Regional habitat conservation priorities for the American crocodile

Thorbjarnarson, John B.; Mazzotti, Frank J.; Sanderson, Eric W.; Buitrago, Fabio; Lazcano, Marco; Minkowski, Karen; Muñiz, Manuel; Ponce, Paulino; Sigler, Luis; Soberon, Roberto; Trelancia, Ana Maria; Velasco, Álvaro

doi:10.1016/j.biocon.2005.09.013

Cited by 87 publications

(88 citation statements)

References 6 publications

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“…From a conservation perspective, hybridization is particularly concerning when one species is extremely rare and the other is more abundant (Rhymer and Simberloff, 1996;Allendorf et al, 2001). In terms of New World crocodiles, there is evidence of hybridization involving two range-restricted species, the Cuban crocodile (C. rhombifer; Varona, 1966;Weaver et al, 2008;Milián-García et al, 2011) and Morelet's crocodile (C. moreletii; Hekkala, 2004;Ray et al, 2004;Cedeño-Vazquez et al, 2008;Rodriguez et al, 2008;Machkour-M'Rabet et al, 2009) with overlapping populations of the American crocodile (C. acutus), that is more broadly distributed in North America, South America and the Caribbean (Ramos et al, 2004;Thorbjarnarson et al, 2006).…”

Section: Introductionmentioning

confidence: 99%

Genetic evidence of hybridization between the critically endangered Cuban crocodile and the American crocodile: implications for population history and in situ/ex situ conservation

et al. 2014

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Inter-specific hybridization may be especially detrimental when one species is extremely rare and the other is abundant owing to the potential for genetic swamping. The Cuban crocodile (Crocodylus rhombifer) is a critically endangered island endemic largely restricted to Zapata Swamp, where it is sympatric with the widespread American crocodile (C. acutus). An on-island, C. rhombifer captive breeding program is underway with the goals of maintaining taxonomic integrity and providing a source of individuals for reintroduction, but its conservation value is limited by lack of genetic information. Here we collected mtDNA haplotypic and nuclear genotypic data from wild and captive C. rhombifer and C. acutus in Cuba to: (1) investigate the degree of inter-specific hybridization in natural (in situ) and captive (ex situ) populations; (2) quantify the extent, distribution and in situ representation of genetic variation ex situ; and (3) reconstruct founder relatedness to inform management. We found high levels of hybridization in the wild (49.1%) and captivity (16.1%), and additional evidence for a cryptic lineage of C. acutus in the Antilles. We detected marginally higher observed heterozygosity and allelic diversity ex situ relative to the wild population, with captive C. rhombifer exhibiting over twice the frequency of private alleles. Although mean relatedness was high in captivity, we identified 37 genetically important individuals that possessed individual mean kinship (MK) values lower than the population MK. Overall, these results will guide long-term conservation management of Cuban crocodiles for maintaining the genetic integrity and viability of this species of high global conservation value.

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Section: Introductionmentioning

confidence: 99%

Genetic evidence of hybridization between the critically endangered Cuban crocodile and the American crocodile: implications for population history and in situ/ex situ conservation

et al. 2014

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“…The absence of these alleles in the analysis could help explain the loss of genetic variation observed in these localities. Crocodylus acutus populations declined range-wide through the mid-20 th century as a result of hunting and illegal poaching (Ross 1998;Thorbjarnarson et al 2006;Thorbjarnarson 2010). These human activities have not been documented in Costa Rica; however, it is possible that populations here experienced similar pressures and population declines.…”

Section: Discussionmentioning

confidence: 99%

“…Effective management strategies for threatened and endangered species require integration of all aspects of the species' biology, including both demography and genetics (Lande 1988) The American crocodile (Crocodylus acutus) is mainly a coastal species ranging from the extreme southern tip of Florida, through the Caribbean, and Central and northern South America (Mazzotti 1999;Thorbjarnarson 2010). Populations rangewide are threatened by habitat destruction and fragmentation, poaching, and past overexploitation (Ross 1998; Thorbjarnarson et al 2006;Mazzotti et al 2007). Current threats to C. acutus in Costa Rica include habitat loss (particularly nesting habitat), deliberate killing (Machkour-M' Rabet et al 2009), and pollution (Rainwater et al 2007;Rainwater et al 2011).…”

Section: Introductionmentioning

confidence: 99%

Conservation genetics of American crocodile, Crocodylus acutus, populations in Pacific Costa Rica

