Management-driven evolution in a domesticated ecosystem

Abstract

Millennia of human land-use have resulted in the widespread occurrence of what have been coined ‘domesticated ecosystems’. The anthropogenic imprints on diversity, composition, structure and functioning of such systems are well documented. However, evolutionary consequences of human activities in these ecosystems are enigmatic. Calluna vulgaris (L.) is a keystone species of coastal heathlands in northwest Europe, an ancient semi-natural landscape of considerable conservation interest. Like many species from naturally fire-prone ecosystems, Calluna shows smoke-adapted germination, but it is unclear whether this trait arose prior to the development of these semi-natural landscapes or is an evolutionary response to the anthropogenic fire regime. We show that smoke-induced germination in Calluna is found in populations from traditionally burnt coastal heathlands but is lacking in naturally occurring populations from other habitats with infrequent natural fires. Our study thus demonstrates evolutionary imprints of human land-use in semi-natural ecosystems. Evolutionary consequences of historic anthropogenic impacts on wildlife have been understudied, but understanding these consequences is necessary for informed conservation and ecosystem management.

Fire and plant diversity at the global scale

“…There are at least two (not mutually exclusive) mechanisms by which fire may drive plant diversity at the scale and grain considered here. The first is a selective process, as there is both micro‐ and macroevolutionary evidence suggesting that fire regime can drive population divergence and diversification (Bytebier et al, ; Crisp et al, ; Gómez‐González et al, ; He et al, ; Hernández‐Serrano et al, ; Pausas, ; Pausas et al, ; Vandvik et al, ). The second process suggests that fire generates landscape mosaics and thus more habitat types and more niches likely to be filled by different species (e.g., Bird, Bird, Codding, Parker, & Jones, ; Bond & Keeley, ; Cohn et al, ; Kelly et al, ; Parr & Brockett, ); in this sense, fire would generate the biotic heterogeneity that drives diversity (Stein et al, ), as proposed by the ‘pyrodiversity begets diversity’ hypothesis (Bowman et al, ; Martin & Sapsis, ).…”

“…For instance, fire is a disturbance with a very long evolutionary history (Pausas & Keeley, ), and recurrent fires have selected for specific plant persistence traits (Keeley, Pausas, Rundel, Bond, & Bradstock, ). Indeed, there is microevolutionary evidence suggesting that fire can drive phenotypic and genetic divergence within species (Gómez‐González, Torres‐Díaz, Bustos‐Schindler, & Gianoli, ; Hernández‐Serrano, Verdú, González‐Martínez, & Pausas, ; Pausas ; Pausas, Alessio, Moreira, & Corcobado, ; Vandvik et al, ). Likewise, macroevolutionary studies show the importance of fire in the diversification of some plant lineages (Bytebier, Antonelli, Bellstedt, & Linder, ; Crisp, Burrows, Cook, Thornhill, & Bowman, ; He, Lamont, & Downes, ; He, Pausas, Belcher, Schwilk, & Lamont, ).…”

Biological and geophysical feedbacks with fire in the Earth system

“…They also have a stronger cooling effect (negative radiative forcing) due to the larger change in surface properties after fire (Rogers et al 2015). The climates of these two regions are too similar to explain these differences (Rogers et al 2015, de Groot et al 2013) and there is evidence that plant traits (box 2) of the dominant tree species of each region are The BUI is a measure of the moisture content of the litter fuels (duff) and is a function of temperature and precipitation (Van Wagner and Pickett 1985). key drivers of the fire dynamics.…”

Marginal Calluna populations are more resistant to climate change, but not under high-nitrogen loads

“…These nutrient-poor (mostly N-limited) environments have a high conservation value (e.g. Alonso and Hartley 1998;NATURA 2000 Habitat Directive;Borchard et al 2014;Vandvik et al 2014), because they host a huge proportion of the biodiversity typical of open acidic sites and are amongst the oldest cultural landscapes in Europe (Gimingham 1972). The distribution range of Calluna heathlands is characterised by a humid climate, mild temperatures and moderate summer drought events (Loidi et al 2010).…”

“…Heathland ecosystems with the dominant ericaceous dwarf shrub Calluna vulgaris (L.) Hull (henceforth referred to as Calluna) are widely distributed over Western Europe (Gimingham 1972;Vandvik et al 2014). These nutrient-poor (mostly N-limited) environments have a high conservation value (e.g.…”