefits,educating yourself about the plantsyou would like to purchase prior tovisiting the nursery is helpful. Manynurseries are willing to special-orderplants that they do not normallystock. If possible, request your plantsby species name rather than commonname, as one common name is oftenascribed to many different species.The best sources of finding reputablenative plant suppliers are your statenative plant or wildflower society.
All wildlife needs an appropriate combination of food, water, cover, and places toraise young. Therefore Schoolyard Habitats sites must include these four essentialhabitat elements specific to the local wildlife they seek to support and attract.Some areas of the schoolyard might already be visited by wildlife; these areas maynaturally provide some or all essential habitat elements. If so, consider enhancingor restoring habitat that already exists. It is just as important to restore andconserve existing habitat areas as it is to create new habitat on the schoolyard.
Providing a wide variety of appropriate habitat elements will attract a diversity ofwildlife to your schoolyard. After learning about habitat basics, use the SiteInventory activity to evaluate your schoolyard and determine how it can beenhanced to better support local wildlife.
Following are a few brief suggestions on how to provide food, water, cover andplaces for wildlife to raise young on your schoolgrounds. Accompanying eachhabitat component is a preview of the corresponding portion of the SchoolyardHabitats Application which your school will eventually be completing.
Food
The ideal Schoolyard Habitats plan uses vegetation to supply as much food aspossible to meet the year-round needs of many local species. Shrubs, trees, andother plants produce foods, such as acorns, nuts, berries, and other seeds. Leaves,buds, catkins, nectar, and pollen are also important food sources.
Locally native plants are the basis for thenatural food chain in any given ecosystem.Therefore, it is important that any SchoolyardHabitats plantings consist of locally nativeplant species that include trees, shrubs,perennials, and annuals. Contact a CooperativeExtension office, local garden center, state non-game wildlife program, nature center, or theNational Wildlife Federation field office closestto you for recommendations about the bestlocally native wildlife plants.
While plants are maturing, and in areas withcold winters, natural food sources can besupplemented with food for birds. The bestfoods for feeders are sunflower, safflower, prosomillet seed, niger seed, and suet. In warmmonths, sugar water in regularly cleanedhumming bird feeders supplements the nectarand insects that flowers provide. Feedermaintenance is an excellent ongoing studentproject.
Throughout the year, wildlife needswater for drinking, bathing, and insome cases, breeding. Water can besupplied in a birdbath or othershallow dish, a small pond, a shallowwetland, or stream. While vegetationholds droplets from rain or morningdew, a more constant, reliable sourceof water is needed by many wildlifespecies and therefore is recommendedin Schoolyard Habitats sites.
Butterflies, birds, frogs, and toadsoften prefer to use shallow, puddle-like water sources. Create puddles byfilling a shallow basin with clean sand;sink the basin into the ground in asunny spot within your garden. Keepit flooded so that some of the waterand sand spill over the edge atdifferent times of the season.
An elevated birdbath may protectbirds from cats and other predators,and can be an attractive addition toyour Schoolyard Habitats site. Placebirdbaths near an overhanging branchor a nearby bush to provide a quickescape route for songbirds frompredators but not so close thatpredators have a good hiding placewithin pouncing range. The bath
Basic Steps for Building a Pond:1. Check Local Regulations.Many schools are concerned with theliability issues of having open water on their campuses. Beforeplanning pond construction, check school district and municipalityguidelines. These are usually easy-to-follow regulations regardingthe size, depth, and location of schoolyard water features.
2. Observe the natural flow of water on the property. The best timeto do this is right after it rains. The ideal site for the pond may bewhere water naturally accumulates on the schoolyard. Make surethat the site does not receive excess nutrients from compost piles,fertilizers placed on lawns, or street runoff.
3. Choose Pond Structure. One of several options available forcreating pond structures is to use a commercially available flexibleliner. Create a basin by excavating the soil and providing agradually sloping beach area so that amphibians and other wildlifespecies can leave and enter the pond easily. Many schools chooseto provide an overflow “wetland” area next to the pond (a place forwater to flow during excessive precipitation), to support additionaltypes of plants and wildlife, and to thereby provide greatereducational opportunities.
