| 1. |
- Lindgren, Jessica, 1971-
(författare)
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Small remnant habitats : Important structures in fragmented landscapes
- 2017
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The world-wide intensification of agriculture has led to a decline in species richness due to land use change, isolation, and fragmentation of natural and semi-natural habitats in agricultural and forestry landscapes. As a consequence, there is a current landscape management focus on the importance of green infrastructure to mitigate biodiversity decline and preserve ecosystem functions e.g. pollination services and pest control. Even though intensification in agriculture has been ongoing for several hundreds of years, remnant habitats from earlier management practices may still be remaining with a surprisingly high plant richness. Preserving these habitats could help conserving plant species richness in agricultural landscapes, as well as other organisms that are dependent on plants for food and shelter.In this thesis I focus on two small remnant habitats; midfield islets and borders between managed forest and crop field in southeastern Sweden. In the past, both habitats were included in the grazing system and therefore often still have remnant population of grassland specialist species left today. I have used these two remnant habitats as model habitats to investigate the effect of landscape factors and local factors on species richness of plants, flower morphologies and plants with fleshy fruits. Additively, I analysed the effect of surrounding landscape and local openness on the functions; pollination success, biological pest control of aphids and seed predation on midfield islets.One of my studies showed that spatial distribution and size of the habitat affected plant species richness. Larger habitat size and higher connectivity between habitats increased species richness of plants in the habitats. Openness of the habitats was shown to be an important factor to increase species richness and richness of flower morphologies, both on midfield islets and in forest borders. Even though midfield islets had the highest species and morphology richness, both habitat types are needed for habitat complementary as forest borders have more plants with fleshy fruits and a higher richness of plant species that flowers in spring/early summer. It was also shown that a more complex forest border, not just with gaps in the canopy, but also with high variation in tree stem sizes increases plant species richness in the field layer. The conclusion is that by managing small remnant habitats to remain or become more semi-open and complex in their structure, would increase species richness of plants, grassland specialist species, and flower morphologies. It would also increase some ecosystem functions as seed predation and biologic pest control of aphids are more effective close to trees. If both midfield islets and forest borders would be managed to be semi-open, the area and connectivity of semi-open habitat would increase in the agricultural landscape, which may also improve pollination success as the connectivity between populations has a possibility to increase. Grassland specialist species are clearly abundant in the small remnant habitats. As the decline of semi-natural grasslands is causing a decline in grassland specialists’ species, not only plants, I recommend that small remnant habitats are included in conservation and management plans and strategies to improve habitat availability and connectivity for grassland species in agricultural landscapes.
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| 2. |
- Queiroz, Cibele, 1981-
(författare)
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Managing for biodiversity and ecosystem services in a context of farmland abandonment
- 2013
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- In agricultural landscapes around the world, intensification of production and land abandonment are the two main trends impacting biodiversity and ecosystem services. Intensified agriculture is mostly seen as negative for biodiversity but effects of abandonment are controversial among scientists and practitioners. While abandonment can be detrimental to biodiversity in non-intensive farming systems, it can also provide an opportunity for regeneration of natural habitats. This thesis examines effects of different management options on biodiversity along an abandonment gradient from farmland to forest. It combines insights from a local case study in NW Portugal with an inter-regional meta-analysis on the effects of land-use change on response diversity, and a global meta-analysis on how impacts of abandonment on biodiversity are reported in scientific studies. Effects of abandonment were assessed for species richness and functional diversity for multiple taxa, and for the provision of multiple ecosystem services.At the global scale, abandonment impacts on biodiversity were reported in contrasting ways across world regions, and this was influenced by conservation views focused on pre vs. post abandonment conditions. In the study area, intermediate farming intensity, compared to abandoned forest habitats, generated higher plant richness at small scales and when post-abandonment forest was highly fragmented. In contrast, at larger scales, both farmland and forest had high species and functional diversity of plants and birds, while moths were more diverse in forests. All land uses provided multiple ecosystem services, but while provisioning services were highest in farmland, forests benefited regulating services, a difference not reflected in species richness distribution. In contrast to current European policies, abandonment was not found to be disadvantageous to biodiversity, except for species richness at very small scales. Thus, both farming and post-abandonment succession can generate high value ecosystems. In order to sustainably manage abandoned lands, farmland abandonment needs to be analyzed in a broader perspective, combining different types of indicators, from species to ecosystem services, and avoiding pre-conceived ideas on conservation, not always beneficial to the sustainable management of these landscapes.
