Review of Ecological Network Principlesrandd.defra.gov.uk/Document.aspx?Document=11286_BD... · 1....

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Review of Ecological

Network Principles

Synthesising review of the use of environmental

stewardship for restoring, maintaining and enhancing a

coherent ecological network in England

Ecological Networks

• Improve the quality of current sites

• Increase the size of current sites

• Enhance connections through corridors

or stepping stones

• Create new sites

• Reduce pressures by improving the

wider environment (buffering).

Clear terminology

Zetterberg (2009) Network based tools and indicators for landscape ecological assessments, planning and design

Habitat/resource

LINK TYPE 1 between habitats

(< home range diameter)

Movement readily possible within

daily routines

1. Species requires multiple

habitats/resources

2. All species’ requirements found in a

single habitat/resource type

RESOURCE

NETWORK

(Contains a RESOURCE NETWORK

allowing one or more clusters of

reproductive units, not

necessarily a viable population)

LINK TYPE 2 between patches

(facilitating individual dispersal

movements, preventing

reproductive isolation)

(META-) POPULATION (viable

in isolation in the long-term)

Schematic showing network links relevant to the spatial organization of national populations that

could potentially be influenced by Environmental Stewardship (adapted from Zetterberg 2009)

Increasing spatial

scale of habitats and

temporal scale of

processes

META-POPULATION

LINK TYPE 3 between local

populations (making exchange

of genetic material at least

occasionally possible in the

long-term, e.g. over decades)

Habitat/resource

daily routines

habitats/resources

RESOURCE

NETWORK

Increasing spatial

temporal scale of

processes

Habitat/resource

daily routines

habitats/resources

RESOURCE

NETWORK

Increasing spatial

temporal scale of

processes

Habitat/resource

daily routines

habitats/resources

RESOURCE

NETWORK

Increasing spatial

temporal scale of

processes

Habitat/resource

daily routines

habitats/resources

RESOURCE

NETWORK

Increasing spatial

temporal scale of

processes

(GENETIC) META-POPULATION

LINK TYPE 3 between local

populations (making exchange

of genetic material at least

occasionally possible in the

long-term, e.g. over decades)

Resources habitats separated, but within

home range of species (dashed line)

Resource networks (patch)

Resource habitats adjacent and within

All resources provided by a single

habitat within home range of species

Resource network will support 1 or more reproductive units for a species

Patch Networks

Interchange of individuals between

patches (inter-generational).

Underpinning theory

A population of populations (Levins, 1969)

Persistence occurs if each patch contributes to the

persistence of at least one other patch

Extensions to classic theory

Variable patch size

Extensions to classic theory

Temporal and spatial structure

Metapopulations – Key messages

For all systems:

� Increasing patch quality & area

� Increasing connectivity

In ephemeral habitats:

� Increasing patch lifetime

� Increasing number of patches

Spatial structure & species ecology will interact.

Applicability for multiple species situations.

Connectivity

� NO general solution that will benefit all species

� Need different connections according to scale of movement

� Location of patches within the landscape is most important in determining connectivity

Sources: Bennet (2003), Szabo et al. (2007)

Corridors as linkages

� Natural corridors preferred

� Corridors increase movement by up to 50%

� Movement through similar structure habitat preferred

� Mainly foraging movements (short distances and timescales)

Sources: Gilbert-Norton et al. (2010), Eycott et al. (2010,2012)

Linear features

� Can act as natural corridors?

� Anecdotal evidence of use

� Lack of empirical evidence

Softening the matrix

� Promote similar structure to habitat of species

� Limited evidence

� Increased resources increases biodiversity

Long-Distance dispersal

Connectivity – Key messages

� Need to understand ecology of species� Foraging behaviour

� Dispersal behaviour

� Importance of landscape structure� Interacts with species ecology

� Recognise importance of long distance dispersal

Priority management actions from review

Improvement of resource quality (within a patch) and area

� Restoration of degraded patches (restore habitat)� Management of habitat in patches to improve quality

� Buffering of adverse environmental effects

� Creation of new habitat in close proximity to existing sites

For Ephemeral habitats

� Management/buffering of disturbance to increase patch longevity

� Creation of new habitat in patches

Improvement of connectivity between resources (habitat) & patches

� Creation of corridor/stepping stone patches (creation)

� Increase amount and quality of linear habitats

� Soften the matrix by improving diversity of habitats in landscape (creation of habitat)

Similar conclusions and priorities to Lawton report

Differ in terms of scale - focus here on habitats (as resource sites) rather than protected sites.