4. Install. Before laying the liner, pad the hole with a layer of sand orsome old carpeting, and then put the liner in place. Secure withrocks. Before filling pond with water, check to see if the localmunicipality uses chlorine or chloramine. Chlorine will dissipateafter one week, but a neutralizer is necessary in order to adjustchloramine levels.
5. Add Water and Vegetation. Cover the surface of your pond with alayer of leaves. These will sink to the bottom and form an organiclayer and provide habitat for microorganisms. Place plenty ofplants, rocks and tree branches in the pond as emergent structuresso wildlife have places to sun and to seek cover. A good way tomimic nature’s recipe for a healthy pond is to add a bucket of waterfrom a nearby natural pond. Do not stock the pond with fish.Wildlife will eventually find the pond on their own. If aquatic plantsare added, be sure to add only native species—these will offer themaximum benefits to local wildlife. Avoid exotic ornamentals.
6. Take Safety Precautions. Address safety concerns by educatingstudents about potential risks. Student-made educational signsposted close to the pond are a great way to call attention to thepresence of water. Another way to slow foot traffic and create aboundary between the pond and a playground area, for instance, isto install low fences or benches around the pond. Small ponds mayalso be created in courtyards where students are always visible.Another solution is to create a deep basin, and back-fill much of thebasin with large rocks. This type of pond will support small aquaticspecies while remaining quite shallow (which will allay fears ofpotential danger to students).
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should be no deeper than 3” and havegently sloping sides, with water lessthan 2” deep. In summer heat, be sureto replace water regularly and to keepbirdbaths clean. In winter, iftemperatures drop well below freezing,use a birdbath heater or remove ice inthe morning and refill with waterdaily.
If a creek, stream, pond or wetlandalready exists on the schoolyard,consider enhancing or restoring thatarea. If a water body is not present,many schools choose to create a pondas part of their Schoolyard Habitatsproject. Ponds not only help support agreater diversity of wildlife, butexpand opportunities for hands-onteaching and learning. Students withschoolyard ponds learn directly abouteverything from aquatic insects towater quality to physical science. Asmall pond built into the ground canprovide water for drinking andbathing as well as cover andreproductive areas for small fish,amphibians, insects, and reptiles.Many birds and amphibians rely oninsects that spend part or all of theirlife in the water. Observing naturallyoccurring local ponds will helpstudents learn about the characteristicsand life requirements of locally nativeaquatic plants and animals.
Some people are hesitant aboutcreating a pond because they associateponds with mosquitoes. Though somemay see them as a nuisance,mosquitoes do help support manynatural predators such as bats anddragonflies. In healthy ecosystemswith plenty of native vegetation,mosquitoes usually do not pose anyproblems. If mosquito larvae are aconcern, eliminate standing water byinstalling a small circulating pump.
Many certified National WildlifeFederation Schoolyard Habitats siteshave installed ponds on theirschoolgrounds. Whether they haveremoved a concrete courtyard, or
simply converted an unused corner ofgrassy lawn, they are all now enjoyingthe wildlife that visit and make theirhomes in these ponds, and theinstructional possibilities the pondprovides.
Cover
Wildlife needs protective cover fromheat, cold, wind, rain, and predators.Many plants that offer food can alsoprovide valuable escape cover forwildlife. Densely branched shrubs,evergreens, grasses, as well as hollowtrees—upright and fallen—rock piles, brush piles, andstone walls can all providecover for many animalspecies.
The ideal wildlife habitatarea includes plantsranging in size anddensity from low groundcover to tall, maturetrees. Arranging plants ingroups that mimic thegrowth of plantcommunities (rather than
in isolated islands) will increase theamount of cover provided. Increasingthe diversity of plant species willincrease the diversity of wildlife that issupported; this variety of plant lifeprovides birds and other animals witha wide array of appropriate cover forfeeding, hiding, courting, and nestingactivities.
To add to the types of cover on theschoolyard, students can constructand erect nesting boxes for theresident or migratory songbirds,ducks, and bats that live in the area(these structures are also availablecommercially). Each type of wildlifenesting box has specific requirements;it is important to identify the overallbox size, entrance size, design, andplacement needed in order tosuccessfully attract specific species.Following these specifications willboth ensure that the box is usable bythe intended species, and that the boxis not unduly vulnerable to thatspecies’ predators.
