| 1. |
- Aalto, Juha, et al.
(författare)
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Revealing topoclimatic heterogeneity using meteorological station data
- 2017
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Ingår i: International Journal of Climatology. - : Wiley. - 0899-8418 .- 1097-0088. ; 37:Suppl. 1, s. 544-556
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Tidskriftsartikel (refereegranskat)abstract
- Climate is a crucial driver of the distributions and activity of multiple biotic and abiotic processes, and thus high-quality and high-resolution climate data are often prerequisite in various environmental research. However, contemporary gridded climate products suffer critical problems mainly related to sub-optimal pixel size and lack of local topography-driven temperature heterogeneity. Here, by integrating meteorological station data, high-quality terrain information and multivariate modelling, we aim to explicitly demonstrate this deficiency. Monthly average temperatures (1981-2010) from Finland, Sweden and Norway were modelled using generalized additive modelling under (1) a conventional (i.e. considering geographical location, elevation and water cover) and (2) a topoclimatic framework (i.e. also accounting for solar radiation and cold-air pooling). The performance of the topoclimatic model was significantly higher than the conventional approach for most months, with bootstrapped mean R-2 for the topoclimatic model varying from 0.88 (January) to 0.95 (October). The estimated effect of solar radiation was evident during summer, while cold air pooling was identified to improve local temperature estimates in winter. The topoclimatic modelling exposed a substantial temperature heterogeneity within coarser landscape units (>5 degrees C/1 km(-2) in summer) thus unveiling a wide range of potential microclimatic conditions neglected by the conventional approach. Moreover, the topoclimatic model predictions revealed a pronounced asymmetry in average temperature conditions, causing isotherms during summer to differ several hundreds of metres in altitude between the equator and pole facing slopes. In contrast, cold-air pooling in sheltered landscapes lowered the winter temperatures ca. 1.1 degrees C/100m towards the local minimum altitude. Noteworthy, the analysis implies that conventional models produce biassed predictions of long-term average temperature conditions, with errors likely to be high at sites associated with complex topography.
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| 2. |
- Ango, Tola Gemechu, et al.
(författare)
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Balancing Ecosystem Services and Disservices : Smallholder Farmers' Use and Management of Forest and Trees in an Agricultural Landscape in Southwestern Ethiopia
- 2014
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Ingår i: Ecology and Society. - 1708-3087. ; 19:1
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Tidskriftsartikel (refereegranskat)abstract
- Farmers' practices in the management of agricultural landscapes influence biodiversity with implications for livelihoods, ecosystem service provision, and biodiversity conservation. In this study, we examined how smallholding farmers in an agriculture-forest mosaic landscape in southwestern Ethiopia manage trees and forests with regard to a few selected ecosystem services and disservices that they highlighted as beneficial or problematic. Qualitative and quantitative data were collected from six villages, located both near and far from forest, using participatory field mapping and semistructured interviews, tree species inventory, focus group discussions, and observation. The study showed that farmers' management practices, i.e., the planting of trees on field boundaries amid their removal from inside arable fields, preservation of trees in semimanaged forest coffee, maintenance of patches of shade coffee fields in the agricultural landscape, and establishment of woodlots with exotic trees result in a restructuring of the forest-agriculture mosaic. In addition, the strategies farmers employed to mitigate crop damage by wild mammals such as baboons and bush pigs, e. g., migration and allocation of migrants on lands along forests, have contributed to a reduction in forest and tree cover in the agricultural landscape. Because farmers' management practices were overall geared toward mitigating the negative impact of disservices and to augment positive services, we conclude that it is important to operationalize ecosystem processes as both services and disservices in studies related to agricultural landscapes.
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| 3. |
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| 4. |
- Ango, Tola Gemechu, et al.
(författare)
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Processes of Forest Cover Change since 1958 in the Coffee-Producing Areas of Southwest Ethiopia
- 2020
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Ingår i: Land. - : MDPI AG. - 2073-445X. ; 9:8
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Tidskriftsartikel (refereegranskat)abstract
- We investigated the spatial relations of ecological and social processes to point at how state policies, population density, migration dynamics, topography, and socio-economic values of ‘forest coffee’ together shaped forest cover changes since 1958 in southwest Ethiopia. We used data from aerial photos, Landsat images, digital elevation models, participatory field mapping, interviews, and population censuses. We analyzed population, land cover, and topographic roughness (slope) data at the ‘sub-district’ level, based on a classification of the 30 lowest administrative units of one district into the coffee forest area (n = 17), and highland forest area (n = 13). For state forest sites (n = 6) of the district, we evaluated land cover and slope data. Forest cover declined by 25% between 1973 and 2010, but the changes varied spatially and temporally. Losses of forest cover were significantly higher in highland areas (74%) as compared to coffee areas (14%) and state forest sites (2%), and lower in areas with steeper slopes both in coffee and highland areas. Both in coffee and highland areas, forest cover also declined during 1958–1973. People moved to and converted forests in relatively low population density areas. Altitudinal migration from coffee areas to highland areas contributed to deforestation displacement due to forest maintenance for shade coffee production in coffee areas and forest conversions for annual crop production in highland areas. The most rapid loss of forest cover occurred during 1973–1985, followed by 2001–2010, which overlapped with the implementations of major land and forest policies that created conditions for more deforestation. Our findings highlight how crop ecology and migration have shaped spatial variations of forest cover change across different altitudinal zones whilst development, land, and forest policies and programs have driven the temporal variations of deforestation. Understanding the mechanisms of deforestation and forest maintenance simultaneously and their linkages is necessary for better biodiversity conservation and forest landscape management.
