Past and future ecosystem change in Torngat Mountains National Park
(Tongait KakKasuangita SilakKijapvinga), northern Nunatsiavut, Labrador
By Andrew Trant, Emma Davis, Luise Hermanutz, Alain Cuerrier, Rodd Laing, Tom Knight, Holly Lightfoot, Laura Siegwart, Collier, Darroch Whitaker, and Robert Way
River flowing onto Southwest Arm, Saglek Fiord, near the southern boundary of Torngat Mountains National Park. The valley bottom is characterized by alluvial deposits and tall willow and alder thickets interspersed with areas of low shrub and wet areas from old, orphaned river channels, and fringed with talus overgrown with shrub thickets on the valley walls. Photo: Darroch Whitaker, Parks Canada
Tongarsoak is a powerful spirit that guards the Torngat Mountains of northern Nunatsiavut, Labrador. The soaring peaks are the highest mountains in North America east of the Rockies (1,600 metres above sea level), and have been the homeland of the Nunatsiavut and Nunavik Inuit for millennia. The rocks are ancient – just shy of four billion years old[1] – but recent climate change is transforming the landscape. The Inuit gifted the land to the people of Canada in 2005, establishing Torngat Mountains National Park (Tongait KakKasuangita SilakKijapvinga). Together with the Akami-UapishkU-KakKasuak-Mealy Mountains National Park Reserve, established in 2017, the two largest mountain massifs in Labrador have been protected and are managed cooperatively.
Figure 1. At Ramah Bay, in Torngat Mountains National Park, a site (A) has been rephotographed between 1991 and 2018, and compared with (B) changes in land cover at a regional scale over a similar time period. The blue circle represents the location of the site in (A). White areas on the map are water, snow, or missing data due to cloud cover. Maps are the output of a land cover change model developed for the Park using Landsat surface reflectance imagery (U.S. Geological Survey) and a high-resolution ecotype map (Ponomarenko and Quirouette 2014).
The low Arctic environment of the Torngat Mountains hosts a blend of boreal and arctic wildlife, harbouring iconic animals such as polar bear (Ursus maritimus) and the distinct population of Torngat Mountains caribou (Rangifer tarandus). In the southern extent of the Torngat Mountains, lush shrubs grow in valley bottoms, grading to lichen fellfield on the peaks. Vegetation in the north is sparse and is dominated by lichen and much more open tundra. The Torngat Mountains characterize elements of coastal arctic mountain ranges, including abundant seasonal sea ice, perennial snow patches, glaciers and widespread permafrost.[2] In the last ten years, however, extensive environmental change has been documented through scientific studies and the sharing of Inuit Knowledge.
Northern Nunatsiavut, Labrador, has undergone a significant amount of warming since the early 1980s, with this trend being more pronounced in the fall and winter.[3] In a region where August is the warmest month – an average of 8°C and the coldest month (February) at -25°C (1989- 2018)[4] – cold temperatures control what occurs above and below ground. Much of the Torngat Mountains are also strongly influenced by their proximity to the North Atlantic Ocean. Since the mid-1980s, Nunatsiavut has experienced a decline in summer sea ice at a rate of thirty percent per decade,[5] which, due to connections with regional climate feedbacks, has been demonstrated to influence tundra plant productivity.[6] The close proximity to the coast results in abundant year-round precipitation.
Recently observed changes to glacier area (nine percent decline from 2005-2008) further highlight the sensitivity of the Torngat Mountains to regional climate change.[7] The sensitivity of the region’s permafrost, by contrast, is more challenging to assess owing to a lack of long-term monitoring and field data. Coarse modelling suggests that regional permafrost changes are ongoing[8] though complicated by linkages between local geomorphology, tundra vegetation and permafrost thaw.[9]
Figure 2. Map of Torngat Mountains National Park showing the distribution of shrubs in 2014 (A) and the probability of shrub expansion by 2039/43 (B). Areas with the highest probability of change are located in valley bottoms with this pattern being most pronounced in the south of the Park. Maps were generated from a predictive model of vegetation change developed for the Park from Landsat surface reflectance imagery (U.S. Geological Survey) and a high-resolution ecotype raster (Ponomorenko and Quirouette 2014).
Across the Arctic, there is widespread evidence that tundra vegetation is changing with shrubs growing taller, becoming more dense, and establishing in areas where they were previously absent. This change, referred to as shrubification[10] has been documented across Nunatsiavut through Inuit Knowledge,[11] remote-sensed greening,[12] and by comparing remote-sensed greening to high resolution plot data.[13] In the Torngat Mountains, long-term observations from Ramah Bay, a culturally significant site and source of Ramah chert, provides compelling photographic evidence of shrubification over twenty-seven years (Figure 1A). This is further contextualized at a regional scale by comparing changes in remote-sensed land cover data over comparable time steps (Figure 1B). By the 2039/43 time period, shrub dominated habitat in Torngat Mountains National Park is predicted to increase by approximately fifty percent beyond its 2014 extent (Figure 2).
