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Mika Siljander is a University researcher at the University of Helsinki, where he received his Ph.D. in 2010. He has been working on geoinformatics projects for more than 20 years. His research interests includes species distribution, human–wildlife conflicts, land cover change, forest fires, and search and rescue services modelling. His current work is related to vectorborne diseases and COVID-19 (SARS-CoV-2) modelling.
Pogosta disease is a mosquito-borne infection, caused by Sindbis virus (SINV), which causes epidemics of febrile rash and arthritis in Northern Europe and South Africa. Resident grouse and migratory birds play a significant role as amplifying hosts and various mosquito species, including Aedes cinereus, Culex pipiens, Cx. torrentium and Culiseta morsitans are documented vectors. As specific treatments are not available for SINV infections, and joint symptoms may persist, the public health burden is considerable in endemic areas. To predict the environmental suitability for SINV infections in Finland, we applied a suite of geospatial and statistical modeling techniques to disease occurrence data. Using an ensemble approach, we first produced environmental suitability maps for potential SINV vectors in Finland. These suitability maps were then combined with grouse densities and environmental data to identify the influential determinants for SINV infections and to predict the risk of Pogosta disease in Finnish municipalities. Our predictions suggest that both the environmental suitability for vectors and the high risk of Pogosta disease are focused in geographically restricted areas. This provides evidence that the presence of both SINV vector species and grouse densities can predict the occurrence of the disease. The results support material for public-health officials when determining area-specific recommendations and deliver information to health care personnel to raise awareness of the disease among physicians.
Ruut Uusitalo; Mika Siljander; C. Culverwell; Guy Hendrickx; Andreas Lindén; Timothée Dub; Juha Aalto; Jussi Sane; Cedric Marsboom; Maija Suvanto; Andrea Vajda; Hilppa Gregow; Essi Korhonen; Eili Huhtamo; Petri Pellikka; Olli Vapalahti. Predicting Spatial Patterns of Sindbis Virus (SINV) Infection Risk in Finland Using Vector, Host and Environmental Data. International Journal of Environmental Research and Public Health 2021, 18, 7064 .
AMA StyleRuut Uusitalo, Mika Siljander, C. Culverwell, Guy Hendrickx, Andreas Lindén, Timothée Dub, Juha Aalto, Jussi Sane, Cedric Marsboom, Maija Suvanto, Andrea Vajda, Hilppa Gregow, Essi Korhonen, Eili Huhtamo, Petri Pellikka, Olli Vapalahti. Predicting Spatial Patterns of Sindbis Virus (SINV) Infection Risk in Finland Using Vector, Host and Environmental Data. International Journal of Environmental Research and Public Health. 2021; 18 (13):7064.
Chicago/Turabian StyleRuut Uusitalo; Mika Siljander; C. Culverwell; Guy Hendrickx; Andreas Lindén; Timothée Dub; Juha Aalto; Jussi Sane; Cedric Marsboom; Maija Suvanto; Andrea Vajda; Hilppa Gregow; Essi Korhonen; Eili Huhtamo; Petri Pellikka; Olli Vapalahti. 2021. "Predicting Spatial Patterns of Sindbis Virus (SINV) Infection Risk in Finland Using Vector, Host and Environmental Data." International Journal of Environmental Research and Public Health 18, no. 13: 7064.
With the simultaneous rise of concern about the climate crisis and the growing internationalization of research institutions, academic mobility poses an “academic paradox”: knowledge of the environmental harm of aviation does not necessarily translate into action. Universities must make changes to their mobility habits if they wish to comply with governmental carbon neutrality targets and lead with example. This research looks at Finland’s 14 universities and identifies the patterns and trends of academic mobility from a series of reports provided by the universities and their travel agencies. Moreover, we mapped the travel destinations to understand the scope of Finnish academic travel. The data revealed that Finnish universities are in different states of sustainability: some acting as clear trendsetters and others lagging. The results show that although the universities are performing well in some areas, as in preferring European destinations over intercontinental ones, there are still areas of improvement related to stopover reduction, the number of 1- and 2-day trips, and alternative transport forms to aviation. There is also a need for the standardization of targets and emission calculators. These key development areas are posed as recommendations through which the universities could easily reduce the carbon footprint of their mobility.
Veronica Ahonen; Mika Siljander; Petri Pellikka; Tino Johansson; Mikko Rask. The Sustainability of Academic Air Mobility in Finnish Universities. Sustainability 2021, 13, 2948 .
AMA StyleVeronica Ahonen, Mika Siljander, Petri Pellikka, Tino Johansson, Mikko Rask. The Sustainability of Academic Air Mobility in Finnish Universities. Sustainability. 2021; 13 (5):2948.
Chicago/Turabian StyleVeronica Ahonen; Mika Siljander; Petri Pellikka; Tino Johansson; Mikko Rask. 2021. "The Sustainability of Academic Air Mobility in Finnish Universities." Sustainability 13, no. 5: 2948.
In the Amazon rainforest, land use following deforestation is diverse and dynamic. Mounting evidence indicates that the climatic impacts of forest loss can also vary considerably, depending on specific features of the affected areas. The size of the deforested patches, for instance, was shown to modulate the characteristics of local climatic impacts. Nonetheless, the influence of different types of land use and management strategies on the magnitude of local climatic changes remains uncertain. Here, we evaluated the impacts of large-scale commodity farming and rural settlements on surface temperature, rainfall patterns, and energy fluxes. Our results reveal that changes in land–atmosphere coupling are induced not only by deforestation size but also, by land use type and management patterns inside the deforested areas. We provide evidence that, in comparison with rural settlements, deforestation caused by large-scale commodity agriculture is more likely to reduce convective rainfall and increase land surface temperature. We demonstrate that these differences are mainly caused by a more intensive management of the land, resulting in significantly lower vegetation cover throughout the year, which reduces latent heat flux. Our findings indicate an urgent need for alternative agricultural practices, as well as forest restoration, for maintaining ecosystem processes and mitigating change in the local climates across the Amazon basin.
