Search

Vesistöjen ravinnekuormitus ja maatalousluonnon köyhtyminen ovat täpeltoviljelyn negatiivisia ympäristövaikutuksia. Monimuotoisuutta ja vesiensuojelua edistetään osaksi samoilla toimenpiteillä, esimerkiksi kesannoimalla. Ympäristö- ja maatalouspolitiikan kannalta on kiinnostavaa, kuinka suuria kustannussäästöjä on saavutettavissa, jos nämä toimenpiteet suunnitellaan alueellisesti koordinoidusti sekä monimuotoisuutta että vesiensuojelua silmälläpitäen. Tätä kysymystä voidaan tarkastella alueellisesti heterogeenisen pellonkäytönn optimointimallin avulla. Tutkimuksessa haettiin kustannustehokkaita toimenpideyhdistelmiä monimuotoisuuden ja vesiensuojelun yhteistuotannolle valuma-aluetasolla. Esimerkkialueena oli Lepsämänjoen valuma-alue Vantaanjoen vesistössä. Mallissamme viljelijä tekee päätöksiä peltojen maankäytöstä (ohranviljelyn ja erilaisten kesantojen välillä) sekä lannoituksen määrästä ohranviljelyaloilla. Malli sisältää kuvauksen erilaisten peltolohkojen ravinnekuormitusalttiudesta sekä asiantuntija-arvioihin perustuvan kuvauksen viljelypäätösten ja peltolohkojen ominaisuuksien vaikutuksesta peltoluonnon monimuotoisuuteen. Aineisto alueen maankäytöstä ja peltojen ominaisuuksista tallennettiin paikkatietojärjestelmään. Tämä tieto yhdistettiin toimenpiteiden vaikuttavuuden kanssa optimointimallissa. Tulostemme mukaan koordinoitu monimuotoisuuden ja vesiensuojelun suunnittelu tuottaa kustannussäästöjä verrattaessa tilanteeseen, jossa toimenpiteet suunnitellaan toisistaan riippumatta. Lannoituksen vähentäminen on tehokkain tapa aloittaa vesiensuojelu. Korkeampiin vesiensuojelullisiin tavoitteisiin pyrittäessä on kustannustehokasta yhdistää lannoituksen vähentämistä ohra-alalla viherkesantoalan kasvattamisee huuhtoutumisherkimmillä peltolohkoilla. Monimuotoisuuden edistämisessä tehokkain keino on niittykasviseoksella perustettu kesanto. Näitä kesantoja perustettiin tulosten mukaan ensin jyrkkärinteisimmille, metsään rajoittuville ja etelään avautuville peltolohkoille. Sekä vesiensuojelua että monimuotoisuutta edistävät taloudellisesti tehokkaat toimenpideyhdistelmät koostuivat sekä lannoituksen vähentämisestä että niittykasvialan lisäämisestä ja kohdentamisesta. Koordinoidulla monimuotoisuuden ja vesiensuojelun suunnittelulla saavutettavat kustannussäästöt ovat ehdollisia laskentamallin oletuksille, valuma-alueen ominaisuuksille, vaihtoehtoisten toimenpiteiden määrille ja niiden vaikuttavuudelle sekä myös sille missä suhteessa yhteiskunta arvostaa vesien- ja monimuotoisuuden suojelua.

Climate changes have profound effects on the distribution of numerous plant and animal species(1-3). However, whether and how different taxonomic groups are able to track climate changes at large spatial scales is still unclear. Here, we measure and compare the climatic debt accumulated by bird and butterfly communities at a European scale over two decades (1990-2008). We quantified the yearly change in community composition in response to climate change for 9,490 bird and 2,130 butterfly communities distributed across Europe(4). We show that changes in community composition are rapid but different between birds and butterflies and equivalent to a 37 and 114 km northward shift in bird and butterfly communities, respectively. We further found that, during the same period, the northward shift in temperature in Europe was even faster, so that the climatic debts of birds and butterflies correspond to a 212 and 135 km lag behind climate. Our results indicate both that birds and butterflies do not keep up with temperature increase and the accumulation of different climatic debts for these groups at national and continental scales.

The landscape matrix is suggested to influence the effect of habitat fragmentation on species richness, but the generality of this prediction has not been tested. Here, we used data from 10 independent studies on butterfly species richness, where the matrix surrounding grassland patches was dominated by either forest or arable land to test if matrix land use influenced the response of species richness to patch area and connectivity. To account for the possibility that some of the observed species use the matrix as their main or complementary habitat, we analysed the effects on total species richness and on the richness of grassland specialist and non-specialist (generalists and specialists on other habitat types) butterflies separately. Specialists and non-specialists were defined separately for each dataset. Total species richness and the richness of grassland specialist butterflies were positively related to patch area and forest cover in the matrix, and negatively to patch isolation. The strength of the species-area relationship was modified by matrix land use and had a slope that decreased with increasing forest cover in the matrix. Potential mechanisms for the weaker effect of grassland fragmentation in forest-dominated landscapes are (1) that the forest matrix is more heterogeneous and contains more resources, (2) that small grassland patches in a matrix dominated by arable land suffer more from negative edge effects or (3) that the arable matrix constitutes a stronger barrier to dispersal between populations. Regardless of the mechanisms, our results show that there are general effects of matrix land use across landscapes and regions, and that landscape management that increases matrix quality can be a complement to habitat restoration and re-creation in fragmented landscapes.

The importance of rotational fallows for pollinating insects in intensively cultivated farmland was studied in a three-year field experiment. The focus was on the establishment method (undersowing or seed mixture sown post-tillage), seed mixture (competitive Festuca pratensis – Phleum pratense – Trifolium pratense or less competitive Agrostis capillaris – Festuca ovina mixture) and duration (1 or 2 years) of the fallow. The seed mixture and duration affected the pollinators more than the method of establishment. Pollinator species richness was higher in fallows sown with less competitive than with competitive grasses and it increased in the second year. Stubble fields reached as high pollinator species richness already during the first year as fallows with less competitive grasses did in the second year. Pollinator abundance was highest in those treatments in which species richness of flowering plants was highest. The results suggest that the benefits of rotational fallows for pollinators increase when they are established as stubble or using seeds of less competitive grasses and when the field is fallowed for (at least) two summers.

