report vi tree boa centro de comercio culebra

8/9/2019 Report VI Tree BOA Centro de Comercio Culebra

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REPORT OF THE PRESENCE OR ABSENCE OF THE VIRGIN

ISLAND TREE BOA (EPICRATES MONENSIS GRANT/) AT THE PLAYA SARDINA I WARD, CULEBRA, PUERTO RICO

Prepared for:Municipality of Culcbra

Prepared by:Jose L. Herrera Giraldo

Biologist

INTRODUCTION

The Virgin Island Tree Boa (Epicrates monensis granti) (hereafter the "VI boa") is anendemic species for the Puerto Rican Bank and was listed as endangered in 1979 by theU.S. Fish and Wildlife Service under the U.S Endangered Species Act (ESA). Therestricted and fragmented distribution, the increased predation by feral mammals and thehabitat disturbance are the main factor for the endangered status. The VI boa is a nonvenomous snake that grows to slightly less than 1 m/ 39.4in of snout-vent length (SVL)(USFWS 1986) although, Tolson (2004) reported a VI boa male of SVL 1.11 m/ 43.8 infrom Steven Cay (between St. Thomas and St. John), this large male is one of the largestso far reported.

The know distribution of this snake suggest that was once more widespread on the PuertoRican Bank in most of the cays and islets throughout the archipelago (Pregill and Olson1981; Tolson 1984). The records suggest a distribution that include Rio Mar(Municipality of Rio Grande, Puerto Rico) (Garcia 1992), Cayo Ratones and Cayo Diablo(off shores cays at east of Puerto Rico), Culebra Island (Puente-Rolon 2001), St. Thomas,Tortola, Greater Camanoe, Necker Cay (Nellis et al. 1983, Laze1l2005) and Steven Cay.


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Report of the presence/absence Virgin Island Tree Boa (Epicrates mOllel1sis Kral1t,) [November 20091Playa Sardina I, Culebra, Puerto Rico

Many of the populations at these locations have been declining and some havedisappeared due to the continued habitat fragmentation and the introduction of non-nativespecies that act as competitors and/or predators.

The following report details the survey activities (presence/absence) of the VI Boa in 7acres land, where the municipality ofCulebra proposed developed an urban project thatinclude an area of 6,000 feet square.

This work is submitted in compliance with the terms and conditions of the biological opinion, which requires the survey (presence/absence) in areas designated as habitat for the VI Boa.

DESCRIPTION OF THE PROPOSED PROJECT

The proposed project (hereafter the "Centro de Comercio") will be built in an area of6000 feet squares at the Playa Sardinas I ward (Fig. 1). The Centro de Comercio willconsist of two floors with 10 locals of 500 feet squares each with a total of 5000 feetsquare and a parking and pedestrian area of 1000 feet square. The main purpose for theconstruction of this project is provide to the Culebra residents, some basic needs which atpresent can not be satisfied by a lack oflocal business. The proposed requirements to beaddressed include, barber shop, beauty salon, pharmacy, laundry, doctor, dentist, lawyer,engineer, clothing store and a fast food restaurant. The Centro de Comercio will belocated in the vicinity of some local businesses as the tire center, liquor store and cafe EIEden, D's Garden, the former facilities of the RD Medical Manufacturing, ColmadoMirka and the Villa Pesquera; the access road will be through the Calle Escudero.


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Report of the presence/absence Virgin Island Tree Boa (Epicrates monensis grant,) [November 2009)Playa Sardina I, Culebra, Puerto Rico

HABITAT DESCRIPTION OF THE PROPOSED PROJECT AREA

Culebra vegetation is subtropical dry forest type and the primarily vegetation on theproposed project area are grassland with shrubs patches (Fig 2). The area is highlydegraded with some dumping sites composed by trees cut and pieces of wood and cement(Fig. 3). The vegetation is composed by invasive species as wild tamarind (Leucaenaleucocephala) and/or exotics such as clammy cherry (Cordia ohliqua) and porknut(Acacia macracantha). The dominant vegetation height in the area rarely exceeds 3.0meters with one big tree that exceeds the 6.0 meters at the southeast of the area.

