1,721,038 research outputs found
Artenvielfalt bewirtschafteter Grünlandsysteme ergebnisorientiert honorieren
No full textBiologische Vielfalt bildet die Grundlage für landwirtschaftliche Produktion, Ernährung und die Funktionsfähigkeit von Agrarökosystemen. Der zunehmende Verlust an Biodiversität stellt eine der größten Herausforderungen der Zukunft dar. Vor diesem Hintergrund ist es dringend notwendig, Agrarumweltprogramme als Instrument zur Erhaltung und Förderung der biologischen Vielfalt in Agrarökosystemen weiterzuentwickeln. Der folgende Beitrag zeigt am Beispiel von landwirtschaftlich genutztem Grünland, wie sich die pflanzliche Artenvielfalt durch eine ergebnisorientierte Honorierung erhalten lässt
Using selective herbicides to manage beneficial and rare weed species in winter wheat
No full textWeed species within arable farming systems act as a source of food and provide habitat for various taxa at higher trophic levels. Using field experiments in winter wheat, we investigated whether selective herbicides can be used as a potential tool for sustaining beneficial, less competitive weed species and rare species of high conservation value while controlling highly competitive weed species. We tested three selective herbicides with different active ingredients (amidosulfuron + iodosulfuron, fluroxypyr, mecoprop-P) at two application rates. We analysed cover of selected focal species (Centaurea cyanus and Papaver rhoeas) as well as weed species richness, winter wheat yield and weed community composition as influenced by herbicide treatments. Herbicide treatments involving fluroxypyr generally allowed for the selective retention of the regionally threatened weed species C. cyanus and P. rhoeas as a beneficial species of high value for associated trophic level and provided considerable control of the competitive species G. aparine. Herbicide treatments significantly affected weed species composition. The PRC method clearly showed the time-dependent herbicide treatment effects on weed community composition and allowed an estimate of the variance in species composition that is explained by the herbicide treatments. Our results indicated that applying selective herbicides can provide a feasible option for in-crop management of weed diversity by retention of beneficial or rare weed species occurring at moderate densities and control of highly-competitive weeds. However, weed control strategies must be tailored to site-specific conditions to account for increased abundance of competitive species
Artenvielfalt bewirtschafteter Grünlandsysteme ergebnisorientiert honorieren
No full textBiologische Vielfalt bildet die Grundlage für landwirtschaftliche Produktion, Ernährung und die Funktionsfähigkeit von Agrarökosystemen. Der zunehmende Verlust an Biodiversität stellt eine der größten Herausforderungen der Zukunft dar. Vor diesem Hintergrund ist es dringend notwendig, Agrarumweltprogramme als Instrument zur Erhaltung und Förderung der biologischen Vielfalt in Agrarökosystemen weiterzuentwickeln. Der folgende Beitrag zeigt am Beispiel von landwirtschaftlich genutztem Grünland, wie sich die pflanzliche Artenvielfalt durch eine ergebnisorientierte Honorierung erhalten lässt
Using selective herbicides to manage beneficial and rare weed species in winter wheat
No full textWeed species within arable farming systems act as a source of food and provide habitat for various taxa at higher trophic levels. Using field experiments in winter wheat, we investigated whether selective herbicides can be used as a potential tool for sustaining beneficial, less competitive weed species and rare species of high conservation value while controlling highly competitive weed species. We tested three selective herbicides with different active ingredients (amidosulfuron + iodosulfuron, fluroxypyr, mecoprop-P) at two application rates. We analysed cover of selected focal species (Centaurea cyanus and Papaver rhoeas) as well as weed species richness, winter wheat yield and weed community composition as influenced by herbicide treatments. Herbicide treatments involving fluroxypyr generally allowed for the selective retention of the regionally threatened weed species C. cyanus and P. rhoeas as a beneficial species of high value for associated trophic level and provided considerable control of the competitive species G. aparine. Herbicide treatments significantly affected weed species composition. The PRC method clearly showed the time-dependent herbicide treatment effects on weed community composition and allowed an estimate of the variance in species composition that is explained by the herbicide treatments. Our results indicated that applying selective herbicides can provide a feasible option for in-crop management of weed diversity by retention of beneficial or rare weed species occurring at moderate densities and control of highly-competitive weeds. However, weed control strategies must be tailored to site-specific conditions to account for increased abundance of competitive species
Plant species richness and composition in managed grasslands: The relative importance of field management and environmental factors
