Distribution and abundance of four caiman species (Crocodylia: Alligatoridae) in Jaú National Park, Amazonas, Brazil

Rebêlo, George Henrique; Lugli, Luciana

dc.creator	Rebêlo, George Henrique
dc.creator	Lugli, Luciana
dc.date	2015-02-06
dc.date.accessioned	2016-05-03T15:32:07Z
dc.date.available	2016-05-03T15:32:07Z
dc.identifier	http://revistas.ucr.ac.cr/index.php/rbt/article/view/18061
dc.identifier.uri	https://hdl.handle.net/10669/27231
dc.description	Jaú National Park is a large rain forest reserve that contains small populations of four caiman species. We sampled crocodilian populations during 30 surveys over a period of four years in five study areas. We found the mean abundance of caiman species to be very low (1.0 ± 0.5 caiman/km of shoreline), independent of habitat type (river, stream or lake) and season. While abundance was almost equal, the species’ composition varied in different waterbody and study areas. We analysed the structure similarity of this assemblage. Lake and river habitats were the most similar habitats, and inhabited by at least two species, mainly Caiman crocodilus and Melanosuchus niger. However, those species can also inhabit streams. Streams were the most dissimilar habitats studied and also had two other species: Paleosuchus trigonatus and P. palpebrosus. The structure of these assemblage does not suggest a pattern of species associated and separated by habitat. Trends in species relationships had a negative correlation with species of similar size, C. crocodilus and P. trigonatus, and an apparent complete exclusion of M. niger and P. trigonatus. Microhabitat analysis suggests a slender habitat partitioning: P. trigonatus was absent from river and lake Igapó (flooded forest), but frequent in stream Igapó. This species was the most terrestrial and found in microhabitats similar to C. crocodilus (shallow waters, slow current). Melanosuchus niger inhabits deep, fast moving waters in different study areas. Despite inhabiting the same waterbodies in many surveys, M. niger and C. crocodilus did not share the same microhabitats. Paleosuchus palpebrosus was observed only in running waters and never in stagnant lake habitats. Cluster analysis revealed three survey groups: two constitute a mosaic in floodplains, (a) a cluster with both M. niger and C. crocodilus, and another (b) with only C. crocodilus. Athird cluster (c) included more species, and the presence of Paleosuchus species. There was no significant difference among wariness of caimans between disturbed and undisturbed localities. However, there was a clear trend to increase wariness during the course of consecutive surveys at four localities, suggesting that we, more than local inhabitants, had disturbed caimans. The factors that are limiting caiman populations can be independent of human exploitation. Currently in Amazonia, increased the pressure of hunting, habitat loss and habitat alteration, and there is no evidence of widespread recovery of caiman populations. In large reserves as Jaú without many disturbance, most caiman populations can be low density, suggesting that in blackwater environments their recovery from exploitation should be very slow.	en-US
dc.description	Jaú National Park is a large rain forest reserve that contains small populations of four caiman species. We sampled crocodilian populations during 30 surveys over a period of four years in five study areas. We found the mean abundance of caiman species to be very low (1.0 ± 0.5 caiman/km of shoreline), independent of habitat type (river, stream or lake) and season. While abundance was almost equal, the species’ composition varied in different waterbody and study areas. We analysed the structure similarity of this assemblage. Lake and river habitats were the most similar habitats, and inhabited by at least two species, mainly Caiman crocodilus and Melanosuchus niger. However, those species can also inhabit streams. Streams were the most dissimilar habitats studied and also had two other species: Paleosuchus trigonatus and P. palpebrosus. The structure of these assemblage does not suggest a pattern of species associated and separated by habitat. Trends in species relationships had a negative correlation with species of similar size, C. crocodilus and P. trigonatus, and an apparent complete exclusion of M. niger and P. trigonatus. Microhabitat analysis suggests a slender habitat partitioning: P. trigonatus was absent from river and lake Igapó (flooded forest), but frequent in stream Igapó. This species was the most terrestrial and found in microhabitats similar to C. crocodilus (shallow waters, slow current). Melanosuchus niger inhabits deep, fast moving waters in different study areas. Despite inhabiting the same waterbodies in many surveys, M. niger and C. crocodilus did not share the same microhabitats. Paleosuchus palpebrosus was observed only in running waters and never in stagnant lake habitats. Cluster analysis revealed three survey groups: two constitute a mosaic in floodplains, (a) a cluster with both M. niger and C. crocodilus, and another (b) with only C. crocodilus. Athird cluster (c) included more species, and the presence of Paleosuchus species. There was no significant difference among wariness of caimans between disturbed and undisturbed localities. However, there was a clear trend to increase wariness during the course of consecutive surveys at four localities, suggesting that we, more than local inhabitants, had disturbed caimans. The factors that are limiting caiman populations can be independent of human exploitation. Currently in Amazonia, increased the pressure of hunting, habitat loss and habitat alteration, and there is no evidence of widespread recovery of caiman populations. In large reserves as Jaú without many disturbance, most caiman populations can be low density, suggesting that in blackwater environments their recovery from exploitation should be very slow.	es-ES
dc.format	application/pdf
dc.language	eng
dc.publisher	Universidad de Costa Rica	en-US
dc.rights	Copyright (c) 2015 International Journal of Tropical Biology and Conservation	en-US
dc.source	Revista de Biología Tropical/International Journal of Tropical Biology and Conservation; Vol. 49 (3-4) December 2001; 1095-1109	en-US
dc.source	Revista de Biología Tropical/International Journal of Tropical Biology and Conservation; Vol. 49 (3-4) December 2001; 1095-1109	es-ES
dc.source	Revista Biología Tropical; Vol. 49 (3-4) December 2001; 1095-1109	pt-PT
dc.source	2215-2075
dc.source	0034-7744
dc.subject	reptilia	en-US
dc.subject	crocodylia	en-US
dc.subject	amazonia	en-US
dc.subject	abundance	en-US
dc.subject	richness	en-US
dc.subject	wariness	en-US
dc.subject	jau national park	en-US
dc.subject	brazil	en-US
dc.title	Distribution and abundance of four caiman species (Crocodylia: Alligatoridae) in Jaú National Park, Amazonas, Brazil	en-US
dc.title	Distribution and abundance of four caiman species (Crocodylia: Alligatoridae) in Jaú National Park, Amazonas, Brazil	es-ES
dc.type	artículo original

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