SURVEY METHODSThe survey was conducted in 7 acres land (FigA) for a period of fifteen days during themonth of October 2009. During the fifteen days, I sampled several microhabitat types forthe VI boa by walk, using Visual Encounter Sampling (VES). I focused the searches intypical snakes spots as, refuges beneath rocks, hollow trees, fallen trees, active and oldtermites nest, dumping sites, vines, trees branches, shrub vegetation and interconnectedvegetation in the canopy vines, spaces under rocks, logs retreats, artificial retreats aspiece of wood or boards. In the same way, I was turning rocks, fallen logs and allpossible elements that might provide shelter for the VI boa. The intensive searches for theVI boa were conducted from 0730 - 1130 hand 1800 - 2300 h, with a total of 110 hoursof active searches. During the day survey I search for basking snakes on old structuresnear to the local businesses especially the liquor store and cafe El Eden and near to thefence of the former facilities of the RD Medical Manufacturing. All the potential daytimerefuge was searched. During the night surveys I walked through all the potentialmicrohabitats for the VI boa (e.g. hollow trees). The period survey comprised 3 moonphase: third quarter, new moon and first quarter.


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Report of the presence/absence Virgin Island Tree Boa (Epicrates monensis granti) [November 2009)Playa Sardina I, Culebra, Puerto Rico

RESULTSDuring my fifteen surveys days no VI boas were encountered in the 7 acres surveyed.Five individuals of the Puerto Rican racer snakes Borikenophis (Alsophis)sp. weredocumented during the day and night surveys; sometimes basking or sleeping in the treebranches (Fig. 5). The Puerto Rico Giant Ameiva (Ameiva exsul) was documented onlynear to the tire center and the former facilities of the RD Medical Manufacturing (Fig 6).Several anoles such as the Puerto Rican crested Anole (Anolis cristatellus), Puerto Ricanspotted Anole (Anolis stratulus) and Puerto Rican bush Anole (A no lis pulchellus) weredetected during the day and night surveys in all the routes marked on the survey areas.Potential predators as black rats (Rattus rattus) and feral cats (Felis catus) were sightforaging in the trees branches, inside the vegetation and near to the urban structures. Nogreen iguanas (Iguana iguana) were observed in the survey areas.

With the purpose of complement the present study, I interviewed people that live or havecommercial locals around the search area related to boa sights around the study areas andthe majority of them described sightings of brown and grey large snakes in their housesor climbing trees where probably involved individuals of Puerto Rican Racers.

CONCLUSIONSThe proposed area for develop the project not appears to have the suitable habitatstructure to support VI boa populations. The dominant grassland vegetation on thebottom of the area and the absence of forested areas with structure that provide foragingsites are limiting factors for the VI boa presence. The surveyed area bordered on thesouth with private lands which present an improved habitat structure and composition andcould support VI boa populations, during my surveys several hours was spent surveyedthe VI boa at the border on private lands, but no snakes were seen.


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Report of the presence/absence Virgin Island Boa (Epicrates monensis grantl) [November 2009] Playa Sardina I, Culebra, Puerto Rico

The possible absence of the VI Boa in the proposed project site could be a combination offactors. The area is surrounded to the north and west by urban development with severaldisturbances and areas with an easy access to the public, increasing the habitatfragmentation and the threats for potential road kills. This habitat fragmentation forcesthe species to move and establish populations in forest remnants and non natural andunsuitable locations as urban areas, and in most of the cases the populations may slowlydecl ine to the point of extirpation. Another factor is the presence of predators andcompetitors such as black rats (Rattus rattus) and feral cats (FeNs calus) around theproposed area. I documented goats fecal waste in one place near to private lands at thesouth side of the search area, possibly the people that lives near to the study area havelive animals as goats. The presence of these species can cause a seriously degradation inthe vegetation composition and reduce the VI boa foraging sites, causing also a detrimentin the vegetation structure that is important for the VI boa day and night movements.Several VI boa surveys have been conducted in Culebra, but just have reported thepresence of the VI boa in five areas; Fraile ward (two areas), Punta Soldado, Resaca andClark Ward, being the Fraile ward the locality where have been documented most of thesurveys and occasional encounters with the VI boa.

