Does climate change influence the availability and quality of reindeer forage plants?

Climate change adaptation stories: Co-creating climate services with reindeer herders in Finland

Reindeer husbandry in the Arctic region is strongly affected by the local climate. Reindeer herders are used to coping with adverse weather, climate, and grazing conditions through autonomous adaptation. However, today's rapidly changing Arctic environment poses new challenges to the management of herding activities. Finding means for combining traditional and scientific knowledge without depriving any of the systems of its fundamental strengths is hence deemed necessary. In this work, we apply a transdisciplinary framework for knowledge co-production involving international researchers and reindeer herders from different cooperatives in northern Finland. Through 'climate change adaptation stories', we co-explore how climate predictions can inform herders' decision making during the herding season. Relevant decisions include the anticipation of summer harvest time, the inopportune periods of cold weather in spring, and insect harassment in summer. Despite their potential benefits for climate-sensitive decisions, climate predictions have seen limited uptake, mainly due to their probabilistic nature and lower quality compared with shorter-term weather forecasts. The analysis of two different adaptation stories shows that seasonal predictions of temperature for May and June can successfully advise about the likelihood of having an earlier than normal harvest. This information can be obtained up to three months in advance, helping herders to better arrange their time for other activities. Likewise, sub-seasonal predictions of temperature during April and May can be useful to anticipate the occurrence of backwinter episodes, which can support herders in deciding whether to feed reindeer in pens for longer, avoiding putting the survival of calves at risk. This study, which would benefit from co-evaluation in real world settings and consideration of additional adaptation stories, sets the basis for a successful co-production of climate services with Arctic reindeer herders. This research shows the potential to enhance the resilience of Polar regions, offering opportunities for adaptation while supporting the sustainability and culture of traditional practices of Arctic communities.

Nonlinear spatial and temporal decomposition provides insight for climate change effects on sub-Arctic herbivore populations

Global temperatures are increasing, affecting timing and availability of vegetation along with relationships between plants and their consumers. We examined the effect of population density, herd body condition in the previous year, elevation, plant productivity and phenology, snow, and winter onset on juvenile body mass in 63 semi-domesticated populations of Rangifer tarandus throughout Norway using spatiotemporal generalized additive models (GAMs) and varying coefficient models (VCMs). Optimal climate windows were calculated at both the regional and national level using a novel nonlinear climate window algorithm optimized for prediction. Spatial and temporal variation in effects of population and environmental predictors were considered using a model including covariates decomposed into spatial, temporal, and residual components. The performance of this decomposed model was compared to spatiotemporal GAMs and VCMs. The decomposed model provided the best fit and lowest prediction errors. A positive effect of herd body condition in the previous year explained most of the deviance in calf body mass, followed by a more complex effect of population density. A negative effect of timing of spring and positive effect of winter onset on juvenile body mass suggested that a snow free season was positive for juvenile body mass growth. Our findings suggest early spring onset and later winter permanent snow cover as reinforcers of early-life conditions which support more robust reindeer populations. Our methodological improvements for climate window analyses and effect size measures for decomposed variables provide important contributions to account for, measure, and interpret nonlinear relationships between climate and animal populations at large scales.

The Impact of Climate Change on the Food (In)security of the Siberian Indigenous Peoples in the Arctic: Environmental and Health Risks

Climate change represents a global challenge that impacts the environment, traditional lifestyle and health of the Indigenous Peoples in the Arctic zone of Western Siberia and threatens their food security. Reindeer are an important food source for this population since reindeer herding products are used as traditional nutrition and effective preventive means and remedies for adapting to the cold and geomagnetic activity in the High North. Longer off-season periods, high summer and winter temperatures, melting ice, and forest and tundra fires have a significant impact on the trampling and degradation of reindeer pastures. These effects may lead to massive reindeer losses and changes in the traditional diet of the Indigenous Peoples in the Arctic, which result in increases in the prevalence of respiratory diseases, overweight and hypertension. This study applied a multidisciplinary approach based on ecological and medical research methods with the inclusion of socioeconomic analysis. The primary sources included data on the longitudinal dynamics of air temperature as a climate change indicator and reindeer livestock populations (1936–2018), consumption of reindeer products and physiological impacts on the Yamal Indigenous population collected during expeditions to the Arctic zone of Western Siberia in 2012–2018.

Cool as a moose: How can browsing counteract climate warming effects across boreal forest ecosystems?

