Many of the European butterfly species have declined rapidly over the past decades. The cause is thought to be habitat loss due to factors such as increased tree cover, afforestation and intensified agriculture. I analyzed nation-wide data on butterfly occurrences in Sweden, to explore whether occurrences of individual species, grassland dependent species, grassland specialists, red-listed species, and moths, have increased or declined over a period of five years. I found that four species had significantly declined and eight had increased. The results were in accordance with other finds from Sweden, as well as from the UK, regarding the declining species. In contrast, the results regarding the increasing species only partly confirmed previous studies. I also found that grassland specialists and red-listed species had increased, possibly reflecting the fact that Sweden has a relatively large amount of boreal landscapes containing patches of clear-cuts and semi-natural grasslands.

京都大学 / 0048 / 新制・課程博士 / 博士(農学) / 甲第20428号 / 農博第2213号 / 新制||農||1048(附属図書館) / 学位論文||H29||N5049(農学部図書室) / 京都大学大学院農学研究科森林科学専攻 / (主査)教授 井鷺 裕司, 教授 柴田 昌三, 教授 神﨑 護 / 学位規則第4条第1項該当 / Doctor of Agricultural Science / Kyoto University / DFAM

Semi-natural grasslands are species-rich and one of the most threatened habitats in Europe, since land-use changes have led to reduced area of grassland. Appropriate management practices like grazing or mowing is needed to maintain the conservation values and species-richness of semi-natural grasslands. However, few studies have investigated which of grazing or mowing is most appropriate. Furthermore, almost no studies have investigated which mowing technique is best for the conservation value of grassland flora. The aim of this study was to determine which management practice of grazing and mowing, and which mowing technique, has the most positive effect on grassland flora. Data from two long-term trials were evaluated: one compared the effect of grazing and mowing in eleven sites in southern Sweden during at least twelve years; the other compared the effect of the knife mower and grass trimmer at different cutting heights in one site during twelve years. Meta-analysis was used, based on the odds for a plant record being an indicator species, using eight different indicator systems of classification of grassland plants. Over time, results show increasing odds of finding indicators of good management and no change in odds of finding indicators of lack of management in mowed compared to grazed plots. There were no differences in the odds of finding any indicator species for any of the mowing techniques. Hence, to maintain the conservation values of semi-natural grasslands, mowing is the better management practice compared to grazing. Mowing using a knife mower or grass trimmer has similar effects, and can both be recommended.

Changed management of semi-natural grasslands is thought to be one important factor for explaining the decline of butterfly populations in Sweden and the rest of Europe. This study explores how vegetation height, variation in vegetation height and flower abundance can help predict the occurrence of butterfly species in semi-natural grasslands in southern Sweden. My study is based on data collected by a national environmental monitoring programme (NILS) during 2006-2010. Generalized linear models showed that all three explanatory variables significantly affected 26 of the 41 species of butterflies studied. The study also investigated preferences for three different systems for grouping species but did not find differences among groups. Several of the species would most likely benefit from variation in grazing pressure or rotational grazing as well as flower-rich grasslands. The results may also help when aiming management at the preservation of individual species.

Habitat type has been suggested to be a major factor contributing to differencesin plant trait distribution of grassland habitats. Land use changes in agricultural landscapes have affected the available habitats and the dispersal ability of plants, which may effect plant trait diversity of agricultural landscapes. Little is also known about the effects of landscape openness on plant trait diversity. This study analysed differences in plant traits between different semi-natural grassland habitats in agricultural landscapes in four different regions in Sweden: Skåne, Södermanland, Gävleborg, and Norrbotten. The following research questions were used: (1) How does landscape openness (the amount of open andarable land found in a landscape) affect plant trait values collected from a new database in semi-natural grassland habitats in agricultural landscapes? (2) How does the type of habitat affect plant trait values in semi-natural grassland habitats in agricultural landscapes? (3) How does geographical location in Sweden affect plant trait values in semi-natural grassland habitats in agricultural landscapes? Overall 12 landscapes in each region were surveyed for plant data using 20 sample plots in each landscape. Trait values for biodiversity relevance, nectar production, nitrogen, phosphorus, grazing/mowing, soil disturbance, longevity, pollinator dependence, and seed dispenser were assigned for each plant species based on an external database, and average trait values were calculated for each of the studied traits in each sample. Kruskal-Wallis test andANOVA were performed on average trait values to identify differences between each habitat types and regions. Besides the effect of habitat type, the effect of openness in the landscape on the chosen traits was analysed with Spearman’s and Pearson’s correlations. The results revealed differences between habitat types in almost all studied traits: grazed habitats had plants with higher biodiversity relevance but lower nectar production. Differences were also found between the southern and northern regions. More open landscapes had plants with higher biodiversity relevance as well as higher tolerance for both nitrogen and phosphorus. Less open landscapes had higher tolerance for grazing/mowing and higher nectar production. The results of this study therefore support earlier findings of the importance of habitat in plant trait distribution of grassland habitats.