Eduardo Eiji Maeda; Temesgen Alemayehu Abera; Mika Siljander; Luiz E. O. C. Aragão; Yhasmin Mendes de Moura; Janne Heiskanen. Large-scale commodity agriculture exacerbates the climatic impacts of Amazonian deforestation. Proceedings of the National Academy of Sciences 2021, 118, 1 .
AMA StyleEduardo Eiji Maeda, Temesgen Alemayehu Abera, Mika Siljander, Luiz E. O. C. Aragão, Yhasmin Mendes de Moura, Janne Heiskanen. Large-scale commodity agriculture exacerbates the climatic impacts of Amazonian deforestation. Proceedings of the National Academy of Sciences. 2021; 118 (7):1.
Chicago/Turabian StyleEduardo Eiji Maeda; Temesgen Alemayehu Abera; Mika Siljander; Luiz E. O. C. Aragão; Yhasmin Mendes de Moura; Janne Heiskanen. 2021. "Large-scale commodity agriculture exacerbates the climatic impacts of Amazonian deforestation." Proceedings of the National Academy of Sciences 118, no. 7: 1.
Savannahs provide valuable ecosystem services and contribute to continental and global carbon budgets. In addition, savannahs exhibit multiple land uses, e.g., wildlife conservation, pastoralism, and crop farming. Despite their importance, the effect of land use on woody aboveground biomass (AGB) in savannahs is understudied. Furthermore, fences used to reduce human–wildlife conflicts may affect AGB patterns. We assessed AGB densities and patterns, and the effect of land use and fences on AGB in a multi-use savannah landscape in southeastern Kenya. AGB was assessed with field survey and airborne laser scanning (ALS) data, and a land cover map was developed using Sentinel-2 satellite images in Google Earth Engine. The highest woody AGB was found in riverine forest in a conservation area and in bushland outside the conservation area. The highest mean AGB density occurred in the non-conservation area with mixed bushland and cropland (8.9 Mg·ha−1), while the lowest AGB density (2.6 Mg·ha−1) occurred in overgrazed grassland in the conservation area. The largest differences in AGB distributions were observed in the fenced boundaries between the conservation and other land-use types. Our results provide evidence that conservation and fences can create sharp AGB transitions and lead to reduced AGB stocks, which is a vital role of savannahs as part of carbon sequestration.
Edward Amara; Hari Adhikari; Janne Heiskanen; Mika Siljander; Martha Munyao; Patrick Omondi; Petri Pellikka. Aboveground Biomass Distribution in a Multi-Use Savannah Landscape in Southeastern Kenya: Impact of Land Use and Fences. Land 2020, 9, 381 .
AMA StyleEdward Amara, Hari Adhikari, Janne Heiskanen, Mika Siljander, Martha Munyao, Patrick Omondi, Petri Pellikka. Aboveground Biomass Distribution in a Multi-Use Savannah Landscape in Southeastern Kenya: Impact of Land Use and Fences. Land. 2020; 9 (10):381.
Chicago/Turabian StyleEdward Amara; Hari Adhikari; Janne Heiskanen; Mika Siljander; Martha Munyao; Patrick Omondi; Petri Pellikka. 2020. "Aboveground Biomass Distribution in a Multi-Use Savannah Landscape in Southeastern Kenya: Impact of Land Use and Fences." Land 9, no. 10: 381.
The numbers of reported human tick-borne encephalitis (TBE) cases in Europe have increased in several endemic regions (including Finland) in recent decades, indicative of an increasing threat to public health. As such, it is important to identify the regions at risk and the most influential factors associated with TBE distributions, particularly in understudied regions. This study aimed to identify the risk areas of TBE transmission in two different datasets based on human TBE disease cases from 2007 to 2011 (n = 86) and 2012–2017 (n = 244). We also examined which factors best explain the presence of human TBE cases. We used ensemble modelling to determine the relationship of TBE occurrence with environmental, ecological, and anthropogenic factors in Finland. Geospatial data including these variables were acquired from several open data sources and satellite and aerial imagery and, were processed in GIS software. Biomod2, an ensemble platform designed for species distribution modelling, was used to generate ensemble models in R. The proportion of built-up areas, field, forest, and snow-covered land in November, people working in the primary sector, human population density, mean precipitation in April and July, and densities of European hares, white-tailed deer, and raccoon dogs best estimated distribution of human TBE disease cases in the two datasets. Random forest and generalized boosted regression models performed with a very good to excellent predictive power (ROC = 0.89–0.96) in both time periods. Based on the predictive maps, high-risk areas for TBE transmission were located in the coastal regions in Southern and Western Finland (including the Åland Islands), several municipalities in Central and Eastern Finland, and coastal municipalities in Southern Lapland. To explore potential changes in TBE distributions in future climate, we used bioclimatic factors with current and future climate forecast data to reveal possible future hotspot areas. Based on the future forecasts, a slightly wider geographical extent of TBE risk was introduced in the Åland Islands and Southern, Western and Northern Finland, even though the risk itself was not increased. Our results are the first steps towards TBE-risk area mapping in current and future climate in Finland.