Herbivory has potential to modify vegetation responses to climatic changes. However, climate and herbivory also affect each other, and rarely work in isolation from other ecological factors, such as plant-plant competition. Thus, it is challenging to predict the extent to which herbivory can counteract, amplify, or interact with climate impacts on ecosystems. Here, we investigate how moose modify climatic responses of boreal trees by using experimental exclosures on two continents and modeling complex causal pathways including several climatic factors, multiple tree species, competition, tree height, time, food availability, and herbivore presence, density, and browsing intensity. We show that moose can counteract, that is, "cool down" positive temperature responses of trees, but that this effect varies between species depending on moose foraging preferences. Growth of preferred deciduous trees was strongly affected by moose, whereas growth of less preferred conifers was mostly driven by climate and tree height. In addition, moose changed temperature responses of rowan in Norway and balsam fir in Canada, by making fir more responsive to temperature but decreasing the strength of the temperature response of rowan. Snow protected trees from browsing, and therefore moose "cooling power" might increase should a warming climate result in decreased snow cover. Furthermore, we found evidence of indirect effects of moose via plant-plant competition: By constraining growth of competing trees, moose can contribute positively to the growth of other trees. Our study shows that in boreal forests, herbivory cooling power is highly context dependent, and in order to understand its potential to prevent changes induced by warming climate, species differences, snow, competition, and climate effects on browsing need to be considered.

Climate change and reindeer management in Finland: Co-analysis of practitioner knowledge and meteorological data for better adaptation

We studied interannual variability and changes over time in selected climate indices in the reindeer management area (RMA) in northern Finland. We present together the knowledge possessed by reindeer herders with information from meteorological measurements over three decades. The practitioner knowledge was gathered via a survey questionnaire addressing herder observations of long-term changes (approximately during the past 30 years) in climatic conditions and their impacts on herding during the four seasons. A set of temperature-, precipitation- and snow-related indices relevant for herding within the RMA was derived from spatially interpolated daily meteorological data (1981-2010). Climatic changes detected based on the measurement data were mainly consistent with earlier studies, and practitioner knowledge was generally in line with the meteorological data. The herders had experienced the largest number of changes during the winter, and the smallest number of changes during the summer. The herders reported various impacts of changing seasonal weather on reindeer condition and behavior, and on herding practices. Adaptation to the changing conditions requires adoption of various coping strategies by the herders in their everyday work, continuous development of professional techniques and practices, as well as support received from the governance of reindeer management. We conclude that holistic understanding of the impacts of climate change and adaptation to changes in the future requires simultaneous analyses of data from different sources, more research co-defined with local practitioners, and co-planned governance solutions. The approach presented in this work can ease the dialogue between the local practitioners, researchers and policy makers.

Response of barren-ground caribou to advancing spring phenology

Phenological shifts are occurring in many ecosystems around the world. The capacity of species to adapt to changing phenology will be critical to their success under climate change scenarios. Failure to adjust migratory and reproductive timing to keep pace with the earlier onset of spring has led to negative demographic effects for populations of species across a variety of taxa. For caribou, there have been concerns that earlier spring green-up on calving areas might not be matched by earlier migration and parturition, potentially leading to a trophic mismatch with nutritional consequences for parturient and lactating caribou cows. However, there is limited evidence supporting these concerns. Here, we investigate the response of barren-ground caribou to changing spring phenology using data from telemetry and satellite imagery. From 2004 to 2016, we found that the average start of green-up on the calving area advanced by 7.25 days, while the start of migration advanced by 13.64 days, the end of migration advanced by 6.02 days, and the date of peak calving advanced by 9.42 days. Despite the advancing onset of green-up, we found no evidence for the development of a trophic mismatch because the advancing green-up coincided with earlier migration and calving by caribou. Changing snow cover on the late winter and migratory ranges was the most supported driver of advancing migratory behavior. The ability of caribou to adjust the timing of migratory and reproductive behavior in response to changing environmental conditions demonstrates the potential resilience of the species to some aspects of climate change.

