Forest biodiversity conservation and species distribution modeling greatly benefit from broad‐scale forest maps depicting tree species or forest types rather than just presence and absence of forest, ...or coarse classifications. Ideally, such maps would stem from satellite image classification based on abundant field data for both model training and accuracy assessments, but such field data do not exist in many parts of the globe. However, different forest types and tree species differ in their vegetation phenology, offering an opportunity to map and characterize forests based on the seasonal dynamic of vegetation indices and auxiliary data. Our goal was to map and characterize forests based on both land surface phenology and climate patterns, defined here as forest phenoclusters. We applied our methodology in Argentina (2.8 million km2), which has a wide variety of forests, from rainforests to cold‐temperate forests. We calculated phenology measures after fitting a harmonic curve of the enhanced vegetation index (EVI) time series derived from 30‐m Sentinel 2 and Landsat 8 data from 2018–2019. For climate, we calculated land surface temperature (LST) from Band 10 of the thermal infrared sensor (TIRS) of Landsat 8, and precipitation from Worldclim (BIO12). We performed stratified X‐means cluster classifications followed by hierarchical clustering. The resulting clusters separated well into 54 forest phenoclusters with unique combinations of vegetation phenology and climate characteristics. The EVI 90th percentile was more important than our climate and other phenology measures in providing separability among different forest phenoclusters. Our results highlight the potential of combining remotely sensed phenology measures and climate data to improve broad‐scale forest mapping for different management and conservation goals, capturing functional rather than structural or compositional characteristics between and within tree species. Our approach results in classifications that go beyond simple forest–nonforest in areas where the lack of detailed ecological field data precludes tree species–level classifications, yet conservation needs are high. Our map of forest phenoclusters is a valuable tool for the assessment of natural resources, and the management of the environment at scales relevant for conservation actions.
Agricultural expansion and intensification has led globally to a rapid landscape structure change and high agrochemical use resulting in habitat loss and degraded environmental quality. Co-occurrence ...of landscape change and agrochemical contamination threatens biodiversity and might have interactive effects especially for organisms with complex life-cycles such as amphibians. We evaluated effects of landscape structure and agrochemical contamination at different spatial scales on anurans in Entre Rios, Argentina. We selected 35 independent stream headwaters along an agricultural expansion and intensification gradient. We conducted anuran call surveys from spring 2012 to summer 2013 and obtained detection-non detection data to estimate mean richness and focal species occupancy. We quantified forest area and riparian forest width at two spatial scales (sub-basin and local reach scale). We measured nutrients and pesticides in water and sediment. We evaluated anuran response to landscape and contamination variables using GLMs for richness and single season single-species occupancy models for focal species. Anuran diversity increased with forest area and riparian forest width, and decreased at sites with herbicide and nutrient contamination, particularly glyphosate; 2,4-D and nitrates. Also, most focal frog species responded mainly to basin forest and 2,4-D. Negative effects of agrochemical contamination on anuran diversity was mitigated in areas with larger basin forest cover. Agricultural management should ensure the reduction of herbicide and fertilizer use, the sparing of adequate forested habitat within drainage areas, and preservation of riparian forests around anuran breeding habitat to reduce and mitigate the negative effects of agrochemical contamination on anurans diversity in agroecosystems.
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•We studied agricultural expansion and intensification stressors on anuran diversity.•We used a landscape ecotoxicology approach at multiple spatial scales.•Herbicide-fertilizer contamination and forest loss at different scales reduce anuran diversity.•Forest loss and agrochemical contamination show interaction effects.•Greater forest cover within drainage area mitigates agrochemical contamination effects.
