Patterns of morphological changes and hybridization between sympatric whitefish morphs (Coregonus spp.) in a Swiss lake: a role for eutrophication?

Whitefish, genus Coregonus, show exceptional levels of phenotypic diversity with sympatric morphs occurring in numerous postglacial lakes in the northern hemisphere. Here, we studied the effects of human-induced eutrophication on sympatric whitefish morphs in the Swiss lake, Lake Thun. In particular, we addressed the questions whether eutrophication (i) induced hybridization between two ecologically divergent summer-spawning morphs through a loss of environmental heterogeneity, and (ii) induced rapid adaptive morphological changes through changes in the food web structure. Genetic analysis based on 11 microsatellite loci of 282 spawners revealed that the pelagic and the benthic morph represent highly distinct gene pools occurring at different relative proportions on all seven known spawning sites. Gill raker counts, a highly heritable trait, showed nearly discrete distributions for the two morphs. Multilocus genotypes characteristic of the pelagic morph had more gill rakers than genotypes characteristic of benthic morph. Using Bayesian methods, we found indications of recent but limited introgressive hybridization. Comparisons with historical gill raker data yielded median evolutionary rates of 0.24 haldanes and median selection intensities of 0.27 for this trait in both morphs for 1948-2004 suggesting rapid evolution through directional selection at this trait. However, phenotypic plasticity as an alternative explanation for this phenotypic change cannot be discarded. We hypothesize that both the temporal shifts in mean gill raker counts and the recent hybridization reflect responses to changes in the trophic state of the lake induced by pollution in the 1960s, which created novel selection pressures with respect to feeding niches and spawning site preferences.

A "Beyond WTO" Scenario for Swiss Agriculture: Consequences for Income Generation and the Provision of Public Goods

The conclusion of the Doha Round negotiations is likely to influence Swiss agricultural policy substantially. The same goes for a free trade agreement in agriculture and food with the European Communities. Even though neither of them will bring about duty-free and quota-free market access, or restrict domestic support measures to green box compatible support, both would represent a big step in that direction. There is no empirical evidence on the effect of such a counterfactual scenario for Swiss agriculture. We therefore use a normative mathematical programming model to illustrate possible effects for agricultural production and the corresponding agricultural income. Moreover, we discuss the results with respect to the provision of public goods under the assumption of continuing green box-compatible direct payments. The aim of our article is to bring more transparency into the discussion on the effects of freer and less distorted trade on the income generation by a multifunctional agriculture. The article will be organized as follows. In the first Section we specify the background of our study. In the second section, we focus on the problem statement and our research questions. In Section 3, we describe in detail a counterfactual scenario of “duty-free, quota-free and price support-free” agriculture from an economic as well as a legal perspective. Our methodology and the results are presented in Section 4 and 5 respectively. In Section 6, we discuss our results with respect to economic and legal aspects of multifunctional agriculture.