REFERENCES

CITES, 1973. Convention on International Trade in Endangered Species of Wild Faunaand Flora. Signed at Washington, D.C., March 1973. Amended at Bonn, June 1979.www.cites.org

Garcia, M. A. 1992. Current status and distribution of Epicrates monensis in PuertoRico. Final Report, Project Number ES-I-8, Study IX. Puerto Rico Department ofNatural and Environmental Resources. 14 pp.
http:///reader/full/www.cites.orghttp:///reader/full/www.cites.org


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Report of the presence/absence Virgin Island Boa (Epicrates monensis grantl) [November 20091Playa Sardina I, Culebra, Puerto RicoNellis, D. W., R. L. Norton and W. P. Maclean. 1983. On the biogeography of theVirgin Islands boa, Epicrates monensis granti. 1. Herpetology 17(4): 413-417.

Pregill, G.K. and S.L. Olson. 1981. Zoogeography of West Indian land vertebrates inrelation to Pleistocene climatic cycles. Ann. Rev. Eco!. Syst. 12: 75-98.

Puente-Rolon, A. R. 2001. Current status and distribution of Virgin Island Boa (EpicratesPuerto Ricomonensis granti) in Puerto Rico. Final Report submitted to the

Department of Natural and Environmental Resources. 9 pp.

Tolson, P. 1. and 1. L. Pinero. 1985. A field report on the status of the Virgin IslandsBoa, Epicrates monensis granti, on Cayo Diablo, Puerto Rico. Report to the DepartmentofNatural Resources, Scientific Research Area, San Juan, PRo 13 pp.

Tolson, P.J. 1984. The ecology of the boid genus Epicrates in the West Indies. Abstract.Fifth Ecology Symposium. Universidad del Turabo, Departamento Ciencias yTecnologia.

Tolson, P. l. 1988. Critical habitat, predator pressures, and management of Epicratesmonensis on the Puerto Rico Bank: a multivariate analysis. Peges 228-238 In R.C.Szaro,K.E. Sevcerson, and D.R. Patton, editors. Management of amphibians, reptiles, andsmall mammals in North America. USDA Forest Service General Technical ReportRM-166

Tolson, P.l. 2004. Reintroduction Evaluation and Habitat Assessments of the VirginIslands boa, Epicrates monensis granti, on Steven Cay, U.S. Virgin Islands. FinalReport. pp. 13.

U.S. Fish & Wildlife Service. 1986. Recovery plan for the Virgin Islands Tree Boa(Epicrates monensis granti). Atlanta, Georgia. 26 pp.


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Report of the presence/absence Virgin Island Boa (Epicrates monensis granll) INovember 20091 Playa Sardina I, Culebra, Puerto Rico

Figure 2. Predominant vegetation in the proposed project site


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Report of the presence/absence Virgin Island Boa (Epicrates monensis grantl) [November 20091 Playa Sardina I, Culebra, Puerto Rico

Figure 3. Significant human damage in the proposed project site; dumping sites


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IReport of the presence/absence Virgin Island Boa (Epicrates monensis granfl) I~ o v e m b e r 2009JPlaya Sardina I. Culebra. Puerto Rico

Figure 5. Puerto Rican racer snakes Borikenophis (Alsophis) sp. during night survey

Figure 6. Individuals of the Puerto Rico Giant Ameiva (Ameiva exsul) near to the tirecenter and the former facilities of the RD Medical Manufacturing

report vi tree boa centro de comercio culebra

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