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Results for “Caribbean Journal of Science”

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At least 19 recordsLinked to original sources
USGS2005

Diversity and abundance of forest frogs (Anura: Leptodactylidae) before and after Hurricane Georges in the Cordillera Central of Puerto Rico

Caribbean hurricanes often impact terrestrial vertebrates in forested environments. On 21 September 1998, Hurricane Georges impacted Puerto Rico with sustained winds in excess of 166 km/hr, causing damage to forests of the island's principal mountain range; the Cordillera Central. We estimated forest frog abundance and diversity from call counts conducted along marked transects before and after Hurricane Georges in two forests reserves of the Cordillera Central (Maricao and Guilarte). We used distance sampling to estimate density of Eleutherodactylus coqui and recorded counts of other species. After the hurricane, the abundance of E. coqui increased in both reserves compared to prehurricane levels while abundance of other frog species decreased. In Maricao, relative abundance of E. richmondi (P = 0.013) and E. brittoni (P = 0.034) were significantly lower after the hurricane. Moreover, species richness and evenness of the Maricao and Guilarte frog assemblages declined after the hurricane. Our results on abundance patterns of the forest frog assemblages of Maricao and Guilarte Forests were similar to those reported from the Luquillo Experimental Forest after Hurricane Hugo in September 1989. Long-term demographic patterns of the forest frog assemblages in the Cordillera Central may be associated with changes due to the ecological succession in post-hurricane forests. Copyright 2005 College of Arts and Sciences.

Caribbean Journal of Science↗
USGS2008

Land cover and forest formation distributions for St. Kitts, Nevis, St. Eustatius, Grenada and Barbados from decision tree classification of cloud-cleared satellite imagery

Satellite image-based mapping of tropical forests is vital to conservation planning. Standard methods for automated image classification, however, limit classification detail in complex tropical landscapes. In this study, we test an approach to Landsat image interpretation on four islands of the Lesser Antilles, including Grenada and St. Kitts, Nevis and St. Eustatius, testing a more detailed classification than earlier work in the latter three islands. Secondly, we estimate the extents of land cover and protected forest by formation for five islands and ask how land cover has changed over the second half of the 20th century. The image interpretation approach combines image mosaics and ancillary geographic data, classifying the resulting set of raster data with decision tree software. Cloud-free image mosaics for one or two seasons were created by applying regression tree normalization to scene dates that could fill cloudy areas in a base scene. Such mosaics are also known as cloud-filled, cloud-minimized or cloud-cleared imagery, mosaics, or composites. The approach accurately distinguished several classes that more standard methods would confuse; the seamless mosaics aided reference data collection; and the multiseason imagery allowed us to separate drought deciduous forests and woodlands from semi-deciduous ones. Cultivated land areas declined 60 to 100 percent from about 1945 to 2000 on several islands. Meanwhile, forest cover has increased 50 to 950%. This trend will likely continue where sugar cane cultivation has dominated. Like the island of Puerto Rico, most higher-elevation forest formations are protected in formal or informal reserves. Also similarly, lowland forests, which are drier forest types on these islands, are not well represented in reserves. Former cultivated lands in lowland areas could provide lands for new reserves of drier forest types. The land-use history of these islands may provide insight for planners in countries currently considering lowland forest clearing for agriculture. Copyright 2008 College of Arts and Sciences.

Caribbean Journal of Science↗
USGS2009

Extensive coral mortality in the US Virgin Islands in 2005/2006: A review of the evidence for synergy among thermal stress, coral bleaching and disease

