Aims We studied diversity, patterns of endemism and turnover of vegetation composition in dry inter-Andean valleys (DIAVs) where little is known about the influence of the abiotic drivers controlling plant species composition and occurrences, and the life forms that contribute most to α- and β-diversity, respectively. This study was focused on DIAVs located in the highlands (800–2800 m) around the Equator (1°N–5°S). The following questions were addressed: (i) what differences exist between endemic and non-endemic species in terms of species number, frequency and abundance? (ii) are patterns of α- and β-diversity correlated with latitude? (iii) what are the major environmental drivers controlling spatial patterns in species composition and occurrence? Methods We established 63 transects of 5 × 100 m in areas with DIAV vegetation, impacted as little as possible by human activities. In each transect, all mature trees and shrubs were identified and counted to determine their density. The coverage of terrestrial herbs was estimated. Generalized additive models were used to quantify the relationship between α- and β-diversity with latitude. To record α-diversity, we used the exponential Shannon index. The Sørensen index was used to measure β-diversity or species turnover. We used canonical correspondence analysis to determine species composition and generalized linear mixed models to quantify simultaneously the determinants of species occurrence across species and sites. The models were evaluated using the Akaike information criterion. All analyses were run separately for trees, herbs and shrubs.

Seasonally dry tropical forests are distributed across Latin America and the Caribbean and are highly threatened, with less than 10% of their original extent remaining in many countries. Using 835 inventories covering 4660 species of woody plants, we show marked floristic turnover among inventories and regions, which may be higher than in other neotropical biomes, such as savanna. Such high floristic turnover indicates that numerous conservation areas across many countries will be needed to protect the full diversity of tropical dry forests. Our results provide a scientific framework within which national decision-makers can contextualize the floristic significance of their dry forest at a regional and continental scale. Neotropical seasonally dry forest (dry forest) is a biome with a wide and fragmented distribution, found from Mexico to Argentina and throughout the Caribbean (1, 2) (Fig. 1). It is one of the most threatened tropical forests in the world (3), with less than 10% of its original extent remaining in many countries (4).

We investigate whether the Amotape—Huancabamba zone in the Andes acts as a barrier or corridor for plant species migration. We test this hypothesis based on data on trees, shrubs, and herbs collected in dry inter-Andean valleys (DIAVs) of Ecuador. We found that 72% of the species cross the Amotape—Huancabamba zone in a north—south direction and 13% of the species cross the Andes in an east—west direction. Southern DIAVs concentrate the highest numbers of endemic species. At the regional level we found that 43% of the species are exclusively Andean, while the remaining 57% are found in the Pacific lowlands, the Caribbean, and Mesoamerica. These results showing many species crossing the Amotape—Huancabamba zone in a north—south direction and also frequently found in neighboring lowland and highland ecosystems suggest that the Amotape—Huancabamba zone acts as a corridor for species migration of dry inter-Andean flora.

Los ecosistemas se¬cos son el punto de reunión de un gran número de especies que tienen una larga historia que contar; sobre cómo los ani¬males y plantas se resistieron a cam¬biar cuando los grandes colosos se levantaron e impusieron un nuevo régimen de humedad, temperatura y precipitación. Muchas familias botánicas fueron separadas unas de otras y tuvieron la oportunidad de diversificarse, llenando diversos nichos en el nuevo ecosistema. A los científicos les gusta darle a esta historia el nombre de evolución; di-lucidarla nos permite comprender la intrincada relación que existe entre los distintos miembros que constru¬yen la gran familia de la vida a lo largo del tiempo. Con estas pala¬bras queremos contar la historia de los bosques secos en el Ecuador, sus amenazas y estado de conservación, cómo es su diversidad y endemis¬mo a nivel regional, de manera que ayude a entender los procesos que los hacen ecosistemas “solitarios”, incluso cuando se encuentran ro¬deados por páramos, bosques mon¬tanos y amazónicos.

Background: Conserving both biodiversity and ecosystem services is a major goal of the Convention on Biological Diversity. Hotspots for biodiversity in the Andes significantly overlap with areas with dense human populations that sustain their economy through agricultural production. Therefore, developing management forms that reconcile food provisioning services—such as agriculture—with biodiversity conservation must be addressed to avoid social conflicts and to improve conservation in areas where biodiversity co-occurs with other ecosystem services. Here, we present a high-resolution conservation plan for vascular plants and agriculture in the Ecuadorian Dry Inter-Andean Valleys (DIAV) hotspot. Trade-offs in conserving important areas for both biodiversity and agriculture were explored. Methods: We used a dataset containing 5,685 presence records for 95 plant species occurring in DIAVs, of which 14 species were endemic. We developed habitat suitability maps for the 95 species using Maxent. Prioritization analyses were carried out using a conservation planning framework. We developed three conservation scenarios that selected important areas for: biodiversity only, agriculture only, and for both biodiversity and agriculture combined.

Understanding of tropical forests has been revolutionised by monitoring in permanent plots. Data from global plot networks have transformed our knowledge of forests’ diversity, function, contribution to global biogeochemical cycles, and sensitivity to climate change. Monitoring has thus far been concentrated in rain forests. Despite increasing appreciation of their threatened status, biodiversity, and importance to the global carbon cycle, monitoring in tropical dry forests is still in its infancy. We provide a protocol for permanent monitoring plots in tropical dry forests. Expanding monitoring into dry biomes is critical for overcoming the linked challenges of climate change, land use change, and the biodiversity crisis.