Connectivity is considered at multiple spatial scales (between habitats and between patches)

Conceptual Mapping of Ecological

Benefits from Environmental

Stewardship

Capturing the knowledge about ES

and Ecological Network Principles

• Many studies on the effectiveness of

Environmental Stewardship for it’s objectives

• Many studies on conservation of species and

habitats

• Environmental Stewardship was not designed to

be part of the conservation network

• We need to identify how the outcomes of ES

support the conservation network

• 7 Degrees of

Kevin Bacon

• Social Network

Analysis

It’s a graph Jim but not as

we know it

• Comprised of objects where pairs of objects are

connected by links

• Can be directed (A-B ≠ B-A) or undirected (A-B ≡

• Can be represented by a list of objects and a list

of links between pairs of objects

• Graphs can help capture information on and to

visualise complex systems

Graphs are in everyday

Conceptual Map

Example

Abstract: Vickery et al. (2009)Most arable field margins are sown grass strips which are limited in the avian food resources they offer

but potentially supply grass seeds and, depending on the complexity of the sward structure, a range of

arthropods. Adding perennial forbs to a grass mixture provides more diverse plant and invertebrate

food resources for birds. The availability of seeds and invertebrates on uncropped margins is strongly

influenced by management, particularly cutting, cultivation and herbicide use. Cropped margins with

reduced chemical inputs and wild bird cover crops can provide relatively high food resources

compared with a conventionally managed crop. However, resources are only present until harvest, their

plant communities are relatively poor and arthropod abundance is usually lower than in uncropped

margins.

The best winter food supplies for birds will be provided by options that create seed-rich habitats in

winter. The best summer food supplies will be provided by options that create a structurally and

floristically diverse sward. The least valuable margin in terms of food resources is a grass-only strip. On

an area-for-area basis, field margins will potentially produce food resources for birds more cost-

effectively than whole farm practices such as organic farming, though the value of margins will depend

on their management and the diversity of margin types at a farm scale. Because no single margin type

can provide the optimum year-round food supply, different types of margins should be incorporated

at the farm level, but appropriate management (and further innovation in margin design) is needed to

deliver their benefits. Field margins should be managed in conjunction with adjacent boundary

features, especially hedgerows, to create complex structures that maximise nesting opportunities for

birds and create habitats for a range of invertebrates.

Conceptual Map

(Vickery et al. 2009)

EN-ES Conceptual

Network

The work-in progress

Completed•Literature review of ES

options

•Inputted

• ES options

• Ecological Benefits

• Habitats

• Species list

To Do•Associate species with

benefits

•Associate benefits with

habitats (partial)

•Produce decision trees to

support the guidelines

Network Statistics

• 1098 Nodes

• 4080 Links

• 5 EN Principles

• 25 Habitats

• 202 ES Options

• 228 Ecological

Benefits

• 631

Species/Functional

Groups

• Rivers and Streams

• Coniferous Woodland

• Acid Grassland

• Calcareous Grassland

• Neutral Grassland

• Lowland Meadows

• Upland Hay Meadows

• Improved grassland

• Heathland

• Fen Marsh Swamp

• Bog

• Ponds

• Sand Dunes and Coastal Cliffs

Habitats

• Salt Marsh

• Scrub

• Moorland

• Farm Buildings

• Inland Rock

• Ditches

• Field Margins and Uncropped

Farmland

• Cropped Areas

• Hedgerows

• Stone Wall and Earth Bank

• Traditional Orchards

• Broadleaf and Mixed Woodland

Yellowhammer - Example

Marsh Fritillary - Example

Options associated with

management of grass sward

Direct and Indirect Benefits from EK3:

Permanent Grassland with v. low inputs

www.adas.co.uk

Guidelines for the use of ES

options in ecological networks

Part1: Selection of management

action priorities

Do plans for an

ecological network

exist?

Does the network

focus on habitats?

1. Restore degraded habitat *

2. Enhance linear features

3. Soften Matrix

Sufficient information

to identify key

limitations to

population?

Have focal species

been identified?

Use an assessment tool to target

ES option placement for resource

availability, resource connectivity

or patch connectivity

Is habitat ephemeral?

1. Manage disturbance to

increase habitat lifetime

2. Create new habitat in close

proximity to existing habitat

3. Restore degraded habitat

Do the skills exist to use GIS

mapping tools to identify

resource and patch networks?

Is the species limited

by resource

availability or

connectivity

Enhance patch connectivity:

2. Create stepping stones

3. Soften the matrix

Is limitation due

to resource

availability?