A review of climate change impacts on the ecosystem services in the Saami Homeland in Finland

The aim of this work is (i) to review the recent studies on weather and climate change in Finnish Sápmi and to present the literature review findings alongside our survey on the observations made by local reindeer herders on the same phenomena, and, further, (ii) to review the impacts of climate change on the ecosystem services (ES) in Finnish Sápmi. The focus of the study is on the impacts of climate change on those habitat, provisioning and cultural ecosystem services which are interconnected with the Saami way of life as Indigenous people and thus support the continuity of their culture. In the holistic world view of Arctic Indigenous peoples, material culture and non-material culture are not separated, and there is no boundary between nature and culture. However, cultural and spiritual meanings of ecosystems, species and landscapes are rarely taken into account in scientific research on ecosystems services. Our review indicates that mostly negative impacts of climate warming on ecosystems and traditional livelihoods are to be expected in Sápmi. The most profound negative impacts will be on palsa mire and fell ecosystems, in particular snowbeds, snow patches and mountain birch forests. Consequently, changes in ecosystems may erode cultural meanings, stories, memories and traditional knowledge attached to them and affect the nature-based traditional livelihoods. In a situation where our rapidly changing climate is affecting the foundations of the nature-based cultures, the present review can provide a knowledge base for developing adaptation actions and strategies for local communities and Indigenous peoples to cope with changes caused by climate change and other drivers.

The Holistic Effects of Climate Change on the Culture, Well-Being, and Health of the Saami, the Only Indigenous People in the European Union

PURPOSE OF REVIEW

(1) To develop a framework for understanding the holistic effects of climate change on the Saami people; (2) to summarize the scientific evidence about the primary, secondary, and tertiary effects of climate change on Saami culture and Sápmi region; and (3) to identify gaps in the knowledge of the effects of climate change on health and well-being of the Saami.

RECENT FINDINGS

The Saami health is on average similar, or slightly better compared to the health of other populations in the same area. Warming climate has already influenced Saami reindeer culture. Mental health and suicide risk partly linked to changing physical and social environments are major concerns. The lifestyle, diet, and morbidity of the Saami are changing to resemble the majority populations posing threats for the health of the Saami and making them more vulnerable to the adverse effects of climate change. Climate change is a threat for the cultural way of life of Saami. Possibilities for Saami to adapt to climate change are limited.

Experimental warming alters migratory caribou forage quality

Global declines in caribou and reindeer (Rangifer) populations have drawn attention to the myriad of stressors that these Arctic and boreal forest herbivores currently face. Arctic warming has resulted in increased tundra shrub growth and therefore Rangifer forage quantity. However, its effects on forage quality have not yet been addressed although they may be critical to Rangifer body condition and fecundity. We investigated the impact of 8 yrs of summer warming on the quality of forage available to the Bathurst caribou herd using experimental greenhouses (n = 5) located in mesic birch hummock tundra in the central Canadian Low Arctic. Leaf forage quality and digestibility characteristics associated with nutrients (nitrogen and phosphorus), phenolics, and fiber were measured on the deciduous shrub Betula glandulosa (an important Rangifer diet component) at six time points through the growing season, and on five other very common vascular plant and lichen species in late summer. Experimental warming reduced B. glandulosa leaf nitrogen concentrations by ~10% in both late June and mid-July, but not afterwards. It also reduced late summer forage quality of the graminoid Eriophorum vaginatum by increasing phenolic concentrations 38%. Warming had mixed effects on forage quality of the lichen Cetraria cucullata in that it increased nutrient concentrations and tended to decrease fiber contents, but it also increased phenolics. Altogether, these warming-induced changes in forage quality over the growing season, and response differences among species, highlight the importance of Rangifer adaptability in diet selection. Furthermore, the early season reduction in B. glandulosa nitrogen content is a particular concern given the importance of this time for calf growth. Overall, our demonstration of the potential for significant warming impacts on forage quality at critical times for these animals underscores the importance of effective Rangifer range conservation to ensure sufficient appropriate habitat to support adaptability in forage selection in a rapidly changing environment.

Observed cold season changes in a Fennoscandian fell area over the past three decades

We studied trends and variability in snow and climate characteristics in 1978-2012 in the Värriötunturit fell area, northern Finland. Cold season changes were examined using long-term observational data on snow depths, meteorological data, large-scale climate indices, and reindeer herders' experiences with difficult snow conditions. Snow depths declined, and temperatures increased significantly over the study period, with the largest changes observed in October-December and in April. Snow depths decreased particularly in forests at lower altitudes but not in treeless areas at higher altitudes. Interannual variability (but not the trends) in snow depths could be partially linked to large-scale climate indices. A majority of difficult reindeer grazing conditions were related to deep snow in the winter or spring. Our observations suggest that shortened duration of snow cover may facilitate reindeer grazing, whereas potentially more frequent formation of ice layers and mold growth on pastures in the future is disadvantageous for reindeer husbandry.

