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Importance of nurse plants structuring plant communities is well‐appreciated at local scales, yet the effect of a single nurse on large scales has been neglected in analyses. So far, studies only use environmental gradients within one type of ecosystem and tend to generalize the nurse effects.To assess how the effect of a single nurse species is modulated by different environmental settings, interactions between the shrub Vachellia caven and the surrounding plant communities were evaluated at 481 paired plots (outside vs. underneath the plant crown), in 39 sites across two distribution ranges, the Mediterranean west and the mostly subtropical east of the Andes Mountains (covering ca. 2 × 106 km2).Cover, abundance and richness of perennial plants underneath and outside V. caven were used as response variables to estimate an index indicative of plant interactions (relative interaction index [RII]) and tested how this was affected by the rainfall gradient and distribution range.Overall, RII responses to rainfall gradients had low conditional R2 (~0.25) in this large scale of analysis, but were significantly different between ranges: the RII followed a quadratic trend across the rainfall gradient in the western range, while this relationship was positive and close to linear at the eastern range.Then, by projecting the RII models (i.e. for abundance, cover and richness) spatially through a consensus map, we show that most positive effects of V. caven are geographically found in dissimilar areas: the central part of Chile (western range) and across the Paraná River (eastern range).When local fine‐scale predictors (i.e. annual herbs' cover and height, and herbivores' faeces cover) were used to model each response variable at the plot level (underneath or outside V. caven), we observed similar trends as when we considered only the large‐scale predictors.Synthesis. Here, we show that the effect of the same nurse species on neighbouring plant communities can be very different depending on ranges of distribution, stressing that its ecological function cannot be generalized and not only depends on local factors but also is large‐scale context‐dependent. [ABSTRACT FROM AUTHOR]

The presence of Andean plant genera in moist forests of the Brazilian Atlantic Coast has been historically hypothesized as the result of cross-continental migrations starting at the eastern Andean flanks. Here we test hypotheses of former connections between the Atlantic and Andean forests by examining distribution patterns of selected cool and moist-adapted plant arboreal taxa present in 54 South American pollen records of the Last Glacial Maximum (LGM), ca. 19–23 cal ka, known to occur in both plant domains. Pollen taxa studied include Araucaria, Drimys, Hedyosmum, Ilex, Myrsine, Podocarpus, Symplocos, Weinmannia, Myrtaceae, Ericaceae and Arecaceae. Past connectivity patterns between these two neotropical regions as well as individual ecological niches during the LGM were explored by cluster analysis of fossil assemblages and modern plant distributions. Additionally, we examined the ecological niche of 137 plant species with shared distributions between the Andes and coastal Brazil. Our results revealed five complex connectivity patterns for South American vegetation linking Andean, Amazonian and Atlantic Forests and one disjunction distribution in southern Chile. This study also provides a better understanding of vegetation cover on the large and shallow South American continental shelf that was exposed due to a global sea level drop. [ABSTRACT FROM AUTHOR]

Alexander von Humboldt's depictions of mountain vegetation are among the most iconic nineteenth century illustrations in the biological sciences. Here we analyse the contemporary context and empirical data for all these depictions, namely the Tableau physique des Andes (1803, 1807), the Geographiae plantarum lineamenta (1815), the Tableau physique des Îles Canaries (1817), and the Esquisse de la Géographie des plantes dans les Andes de Quito (1824/1825). We show that the Tableau physique des Andes does not reflect Humboldt and Bonpland's field data and presents a flawed depiction of plant occurrences and vertical succession of vegetation belts, arising from Humboldt's misreading of La Condamine's description (1751). Humboldt's 1815 depiction, by contrast, shows a distribution of high-vegetation belts that is consistent with La Condamine's description, while the 1824 depiction drops innovations made in 1815 and returns to simply showing numerous species' names, thus not applying Humboldt's own earlier zonation framework. Our analysis of contemporary reactions to Humboldt's TPA includes Francis Hall's posthumously published 1834 illustration of Andean plant zonation near Quito and Humboldt's reaction to Hall's critique. Throughout his work on plant geography, Humboldt disregarded some of his own observations, or confused them. At stake was his reputation as an innovator in the field of plant geography and a discoverer of the sequence of high-elevation vegetation belts on the world's mountains. [ABSTRACT FROM AUTHOR]

