Weeds shift from generalist to specialist: narrowing of ecological niches along a north-south gradient

There are changes in the realized niches of species along environmental gradients, especially at the edge of their distribution where they become more specialized. A classical case is weeds of the Caucalidion alliance that spread with agriculture from the Fertile Crescent and thrive in a wide range of climates that differ from that prevailing in their native area. We used large data sets of vegetation collected in central Europe (3383 plots) and north-western Balkans (4505 plots) and used a co-occurrence species algorithm to calculate the specialist/generalist status of weed species. The change in the width of the ecological niches was tested using target species. Our assumptions were confirmed as the same characteristic species of Caucalidion weed vegetation in the north-western Balkans are more specialized in central Europe, where they occupy more basic habitats that vary less in terms of soil reaction. Testing niche theory using real data is especially important for nature conservation because specialists are more prone to decline in abundance or to go extinct

A framework for understanding how biodiversity patterns unfold across multiple spatial scales in urban ecosystems

Whether cities are more or less diverse than surrounding environments, and the extent to which non-native species in cities impact regional species pools, remain two fundamental yet unanswered questions in urban ecology. Here we offer a unifying framework for understanding the mechanisms that generate biodiversity patterns across taxonomic groups and spatial scales in urban systems. One commonality between existing frameworks is the collective recognition that species co-occurrence locally is not simply a function of natural colonization and extinction processes. Instead, it is largely a consequence of human actions that are governed by a myriad of social processes occurring across groups, institutions, and stakeholders. Rather than challenging these frameworks, we expand upon them to explicitly consider how human and non-human mechanisms interact to control urban biodiversity and influence species composition over space and time. We present a comprehensive theory of the processes that drive biodiversity within cities, between cities and surrounding non-urbanized areas and across cities, using the general perspective of metacommunity ecology. Armed with this approach, we embrace the fact that humans substantially influence β-diversity by creating a variety of different habitats in urban areas, and by influencing dispersal processes and rates, and suggest ways how these influences can be accommodated to existing metacommunity paradigms. Since patterns in urban biodiversity have been extensively described at the local or regional scale, we argue that the basic premises of the theory can be validated by studying the β-diversity across spatial scales within and across urban areas. By explicitly integrating the myriad of processes that drive native and non-native urban species co-occurrence, the proposed theory not only helps reconcile contrasting views on whether urban ecosystems are biodiversity hotspots or biodiversity sinks, but also provides a mechanistic understanding to better predict when and why alternative biodiversity patterns might emerge

Agroekologie: východiska pro udržitelné zemědělské hospodaření

Kniha ukazuje, že k dlouhodobému řešení problémů moderního zemědělství je možno dospět jedině restrukturalizací a takovou správou zemědělských systémů, která změní jejich podobu a fungování na základě agroekologie. Agroekologie je věděcká disciplína, která využívá ekologické teorie ke studiu, designu, managementu a hodnocení produktivních zemědělských systémů, jež současně chrání přírodní zdroje. Kniha se zaměřuje jak na tradiční obhospodařování pro praktické zemědělce tak sofistikované využití ekosystémových poznatků. Kniha slouží jako učebnice pro moderní zemědělský provoz tak pro akademickou obec

Benchmarking plant diversity of Palaearctic grasslands and other open habitats

Abstract Aims: Understanding fine-grain diversity patterns across large spatial extents is fundamental for macroecological research and biodiversity conservation. Using the GrassPlot database, we provide benchmarks of fine-grain richness values of Palaearctic open habitats for vascular plants, bryophytes, lichens and complete vegetation (i.e., the sum of the former three groups). Location: Palaearctic biogeographic realm. Methods: We used 126,524 plots of eight standard grain sizes from the GrassPlot database: 0.0001, 0.001, 0.01, 0.1, 1, 10, 100 and 1,000 m² and calculated the mean richness and standard deviations, as well as maximum, minimum, median, and first and third quartiles for each combination of grain size, taxonomic group, biome, region, vegetation type and phytosociological class. Results: Patterns of plant diversity in vegetation types and biomes differ across grain sizes and taxonomic groups. Overall, secondary (mostly semi-natural) grasslands and natural grasslands are the richest vegetation type. The open-access file ”GrassPlot Diversity Benchmarks” and the web tool “GrassPlot Diversity Explorer” are now available online (https://edgg.org/databases/GrasslandDiversityExplorer) and provide more insights into species richness patterns in the Palaearctic open habitats. Conclusions: The GrassPlot Diversity Benchmarks provide high-quality data on species richness in open habitat types across the Palaearctic. These benchmark data can be used in vegetation ecology, macroecology, biodiversity conservation and data quality checking. While the amount of data in the underlying GrassPlot database and their spatial coverage are smaller than in other extensive vegetation-plot databases, species recordings in GrassPlot are on average more complete, making it a valuable complementary data source in macroecology

TRY plant trait database - enhanced coverage and open access

10.1111/gcb.14904GLOBAL CHANGE BIOLOGY261119-18