Frequency, not relative abundance, of temperate tree species varies along climate gradients in eastern North America

Abstract

Abstract. There have been many attempts to model the impacts of climate change on the distributions of temperate tree species, but empirical analyses of the effects of climate on the distribution and abundance of tree species have lagged far behind the models. Here, we used forest inventory data to characterize variation in adult tree abundance along climate gradients for the 24 most common tree species in the northeastern United States. The two components of our measure of species abundance-local frequency vs. relative abundance-showed dramatically different patterns of variation along gradients of mean annual temperature and precipitation. Local frequency (i.e., the percentage of plots in a given climate in which a species occurred) varied strongly for all 24 species, particularly as a function of temperature. Relative abundance when present in a plot, on the other hand, was effectively constant for most species right up to their estimated climatic range limits. Although the range limits for both temperature and precipitation were quite broad for all of the species, the range of climates within which a species was common (i.e., high frequency) was much narrower. Because frequency in sites within a given climate shows a strong sensitivity to temperature, at least, this suggests that the processes determining canopy tree recruitment on new sites also vary strongly with climate.

Demography linked to climate change projections in an ecoregional case study: integrating forecasts and field data

“…v www.esajournals.org (Canham and Thomas 2010). These impacts on recruitment amplify the importance of managing for multi-age stands (McCreary 2009).…”

Mass invasion of non-nativeElodea canadensisMichx. in a large, clear-water, species-rich Norwegian lake – impact on macrophyte biodiversity

“…Individual photographs within each such category were treated as replicate quadrats. Lake-wide depth distribution for total vegetation and selected macrophyte species was estimated by pooling all quadrat data from the seven sampling stations into 0.25-m depth intervals, producing smoothed line curves of depthbased average %cover ¡ standard error, which expressed (relative) abundance (e.g., Canham and Thomas, 2010;Bonar et al, 2011). Two-factor analysis (such as two-way analysis of variances (ANOVAs)) could not be performed because of uneven sample size (e.g., Zar, 2009).…”

Shifting with climate? Evidence for recent changes in tree species distribution at high latitudes

“…Eleven species (Abies balsamea, Acer rubrum, Acer saccharum, Betula alleghaniensis, Betula papyrifera, Fagus grandifolia, Ostrya virginiana, Picea glauca, Picea mariana, Populus tremuloides, Thuja occidentalis) with the northernmost part of their range within the study area (under 538N) and with at least 50 occurrences in each of S 1 , S 2 , T 1 and T 2 were selected (Little 1971, Soper and Heimburger 1990, Flora of North America Editorial Committee 1993, Farrar 1995. Only presence/absence data were used because climate predicts frequency of occurrence at different latitudes much better than it predicts local abundance in a plot (Canham andThomas 2010, Chambers et al 2013). Therefore change of occupancy of a plot (presence/absence) can provide a stronger signal for range shift than change in tree abundance in that plot.…”

“…For trees, climate variables are strong predictors of site occupancy (Canham and Thomas 2010), correlate with recruitment patterns (Elliott 2012), and determine northern range limits (Morin et al 2007). Northward shifts of species optimal climate conditions of hundreds of kilometers are therefore projected for this century in the northern temperate and boreal forests (McKenney et al 2011, Chambers et al 2013, Berteaux et al 2014, Périé et al 2014.…”