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ABSTRACT Aim Location Taxon Methods Results Main Conclusions Endemic species, characterised by limited geographic ranges, face a high risk of extinction. The neotropical region harbours diverse ecosystems and a substantial number of endemic species, thus identifying areas of high endemism is crucial for protecting unique and threatened species and ecosystems. Vascular epiphytes—nonparasitic plants that grow on other plants without contact with the soil—exhibit remarkable diversity in the neotropics, with 63% of the global total of ca. 31,000 epiphyte species found in this region. This study aims to describe the endemism centres for the five most species‐rich families of vascular epiphytes.Neotropics.Tracheophyta.We gathered information from free‐access web repositories, specific epiphytic plant databases and scientific and grey literature on epiphyte species of the families Araceae, Bromeliaceae, Orchidaceae, Piperaceae and Polypodiaceae within the neotropical realm as defined by Morrone et al. (2022). Geographical ranges were calculated using minimum convex polygons for 11,446 species, accounting for about 70% of all epiphyte species in the neotropics. Narrow endemic species were defined as those within the first quartile of the density distribution of geographic range sizes within each family and we identified endemism centres for epiphyte species of the five families.Our study identified endemism centres for vascular epiphyte species in several biogeographic provinces, including Paramo, Cauca, Guatuso‐Talamanca, Atlantic, Yungas and Puntarenas‐Chiriqui. Orchidaceae, accounting for most of the analysed species (71%), drove the overall distribution pattern; however, endemism patterns varied among families.Regions with high epiphyte richness exhibited a greater proportion of endemic species, though the composition of epiphyte species varied considerably among regions. The endemism centres identified in this study could be prioritised as conserved and protected areas. [ABSTRACT FROM AUTHOR]

This article discusses the importance of reproducibility in vegetation research and the role of data and code sharing in achieving this. The International Association for Vegetation Science (IAVS) has implemented a mandatory "Data Availability Statement" in the Journal of Vegetation Science (JVS) and Applied Vegetation Science (AVS) to improve transparency and reproducibility. The article examines the availability and accessibility of data and code in these journals over the past 10 years and finds a significant increase in data availability since 2019, while code availability has increased more slowly. The authors suggest that more information and training on data and code sharing practices could further improve reproducibility. They also acknowledge the need to consider issues of governance, protection of local community knowledge, and equity in data use. The text discusses two articles that were considered as award candidates for the Journal of Vegetation Science. The first article by Léo Delalandre and his co-authors examines the response of different plant groups to management intensification in Mediterranean rangelands. They found that annuals and perennials responded differently to the management gradient, highlighting the importance of considering different plant groups in studies of trait-environment relationships. The second article by Nicola Alessi and colleagues addresses the effects of probabilistic versus preferential sampling on analytical results in vegetation science. They compared two data sets of forest vegetation plots and found that probabilistic sampling was better for estimating species richness and diversity, while preferential sampling was better for detecting forest-specialist [Extracted from the article]

Abstract: We assessed the diversity, vertical distribution, and the effect of structural and geographical factors on the diversity of vascular epiphyte assemblages (VEAs) in two forest types in the 'El [...]

Understanding the degree to which deterministic and stochastic processes drive community assembly is an ongoing focus of research in community ecology. This effort is strongly biased towards ground‐rooted plants, resulting in a limited understanding of communities of other life‐forms, such as structurally dependent plants. Vascular epiphytes are sessile organisms growing non‐parasitically on three‐dimensional dynamic patches, their host plants. Since negative biotic interactions are thought to play a minor role in vascular epiphyte assembly, in some forests, epiphytes are fascinating model organisms to understand the prevalence of environmental filtering in shaping community assembly.We assessed the contribution of deterministic processes on the temporal dynamics of vascular epiphyte assemblages by tracking the direction of changes in composition, species richness and abundance in time at different ecological and spatial scales. We made use of a globally unique dataset from a lowland forest in Panama. We predict that if niche‐based mechanisms dominate, (a) temporal changes will be directional and (b) differences in the species composition of epiphyte assemblages will be primarily related to host plant characteristics and, to a lesser degree, to the distance between host trees.We show that temporal changes in vascular epiphyte assemblages were directional at different ecological scales, such as the forest patch, host species or individual tree assemblages. Epiphyte assemblages on host trees became more similar in their composition over time than expected by chance, and these changes were not due to homogenisation. While host characteristics were related to these directional changes, host structure rather than host identity was more strongly related to variation in assemblage dissimilarity, while spatial distance among trees was of minor importance. The observed directionality was primarily due to environmental filtering.This study provides the first evidence that niche‐based mechanisms dominate the dynamics of vascular epiphyte assemblages. Analysing temporal patterns of vascular epiphyte assemblages is a first important step towards understanding the relative importance of deterministic processes for diversity maintenance of one of the most diverse plant groups in the tropics.Synthesis. Directionality in the temporal changes of epiphyte assemblages suggests that niche‐based mechanisms dominate these temporal changes. Host size over host identity is the most important environmental filter for epiphyte assemblages establishment. [ABSTRACT FROM AUTHOR]

