EBM6: Large herbivores as agents of ecosystem based management in the circumpolar Arctic) - Arctic biodiversity, Conservation of Arctic Flora and Fauna (CAFF)

EBM6: Large herbivores as agents of ecosystem based management in the circumpolar Arctic

Date: Tuesday October 9, 2018

Location: Saivo, Lappia Hall

Time: 13:00-14:30

There is an urgent need to mainstream biodiversity and ecosystem services ensuring that the recommendations and implementation of the ABA are implemented by not just government, but many organizations and peoples, and across sectors. Large herbivores, such as reindeer/caribou, bison, muskox, and horses are important drivers of diversity, structure and function in ecosystems across the circumpolar Arctic. Since the late Pleistocene, large wild herbivores have acted as agents of change between low- and high-productivity tundra and steppe-tundra ecosystems, respectively. During the late Holocene, indigenous peoples and their semi-domesticated and domesticated herds of livestock have often worked together to manipulate transitions between alternative ecosystem states to suit their collective needs. In the modern Arctic, ecosystem based management must properly account for the role of large herbivores. As Arctic ungulate populations wax and wane, it is critical to understand a range of herbivore-mediated patterns and processes. Participatory research with modern Indigenous peoples is one tool that has already demonstrated how large ungulate herds can be managed to increase or decrease e.g. woody plant diversity and ground cover. However, wild herds have also been linked to land cover changes. This session will explore the role of herbivores as agents of ecosystem based management in a series of presentations.

Chair: Bruce C. Forbes, Arctic Centre, University of Lapland

Format: Series of presentations followed by discussion

Presentations:

The role human-animal agency in ecosystem based management across the tundra zone of Northern Fennsocandia: Tim Horstkotte, Umeå University
Circumpolar arctic tundra biomass and productivity dynamics in response to projected climate change and herbivory: Howard Epstein, University of Virginia
Instability of wild reindeer migration and possibility of adaptive management by local people in Arctic Siberia: Shirow Tatsuzawa, Hokkaido University/North-Eastern Federal University
Stomping in silence: the overlooked role of ungulate trampling in shaping tundra ecosystems: Maria Väisänen, Ecology and Genetics Research Unit, University of Oulu
Rangifer management controls a climate-sensitive tundra state transition: Virve Ravolainen, Norwegian Polar Institute

Abstracts:

The role human-animal agency in ecosystem based management across the tundra zone of Northern Fennsocandia

Tim Horstkotte, Umeå University, Sweden
Jon Moen, Umeå University, Sweden
Jukka Käyhkö, Turku University, Finland
Minna Turunen, University of Lapland, Finland
Sirpa Rasmus, University of Lapland, Finland
Mia Landauer, University of Lapland, Finland
Tove Aagnes Utsi, Arctic University of Norway, Norway
Bruce Forbes, University of Lapland, Finland

Many primary livelihoods in Arctic and sub-Arctic regions experience accelerating effects of environmental change. The often close connection between indigenous peoples and their respective territories allows them to make detailed observations of how these changes transform the landscapes where they practice their daily activities. Here, we report Sami reindeer herders’ observations based on their long-term inhabitance and use of contrasting pastoral landscapes in northern Fennoscandia. In particular, we focus on the capacity for various herd management regimes to prevent a potential transformation of open tundra vegetation to shrubland or woodland. Sami herders did not confirm a substantial, rapid, or large-scale transformation of treeless tundra areas into shrub- and/or woodlands. However, where they observe encroachment of open tundra landscapes, a range of factors was deemed responsible. These included abiotic conditions, anthropogenic influences, and the direct and indirect effects of reindeer. The advance of the mountain birch tree line was in some cases associated with reduced or discontinued grazing and fire- wood cutting, depending on the seasonal significance of these particular areas. Where the tree line has risen in elevation and/or latitude, herding practices have by necessity adapted to these changes. Exploiting the capacity of reindeer impacts on vegetation as a conservation tool offers time-tested adaptive strategies of ecosystem management to counteract a potential encroachment of the tundra by woody plants. How- ever, novel solutions in environmental governance involve difficult trade-offs for ecologically sustainable, economically viable, and socially desirable management strategies.

Circumpolar arctic tundra biomass and productivity dynamics in response to projected climate change and herbivory

Howard Epstein, University of Virginia; Donald Walker, University of Alaska, Fairbanks, USA

Satellite remote sensing data have indicated a general ‘greening’ trend in the arctic tundra biome. However, the observed changes based on remote sensing are the result of multiple environmental drivers, and the effects of individual controls such as warming, herbivory, and other disturbances on changes in vegetation biomass, community structure, and ecosystem function remain unclear. We apply ArcVeg, an arctic tundra vegetation dynamics model, to estimate potential changes in vegetation biomass and net primary production (NPP) at the plant community and functional type levels. ArcVeg is driven by soil nitrogen output from the Terrestrial Ecosystem Model, existing densities of Rangifer populations, and projected summer temperature changes by the NCAR CCSM 4.0 general circulation model across the Arctic. We quantified the changes in aboveground biomass and NPP resulting from (i) observed herbivory only; (ii) projected climate change only; and (iii) coupled effects of projected climate change and herbivory. We evaluated model outputs of the absolute and relative differences in biomass and NPP by country, bioclimate subzone, and floristic province. Estimated potential biomass increases resulting from temperature increase only are approximately 5% greater than the biomass modeled due to coupled warming and herbivory. Such potential increases are greater in areas currently occupied by large or dense Rangi- fer herds such as the Nenets-occupied regions in Russia (27% greater vegetation increase without herbivores). In addition, herbivory modulates shifts in plant community structure caused by warming. Plant functional types such as shrubs and mosses were affected to a greater degree than other functional types by either warming or herbivory or coupled effects of the two.

