All that changes is not shift: methodological choices influence niche shift detection in freshwater invasive species

Abstract

Species distribution models are often used to predict the potential distributions of invasive species outside their native ranges and rely on the assumption of realized niche conservatism. Analyses observed that freshwater invasive species often show high degrees of niche expansion, suggesting limited reliability of species distribution models. However, observed niche shifts can arise because of both actual niche shifts, determined by biological factors, and apparent shifts, due to methodological issues. We compared metrics of niche dynamics calculated using different sets of variables to identify factors that could influence the rate of niche shifts. We collected presenceonly data for 40 freshwater invasive animal species, then measured niche shift dynamics using 14 different combinations of environmental variables. Shifts were assessed measuring niche overlap, expansion and unfilling, and testing for niche conservatism. We then built generalized linear mixed models relating niche shifts to methodological choices and biological features. Our results showed that methodological choices strongly affected all the considered niche dynamics metrics, while the effects of biological features were less prominent. Moreover, different niche dynamic measures sometimes provided contradictory assessments of niche conservatism. Niche analyses are powerful tools to predict areas at risk of invasion, but inappropriate methodological choices can lead to apparent niche shifts, questioning niche model reliability and biological interpretation. The high rate of niche expansion observed in freshwater invasive species highlights the importance of delineating objective criteria to determine the set of variables to be used in niche dynamic assessments.

Modeling the pest‐pathogen threats in a warming world for the red turpentine beetle (Dendroctonus valens) and its symbiotic fungus (Leptographium procerum)

“…Despite deviations, noting such discrepancies helps a better understanding of the changes in environmental preferences displayed by invasive species within the confines of their ecological niche following invasion. Therefore, given the considerable impact of methodological choices on the conclusions drawn, it is advisable to employ a combination of diverse methods to explore the ecological niche of invasive species 20,64 . Furthermore, reciprocal projections from the NA and CM models yielded consistent results regarding the invasion history of D. valens as observed in genetic analyses 65,66 .…”

“…Therefore, we should interpret the final conclusions from multiple methods with caution. In future research, the use of physiological and genomic data through experimental approaches will enable more comprehensive assessments of the ongoing threats posed by invasive species 64 . Regarding modeling for D. valens and L. procerum , we utilized the correlative model MaxEnt to predict their potential distributions in both historical and future scenarios.…”

Analysis of potential niche shifts in alien pairs of mantis species (Insecta, Mantodea) with comments on the current taxonomic and ecological knowledge

“…The last point also explains the importance of precipitation variables such as BIO13 for this species in the intra-species analyses. Thus, a low D overlap and high unfilling may imply that Tenodera species are constrained by abiotic and movement factors in the United States, and the high expansion may be explained by a relatively small native range (Bates et al 2020) or by the chosen variables (see Lo Parrino et al 2023). However, it is also recognized that T. sinensis shifted its maturation period over the years in the United States, showing a degree of biological plasticity potentially triggered by temperature changes, which may also lead to a range expansion in this species (Hurd et al 2020).…”

“…I considered E as significant if its value was > 10%. Unfilling (U) followed the definition of Petitpierre et al (2012), and I considered it significant if it was > 10%, as done with E in previous studies (Petitpierre et al 2012, Lo Parrino et al 2023). To evaluate if similarities/differences were caused by random effects, I ran niche equivalency tests following Bates et al (2020).…”

“…At the same time, methods for analyzing niche shifts may also be biased by several factors. For example, the chosen metric thresholds and variables have been shown to hugely influence results and interpretations (Bates and Bertelsmeier 2021;Lo Parrino et al 2023). It is also important to note that incomplete ecological niches may be suitable for one population of a non-native species to colonize while excluding a second, closely related population (Liu et al 2020).…”