Forest degradation affects herbivory patterns on woody species juveniles in dry forests of central Argentina

Abstract Background Forest ecosystem structure and functioning arise from the interaction of environmental drivers operating across multiple spatial scales, with climatic factors acting broadly and anthropogenic disturbances and biotic interactions acting at smaller scales. Livestock-logging land use can alter vegetation strata coverage, height, and density, resulting in forest structural degradation. These changes may alter invertebrate herbivore assemblages and, together with domestic cattle introduction, can also modify the natural vertebrate herbivory patterns. In this context, forest structural degradation could influence herbivory pressure on woody plant juveniles (seedlings and saplings), the most vulnerable life stages that are critical for regeneration processes. In this work, we aimed to analyze the herbivory patterns by vertebrates and invertebrates on juvenile stages of woody plant species in forests under different land disturbance regimes in Chaco and Espinal dry forests of central Argentina. Results Total herbivory (vertebrates + invertebrates) on woody juveniles was higher in Espinal than in the Chaco region. In Chaco forests, total herbivory increased at higher structural degradation, whereas in Espinal it followed a unimodal pattern, peaking at intermediate structural degradation. Vertebrate and invertebrate herbivory responded differently to forest structural degradation in both regions. In Chaco forests, vertebrate herbivory increased at higher structural degradation, while invertebrate herbivory decreased at higher structural degradation. In Espinal forests, vertebrate herbivory showed a unimodal response, whereas invertebrate herbivory did not vary significantly along the structural degradation gradient. In both regions, as structural degradation intensified, herbivory damage increased more strongly on seedlings, the earliest growth stage, than on saplings. Conclusions Forest structural degradation driven by livestock and logging affects herbivory dynamics on woody plant juveniles in dry forests. By increasing vertebrate browsing pressure and reducing structural protection for young plants, degradation can intensify herbivory impacts on earlier regeneration stages. These changes may constrain woody plant recruitment and ultimately compromise long-term forest persistence and resilience.