Agri-environmental schemes: their role in reversing floral decline in the Brue floodplain, Somerset, UK

Trade-offs among ecosystem services advance the case for improved spatial targeting of agri-environmental measures

Agri-environmental measures (AEMs) are meant to foster environmentally-friendly farming techniques. The use of AEMs to enhance agroecosystem quality is still under debate due to site-specific spatial mismatches that often occur between adopted AEMs and delivered ecosystem services. Here, a site-specific approach was employed to assess the advantages and disadvantages of AEMs adopted from the Rural Development Programme and applied in the Veneto Region (NE Italy) during 2014-2020. Specifically, a DayCent model-GIS platform compared business-as-usual (BAU) and AEM scenarios. The effect of AEMs on ecosystem services was assessed by integrating high-resolution spatial data from multiple pedo-climates and land managements and combined agronomic and environmental outcomes. Results showed that AEM adoption generally improved ecosystem service delivery, especially by reducing water pollution and increasing soil fertility. Among simulated practices, permanent soil cover and minimum soil disturbance (i.e., conservation agriculture, pasture and meadow maintenance) produced the best results across the Veneto Region, despite compromises in agronomic performance due to AEM-specific commitments (e.g., narrow crop rotation in conservation agriculture, fertilizer use restrictions in pastures and meadows). Other AEMs (e.g., organic farming) appeared highly dependent on their spatial distribution and were influenced by a strong interaction between pedo-climatic characteristics (e.g., soil properties) and management techniques (e.g., type and quantity of nutrients input). The spatial-target approach is highly recommended to identify AEMs that achieve environmental quality objectives and develop indications as to where they should be encouraged to maximize ecosystem services delivery.

Farmers' Preferences for Future Agricultural Land Use Under the Consideration of Climate Change

Cultural landscapes in Austria are multifunctional through their simultaneous support of productive, habitat, regulatory, social, and economic functions. This study investigates, if changing climatic conditions in Austria will lead to landscape change. Based on the assumption that farmers are the crucial decision makers when it comes to the implementation of agricultural climate change policies, this study analyzes farmers' decision-making under the consideration of potential future climate change scenarios and risk, varying economic conditions, and different policy regimes through a discrete choice experiment. Results show that if a warming climate will offer new opportunities to increase income, either through expansion of cash crop cultivation or new land use options such as short-term rotation forestry, these opportunities will almost always be seized. Even if high environmental premiums were offered to maintain current cultural landscapes, only 43 % of farmers would prefer the existing grassland cultivation. Therefore, the continuity of characteristic Austrian landscape patterns seems unlikely. In conclusion, despite governmental regulations of and incentives for agriculture, climate change will have significant effects on traditional landscapes. Any opportunities for crop intensification will be embraced, which will ultimately impact ecosystem services, tourism opportunities, and biodiversity.

Effective long-distance pollen dispersal in Centaurea jacea

Background

Agri-environment schemes play an increasingly important role for the conservation of rare plants in intensively managed agricultural landscapes. However, little is known about their effects on gene flow via pollen dispersal between populations of these species.

Methodology/Principal Findings

In a 2-year experiment, we observed effective pollen dispersal from source populations of Centaurea jacea in restored meadows, the most widespread Swiss agri-environment scheme, to potted plants in adjacent intensively managed meadows without other individuals of this species. Potted plants were put in replicated source populations at 25, 50, 100 m and where possible 200 m distance from these source populations. Pollen transfer among isolated plants was prevented by temporary bagging, such that only one isolated plant was accessible for flower visitors at any one time. Because C. jacea is self-incompatible, seed set in single-plant isolates indicated insect mediated effective pollen dispersal from the source population. Seed set was higher in source populations (35.7±4.4) than in isolates (4.8±1.0). Seed set declined from 18.9% of that in source populations at a distance of 25 m to 7.4% at 200 m. At a distance of 200 m seed set was still significantly higher in selfed plants, indicating long-distance effective pollen dispersal up to 200 m. Analyses of covariance suggested that bees contributed more than flies to this long-distance pollen dispersal. We found evidence that pollen dispersal to single-plant isolates was positively affected by the diversity and flower abundance of neighboring plant species in the intensively managed meadow. Furthermore, the decline of the dispersal was less steep when the source population of C. jacea was large.

Conclusions

We conclude that insect pollinators can effectively transfer pollen from source populations of C. jacea over at least 200 m, even when “recipient populations” consisted of single-plant isolates, suggesting that gene flow by pollen over this distance is very likely. Source population size and flowering environment surrounding recipient plants appear to be important factors affecting pollen dispersal in C. jacea. It is conceivable that most insect-pollinated plants in a network of restored sites within intensively managed grassland can form metapopulations, if distances between sites are of similar magnitude as tested here.

Ecological restoration of farmland: progress and prospects

Sustainable agricultural practices in conjunction with ecological restoration methods can reduce the detrimental effects of agriculture. The Society for Ecological Restoration International has produced generic guidelines for conceiving, organizing, conducting and assessing ecological restoration projects. Additionally, there are now good conceptual frameworks, guidelines and practical methods for developing ecological restoration programmes that are based on sound ecological principles and supported by empirical evidence and modelling approaches. Restoration methods must also be technically achievable and socially acceptable and spread over a range of locations. It is important to reconcile differences between methods that favour conservation and those that favour economic returns, to ensure that conservation efforts are beneficial for both landowners and biodiversity. One option for this type of mutual benefit is the use of agri-environmental schemes to provide financial incentives to landholders in exchange for providing conservation services and other benefits. However, further work is required to define and measure the effectiveness of agri-environmental schemes. The broader potential for ecological restoration to improve the sustainability of agricultural production while conserving biodiversity in farmscapes and reducing external costs is high, but there is still much to learn, particularly for the most efficient use of agri-environmental schemes to change land use practice.