Functional diversity of North American broad-leaved trees is codetermined by past and current environmental factors

TY - JOUR

T1 - Functional diversity of North American broad-leaved trees is codetermined by past and current environmental factors

AU - Ordonez Gloria, Alejandro

AU - Svenning, J.-C.

PY - 2016

Y1 - 2016

N2 - Modern and historical climate are known to codetermine broad-scale species richness and composition patterns in temperate regions. Nonetheless, is poorly understood the extent to which these effects individually or in combination determine functional diversity, many studies have simply assumed equilibrium between current climate and functional diversity. We estimated functional richness (F Rich) and dispersion (F Disp) of North American broad-leaved trees by combining distribution and trait information. Then, we determined if contemporary water-energy availability, current topographic variability, historical climatic stability, and lagged immigration from glacial refugia codetermined the functional diversity of North American broad-leaved trees. We did this by assessing the directionality, magnitude, and relative importance of various contemporary and historical environmental factors know to affect species diversity. Contrasts were performed across all North America (Mexico, United States, and Canada), and areas within this region that were glaciated or icefree during the Last Glacial Maximum (∼21 000 yr ago). F Ridh and F Disp showed distinct geographic patterns that are strongly associated with both contemporary environmental conditions and glacialinterglacial climate change. Model averaged regression coefficients and AIC-based variable relative importance estimates show that contemporary productivity (F Rich-w AIC: 1.0; F Disp-w AIC: 1.0), annual precipitation (F Rich-w AIC: 0.81; F Disp-w AIC: 1.0), and accessibility to glacial refugia (F Rich-w AIC: 0.92; F Disp-w AIC: 1.0) have the strongest associations to F Rich and F Disp. Furthermore, the association of functional diversity with topographic heterogeneity showed steeper slopes in ice-free regions. These findings suggest that, contrary to the expectation climate-diversity equilibrium, functional diversity of North America broad-leaved trees is codetermined by current climate and lagged immigration from glacial refugia.

AB - Modern and historical climate are known to codetermine broad-scale species richness and composition patterns in temperate regions. Nonetheless, is poorly understood the extent to which these effects individually or in combination determine functional diversity, many studies have simply assumed equilibrium between current climate and functional diversity. We estimated functional richness (F Rich) and dispersion (F Disp) of North American broad-leaved trees by combining distribution and trait information. Then, we determined if contemporary water-energy availability, current topographic variability, historical climatic stability, and lagged immigration from glacial refugia codetermined the functional diversity of North American broad-leaved trees. We did this by assessing the directionality, magnitude, and relative importance of various contemporary and historical environmental factors know to affect species diversity. Contrasts were performed across all North America (Mexico, United States, and Canada), and areas within this region that were glaciated or icefree during the Last Glacial Maximum (∼21 000 yr ago). F Ridh and F Disp showed distinct geographic patterns that are strongly associated with both contemporary environmental conditions and glacialinterglacial climate change. Model averaged regression coefficients and AIC-based variable relative importance estimates show that contemporary productivity (F Rich-w AIC: 1.0; F Disp-w AIC: 1.0), annual precipitation (F Rich-w AIC: 0.81; F Disp-w AIC: 1.0), and accessibility to glacial refugia (F Rich-w AIC: 0.92; F Disp-w AIC: 1.0) have the strongest associations to F Rich and F Disp. Furthermore, the association of functional diversity with topographic heterogeneity showed steeper slopes in ice-free regions. These findings suggest that, contrary to the expectation climate-diversity equilibrium, functional diversity of North America broad-leaved trees is codetermined by current climate and lagged immigration from glacial refugia.

KW - climate velocity

KW - ecosystem function

KW - functional traits

KW - glacial–interglacial climate change

KW - history

KW - species richness

UR - http://www.scopus.com/inward/record.url?scp=84962523985&partnerID=8YFLogxK

U2 - 10.1002/ecs2.1237

DO - 10.1002/ecs2.1237

M3 - Journal article

SN - 2150-8925

VL - 7

JO - Ecosphere (Washington, D.C.)

JF - Ecosphere (Washington, D.C.)

IS - 2

M1 - 1237

ER -