Hotspots of biogeochemical activity linked to aridity and plant traits across global drylands.

Perennial plants create productive and biodiverse hotspots, known as fertile islands, beneath their canopies. These hotspots largely determine the structure and functioning of drylands worldwide. Despite their ubiquity, the factors controlling fertile islands under conditions of contrasting grazing by livestock, the most prevalent land use in drylands, remain virtually unknown. Here we evaluated the relative importance of grazing pressure and herbivore type, climate and plant functional traits on 24 soil physical and chemical attributes that represent proxies of key ecosystem services related to decomposition, soil fertility, and soil and water conservation. To do this, we conducted a standardized global survey of 288 plots at 88 sites in 25 countries worldwide. We show that aridity and plant traits are the major factors associated with the magnitude of plant effects on fertile islands in grazed drylands worldwide. Grazing pressure had little influence on the capacity of plants to support fertile islands. Taller and wider shrubs and grasses supported stronger island effects. Stable and functional soils tended to be linked to species-rich sites with taller plants. Together, our findings dispel the notion that grazing pressure or herbivore type are linked to the formation or intensification of fertile islands in drylands. Rather, our study suggests that changes in aridity, and processes that alter island identity and therefore plant traits, will have marked effects on how perennial plants support and maintain the functioning of drylands in a more arid and grazed world.

Bacterial Diversity in Old Hydrocarbon Polluted Sediments of Ecuadorian Amazon River Basins.

The Ecuadorian Amazon rainforest stands out as one of the world's most biodiverse regions, yet faces significant threats due to oil extraction activities dating back to the 1970s in the northeastern provinces. This research investigates the environmental and societal consequences of prolonged petroleum exploitation and oil spills in Ecuador's Amazon. Conducted in June 2015, the study involved a comprehensive analysis of freshwater sediment samples from 24 locations in the Rio Aguarico and Napo basins. Parameters such as water and air temperature, conductivity, soil pH, and hydrocarbon concentrations were examined. Total petroleum hydrocarbon (TPH) concentrations ranged from 9.4 to 847.4 mg kg-1, with polycyclic aromatic hydrocarbon (PAH) levels varying from 10.15 to 711.1 mg kg-1. The pristane/phytane ratio indicated historic hydrocarbon pollution in 8 of the 15 chemically analyzed sediments. Using non-culturable techniques (Illumina), bacterial analyses identified over 350 ASV, with prominent families including Comamonadaceae, Chitinophagaceae, Anaeromyxobacteraceae, Sphingomonadaceae, and Xanthobacteraceae. Bacterial diversity, assessed in eight samples, exhibited a positive correlation with PAH concentrations. The study provides insights into how microbial communities respond to varying levels of hydrocarbon pollution, shedding light on the enduring impact of oil exploitation in the Amazonian region. Its objective is to deepen our understanding of the environmental and human well-being in the affected area, underscoring the pressing need for remedial actions in the face of ongoing ecological challenges.

FunAndes - A functional trait database of Andean plants.

We introduce the FunAndes database, a compilation of functional trait data for the Andean flora spanning six countries. FunAndes contains data on 24 traits across 2,694 taxa, for a total of 105,466 entries. The database features plant-morphological attributes including growth form, and leaf, stem, and wood traits measured at the species or individual level, together with geographic metadata (i.e., coordinates and elevation). FunAndes follows the field names, trait descriptions and units of measurement of the TRY database. It is currently available in open access in the FIGSHARE data repository, and will be part of TRY's next release. Open access trait data from Andean plants will contribute to ecological research in the region, the most species rich terrestrial biodiversity hotspot.

Is the anemia in men an effect of the risk of crude oil contamination?

Pollution from oil spills can seriously affect many ecosystem processes and human health. Many articles have evaluated the impact of oil spills on human health. However, most of these articles focus on occupational exposure. The effect on people living in the areas affected by oil pollution is rarely studied. Approximately 640 million people worldwide live in areas at risk of oil pollution. Thus, studying the impact of this pollution on human health should be a priority. Here, we evaluate the presence of anemia in relation to crude oil exposure in men living in areas at risk of oil contamination in the Ecuadorian Amazon (Orellana and Napo). We evaluated the hematological and biochemical parameters of 135 participants. We divided the participants into three groups according to exposure: low, medium, and high. Our results showed a significant association between exposure risk and hemoglobin and hematocrit concentration. Groups with medium- and high- contamination exposure had levels below normal values in hemoglobin and hematocrit in more than 30% and 26% of the population, respectively. In conclusion, we found that crude oil affected human health, and the prevalence of the anemia in men was dependent of the level of contamination.

