Geology topics

Jaime A. Collazo

Publications and source records attributed to Jaime A. Collazo.

58 records · Page 4Linked to original sources

USGS2012

Science summary in support of Manatee Protection Area (MPA) design in Puerto Rico

The Antillean manatee (Trichechus manatus manatus), a subspecies of the West Indian manatee, is listed as endangered by the US Department of Interior. In accordance with its listing, the U.S. Fish and Wildlife Service’s Caribbean Field Office (USFWS) is mandated to create one or more Manatee Protection Areas (MPAs) for Puerto Rico. Designation of these areas must comply with the legal definition of an MPA’s purpose: to prevent or reduce take of manatees (CFR 50: 44 FR 60964, Oct. 22, 1979). To meet this goal, we pursued two objectives: 1) identify areas which include the specific ecological attributes necessary to support manatee populations, and 2) identify areas where take can be reduced through approved MPA regulatory frameworks. We achieved these objectives through literature review, expert elicitation, and geospatial modeling. This report delivers to USFWS a set of nine potential MPA regions. These regions represent the spatial realization of experts’ hypotheses regarding manatee requirements and threats, and the potential to implement MPA strategies (e.g. watercraft access, speed regulations, signage and boater education). The nine regions are compared based on a number of factors, including their potential to reduce take, quality of the habitat encompassed, and total area. These maps and statistics serve as suitable starting points to select one or more MPA sites, but we recommend that the mapped attributes and threats (i.e., boating activity) of MPAs be ground-truthed to visually confirm the local presence of resources, threats, and manatees before any area is selected. Once established, the effectiveness of MPAs can be monitored and updated through processes of adaptive monitoring and management. Aerial surveys, radio tracking studies, and public surveys are all valuable tools to assess the success of an MPA. Establishing MPAs is a management action that, integrated within the species Recovery Plan, should enhance the conservation of manatees.

Cooperator Science Series↗

USGS2012

Use of occupancy models to evaluate expert knowledge-based species-habitat relationships

Expert knowledge-based species-habitat relationships are used extensively to guide conservation planning, particularly when data are scarce. Purported relationships describe the initial state of knowledge, but are rarely tested. We assessed support in the data for suitability rankings of vegetation types based on expert knowledge for three terrestrial avian species in the South Atlantic Coastal Plain of the United States. Experts used published studies, natural history, survey data, and field experience to rank vegetation types as optimal, suitable, and marginal. We used single-season occupancy models, coupled with land cover and Breeding Bird Survey data, to examine the hypothesis that patterns of occupancy conformed to species-habitat suitability rankings purported by experts. Purported habitat suitability was validated for two of three species. As predicted for the Eastern Wood-Pewee ( Contopus virens ) and Brown-headed Nuthatch ( Sitta pusilla ), occupancy was strongly influenced by vegetation types classified as “optimal habitat” by the species suitability rankings for nuthatches and wood-pewees. Contrary to predictions, Red-headed Woodpecker ( Melanerpes erythrocephalus ) models that included vegetation types as covariates received similar support by the data as models without vegetation types. For all three species, occupancy was also related to sampling latitude. Our results suggest that covariates representing other habitat requirements might be necessary to model occurrence of generalist species like the woodpecker. The modeling approach described herein provides a means to test expert knowledge-based species-habitat relationships, and hence, help guide conservation planning.

Avian Conservation and Ecology↗

USGS2005

Survival of captive-reared Puerto Rican Parrots released in the Caribbean National Forest

We report first-year survival for 34 captive-reared Puerto Rican Parrots ( Amazona vittata ) released in the Caribbean National Forest, Puerto Rico between 2000 and 2002. The purpose of the releases were to increase population size and the potential number of breeding individuals of the sole extant wild population, and to refine release protocols for eventual reintroduction of a second wild population elsewhere on the island. After extensive prerelease training, we released 10 parrots in 2000, 16 parrots in 2001, and eight parrots in 2002 ranging in age from 1–4 years old. All birds were equipped with radio-transmitters to monitor survival. The overall first-year survival estimate for the 34 parrots was 41% (CI = 22%–61%). Only one parrot died within the first week postrelease, with most (94%) surviving for at least eight weeks after release. Most (54%) documented mortalities were due to raptor predation, which claimed 21% of all released parrots. A captive-reared bird (male, age one), released in 2001, paired with a wild female and fledged two young in 2004. We also calculated survival based on 0% and 50% of observed predation losses and found hypothetical survival rates of 72% and 54%, respectively. Rigorous prerelease training and acclimation was believed to have improved initial postrelease parrot survival, and releasing mixed age-class groups suggests the potential for shortening the time to recruitment.

Puerto Rico↗

USGS2005

Habitat use, movements and home range of wintering Lesser Scaup in Florida

Radio telemetry and diurnal time activity budgets were used to show that wintering Lesser Scaup ( Aythya affinis ) used different habitats for comfort and feeding activities at Merritt Island National Wildlife Refuge (Merritt Island), Florida and adjacent estuarine areas. Management should take this spatial consideration into account. The same data were used to determine if habitat use differed between sexes. Data on movements and home range were used to evaluate habitat quality and potential effects of human disturbance. Scaup foraged more in impounded wetlands and rested more in open estuarine regions. Mean distance between diurnal and nocturnal sites was 2.7 km (SE ± 0.3), and was similar between sexes and from mid to late winter. Male and female fixed kernel home ranges and core use areas did not differ. Mean fixed kernel 95% home range and 50% core use areas were 15.1 km 2 (SE ± 2.0) and 2.7 km 2 (SE ± 0.5) respectively, representing 3% and 0.5% of surveyed habitats. Males and females used habitats similarly and short distances traveled between diurnal and nocturnal sites suggested that habitat conditions were similar across the impounded wetlands and shallow portions of both the Indian River and Banana River. Sedentary or short movements suggested that disturbance was probably negligible at the principal areas used by Lesser Scaup. Habitat management strategies for scaup should not be restricted to Merritt Island. Adjustments should be made to take into account that maintenance activities occur in adjacent estuarine areas as well.

Florida↗