Resources for Nest Box Plansand Information:
The U.S. Fish and WildlifeService maintains an excellent listof how to attract and support 13bird species through nest boxes:http://migratorybirds.fws.gov/pamphlet/pamplets.htmlBat Conservation Internationalprovides detailed plans on itswebsite for constructing batboxes, bat conservation issues.Videos, books, and manyother resources can also beordered online:www.batcons.org
The NorthAmerican Bluebird Societyprovides thoroughinformation aboutbluebirds and supportinglocal populations throughbluebird boxes:www.nabluebirdsociety.org
To be complete, habitat areas mustinclude safe places in which wildlifecan raise their young. Examplesinclude appropriate areas for nesting,specific plants upon which butterflylarvae depend, and the security ofpond water for tadpoles.
Consider providing places to raiseyoung through both vegetation andhuman-made devices. Attachbirdhouses and nesting shelves toposts, trees, or buildings. Maintain asmany snags (dead, standing trees withhollow cavities) as possible. Plantdense pockets of shrubbery to providesafe areas for many species of wildlife.
Some of our most interesting animalsrequire a body of water as a safe havenfor their young. Many salamanders,frogs, toads, and insects, likedragonflies and water boatmen, beginlife in water and are unlikely toprosper on the schoolyard without thesafe, healthy water environments thata clean stream or small pond can offer.
Sustainable Gardening
A sustainable garden works inharmony with nature. In sustainablesystems, plants are grown withoutdepleting natural resources orcontributing to pollution. And, inorder for anything to be sustainable, it
should continue for a long time. Thismeans that it should sustain itself asmuch as possible, without constantinputs from you.
There are many techniques that canimprove the health of the garden andminimize any negative impact on theenvironment.
MulchingMulch helps keep water in the soiland available to the plant, rather thanevaporating into the air. This can helpreduce water consumption. Asmulch breaks down, it providesnutrients to the soil, which can helpreduce or eliminate the need foradditional fertilizers. Be sure to usemulches that are from sustainableforestry practices (not Cypress treemulch), and that are free from pestsand diseases. Your cooperativeextension office can help you findsources of mulch in your localcommunity.
Reducing Lawn AreasGrass lawns often require chemicalsand frequent maintenance. Gas-powered lawnmowers produce highamounts of greenhouse gases, whichcontribute to the air pollution thatcauses global warming. Since lawnsare often made of only a few types ofplants that most animals do notconsume, they do not provide a lot ofvalue for wildlife. Replacing grasslawn with nativewildflowers, bushes,and trees provides thefood, shelter, andcover that help tomaintain healthy,natural ecosystemsand reduces your timeand labor working onthe lawn!
XeriscapingXeriscaping is an approach tolandscaping that minimizes outdoorwater use while maintaining soilintegrity through the use of native,drought-tolerant plants. This is acommon practice in drier areas, suchas the West and Southwest, wherewater supplies and water quality are invery short supply.
Removing Invasives andRestoring Native PlantCommunitiesNative plants are better for theenvironment than exotic plants,generally requiring less fertilizer andother additives, less water, and lesseffort in pest control. They areespecially important to native wildlife,such as pollinators, that may havecoevolved with a particular species.Pollinators often rely on a certain typeof flower as a source of food, while theflower depends on the pollinator totransport its pollen to other flowersfor reproduction.
When non-native plants are used,they often times upset the delicatebalance of a local ecosystem andsometimes even out-compete nativespecies to the point of extinction.Wildlife benefit more when nativeplant communities remain intact, orare restored to their natural habitats,providing the best source of food forwildlife.
Once the habitat basics of food, water, cover, and places to raise young areunderstood, it becomes much easier to identify and provide for the needs of localwildlife. Engage students in learning about the specific needs of various localspecies. Because so many schools decide to attract and support butterflies as partof their Schoolyard Habitats project, following are suggestions for creatingbutterfly habitat.
A butterfly garden is a great addition to any habitat project, no matter how largeor small. Beyond the beauty butterflies bring to a schoolyard, they also play akey role in ecosystems by pollinating plants. Studying butterflies is an excellentway to teach concepts of life cycles, the importance of biodiversity, andinterdependence of species in a hands-on way. Butterfly gardens can be created ina small area; many schools plant butterfly gardens in courtyards or close towindows so that their activity can be easily observed. In order to attractbutterflies, your Schoolyard Habitats site will need to provide places for them tosun, sources of nectar, food sources for caterpillars, and access to water.