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| 5. |
- Arnqvist, Goran, et al.
(författare)
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Falsk marknadsföring om hållbart skogsbruk
- 2022
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Ingår i: Svenska Dagbladet Debatt. - 1101-2412.
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Tidskriftsartikel (populärvet., debatt m.m.)abstract
- Dagens svenska skogsbruk är inte ekologiskt hållbart. Att saluföra det som hållbart är därför – för att tala klarspråk – falsk marknadsföring, skriver forskare.
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| 6. |
- Ayalew Nurihun, Biruk, 1983-
(författare)
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The relationship between climate, disease and coffee yield: optimizing management for smallholder farmers
- 2023
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Climate change and diseases are threatening global crop production. Agroforestry systems, which are characterized by complex multispecies interactions, are considered to provide nature-based solutions for climate change mitigation and pest and disease regulation. Understanding the role of the abiotic environment and species interactions in shaping diseases and yield in agroforestry systems would enable us to develop effective ecologically-informed pest and disease management under a changing climate, support sustainable agricultural practices, and maximize the benefits gained from agroforestry systems. To gain such a comprehensive understanding of what shapes pest and disease levels and yield in agroforestry systems, we need to investigate how the interactions between agroforestry system components, such as trees, crops and their associated organisms, vary in space and time, and how they are influenced by abiotic factors in terms of pests and diseases and yield. In this thesis, my overarching goal was to understand how microclimate and management impact major coffee pests and diseases, their natural enemies, and coffee yield, as well as farmers’ perceptions of climate change and climate-mediated changes in disease dynamics and yield, with the aim of using these insights to optimize management decisions for smallholder farmers in southwestern Ethiopia. With this aim, I selected 58 sites along a gradient of management intensity, ranging from minimal management in the natural forest to moderate management in smallholder farms and intensive management in commercial plantations. As an approach, I combined observational and interview studies to examine i) the impact of shade tree species identity and canopy cover on coffee pests and diseases, ii) the effect of climate and management on coffee berry disease and yield, iii) the impact of climate on a host-hyperparasite interaction, and iv) farmers’ perceptions of climate change and climate-mediated changes in disease dynamics and yield. I found that tree identity affected the incidence and severity of coffee diseases, whereas insect pests were strongly affected by canopy cover, but in a species-specific way (I). Both climate and management affected coffee berry disease and yield. Importantly, the effect of climatic variables on disease and yield differed strongly between the developmental stages from flowering to ripening (II). In chapter (III), I found that the climatic niches of coffee leaf rust and its hyperparasite differed, with coffee leaf rust severity preferring high maximum temperatures, whereas the hyperparasite preferred cold nights. The interviews revealed that the majority of farmers perceived long-term changes in one or more aspects of the climate, and the majority of farmers perceived an increase in coffee leaf rust and a decrease in coffee berry disease. Climate data also supported farmers’ knowledge on climate-disease-yield relationships (IV). Taken together, my thesis advances our understanding of the relationship between climate and management of coffee pests, diseases and yield, and this may contribute to the development of ecologically-informed pest and disease management strategies for coffee production and other agroforestry crops.
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| 7. |
- Barr, Anna E., et al.
(författare)
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Local habitat factors and spatial connectivity jointly shape an urban insect community
- 2021
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Ingår i: Landscape and Urban Planning. - : Elsevier BV. - 0169-2046 .- 1872-6062. ; 214
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Tidskriftsartikel (refereegranskat)abstract
- As the world becomes more and more urbanized, it is increasingly important to understand the impacts of urban landscapes on biodiversity. Urbanization can change local habitat factors and decrease connectivity among local habitats, with major impacts on the structure of natural food webs. However, most studies have focused on single species, or compared rural to urban habitats, which do not inform us on how to design and manage cities to optimize biodiversity. To understand the local and spatial drivers of ecological communities within urban landscapes, we assessed the relative impact of local habitat factors (sunlight exposure and leaf litter) and spatial connectivity on an oak-associated herbivore community within an urban landscape. From the local habitat factors, leaf litter but not sunlight exposure was related to herbivore species richness, with leaf litter contributing to the maintenance of high species richness on isolated trees. Guilds and species differed strongly in their response to local habitat factors and connectivity, resulting in predictable variation in insect community composition among urban oaks. Taken together, our study shows an interactive effect of local and spatial factors on species richness and species composition within an urban context, with guild- and species-specific life histories determining the response of insects to urban landscapes. To maintain biodiversity in the urban landscape, preserving a dense network of local habitats is essential. Moreover, allowing leaf litter to accumulate can be a simple, cost-effective conservation management practice.
