Orchard Meadows Research Articles

Patterns and drivers of scattered tree loss in agricultural landscapes: orchard meadows in Germany (1968-2009).

Scattered trees support high levels of farmland biodiversity and ecosystem services in agricultural landscapes, but they are threatened by agricultural intensification, urbanization, and land abandonment. This study aimed to map and quantify the decline of orchard meadows (scattered fruit trees of high nature conservation value) for a region in Southwestern Germany for the 1968 2009 period and to identify the driving forces of this decline. We derived orchard meadow loss from 1968 and 2009 aerial images and used a boosted regression trees modelling framework to assess the relative importance of 18 environmental, demographic, and socio-economic variables to test five alternative hypothesis explaining orchard meadow loss. We found that orchard meadow loss occurred in flatter areas, in areas where smaller plot sizes and fragmented orchard meadows prevailed, and in areas near settlements and infrastructure. The analysis did not confirm that orchard meadow loss was higher in areas where agricultural intensification was stronger and in areas of lower implementation levels of conservation policies. Our results demonstrated that the influential drivers of orchard meadow loss were those that reduce economic profitability and increase opportunity costs for orchards, providing incentives for converting orchard meadows to other, more profitable land uses. These insights could be taken up by local- and regional-level conservation policies to identify the sites of persistent orchard meadows in agricultural landscapes that would be prioritized in conservation efforts.

Understanding the Loss of Traditional Agricultural Systems: A Case Study of Orchard Meadows in Germany

In order to differentiate their products, agricultural producers are expanding and diversifying their use of marketing channels. Increasingly, these channels convey farm-level information to the final purchaser. However, the Census of Agriculture, the longest-running U.S. farm survey, tracks only three forms of market differentiation: direct-to-consumer sales, organic sales, and the number of community supported agriculture farms. Current Congressional proposals to increase data collection on market channel diversification rely on "follow-on" surveys and the Agricultural Resource Management Survey (ARMS) conducted by the U.S. Department of Agriculture. Both of these surveys are more limited than the Census of Agriculture in observing farm-level trends; the follow-on survey is particularly limited in providing results that are comparable to all farms and even farms within the same sector. This paper will show that administrative reporting changes in the 2012 census and the introduction of new questions for the 2017 census can improve both farm-level and sector-level observations on marketing channel usage — with greater precision than tracking local and regional food systems. Such data is needed to assist policy-makers, technical assistance providers, and farm lenders in providing resources to the relatively high portion of young, beginning, and full-time producers involved in market channel differentiation.

Analysing the maintenance and establishment of orchard meadows at farm and landscape levels applying a spatially explicit integrated modelling approach

Landscape elements can enhance the ecological and social value of agricultural landscapes. Orchard meadows are traditional landscape elements in Central Europe, but have deteriorated for decades due to their adverse economic effects. We apply an integrated modelling framework to assess the farm profitability of orchard meadows as well as the effectiveness of measures in the Austrian agri-environmental programme to maintain existing and establish new sites. The model results indicate that current market prices for fruits and harvest productivity levels are not sufficient to support the maintenance of existing sites. The model results also indicate that the agri-environmental measures are effective in maintaining orchard meadows, but are insufficient to make all existing sites profitable or support further establishments. Consequently, alternative policy options will aim at increasing harvest efficiencies (e.g. harvest mechanisation co-operatives), at adding value to orchard fruits (e.g. fruit processing options), and at reducing labour costs by improving seasonal labour availability.

Integration of bio-physical and economic models to analyze management intensity and landscape structure effects at farm and landscape level

We present an integrated spatially explicit land use modeling framework, which integrates two key components of agricultural systems, the bio-physical production system and the management system, by coupling the bio-economic farm optimization model FAMOS[space], the crop rotation model CropRota, and the bio-physical process model EPIC (Environmental Policy Integrated Climate). The integrated modeling framework has been developed to analyze the cost-effectiveness of selected agri-environmental program (AEP) measures. We also focus on the landscape development and therefore include a detailed representation of landscape elements such as fields or orchard meadows in our analysis. An indicator set represents all main environmental AEP objectives, i.e. preservation of water and soil resources, mitigation of climate change, protection of biodiversity, maintenance of cultural landscapes as well as farm income support. The integrated modeling framework is applied to 20 farms in the Austrian ‘Mostviertel’ region, which are selected from the Integrated Administration and Control System (IACS) of the European Union. The cost-effectiveness of AEP measures is assessed under different premium levels. The implementation of the AEP clearly affects environmental quality in a positive way. Nitrogen rates are reduced, landscape elements can be sustained, and the landscape becomes more diverse. The program also increases farm gross margins on average. However, the cost-effectiveness ratios (CER) are declining with increasing premium levels. The results indicate that the cost-effectiveness of AEP measures can be improved by spatial targeting.

