Abundance and distribution trends of the West Indian manatee in the coastal zone of Belize: implications for conservation.

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Title: Abundance and distribution trends of the West Indian manatee in the coastal zone of Belize: implications for conservation.
Author: Auil, Nicole Erica
Abstract: The coastal zone of Belize is home to the largest recorded number of the threatened Antillean manatee (Trichechus manatus manatus ) within the species' Caribbean range . The objectives of my study were : (1 ) to determine long -term trends in aerial survey counts and indices of the manatee population in the coastal zone of Belize ; and (2 ) to examine the seasonal change in manatee distribution among habitats in the coastal zone . Standardized extended -area aerial surveys were conducted along the entire coastline of Belize in the dry and wet seasons of 1997 , and 1999 - 2002 . Manatees were counted in five habitat categories : cay , coast , estuary , lagoon , and river . Total sightings per survey ranged from 90 to 338 ; the greatest number was counted in the 2002 wet season . Calf percentage ranged from 5 to 13 . A slight negative trend in total counts was significant for dry -season , not wet -season surveys , indicating an interactive effect of season and year . Based on analysis of variance , the Abundance Index (transformed manatee sightings per hour ) did not differ significantly among years , although it varied significantly within year by season and habitat by season . In applying a spatial approach , the general survey route was buffered 1 km on both sides , and 1 km grids were overlaid and classified by habitat type . The presence or absence of each cell for each survey was used in likelihood ratio tests of the single and interactive effect of season and habitat . The Index for river habitat was higher in the dry season , while cay habitat was higher in the wet season . Overall , near -shore habitat (estuary , lagoon , and river ) showed a higher Index than did the offshore habitat (cay and coast ) although the total number of sightings was higher offshore . Considering the interactive effect of year , season , and habitat , long -term studies are needed , in both seasons , and among all habitats to account for variation . Continued broad -scale surveys , along with metapopulation analysis would fine -tune the understanding of specific sites , enhancing integrated coastal zone management for protected species and their habitat systems .
URI: http : / /hdl .handle .net /1969 .1 /560
Date: 2004-09-30

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Abundance and distribution trends of the West Indian manatee in the coastal zone of Belize: implications for conservation.. Available electronically from http : / /hdl .handle .net /1969 .1 /560 .

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