Mauger¹,

Vélez²,

Cherkiss³

et al. 2017

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Maintaining genetic diversity is crucial for the survival and management of threatened and endangered species. In this study, we analyzed genetic diversity and population genetic structure at neutral loci in American crocodiles, Crocodylus acutus, from several areas (Parque Nacional Marino Las Baulas, Parque Nacional Santa Rosa, Parque Nacional Palo Verde, Rio Tarcoles, and Osa Conservation Area) in Pacific Costa Rica. We genotyped 184 individuals at nine microsatellite loci to describe the genetic diversity and conservation genetics between and among populations. No population was at Hardy-Weinberg Equilibrium (HWE) over all loci tested and a small to moderate amount of inbreeding was present. Populations along the Pacific coast had an average heterozygosity of 0.572 across all loci. All populations were significantly differentiated from each other with both F ST and R ST measures of population differentiation with a greater degree of molecular variance (81%) found within populations. Our results suggest C. acutus populations in Pacific Costa Rica were not panmictic with moderate levels of genetic diversity. An effective management plan that maintains the connectivity between clusters is critical to the success of C. acutus in Pacific Costa Rica.

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“…Historically, the American crocodile (Crocodylus acutus Cuvier, 1807) has faced serious population declines throughout its range as a result of human persecution, overexploitation and habitat loss (Thorbjarnarson et al 2006). In some countries, such as Colombia, illegal killing of this keystone species and intentional destruction of its habitat continue to threaten local populations (Thorbjarnarson et al 2006), thereby compromising aquatic ecosystems health and equilibrium in these regions.…”

Section: Introductionmentioning

confidence: 99%

“…In some countries, such as Colombia, illegal killing of this keystone species and intentional destruction of its habitat continue to threaten local populations (Thorbjarnarson et al 2006), thereby compromising aquatic ecosystems health and equilibrium in these regions.…”

Section: Introductionmentioning

confidence: 99%

A three-year mark-recapture study in a remnant population of Crocodylus acutus Cuvier in Portete Bay (Guajira, Colombia)

Espinosa

Bertin

Gómez³

et al. 2012

Gayana (Concepc.)

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RESUMENEl Cocodrilo Americano Crocodylus acutus, ha experimentado importantes declines poblacionales a lo amplio de su distribución debido a la persecución humana, la sobreexplotación y la pérdida de hábitat. C. acutus permanece en peligro crítico en algunos países tales como Colombia donde la ausencia de estudios detallados sobre su ecología y distribución constituyen una de las barreras principales para el desarrollo de efectivas estrategias de conservación. Durante tres años desarrollamos un estudio de captura-recaptura para investigar el estatus demográfi co de C. acutus e identifi car las variables medioambientales más infl uyentes en su distribución en Bahía Portete (Colombia). Nosotros estimamos que la población de cocodrilos es relativamente pequeña (< 140 animales), incluye muy pocos adultos y demuestra un fuerte défi cit de hembras en la clase juvenil. La humedad relativa y la temperatura promedio del aire estuvieron positivamente correlacionadas con el número de avistamientos de cocodrilos. Por el contrario, la salinidad promedio del agua se encontró relacionada con la baja probabilidad de observación, presumiblemente debido a la preferencia de los juveniles por áreas de baja salinidad. Nuestros resultados sugieren que la población de C. acutus en Bahía Portete está en riesgo y puede requerir la intervención humana para asegurar su persistencia.Palabras claves: Captura-recaptura, cocodrilo, variables medioambientales, manglar ABSTRACTThe American crocodile, Crocodylus acutus, has experienced important population declines worldwide due to human persecution, overexploitation and habitat loss. C. acutus remains critically endangered in some countries such as Colombia where the lack of detailed surveys on its ecology and distribution constitutes a major barrier to the development of effective conservation strategies. We conducted a three-year capture-recapture study to investigate the demographic status of C. acutus and to identify environmental variables likely to infl uence its distribution in Portete Bay (Colombia). We estimated the crocodile population to be relatively small (< 140 animals), to include very few adults, and to demonstrate a very strong defi cit in females in the juvenile class. Both mean air temperature and relative humidity were positively correlated with the number of sightings. In contrast, mean water salinity was found to decrease the probability of observing a crocodile, presumably due to juvenile preference for low salinity areas. Our fi ndings suggest that the population of C. acutus in Portete Bay is at risk and may require human intervention to assure its persistence.

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Regional habitat conservation priorities for the American crocodile

Cited by 87 publications

References 6 publications

Genetic evidence of hybridization between the critically endangered Cuban crocodile and the American crocodile: implications for population history and in situ/ex situ conservation

Genetic evidence of hybridization between the critically endangered Cuban crocodile and the American crocodile: implications for population history and in situ/ex situ conservation

Conservation genetics of American crocodile, Crocodylus acutus, populations in Pacific Costa Rica

A three-year mark-recapture study in a remnant population of Crocodylus acutus Cuvier in Portete Bay (Guajira, Colombia)

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