Scaling between macro‐ to microscale climatic data reveals strong phylogenetic inertia in niche evolution in plethodontid salamanders

Abstract

Macroclimatic niches are indirect and potentially inadequate predictors of the realized environmental conditions that many species experience. Consequently, analyses of niche evolution based on macroclimatic data alone may incompletely represent the evolutionary dynamics of species niches. Yet, understanding how an organisms' climatic (Grinnellian) niche responds to changing macroclimatic conditions is of vital importance for predicting their potential response to global change. In this study, we integrate microclimatic and macroclimatic data across 26 species of plethodontid salamanders to portray the relationship between microclimatic niche evolution in response to changing macroclimate. We demonstrate stronger phylogenetic signal in microclimatic niche variables than at the macroclimatic scale. Even so, we find that the microclimatic niche tracks climatic changes at the macroscale, but with a phylogenetic lag at million-year timescales. We hypothesize that behavioral tracking of the microclimatic niche over space and phenology generates the lag: salamanders preferentially select microclimates similar to their ancestral conditions rather than adapting with changes in physiology. We demonstrate that macroclimatic variables are weak predictors of niche evolution and that incorporating spatial scale into analyses of niche evolution is critical for predicting responses to climate change. K E Y W O R D S :Behavior, climate, ecology, evolution, microclimate, niche evolution . 9 7 9

Is salamander arboreality limited by broad-scale climatic conditions?

“…We acknowledge that climatic data obtained in this fashion are coarse-grained, and that intraspecific variation in both activity patterns and microhabitat use may obscure the association between microhabitat use and the climatic environment. However, recent work on plethodontid climatic envelopes, obtained at both micro- and macro-scales reveals a close association between the two [ 12 ], implying that the climate variables extracted for this study may serve as a first approximation for describing the general patterns and boundaries of microenvironments available to individual salamanders (see Discussion ).…”

Thermal adaptation revisited: How conserved are thermal traits of reptiles and amphibians?

“…For example, plethodontid salamanders from eastern North America exhibit precise behavioral preferences for their ancestral climatic conditions (Farallo et al, 2018). This results in remarkably slow adaptation to climate, incurring a phylogenetic lag (a “slowness” in adaptation) on the scale of millions of years (Farallo et al, 2020). In other words, buffering behaviors can stymie rates of physiological adaptation to novel environmental pressures (e.g., Buckley et al, 2015; Logan et al, 2019; Muñoz & Bodensteiner, 2019).…”

Thermal physiology responds to interannual temperature shifts in a montane horned lizard, Phrynosoma orbiculare

“…For example, increasing temperatures may have resulted in nonrandom survivorship and/or differential reproductive success in this population of P. orbiculare . Previous studies have documented that climate‐induced selection on lizard physiology can be strong, often resulting in rapid phenotypic shifts over short time periods (e.g., Campbell‐Staton et al, 2017; Gilbert & Miles, 2019; Leal & Gunderson, 2012; Logan, Cox, & Calsbeek, 2014), but macroevolutionary studies suggest that climatic adaptation, particularly in upper physiological limits, can be surprisingly sluggish (Bodensteiner et al, 2020; Farallo, Muñoz, Uyeda, & Miles, 2020; Salazar, Castañeda, Londoño, & Muñoz, 2019). Another possibility is that the higher heat tolerance observed in 2019 reflects warmer maternal incubation conditions; warmer embryonic conditions in reptiles can induce overexpression of heat shock proteins that might be retained into adulthood (Gao et al, 2014).…”