Two glacier carved valleys converge and then turn south towards North Arm, Saglek Fiord. The river supports a productive run of Arctic Char (Salvelinus alpinus) and there are hundreds of archaeological features along the valley. Photo: Darroch Whitaker, Parks Canada
These changes, most evident in valley bottoms and riparian areas, present significant challenges for Inuit and a variety of culturally important wildlife species. Travel in both the summer and winter becomes more difficult. In the winter, a shrubbier landscape presents more hazards for snowmobiles and also traps more snow,[14] resulting in an uneven distribution of snow across the landscape, especially in riparian areas. Berry availability may also decline as increased shade, due to additional and larger shrubs, has been associated with a decrease in berry productivity just south of Torngat Mountains National Park near Nain, Nunatsiavut.[15] Greater shrub canopy cover also increases the moisture maintained under the shrub canopy and has been shown in nearby Nunavik to negatively affect lichen abundance and diversity,[16] an important winter forage of the culturally important and endangered Torngat Mountain caribou population.[17]
Looking ahead, the Torngat Mountains are expected to undergo further temperature warming and increased precipitation by the end of the century,[18] and like many high-latitude mountain regions, this will be the major driver of environmental change in the Torngat Mountains. Continued research partnerships with Inuit will help to understand the impacts of this change and this knowledge will ultimately help to build resilient communities.
Two glacier-fed tributaries flow from the Selamiut Range of the Torngat Mountains into the Palmer River, which flows north and empties into Nachvak Fiord. Scree and talus fans along the valley walls connect the rocky highlands to the vegetated valley bottoms. Photo: Darroch Whitaker, Parks Canada
AUTHORS
Andrew Trant is an Associate Professor and ecologist in the School of Environment, Resources and Sustainability at the University of Waterloo.
Emma Davis is a postdoctoral fellow at the University of Waterloo’s school of environment, resources and sustainability.
Luise Hermanutz is an Honorary Research Professor in the Department of Biology, Memorial University of Newfoundland and Labrador.
Alain Cuerrier is an Adjunct Professor, Institut de Recherche en Biologie Végétale, Université de Montréal.
Rodd Laing is the Director of Environment with the Nunatsiavut Government Tom Knight is a Project Manager.
Holly Lightfoot is a Resource Management Officer.
Darroch Whitaker is Ecologist Team Leader with the Parks Canada, Western Newfoundland and Labrador Field Unit.
Robert Way is an Assistant Professor and physical geographer at the Northern Environmental Geoscience Laboratory, Department of Geography and Planning, Queen’s University.
References
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[2] Way, R.G., Bell, T., and Barrand, N.E. 2014. An inventory and topographic analysis of glaciers in the Torngat Mountains, northern Labrador, Canada. Journal of Glaciology, 60: 945–956. doi:10.3189/2014JoG13J195; Way, R.G., Wang, Y., Bevington, A.R., Bonnaventure, P.P., Burton, J., Davis, E., Garibaldi, M.C., Lapalme, C.M., Tutton, R. and Wehbe, M.A.E. 2021. Consensusbased rock glacier inventorying in the Torngat Mountains National Park, northern Nunatsiavut, Labrador. Proceedings of the 2021 Regional Conference on Permafrost & 19th International Conference on Cold Regions Engineering. Boulder, Colorado, USA.
[3] Rapinski, M., Payette, F., Sonnentag, O., Herrmann, T. M., Royer, M. J. S., Cuerrier, A., Siegwart Collier, L., Hermanutz, L., Guanish, G., Elders of Kawawachikamach, Elders of Kangiqsualujjuuaq, and Elders of Nain. 2018. Listening to Inuit and Naskapi peoples in the eastern Canadian Subarctic: a quantitative comparison of local observations with gridded climate data. Regional Environmental Change, 18(1), 189-203; Davis, E., Trant, A., Hermanutz, L., Way, R.G., Lewkowicz, A.G., Siegwart Collier, L., Cuerrier, A., and Whitaker, D. 2020. Plant–Environment Interactions in the Low Arctic Torngat Mountains of Labrador. Ecosystems, doi:10.1007/s10021-020-00577-6.
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[5] Barrette, C., Brown, R., Way, R.G., Mailhot, A., Diaconescu, E.P., Grenier, P., Chaumont, D., Dumont, D., Sévigny, C., Howell, S., and Senneville, S. 2020. Nunavik and Nunatsiavut regional climate information update, second iteration. In Nunavik and Nunatsiavut: From science to policy. An Integrated Regional Impact Study (IRIS) of climate change and modernization. Edited by P. Ropars, M. Lemay, and M. Allard. ArcticNet, Québec City, Canada. pp. 1–66.
