| 1. |
- Abdi, Abdulhakim M., et al.
(författare)
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Biodiversity decline with increasing crop productivity in agricultural fields revealed by satellite remote sensing
- 2021
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Ingår i: Ecological Indicators. - : Elsevier BV. - 1470-160X. ; 130
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Tidskriftsartikel (refereegranskat)abstract
- Increasing land-use intensity is a main driver of biodiversity loss in farmland, but measuring proxies for land-use intensity across entire landscapes is challenging. Here, we develop a novel method for the assessment of the impact of land-use intensity on biodiversity in agricultural landscapes using remote sensing parameters derived from the Sentinel-2 satellites. We link crop phenology and productivity parameters derived from time-series of a two-band enhanced vegetation index with biodiversity indicators (insect pollinators and insect-pollinated vascular plants) in agricultural fields in southern Sweden, with contrasting land management (i.e. conventional and organic farming). Our results show that arable land-use intensity in cereal systems dominated by spring-sown cereals can be approximated using Sentinel-2 productivity parameters. This was shown by the significant positive correlations between the amplitude and maximum value of the enhanced vegetation index on one side and farmer reported yields on the other. We also found that conventional cereal fields had 17% higher maximum and 13% higher amplitude of their enhanced vegetation index than organic fields. Sentinel-2 derived parameters were more strongly correlated with the abundance and species richness of bumblebees and the richness of vascular plants than the abundance and species richness of butterflies. The relationships we found between biodiversity and crop production proxies are consistent with predictions that increasing agricultural land-use intensity decreases field biodiversity. The newly developed method based on crop phenology and productivity parameters derived from Sentinel-2 data serves as a proof of concept for the assessment of the impact of land-use intensity on biodiversity over cereal fields across larger areas. It enables the estimation of arable productivity in cereal systems, which can then be used by ecologists and develop tools for land managers as a proxy for land-use intensity. Coupled with spatially explicit databases on agricultural land-use, this method will enable crop-specific cereal productivity estimation across large geographical regions.
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| 2. |
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| 3. |
- Ahrenfeldt, E J, et al.
(författare)
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Pollinator communities in strawberry crops - variation at multiple spatial scales.
- 2015
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Ingår i: Bulletin of Entomological Research. - 1475-2670. ; 105:4, s. 497-506
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Tidskriftsartikel (refereegranskat)abstract
- Predicting potential pollination services of wild bees in crops requires knowledge of their spatial distribution within fields. Field margins can serve as nesting and foraging habitats for wild bees and can be a source of pollinators. Regional differences in pollinator community composition may affect this spill-over of bees. We studied how regional and local differences affect the spatial distribution of wild bee species richness, activity-density and body size in crop fields. We sampled bees both from the field centre and at two different types of semi-natural field margins, grass strips and hedges, in 12 strawberry fields. The fields were distributed over four regions in Northern Europe, representing an almost 1100 km long north-south gradient. Even over this gradient, daytime temperatures during sampling did not differ significantly between regions and did therefore probably not impact bee activity. Bee species richness was higher in field margins compared with field centres independent of field size. However, there was no difference between centre and margin in body-size or activity-density. In contrast, bee activity-density increased towards the southern regions, whereas the mean body size increased towards the north. In conclusion, our study revealed a general pattern across European regions of bee diversity, but not activity-density, declining towards the field interior which suggests that the benefits of functional diversity of pollinators may be difficult to achieve through spill-over effects from margins to crop. We also identified dissimilar regional patterns in bee diversity and activity-density, which should be taken into account in conservation management.
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| 4. |
- Alexandridis, Nikolaos, et al.
(författare)
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Archetype models upscale understanding of natural pest control response to land-use change
- 2022
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Ingår i: Ecological Applications. - : Wiley. - 1051-0761 .- 1939-5582. ; 32:8
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Tidskriftsartikel (refereegranskat)abstract
- Control of crop pests by shifting host plant availability and natural enemy activity at landscape scales has great potential to enhance the sustainability of agriculture. However, mainstreaming natural pest control requires improved understanding of how its benefits can be realized across a variety of agroecological contexts. Empirical studies suggest significant but highly variable responses of natural pest control to land-use change. Current ecological models are either too specific to provide insight across agroecosystems, or too generic to guide management with actionable predictions. We suggest getting the full benefit of available empirical, theoretical and methodological knowledge, by combining trait-mediated understanding from correlative studies with the explicit representation of causal relationships achieved by mechanistic modeling. To link these frameworks, we adapt the concept of archetypes, or context-specific generalizations, from sustainability science. Similar responses of natural pest control to land-use gradients across cases that share key attributes, such as functional traits of focal organisms, indicate general processes that drive system behavior in a context-sensitive manner. Based on such observations of natural pest control, a systematic definition of archetypes can provide the basis for mechanistic models of intermediate generality that cover all major agroecosystems worldwide. Example applications demonstrate the potential for upscaling understanding and improving prediction of natural pest control, based on knowledge transfer and scientific synthesis. A broader application of this mechanistic archetype approach promises to enhance ecology's contribution to natural resource management across diverse regions and social-ecological contexts.