Butterflies are often found resting in sunny patches: they use the sun fororientation and to regulate body temperatures. Like all insects, butterflies areectothermic (they do not produce their own body heat). They fly best when theirbody temperature is between 85-100˚F. (Students may notice that butterflies arenot very active on cloudy days).
To provide sunning spots for butterflies, place large, flat stones in the schoolyard.If necessary, remove a little soil to stabilize the rock. Also make sure the selected
vegetation is planted in an area that receives sun for mostof the day.
Minerals are an essential part of male butterflies’ diet.These minerals are readily available dissolved in water,especially water existing in puddles. The large surfacearea-to-volume ratio of shallow water allows for greaterevaporation, which concentrates the dissolved minerals inthe remaining water. Butterflies do not need a largeamount of water; in fact they quickly expel most of thewater they uptake,primarily retaining dissolved minerals.
Students can make one or more butterfly puddles bycreating a small depression in the ground and allowingthem to fill with water. As part of ongoing sitemaintenance, students should check on the puddle duringdry periods, and spray periodically with a hose.
Another way to provide water is to dig a hole in theground to accommodate a container. Place the containerin the hole, level the ground to the top of the containerand fill with rocks and soil. Fill with water until the soilbecomes saturated and there is standing water at thesurface. Be sure to check for water periodically.
When selecting plants for a butterflygarden, be sure to choose locallynative plants that provide both nectarplants for the adult butterfly, and leafyhost plants for eggs and caterpillars.Overlap the blooming time of theflowering nectar plants; butterfliesrequire a nectar source throughouttheir adult lives. Be sure not to usechemical or biological pest controls onor around the plants in the butterflygarden, as these can be fatal tobutterflies and their larva. Plant thevegetation in a sunny spot that isprotected from the wind.
Butterflies visit and pollinatehundreds of flowers. Common nectarplants include: aster, joe-pye weeds,milkweeds, black-eyed susan, phlox,butterfly-weed, purple coneflower,sweet pepperbush, sunflowers,cardinal flower, goldenrod, and many,many more. Your local nursery ornative plant society will be able torecommend plants appropriate foryour region.
The chart below summarizes commonbutterflies that have rangesthroughout most of the U.S. and the
plants that are required for theirrespective caterpillars.
Many lessons can be learned fromobserving the life cycle and changes ofbutterflies. The importance ofbiodiversity is illustrated by differentplant requirements of the larva, andadult stages. The relationshipbetween plants and butterflies is agreat example of interdependence; theplants need butterflies for pollinationand butterflies need plants as foodsources and places to lay their eggs.
There are two formal internationalprograms that support butterflymonitoring by students; seeMonitoring Projects (p. __) for moreinformation.
Butterfly Caterpillar Food Source
American Painted Lady cudweeds, everlasts, antennariasCabbage White many plants in the mustard family
and nasturtiumClouded Sulphur cloversGray Hairstreak many pea and mallow familymembers; many othersMonarch milkweed family, esp. swamp
milkweed and butterflyweedMourning Cloak willows, American elm, quaking
aspen, paper birch, hackberryPainted Lady thistles, mallows, nievitas, yellow
fiddleneckPearl Crescent astersRed Admiral/ White Admiral wild cherries, black oaks, aspens,
yellow and black birchSpring Azure dogwoods, wild black cherry,
Many schools with larger amounts of land focus their Schoolyard Habitats effortson restoring local ecosystems and enhancing these areas. School communitiesacross the U.S. have joined together to restore prairies, wetlands and forests on oradjacent to school property.
Those with intact ecosystems on site can study these areas and identify ways inwhich these areas can be enhanced to improve the habitat value for local wildlife.As with all Schoolyard Habitats projects, tapping into community resources andexpertise is essential.
