Periodic Reporting for period 1 - VegTrends (Assessing long-term trends in the vegetation of European habitats and evaluating the effectiveness of protected areas)
Berichtszeitraum: 2022-10-17 bis 2024-10-16
Biodiversity underpins life on Earth, providing essential ecological, economic, and cultural services critical to human well-being. However, ecosystems worldwide are increasingly being transformed, degraded, and fragmented. Species extinction rates now surpass historical background levels, a significant portion of natural habitats has been lost, and many ecosystem functions and services are under severe threat.
In Europe, over 30% of terrestrial habitats have been classified as "threatened," primarily due to agricultural intensification, urbanization, climate change, and pollution. Meanwhile, the effectiveness of protected areas in safeguarding biodiversity remains a topic of ongoing debate, partly due to a lack of long-term data to assess conservation outcomes.
Assessing biodiversity changes is complex and requires comprehensive approaches. Yet, most studies addressing vegetation change have been local in scope, focusing on single habitats without testing the exceptionality of observed trends. These studies often investigate only one level of biological organization, primarily emphasizing taxonomic diversity while neglecting other important aspects. At the same time, despite numerous studies examining the efficiency of protected areas—such as comparing species richness in protected versus non-protected areas—there remains a significant gap in evidence regarding their overall effectiveness. This gap includes evaluations of biological outcomes over time, consideration of counterfactual scenarios, and the incorporation of multiple facets of biodiversity.
Resurveying studies offer a promising approach to quantifying temporal changes in biodiversity across previously inaccessible spatial and temporal scales, and thus provide an unparalleled opportunity to explore the patterns and drivers of historical changes in European plant communities.
Given that plants are foundational components of habitats, robust, long-term assessments of changes in plant communities are critical for establishing baseline data for biodiversity monitoring, guiding conservation planning, and implementing effective measures to mitigate biodiversity loss.
In this context, VegTrends aimed to produce the first comprehensive and representative report on temporal trends in the vegetation of European open habitats by assessing long-term trends in the vegetation of open European habitats and evaluating the effectiveness of protected areas in conserving these habitats.
In Europe, over 30% of terrestrial habitats have been classified as "threatened," primarily due to agricultural intensification, urbanization, climate change, and pollution. Meanwhile, the effectiveness of protected areas in safeguarding biodiversity remains a topic of ongoing debate, partly due to a lack of long-term data to assess conservation outcomes.
Assessing biodiversity changes is complex and requires comprehensive approaches. Yet, most studies addressing vegetation change have been local in scope, focusing on single habitats without testing the exceptionality of observed trends. These studies often investigate only one level of biological organization, primarily emphasizing taxonomic diversity while neglecting other important aspects. At the same time, despite numerous studies examining the efficiency of protected areas—such as comparing species richness in protected versus non-protected areas—there remains a significant gap in evidence regarding their overall effectiveness. This gap includes evaluations of biological outcomes over time, consideration of counterfactual scenarios, and the incorporation of multiple facets of biodiversity.
Resurveying studies offer a promising approach to quantifying temporal changes in biodiversity across previously inaccessible spatial and temporal scales, and thus provide an unparalleled opportunity to explore the patterns and drivers of historical changes in European plant communities.
Given that plants are foundational components of habitats, robust, long-term assessments of changes in plant communities are critical for establishing baseline data for biodiversity monitoring, guiding conservation planning, and implementing effective measures to mitigate biodiversity loss.
In this context, VegTrends aimed to produce the first comprehensive and representative report on temporal trends in the vegetation of European open habitats by assessing long-term trends in the vegetation of open European habitats and evaluating the effectiveness of protected areas in conserving these habitats.
Work performed for this project involved the processing and integration of vegetation, functional, and phylogenetic data to compute metrics summarizing changes in biodiversity facets. At the outset, I requested and obtained data from ReSurveyEurope, carrying out data cleaning and selection. Simultaneously, I retrieved functional and phylogenetic information and matched these to taxonomic data. Subsequently, I computed dissimilarity indices for each diversity facet (taxonomic, functional, and phylogenetic) using both presence-absence and abundance data. Additionally, I developed and executed null models for the three diversity facets to test observed trends against null expectations. I also calculated metrics summarizing changes in occurrence frequency and cover for individual species, and used them for further analysis. Results were presented at five international scientific conferences, and a manuscript is currently in preparation.
The main findings from VegTrends reveal that, over the past decades, European open habitats have undergone significant changes at both the community and species levels, affecting their taxonomic, phylogenetic, and functional diversity. These changes varied across habitats and diversity facets. Partitioning dissimilarity into species gains and losses revealed differing patterns, with dissimilarity being driven by either gains or losses in different habitats. Functional and phylogenetic diversity also showed notable shifts; phylogenetic changes were generally smaller, while functional changes were highly variable and often exceeded taxonomic changes, reflecting substantial alterations in community functions. Habitat-specific null models confirmed that observed dissimilarity values were mostly non-random and exceeded null expectations across diversity facets. Species-level analyses revealed that nearly one in five of the tested species showed significant trends in occurrence and frequency. These findings provide a preliminary assessment of decadal shifts in the vegetation of open habitats at the European level and highlight the need for continuous monitoring to ensure effective conservation.