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Question: Inter‐annual species mobility within a community might support species co‐existence in species‐rich ecosystems. We asked how species mobility within a highly diverse grassland community is affected by species traits and how external conditions (management) affect mobility. Location: Semi‐natural wet meadow in southern Bohemia, Czech Republic (48°57′ N, 14°36′ E, 510 m a.s.l.). Methods: A manipulative experiment comprising mowing, fertilization, and removal of the dominant species Molinia caerulea was established, in factorial design, in a semi‐natural species‐rich meadow in 1994. Rooting presence of all species was recorded in individual 0.1 m × 0.1 m cells grid within 0.5 m × 0.5 m permanently fixed quadrats. We used a 14‐year continuous time series to evaluate species persistence (ability to stay in a cell over time) in each plot, using the point correlation coefficient (V), and related persistence to different plant traits. At the community level we also determined mobility, as floristic dissimilarity of the individual cell and the whole 0.5 m × 0.5 m quadrat across contiguous years. Results: The differences in traits and mobility among species were remarkable: "sitters," retaining their spatial position (e.g. Succisa pratensis, Carex umbrosa) had tougher leaves, usually had shoot generation overlap, a rosette and did not have effective clonal spreading; "travelers" (e.g. Lysimachia vulgaris, Lathyrus pratensis) changed their position frequently and had opposite traits. Of the experimental factors, only mowing affected mobility, increasing persistence, but all factors modified species mobility ranking slightly. Against expectation, species richness was negatively correlated with community mobility. Conclusions: A high degree of mobility in species‐rich meadows does not necessarily enhance diversity. However, a functional differentiation between more mobile and fixed species can be expected within co‐existing species. Species mobility is highly species‐specific and less affected by management. [ABSTRACT FROM AUTHOR]

The relationship between diversity and ecosystem functioning is often studied by biodiversity experiments. Traditionally, the mechanisms behind biodiversity effects observed in these experiments have been evaluated by relative yield, overyielding and Loreau and Hector's additive partitioning of net biodiversity effect, and more recently by linear-model-based methods such as Kirwan's diversity—interaction model and Bell's random partition model. We compared data required and results given by these traditional and linear-model-based methods using three data sets: a simulated data set and two pot biodiversity experiments. For the simulated data, we also compared expected outputs based on defined ecological species traits with actual outcomes of the methods. BEF experiments were designed to answer five fundamental questions: Q1) How does sown species richness change ecosystem functioning? Q2) What ecological mechanisms cause this change? Q3) How does the importance of ecological mechanisms change with sown species richness? Q4) Which species are responsible for given ecological mechanisms? Q5) How do other experimental treatments change answers to all questions above? We show that all methods were capable of answering Q1 and to some extent also Q5 although different methods use different procedures to reach the answer. Concerning Q2–Q4, we found that traditional methods provide more detailed insight into the ecological mechanisms than the linear-model-based methods which leave us just with brief information. A direct comparison between traditional biodiversity effects and effects from linear-model-based methods showed that species interactions from the diversity—interaction model were significantly positively correlated with the net effect, while species identity effects from diversity—interaction model were related to the species relative yield. The selection of an appropriate method for BEF experiment analysis thus depends on the questions we ask which in turn also affect the design of the BEF experiment. [ABSTRACT FROM AUTHOR]

Linking diversity to biological processes is central for developing informed and effective conservation decisions. Unfortunately, observable patterns provide only a proportion of the information necessary for fully understanding the mechanisms and processes acting on a particular population or community. We suggest conservation managers use the often overlooked information relative to species absences and pay particular attention to dark diversity (i.e., a set of species that are absent from a site but that could disperse to and establish there, in other words, the absent portion of a habitat-specific species pool). Together with existing ecological metrics, concepts, and conservation tools, dark diversity can be used to complement and further develop conservation prioritization and management decisions through an understanding of biodiversity relativized by its potential (i.e., its species pool). Furthermore, through a detailed understanding of the population, community, and functional dark diversity, the restoration potential of degraded habitats can be more rigorously assessed and so to the likelihood of successful species invasions. We suggest the application of the dark diversity concept is currently an underappreciated source of information that is valuable for conservation applications ranging from macroscale conservation prioritization to more locally scaled restoration ecology and the management of invasive species. [ABSTRACT FROM AUTHOR]