Will I stay or will I go? Plant species‐specific response and tolerance to high land‐use intensity in temperate grassland ecosystems

Abstract

Aim: Intensification of land use strongly impacts plant communities by causing shifts in taxonomic and functional composition. Mechanisms of land use-induced biodiversity losses have been described for temperate grasslands, but a quantitative assessment of species-specific occurrence optima and maximum tolerance (niche breadth) to land-use intensity (LUI) in Central European grasslands is still lacking.Location: Temperate, managed permanent grasslands in three regions of Germany. Methods:We combined extensive field work with a null model-randomization approach, defined a "habitat niche" for each plant species based on occurrence and abundance across 150 grassland sites differing in LUI (i.e., amount of fertilizer, mowing/grazing intensity and a compound index of these), and assessed their realized niche breadth (tolerance). Underlying mechanisms driving species' responses to LUI were assessed by relating plant functional traits, Ellenberg indicator values (EIV), Grime's ecological strategies (CSR) and Briemle utilization numbers.Results: Out of 151 plant species, 34% responded negatively, whereas 10% responded positively to high LUI. This pattern was mainly driven by species' response to fertilization and mowing frequency; grazing intensity response was less pronounced.Positively reacting species, displaying broader niches, were associated with competition-related functional traits, high EIV for nutrient supply and moisture and high mowing tolerance under spatiotemporally variable conditions. Negatively responding species, displaying relatively narrow niches confined to spatiotemporally homogeneous low LUI sites, were associated with a nutrient-retentive strategy, under nutrientpoor, base-rich soil conditions. Conclusion: Our analyses of individual species' reactions clearly demonstrate that species responding negatively to high LUI display little tolerance towards intensive fertilization and mowing, leading to plant diversity loss; whereas grazing partly thwarts these effects by creating new habitat niches and promoting ruderal species.Our approach can be applied to other habitat types and biogeographical regions in | 675 Additional supporting information may be found online in the Supporting Information section at the end of the article. Appendix S1. Main geographic and environmental characteristics of the Biodiversity Exploratory Regions Appendix S2. Ecological relevance of selected life history traits and ecological strategy types Appendix S3. Exploratory statistic values of all analysed variables and parameters over all species and sites Appendix S4. Correlation analysis of all analysed parameters with abundance-weighted mean niches and abundance-weighted niche breadth Appendix S5. Exploratory statistic values of species responding negatively, neutrally and positively to high intensity land-use Appendix S6. Complete list of plant species-specific abundanceweighted niche values and abundance-weighted niche breadths Appendix S7. Distribution of plant functional traits among "Winner", "Neutral" and "Loser" spec...

Nutrient‐demanding species face less negative competition and plant–soil feedback effects in a nutrient‐rich environment

“…EIVs are expressed as ordinal numbers, ranging from 1 to 9: species with higher indicator values for nutrients typically grow in more productive habitats, characterized by higher content of ammonium or nitrate ions and other macronutrients (phosphorus (P), potassium (K)) in the soil (Diekmann, ). It is common, however, to observe species differing in their EIVs‐N to co‐occur in the same plant communities (Chytrý & Rafajová, ; Busch et al ., ); that is, it is likely that the study species interact under field conditions.…”

“…Different levels of fertilization were achieved by adding a slow‐release fertilizer to half of the pots. In the study, we included central European grassland species differing in their nutrient requirements (as shown by Ellenberg indicator values for nutrients (EIVsN); Ellenberg et al ., ; Chytrý et al ., ), but observed to co‐occur (being thus likely to interact) within the same plant communities (as evidenced by records from vegetation plots; Chytrý & Rafajová, ; Busch et al ., ).…”

Narrow environmental niches predict land-use responses and vulnerability of land snail assemblages

“…In order to characterize the snail species’ responses to environmental conditions (land-use gradient, soil conditions), we calculated each species’ “environmental niche”. The method has been established in the context of the Biodiversity Exploratories and was applied to several taxa such as grasshoppers [ 30 ], cicadas, moths [ 31 ], bumblebees [ 54 ] or plants [ 55 ]. The “niche optimum” was calculated as the abundance weighted mean (AWM) for species i as where n p is the number of plots investigated, L p is the land-use gradient value of plot p , a i,p the abundance of species i in plot p and A i the total abundance of species i across all 149 forest or 134 grasslands sites, respectively.…”

Nitrogen availability and plant functional composition modify biodiversity-multifunctionality relationships

“…Slow growing species, with low SLA, are more competitive in the low nutrient environments they tend to dominate 28,29 and might therefore differ more in their competitive abilities for different nutrients, leading to nutrient use complementarity between slow growing species. In contrast, faster growing species, with high SLA, are abundant in high resource environments, where asymmetric light competition is prevalent 30,31 . Nutrient use complementarity between fast growing species might therefore be low.…”