Oil exploitation drives environmentally- and trait-mediated diversity of non-native plants in the Yungas forest in Argentina

Abstract

Anthropogenic disturbances profoundly affect forest ecosystems worldwide. Oil exploitation is one of the major stressors driving the high co-occurrence of different non-native plant species in the Yungas forest of Calilegua National Park, Argentina. Using a dataset of records collected from 2010 to 2020, we evaluated environmental drivers and oil exploitation activity shaping the occurrence and diversity of non-native plant species in 18 study sites. To do so, we first compared species richness and diversity at different levels of anthropogenic disturbance. Then, we used regression models to investigate species-environment relationships. Lastly, a fourth corner analysis was applied to investigate how the interaction between explanatory variables and plant functional traitsshapes the occurrence of the studied non-native plant species. We found that oil exploitation activities promoted the diversity of non-native plants in the protected area. Presence of the three most widespread non-native plant species was influenced by the topographic slope andorganic matter content. The fourth corner analysis further showed that the positive interaction between plant N-fixation capacity with either close proximity to oil boreholes, a low organic matter content or a high coverage of herbs positively affected the presence of non-native plant species.To our knowledge, this is the first time that trait-environment relationships under a gradient of anthropogenic disturbance were investigated to explain the occurrence and diversity of non-native plant species. Given that abundant non-native plant species have partially overlapping niches in the Yungas transition forests, it is advisable that future restoration actions focus on groups of non-native plants rather than single species. Addi­tionally, non-native plant species of concern, which are able to successfully establish in both disturbed and undisturbed areas require adapted eradication measures.