Christian Pedersen
Research Scientist
(+47) 974 34 123
christian.pedersen@nibio.no
Place
Ås O43
Visiting address
Oluf Thesens vei 43, 1433 Ås
Biography
I hold a Ph.D. in ecology and I am generally interested in the factors that shape population and community dynamics. I have worked for many years in arctic and alpine areas where my focus has been herbivore-plant interactions in relation to climate change. Currently my work focus on how land use and land use change in the agricultural landscape affect biodiversity, population dynamics and community composition using birds and plants as indicators. Main responsibilities include management of and reporting from the Norwegian monitoring program for agricultural landscapes, with particular focus on the development and use of indicators of biodiversity.
Abstract
Agricultural land abandonment is increasingly affecting rural and low-intensity farming regions across Europe, raising concerns about its impact on biodiversity. While some species may benefit from reduced human disturbance, many species in semi-natural ecosystem types depend on traditional agricultural management to maintain their ecological integrity. This study examines whether abandoned agricultural land in Norway contains semi-natural ecosystems that may hold important remnant populations of red-listed plant species and where continued cessation of farming may further threaten these biodiverse ecosystems. Using spatial data on abandoned farmland, semi-natural ecosystem types and species observations, we identify areas of conservation interest and assess the extent to which these areas support endangered species. In addition, we conducted a time-series analysis of vegetation change using NDVI data (2017–2024) to evaluate whether abandonment led to detectable ecological succession. We also analyzed the spatial distribution of abandonment and its correlation with proximity to active farms to understand regional patterns of abandonment. Our results show that only a small percentage (3.7 %) of the abandoned agricultural land considered in this study overlaps with known semi-natural ecosystem types, yet these areas support a significant number of red-listed plant species. The NDVI analysis revealed generally weak but positive greening trends, suggesting early successional changes that are not yet statistically significant across most habitat types. Our method thus suggests a potential approach to allocate limited management resources to key locations. At present, the amount of semi-natural ecosystems is probably underestimated, however, because of limited and time-consuming mapping activity. These findings emphasize the need for more extensive mapping and targeted conservation efforts and highlight the risks posed by abandonment in biodiversity rich semi-natural ecosystem types.
Authors
Diress Tsegaye Alemu Christian Pedersen Svein Olav Krøgli Anders Bryn Kerstin Potthoff Wenche DramstadAbstract
No abstract has been registered
Authors
Eric Post Elina Kaarlejärvi Marc Macias-Fauria David A. Watts Pernille Sporon Bøving Sean M. P. Cahoon R. Conor Higgins Christian John Jeffrey T. Kerby Christian Pedersen Mason Post Patrick F. SullivanAbstract
Biodiversity is declining globally in response to multiple human stressors, including climate forcing. Nonetheless, local diversity trends are inconsistent in some taxa, obscuring contributions of local processes to global patterns. Arctic tundra diversity, including plants, fungi, and lichens, declined during a 15-year experiment that combined warming with exclusion of large herbivores known to influence tundra vegetation composition. Tundra diversity declined regardless of experimental treatment, as background growing season temperatures rose with sea ice loss. However, diversity declined slower with large herbivores than without them. This difference was associated with an increase in effective diversity of large herbivores as formerly abundant caribou declined and muskoxen increased. Efforts that promote herbivore diversity, such as rewilding, may help mitigate impacts of warming on tundra diversity.