The Serrano Chaco forest is the least extended Gran Chaco forest type with a long history of human disturbances, such as ranching, urbanization, fires, an exotic tree species expansion, which have ...altered natural vegetation and, therefore, the resources available for avifauna. However, the impact of these disturbances on Serrano forest birds has received little attention. Here, using functional and taxonomic approaches, we explored the environmental, topographical and anthropogenic factors determining bird community structure in the Serrano forests at different spatial scales (< 250 m 500- and 1000-m). We used a combination of satellite imagery-based data and field sampling. We identified three ecological groups of birds: forest specialist, understory specialist and generalists, and classified them into functional groups according to life history traits and habitat use. We found that the response to landscape structure varied with the spatial scale and bird group; however, urban development and exotic trees forest occurrence were consistently present among the main factors reducing functional and taxonomic diversity of forest and understory birds. At the 1000-m scales, forest specialist birds tended to disappear from the areas with dense urbanization in areas with low percentage of Serrano forest. In landscape dominated by
L. lucidum
, forest understory birds tended to disappear. In all cases, generalist species expanded towards those areas. Our results indicate that the functional roles of avifauna are being greatly modified, potentially affecting forest ecosystem functioning. Restoration strategies must be implemented to preserve the last remnants of Serrano forest.
Aims
Wetlands are key ecosystems due to their economic, social and environmental contributions. Because of their highly productive habitats and their dependence on hydro‐meteorologic regimes, they ...are threatened worldwide by land use and climate change. In most wetlands, intensification of productive activities has been mostly accompanied by the implementation of a water management infrastructure, disrupting water and nutrient dynamics. Our aim was to analyze whether intensification of livestock raising erodes the structure and function of plant communities, as well as the quality and fertility of soils in wetlands.
Location
Non‐insular portion of the Lower Delta of the Paraná River, Argentina.
Methods
Plant communities were characterized on the basis of their floristic composition, structural and functional diversity. Soil samples were also collected to assess soil fertility, texture and quality. Generalized mixed linear models were used to contrast these attributes across livestock management practices characterized by differing water management infrastructure (polders and channelizations) and livestock type (bovine, bubaline).
Results
Remarkably fertile hydromorphic soils supported a structurally rich and functionally diverse species composition. Nevertheless, most dominant populations were terrestrial, perennial, invasive species, partially adapted to conditions of temporary flooding. Polderized livestock fields exhibited not only the lowest quality, least fertile, most compacted soils, but also lower species richness and diversity, as well as the lowest values in all non‐redundant components of functional diversity. Channelized livestock fields exhibited lower species richness and taxonomic diversity as well as reduced soil quality and fertility, yet an overall increase in most non‐redundant components of functional diversity.
Conclusions
Promoting the loss of native flora, water management infrastructure impairs the sustainability of anthropic activities and thwarts biodiversity conservation efforts. Traditional and sustainable practices that embrace the periodicity of the flood pulse are required to preserve the taxonomic and functional diversity of plant communities, as well as the quality and fertility of soils.
In the context of livestock raising intensification, fertile hydromorphic soils support structurally rich and functionally diverse plant communities. Water management infrastructures promote the disappearance and intensification of the flood pulse, disrupting plant species composition, as well as the quality and fertility of soils. A remarkable capacity of plant communities to preserve their structural and functional parameters was observed nonetheless.
