Mountains and traits: environmental heterogeneity and mammal assemblages along an elevational gradient in the Northern Andes

ABSTRACT

We assessed the variation of both composition and functional diversity of mammals along an elevation gradient (1600–3600 masl) at the Tabaconas Namballe National Sanctuary (TNNS) in northern Peru. Using a camera-trap design (85 stations, 8,825 camera days, ~ 317 km²), we recorded a total of 33 mammalian species during the dry season of 2016. Species-specific effects of environmental covariates based on multi-species occupancy modeling showed that only elevation had a statistically significant effect on occupancy. Also, a principal coordinate analysis and a distance-based redundancy analysis suggested that the variation in species composition is mainly explained by elevation, and moderately by both the normalized difference vegetation index (NDVI) and the distance to roads. The highlands appear to be dominated by a reduced assembly of species consisting of the montane guinea pig, the Andean fox, and the northern pudu. Functional diversity decreased with elevation, providing evidence that lowland and highland communities are functionally dissimilar. Moreover, land-use is changing rapidly in the areas surrounding the TNNS, suggesting that increased connectivity at the two extremes of the elevational gradient (the highlands and the lowlands) will ensure the long-term viability of terrestrial mammalian populations and, thus, the ecological processes in which they are involved.

KEYWORDS:

• Functional diversity
• elevational gradient
• mammals
• Northern Andes
• Peru
• species sorting

Acknowledgments

We especially thank Douglas Cotrina, and the park rangers Evelio Lozada, Segundo Neyra, Jesus Aponte, Leoncio Ocupa, Marco Tenorio, Alis Hoower Lozada, Alexander Campos, César Caruajulca, Alexander Ramírez, and Ronal Campos for their excellent field assistance. We also thank Carina Huaman for her invaluable help with logistics, and Luis Hiyo, Hiromi Yagui, and Fabiola La Rosa for their support in fieldwork. We are grateful to Hiromi Yagui for reviewing previous versions of the manuscript. We recognize the assistance of Jorge Rivero and Johanna Bindels in camera trap data processing. Pamela Pastor provided support with the GIS. Melinda Modrell and Aaron Skinner revised the English version of the manuscript. Funds from WWF-Peru supported this study. We want to thank the administration office of the Tabaconas Namballe National Sanctuary and the National Service of Natural Protected Areas (SERNANP).

Disclosure statement

No potential conflict of interest was reported by the authors. Its publication has been approved by the authors.

Supplementary material

Supplemental data for this article can be accessed here.

Additional information

Funding

This work was supported by the resources of WWF-Peru.