Seminatural areas act as reservoirs of genetic diversity for crop pollinators and natural enemies across Europe

Despite increasing recognition of the importance of the multiple dimensions of biodiversity, including functional or genetic diversity as well as species diversity, most conservation studies on ecosystem service-providing insects focus on simple diversity measures such as species richness and abundance. In contrast, relatively little is known about the genetic diversity and resilience of pollinators or natural enemies of crop pests to population fragmentation and local extinction. The genetic diversity and demographic dynamics of remnant populations of beneficial insects in agricultural areas can be a useful indicator proving additional insights into their conservation status, but this is rarely evaluated. Although gene flow between agricultural and seminatural areas is key to maintaining genetic diversity, its extent and directionality remain largely unexplored. Here, we apply a pan-European sampling protocol to quantify genetic diversity and structure and assess gene flow between agricultural and nearby seminatural landscapes in populations of two key ecosystem service-providing insect species, the lady beetle Coccinella septempunctata, an important predator of aphids and other crop pests, and the bee pollinator Andrena flavipes. We show that A. flavipes populations are genetically structured at the European level, whereas populations of C. septempunctata experience widespread gene flow across the continent and lack any defined genetic structure. In both species, we found that there is high genetic connectivity between populations established in croplands and nearby seminatural areas and, as a consequence, they harbor similar levels of genetic diversity. Interestingly, demographic models for some regions support asymmetric gene flow from seminatural areas to nearby agricultural landscapes. Collectively, our study demonstrates how seminatural areas can serve as genetic reservoirs of both pollinators and natural enemies for nearby agricultural landscapes, acting as sources for recurrent recolonization and, potentially, contributing to enhancing ecosystem service and crop production resilience in the longer term.image Our study demonstrates how seminatural areas can serve as genetic reservoirs of both pollinators and natural enemies for nearby agricultural landscapes, acting as sources for recurrent recolonization and, potentially, contributing to enhancing ecosystem service and crop production resilience in the longer term

Mobility, habitat selection and population connectivity of the butterfly Lycaena hellein in central Sweden

To be able to predict habitat quality and potential distribution of threatened species is key to developing successful conservation strategies for threatened species with fragmented distributions. The aim of this study was to assess factors that limit the local distribution and density ofLycaena helle, an endangered butterfly, in central Sweden, and to estimate its mobility in order to classify local populations according to their importance for the connectivity on a regional level. An additional aim was to test ifL. hellehabitat quality could be assessed using remotely-sensed data such as laser scanning (LiDAR). We derived potential predictors ofL. helleoccurrence from laser scanning data and used a resource selection function to assess their predictive power. We used a mark-recapture approach to studyL. hellemovement and estimate dispersal distances. The probability of occurrence ofL. helleincreased with higher solar irradiation and was negatively affected by sloping terrain, but the LiDAR data generally had low predictive power. Population density increased with host plant density, but this effect was weak. The mark-recapture study confirmed thatL. helleis very sedentary, with a mean movement distance of only 114 m and a maximum of 600 m. The studied population extends over a large network of interconnected linear habitats, which probably facilitates dispersal and thereby population persistence. Our study highlight the importance of a warm micro-climate and of man-made habitats like road verges and power-line corridors for the conservation ofL. helle

The usefulness of surrogates in biodiversity conservation: a synthesis.

Preserving biodiversity requires extensive information on species distributions and effectiveness of conservation actions. A surrogate approach, where a small number of species act as surrogates for broader groups of species, can simplify this task. Types of surrogates include indicator, umbrella, keystone and flagship species, and using diversity of higher taxonomic levels to represent species diversity. An overview of the empirical evidence of the usefulness of surrogates as a conservation tool is missing. We synthesised knowledge on if and when surrogate species are useful by systematically searching for meta-analyses and literature reviews assessing this. Results from 34 reviews revealed weak correlations between diversity of indicator species and other species and that umbrella species were not consistently useful for prioritising conservation actions. However, diversity of higher taxonomic levels can be representative of species diversity. No reviews have assessed the usefulness of keystone or flagship species. Thus, surrogate taxa often do not represent biodiversity or threatened species, and conservation actions aimed at surrogates might not necessarily benefit other species. However, surrogates are more likely to be useful when using a higher-taxon approach, when strong ecological similarities exists between a surrogate and other species, when surrogates are used at regional or landscape rather than local scales, and when using sets of multiple species as surrogates. As some use of surrogate species will always be necessary, surrogates should be carefully selected and their usefulness and cost-effectiveness should be assessed, including the risk that conservation actions aimed at that surrogate have unintended effects on other species