In the summer/fall of 2005, extensive coral bleaching on reefs in the US Virgin Islands (USVI) was associated with sea water temperatures exceeding 30°C. Almost all coral species bleached, including Acropora palmata , which bleached for the first time on record in the USVI. As water temperatures cooled, corals began to regain their normal coloration. However, a severe disease outbreak then occurred on deeper, non-acroporid reefs. The disease demonstrated signs consistent with white plague. Monitoring of coral cover along previously established long-term transects on several reefs in St. John and St. Croix was intensified. Data on bleaching and disease were collected before, during and after this bleaching/disease episode. Average coral cover declined by over 50%, from 21.4% to 10.3% at the long-term study sites, within one year of the onset of bleaching, declining further to 8.3% after two years. This loss of coral cover was greater than from all other stressors affecting the USVI reefs in preceding years, and no significant recovery is evident. Disease prevalence increased on bleached A. palmata colonies that were being monitored as well as on the colonies of other species on the deeper reefs. Bleached A. palmata colonies had more disease (primarily white pox and other un-described diseases) than unbleached colonies. The non-acroporid corals that bleached most severely suffered the highest mortality from disease. Although the research summarized in this paper is not conclusive, the results suggest that high water temperatures lead to bleaching, which weakens corals and makes them more vulnerable to diseases.

U.S. Virgin Islands↗
USGS2012

Diet of the invasive Cuban treefrog (Osteopilus septentrionalis) in pine rockland and mangrove habitats in South Florida

Native to Cuba, the Bahamas and the Cayman Islands, the Cuban Treefrog (CTF) is an invasive species in Florida, with the ability to inflict serious ecological damage to invaded habitats. By examining the diet of the CTF, a known predator of native frogs, better predictions may be made of the impacts on native species and ecosystems. From 2002 - 2003, CTF diet was investigated in south Florida at four sites, two each within pine rockland and mangrove habitat. Within each habitat, one site exhibited a low density of CTFs and the other a high density of CTFs. CTFs were captured in PVC pipes attached to trees and stomach contents were examined after euthanasia. Beetles were the most numerous and widely consumed prey item among sites; roaches, orthopterans, spiders, ants, and caterpillars were also major dietary components. There were significant differences in the proportion of taxa consumed by CTFs between low and high density populations within each habitat, with the low density site in every instance having the higher proportion. Across habitats, ants comprised a significantly higher proportion of the diet in mangroves, whereas beetles, orthopterans, and snails comprised a significantly higher proportion of the diet in pine rocklands. Approximately 3.5% of all stomachs examined contained anuran remains. Though not significant, CTFs from low density sites consumed a higher proportion of frogs than those at high density sites. Corroborating previous research, the data show the CTF to be a generalist feeder, consuming a wide variety of invertebrate prey, with anurans playing only a minor role in the overall diet.

Florida↗
USGS2021

Statistical methods used in research concerning endangered and threatened animal species of Puerto Rico: A meta-study

A concern about statistics in wildlife studies, particularly of endangered and threatened species, is whether the data collected meet the assumptions necessary for the use of parametric statistics. This study identified published papers on the nine endangered and six threatened species found only on Puerto Rico using five different databases. The results from the Zoological Record database identified the most articles, including all identified by the other databases. Of the 222 identified articles, 108 included some form of statistics, 26 used only descriptive statistics, 34 included only parametric statistics, 26 used only nonparametric statistics, and 22 reported both parametric and nonparametric statistical analyses. This meta-study showed that the percentage of articles with no statistical treatment decreased in the most recent 20 years, and that although parametric statistics continue to be the most commonly used in published wildlife studies of Puerto Rican wildlife, there has been a distinct increase in the use of nonparametric statistics over time.

Caribbean Journal of Science↗
USGS2022

Atlantic spotted and bottlenose dolphin sympatric distribution in nearshore waters off Bimini, The Bahamas, 2003–2018

Within nearshore waters off Bimini, The Bahamas, Atlantic spotted ( Stenella frontalis ) and common bottlenose ( Tursiops truncatus ) dolphins are sympatric but separated spatially in different geographic areas and water depth ranges. Afternoon surveys during summer months across a 16-year period showed S. frontalis used the northern part of the nearshore area more, while T. truncatus used the southern area more. Generally, examination of geographic zones and water depth distributions of both species before and after construction of a pier in the study area suggested these dolphins were not impacted, long-term, by this anthropogenic activity. Still some differences in use of the nearshore area were identified. For water depth, S. frontalis varied use between 5–<12 m and 12–<20 m, depending on location along the coast. In contrast, T. truncatus consistently used the 5–<12 m depths. This difference may be related to how each species used the nearshore area, with T. truncatus feeding more and S. frontalis travelling and doing other activities. A small change in the distribution of S. frontalis by water depth off the northern coast of Bimini was found, specifically an increased use of deeper (12–20 m) water post 2014, which is unlikely an effect of pier construction as S. frontalis continued to use the 5–12 m depths as they had before pier construction. How this change might be related to an unprecedented 2013 S. frontalis immigration event, which might have disrupted the social structure, habitat/resource use, and distribution of both species, is discussed.

