Counting for as much as 6% of Earth’s terrestrial surface, military land use constitutes an important share of human land use. Yet, only few studies analyse the general impact of military land use on landscape and biodiversity. This article presents a countrywide study of land use, land use change and biodiversity content on all Danish defence sites larger than 10 ha, comprising roughly 40,000 ha or 1% of the Danish terrestrial area. Based on interpretation of historical maps, land use history was analysed for the period from the 1870′s to the present. Furthermore, available national data were applied to assess present land use and biodiversity content within and in the surrounding of defence sites. The historical analysis revealed six typical trajectories of land use change. In terms of total area, the two most important were conservation of open, semi-natural habitat types (47%) and change from agriculture to open, semi-natural habitat types (34%). Results also show, that for sites characterised by these two land use change trajectories, present proportions of open semi-natural habitats as well as biodiversity contents are significantly higher within the sites compared to their surroundings. It is concluded that military land use in most cases had a significant beneficial impact on present day land cover composition and biodiversity.

Biodiversity loss due to changes in climate and land use has been assessed recently. The earliest biodiversity assessments already showed that species are declining faster than at any time in the past and that ecosystems are rapidly deteriorating. Moreover, these assessments indicated that the projected changes in climate and land use likely drive further biodiversity losses in the 21st century, both directly and in synergy with each other. This accumulated evidence positions climate change and land-use change among the major human-induced direct drivers of biodiversity loss. Climate change affects biodiversity as climate variables, such as temperature and precipitation, largely determine the geographical distributions of species. Hence, in areas where climate is less suitable, species shift their geographical ranges and go extinct locally. Land-use change poses immediate threats to biodiversity as the conversion of natural habitats (e.g. forests, wetlands and grasslands) into agricultural land results in populations decline and extinctions become more likely. These adverse effects consequently change ecosystems functioning and potentially affect the supply of ecosystems services and thus human well-being. Although research on climate and land-use change impacts on biodiversity and the consequent implications was repeatedly conducted, the range of estimates for these impacts remains disturbingly large. Moreover, such research relied on climate-change scenarios that depict relatively small increases in global mean temperatures (i.e. <2°C). Nowadays, the plausibility of climate-change scenarios which overshoot the 2°C policy target from The Paris Agreement, is rapidly increasing. Advances are thus needed to better understand how biodiversity will respond to such larger changes, including quantifications of the expected biodiversity decline at different climate and land-use change levels, and the effect derived from interaction mechanisms between these drivers. Furthermore, the global efforts to combat climate change and to keep global average temperature to well-below 2°C will require large mitigation commitments from the land sector with potentially both positive and negative consequences for biodiversity. These implications of land-based mitigation efforts have to be further assessed. My PhD thesis therefore aimed to explore future biodiversity trends under projected direct and synergistic changes in climate and land use and to advance understanding of climate-change mitigation consequences for biodiversity. In this thesis, climate change was indicated by global mean temperature increase (°C) and land-use change by land-use intensity levels (i.e. grazing and cropland levels) and land-cover type transitions. In Chapter 2, I assessed the magnitude of expected changes of biodiversity by systematically reviewing studies and performing a meta-analysis of the responses of species distributions to climate change. I proposed two indicators to quantify the local response of terrestrial biodiversity to climate change: the fraction of remaining species (FRS) and the fraction of remaining area (FRA) with suitable habitat for each species. The FRS and FRA calculate deviations from the original biodiversity state and both they indicate biodiversity intactness. The biodiversity response was quantified for different intervals of global mean temperature increase and for different taxonomic groups and ecosystems. The results showed that projected climate-change impacts likely cause changes to the distribution of many plants and animals and this leads to severe range contractions and local extinction of some species (i.e. decreasing biodiversity). The FRS and FRA were projected to gradually decrease with significant reductions of 14% and 35% between 1°C and 2°C increases in global mean temperature, and 32% and 54% beyond 4°C increase. This chapter showed that already at moderate temperature increases the original biodiversity significant decreased. In Chapter 3, I estimated biodiversity decline from changes in climate and land use