Microclimate in hollow trees and how it affects an inhabiting beetle species, Osmoderma eremita

Studies of species' responses to microclimatic conditions have increased our understanding of their habitat requirements and possible responses to climate warming. However, little is known about the role of microclimate for insects inhabiting hollow trees. We explored the relationship between tree characteristics and microclimate, and analysed how the microclimate in tree-hollows affects the occurrence and body size of an endangered beetle species, Osmoderma eremita. We placed temperature data-loggers in wood mould (= loose material in tree-hollows) and surveyed O. eremita in 47 hollows in oak pastures in south-eastern Sweden. We found that tree characteristics previously known to be associated with occurrence of beetle species confined to tree-hollows (larger diameters, more wood mould, entrances higher up, and not directed upwards) tend to decrease moisture and moisture variation, while their effects on temperature and temperature fluctuations differ during different seasons. This indicates that microclimatic conditions are important for beetles in hollow trees, and many specialised species seem to avoid conditions that are too moist. O. eremita occurred more frequently in trees with a warmer and more stable microclimate, while adult body size decreased with a warmer microclimate. A positive effect of a warmer microclimate was expected, since the study was done near the northern margin of the species' range. O. eremita is confined to living in hollow trees, which may be due to the microclimate there being more stable in comparison to both the ambient climate and the microclimate in standing and downed dead wood

Grasslands enhance ecosystem service multifunctionality above and below-ground in agricultural landscapes

Managing agricultural landscapes integrate production, biodiversity conservation and the flow of ecosystem services (ES) is of paramount importance to simultaneously meet production goals and environmental challenges. However, the response of farmland biodiversity and multiple ES to land-use change at multiple spatial scales remains poorly understood. We explored the effects of land-use at local (grassland vs. oilseed rape fields) and landscape scale (cover of permanent grasslands) on the provision of biodiversity (plants, arthropods, birds), five ES (pollination, pest control, soil fertility, carbon storage and water regulation) and overall ES-multifunctionality. ES-multifunctionality was higher in grasslands than in crop fields, by 25.2% above-ground and by 106.1% below-ground. Multiple threshold analyses highlighted a particularly poor level of performance for below-ground functions in crop fields. This habitat type was however capable of providing numerous above-ground functions simultaneously, although at low levels of performance when compared to the maximum values recorded in the study. Grasslands supported higher biodiversity and provision of pollination, soil fertility, carbon storage and water regulation. Landscape composition influenced the provision of multiple ES: a 10% increase in grassland cover in the landscape enhanced above-ground ES-multifunctionality by 11.0% in both habitats. In particular, grasslands cover in the landscape supported the provision of arthropod diversity, pollination and pest control provided by carabids. Synthesis and applications. The results of this field study show the key importance of preserving semi-natural grasslands in agricultural landscapes for the conservation of farmland biodiversity, for the protection of soils and the delivery of multiple ES critical for crop production. Maximization of multifunctionality necessitates the integration at the landscape scale (0.5-2 km) of semi-natural patches within the intensively farmed agricultural matrix. This would require not only the protection of existing grasslands, but also their restoration in simplified landscapes. The promotion of mixed farming (i.e., both crop and livestock production) might increase semi-natural grassland cover at the landscape scale

Microclimatic conditions mediate the effect of deadwood and forest characteristics on a threatened beetle species, Tragosoma depsarium

While climate change has increased the interest in the influence of microclimate on many organisms, species inhabiting deadwood have rarely been studied. Here, we explore how characteristics of forest stands and deadwood affect microclimate inside deadwood, and analyse how this affects wood-living organisms, exemplified by the red-listed beetle Tragosoma depsarium. Deadwood and forest variables explained much of the variation in temperature, but less of the variation in moisture within deadwood. Several variables known to influence habitat quality for deadwood-dependent species were found to correlate with microclimate. Standing deadwood and an open canopy generates warmer conditions in comparison to downed logs and a closed canopy, and shaded, downed and large-diameter wood have higher moisture and more stable daily temperatures than sun-exposed, standing, and small-diameter wood. T. depsarium occupancy and abundance increased with colder and more stable winter temperatures, and with higher spring temperatures. Consistently, the species occurred more frequently in deadwood items with characteristics associated with these conditions, i.e. downed large-diameter logs occurring in open conditions. Conclusively, microclimatic conditions were found to be important for a deadwood-dependent insect, and related to characteristics of both forest stands and deadwood items. Since microclimate is also affected by macroclimatic conditions, we expect species' habitat requirements to vary locally and regionally, and to change due to climate warming. Although many saproxylic species preferring sun-exposed conditions would benefit from a warmer climate per se, changes in species interactions and land use may still result in negative net effects of climate warming

