Treesearch

Models project that climate change is increasing the frequency of severe storm events such as hurricanes. Hurricanes are an important driver of ecosystem structure and function in tropical coastal and island regions and thus impact tropical forest carbon (C) cycling. We used the DayCent model to explore the effects of increased hurricane frequency on humid tropical forest C stocks and fluxes at decadal and centennial timescales. The model was parameterized with empirical data from the Luquillo Experimental Forest (LEF), Puerto Rico. The DayCent model replicated the well-documented cyclical...

Tropical forests are a dominant regulator of the global carbon cycle, exchanging more carbon dioxide with the atmosphere than any other terrestrial biome. Climate models predict unprecedented climatic warming in tropical regions in the coming decades; however, in situ field warming studies are severely lacking in tropical forests. Here we present results from an in situ warming experiment in Puerto Rico, where soil respiration responses to +4 oC warming were assessed half-hourly for a year. Soil respiration rates were 42- 204% higher in warmed relative to ambient plots, representing some...

Understanding thermal stress in tropical forests has taken on new urgency in light of accelerating climate change and expansion of deforestation and forest degradation. Degraded tropical forests in particular may be approaching critical temperature thresholds even more rapidly than intact forests, with implications for tree survival and ecosystem recovery. We investigate thermal stress in degraded tropical forests within the Brazilian Amazon Arc of Deforestation. Using land surface temperature data from the ECOsystem Spaceborne Thermal Radiometer Experiment on the international Space...

We studied the stoichiometry of 6 forest stands dominated by Spathodea campanulata (African Tulip Tree; hereafter Spathodea) on alluvial (n = 3) and karst (n = 3) substrates in the north-central region of Puerto Rico. The stands were on lands previously used for Saccharum officinarum (Sugar Cane) cultivation, subsistence agriculture, and grazing, and are representative of novel forest emergence and secondary succession in the study region. The functioning of these novel forests is poorly understood, and we sought to improve our understanding by studying the stoichiometry of forest stands...

1. Long-term litterfall trends are unexplored in hurricane-prone regions but are needed to understand the consequences of altered hurricane regimes. In a wet tropical forest in northeastern Puerto Rico, we monitored litterfall mass (leaf fall, <2.5 cm diameter wood fall and miscellaneous), litterfall carbon (C) and nitrogen (N) and stream nitrate every 2 weeks for 29 years (1989–2017). 2. Litterfall from the nine observed hurricanes averaged 500 gm−2 hurricane−1 (CV = 90%), nearly half of the long-term mean of 951 gm−2 year−1. Hurricane generated leaf fall and wood fall increased with...

Global climate change phenomena are amplified in Arctic regions, driving rapid changes in the biota. Here, we examine changes in plant community structure over more than 30 years at two sites in arctic Alaska, USA, Imnavait Creek and Toolik Lake, to understand long-term trends in tundra response to changing climate. Vegetation cover was sampled every 4–7 years on permanent 1 m2 plots spanning a 1 km2 grid using a point-frame. The vascular plant canopies progressively closed at both locations. Canopy cover, defined here as an encounter of a vascular plant above the ground surface, increased...

The goal of the EcoVeg approach is to fully describe and classify the diversityof the Earth’s terrestrial ecosystems based on vegetation and ecological pro-cesses. The EcoVeg approach was used to develop the International VegetationClassification (IVC) and various national classifications, which integrate pat-terns of vegetation growth form, structure, and floristics with ecological andbiogeographic drivers at multiple spatial scales, from global formations to localplant communities. The approach remains unique among terrestrial ecologicalclassifications in providing types at these scales....

The agricultural and forestry sectors of the Caribbean are increasingly vulnerable to the challenges posed by climate change. Less predictable rainfall, more intense extreme climate events, and more days of extreme heat threaten crop and livestock productivity intensify pest and disease pressures, degrade soil health, and lead to significant social and economic challenges (Méndez-Lazaro et al. 2023; Gould et al. 2018). Although climate scenarios can help assess the detrimental implications of climate change in the Caribbean, substantial gaps persist in public knowledge regarding climate...

About 40% of the Brazilian Amazon has been deforested or suffered changes in forest structure through degradation (selective logging, fires, and fragmentation). The impact of forest degradation on the forest's sensitivity to climate extremes has not been fully explored because of a lack of data and the complex interplay of forest structure and climate drivers. Here, we combined forest structure data from 545 airborne lidar transects (375 ha each) across the Brazilian Amazon with the Ecosystem Demography Model (ED2). We explore the forest's functional response to near-present (1981–2019)...