Sown wildflower strips for insect conservation: a review
TL;DR: Sown wildflower strips are increasingly being established in European countries within agri‐environmental schemes to enhance biodiversity, especially in intensively used agricultural areas.
Abstract: Sown wildflower strips are increasingly being established in European countries within agri-environmental schemes to enhance biodiversity, especially in intensively used agricultural areas. 2. The regulations vary between countries regarding the seed mixture, intensity of management and period of time over which subsidies are given. Insects in particular are intended to benefit from these schemes. 3. This review treats studies of insect diversity and abundance in sown wildflower strips. Schemes on wildflower strips in several countries in Central and Northern Europe are compared. 4. In a significant majority of studies, sown wildflower strips support higher insect abundances and diversity than cropped habitats. In general, numbers and diversity also tend to be higher than in other margin types such as sown grass margins and natural regeneration, but pollen- and nectar-rich flower mixtures may outperform them. 5. Common species are the main beneficiaries of the establishment of wildflower strips, although some studies point out the presence of rare or declining insect spe-
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TL;DR: It is suggested that the ecological contrast in floral resources created by schemes drives the response of pollinators to AES but that this response is moderated by landscape context and farmland type, with more positive responses in croplands and associated pollination services in species-poor landscapes.
Abstract: In Europe, agri-environmental schemes (AES) have been introduced in response to concerns about farmland biodiversity declines. Yet, as AES have delivered variable results, a better understanding of what determines their success or failure is urgently needed. Focusing on pollinating insects, we quantitatively reviewed how environmental factors affect the effectiveness of AES. Our results suggest that the ecological contrast in floral resources created by schemes drives the response of pollinators to AES but that this response is moderated by landscape context and farmland type, with more positive responses in croplands (vs. grasslands) located in simple (vs. cleared or complex) landscapes. These findings inform us how to promote pollinators and associated pollination services in species-poor landscapes. They do not, however, present viable strategies to mitigate loss of threatened or endangered species. This indicates that the objectives and design of AES should distinguish more clearly between biodiversity conservation and delivery of ecosystem services.
402 citations
Cites background from "Sown wildflower strips for insect c..."
...Although AES are, with the exception of some UK and Swiss schemes, not specifically targeted at pollinators (Rundl€of & Bommarco 2011), several measures within AES may potentially be beneficial (e.g. Kleijn et al. 2006; Haaland et al. 2011)....
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...Although AES are, with the exception of some UK and Swiss schemes, not specifically targeted at pollinators (Rundl€ of & Bommarco 2011), several measures within AES may potentially be beneficial (e.g. Kleijn et al. 2006; Haaland et al. 2011)....
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TL;DR: In this article, a range of policy initiatives have been promoted in recent years to address the decline of bee populations in Europe and North America, among these has been the establishment of flower-rich habitat within or around intensively farmed landscapes to increase the availability of pollen and nectar resources.
378 citations
Cites background from "Sown wildflower strips for insect c..."
..., 2006), and may depend on acceptance and popularity to farmers and the public (Haaland et al., 2011)....
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...…(Decourtye et al., 2010; Farley and Costanza, 010). nd Environment 159 (2012) 112– 122 113 The success of these schemes has been varied however (Kleijn and Sutherland, 2003; Kleijn et al., 2006), and may depend on acceptance and popularity to farmers and the public (Haaland et al., 2011)....
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...…the trend in the value of the ffect as well as the difficulty of achieving it. ontain redundant species (Carvell et al., 2006), omit some benficial species (Pywell et al., 2005) and like AES in general, may imply increase populations of already common pollinator species Haaland et al., 2011)....
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...The enhancement of pollinator habitat on farmland can take a number of forms, although the most often studied management techniques consist of field margin manipulation, including noncrop buffer strips which can provide nesting sites and encourage forage plant growth, the restoration of native plants in adjacent natural areas, wildflower strips sown with pollen- and nectar-rich plants, or a mixture of all three (Decourtye et al., 2010; Haaland et al., 2011)....
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...…including noncrop buffer strips which can provide nesting sites and encourage forage plant growth, the restoration of native plants in adjacent natural areas, wildflower strips sown with pollen- and nectar-rich plants, or a mixture of all three (Decourtye et al., 2010; Haaland et al., 2011)....
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TL;DR: This study provides a clear demonstration that wildlife-friendly management which supports ecosystem services is compatible with, and can even increase, crop yields.
