Rapid latitudinal range expansion at cold limits unlikely for temperate understory forest plants

Abstract

Citation: Beauregard, F., and S. de Blois. 2016. Rapid latitudinal range expansion at cold limits unlikely for temperate understory forest plants. Ecosphere 7(11):e01549. 10.1002Ecosphere 7(11):e01549. 10. /ecs2.1549 Abstract. We ask whether climate warming will be likely to trigger rapid northward range expansion for understory plants in the northeastern forests of North America at the temperate-boreal forest ecotone. We answer this question through a detailed analysis of contemporary occupancy patterns at cold range edges and by looking for patterns consistent with climate or other environmental (e.g., edaphic) limitations. We first identify each species' realized growing degree-day niche to sample zones central, at the tail, or beyond the edge of this niche. We model habitat suitability, based on 11 nonclimate variables, for each species, and compare the availability of, and occupancy on, suitable sites across zones, with the assumption that a limiting climate is likely to result in decreased occupancy or abundance on otherwise suitable sites toward the range limit. We also check for evidence of shifts to warm microclimate conditions at the range limit as a potential indication of climate limitations. Based on our habitat models, we find that the availability of suitable sites declines across these three zones for most species, while occupancy increases on suitable sites at range edge, and abundance does not vary significantly. Some species shifted to sites with warm microclimate conditions; of these, several also declined in abundance suggesting climate limitations. We conclude, however, that for most species studied, suitable site availability appears to determine the northern edges of distribution and, consequently, warming may not necessarily lead to near-term range expansions.

Dominant forest tree species are potentially vulnerable to climate change over large portions of their range even at high latitudes

“…What remains unclear, however, is the extent to which climate mainly determines species range boundaries and whether current distribution patterns really capture the physiological limits of species ( Brown & Vellend , 2014 ; García-Valdés et al , 2015 ; Nowacki & Abrams , 2015 ; Paul, Bergeron & Tremblay , 2014 ). The availability of suitable conditions other than climate ( Beauregard & De Blois , in press ), postglacial dispersal limitations, or competition can all contribute to species not filling their available climatic niche ( Sinclair, White & Newell , 2010 ). Coupling physiological models or trait information with correlative range models can help refine projections ( Iverson et al , 2011 ; Talluto et al , 2016 ), providing that physiological models capture species responses outside the range of conditions represented by species presence-absence data.…”

Climate limitation at the cold edge: contrasting perspectives from species distribution modelling and a transplant experiment

“…For example, Normand et al (2009) found that half of the investigated vascular plants were limited by temperature at their latitudinal and altitudinal upper range margin. Beauregard and De Blois (2016) reported that some investigated plant species at their cold edge shifted to sites with warmer microclimate conditions. Still, we are cautious to infer climate limitation from the correlative SDMs, since many environmental variables as well as land use history in our study area change in parallel with climate (Ashcroft et al 2011).…”

“…Different forest types and landforms also create considerable near-ground microclimate variation (Suggitt et al 2011, De Frenne and Verheyen 2015, Greiser et al 2018. Due to microclimatic heterogeneity one would expect a patchy advancing front tracking global warming (Hylander et al 2015), where species at their cold edge would occupy sites with relatively warmer microclimates (Beauregard and De Blois 2016). Thus, largescale biogeographical predictions at range margins, based on coarse-gridded climate data, might miss that some local populations perform well (Vilà-Cabrera et al 2019).…”

Global warming will affect the maximum potential abundance of boreal plant species

“…In order to take advantage of best practices for conservation and ecosystem management, the effects of warming on vegetation may need to be forecasted. This is a challenging objective given the intrinsic complexity of species environmental responses and between‐species positive and negative interactions, and only some studies have attempted to predict latitudinal shifts of northern vegetation under future global warming scenarios to date (but see Gignac et al , Bakkenes et al , Beauregard and de Blois ).…”

“…Thus, the response of species to temperature may vary among regions with different combinations of environmental variables (Peñuelas et al ), land management (García‐Valdés et al , Tonteri et al ) and biotic interactions (Shi et al ). This includes locations where temperature may be the factor limiting abundance, as well as locations where other factors may oust temperature from limiting species abundance (Gibson‐Reinemer and Rahel , Beauregard and de Blois ). Liebig's law of the minimum predicts that only one of these environmental factors will be the active limiting constraint of species abundance at any given point in time and space (Hiddink and Kaiser ).…”