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| 3. |
- Alavaisha, Edmond, 1988-
(författare)
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Agricultural expansion impacts on wetland ecosystem services from Kilombero Valley, Tanzania
- 2020
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Land use change has major impact on the world’s wetland ecosystems and biodiversity. The motivation behind this change has been to increase agricultural production, often resulting in negative effects on water quality and soil fertility. Tanzania has carried out a large expansion and intensification of agriculture under the Kilimo kwanza (First agriculture) initiative which has triggered the need for better knowledge on land use change effects and associated ecosystem functioning. This thesis considers small-scale irrigation schemes to understand the effects of agriculture expansion and farming practices on nutrients, water quality and ecosystem services (ES) in Kilombero Valley, Tanzania. The study approach is multidisciplinary involving interviews, remote sensing, geographical information system techniques, and in-field soil and water ecological sampling. The major land use change in the valley during the last three decades was transformation from forest, bushland and grassland into cultivated land. The rate of change was faster adjacent to irrigation schemes and most changes occurred downstream irrigation canals, close to the floodplain. Irrigation and fertilization contributed to soil carbon and nitrogen accumulation in crop fields, which both declined in concentration with depth into the soil. However, such management practices and agricultural land expansion had impacts on several ES – especially water quality in streams. Streams surrounded mainly by cultivated land, as well as downstream areas, had lower water quality compared to streams with less settlement, more natural vegetation and upstream areas. Furthermore, when evaluated, macroinvertebrates indices were found to be a good indicator of water quality and a complement to chemical and physical water analysis. Irrigation farming produced more food compared to rainfed farming, and also other ES such as flood regulation, erosion control and several cultural services, depending on the river discharge. The thesis shows the importance to use irrigation/fertilization management to enhance soil fertility and preserve soil structure, but also the need for proper irrigation management to prevent flooding and erosion, conserve natural vegetation, and protect water quality. To enhance nature conservation, preserve biodiversity and secure future supply of ES in the valley, investment in irrigation infrastructures should be done at small-scale to mitigate the large-scale exploitation of Kilombero wetland.
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| 4. |
- Jakobsson, Simon, 1987-
(författare)
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Wooded or treeless pastures? : Linking policy, farmers' decisions and biodiversity
- 2018
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Worldwide, biodiversity conservation is one of the key challenges for a sustainable future of nature and society. It is particularly important to preserve high quality habitats within otherwise intensively managed agricultural landscapes. Within the European Union (EU), farmers are highly dependent on agricultural subsidies through the Common Agricultural Policy (CAP), which hence have a strong influence on management and biodiversity. In European agricultural landscapes, wooded pastures form important habitats that contribute to landscape level heterogeneity and high local biodiversity, values which are often closely linked to trees. Unfortunately, many of these values were put at risk when a tree density limitation was introduced within the CAP, encouraging farmers to keep pastures open and ensuring grazing management. However, limiting tree density to a specific number to increase biodiversity finds little basis in the scientific literature. The main objective of this thesis is therefore to investigate how different measures of biodiversity across multiple taxa are affected by tree density and to study the farmers' perspective on this CAP regulation. Wooded pastures in the biosphere reserve Östra Vätterbranterna in southern Sweden were used as study sites. This thesis shows that encouraging farmers to cut trees to receive subsidies weakens the link between social and ecological values of wooded pastures, with potential subsequent losses in biodiversity. Trees were almost exclusively positive for biodiversity within this study system, increasing the species richness of plants, birds and bats. However, functional diversity across these taxa were mainly affected by other vegetation attributes within and around the pastures, such as shrub density and surrounding forest cover. A seed sowing experiment showed how trees partly shape plant communities already at the germination stage. Further, responses of functional diversity was mainly driven by resource use related traits among plants and birds, whereas bat functional diversity responses were mainly determined by their ability to manoeuvre through the micro-habitats of wooded pastures. Based on this thesis, I conclude that the tree density limit proposed by the EU has failed to capture the unique biological values of continuously managed wooded pastures and that the social-ecological links between policy, management and biodiversity are threatened by number specific governance of nature. It is therefore promising that the EU in November 2017 announced to open up for excluding the tree density focus in the CAP. Further development of the CAP can benefit from the findings of this thesis, revealing important knowledge gaps on biodiversity patterns in relation to trees in pastures.
