LAND: Delimiting functional management units for partially migratory deer populations (DeerUnit)

A global challenge for the management of large mammals is that current management units are typically too small to capture the entire migration cycle. Our aim was to understand the underlying of drivers migration, predict future habitat suitability of seasonal ranges under climate change, in order to enable demarcation of functional population units based on data on the full migration cycle of 496 red deer. (WP1) We have determined the timing and scale of mismatch between biological space use and management units at two different administrative levels, the governmental level (municipalities) and the local management units (MU) (J Appl Ecol 2018). While individual range use clearly exceeded the spatial scale of MUs, average municipality size was large enough to contain 98% and 94% of an average female and male home range, respectively. However, even at this scale, when comparing migration distances with the diameter of the municipalities, it could potentially cover only 70% of females' and 62% of males' yearly ranges. The frequency of border crossing peaked during migration. We quantified the link between timing of autumn migration, climate, plant phenology and hunting (Ecology 2016). Severe weather has been suggested as the main trigger of autumn migration, but we found that the majority of the individuals had left the summer range before snow fall (80.3%) and frost (70.5%), and also before the peak deterioration in forage quality (71.9%). Declining temperatures were associated with a higher daily migration potential. Onset of hunting showed the largest effect on migration potential, with a marked increase the first days of hunting. Individuals still present in the summer range when snow fall, frost or peak forage deterioration occurred showed a significantly higher migration potential around these events. The onset of hunting induced an immediate switch to habitat with more concealing cover in surviving males, but not in males that were later shot (Anim Beh 2015). These results show the strong anthropogenic impact on deer behavior imposed by hunting. The overlap of timing of hunting season and migration suggests that changes in hunting season might lead to a redistribution of the harvest. We quantified the chances of being harvested in summer or winter ranges after the hunting season was advanced from 10th September to 1st September in 2012 (EJWR 2016). By moving the start of the hunting season, the proportion of animals harvested at higher elevations (summer ranges) increased by ~7%. By advancing hunting onset, hunters at higher elevations are able to harvest the animals that spend the summer in their areas before they migrate to lower elevations. This means that the hunters are able to benefit from the same animals that potentially cause grazing damage on agricultural areas during summer. These results were used as part of the scientific basis for the latest revision in hunting seasons by the Norwegian Environmental Agency. We have published a paper on habitat suitability during summer and winter under current and future climate in different landscapes for males and female red deer (PRSB 2019). With climate change, the effect of global warming on snow cover is expected to cause range expansion and enhance habitat suitability for species at their northern distribution limits. We found large increases in future winter habitat suitability, resulting in expansion of winter ranges as currently unsuitable habitat became suitable. Even moderate warming decreased snow cover substantially, with no suitability difference between warming scenarios. Winter ranges will hence not expand linearly with warming, even for species at their northern distribution limits. Although less pronounced than in winter, summer ranges also expanded and more so under severe warming. Summer habitat suitability was positively correlated with landscape topography and ranges expanded more for females than males. This highlights the complexity of predicting future habitat suitability for management of migratory species under global warming. (WP2) We have developed scripts to measure functional connectivity using GPS data. We are applying this method enabling modelling of connectivity among seasonal ranges. (WP3) We have completed an extensive online survey among landowners (Ecology & Society 2018). Invitations was then sent to 5795 members of the Norwegian Forest Owner Associations and Norwegian Farmer`s Union along the west coast. The survey suggests that landowners tend to think they know the migration pattern for red deer within their area. The majority replies that red deer enter the hunting field throughout the hunting season (57%) and these landowners were more satisfied (75%) with the longer hunting season. Larger size of management unit increased satisfaction with current management situation, and the majority of landowners welcome larger units to increase management of migratory deer.

For forvaltning: Det er oppnådd en rekke resultater fra prosjektet som vil påvirke måten vi tenker forvaltning av hjort og andre arter som beveger seg over administrative grenser. Av helt konkrete endringer, var vår forskning på DeerUnit et av grunnlagene for å flytte jakttidsstart fra 10. september til 1. september for å sikre en mer jevn fordeling av høsting mellom sommer- og vinterområder. Vår forskning har videre vist at denne effekten ble oppnådd. For forskning: Vi har levert forskning helt i den internasjonale forskningsfronten på feltet migrasjon av dyr.

A global challenge for the management of large mammals is seasonal migration. The current management units are typically too small to capture the entire migration cycle. The fall migration period coincides with the hunting season and involves extensive mo vement over management units. We aim to demarcate functional population units based on data on the full migration cycle of >300 GPS marked red deer (2005-2013), and assess how they may change under global warming. WP1 The ecology of migration: We aim to ( A) quantify the link between timing of migration, snow depth and in turn the chances for being harvested in summer or winter ranges, now and in the future. (B) We aim to quantify a landscape level functional classification of seasonal habitat suitability for red deer, and simulate if the current range contraction from summer to winter (due to snow fall) are likely to persist under global warming. (C) We aim to understand selection of winter range, and explore the feasibility of using "energy landscapes" a nd "least cost paths" as basis for quantification of the functional connectivity among seasonal ranges. WP2 Functional population units: We will scale up space use using tools to quantify connectivity among seasonal ranges and its "drainage of individuals " from a high elevation summer range to a low elevation winter range. WP3 Management implementation: We aim to validate the ongoing process of management unit demarcation based on local knowledge, suggesting more robust units. We draw on research on gover nance from the Deer Management Groups in Scotland and do research on collaboration constraints among landowners. The project is novel as we raise questions in the forefront on research of drivers of migration and how that affects distribution of the harve st. Also, a novel, generally applicable approach is our unique ideas of how to synthesize space use data using drainage models to demarcate functional population units providing managers with powerful new tools.