Ruut Uusitalo; Mika Siljander; Timothée Dub; Jussi Sane; Jani J. Sormunen; Petri Pellikka; Olli Vapalahti. Modelling habitat suitability for occurrence of human tick-borne encephalitis (TBE) cases in Finland. Ticks and Tick-borne Diseases 2020, 11, 101457 .
AMA StyleRuut Uusitalo, Mika Siljander, Timothée Dub, Jussi Sane, Jani J. Sormunen, Petri Pellikka, Olli Vapalahti. Modelling habitat suitability for occurrence of human tick-borne encephalitis (TBE) cases in Finland. Ticks and Tick-borne Diseases. 2020; 11 (5):101457.
Chicago/Turabian StyleRuut Uusitalo; Mika Siljander; Timothée Dub; Jussi Sane; Jani J. Sormunen; Petri Pellikka; Olli Vapalahti. 2020. "Modelling habitat suitability for occurrence of human tick-borne encephalitis (TBE) cases in Finland." Ticks and Tick-borne Diseases 11, no. 5: 101457.
Human–wildlife conflict (HWC) is a growing concern for local communities living in the vicinity of protected areas. These conflicts commonly take place as attack by wild animals and crop-raiding events, among other forms. We studied crop-raiding patterns by non-human primates in forest–agricultural landscape mosaic in the Taita Hills, southeast Kenya. The study applies both qualitative and quantitative methods. Semi-structured questionnaire was used in the primary data collection from the households, and statistical tests were performed. We used applied geospatial methods to reveal spatial patterns of crop-raiding by primates and preventive actions by farmers. The results indicate most of the farms experienced crop-raiding on a weekly basis. Blue monkey (Cercopithecus mitis) was the worst crop-raiding species and could be found in habitats covered by different land use/land cover types. Vervet monkey (Chlorocebus pygerythrus) and galagos crop-raided farms in areas with abundant tree canopy cover. Only few baboons (Papio cynocephalus) were reported to raid crops in the area. Results also show that the closer a farm is to the forest boundary and the less neighbouring farms there are between the farm and the forest, the more vulnerable it is for crop-raiding by blue monkeys, but not by any other studied primate species. The study could not show that a specific type of food crop in a farm or type of land use/land cover inside the wildlife corridor between the farmland and the forest boundary explain households’ vulnerability to crop-raiding by primates. Preventive actions against crop-raiding by farmers where taken all around the studied area in various forms. Most of the studied households rely on subsistence farming as their main livelihood and therefore crop-raiding by primates is a serious threat to their food security in the area.
Mika Siljander; Toini Kuronen; Tino Johansson; Martha Nzisa Munyao; Petri K.E. Pellikka. Primates on the farm – spatial patterns of human–wildlife conflict in forest-agricultural landscape mosaic in Taita Hills, Kenya. Applied Geography 2020, 117, 102185 .
AMA StyleMika Siljander, Toini Kuronen, Tino Johansson, Martha Nzisa Munyao, Petri K.E. Pellikka. Primates on the farm – spatial patterns of human–wildlife conflict in forest-agricultural landscape mosaic in Taita Hills, Kenya. Applied Geography. 2020; 117 ():102185.
Chicago/Turabian StyleMika Siljander; Toini Kuronen; Tino Johansson; Martha Nzisa Munyao; Petri K.E. Pellikka. 2020. "Primates on the farm – spatial patterns of human–wildlife conflict in forest-agricultural landscape mosaic in Taita Hills, Kenya." Applied Geography 117, no. : 102185.
There is a growing demand for geospatial technologies and skills in Kenya due to the ongoing devolution of government to the county level, development of GIS-based National Land Management Information System, and digitalization of information and maps to databases. Furthermore, the adaptation of agricultural production to the impacts of climate change, and its transition toward climate-smart landscape approach require support from geospatial technologies to stakeholders to sustainably manage land use interactions, such as soil, water, and nutrients along with agro-forestry, livestock, husbandry, and forest and grassland utilization at landscape level. A simple and visual Multifunctional Agricultural Landscape Mosaic (MALM) Story Map and Web Application was developed to support this transition and adoption of open access geospatial technology among the universities, government organizations, and NGOs in Kenya. The thematic content of the web application was designed to support climate change adaptation action planning in the target area with a focus on water resources, conservation agriculture, agro-forestry for the smallholder farms, and insect pest management. This chapter describes the emerging challenges of advancing geospatial technologies in Kenya, presents the results of a feasibility study of MALM and discusses its potential in supporting spatial planning and decision-making in climate change adaptation in the Taita Hills, southeast Kenya.
Tino Johansson; Janne Heiskanen; Mika Siljander; Petri Pellikka. Web Map Application to Support Spatial Planning, Decision-Making and Transition Toward Climate-Smart Landscapes in the Taita Hills, Kenya. Key Challenges in Geography 2019, 173 -187.
AMA StyleTino Johansson, Janne Heiskanen, Mika Siljander, Petri Pellikka. Web Map Application to Support Spatial Planning, Decision-Making and Transition Toward Climate-Smart Landscapes in the Taita Hills, Kenya. Key Challenges in Geography. 2019; ():173-187.
Chicago/Turabian StyleTino Johansson; Janne Heiskanen; Mika Siljander; Petri Pellikka. 2019. "Web Map Application to Support Spatial Planning, Decision-Making and Transition Toward Climate-Smart Landscapes in the Taita Hills, Kenya." Key Challenges in Geography , no. : 173-187.
