Group Wedekind
Evolutionary Biology and Ecology
Evolutionary Conservation Biology

In general, any captive or supportive breeding should minimize the variance in reproductive success that is not linked to viability traits. However, minimizing reproductive skew might not be the best conservation strategy if potential mates differ in their heritable viabilty. If a reproductive skew can be positively linked to heritable viability, there might be a way to optimize this skew with respect to the long-term survival prospects of a population. We are working on the optimal compromise between promoting genetic variation versus promoting heritable viability in small populations.

Life-history theory predicts that parents weigh their investment in each individual offspring according to the fitness return of the offspring. Parents may therefore alter their investment in particular breeding attempts according to the likelihood of its success and to the perceived attractiveness of their mates. This kind of trade-off calculations may not always work for small populations in their changed (and possibly protected) environment. We develop management strategies that make optimal use of phenotypic plasticity in life-history traits.

Fishing and hunting probably never means taking a random sample of a population. By fishing and hunting, humans are likely to select against certain traits and promote others. We study the evolutionary consequence of various fishing and hunting rules.

Manipulating population sex ratio is often possible, either through non-invasive methods like changing sex-determining ecological or social factors, or through more invasive methods such as hormone treatment of embryos. There are
a number of scenarios in which manipulations of sex ratios may, over a certain time span, be a desired option to promote population growth. The most obvious ones are:
(i) Very small or rapidly declining population sizes call for emergency actions like, for example, captive breeding programs. The increase of population size to above critical levels is one of the first aims of these programs. When population growth is restricted by the availability of oocytes rather than by the availability of sperm, manipulating sex ratio towards more females might be desirable under some circumstances.
(ii) The sex ratio in small populations is sometimes skewed for a variety of reasons. Manipulating the sex ratio of the coming generations towards less skewed ratios or towards different types of skews might be one of the aims of conservation efforts, especially if the present skew is male biased.

Organic pollution (here defined as increase of dissolved organic nutrients) enhances the mortality of many water-living organisms. We experimentally study various pathways that may link organic pollution, pathogen growth, and the viabilty of fish eggs.

Chemical substances that could become exotoxicologically relevant have to pass a number of tests before being marketed. In Switzerland and many other countries, these tests are largely following the OECD guidelines (www.oecd.org). We are currently describing problems with some of these guidelines. We are also testing alternative methods that have the potential to solve these problems and even reduce the evaluation costs for the producer and importer of the substances.

Game theory can to a large extent explain how cooperation evolves in conflict situations. Many conservation problems are the consequence of conflicts, e.g. of cooperation problems between different stakeholders. We study whether and where game theory can help solving conservation problems.