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| 5. |
- Alexandridis, Nikolaos, et al.
(författare)
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Models of natural pest control : Towards predictions across agricultural landscapes
- 2021
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Ingår i: Biological Control. - : Elsevier BV. - 1049-9644. ; 163
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Forskningsöversikt (refereegranskat)abstract
- Natural control of invertebrate crop pests has the potential to complement or replace conventional insecticide-based practices, but its mainstream application is hampered by predictive unreliability across agroecosystems. Inconsistent responses of natural pest control to changes in landscape characteristics have been attributed to ecological complexity and system-specific conditions. Here, we review agroecological models and their potential to provide predictions of natural pest control across agricultural landscapes. Existing models have used a multitude of techniques to represent specific crop-pest-enemy systems at various spatiotemporal scales, but less wealthy regions of the world are underrepresented. A realistic representation of natural pest control across systems appears to be hindered by a practical trade-off between generality and realism. Nonetheless, observations of context-sensitive, trait-mediated responses of natural pest control to land-use gradients indicate the potential of ecological models that explicitly represent the underlying mechanisms. We conclude that modelling natural pest control across agroecosystems should exploit existing mechanistic techniques towards a framework of contextually bound generalizations. Observed similarities in causal relationships can inform the functional grouping of diverse agroecosystems worldwide and the development of the respective models based on general, but context-sensitive, ecological mechanisms. The combined use of qualitative and quantitative techniques should allow the flexible integration of empirical evidence and ecological theory for robust predictions of natural pest control across a wide range of agroecological contexts and levels of knowledge availability. We highlight challenges and promising directions towards developing such a general modelling framework.
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| 6. |
- Allen-Perkins, Alfonso, et al.
(författare)
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CropPol : a dynamic, open and global database on crop pollination
- 2022
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Ingår i: Ecology. - : Wiley. - 0012-9658 .- 1939-9170. ; 103:3
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Tidskriftsartikel (refereegranskat)abstract
- Seventy five percent of the world's food crops benefit from insect pollination. Hence, there has been increased interest in how global change drivers impact this critical ecosystem service. Because standardized data on crop pollination are rarely available, we are limited in our capacity to understand the variation in pollination benefits to crop yield, as well as to anticipate changes in this service, develop predictions, and inform management actions. Here, we present CropPol, a dynamic, open and global database on crop pollination. It contains measurements recorded from 202 crop studies, covering 3,394 field observations, 2,552 yield measurements (i.e. berry weight, number of fruits and kg per hectare, among others), and 47,752 insect records from 48 commercial crops distributed around the globe. CropPol comprises 32 of the 87 leading global crops and commodities that are pollinator dependent. Malus domestica is the most represented crop (32 studies), followed by Brassica napus (22 studies), Vaccinium corymbosum (13 studies), and Citrullus lanatus (12 studies). The most abundant pollinator guilds recorded are honey bees (34.22% counts), bumblebees (19.19%), flies other than Syrphidae and Bombyliidae (13.18%), other wild bees (13.13%), beetles (10.97%), Syrphidae (4.87%), and Bombyliidae (0.05%). Locations comprise 34 countries distributed among Europe (76 studies), Northern America (60), Latin America and the Caribbean (29), Asia (20), Oceania (10), and Africa (7). Sampling spans three decades and is concentrated on 2001-05 (21 studies), 2006-10 (40), 2011-15 (88), and 2016-20 (50). This is the most comprehensive open global data set on measurements of crop flower visitors, crop pollinators and pollination to date, and we encourage researchers to add more datasets to this database in the future. This data set is released for non-commercial use only. Credits should be given to this paper (i.e., proper citation), and the products generated with this database should be shared under the same license terms (CC BY-NC-SA). This article is protected by copyright. All rights reserved.
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| 7. |
- Andersson, G., et al.
