Geology topics

Alberto R. Puente-Rolon

Publications and source records attributed to Alberto R. Puente-Rolon.

4 recordsLinked to original sources

USGS2024

Multiple records of the introduced parthenogenetic Smooth-scaled Tegulet, Gymnophthalmus underwoodi Grant 1958, in Puerto Rico

The introduction of invasive species to islands can be devastating to local biota. While many invasive species’ successful colonization of new habitats can be attributed to features like high fecundity or low mate selectivity, parthenogenetic species pose a unique threat in their ability to reproduce asexually at high rates. The Smooth-scaled Tegulet ( Gymnophthalmus underwoodi ), first described from Barbados in the 1950s, has since been documented as an introduced species across additional Lesser and Greater Antillean islands as well as northwestern Brazil and Venezuela. Herein we report multiple individuals from Puerto Rico, including the first genetic records, which indicate that the individuals on this island are most closely related to populations recorded from Brazil and Montserrat. Additional genetic information is necessary to determine the timing and migration of this species across the Caribbean. Regardless, the continued geographic expansion of this parthenogen across the Caribbean could present a threat to local fauna.

Reptiles and Amphibians↗

USGS2017

Occupancy and abundance of Eleutherodactylus frogs in coffee plantations in Puerto Rico

Shaded coffee plantations are of conservation value for many taxa, particularly for resident avifauna in the face of extensive landscape changes. Yet, little is known about the value of coffee plantations for amphibians because there are scant demographic data to index their value among species with different habitat preferences. We estimated the probability of occupancy of three frog species: Eleutherodactylus wightmanae, a forest species; E. brittoni, a grassland species; and E. antillensis, an open habitat species. Occupancy was estimated in sun and shaded plantations, and in secondary forest, in the west-central mountains of Puerto Rico. We also estimated the probability that a survey station was occupied by no individuals, one, or >1 individual, as a proxy of abundance. The aforementioned parameters, and local colonization and extinction probability, were modeled as a function of weather conditions (temperature, humidity) and vegetation cover at the sampling station (5 m) and contextual (100 m) scales. Encounter histories were obtained with passive acoustic recorders between February and July in 2015. Consistent with known habitat preferences, the highest occupancies were associated with secondary forests for E. wightmanae and sun plantations for E. brittoni . Occupancy probability for E. antillensis was similar across habitat types, indicating no aversion to shaded–forested habitats. Shaded plantations harbored moderate levels of occupancy for all species, indicating their potential value for multispecies conservation. Local colonization rates increased with forest cover for E. wightmanae, and with open habitats for E. brittoni and E. antillensis . Open habitats harbored a higher abundance of E. brittoni and E antillensis, but lower values for E. wightmanae . Sun and shaded plantations could provide quality habitat for Eleutherodactylus spp. if managed for features that promote local colonization and abundance.

Puerto Rico↗

USGS2017

Occupancy and abundance of Eleutherodactylus wightmanae and E. brittoni along elevational gradients in west-central Puerto Rico

Populations of Eleutherodactylus species in Puerto Rico have declined in recent decades due to habitat loss and long-term climatic changes. The conservation of these habitat specialists requires an understanding of factors influencing their abundance and distribution, which at present is scant. We estimated occupancy probability and the probability of encountering ≥2 individuals of E. wightmanae (Melodius Coqui or Wightman's Robber Frog) and E. brittoni (Grass Coqui), species with contrasting habitat affinities, using multi-season, multi-state occupancy models. These parameters also served as an index of abundance (non-presence, 1, and ≥2 individuals). We modeled parameters as a function of seasonal temperature and humidity, long-term average monthly precipitation, and habitat covariates measured at survey sites along 2 elevation gradients in the southern slopes of west-central Puerto Rico. We collected survey data using passive acoustic recorders during 3 seasonal periods between February and July 2015. Occupancy patterns of both species was unimodal, containing higher probabilities (e.g., ≥0.5) at elevations between 400 m and 700 m, where long-term monthly precipitation varied between 120 mm and 160 mm. Chances of encountering ≥2 individuals increased with ground cover for E. brittoni , and decreased with increasing canopy cover for E. wightmanae . Seasonal temperature and relative humidity did not influence occupancy or the probability of encountering ≥2 individuals, likely because covariates varied within known tolerance levels for Eleutherodactylus . Our findings help reduce local extinction probability through management of habitat conditions that increase the likelihood of encountering ≥2 individuals. We also detailed an analytical framework suitable to test hypotheses aimed at predicting potential impacts from land use and climatic changes, and species responses to conservation actions.

Puerto Rico↗

USGS2012

Genetic analysis of a novel invasion of Puerto Rico by an exotic constricting snake

The tropical island Puerto Rico is potentially vulnerable to invasion by some species of exotic snakes; however, until now no established populations had been reported. Here we report and genetically characterize the nascent invasion of Puerto Rico by an exotic constricting snake of the family Boidae ( Boa constrictor ) using mtDNA and microsatellite data. Over 150 individual B. constrictor have been removed from Mayagüez municipality since May 2011, and our results from the genetic analysis of 32 individuals suggest that this population was recently founded by individuals of one subspecies from a genetic lineage common to zoo and breeding collections, but that the potential propagule pool consists of two subspecies. We also suggest that anthropogenic long-distance dispersal within the island of Puerto Rico may be occurring from the established population, with implications for further establishment across the island. This study represents the first report of the naturalization of an invasive species of boid snake in Puerto Rico and will be important in determining mitigation strategies for this invasion as well as providing a basis for comparison to other on-going studies of invasive snakes.

Biological Invasions↗