in grassland ecosystems, which are among the most extensive ecosystems in the world. The analysis was conducted in the Central Asian grasslands, which are nowadays transforming by changes in land use and climate. I used a scenario analysis based on the latest Shared Socio-Economic Pathways (SSPs) and Representative Concentration Pathways (RCPs) (i.e. SSP-RCP scenario framework) and further detail land-use scenarios for the region. I selected contrasting socio-economic and climate conditions (i.e. SSP1-RCP4.5, SSP3-RCP8.5, SSP4-RCP4.5 and SSP5-RCP8.5). In this analysis, the climate-change impact for the selected RCP4.5 and RCP8.5 was indicated by the FRS for grasslands as estimated in Chapter 2; the land-use change impact was indicated by changes in land-use intensity derived from the land-use scenarios; and the future biodiversity was indicated by the Mean Species Abundance (MSA). The MSA expresses the mean abundance of originally occurring species in disturbed conditions (e.g. after climate change) relative to their original abundance in undisturbed habitats. The contrasting scenario combinations showed that grasslands’ biodiversity remained under continuous threat and will further decline under each scenario. The strongest impact on biodiversity was projected in SSP5-RCP8.5, where half of the grasslands will likely undergo a large decrease in their species abundance by 2100. This chapter stressed the potential vulnerability of the Central Asian grasslands to increasing land-use intensity and climate change. In Chapter 4, I explored interaction mechanisms between climate and land-use change effects on biodiversity. Climate change and land-use change are often addressed as drivers that interact synergistically in several ways and alter their mutual effects on biodiversity. I identified interaction mechanisms in which species in heavily modified landscapes may respond differently to climate change than species in pristine landscapes. These interactions arise if 1) species adapted to modified landscapes differ in their sensitivity to climate change from species adapted to natural landscapes and if 2) land-use composition restricts climate-change induced dispersal of species in fragmented landscapes. To verify these conditions, I performed systematic reviews and a meta-analysis of bioclimatic studies on species distributions in landscapes with varying proportions of cropland (first condition) and species’ dispersal under climate change in fragmented landscapes (second condition). I used the FRS as the effect-size metric in this meta-analysis. Based on the results of this analysis, I found no significant interaction effect for the first condition. This indicates that the influence of global mean temperature increase on the FRS did not change with different cropland levels. No quantitative studies were found to verify the second condition for climate-change induced dispersal of species. This chapter emphasized the need to assess interactions between land-use and climate-change effects on biodiversity, integrating other conditions, such as spatial location, adaptive capacity and time lags. In Chapter 5, I assessed carbon-dioxide-removal options in the Agriculture, Forestry and Other Land Use sectors (i.e. land-based mitigation options) implemented in different mitigation pathways that keep global temperature increase to well-below 2°C for their biodiversity impacts using the MSA indicator. Land-based mitigation options may preserve, increase or deteriorate biodiversity, because of their land-use impact. In this chapter, I reviewed climate change mitigation studies that assessed each of the selected land-based mitigation options and indicated the land transition needed to achieve a significant climate change mitigation (i.e. potential land-cover and/or land-use change). I found that reforestation of cultivated and managed areas together with restoration of wetlands deliver the largest increase of MSA, if provided the opportunity to reach mature states over time. Contrary, intensification of agricultural areas and bioenergy with carbon capture and sequestration decreased MSA locally. Options such as afforestation and reduced deforestation, either positively or negatively affect MSA. This depends on their spatial implementation and the precise forest conservation schemes. This chapter provided insights on possible synergies that emerge from certain scenarios and their benefits for current and future biodiversity conservation in regions with large land-based mitigation potential. My PhD thesis advanced scientific understanding of climate and land-use change impacts on biodiversity that can feed into the current UN Conventions on Biological Diversity and Climate Change agendas. It showed future biodiversity trends and proposed methods that translate relevant information of socio-economic and climate-change drivers to assess interactions between climate and land-use change effects on biodiversity. Such knowledge is quickly becoming an important element to develop strategies for regional and global biodiversity conservation and thus to minimize biodiversity loss. I stress the importance of holding climate change well-below 2°C as this helps to maintain the composition of local communities and their climatically suitable areas, while seeking for the desired combinations that will reduce the use of detrimental land-based mitigation options to biodiversity.