Detailed maps of forest structure attributes are crucial for sustainable forest management, conservation, and forest ecosystem science at the landscape level. Mapping the structure of broad ...heterogeneous forests is challenging, but the integration of extensive field inventory plots with wall-to-wall metrics derived from synthetic aperture radar (SAR) and optical remote sensing offers a potential solution. Our goal was to map forest structure attributes (diameter at breast height, basal area, mean height, dominant height, wood volume and canopy cover) at 30-m resolution across the diverse 463,000 km2 of native forests of Argentina based on SAR Sentinel-1, vegetation metrics from Sentinel-2 and geographic coordinates. We modelled the forest structure attributes based on the latest national forest inventory, generated uncertainty maps, quantified the contribution of the predictors, and compared our height predictions with those from GEDI (Global Ecosystem Dynamics Investigation) and GFCH (Global Forest Canopy Height). We analyzed 3788 forest inventory plots (1000 m2 each) from Argentina's Second Native Forest Inventory (2015–2020) to develop predictive random forest regression models. From Sentinel-1, we included both VV (vertical transmitted and received) and VH (vertical transmitted and horizontal received) polarizations and calculated 1st and 2nd order textures within 3 × 3 pixels to match the size of the inventory plots. For Sentinel-2, we derived EVI (enhanced vegetation index), calculated DHIs (dynamic habitat indices (annual cumulative, minimum and variation) and the EVI median, then generated 1st and 2nd order textures within 3 × 3 pixels of these variables. Our models including metrics from Sentinel-1 and 2, plus latitude and longitude predicted forest structure attributes well with root mean square errors (RMSE) ranging from 23.8% to 70.3%. Mean and dominant height models had notably good performance presenting relatively low RMSE (24.5% and 23.8%, respectively). Metrics from VH polarization and longitude were overall the most important predictors, but optimal predictors differed among the different forest structure attributes. Height predictions (r = 0.89 and 0.85) outperformed those from GEDI (r = 0.81) and the GFCH (r = 0.66), suggesting that SAR Sentinel-1, DHIs from Sentinel-2 plus geographic coordinates provide great opportunities to map multiple forest structure attributes for large areas. Based on our models, we generated spatially-explicit maps of multiple forest structure attributes as well as uncertainty maps at 30-m spatial resolution for all Argentina's native forest areas in support of forest management and conservation planning across the country.
•Nationwide mapping of multiple forest structure attributes at 30-m resolution.•Uncertainty maps of each forest structure attribute at 30-m resolution.•Best predictors were a combination of Sentinel-1 and 2 data plus coordinates.•Forest height predictions outperformed those from GEDI and the GFCH.•Reliable predictions to support sustainable forest management in Argentina.
Land use is a key driver of the ongoing biodiversity crisis and therefore also a major opportunity for its mitigation. However, appropriately considering the diversity of land-use actors and ...activities in conservation assessments and planning is challenging. As a result, top-down conservation policy and planning are often criticized for a lack of contextual nuance widely acknowledged to be required for effective and just conservation action. To address these challenges, we have developed a conceptually consistent, scalable land system typology and demonstrated its usefulness for the world's tropical dry woodlands. Our typology identifies key land-use actors and activities that represent typical threats to biodiversity and opportunities for conservation action. We identified land systems in a hierarchical way, with a global level allowing for broad-scale planning and comparative work. Nested within it, a regionalized level provides social-ecological specificity and context. We showcase this regionalization for five hotspots of land-use change and biodiversity loss in dry woodlands in Argentina, Bolivia, Mozambique, India, and Cambodia. Unlike other approaches to present land use, our typology accounts for the complexity of overlapping land uses. This allows, for example, assessment of how conservation measures conflict with other land uses, understanding of the social-ecological co-benefits and trade-offs of area-based conservation, mapping of threats, or targeting area-based and actor-based conservation measures. Moreover, our framework enables cross-regional learning by revealing both commonalities and social-ecological differences, as we demonstrate here for the world's tropical dry woodlands. By bridging the gap between global, top-down, and regional, bottom-up initiatives, our framework enables more contextually appropriate sustainability planning across scales and more targeted and social-ecologically nuanced interventions.
Understanding the factors related to invasive exotic species distributions at broad spatial scales has important theoretical and management implications, because biological invasions are detrimental ...to many ecosystem functions and processes. Housing development facilitates invasions by disturbing land cover, introducing nonnative landscaping plants, and facilitating dispersal of propagules along roads. To evaluate relationships between housing and the distribution of invasive exotic plants, we asked (1) how strongly is housing associated with the spatial distribution of invasive exotic plants compared to other anthropogenic and environmental factors; (2) what type of housing pattern is related to the richness of invasive exotic plants; and (3) do invasive plants represent ecological traits associated with specific housing patterns? Using two types of regression analysis (best subset analysis and hierarchical partitioning analysis), we found that invasive exotic plant richness was equally or more strongly related to housing variables than to other human (e.g., mean income and roads) and environmental (e.g., topography and forest cover) variables at the county level across New England. Richness of invasive exotic plants was positively related to area of wildland-urban interface (WUI), low-density residential areas, change in number of housing units between 1940 and 2000, mean income, plant productivity (NDVI), and altitudinal range and rainfall; it was negatively related to forest area and connectivity. Plant life history traits were not strongly related to housing patterns. We expect the number of invasive exotic plants to increase as a result of future housing growth and suggest that housing development be considered a primary factor in plans to manage and monitor invasive exotic plant species.