Sámi reindeer herders' perspective on herbivory of subarctic mountain birch forests by geometrid moths and reindeer: a case study from northernmost Finland

Introduction

Geometrid moths and semi-domesticated reindeer are both herbivores which feed on birch leaves in the subarctic mountain birch forests in northern Fennoscandia. The caterpillars of autumnal and winter moths have episodic outbreaks, which can occasionally lead to extensive defoliation of birch forests. Earlier studies have shown that reindeer have a negative effect on the regeneration of defoliated birches by grazing and browsing their seedlings and sprouts.

Case description

We interviewed 15 reindeer herders in the Kaldoaivi and Paistunturi herding co-operative in northernmost Finland in order to analyse their past, present and future views on the behaviour of moths and the growth of mountain birches. We investigate the behaviour of the two herbivores by combining the indigenous knowledge (IK) of Sámi herders with the results of relevant studies in biology and anthropology, applying niche construction theory (NCT) in doing so.

Discussion and evaluation

In the first stage, the niche constructors (moths, reindeer, herders, mountain birch and other organisms) are looked upon as “equal constructors” of a shared niche. As changes unfold in their niche, their role changes from that of constructor to key constructor. The role and importance of niche constructors were different when nomadic pasture rotation was used than they are today under the herding co-operative system. Niche construction faced its most radical and permanent negative changes during the border closures that took place over the latter half of the 19^th century. The large-scale nomadic life among the Sámi herders, who migrated between Finland and Norway, came to an end. This phase was followed by stationary herding, which diminished the possibilities of reindeer to look for various environmental affordances. Difficult snow conditions or birch defoliation caused by moth outbreaks made the situation worse than before. Eventually reindeer became key constructors, together with moth larvae, leading to negative ecological inheritance that forced herders to use new, adaptive herding practices.

Conclusions

Both the scientific data and the IK of herders highlight the roles of reindeer and herders as continuous key constructors of the focal niche, one which stands to be modified in more heterogenic ways than earlier due to global warming and hence will result in new ecological inheritance.

Nutritional implications of increased shrub cover for caribou (Rangifer tarandus) in the Arctic

Shrubs are increasing in the annual range of arctic caribou (Rangifer tarandus (L., 1758)), but it is unknown how much summer browse caribou could consume. We measured instantaneous intakes of resin birch (Betula glandulosa Michx.) and feltleaf willow (Salix alaxensis (Andersson) Coville) by caribou during summer. Daily intake of a formulated diet without toxins was measured during the same period to monitor appetite. Caribou appetite increased from 64.1 to 86.7 g DM·kg–0.75·day−1 as animals gained body mass from 96.8 to 113.5 kg. We estimated that caribou required 645 kJ·kg–0.75·day−1 of digestible energy to maintain body mass and 1113 kJ·kg–0.75·day−1 to gain body mass for autumn reproduction. Caribou had the same bite mass (9.7 mg·bite−1·kg–0.75) and instantaneous intake rate (0.17 g DM·min−1·kg–0.75) on both forages; however, birch contained more phenols (3.3% vs. 1.5%) and less available protein (6.2% vs. 10.2%) than willow. A 100 kg female caribou would need to consume 2.4–8.7 kg of fresh browse, requiring 3.1–8.5 h·day−1 of eating time to meet daily energy requirements. Birch is unlikely to provide enough nitrogen for maintenance of body protein. Therefore, caribou may depend on abundance and diversity of plants to offset toxin loads and low protein intake from shrubs during summer.

Climate extreme effects on the chemical composition of temperate grassland species under ambient and elevated CO2: a comparison of fructan and non-fructan accumulators