Abstract
No abstract has been registered
Abstract
The decline in farmland birds observed throughout Europe during recent decades has attracted much attention. Agricultural intensification or land abandonment are commonly forwarded as key drivers. Several countries have established agri-environmental schemes (AES) to counter these negative trends among farmland birds. This paper reports a study of the relationship between land use and bird species in the agricultural landscape of Norway. The main objective was to investigate the effect of spatial heterogeneity and diversity of land use on total richness and abundance of farmland birds at a national level. Monitoring the distribution and abundance of birds is part of the Norwegian monitoring programme for agricultural landscapes. The monitoring programme is based on mapping of 1 × 1 km squares distributed across the entire agricultural landscape. Within these squares permanent observation points are established for bird monitoring. Detailed interpretation of aerial photographs provides the land classification. We tested the relationship between landscape metrics at different levels of land type detail and species richness and abundance of farmland and non-farmland birds. There was a positive relationship between species richness and abundance of farmland birds and agricultural area. For non-farmland birds the relationship was negative. Spatial heterogeneity of land use was a significant positive factor for both farmland and non-farmland species. High land type diversity was positive for farmland bird richness, but negative for abundance. Non-farmland bird richness was not affected by land type diversity, but abundance had a negative response. The results presented in this paper highlight the importance of a spatial heterogeneous landscape. However, we also found that land type diversity could negatively affect the abundance of both farmland and non-farmland birds. Our findings suggest a need for different management approaches depending on whether the aim is increased species richness or abundance. Achieving both aims with the same means might be difficult. We thus suggest a need for land use analyses before proper management strategies can be implemented.
Authors
Christian PedersenAbstract
No abstract has been registered
Abstract
The study focuses on ecosystem services, historical aspects, and natural diversity. Specifically, it assesses possible proxies for investigating a set of cultural ecosystem services from the Norwegian agricultural landscape. Agricultural areas on the Norwegian land cover map surrounded by a 100 m wide buffer zone were analyzed for recorded historical buildings, cultural heritage sites, red-listed vascular plant species (defined as being at varying degrees at risk of extinction), and red-listed nature types (defined as endangered or vulnerable). The results indicate significant contributions from agricultural landscapes with respect to historical buildings, cultural heritage sites, and red-listed plant species. Regarding red-listed nature types, the contributions were diverse. The ecosystem proxies investigated showed increasing distribution trends with increasing proportions of agricultural landscapes in the spatial units, with a sharp increase with smaller area sizes. However, for cultural heritage sites the trend was different when the proportion of the agricultural landscape was below 25%; it showed a very slow increase. In conclusion, the study highlights the agricultural landscape’s diverse contributions to the investigated ecosystem services in Norway, prompting the need for further research on additional ecosystem services to ensure the continued delivery of environmental and social well-being.
Authors
Christian Pedersen Svein Olav Krøgli Shivesh Karan Svein Dale Grete Stokstad Diress Tsegaye AlemuAbstract
Over recent decades, farmland and meadow-breeding bird populations in Europe have markedly declined, attributed to factors like agricultural intensification and land abandonment. Parts of the Norwegian Monitoring Programme for Agricultural Landscapes explore the correlation between land use and bird species, aiming to understand how spatial heterogeneity and land use diversity affect the richness, abundance, and distribution of farmland birds. Between 2000 and 2023, we saw declining populations and reduced distributions of several farmland bird species within the monitoring squares. Additionally, we found that both spatial heterogeneity of land use and high land type diversity positively influenced farmland birds. This gives important insight on how to design biodiverse agricultural landscapes. We also examined the impact of agricultural intensity on 25 farmland bird species, using livestock density and pasture size as indicators. Larger pastures generally benefited a wide range of farmland bird species. Different bird species responded variably to livestock numbers, but high livestock density led to a decrease in overall farmland bird abundance. Many countries subsidize sustainable farming to protect biodiversity. We studied Norwegian agri-environmental schemes' impact on farmland and meadow-breeding birds. We found that bird observations rose when these measures were in place but often declined once the support ended. Furthermore, the schemes were geographically limited and relatively few farmers participated. While short-term benefits were evident, long-term effects remain uncertain, highlighting the need for improved conservation strategies. Emphasizing the importance of spatially heterogeneous agricultural landscapes with high land type diversity and natural areas, the study indicates the type of agricultural landscapes we should be aiming for to maintain and restore biodiversity.