Abstract: Ecological intensification has been promoted as a means to achieve environmentally sustainable increases in crop yields by enhancing ecosystem functions that regulate and support production. There is, however, little direct evidence of yield benefits from ecological intensification on commercial farms growing globally important foodstuffs (grains, oilseeds and pulses). We replicated two treatments removing 3 or 8% of land at the field edge from production to create wildlife habitat in 50–60 ha patches over a 900 ha commercial arable farm in central England, and compared these to a business as usual control (no land removed). In the control fields, crop yields were reduced by as much as 38% at the field edge. Habitat creation in these lower yielding areas led to increased yield in the cropped areas of the fields, and this positive effect became more pronounced over 6 years. As a consequence, yields at the field scale were maintained—and, indeed, enhanced for some crops—despite the loss of cropland for habitat creation. These results suggested that over a 5-year crop rotation, there would be no adverse impact on overall yield in terms of monetary value or nutritional energy. This study provides a clear demonstration that wildlife-friendly management which supports ecosystem services is compatible with, and can even increase, crop yields.
276 citations
TL;DR: The results of this study support the Agri-Environmental Schemes intended to promote honey bees and beekeeping sustainability through the enhancement of flower availability in agricultural landscapes.
Abstract: In intensive farmland habitats, pollination of wild flowers and crops may be threatened by the widespread decline of pollinators. The honey bee decline, in particular, appears to result from the combination of multiple stresses, including diseases, pathogens, and pesticides. The reduction of semi-natural habitats is also suspected to entail floral resource scarcity for bees. Yet, the seasonal dynamics and composition of the honey bee diet remains poorly documented to date. In this study, we studied the seasonal contribution of mass-flowering crops (rapeseed and sunflower) vs. other floral resources, as well as the influence of nutritional quality and landscape composition on pollen diet composition over five consecutive years. From April to October, the mass of pollen and nectar collected by honey bees followed a bimodal seasonal trend, marked by a two-month period of low food supply between the two oilseed crop mass-flowerings (ending in May for rapeseed and July for sunflower). Bees collected nectar mainly from crops while pollen came from a wide diversity of herbaceous and woody plant species in semi-natural habitats or from weeds in crops. Weed species constituted the bulk of the honey bee diet between the mass flowering crop periods (up to 40%) and are therefore suspected to play a critical role at this time period. The pollen diet composition was related to the nutritional value of the collected pollen and by the local landscape composition. Our study highlights (1) a food supply depletion period of both pollen and nectar resources during late spring, contemporaneously with the demographic peak of honey bee populations, (2) a high botanical richness of pollen diet, mostly proceeding from trees and weeds, and (3) a pollen diet composition influenced by the local landscape composition. Our results therefore support the Agri-Environmental Schemes intended to promote honey bees and beekeeping sustainability through the enhancement of flower availability in agricultural landscapes.
254 citations
TL;DR: In this article, the authors discuss the potential drivers of moth population decline and make suggestions for future research with a focus on quantifying impacts of land management practices, light pollution and climate change on moth population dynamics and developing evidence-based measures that can be incorporated into agri-environment schemes and other policy initiatives to help reverse the widespread decline of moths in Great Britain and beyond.
Abstract: Population declines among insects are inadequately quantified, yet of vital importance to national and global biodiversity assessments and have significant implications for ecosystem services. 2. Substantial declines in abundance and distribution have been reported recently within a species-rich insect taxon, macro-moths, in Great Britain and other Euro- pean countries. These declines are of concern because moths are important primary consumers and prey items for a wide range of other taxa, as well as contributing to ecosystem services such as pollination. 3. I summarise these declines and review potential drivers of change. Direct evi- dence for causes of moth declines is extremely limited, but correlative studies and extrapolation from closely related taxa suggest that habitat degradation (particularly because of agricultural intensification and changing silviculture) and climate change are likely to be major drivers. There is currently little evidence of negative popula- tion-level effects on moths caused by chemical or light pollution, non-native species or direct exploitation. 4. I make suggestions for future research with a focus on quantifying impacts of land management practices, light pollution and climate change on moth population dynamics and developing evidence-based measures that can be incorporated into agri-environment schemes and other policy initiatives to help reverse the widespread decline of moths in Great Britain and beyond.
246 citations
Cites background from "Sown wildflower strips for insect c..."
...Most studies, including those on moths, focus on recording changes in the abundance and species richness of adult animals in relation to management treatments and make no assessment of reproduction, immature stages or population dynamics (e.g. Feber et al., 1996; Pywell et al., 2004; Merckx et al., 2009b; Haaland et al., 2011)....
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...…on moths, focus on recording changes in the abundance and species richness of adult animals in relation to management treatments and make no assessment of reproduction, immature stages or population dynamics (e.g. Feber et al., 1996; Pywell et al., 2004; Merckx et al., 2009b; Haaland et al., 2011)....