Butterfly monitoring using systematically placed transects in contrasting climatic regions - exploring an established spatial design for sampling

Butterfly monitoring schemes are recording programs initiated to monitor nationwide butterfly abundance and distribution patterns, often with help from volunteers. The method generates high-resolution data, but may be associated with a degree of habitat sampling bias if volunteers prefer to survey areas perceived to be high-quality butterfly habitats. This can result in habitats becoming underrepresented in the data set, leading to less information about the butterfly populations there. In the present study, we investigate the possibility of applying a spatial design used by the Swedish Bird Survey for nationwide, grid-based sampling, with a goal to get butterfly monitoring data covering a representative sample of different habitats. We surveyed four 2x2 km sampling squares, split into 100 m segments, in the southernmost region of Sweden (Scania) and four in the northernmost region (Norrbotten). The grid-based transects were compared with volunteer-selected transects in a GIS analysis using a refined Swedish version of CORINE land cover data to see how well these two transect designs represent true habitat coverage. A total of 53 km transect was monitored, resulting in 490 individuals and 29 different species recorded. We found that transect cover correlated significantly with overall land cover using both monitoring methods, though standardised transects outperformed volunteer-selected transects in habitat representation in Scania, but not in Norrbotten. Butterflies were found to aggregate significantly in specific habitats, but with contrasting results for the two geographically different regions. Grasslands in both regions generated a high number of recorded butterflies, although so did clear-cut and residential areas in Norrbotten as well. The highest number of individuals recorded per transect was found in bogs in Scania. This study emphasises the value of complementing free site selection monitoring schemes with spatially representative schemes such as the Swedish Bird Survey, and sheds some light on general habitat preferences for Swedish butterflies in two contrasting climatic regions

Farmland biodiversity monitoring through citizen science: A review of existing approaches and future opportunities

Biodiversity monitoring in agricultural landscapes is important for assessing the effects of both land use change and activities that influence farmland biodiversity. Despite a considerable increase in citizen science approaches to biodiversity monitoring in recent decades, their potential in farmland-specific contexts has not been systematically examined. This paper therefore provides a comprehensive review of existing citizen science approaches involving biodiversity monitoring on farmland. Using three complementary methods, we identify a range of programmes at least partially covering farmland. From these, we develop a typology of eight programme types, reflecting distinctions in types of data collected and nature of volunteer involvement, and highlight their respective strengths and limitations. While all eight types can make substantial contributions to farmland biodiversity monitoring, there is considerable scope for their further development-particularly through increased engagement of farmers, for whom receiving feedback on the effects of their own practices could help facilitate adaptive management

Host plant density and patch isolation drive occupancy and abundance at a butterfly's northern range margin

Marginal populations are usually small, fragmented, and vulnerable to extinction, which makes them particularly interesting from a conservation point of view. They are also the starting point of range shifts that result from climate change, through a process involving colonization of newly suitable sites at the cool margin of species distributions. Hence, understanding the processes that drive demography and distribution at high-latitude populations is essential to forecast the response of species to global changes. We investigated the relative importance of solar irradiance (as a proxy for microclimate), habitat quality, and connectivity on occupancy, abundance, and population stability at the northern range margin of the Oberthur's grizzled skipper butterfly Pyrgus armoricanus. For this purpose, butterfly abundance was surveyed in a habitat network consisting of 50 habitat patches over 12 years. We found that occupancy and abundance (average and variability) were mostly influenced by the density of host plants and the spatial isolation of patches, while solar irradiance and grazing frequency had only an effect on patch occupancy. Knowing that the distribution of host plants extends further north, we hypothesize that the actual variable limiting the northern distribution of P. armoricanus might be its dispersal capacity that prevents it from reaching more northern habitat patches. The persistence of this metapopulation in the face of global changes will thus be fundamentally linked to the maintenance of an efficient network of habitats

Ekologisk kompensation som verktyg i miljömålsarbetet : Syntes från en forskningssatsning

