Grassland Butterflies Research Articles

Species-specific erosion of genetic diversity in grassland butterflies depends on landscape land cover

Changes in land cover, particularly agricultural intensification, are a primary cause of pollinator decline. Decline and isolation can reduce genetic diversity, reducing adaptive potential and unmasking genetic load. Maintenance of functional connectivity in changing landscapes is necessary to ensure persistence, but how land cover impacts genetic diversity and functional connectivity in butterflies remains poorly understood. We assess to which extent land cover functionally isolates grassland butterfly populations and what consequences isolation has for genetic diversity using whole genome and land cover data. We assess species-specific patterns across three butterfly species that vary in habitat specialization and mobility - Polyommatus icarus, Plebejus argus and Cyaniris semiargus - using samples from 6 to 11 populations across a ~25,000 km2 area in southern Sweden. We find that while generalist Po. icarus is nearly panmictic and heathland specialist Pl. argus maintains modest functional connectivity, grassland specialist C. semiargus exists in largely isolated populations. Genetic diversity in all species is positively related to grassland extent in the surrounding landscape. Arable and forest extent are positively and negatively related to genetic diversity in Po. icarus, while the inverse is true in C. semiargus. Lower functional connectivity in C. semiargus is coupled with higher rates of inbreeding, suggesting more urgent need of conservation action aimed at restoring functional connectivity in this species, illustrating how genetic data can reveal threats that may go unnoticed with abundance data alone. We conclude that specialist butterfly genetic diversity relies upon preservation of well-connected semi-natural grasslands to maintain functional connectivity at longer distances.

Oviposition preferences and larval survival of the marsh fritillary butterfly: The adverse impact of grazing

Abstract Species‐rich semi‐natural grasslands have been lost during the last century due to agricultural intensification. This has had large negative consequences for many specialised species, including grassland butterflies. To prevent further loss, management regimes in the remaining grasslands must maintain habitat quality over time, and we therefore need to understand the habitat preferences of specialised species and how different management regimes affect their survival. We studied the egg‐laying preferences of the threatened marsh fritillary butterfly in relation to host plant properties, microclimate and management (grazing) on Gotland, Sweden. Moreover, we followed the survival of eggs and larvae from 27 egg batches during a period of 8 months (from June 2020 to March 2021) in grazed and ungrazed areas. We found 92 egg batches in total and the average number of eggs was 184.5. Egg‐laying probability increased with increasing host plant size and abundance, and environmental variables associated with a warm microclimate (low grass cover, low vegetation height and south‐facing edges). The 27 egg batches that were followed over time had on average 203 eggs in June. Roughly 28% of the eggs developed into larvae, and about 17% of these survived over the entire study period, resulting in an overall 4.7% survival. Egg survival was higher in ungrazed habitats compared with grazed; in March (post‐hibernation), there were almost nine times more eggs in ungrazed habitats. This study highlights the complex habitat ecology of specialised butterflies and underscores the detrimental impact of intense grazing, advocating for rotational grazing or mowing regimes.

Indigenous forest edges increase habitat complexity and refuge opportunities for grassland butterflies

Heterogeneity at local and landscape scales can promote insect diversity and moderate insect declines that stem from global change. Determining how species respond to different landscape components provides insight into the role of heterogeneity in landscapes undergoing change. We examine how indigenous forest-grassland edges are used by butterflies. We assessed butterfly diversity and behaviour at forest edges and adjoining grassland, and tested whether these patterns are influenced by differing weather conditions between seasons. Forest edges supported a species rich butterfly assemblage. Forest specialists were more diverse at forest edges than in grassland, whereas grassland specialists and habitat generalists were as diverse at forest edges as in grassland. All butterfly groups showed more inter- and intra-specific interactions and more patrolling behaviour at forest edges, but more feeding and transient behaviour in grassland. Occurrence and behavioural patterns were not mediated by season, suggesting that the influence of forests does not change with varying environmental conditions. Nonetheless, certain species preferentially utilized forest edges in the hot and windy season, indicating that shelter provided by forest edges influences butterfly habitat use. We found no evidence that complementary nectar sources influence butterfly distribution patterns.Implications for insect conservation: The diverse butterfly assemblages and range of behaviours supported by indigenous forest edges indicate that forest patches are an important habitat component for butterflies. Conserving forest patches in these coastal grasslands may help buffer butterfly populations against global change.