Summary 1. Establishing temporal habitat patches, such as long-term set-aside, is potentially a valuable approach to support pollinator populations in intensively cultivated landscapes. The benefits of this approach are expected to differ between pollinator groups, because of fundamental differences in their ecology. 2. We studied the responses of two pollinator groups, bumblebees and diurnal Lepidoptera (butterflies and diurnal moths), to the vegetation succession in experimental set-aside during six consecutive years. The pollinators were monitored in 24 large treatment plots (50 · 50 m), sown with three different seed mixtures (competitive and two alternatives) and unmanaged or managed by mowing, and on 10 surrounding field margins. 3. The responses of the two pollinator groups to vegetation succession were distinctly different. Bumblebees showed a very strong positive response to the diverse seed mixture with abundant floral resources, and their abundance peaked in the first year. The species richness and abundance of Lepidoptera were increased gradually, suggesting differential colonization speeds of species and a gradual establishment of populations. Lepidopteran abundance reached the level of the field margins in 3 years, whereas the corresponding species richness level was not reached. The benefits of the alternative seed mixtures were less pronounced in Lepidoptera than in bumblebees. No effects of the mowing treatment on either species group were detected. 4. Within both pollinator groups, the response to vegetation succession was associated with species traits. In bumblebees, long-tongued species (indicating specialization) were increased during succession. In butterflies and diurnal moths, colonization success of species was strongly correlated with their wing span (indicating mobility). The most successful colonizers in butterflies were grass feeders and in diurnal moths the species feeding on leguminous plants at the larval stage. 5. Synthesis and applications. The ecological requirements of different pollinator groups should be taken into account when establishing set-aside. Supporting bumblebees is possible even on shortterm set-aside, assuming nectar and pollen sources are made available. The occurrence of butterflies and diurnal moths is strongly driven by additional factors, such as the availability of larval host plants as well as adult mobility, which calls for set-aside management regimes to be in place for several years.

Species are differentially affected by habitat fragmentation as a consequence of differences in mobility, area requirements, use of the matrix, and responses to edges. A quantitative understanding of these differences is essential not only for conservation biology but also for basic ecological theory. Here, we examine density responses by butterflies to patch size and use a quantitative theory on the scaling of population density with patch size to interpret results. Theory suggests that the density distribution of mobile species along a patch size gradient should depend on the scaling of net migration rates, whereas the density distribution of less mobile species should depend more on local growth. Using data from 11 localities in three European countries, we calculated the slope in the relationship between patch size and population density. These slopes were evaluated in relation to butterfly traits and matrix composition. As estimates of butterfly mobility we used both wing span and expert mobility rankings. The slope of the density–area relationship changed as predicted with wing span and the association of species to grasslands. Large and highly mobile species had a negative slope, similarly for grassland specialists and generalist species, and the slope matched quantitative predictions based on the scaling of net migration rates. Small and less mobile grassland specialists had a slope that was less negative than the slope of large and mobile grassland specialists, whereas the slope did not change with size for generalist species. These analyses suggest that the variability in response among butterfly species to patch size could be explained by accounting for body size/mobility and habitat associations among species. A caveat is that edge effects are not explicitly included in the model analysis, and future research should aim to combine area and edge effects in a common theoretical framework.

Intensification or abandonment of agricultural land use has led to a severe decline of semi-natural habitats across Europe. This can cause immediate loss of species but also time-delayed extinctions, known as the extinction debt. In a pan-European study of 147 fragmented grassland remnants, we found differences in the extinction debt of species from different trophic levels. Present-day species richness of long-lived vascular plant specialists was better explained by past than current landscape patterns, indicating an extinction debt. In contrast, short-lived butterfly specialists showed no evidence for an extinction debt at a time scale of c. 40 years. Our results indicate that management strategies maintaining the status quo of fragmented habitats are insufficient, as time-delayed extinctions and associated co-extinctions will lead to further biodiversity loss in the future.

Landscape simplification and habitat fragmentation may cause severe declines of less mobile and habitat specialist species and lead to biotic homogenization of species communities, but large-scale empirical evidence on biotic homogenization remains sparse. We sampled butterfly and day-active geometrid moth communities within 134 differently fragmented landscapes in Finland situated in five geographical regions. Overall species richness was partitioned into alpha and beta diversity and butterflies were assigned a species-specific mobility rank and habitat specificity score based on published ecological trait classifications. Alpha and beta diversity of butterflies and geometrid moths decreased with increasing agricultural intensity, independently of geographical position. The responses were either linear or nonlinear with accelerating decrease of diversity when arable field cover exceeded 60%. Mobility rank and percentage generalists of butterfly communities increased linearly with increasing field cover. In landscapes with high agricultural intensity (>60% field coverage), the decrease in beta diversity of butterflies was strongly associated with an increasing proportion of habitat generalists and increasing average mobility in the butterfly communities. However, there was no such relationship in landscapes with low or moderate agricultural intensity. Synthesis and applications. We demonstrate that biotic homogenization caused by land-use change arises as a consequence of the loss of habitat specialists and poor dispersers in intensively cultivated landscapes with simplified landscape structure. Agri-environment schemes will therefore be inefficient in protecting high beta diversity unless they explicitly increase habitat availability and connectivity for habitat specialists and poor dispersers. © 2010 The Authors. Journal compilation © 2010 British Ecological Society. (Less)

This study provides a novel systematic comparative analysis of the species characteristics affecting the range margin shifts in butterflies towards higher latitudes, while taking phylogenetic relatedness among species into account. We related observed changes in the northern range margins of 48 butterfly species in Finland between two time periods (1992–1996 and 2000–2004) to 11 species traits. Species with positive records in at least ten 10 km × 10 km grid squares (in the Finnish National Butterfly Recording Scheme, NAFI) in both periods were included in the study. When corrected for range size change, the 48 butterfly species had shifted their range margins northwards on average by 59.9 km between the study periods, with maximum shifts of over 300 km for three species. This rate of range shifts exceeds all previously reported records worldwide. Our findings may be explained by two factors: the study region is situated in higher latitudes than in most previous studies and it focuses on the period of most prominent warming during the last 10–15 years. Several species traits exhibited a significant univariate relationship with the range margin shift according to generalized estimation equations (GEE) taking into account the phylogenetic relatedness among species. Nonthreatened butterflies had on average expanded their ranges strongly northwards (84.5 km), whereas the distributions of threatened species were stationary (−2.1 km). Hierarchical partitioning (HP) analysis indicated that mobile butterflies living in forest edges and using woody plants as their larval hosts exhibited largest range shifts towards the north. Thus, habitat availability and dispersal capacity of butterfly species are likely to determine whether they will be successful in shifting their ranges in response to the warming climate.

This study examined how species richness of butterflies with differing population trends is affected by land cover and climate. Generalized linear models (GLM) with land cover, climate and geographical location as explanatory variables were constructed to explain variation in species richness of declining, stable and increasing butterflies in 10-km squares in Finland. The largest part of explained variation in species richness of all the three butterfly trend categories was related to spatially structured climate variables and pure geographical location. However, the relative importance of climate and land cover differed between the butterfly categories. Pure and spatially structured climate variables explained two-fold more variation in species richness in increasing butterflies than in stable and declining butterflies. On the other hand, pure and spatially structured land cover variables explained 2.5–6 times more variation in species richness in declining butterflies than in stable and increasing butterflies. Land cover variables differed in their effects on the species richness of the three trend categories: the amount of grassland had the greatest positive effect on the number of declining species, whereas the amount of forest was the most important land cover variable for species richness of stable butterflies and arable land and field-forest mosaic for species richness of increasing butterflies. The results suggest that habitat availability has the greatest effect on the trends of declining butterfly species, and climate in concert with habitat availability on the trends of increasing species.