Enhance resource connectivity:

1. Create corridors (stepping stones)

1. Restore degraded habitats*

proximity to existing resource

habitat

* For restoration of degraded habitat, buffering should be used where degradation is due to adverse environmental disturbance

Resources habitats separated, but within

Resource networks (population patch)

Resource habitats adjacent and within

All resources provided by a single

habitat within home range of species

Resource network will support a population of a species

(at least 1 reproductive unit)

Limitation: Resource Availability

For non-ephemeral habitats:

1. Restore degraded (resource) habitat� Select ES options to achieve desired management

� Buffer adverse environmental disturbance

2. Create new (resource) habitat� In close proximity to existing (resource) habitat (i.e. within home range diameter)

For Ephemeral habitats:

1. Manage disturbance to increase lifetime of habitat� Select ES options to achieve desired management

� Buffer adverse environmental disturbance

2. Create new (resource) habitat� In close proximity to existing (resource) habitat (i.e. within home range diameter)

Limitation: Resource connectivity

1. Create stepping stones/corridors� Within home range diameter

2. Improve/enhance linear habitats� Especially if species known to us linear habitats for

movement

3. Soften the matrix (increase habitat diversity)� Within home range diameter

� Structurally similar to resource habitat(s)

Do plans for an

ecological network

exist?

Does the network

focus on habitats?

3. Soften Matrix

to identify key

limitations to

population?

Have focal species

been identified?

by resource

availability or

connectivity

Is limitation due

to resource

availability?

habitat

Patch Networks

Interchange of individuals between

patches (inter-generational).

Separation must be less than

dispersal distance.

Limitation: Patch Connectivity

1. Increase patch size

� Effectively increasing resource network size /

connecting resources

2. Connect patches

� Improvement/enhancement of linear features

� Create stepping stones/corridors

� Soften matrix (improve diversity of landscape)

Do plans for an

ecological network

exist?

Does the network

focus on habitats?

3. Soften Matrix

to identify key

limitations to

population?

Have focal species

been identified?

by resource

availability or

connectivity

Is limitation due

to resource

availability?

habitat

Selection of options

� Options classified by management option and broad habitat type supported

…HeathlandGrasslandWoodlandManagement Priority

…………….

…HO4, HO5, HL11,

HK6-8, HK16-

17, …

HC9, HC17,

HC21 …

Create New Habitat

…EE 1-8, HE 1-6,

HE10-11, EE12

EE 1-8, HE 1-

6, HE10-11,

EE12 …

EE 1-8, HE 1-6,

HE10-11, EE12,

EC24 - 25 …

Restore Degraded Habitat

- Buffering

…EK2, EL6, HO1 –

HO3, UL22, …

HL 9-10, HK

16-17 …

EC3,OC3,HC15-

16, HC7 …

Restore Degraded Habitat

/ Manage habitat

disturbance regime -

Management

Broad Habitat Types

Linkages - placement constraints

Type 1: Link between resources

(<= home range diameter)

WITHIN-PATCH

Type 2: Link between patches

(<= inter-generational dispersal

distance)

BETWEEN PATCHES

Species functional groups

Species Functional Groups

Home Range

Diameter (km)

50-150

150-1000

>3515-357-153-71-3<1Home Range

Dispersal Capability (km)

Species Functional Groups

Home Range

Diameter (km)

50-150

150-1000

>3515-357-153-71-3<1Home Range

Dispersal Capability (km)

Invertebrates + Reptiles + Amphibians

Characterised by:

large & open fields

for growing cereal

crops.

Characterised by:

smaller & enclosed

grassland fields for

grazing and silage.

Seasonally important

resources:

•Arable margins – EE2-3, EE8-9, EF1; HE10, HF20

•Cereal headlands – EF9-11; HF14

•Cereal-based wholecrop silage – EG4

•Ditches – EB6-7; HB14

•Hedges – EB1-3, EB14; HB11-12

•Hedges and ditches – EB8-10

•Ryegrass seed-set – EK20

•Scrub – EC4, EK1; HC15-16

•Scrub creation – HC17

•Spring cereal – EG1; HG7

•Supplementary seed – EF23; HF14

•Wild bird crops – EF2, HF12

•Wild flower strips – EF4, EE12; HE10

•Winter stubble – EF6, EF15, EF22; HG5-6

•Uncropped cultivated area – EF13

Species

All relevant ES options

What are the

network limitations for

this species?