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| 5. |
- Malinga, Rebecka, 1976-
(författare)
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Ecosystem services in agricultural landscapes : A study on farming and farmers in South Africa and Sweden
- 2016
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Humanity is facing challenges of sustainably producing enough food for a growing population without further eroding the world’s ecosystems. Transformation of natural habitats into agriculture has resulted in opportunities for civilization, but has also led to land degradation and loss of biodiversity, threatening the generation of ecosystem services. A better understanding of interlinkages and trade-offs among ecosystem services, and the spatial scales at which services are generated, used and interact, is needed in order to successfully inform land use policies. This includes the need to develop transdisciplinary tools that can disentangle the relationships between the supply of and demand for ecosystem services. This thesis investigates agricultural landscapes as complex social-ecological systems, and uses a multi-method approach to assess ecosystem service generation from different types of agricultural landscapes and to examine the social-ecological nature of these services. More specifically, the thesis discusses the importance of appropriate spatial scales, explores landscape change, integrates stakeholder knowledge and develops tools to investigate supply and demand of multiple ecosystem services. Paper I reviews the literature on ecosystem service mapping, revealing that services were mostly mapped at intermediate spatial scales (municipality and province), and rarely at local scales (farm/village). Although most of the reviewed studies used a resolution of 1 hectare or less, more case-specific local scale mapping is required to unravel the fine-scale dynamics of ecosystem service generation that are needed to inform landscape planning. To explore future uncertainties and identify relevant ecosystem services in a study area, paper II builds alternative scenarios using participatory scenario planning in the Upper Thukela region, South Africa. The paper compares methods to select services for an ecosystem service assessment showing that scenario planning added limited value for identifying ecosystem services, although it improved knowledge of the study area and availed useful discussions with stakeholders. Papers III and IV combines social and biophysical data to study the supply and demand of ecosystem services at farm- and landscape level, through participatory mapping and expert assessments in the Upper Thukela region, South Africa (paper III), and through in-depth interviews and biophysical surveys in Uppsala County, Sweden (paper IV), including small-scale and large-scale farmers. Both papers find apparent differences between the farmer groups in terms of the supply and the demand of services, and also the capacity of the farmers to influence the generation of services (paper III). Paper IV further establishes the importance of using multiple indicators combining social and biophysical data to quantify and investigate the complex social-ecological nature of ecosystem services. A cross-case comparison of ecosystem service bundles, using data from papers III and IV, finds similarities in bundles generated in the large-scale systems, while the small-scale agriculture bundles varied. This thesis provides new insights into the social-ecological generation of ecosystem services at fine scales such as farm and landscape levels, and shows the importance of including the knowledge of various stakeholders, combining different methods and tools to increase the understanding of supply and demand of ecosystem services.
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| 6. |
- Borgström, Sara, 1977-
(författare)
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Urban shades of green : Current patterns and future prospects of nature conservation in urban landscapes
- 2011
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Urban nature provides local ecosystem services such as absorption of air pollutants, reduction of noise, and provision of places for recreation, and is therefore crucial to urban sustainable development. Nature conservation in cities is also part of the global effort to halt biodiversity decline. Urban landscapes, however, display distinguishing social and ecological characteristics and therefore the implementation of nature conservation frameworks into cities, requires reconsideration of what nature to preserve, for whom and where. The aim of this thesis was to examine the current urban nature conservation with special focus on formally protected areas, and discuss their future role in the urban landscape. A social-ecological systems approach was used as framework and both quantitative and qualitative methods were applied. The studies were performed at local to regional scales in the southern part of Sweden. Four key questions were addressed: i) What are the characteristics of nature conservation in urban landscapes? ii) How does establishment of nature conservation areas affect the surrounding urban landscape? iii) In what ways are spatial and temporal scales recognized in practical management of nature conservation areas? and iv) How can the dichotomy of built up and nature conservation areas be overcome in urban planning? Nature reserves in urban, compared to rural landscapes were in general fewer, but larger and included a higher diversity of land covers. They were also based on a higher number and different kinds of objectives than rural nature reserves. Urbanisation adjacent to nature reserves followed the general urbanisation patterns in the cities and no additional increase in urban settlements could be detected. In general, there was a lack of social and ecological linkages between the nature conservation areas and the urban landscape and practical management showed a limited recognition of cross-scale interactions and meso-scales. Such conceptual and physical isolation risks decreasing the public support for nature conservation, cause biodiversity decline, and hence impact the generation of ecosystem services. A major future challenge is therefore to transform current conservation strategies to become a tool where urban nature is perceived, planned and managed as valuable and integrated parts of the city. To enable social-ecological synergies, future urban planning should address proactive approaches together with key components like active enhancement of multifunctional landscapes, cross-scale strategies and border zone management.
