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

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.

Methods
Two data files are included:

1) Includes mean and standard error values for 5 microclimatic conditions collected from 26 species of Plethodontid salamanders, including leaf litter depth, soil moisture, soil temperature, air temperature at 1 meter, and relatvie humidity at 1 meter (and one for logit transformed values of relative humidity).  This data set also include mean and standard error values of temperature and precipitation macroclimatic data extracted from Wordclim Ver. 2.0 (March-July) for both the sampling locations of our study and museum records used by Kozak and Wiens 2010.  

2) Includes direct measurements of 5 microclimatic conditions collected during random habitat surveys including leaf litter depth, soil moisture, soil temperature, air temperature at 1 meter, and relatvie humidity at 1 meter.  These habitat surveys were conducted in conjunction with time constraint surveys for salamander presence.  Each row contains the habitat measures for a single point (e.g., each row is for one single random habitat point and each survey had ~10 points) and identifying information about the survey along with the number of each of 26 species of salamanders found during that entire survey (I will mention it multiple times to be clear, the species counts in each row are for the individuals surveys (group of ~10 rows) and not indivudal habitat points (1 row). This is explained in more detail in the useage notes and in comments on the excel file itself. 

All excel files include additional comments to help explain any aspects of the data set that may be confusing.