Restoration Projects
A Teacher’s Story: Engaging Iowa Youth in Schoolyard PrairieRestoration by Michael Blair
(Excerpted from Habitats Newsletter, NWF, Summer 2001)
In 1991, after working for four years in Honduras, I decided to return to Des Moinesto teach. I was assigned to a 7th grade science position at Hoyt Middle School.Drawing on my experiences in Central America, I expanded on the standard tropicalrainforest unit and engaged the students in fund-raising activities to buy acres ofrainforest. Around that time, I learned that 200 years ago, 85% of Iowa wascovered in prairie but that today, less than 1% of the original prairie is left. Itoccurred to me one day: What if someone in Brazil started buying up Iowafarmland and turning it into prairie? I created an open-ended lesson on the effectthis would have on Iowa. After the lesson, many students felt strongly that weneeded to take care of our environment before we started telling others what to dowith theirs.
Together, we decided that reconstructing aprairie was the best way to understandone; by doing so we would also be givingfuture students an outdoor laboratory. Forme, there is no other way to teach than tohave the students experience things firsthand and to make it relevant to them. I hadno prior experience with prairie restorationbut learned along with the students.
During the following year, my at-riskstudents in our School-Within-A-Schoolprogram researched prairie reconstructionmethods. One group studied the kinds ofplants that grew locally 200 years ago; asecond researched the best ways toprepare the land and to plant the seeds; andthe third group raised money and kept trackof the finances. The principal obtaineddonations and the teachers adapted theircurriculum to focus on the prairie acrossthe disciplines. Although I was transferred
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a year later, the teachers that followed me expandedthe prairie to three times its original size.
At my current school—Roosevelt High School—mystudents and I have established the 3,600- square-foot“Sunflower Prairie.” The students help to maintain theprairie and use it in the fall and spring for a variety ofactivities: biology classes can be found studying theplants and animals in the prairie, while English classesread prairie literature under the sunflowers.
The prairie projects have given me a greater awarenessof how much we have lost in Iowa over the years. Mystudents and I are learning new things virtually everyday. Through these projects, the students andcommunity have become aware that a prairie is notjust a weed patch but something of great value andbeauty. Former students continue to feel a sense ofstewardship; they tell me they stop by the prairies tosee how they are doing. One day, a year after I leftHoyt Middle School, I stopped by to see how theprairie was progressing. Before I got to the prairie, Isaw two little girls jump off their bicycles and run intothe prairie to play hide-and-seek. I knew from that pointon that this prairie would have the support of futuregenerations of students.
A Teacher's Story—continued from page 36
SOIL
Soil is the basic building block of any Schoolyard Habitats project, it is needed toprovide plant material with micronutrients, air, and water. Soil is composed ofliving and non-living material. It is about 25% water, 25% air, 45% mineral(rock particles), and 5% organic matter. Organic matter is made up of decayingplant and animal matter. Bacteria and fungi live in this orgainic matter andchange it; along with the minerals, air and water into forms that plants canreadily use to become healthy food and cover sources for wildlife.
Soil structureThe ideal soil for your project site is loam. It is dark in appearance, crumbly totouch, slightly moist. Loam contains less than 52% sand, between 28-50 % silt,and 7-27% clay.
All soil is composed of sand, silt, and clay. These distinctions are made byparticle size only, with sand being the largest and clay the smallest. The particlesize of soil components determines the soil structure, which affects how wellwater is retained, how much air is in the soil and how easily minerals are releasedfor uptake. Younger students can collect soil samples from the schoolyard, andcreate charts indicating what they find in their sample on close inspection (i.e.pine needles, rocks, worms, etc.). Basic information about soil structure can alsobe gained by conducting the Squeeze Test or Jar Test. (See boxes p. X)
pHMost plants thrive in soils with a pH between 6 and 7. The pH of the soilgreatly affects the activity of soil organisms and the availability of nutrients. Forexample, when the pH is lower than 6 some nutrients become less water soluble,therefore less available for uptake by plants.
Engage students in testing the pH of the soil. Prepare a soil slurry with somedistilled water and soil in a clean dish. It should have the consistency of thick
mud. Let the slurry stand for one hour. Then put a strip of litmus
Soil
Jar TestA test for determining soil composition is the glass jar test.Obtain one cup of soil; remove any pebbles, debris, leaves, orroots. Break up any lumps. Place the soil in a glass jar with atight fitting lid. Add 1-2 cups water. Shake the jar vigorouslyuntil the soil is suspended. After one minute measure theamount of soil that has settled with a ruler, this is the sandcontent. After one hour measure the amount of soil that hassettled, subtract the amount of sand. This is the silt content.24 hours later measure the total amount of soil settled, subtractthe amount of sand and silt. This is the clay content of the soil.Divide the depth of each layer by the total depth of the soil, andthen multiply by 100 to get percentages of soil components.Ex: .5"/3" x 100 = 16.6 % sand/silt/clay.