Denna rapport utgör en syntes av de sju projekt som finansierades inom Naturvårdsverkets och Havs- och vattenmyndighetens forskningssatsning inom området ekologisk kompensation som pågick 2018–2021. Syntesprojektet har utgått dels från slutrapporterna från de enskilda projekten, dels från myndigheternas uttryckta önskemål om belysning av vissa specifika aspekter inom tillämpningen av ekologisk kompensation. Rapporten täcker därför inte in alla resultat och slutsatser från forskningsprojekten utan har inriktat sig på följande teman: (i) etiska argument kring ekologisk kompensation, (ii) förutsättningarna för lagstyrd och frivillig kompensation, (iii) modeller för beräkning av miljöskador och kompensationseffekter, och (iv) uppföljning och utvärdering av kompensationsåtgärder.Tillämpningen av ekologisk kompensation har idag en relativt begränsad omfattning, men skulle kunna utvecklas till ett mer använt styrmedel. I rapporten pekas dock på en rad aspekter som behöver åtgärdas och utvecklas för att ekologisk kompensation ska bidra till att förlusterna av biologisk mångfald och ekosystemtjänster stoppas eller vänds till en nettouppbyggnad av miljövärden. Syntesprojektet resulterade i en rad olika förslag riktade till berörda myndigheter som förväntas vara avgörande för ekologisk kompensation som styrmedel. Dessa summeras kortfattat nedan:Lagstiftning och nationell policy • Skadelindringshierarkin bör få ett starkt lagstöd och kopplingen mellan hierarkin och principen om tvådelad prövningen bör klargöras • Målet med ekologisk kompensation bör formuleras och uttryckas i lagstiftning och nationella policydokument • Lagstiftning bör tas fram gällande regler för när ekologisk kompensation inte ska tillämpas utan exploatering i stället helt ska undvikas • Utredning behövs kring om ett mål om nettovinst vid ekologisk kompensation bör formuleras i miljöbalken, respektive om det ska uttryckas tydligare som en del av de svenska miljökvalitetsmålen • Krav på systematisk uppföljning bör ingå som standard för alla kompensationsåtgärder baserade på beslut utifrån miljöbalken • Nationella riktlinjer bör utvecklas för uppföljning och utvärdering av ekologisk kompensation, och dessa bör även förtydliga vem som bär ansvaret för att utföra och bekosta dessaUtveckling av kompensationspooler • Ytterligare utredning bör göras kring förutsättningarna för att införa kompensationspooler i privat och offentlig regi, bland annat gällande ansvar samt sociala och samhällsekonomiska effekterFrivillig kompensation: kommunal och näringsliv • Nationellt gemensamma riktlinjer och utökad vägledning för frivillig kompensation bör utvecklas för att klargöra i. hur berörda aktörer kan och bör organisera arbetet med frivillig kompensation ii. hur målet med kompensationen bör definieras och i samband med det hur effekterna av införda kompensationsåtgärder bör följas upp • Tydligare stöd och riktlinjer bör utvecklas för vad som bör ingå i översiktsplaner, detaljplaner, grönplaner och naturvårdsplaner för att kunna skapa ett konsistent, transparent och mer strategiskt kommunalt arbete med kompensation, som också går att följa upp och utvärderaBeräkning och bedömning • Policydokument och riktlinjer bör upprättas för att styra handlingsutrymmet vad gäller naturtypisk, rumslig och tidsmässig flexibilitet inom ekologisk kompensation • Nationella riktlinjer bör av försiktighetsskäl förorda och rekommendera konkreta multiplikatorer för hantering av osäkerhet, även kopplat till samhällsekonomiska aspekter • Förslag bör tas fram på hur det går att förbättra möjligheterna att tillämpa ett landskapsperspektiv vid genomförande av ekologisk kompensation • Beräkningsmodeller som inkluderar samhällsekonomiska, sociala och ekologiska perspektiv bör utvecklas vidare, och dessa bör även beakta juridiska aspekter • Nationella riktlinjer bör utvecklas för vilka typer av mått på miljöegenskaper som företrädesvis kan tillämpas i beräkningen av omfattningen av ekologisk kompensation, samt i vilka fall som enklare specifika schablonvärden kan användasDelaktighet • Deltagandeprocesser bör utvecklas som främjar inkludering av berörda samhällsgrupper i beslutsfattande kring ekologisk kompensationKunskap, uppföljning och utvärdering • Riktlinjer bör utvecklas för hur data från initierade och genomförda kompensationsprojekt ska sammanställas och tillgängliggöras, samt en nationell databas tas fram för att stödja detta • En nationell geografisk databas bör tas fram för dokumentation av implementerade kompensationsområden för långsiktig uppföljnin