INSTITUTO ARGENTINO DE NIVOLOGIA, GLACIOLOGIA Y CIENCIAS AMBIENTALES
Unidad Ejecutora - UE
congresos y reuniones científicas
Ctenomys mendocinus, a keystone species and an ecosystem engineer at the south of the Puna
BORGHI C; BORRUEL N; ANDINO N; CANOVAS G; RODRIGUEZ NAVAS A; AGÜERO G; SRUR A.M.; RIVERO C; DÍAZ G
Congreso; 10° Congreso Internacional de Mamíferos; 2009
Keystone species are those species whose impact on its community or ecosystem in a manner disproportionately large in relation to its abundance. Ecosystem engineer species are those who modulate directly or indirectly the availability of resources to other species, by causing physical state changes in biotic or abiotic materials. Many studies have suggested that others subterranean rodents could be considered as ecosystem engineers. Within this framework, we studied the role of Ctenomys in the functioning of the Puna ecosystem, at the Reserva Don Carmelo, San Juan, Argentina at 3150 m asl. We found that Ctenomys activities modified soil, vegetation structure, plant survival, floration, fructification, seed production and seedling emergence. It also indirectly modified the thermal landscape by its effect on the substrate and plant cover. As a combination of their effect as keystone species and an ecosystem engineer, their indirect effects modify plant composition, plant cover, and the distribution and abundance of animal species. For example, increasing relative abundances of lizard (e.g. Liolaemus ruibali), modified habitat use of big mammals like guanacos (Lama guanicoe), or birds as Oreopholus ruficollis, Muscisaxicola alpina and Geositta cunicularia. The activity of Ctenomys switches from a community structured by bottom up process (growth limiting resources like water and temperature) toward a community structured by top down process (by herbivory of Ctenomys population). Then, Puna populations can be under a dual control by resources and subterranean herbivores in a cycle of approximately 5 years long.