Patch‐burn management affects grassland butterfly communities in cattle‐grazed rangelands

Abstract Grassland butterflies are undergoing worldwide population decline due to habitat loss and degradation. Rangelands in the Southern Great Plains can provide a habitat for grassland butterflies depending on management practices. Patch‐burn grazing is a management regime that involves burning portions of grazed pastures at different times. The combination of rotational fire and grazing creates a shifting mosaic of recently burned to older burned areas and lightly grazed to heavily grazed areas. However, the impact of fire and grazing on butterfly communities is complex and the effects of different management regimes on butterfly communities are not clear. We investigated the impact of time since prescribed fire and season of fire on butterfly communities in eight cattle‐grazed pastures, each with three burn units, in northern Oklahoma. Treatments included units burned in spring 2018, summer 2018, summer 2019, and spring 2020, with three replicates of each for a total of 12 burn units. Surveys were conducted three times per year in each burn unit in 2019 and 2020 using two standardised Pollard transects. A total of 909 butterflies and 35 species were observed. Species diversity varied by time since fire and season of fire, with spring‐burned sites having the lowest species diversity and summer‐burned sites having the highest. Dominant vegetation cover and blooming forb presence differed with time since fire and season of fire. Patch‐burn grazing creates a mosaic of successional vegetation stages which can benefit different butterfly species and support the overall community. Some species such as Cercyonis pegala, Danaus plexippus, and Atrytone arogos may benefit from fire every 1–2 years, while other species such as Echinargus isola may need longer times between fire treatments. Patch‐burn grazing regimes can support butterfly communities with species that need different fire return intervals by providing a mosaic of areas with different times since fire and associated grazing intensities.

Can cattle grazing benefit grassland butterflies?

Can cattle grazing benefit grassland butterflies?

Limestone quarries are the most important refuge for a formerly widespread grassland butterfly

Abstract Calcareous grasslands have an outstanding value for nature conservation. However, during the last century, they have suffered from severe area loss, fragmentation and degradation. Here, we studied the influence of macroclimate, landscape quality and habitat quality on populations of the Silver‐studded Blue, Plebejus argus, in calcareous grasslands and limestone quarries in a Central European landscape. Our study revealed that limestone quarries, especially those being actively managed, are the most important refuge for P. argus. Originally, the species was common in calcareous grasslands across the study area. More recently, however, patch occupancy was five times higher at quarries compared to calcareous grasslands and mean adult abundance nearly four times higher at occupied quarries than at occupied grasslands. The key driver of patch occupancy and adult abundance was a high abundance of the host plant. Adult abundance, additionally, increased with a sparse vegetation and a high cover of bedrock. The deterioration of habitat quality due to abandonment and decreasing grazing intensity has resulted in a strong decline of P. argus in calcareous grasslands. In contrast, quarries exhibit a very low successional speed due to their shallow soils. Hence, they are characterised by a high habitat quality for P. argus, i.e. dense stands of the host plant L. corniculatus, which grow on skeletal soils providing warm microclimatic conditions. Preserving limestone quarries with their early‐successional stages is of crucial importance for the conservation of P. argus.

