Hilde Karine Wam

Research Scientist

(+47) 920 10 746
hilde.wam@nibio.no

Place
Ås H8

Visiting address
Høgskoleveien 8, 1433 Ås

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Abstract

Despite decades of intense research, it remains largely unsolved which nutritional factors underpin food selection by large herbivores in the wild. We measured nutritional composition of birch foliage (Betula pubescens) available to, and used by, moose (Alces alces) in natural settings in two neighboring regions with contrasting animal body mass. This readily available food source is a staple food item in the diet of moose in the high-fitness region, but apparently underutilized by moose in the low-fitness region. Available birch foliage in the two regions had similar concentrations of macronutrients (crude protein [CP], fiber fractions, and water-soluble carbohydrates [WSC]), although a notably lower variation of WSC in the low-fitness region. For minerals, there were several area differences: available birch foliage in the low-fitness region had less Mg (depending on year) and P, but more Ca, Zn, Cu, and Mn. It also had higher concentrations of some plant secondary metabolites: chlorogenic acids, quercetins, and especially MeOH-soluble condensed tannins. Despite the area differences in available foliage, we found the same nutritional composition of birch foliage used in the two regions. Compared to available birch foliage, moose consistently used birch foliage with more CP, more structural fiber (mainly hemicellulose), less WSC, higher concentrations of several minerals (Ca, Zn, K, Mn, Cu), and lower concentrations of some secondary metabolites (most importantly, MeOH-soluble condensed tannins). Our study conceptually supports the nutrient-balancing hypothesis for a large herbivore: within a given temporal frame, moose select for plant material that matches a specific nutritional composition. As our data illustrate, different moose populations may select for the same composition even when the nutritional composition available in a given food source varies between their living areas. Such fastidiousness limits the proportion of available food that is acceptable to the animal and has bearings on our understanding and application of the concept of carrying capacity.

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Abstract

The composition of plant secondary metabolites (PSMs) extensively impacts ecosystem functioning. It is vital that we understand temporal patterns in the plants’ allocation of resources to PSMs, particularly those influenced by human activity. Existing data are insufficient in the long-term perspective of perennial plants (age or ontogeny). We analysed phenolic concentrations in foliage from birch (Betula pubescens Ehr.) considered to be undamaged and growing on 5, 10 and 15 years old clear-cuts in two boreal forest landscapes in Norway, sampled at the peak of the growing season. In sum, low molecular weight phenolic concentrations decreased with age. Apart from one apigenin glycoside, the low molecular weight phenolics co-varied similarly at all ages, suggesting a lack of temporal compound-specific prioritisation of this group. In contrast, the concentration of MeOH-soluble condensed tannins increased with age. The compositional shift fits well with several hypotheses that may provide proximate explanations for age patterns in PSM allocations, including both resource constraints and external pressures. Regardless of these explanations, our study adds an important perennial perspective (plant age) to temporal PSM patterns already well-known in boreal plant phenology (foliage age).

Abstract

Plant defence against environmental stressors often changes dramatically as plant develop. The composition of secondary compounds (PSM) in the vegetation of a landscape has extensive influence on ecosystem functioning. It is therefore crucial that we understand how various temporal factors affect plant content of PSMs, particularly those indirectly induced and controlled by human activity. One illustrative PSM group of major ecological interest is phenolics, which serve needs as diverse as herbivory defence, pathogen resistance, allelopathy or symbioses signalling, frost and drought hardiness, and photodamage protection. I will present results from our ongoing studies of defensive chemistry of European beech (Fagus sylvatica) and birch (Betula spp) across seasons and ages, and discuss the results in relation to ecological theories and functionality of plant chemical defence.

Abstract

Natural and rural land provides resources for the majority of ecosystem services we need. Typical provisioning services from these resources are timber logging, collection of berries, mushrooms and hunting. Typical regulating services are carbon storage, regulation of flooding and temperature, and typical cultural services are education, science and nature based tourism. The use of one ecosystem service always affects the other services. How can we evaluate how the various use of services affect each other? In our research group, we work innovatively with multi-criteria analyses to find ways of trading-off contradicting interests in ecosystem services. The red tread is to consider «all» sides of multiuse and thereby reduce conflicts between stakeholders. To achieve this, it is necessary to combine conventional valuation methods (market-oriented recourse-economy) and new socioecological approaches.