Mosquitoes are vectors for numerous pathogens, which are collectively responsible for millions of human deaths each year. As such, it is vital to be able to accurately predict their distributions, particularly in areas where species composition is unknown. Species distribution modeling was used to determine the relationship between environmental, anthropogenic and distance factors on the occurrence of two mosquito genera, Culex Linnaeus and Stegomyia Theobald (syn. Aedes), in the Taita Hills, southeastern Kenya. This study aims to test whether any of the statistical prediction models produced by the Biomod2 package in R can reliably estimate the distributions of mosquitoes in these genera in the Taita Hills; and to examine which factors best explain their presence. Mosquito collections were acquired from 122 locations between January–March 2016 along transects throughout the Taita Hills. Environmental-, anthropogenic- and distance-based geospatial data were acquired from the Taita Hills geo-database, satellite- and aerial imagery and processed in GIS software. The Biomod2 package in R, intended for ensemble forecasting of species distributions, was used to generate predictive models. Slope, human population density, normalized difference vegetation index, distance to roads and elevation best estimated Culex distributions by a generalized additive model with an area under the curve (AUC) value of 0.791. Mean radiation, human population density, normalized difference vegetation index, distance to roads and mean temperature resulted in the highest AUC (0.708) value in a random forest model for Stegomyia distributions. We conclude that in the process towards more detailed species-level maps, with our study results, general assumptions can be made about the distribution areas of Culex and Stegomyia mosquitoes in the Taita Hills and the factors which influence their distribution.
Ruut Uusitalo; Mika Siljander; C. Lorna Culverwell; Noah C. Mutai; Kristian M. Forbes; Olli Vapalahti; Petri K.E. Pellikka. Predictive mapping of mosquito distribution based on environmental and anthropogenic factors in Taita Hills, Kenya. International Journal of Applied Earth Observation and Geoinformation 2018, 76, 84 -92.
AMA StyleRuut Uusitalo, Mika Siljander, C. Lorna Culverwell, Noah C. Mutai, Kristian M. Forbes, Olli Vapalahti, Petri K.E. Pellikka. Predictive mapping of mosquito distribution based on environmental and anthropogenic factors in Taita Hills, Kenya. International Journal of Applied Earth Observation and Geoinformation. 2018; 76 ():84-92.
Chicago/Turabian StyleRuut Uusitalo; Mika Siljander; C. Lorna Culverwell; Noah C. Mutai; Kristian M. Forbes; Olli Vapalahti; Petri K.E. Pellikka. 2018. "Predictive mapping of mosquito distribution based on environmental and anthropogenic factors in Taita Hills, Kenya." International Journal of Applied Earth Observation and Geoinformation 76, no. : 84-92.
African mountains are characterized by high levels of biodiversity and provide ecosystem services to millions of people. Due to steep environmental gradients, growing human populations and geographical isolation, these coupled socio-ecological systems are highly vulnerable to climate change impacts. The capacity of local stakeholders to anticipate future changes and to assess their potential impacts is paramount for enhancing adaptation and resilience. Here we apply a participatory scenario development framework in two parts of the Eastern Afromontane Biodiversity Hotspot: Taita Hills in Kenya and Jimma rural area in Ethiopia. In each area, we facilitated local stakeholders in envisioning adaptation scenarios under projected climate changes by mid-21st century, and assessed the potential impacts of these pathways on land use and land cover. In the Taita Hills, under a business-as-usual scenario, human population and activities concentrate at high elevation, triggering cascade effects on remnant forest cover, biodiversity and ecosystem services. Alternative adaptation scenarios envisage reforestation associated with either improved agricultural practices or ecosystem restoration. In the Jimma area, rising temperatures are expected to disrupt traditional coffee production under a business-as-usual scenario, resulting in the loss of coffee-forest canopies and reduction of forest-dependent biodiversity. Alternative adaptation scenarios envisage either expansion of commercial coffee plantations or expansion of agroforestry, including traditional coffee farming. In the both Taita and Jimma, adaptation pathways present trade-offs between provisioning, supporting and regulating services, and between livelihoods and biodiversity conservation. Our findings encourage the use of multidisciplinary, bottom-up approaches for developing locally tailored, climate-smart and sustainable adaptation pathways.
Claudia Capitani; Weyessa Garedew; Amsalu Mitiku; Gezahegn Berecha; Binyam Tesfau Hailu; Janne Heiskanen; Pekka Hurskainen; Philip J. Platts; Mika Siljander; Fabrice Pinard; Tino Johansson; Robert Marchant. Views from two mountains: exploring climate change impacts on traditional farming communities of Eastern Africa highlands through participatory scenarios. Sustainability Science 2018, 14, 191 -203.
AMA StyleClaudia Capitani, Weyessa Garedew, Amsalu Mitiku, Gezahegn Berecha, Binyam Tesfau Hailu, Janne Heiskanen, Pekka Hurskainen, Philip J. Platts, Mika Siljander, Fabrice Pinard, Tino Johansson, Robert Marchant. Views from two mountains: exploring climate change impacts on traditional farming communities of Eastern Africa highlands through participatory scenarios. Sustainability Science. 2018; 14 (1):191-203.
Chicago/Turabian StyleClaudia Capitani; Weyessa Garedew; Amsalu Mitiku; Gezahegn Berecha; Binyam Tesfau Hailu; Janne Heiskanen; Pekka Hurskainen; Philip J. Platts; Mika Siljander; Fabrice Pinard; Tino Johansson; Robert Marchant. 2018. "Views from two mountains: exploring climate change impacts on traditional farming communities of Eastern Africa highlands through participatory scenarios." Sustainability Science 14, no. 1: 191-203.