Local and landscape responses of biodiversity in calcareous grasslands

Across Europe, calcareous grasslands become increasingly fragmented and their quality deteriorates through abandonment and land use intensification, both affecting biodiversity. Here, we investigated local and landscape effects on diversity patterns of several taxonomic groups in a landscape of highly fragmented calcareous grassland remnants. We surveyed 31 grassland fragments near Göttingen, Germany, in spring and summer 2017 for vascular plants, butterflies and birds, with sampling effort adapted to fragment area. Through regression modelling, we tested relationships between species richness and fragment size (from 314 to 51,395 m2), successional stage, habitat connectivity and the per cent cover of arable land in the landscape at several radii. We detected 283 plant species, 53 butterfly species and 70 bird species. Of these, 59 plant species, 19 butterfly species and 9 bird species were grassland specialists. Larger fragments supported twice the species richness of plants than small ones, and hosted more species of butterflies, but not of birds. Larger grassland fragments contained more grassland specialist plants, but not butterfly or bird specialists. Increasing amounts of arable land in the landscape from 20 to 90% was related to the loss of a third of species of plants, and less so, of butterflies, but not of birds. Per cent cover of arable land negatively correlated to richness of grassland specialist plants and butterflies, but positively to grassland specialist birds. We found no effect by successional stages and habitat connectivity. Our multi-taxa approach highlights the need for conservation management at the local scale, complemented by measures at the landscape scale.

Identifying fine‐scale habitat preferences of threatened butterflies using airborne laser scanning

AbstractAimLight Detection And Ranging (LiDAR) is a promising remote sensing technique for ecological applications because it can quantify vegetation structure at high resolution over broad spatial extents. Using country‐wide airborne laser scanning (ALS) data, we test to what extent fine‐scale LiDAR metrics capturing low vegetation, medium‐to‐high vegetation and landscape‐scale habitat structures can explain the habitat preferences of threatened butterflies at a national extent.LocationThe Netherlands.MethodsWe applied a machine‐learning (random forest) algorithm to build species distribution models (SDMs) for grassland and woodland butterflies in wet and dry habitats using various LiDAR metrics and butterfly presence–absence data collected by a national butterfly monitoring scheme. The LiDAR metrics captured vertical vegetation complexity (e.g., height and vegetation density of different strata) and horizontal heterogeneity (e.g., vegetation roughness, microtopography, vegetation openness and woodland edge extent). We assessed the relative variable importance and interpreted response curves of each LiDAR metric for explaining butterfly occurrences.ResultsAll SDMs showed a good to excellent fit, with woodland butterfly SDMs performing slightly better than those of grassland butterflies. Grassland butterfly occurrences were best explained by landscape‐scale habitat structures (e.g., open patches, microtopography) and vegetation height. Woodland butterfly occurrences were mainly determined by vegetation density of medium‐to‐high vegetation, open patches and woodland edge extent. The importance of metrics generally differed between wet and dry habitats for both grassland and woodland species.Main conclusionsVertical variability and horizontal heterogeneity of vegetation structure are key determinants of butterfly species distributions, even in low‐stature habitats such as grasslands, dunes and heathlands. The information content of low vegetation LiDAR metrics could further be improved with country‐wide leaf‐on ALS data or surveys from drones and terrestrial laser scanners at specific sites. LiDAR thus offers great potential for predictive habitat distribution modelling and other studies on ecological niches and invertebrate–habitat relationships.

Conservation of a strongly declining butterfly species depends on traditionally managed grasslands

Introduction:Due to land-use intensification at productive soils and abandonment of marginal farmland, biodiversity has dramatically declined throughout Europe. The dryad (Minois dryas) is a grassland butterfly that has strongly suffered from land-use change across Central Europe.Aims/Methods:Here, we analysed the habitat preferences of adult M. dryas and the oviposition-site preferences in common pastures located in mire ecosystems of the German pre-Alps.Results:Our study revealed that plot occupancy was equal at common pastures and control plots. However, the abundance of M. dryas was higher at common pastures, although the composition of vegetation types did not differ between the two plot types.Discussion:Open fens and transition mires traditionally managed as common pastures or litter meadows (= meadows mown in autumn to obtain bedding for livestock) were the main habitats of M. dryas in our study area. They offered (i) sufficient host plants (Carex spp.), (ii) had a high availability of nectar resources and (iii) a vegetation that was neither too sparse nor too short. In contrast, both abandonment and intensive land use had negative impacts on the occurrence of the endangered butterfly species.Implications for Insect ConservationBased on our study and other recent research from the common pastures, we recommend to maintain the current grazing regime to foster biodiversity in general and M. dryas in particular. Additionally, where possible, abandoned fens and transition mires adjacent to common pastures should be integrated into the low-intensity pasture systems. The preservation of traditionally managed litter meadows is the second important possibility to conserve M. dryas populations.

