Abstract :
[en] Norway recently adopted a ‘Quality norm’ system to assess the status of wild reindeer (Rangifer tarandus). Each of the 24 management areas is assessed based on three parameters, one of which is human impact on habitats - currently a major threat. After the classification, further processes (“impact analysis” and “mitigation plans”) need to identify anthropogenic drivers, identify and implement targeted mitigation measures to ensure that each area meets quality standards sufficient to maintain viable reindeer populations for future generations. Statistical models developed in the past decades based on reindeer GPS data can be used to support these processes in all reindeer areas by:
• assessing the cumulative impact of human activities
• providing estimates and maps of suitable areas (both today, and as they were before the
development of human infrastructure), barriers to movement, and of human footprint
• providing estimates and high-resolution maps of functional habitats and corridors
• performing scenario analyses to simulate the effect of mitigation measures
This report supports these processes in Reinheimen - the northern part of the Reinheimen-Breheimen wild reindeer area. Until recently the entirety of Reinheimen was used by reindeer. In the last decades however, no observations were recorded in the area of Puttbudalen, especially in the calving season, and there are concerns that the largest herd located in the southern part of Reinheimen may no longer be functionally connected to the smaller, northern herd. The report first presents estimates and maps of habitat quality, barriers, human footprint, connectivity and cumulative impacts. After, it presents scenario analyses that simulate the efficacy of suggested mitigation measures, consisting of the closure of the tourist cabin Pyttbua and related trails and ski tracks, and of the closure of a road by creating a parking place at “Kabben”. Although no GPS data were available in Reinheimen-Breheimen, the models appear to be robust, as they fit quite well with both local knowledge, a database of reindeer observations (“sett rein”), and a database of ancient pitfall traps. The models show that:
• Reinheimen provides good amounts of suitable habitat for all seasons, especially clustered
in the southern part, around Lordalen. Conversely, in the north, and south-west of Pyttbua,
the habitat is more fragmented, especially in winter and early spring. This is due to challenging
topography, high peaks, glaciers, and a network of tourist infrastructure.
• Habitat quality and connectivity were much higher before the development of human infrastructure especially in the large valleys south, and just outside the wild reindeer area boundaries. While these valleys were especially suitable as calving areas, now the network of roads, settlements and cabins causes a high human footprint, and creates barriers to movements. Puttbudalen also has a high footprint, especially during calving.
• The axe Brøstdalen-Puttbudalen Grotli-Torddalen represents the upper limit of the most functional calving grounds in the southern part of Reinheimen, which seem no longer functionally connected to the smaller and more fragmented calving areas north. The same pattern can be seen also in other seasons, though it is least evident in summer.
• The most robust corridors are concentrated south of the Brøstdalen-Puttbudalen Grotli-
Torddalen axe. In summer reindeer have more movement options compared to other seasons, but it is unclear to which degree they can still traverse the above-mentioned axe.
Movement options decrease especially in calving. Possible corridors connecting all functional areas in Reinheimen would most likely have to pass through a bottleneck in proximity of Brøstdalen-Puttbudalen - either reindeer would traverse the valley, or move by Pyttbua directed towards Reindalseter; alternatively, reindeer would have to follow narrow and long corridors in western edge of the reindeer area, again towards Reindalseter. The models therefore confirm the expectations of the client, and indicate Brøstdalen-Puttbudalen as a critical bottleneck to maintain connectivity in Reinheimen
Scenario 2, which consists in closing Pyttbua and related trails and ski tracks, and placing a barrier on the rod in locality Kabben, is by far the most efficient og the alternatives tested. Scenario 2 is expected to improve both the suitability of the area – and thus its expected use – as well as increasing the likelihood of restoring the connection with the northern area. The improvements are expected especially during the calving period and in spring- early summer. After implementation of Scenario 2, these are the expected outcomes:
• Functional calving habitat increases by 16.98 km² and becomes 5.97% more connected
• Spring migration opportunities increase 4,13%
• Summer habitat increases (+13,52 km²), becomes more connected (+2,64%) and better connected to calving grounds (+4,13%)
• Winter habitat and connectivity increase by +8,08 km² and 2,06% respectively
In conclusion, the results confirm that Scenario 2 represents an adequate mitigation measure. This however requires that disturbance in the area is kept very low, especially during calving and early summer. It is likely that the efficacy of Scenario 2 is actually underestimated, and would be higher if considering connectivity in the entire Reinheimen-Breheimen area, rather than Reinheimen alone. The model also indicates some bottlenecks in proximity of the location suggested for building the parking place in Kabben. Note that the models are built at 100 m resolution, and while the overall picture is reliable, the exact location of the corridors might be locally imprecise. We recommend
local investigations to verify the precise location of possible passages for reindeer, in order to define the best location for a road barrier and parking place. We also recommend being ambitious when planning the mitigation measures. Reindeer no longer use the area, and there are no guarantee that lost corridors can be recuperated. It is advisable to “free” the area as much as possible from human disturbance in all seasons, to encourage the re-establishment of the lost tradition to use the area. Disturbance should therefore
be kept at a minimum, and useful measures might include tourism, traffic and hunting restriction. We also recommend considering other mitigation measures, to ensure that entire corridors are maintained functional, from start to end. We also recommend developing a plan to re-direct tourists that would no longer go to Pyttbua, and to consider carefully cabin development also along the valleys outside the boundaries of the wild reindeer area. Last, if the aim is to promote connectivity throughout Reindheimen-Breheimen, we also recommend considering other mitigation measures, for instance in Breiddalen. The report provides several 2D and 3D visualization of functional areas and corridors, from different perspectives, and with overlaid reindeer observations and data on ancient pitfall traps to document actual movement possibilities for reindeer. We hope that this effort helps obtaining a good understanding of reindeer connectivity in the entire Reinheimen, from a “bird eye view”, and that this knowledge could enable taking better informed management decisions to ensure long-term population viability.