Augusto Weberbauer published, in 1922, the first vegetation map of Peru, where he showed and described twenty-five plant formations, grouped into six categories, considering altitudinal ranges defined according to their temperature. Within these categories are the microthermal formations that are generally found above 3400 masl and have a wide latitudinal distribution throughout the Peruvian Andes. To revalue that historical map, we present, firstly, the results of digitalization and estimation of extension of the four microthermal vegetation formations identified by Weberbauer, and secondly, the findings of cartographic contrasting between these microthermal formations, and the high Andean vegetation covers as classified in the most updated map on this subject. Weberbauer mapped an area of 183.445,30 km² for the four microthermal vegetation formations: typical high Andean formations (61,67%); microthermal herbaceous steppe (17,93%); microthermal tolar (17,47%); glaciers and perpetual snow (2,93%). Likewise, a cartographic comparison showed that 63,92% of the territory currently occupied by high Andean vegetation cover in Peru is coincident with that mapped by Weberbauer as microthermal vegetation formations. These results contribute to the understanding of the evolution of these formations, which are under climate change and anthropogenic pressures. [ABSTRACT FROM AUTHOR]

Widespread changes in temperature and precipitation patterns present plant species with new and combined stresses that affect their performance and distribution. Functional traits are indicators of plant resource use–acquisition strategies and thus they are commonly used to understand the geographic distributions of plant species and species' potential responses to climate change. To date, most studies have targeted a few easy‐to‐measure leaf traits even though other traits, such as climatic tolerances, could provide valuable information directly related with species' current and future distributions. Here, we measured both leaf functional traits and indices of physiological tolerance to heat (T50) and drought (cell membrane stability) in 28 woody bamboo populations from 22 narrow‐ranged species along a > 3000 m elevation gradient in the southern Peruvian Andes. We found that bamboo leaf functional traits remain fairly constant with a combination indicative of an acquisitive strategy (low leaf mass area and high nitrogen per mass) along the elevation gradient, despite drastic changes in environment and fast species turnover. Heat and drought tolerances of bamboos varied widely along the gradient and were negatively correlated to each other. Drought tolerance of bamboo populations was positively related with elevation and with precipitation seasonality while heat tolerance decreased at higher, colder elevations. When analyzed for individuals within each species or for individuals within each elevation, the two metrics of climatic tolerances did not show a consistent relationship, contrasting with the expectation of a potential tradeoff between heat and drought tolerance. We also found that the measured leaf functional traits were not good predictors of climatic tolerances. Our results illustrate the diversity and complexity of the relationships between functional strategies and environmental gradients and highlight the limitations of using basic (i.e. 'soft') leaf traits to understand plant distributions and climatic tolerances. [ABSTRACT FROM AUTHOR]

Questions: Given the current multiplicity of threats to pond biodiversity, there is a clear need to examine which environmental drivers determine the composition and distribution of species. Using wetland plants as pond biodiversity surrogates, two questions led to this work: How do wetland plant species assemblages and abundance vary across local‐ and regional‐scale classification schemes in wetlands? How does wetland plant beta‐diversity vary within these wetland classification schemes? Location: Western Patagonia, Argentina, from 36°S to 56°S and from 73°W to 65°W. Methods: Wetland plant distribution constrained by water and climatic factors was analyzed using canonical correspondence analysis. Variance partitioning analysis was performed to assess which classification scheme (phytogeographical units, wetland regions, wetland genesis and hydrogeomorphological types) better explained variation in plant composition. An IndVal analysis was also carried out to detect taxa with the highest association values (indicator taxa) for the different categories of wetland classification. Beta‐diversity was calculated to evaluate variation patterns within classification schemes. Results: Plant distribution was mainly related to site location across the latitudinal gradient, following a decreasing pattern of air temperature from northern to southern wetlands. Variance partitioning analysis confirmed the effectiveness of a regional‐scale classification (wetland regions) in predicting plant associations, and the IndVal analysis also highlighted this classification scheme above the remainder, sustaining the highest number of indicator taxa. Wetland plant beta‐diversity patterns were explained by relatively high species turnover, with species composition showing low nestedness values. Conclusion: Climate factors rather than local characteristics were the main drivers of plant distribution at the wide regional scale analyzed. Wetland region (classification based on climatic criteria) was the most effective scheme in predicting plant associations and sustaining the highest number of indicator taxa. Also, ponds located in the Patagonian Andes and those with a glacigenic origin contribute most to the regional wetland plant diversity. Therefore, these aspects should be taken directly into account in the future delineation of protected areas to increase the resilience of Patagonian wetland habitats and their associated biota, and to maintain the ecosystem services that they provide. [ABSTRACT FROM AUTHOR]