Amphibians of the equatorial seasonally dry forests of Ecuador and Peru.

Seasonally dry forests (SDFs) are one of the most challenging ecosystems for amphibians, fueling the diversity of this group of vertebrates. An updated inventory of native amphibians present in the Equatorial SDF is provided, which extends along the Pacific coast of Ecuador and northwestern Peru. The study is based on an extensive field sampling (two thirds of the total records) carried out throughout the Equatorial SDF, along with a compilation of the available information on distribution of amphibians in the region from published scientific papers, museum collections and on-line databases. The final dataset included 2,032 occurrence records for 30 amphibian species, belonging to eight anuran families. Additionally, data regarding conservation status, habitat use, spawn deposition site, reproductive mode, and body size, along with an identification key for all encountered species are provided. The results indicate a strong sampling bias with a deficit in the Peruvian part of the study area, and a need for urgent inventories targeted at under-sampled areas, using modern taxonomic methods. The study emphasizes the conservation priorities in the Equatorial SDF, based on the distribution, conservation status and life-history data. This information should be useful for the local authorities and institutions involved in the management and conservation of biodiversity in SDF.

Natural Regeneration in the Tumbesian Dry Forest: Identification of the Drivers Affecting Abundance and Diversity.

Tropical and subtropical dry forests make up the world's largest terrestrial ecosystem. However, these forests have been used to establish several productive activities, such as growing crops, rearing livestock, and using the forest resources, due to their ease of access and climatic conditions, which has led to this ecosystem becoming highly threatened. Therefore, this research assessed the effects of anthropogenic pressures and a number of abiotic variables on natural regeneration in dry forests in the Tumbesian region by addressing three research questions: (a) What is the status of natural regeneration in terms of abundance and diversity? (b) Does livestock grazing and the anthropogenic pressure affect the abundance and diversity of natural regeneration? (c) Does seasonality or grazing have the greatest influence on the regeneration dynamics? Data were obtained from 72 samples (36 fenced and 36 unfenced) during five surveys spanning a 2-year period, and the seedling abundance, mortality, recruitment, species richness and diversity were evaluated using linear mixed models. Natural regeneration was most positively affected by rainy season precipitation, but soil conditions also played an important role. Short-term fences had a major effect on reducing mortality but did not improve the abundance or diversity, whereas cattle grazing significantly affected the abundance of seedlings.

Pollen Resources Used by Two Species of Stingless Bees (Meliponini) in a Tropical Dry Forest of Southern Ecuador.

Pollinators are crucial for ecosystem functionality; however, little is known about the plant species used by some of these, such as stingless bees. In this study, for the first time, pollen resources used by Melipona mimetica Cockerell (Hymenoptera: Apidae: Meliponini) and Scaptotrigona sp. Moure (Hymenoptera: Apidae: Meliponini) were identified through analysis of corbicular pollen found on worker bees in a dry forest in southern Ecuador. In total, 68 pollen types were identified belonging to 31 botanical families. The most represented plant families were Fabaceae (16%), Malvaceae (7%), and Boraginaceae (7%). Both stingless bee species exhibited a polylectic behavior, with an average of 16 pollen types collected by individual bees. Differences in abundances of pollen types collected by each species indicated distinct uses for these two bee species.

Direct and indirect effects of plant and frugivore diversity on structural and functional components of fruit removal by birds.

Seed dispersal is an important ecosystem function, but it is contentious how structural and functional diversity of plant and bird communities are associated with seed-dispersal functions. We used structural equation models to test how structural (i.e., abundance, species richness) and functional diversity (i.e., functional dispersion and community-weighted means of functional traits) of fruiting plants and frugivorous birds directly and indirectly influence the respective components of fruit removal. We recorded plant and bird diversity in point counts and observed plant-frugivore interactions in a tropical mountain forest in Ecuador. We also recorded plant and bird morphological traits to calculate measures of functional diversity. We found that fruit abundance had a positive direct effect on bird abundance, which directly and indirectly mediated the abundance of removed fruits. Plant and bird species richness were only directly related to the richness of the removed fruits. Functional dispersion of the plant community was positively associated to that of the bird community and to that of the removed fruits. Consistently, we found positive associations between community-weighted means of plant and bird traits and between community-weighted means of plant traits and that of plants with removed fruits. In contrast, community-weighted means of the bird community were unrelated to that of the removed fruits. Overall, our results suggest that plant abundance directly and indirectly influences fruit removal, likely because of avian fruit tracking. However, we did not find strong links between the functional diversity of the frugivore community and removed fruits, suggesting that other factors in addition to plant-animal trait matching might be important for the functional diversity of removed fruits. Our findings highlight the importance of frugivore abundance for maintaining seed dispersal by animals in tropical forests.

