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!!!