The determinants of local species richness of diurnal Lepidoptera were studied in 68 agricultural landscapes in five geographic regions by sampling field margins, road verges, forest edges and patches of semi-natural grassland. Butterflies and day-active moths were counted and habitat quality was measured in 1191 separate 50 m transects. Generalized linear mixed models (GLMM) were built to explain patterns of species richness by first adjusting for the effects of geographic location and weather conditions during the butterfly counts. Habitat type and quality largely determined local species richness, whereas the explanatory power of the local habitat quantity and management variables was limited. Species richness was highest in patches of semi-natural grassland, second highest in forest edges and lowest in road and field margins surrounded by cultivated fields. Species richness increased with abundance of nectar flowers and margin width, and decreased with increasing soil moisture and within-patch openness. Landscape openness showed a unimodal response with a maximum species richness at intermediate values. Largely the same variables affected species richness of moths and butterflies, but moths appeared to be more sensitive to negative effects of windiness and intensive management and less dependent on abundant flowers and increasing margin width than butterflies. The results highlight the significance of even small patches of semi-natural grasslands and open, sunny forest edges for species richness in typical modern farmland with relatively intensive agriculture. The effectiveness of agri-environment schemes in promoting biodiversity could be increased by directing more efforts to maintenance and restoration of these habitats.

This paper compares the performance of five modelling methods in the prediction of a species distribution, using a data set describing the distribution of the threatened clouded apollo butterfly ( Parnassius mnemosyne ) in south-west Finland. The five statistical techniques included were: generalized linear models (GLM), generalized additive models (GAM), classification tree analysis (CTA), neural networks (ANN) and multiple adaptive regression splines (MARS). The accuracy of the models was examined at three spatial resolutions (1, 25 and 100 ha) by area under the curve (AUC) and kappa statistics. All five modelling techniques had a relatively high discrimination capacity for the occurrence of clouded apollo. Classification tree analysis provided the least robust model performance. The differences between the other methods were small, although GAM and MARS provided marginally the best stability and performance. The most accurate models were developed for the resolutions of 1 ha (highest AUC values) and 25 ha (highest kappa values) and the least accurate models for the resolution of 100 ha. Our work shows that modern modelling techniques can provide useful forecasts of species distributions in unsurveyed parts of landscapes and provide valuable contributions to conservation and management planning. However, the success of applying the new modelling tools can be influenced by the choice of statistical technique and especially of spatial resolution. In conclusion, small changes in the spatial scale may result in a clear decrease in the model performance and thus caution should be exercised when implementing the models and their predictions in practice.

Indicator classifications help us to focus on the most relevant groups of species in monitoring the effects of land use changes on biodiversity. We studied changes in distribution area of 74 butterfly species preferring one of the three common habitats of boreal agricultural landscapes: semi-natural grasslands (35 species), arable field margins (7) and forest edges (32). Using extensive atlas data from four time periods during the last 50 years in Finland, we quantified trends in the occupancy of the species in 10 km grid squares, and classified them into four classes: declining (23), stable (17), increasing (27) and fluctuating (7) species. Trends among the species favouring three habitats were different: 60% of the species of semi-natural grasslands had declined, whereas 86% of the species typical of open field margins had increased. An increase also predominated in species associated with forest edges. Declining and increasing species differed in three ecological characteristics: increasing species were more mobile, utilized a wider range of habitats and, based on their larval host plants, lived in more eutrophic habitats than declining species. Species overwintering as adults showed more positive trends in occupancy than species overwintering as eggs, larvae or pupae. Observed trends in occupancy are in good agreement with long-term changes in land use and habitat availability in Finland: a long-continued decrease in the area of semi-natural grasslands and an increased amount of open forest edges and clearings due to modern forestry during the past 50 years.

Empirical studies have suggested that species richness of grassland insects usually decreases under grazing management. By contrast, grazing has been shown to increase the species density and richness of vascular plants, especially on productive soils. In order to test the suggested differences in response to management between plants and insects, we simultaneously studied species richness of vascular plants and their insect herbivores, butterflies and moths, in 68 semi-natural grasslands with varying grazing intensity and frequency in SW Finland. Species richness of plants and insects was for the first time related to a quantitative measure of disturbance intensity and successional age, mean vegetation height, by using generalized additive models (GAM). The effects of soil nutrients on vegetation height were accounted for by using phosphorus concentration as a productivity surrogate. The results showed that species richness of butterflies and moths peaked in taller vegetation compared with vascular plants, corresponding to a lower disturbance intensity and increasing time since abandonment. These patterns are discussed in the light of two hypotheses, the ‘‘structural diversity hypothesis’’ and ‘‘dynamic equilibrium model’’ of Huston, both suggesting a weaker disturbance tolerance of insects compared with plants. Butterflies and moths which are specialists in their larval host-plant use (monophagous and oligophagous species) preferred lower vegetation (higher disturbances) compared with generalists (polyphagous species), as predicted by Huston’s model. This difference indicates a stronger relationship with plant species richness for specialist than for generalist butterflies and moths. Our results support the application of regionally and temporally varying grazing intensities in grassland conservation management.

Aim To assess the relative importance of climate, biotope and soil variables as well as geographical location for the species richness of plants, butterflies, day-active macromoths and wild bees in boreal agricultural landscapes. Location A total of 68 agricultural landscapes located in southern Finland. Methods Generalized linear mixed models were used to analyse the effects of environmental (climate, biotope and soil) and spatial (latitude and longitude) variables on species richness of four taxa in 136 study squares of 0.25 km2. Using partial regression, the variation in species richness was decomposed into the purely environmental fraction; the spatially structured environmental fraction; and the purely spatial fraction, including variables retained in cubic trend surface regression. Results Species richness of all taxa was positively correlated with temperature. Species richness of plants and butterflies was also positively correlated with the heterogeneity of landscape. The extent of low-intensity agricultural land and forest had a positive effect, and the extent of cultivated field a negative effect on the species richness of these taxa. The effect of soil characteristics on the number of observed species was negligible for all taxa. The greatest part of the explained variation for all taxa was accounted for by the pure effect of geographical location. To a somewhat lesser extent, the species richness of plants, butterflies and bees was also related to the effects of spatially structured environmental variables, and the species richness of macromoths to the effects of environmental variables. Main conclusions Multi-species richness of boreal agricultural landscapes at the scale of 0.25 km2 was associated with the heterogeneity of the local landscape. However, large-scale geographical variation in species richness was also observed, which indicates the importance of climate and geographical location for the taxa studied. These results highlight the fact that, even on a landscape scale, geographical factors should be taken into account in biodiversity studies. Heterogeneous agricultural landscapes, including forest and non-crop biotopes, should be preserved or restored to maintain biodiversity.