Correction: Climate change versus deforestation: Implications for tree species distribution in the dry forests of southern Ecuador.

[This corrects the article DOI: 10.1371/journal.pone.0190092.].

Small-scale topography modulates elevational α-, ß- and γ-diversity of Andean leaf beetles.

Elevational diversity gradients are typically studied without considering the complex small-scale topography of large mountains, which generates habitats of strongly different environmental conditions within the same elevational zones. Here we analyzed the importance of small-scale topography for elevational diversity patterns of hyperdiverse tropical leaf beetles (Coleoptera: Chrysomelidae). We compared patterns of elevational diversity and species composition of beetles in two types of forests (on mountain ridges and in valleys) and analyzed whether differences in the rate of species turnover among forest habitats lead to shifts in patterns of elevational diversity when scaling up from the local study site to the elevational belt level. We sampled beetle assemblages at 36 sites in the Podocarpus National Park, Ecuador, which were equally distributed over two forest habitats and three elevational levels. DNA barcoding and Poisson tree processes modelling were used to delimitate putative species. On average, local leaf beetle diversity showed a clear hump-shaped pattern. However, only diversity in forests on mountain ridges peaked at mid-elevation, while beetle diversity in valleys was similarly high at low- and mid-elevation and only declined at highest elevations. A higher turnover of species assemblages at lower than at mid-elevations caused a shift from a hump-shaped diversity pattern found at the local level to a low-elevation plateau pattern (with similar species numbers at low and mid-elevation) at the elevational belt level. Our study reveals an important role of small-scale topography and spatial scale for the inference on gradients of elevational species diversity.

Climate change versus deforestation: Implications for tree species distribution in the dry forests of southern Ecuador.

Seasonally dry forests in the neotropics are heavily threatened by a combination of human disturbances and climate change; however, the severity of these threats is seldom contrasted. This study aims to quantify and compare the effects of deforestation and climate change on the natural spatial ranges of 17 characteristic tree species of southern Ecuador dry deciduous forests, which are heavily fragmented and support high levels of endemism as part of the Tumbesian ecoregion. We used 660 plant records to generate species distribution models and land-cover data to project species ranges for two time frames: a simulated deforestation scenario from 2008 to 2014 with native forest to anthropogenic land-use conversion, and an extreme climate change scenario (CCSM4.0, RCP 8.5) for 2050, which assumed zero change from human activities. To assess both potential threats, we compared the estimated annual rates of species loss (i.e., range shifts) affecting each species. Deforestation loss for all species averaged approximately 71 km2/year, while potential climate-attributed loss was almost 21 km2/year. Moreover, annual area loss rates due to deforestation were significantly higher than those attributed to climate-change (P < 0.01). However, projections into the future scenario show evidence of diverging displacement patterns, indicating the potential formation of novel ecosystems, which is consistent with other species assemblage predictions as result of climate change. Furthermore, we provide recommendations for management and conservation, prioritizing the most threatened species such as Albizia multiflora, Ceiba trichistandra, and Cochlospermum vitifolium.

Deforestation and Forest Fragmentation in South Ecuador since the 1970s - Losing a Hotspot of Biodiversity.

Deforestation and fragmentation are major components of global change; both are contributing to the rapid loss of tropical forest area with important implications for ecosystem functioning and biodiversity conservation. The forests of South Ecuador are a biological 'hotspot' due to their high diversity and endemism levels. We examined the deforestation and fragmentation patterns in this area of high conservation value using aerial photographs and Aster satellite scenes. The registered annual deforestation rates of 0.75% (1976-1989) and 2.86% (1989-2008) for two consecutive survey periods, the decreasing mean patch size and the increasing isolation of the forest fragments show that the area is under severe threat. Approximately 46% of South Ecuador's original forest cover had been converted by 2008 into pastures and other anthropogenic land cover types. We found that deforestation is more intense at lower elevations (premontane evergreen forest and shrubland) and that the deforestation front currently moves in upslope direction. Improved awareness of the spatial extent, dynamics and patterns of deforestation and forest fragmentation is urgently needed in biologically diverse areas like South Ecuador.