Effects of occupancy estimation on abundance–occupancy relationships

Abstract

Abundance–occupancy relationships predict that species that occupy more sites are also more locally abundant, where occupancy is usually estimated following the assumption that species can occupy all sampled sites. Here we use the National Ecological Observatory Network small-mammal data to assess whether this assumption affects abundance–occupancy relationships. We estimated occupancy considering all sampled sites (traditional occupancy) and only the sites found within the species geographic range (spatial occupancy) and realized environmental niche (environmental occupancy). We found that when occupancy was estimated considering only sites possible for the species to colonize (spatial and environmental occupancy) weaker abundance–occupancy relationships were observed. This shows that the assumption that the species can occupy all sampled sites directly affects the assessment of abundance–occupancy relationships. Estimating occupancy considering only sites that are possible for the species to colonize will consequently lead to a more robust assessment of abundance–occupancy relationships.

The global distribution of angiosperm genome size is shaped by climate

“…As the relative importance of natural selection versus random genetic drift depends on population size, the mutational-hazard hypothesis (MHH) posits that genome growth via TEs occurs more readily in smaller populations, where genetic drift is more prominent than natural selection (i.e., species with smaller effective population sizes will have larger genomes; Lynch & Conery, 2003; Lynch, 2007). The relative importance of natural selection and genetic drift also appears to hold for species range size in both plants and animals (Corbett-Detig et al ., 2015), likely because of the positive abundance-occupation relationship (Gaston et al ., 2002) where species with larger populations tend to have large distributional ranges (e.g., Brown, 1984; Johnson, 1998; Gaston, 2003; Webb et al ., 2012; Drovetski et al ., 2014; Spence et al ., 2021; Guo et al ., 2022; Ten Caten et al ., 2022).…”

The global distribution of angiosperm genome size is shaped by climate

“…The relative importance of natural selection and genetic drift also appears to hold for species range size in both plants and animals (Corbett‐Detig et al ., 2015), likely because of the positive abundance‐occupation relationship (Gaston et al ., 2002) where species with larger populations tend to have large distributional ranges (e.g. Brown, 1984; Johnson, 1998; Gaston, 2003; Webb et al ., 2012; Drovetski et al ., 2014; Spence et al ., 2021; Guo et al ., 2022; Ten Caten et al ., 2022).…”