Biodiversity loss due to changes in climate and land use has been assessed recently. The earliest biodiversity assessments already showed that species are declining faster than at any time in the past and that ecosystems are rapidly deteriorating. Moreover, these assessments indicated that the projected changes in climate and land use likely drive further biodiversity losses in the 21st century, both directly and in synergy with each other. This accumulated evidence positions climate change and land-use change among the major human-induced direct drivers of biodiversity loss. Climate change affects biodiversity as climate variables, such as temperature and precipitation, largely determine the geographical distributions of species. Hence, in areas where climate is less suitable, species shift their geographical ranges and go extinct locally. Land-use change poses immediate threats to biodiversity as the conversion of natural habitats (e.g. forests, wetlands and grasslands) into agricultural land results in populations decline and extinctions become more likely. These adverse effects consequently change ecosystems functioning and potentially affect the supply of ecosystems services and thus human well-being. Although research on climate and land-use change impacts on biodiversity and the consequent implications was repeatedly conducted, the range of estimates for these impacts remains disturbingly large. Moreover, such research relied on climate-change scenarios that depict relatively small increases in global mean temperatures (i.e. <2°C). Nowadays, the plausibility of climate-change scenarios which overshoot the 2°C policy target from The Paris Agreement, is rapidly increasing. Advances are thus needed to better understand how biodiversity will respond to such larger changes, including quantifications of the expected biodiversity decline at different climate and land-use change levels, and the effect derived from interaction mechanisms between these drivers. Furthermore, the global efforts to combat climate change and to keep global average temperature to well-below 2°C will require large mitigation commitments from the land sector with potentially both positive and negative consequences for biodiversity. These implications of land-based mitigation efforts have to be further assessed. My PhD thesis therefore aimed to <em>explore future biodiversity trends under projected direct and synergistic changes in climate and land use and to advance understanding of climate-change mitigation consequences for biodiversity</em>. In this thesis, climate change was indicated by global mean temperature increase (°C) and land-use change by land-use intensity levels (i.e. grazing and cropland levels) and land-cover type transitions. In Chapter 2, I assessed the magnitude of expected changes of biodiversity by systematically reviewing studies and performing a meta-analysis of the responses of species distributions to climate change. I proposed two indicators to quantify the local response of terrestrial biodiversity to climate change: the fraction of remaining species (FRS) and the fraction of remaining area (FRA) with suitable habitat for each species. The FRS and FRA calculate deviations from the original biodiversity state and both they indicate biodiversity intactness. The biodiversity response was quantified for different intervals of global mean temperature increase and for different taxonomic groups and ecosystems. The results showed that projected climate-change impacts likely cause changes to the distribution of many plants and animals and this leads to severe range contractions and local extinction of some species (i.e. decreasing biodiversity). The FRS and FRA were projected to gradually decrease with significant reductions of 14% and 35% between 1°C and 2°C increases in global mean temperature, and 32% and 54% beyond 4°C increase. This chapter showed that already at moderate temperature increases the original biodiversity significant decreased. In Chapter 3, I estimated biodiversity decline from changes in climate and land use in grassland ecosystems, which are among the most extensive ecosystems in the world. The analysis was conducted in the Central Asian grasslands, which are nowadays transforming by changes in land use and climate. I used a scenario analysis based on the latest Shared Socio-Economic Pathways (SSPs) and Representative Concentration Pathways (RCPs) (i.e. SSP-RCP scenario framework) and further detail land-use scenarios for the region. I selected contrasting socio-economic and climate conditions (i.e. SSP1-RCP4.5, SSP3-RCP8.5, SSP4-RCP4.5 and SSP5-RCP8.5). In this analysis, the climate-change impact for the selected RCP4.5 and RCP8.5 was indicated by the FRS for grasslands as estimated in Chapter 2; the land-use change impact was indicated by changes in land-use intensity derived from the land-use scenarios; and the future biodiversity was indicated by the Mean Species Abundance (MSA). The MSA expresses the mean abundance of originally occurring species in disturbed conditions (e.g. after climate change) relative to their original abundance in undisturbed habitats. The contrasting scenario combinations showed that grasslands’ biodiversity remained under continuous threat and will further decline under each scenario. The strongest impact on biodiversity was projected in SSP5-RCP8.5, where half of the grasslands will likely undergo a large decrease in their species abundance by 2100. This chapter stressed the potential vulnerability of the Central Asian grasslands to increasing land-use intensity and climate change. In Chapter 4, I explored interaction mechanisms between climate and land-use change effects on biodiversity. Climate change and land-use change are often addressed as drivers that interact synergistically in several ways and alter their mutual effects on biodiversity. I identified interaction mechanisms in which species in heavily modified landscapes may respond differently to climate change than species in pristine landscapes. These interactions arise if 1) species adapted to modified landscapes differ in their sensitivity to climate change from species adapted to natural landscapes and if 2) land-use composition restricts climate-change induced dispersal of species in fragmented