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Land use is increasingly recognized as a major driver of biodiversity and ecosystem functioning in many current research projects. In grasslands, land use is often classified by categorical descriptors such as pastures versus meadows or fertilized versus unfertilized sites. However, to account for the quantitative variation of multiple land-use types in heterogeneous landscapes, a quantitative, continuous index of land-use intensity (LUI) is desirable. Here we define such a compound, additive LUI index for managed grasslands including meadows and pastures. The LUI index summarizes the standardized intensity of three components of land use, namely fertilization, mowing, and livestock grazing at each site. We examined the performance of the LUI index to predict selected response variables on up to 150 grassland sites in the Biodiversity Exploratories in three regions in Germany(Alb, Hainich, Schorlheide). We tested the average Ellenberg nitrogen indicator values of the plant community, nitrogen and phosphorus concentration in the aboveground plant biomass, plant-available phosphorus concentration in the top soil, and soil C/N ratio, and the first principle component of these five response variables.
The LUI index significantly predicted the principal component of all five response variables, as well as some of the individual responses. Moreover, vascular plant diversity decreased significantly with LUI in two regions (Alb and Hainich).
Inter-annual changes in management practice were pronounced from 2006 to 2008, particularly due to variation in grazing intensity. This rendered the selection of the appropriate reference year(s) an important decision for analyses of land-use effects, whereas details in the standardization of the index were of minor importance. We also tested several alternative calculations of a LUI index, but all are strongly linearly correlated to the proposed index.
The proposed LUI index reduces the complexity of agricultural practices to a single dimension and may serve as a baseline to test how different groups of organisms and processes respond to land use. In combination with more detailed analyses, this index may help to unravel whether and how land-use intensities, associated disturbance levels or other local or regional influences drive ecological processes.
Very few principles have been unraveled that explain the relationship between soil properties and soil biota across large spatial scales and different land-use types. Here, we seek these general relationships using data from 52 differently managed grassland and forest soils in three study regions spanning a latitudinal gradient in Germany. We hypothesize that, after extraction of variation that is explained by location and land-use type, soil properties still explain significant proportions of variation in the abundance and diversity of soil biota. If the relationships between predictors and soil organisms were analyzed individually for each predictor group, soil properties explained the highest amount of variation in soil biota abundance and diversity, followed by land-use type and sampling location. After extraction of variation that originated from location or land-use, abiotic soil properties explained significant amounts of variation in fungal, meso-and macrofauna, but not in yeast or bacterial biomass or diversity. Nitrate or nitrogen concentration and fungal biomass were positively related, but nitrate concentration was negatively related to the abundances of Collembola and mites and to the myriapod species richness across a range of forest and grassland soils. The species richness of earthworms was positively correlated with clay content of soils independent of sample location and land-use type. Our study indicates that after accounting for heterogeneity resulting from large scale differences among sampling locations and land-use types, soil properties still explain significant proportions of variation in fungal and soil fauna abundance or diversity. However, soil biota was also related to processes that act at larger spatial scales and bacteria or soil yeasts only showed weak relationships to soil properties. We therefore argue that more general relationships between soil properties and soil biota can only be derived from future studies that consider larger spatial scales and different land-use types.
Estimating large herbivore density has been a major area of research in recent decades. Previous studies monitoring ungulate density, however, focused mostly on determining animal abundance, and did not interpret animal distribution in relation to habitat parameters. We surveyed large ungulates in the Biodiversity Exploratory Schorfheide-Chorin using faecal pellet group counts. This allowed us to explore the link between relative ungulate abundance, habitat use, and browsing damage on trees in a region with several types of forest, including unharvested and age-class beech forests, as well as age-class pine forests. Our results demonstrate that roe deer and fallow deer relative abundance is negatively correlated with large tree cover, and positively correlated with the cover of small shrubs (Rubus spec., Vaccinium spec.), and winter food supply. Habitat use of roe deer and fallow deer, as estimated by counting faecal pellet groups, revealed a preference for mature pine forests, and avoidance of deciduous forests. This differential habitat use is explained by different distributions of high quality food resources during winter. The response of deer to understory cover differed between roe deer and fallow deer at high cover percentages. The amount of browsing damage we observed on coniferous trees was not consistent with the relative deer abundance. Browsing damage was consistently higher on most deciduous trees, except for beech saplings which sustained less damage when roe deer density was low. Because roe deer is a highly selective feeder, it was reported to affect tree diversity by feeding only on trees with high nutritional value. Consequently, we propose that managing the number of all deer species by hunting is necessary to allow successful forest regeneration. Such an adjustment to deer numbers would need to account for both current tree diversity and alternative food resources. Our findings may be applicable to other forest landscapes in northeastern Germany including mature pine stands and differently harvested deciduous forests.
Functional biodiversity research explores drivers and functional consequences of biodiversity changes Land use change is a major driver of changes of biodiversity and of biogeochemical and biological ecosystem processes and services However, land use effects on genetic and species diversity are well documented only for a few taxa and trophic networks We hardly know how different components of biodiversity and their responses to land use change are interrelated and very little about the simultaneous, and interacting, effects of land use on multiple ecosystem processes and services Moreover, we do not know to what extent land use effects on ecosystem processes and services are mediated by biodiversity change Thus, overall goals are on the one hand to understand the effects of land use on biodiversity and on the other to understand the modifying role of biodiversity change for land-use effects on ecosystem processes, including biogeochemical cycles To comprehensively address these Important questions, we recently established a new large-scale and long-term project for functional biodiversity, the Biodiversity Exploratories (www biodiversity-exploratories de) They comprise a hierarchical set of standardized field plots in three different regions of Germany covering manifold management types and intensities in grasslands and forests They serve as a joint research platform for currently 40 projects involving over 300 people studying various aspects of the relationships between land use biodiversity and ecosystem processes through monitoring, comparative observation and experiments We introduce guiding questions, concept and design of the Biodiversity Exploratories - including main aspects of selection and implementation of field plots and project structure - and we discuss the significance of this approach for further functional biodiversity research This includes the crucial relevance of a common study design encompassing variation in both drivers and outcomes of biodiversity change and ecosystem processes, the interdisciplinary integration of biodiversity and ecosystem researchers, the training of a new generation of integrative biodiversity researchers, and the stimulation of functional biodiversity research in real landscape contexts, in Germany and elsewhere.