Relative performance of ecological niche and occupancy models for predicting invasions by patchily-distributed species

Abstract

Ecological niche models (ENM) have been used with mixed success for predicting the geographic extent of non-native species to aid management and conservation. This approach is problematic for predicting invasions of patchily-distributed species (e.g., pond-breeding amphibians), whose occurrence is often determined by local habitat conditions. Here, we tested the performance of bioclimatic ENM for predicting occurrence (from repeated surveys) of two non-native pond-breeding anurans at 71 wetlands in British Columbia, Canada: permanent pond specialist American bullfrog (Lithobates catesbeianus), and generalist green frog (Lithobates clamitans). For L. catesbeianus, we assessed the risk of invasion beyond the invasion front. We found higher correlation between ENM and occupancy predictions for L. clamitans (r s = 0.58), than for L. catesbeianus (r s = -0.26). L. clamitans occurrence was highest at low elevations and high annual precipitation; in contrast, L. catesbeianus occupancy was predicted by wetland connectivity and distance from a historic introduction site [low at isolated ponds [50 km from the introduction site, and high ([0.8) at all ponds with [10 % water within 500 m]. Conditional on successful dispersal, four sites beyond the L. catesbeianus invasion front surveyed in this study were at high risk of invasion due to high habitat suitability (proportion of area occupied = 0.33; 0.04-0.83, 95 % CI). In conclusion, ENMs may be useful for informing invasion management for climate driven wetland species, but repeated sampling is necessary to predict invasions for habitat-driven wetland species.

Ghid pentru estimarea abundenței și ocupanței animalelor sălbatice

“…Astfel, unul dintre principalele rezultate ale modelelor de ocupanță este procentul de suprafață ocupată (PAO), care exprimă proporția de situri sau suprafețe supravegheate care sunt susceptibile să fie ocupate de o specie. În plus față de utilizarea comună de a estima suprafața ocupată într-o regiune eșantionată, metoda a fost extinsă și pentru a explica și a estima extinderea viitoare a ariei de răspândire, cel mai frecvent în legătură cu speciile invazive (de exemplu, Bled et al, 2011;Murray et al, 2015).…”

Reconstructing biological invasions using public surveys: a new approach to retrospectively assess spatio-temporal changes in invasive spread

“…Further, the models which specified a dispersal hub performed better than the models representing other common pathways such as stowaway and unaided dispersal due to trade and habitat disturbance. The future of the currently unmanaged invasion may depend on new dispersal hubs for the hitherto uninvaded sites (Murray et al 2015) on Baratang, South Andaman, and the Nicobar archipelago and on the recently invaded Little Andaman Island (ca. 2018).…”

Dynamic N‐occupancy models: estimating demographic rates and local abundance from detection‐nondetection data

“…Occupancy is arguably the most widely used measure to document range shifts (e.g., Tingley and Beissinger ), species invasions (e.g., Murray et al. ), and declines in rare species (e.g., global amphibian declines; Adams et al. ).…”

“…Key words: barred owl; demographic rates; dynamic; heterogeneity; latent; N-mixture model; occupancy; species distribution models. intRoduCtion Occupancy monitoring (i.e., presence/absence at a set of sites) can be a cost-effective approach to document changes in the status of species over broad spatial scales. Occupancy is arguably the most widely used measure to document range shifts (e.g., Tingley and Beissinger 2009), species invasions (e.g., Murray et al 2015), and declines in rare species (e.g., global amphibian declines; Adams et al 2013). However, presence/absence monitoring is hindered by imperfect detection (failure to observe a species that is present), which can confound estimates of occupancy.…”