Estimates of Species Richness and Composition Depend on Detection Method in Assemblages of Terrestrial Mammals

Abstract

Detecting rapid changes in mammal composition at large spatial scales requires efficient detection methods. Many studies estimate species composition with a single survey method without asking whether that particular method optimises detection for all occurring species and yields reliable community-level indices. We explore the implications of between-method differences in efficiency, consistency, and sampling effort for the basic characterisation of assemblages of medium to large mammals in a region with three contrasted Mediterranean landscapes. We assessed differences between camera traps, scent stations, scat surveys, and track surveys. Using track surveys, we detected all species present in the regional pool (13) and obtained the most accurate description of local species richness and composition with the lowest sampling effort (16 sampling units and 2 survey sessions at most). Had we chosen camera traps, scent stations, or scat surveys as the only survey method, we would have underestimated species richness (9, 11, and 12 species, respectively) and misrepresented species composition in varying degrees. Preliminary studies of method performance inform whether single or multiple survey methods are needed and eventually which single method might be most appropriate. Without such a formal assessment current practices may produce unreliable and incomplete species inventories, ultimately leading to incorrect conclusions about the impact of human activity on mammal communities.

Geodiversity inclusiveness in biodiversity assessment

“…Geodiversity component terms from the Gray (2013) definition of geodiversity were frequently mentioned in biodiversity assessment literature (Figure 2). Most biodiversity assessments mentioned hydrological components of geodiversity such as rivers, ocean, lakes and springs (Mimouni et al, 2018; Alam et al, 2020; Nneji et al, 2020; Suárez-Tangil and Rodríguez, 2021). For example, Alam et al (2020) assessed fish biodiversity in Korean ‘rivers’ using eDNA metabarcoding approaches.…”

Environmental filtering drives the assembly of mammal communities in a heterogeneous Mediterranean region

“…Specifically, we analyzed the associations between species that operate at approximately the same spatial scale (mean home range size of mammal species was of the same order of magnitude; Appendix S3), we explicitly addressed potential scale issues by specifying spatially structured latent variables in the model, and we improved fit and the explanatory power of the model by replicating mammal surveys over time. This is because higher temporal replication yields a better approximation to the true composition of local communities (Suárez‐Tangil & Rodríguez, 2021b). We conclude that our analysis was able to detect a potential effect of species interactions on community composition and, therefore, that the absence of biotic filtering may be genuine.…”

“…To avoid potential associations between landscape type and the phenology of mammal reproduction or dispersal, the order in which landscapes were sampled in each session was chosen at random. We detected all 13 mammal species but, for the analyses of the present study, we excluded species that were ubiquitous (occupying >95% of the 24 sampling plots) or too scarce (occupying <5% of sampling plots; Suárez‐Tangil & Rodríguez, 2021b). Therefore, we considered nine species, including two ungulates and seven carnivores: wild boar ( Sus scrofa ), red deer ( Cervus elaphus ), common genet ( Genetta genetta ), Egyptian mongoose ( Herpestes ichneumon ), Eurasian badger ( Meles meles ), stone marten ( Martes foina ), Eurasian otter ( Lutra lutra ), European polecat ( Mustela putorius ), and wildcat ( Felis silvestris ).…”

Who is the expert? Evaluating local ecological knowledge for assessing wildlife presence in the Peruvian Amazon

“…Two conventional methods used for monitoring Amazonian wildlife are line transects and camera trapping (Danielsen et al, 2009;Munari, Keller, & Venticinque, 2011;Parry & Peres, 2015)-and opinions differ as to which method is most effective based on cost, sampling effort, and community involvement (Danielsen et al, 2009;Fragoso et al, 2016;Suarez-Tangil & Rodriguez, 2021). In line transects, scientists record wildlife sightings and signs of animals (feces, tracks, fur, etc.)…”