Extreme drought events have negative effects on forest diversity and functioning. At the species level, however, these effects are still unclear, as species vary in their response to drought through specific functional trait combinations. We used long‐term demographic records of 21,821 trees and extensive databases of traits to understand the responses of 338 tropical dry forests tree species to ENSO2015, the driest event in decades in Northern South America. Functional differences between species were related to the hydraulic safety‐efficiency trade‐off, but unexpectedly, dominant species were characterised by high investment in leaf and wood tissues regardless of their leaf phenological habit. Despite broad functional trait combinations, tree mortality was more widespread in the functional space than tree growth, where less adapted species showed more negative net biomass balances. Our results suggest that if dry conditions increase in this ecosystem, ecological functionality and biomass gain would be reduced.

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Tropical dry forests (TDF) are known to be resource‐limited due to a marked seasonality in precipitation. However, TDF are also shaped by factors such as solar radiation, wind speed, soil fertility, and land‐cover transformation. Together, these factors may determine different gradients of environmental harshness that are likely to drive changes in plant community attributes. Here, we evaluated the effects of environmental harshness on plant community diversity and structure of Colombian TDF, based on floristic and environmental data from 15 1‐ha permanent plots. We also analyzed these effects on legumes species only (including both deciduous and non‐deciduous species), deciduous species only (including both legumes and non‐legumes species), and on the whole community excluding either legumes or deciduous separately. Drier conditions and higher land‐cover transformation had the strongest negative effects on species diversity, basal area (BA), and canopy height. Soil fertility, on the contrary, did not have a significant effect on any of the evaluated response variables. Interestingly, legumes maintained their diversity and BA along the climatic gradient, while deciduous species were negatively affected by drier conditions and by an increase in secondary vegetation at the landscape level. Our results suggest that although TDF are limited by water availability, land‐cover transformation strongly increases environmental harshness. Yet, both legumes and deciduous species were differentially impacted by climatic and land transformation variables. Thus, to better understand TDF plant community attributes, it is necessary to consider these gradients and to disentangle their effects on different plant functional groups. Abstract in Spanish is available with online material.

Societal Impact Statement Tropical dry forests (TDF) underpin the wellbeing of millions, mostly rural populations; yet have suffered from severe clearing in Colombia, triggering cascading effects such as desertification. By engaging scientists, society, and institutions in the establishment of platforms for monitoring biodiversity and ecosystem functioning, crucial knowledge gaps will be bridged, helping to find a path toward sustainable development. Science‐led but socially and economically anchored information on biodiversity will help to incorporate nature's contributions to people into the society's cultural values. Ultimately, these transformative actions will translate into the comprehensive management of TDF through a greater impact in decision making. Summary Thousands of permanent plots have been established across the tropics with the purpose of monitoring tree communities. Research outcomes from these platforms, however, have been mainly directed toward the academic community, and their contribution to society has been limited so far. Here, we show how generating robust data on biodiversity has supported decision making in Colombian tropical dry forests (TDF), where less than 8% of their original cover remains. As a first step to build a national dialogue around the critical status of this ecosystem, a national collaborative network on TDF research and monitoring was born in 2014, the Red de Investigación y Monitoreo del Bosque Seco Tropical en Colombia (Red BST‐Col). Our main goal is to generate scientifically sound information that feeds into the comprehensive management of this ecosystem. To do so, a set of biodiversity monitoring platforms has been established across the country, which have already served to answer socio‐ecological questions related with deforestation drivers, citizen science, or the valuation of ecosystem services. Overall, this research agenda has nurtured the four lines that underpin the Program for the comprehensive management of dry forests in Colombia (knowledge management, preservation, restoration, and sustainable use), formulated by the Humboldt Institute, the United Nations Development Programme, and the Ministry of Environment in 2019. Many challenges are ahead, however, for a complex territory where multiple social actors and productive sectors coexist. The ultimate goal is to integrate all the dimensions of biodiversity to achieve a synthetic understanding of the functioning of the most endangered ecosystem in Colombia, and its relationship with local communities' wellbeing.

A new species of sponge–dwelling snapping shrimp, Synalpheus amintae sp. nov. from the Parque Nacional Natural Isla Gorgona, Pacific coast of Colombia, is described. This new species pertains to the denominated Synalpheus “Gambarelloides” species group sensu Coutière (1909)—previously known as “Laevimanus” group. It was collected in the southern part of the Island, during episodes of extreme low tides, known locally as “puja”. Synalpheus amintae sp. nov. is closely related to the only two other known species of the S. “Gambarelloides” species group from the eastern Pacific: Synalpheus occidentalis Coutière, 1909, from Gulf of San José, Lower California, and Synalpheus mulegensis Ríos, 1992, from Bahía Concepción, Gulf of California, and can be differentiated from them by the poorly developed distal portion of pollex of the major cheliped, the armature of the distal segment of third maxilliped, and the number of acute teeth of exopodal uropod. A discriminative analysis dealing with other three species of Synalpheus from the western Atlantic, with distinctive pollex of major chela reduced, is presented. A dichotomous key was elaborated to identify the species of Synalpheus “Gambarelloides” species group from the eastern Pacific. The number of valid species described of Synalpheus from the eastern Pacific is increased to 23.