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| 7. |
- Jakobsson, Simon, 1987-
(författare)
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Woody or treeless pastures? Effects of EU tree density limitations on biodiversity in woody pastures
- 2015
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The high biological and cultural values of traditionally managed rural landscapes are threatened by habitat change and degradation due to homogenisation through modern agricultural practices and abandonment. Woody pastures are important for many different taxa, and hence crucial for biodiversity conservation in these agricultural landscapes. To mitigate biodiversity loss, agricultural policy recommendations and subsidies are important tools, but if not implemented properly they may have the opposite effect. To keep agricultural landscapes open and to preserve biodiversity, the Common Agricultural Policy (CAP) of the European Union (EU) regulates how many trees farmers are allowed to have on their pastures to receive subsidies from the EU. A seemingly arbitrary limit was set to 50 trees/ha in 2003, which changed recently to 100 trees/ha. However, woody pastures are environments where high nature values often arise from the trees themselves, whereas there is little evidence on how biodiversity is directly affected by tree density in woody pastures. In this study, the tree density limit is targeted to investigate the effects on plant and bird diversity in 64 Swedish woody pastures along a gradient from 0 to 200 trees/ha. The results show that tree density is one of the major drivers of plant diversity, by favouring shade tolerant species without having a negative effect on less shade tolerant grassland specialists. Tree density positively affect bird diversity, an effect saturating at medium dense pastures but large species turnover rates along the gradient point at a variety of species found within woody pastures. Woody pastures with high tree densities in this study contribute substantially to biodiversity as heterogeneous environment enables high species richness. This thesis demonstrates a mismatch between subsidy systems and biological values that need to be further scrutinised to preserve biodiversity of agricultural landscapes.
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| 8. |
- Staveley, Thomas, 1982-
(författare)
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Fish in the coastal seascape : exploring ecological processes and connectivity for conservation of temperate fish communities
- 2019
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The need to understand patterns and processes in the marine environment has never been so profound as today, particularly as anthropogenic pressures upon coastal regions are drastically affecting habitats and species across a vast range. One approach to further understand these patterns and processes is through the use of seascape ecology methods. Pertinently, fish are ideal candidates to use in many seascape ecological studies due to their mobility and potential to connect a multitude of patches and habitats throughout their life cycle. They also serve as fundamental components in coastal food webs and are of economic benefit. This thesis strives to answer how fish assemblages are affected by ecological and environmental patterns and changes in temperate seascapes throughout the Swedish Skagerrak and the Baltic Sea. Initially, the spatial arrangement of benthic habitat patches in coastal Skagerrak was investigated in relation to the fish community inhabiting seagrass meadows. Seascape structure and complexity was shown to create optimal or sub-optimal areas for certain parts of the fish community. For instance, simpler seascapes (e.g. less habitat patches and edges) were found to have a higher density of juvenile fish, while wrasse densities were related to more complex seascapes. This offers insights into the consequences of spatial patterning in the marine environment and possible effects of habitat loss in the ecosystem (paper I). Through surveying fish assemblages in common, shallow-water habitats, the more structurally complex habitats, i.e. seagrass and macroalgae, were found to harbour a greater fish abundance compared to the less complex unvegetated soft bottoms. However, all three habitats were deemed important for their role in supporting juvenile fish species, thus suggesting that embayments in this environment might function as seascape nurseries (paper II). The importance of connectivity of a marine predator was discovered using acoustic telemetry and network analysis. This study demonstrated that sea surface temperature was of major importance for Atlantic cod movement dynamics within a fjord system as well as revealing the significance of localised connectivity at varying spatial and temporal scales (paper III). Finally, spatial pattern relationships and fish assemblages were explored in Baltic seagrass meadows. Fish assemblages were dominated by meso-predators (i.e. three-spined stickleback) both during summer and autumn, with a noticeable lack of larger piscivorous species throughout both seasons. Correlative analysis showed that fish densities were influenced by seagrass habitat structure (negatively), area of bare sediment (negatively) and habitat patch diversity (positively) (paper IV). This thesis has lifted a central role in addressing important seascape ecology questions and tools in the temperate marine environment. Specifically, it highlights the importance of analysing patterns and processes at multiple scales to gain a more comprehensive understanding of the relationships between fish and their environments, which is relevant for marine spatial planning and conservation.
