A plant diversity×water chemistry experiment in subalpine grassland

Biodiversity for multifunctional grasslands: equal productivity in high-diversity low-input and low-diversity high-input systems

“…Only a few experiments in grasslands have so far independently manipulated plant diversity and resource availability, and indeed much larger effects on grassland productivity were reported of resources than of diversity (He et al, 2002;Fridley, 2002Fridley, , 2003Dimitrakopoulos and Schmid, 2004;Spehn et al, 2005). In contrast, Rixen et al (2007) found comparable effects of nitrogen addition and increasing plant diversity, while Reich et al (2001) reported stronger effects of plant diversity than light fertilisation on productivity. Interestingly, however, the slope of the diversity-productivity relationship was steeper under high resource availability than under low resource availability in most of these cases.…”

Changes in Land Use of Pyrenean Mountain Pastures — Ski Runs and Livestock Management — Between 1972 and 2005 and the Effects on Subalpine Grasslands

“…Ski runs that have high proportions of bare ground are particularly prone to increases in surface runoff and further erosion during heavy rains (Wipf et al, 2005). Plant cover is probably the most important mechanism for preventing erosion in alpine habitats (Rixen et al, 2008b). An increase in bare ground cover, as recorded in our study, can lead to habitat fragmentation (Goñi and Guzmán, 2001), which is a serious threat to plant communities (Tilman et al, 1994) because of habitat loss, isolation, and habitat degradation (Ewers and Didham, 2006).…”

“…A thinner, denser snow cover has greater thermal conductivity than an intact snow cover, which leads to a reduction in soil insulation, an increase in frost penetration into the soil, and colder soil temperatures (Fahey and Wardle, 1998;Rixen et al, 2003;Wipf et al, 2005;Delgado et al, 2007;Rixen et al, 2008aRixen et al, , 2008bZeidler et al, 2008). As a result, snowmelt is retarded on ski runs, which shortens the growing season and affects plant species composition, as many studies have shown (Fahey and Wardle, 1998;Wipf et al, 2005;Rixen et al, 2008b;Zeidler et al, 2008). Grasses and some forbs are better adapted to a shorter growing period (Kudo, 1991) than are legumes, which might have led to the poor performance of legumes and the reduction in legume cover in the skiing area of our study between 1972 and 2005.…”

“…Those patches become desiccated and overheated, which leads to further erosion in the summer (Watson, 1985). Harsh highmountain conditions and the mechanical damage caused to plants by the construction and maintenance of ski runs greatly retards primary succession and the recovery of the vegetation cover (Rixen et al, 2003;Wipf et al, 2005;Roux-Fouillet et al, 2011); consequently, extensive areas can remain bare in these environments (Tsuyuzaki, 1994;Urbanska, 1997;Rixen et al, 2008b;Lorite et al, 2010).…”

“…The factors that cause changes in the vegetation are complex and diverse (Rixen et al, 2008b); for instance, snowpack compaction changes the biotic, physical, and chemical properties of the soil (Gros et al, 2004), such as lower soil temperatures (Rixen et al, 2003;Wipf et al, 2005;Delgado et al, 2007;Rixen et al, 2008a;Zeidler et al, 2008), changes in soil microbial life (Gros et al, 2004), a reduction in soil microporosity, and changes in nitrogen fixation (Delgado et al, 2007). The composition of plant communities can change because snowmelt is delayed on ski runs, which shortens the growing season (Wipf et al, 2005;Rixen et al, 2008a;Zeidler et al, 2008).…”