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Genetic diversity and population structure of Amazonian crocodilians
Author(s) -
Farias Izeni P.,
Silveira Ronis,
Thoisy Benoit,
Monjeló Luis A.,
Thorbjarnarson John,
Hrbek Tomas
Publication year - 2004
Publication title -
animal conservation
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.111
H-Index - 85
eISSN - 1469-1795
pISSN - 1367-9430
DOI - 10.1017/s136794300400143x
Subject(s) - population , generalist and specialist species , habitat , habitat fragmentation , biology , geography , genetic diversity , range (aeronautics) , ecology , wildlife corridor , amazon rainforest , zoology , demography , materials science , sociology , composite material
We used the mitochondrial cytochrome b gene to study the population genetic structure of Melanosuchus niger (Brazil: Negro and Purus Rivers, Lake Janauacá; French Guiana: Kaw River swamps), and Caiman crocodilus (Brazil: Purus River, Lake Janauacá; French Guiana: Kaw River swamps). We found 10 haplotypes in M. niger and 9 haplotypes in C. crocodilus . Nested clade analysis indicated that isolation‐by‐distance was an important population dynamic in M. niger , but was unable to differentiate between isolation‐by‐distance, historical fragmentation or range expansion in C. crocodilus . Fu's Fs statistic supported the hypothesis of a demographic expansion in one out of four and two out of three sampled localities of M. niger and C. crocodilus , respectively. Populations of M. niger in central Amazonia also appeared to show differentiation that was correlated with water type. These results are compatible with the life‐style of these two crocodilians; C. crocodilus is a habitat generalist and appears to disperse rapidly to newly available habitats, while M. niger is a more sedentary habitat specialist. Both species appear to be recovering from unregulated over‐harvesting, however, their responses are life‐history and, potentially, ecologically‐dependent.