Bimini↗
USGS2023

Geographic distribution of the Puerto Rican Harlequin Butterfly (Atlantea tulita): An ensemble modeling approach

Species distribution models have become increasingly important tools for species conservation. This modeling approach can help guide conservation practitioners and inform decisions. Distribution models are particularly relevant for rare species, whose habitat associations are often not well understood. Using species occurrence data, and a variety of predictor variables, we developed three individual distribution models and a weighted ensemble model for the Puerto Rican harlequin butterfly ( Atlantea tulita ). The ensemble model had the greatest accuracy (AUC = 0.92). Further, the ensemble model indicated 7.1% of the main island of Puerto Rico encompassed suitable habitat for the harlequin butterfly. However, only 0.5% was classified as including the greatest suitability. Using an ensemble modeling approach to delineate areas of the island with suitable environmental conditions may improve habitat conservation efforts for the species.

Caribbean Journal of Science↗
USGS2025

Being loud to find a quiet bird: Surveying a secretive tropical avian species

Secretive birds are hard to detect, and thus, likely underestimated when surveyed, potentially preventing measures to protect them. We identified a sampling period and method that would yield the most reliable estimates of population numbers of the secretive Puerto Rican Lizard-Cuckoo ( Coccyzus vieilloti ). We addressed these objectives by comparing point counts (passive) and playback broadcast (active) survey methods from January to December, 2022 at Cambalache State Forest, Puerto Rico. We surveyed 20 stations (radius = 50 m each) between sunrise and 10 am, employing the time-of-detection method. We recorded strong responses from C. vieilloti after birds had been stimulated by playback broadcasts (recapture probabilities), corresponding to a behavioral response (M b ). For example, average capture (p) and recapture (c) probabilities within the peak breeding season for active surveys were 0.23 ± 0.10 and 0.49 ±0.08, respectively. Active surveys yielded higher estimates of C. vieilloti compared to passive surveys. For example, active survey expected population numbers (15.6 ha or area sampled) during peak breeding season were 42.87 ± 12.08 compared to 19.60 ± 2.08 individuals from passive surveys. Coefficients of variation population estimates of active surveys ranged between 10 and 16%, with one exception (28%), well within acceptable levels for wildlife studies. We show that secretive species like C. vieilloti can be reliably surveyed using playback broadcasts. Surveys should be conducted during the peak breeding season when estimates are higher and have better precision. Conducting similar tests on other secretive species could ensure that their status is not mischaracterized and that they receive the benefits of appropriate conservation measures, if warranted.

Cambalache State Forest, Puerto Rico↗
USGS2003

New record of the rare emballonurid bat Centronycteris centralis Thomas, 1912 in Costa Rica, with notes on feeding habits

The shaggy sac-winged bat, Centronycteris centralis, occurs mainly in lowland forests from Veracruz, Mexico, to Peru, although it has been reported from elevations as high at 1450 m in Panama. Most captures of the species are of single individuals, and throughout its distribution, this bat is rare and poorly-known. Centronycteris centralis generally has been assumed to be an aerial insectivore, capturing flying insects on the wing. However, direct evidence supporting this trophic role has been lacking. Herein, I report on a specimen of C. centralis from seasonally-inundated swamp forest in the Caribbean lowlands of northeastern Costa Rica that provides valuable information on distribution, morphological variation, reproduction, and feeding habits of this species.