The Neotropical Region (NR) is one of the areas with the most plant diversity globally, and its richness of vascular epiphyte (VE) species is higher than Africa and Asia combined. This richness is a consequence of the heterogeneous climate and geological history of the region, both factors also being responsible for the plant distribution patterns. Here, we aimed to explore the phytogeographic relationships of the VE in the NR using 14,636 identified records from 173 surveys exclusively of VE, carried out in 14 countries and 23 biogeographic provinces, comprising 3849 identified species. We assessed the floristic patterns and relationships with climatic variables by multivariate analysis (cluster and ordination analyses). The clustering formed 13 main groups, partly corresponding to the biogeographic units of the NR. Our results demonstrate consistent floristic patterns confirmed through the analysis of floristic similarity, corroborating previous biogeographic classifications in well-studied areas, while broader patterns were found in poorly studied areas. We found a floristic gradient pattern, which allowed us to understand the relationships between environmental conditions and floristic patterns. Furthermore, we discuss our results under the light of the history that likely shaped the current distribution patterns and richness of the VE in the NR. The VE proved to be an important model for testing biogeographic classifications. We encourage the studies of this synusia in the several geographical gaps that remain in the NR, which undoubtedly will improve further studies and support conservationist policies. [ABSTRACT FROM AUTHOR]

Aim: Climate change is expected to impact mountain biodiversity by shifting species ranges and the biomes they shape. The extent and regional variation in these impacts are still poorly understood, particularly in the highly biodiverse Andes. Regional syntheses of climate change impacts on vegetation are pivotal to identify and guide research priorities. Here we review current data, knowledge and uncertainties in past, present and future climate change impacts on vegetation in the Andes. Location: Andes. Taxon: Plants. Methods: We (i) conducted a literature review on Andean vegetation responses to past and contemporary climatic change, (ii) analysed future climate projections for different elevations and slope orientations at 19 Andean locations using an ensemble of model outputs from the Coupled Model Intercomparison Project 5, and (iii) calculated changes in the suitable climate envelope area of Andean biomes and compared these results to studies that used species distribution models. Results: Future climatic changes (2040–2070) are projected to be stronger at high‐elevation areas in the tropical Andes (up to 4°C under RCP 8.5), while in the temperate Andes temperature increases are projected to be up to 2°C. Under this worst‐case scenario, temperate deciduous forests and the grasslands/steppes from the Central and Southern Andes are predicted to show the greatest losses of suitable climatic space (30% and 17%–23%, respectively). The high vulnerability of these biomes contrasts with the low attention from researchers modelling Andean species distributions. Critical knowledge gaps include a lack of an Andean wide plant checklist, insufficient density of weather stations at high‐elevation areas, a lack of high‐resolution climatologies that accommodates the Andes' complex topography and climatic processes, insufficient data to model demographic and ecological processes, and low use of palaeo data for distribution modelling. Main conclusions: Climate change is likely to profoundly affect the extent and composition of Andean biomes. Temperate Andean biomes in particular are susceptible to substantial area contractions. There are, however, considerable challenges and uncertainties in modelling species and biome responses and a pressing need for a region‐wide approach to address knowledge gaps and improve understanding and monitoring of climate change impacts in these globally important biomes. [ABSTRACT FROM AUTHOR]