Question

Landscape context

Yellowhammer

Fenland

arable

pastoral farm

Farm context

TYPE II

between patches:

Effectively creating new

Hedges –

EB1-3,

HB11-12

Ditches

EB6-7;

Arable margins –

EE2-3, EE8-9, EF1;

HE10, HF20Hedges

ditches –

EB8-10

Supplementary

seed –

Wild flower

strips –

EF4, EE12;

Cereal headlands –

EF9-11;

Ryegrass seed-set –

Wild bird

crops –

* For Type I links: complete networks by

adding missing features where most

required habitats are already present.

TYPE I* within resource network:

Improve local-scale connections between

habitats (local land-use heterogeneity) to

enhance habitat quality

WINTER

SPRING/SUMMER

Winter

Habitat

Quality

New farm-scale

sites with features

identified under

Type I

Breeding habitat (foraging)

Breeding habitat (nesting)

New farm-scale

sites with features

identified under

Type I

TYPE II

between patches:

Effectively creating new

TYPE I* within resource network:

Improve local-scale connections between

habitats (local land-use heterogeneity) to

enhance habitat quality

Winter

Habitat

Quality

Breeding habitat (nesting)

Bullfinch

Characterised by:

large & open fields

for growing cereal

crops.

Characterised by:

smaller & enclosed

grassland fields for

grazing and silage.

Seasonally important

resources:

Species

What are the

network limitations for

this species?

Question

Landscape context

Fenland

arable

pastoral farm

Farm context

TYPE II between patches:

Enhance habitat quality and

connectivity, and potentially create

new breeding habitat

Wild bird crops –

prefer kale and

quinoa

TYPE I within resource

network

WINTER

SPRING/SUMMER

Winter

Habitat

Quality

All relevant ES options

Hedges –

EB1-3,

HB11-12

Farm woodland creation –

HC9-10

Hedges and ditches –

EB8-10

Farm woodland –

HC12-14, HC7-8

Type I links not relevant –

All resources in one habitatType I links not relevant –

All resources in one habitat

Winter

Habitat

Quality

•Farm woodland – HC12-14, HC7-8

•Farm woodland creation– HC9-10

•Hedges – EB1-3, EB14; HB11-12

•Hedges and ditches – EB8-10

•Scrub – EC4, EK1; HC15-16

•Scrub creation – HC17

•Wild bird crops – EF2, HF12

Scrub creation

HC17Scrub –

EC4, EK1;

HC15-16

TYPE II between patches:

Enhance habitat quality and

connectivity, and potentially create

new breeding habitat

TYPE I within resource

network

www.adas.co.uk

Decision support tools

for ecological networks

Least Cost Modelling

Benefits

� Uses standard GIS software

� Uses existing land cover data

� Able to consider multiple species

� Can account for ecology of species

Drawbacks

� Limited knowledge of movement costs

� Currently only single species considered

LARCH – Landscape Ecological Analysis and

Rules for the Configuration of Habitat

LARCH – Landscape Ecological Analysis and

Rules for the Configuration of Habitat

Benefits

� Ecologically based

� Uses existing mapping

Drawbacks

� Not publicly available

� Needs specialist interpretation

� Need for high level of ecological knowledge

� Single species at a time

MulTyLink

Benefits

� Suitable for multiple species

� Freely available software(http://pascal.iseg.utl.pt/~rbras/MulTyLink/)

Drawbacks

� Large amount of pre-processing of data

� Use of costs to movement (expert opinion)

� Only identifies a single solution

� Utility depends on resolution of data (grid-based)

Other Spatial Decision Support Tools

WDC0794 – review of spatial DSTs

� Primarily concerned with ecosystem services

NatureServe Vista

� GIS toolbox

� Identifies important ecosystems

� Assess impact according to a change scenario

Polyscape

� GIS toolbox

� Incorporates least cost modelling for habitat connectivity

� Multi-objective

Breakout Session Questions� How can the guidelines be improved?

� Is the format correct?

� Are they detailed enough?

� Are they easy to use?

� Are there key scenarios for which refined guidelines should be produced?

� What options should be used to enhance grassland butterflies?

� Best methods for enhancing connectivity of habitats?

� Are there key species/species groups the guidelines should be focussed on?

� Farmland birds?

� Grassland butterflies?

� Woodland mammals?

� What are the key needs in terms of tools for network planning?� Identification of resource networks?

� Identification of patch networks?

� Easy to use?

� No specialist knowledge required?

Review of Ecological Network Principlesrandd.defra.gov.uk/Document.aspx?Document=11286_BD... · 1....

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