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paper in the slurry and leave it therefor one minute. Rinse off the paperand compare the changed color to thekit’s litmus chart to determine the pH.
NutrientsThe three nutrients that plants usemost are nitrogen (N), phosphorous(P), and potassium (K). Nitrogen isresponsible for leafy growth and thedark green color of leaves.Phosphorus encourages plant celldivision. It is necessary for flower andseed formation, helps roots grow, andprotects plants from disease.Potassium also encourages rootgrowth and protects against disease. Itis an important nutrient for theprocess of photosynthesis.
Micronutrients, while used in smallerquantities, are equally important tothe growth of healthy plants. Thereare 10 micronutrients that are deriveddirectly from minerals and decayingplant matter: calcium, magnesium,sulfur, iron, copper, manganese,boron, chlorine, zinc, andmolybdenum. Carbon, hydrogen andoxygen are essential for plant growth,but these nutrients are found in theair spaces in the soil structure, not thephysical soil itself.
Squeeze TestGrab a small handful of soil. Make a fist and release. If the soil falls apartand feels gritty, it is sand. Sandy soil has quick drainage and low nutrientlevels, requiring frequent watering and fertilization. If the soil has a slippery
texture and slides apart, it has a highpercentage of silt. Silty soil has poordrainage and moderate ability to retainnutrients. If the soil retains it shapeafter it is squeezed and is sticky whenwet it is mostly clay. Clay is rock-hardwhen dry; it can store nutrients, butroots and water have difficultypenetrating it. Loam is a mixture of all
three of these particles. It has a crumblytexture with some grittiness and some stickiness.
A great way to enhance the richness of soil and toadd nutrients and micronutrients is to apply compostat least once a year. Composting food scraps andyard waste also reduces the amount of solid wastegoing to landfills. An estimated 3/4 of solid wasteproduced in the U.S. is comprised of organic materialthat could easily be composted.
Composting will also save your school money thatmay otherwise be spent on fertilizers and soil.Composting can be a great illustration of conceptssuch as nutrient cycling and decomposition. For
information on constructing or purchasing a bin, see the Resource section at theend of this section.
Materials for composting are split intotwo groups: greens and browns. Greensare materials that are high in nitrogenand browns are high in carbon. An idealratio for an optimal compost pile is 30 partscarbon to one part nitrogen. The closer tothis ratio, the higher the temperature of the pile and themore quickly materials will decompose. This figure is based onweight, not volume. Generally, if you have equal amounts ofgreens and browns by volume, the pile should operate well. High nitrogenmaterials, such as fresh cut grass, should be used in a smaller ratio (40:60).
Shred coarse material before placing in the bin, this will increase the surface areaof the material and lead to quicker decomposition.
Some schools collect their “greens” (fruits and vegetables) in the school cafeteria,which both reduces the amount of school waste, and helps create more compost.After educating the school community about the purpose of composting, and
GREENS (nitrogen) BROWNS (carbon)
fruit strawvegetables fallen leaveshair clippings shredded newspapertea/ coffee grounds and filters dried pruningsfresh yard clippings corn stalks
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Materials that should not be composted
meat dairy productsoils (butter, mayonnaise) pine needlesbones dog or cat manurebarbecue ashes/coal forks, knives, etc.
exactly what can and cannot be addedto the compost, consider placing abucket with a tight fitting lid (picklebuckets work well) next to thetrashcans in the cafeteria to collectmelon rinds, vegetable scraps, etc.The contents of these buckets shouldbe added to the compost pile daily toavoid any unpleasant odors.
Locate the bin in a shady, well-drainedarea. The bin should either be placedon top of, or the bottom should bemade of wooden slats, leaving spacesfor air to flow through the pile. Themicro- and macro- organisms livingand working in the compost pile needair to survive and work efficiently.Allowing airflow will also reduceunpleasant odors, but take care not toleave holes that are large enough forrodents to get in. Some composters inurban areas use wire mesh to make orline compost bins to prevent rodentvisitors.