Understanding how species are distributed in space and time is a focal element guiding conservational efforts under ongoing climate change and the Holocene extinction. Freshwater habitats are currently one of the most threatened ecosystem types, and studies aiming to unravel factors that govern biodiversity of tropical stream micro-organisms are especially scarce. Diatoms play an important role as primary producers in streams and are widely used as ecological indicators. However, relatively little is known about which factors affect diatom communities in the tropics. Here, we studied benthic diatom diversity across 67 tropical streams spanning stream orders 1–5 in Kenya. We examined whether the hypothesis of latitudinal diversity gradient applies for benthic diatoms, i.e. whether tropical streams encompass more species than boreal streams using a comparable boreal dataset. In addition, we studied which environmental, land use and spatial factors control benthic diatom communities using redundancy analysis. We also examined the nestedness and turnover components of beta diversity, factors contributing to diatom species richness, and the uniqueness of the communities across stream orders by using boosted regression trees and local contribution to beta diversity. Finally, we studied whether environmental heterogeneity and beta diversity are related across stream orders and tested their relationship using tests of homogeneity of dispersion and regression analysis. Species richness was not higher in tropical streams than in boreal ones. Tropical diatom communities were controlled jointly by local environmental and spatial factors. Although water chemistry was the most important controlling factor, also physical variables contributed significantly to community variation. Land use had also a significant effect on diatom communities as broad leaved forest streams harboured different diatom communities compared with streams with higher human impact and conductivity, stressing the importance of forests to water quality and diatom biodiversity. Headwater streams encompassed the highest species turnover, whereas nestedness was higher in higher order streams. Species richness was significantly higher in higher order streams than in headwaters, whereas the uniqueness of the communities peaked in headwaters. Environmental heterogeneity was the highest in headwater streams and was related to high beta diversity, which highlights the importance of habitat heterogeneity to biodiversity. Our results stress the management and conservational importance of headwater streams and tropical montane forests as these environments harbour unique diatom communities important for regional diversity.
Jenny Jyrkänkallio-Mikkola; Mika Siljander; Vuokko Heikinheimo; Petri Pellikka; Janne Soininen. Tropical stream diatom communities – The importance of headwater streams for regional diversity. Ecological Indicators 2018, 95, 183 -193.
AMA StyleJenny Jyrkänkallio-Mikkola, Mika Siljander, Vuokko Heikinheimo, Petri Pellikka, Janne Soininen. Tropical stream diatom communities – The importance of headwater streams for regional diversity. Ecological Indicators. 2018; 95 ():183-193.
Chicago/Turabian StyleJenny Jyrkänkallio-Mikkola; Mika Siljander; Vuokko Heikinheimo; Petri Pellikka; Janne Soininen. 2018. "Tropical stream diatom communities – The importance of headwater streams for regional diversity." Ecological Indicators 95, no. : 183-193.
Land cover change takes place in sub-Saharan Africa as forests and shrublands are converted to agricultural lands in order to meet the needs of growing population. Changes in land cover also impact carbon sequestration in vegetation cover with an influence on climate on continental scale. The impact of land cover change on tree aboveground carbon stocks was studied in Taita Hills, Kenya. The land cover change between 1987 and 2011 for four points of time was assessed using SPOT satellite imagery, while the carbon density in various land cover types was assessed with field measurements, allometric biomass functions and airborne laser scanning data. Finally, the mean carbon densities of land cover types were combined with land cover maps resulting in carbon stock values for given land cover types for each point of time studied. Expansion of croplands has been taking place since 1987 and before on the cost of thickets and shrublands, especially on the foothills and lowlands. Due to the land cover changes, the carbon stock of trees was decreasing until 2003, after which there has been an increase. The findings of the research is supported by forest transition model, which emphasizes increase of awareness of forests' role in providing ecosystem services, such as habitats for pollinators, water harvesting and storage at the same time when economic reasons in making land-use choices between cropland and woodland, and governmental legislation supports trees on farms.
P.K.E. Pellikka; V. Heikinheimo; J. Hietanen; E. Schäfer; Mika Siljander; J. Heiskanen. Impact of land cover change on aboveground carbon stocks in Afromontane landscape in Kenya. Applied Geography 2018, 94, 178 -189.
AMA StyleP.K.E. Pellikka, V. Heikinheimo, J. Hietanen, E. Schäfer, Mika Siljander, J. Heiskanen. Impact of land cover change on aboveground carbon stocks in Afromontane landscape in Kenya. Applied Geography. 2018; 94 ():178-189.
Chicago/Turabian StyleP.K.E. Pellikka; V. Heikinheimo; J. Hietanen; E. Schäfer; Mika Siljander; J. Heiskanen. 2018. "Impact of land cover change on aboveground carbon stocks in Afromontane landscape in Kenya." Applied Geography 94, no. : 178-189.
Binyam Tesfaw Hailu; Mika Siljander; Eduardo E. Maeda; Petri Pellikka. Assessing spatial distribution of Coffea arabica L. in Ethiopia's highlands using species distribution models and geospatial analysis methods. Ecological Informatics 2017, 42, 79 -89.
AMA StyleBinyam Tesfaw Hailu, Mika Siljander, Eduardo E. Maeda, Petri Pellikka. Assessing spatial distribution of Coffea arabica L. in Ethiopia's highlands using species distribution models and geospatial analysis methods. Ecological Informatics. 2017; 42 ():79-89.
