Modification of the effective mesh size for measuring landscape fragmentation to solve the boundary problem

Patch-based landscape metrics can be biased by the boundaries and the extent of a reporting unit if the boundaries fragment patches. We call this the “boundary problem”. The effective mesh size m _eff is a convenient method to quantify landscape fragmentation, that is based on the probability that two points chosen randomly in a region will be connected, e.g., not be separated by roads, railroads, or urban development. The cutting-out (CUT) procedure, used in the original computation of m _eff, suffers from the boundary problem because the boundaries of the reporting units are considered to be additional barriers. Therefore, m _eff will be underestimated, particularly if reporting units are embedded within the broader landscape. In this paper, we present a solution to overcome this limitation by a new method called “cross-boundary connections” (CBC) procedure. It attributes the connections between two points that are located in different reporting units to both reporting units. We systematically compare the CBC procedure to the CUT procedure and show that the boundary problem is intrinsic to the CUT procedure, while the CBC procedure is independent of the size and administrative boundaries of reporting units. In addition, we elucidate the superior performance of the new procedure in the case study of South Tyrol where m _eff is being used for sustainability reporting on the level of municipalities. The new CBC procedure eliminates the bias due to the boundaries and the size of reporting units in measuring landscape fragmentation through m _eff.     

Landscape occupancy and local population size depends on host plant distribution in the butterfly Cupido minimus

We tested whether the landscape occupancy and local population size of the monophagous butterfly Cupido minimus can be predicted by patch size and isolation of its host plant or by other habitat characteristics. C. minimus and its larval food plant Anthyllis vulneraria are classified as rare and endangered in northern Germany. Adults of C. minimus are ranked as the most sedentary butterfly species in northern Europe.Around the city of Göttingen (Germany), we checked all known locations of A. vulneraria (n=70) in June 2002 for butterfly eggs (in blooming flowerheads) and adult butterflies (within 20-min transects).We found eggs of C. minimus or a high number of adults (>7) in all habitats with A. vulneraria (which are calcareous grasslands) even when isolated up to 2-4 km. In multiple regression analyses, local population size of adult butterflies was positively related to the cover of its larval food plant A. vulneraria explaining 65% of variance. Cover of A. vulneraria increased with increasing habitat area and increasing cover of plant species in flower and decreased with increasing cover of shrub layer. Habitat isolation and further factors describing habitat quality were not related to C. minimus population size or cover of its larval food plant.The results suggest that dispersal ability of C. minimus is greater than expected and that management should focus to increase A. vulneraria patches. For conservation, low impact grazing once a year and removing of excessive shrubs in winter seems to be the most appropriate strategies.     

Chloroacetanilides,oxyacetamides, tetrazolinones: mode of action. 1. Cross resistance and oleic acid incorporation in algal model systems

Results presented suggest that chloroacetamides, oxyacetamides, tetrazolinones, and possibly cafenstrole, act at the same site, although the precise molecular mode of action is still unknown, despite much research effort.     

Investigation of the volatile composition of pinotage wines fermented with different malolactic starter cultures using comprehensive two-dimensional gas chromatography coupled to time-of-flight mass spectrometry (GC×GC-TOF-MS)

Headspace solid phase microextraction in combination with comprehensive two-dimensional gas chromatography coupled to time-of-flight mass spectrometry (HS-SPME-GC × GC-TOF-MS) was used for the detailed investigation of the impact of malolactic fermentation (MLF) using three commercial Oenococcus oeni strains on the volatile composition of Vitis vinifera cv. Pinotage wines. GC × GC allowed the identification of 115 volatile compounds, including both major constituents and trace-level compounds, in a single analysis. A number of compounds differing in mean concentration levels between the control wines and those fermented with different starter cultures were shown for the first time to be influenced by MLF and/or the bacterial strain. Principal component analysis (PCA) provided excellent separation between the wines fermented with different MLF starter cultures and the control wine. Significantly different levels for some volatile compounds in wines fermented with one of the LAB starter cultures could be indicative of metabolic differences of this strain.     

Decreasing but still high: bycatch of seabirds in gillnet fisheries along the German Baltic coast

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Water and bromide transport in a heterogeneous glacial sand

We investigated water flow and bromide transport under agricultural field conditions, using TDR and tensiometer measurements as well as a bromide tracer experiment. The soil, an Albic Luvisol consisting of sand covering glacial loam, is highly heterogeneous with polygon nets formed by sand‐filled frost wedges. Water flow and bromide transport are influenced by the thickness of the glacial sand horizon and the soil structure. Both cause a variation of the actual evapotranspiration up to ± 25 mm/yr. Water and bromide are preferentially transported on the inclined soil layer boundaries into the sand wedges. From there infiltrating water may be redistributed into the surrounding glacial till. Approximately, the depths of the bromide centers of mass can be deduced using the piston flow concept. Small‐scale mass balances of the tracer show that vertical sections with bromide deficits and bromide surpluses are well balanced within a horizontal range of 1.8 m to 2.8 m. This distance is interpreted as the lateral influence of the sand wedges.     

Investigation of Spring Waters to Assess the Geo-ecological State of Landscape and Soil

The purpose of the investigation was to assess the opportunity to use spring waters as indicator for the load state of rural landscape ecosystems. In the periods from 2000-2003 and 2011-2012, the physical and chemical water quality of 55 freshwater springs in the German federal state of the Saarland was investigated in monthly intervals. The catchment areas of the springs represented the prevailing geological formations in the Saarland as well as the main land use types such as forest, grassland and arable land. The results show a clear correlation between the nitrate content and the share of arable land in the closer catchment area of the springs. The problem of acidification and related processes occurs mainly at the sites with acid parent rock material and accordingly substrates deficient in lime. Very low pH-values between 4 and 5 are observed and the aluminum concentration levels are consistently increased. Especially at sites with low calcium content in the geological substrate, a progressive destruction of the clay minerals can be assumed. In the extremely acidic spring waters, which showed the highest aluminum contamination during the measurement 10 years ago, the aluminum-values decreased slightly. This indicates that the clay minerals in these locations are already completely destroyed. Thus, it can be concluded that the investigation of spring waters provides information on the geo-ecological conditions in catchment areas. By means of the multi-temporal approach, changes of land use or other influences by human activities can be detected.