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Questions: The importance of tropical rainforest gap dynamics in biodiversity maintenance is not fully understood, in particular for taxa other than trees and lianas. We used epiphylls on rainforest leaves to study the importance of leaf‐ and forest‐scale succession in determining biodiversity patterns by characterizing community change with leaf age in gaps and closed‐forest habitats. We asked: (1) Do epiphylls show specialization for leaf and forest successional stages? (2) Can early‐ and late‐successional epiphyllous species be recognized at these two scales? (3) How do epiphyll presence, species richness, and cover change with leaf and forest successional stages? Location: Barro Colorado Island, Panama. Method: Data were collected from 420 leaves, in three age groups and at two heights on shrubs in gaps and closed forest. We calculated turnover and nestedness components of dissimilarity to evaluate the importance of species replacement or accumulation during leaf and forest succession. Using generalized linear mixed models we determined what factors explain epiphyll species occurrence, richness and cover. Results: Closed forest contained more liverwort and lichen specialist species than gaps. Specialist species were identified for older leaves only. Dissimilarity between leaves within age groups was dominated by turnover within and between forest successional stages. Dissimilarity between leaf age groups, at the site level, was dominated by nestedness, i.e., species accumulation. Both in forest and gaps, epiphyll presence and cover increased with leaf age for all taxa except fungi, while species richness increased only for lichens. Conclusion: Early and late forest successional stages both contribute to epiphyll species richness by harboring specialized species. Among leaf successional stages, young leaves contain a mere subset of the species found on older leaves. Epiphyll communities do not follow classic succession, in the sense of changes being driven by species replacement, but are characterized by species accumulation through time. [ABSTRACT FROM AUTHOR]

Earlier snowmelt changes spring stress exposure and growing-season length, possibly causing shifts in plant species dominance. If such shifts involve trees, this may lead to changes in treeline position. We hypothesized that earlier snowmelt would negatively affect the performance of tree seedlings near the treeline due to higher spring stress levels, but less so if seedlings were protected from the main stress factors of night frosts and excess solar radiation. We exposed seedlings of five European treeline tree species: Larix decidua, Picea abies, Pinus cembra, Pinus uncinata, and Sorbus aucuparia to two snow-cover treatments (early and late melting, with about two weeks difference) combined with reduced sky exposure during the day (shading) or night (night warming), repeated in two years, at a site about 200 m below the regional treeline elevation. Physiological stress levels (as indicated by lower Fv/Fm) in the first weeks after emergence from snow were higher in early-emerging seedlings. As expected, shade reduced stress, but contrary to expectation, night warming did not. However, early- and late-emerging seedlings did not differ overall in their growth or survival, and the interaction with shading was inconsistent between years. Overall, shading had the strongest effect, decreasing stress levels and mortality (in the early-emerging seedlings only), but also growth. A two-week difference in snow-cover duration did not strongly affect the seedlings, although even smaller differences have been shown to affect productivity in alpine and arctic tundra vegetation. Still, snowmelt timing cannot be discarded as important for regeneration in subalpine conditions, because (1) it is likely more critical in very snow-rich or snow-poor mountains or landscape positions; and (2) it can change (sub)alpine vegetation phenology and productivity, thereby affecting plant interactions, an aspect that should be considered in future studies. [ABSTRACT FROM AUTHOR]