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Effective vegetation classification schemes identify the processes determining species assemblages and support the management of protected areas. They can also provide a framework for ecological research. In the tropics, elevation-based classifications dominate over alternatives such as river catchments. Given the existence of floristic data for many localities, we ask how useful floristic data are for developing classification schemes in species-rich tropical landscapes and whether floristic data provide support for classification by river catchment. We analyzed the distribution of vascular plant species within 141 plots across an elevation gradient of 130 to 3200 m asl within La Amistad National Park. We tested the hypothesis that river catchment, combined with elevation, explains much of the variation in species composition. We found that annual mean temperature, elevation, and river catchment variables best explained the variation within local species communities. However, only plots in high-elevation oak forest and Paramo were distinct from those in lowand mid-elevation zones. Beta diversity did not significantly differ in plots grouped by elevation zones, except for low-elevation forest, although it did differ between river catchments. None of the analyses identified discrete vegetation assemblages within mid-elevation (700–2600 m asl) plots. Our analysis supports the hypothesis that river catchment can be an alternative means for classifying tropical forest assemblages in conservation settings.

Growth of high-elevation forests is generally temperature-limited and thus sensitive to warming. The Tibetan Plateau has experienced fast warming rates associated with decreased summer monsoon rainfall over the last century. However, whether such warming and monsoon-induced drought could offset a potential warming-driven enhancement of forest growth has not been examined. Here, we have compiled high-elevation forest growth data at 40 sites over the monsoonal Tibetan Plateau (MTP), and combined them in a high-elevation forest growth index (HEFGI) spanning 1567-2010. Tree growth in this region was significantly and positively correlated with July-October minimum temperatures during 1950-2010 (R2 = 0.53 P < 0.001), and insignificantly coherent with soil moisture and precipitation. The HEFGI of MTP reaches its highest values from the 2000s onwards. This result suggests that the mean HEFGI of MTP has not been negatively affected by the current drying trend and responded positively to increased temperatures.

Tree growth in high-elevation forests may increase as a result of increasing temperatures and CO2 concentrations in the atmosphere (Ca). However, the pattern and the physiological mechanism on how these two factors interact to affect tree growth are still poorly understood. Here, we analyzed the temporal changes in radial growth and tree-ring δ13C for Picea and Abies trees growing in both treeline and lower-elevation forests on the Tibetan Plateau. We found that the tree growth at the treeline has significantly accelerated during the past several decades but has remained largely stable or slightly declined at lower elevations. Further results based on tree-ring δ13C suggest that intrinsic water-use efficiency (iWUE) was generally higher at the treeline than in lower-elevation forests, although increasing trends of iWUE existed for all sites. This study demonstrated that the synergetic effects of elevated Ca and increasing temperatures have increased tree growth at the treeline but may not lead to enhanced tree growth in lower-elevation forests due to drought stress. These results demonstrate the elevational dependence of tree growth responses to climatic changes in high-elevation forests from a physiologically meaningful perspective.

Little information is available regarding red wood ant (RWA; Formica rufa group) impacts on soil carbon (C) and nitrogen (N) cycling in forest ecosystems. We found that RWA mound density (number per ha) was linked to forest tree species composition, slope aspect, and canopy closure. The size of RWA mounds was positively correlated with successional age of the stands. C and N concentrations of mound material were significantly higher than in the forest floor, while C:N ratios were not. RWA mound C and N pools were found to be significantly lower (< or =990 kg C/ha and < or = 21 kg N/ha) than in the forest floor. RWA mounds were \"hot spots\" for CO2 emissions ranging from 12.4 (mid July) to 3.5 (early September) times higher than the adjacent forest floor. Overall, they contributed 0.7-2.5% to total forest soil CO2 emissions. Consequently, the contribution of RWA to total forest soil C and N pools and forest CO2 emission is minor and likely not important when calculating or modeling C and N pools or C fluxes. Yet, RWAs increase the spatial heterogeneity of soil C and nutrients and alter the flow of energy within their habitat.

The Central Himalayas, characterized by one of the most pronounced elevation gradients globally, harbor forest stands of high carbon density. With estimated forest aboveground biomass (AGB) densities of up to 1000 t ha −1 , these forests are among the most carbon-rich ecosystems within the Himalayas and high mountain ranges globally. However, existing global and regional models of forest carbon distribution fail to accurately capture the remarkable carbon density observed in these Himalayan forest stands. Our objective was to quantify how fine-scale topoclimatic conditions influence the spatial variability of AGB, with the aim of identifying the environmental factors that contribute to the high carbon density observed in high mountain forests of Nepal. Our analysis focused on quantifying the contribution of terrain-driven variation in climatic energy and water availability in creating favourable site conditions for carbon-dense forests. We found that extreme forest carbon density is associated with distinct topographic settings related to slope, aspect and curvature that provide a combination of adequate levels of both climatic energy and water availability, while forest carbon was reduced in topographic positions associated with high likelihood of disturbance such as avalanches and mass movements. Our findings shed light on the intricate relationship between topoclimatic factors and conditions for carbon storage in high-elevation forests, providing valuable insights for conservation and management strategies in mountainous regions.