The effects of restorative grazing on the abundance of butterfly and moth species were studied in mesic semi-natural grasslands of SW Finland differing in management history: (1) old continuously grazed, (2) restored (with ca 5 years of reinitiated grazing), and (3) abandoned former pastures. Generalized linear modelling of species abundances and indicator species analysis produced qualitatively similar results. Only three species (Polyommatus icarus, Lycaena hippothoe and Camptogramma bilineatum) were most abundant in old pastures, whereas 12 species (Polyommatus semiargus, Polyommatus amandus, Brenthis ino, Aphantopus hyperantus, Scopula immorata, Idaea serpentata, Scotopteryx chenopodiata, Epirrhoe alternata, Cybosia mesomella, Polypogon tentacularius, Hypena proboscidalis and Cryptocala chardinyi) were most abundant in abandoned pastures. None of the old-pasture species had become more abundant in restored pastures. Three species, Epirrhoe hastulata, Xanthorhoe montanata and Chiasmia clathrata, occurred equally abundantly in abandoned and in restored pastures indicating a slow progress of restoration. Species associated with old pastures differed from species associated with abandoned pastures in their recent distributional changes in Finland. The species of old pastures showed decreasing trends, whereas those of abandoned pastures showed mainly increasing trends in their distribution. In five out of 11 species, the preferred successional stage differed markedly between this study and previous studies conducted in Central Europe. We conclude that (1) ca 5 years of restorative grazing in mesic grasslands has been insufficient for the colonisation of old-pasture species in the restored sites, (2) different management intensities are needed regionally for the maintenance of grassland insect diversity and (3) application of the knowledge on successional preferences of different species in conservation management, even in climatically similar regions, should be made with caution.

We studied movements of the noctuid moths Xestia speciosa and X. fennica in a fragmented forest landscape including old-growth spruce forest corridors in eastern Finland. We individually marked and released 1,796 adults of the habitat generalist X. speciosa and 683 individuals of X. fennica, which prefers old-growth spruce forests. Moths were recaptured with 60 sugar-bait traps that were placed within habitat corridors, in the non-habitat matrix and in surrounding old-growth forest patches. Both species favoured the corridors during their movements and tended to avoid entering the matrix. We analysed recapture rates and movements of the recaptured moths. Results suggest that X. speciosa moves longer distances than X. fennica. Though corridors clearly canalized movements by both species, the impact of old-growth forest corridors at the larger landscape scale was less clear in X. fennica. Movement behaviour of the two sexes differed more than that of the two species.

Bayesian belief network (Fully Connected Belief Networks, FC BeNe) was used to estimate uncertainty in the functioning of established buffer zones in Finland. Four experts in the field of water protection and four in biodiversity were asked to assess the roles of 25 key variables involved in the functioning of buffer zones. The matrix comprised five levels of information: field properties, buffer zone properties, management measures, site data and concerns. The eight experts were asked to estimate probability distributions and causal relationships between the 25 variables, which included in particular erosion, particle bound P, dissolved P, and plant, insect and bird species diversity. Any of the three phases of the analysis; prior distributions, links and posterior distributions are end products which are usable as such. The highest uncertainties were attributed to management measures, e.g. sowing leys, meadow plants, trees and/or bushes and soil removal from the upper end of the field in order to create nutrient-poor meadows. Uncertainties were also seen in P-status, fertilizer and manure changes, transport of dissolved phosphorus, particle bound phosphorus, bird species diversity and landscape. All experts thought that erosion affects particle bound phosphorus, but there was wide deviation in the link strength values, 0.05–0.7, which clearly reflects a lack of knowledge. Two of the experts assumed particle bound P to become partly dissolved, the other two did not. The effect of buffer zones on transport of dissolved phosphorus was not clear. The link strength direction of the variables grazing and rotational grazing to dissolved P varied between the experts. According to the expert evaluations, positive impacts caused by buffer zones were probable in erosion, and in plant and insect species diversity, which is in agreement with existing empirical studies. Experts expected plant height to be beneficial to bird species diversity, but disagreed as to the effect of plant height on plant and insect species diversity. Biodiversity experts considered that steep slopes produced more erosion, more leaching, and hence more patches for biodiversity contrary to water pollution.

A decrease of habitat and species diversity in agricultural landscapes, mainly as a result of the decline of semi-natural grasslands, has been shown in several studies. However, no studies have linked the effects of decrease of grassland management with landscape structure and plant and bird species diversity on the landscape scale in a spatial grid system. In this study we examined the differences in the present habitat and species diversity (number of total and rare plant and bird species) among agricultural landscapes differing in their management history. We compared areas of 0.25 km2 (n = 34) with different grazing history in the Rekijoki river valley, SW Finland. The grazed area decreased to one fifth over 30 years (1960–1990) in our study area. The earlier interconnected network of grazed patches was disrupted, resulting in an isolated grazing pattern. There were statistical differences in the habitat structure and plant species diversity between the landscapes with different management histories, but no difference in bird diversity was observed. The number of rare plant species/0.25 km2 was 45% less in areas of 20–40 years of abandonment compared to squares with continuously grazed patches. The results address the importance of grazing management for maintaining heterogeneous habitat mosaics and plant diversity on the landscape scale.

Context: Agricultural transformation and increased land use intensity often lead to simplified landscapes and biodiversity loss. For animals, one possible mechanism underpinning biodiversity loss in agricultural landscapes is the disruption of movements. The disruption of movements may explain, for example, why butterfly communities in agricultural landscapes are often dominated by generalist species with high mobility.Objectives: Here, we investigated how the movement patterns of butterflies characterised by different levels of mobility changed along a gradient of agricultural land use intensity.Methods: To this end, we studied 15 landscapes in low-intensity farmland in Central Romania, measuring 10 ha each and covering a gradient of landscape heterogeneity and woody vegetation cover. In these landscapes, we tracked movements of 563 individuals of nine butterfly species.Results: Our findings showed that overall movement activities differed significantly between species, corresponding well with expert-derived estimates of species-specific mobility. Interestingly, species of low and high mobility responded in opposite ways to increasing levels of landscape heterogeneity. In relatively simple landscapes, the movement patterns of low and high mobility species were similar. By contrast, in complex landscapes, the flight paths of low-mobility species became shorter and more erratic, whereas the flight paths of high-mobility species became longer and straighter. An analysis of the land covers traversed showed that most species avoided arable land but favoured the more heterogeneous parts of a given landscape.Conclusions: In combination, our results suggest that non-arable patches in agricultural landscapes are important for butterfly movements, especially for low-mobility species.

