Are nests microhabitats? Assessing the importance of Caiman latirostris nests in areas with different levels of anthropogenic disturbance

Abstract

Wild vertebrates face increasing threats from human activities, particularly land-use changes, which disrupt ecological interactions and ecosystem structure. Crocodilian nests, viewed as microhabitats, are crucial for understanding these impacts and developing comprehensive conservation strategies. We aimed to assess vertebrate species richness, interactions, and visitation frequency at Caiman latirostris nests in Santa Fe, Argentina, across varying levels of habitat disturbance. Over four nesting seasons (2018-2022), we monitored 64 nests in forests, savannas, and marshes through camera traps, resulting in 9,062 trap-nights. A total of 100 species were recorded, including 74 birds, 23 mammals, and 3 reptiles, though some reptiles could not be identified due to nocturnal photos. Species richness correlated with nesting season and habitat type, peaking in the driest season and in forest environments. Despite expectations, no link was found between species richness and anthropization. Of the species observed, 62% interacted with the nests through commensalism, predation, or competition, while the rest were neutral. The Interaction Strength Index (ISI) effectively quantified these interactions, proving to be a reliable indicator of nesting area use and highlighting the role of caiman nests as microhabitats.