Norbert Sauberer

Landscape patch shape complexity as an effective measure for plant species richness in rural landscapes

The application of landscape patch shape complexity as a predictor ofvascularplant and bryophyte species richness is analysed. Several common complexityindices (shape index, fractal dimension, comparison to the area of the minimumbounding rectangle) are tested for their predictive power for plant speciesrichness. One new robust measure for shape complexity is presented whichovercomes some disadvantages of common complexity measures applied to highresolution analysis of agricultural landscapes based on aerial photographs. Thenew index is based on the number of shape characterising points along apolygon’s boundary. This new measure shows promising predictive capabilitiesforspecies richness of vascular plants and bryophytes (correlation coefficient:0.85 for vascular plants, 0.74 for bryophytes).

Surrogate taxa for biodiversity in agricultural landscapes of eastern Austria

In an agricultural landscape in eastern Austria eight terrestrial organism groups were investigated as potential biodiversity indicators. We present a cross-taxon congruence assessment obtained at the landscape scale using two groups of plants (bryophytes and vascular plants), five groups of invertebrates (gastropods, spiders, orthopterans, carabid beetles and ants) and one vertebrate taxon (birds). We tested four different approaches: correlated species counts, surrogate measures of the overall species richness that was assessed, a multi-taxa (or shopping basket) approach and a simple complementarity algorithm. With few exceptions, pairwise correlations between taxa, correlations between one taxon and the species richness of the remaining groups, and correlations between a combination of the richness of two taxa and the remaining species richness were highly positive. Complementarity-derived priority sets of sampling sites using one taxon as a surrogate for the pooled species richness of all other taxa captured significantly more species than selecting areas randomly. As an essential first step in selecting useful biodiversity indicators, we demonstrate that species richness of vascular plants and birds showed the highest correlations with the overall species richness. In a multi-taxa approach and in complementarity site selection, each of the eight investigated taxa had the capability to capture a high percentage of the overall species richness.

Landscape and vegetation responses to human impact in sandy coasts of Western Crete, Greece

Abstract Human activities have shaped the coastal environment of the Mediterranean basin for millennia through agriculture, husbandry and the deliberate use of fire. With the decline of agriculture, in recent decades, other factors have caused a more severe impact on the coastal landscapes. These factors are the large scale developments for tourism, the process of urbanisation, the increase of summer visitor numbers, and the introduction of exotic plants. The most heavily affected habitats are the sandy coastal systems, and coastal dunes in particular. The area of Western Crete presents a perfect example of these degradation processes. Our study area comprises both natural coastal dune systems, as well as degraded beaches with high intensity human impact. The north facing coasts of the study area consist of several long stretching sandy beaches with well developed dune systems. However, in many cases these dunes are severely degraded due to uncontrolled building of tourist facilities right at the edge of the shore. To the west, it includes sites of natural dunes of outstanding beauty, which are designated for inclusion in the Natura 2000 network. We use both landscape and vegetation classification, to establish the relations between human impact and vegetation. Two different classifications, derived from these different data-sets are combined, in order to extract useful information on the value of landscape surveying on biodiversity estimation, and on the other hand, on the perspectives of using plant species as indicators of landscape change. Diverse land unit groups are identified, according to human impact processes and structural landscape variation. These classes of land units correlate with specific plant communities that are recognised from the phytosociological analysis. Indicator species are defined that can explain the level of intensity of human impact for a stretch of beach. These indicator species often do not match the frequently used character species.

Setup, efforts and practical experiences of a monitoring program for genetically modified plants - an Austrian case study for oilseed rape and maize

Background, aim and scopeAccording to the Directive 2001/18/EC, genetically modified plants [GMPs] have to be monitored for unintended ecological impacts during their release. Detrimental effects on the biodiversity of agro-ecosystems represent a prime focus of such a monitoring. Although cropping of GMPs has already been permitted in the European Union, the establishment of appropriate monitoring networks lags behind. Here, we provide an overview on Biodiversity-Nature-Safety [BINATS], one of the first national monitoring programs specifically designed and implemented to accompany and survey GMP effects on the biodiversity of agricultural landscapes.Materials and methodsBINATS was implemented on 100 test areas (625 m × 625 m) which were selected based on a stratified random sampling design from all across the Austrian agricultural landscape with a focus on maize and oilseed rape cultivation. For each test area, the distribution of different habitat structures was mapped, and the species number of vascular plants, the species number and abundance of butterflies and grasshoppers, as well as the abundance of potential hybridisation partners of oilseed rape were recorded on ten randomly distributed sampling sites (circles, radius 20 m).Results and conclusionsImplementing BINATS resulted in a consistent database of the biodiversity and habitat configuration across parts of the Austrian agricultural landscapes. These data provide a baseline against which future biodiversity trends and their relationship with eventual GMP cropping can be evaluated. Moreover, they serve for assessing site-specific biodiversity-related risks of GMP cropping even in advance of their release. Finally, the first monitoring cycle (2007 and 2008) revealed insights into both the significance and the limits of such a monitoring program and allowed for a realistic calculation of the associated costs.Recommendations and perspectivesRegular reassessments of the BINATS network will provide valuable insights into the change of biodiversity in Austrian agricultural landscapes and their potential drivers. BINATS was specifically designed to collect such information at comparatively low costs. However, the BINATS approach is flexible enough to include additional indicators or monitoring objects to take account for future insights into their particular relevance in a GMP cropping context. The results obtained from the first BINATS cycle could not yet be correlated with GMP impacts since GMPs have not been commercially released in Austria so far. In this aspect, BINATS still needs to prove its suitability to relate biodiversity changes to GMP cropping. But it is intended to repeat the survey of the BINATS data in regular reassessments to improve our knowledge about the general biodiversity trends in agricultural landscapes free of GMP cropping. These baseline data should help to relate GMP-specific effects on biodiversity in future.

Habitat Structure, Quality and Landscape Predict Species Richness and Communities of Collembola in Dry Grasslands in Austria

We assessed the relationships between site size, habitat quality, landscape factors (fragmentation, landscape diversity) and species richness in communities of Collembola in 50 small dry grassland habitat patches in an agricultural landscape of eastern Austria. Grasslands in that region were once widespread and extensive, but have become increasingly fragmented and isolated. We hypothesized that dry grassland springtails species richness is significantly correlated with site variables (soil properties, habitat quality) and that the size of grassland sites is positively correlated with species richness. We used pitfall traps in 50 dry grasslands in differently structured agricultural landscapes and tested total abundance and three species richness measures: (1) the number of dry grassland specialist species; (2) total number of dry grassland species and (3) overall species richness. In the multivariate correlation models, we found that all species richness measures were significantly related to the plant species richness, a shape parameter of the sites, soil properties such as humus, temperature, sand and gravel content and the landscape variable reflecting isolation (distance to the nearest large dry grassland area). This landscape variable indicates that neighbouring grasslands are influencing the species richness of the sites. This may be a result of passive wind dispersal across the landscape or historic connection of the small sites with much larger dry grasslands. The size of the site did not show any significant correlation with total, dry grassland specialist, dry grassland generalist or generalist species richness. The small size of Collembola might explain these findings, because they have high population densities even in small patches.