ForestGEO

The bobcat (Lynx Rufus Schreber, 1777) is a mesopredator distributed from southern Canada to southern Mexico. Its presence is an indicator of good ecosystem quality. Although it is considered the most abundant felid in Mexico, there are very few studies that evaluate its population dynamics in arid zones. Therefore, the objective was to determine the population density and occupancy probability of bobcats in fragments of Tamaulipan thornscrub. Population abundance and density were estimated using camera traps and the MARK-CAPTURE tool. The vegetation composition of landscape corridors was evaluated to estimate their relationship with the bobcat population. An occupancy model was elaborated to analyze the presence of the species in the area, using environmental and anthropogenic impact covariates. The average density resulted in 8 individuals 100 km-2, derived from the identification of 23 bobcats and an effective sampling area of 140.31 km2. Sites 17 and 18 had the highest vegetation cover and the highest number of records, as well as a female with cubs and with different prey. The occupancy probability was positively associated with areas of higher vegetation cover. It is concluded that the density values presented are associated with the fragmentation of the vegetation community, and that the variables with the greatest influence on the presence of bobcats are vegetation cover and diversity.

Understanding the drivers of aboveground wood productivity (AWP) in tropical forests is crucial for explaining ecosystem functioning and predicting their responses to environmental change. While climatic water availability is a well-established driver, the role of soil nutrients and their interaction with other resources remains uncertain. We investigated how soil nutrients and light interactions shape AWP in lowland tropical forests using fine-scale soil and tree (≥ 1 cm DBH) data from 15 large forest plots. Canopy-exposed trees are nutrient-limited, with AWP increasing more with phosphorus (P) than with potassium (K), indicating P's greater role in plant growth and productivity. Conversely, understory AWP declined in fertile areas, likely due to intensified size-asymmetric competition. At the population level (mean across canopy layers), no relationship between soil nutrients and AWP emerged because contrasting responses among layers offset any overall association. Our results suggest that fine-scale heterogeneity and canopy stratification drive nutrient effects on tropical forest productivity.

Abstract Studies can only guide conservation if their findings are informative at the scales at which practitioners and policymakers operate. Yet, it is rarely tested whether large-scale studies reach similar conclusions to the smaller-scale studies on which conservation traditionally relies. We examine whether predictors of extinction risk are consistent across global, regional, and local scales, for 210 tropical forest mammal species (≥ 1 kg) that existed during the last 130,000 years, in 64 tropical forests, across three biogeographical realms. We found consistent predictors of extinction risk (body mass, generation length, diet, brain volume and scansoriality) when analyses differed only in their spatial resolution. However, predictors differed when analyses also varied in their temporal extent. Macroecological findings about extinction risk can, thus, inform conservation at smaller scales, but they risk misidentifying threatened species if differences in temporal extent are not recognised.

<strong class="journal-contentHeaderColor">Abstract.</strong> Accurate assessment of leaf functional traits is crucial for a diverse range of applications from crop phenotyping to parameterizing global climate models. Leaf reflectance spectroscopy offers a promising avenue to advance ecological and of robust hyperspectral models for predicting leaf photosynthetic capacity and associated traits from reflectance data has been hindered by limited data availability across species and environments. Here we introduce the Global Spectra-Trait Initiative (GSTI), a collaborative repository of paired leaf hyperspectral and gas exchange measurements from diverse ecosystems. The GSTI repository currently encompasses over 7500 observations from 397 species and 41 sites gathered from 36 published and unpublished studies, thereby offering a key resource for developing and validating hyperspectral models of leaf photosynthetic agricultural research by complementing traditional, time-consuming gas exchange measurements. However, the development capacity. The GSTI database is developed on GitHub (<a href="https://github.com/plantphys/gsti" target="_blank" rel="noopener">https://github.com/plantphys/gsti</a>) and published to ESS-dive <a href="https://data.ess-dive.lbl.gov/datasets/doi:10.15485/2530733" target="_blank" rel="noopener">https://data.ess-dive.lbl.gov/datasets/doi:10.15485/2530733</a>, Lamour et al., 2025). It includes gas exchange data, derived photosynthetic parameters, and key leaf traits often associated with traditional gas exchange measurements such as leaf mass per area and leaf elemental composition. By providing a standardized repository for data sharing and analysis, we present a critical step towards creating hyperspectral models for predicting photosynthetic traits and associated leaf traits for terrestrial plants.

Abstract The vertical gradient of light in closed‐canopy forests selects for trees with different adult statures, but our understanding of how stature affects forest diversity and demography is unclear. In a species‐rich rainforest in Cameroon, we quantified the contributions of four growth forms of increasing adult stature (treelet, understory, canopy, emergent species) to forest structure and diversity, and investigated variation in life history trade‐offs across growth forms. Treelets had the highest stem density, contributed the most to forest diversity, and diverged from larger statured species in terms of demographic trade‐offs. Growth rates were slower for smaller statured than for larger statured species, and at the adult stage, treelets had significantly lower mortality than other growth forms. We observed significant interspecific trade‐off relationships between staure and demographic rates that often differed between growth forms. Recruitment rate strongly declined with adult stature for all growth forms, but recruitment per reproductive adult declined only for emergents. While we observed a significant growth‐mortality trade‐off across all species, the trade‐off was similar across growth forms. Smaller statured species in our study are not light‐demanding but rather treelet and understory species that live entirely in the shaded understory. Differences in how historical biogeography has shaped species pools may ultimately cause variation in how adult stature contributes to tropical forest diversity.

