Long-term resistance to simulated climate change in an infertile grassland

Abstract

Climate shifts over this century are widely expected to alter the structure and functioning of temperate plant communities. However, long-term climate experiments in natural vegetation are rare and largely confined to systems with the capacity for rapid compositional change. In unproductive, grazed grassland at Buxton in northern England (U.K.), one of the longest running experimental manipulations of temperature and rainfall reveals vegetation highly resistant to climate shifts maintained over 13 yr. Here we document this resistance in the form of: (i) constancy in the relative abundance of growth forms and maintained dominance by longlived, slow-growing grasses, sedges, and small forbs; (ii) immediate but minor shifts in the abundance of several species that have remained stable over the course of the experiment; (iii) no change in productivity in response to climate treatments with the exception of reduction from chronic summer drought; and (iv) only minor species losses in response to drought and winter heating. Overall, compositional changes induced by 13-yr exposure to climate regime change were less than short-term fluctuations in species abundances driven by interannual climate fluctuations. The lack of progressive compositional change, coupled with the long-term historical persistence of unproductive grasslands in northern England, suggests the community at Buxton possesses a stabilizing capacity that leads to long-term persistence of dominant species. Unproductive ecosystems provide a refuge for many threatened plants and animals and perform a diversity of ecosystem services. Our results support the view that changing land use and overexploitation rather than climate change per se constitute the primary threats to these fragile ecosystems.calcareous grassland ͉ climate manipulation ͉ global change ͉ multivariate analysis ͉ vegetation

Rapid genetic divergence in response to 15 years of simulated climate change

“…These former abundance data are point quadrat records drawn from Grime et al . (2008; Fig. S1); population abundance and population density are correlated in this system (see results).…”

“…BCCIL maintains some of the longest‐running multifactorial climate manipulations in the world. Community composition has remained relatively stable in all experimental treatments (Grime et al ., 2000, 2008). Such stability is rare; the majority of experimental climate manipulation studies report rapid community and ecosystem responses (e.g.…”

“…Harte & Shaw, 1995; Grime et al ., 2000; Zavaleta et al ., 2003; Evans et al ., 2011). Genetic adaptation to climatic selection has been hypothesized as one potential mechanism supporting the apparent resistance of this grassland community to long‐term climate manipulations (Grime et al ., 2008). Genetic variation in phenotype has been documented at fine spatial scales (< 10 m) in several of the species that are common at BCCIL, and this diversity can influence plant community structure (Booth & Grime, 2003; Fridley et al ., 2007; Whitlock et al ., 2007, 2010; Bilton et al ., 2010).…”

Reproductive system of a mixed-mating plant responds to climate perturbation by increased selfing

“…Finally, there may be response lags in some plant populations, such that the direct effects of climate change are not immediately apparent [7,9]. For example, various forms of compensatory buffering may provide short-term resiliency in growth and reproduction, but have longer-term costs through the draining of carbohydrate reserves or increased inbreeding depression from selfing [11,20].…”

“…Persistent herbivory, for example, may prevent rapid changes in community composition by suppressing species that might otherwise thrive in the new climate [7]. Pollen limitation, whether associated with climate change or non-climatic factors such as habitat loss, can potentially hamper how plants respond to perturbations by limiting pollen flow [7,[16][17][18].…”