Instability of wild reindeer migration and possibility of adaptive management by local people in Arctic Siberia

S. Tatsuzawa1, 3,
I. Okhlopkov 2,
E. Nikolaev3,
R. Kirillin2,
E. Kirillin2,
M. Nicholai2
N. Solomonov 2, 3

1 Graduate School of Letters/Arctic Research Center, Hokkaido University, Japan 2 Institute for Biological Problems of Cryolithozone, SB RAS, Russia 3 North-Eastern Federal University, Russia

In East Siberia, the distribution and composition of birds and mammals have been changed rapidly in the last 30 years under the global warming condition. In particular, the change and de-stabilization of migration route of the wild tundra reindeer Rangifer tarandus is a serious problem for local residents, especially indigenous/small numbered peoples to maintain their traditional hunting livelihood. Therefore, to know current distribution and migration trends of wild tundra reindeer in the western part of the republic of Sakha (Yakutia), we have tracked about 30 animals from 2009 by using of satellite radio transmitters (Argos-Argos, GPS-Argos). Results are as follows; 1) Their migration routes have been shifted to the south, and utilization of tundra area was decreasing compared with 30 years ago, 2) Taymyr and Lena-Olenek populations have been mixed by their migration route changes, 3) Their wintering range are tends to concentrate on upper stream area of Olenek river, although they are dispersed in summer, and 4) Their migration ranges are restricted to “reindeer lichen habitat”, and disturbed by large scale developments in their wintering area. Based on our tracking data and ground observation data by local people, we proposed to the local government to set up an “adaptive” protected area for wild reindeer, and it has been realized and is now in evaluation. Although this protected area seems to be effective for both reindeer population and the indigenous people hunting, social/ecological conflicts with local residents/ecosystem are concerned. This provides a case study on how the changes in behavior and distribution of wild tundra reindeer by global warming affect local ecosystems and indigenous/local communities.

Stomping in silence: the overlooked role of ungulate trampling in shaping tundra ecosystems

Maria Väisänen, Ecology and Genetics Research Unit, University of Oulu
Henni Ylänne, Centre for Environmental and Climate Research, Lund University

The circumpolar tundra is widely grazed by ungulates, such as reindeer, muskox, sheep and moose. They influence their surrounding environment through plant consumption, excretion of urine and feces and trampling. The existing theoretical frameworks have centered on the roles of consumption and excretion and, accordingly, these mechanisms have been considered as the main drivers of ungulate-induced ecosystem shifts whereas the role of ungulate trampling remains largely unknown. However, the effect of trampling was recently suggested to become more important as the body-weight of the plant-feeding animal increases. We argue that trampling may be the most dominant ungulate mechanism, since ungulates are large-sized and trampling always coincides with ungulate presence and may exert impacts on the environment either alone or in combination with consumption and excretion. Separating the effect of trampling from the other mechanisms is challenging and thus, experimental evidence of trampling effects is largely missing Conceptual frameworks are required to facilitate research. We used expert knowledge elicitation and reviewed literature to develop conceptual models about ungulate trampling. Firstly, we propose a concept that integrates the effects of ungulate body-weight, population density and behavior. This concept, effective trampling intensity, can be used to describe and standardize trampling effects between sites. Secondly, we propose a pathway of trampling-induced changes in soil physicochemical, structural and biotic properties and their ultimate effects on key ecosystem processes, such as greenhouse gas release. This pathway gives directions on what to measure from soil and how to link the findings with other soil attributes and even ecosystem-level processes. Finally, we discuss the roles of seasonality and varying effective trampling intensity in modulating the trampling impacts on soil and ponder the role of trampling legacy in shaping tundra ecosystems now and in the future.

Rangifer management controls a climate-sensitive tundra state transition

Kari Anne Bråthen, UiT- The Arctic University of Norway
Virve Ravolainen, Norwegian Polar Institute

We present results from a regional scale study that demonstrates the impact of a managed ungulate on a climate-sensitive tundra state transition. The focal tundra state, shrubland, is of high importance for biodiversity of plants, insects and birds and reported to be rapidly changing due to climate warming. Rangifer (caribou/reindeer) management has been suggested to mitigate the temperature-driven transition of arctic tundra into a shrubland state, yet how is uncertain. We used a large-scale quasi-experimental study design that included real management units that spanned a wide range of Rangifer population densities and summer temperatures in order to assess the relative importance of these two driving variables. Ground-surveys provided data on density and height of the small shrub life stages, while the distributional limit (shrubline) of established shrublands was derived from aerial photographs. Where Rangifer densities were above a threshold of approximately 5 animals km-2 we found, in accordance with the expectation of a “browse trap”, that the small life stages of shrubs in grasslands were at low height and low abundance. At Rangifer densities below this threshold the small life stages of shrubs were taller and more abundant indicating Rangifer were no longer in control of the grassland state. For the established shrubland state, we found that the shrubline was at a 100 m lower elevation in the management units where Rangifer have been browsing in summer as opposed to the migratory ranges with no browsing in summer. In both seasonal ranges the shrubline increased 100 m per 1°C increment in temperature. Our study supports the proposal that Rangifer management within a sustainable range of animal densities can mitigate the much-focused transition from grassland to shrubland in a warming arctic.