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| 9. |
- Waldén, Emelie, 1984-
(författare)
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Restoration of semi-natural grasslands : Impacts on biodiversity, ecosystem services and stakeholder perceptions
- 2018
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Humans play a major role shaping the living conditions for not only ourselves, but also all other species on Earth. In fact, some species-rich habitat types require human management to uphold the biodiversity and related ecosystem services. One of the world’s most biodiverse habitats on small spatial scales, semi-natural grasslands, have been formed over the course of centuries through extensive grazing and mowing. However, due to political and economic reasons, up to 90% of the European semi-natural grasslands have been lost during the 20th century. To counteract these drastic losses, restoration actions are implemented in environmental policies across Europe. Yet, knowledge of the long-term restoration effects on biodiversity and ecosystem services is still limited. The vast need for future restoration also requires a better understanding of how different pre-conditions affect the restoration outcome, as well as how stakeholders perceive restoration, to be able to prioritise between sites and recognise the limitations of the restoration process. In this thesis, I examine restoration outcomes in Swedish semi-natural grasslands, in terms of plant diversity, associated ecosystem services and from the farmers’ and land-owners’ perspective. The outcome is also analysed in relation to environmental factors at the local and landscape scale. I found that the overall community composition recovered to resemble intact reference communities, but it took relatively long time (12-20 years). Moreover, the reference sites still had higher species richness both at large and small spatial scales, more grassland specialist species and a higher abundance of plant species important to the five tested ecosystem services (meat production, pollination, water retention, temperature regulation and cultural heritage). My results show that prioritising large, unfertilised, newly abandoned grasslands situated in landscapes containing a large grassland specialist species pool and high amounts of intact and remnant semi-natural grasslands, could speed up the plant recovery. However, prioritising fast results does not necessarily ensure long-term success at a larger spatial scale. Since restoration success can be interpreted differently depending on evaluation measure used, pre-defined, clear and realistic goals are essential. While the surveyed farmers and landowners overall perceived the restoration as successful, 40% were unsure whether the grasslands will be managed in the future. Low profitability still poses a threat to their maintenance and thus, also to the coupled biodiversity and ecosystem services. Policy changes are therefore urgently needed to facilitate incentives for sustained management of restored and intact European semi-natural grasslands in a long-term perspective.
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| 10. |
- Lindborg, Regina, 1966-
(författare)
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Land Use Change in Space and Time : implications for plant species conservation in semi-natural grasslands
- 2004
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Land use change has during the last century altered the traditional rural landscape in Sweden, resulting in a major decline in species diversity. Traditional small-scale farming, with a remarkably high small-scale species richness, has changed in favour of rationalized agriculture, and many semi-natural grasslands, i.e. traditionally managed pastures and meadows, have become abandoned. In this thesis I examine how spatio-temporal processes affect plant species in Swedish semi-natural grasslands exposed to habitat degradation as well as recovery (restoration). I also discuss how to conserve plant species associated with semi-natural grasslands. In general, species responded slowly to habitat degradation, but quickly to improvement of habitat quality. Population viability analysis (PVA) of the grazing favoured herb Primula farinosa suggested, in contrast to historical records, that populations in abandoned grasslands performed better than populations in traditionally managed grasslands, a result questioning the accuracy of PVAs. Restoration of grasslands counteracted species richness decline and the number of species increased within seven years after restoration. It was possible to recruit grassland species in grazed former arable fields by artificial seed-sowing. This may help to speed up the natural recruitment, which often is low due to dispersal limitations in modern fragmented landscapes. Studies at larger regional scales showed century long time-lags in the response of plant species richness to land use change. Species richness was not related to present-day connectivity of grasslands, but positive effects appeared for grassland configuration in 1950s and 1900s. Thus, making conservation guidelines based solely on present-day data may be strongly misleading and under-estimate the actual risk of species loss. To secure long-term survival of species, it is important to focus on processes associated with larger spatial scales. This may benefit natural dynamics at longer time-scales, where abandoned and restored grasslands, together with species-rich semi-natural grasslands, could become natural parts of sustainable landscape management.
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