No full textDecline of grassland diversity throughout Europe within the last decades is threatening biological diversity and is a major conservation problem. There is an urgent need to determine the underlying factors that control vascular plant species richness and composition in managed grasslands. In this study, 117 grasslands were sampled using standardised methods. Explanatory variables were recorded for each grassland site, reflecting the local field management, site-specific environmental conditions and large-scale spatial trends. Using variation partitioning methods, we determined the pure and shared effects of these three sets of explanatory variables on the plant species richness and composition in grasslands. Most of the explained variation in plant species richness was related to the joint effect of local field management and environmental variables. However, the applied variation partitioning approach revealed that the pure effect of spatial variables contributed relatively little to explaining variation in both the plant species richness and species composition. The largest fractions of explained variation in plant species composition were accounted for by the pure effects of environmental and local field management variables. Moreover, the results revealed that the main mechanisms by which these sets of explanatory variables affect plant species vary according to the type of management regime under study. From our findings we could conclude that particularly a reduction of nitrogen fertilisation on meadows and grazing at a low stocking rate on pastures can help to conserve biodiversity
Additive partitioning of plant diversity with respect to grassland management regime, fertilisation and abiotic factors
No full textUnderstanding patterns of vascular plant diversity in managed temperate grasslands and the processes that determine them requires analyses at multiple spatial scales. In this study, we applied additive partitioning to plant species richness data of two contrasting management regimes (meadow vs. pasture) collected from a nested sampling design that consisted of two hierarchical scales. At the local scale, we quantified additive diversity components in 180 vegetation plots, and at the regional scale in 60 grassland parcels. Total observed regional species richness (γr) was partitioned into its additive components within (αl) and among vegetation plots (βl) and among grassland parcels (βr). We used the same approach in a comparison of common and infrequent plant species. Partitioning analyses revealed that the relative contributions of diversity components to total observed regional species richness changed as a function of spatial scale. We found that species richness among grassland parcels (βr) of both meadows and pastures contributed most to total observed regional species richness (γr) of all and infrequent plant species (up to 81% and 96%, respectively), whereas for common species only up to 51% of γr were attributable to species richness among grassland parcels (βr). To gain insight into the processes that may affect local patterns of species richness in grasslands, we analysed the observed local species diversity components with respect to management regime, nitrogen fertilisation and abiotic environmental factors (slope angle and soil quality). Our results show that grazing at a low-to-moderate stocking density promotes the β-diversity of all plant species at the local scale due to increased within-habitat heterogeneity. Low application rates of nitrogen fertilisers and abiotic environmental conditions such as steep slopes and soils with a low nutrient status generally benefited local species diversity components. We conclude that the observed patterns of plant species diversity are shaped by processes at multiple spatial scales.Um die Muster pflanzlicher Artenvielfalt im Wirtschaftsgrünland gemäßigter Klimate und die ihnen zugrundeliegenden Zusammenhänge verstehen zu können, sind Analysen auf multiplen räumlichen Skalen erforderlich. Um die Artenanzahl in zwei gegensätzlichen Managementsystemen (Wiese vs. Weide) zu analysieren, wurde in dieser Untersuchung der Ansatz der additiven Partitionierung verwendet. Die Daten wurden mit Hilfe eines räumlich genesteten Versuchsdesigns gewonnen, das aus zwei hierarchischen Skalen bestand. Auf der lokalen Skala wurden die additiven Diversitätskomponenten auf 180 Vegetationsparzellen bestimmt, während die Bestimmung der Komponenten auf regionaler Skala auf 60 Grünlandschlägen erfolgte. Die gesamte regionale Artenanzahl (γr) wurde in ihre additiven Komponenten innerhalb (αl) und zwischen den Vegetationsparzellen (βl) sowie zwischen den Grünlandschlägen (βr) aufgeteilt. Zusätzlich wurde die beschriebene Vorgehensweise für den Vergleich von häufig und selten vorkommenden Arten verwendet. Die Partitionsanalysen ergaben, dass sich der relative Beitrag der Diversitätskomponeten zur Gesamtartenzahl auf regionaler Ebene abhängig von der räumlichen Skala unterschied. Es zeigte sich, dass die Artenanzahl zwischen den Grünlandschlägen (βr) von sowohl Wiesen als auch Weiden den größten Beitrag zur Gesamtartenzahl (γr) auf regionaler Skala bei allen sowie bei selten vorkommenden Pflanzenarten leistete (bis zu 81% bzw. 96%). Dagegen konnte bei den häufig auftretenden Arten nur bis zu 51% von γr der Artenanzahl zwischen den Grünlandschlägen (βr) zugeordnet werden. Um Einblicke in die Prozesse zu erlangen, die den Artenreichtum auf Grünlandflächen beeinflussen, wurden die beobachteten Muster der lokalen Diversitätskomponenten auf ihre Abhängigkeit von Managementsystem, Stickstoffdüngung und abiotischen Umweltfaktoren (Hangneigung und Bodenqualität) untersucht. Die Ergebnisse weisen darauf hin, dass eine niedrige bis mittlere Besatzdichte die β-Diversität aller Pflanzenarten auf lokaler Skala durch eine Heterogenitätszunahme innerhalb des Habitates erhöhen kann. Geringe Stickstoffdüngungen und abiotische Umweltbedingungen wie steile Hanglagen und nährstoffarme Böden begünstigen generell die lokalen Diversitätskomponenten. Aus der durchgeführten Untersuchung lässt sich ableiten, dass die beobachteten Muster pflanzlicher Artenvielfalt durch Prozesse auf multiplen räumlichen Skalen gestaltet wurden