Begin the pile with a layer of brownsat the bottom; moisten this layer. Acompost pile should consistently be as“wet as a squeezed out sponge.” Adda green layer. Build as many layerspossible with your materials. Thelayers should be spread out well andnot too deep. Always make sure thetop layer is made of browns and that
it completely covers the lower layers.This will discourage odors and pests.Mix the pile thoroughly every week ortwo. The compost is ready for usewhen the materials have all broken-down into a crumbly soil texture.
Worm BinsVermiculture is both the art of wormcomposting and the resulting wormcastings, which are the best fertilizeravailable. Vermiculture is a popularway to compost in a school settingbecause it can be done inside incompact containers. It is also a greatway to demonstrate on a small scalehow to provide habitat for creatures.For a worm bin to work you will needto understand and provide the properfood, water, cover and places to raiseyoung that the worms andmicroorganisms require to survive inyour classroom.
To determine the size of the wormbin, survey the amount of food scrapsthat are normally generated. Forevery pound of food scraps generatedper week, one square foot of surfacearea should be provided. An averageestimate is two square feet of surfacearea per person. Binsshould be between10-18 inchesdeep with a
tight-fitting lid and holes in thebottom or side for ventilation. Keepthe holes 1/4” or smaller to keep bugsout. There are many low-cost, pre-made bins on the market (seeResources p. x).
Make a worm bed by placing 1” stripsof newspaper or shredded cardboardor peat moss in the bin, filling it 1/3to 3/4 of the way full. Moisten thebed and add a few handfuls of soil.
You will need to get some red wigglers(Eisenia fetida). Red wigglers are theworms that can often be found just atthe soil’s surface eating leaves ormanure. They are the best for wormbins because they can withstandwarmer temperatures than otherearthworms. These worms can beobtained from a bait shop, a friend’svermiculture bin, or by mail order.General guidelines are 1 pound ofworms to every 3.5 pounds of food.Place the worms in the bin and givethem about 1 pound of food scrapsinitially. Leave them alone for a fewweeks; allow them to get used to theirnew home. After the first few weeks,the worms should be able to handleabout 1 pound of food scraps persquare foot of surface area per week.Always bury fresh food scraps underthe bedding to eliminate fruit flyproblems.
Keep the bedding moist, but not wet.Apply the same rule as for othercompost piles—as wet as a squeezedout sponge. Place the bin where itwill not freeze or overheat.Temperatures over 84°F are fatal tored wigglers.
The kitchen scrapsthat are added to thebin will add moisture
as they decompose.Worm bins should be able to
absorb this excess moisture, butwhen using plastic or metal binsyou may have to add some morebedding material periodically toabsorb the water. If the bins are
located outside, holes can be drilled inthe bottom for drainage. The bin willgive off a mild odor if it is too wet.Adding shredded newspaper willeliminate this problem.
The worm bin should be harvested atleast once a year. It can be harvestedas quickly as 2-3 months after the binis set up. To harvest, simply reach inand scoop out the compost wormsand all. Sprinkle the compost around(but not covering) the base of plants,1/4" to 1" thick. Or blend thecompost into soil using no more than20% compost.
When adding new plants to theschoolyard, add compost orvermiculture to the habitat’s existingsoil; be sure to add less than one-halfthe volume of the existing soil. If youplace the “good” stuff only aroundnew plants the roots may refuse tospread into the pre-existing, untreatedsoil.
Suggested ResourcesAcorn Naturalists17821 East 17th Street, #130PO Box 2423Tustin, CA 92781-24231-800-422-8886www.acornnaturalists.com
Supplies many teaching toolsincluding worm bins and vermicultureand composting books.
Let’s Get Growing1900 Commercial WaySanta Cruz, CA 950651-800-408-1868www.letsgetgrowing.com
Supplies materials for composting, soilstudies, and general gardeningresources.