The decline of butterflies in Europe: Problems, significance, and possible solutions.

We review changes in the status of butterflies in Europe, focusing on long-running population data available for the United Kingdom, the Netherlands, and Belgium, based on standardized monitoring transects. In the United Kingdom, 8% of resident species have become extinct, and since 1976 overall numbers declined by around 50%. In the Netherlands, 20% of species have become extinct, and since 1990 overall numbers in the country declined by 50%. Distribution trends showed that butterfly distributions began decreasing long ago, and between 1890 and 1940, distributions declined by 80%. In Flanders (Belgium), 20 butterflies have become extinct (29%), and between 1992 and 2007 overall numbers declined by around 30%. A European Grassland Butterfly Indicator from 16 European countries shows there has been a 39% decline of grassland butterflies since 1990. The 2010 Red List of European butterflies listed 38 of the 482 European species (8%) as threatened and 44 species (10%) as near threatened (note that 47 species were not assessed). A country level analysis indicates that the average Red List rating is highest in central and mid-Western Europe and lowest in the far north of Europe and around the Mediterranean. The causes of the decline of butterflies are thought to be similar in most countries, mainly habitat loss and degradation and chemical pollution. Climate change is allowing many species to spread northward while bringing new threats to susceptible species. We describe examples of possible conservation solutions and a summary of policy changes needed to conserve butterflies and other insects.

Prescribed fire maintains host plants of a rare grassland butterfly

As grassland ecosystems transform globally due to anthropogenic pressures, improvements in our understanding of the effect of management on rare and threatened species in such landscapes has become urgent. Although prescribed fire is a very efficient tool for habitat restoration and endangered species management on fire-adapted ecosystems, the specific mechanisms underlying potential effects of burning on population dynamics of butterfly host plants are poorly understood. We analyzed a 12-year dataset (2004–2015), combining violet abundance, habitat physiognomy and fire history data from a fire-managed system, to determine factors influencing the spatiotemporal distribution and abundance of violets (Viola spp.), the host plants of the threatened eastern regal fritillary (Speyeria idalia idalia) butterfly. Our results demonstrate a critical role for fire in driving both presence and abundance of violets, suggesting management with prescribed fires can effectively promote butterfly host plants. In addition, we determined the character of habitats associated with violet presence and abundance, in particular a strong positive association with biocrusts. These results provide a roadmap for efficient site selection to increase the effectiveness of restoration efforts, including assessment of potential reintroduction sites for regal fritillary and other grassland butterflies and actions to promote the re-establishment of host plants in these sites.

Mark-release-recapture meets Species Distribution Models: Identifying micro-habitats of grassland butterflies in agricultural landscapes.

Habitat demands and species mobility strongly determine the occurrence of species. Sedentary species with specific habitat requirements are assumed to occur more patchy than mobile habitat generalist species, and thus suffer stronger under habitat fragmentation and habitat deterioration. In this study we measured dispersal and habitat preference of three selected butterfly species using mark-release-recapture technique. We used data on species abundance to calculate Species Distribution Models based on high-resolution aerial photographs taken using RGB / NIR cameras mounted on a UAV. We found that microhabitats for species with specific habitat requirements occur spatially restricted. In contrast, suitable habitats are more interconnected and widespread for mobile habitat generalists. Our models indicate that even managed grassland sites have comparatively little habitat quality, while road verges provide high quality micro-habitats. In addition, dispersal was more restricted for specialist butterfly species, and higher for the two other butterfly species with less ecological specialisation. This study shows synergies arising when combining ecological data with high precision aerial pictures and Species Distribution Models, to identify micro-habitats for butterflies. This approach might be suitable to identify and conserve high quality habitats, and to improve nature conservation at the ground.