Effects of local factors on plant species richness and composition of Alpine meadows
No full textThe determinants of plant species richness and composition of meadows are often mutually related, showing joint effects on plant diversity. Thus, the specific objective of this paper was to evaluate the relative importance of soil, topography, and field management explanatory variables on plant species richness and composition of mown meadows in an area of the Southern Alps. The data consisted of 159 taxa sampled during the summer of 2003 in 56 10 × 10 m2 sampling plots. For each plot, 25 explanatory variables were recorded. The variation in species richness and composition was divided into the three sets of explanatory variables using a variation partitioning method. Species richness was mostly controlled both by the short-term effect of nitrogen fertilisation, and, as stressed by studies in other landscape contexts in Europe, by the long-term effect of soil phosphorus accumulation. The decrease of plant species number on the most fertile meadows was the consequence of the dominance of few competitors or ruderals, which prevented the establishment of small stress-tolerant species. In contrast to species richness, plant species composition presented an important pure effect of topography (altitude and slope). Species composition depended on several topography, soil, and field management factors. Thus, for both conservation and restoration of species-rich hay meadows, it is necessary to maintain a low level of soil P content, and to prevent the abandonment of parcels on steep slopes and in marginal areas, because these hosted the highest level of plant diversity
Plant species richness in grasslands - Relative importance of local site conditions and landscape structure
No full textPlant species richness in grasslands - Relative importance of local site conditions and landscape structure
No full textWater–energy, land‐cover and heterogeneity drivers of the distribution of plant species richness in a mountain region of the European Alps
No full textAim To evaluate the relative importance of water-energy, land-cover, environmental heterogeneity and spatial variables on the regional distribution of Red-Listed and common vascular plant species richness. Location Trento Province (c. 6200 km(2)) on the southern border of the European Alps (Italy), subdivided regularly into 228 3' x 5' quadrants. Methods Data from a floristic inventory were separated into two subsets, representing Red-Listed and common (i.e. all except Red-Listed) plant species richness. Both subsets were separately related to water-energy, land-cover and environmental heterogeneity variables. We simultaneously applied ordinary least squares regression with variation partitioning and hierarchical partitioning, attempting to identify the most important factors controlling species richness. We combined the analysis of environmental variables with a trend surface analysis and a spatial autocorrelation analysis. Results At the regional scale, plant species richness of both Red-Listed and common species was primarily related to energy availability and land cover, whereas environmental heterogeneity had a lesser effect. The greatest number of species of both subsets was found in quadrants with the largest energy availability and the greatest degree of urbanization. These findings suggest that the elevation range within our study region imposes an energy-driven control on the distribution of species richness, which resembles that of the broader latitude gradient. Overall, the two species subsets had similar trends concerning the relative importance of water-energy, land cover and environmental heterogeneity, showing a few differences regarding the selection of some predictors of secondary importance. The incorporation of spatial variables did not improve the explanatory power of the environmental models and the high original spatial autocorrelation in the response variables was reduced drastically by including the selected environmental variables. Main conclusions Water-energy and land cover showed significant pure effects in explaining plant species richness, indicating that climate and land cover should both be included as explanatory variables in modelling species richness in human-affected landscapes. However, the high degree of shared variation between the two groups made the relative effects difficult to separate. The relatively low range of variation in the environmental heterogeneity variables within our sampling domain might have caused the low importance of this complex factor
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