Increasing tree species diversity in Mediterranean forests could reduce drought-induced hydraulic impairments through improved microclimate and reduced competition for water. However, it remains unclear if and how species diversity modulates tree hydraulic functions and how impacts may shift during the growing season. Using unmanaged Mediterranean forest stands composed of one (i.e., monospecific) or four (i.e., multispecific) tree species, we examined the seasonal dynamics of in-situ hydraulic traits (predawn and midday leaf water potential - Ψpd and Ψmd, xylem- and leaf-specific hydraulic conductivity - KS and KL, percentage loss of conductivity - PLC, specific leaf area - SLA, and Huber value - HV) in four co-existing Pinus and Quercus species over two years. We mainly observed adverse impacts of species diversity with lower Ψpd, Ψmd, KS, KL, and higher PLC in multispecific compared to monospecific stands, especially for the two pines. These impacts were observed all along the growing season but were stronger duringthe driest periods of the summer. Beneficial impacts of diversity were rare and only occured for oaks (Q. faginea) after prolonged and intense water stress. Our findings reveal that mixing oaks and pines could mainly enhance hydraulic impairments for all species during the dry season, suggesting a potential decline in mixed Mediterranean forests under future climate.

Heatwaves and soil droughts are increasing in frequency and intensity, leading many tree species to exceed their thermal thresholds, and driving wide-scale forest mortality. Therefore, investigating heat tolerance and canopy temperature regulation mechanisms is essential to understanding and predicting tree vulnerability to hot droughts. We measured the diurnal and seasonal variation in leaf water potential (Ψ), gas exchange (photosynthesis Anet and stomatal conductance gs), canopy temperature (Tcan), and heat tolerance (leaf critical temperature Tcrit and thermal safety margins TSM, i.e., the difference between maximum Tcan and Tcrit) in three oak species in forests along a latitudinal gradient (Quercus petraea in Switzerland, Quercus ilex in France, and Quercus coccifera in Spain) throughout the growing season. Gas exchange and Ψ of all species were strongly reduced by increased air temperature (Tair) and soil drying, resulting in stomatal closure and inhibition of photosynthesis in Q. ilex and Q. coccifera when Tair surpassed 30°C and soil moisture dropped below 14%. Across all seasons, Tcan was mainly above Tair but increased strongly (up to 10°C > Tair) when Anet was null or negative. Although trees endured extreme Tair (up to 42°C), positive TSM were maintained during the growing season due to high Tcrit in all species (average Tcrit of 54.7°C) and possibly stomatal decoupling (i.e., Anet ≤0 while gs >0). Indeed, Q. ilex and Q. coccifera trees maintained low but positive gs (despite null Anet), decreasing Ψ passed embolism thresholds. This may have prevented Tcan from rising above Tcrit during extreme heat. Overall, our work highlighted that the mechanisms behind heat tolerance and leaf temperature regulation in oak trees include a combination of high evaporative cooling, large heat tolerance limits, and stomatal decoupling. These processes must be considered to accurately predict plant damages, survival, and mortality during extreme heatwaves.

The relative importance of abiotic and biotic factors in shaping forest biomass stocks and fluxes remains a controversial issue. Here, using data gathered from 39 1 ha plots located in flooded and terra firme mature tropical lowland forests of the Amazon and Orinoquia regions of Colombia, we evaluated the importance of climate, soil fertility, and flooding, as well as tree taxonomic/phylogenetic diversity and forest structural properties, in determining the aboveground biomass stocks (AGB; Mg ha −1 ) and aboveground woody productivity (AWP; Mg ha −1 year −1 ). Using information‐theoretic multimodel inference and variance partitioning we found that forest structural features such as the number of trees with diameter at breast height ≥ 70 cm, and wood density, are the main drivers of variation in AGB. However, taxonomic diversity also contributes to AGB because it is associated with more large trees in these forests. In contrast, the key drivers of AWP in these forests were soil P and Mg concentrations, with no significant effects of diversity indices. These findings emphasize the need to include major soil cations other than N and P (e.g. Mg) in experimental studies to improve our understanding about the extent to which soil fertility can modulate increases in forest AWP due to climate change. Terra firme forests had higher AGB stocks than flooded forests, but both had similar AWP; and we found similar results for the drivers of AGB and AWP between flooded and terra firme forests. Our results provide limited evidence for strong effects of plant diversity on AGB or AWP. Therefore, we call for caution on generalizations of nature‐based initiatives aiming to preserve diversity based on maximizing carbon stocks and productivity, due to the complex nature of the processes controlling carbon accumulation and carbon fluxes in tropical forests.

Restoration of forests in low- and middle-income countries (LMICs) has the potential to contribute to international carbon mitigation targets. However, high upfront costs and variable cashflows are obstacles for many landholders. Carbon payments have been promoted as a mechanism to incentivize restoration and economists have suggested cost-sharing by third parties to reduce financial burdens of restoration. Yet empirical evidence to support this theory, based on robust, dynamic field sampling is lacking. Here we use large, long-term datasets from Panama to evaluate the financial prospects of three forest restoration methods under different cost-sharing and carbon payment designs where income is generated through timber harvests. We show some, but not all options are economically viable. Further work combining growth and survival data from field trials with more sophisticated financial analyses is essential to understanding barriers and realizing the potential of forest restoration in LMICs to help meet global carbon mitigation commitments.