Modelling impacts of infrastructure and climatic factors on reindeer forage availability in winter

The cumulative impacts of climate change and human activities on species are often studied in isolation, limiting understanding of their combined effects. The present research addresses this limitation by proposing a novel conceptual model to assess the cumulative impacts of various anthropogenic developments and environmental conditions on ungulates. The conceptual model is applied to semi-domesticated reindeer, specifically in the context of winter grazing in northern Fennoscandia, as this species is facing an increasing range and intensity of stressors detrimental to its health and survival. The conceptual framework for the model is described, measuring forage loss due to physical, behavioural and climatic factors. Using data from previous studies, this framework is applied to assess loss of reindeer forage in winter pastures due to construction of roads, mines, hydropower stations and population centres. Results of this case study show that excluding behavioural impacts would lead to an 86 % underestimation of forage loss, while ignoring access limitations caused by snow conditions would result in an 11 % underestimation. Additionally, synergistic effects from multiple infrastructures impact 22 % of the area. Although the model does not yet account for factors like habitat connectivity or inter-annual weather variability, it provides a multi-faceted framework for evaluating cumulative impacts, offering a more holistic approach than existing models. Its adaptability also allows for application to other regions, species, or land-use scenarios. These findings emphasise the necessity of considering cumulative impacts within environmental impact assessments used to inform sustainable land-use and conservation strategies. • More comprehensive ecological models are needed to assess change. • Conceptual model assessing cumulative effects of infrastructure is outlined. • Excluding behaviour underestimates forage loss by 86 %. • Excluding climate underestimates forage loss by 11 %. • Synergistic factors make up 22 % of all impacts.