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La depredación de las ballenas asesinas sobre las nutrias marinas que unen los ecosistemas oceánicos y costeros
Science (New York, N.Y.)
|October 17, 1998
Resumen
Las poblaciones de nutrias marinas en el oeste de Alaska están disminuyendo debido al aumento de la depredación de las ballenas asesinas. Esto impacta el ecosistema cercano a la costa al aumentar los erizos marinos y reducir los bosques de algas.
Área de la Ciencia:
- Ecología marina ecología marina.
- Dinámica de las poblaciones de vida silvestre.
- Interacciones entre depredadores y presas.
Sus antecedentes:
- Las nutrias marinas (Enhydra lutris) se han recuperado de la caza excesiva histórica durante el siglo pasado.
- Las recientes disminuciones abruptas en las poblaciones de nutrias marinas se observan en el oeste de Alaska.
- Estas disminuciones tienen importantes implicaciones ecológicas para las comunidades cercanas a la costa.
Objetivo del estudio:
- Para investigar las causas de la reciente disminución de la población de nutrias marinas en el oeste de Alaska.
- Comprender los efectos en cascada de la pérdida de nutrias marinas en el ecosistema cercano a la costa.
- Identificar los potenciales impulsores de los cambios en la dinámica depredador-presa.
Principales métodos:
- Estudios de observación de las poblaciones de nutrias marinas y de la depredación de las orcas (Orcinus orca).
- Encuestas ecológicas que evalúan la densidad de erizos marinos y el estado del lecho de algas.
- Análisis de las tendencias demográficas a largo plazo y los factores ambientales.
Principales resultados:
- El aumento de la depredación de ballenas asesinas se identifica como el principal impulsor de la disminución de las nutrias marinas.
- Se han documentado densidades elevadas de erizos de mar en áreas donde la nutria de mar está en declive.
- Se ha producido una deforestación significativa de los lechos de algas, lo que indica una pérdida del papel clave de la nutria de mar.
Conclusiones:
- El declive de las nutrias marinas en el oeste de Alaska está relacionado con el aumento de la depredación de las ballenas asesinas.
- La pérdida de nutrias marinas ha interrumpido la red alimentaria cercana a la costa, lo que lleva a cambios en el ecosistema.
- Las alteraciones antropogénicas en el ecosistema oceánico marino son el probable factor de inicio de esta cascada ecológica.
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