Chicago/Turabian StyleBinyam Tesfaw Hailu; Mika Siljander; Eduardo E. Maeda; Petri Pellikka. 2017. "Assessing spatial distribution of Coffea arabica L. in Ethiopia's highlands using species distribution models and geospatial analysis methods." Ecological Informatics 42, no. : 79-89.
Afromontane tropical forests maintain high biodiversity and provide valuable ecosystem services, such as carbon sequestration. The spatial distribution of aboveground biomass (AGB) in forest-agriculture landscape mosaics is highly variable and controlled both by physical and human factors. In this study, the objectives were (1) to generate a map of AGB for the Taita Hills, in Kenya, based on field measurements and airborne laser scanning (ALS), and (2) to examine determinants of AGB using geospatial data and statistical modelling. The study area is located in the northernmost part of the Eastern Arc Mountains, with an elevation range of approximately 600–2200 m. The field measurements were carried out in 215 plots in 2013–2015 and ALS flights conducted in 2014–2015. Multiple linear regression was used for predicting AGB at a 30 m × 30 m resolution based on canopy cover and the 25th percentile height derived from ALS returns (R2 = 0.88, RMSE = 52.9 Mg ha−1). Boosted regression trees (BRT) were used for examining the relationship between AGB and explanatory variables at a 250 m × 250 m resolution. According to the results, AGB patterns were controlled mainly by mean annual precipitation (MAP), the distribution of croplands and slope, which explained together 69.8% of the AGB variation. The highest AGB densities have been retained in the semi-natural vegetation in the higher elevations receiving more rainfall and in the steep slope, which is less suitable for agriculture. AGB was also relatively high in the eastern slopes as indicated by the strong interaction between slope and aspect. Furthermore, plantation forests, topographic position and the density of buildings had a minor influence on AGB. The findings demonstrate the utility of ALS-based AGB maps and BRT for describing AGB distributions across Afromontane landscapes, which is important for making sustainable land management decisions in the region.
Hari Adhikari; Janne Heiskanen; Mika Siljander; Eduardo Maeda; Vuokko Heikinheimo; Petri K. E. Pellikka. Determinants of Aboveground Biomass across an Afromontane Landscape Mosaic in Kenya. Remote Sensing 2017, 9, 827 .
AMA StyleHari Adhikari, Janne Heiskanen, Mika Siljander, Eduardo Maeda, Vuokko Heikinheimo, Petri K. E. Pellikka. Determinants of Aboveground Biomass across an Afromontane Landscape Mosaic in Kenya. Remote Sensing. 2017; 9 (8):827.
Chicago/Turabian StyleHari Adhikari; Janne Heiskanen; Mika Siljander; Eduardo Maeda; Vuokko Heikinheimo; Petri K. E. Pellikka. 2017. "Determinants of Aboveground Biomass across an Afromontane Landscape Mosaic in Kenya." Remote Sensing 9, no. 8: 827.
Mika Siljander; Emilia Venäläinen; Floris Goerlandt; Petri Pellikka. GIS-based cost distance modelling to support strategic maritime search and rescue planning: A feasibility study. Applied Geography 2015, 57, 54 -70.
AMA StyleMika Siljander, Emilia Venäläinen, Floris Goerlandt, Petri Pellikka. GIS-based cost distance modelling to support strategic maritime search and rescue planning: A feasibility study. Applied Geography. 2015; 57 ():54-70.
Chicago/Turabian StyleMika Siljander; Emilia Venäläinen; Floris Goerlandt; Petri Pellikka. 2015. "GIS-based cost distance modelling to support strategic maritime search and rescue planning: A feasibility study." Applied Geography 57, no. : 54-70.
Tree species regeneration determines future forest structure and composition, but is often severely hampered in small forest relicts. To study succession, long-term field observations or simulation models are used but data, knowledge or resources to run such models are often scarce in tropical areas. We propose and implement a species accounting equation, which includes the co-occurring events extinction, colonization and recruitment and which can be solved by using data from a single inventory. We solved this species accounting equation for the 12 remaining Afromontane cloud forest relicts in Taita Hills, Kenya by comparing the tree species present among the seedling, sapling and mature tree layer in 82 plots. A simultaneous ordination of the seedling, sapling and mature tree layer data revealed that potential species extinctions, colonizations and recruitments may induce future species shifts. On landscape level, the potential extinction debt amounted to 9% (7 species) of the regional species pool. On forest relict level, the smallest relicts harbored an important proportion of the tree species diversity in the regeneration layer. The average potential recruitment credit, defined as species only present as seedling or sapling, was 3 and 6 species for large and small forest relicts, while the average potential extinction debt was 12 and 4 species, respectively. In total, both large and small relicts are expected to lose approximately 20% of their current local tree species pool. The species accounting equations provide a time and resource effective tool and give an improved understanding of the conservation status and possible future succession dynamics of forest relicts, which can be particularly useful in a context of participatory monitoring
Koen W. Thijs; Raf Aerts; Winfred Musila; Mika Siljander; Erik Matthysen; Luc Lens; Petri Pellikka; Hubert Gulinck; Bart Muys. Potential tree species extinction, colonization and recruitment in Afromontane forest relicts. Basic and Applied Ecology 2014, 15, 288 -296.
AMA StyleKoen W. Thijs, Raf Aerts, Winfred Musila, Mika Siljander, Erik Matthysen, Luc Lens, Petri Pellikka, Hubert Gulinck, Bart Muys. Potential tree species extinction, colonization and recruitment in Afromontane forest relicts. Basic and Applied Ecology. 2014; 15 (4):288-296.