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References
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TL;DR: In this article, the negative and positive effects of agricultural land use for the conservation of biodiversity, and its relation to ecosystem services, need a landscape perspective, which is difficult to be found in the literature.
Abstract: Understanding the negative and positive effects of agricultural land use for the conservation of biodiversity, and its relation to ecosystem services, needs a landscape perspective. Agriculture can contribute to the conservation of high-diversity systems, which may provide important ecosystem services such as pollination and biological control via complementarity and sampling effects. Land-use management is often focused on few species and local processes, but in dynamic, agricultural landscapes, only a diversity of insurance species may guarantee resilience (the capacity to reorganize after disturbance). Interacting species experience their surrounding landscape at different spatial scales, which influences trophic interactions. Structurally complex landscapes enhance local diversity in agroecosystems, which may compensate for local high-intensity management. Organisms with high-dispersal abilities appear to drive these biodiversity patterns and ecosystem services, because of their recolonization ability and larger resources experienced. Agri-environment schemes (incentives for farmers to benefit the environment) need to broaden their perspective and to take the different responses to schemes in simple (high impact) and complex (low impact) agricultural landscapes into account. In simple landscapes, local allocation of habitat is more important than in complex landscapes, which are in total at risk. However, little knowledge of the relative importance of local and landscape management for biodiversity and its relation to ecosystem services make reliable recommendations difficult.
3,460 citations
"Sown wildflower strips for insect c..." refers background in this paper
...…(Kotze & O’Hara, 2003), bugs (Frank&Künzle, 2006) and bees (Biesmeijer et al., 2006;Kohler et al., 2007), and the general homogenisation of the agricultural landscape is seen as one important factor driving these trends (Benton et al., 2003; Tscharntke et al., 2005; Diekotter et al., 2008)....
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..., 2007), and the general homogenisation of the agricultural landscape is seen as one important factor driving these trends (Benton et al., 2003; Tscharntke et al., 2005; Diekotter et al., 2008)....
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01 Jan 2005
TL;DR: In this article, the negative and positive effects of agricultural land use for the conservation of biodiversity, and its relation to ecosystem services, need a landscape perspective, which may compensate for local highintensity management.
Abstract: Understanding the negative and positive effects of agricultural land use for the conservation of biodiversity, and its relation to ecosystem services, needs a landscape perspective. Agriculture can contribute to the conservation of high-diversity systems, which may provide important ecosystem services such as pollination and biological control via complementarity and sampling effects. Land-use management is often focused on few species and local processes, but in dynamic, agricultural landscapes, only a diversity of insurance species may guarantee resilience (the capacity to reorganize after disturbance). Interacting species experience their surrounding landscape at different spatial scales, which influences trophic interactions. Structurally complex landscapes enhance local diversity in agroecosystems, which may compensate for local highintensity management. Organisms with high-dispersal abilities appear to drive these biodiversity patterns and ecosystem services, because of their recolonization ability and larger resources experienced. Agri-environment schemes (incentives for farmers to benefit the environment) need to broaden their perspective and to take the different responses to schemes in simple (high impact) and complex (low impact) agricultural landscapes into account. In simple landscapes, local allocation of habitat is more important than in complex landscapes, which are in total at risk. However, little knowledge of the relative importance of local and landscape management for biodiversity and its relation to ecosystem services make reliable recommendations difficult.
3,387 citations
TL;DR: In this paper, the authors argue that the loss of ecological heterogeneity at multiple spatial and temporal scales is a universal consequence of multivariate agricultural intensification and that future research should develop cross-cutting policy frameworks and management solutions that recreate that heterogeneity as the key to restoring and sustaining biodiversity in temperate agricultural systems.
Abstract: Agricultural intensification has led to a widespread decline in farmland biodiversity measured across many different taxa. The changes in agricultural practices affect many different aspects of the farmland habitat, but agricultural industry, policy and much previous research has tended to be concerned with specific sectors or practices (e.g. pesticide use or cereal husbandry). Here, we review the empirical literature to synthesize the research effort that has been directed to investigate specific practices or goals to make general statements regarding the causes and consequences of farmland biodiversity decline. We argue that the loss of ecological heterogeneity at multiple spatial and temporal scales is a universal consequence of multivariate agricultural intensification and, therefore, that future research should develop cross-cutting policy frameworks and management solutions that recreate that heterogeneity as the key to restoring and sustaining biodiversity in temperate agricultural systems.
2,773 citations
"Sown wildflower strips for insect c..." refers background in this paper
...…(Kotze & O’Hara, 2003), bugs (Frank&Künzle, 2006) and bees (Biesmeijer et al., 2006;Kohler et al., 2007), and the general homogenisation of the agricultural landscape is seen as one important factor driving these trends (Benton et al., 2003; Tscharntke et al., 2005; Diekotter et al., 2008)....
