mona island iguana and hawskbill seaturtle population viability analyses m. hernández 1,3, m. e....

Mona Island Iguana and Mona Island Iguana and Hawskbill SeaTurtle Hawskbill SeaTurtle

Population Viability AnalysesPopulation Viability Analyses

M. Hernández 1,3, M. E. Pérez1,3, M.A.García 2, 3, A.O. Alvarez 2,

R L. Tremblay3,4

C. E. Diez 2,3 and R. van Dam 5 , N. Perez-Buitrago6

1 Department of Mathematics-University of Puerto Rico-Rio Piedras Campus2 Department of Natural and Environmental Resources, Puerto Rico3 Center for Applied Tropical Ecology and Conservation-University of Puerto Rico4 Department of Biology-University of Puerto Rico-Humacao Campus5 Chelonia Inc.6 Department of Biology-University of Puerto Rico –Rio Piedras Campus

Mona Island Iguana (MIA)Mona Island Iguana (MIA)Cyclura cornuta stejnegeriCyclura cornuta stejnegeri

Status

distribution limited to 55 km2

estimated population of 4,000 to 5,000 individuals

low recruitment of juveniles

FactorsFactors

Introduction of exotic species of flora and fauna

- high mortality from predation

- possible competition for food

- destruction of nests and reduction of nesting areas

HeadstartHeadstartA conservation strategy

consisting of keeping hatchlings in captivity until they reach a size that is less vulnerable to early age-class predators

Headstart Facilities

1999 2000

Summary Summary Mona Island IguanaMona Island IguanaHeadstart (HST) started in 1999

> 200 HST releasedMultiple recapturesHigh survivability and wild breedingEmphasis on increasing HST diversity (collecting sites)On going a comprehensive Population Viability Analysis (PVA)

Mona Island Iguana PVAMona Island Iguana PVATwo Objectives

◦Determine # of HST iguanas required to maintain a positive population growth toward the recovery goal (effective population size?)

◦Identify key life stages or demographic processes to allocate resources and management strategies

PVAPVACollaborative Effort

◦University of PR-Río Piedras Campus Department of Mathematics

◦University of PR-Humacao Campus◦CATEC (CREST Funding)◦Department of Natural Resources

and Environment (DNER)

Bayesian Bayesian analysis of trajectories analysis of trajectories after after release for headstarted Mona Island Iguana release for headstarted Mona Island Iguana

As part of the evaluation of the headstart program, it is desired to compare release sites.

Bayesian models are used for analyzing trajectories of released individuals which have been followed using radio transmitters. Similar trajectories in both release sites could be interpreted as similar behavior.

These models incorporate as explanatory variables:

•Release site •Sex•Body mass at release time

1

Trajectories for the headstarted Mona Island iguanas, Trajectories for the headstarted Mona Island iguanas, Corral Wiewandt release site,Corral Wiewandt release site,females (solid lines) and males (dashed lines). females (solid lines) and males (dashed lines).

Trajectories for the headstarted Mona Island iguanas, Carabinero release site,

females (solid lines) and males (dashed lines).

Bayesian analysis for the growth of Mona Island iguana in headstart facility (Cyclura cornuta stejnegeri)

M. Hernández 1,3, M. E. Pérez1,3, García, M.A. 2, 3, A.O. Alvarez 3,

R L. Tremblay3,4

1 Department of Mathematics-University of Puerto Rico-Rio Piedras Campus

2 Department of Natural and Environmental Resources, Puerto Rico

3 Center for Applied Tropical Ecology and Conservation-University of Puerto Rico

4 Department of Biology-University of Puerto Rico-Humacao Campus

2

It is desired to predict how long it will take for an animal to achieve the minimum size required for release. In early stages a linear growth equation can be a good approximation.

Projects Projects StudentsStudentsDemography and microhabitat use

◦ Cielo Figuerola (Ph.D student)

Modelling iguana growth and dispersal◦ Mariely Hernández (Master Mathematics --May 2010)

Relationship between adult size and clutch / ≈ PVA hawksbill◦ Gloriell Cardona (First year graduate)

Modelling population parameters of wild iguanas population◦ Keyla Pagán (Ph. D student)

AccomplishmentsAccomplishmentsPosters

Presentations