Mackin W.A.,Guilford College |
Moore P.,Bahamas National Trust |
Lee D.S.,Tortoise Reserve |
Ferguson L.M.,Biodiversity Research Institute |
Ferguson L.M.,Wetlands Institute
Waterbirds | Year: 2015
The Cay Sal Bank in The Bahamas is one of the Caribbean region's most important areas for breeding seabirds, but the colonies previously lacked solid estimates. This paper describes results of four visits between 2010 and 2012. The Santaren Channel, used to transit to and from Cay Sal Bank, contained high numbers (6.1 ± 0.4 birds per km2) of seabirds. The Cay Say Bank has at least 117 detectable islands with 484 ha of land area; the most numerous colony was at Elbow Cay (23 ha). Audubon's Shearwaters (Puffinus lherminieri) were breeding at 97 pairs per ha (total: 2,200; 95% CI = 1,650-2,800 pairs), Sooty Terns (Onychoprion fuscatus) at 382 pairs per ha (total: 8,800; 95% CI = 6,900-10,700 pairs), Bridled Terns (Onychoprion anaethetus) at 38 pairs per km coastline (5,829 m coastline; total: 220; 95% CI = 145-295 pairs) and Brown Noddies (Anous stolidus) at 72 pairs per ha (total: 1,609; 95% CI = 1,070-2,250 pairs). The population of Audubon's Shearwaters is among the largest in the world while populations of the other species are regionally significant. Roughly 420 ha (87% of the available land) were visited; however, many of the smaller cays (43 islands with 30 ha of habitat) have still not been surveyed. Seabirds were present in low densities (0.3-20 total pairs per ha) on the other large islands, all of which contain populations of introduced black (Rattus rattus) or Norway (R. norveigicus) rats. These visits provide the first repeatable surveys of breeding seabirds at Cay Sal Bank. © 2015, BioOne. All rights reserved.
Krysko K.L.,University of Florida |
Steadman D.W.,University of Florida |
Nunez L.P.,University of Florida |
Lee D.S.,Tortoise Reserve
Zootaxa | Year: 2015
We document the first specimen of a dipsadid snake from the Anguilla Cays, Cay Sal Bank, The Bahamas. We analyze 3,426 base pairs (bp) of sequence data derived from five mitochondrial loci and one nuclear locus using Maximum Likelihood (ML) and Bayesian Inference (BI) methods. Our molecular data agree with some aspects of morphology (e.g., scale counts, dentition, and color pattern) supporting identification of this specimen as the Cuban Racer, Cubophis cantherigerus cantherigerus (Bibron 1840), a species previously regarded as endemic to Cuba. This discovery provides another example of the strong Cuban affinities of the terrestrial vertebrate fauna of Bahamian islands. Copyright © 2015 Magnolia Press.
Haney J.C.,Defenders of Wildlife |
Lee D.S.,Tortoise Reserve
Marine Ornithology | Year: 2015
The expense of conducting dedicated marine bird surveys creates incentives to optimize sampling effort. We appraised spatiotemporal effort in two shipboard surveys off the southeastern coast of the United States using analyses of seabird community structure. By applying randomization routines from both data-analytic (curve-fitting) and sampling-theoretic methods (bootstrap, jackknife, coverage), we assessed sampling adequacy for estimating numerical and biomass dominance, species accumulation rates and species richness. Maximum-likelihood estimators indicated that each survey had been carried out long enough for cumulative species richness (Sobs) to reach an apparent asymptote. Data stratification by season did not reduce the asymptotic-based estimates of minimum survey effort overall. Three estimators of total species richness (Ŝmax) were equal to or less than values actually observed (Sobs = 53 species in each survey). Five other estimators of Ŝmax exceeded Sobs by 5%–18%, suggesting few species remained undetected by the time our surveys ended. Indeed, after >600 additional observation days, only six more offshore species were detected (all extralimitally rare), a tally that fell within error terms for estimators noted above. The two avifaunal surveys examined here were two to six times longer than required (36–65 days) to detect community dominants (species comprising ≥95% of numerical abundance and biomass). We conclude that sampling effort as appraised by community attributes was minimally adequate in both surveys. Measures of saturation in community structure can be applied while inventories are in progress to complement analyses of sample size based on statistical power, and may help minimize costs associated with over-sampling in dedicated surveys for marine birds. © 2015, Marine Ornithology. All rights reserved.