Compositional Shifts in Forb and Butterfly Communities Associated with Kentucky Bluegrass Invasions

Rangeland management strategies impact biodiversity, the quality and quantity of ecosystem services, and overall rangeland resiliency. Previous management strategies, coupled with climate change, have led to widespread invasion by Kentucky bluegrass (Poa pratensis; bluegrass) in the Northern Great Plains, United States. Bluegrass invasions are expected to have detrimental impacts on biodiversity conservation and ecosystem services provided by rangelands. Yet none have investigated how bluegrass invasions influence pollinator populations, which are a prominent conservation concern and provide ecosystem services. We measured the impact of bluegrass invasion on mixed-grass prairie forb and butterfly communities. Obligate grassland butterflies, those that rely on grasslands, decreased as bluegrass cover increased, including the threatened Hesperia dacotae. Conversely, the abundance of facultative grassland butterflies, those found in grasslands but not fully dependent on them for their life history, increased as bluegrass increased. Moreover, plant species diversity and flowering forb species richness decreased as bluegrass cover increased. Overall, bluegrass invasion led to butterfly and plant community simplification, signaling a loss of biodiversity and potentially ecosystem services. Our research is the first to quantify how grassland butterflies and the floral resources they depend on are negatively impacted by bluegrass invasion. Resource managers should adopt management strategies that reduce bluegrass cover and improve nectar and host resources for obligate grassland butterflies. Management choices that removed disturbance regimes inherent to the Northern Great Plains (i.e., fire and grazing) led to bluegrass dominance in the region. Therefore, restoring disturbance regimes may be one way to reduce bluegrass and benefit pollinator populations.

How should we view temperate semi-natural grasslands? Insights from butterflies in Japan

In humid temperate regions, it has been commonly thought that closed forests represent original states and grasslands are unstable human artifacts that persist only as “semi-natural” states. This perspective underrates grasslands, because it makes the recent decline in grassland excusable. A contrasting perspective was recently proposed for temperate Europe and North America, stating that grasslands are intrinsically natural and stable, and hence could have survived without human presence during the postglacial age. However, few quantitative analyses have been performed to test the validity of these two perspectives. Considering that the evolutionary history of species is reflected in species traits, analyzing traits of grassland species in relation to habitat stability is expected to identify the intrinsic nature of grasslands (stable or unstable) and test the validity of these two perspectives. Here, using temperate Japanese butterflies, I compared ecological traits, geographic range, endemism and habitat types in the Eurasian continent between grassland species and forest (stable habitat) and ruderal (unstable habitat) species. I found that grassland butterflies shared similar ecological traits with forest butterflies, but not with ruderal butterflies. Moreover, grassland butterflies were primarily associated with natural and stable steppes and meadows in the Eurasian continent. Furthermore, Japanese grassland species are evolutionarily unique, nurturing many endemic subspecies with narrow geographic ranges. These results indicate that grasslands should not be regarded as unstable, transient, and artificial, but as intrinsically natural and stable in humid temperate regions. These grasslands may have persisted in a stable state without human intervention during the Holocene due to natural disturbances and severe environmental conditions, which are currently immensely suppressed or altered by human. Such perspective also holds true for humid temperate regions in Europe and North America. Thus, temperate semi-natural grasslands should be conserved with high priority in these regions considering that few natural grasslands are left resulting from the present intensive land use pressures and disturbance suppression.