Mastercomposter.comOnline organization that serves as aclearinghouse for compostinginformation. Directory for localprograms, places to buy tools, bins,worms, and much more.www.mastercomposter.com
University of MissouriCooperative Extensionwww.muextension.missouri.edu/xplor/agguides/hort/g06956.htm
Limited space is a reality for many schools, and a large-scale Schoolyard Habitatsproject may therefore be impossible. Some schools simply have limited property,while others have dedicated much of their land to parking areas or playing fields.The common problems of limited space and/or poor soil can be overcome bymaximizing the small strips of land which are available, and by complementingthese areas with wildlife-attracting plants in containers. Growing plants incontainers is also a good way to curb competition from weeds. Many schoolshave grown thriving habitats on top of asphalt, rooftops, and paved courtyards inthis way.
Container Selection
In selecting containers, there are many options including the traditional clay orplastic pots available at any nursery. When buying plastic containers, avoid darkcolors that will absorb sunlight, and overheat the plants’ roots. Containers musthave drainage holes which are large enough for water to drain through, but smallenough so that soil is not lost through the openings. If the container has holesthat are too large, place a layer of gravel over the opening. This will prevent soilfrom washing out of the container.
The size of the container should be appropriate to the size and number of plantsthat will be placed in it. Plants are ready to be transplanted to a larger containerwhen they become root bound. Carefully hold the container upside down andgently slide the plant out. If the roots are crowded along the sides and bottom ofthe plant, it is ready to be transplanted. Plant in a container that has acircumference about two inches larger than the current pot. Fill the containerpart way with quality soil. Place the plant in the center, keeping the soil levelabout two inches below the top of the container. This will prevent the soil fromwashing away during watering. Fill in the sides of the container with more soil,and pack the soil down lightly.
Another option is to build your own wooden planter boxes. When selectinglumber, choose wood that naturally resists the damaging effects of water, such ascedar and redwood. Avoid wood treated with preservatives containingpentachlorophena or arsenic. This chemical is toxic to plant life. Containers
holding large trees should be built so they areeasy to take apart (i.e. with nuts and bolts) forperiodic root maintenance.
To make containers accessible for those inwheelchairs, mount the containers onsawhorses or wooden legs. Raised beds shouldhave 27” clearance from the ground to thebottom of the bed to be wheelchair accessible.For more information on accessible gardens,visit the American Horticultural TherapyAssociation’s website at www.ahta.org .
Soil drainage is important in allgardening, and especially so incontainer gardening. Make sure yourcontainers allow excess water to flowthrough, since water trapped at thebottom of the plant can harm, andeventually kill, some plants. To ensureproper drainage, buy pots withdrainage holes or drill holes into yourcontainers and planter boxes.
A mix of organic matter, vermiculiteand peat moss will provide good soilstructure and proper drainage.Contact your local nursery orcooperative extension office inchoosing the proper mix for yourplants. These supplies can usually bepurchased in bulk quantities at gardencenters or nurseries. Since plantsgrown in containers live in limitedamounts of soil they dry out quicklyand need to be watered often.Frequent watering, though necessary,leaches nutrients out of the soil.Replace the lost nutrients bysupplementing the soil with compost,manure, or another natural fertilizer atthe start of each growing season.
Rooftop Gardening
If your school has limited land to usefor creating a wildlife habitat andoutdoor classroom, consider creating agarden on the school rooftop. Be sureto include the maintenance facilitiespersonnel in early discussions. Roofsmust be checked for stability andleaks. Some roofs also need to beprotected from foot traffic. Plants willbe exposed to more wind and sunlighton the roof than they would be atground level. To compensate for this,choose hardier plants. Simplestructures such as wooden trellises orburlap screens can provide some windprotection and areas of shade.
Suggested ResourcesTo learn about the City of Chicago’sefforts to reduce energy demand andimprove air quality through rooftopgardens, visit:www.ci.chi.il.us/Environment/html/RooftopGarden.htmAlso visit the Rooftop GardenResource Group atwww.interlog.com/~rooftop
National Gardening AssociationOnline catalog offers severalcontainers and kits for easy-to-construct planter boxes.www.kidsgardening.com.
“Our Roof Garden location wasselected because it is our onlypossibility for green space. The nearestpark is a gated one, and therefore, wehave no access to natural spaceswithout hopping on the bus orsubway. Our location is so man-made, that I find it imperative toconnect students with the natural,living world; with the growing loss ofcommunity gardens in New YorkCity, we are forced, not unhappily, tolook skyward for green solutions.”
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