Wohnstandortwahl der «Creative Class» in der Agglomeration Zürich

Richard Florida focuses on the selected determinants affecting the choice of residence by the creative class at the regional level. He defines these determinants with the concept “quality of place”. The question arises of whether this approach can be transferred to a subregional level. In the empirical research at the subregional level, variables are added to “quality of place” and the creative class is differentiated into sectors. In this article, Florida’s assessment is applied to the subregional level, as is usual for assessments used to explain the choice of residence location. This allows an investigation of which location factors have a deciding influence on the residence location choices of the creative class in the Zurich agglomeration and what differences, if any, can be found between the various branches. An empirical analysis of the data for the agglomeration of Zurich in 2000 supports the transferability of Florida’s approach to the subregional level. However, it is evident that the differentiation of the creative class and the addition of other determinants to “quality of place” are essential

Predictive models of distribution and abundance of a threatened mountain species show that impacts of climate change overrule those of land use change

Aim: Climate is often the sole focus of global change research in mountain ecosystems although concomitant changes in land use might represent an equally important threat. As mountain species typically depend on fine‐scale environmental characteristics, integrating land use change in predictive models is crucial to properly assess their vulnerability. Here, we present a modelling framework that aims at providing more comprehensive projections of both species’ distribution and abundance under realistic scenarios of land use and climate change, and at disentangling their relative effects. Location: Switzerland. Methods: We used the ring ouzel (Turdus torquatus), a red‐listed and declining mountain bird species, as a study model. Based on standardized monitoring data collected across the whole country, we fitted high‐resolution ensemble species distribution models to predict current occurrence probability, while spatially explicit density estimates were obtained from N‐mixture models. We then tested for the effects of realistic scenarios of land use (land abandonment versus farming intensification) and climate change on future species distribution and abundance. Results: Occurrence probability was mostly explained by climatic conditions, so that climate change was predicted to have larger impacts on distribution and abundance than any scenarios of land use change. In the mid‐term (2030–2050), predicted effects of environmental change show a high spatial heterogeneity due to regional differences in climate and dominant land use, with farming intensification identified as an important threat locally. In the long term (2080–2100), climate models forecast a marked upward range shift (up to +560 m) and further population decline (up to −35%). Main conclusions: Our innovative approach highlights the spatio‐temporal heterogeneity in the relative effects of different environmental drivers on species distribution and abundance. The proposed framework thus provides a useful tool not only for better assessing species’ vulnerability in the face of global change, but also for identifying key areas for conservation interventions at a meaningful scale

Similar successional development of functional community structure in glacier forelands despite contrasting bedrocks

Questions Primary plant succession is expected to be driven by habitat filtering and competitive exclusion. However, such findings typically come from experimental or single-site case studies. As a result, we lack field studies that investigate the functional community structures across successional series with differing site conditions. Here, we address the following question: how do plant trait patterns and functional diversity change along two chronosequences with distinct bedrocks? Methods We established two soil chronosequences with contrasting bedrock types (siliceous vs calcareous) in the Swiss Alps spanning a terrain age gradient of 13,500 years. We analysed plant ecological strategies at 40 plots per glacier foreland relating six functional traits to terrain age using RLQ analysis. We used the variation in plant ecological strategies revealed by RLQ analysis to calculate indices of functional diversity and analysed their temporal development with terrain age. Results The RLQ analysis revealed that canopy height and dispersal type were significantly associated with terrain age. In both glacier forelands, functional richness (FRic) increased with terrain age, suggesting similar development of niche differentiation along the chronosequences, irrespective of bedrock types. In addition, we observed a decrease of functional evenness (FEve) and functional divergence (FDiv) in both sites, indicating an overall trend to habitat filtering. Conclusions The results support the idea of a similar development of functional community structure along the two chronosequences, underlining the deterministic model of functional structure during succession. The functional approach of this study improves knowledge of the adaptive strategies of plant communities colonising glacier forefields and highlights the potential of comparing successional series with differing site conditions to gain a deeper understanding of successional drivers and underlying mechanisms

Landscape genetics of the Alpine newt (Mesotriton alpestris) inferred from a strip-based approach

Habitat destruction and fragmentation are known to strongly affect dispersal by altering the quality of the environment between populations. As a consequence, lower landscape connectivity is expected to enhance extinction risks through a decrease in gene flow and the resulting negative effects of genetic drift, accumulation of deleterious mutations and inbreeding depression. Such phenomena are particularly harmful for amphibian species, characterized by disjunct breeding habitats. The dispersal behaviour of amphibians being poorly understood, it is crucial to develop new tools, allowing us to determine the influence of landscape connectivity on the persistence of populations. In this study, we developed a new landscape genetics approach that aims at identifying land-uses affecting genetic differentiation, without a priori assumptions about associated ecological costs. We surveyed genetic variation at seven microsatellite loci for 19 Alpine newt (Mesotriton alpestris) populations in western Switzerland. Using strips of varying widths that define a dispersal corridor between pairs of populations, we were able to identify land-uses that act as dispersal barriers (i.e. urban areas) and corridors (i.e. forests). Our results suggest that habitat destruction and landscape fragmentation might in the near future affect common species such as M. alpestris. In addition, by identifying relevant landscape variables influencing population structure without unrealistic assumptions about dispersal, our method offers a simple and flexible tool of investigation as an alternative to least-cost models and other approaches