The characterization of modern pollen rain assemblages along environmental gradients is an essential prerequisite for reliable interpretations of fossil pollen records. In this study, we identify pollen-vegetation relationships using modern pollen rain assemblages in moss polsters (n = 13) and lake sediment surface samples (n = 11) along a steep temperature gradient of 7°C (3100–4200 m above sea level) on the western Andean Cordillera, Ecuador. The pollen rain is correlated to vascular plant abundance data recorded in vegetation relevées (n = 13). Results show that pollen spectra from both moss polsters and sediment surface samples reflect changes in species composition along the temperature gradient, despite overrepresentation of upper montane forest taxa in the latter. Estimated pollen transport distance for a lake (Laguna Llaviucu) situated in a steep upper montane forest valley is 1–2 km, while a lake (Laguna Pallcacocha) in the páramo captures pollen input from a distance of up to 10–40 km. Weinmannia spp., Podocarpus spp., and Hedyosmum sp. are indicators of local upper montane forest vegetation, while Phlegmariurus spp. and Plantago spp. are indicators for local páramo vegetation.

Afforestations provide cost-effective and environmentally friendly protection against natural hazards, compared to technical measures. In Austria, more than 3000 afforestation sites for hazard protection covering 9000 ha have been established between 1906 and 2017, mainly for snow avalanche protection. The actual protective effect depends on avalanche predisposing factors and land cover, i.e. whether forest is present. In this study, predisposing factors and land cover classes were identified and analysed in selected afforestation sites. The protective effect of forest was attributed to the presence of forest cover and tree species. Using RGB images with a ground resolution of 20 × 20 cm, nine land cover categories have been distinguished by means of supervised classification with the random forest algorithm. Those land cover categories were classified with an overall accuracy of 0.87–0.98 and Kappa-values, ranging between 0.81 and 0.93. Images were filtered using a 3 pixel by 3 pixel majority filter, which assigns each cell in the output grid the most commonly occurring value in a moving window centred on each grid cell. This filter further increased the overall accuracy by removing noise pixels while preserving the fine elements of the classified grid. Our results indicate a protective effect for about half of the analysed afforestation sites. The dominance of the land use class “Meadow” at most sites with little avalanche protection effect suggests grazing as a limiting factor. The spatial information provided with the described method allows to identify critical areas in terms of avalanche protection even years after the initial afforestation.

Ecosystems that provide environmental opportunities but are poor in species and functional richness generally support speciation as well as invasion processes. These processes are expected not to be equally effective along elevational gradients due to specific ecological, spatial, and anthropogenic filters, thus controlling the dispersal and establishment of species. Here, we investigate speciation and invasion processes along elevational gradients. We assess the vascular plant species richness as well as the number and percentage of endemic species and non‐native species systematically along three elevational gradients covering large parts of the climatic range of La Palma, Canary Islands. Species richness was negatively correlated with elevation, while the percentage of Canary endemic species showed a positive relationship. However, the percentage of Canary–Madeira endemics did not show a relationship with elevation. Non‐native species richness (indicating invasion) peaked at 500 m elevation and showed a consistent decline until about 1,200 m elevation. Above that limit, no non‐native species were present in the studied elevational gradients. Ecological, anthropogenic, and spatial filters control richness, diversification, and invasion with elevation. With increase in elevation, richness decreases due to species–area relationships. Ecological limitations of native ruderal species related to anthropogenic pressure are in line with the absence of non‐native species from high elevations indicating directional ecological filtering. Increase in ecological isolation with elevation drives diversification and thus increased percentages of Canary endemics. The best preserved eastern transect, including mature laurel forests, is an exception. The high percentage of Canary–Madeira endemics indicates the cloud forest's environmental uniqueness—and thus ecological isolation—beyond the Macaronesian islands. Ecological, anthropogenic, and spatial filters control plant richness, diversification, and establishment of non‐native species on the oceanic island La Palma. Increase in ecological isolation with elevation likely drives diversification and thus above average numbers of endemics at high elevations. We argue that unsuitable environmental conditions and lower human influences are responsible for the absence of non‐native species at elevations above 1200 m.