Evaluating forest clear-cuts as alternative grassland habitats for plants and butterflies

Temperate semi-natural grasslands in Europe and East Asia have been rapidly declining and their conservation is urgently required. Although recent studies have indicated the importance of clear-cuts as alternative habitats for grassland butterflies, there is paucity of studies that directly compare biodiversity and habitat quality between grasslands and clear-cuts using multiple taxa. In this study, we compared the plant and butterfly richness between grasslands and clear-cuts, with a focus on the distribution of butterfly resources (nectaring flowers and host plants) and endangered plant and butterfly species, in a cool temperate area of central Japan. We established three or six transects in five grassland and five clear-cut sites, and measured the richness of plants and butterflies and environmental variables such as vegetation height and coverage at both transect and site levels. At the site level, there were no differences in the richness of all plants, butterflies, and butterfly host plants, but there were significant or marginal differences in the richness of endangered plants, butterflies, and butterfly host plants. Almost all endangered plants and butterflies were found in the overall grasslands, but only half of the endangered butterfly species were observed in the overall clear-cuts. At the transect level, species richness of endangered plants and butterflies peaked at an intermediate vegetation height. Our results indicate the primary importance of existing semi-natural grasslands and the necessity of management when the vegetation becomes too high. We recommend active creation of clear-cuts near or between the existing grasslands, so that clear-cuts can provide source or backup populations and act as stepping stones to connect the isolated grassland populations.

Multi-scale considerations for grassland butterfly conservation in agroecosystems

Global change threatens the persistence of multiple taxonomic groups, including butterflies. While conservation efforts for butterfly populations have increased, they are often hampered by a lack of true density estimates and a better understanding of ecological factors that influence density. Our objective was to enhance current grassland butterfly conservation efforts by using line-transect distance sampling to calculate density estimates and model the influence of landscape and local variables on butterfly density in the Northern Great Plains, USA. We calculated density for five obligate and ten facultative grassland species to produce one of the most extensive datasets for butterfly densities to date. In contrast to most previous research, we found that landscape variables influenced butterfly density more often than local variables. Specifically, the percent cover of perennial grasslands, crop lands, and wetlands appeared in 90% of species models, whereas common local variables—forb richness and invasive plant cover— appeared in 60% of best-ranked models. We expected the density of obligate butterfly species to decrease as invasive plants increased, but butterfly species' responses varied with larval diet, instead of habitat associations. Best-ranked models for Danaus plexippus and Speyeria idalia, two species of conservation concern with obligate host plants, did not include local host plant availability. Our results reiterate the importance of modeling species responses to variables across multiple scales and the potential benefits of conserving large tracts of grasslands. Although results emphasize the need for conservation at the landscape scale, managing for heterogeneous local scale variables will also help conserve grassland butterflies.

Threatened grassland butterflies as indicators of microclimatic niches along an elevational gradient – Implications for conservation in times of climate change

Among the factors that determine habitat quality for butterflies, an adequate microclimate is of crucial importance, especially for the less mobile immature stages. Due to their narrow microclimatic preferences, stenotopic butterflies are potential indicators of specific microclimatic niches. Although the outstanding importance of the microclimate is widely acknowledged, the thermal and hygric requirements of butterflies are usually inferred from habitat structure or regional climate instead of being exactly measured. Here, we present the results of year-round measurements of temperature and relative air humidity at typical oviposition microhabitats of three threatened grassland butterflies (Erebia medusa, Melitaea aurelia and Satyrium spini) inhabiting different zones along a climatic gradient in the Diemel Valley (Central Germany). Furthermore, we analysed how the climate in the study area has changed since the middle of the 20th century.The interspecific differences in mean temperature and humidity at the oviposition sites roughly reflected the differences in overall distribution of the three species, but separate analyses of day- and nighttime values revealed that local habitat characteristics and radiative heating of the near-ground air layer have a strong modifying effect on the microclimate.Since the 1950s, the climate in the Diemel valley has become significantly warmer. The magnitude of the observed increase in mean temperature was similar or even greater than the interspecific differences recorded by the microclimatic measurements. This implies that thermophilous species may expand their ranges within the Diemel Valley if climate warming continues. Species living in the relatively cool Upper Diemel Valley such as E. medusa, however, may incur population declines because there are few grasslands available at higher elevations or at microclimatically cooler sites such as north-facing slopes.

