Environmental niche models for riverine desert fishes and their similarity according to phylogeny and functionality

Abstract

Citation: Whitney, J. E., J. B. Whittier, and C. P. Paukert. 2017. Environmental niche models for riverine desert fishes and their similarity according to phylogeny and functionality. Ecosphere 8(1):e01658. 10. 1002/ecs2.1658 Abstract. Environmental filtering and competitive exclusion are hypotheses frequently invoked in explaining species' environmental niches (i.e., geographic distributions). A key assumption in both hypotheses is that the functional niche (i.e., species traits) governs the environmental niche, but few studies have rigorously evaluated this assumption. Furthermore, phylogeny could be associated with these hypotheses if it is predictive of functional niche similarity via phylogenetic signal or convergent evolution, or of environmental niche similarity through phylogenetic attraction or repulsion. The objectives of this study were to investigate relationships between environmental niches, functional niches, and phylogenies of fishes of the Upper (UCRB) and Lower (LCRB) Colorado River Basins of southwestern North America. We predicted that functionally similar species would have similar environmental niches (i.e., environmental filtering) and that closely related species would be functionally similar (i.e., phylogenetic signal) and possess similar environmental niches (i.e., phylogenetic attraction). Environmental niches were quantified using environmental niche modeling, and functional similarity was determined using functional trait data. Nonnatives in the UCRB provided the only support for environmental filtering, which resulted from several warmwater nonnatives having dam number as a common predictor of their distributions, whereas several cool-and coldwater nonnatives shared mean annual air temperature as an important distributional predictor. Phylogenetic signal was supported for both natives and nonnatives in both basins. Lastly, phylogenetic attraction was only supported for native fishes in the LCRB and for nonnative fishes in the UCRB. Our results indicated that functional similarity was heavily influenced by evolutionary history, but that phylogenetic relationships and functional traits may not always predict the environmental distribution of species. However, the similarity of environmental niches among warmwater centrarchids, ictalurids, fundulids, and poeciliids in the UCRB indicated that dam removals could influence the distribution of these nonnatives simultaneously, thus providing greater conservation benefits. However, this same management strategy would have more limited effects on nonnative salmonids, catostomids, and percids with colder temperature preferences, thus necessitating other management strategies to control these species.

Quantifying isolation-by-resistance and connectivity in dendritic ecological networks

“…These altered conditions may also change the distribution and suitability of low-flow refugia, serving in turn to extirpate peripheral populations (Schlosser 1995, Bezzerides and Bestgen 2002, Magoulick and Kobza 2003). Altered conditions also promote the establishment of non-native species (Gido and Propst 1999, Whitney et al 2017, Dibble et al 2020), which may in turn elevate predation rates and promote competition (Marsh and Douglas 1997, Seegert et al 2014). Predation pressure by resident fishes also constrains the invasion success of introduced SPD (Harvey et al 2004), thus suggesting a potential role for non-natives in promoting ‘biotic’ resistance.…”