Chicago/Turabian StyleKoen W. Thijs; Raf Aerts; Winfred Musila; Mika Siljander; Erik Matthysen; Luc Lens; Petri Pellikka; Hubert Gulinck; Bart Muys. 2014. "Potential tree species extinction, colonization and recruitment in Afromontane forest relicts." Basic and Applied Ecology 15, no. 4: 288-296.
Petri K.E. Pellikka; Barnaby J.F. Clark; Alemu Gonsamo Gosa; Nina Himberg; Pekka Hurskainen; Eduardo Maeda; James Mwang’Ombe; Loice M.A. Omoro; Mika Siljander. Agricultural Expansion and Its Consequences in the Taita Hills, Kenya. Developments in Earth Surface Processes 2013, 165 -179.
AMA StylePetri K.E. Pellikka, Barnaby J.F. Clark, Alemu Gonsamo Gosa, Nina Himberg, Pekka Hurskainen, Eduardo Maeda, James Mwang’Ombe, Loice M.A. Omoro, Mika Siljander. Agricultural Expansion and Its Consequences in the Taita Hills, Kenya. Developments in Earth Surface Processes. 2013; ():165-179.
Chicago/Turabian StylePetri K.E. Pellikka; Barnaby J.F. Clark; Alemu Gonsamo Gosa; Nina Himberg; Pekka Hurskainen; Eduardo Maeda; James Mwang’Ombe; Loice M.A. Omoro; Mika Siljander. 2013. "Agricultural Expansion and Its Consequences in the Taita Hills, Kenya." Developments in Earth Surface Processes , no. : 165-179.
Persistence of forest-dependent species in fragmented landscapes strongly relies on sufficient dispersal between patches, making it important to understand how animal movements are affected by the intervening matrix. Movements can be influenced through selection or avoidance of land cover based on their perceived suitability for foraging or providing cover. The composition and configuration of the matrix will, therefore, most likely be an important factor to consider when estimating connectivity between patches. To address this, we performed translocation experiments to understand how forest birds used different land cover types in a fine-grained matrix of a fragmented Afromontane biodiversity hot spot (Taita Hills, Kenya). Our results revealed that use of land cover types for both the forest specialist Cabanis's greenbul Phyllastrephus cabanisi and for the forest generalist white-starred robin Pogonocichla stellata was disproportional to their availability. However, this effect was influenced by matrix configuration; in patchy matrices, land cover selection was more pronounced compared with more uniform matrices, especially for the forest specialist. At the scale of movement steps, risk avoidance seemed to be a strong factor in the route decisions for both species. Observed steps contained on average lower proportions of open land cover and did less frequently intersect built-up areas than expected. P. stellata did not differentiate between the alternative land cover types, whereas P. cabanisi preferred steps that contained more indigenous forest. The observed negative relationship between degree of forest dependency and matrix permeability implies that for members of the Taita bird community, which are even more dependent on intact forest habitat (i.e. the critically endangered Taita thrush Turdus helleri), current permeability of the matrix may be even lower. Matrix restoration to improve connectivity may, therefore, be a crucial instrument for the long-term survival of forest-dependent species in these fragmented Afromontane landscapes.
Job Aben; F. Adriaensen; K. W. Thijs; P. Pellikka; M. Siljander; Luc Lens; E. Matthysen. Effects of matrix composition and configuration on forest bird movements in a fragmented Afromontane biodiversity hot spot. Animal Conservation 2012, 15, 658 -668.
AMA StyleJob Aben, F. Adriaensen, K. W. Thijs, P. Pellikka, M. Siljander, Luc Lens, E. Matthysen. Effects of matrix composition and configuration on forest bird movements in a fragmented Afromontane biodiversity hot spot. Animal Conservation. 2012; 15 (6):658-668.
Chicago/Turabian StyleJob Aben; F. Adriaensen; K. W. Thijs; P. Pellikka; M. Siljander; Luc Lens; E. Matthysen. 2012. "Effects of matrix composition and configuration on forest bird movements in a fragmented Afromontane biodiversity hot spot." Animal Conservation 15, no. 6: 658-668.
This study presents a predictive modelling technique to map population distribution and abundance for rural areas in Africa. Prediction models were created using a generalized regression analysis and spatial prediction (GRASP) method that uses the generalized additive model (GAM) regression technique. Dwelling unit presence–absence was mapped from airborne images covering 98 km2 (30% of the study area) and used as a response variable. Remote-sensing-based (reflectance, texture and land cover) and geospatial (topography, climate and distance) data were used as predictors. For the rest of the study area (228 km2; 70%), GAM models were extrapolated, and prediction maps constructed. Model performance was measured as explanatory power (adj.D 2, adjusted deviance change), predictive power (area under the receiver operator curve, AUC) and kappa value (κ). GAM models explained 19–31% of the variation in dwelling-unit occurrence and 28–47% of the variation in human population abundance. The predictive power for population distribution GAM models was good (AUC of 0.80–0.86). This study shows that for the prediction of dwelling-unit distribution and for human population abundance, the best modelling performance was achieved using combined geospatial- and remote-sensing-based predictor variables. The best predictors for modelling the variability in human population distribution using combined predictors were angular second moment image-texture measurement, precipitation, mean elevation, surface reflectance for Satellite Pour l'Observation de la Terre (SPOT) red and near-infrared (NIR) bands, correlation image-texture measurement and distance to roads, respectively. The population-abundance modelling result was compared with two existing global population datasets: Gridded Population of the World version 3 (GPWv3) and LandScan 2005. The result showed that for regional and local-scale population-estimation probability, models created using remotely sensed and geospatial data were superior compared to GPWv3 or LandScan 2005 data products. Population models had high correlation with Kenyan population census data for 1999 in mountainous sub-locations and low correlation for sub-locations that also extended into the lowlands.
