Ecological and evolutionary processes at expanding range margins

Abstract

Many animals are regarded as relatively sedentary and specialized in marginal parts of their geographical distributions. They are expected to be slow at colonizing new habitats. Despite this, the cool margins of many species' distributions have expanded rapidly in association with recent climate warming. We examined four insect species that have expanded their geographical ranges in Britain over the past 20 years. Here we report that two butterfly species have increased the variety of habitat types that they can colonize, and that two bush cricket species show increased fractions of longer-winged (dispersive) individuals in recently founded populations. Both ecological and evolutionary processes are probably responsible for these changes. Increased habitat breadth and dispersal tendencies have resulted in about 3- to 15-fold increases in expansion rates, allowing these insects to cross habitat disjunctions that would have represented major or complete barriers to dispersal before the expansions started. The emergence of dispersive phenotypes will increase the speed at which species invade new environments, and probably underlies the responses of many species to both past and future climate change.

Capturing genetic variation in crop wild relatives: An evolutionary approach

“…relatively large‐sized populations, in which local adaptation is generally more common than in smaller ones (Leimu & Fischer, 2008); and 3.) the range margins of a CWR, where the direction, magnitude and tempo of natural selection and adaptation may differ largely from that of the range interior (Hill, Griffiths, & Thomas, 2011; Thomas, Bodsworth, Wilson, & Simmons, 2001). …”

Predicting the future of forests in the Mediterranean under climate change, with niche- and process-based models: CO2 matters!

“…Adaptive modes could be highly important for predicting future species responses to climate change. The models presented here assume nonsignificant evolutionary and/or ecological change in a species in response to changing environmental conditions through time [thus ignoring rapid in situ adaptation (Thomas et al, 2001), and existing adaptation of populations to local conditions (Hampe, 2004), etc.]. Evidence suggests that species adaption has occurred for many species (Pearman et al, 2008), implying a questionable ability of models to project species responses to potential future climates.…”

Accounting for habitat when considering climate: has the niche of the Adonis blue butterfly changed in the UK?

“…The role of climate change in the range expansion of the butterfly Hesperia comma in the UK has been extensively studied (Davies et al 2005;Thomas et al 2001;Wilson et al 2009Wilson et al , 2010. Davies et al (2006) show that a key factor enabling this expansion was a widening of H. comma's realized larval niche under warmer air temperatures.…”

“…Thermal constraints at higher latitudes can be relaxed, broadening the amount of habitat available to a species by enabling its larvae to occupy cooler aspects and slopes, and to exploit food plants in later successional stages; this in turn may facilitate range expansion and recovery in species that have undergone declines (Oliver et al 2012;Thomas et al 2001). The role of climate change in the range expansion of the butterfly Hesperia comma in the UK has been extensively studied (Davies et al 2005;Thomas et al 2001;Wilson et al 2009Wilson et al , 2010.…”

“…Global warming is an equally well-documented driver of change in insects, affecting phenology, voltinism, niche breadth, population stability and density, and geographic ranges (Altermatt 2010;Davies et al 2006;Hill et al 2002;Oliver et al 2012;Parmesan 2006;Parmesan et al 1999;Roy et al 2001;Roy and Sparks 2000;Thomas et al 2001).…”