The Speckled Caiman in Puerto Rico: Assessing abundances and densities

of an unstudied invasive species.J. Aaron HoganMichael MartyXiucheng Zeng

Department of Environmental Science, University of Puerto - Rico Río Piedras

Contents

• Introduction

• Goals & Objects

• Hypotheses

• Methodologies

• References

Introduction

The Speckled Caiman (Caiman crocodilus) was introduced to the coastal ecosystems of Puerto Rico in the 1960’s.

Figure 1. Distribution of Caiman crocodilus. Populations in Florida (USA), Puerto Rico and Cuba are introduced.—by Velasco, A. and Ayarzagüena, J. (2010).

• Caiman was sighted in at least 18 watershed localities of San Juan. 1) Laguna San José;

2) Quebrada Juan Méndez;

3) Canal Blasina;

4) Sector Bechara in Avenida Kennedy;

5) Caño Martín Peña;

6) Islote Juan Pérez in Piñones;

7) Piñones;

8) Canal Vista Mar;

9) Canal Flamboyanes;

10) Borinquen Towers;

11) Río Bayamón in Bayamón;

12) Vertedero in Carolina;

13) several other localities in Carolina;

14) Urb. Villamar in Isla Verde;

15) Ave. Roosevelt in Puerto Nuevo;

16) Ciudad Deportiva Roberto Clemente;

17) San Francisco in Río Piedras; and

18) Base Muñiz in Carolina

Are they far away from us?

Figure 2. San Juan Bay Estuary.

Why should we care?

• Caimans have been reported to: – Prey on numerous vertebrates and

invertebrates species.– Be aggressive and dangerous to humans.– Serve as vector of foreign pathogens and

diseases.

What do we already know about caiman?

• Let us build on J. Bauza R. Joglar

• WHY NOT

• What is more?

LET US

FIND OUT!!!!

Goals & Hypotheses

• Objective 1: The primary objective of this study is to document the extent of the introduced caiman population on the main island of Puerto Rico. ( Such as size, age and sex structure of the caiman population). This data can be use for further research of caiman in Puerto Rico.

• Hypothesis 1: We hypothesize that areas with closer proximity to the point of introduction (Laguna Tortugero, Manati, Puerto Rico) will have higher overall abundance and densities of specked caimans. In other words, areas further west in the SJBE will have more caimans.

Goals & Hypotheses

• Objective 2: Find out the relationship between Caiman habitat with urbanization, water quality.

• Hypothesis 2: We predict that the speckled caiman will be more abundant in disturbed areas. We also hypothesize that sites with poorer water quality will support more abundant caiman populations.

Caiman habitat

Urbani-zation

Water quality

Urbanization

Water quality

Figure 3. Relationship illustration

• Objective 3: Collect a sub sample of caimans found throughout the estuary to investigate a number of parameters. Phylogenetic bar-coding to verify species, caiman health and disease prevalence, stomach content analysis.

• Hypothesis 3: We will find caimans.

Goals & Hypotheses

http://dinets.info/crocs7.htm

Figure 4. Different species of Caiman

Methodologies

• Population quantity investigate– Spotlight boat surveys

• Conduct a series of pre-planned nightly spotlight observations.

• WE WANT TO SEE CAIMANS. WE WILL COUNT THEM AND COLLECT DATA

– Body form observation• We will approach caimans and estimate their total

length, tail length, header size, gender, etc,. The size records will be divided into 4 categories and use to speculate their age

Methodologies

• Species identification– Census counts

• We will document caimans and identify them to the best of our ability.

• Population Viability Analysis (PVA)

– Sample collection & Genetic analysis• We propose to collect a subsample of 50 caimans.

• We will collection some tissue in order to identify genetic diversity. PHYLOGENTIC IDENTIFICATION.

• American crocodiles are speculated to be living in PR.

Methodologies

• Water quality assessment– We will link water quality data from

estuario.org (SJBE program)• SJBE program has an extensive of water quality

dataset.

• Scientific obligation

– Link GIS land cover urbanization data• Extent of urbanization data are available. We

would like integrate into ULTRA (if possible)

Otherwise community involvement is our focus!

• Many projects and offer an great opportunity for citizens to integrate into the environment.

Methodologies

• Urbanization – BIG TICKET IN PUERTO RICO

• High population densities

– WHAT IS URBAN ECOLOGY?• ALONZO RAMIREZ • Biotic homogenization

– URBAN CAIMAN ECOLOGY

INTEGRATION

Student Involvement

• THIS IS EVERYTHING! Por que no?– Opportunities for research and resume

building

• We seek to employ anyone and everyone who is willing to volunteer.

• Experience la naturaleza at night. Why not count caimans…

THANK YOU!!

Refences• Ayarzagüena, J. (1984). Ecología del caimán de anteojos (Caiman crocodilus L.) en los Llanos de Apure (Venezuela).

Doñana Acta Vert. 10(3): Seville, Spain• Bayliss, P., (1987 Survey methods and monitoring within crocodile management programmes. In: Webb, G.J.W., Manolis,

S.C., Whitehead, P.J. (Eds.), Wildlife management: Crocidiles and Alligators: Surrey Beatty and Sons, Sydney, Australia, pp. 157 - 175.

• Da Silveira, R., Magnusson, W. and Campos, Z. (1997). Monitoring and distribution, abundance and breeding areas of Caiman crocodilus and Melanosuchus niger in the Anavilhanas Archipelago, Central Amazonia, Brazil. J. Herpetol. 31(4): 514-520.

• Da Silveira, R., Magnusson, W. and Thorbjarnarson, J. (2008). Factors affecting the number of caiman seen during spotlight surveys in Mamirauá Reserve, Brazilian Amazonia. Copeia 2008(2): 425-430.

• Joglar, R. RAPID ASSESMENT• Read, Mark A., et al. "The distribution and abundance of the estuarine crocodile, Crocodylus porosus, in

Queensland." Wildlife Research 31.5 (2005): 527-534.• Thorbjarnarson, J.B. (1993). Fishing behavior of spectacled caiman in the Venezuelan Llanos. Copeia 1993: 1166-1171.• Thorbjarnarson, J.B. (1994). Reproductive ecology of the spectacled caiman (Caiman crocodilus) in the Venezuelan llanos.

Copeia 1994(4): 907-919.• Tucker, Anton D., et al. (2007) "Growth dynamics of freshwater crocodiles (Crocodylus johnstoni) in the Lynd River,

Queensland." Australian journal of zoology 54.6: 409-415.• Tucker, A. D., et al. "Movements and home ranges of Crocodylus johnstoni in the Lynd River, Queensland." Wildlife

Research 24.4 (1997): 379-396.• Velasco, Alvaro, and José Ayarzagüena. (2010) "Spectacled caiman Caiman crocodilus." : 10-15. • Webb, G. J. W., S. C. Manolis, and R. Buckworth. (1983) "Crocodylus johnstoni in the McKinlay River Area N. T, III.*

Growth, Movement and the Population Age Structure." Wildlife Research 10.2: 383-401.