Aim We tested the usefulness of satellite based remote sensing data and geographical information system (GIS) techniques (1) in explaining the observed distribution of the threatened clouded apollo butterfly (Parnassius mnemosyne) and (2) in predicting the occurrence of the butterfly in two independent test areas with different landscape structure. Location The three study areas are located along the rivers Rekijoki and Halikonjoki in a boreal agricultural landscape in south-western Finland (60°40′ N; 23°20′ E). Methods Landsat satellite images were used to generate habitat maps of the three study areas. Topographical variables were calculated from a digital elevation model. These data were used to construct a multiple logistic regression model fitted with the observed occurrence of clouded apollo in 126 grid squares of 0.25 km2 within an area of 31.5 km2 (model building area). The parameterized model was used to predict the occurrence of the butterfly in an adjacent test area with a similar landscape structure as in the model building area, as well as in a more distant test area with a more fragmented pattern of semi-natural grassland. Results In the model building area probability of clouded apollo occurrence increased with connectivity of semi-natural grassland, cover of deciduous forest, cover of semi-natural slope grassland and topographical heterogeneity. The model accuracy was high, the correct classification rate being 98.4% overall and 95.0% for the butterfly presence squares. In both test areas the overall correct classification of the model prediction was high (c. 92%). However, in predicting the actual butterfly presence squares the model succeeded substantially better in the adjacent than in the distant test area (correct classification rates 91.3% and 66.7%, respectively). Main conclusions The results showed that the distribution of a habitat specialized butterfly may be quite successfully explained and predicted based on pure satellite imagery and topographical data. Nevertheless, the decrease of accuracy of the model prediction when applied to a different landscape structure than the one in which the model was parameterized suggests that the useful application of such models is limited by the environmental variability of the original model building data.

Recent studies on the determinants of distribution and abundance of animals at landscape level have emphasized the usefulness of the metapopulation approach, in which patch area and habitat connectivity have often proved to explain satisfactorily existing patch occupancy patterns. A different approach is needed to study the common situation in which suitable habitat is difficult to determine or does not occur in well-defined habitat patches. We applied a landscape ecological approach to study the determinants of distribution and abundance of the threatened clouded apollo Parnassius mnemosyne butterfly within an area of 6 km2 of agricultural landscape in south-western Finland. The relative role of 24 environmental variables potentially affecting the distribution and abundance of the butterfly was studied using a spatial grid system with 2408 grid squares of 0.25 ha, of which 349 were occupied by the clouded apollo. Both the probability of butterfly presence and abundance in a 0.25 ha square increased with the presence of the larval host plant Corydalis solida, the cover of semi-natural grassland, the amount of solar radiation and spatial autocorrelation in butterfly occurrence. Additionally, butterfly abundance increased with overall mean patch size and decreased with maximum slope angle and wind speed. Two advantages of the employment of a spatial grid system included the avoidance of a subjective definition of suitable habitat patches and an evaluation of the relative significance of different components of habitat quality at the same time with habitat availability and connectivity. The large variation in habitat quality was influenced by the abundance of the larval host plant and adult nectar sources but also by climatological, topographical and structural factors. The application of a spatial grid system as used here has potential for a wide use in studies on landscape-level distribution and abundance patterns in species with complex habitat requirements

The effects of inbreeding on fitness and themaintenance of genetic load in metapopulationsof the endangered Glanville fritillarybutterfly (Melitaea cinxia) were examinedin four laboratory experiments. In FinlandM. cinxia occurs as a large metapopulationconsisting of small local populations with fastturnover, whereas in southern France thespecies has a more continuous populationstructure. In the experiments, we compared theperformance of crosses between full sibs,crosses between members of different familieswithin populations, and crosses betweenindividuals from different populations. Theseexperiments were replicated using insects fromtwo different regions, Finland and southernFrance, between which the frequency of naturalinbreeding should differ substantially becauseof differing population structure. In Finnishbutterflies, the rate of successful mating waslower among insects derived from small thanfrom large natural populations, probablyreflecting the effect of past inbreedinghistory. Mating between full sibs lowered egghatching rate in all experiments. Thisreduction of egg hatching rate was more severeamong French butterflies with a more continuouspopulation structure than among Finnishbutterflies with small naturally fragmentedpopulations and with a history of repeatedrounds of inbreeding in the past. This resultsuggests that recurrent inbreeding has led topartial purging of deleterious recessives fromthe Finnish metapopulation. Nonetheless,substantial genetic load still remains in thismetapopulation, and we discuss possible reasonswhy this should be the case.

We studied host plant abundance, host use, and oviposition preference in metapopulations of the butterfly Melitaea cinxia within an area of 3500 km2 in the Aland islands, southwestern Finland. In the study area, M. cinxia has -400 small local populations on dry meadows with the larval host plants, Plantago lanceolata and Veronica spicata. Plantago lanceolata occurs in practically all meadows otherwise suitable for the butterfly, whereas the distribution of V. spicata is largely restricted to the northwestern part of the study area. Based on observations of 6500 prediapause larval groups during 1993-1996, we document spatial variation in host plant use in relation to their abundance (electivity). The fraction of larval groups found on V. spicata increased disproportionally with the relative cover of V. spicata in the habitat patches. Additionally, the probability of Veronica use in a population increased with increasing number of larval groups found on Veronica in the surrounding populations but decreased with increasing use of Plantago in the neigh- borhood. This regional effect on host use at the scale of migrating butterflies could be caused either by spatial variation in the insect (in either preference or performance) or by spatial variation in plants (in resistance to attack by the butterflies). To study the first possibility, we conducted oviposition preference experiments using butterflies from five metapopulations located 2-55 km from each other and characterized by differences in host plant availability and host use. We found clear genetic differences in oviposition preference between the five metapopulations consistent with the observed host use patterns in the field. We conclude that the spatial host use patterns of M. cinxia in the study area are driven both by direct effects of local host abundance and by indirect effects mediated through metapopulation-level adaptation to the regionally more abundant host plant.