Urbanization promotes the loss of seasonal dynamics in the semi-natural grasslands of an East Asian megacity

The biodiversity of agricultural landscapes has been noticeably affected by rapid urbanization. Although many studies have examined species diversity per unit area (alpha diversity), knowledge about the patterns of species turnover (beta diversity) in urban areas remains limited. Furthermore, most beta diversity studies have focused on spatial heterogeneity; however, losses of temporal heterogeneity resulting from urbanization remain limited. In this study, we examined how urbanization is associated with decreases in the seasonal heterogeneity of species composition, which could be used as an indicator of the loss of seasonality by ecologists and policy makers aiming to conserve biodiversity. We investigated (1) changes in species richness based on seasonal averages (alpha diversity) and (2) the seasonal turnover of species composition (beta diversity) for flowering plants and butterflies along a rural-urban gradient in semi-natural grasslands. The response variables were alpha and beta diversity for flowering plants and butterflies, and the explanatory variables were urban areas within a 1-km radius of the center of each site. Increasing urban area caused both the seasonal alpha and beta diversity of flowering plants and butterflies to decline. These results supported the homogenization hypothesis for the seasonality of plants and butterflies in semi-natural grasslands of dominant urban areas in East Asia. Future studies should focus on investigating how urbanization is causing both declines in seasonality and changes in the spatial heterogeneity of species composition and associated biodiversity loss. Ecologists and policy makers should focus on developing strategies to halt the loss of temporal biological heterogeneity to maintain biodiversity.

Historical changes in grassland area determined the demography of semi-natural grassland butterflies in Japan

Semi-natural grassland areas expanded worldwide several thousand years ago following an increase in anthropogenic activities. However, semi-natural grassland habitat areas have been declining in recent decades due to changes in landuse, which have caused a loss of grassland biodiversity. Reconstructing historical and recent demographic changes in semi-natural grassland species will help clarify the factors affecting their population decline. Here we quantified past and recent demographic histories of Melitaea ambigua (Lepidoptera; Nymphalidae), an endangered grassland butterfly species in Japan. We examined changes in demography over the past 10,000 years based on 1378 bp of mitochondrial COI gene. We then examined changes in its genetic diversity and structure during the last 30 years using nine microsatellite DNA markers. The effective population size of M. ambigua increased about 3000-6000 years ago. In contrast, the genetic diversity and effective population sizes of many populations significantly declined from the 1980s to 2010s, which is consistent with a recent decline in the species population size. Our data suggest that the M. ambigua demography can be traced to changes in area covered by semi-natural grasslands throughout the Holocene.

Variation in grazing management practices supports diverse butterfly communities across grassland working landscapes

Landscape changes and resource exploitation have driven global biodiversity declines and reduced provision of ecological functions and services. In grassland working landscapes managed for ecological services and livestock production, it is essential to understand the influence of grazing practices on biodiversity to guide conservation. We used grassland butterflies to investigate the effects of four grazing management practices on biodiversity and pollination services from 2015 to 2016. We hypothesized grazing management practices would generate differing floristic resources that would thereby influence grassland butterfly community composition. To address our hypothesis, we sampled floral resources using belt transects and butterfly community and species level dynamics using line-transect distance sampling. We detected 2578 butterflies representing 34 species. Management practice was not a significant predictor of floral (p = 0.319) or butterfly community composition (p = 0.604), and sites under the same management showed dissimilarity in ordination space, indicating differences that may not be associated with grazing practices. At the species level, management explained density for six of nine butterfly species, but no individual management practice was optimal for a majority of detected species. Thus, over the timeframe of this study, grazing management practices did not generate differences in floristic community composition to drive community-level responses in grassland butterflies. Rather, management drove differences in individual species’ abundance within the butterfly community, likely contributing to the butterfly diversity observed at a broader scale.