Global biodiversity has changed tremendously over the past 50 years due to the impact of
anthropogenic drivers such as land use change, direct exploitation, pollution, climate change and
invasive species. The eLTER network's biodiversity surveys provide a unique opportunity to investigate
these changes and to assess their impacts. The present report has two main objectives. First, it will
investigate whether eLTER data are suitable for analysing long‐term biodiversity change at the
European scale and whether these changes can be linked to potential drivers. The second aim is to
evaluate eLTER workflows and services that benefit the scientific community and to provide
recommendations for the further development of the eLTER Research Infrastructure. To address the
first objective, we conducted a case study in which we analysed changes in the species composition
of plant communities at eLTER sites. The experiences gained from this work were used to address the
second objective.
Changes in species composition within local communities are among the most pronounced
components of biodiversity change. Colonisations, extinctions and shifts in abundances can lead to a
homogenisation or heterogenisation of communities. By using eLTER vegetation time series covering
the period from 1995 to 2018 we investigated the relative importance of these processes by applying
two different approaches. First, we partitioned temporal changes in spatial β‐diversity into
colonisation and extinction events and explored to what extent both processes have contributed to
the homogenization or heterogenisation of local plant communities. Second, we analysed temporal
β‐diversity to identify sites that have extraordinarily changed.
Spatial differentiation among plant communities increased over time. This change was influenced
more by extinctions than by colonisations. Extinctions resulting in a heterogenisation of plant
communities is an indication of a stronger reduction of widespread species as compared to rare
species. The analysis of temporal β‐diversity likewise showed that extinctions had a more pronounced
effect on community composition than colonisations. Further analysis indicated that species losses
and gains over time may be related to changing precipitation patterns at eLTER sites.
The case study showed that eLTER biodiversity data are principally well suited to answer questions
concerning biodiversity change at the continental scale. However, the study also points at limitations
resulting from restricted spatial representativity, low sampling frequencies and various types of
heterogeneity in the data. Recommendations are made to increase representativeness and to specify
existing eLTER Standard Observations. Further considerations concern the development of IT services,
with a focus on the documentation of metadata, data acquisition, quality control, harmonisation of
variables and networking with other initiatives.