Lepsämänjoki LTSER (long term social ecological research platform) kuuluu kahdeksan muun erilaisia ekosysteemityyppejä edustavan verkoston kanssa vuonna 2007 perustettuun Suomen LTSER- konsortioon (FinLTSER: http://www.ymparisto.fi/default.asp?contentid=257172&lan=FI). FinLTSER puolestaan on samana vuonna hyväksytty kv. ILTER -verkostoon jäseneksi (http://www.ilternet.edu/). LTSER toiminnan perusajatus on luoda ja ylläpitää ekosysteemitutkimuksen infrastruktuureja, joissa pitkäaikainen ja seuranta-aineistoihin perustuva tutkimus kohdistuu ns. ydinalueelle. Tällainen ydinalue on maantieteellisesti määritelty ekosysteemialue, jossa verkoston tutkimusryhmät tuottavat pitkäaikaista, julkista ja hyvin dokumentoitua seurantaja tutkimustietoa sosioekologisista ekosysteemin tilaan ja muutokseen sekä muutosta ohjaaviin voimiin liittyvistä muuttujista. LTSER- verkoston tulisi mahdollistaa monitieteinen ja tieteidenvälinen sosioekologinen tutkimus, ja sen tulisi tuottaa laadukasta tutkimusdataa kv. tutkimusyhteisön käyttöön. Lepsämänjoki LTSER on keskeisten maatalousekosysteemien tilasta ja muutoksesta kiinnostuneiden tutkimuslaitosten ja –ryhmien verkosto. Se on avoin yhteenliittymä, joka pyrkii kehittämään julkista ja yleishyödyllistä yhteistyötä ja infrastruktuuria maatalousympäristön monitieteiseen tutkimukseen. Verkoston ydinalue on Lepsämänjoen maataloudellinen valuma-alue, joka suurimmaksi osaksi kuuluu Uusimaalaisen Nurmijärven kunnan alueeseen noin 30 km Helsingistä luoteeseen (60° 23' 60° 28' N, 24° 31' 24° 43' E). Se on topografialtaan laakea 213 km² suuruinen alue, jossa harjoitetaan Etelä-Suomen savikoille ominaista peltoviljelyvaltaista maataloutta. Alueen pohjoisosassa on useita vihannesviljelyyn keskittyneitä tiloja. Alue on kaupungin läheistä maaseutua, jolle muualla työskentelevien haja-asutus leviää, ja jonka eteläosassa sijaitseva Klaukkalan taajama on kasvussa. Lepsämänjoen valuma-alueelta on parhaimmillaan jo vuosikymmenten ajalta biofysikaalisiin ympäristömuuttujiin liittyviä tutkimusaineistoja: jokiveden laatu, maatalouden ravinne- ja kiintoaineskuormitus, maataloudellinen maankäyttö, maatalouden ravinnetaseet, maalajit ja topografia, alue-ekologinen monimuotoisuus, putkilokasvien, perhosten ja peltolintujen lajimonimuotoisuus. Verkoston eri tutkimusryhmät ovat toisistaan riippumatta koonneet em. aineistoja eri seurannoissa ja tutkimus- ja kehityshankkeissa. Lepsämänjoki LTSER-verkoston tavoite on LTSER-konseptin mukaisesti verkostoitumisen avulla kehittää tutkimuksen infrastruktuuria, parantaa seuranta-aineistojen saatavuutta ja laatua sekä edistää ekologisen, ympäristöja yhteiskunnallisen tutkimuksen integraatiota. Tiedustelut voi osoittaa verkoston koordinaattorille (juha.helenius@helsinki.fi).

It has been proposed that inbreeding contributes to the decline and eventual extinction of small and isolated populations1,2. There is ample evidence of fitness reduction due to inbreeding (inbreeding depression) in captivity3,4,5,6,7 and from a few experimental8,9 and observational field studies10,11, but no field studies on natural populations have been conducted to test the proposed effect on extinction. It has been argued that in natural populations the impact of inbreeding depression on population survival will be insignificant in comparison to that of demographic and environmental stochasticity12,13. We have now studied the effect of inbreeding on local extinction in a large metapopulation14 of the Glanville fritillary butterfly (Melitaea cinxia)15. We found that extinction risk increased significantly with decreasing heterozygosity, an indication of inbreeding6, even after accounting for the effects of the relevant ecological factors. Larval survival, adult longevity and egg-hatching rate were found to be adversely affected by inbreeding and appear to be the fitness components underlying the relationship between inbreeding and extinction. To our knowledge, this is the first demonstration of an effect of inbreeding on the extinction of natural populations. Our results are particularly relevant to the increasing number of species with small local populations due to habitat loss and fragmentation16.

Long-range, seasonal migration is a widespread phenomenon among insects, allowing them to track and exploit abundant but ephemeral resources over vast geographical areas. However, the basic patterns of how species shift across multiple locations and seasons are unknown in most cases, even though migrant species comprise an important component of the temperate-zone biota. The painted lady butterfly Vanessa cardui is such an example; a cosmopolitan continuously-brooded species which migrates each year between Africa and Europe, sometimes in enormous numbers. The migration of 2009 was one of the most impressive recorded, and thousands of observations were collected through citizen science programmes and systematic entomological surveys, such as high altitude insect-monitoring radar and ground-based butterfly monitoring schemes. Here we use V. cardui as a model species to better understand insect migration in the Western Palaearctic, and we capitalise on the complementary data sources available for this iconic butterfly. The migratory cycle in this species involves six generations, encompassing a latitudinal shift of thousands of kilometres (up to 60 degrees of latitude). The cycle comprises an annual poleward advance of the populations in spring followed by an equatorward return movement in autumn, with returning individuals potentially flying thousands of kilometres. We show that many long-distance migrants take advantage of favourable winds, moving downwind at high elevation (from some tens of metres from the ground to altitudes over 1000 m), pointing at strong similarities in the flight strategies used by V. cardui and other migrant Lepidoptera. Our results reveal the highly successful strategy that has evolved in these insects, and provide a useful framework for a better understanding of long-distance seasonal migration in the temperate regions worldwide.

The incidence function model is derived from a linear first-order Markov chain of the presence or absence of a species in a habitat patch. The model can be parameterized with “snapshot” presence/absence data from a patch network. Using the estimated parameter values the Markov chain can be iterated in the same or in some other patch network to generate quantitative predictions about transient metapopulation dynamics and the stochastic steady state. We tested the ability of the incidence function model to predict patch occupancy using extensive data on an endangered butterfly, the Glanville fritillary (Melitaea cinxia) Parameter values were estimated with data collected from a 50-patch network in 1991. In 1993 we surveyed the entire geographic range of the species in Finland, within an area of 50 × 70 km2, with 1502 habitat patches (dry meadows) of which 536 were occupied. Model predictions were generated for the 1502 patches and were compared with the observed pattern of occupancy in 1993. The model predicted patch occupancy well in more than half of the study area, but prediction was poor for one quarter of the area, probably because of regional variation in habitat quality and because metapopulations may have been perturbed away from the steady state. The incidence function model provides a practical tool for making quantitative predictions about metapopulation dynamics of species living in fragmented landscapes.

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. Keywords: Agri-environmental schemes, ecological contrast, ecosystem services, landscape context, land-use intensity, pollinators.

The previously unknown female of the noctuid moth Hyptioxesta magadanica (Kononenko, 1981) is described and compared with other Hyptioxesta species. The H. magadanica female is brachypterous, unlike the females of the other two species included in the genus. The female genitalia of H. magadanica and the adults of all three species are illustrated. Notes on the flight behaviour of the adults of H. magadanica and H. penthima (Erschoff, 1870) are given and their habitats are illustrated.

