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The Mona Project: Studying effects of a grass invasion at Mona Island
Reserve:
Lead PI’s Elvia Meléndez-Ackerman 1,2 Denny Fernández 1,3
1 Institute for Tropical Ecosystem Studies – UPR-Río Piedras2 Center for Applied Tropical Ecology and Conservation (CATEC) - UPR-
Río Piedras3 Wildlife Management Program, UPR-Humacao
Isla de Mona
Grass invasions and negative effects Changes in
disturbance regimes
Loss of biota (through competitive exclusion, habitat change)
Changes in ecosystem function
Cactus/Cactus/Cactus-Shrub Cactus-Shrub ForestForest
Harrisia portoricensis
Endemic to Puerto Rico
Threatened species status since 1990 (USFW)
Threats: Habitat lost
Geographically restricted to Mona, Monito and Desecheo Island
Presence of feral goats and pigs – USFW, 1990; Melendez-Ackerman et. Al. 2007
Presence of invasive grass species (Megathyrsus maximus). Studies Led by Julissa Rojas (PhD Student)
What is the performance of Harrisia portoricensis within
the context of :
•Habitat modification by an invasive grass?
•Climate variability?
6 permanent georeferenced plots established in Mona Island
769 tagged plants Seedlings <5cm Juveniles <50cm Adults >50cm
Low shrub/cactus forest
Megatyrsus maximum area
Native platform forest
High density of Harrisia
Low density of Harrisia
Martinuzzi et al. 2008
Martinuzzi et al. 2008
Grass Treatments
No Grass
v
Partial Trimming
(PT)
Positive Control (PC)
CompleteRemoval (PR)
Large-Scale Experiment
Design:
12 Plots Maintained monthly since January 200812 Micromet stations at each (PAR, Soil Temp, Soil Humidity)1 Meterological Statioon (Air Temp, % Rel Humidity, Precipitation)
Areas invadidas de pasto: implicaciones para Harrisia
Harrisia
Área invadida de Megathrysus maximus
Months 2008
Ene Feb Mar Abr May Jun Jul Ago Sep Oct
Gra
ss
Bio
ma
ss
(g
)
0.0
0.2
0.4
0.6
0.8
1.0
1.2
Mm intactMm cutMm removed
Grass biomass (+/- SE) per management treatment
10 sampling monthsXavier Jaime et. al – UPR-Humacao
ANOVA PMes 0.3912Treat. 0.0171
Soil mesofauna at grass invaded sites
Moreno et. al. – UPR Río PiedrasLastra and Meléndez-Ackerman - UPR Rií Piedras
-
Species Richness - Soil Fauna
Block
Num
ber
of S
peci
es
0
2
4
6
8
10
12
14
16
18
20
GrassNo Grass
Grass Effects - Posters
Additional projects: Telemetry studies on feral goat movements and rock iguanas (Lopez MSc;
Figuerola PhD)
Reproductive Ecology of Guaiacum sanctum (Fumero-Caban PhD)
Foraging behavior of polyginous Solenopsis invicta in Puerto Rico (Orengo MSc)
Long-term climatic trends and its relation to population dynamics in Lepanthes rupestris (Olaya, MSc.)
Cave arthropods’s diversity in the Northern Karst (Toro BSc)
Ecophysiology of the exotic tree Spathodea campanulata (UPR-Humacao, BSc.)
Extracting precipitation information from radar Satellite Imagery (UPR-Humacao BSc.)
Acknowledgements
CATEC NSF-CRESTNSF-Puerto Rico Alliance for Minority ParticipationNSF –Undergraduate Mentoring in Environmental BiologyESA-SEEDSFord Motor CompanyAKKA-SEEDSMany collaborators and volunteers!!!