Elevated CO2 concentrations and extreme climate events, are two increasing components of the ongoing global climatic change factors, may alter plant chemical composition and thereby their economic and ecological characteristics, e.g. nutritional quality and decomposition rates. To investigate the impact of climate extremes on tissue quality, four temperate grassland species: the fructan accumulating grasses Lolium perenne, Poa pratensis, and the nitrogen (N) fixing legumes Medicago lupulina and Lotus corniculatus were subjected to water deficit at elevated temperature (+3°C), under ambient CO2 (392 ppm) and elevated CO2 (620 ppm). As a general observation, the effects of the climate extreme were larger and more ubiquitous in combination with elevated CO2. The imposed climate extreme increased non-structural carbohydrate and phenolics in all species, whereas it increased lignin in legumes and decreased tannins in grasses. However, there was no significant effect of climate extreme on structural carbohydrates, proteins, lipids and mineral contents and stoichiometric ratios. In combination with elevated CO2, climate extreme elicited larger increases in fructan and sucrose content in the grasses without affecting the total carbohydrate content, while it significantly increased total carbohydrates in legumes. The accumulation of carbohydrates in legumes was accompanied by higher activity of sucrose phosphate synthase, sucrose synthase and ADP-Glc pyrophosphorylase. In the legumes, elevated CO2 in combination with climate extreme reduced protein, phosphorus (P) and magnesium (Mg) contents and the total element:N ratio and it increased phenol, lignin, tannin, carbon (C), nitrogen (N) contents and C:N, C:P and N:P ratios. On the other hand, the tissue composition of the fructan accumulating grasses was not affected at this level, in line with recent views that fructans contribute to cellular homeostasis under stress. It is speculated that quality losses will be less prominent in grasses (fructan accumulators) than legumes under climate extreme and its combination with elevated CO2 conditions.

Climate change, land use conflicts, predation and ecological degradation as challenges for reindeer husbandry in northern Europe: what do we really know after half a century of research?

Reindeer grazing has been entitled as ecological keystone in arctic-alpine landscapes. In addition, reindeer husbandry is tightly connected to the identity of the indigenous Sámi people in northern Europe. Nowadays, reindeer husbandry is challenged in several ways, of which pasture degradation, climate change, conflicting land uses and predation are the most important. Research on reindeer-related topics has been conducted for more than half a century and this review illuminates whether or not research is capable to match these challenges. Despite its high quality, traditional reindeer-related research is functionally isolated within the various disciplines. The meshwork of ecology, socio-economy, culture and politics, however, in which reindeer husbandry is embedded by various interactions, will remain unclear and difficult to manage, if actors and relationships are kept separate. We propose some targets for new integrative research approaches that incorporate traditional knowledge and focus on the entire human-ecological system 'reindeer husbandry' to develop solutions for its challenges.

Ecological Implications of Changes in the Arctic Cryosphere

Snow, water, ice, and permafrost are showing evidence of substantial change in the Arctic, with large variations among different geographical areas. As a result of these changes, some habitats and their associated ecosystems are expanding, while others are undergoing rapid contraction. The warming of the Arctic cryosphere is limiting the range for cold-adapted biota, and less specialized taxa including invasive species from the south are likely to become increasingly common. Extreme climate events such as winter thawing are likely to become more frequent, and may accelerate shifts in community structure and processes. Many Arctic ecosystems are interdependent, and changes in the cryosphere are altering physical, biogeochemical, and biological linkages, as well as causing positive feedback effects on atmospheric warming. All of these climate-related effects are compounded by rapid socio-economic development in the North, creating additional challenges for northern communities and indigenous lifestyles that depend on Arctic ecosystem services.

Multiple Effects of Changes in Arctic Snow Cover

Snow cover plays a major role in the climate, hydrological and ecological systems of the Arctic and other regions through its influence on the surface energy balance (e.g. reflectivity), water balance (e.g. water storage and release), thermal regimes (e.g. insulation), vegetation and trace gas fluxes. Feedbacks to the climate system have global consequences. The livelihoods and well-being of Arctic residents and many services for the wider population depend on snow conditions so changes have important consequences. Already, changing snow conditions, particularly reduced summer soil moisture, winter thaw events and rain-on-snow conditions have negatively affected commercial forestry, reindeer herding, some wild animal populations and vegetation. Reductions in snow cover are also adversely impacting indigenous peoples’ access to traditional foods with negative impacts on human health and well-being. However, there are likely to be some benefits from a changing Arctic snow regime such as more even run-off from melting snow that favours hydropower operations.

Multi-decadal changes in snow characteristics in sub-Arctic Sweden

A unique long term, 49-year record (divided into three time periods 1961-1976, 1977-1992, and 1993-2009) of snow profile stratigraphy from the Swedish sub Arctic, was analyzed with a focus on changes in snow characteristics. The data set contained grain size, snow layer hardness, grain compactness, and snow layer dryness, observed every second week during the winter season. The results showed an increase in very hard snow layers, with harder snow in early winter and more moist snow during spring. There was a striking increase in the number of observations with very hard snow at ground level over time. More than twice as many occasions with hard snow at ground level were observed between 1993 and 2009 compared to previous years, which may have a significant effect on plants and animals. The changes in snow characteristics are most likely a result of the increasing temperatures during the start and the end of the snow season.