Trend sports threaten wildlife

Stress from constant disturbances consumes energy

Black grouse © University of Bern
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A new study shows that in the Alps booming trend sports such as variant skiing and snowboarding, ski touring and snowshoeing endanger the life of the wild animals and push back this back.Ursache is above all the great loss of energy due to constant disturbances.

The alpine ecosystems have been radically changed by the booming winter sports in recent decades. Wide, formerly quiet winter areas are now visited by tens of thousands of tourists between December and March. This poses problems for the native fauna: it lacks the ability to adapt to new changes, as human disturbances are on an unprecedented scale.

The wild animals in the Alps had to develop special adaptations to survive in the harsh mountain winter. The more difficult the winter nutritional conditions are, the more energy they have to save. An external disturbance can destabilize this subtle physiological balance and lead to energy loss. If it exceeds a certain threshold, it can no longer be compensated and then affects the state of health and even the survival of the animals.

Stress hormone as a marker

A Swiss and Austrian research group headed by Professor Raphaël Arlettaz from the University of Bern has now studied the physiological reactions of a characteristic and endangered species of the Alps. The choice fell on the black grouse because it inhabits exactly the areas most heavily used by skiing, namely the transition zone from the coniferous forest to the alpine pastures near the upper timberline.

The researchers developed a so-called non-invasive method, which allows to measure the stress level of the birds, without having to catch them - because the catch itself would be a disturbance caused by the researchers for the bird. With this method, degradation products of corticosterone, the most important stress hormone in birds, can be quantified, which come from the fecal samples of the birds. display

Black grouse in the stress test

In winter, black grouses spend more than 20 hours resting in snow caves per day. Thus, they benefit both from the thermal insulation of the snow, as well as the protection against predators. The feces of the black grouse pile up at the bottom of these igloos. The scientists collected feces in the old snow caves and then analyzed them for breakdown products of stress hormones. In a first step, they used to soak in the chronic level of stress, the cumulative effect of a prolonged stress that is increasingly affecting birds in different areas.

They compared "natural" habitats (no or very weak human disorder); Areas with moderate disturbances (areas reserved for ski touring and snowshoeing); and finally by various winter sports activities severely disturbed zones (near ski resorts).

The results clearly show about 20 percent higher stress in moderately and severely disturbed areas compared to the situation in undisturbed areas. The values ​​from the moderately and strongly disturbed zones were the same. These results show that even moderate disturbances, caused by ski tours or variation skiers, prove to be problematic for the birds.

As a result, the researchers conducted outbreaks of wild birds outdoors in the wild. To do this, they carried telemetry transmitters, which allowed the animals to be individually recognized and their respective locations located to measure the immediate physiological and hormonal stress response of birds to a stress event. The researchers approached the igloos on touring skis, whereupon the birds flew open. From the abandoned igloos was then collected the feces. Again, the results were unequivocal: the bird's stress increases by 60 percent from one day without any disturbance (control) to the next day with experimental disturbances.

Acute hazard detected

With these results, the physiological effects of winter sport on wild animals could be quantified for the first time. It is now clear that their stress level is significantly increased. Continuing work will demonstrate the exact impact of human disorders on the health and survival of birds. However, it already suggests that the stress caused by man has great effects: in combination with prolonged phases, which the birds have to spend outside their igloos and give them an increased R This could explain why the existence of black grouse is 30 to 50 percent less dense in the areas heavily affected by winter sports activities.

Arlettaz concludes: "Only a policy of creating suitable winter rest areas will allow the alpine fauna to persist in the long term, despite the growing pressure of human disturbances in this sensitive ecosystem." His research group will now develop spatial models that would allow cartographic separation of priority areas for such quiet zones. Of these, the entire wild fauna - even less endangered species than the black grouse - should profit.

(University of Bern, 07.03.2007 - NPO)