Project BEAR HEALTH 2016/23/P/NZ9/03951/3: “Wildlife health in human-shaped environment: integrating multiple indicators to assess the status of brown bear populations”
Project is financed by the National Science Centre, within the “POLONEZ 3” progamme, realised by the Institute of Nature Conservation PAS in Krakow.
Project duration: 01.12.2018 to 30.11.2020.
As all wildlife, or even more, the brown bears are affected by the loss of living space and the changes in the remaining patches of habitat. That has led to the extinction of bears in most parts of Western Europe. Poland, Croatia and Sweden still have bears in parts of the countries. They belong to the Carpathian, Dinaric-Pindos and Scandinavian populations, respectively. However, bears have still to cope with an environment that is being changed by human activities. Some examples are the development of buildings and transport infrastructure into bear habitat, a growing number of tourists in natural areas, the increased supply of human foods that are accessible to bears, such as garbage, corn fields or food provided in the forest to feed wildlife, hunting of bears or higher levels of pollution. All these activities have an effect on bears and their health. In this study, we want to check how the “humanization” of the environment affects brown bear health. For that, we will measure several parameters indicative of health condition in the hairs, scats, bones and tissues of brown bears from Poland, Croatia and Sweden. These samples will be obtained from data banks and scientific collections in the research institutions of the three countries collaborating in this project. They will be complemented with samples collected in the field in a non-invasive way.
(a) Short – and long-term stress
The goal of this module is to investigate whether and how human activities affect stress levels in different time scales in the studied individuals and populations, as well as the potential consequences for their health and conservation status. It will be done by assessment of cortisol (glucocorticoid) concentrations in hair samples using enzyme immune assay techniques.
(b) Nutritional status
Here we aim to gain knowledge on the foods consumed by bear populations on a local scale, and that will provide important insight into their condition, level of habituation or food-conditioning and habitat selection, among others. Evaluation of the assimilated diet will be done via stable isotope analysis of brown bear tissues (hairs, bones) and bear foods, and fatty acids analysis of blood.
(c) Immune response
Here we plan to investigate whether a gradient of human disturbance results in modifications of the immune responses, and how those are related to other measured indicators. We will be measuring concentrations of immunoglobulins and antibodies to biological pathogens via immune enzyme assays and immunoblots.
(d) Pathogen and toxicant exposure
Within this module parasites will be searched for macroscopically outside and inside the bears’ body. Bears found dead and hunted will be carefully examined, by inspection of various organs, and analysis of collected faeces. Environmental parasite burden will be evaluated in soil samples collected at feeding sites and control sites to assess their role in pathogen load and transmission. For bacteria and viruses, fresh samples from organs, faeces and swabs of body openings will be taken, and standard microbiological procedures will be applied. The fungi will be searched in the swabs of the skin and body openings. Indirect proof of bear exposure to living pathogens will be done by testing for antibodies in the serum. The presence of heavy metals, radionuclides and pesticides will be tested in bear organs from dead animals and in hairs collected non-invasively. The obtained values will be evaluated according to reference values for human safety.
(e) Integration of indicators and development of a health index
The data obtained will be compiled into a single database for further statistical analyses. We will use different statistical tools, to infer relationships among the health indicators, to disentangle the effects of human influences on the indicators measured, as well as to test differences among populations. We will examine in detail the mutual dependency and feedbacks among the indicators, e.g. associations of short- and long-term stress, parasitic load, diet features and immune response. We will attempt to provide threshold values for the indicators, and these findings will be integrated into a health index. This index will reflect the population status and will be tested in a sample of captive bears under a range of conditions. The integrative approach will reveal the inter-dependency of investigated parameters and provide an in-depth comparison of bear populations in the Carpathians, Dinarids and Scandinavia.
This study will pave the way for additional standards in brown bear and other wildlife research. When tracking stress, food assimilation and flow of pathogens become the routine procedure, risky changes in the environment could be detected early enough to apply proper conservation measures. Science will have a powerful and standardized tool to monitor ecosystem stability. The civilization already made a decision that the loss of biodiversity has to be stopped. The results of this research will represent a contribution in that direction and may reveal brown bears as sentinels of detrimental changes in the environment.