M. Siljander; B. J. F. Clark; P. K. E. Pellikka. A predictive modelling technique for human population distribution and abundance estimation using remote-sensing and geospatial data in a rural mountainous area in Kenya. International Journal of Remote Sensing 2011, 32, 5997 -6023.
AMA StyleM. Siljander, B. J. F. Clark, P. K. E. Pellikka. A predictive modelling technique for human population distribution and abundance estimation using remote-sensing and geospatial data in a rural mountainous area in Kenya. International Journal of Remote Sensing. 2011; 32 (21):5997-6023.
Chicago/Turabian StyleM. Siljander; B. J. F. Clark; P. K. E. Pellikka. 2011. "A predictive modelling technique for human population distribution and abundance estimation using remote-sensing and geospatial data in a rural mountainous area in Kenya." International Journal of Remote Sensing 32, no. 21: 5997-6023.
Water resources and land use are closely linked with each other and with regional climate, assembling a very complex system. The understanding of the interconnecting relations involved in this system is an essential step for elaborating public policies that can effectively lead to the sustainable use of water resources. In this study, an integrated modelling framework was assembled in order to investigate potential impacts of agricultural expansion and climate changes on Irrigation Water Requirements (IWR) in the Taita Hills, Kenya. The framework comprised a land use change simulation model, a reference evapotranspiration model and synthetic precipitation datasets generated through a Monte Carlo simulation. In order to generate plausible climate change scenarios, outputs from General Climate Models were used as reference to perturbing the Monte Carlo simulations. The results indicate that throughout the next 20 years the low availability of arable lands in the hills will drive agricultural expansion to areas with higher IWR in the foothills. If current trends persist, agricultural areas will occupy roughly 60% of the study area by 2030. This expansion will increase by approximately 40% the annual water volume necessary for irrigation. Climate change may slightly decrease crops' IWR in April and November by 2030, while in May a small increase will likely be observed. The integrated assessment of these environmental changes allowed a clear identification of priority regions for land use allocation policies and water resources management.
Eduardo Eiji Maeda; Petri K.E. Pellikka; Barnaby J.F. Clark; Mika Siljander. Prospective changes in irrigation water requirements caused by agricultural expansion and climate changes in the eastern arc mountains of Kenya. Journal of Environmental Management 2010, 92, 982 -993.
AMA StyleEduardo Eiji Maeda, Petri K.E. Pellikka, Barnaby J.F. Clark, Mika Siljander. Prospective changes in irrigation water requirements caused by agricultural expansion and climate changes in the eastern arc mountains of Kenya. Journal of Environmental Management. 2010; 92 (3):982-993.
Chicago/Turabian StyleEduardo Eiji Maeda; Petri K.E. Pellikka; Barnaby J.F. Clark; Mika Siljander. 2010. "Prospective changes in irrigation water requirements caused by agricultural expansion and climate changes in the eastern arc mountains of Kenya." Journal of Environmental Management 92, no. 3: 982-993.
The Taita Hills are the northernmost part of the Eastern Arc Mountains of Kenya and Tanzania, which is one of the most important regions for biological conservation in the world. The indigenous cloud forests in this area have suffered substantial degradation for several centuries due to agricultural expansion. In the Taita Hills, currently only 1% of the original forested area remains preserved. In order to create effective policies to preserve the natural resources and biodiversity of the Eastern Arc Mountains it is crucial to understand the causes and interactions involved in the landscape changes in the most degraded areas. The research presented here aimed to understand the role of landscape attributes and infrastructure components as driving forces of agricultural expansion in the Taita Hills. Geospatial technology tools and a landscape dynamic simulation model were integrated to identify and evaluate the driving forces of agricultural expansion and simulate future landscape scenarios. The results indicate that, if current trends persist, agricultural areas will occupy roughly 60% of the study area by 2030. Agricultural expansion will likely take place predominantly in lowlands and foothills throughout the next 20 years, increasing the spatial dependence on distance to rivers and other water bodies. The main factors driving the spatial distribution of new croplands were the distance to markets, proximity to already established agricultural areas and distance to roads. Other driving forces of the agricultural expansion, as well as their implications for natural resources conservation, are discussed. Further studies are necessary to integrate the effects of population pressure and climate change on the sustainability and characteristics of local agricultural systems.
Eduardo Eiji Maeda; Barnaby J.F. Clark; Petri Pellikka; Mika Siljander. Modelling agricultural expansion in Kenya’s Eastern Arc Mountains biodiversity hotspot. Agricultural Systems 2010, 103, 609 -620.
AMA StyleEduardo Eiji Maeda, Barnaby J.F. Clark, Petri Pellikka, Mika Siljander. Modelling agricultural expansion in Kenya’s Eastern Arc Mountains biodiversity hotspot. Agricultural Systems. 2010; 103 (9):609-620.
Chicago/Turabian StyleEduardo Eiji Maeda; Barnaby J.F. Clark; Petri Pellikka; Mika Siljander. 2010. "Modelling agricultural expansion in Kenya’s Eastern Arc Mountains biodiversity hotspot." Agricultural Systems 103, no. 9: 609-620.