Exploring sustainability through stakeholders' perspectives and hybrid water in the Swiss alps

Can the concept of water as a socio-natural hybrid and the analysis of different users’ perceptions of water advance the study of water sustainability? In this article, I explore this question by empirically studying sustainability values and challenges, as well as distinct types of water as identified by members of five water user groups in a case study region in the Swiss Alps. Linking the concept of water as a socio-natural hybrid with the different water users’ perspectives provided valuable insights into the complex relations between material, cultural, and discursive practices. In particular, it provided a clearer picture of existing water sustainability challenges and the factors and processes that hinder more sustainable outcomes. However, by focusing on relational processes and individual stakeholder perspectives, only a limited knowledge could be created regarding a) what a more sustainable water future would look like and b) how current unsustainable practices can be effectively transformed into more sustainable ones. I conclude by arguing that the concept of water as a socio-natural hybrid provides an interesting analytical tool for investigating sustainability questions; however, if it is to contribute to water sustainability, it needs to be integrated into a broader transdisciplinary research perspective that understands science as part of a deliberative and reflective process of knowledge co-production and social learning between all actor groups involved.

Hybrid Breakdown in Cichlid Fish

Studies from a wide diversity of taxa have shown a negative relationship between genetic compatibility and the divergence time of hybridizing genomes. Theory predicts the main breakdown of fitness to happen after the F1 hybrid generation, when heterosis subsides and recessive allelic (Dobzhansky-Muller) incompatibilities are increasingly unmasked. We measured the fitness of F2 hybrids of African haplochromine cichlid fish bred from species pairs spanning several thousand to several million years divergence time. F2 hybrids consistently showed the lowest viability compared to F1 hybrids and non-hybrid crosses (crosses within the grandparental species), in agreement with hybrid breakdown. Especially the short- and long-term survival (2 weeks to 6 months) of F2 hybrids was significantly reduced. Overall, F2 hybrids showed a fitness reduction of 21% compared to F1 hybrids, and a reduction of 43% compared to the grandparental, non-hybrid crosses. We further observed a decrease of F2 hybrid viability with the genetic distance between grandparental lineages, suggesting an important role for negative epistatic interactions in cichlid fish postzygotic isolation. The estimated time window for successful production of F2 hybrids resulting from our data is consistent with the estimated divergence time between the multiple ancestral lineages that presumably hybridized in three major adaptive radiations of African cichlids.