DO RESOURCES OR NATURAL ENEMIES DRIVE BEE POPULATION DYNAMICS IN FRAGMENTED HABITATS

The relative importance of bottom-up or top-down forces has been mainly studied for herbivores but rarely for pollinators. Habitat fragmentation might change driving forces of population dynamics by reducing the area of resource-providing habitats, disrupting habitat connectivity, and affecting natural enemies more than their host species. We studied spatial and temporal population dynamics of the solitary bee Osmia rufa (Hymenoptera: Megachilidae) in 30 fragmented orchard meadows ranging in size from 0.08 to 5.8 ha in an agricultural landscape in central Germany. From 1998 to 2003, we monitored local bee population size, rate of parasitism, and rate of larval and pupal mortality in reed trap nests as an accessible and standardized nesting resource. Experimentally enhanced nest site availability resulted in a steady increase of mean local population size from 80 to 2740 brood cells between 1998 and 2002. Population size and species richness of natural enemies increased with habitat area, whereas rate of parasitism and mortality only varied among years. Inverse density-dependent parasitism in three study years with highest population size suggests rather destabilizing instead of regulating effects of top-down forces. Accordingly, an analysis of independent time series showed on average a negative impact of population size on population growth rates but provides no support for top-down regulation by natural enemies. We conclude that population dynamics of O. rufa are mainly driven by bottom-up forces, primarily nest site availability.

Importance of Habitat Area and Landscape Context for Species Richness of Bees and Wasps in Fragmented Orchard Meadows

Abstract: I investigated how habitat area, habitat connectivity, and landscape context affect the species richness and abundance of trap‐nesting bees, wasps, and their natural enemies. The research was done on 45 orchard meadows ranging in size from 0.08 to 5.8 ha and differing in habitat connectivity and the surrounding landscape matrix. Effects of the surrounding landscape matrix were restricted to circles with a radius of 250 m. Only the species richness of natural enemies increased with landscape diversity in the surrounding matrix. Population densities of bees increased with habitat connectivity. Total species richness and species richness of bees, eumenid wasps, and natural enemies significantly increased with habitat area. Significant species‐area relationships existed for insect groups but not for plants, thereby confirming the hypothesis that higher trophic levels are more affected by habitat fragmentation than lower trophic levels. The slope of species‐area relationships was steeper for mutualistic bees than for predatory wasps and natural enemies. In contrast to expectations, the rate of parasitism did not depend on habitat area but only on the local and regional abundance of hosts. My results suggest that the area and connectivity of habitat fragments is most important for the conservation of habitat specialists, whereas generalists may profit from a diverse surrounding landscape matrix.

Effects of habitat management on vegetation and above-ground nesting bees and wasps of orchard meadows in Central Europe

We studied the vegetation, stand structure and communities of above-ground nesting bees and wasps in 45 orchard meadows that were grazed, mown or abandoned (15 of each) in an agricultural landscape near Gottingen, Germany. Total species richness of plants was significantly lower and the proportion of dead wood was significantly higher on abandoned meadows compared to mown or grazed meadows. Species richness of bees, eumenid wasps and sphecid wasps did not differ between the three management types. Abundance of sphecid wasps was significantly higher on abandoned than on managed orchard meadows. Landscape context did not affect management type. The results suggest that management practises affect vegetation more significantly than the studied insect groups.

Succession of bee communities on fallows

Wild bee communities were studied on one‐ to five‐year‐old set‐aside fields with naturally developed vegetation (n=20), and old orchard meadows (n=4) to analyse effects of secondary succession on species diversity, resource use and associated life history traits. General theory predicts a steady increase of species richness with age of succession. In contrast, we found a first maximum in species richness of bees on two‐year‐old set‐aside fields and a second on old meadows. Successional changes of bee communities were related to changes of vegetation. The transition from pioneer successional stages, dominated by annuals, to early successional stages, dominated by perennials, resulted in the highest species richness of flowering plants in the second year within the first five years of succession. Species richness of flowering plants was the best predictor variable for species richness of bees, whereas the cover of flowering plants correlated with the abundance of bees. Annual plants were visited more often and perennials less often than expected from their flower cover. Halictidae tended to prefer flowers of annuals, whereas Megachilidae, Apidae and Anthophoridae significantly preferred perennials. In departure from successional theory, body size, proportion of specialised bees and proportion of parasitic bees did not significantly increase with successional age, but number of generations and the proportion of soil‐nesting bees decreased with successional age. Comparison of different management types showed that set‐aside fields with naturally developed vegetation supported much more specialised and endangered bee species than set‐aside fields sown with Phacelia tanacetifolia.