[6] Bhatt, U.S., Walker, D.A., Raynolds, M.K., Comiso, J.C., Epstein, H.E., Jia G., Gens R., Pinzon, J.E., Tucker, C.J., Tweedie C.E., and Webber, P.J. 2010. Circumpolar Arctic tundra vegetation change Is linked to sea ice decline. Earth Interactions, 14(8): 1-20; Buchwal, A., Sullivan, P.F., Macias-Fauria, M., Post, E., Myers- Smith, I.H., Stroeve, J.C., Blok, D.,Tape, K.D., Forbes, B.C., Ropars, P. and Lévesque, E. 2020. Divergence of Arctic shrub growth associated with sea ice decline. Proceedings of the National Academy of Sciences, 117(52): 33334-33344.
[7] Barrand, N.E., Way, R.G., Bell, T., and Sharp, M.J. 2017. Recent changes in area and thickness of Torngat Mountain glaciers (northern Labrador, Canada). The Cryosphere, 11: 157–168. doi:10.5194/tc-11-157-2017; Barrette et al. 2020.
[8] Zhang, Y., Chen, W., and Riseborough, D.W. 2006. Temporal and spatial changes of permafrost in Canada since the end of the Little Ice Age. Journal of Geophysical Research, 111. doi:10.1029/2006JD007284; Way, R. G. & Lewkowicz, A. G. 2016. Modelling the spatial distribution of permafrost in Labrador– Ungava using the temperature at the top of permafrost. Canadian Journal of Earth Sciences, 53, 1010-1028.
[9] Davis, E., Trant, A., Hermanutz, L., Way, R.G., Lewkowicz, A.G., Siegwart Collier, L., Cuerrier, A., and Whitaker, D. 2020. Plant– Environment Interactions in the Low Arctic Torngat Mountains of Labrador. Ecosystems, doi:10.1007/s10021-020-00577-6.
[10] See Myers-Smith, I.H., B.C. Forbes, M. Wilmking, M. Hallinger, T. Lantz, D. Blok, K.D. Tape, M. Macias Fauria, U. Saas-Klaassen, E. Levesque, S. Boudreau, P. Ropars, L. Hermantz, A. Trant, L. Siegwart Collier, S. Weijers, J. Rozema, S.A. Raback, N. Martin Schmidt, G. Schaepman-Strub, S. Wipf, C. Rixen, C. Menard, S. Venn, S. Goetz, S. Andreu-Hayles, S. Elmendorf, H.E. Epstein, J. Welker, P. Grogan & D.S. Hik. 2011. Shrub expansion in tundra ecosystems: dynamics, impacts and research priorities. Environmental Research Letters 6: [045509 – 15 pp] - doi:10.1088/1748-9326/6/4/045509
[11] Parks Canada. 2008. State of the park report, Torngat Mountains National Park of Canada. Unpublished report. Rocky Harbour, Newfoundland and Labrador, Canada: Parks Canada; Siegwart Collier, L. 2020. Climate change impacts on berry shrub performance in treeline and tundra ecosystems. PhD thesis, Department of Biology, Memorial University of Newfoundland.
[12] Fraser, R.H., Olthof, I., Carrière, M., Deschamps, A., & Pouliot, D. 2011. Detecting long-term changes to vegetation in northern Canada using the Landsat satellite image archive. Environmental Research Letters 6(4): 045502.
[13] Davis, E., Trant, A., Hermanutz, L., Way, R.G., Lewkowicz, A.G., Siegwart Collier, L., Cuerrier, A., and Whitaker, D. 2020. Plant– Environment Interactions in the Low Arctic Torngat Mountains of Labrador. Ecosystems, doi:10.1007/s10021-020-00577-6; Larking T., Davis E., Way R., Hermanutz L., and Trant A.J. 2021. Recent greening driven by species specific shrub growth characteristics in Nunatsiavut, Labrador, Canada. Arctic Science. Accepted.
[14] Sturm, M., Holmgren, J., McFadden, J.P., Liston, G.E., Chapin III, F. S., & Racine, C.H. 2001.Snow–shrub interactions in Arctic tundra: a hypothesis with climatic implications. Journal of Climate, 14(3), 336-344.
[15] Boulanger-Lapointe, N., Gérin-Lajoie, J., Siegwart Collier, L., Desrosiers, S., Spiech, C., Henry, G.H., Hermanutz, L, Lévesque, E. & Cuerrier, A. 2019. Berry plants and berry picking in Inuit Nunangat: Traditions in a changing socio-ecological landscape. Human Ecology, 47(1), 81-93; Boulanger-Lapointe, N., Henry, G. H., Lévesque, E., Cuerrier, A., Desrosiers, S., Gérin-Lajoie, J., ... & Siegwart Collier, L. S. 2020. Climate and environmental drivers of berry productivity from the forest–tundra ecotone to the high Arctic in Canada. Arctic Science, 6(4), 529-544.
[16] Chagnon C. and Boudreau S. 2019. Shrub canopy induces a decline in lichen abundance and diversity in Nunavik (Québec, Canada). Arctic, Antarctic, and Alpine Research 51:521–532.
[17] COSEWIC. 2017. COSEWIC assessment and status report on the caribou Rangifer tarandus, eastern migratory population and Torngat Mountains population, in Canada. Committee on the Status of Endangered Wildlife in Canada. Ottawa.
[18] Barrette et al. 2020.