Life-history traits have been described disproportionately for temperate-breeding birds. Efforts to conserve global biodiversity require a more holistic understanding of avian life-history theory across biomes and geographic locations. In this account, we present the first detailed description of the breeding biology of the Bornean Stubtail (Urosphena whiteheadi). We discuss the stubtail's breeding strategies in the context of life-history theory and contrast them with those of 4 other members of the same family breeding at higher latitudes and lower elevations. The Bornean Stubtail is a tropical montane passerine belonging to the Old World Cettiidae family and endemic to the island of Borneo. Compared to other Cettiidae warblers, the Bornean Stubtail has a small clutch of 2 eggs and a long incubation period of 23.0 ± 0.10 d. At our site, their open-cup nests were constructed of moss and placed on or near the ground on vertical features in rainforest understory. The nests experienced a daily survival rate of 0.939 ± 0.006 and daily predation rate of 0.054 ± 0.006. Mean fresh egg mass was 1.87 ± 0.012 g. Egg-laying began in mid-February and continued into May. The number of active nests increased until mid-March at which point it remained relatively consistent until mid-May when it began to taper off. Nest attentiveness during incubation was low with a very long off-bout of ∼7 h every day that decreased to ∼4 h later in incubation, explaining the species' long incubation period. In contrast, nestling provisioning rates increased steadily over the nestling period (mean 12.53 ± 0.24). Nestling growth followed a logistic trend commonly seen in passerines, and near-adult sizes were reached by fledging. Rasgos de historia de vida han sido descritos desproporcionalmente en aves de reproducción en sitios templados. Los esfuerzos de conservación de la biodiversidad global requieren un entendimiento más holístico de las teorías de historias de vida a través de distintos biomas y localidades geográficas. Por ello, presentamos la primera descripción detallada de la biología reproductiva de la buscarla-colicorta Urosphena whiteheadi. Discutimos las estrategias reproductivas de la colicorta en el contexto de la teoría de historias de vida y las contrastamos con otros 4 miembros de esa familia que se reproducen en grandes alturas y elevaciones más bajas. La buscarla-colicorta Urosphena whiteheadi es un ave paserina de montaña tropical que pertenece a la familia Cettidae del Viejo Mundo y que es endémica de la isla de Borneo. Comparada con otras buscarlas-colicortas de la familia Cetiidae, la buscarla-colicorta Urosphena whiteheadi tiene unas puestas pequeñas de 2 huevos y un periodo largo de incubación de 23 ± 0.1 días. En nuestro sitio, los nidos de copa abierta fueron construidos con musgo y colocados en o cerca del suelo en elementos verticales en el sotobosque forestal. Los nidos experimentaron una tasa diaria de supervivencia de 0.939 ± 0.006 y una depredación diaria de 0.054 ± 0.006. La masa promedio de huevos fue de 1.87 ± 0.012 g. La puesta de huevos inició a mediados de febrero y continuó hasta mayo. El número de nidos activos aumentó hasta mediados de marzo, luego se mantuvo relativamente contante hasta mediados de mayo cuando empezó a disminuir. La atención al nido durante la incubación fue baja con largos periodos de ausencia ∼7 h cada día que luego disminuyeron a ∼4 h posteriormente durante la incubación, lo que explica el largo periodo de incubación de la especie. En contraste, las tasas de aprovisionamiento del nido aumentaron constantemente durante el periodo de incubación (promedio 12.53 ± 0.24). El crecimiento del polluelo siguió una tendencia logística típicamente vista en aves paserinas y tallas cercanas a las de adulto fueron alcanzadas por los volantones. Palabras clave: ave paserina de bosque tropical, cambio climático, conteo de especies, grandes alturas, historia de vida, periodo de incubación, tamaño de puesta.

The two major rainforests of the neotropics, the Amazon and Atlantic forests, show maximum expansion during the warm and wet conditions of interglacial periods, including the current Holocene. They are connected by a network of gallery forests through the Cerrado biome. However, the extent of their expansion during glacial periods, when they were more disjunct, is unknown. During glacial periods, a pollen assemblage comprising Podocarpus–Ilex–Hedyosmum–Myrsine displays higher frequencies in marine, continental and coastal Brazilian pollen records. This assemblage is observed today in the high-elevation grasslands of the Cerrado and Atlantic Forest biomes and in the coastal vegetation, the restinga, of southern Brazil. We therefore reviewed the possible migration routes for these species by tracking glacial period Podocarpus–Ilex–Hedyosmum–Myrsine assemblages in published pollen records. The marine pollen records provide evidence of a glacial expansion of restinga, its floristic composition being continuous with the dominant regional vegetation, a cold type of shrubby grassland. There appear to be two migration routes, one involving the expansion of high-elevation grassland taxa within the lowlands, and the other low-sea level stands of coastal restinga. We conclude that the Cerrado was a node of migration between the Amazon and Atlantic rainforests, linking the Andes to the central and coastal mountains of Brazil. The Brazilian mountain ranges represent refugia of ancient taxa that colonized the continent up to the Andes and modified the floristic composition of the two rainforests during the Pleistocene glacial periods.