1. Seed bank and seed rain represent dispersal in time and space. They can be important sources of diversity in the rural landscape, where fragmented habitats are linked by their histories. 2. Seed bank, seed rain and above-ground vegetation were sampled in four habitat types (abandoned semi-natural grassland (ABA), grazed former arable field (FAF), mid-field islet (MFI) and grazed semi-natural grassland (SNG)) in a rural landscape in southern Sweden, to examine whether community patterns can be distinguished at large spatial scales and whether seed bank and seed rain are best explained by current, past or intended future vegetation communities. 3. We counted 54 357 seedlings of 188 species from 1190 seed bank and 797 seed rain samples. Seed bank, seed rain and above-ground vegetation communities differed according to habitat. Several species characteristic of managed grassland vegetation were present in the seed bank, seed rain and vegetation of the other habitats. 4. The seed banks of SNGs and the seed rain of the FAFs were generally better predicted by the surrounding above-ground vegetation than were the other habitat types. The seed rain of the grazed communities was most similar to the vegetation in the FAFs, while the seed banks of the abandoned grasslands most resembled the vegetation in SNGs. 5. Gap availability and seed input could be limiting the colonisation of target species in FAFs, while remnant populations in the seed bank and the presence of grassland specialists in the above-ground vegetation indicate that abandoned grasslands and mid-field islets could be valuable sources of future diversity in the landscape after restoration. 6. Synthesis and applications. SNG communities are able to form seed banks which survive land-use change, but their seed rain does not reflect their above-ground communities. It is important that grassland plants set seed. By connecting existing grasslands with restoration targets, increased disturbance in the target habitats would allow for colonisation via the seed bank or seed rain, while decreased grazing intensity would benefit seed production in the source grasslands. Otherwise, landscape-wide propagule availability might increase with a more varied timing and intensity of management.

No description available.

Semi-natural grasslands are one of the most threatened habitats in Scandinavia. The grassland in this study is situated in the northern part of the nature preserve of Haväng och Vitemölla strandbackar in the province of Skåne and consists of grey dunes and a pasture which partly consists of calcareous grassland and the vegetation type sand steppe which is very rare in Sweden. There are several threatened plants in the area and during the summer of 2017 their distribution was registered to be able to protect them during conservation management. The results showed that most of the area contained important species and the most important areas to protect were the sand steppe areas. This is probably due to the dry, sandy, calcareous and nutrient poor conditions in these areas which many of the threatened plants are connected to. Most of the threatened plants were found in abundance in the area but have a limited distribution in Sweden. The population of Eryngium maritimum however was very small and is threatened by extinction. The plants in the area are threatened by a long-term process of nutrient enrichment and continuous leakage of calcium which may lead to lower pH and a more nutrient rich soil which leads to a higher availability of phosphorous. This may lead to a change in species composition and loss of species richness. Continuous grazing, soil disturbance to expose lime-rich sand and also removal of litter to minimize the nutrient levels are needed to maintain favorable conditions in the area. However, the number of important species requires attention and careful planning, especially in the sand steppe areas. / Ängs-och hagmarker är några av de mest hotade och viktiga habitattyperna i Skandinavien. Gräsmarken som studerades i detta projekt ligger i norra delarna av naturreservatet Haväng och Vitemölla strandbackar i Skåne och består av gräsbevuxna sanddyner och en hage med inslag av kalkgräsmark och marktypen sandstäpp som är väldigt sällsynt i Sverige. I reservatet finns flera skyddsvärda kärlväxter och under sommaren 2017 kartlades deras utbredning för att bättre kunna skydda dem vid skötsel- och restaureringsåtgärder. Resultatet visade att större delen av området innehåller skyddsvärda arter och att de mest skyddsvärda områdena var de delar av området där det fanns inslag av sandstäpp. Detta beror med stor sannolikhet på att de flesta skyddsvärda arterna i området var knutna till de torra, sandiga, kalkhaltiga och näringsfattiga förhållanden som rådde där. De flesta skyddsvärda arter fanns i stora antal i det undersökta området men har en begränsad utbredning i Sverige. Populationen av Eryngium maritimum var dock så litet att det hotas av utrotning. I övrigt hotas växterna i området på längre sikt av ökad tillsättning av näringsämnen och långvarig urlakning av kalk. Detta kan leda till lägre pH och mer näringsrik mark och gör att den nuvarande artsammansättningen kan försvinna och ersättas. För att området ska fortsätta ha en gynnsam status kommer det krävas fortsatt bete, skapande av sandblottor för att röra upp kalkrik sand samt åtgärder så som avlägsnande av förna och ytskikt för att hålla nere näringshalten. Det stora antalet rödlistade och skyddsvärda arter i området gör dock att det krävs varsamhet och noggrann planering vid en åtgärd, framför allt i sandstäppsområdena.

