Plant traits-the morphological, anatomical, physiological, biochemical and phenological characteristics of plants-determine how plants respond to environmental factors, affect other trophic levels, and influence ecosystem properties and their benefits and detriments to people. Plant trait data thus represent the basis for a vast area of research spanning from evolutionary biology, community and functional ecology, to biodiversity conservation, ecosystem and landscape management, restoration, biogeography and earth system modelling. Since its foundation in 2007, the TRY database of plant traits has grown continuously. It now provides unprecedented data coverage under an open access data policy and is the main plant trait database used by the research community worldwide. Increasingly, the TRY database also supports new frontiers of trait-based plant research, including the identification of data gaps and the subsequent mobilization or measurement of new data. To support this development, in this article we evaluate the extent of the trait data compiled in TRY and analyse emerging patterns of data coverage and representativeness. Best species coverage is achieved for categorical traits-almost complete coverage for 'plant growth form'. However, most traits relevant for ecology and vegetation modelling are characterized by continuous intraspecific variation and trait-environmental relationships. These traits have to be measured on individual plants in their respective environment. Despite unprecedented data coverage, we observe a humbling lack of completeness and representativeness of these continuous traits in many aspects.We, therefore, conclude that reducing data gaps and biases in the TRY database remains a key challenge and requires a coordinated approach to data mobilization and trait measurements. This can only be achieved in collaboration with other initiatives. Geosphere-Biosphere Program (IGBP) and DIVERSITAS, the TRY database (TRY-not an acronym, rather a statement of sentiment; https ://www.try-db.org; Kattge et al., 2011) was proposed with the explicit assignment to improve the availability and accessibility of plant trait data for ecology and earth system sciences. The Max Planck Institute for Biogeochemistry (MPI-BGC) offered to host the database and the different groups joined forces for this community-driven program. Two factors were key to the success of TRY: the support and trust of leaders in the field of functional plant ecology submitting large databases and the long-term funding by the Max Planck Society, the MPI-BGC and the German Centre for Integrative Biodiversity Research (iDiv) Halle-Jena-Leipzig, which has enabled the continuous development of the TRY database.

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Typha is an iconic wetland plant found worldwide. Hybridization and anthropogenic disturbances have resulted in large increases in Typha abundance in wetland ecosystems throughout North America at a cost to native floral and faunal biodiversity. As demonstrated by three regional case studies, Typha is capable of rapidly colonizing habitats and forming monodominant vegetation stands due to traits such as robust size, rapid growth rate, and rhizomatic expansion. Increased nutrient inputs into wetlands and altered hydrologic regimes are among the principal anthropogenic drivers of Typha invasion. Typha is associated with a wide range of negative ecological impacts to wetland and agricultural systems, but also is linked with a variety of ecosystem services such as bioremediation and provisioning of biomass, as well as an assortment of traditional cultural uses. Numerous physical, chemical, and hydrologic control methods are used to manage invasive Typha, but results are inconsistent and multiple methods and repeated treatments often are required. While this review focuses on invasive Typha in North America, the literature cited comes from research on Typha and other invasive species from around the world. As such, many of the underlying concepts in this review are relevant to invasive species in other wetland ecosystems worldwide.

Summary Ecological restoration is critical for mitigating habitat loss and providing ecosystem services. However, restorations often have lower diversity than remnant, reference sites. Phylogenetic diversity is an important component of biodiversity and ecosystem function that has only recently been used to evaluate restoration outcomes. To move towards prediction in the restoration of biodiversity, it is necessary to understand how phylogenetic diversity of restorations compares with that of reference sites, and where deficits are found, to evaluate factors constraining phylogenetic diversity. We quantified plant taxonomic and phylogenetic diversity in eastern tallgrass prairie, one of the most endangered ecosystems on earth. We measured diversity at large (site) and small (plot) scales in 19 restored prairies and compared patterns with those from 41 remnant prairies. To evaluate how environmental conditions and management actions influence outcomes, we tested the effects of soil properties and seed mix composition on diversity of restorations. Restored prairies were less phylogenetically diverse than remnants at both spatial scales. On the other hand, the total species richness of remnant and restored prairies did not significantly differ, but remnants had higher native richness. Restored communities were taxonomically and phylogenetically distinct from remnants. Soil properties (moisture and pH) influenced phylogenetic diversity and composition. There were positive relationships between the taxonomic and phylogenetic diversity of seed mixes and resulting diversity of planted assemblages (excluding volunteer species). Species in seed mixes were more closely related than expected by chance, and several clades found in remnant prairies were missing from seed mixes. Synthesis and applications. Restored tallgrass prairies had lower phylogenetic diversity than remnant prairies, which may contribute to the widely observed phenomenon of restorations not being functionally equivalent to reference sites. It is encouraging for restoration efforts that seed mix phylogenetic diversity predicted phylogenetic diversity of planted assemblages. This indicates that designing phylogenetically diverse seed mixes for restoration is beneficial. In addition, clades found in reference sites that are missing from restoration seed mixes could be added to new or existing restorations to reduce gaps in phylogenetic diversity. Further work on the effects of management on phylogenetic diversity is needed to advance restoration of biodiversity.

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There are often lag phases in plant invasions, seemingly dormant periods between arrival in a new range and rapid population growth. Lags impede prioritization of invasive-species control efforts: when eradication is most feasible, it is often unclear whether a species is benign or a potentially harmful ''sleeper weed.'' I used herbarium records to estimate lag phases for invasive or potentially invasive plant species in three regions of the upper Midwest. I tested whether factors related to species' invasion epidemiology, traits, or the habitats they invade were correlated with lag lengths. From an initial pool of 151 species, there were sufficient records to test for lags in 76 for northern Wisconsin, 90 for southern Wisconsin, and 91 for the southern Lake Michigan region. Lags were identified in 77% (197) of these 257 datasets and ranged from 3-140 years with a mean of 47.3 ± 34.6 (SD). Lags differed by native range, introduction pathway, growth form and habit, dispersal mode, flowering phenology, pollination mode for a subset of species, and breadth, light availability, and water availability of invaded habitats. However, estimated lags were highly variable and tested factors did not have strong explanatory power. Exotic species comprised an increasing proportion of total herbarium records. Of the species with known introduction pathways, 85% were intentionally introduced, mainly as ornamentals. The long durations, high variability, and low predictability of lags, along with human culpability for an increasingly non-native flora, support a cautious approach to species introductions.

The mechanisms by which invasive plants displace native species are often not well elucidated, limiting knowledge of invasion dynamics and the scientific basis for management responses. Typha 9 glauca Godr. invades wetlands throughout much of North America. Like other problematic wetland invaders, Typha is large, grows densely, and leaves behind copious litter. It thus has the potential to impact wetlands both in life and after death. We assessed patterns in field settings and used simulated wetland-plant communities to experimentally test abiotic and community responses to live Typha, Typha litter, and water-level differences (confounded in the field) using a full-factorial design. In general, litter was a stronger driver of change than live Typha. The greatest impacts were seen where, as in nature, live and dead Typha co-occurred. Live-Typha treatments did not differ from controls in light or temperature conditions but did reduce community biomass and alter community composition. Litter strongly affected light, temperature and its variability, community and species-level plant biomass, and community composition. Interactions between live Typha and litter affected aspects of plant-community composition. Advantageously for Typha, interspecific litter effects were not mirrored by intraspecific suppression of live Typha. These findings clarify how Typha is such an effective invader. Similar mechanisms are likely involved in invasions by other plant species, particularly in wetlands. Managers should respond quickly to new Typha invasions and, when dealing with established stands, remove litter in addition to eradicating live plants.