Climate vs. Soil Factors in Local Adaptation of Two Common Plant Species

Abstract

Evolutionary theory suggests that divergent natural selection in heterogeneous environments can result in locally adapted plant genotypes. To understand local adaptation it is important to study the ecological factors responsible for divergent selection. At a continental scale, variation in climate can be important while at a local scale soil properties could also play a role. We designed an experiment aimed to disentangle the role of climate and (abiotic and biotic) soil properties in local adaptation of two common plant species. A grass (Holcus lanatus) and a legume (Lotus corniculatus), as well as their local soils, were reciprocally transplanted between three sites across an Atlantic-Continental gradient in Europe and grown in common gardens in either their home soil or foreign soils. Growth and reproductive traits were measured over two growing seasons. In both species, we found significant environmental and genetic effects on most of the growth and reproductive traits and a significant interaction between the two environmental effects of soil and climate. The grass species showed significant home site advantage in most of the fitness components, which indicated adaptation to climate. We found no indication that the grass was adapted to local soil conditions. The legume showed a significant home soil advantage for number of fruits only and thus a weak indication of adaptation to soil and no adaptation to climate. Our results show that the importance of climate and soil factors as drivers of local adaptation is species-dependent. This could be related to differences in interactions between plant species and soil biota.

Aboveground environment type, soil nutrient content and arbuscular mycorrhizal fungi explain establishment success of Centaurea jacea on ex-arable land and in late-successional grasslands

“…The higher seedling survival on soil from restoration sites may be due to a lower abundance of pathogenic fungi in soils that were used for arable practice and where no C. jacea has grown for many years, and the negative feedback may be less strong in those soils than in soils from late-successional grasslands, where the soil microbial community may have been cultured by the presence of C. jacea. (Klironomos 2002;De Deyn et al 2003;Kardol et al 2006;Bezemer et al 2006;Macel et al 2007). However, various other groups of soil organisms can also affect seedling survival, including root feeding insects and nematodes (Brown and Gange 1989;Olff et al 2000;De Deyn et al 2003).…”

A question of origin: Where and how to collect seed for ecological restoration

“…Becker, Colling, Dostal, Jakobsson, & Matthies 2006;Etterson 2004;Joshi et al 2001). Climate has been identified as the main driver of selection at such large scales but other environmental factors that show large-scale patterns may also act as diverging selective forces (Etterson 2004;Joshi et al 2001;Macel et al 2007;Santamaria et al 2003). In addition, the probability of gene flow and genetic exchange between populations decreases with distance enhancing genetic differentiation even if environmental conditions and selective forces are very similar (Epperson 2003).…”

Adaptation in Natural Microbial Populations

“…Indeed, a reciprocal transplant study comparing local adaptation of grass species (which 20 are not directly affected by nitrogen-fixing bacteria) and legumes (which are directly affected by nitrogen-fixing bacteria) found that grass species were primarily locally adapted to climatic conditions, whereas legumes performed much better when grown in their local soil (Macel et al 2007). Similarly, a study of bacterial local adaptation to soil from across an old growth forest demonstrated a decrease in fitness as bacteria were 25 transplanted away from their home site at a rate of about six percent per meter; a rate which is similar in scale to plant local adaptation (Belotte et al 2003).…”