Assessing assemblage-wide mammal responses to different types of habitat modification in Amazonian forests

Abstract

Tropical forests are being heavily modified by varying intensities of land use ranging from structural degradation to complete conversion. While ecological responses of vertebrate assemblages to habitat modification are variable, such understanding is critical to appropriate conservation planning of anthropogenic landscapes. We assessed the responses of medium/large-bodied mammal assemblages to the ecological impacts of reduced impact logging, secondary regrowth, and eucalyptus and oil palm plantations in Eastern Brazilian Amazonia. We used within-landscape paired baseline-treatment comparisons to examine the impact of different types of habitat modification in relation to adjacent primary forest. We examined assemblage-wide metrics including the total number of species, number of primary forest species retained in modified habitats, abundance, species composition, and community integrity. We ranked all types of habitat modification along a gradient of assemblage-wide impact intensity, with oil palm and eucalyptus plantations exerting the greatest impact, followed by secondary regrowth, and selectively logging. Selectively-logged and secondary forests did not experience discernible biodiversity loss, except for the total number of primary forest species retained. Secondary forests further experienced pronounced species turnover, with loss of community integrity. Considering the biodiversity retention capacity of anthropogenic habitats, this study reinforces the landscape-scale importance of setting aside large preserved areas.

Socioecological Assessment of Mammal Assemblages in Small Oil-Palm Plantations in a Highly Deforested Region in Mexico

“…As mentioned earlier, most forest remnants in Tabasco are secondary forests. While successional forests do not have the same value for mammal conservation as old-growth forests (Almeida-Maués et al, 2022), in highly deforested regions secondary forests are crucial for mammals, even patches that are early- or mid-successional (Knowlton et al, 2019; Pardo et al, 2018). In our study, the forest remnants that were nearest to most plantations (8 of 11) had a canopy height of only 3-5 m, indicating a relatively early stage of succession, and yet their proximity had a positive effect on mammal diversity in oil-palm plantations.…”

“…This is particularly relevant for animals that have large area requirements, because their conservation must also occur beyond the boundaries of forest remnants (Payán & Boron, 2019). Wildlife conservation in human-modified areas is strongly affected by landscape composition and configuration (Almeida-Maués et al, 2022; Arroyo-Rodríguez et al, 2020), but it also depends on social factors that shape human-wildlife coexistence (Pooley et al, 2021).…”