landscapes. To verify these conditions, I performed systematic reviews and a meta-analysis of bioclimatic studies on species distributions in landscapes with varying proportions of cropland (first condition) and species’ dispersal under climate change in fragmented landscapes (second condition). I used the FRS as the effect-size metric in this meta-analysis. Based on the results of this analysis, I found no significant interaction effect for the first condition. This indicates that the influence of global mean temperature increase on the FRS did not change with different cropland levels. No quantitative studies were found to verify the second condition for climate-change induced dispersal of species. This chapter emphasized the need to assess interactions between land-use and climate-change effects on biodiversity, integrating other conditions, such as spatial location, adaptive capacity and time lags. In Chapter 5, I assessed carbon-dioxide-removal options in the Agriculture, Forestry and Other Land Use sectors (i.e. land-based mitigation options) implemented in different mitigation pathways that keep global temperature increase to well-below 2°C for their biodiversity impacts using the MSA indicator. Land-based mitigation options may preserve, increase or deteriorate biodiversity, because of their land-use impact. In this chapter, I reviewed climate change mitigation studies that assessed each of the selected land-based mitigation options and indicated the land transition needed to achieve a significant climate change mitigation (i.e. potential land-cover and/or land-use change). I found that reforestation of cultivated and managed areas together with restoration of wetlands deliver the largest increase of MSA, if provided the opportunity to reach mature states over time. Contrary, intensification of agricultural areas and bioenergy with carbon capture and sequestration decreased MSA locally. Options such as afforestation and reduced deforestation, either positively or negatively affect MSA. This depends on their spatial implementation and the precise forest conservation schemes. This chapter provided insights on possible synergies that emerge from certain scenarios and their benefits for current and future biodiversity conservation in regions with large land-based mitigation potential. My PhD thesis advanced scientific understanding of climate and land-use change impacts on biodiversity that can feed into the current UN Conventions on Biological Diversity and Climate Change agendas. It showed future biodiversity trends and proposed methods that translate relevant information of socio-economic and climate-change drivers to assess interactions between climate and land-use change effects on biodiversity. Such knowledge is quickly becoming an important element to develop strategies for regional and global biodiversity conservation and thus to minimize biodiversity loss. I stress the importance of holding climate change well-below 2°C as this helps to maintain the composition of local communities and their climatically suitable areas, while seeking for the desired combinations that will reduce the use of detrimental land-based mitigation options to biodiversity.

Biodiversity conservation is often considered to be an important co-benefit of REDD+ and other mechanisms aiming to increase carbon in biomass and soil to mitigate climate change. This reasoning is based on the assumption that the level of biodiversity and ecosystem carbon are positively correlated. Firstly, however, studies have shown both positive and negative relationships. Secondly, incentives for additional ecosystem carbon do not trigger random or all potential changes in land-use, but often concentrate on one or a few specific changes that could have an opposite effect than the general trend indicates. Therefore, it is important to study biodiversity impacts of plausible measures to increase carbon. We obtained land-use scenarios on pathways to increase carbon based on 97 face-to-face interviews of local land-use experts in twelve landscapes in seven countries and five continents. We then conducted another set of face-to-face interviews with biodiversity experts yielding 2963 estimations concerning the value of land-use classes for 264 taxa of fauna and flora in these landscapes. We found positive carbon to biodiversity relationships in ten of the twelve landscapes. The biodiversity impacts of measures to increase carbon were positive in eleven of the twelve landscapes. Our results indicate that a random land-use change that increases biodiversity is also likely to increase carbon and vice versa.

Biodiversity hotspots are conservation priority areas that meet two criteria: they must have lost ≥70% of their primary vegetation, and they must contain ≥1500 endemic vascular plant species. Given the limited time and resources available for conservation and predicted future land-use change, it is necessary for conservation efforts in biodiversity hotspots to become more effective. In this study, we identified regions that have lost ≥70% of their primary vegetation and in which the past endemic vascular plant species richness was estimated to be higher than the biodiversity hotspot threshold of 1500 species (i.e., regions that were possible biodiversity hotspots). Next, we compared historical land-use change data from 1500 to 2010 between the identified regions and biodiversity hotspots. We found that the rate of land-use change in the biodiversity hotspots was significantly lower than that in the identified regions, suggesting that rapid land-use change poses an increased threat to endemic plants and is associated with the loss of endemic plant diversity. Biodiversity hotspots thus likely maintain many species that are vulnerable to rapid land-use change. Fortunately, some identified regions have not experienced rapid land-use change and thus have the potential to be newly recognized as biodiversity hotspots: the Altai-Sayan Montane Forests, the Amur-Heilong River Basin, and the Southeast China Subtropical Forests. Our findings reinforce the importance of prioritizing biodiversity hotspots for conservation and emphasize the need to develop efficient conservation strategies specialized to mitigate the effects of rapid land-use change on biodiversity.

