Ecología reproductiva y cacería de la tortuga T rachemys scripta (Testudinata: Emydidae), en el área de la Depresión Momposina, norte de Colombia
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Bernal Múnera, Marcela
Daza R, Juan Manuel
Páez, Vivian P.
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Universidad de Costa Rica
Abstract
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Se estudió la ecología reproductiva de la tortuga ico- tea, Trachemys scripta callirostris, durante la estación re- productiva del 2000, en una localidad de la Depresión Momposina, al norte de Colombia. Se examinó el número de nidos en áreas con características diferentes, el éxito de 17 eclosión y las causas de mortalidad natural de los huevos. Se determinó el efecto de la explotación sobre las pobla- ciones de hembras anidantes en dos localidades con dife- rentes tasas de cacería. Los resultados mostraron que la mayor cantidad de nidos se encontraron entre los primeros 20 m, a partir de la orilla de los cuerpos de agua, en sitios con sustratos de humedad moderada y textura limoso-are- nosa, cubiertos con vegetación rastrera. Los invertebrados produjeron la mayor mortalidad en las nidadas. El éxito de eclosión de la población estudiada fue mayor en compara- ción con otros informes de la misma especie. En el sitio que presenta mayor presión de caza se encontró una corre- lación negativa entre la tasa de cacería y los días transcu- rridos desde el inicio de la temporada de anidación, lo que probablemente se deba a que la extracción excesiva dismi- nuye la cantidad de hembras anidantes hacia el fin de la temporada. Las hembras del sitio con mayor explotación, presentaron una talla significativamente menor con rela- ción a las del sitio con menor caza. Las hembras, neonatos y nidadas de toda la zona, mostraron menor tamaño que las de otras poblaciones tropicales del mismo género. La pro- longada presión de caza en el norte de Colombia parece ser un factor de alteración de la estructura y la dinámica po- blacional de T. scripta callirostris.
We studied the reproductive ecology of the slider turtle, Trachemys scripta callirostris, during the reproductive season of the year 2000, in an area of the Mompós Depression, northern Colombia. We examined the number of nests ovoposited in locations with different characteristics, their hatching success rates and the natural causes of egg mortality. We also determined the effects of exploitation of nesting females, in two popu- lations with different levels of harvesting. The results showed that the majority of nests were laid along bodies of water, in the first 20 m of the shoreline, in sites with substrates of moderate humidity, sand and clayish tex- ture, covered by creeping vegetation. Invertebrates produced the greatest mortality in the nests. Hatching suc- cess was high, compared to other reports for this species. Only in the site with the highest hunting pressure, a negative correlation was found, between the harvest rate and the time elapsed since the start of the nesting peri- od, suggesting that the excessive extraction decreased the number of nesting females. Also, the females from the highly exploited site were significantly smaller than those from the less exploited site. The females, neonates and nests of the entire area, exhibited sizes below that reported for other tropical populations of the genus. The continued hunting pressure in northern Colombia, appears to be a factor that has altered the structure and popu- lation dynamics of T. scripta callirostris.
We studied the reproductive ecology of the slider turtle, Trachemys scripta callirostris, during the reproductive season of the year 2000, in an area of the Mompós Depression, northern Colombia. We examined the number of nests ovoposited in locations with different characteristics, their hatching success rates and the natural causes of egg mortality. We also determined the effects of exploitation of nesting females, in two popu- lations with different levels of harvesting. The results showed that the majority of nests were laid along bodies of water, in the first 20 m of the shoreline, in sites with substrates of moderate humidity, sand and clayish tex- ture, covered by creeping vegetation. Invertebrates produced the greatest mortality in the nests. Hatching suc- cess was high, compared to other reports for this species. Only in the site with the highest hunting pressure, a negative correlation was found, between the harvest rate and the time elapsed since the start of the nesting peri- od, suggesting that the excessive extraction decreased the number of nesting females. Also, the females from the highly exploited site were significantly smaller than those from the less exploited site. The females, neonates and nests of the entire area, exhibited sizes below that reported for other tropical populations of the genus. The continued hunting pressure in northern Colombia, appears to be a factor that has altered the structure and popu- lation dynamics of T. scripta callirostris.
Keywords
testudinata, emydidae, trachemys scripta callirostris, nesting, reproductive success, hunting, colombia