La depredación de semillas nativas y no-nativas varía en plantaciones de pino del noroeste de la Patagonia

Abstract

Human disturbances can cause functional alterations in ecosystems, affecting key interactions such as those between plants and animals. For example, post-seed dispersal predation determines plant establishment in many terrestrial ecosystems and can have positive or negative effects on plant community composition, which can, then, influence ecosystem structure and functionality. However, seed predation can be altered in modified environments, with consequences on the establishment and dispersal of native and non-native plants. The objective of this study was to evaluate the post-dispersal predation of native and non-native seeds at different spatial scales in modified environments: pine plantations, clearcut areas and native forests in Isla Victoria, northwestern Patagonia (Argentina). We used a cafeteria-type experiment offering native and non-native seed species in each habitat and measured the vegetation cover around each seed offering area to assess the effect of microsite characteristics. After evaluating predation in the three environments, we only found that there is a greater preference for predation of native seeds in pine forest plantations. On the other hand, we identified that vegetation cover at ground level (strongly correlated with the type of environment) keeps a positive relationship with seed predation. This study shows that seed predation of native and non-native plants could be driven in part by microsite characteristics (greater plant cover = greater seed predation), perhaps through generating refuge (safe site) for the main seed predators of these forests (i.e., rodents). Forest conservation, management and restoration strategies must consider the short- and long-term dynamics of a post-intervention restoration site with the aim of creating an environment conducive to native forest regeneration.