Population-decline and subsequent underuse of social-ecological landscapes are increasingly being recognized as one of the crucial drivers behind the loss and deterioration of biodiversity and ecosystem services. In line with this, the study aimed to explore how alternative development pathways influence future land-use patterns, biodiversity and ecosystem services against a rapidly declining population in the Noto peninsula of Japan. By combining land-use simulation and evaluation of ecosystem services, the study formulated four exploratory scenarios for 2050, assuming a contrasting level of the society’s reliance on domestic natural capital and different demographic patterns. At first, we analyzeds historical land-use changes between 1997 and 2007 and thereby simulated four plausible alternative scenarios using the Multi-Layer Perceptron Neural Network model. These scenarios were further used to quantify ecosystem services and landscape heterogeneity (as biodiversity indicator). The scenario analysis demonstrated that future land-use pattern could vary drastically depending on how the society utilize local natural capital even under the severe depopulation trend, whereas demographic patterns, in general, did not make discernible differences in land-use, biodiversity and ecosystem services. Nevertheless, a land-use change made considerable differences in the level of ecosystem services and landscape heterogeneity with varying degrees. Our analysis suggested that ecosystem services such as food production and nitrogen retention as well as landscape heterogeneity would decrease considerably by 2050 under the scenarios where the utilization of local natural capital decline and a significant amount of farmland are abandoned. Our findings highlight the vital role of land-use and agricultural policy in shaping the future availability of ecosystem services and biodiversity in this area.

Changes in land use and land cover (LULC) have major effects on biodiversity and ecosystem services. Land change models can simulate future trends of ecosystem services under different scenarios to inform the actions of decision makers towards building a more sustainable society. LULC data are essential inputs for predicting future land changes. It is now possible to derive high-resolution LULC maps from satellite data using remote sensing techniques. However, the classification of land categories in these maps is too limited to sufficiently assess biodiversity and ecosystem services. This study aims to develop land-use scenarios, using an appropriate LULC map, to enable assessment of biodiversity and ecosystem services at the national scale. First, we developed an LULC dataset using vegetation inventories based on field records of vegetation collected throughout the country in the periods 1978–1987, 1988–1998 and 1999–2014. The vegetation maps consist of over 905 vegetation categories, from which we aggregated the most prevalent categories into 9 LULC categories. Second, we created a business-as-usual scenario and plausible future scenarios on the land use change maps using the Land Change Model tool. In the process of developing the model, we considered key drivers including biophysical and socio-economic factors. The results showed some key land changes as consequences of intensive/extensive land-use interventions. These derived scenario maps can be used to assess the impacts of future land change on biodiversity and ecosystem services.

Diets lower in meat could reduce agricultural expansion and intensification thereby reducing biodiversity impacts. However, land use requirements, associated with alternate diets, in biodiverse regions across different taxa are not fully understood. We use a spatially explicit global food and land system model to address this gap. We quantify land-use change in locations important for biodiversity across taxa and find diets low in animal products reduce agricultural expansion and intensity in regions with high biodiversity. Reducing ruminant meat consumption alone however was not sufficient to reduce fertiliser and irrigation application in biodiverse locations. The results differed according to taxa, emphasising that land-use change effects on biodiversity will be taxon specific. The links shown between global meat consumption and agricultural expansion and intensification in the biodiverse regions of the world indicates the potential to help safeguard biodiverse natural ecosystems through dietary change.

PURPOSE: The biosphere is progressively subjected to a variety of pressures resulting from anthropogenic activities. Habitat conversion, resulting from anthropogenic land use, is considered the dominant factor driving terrestrial biodiversity loss. Hence, adequate modelling of land use impacts on biodiversity in decision-support tools, like life cycle assessment (LCA), is a priority. State-of-the-art life cycle impact assessment (LCIA) characterisation models for land use impacts on biodiversity translate natural habitat transformation and occupation into biodiversity impacts. However, the currently available models predominantly focus on total habitat loss and ignore the spatial configuration of the landscape. That is, habitat fragmentation effects are ignored in current LCIAs with the exception of one recently developed method. METHODS: Here, we review how habitat fragmentation may affect biodiversity. In addition, we investigate how land use impacts on biodiversity are currently modelled in LCIA and how missing fragmentation impacts can influence the LCIA model results. Finally, we discuss fragmentation literature to evaluate possible methods to include habitat fragmentation into advanced characterisation models. RESULTS AND DISCUSSION: We found support in available ecological literature for the notion that habitat fragmentation is a relevant factor when assessing biodiversity loss. Moreover, there are models that capture fragmentation effects on biodiversity that have the potential to be incorporated into current LCIA characterisation models. CONCLUSIONS AND RECOMMENDATIONS: To enhance the credibility of LCA biodiversity assessments, we suggest that available fragmentation models are adapted, expanded and subsequently incorporated into advanced LCIA characterisation models and promote further efforts to capture the remaining fragmentation effects in LCIA characterisation models.