Abstract
Switzerland's biodiversity is systematically surveyed by an array of programs, each designed to cover distinct facets of biodiversity across spatial scales as well as policy evaluation needs.
Although each initiative has discrete aims, collectively, they form a complementary set of programs that collect data, when analyzed in combination, offer significant added value to document and understand biodiversity trends. One of these programs is the Swiss Biodiversity Monitoring (BDM) which focuses on the collection of data on common and widespread species, thereby illuminating developments in the normal landscapes outside protected areas. Special attention is paid to vascular plants and butterflies, which are recorded on the same study plots. Since the start of the program in the early 2000s, an increase in common species diversity has been observed for both groups. While a large portion of this increase can be attributed to climate change, other factors such as agricultural promotion measures contributed as well. However, only a subset of species benefited from these changes, and over time, species communities of both plants and butterflies became more homogeneous, indicating biotic homogenization. It is likely that these changes also impacted plant-pollinator interactions. For example, the overall increase in plant species richness was mostly driven by wind-pollinated species. In contrast, species with complex flowers, which are essential for specialized groups of flower-visiting insects profited less. The presentation will end with a look forward, identifying current gaps in the Swiss monitoring system and discussing approaches to address these gaps.