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..., 2007), and the general homogenisation of the agricultural landscape is seen as one important factor driving these trends (Benton et al., 2003; Tscharntke et al., 2005; Diekotter et al., 2008)....
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TL;DR: Evidence of declines (pre-versus post-1980) in local bee diversity in Britain and the Netherlands is found and a causal connection between local extinctions of functionally linked plant and pollinator species is strongly suggested.
Abstract: Despite widespread concern about declines in pollination services, little is known about the patterns of change in most pollinator assemblages. By studying bee and hoverfly assemblages in Britain and the Netherlands, we found evidence of declines (pre-versus post-1980) in local bee diversity in both countries; however, divergent trends were observed in hoverflies. Depending on the assemblage and location, pollinator declines were most frequent in habitat and flower specialists, in univoltine species, and/or in nonmigrants. In conjunction with this evidence, outcrossing plant species that are reliant on the declining pollinators have themselves declined relative to other plant species. Taken together, these findings strongly suggest a causal connection between local extinctions of functionally linked plant and pollinator species.
2,616 citations
"Sown wildflower strips for insect c..." refers background in this paper
...The picture is similar for other insect groups, for example beetles (Kotze & O’Hara, 2003), bugs (Frank&Künzle, 2006) and bees (Biesmeijer et al., 2006;Kohler et al., 2007), and the general homogenisation of the agricultural landscape is seen as one important factor driving these trends (Benton et…...
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TL;DR: In this article, the authors carried out a comprehensive search for studies that test the effectiveness of agri-environment schemes in published papers or reports and found that only 62 evaluation studies were found originating from just five EU countries and Switzerland (5).
Abstract: Summary 1. Increasing concern over the environmental impact of agriculture in Europe has led to the introduction of agri-environment schemes. These schemes compensate farmers financially for any loss of income associated with measures that aim to benefit the environment or biodiversity. There are currently agri-environment schemes in 26 out of 44 European countries. 2. Agri-environment schemes vary markedly between countries even within the European Union. The main objectives include reducing nutrient and pesticide emissions, protecting biodiversity, restoring landscapes and preventing rural depopulation. In virtually all countries the uptake of schemes is highest in areas of extensive agriculture where biodiversity is still relatively high and lowest in intensively farmed areas where biodiversity is low. 3. Approximately $ 24·3 billion has been spent on agri-environment schemes in the European Union (EU) since 1994, an unknown proportion of it on schemes with biodiversity conservation aims. We carried out a comprehensive search for studies that test the effectiveness of agri-environment schemes in published papers or reports. Only 62 evaluation studies were found originating from just five EU countries and Switzerland (5). Indeed 76% of the studies were from the Netherlands and the United Kingdom, where until now only c . 6% of the EU agri-environmental budget has been spent. Other studies were from Germany (6), Ireland (3) and Portugal (1). 4. In the majority of studies, the research design was inadequate to assess reliably the effectiveness of the schemes. Thirty-one percent did not contain a statistical analysis. Where an experimental approach was used, designs were usually weak and biased towards giving a favourable result. The commonest experimental design (37% of the studies) was a comparison of biodiversity in agri-environment schemes and control areas. However, there is a risk of bias if either farmers or scheme co-ordinators select the sites for agri-environment schemes. In such cases the sites are likely to have a higher biodiversity at the outset compared to the controls. This problem may be addressed by collecting baseline data (34% of studies), comparing trends (32%) or changes (26%) in biodiversity between areas with and without schemes or by pairing scheme and control sites that experience similar environmental conditions (16%). 5. Overall, 54% of the examined species (groups) demonstrated increases and 6% decreases in species richness or abundance compared with controls. Seventeen percent showed increases for some species and decreases for other species, while 23% showed no change at all in response to agri-environment schemes. The response varied between taxa. Of 19 studies examining the response of birds that included a statistical analysis, four showed significant increases in species richness or abundance, two showed decreases and nine showed both increases and decreases. Comparative figures for 20 arthropod studies yielded 11 studies that showed an increase in species richness or abundance, no study showed a decrease and three showed both increases and
1,399 citations
"Sown wildflower strips for insect c..." refers background in this paper
...The benefits of these schemes for biodiversity have recently been disputed, especially with regard to their very high costs (Kleijn & Sutherland, 2003; Berendse et al., 2004; Whitfield, 2006;Whittingham, 2007), but it has been argued that Correspondence: Christine Haaland, Department of Landscape…...
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