Considering the global intensification of aridity in tropical biomes due to climate change, we need to understand what shapes the distribution of drought sensitivity in tropical plants. We conducted a pantropical data synthesis representing 1117 species to test whether xylem-specific hydraulic conductivity (K S ), water potential at leaf turgor loss (Ψ TLP ) and water potential at 50% loss of K S (Ψ P50 ) varied along climate gradients. The Ψ TLP and Ψ P50 increased with climatic moisture only for evergreen species, but K S did not. Species with high Ψ TLP and Ψ P50 values were associated with both dry and wet environments. However, drought-deciduous species showed high Ψ TLP and Ψ P50 values regardless of water availability, whereas evergreen species only in wet environments. All three traits showed a weak phylogenetic signal and a short half-life. These results suggest strong environmental controls on trait variance, which in turn is modulated by leaf habit along climatic moisture gradients in the tropics.

Forest conservation and restoration are urgently needed to preserve key resources for the endemic fauna of dry southern Madagascar. This is a priority in the shrinking, seasonally dry forest of Berenty, a private reserve in Southern Madagascar. However, to provide a basis for forest restoration, a study of tree growth and regeneration in this unique biome is essential. A three-year planting program of native and endemic species was initiated in 2016. Three trial plots were established in forest gaps, with varying microclimates and soil conditions: one on the riverside, one in the mid-forest and the third in a degraded dryland area. We planted 1297 seedlings of 24 native tree species with plantings spaced at 1 m and 1.5 m and measured their height and stem diameters and recorded seedling mortality. We also recorded plant recruitment on the plots from the nearby forest. The main findings were that growth was best on the mid-forest plot planted at 1 m. Seedling mortality was highest on the riverside plot for the 1 m seedlings and least in the mid-forest at both planting distances. Recruitment was highest in the mid-forest at both planting distances and high also at 1.5 m by the river. These results are intended to aid future forest restoration on the Reserve and may serve as a reference for restoration of other dry forests in Madagascar. Finally, since species identification is central to the project, we collected, prepared and catalogued tree specimens to form a reference collection in an herbarium under construction in a new Research Centre at the reserve.

High biodiversity and endemism combined with persistently high deforestation rates mark Madagascar as one of the hottest biodiversity hot spots. Contemporary rising interest in large-scale reforestation, both globally and throughout Madagascar itself, presents a promising impetus for forest restoration and biodiversity conservation across the island. However, Madagascar may face unique restoration challenges due to its equally unique eco-evolutionary trajectory, which must be understood to enable successful ecological restoration. We conducted a systematic review of potential barriers to restoration for terrestrial forest biomes (rain forests, dry forests, and subhumid highland forests) in Madagascar. Our results indicate that aboveground biomass recovery of Malagasy forests appears to be slower than other tropical forests. We suggest four key synergistic factors that inhibit restoration in Madagascar: (a) lack of resilience to shifting nutrient and fire regimes arising from widespread high-intensity shifting cultivation; (b) predominance of nutrient-poor, highly weathered ferralitic soils; (c) vulnerability of regenerating native trees to competition with invasive species due to their evolutionary isolation; and (d) low seed dispersal into regenerating forests due to the unique dependence of Malagasy trees on dispersal by forest-dependent endangered or extinct primates. However, we note that rigorous experimental study of regenerating forests in Madagascar is currently lacking. There are great opportunity and need for such research to disentangle drivers and interactions inhibiting forest restoration. These studies would enable reforestation practitioners to effectively capitalize on current global momentum to implement the large-scale restoration necessary for the conservation of Madagascar's numerous endemic species.

La mayor parte de los estudios realizados hasta el momento sobre el complejo de páramos de Chingaza se han desarrollado principalmente en las zonas cercanas a Bogotá y algunos sectores del Parque Nacional Natural Chingaza. El objetivo del presente estudio fue caracterizar la zona de transición bosque-páramo en el complejo. Realizamos 5 transectos altitudinales en áreas con buen estado de conservación, en los que se obtuvieron 11,588 registros de ocurrencias y 1382 registros de rasgos funcionales de vegetación, edafofauna, anfibios y aves. Registramos dos especies de plantas en estado vulnerable (VU) (Hedyosmum parvifolium y Centronia brachycera) y un nuevo taxón endémico para este complejo de páramo (Puya loca). Análisis preliminares de los datos presentados sugieren variación en estructura biótica a lo largo del gradiente, y cambios en la composición de las comunidades. Con la información presentada se logró identificar la zona de transición entre el bosque altoandino y el páramo por medio de diversos atributos fisonómicos, florísticos, ecológicos y corológicos. Palabras clave. Alta montaña. Ecotono. Gradiente altitudinal. Norte de los Andes. Rasgo funcional.

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