The urgent issue with a changing climate has shed a light on the agricultural system and related climate mitigatory opportunities. One natural climate solution that has reached a lot of attention during the later years is carbon sequestrations in soils. The pedosphere, the outermost layer of the earth, constitute a great carbon pool and does therefore possibly provide big opportunities to adjust carbon levels in the atmosphere. Several measures can be utilized to enhance carbon levels in soils but could possibly imply additional negative impacts on other sustainability aspects. One of these are biodiversity, which are a trait strongly connected to semi-natural grasslands. This study therefore presents an overview of the knowledge regarding carbon sequestration on semi-natural grasslands, framed in a Swedish context. Conflicts and synergies between the climate aspect and other values of semi-natural grasslands are here investigated. Firstly, a lack of reliable Swedish data was identified and problems with extrapolating data from international studies regarding soil carbon sequestration were pointed out, especially in the context of semi-natural grasslands and biodiversity. The report shows that Swedish semi-natural grasslands have a low level of carbon sequestration and moreover a low opportunity to act as a climate mitigator. Biodiversity is often a more prioritized factor for these lands and often interpreted as a hinder for climate mitigatory measures. There are, however, possible opportunities to improve the climatic impact these lands have, depending on several aspects, but do often require a broad system perspective. Synergies between climate and biodiversity were difficult to identify except the questioned statement that grazers possibly could enhance soil carbon sequestration and at the same time provide biodiversity benefits. Conflicts were based on difficulties in implementation of sequestration enhancing measures since they often, locally, implied impoverished biodiversity. / Klimatförändringar är ett aktuellt problem som även satt fokus på jordbrukets roll och dess möjligheter att minska dess koldioxidutsläpp och dämpa den globala uppvärmningen. En av de möjliga naturliga klimatlösningarna är att lagra kol i jorden. Pedosfären, jordskorpans yttersta skikt, är en stor kol-pool och utgör därför potentiellt en god möjlighet till att minska koldioxidhalten i atmosfären. Det finns flertalet möjligheter att öka kolinlagringen i jorden men dessa kan dock innebära negativa konsekvenser av andra hållbarhetsaspekter. En av dessa är biologisk mångfald, som är något som naturbetesmarker är starkt kopplade till. Denna studie presenterar en översikt över kolinlagring i naturbetesmarker i en svensk kontext. Konflikter och synergier mellan kolinlagring och andra värden av naturbetesmarker tas även upp. Först kan det nämnas att det finns osäkerheter i data från svenska naturbetesmarker och att data av kolinlagring från internationella studier ofta är svåra att extrapolera till svenska marker. Det fanns även få studier som behandlade både klimatperspektivet och biologisk mångfald på naturbetesmarker. Rapporten visar även att svenska naturbetesmarker har en låg nivå av kolinlagring och därmed en låg möjlighet att agera som en mildrande faktor gällande ett förändrat klimat, där en anledning är den begränsande totala ytan som finns definierad som naturbetesmark. Däremot finns det möjligheter att förändra klimatavtrycket dessa marker genererar. I en sådan ansats bör man inkludera en rad olika faktorer och använda ett brett systemperspektiv för vidare analys. Synergier är svåra att identifiera, bortsett från en ifrågasatt åsikt om att betande djur potentiellt båda kan bidra till biologisk mångfald och öka kolinlagringen på den betande marken. Konflikter utgörs ofta av svårigheten att många potentiellt kolinlagrande åtgärder hade direkt negativa konsekvenser för den biologiska mångfalden lokalt.

No description available.