Caribbean Journal of Science↗
USGS2001

Population size, survival, and movements of white-cheeked pintails in Eastern Puerto Rico

We estimated numbers and survival of White-cheeked Pintails (Anas bahamensis) in eastern Puerto Rico during 1996-1999. We also quantified their movements between Culebra Island and the Humacao Wildlife Refuge, Puerto Rico. Mark-resight population size estimates averaged 1020 pintails during nine, 3-month sampling periods from January 1997 to June 1999. On average, minimum regional counts were 38 % lower than mark-resight estimates (mean = 631). Adult survival was 0.51 ?? 0.09 (SE). This estimate is similar for other anatids of similar size but broader geographic distribution. The probability of pintails surviving and staying in Humacao was hiher (67 %) than for counterparts on Culebra (31 %). The probability of surviving and moving from Culebra to Humacao (41 %) was higher than from Humacao to Culebra (20 %). These findings, and available information on reproduction, indicate that the Humacao Wildlife Refuge refuge has an important role in the regional demography of pintails. Our findings on population numbers and regional survival are encouraging, given concerns about the species' status due to habitat loss and hunting. However, our outlook for the species is tempered by the remaining gaps in the population dynamics of pintails; for examples, survival estimates of broods and fledglings (age 0-1) are needed for a comprehensive status assessment. Until additional data are obtianed, White-cheeked Pintails should continue to be protectd from hunting in Puerto Rico.

Caribbean Journal of Science↗
USGS2003

Influence of salinity and temperature on the physiology of Limia melanonotata (Cyprinodontiformes: Poeciliidae): A search for abiotic factors limiting insular distribution in Hispaniola

We investigated salinity and temperature effects on routine metabolic rate (RMR), temperature tolerance (CTMax, critical thermal maximum), and salinity tolerance of Limia melanonotata, a poecliid fish that occurs in west-central inland waters of Hispaniola. Routine metabolic rate and CTMax were measured in fish acclimated to three salinities (0, 30, and 60 ppt) and temperatures (25??, 30??, and 35??C) for nine temperature-salinity combinations. Salinity and temperature did not significantly interact in their effect on RMR. For combined salinity acclimations, adjusted RMR (ANCOVA) was significantly lower at 25??C than either 30?? or 35??C. For combined temperature acclimations, mean RMR was significantly lower at 60 ppt than either 0 or 30 ppt. Salinity and temperature had a significant interactive effect on temperature tolerance. Mean CTMax was significantly higher at 30?? than 25??C at all salinities, but at 35??C was significantly higher than at 25?? or 30??C only among fish acclimated in fresh water. Fish exposed to a chronic increase in salinity experienced most mortality in a salinity range of 70-107 ppt, with females exhibiting greater salinity tolerance than males. Limia melanonotata approaches the upper extreme in salinity and temperature tolerances known for poeciliids. Our results also suggest that L. melanonotata may reduce energy expenditures at environmental extremes to tolerate harsh conditions for extended periods. Despite its curythermal and euryhaline adaptations, L. melanonotata has a relatively restricted inland range in Hispaniola and is unknown from inshore brackish or marine habitats. The present distribution of this species and congeners may be the result of a combination of factors that include historical zoogeography and ecological requirements.

Caribbean Journal of Science↗
USGS2003

Habitat association, size, stomach contents, and reproductive condition of Puerto Rican boas (Epicrates inornatus)

The Puerto Rican boa occurs in a variety of habitats, including wet montane forest, lowland wet forest, mangrove forest, wet limestone karst, and offshore cays, and from sea level to 480 m. Mean SVL of 49 encountered boas (live and road-killed) was 136.9 ?? 35.1 (range = 38.8-205 cm), with a mean mass of 952.1 ?? 349.0 g (n = 47; range = 140-1662 g). Prey in digestive tracts (n = 29) included remains of black rats, house mice, three species of anoles, bats, common ground-doves, domestic fowl chicks, and invertebrates. Females were in reproductive condition in late April through mid-August and had an average brood size of 21.8 ?? 6.0 (n = 9, range = 13-30 ).

Caribbean Journal of Science↗