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Abstract

Co-existing species at the same trophic level often segregate with respect to diet, habitat use, or spatial distribution, reducing their direct competition for resources. However, temporal patterns in species-specific habitat use, for instance due to climatic variation, may affect the strength of interspecific interactions, and generate temporal variation in niche partitioning. We assessed temporal variation in habitat overlap between a wild ungulate, moose Alces alces, and two freeranging domestic ungulates, sheep Ovis aries and cattle Bos taurus, on a boreal forest range in southern Norway. We also calculated the distance between species’ realised niches, as well as the width of their realised niches to evaluate the extent of temporal niche partitioning under different diurnal weather conditions. Analyses of each habitat variable suggested complex relationships between species-specific habitat use, photoperiod, and weather, related to species-specific behaviour and activity patterns. We found shorter overall niche distance between moose and sheep, compared to moose and cattle, and shorter niche distances during day and night than during the twilight hours. The niche distance between moose and sheep was positively related to temperature during night, but negatively during day. Moreover, niche distance between moose and both sheep and cattle was negatively related to precipitation at daytime. Moose niche width was narrower in periods with short niche distance to sheep, while we did not find such pattern towards cattle. A lack of similar moose response to cattle could be attributed to lower niche overlap between moose and cattle. Our results suggest that temporal niche partitioning between moose and livestock breaks down under the weather conditions that are predicted to become more common as climate change, potentially increasing wildlife-livestock interactions in the future.

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Abstract

We are increasingly confronted with severe social and economic impacts of environmental degradation all over the world. From a valuation perspective, environmental problems and conflicts originate from trade-offs between values. The urgency and importance to integrate nature's diverse values in decisions and actions stand out more than ever. Valuation, in its broad sense of ‘assigning importance’, is inherently part of most decisions on natural resource and land use. Scholars from different traditions -while moving from heuristic interdisciplinary debate to applied transdisciplinary science- now acknowledge the need for combining multiple disciplines and methods to represent the diverse set of values of nature. This growing group of scientists and practitioners share the ambition to explore how combinations of ecological, socio-cultural and economic valuation tools can support real-life resource and land use decision-making. The current sustainability challenges and the ineffectiveness of single-value approaches to offer relief demonstrate that continuing along a single path is no option. We advocate for the adherence of a plural valuation culture and its establishment as a common practice, by contesting and complementing ineffective and discriminatory single-value approaches. In policy and decision contexts with a willingness to improve sustainability, integrated valuation approaches can be blended in existing processes, whereas in contexts of power asymmetries or environmental conflicts, integrated valuation can promote the inclusion of diverse values through action research and support the struggle for social and environmental justice. The special issue and this editorial synthesis paper bring together lessons from pioneer case studies and research papers, synthesizing main challenges and setting out priorities for the years to come for the field of integrated valuation.

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Abstract

People provide wild ungulates with large quantities of supplementary feed to improve their health and survival and reduce forest damage. Whereas supplementary feeding can positively affect the winter survival of ungulates and short-term hunting success, some of the feeds provided may actually reduce ungulate health and increase forest damage. Here, we highlight how recent advances in ungulate nutritional ecology can help explain why supplementary feeding can lead to undesirable outcomes. Using Europe’s largest cervid, the moose (Alces alces), as a model species, and Sweden, as the socio-ecological context, we explain the concept of nutritional balancing and its relevance to supplementary feeding. Nutritional balancing refers to how animals alter their food intake to achieve a specific nutritional target balance in their diet, by selecting balanced food items or by combining items with nutritional compositions that are complimentary. As the most common supplementary feeds used contain higher concentrations of non-structural carbohydrates than the ungulates’ normal winter diet, the consumption of such feeds may cause animals to increase their intake of woody browse, and thereby exacerbate forest damage. We also explain how animal health may be negatively affected by large intakes of such feed if complementary browse items are not available. We therefore suggest that the use of inappropriate feed is an additional means by which supplementary feeding may result in negative outcomes for hunters, forest owners, and wild animals.

Abstract

Finding new ways to simultaneously account for monetary and non-monetary goals in ecosystem services is needed in order to establish a new modelling framework for the facilitation of trade-offs between competing stakeholder interests. The socioecological sustainability of an ecosystem service is dependent on the consent of the people in the area of the ESS. An important reason is that a given ecosystem service may have highly different value in different stakeholder cultures. In this aspect is also the understanding of disservices and hidden services. The kind and level of conflict tend to differ with location and the operational level of decision-making. It is crucial work to identify all linked subservices and organise them into a common framework for evaluation. In our research group (MULTIESS) we try to develop multi-criteria tools to assess the implications of prioritizing different interests on ecological, sociological and economic output. Similarly, changes in the human population and environment will interact and influence on the services and their values, demanding such parameters to be evaluated for the whole range of potential scenarios. We maintain that in order to make multi-criteria analyses (MCA) successful, service outputs and externalities must and can be measured in familiar terms (e.g. money, biomass) without the use of direct or stated pricing of non-commodities such as welfare, recreation or biodiversity.