Forest plant community changes during 1989-2007 in response to climate warming in the Jura Mountains (France and Switzerland)

Abstract

Question: How strong are climate warming-driven changes within mid-elevation forest communities? Observations of plant community change within temperate mountain forest ecosystems in response to recent warming are scarce in comparison to highelevation alpine and nival ecosystems, perhaps reflecting the confounding influence of forest stand dynamics. Location: Jura Mountains (France and Switzerland). Methods: We assessed changes in plant community composition by surveying 154 Abies alba forest vegetation releve´s (550-1,350 m a.s.l.) in 1989 and 2007. Over this period, temperatures increased while precipitation did not change. Correspondence analysis (CA) and ecological indicator values were used to measure changes in plant community composition. Releve´s in even-and uneven-aged stands were analysed separately to determine the influence of forest stand dynamics. We also analysed changes in species distribution to detect shifts along the elevation gradient by focusing on the lowest, central and highest positions of lowland and mountain species altitudinal ranges. Results: We found significant shifts along the first CA axis, which reflected a change in plant community composition towards a greater frequency of lowland species. Analyses of ecological indicator values indicated increases in temperature and light availability in A. alba stands, particularly in evenaged stands. However, no major changes in overall species distribution were found. Conclusions: The community-level changes are consistent with effects of climate warming and local stand dynamics. Changes in species distribution were small in comparison to observed local temperature increases, perhaps reflecting dispersal limitation, phenotypic plasticity or microclimatic buffering by the tree canopy. Causality cannot rigorously be inferred from such a descriptive study; however, we suggest that recent warming is now driving plant community change in the climatically more moderate mid-elevation forest setting.

Scale sensitivity of the relationship between alpha and gamma diversity along an alpine elevation gradient in central Nepal

“…This is an indication that the dense canopy in the closed-canopy forest may have moderated the process of thermophilisation by maintaining a cooler understorey microclimate (Lenoir et al 2010b;De Frenne et al 2013). In partial agreement with the land-use change hypothesis, there is a significant increase in shade-tolerant trees and bamboo and a decline in the shade-intolerant herbaceous and shrub species.…”

“…climate warming and land-use change, and accord with the major trends of temperature and land-use driven changes across the mountainous areas of the world (e.g., Lenoir et al 2010b;Bai et al 2011;Gottfried et al 2012;De Frenne et al 2013;Rumpf et al 2018). A closer examination of the evident changes, however, reveals rather different trends in response to the two explanatory factors and some of the patterns are potentially confounded due to interactions between climate change and land-use change.…”

Landscape context and long-term tree influences shape the dynamics of forest-meadow ecotones in mountain ecosystems

“…Climate warming has been implicated in compositional changes in other mountain ecosystems of North America and Europe , Lenoir et al 2010), yet we saw little evidence of a direct effect of warming on ground-layer vegetation in this system. If warming was having a direct effect, it likely would not be limited to ecotonal habitats.…”

Vegetation dynamics of beech forests on limestone in central Germany over half a century – effects of climate change, forest management, eutrophication or game browsing?

“…Actual climate-induced vegetation changes have been observed across Europe in terms of an earlier phenology (Dierschke 2000, Fitter & Fitter 2002, Menzel et al 2006, Sparks et al 2009) or species shifts to higher elevations or latitudes (Root et al 2003, Lesica & McCune 2004, Walther et al 2005a, 2005b, 2007, Pauli et al 2007, Lenoir et al 2008, Walther 2010. Records of abundance changes at fine scales in different European forest regions as a result of climate change are however scarce (but see Øk-land et al 2004 andLenoir et al 2010) and mainly restricted to an observed spread of some evergreen species (Carraro et al 2001, Dierschke 2005, Hilker et al 2005, Diekmann 2010) and the early spring-species Allium ursinum (Ahrns & Hofmann 1998, Böhling 2008, Schmidt 2009). Spring geophytes are especially mentioned as being sensitive to an earlier start of the vegetation period, with a lengthening of their growing season and the possibility of reproduction before canopy closure (Menzel et al 2006).…”