Expediciones Humboldt: Honda-Méndez, Tolima

Este informe presenta los resultados de la caracterización biológica de uno de los bosques secos con mejor estado de conservación en el departamento del Tolima, ubicado entre los municipio de Honda, Méndez y Armero-Guayabal. Estos bosques se encuentran en una matriz de ganadería y producción agropecuaria, donde las coberturas boscosas son conservadas por los propietarios, conscientes de la importancia de este ecosistema para la provisión de bienes y servicios ecosistémicos. Esperamos que esta información producto de la capacidad científica del Instituto Humboldt, sea relevante y útil en las decisiones de planificación estratégica tanto en el ordenamiento territorial de los municipios de Honda, Méndez y Armero-Guayabal, como para las decisiones de conservación que se tomen en la regiónBogotáCiencias Básicas de la Biodiversida

Biodiversity recovery of Neotropical secondary forests

Old-growth tropical forests harbor an immense diversity of tree species but are rapidly being cleared, while secondary forests that regrow on abandoned agricultural lands increase in extent. We assess how tree species richness and composition recover during secondary succession across gradients in environmental conditions and anthropogenic disturbance in an unprecedented multisite analysis for the Neotropics. Secondary forests recover remarkably fast in species richness but slowly in species composition. Secondary forests take a median time of five decades to recover the species richness of old-growth forest (80% recovery after 20 years) based on rarefaction analysis. Full recovery of species composition takes centuries (only 34% recovery after 20 years). A dual strategy that maintains both old-growth forests and species-rich secondary forests is therefore crucial for biodiversity conservation in human-modified tropical landscapes. Copyright © 2019 The Authors, some rights reserved

Change in terrestrial human footprint drives continued loss of intact ecosystems

Human pressure mapping is important for understanding humanity's role in shaping Earth's patterns and processes. Our ability to map this influence has evolved, thanks to powerful computing, Earth-observing satellites, and new bottom-up census and crowd-sourced data. Here, we provide the latest temporally inter-comparable maps of the terrestrial human footprint and assessment of change in human pressure at global, biome, and ecoregional scales. In 2013, 42% of terrestrial Earth could be considered relatively free of direct anthropogenic disturbance, and 25% could be classed as “wilderness” (the least degraded end of the human footprint spectrum). Between 2000 and 2013, 1.9 million km2—an area the size of Mexico—of land relatively free of human disturbance became highly modified. The majority of this occurred within tropical and subtropical grasslands, savannah, and shrubland ecosystems, but the rainforests of Southeast Asia also underwent rapid modification. Our results show that humanity's footprint is eroding Earth's last intact ecosystems, and greater efforts are urgently needed to retain them

Peace and the environment at the crossroads: Elections in a conflict-troubled biodiversity hotspot

In democracies around the world, societies have demonstrated that elections can have major consequences for the environment. In Colombia, the 2022 presidential elections will take place at a time when progress towards peace has stalled and socioeconomic, security, and environmental conditions have deteriorated. The recent declines in these conditions largely coincide with the change of government after the 2018 elections, and the associated rise to power of a party that boycotted the peace negotiations from the beginning. These indicators suggest that 2018 marked the end of a decade of improvements in safety, wealth, and equality-societal factors that can interact with the environment in multiple ways. A spike in assassinations of land and environmental defenders in 2019 and 2020 made Colombia one of the most dangerous places in the world for environmentalists. With the 2022 presidential election, Colombians will once again decide who will govern the country and what new social, economic, and environmental policies will be implemented. In preparation for elections like this, we believe that it is important for scientists with relevant backgrounds to highlight relationships between political events and the environment, to enrich the political debate, help prioritize public resources, and inform policymaking. Here, we provide a multidisciplinary analysis of different socioeconomic and environmental trends that can help inform the public and decision-makers. We intend for this analysis to be useful not only in Colombia, but also to other societies under similar situations, managing biodiversity-rich ecosystems in sociopolitical environments of increasing violence, poverty, and inequality

Multidimensional tropical forest recovery

Tropical forests disappear rapidly because of deforestation, yet they have the potential to regrow naturally on abandoned lands. We analyze how 12 forest attributes recover during secondary succession and how their recovery is interrelated using 77 sites across the tropics. Tropical forests are highly resilient to low-intensity land use; after 20 years, forest attributes attain 78% (33 to 100%) of their old-growth values. Recovery to 90% of old-growth values is fastest for soil (12 decades). Network analysis shows three independent clusters of attribute recovery, related to structure, species diversity, and species composition. Secondary forests should be embraced as a low-cost, natural solution for ecosystem restoration, climate change mitigation, and biodiversity conservation