Habitat Loss
Other studies have suggested that the loss of habitat due to human activity and disturbance has more consequences on Rangifer populations than climate change and that these human disturbances may exacerbate the negative impact of climate change on the species. Rangifer populations are not declining synchronously around the globe due to climate change; factors such infrastructure development, forestry, and mining may play more of a role in population dynamics (Uboni, et al. 2016).
Human Infrastructure
40% of the land in Norway is used by the indigenous Sami people to herd reindeer. These herders are dependent on access to migratory routes, pastures, and calving grounds, which are already being threatened as the climate changes. In the Troms and Finnmark regions of Norway, human land use and disturbances due to urbanization, buildings, roads, energy infrastructure, and military training areas are prominent throughout the same areas used for reindeer herding. This infrastructure may result in loss of pastures and calving grounds and disrupt migratory routes and connections between pastures. Researchers looked at 91 cases in Troms from 2010-2018 regarding the effects of land use changes on reindeer herding and found that 59% of the concerns were due to green energy development (such as hydro and wind power projects), followed by tourism facilities and second homes, public roads, and power lines. In most of the cases (68%), herders were concerned about land use threats to migration routes, followed by threats to spring pastures (44%), and then calving grounds (43%) (Hausner, et al., 2019).
Hausner, et al., 2019
Hausner, et al., 2019
Other studies have reported that caribou will avoid areas with hydro, oil and gas, mining, and forestry activity by several kilometers (Festa-Bianchet, et al., 2017). In particular, reindeer abundance drastically decreases as proximity to roads and powerlines increases. However, as infrastructure continues to be developed in the Arctic, the availability of alternate habitat is declining, and at some point avoidance may no longer be possible (Vistnes & Nellemann, 2007).
Vistnes & Nellemann, 2007
In Norway, infrastructure disrupted reindeer habitat so much that a single continuous population eventually became 26 isolated subpopulations. Transportation also facilitates access to reindeer and caribou populations by hunters, poachers, and natural predators such as wolves, minimizing the extent of habitat free from these threats (Festa-Bianchet, et al., 2017).
The Arctic holds vast reserves of oil and gas, and developments to extract these resources are affecting migratory reindeer calving grounds in the Barents sea region and in southwestern Siberia. Construction of roads and pipelines in conjunction with oil and gas development is fragmenting reindeer populations, causing overgrazing of existing habitat and preventing migration to other suitable habitats. Several populations in the area have been declining, likely due to infrastructure acting as a barrier between calving and summering and wintering habitats. Additionally, oil and gas development also causes noise, pollution, and traffic, causing reindeer to avoid the habitats that would otherwise be suitable. The influx of workers into these areas also increases the risk of poaching and environmental degradation. .Furthermore, research suggests that reindeer are most vulnerable and can adapt less easily to human disturbance during late winter and the calving season (Kuemmerle, et al., 2014).
Other research has also shown that as petroleum development increased in the calving grounds of Alaskan caribou, herds abandoned these calving grounds, causing shifts in their distribution due to habitat loss. Additionally, reproductive success may be lower for caribou exposed to oil development (Visnes & Nellemann, 2007).
Kuemmerle, et al., 2014