Encroachment of shrubs into subalpine grasslands in the Pyrenees modifies the structure of soil fungal communities and soil properties

Belowground impacts of alpine woody encroachment are determined by plant traits, local climate, and soil conditions

“…Woody plant encroachment can also indirectly influence soil microbes through changes in the abiotic soil environment (Collins, Carey, Aronson, Kopp, & Diez, 2016; Grau et al., 2019) and via interactions with local climate (Classen et al., 2015). Woody encroachment can alter C and nutrient cycling, water availability, and pH, and can also drastically alter the spatial distribution of resources across a landscape (Eldridge et al., 2011; Myers‐Smith et al., 2011).…”

Woody encroachment in grassland elicits complex changes in the functional structure of above‐ and belowground biota

“…Indeed, mycorrhizal fungal communities differ between grasslands and forests (Tedersoo et al 2014, Davison et al 2015, Pärtel et al 2017). Notably, the encroachment of woody plants into grassland will simultaneously change soil conditions (Montané et al 2010, Grau et al 2019) and the availability of particular host plants (Schwob et al 2017), which in turn drives the changes in fungal communities. We therefore suggest that the strongest contrasts of community composition among the multi‐kingdom compositional shift in communities may be indicative of the most important ecological interactions or processes underlying community changes.…”

“…Woody plant encroachment influences grassland plant community composition (Kahmen and Poschlod 2008, Eldridge et al 2011, Ratajczak et al 2012, Jakobsson et al 2019). There is also evidence that woody plant encroachment causes changes in the composition of fungal (Yannarell et al 2014, Schwob et al 2017, Neuenkamp et al 2018, Grau et al 2019), nematode (Biederman and Boutton 2009), and collembolan (Kwok and Eldridge 2016) communities. Such widespread impacts were evidenced by simultaneous responses in multiple groups.…”

Encroachment of shrubs into subalpine grasslands in the Pyrenees changes the plant-soil stoichiometry spectrum

“…Shrub expansion is expected to cause several changes in ecosystem functioning, but few studies have focused on the impacts of expansion on the functioning of subalpine or alpine grasslands in the Pyrenees (Vitousek 1984;Montané et al 2007Montané et al , 2010; Barrio et al 2013;Catalan et al 2017;Grau et al 2019) and across Europe (MacDonald et al 2000;Wookey et al 2009). Some studies have reported that shrub encroachment has increased the carbon (C) and nitrogen (N) concentrations in the soil and reduced soil pH (Knapp et al 2008;Eldridge et al 2011), but such changes may strongly depend on shrub traits and ecosystem features.…”

“…Shrub and grass species have contrasting growth forms and differ in many functional traits of their adaptive and reproductive capacities and their strategies of resource acquisition and allocation (Chapin and Körner 1994). Different co-occurring shrub species may also have contrasting traits and strategies (Illa et al 2017), so the identity of shrubs is also crucial to our understanding of changes in ecosystem functioning when encroachment occurs (Grau et al 2019). Succession from grassland to shrubland is thus expected to cause important changes in the distribution, cycling and stoichiometry of chemical elements in the plant-soil system.…”