Effective population size of broad-snouted caiman (Caiman latirostris) in Brazil: A historical and spatial perspective

Zucoloto, Rodrigo Barban; Bomfim, Gilberto Cafezeiro; Fernandes, Flora Maria de Campos; Schnadelbach, Alessandra Selbach; Piña, Carlos Ignácio; Verdade, Luciano Martins

doi:10.1016/j.gecco.2021.e01673

Cited by 4 publications

(1 citation statement)

References 44 publications

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“…In the mid-twentieth century, hunting pressure seriously depleted their populations throughout their range , and since then, this practice has been banned. Although several of its populations showed signs of recovery, the effective number of breeders is still low today (Zucoloto et al 2021).…”

Section: Introductionmentioning

confidence: 99%

Stage-based model of population dynamics and harvest of Broad-snouted caiman (<i>Caiman latirostris<i>) under different management scenarios

Viotto¹,

Navarro²,

Simoncini³

et al. 2023

Ethnobio Conserv

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We created a matrix model structured by stages (divided into 5 stages) to evaluate the population dynamics of Caiman latirostris and the population behavior at different management intensities through ranching and hunting of adult individuals. We generated 5000 matrices by sampling the mean and variance values of survivals (p i ) and hatching for each stage. For each matrix, we obtained the growth rate λ and performed elasticity analyses. Modifying the mean matrix obtained from the previous analysis, we evaluated different scenarios of ranching, reintroduction, and hunting of adult females of the last two stages (E) raised here (class III animals, > 60 cm snout-vent length, divided into two: E4 and E5). We obtained a mean λ of 1.035 (range 0.88 − 1.12), and 11.9% of the simulations had λ < 1.The vital rate with the highest elasticity and variance was that of the adult females of the last stage.Natural populations can tolerate a maximum of 5% adult female hunting, and ranching can extract 55% of nests from the wild without reintroduction or 80% of nest harvest, returning to the wild at least 3% of hatched animals in the ranching programs. Our model showed that hunting and ranching with reintroduction are feasible strategies to be applied without threatening natural populations. Increasing reintroduction makes it possible to extract more adult individuals and maintain the species' populations at sustainable levels.

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Section: Introductionmentioning

confidence: 99%

Stage-based model of population dynamics and harvest of Broad-snouted caiman (<i>Caiman latirostris<i>) under different management scenarios

Viotto¹,

Navarro²,

Simoncini³

et al. 2023

Ethnobio Conserv

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Assessing abundance–suitability models to prioritize conservation areas for the dwarf caimans in South America

Rodriguez‐Cordero,

Balaguera‐Reina,

Gross

et al. 2024

Ecology and Evolution

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Species–environment relationships have been extensively explored through species distribution models (SDM) and species abundance models (SAM), which have become key components to understand the spatial ecology and population dynamics directed at biodiversity conservation. Nonetheless, within the internal structure of species' ranges, habitat suitability and species abundance do not always show similar patterns, and using information derived from either SDM or SAM could be incomplete and mislead conservation efforts. We gauged support for the abundance–suitability relationship and used the combined information to prioritize the conservation of South American dwarf caimans (Paleosuchus palpebrosus and P. trigonatus). We used 7 environmental predictor sets (surface water, human impact, topography, precipitation, temperature, dynamic habitat indices, soil temperature), 2 regressions methods (Generalized Linear Models—GLM, Generalized Additive Models—GAM), and 4 parametric distributions (Binomial, Poisson, Negative binomial, Gamma) to develop distribution and abundance models. We used the best predictive models to define four categories (low, medium, high, very high) to plan species conservation. The best distribution and abundance models for both Paleosuchus species included a combination of all predictor sets, except for the best abundance model for P. trigonatus which incorporated only temperature, precipitation, surface water, human impact, and topography. We found non‐consistent and low explanatory power of environmental suitability to predict abundance which aligns with previous studies relating SDM‐SAM. We extracted the most relevant information from each optimal SDM and SAM and created a consensus model (2,790,583 km2) that we categorized as low (39.6%), medium (42.7%), high (14.9%), and very high (2.8%) conservation priorities. We identified 279,338 km2 where conservation must be critically prioritized and only 29% of these areas are under protection. We concluded that optimal models from correlative methods can be used to provide a systematic prioritization scheme to promote conservation and as surrogates to generate insights for quantifying ecological patterns.

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Phylogenetic identity and population structure of the dwarf caimans Paleosuchus spp. in the Orinoco basin of Colombia and Venezuela: filling gaps

Hernández-Rangel,

Morales-Betancourt,

Muniz

et al. 2023

Biological Journal of the Linnean Society

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Dwarf caiman species of the genus Paleosuchus (Paleosuchus palpebrosus and Paleosuchus trigonatus) are old, widespread crocodilian lineages with populations affected by habitat modification. For both species, phylogeographical studies revealing crucial information have already been performed, but for important ecoregions, such as the Orinoco, knowledge is lacking. In this study, the phylogenetic identity of individuals of Paleosuchus spp. from the Orinoco basin of Colombia and Venezuela was evaluated. The genetic structure of the two species of Paleosuchus was also determined and their genetic diversity quantified. The results show a marked genetic structuring in both species, also indicating that the populations of P. trigonatus and P. palpebrosus of the Orinoco basin are well differentiated from those of other hydrographic basins. For Colombia, it was possible to infer that there are two independent management units for both species (Orinoco and Amazonas) and that the populations of the Orinoco basin present high genetic and haplotypic diversity. In Venezuela, only one management unit was identified for each species. This finding, together with the results of previous studies, show that, in total, there are at least five management units for P. palpebrosus and six for P. trigonatus, throughout their distribution areas. It is necessary to take this information into account when establishing conservation strategies for these species, although it is stressed that the geographical sampling must be improved in future phylogeographical studies, because information gaps persist at the geographical level.

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Effective population size of broad-snouted caiman (Caiman latirostris) in Brazil: A historical and spatial perspective

Cited by 4 publications

References 44 publications

Stage-based model of population dynamics and harvest of Broad-snouted caiman (<i>Caiman latirostris<i>) under different management scenarios

Stage-based model of population dynamics and harvest of Broad-snouted caiman (<i>Caiman latirostris<i>) under different management scenarios

Assessing abundance–suitability models to prioritize conservation areas for the dwarf caimans in South America

Phylogenetic identity and population structure of the dwarf caimans Paleosuchus spp. in the Orinoco basin of Colombia and Venezuela: filling gaps

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