THE worldwide loss and fragmentation of natural habitats1has led to considerable theory on metapopulation dynamics2a¤-8. One modelling approach, using structured population models9,10, predicts that metapopulations in which local dynamics are affected by migration may have alternative stable equilibria11a¤-17. We have tested this prediction with extensive data on the butterfly Melitaea cinxia18,19. Here we show that the probability of local extinction decreases with increasing population size and increasing immigration rate, and that local populations tend to be larger in regions with higher density of extant populations19, results consistent with model assumptions and predictions13,17. Our results exhibit a bifurcation pattern indicating multiple equilibria14, with a strikingly bimodal distribution of the fraction of occupied habitat in 65 semi-independent patch networks. These results help to explain observations of species occupying either most, or very little, of the suitable habitat in well-connected patch networks14,20,21. Metapopulations with multiple equilibria may collapse unexpectedly to extinction even in landscapes degrading only slowly. Multiple equilibria make it difficult to predict the occurrence of species in fragmented landscapes.

International audience

There is a lack of quantitative syntheses of fragmentation effects across species and biogeographic regions, especially with respect to species life-history traits. We used data from 24 independent studies of butterflies and moths from a wide range of habitats and landscapes in Europe and North America to test whether traits associated with dispersal capacity, niche breadth and reproductive rate modify the effect of habitat fragmentation on species richness. Overall, species richness increased with habitat patch area and connectivity. Life-history traits improved the explanatory power of the statistical models considerably and modified the butterfly species-area relationship. Species with low mobility, a narrow feeding niche and low reproduction were most strongly affected by habitat loss. This demonstrates the importance of considering life-history traits in fragmentation studies and implies that both species richness and composition change in a predictable manner with habitat loss and fragmentation.

There is a lack of quantitative syntheses of fragmentation effects across species and biogeographic regions, especially with respect to species life-history traits. We used data from 24 independent studies of butterflies and moths from a wide range of habitats and landscapes in Europe and North America to test whether traits associated with dispersal capacity, niche breadth and reproductive rate modify the effect of habitat fragmentation on species richness. Overall, species richness increased with habitat patch area and connectivity. Life-history traits improved the explanatory power of the statistical models considerably and modified the butterfly species-area relationship. Species with low mobility, a narrow feeding niche and low reproduction were most strongly affected by habitat loss. This demonstrates the importance of considering life-history traits in fragmentation studies and implies that both species richness and composition change in a predictable manner with habitat loss and fragmentation.

Bryodema tuberculata (Fabricius) was discovered as a species new to Finland at St: Säkylä, Säkylänharju, where it occurred sparsely together with Psophus stridulus (Linnaeus). The habitat on a SW-facing esker slope is described, and the spatial distribution of the two species is examined. Preliminarily estimates of the population density, aggregation and vagility are calculated for P. stridulus. The biogeography and conservation biology of the species are discussed.

Metapopulation theory predicts that species richness and total population density of habitat specialists increase with increasing area and regional connectivity of the habitat. To test these predictions, we examined the relative contributions of habitat patch area, connectivity of the regional habitat network and local habitat quality to species richness and total density of butterflies and day-active moths inhabiting semi-natural grasslands. We studied butterflies and moths in 48 replicate landscapes situated in southwest Finland, including a focal patch and the surrounding network of other semi-natural grasslands within a radius of 1.5 km from the focal patch. By applying the method of hierarchical partitioning, which can distinguish between independent and joint contributions of individual explanatory variables, we observed that variables of the local habitat quality (e.g. mean vegetation height and nectar plant abundance) generally showed the highest independent effect on species richness and total density of butterflies and moths. Habitat area did not show a significant independent contribution to species richness and total density of butterflies and moths. The effect of habitat connectivity was observed only for total density of the declining butterflies and moths. These observations indicate that the local habitat quality is of foremost importance in explaining variation in species richness and total density of butterflies and moths. In addition, declining butterflies and moths have larger populations in well-connected networks of semi-natural grasslands. Our results suggest that, while it is crucial to maintain high-quality habitats by management, with limited resources it would be appropriate to concentrate grassland management and restoration to areas with well-connected grassland networks in which the declining species currently have their strongest populations.

Hankkeessa pyrittiin tuottamaan arvio Suomessa v. 2000 - 2006 käytössä olleen ympäristötukijärjestelmän vaikuttavuudesta ympäristöön. Työssä arvioitiin yksittäisiä toimenpiteitä sekä järjestelmää kokonaisuutena. Järjestelmän toimivuutta peilattiin sille asetettuja tavoitteita vastaan ja etsittiin parannusmahdollisuuksia. Toimenpiteiden vesiensuojelullisen kustannustehokkuuden lisäksi tarkasteltiin monimuotoisuuskustannustehokkuutta ja kehitettiin siihen liittyvää arviointimenetelmää. Hankkeessa myös kehitettiin menetelmää toimenpiteiden ympäristövaikutusten yhdennettyyn arviointiin. Vesiensuojelullisen tehon lisäämiseksi lannoitukseen ja kasvipeitteisyyteen liittyviä toimenpiteitä tulee edelleen tehostaa ja kohdentaa. Varsinkin lannan käyttöä tulee tehostaa. Väkilannoitteiden pintalannoituksesta tulisi pystyä luopumaan ja lannan levityksessä nopea multaus on tärkeää. Kasvipeitteisyyden lisääminen maan etelä- ja länsiosissa ja varsinkin jyrkillä rantapelloilla on eroosion torjunnan kannalta tärkeää. Korkeita maan helppoliukoisen fosforin pitoisuuksia on alennettava. Luonnon monimuotoisuuden edistämisen kannalta olisi oleellista kehittää perustukeen kuuluva laajasti toteutettava ja vaikuttava toimenpide. Pientareet ja suojakaistat –toimenpiteen merkitys monimuotoisuuden edistämisessä paranisi, jos se sisältäisi vesistöjen reunojen lisäksi myös muita reuna-alueita. Taantuneen ja uhanalaisen maatalousalueiden lajiston säilyttämiseksi perinnebiotooppien erityistuki on periaatteiltaan hyvin toimiva tukimuoto. Hoidettavien perinnebiotooppien määrää tulee edelleen lisätä koko maassa.