(författare)
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Arthropod populations in a sub-arctic environment facing climate change over a half-century: variability but no general trend
- 2022
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Ingår i: Insect Conservation and Diversity. - : Wiley. - 1752-458X .- 1752-4598. ; 15:5, s. 534-542
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Tidskriftsartikel (refereegranskat)abstract
- Dramatic declines of some arthropod populations have recently received a lot of attention. Identified declines have mainly been attributed to changes in agriculture, climate, pathogen prevalence and light pollution, as well as cross-regional effects of, e.g., drifting pesticides. However, the overall picture is complex and debated, and there is a need for systematically collected long-term data, not least from areas relatively unaffected by humans. We monitored the abundance of arthropods (mainly insects) in subalpine birch forest in Swedish Lapland over a period of 53 years (1968-2020), in an area comparatively unaffected by human activities. Arthropod abundance was assessed by yearly systematic counts on 24,000 birch shoots, in the second half of June. Animals were categorised into 17 different groups directly upon counting, dependent on taxonomy and life stage (imago, larva). Overall, there was no significant change in arthropod numbers. Nor did estimates of the total biomass of arthropods (using group-specific indices of the mass of individuals) show any significant trend. Accordingly, there are no signs that the arthropod abundance or biomass on birch in this subarctic study site has gone through the same declines as have been reported from sites in other habitats. The reason may be that the impact of factors identified worldwide as drivers of arthropod declines so far are small or non-existent because of the low human population density in this area.
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| 8. |
- Andersson, Georg, et al.
(författare)
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Effects of farming intensity, crop rotation and landscape heterogeneity on field bean pollination
- 2014
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Ingår i: Agriculture, Ecosystems & Environment. - : Elsevier BV. - 1873-2305 .- 0167-8809. ; 184, s. 145-148
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Tidskriftsartikel (refereegranskat)abstract
- Organic farming has the potential to enhance ecosystem services such as crop pollination. However, it is not known if a similar effect can be generated on conventional farms, without reducing external inputs such as inorganic fertilizers and pesticides, by using more complex crop rotations including ley for animal fodder production. In two separate designs, both located in southern Sweden, we tested if local organic farming and the landscape proportion of conventionally managed leys, along a landscape heterogeneity gradient, affected the pollination success of field bean. The number of developed pods was higher on organic farms compared to conventional ones. Development of beans, which demands high pollination efficiency, increased with increasing landscape heterogeneity, but only on organic farms. Increasing proportion of ley on conventional farms did not significantly influence the development of beans. The number of developed pods was not affected by the proportion of ley in the landscape. Our results demonstrate that in order to maximize pollination success it is important to improve both field management and preserve semi-natural habitats in the agricultural landscape. Reducing farming intensity with conventionally managed leys does not seem to be as effective as organic farming for delivering crop pollination services. (C) 2013 Elsevier B.V. All rights reserved.
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| 9. |
- Andersson, Georg K.S., et al.
(författare)
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Landscape-scale diversity of plants, bumblebees and butterflies in mixed farm-forest landscapes of Northern Europe : Clear-cuts do not compensate for the negative effects of plantation forest cover
- 2022
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Ingår i: Biological Conservation. - : Elsevier BV. - 0006-3207. ; 274
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Tidskriftsartikel (refereegranskat)abstract
- To assess the biodiversity consequences of contemporary land-use trends in Northern Europe, where agriculture is being replaced by forestry, we need a better knowledge of the contributions of constituting habitats to biodiversity. Here, we use purposefully collected data from 87 sites to model how agricultural habitats, including semi-natural pastures, sown temporary grassland (leys), cereal crops, and forest habitats comprising both mature production forests and clear-cuts, contribute to landscape-scale diversity of plants, bumblebees and butterflies in boreonemoral Sweden. At the local scale, species richness was highest in semi-natural pastures, intermediate in cereal crops and leys and lowest in forest. In clear-cuts, species richness was similarly high to that in semi-natural pastures. Countryside species-area models show that at a landscape scale, the high local richness in clear-cuts was more than offset by the low species richness encountered in forest. At landscape scale, semi-natural pastures, and in the case of plants also cereal crops, were major contributors of unique species. Leys and semi-natural pastures were both important contributors to bumblebee diversity. The effect of the surrounding landscape composition on local diversity was weak, suggesting that area-based approximations of landscape-scale species richness were reasonable. We conclude that clear-cuts constitute habitats for open-land species but cannot maintain landscape-scale diversity in the face of agricultural abandonment when open land is replaced by even-aged production forests. Maintaining farmland, in particular semi-natural pastures but also cereals and leys, is therefore critical to maintaining the landscape-scale species richness of plants and insects in forestry-dominated areas.
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