Glossy privet (
Ligustrum lucidum
) is an aggressive invasive plant that replaces native forests and forms dense stands without understory in central Argentina. However, the consequences of these ...changes in terms of vegetation structure and composition in bird communities are unknown. Our goal was to understand how the effects of glossy privet invasion-induced habitat changes vary among bird species that differ in resource requirements (e.g., fruit supply, vegetation structure) and how these responses may in turn interact with the invasion process. We compared the avian–habitat relationships among forest patches with different invasion conditions (Serrano native forest, mixed forest and glossy privet forest) using a landscape approach. We found that bird richness was substantially lower in glossy privet forests, with up to 37% loss of bird species. Bird assemblages in invaded habitats changed, with an increase in the prevalence of bird species that feed on glossy privet, particularly during the cold season, when Serrano forest plants do not fruit. Our findings show that the loss of bird diversity and structural assemblage simplification were directly related to the loss of structural complexity caused by the invasion of glossy privet. The increased abundance of birds feeding on glossy privet contributed to the spread of this plant. Given the probable continued expansion of glossy privet and its resistance to control, the persistence of diverse native bird and plant communities in areas subject to invasion by this plant species is at risk.
Aim of study: To examine the transferability of G-SSR (genomic simple sequence repeats) and EST-SSR (expressed sequence tag simple sequence repeats) markers developed for several Neltuma species to ...N. affinis, a species with no genomic data. Area of study: West-Center of Entre Ríos province, Argentina. The set of molecular markers here proposed can be used to analyze samples from the entire species’ distribution range. Material and methods: Twenty-five genomic G-SSRs and eleven EST-SSRs from multiple species were amplified in thirty N. affinis genotypes. Polymorphism, discrimination power and possible deviations from Hardy-Weinberg equilibrium were assessed. Main results: Seventeen highly polymorphic G-SSRs were successfully transferred to N. affinis, with a PIC (polymorphic information content) average value of 0.811 and a He (expected heterozygosity) average value of 0.694; thirteen were validated, showing very low frequencies of null alleles and no linkage disequilibrium. Additionally, seven polymorphic EST-SSRs were transferred. As expected, PIC and He average values were low. Six out of seven markers were validated, and very low frequencies of null alleles and no linkage disequilibrium were observed. Research highlights: This work provides information on the levels of microsatellites’ cross transferability to N. affinis, and its polymorphism degree. Two sets of polymorphic SSRs (genomic and expressed) to study the genetic status of the species are proposed.
Wetlands loss has major consequences for biodiversity. The Delta of Paraná River is one of the largest wetland ecosystems in South America undergoing rapid conversion of freshwater marshes to ...pastures. We evaluated the response of nine wetland bird species to a gradient of landscape structure accounting for different levels of wetland loss in the Lower Delta, Argentina. We used point counts and a hierarchical distance sampling approach to assess the effects of wetland area, configuration, and land use on the density of species. Wetland area was the most important factor determining species density; most species responded positively at 100 m. The effect of wetland configuration varied among species; contiguous freshwater marsh area at 500 m only favored one species, whereas a large number of small patches of freshwater marsh benefited most species. Higher cattle density showed variable effects, and larger areas within polders reduced the density of two species. In the long term, wetland birds of the Lower Delta could decrease in density due to wetland loss and anthropogenic changes in the landscape. Our study shows the importance of considering the response of multiple species to landscape change at multiple scales and the need for a sustainable management of wetlands.