Viljelykiertojen yksipuolistuminen on vähentänyt peltolajiston monimuotoisuutta. Viljelykiertoja voitaisiin monipuolistaa sisällyttämällä niihin viherkesantoja. Nykyisin vallitsevat viherkesannot eivät ole monimuotoisuuden kannalta kaikkein parhaita, sillä ne perustetaan voimakkaasti kilpailevilla monivuotisilla nurmikasveilla. Peltoluonnon monimuotoisuuden kannalta edullisempia olisivat heikommin kilpailevat kasvustot. Tämän tutkimuksen tavoitteena oli selvittää, millaiset kesannot olisivat lajiston monimuotoisuuden kannalta parhaita.Tutkimuksessa esitellään vuonna 2003 perustetun nelivuotisen kenttäkokeen tuloksia vuodelta 2004. Tutkimuskohteina olivat kasvit (kartoitus) ja pölyttäjähyönteiset (linjalaskennat), tuholaiset ja niiden luontaiset viholliset (kuoppapyydykset ja kelta-ansat) sekä lintujen siemenravinto (maanäytteet) ja hyönteisravinto (haavinnat ja kelta-ansat). Kokeen käsittelyt olivat kesannon ikä (1 tai 2 vuotta), perustamismenetelmä (kylvö suojaviljaan vs. kylvö ilman suojaviljaa) ja siemenseos (voimakkaasti kilpaileva timoteipuna- apila-nurminataseos sekä heikommin kilpaileva nurmirölli-lampaannataseos). Viherkesantoja verrattiin yksinomaan viljaa sisältävään viljelykiertoon sekä sänkikesantoon.Pölyttäjähyönteisten ja kasvien lajimäärään vaikuttivat siemenseos ja kesannon ikä kesannon perustamistapaa enemmän. Kummassakaan eliöryhmässä ei lajimäärän havaittu poikkeavan siemenseosten välillä ensimmäisen vuoden kesannoilla, mutta toisen vuoden kesannoilla nurmirölli-lampaannatakesantojen lajimäärä oli apila-nurminatakesantoja korkeampi. Sänkikesannoilla saavutettiin jo ensimmäisenä kesänä yhtä suuri kasvien ja pölyttäjien lajimäärä kuin nurmirölli-lampaannataruuduilla kahdessa vuodessa.Lintujen siemenravinnon tuottoon vaikuttivat kesannon perustamistapa, ikä ja siemenseos. Siemenseokset eivät eronneet ensimmäisenä vuonna, mutta toisen vuoden nurmirölli-lampaannatakesannoilla rikkakasvien siementuotanto oli suurempi. Yksivuotisten kesantojen runsain laji oli pihatähtimö. Toisen vuoden kesannoilla runsaimpia lajeja olivat peltosaunio ja peltolemmikki. Lintujen hyönteisravinnossa tärkeimpiä ryhmiä olivat kärpäset ja sääsket. Kärpäsiä oli runsaasti toisen vuoden nurmirölli-lampaannataja sänkikesannossa sekä ohrakasvustoissa. Sen sijaan sääskien määrissä ei havaittu eroja kasvustojen välillä. Luteita ja kaskaita oli eniten suojaviljaan kylvetyssä puna-apila-nurminatakesannossa, kun taas loispistiäiset viihtyivät nurmirölli-lampaannata- ja sänkikesannoissa. Kasvuston ikä oli tärkein tuholaisten ja niiden luontaisten vihollisten määrään vaikuttava tekijä: tuholaisten (kahukärpänen ja aaltojuovakirppa) määrä väheni ja luontaisten vihollisten (hämähäkit) määrä kasvoi kesannon iän myötä.Lyhytaikaisten viherkesantojen avulla voidaan lisätä eri eliöryhmien lajiston monimuotoisuutta. Kesantojen paremmuus siemenseoksen, iän ja perustamistavan suhteen riippuu eliöryhmästä.

This chapter discusses butterfly metapopulation dynamics. The metapopulation concept is swiftly spreading into common usage in population and conservation biology. The term “metapopulation” itself is not new, as it was coined by Richard Levins, 25 years ago. It took 20 years before biologists at large began to employ it. The model is based on a generalized incidence function and it provides a simple yet realistic and practical means of modeling real metapopulations. Melitaea cinxia is one of the many European butterflies that have declined during the past decades. More than half of the species not forming local populations failed also to satisfy the second condition, because they have large “mainland” populations. During the past 10 years the metapopulation approach has been applied in several butterfly studies in both North America and Europe. Migration between habitat patches is a key process in metapopulation dynamics. It is not generally agreed that metapopulation dynamics in the sense described in this chapter are often critical for long-term persistence of butterflies and other taxa. It is difficult to disagree about rampant environmental changes, and it is equally clear that many populations have been exterminated because the habitat became unsuitable. Melitaea cinxia may be exceptional, but until a score of other equally comprehensive studies have been completed, there is no reason to rush to a general conclusion.

The Allee effect a decrease in population growth rate at low density - may be produced by several mechanisms including difficulty in finding mates at low densities. We present evidence for the Allee effect in natural populations of an endangered butterfly. the Glanville fritillary (Melitaea cinxia) and for two mechanisms that cause it. Specifically. we show that emigration rate increases and the fraction of mated females decreases with decreasing local density. We then demonstrate a connection between mating success and population growth rate and more generally, slightly reduced reproductive success in the smallest butterfly populations in an extensive data set gathered over four years. The Allee effect increases the significance of the rescue effect in metapopulations, and thereby the potential for alternative stable states in metapopulation as well as in local dynamics.

1. We studied factors affecting emigration and immigration behaviour in the butterfly Melitaea cinxia by releasing 882 newly emerged marked butterflies into 16 habitat patches in a network of 64 empty patches on an isolated island (area 1.6 km 2 ). 2. Of the 363 butterflies that were recaptured at least once, 40% were recorded in a new patch during their lifetime. Females emigrated earlier and moved further away than males. One-third of males appeared to remain permanently in, whereas females gradually drifted away from, the release patch. 3. High density of butterflies, great abundance of flowers, and large patch area decreased emigration, whereas open landscape around the patch increased emigration. Females that emigrated were on average larger than females that stayed in the patch of release. 4. In total, 152 immigrants were recorded in 32 patches. Numbers of immigrants increased with patch area and abundance of flowering plants. 5. Results on emigration suggest that conserving an isolated butterfly population is more successful in an area with physical barriers to migration than in an open landscape. The possible tendency of butterflies to leave a patch with low density should be taken into consideration in introductions of butterflies to empty habitat patches. 6. Results on immigration indicate the significance of nectar sources and patch size in successful colonization of empty habitat patches.

We describe an extensive metapopulation study on the Glanville fritillary Melitaea cinxia, in a network of 1502 discrete habitat patches, comprising the entire distribution of this butterfly species in Finland. A thorough survey of the easily detected larval groups revealed a local population in 536 patches (dry meadows). We demonstrate that this system satisfies the four necessary conditions for a species to persist in a balance between stochastic local extinctions and recolonizations. Patterns of patch occupancy support several qualitative and quantitative model predictions. With decreasing regional density and average area of habitat patches, the butterfly occurs in a diminishing fraction of suitable habitat. To our knowledge, this is the first conclusive demonstration, based on a comparison of many conspecific metapopulations, of declining habitat occupancy and hence of increasing threat to survival caused by increasing habitat fragmentation

Local extinction of species can occur with a substantial delay following habitat loss or degradation. Accumulating evidence suggests that such extinction debts pose a significant but often unrecognized challenge for biodiversity conservation across a wide range of taxa and ecosystems. Species with long generation times and populations near their extinction threshold are most likely to have an extinction debt. However, as long as a species that is predicted to become extinct still persists, there is time for conservation measures such as habitat restoration and landscape management. Standardized long-term monitoring, more high-quality empirical studies on different taxa and ecosystems and further development of analytical methods will help to better quantify extinction debt and protect biodiversity.