Marsupella sect. Stolonicaulon is not speciose and is a commonly neglected section within the genus, which currently includes three species with somewhat similar morphologies (wiry shoots with distanced leaves) and distributions in the mountains of tropical and subtropical regions (SE (Southeast) Asia, the Venezuelan Andes, and the high mountains of SE Brazil). After studying materials that were found to be dissimilar to the "traditional" Marsupella that were collected in the last decade by the authors of this article, it was found that these plants belong to three new-for-science species, and all of these species should be included in Marsupella sect. Stolonicaulon. The newly described species have expanded the boundaries of morphological variability, not only for the section itself, but also for the genus based on two findings: (1) the leaves of Marsupella sect. Stolonicaulon can be either appressed and entire or spaced and deeply divided (thus, the plants could occasionally be similar to Cephaloziella or Anastrophyllum); (2) some species of the section possess regular underleaf production. The first discovery of regular underleaves in Marsupella, as noted in two of the three newly described taxa, is the main morphological novelty described in this paper. The development of regular underleaves is a presumable relict character that brings Marsupella closer to Nardia, which was recently transferred to the Gymnomitriaceae and occupies an isolated position within its own subfamily, Nardioideae. [ABSTRACT FROM AUTHOR]

Aim: Plant distributions are influenced by species' ability to colonize new areas via long‐distance dispersal and propensity to adapt to new environments via niche evolution. We use otobas, a clade of ecologically dominant trees found in low‐to mid‐elevation wet forests, as a system to understand the relative importance of these processes within the Neotropics. Location: Neotropics and global. Taxon: Otoba and entire Myristicaceae. Methods: We resolve the first phylogeny of Otoba the Angiosperms353 loci and plastome sequences from 13 accessions representing seven species. We pair this with the most densely sampled phylogeny of Myristicaceae to date, inferred using publicly available plastid data. We then use environmental niche modelling, biogeographical reconstruction, phylogenetic principle components analysis and Ornstein–Uhlenbeck models to infer biogeography and examine patterns of niche evolution. Results: Myristicaceae has an Old World origin, with a single expansion into the Americas. Divergence dates, fossil evidence and a notable lack of long‐distance dispersal are consistent with a Boreotropical origin of Neotropical Myristicaceae. Mirroring the rarity of dispersal at the family level, Otoba's biogeography is marked by few biogeographical events: two expansions into Central America from a South American ancestor and a single dispersal event across the Andes. This limited movement contrasts with rapid climatic niche evolution, typically occurring across geographically proximate habitats. Main conclusion: Contrasting with previous studies, long‐distance dispersal does not need to be invoked to explain the pantropical distribution of Myristicaceae, nor the biogeography of Otoba. This likely results from the family's relatively large seeds that are dispersed by large‐bodied vertebrates. Instead, rapid niche evolution in Otoba has facilitated its occurrence throughout mesic habitats of the northern Neotropics, including the Amazon rainforest and Andean montane forests. Otoba adds to a growing group of Neotropical plant clades in which climate adaptation following local migration is common, implying an important role of niche evolution in the assembly of the Neotropical flora. [ABSTRACT FROM AUTHOR]

The codling moth (Cydia pomonella (L.)) is an invasive pest of pome fruits introduced to the Americas in the 19–20th centuries. This pest is widespread on both sides of the Andes range separating Argentina and Chile. We performed an analysis of the population genetic variability and structure of C. pomonella in Argentina and Chile using 13 microsatellite markers and sampled C. pomonella from apple as the main host plant along its distribution area (approx. 1,800 km). A total of 22 locations (11 from Chile and 11 from Argentina) were sampled. Significant genetic differentiation was observed among samples from Argentina and Chile (FSC = 0.045) and between all localities (FST = 0.085). Significant isolation by distance (IBD) was found for each country and when samples from both sides of the Andes range were pooled, although a lower correlation coefficient was observed. The Mantel test showed that the geographic distance and highest altitude of the mountains between locations were significantly associated with the pairwise FST when samples from both sides of the Andes range were pooled. According to a Bayesian assignment test (STRUCTURE), samples from Argentina and Chile conformed to two distinct genetic clusters. Our results also suggest that the recent invasion of C. pomonella in the southernmost localities (Aysén Region in Chile and Santa Cruz Province in Argentina) originated in populations from the respective sides of the Andes range. Our results indicate a genetic exchange of C. pomonella within each country and significant genetic differentiation between countries, which could be explained by dispersal mediated by human activities related to fruit production within each country with little exchange between them. A possible explanation is that the Andes range could be a significant barrier for dispersal by flight, and quarantine barriers could prevent the movement of plant material or infested fruit between countries. [ABSTRACT FROM AUTHOR]