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| 8. |
- Beche, Dinkissa, et al.
(författare)
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Prevalence of major pests and diseases in wild and cultivated coffee in Ethiopia
- 2023
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Ingår i: Basic and Applied Ecology. - 1439-1791 .- 1618-0089. ; 73, s. 3-9
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Tidskriftsartikel (refereegranskat)abstract
- The study of pests and diseases on crops and crop relatives in the wild is valuable from both a theoretical and an applied point of view. Few studies have addressed multiple pests and diseases in such ecosystems. Our objectives were to (1) compare the prevalence of multiple pests and diseases on coffee in forests and more managed landscapes and (2) assess how spatial, environmental, host density and management factors affect the incidence and severity of coffee pests and diseases across forests.To achieve these objectives we studied different pests, diseases and one hyperparasite on wild and semi-wild coffee from 84 plots of 20 × 20 m across a forested landscape in southwest Ethiopia and compared the results to previous studies of more intensively managed adjacent landscapes.The prevalence of all surveyed coffee leaf pests and diseases was high (>71% of investigated plots) and very similar to the levels in more intensively managed landscapes reported in the literature. The incidence rates of all pests, diseases and the hyperparasite showed a high variation among the plots, and correlation with each other in some cases. However, this variation was weakly related to the measured environmental and management variables, but coffee pests and diseases were often positively related to high coffee density.One possible explanation for the similar prevalence is that, although the landscapes are different, the local environmental conditions have much in common since coffee is also grown under indigenous shade trees in more intensively managed landscapes. However, the variability in pest and disease levels among sites was large and it is difficult to predict where they attain high levels. There is a need of detailed investigations on drivers of spatio-temporal population dynamics of these species, including their natural enemies, to be able to provide advice for development of sustainable coffee disease management.
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| 9. |
- Beche, Dinkissa, et al.
(författare)
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Spatial variation in human disturbances and their effects on forest structure and biodiversity across an Afromontane forest
- 2022
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Ingår i: Landscape Ecology. - : Springer Science and Business Media LLC. - 0921-2973 .- 1572-9761. ; 37:2, s. 493-510
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Tidskriftsartikel (refereegranskat)abstract
- Context Human disturbances can have large impacts on forest structure and biodiversity, and thereby result in forest degradation, a property difficult to detect by remote sensing.Objectives To investigate spatial variation in anthropogenic disturbances and their effects on forest structure and biodiversity.Methods In 144 plots of 20 x 20 m distributed across a forest area of 750 km2 in Southwest Ethiopia, we recorded: landscape variables (e.g., distance to forest edge), different human disturbances, forest structure variables, and species composition of trees and epiphyllous bryophytes. We then first assessed if landscape variables could explain the spatial distribution of disturbances. Second, we analysed how forest structure and biodiversity were influenced by disturbances.Results Human disturbances, such as coffee management and grazing declined with distance to forest edges, and penetrated at least a kilometer into the forest. Slope was not related to disturbance levels, but several types of disturbances were less common at higher elevations. Among human disturbance types, coffee management reduced liana cover and was associated with altered species composition of trees. The presence of large trees and basal area were not related to any of the disturbance gradients.Conclusions Although most anthropogenic disturbances displayed clear edge effects, surprisingly the variation in the chosen forest degradation indices were only weakly related to these disturbances. We suggest that the intersection between edge effects and forest degradation is very context specific and relies much on how particular societies use the forests. For example, in this landscape coffee management seems to be a key driver.
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| 10. |
- Burger, H. F., et al.
(författare)
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Bottom-up and top-down drivers of herbivory on Arabica coffee along an environmental and management gradient
- 2022
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Ingår i: Basic and Applied Ecology. - : Elsevier BV. - 1439-1791 .- 1618-0089. ; 59, s. 21-32
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Tidskriftsartikel (refereegranskat)abstract
- While sustainable agriculture relies on natural pest control, we lack insights into the relative importance of bottom-up and top-down factors on pest levels, especially along broad environmental and management gradients. To this aim, we focused on bottom-up and top-down control of herbivore damage in sixty sites in the centre of origin of Arabica coffee in southwestern Ethiopia, where coffee grows along a management gradient ranging from little or no management in the natural forest to commercial plantations. More specifically, we examined how canopy cover, percentage of surrounding forest and management intensity affected caffeine and chlorogenic acid concentration (bottom-up process) and attack of dummy caterpillars by ants and birds (top-down process), and how these in turn affected pest levels. Caffeine and chlorogenic acid concentrations were negatively related to canopy cover, while ant attack rate was positively related to canopy cover. Both ant and bird attack rate increased with the percentage of surrounding forest. Yet, secondary chemistry and caterpillar attack rates were unrelated to herbivory, and herbivory was only directly and positively affected by management intensity. Our study highlights that canopy cover can have contrasting effects on plant defence and predation, and that changes in bottom-up and top-down factors do – unlike often assumed – not necessarily translate into reduced pest levels. Instead, direct effects of management on pest levels may be more important than bottom-up or top-down mediated effects.
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