Biodiversity Conservation Strategies Research Articles

Is a Fishing Moratorium Needed in Lake Honghu, Southern China? A Stomach Content Analysis of the Anchovy (Coilia brachygnathus)

Since 2017, a fishing moratorium has been enforced in Lake Honghu as part of Chang–Jiang’s biodiversity conservation strategy. However, given that the lake is a semi-closed aquatic ecosystem and no longer serves as a habitat for certain fishes of the mid–lower Chang–Jiang basin, the efficacy of this moratorium remains uncertain. To address the question from a trophic ecology perspective, a stomach content analysis was performed on captured anchovies of C. brachygnathus, a current predominant species in Lake Honghu, from November 2020 to October 2021. The results showed that copepods, shrimps, and macrophytes were the main components of this anchovy’s diet, and there were size-related shifts in diets. The dominance of C. brachygnathus, a pelagic–littoral omnivore in this lake, implies a lacustrine environment shift triggered by continued human disturbances. The utilization of macrophytes as the main food items by large-sized anchovies of Lake Honghu has partially contributed to the rapid degradation of submerged vegetation. This highlights the need to remove large-sized individuals of C. brachygnathus and Carassius auratus, another benthic-omnivorous dominant fish, in order to effectively restore the aquatic vegetation and ecosystem of Lake Honghu. The current implementation of fishing moratoriums in subtropical shallow floodplain lakes such as Lake Honghu should be reviewed critically.

From small waterbodies to large multi-service providers: Assessing their ecological multifunctionality for terrestrial birds in Mediterranean agroecosystems

Agricultural intensification has caused a rapid loss of singular landscape elements worldwide, such as farmland ponds, hedgerows and field margins, leading to a steep decline in farmland bird populations. Farmland ponds and traditional small waterbodies (SWB) have been recently reported to support species-rich bird communities at landscape scale in several agroecosystems. However, a comprehensive assessment on the potential ecological functions provided by SWB to terrestrial birds has been never conducted. Here, we used data from breeding bird surveys at 39 traditional SWB to highlight the variety and magnitude of ecological functions provided to terrestrial birds. These SWB belonged to three different structural types and were spread along an environmental gradient in Mediterranean agroecosystems from southeastern Spain. We identified up to six cross-system services benefiting different functional guilds of terrestrial birds. Apart from to the well-documented supply of drinking water, traditional SWB delivered other ecologically relevant and commonly overlooked services to terrestrial birds, such as the provision of bathing sites, essential food resources (e.g., emerging insects), nest-building material and suitable adjacent perches for territorial display or thermoregulation. Structural and environmental variables at waterbody scale played an important role as determinants of the recorded ecological functions. Importantly, most of these ecological functions were evenly observed across the three types of traditional SWB, thus supporting the key role of these singular landscape elements for bird conservation regardless their structural attributes. Agri-environment schemes and farmland biodiversity conservation strategies should account for the ecological multifunctionality of traditional SWB by ensuring the protection and nature-friendly management of these valuable habitats, as well as by promoting the diversity of microhabitats at SWB scale.

Anthropogenic activities explained the difference in exotic plants invasion between protected and non-protected areas at a northern subtropics biodiversity hotspot

Biological invasion poses a major threat to biodiversity and conservation efforts in protected areas. The Greater Shennongjia Area (GSA) is one of China's 16 key areas for biodiversity, as stated in the China National Biodiversity Conservation Strategy and Action Plan. However, the local authorities lack appropriate data on the extent and impact of exotic species in protected areas, as well as lack the capacity and motivation to properly plan for exotic species strategy and action plan to support both prevention, control as well as management of exotic plants in their jurisdiction. In addition, while most previous studies have focused on exotic species in protected areas, little effort has been devoted to specifying which environmental factors contribute to the difference between protected and non-protected areas. Here, we explored the current distribution pattern of the richness and abundance of exotic species in relation to environmental variables within the GSA. In total, we found 84 exotic plant species, of which 41 exotic species within the protected areas, in 64 genera and 27 families, predominately from Asteraceae, Fabaceae, and Poaceae. The generalized linear mixed models (GLMMs) revealed that the protection status and the distance to human settlements were the most important predictors of exotic plant richness and abundance in the GSA. Our results showed that the average exotic plant richness and coverage in the protected areas were 22% and 31% lower than outside the protected areas, respectively. Such differences were probably the result of anthropogenic activities (e.g., proximity to human settlements and the proportion of cropland). Although protected areas provide an important barrier against plant invasions, invasion may be a tricky issue for protected area management in the future. The Alliance of Protected areas in Western Hubei and Eastern Chongqing will need to further consider stringent control and management strategies for the entry of exotic species into protected areas to effectively maintain the continuity and integrity of the GSA's biodiversity and ecosystems. Our results provided guidance and support to enhance the capacity of scientific and effective management and sustainable development of the Shennongjia World Natural Heritage Site and other protected areas.

Conservation implications of tourism and stress for Amazonian caimans

AbstractEcotourism is a strategy for biodiversity conservation, but it involves possible negative effects on animal health and welfare. Large predators such as crocodilians are one of the great public attractions sought after for tourist interactions. Interactions with wild animals and humans can hyperstimulate the hypothalamic‐pituitary‐adrenal axis in the short term, in the case of crocodilians showing an increased corticosterone level, which is indicative of physiological stress. Between September and December 2019, we simulated interactions between tourists and Amazonian crocodilians at Anavilhanas National Park in Central Amazonia, Brazil to evaluate the effects of handling and use of photographic flashes on black caiman (Melanosuchus niger) and spectacled caiman (Caiman crocodilus) on circulating corticosterone and lactate. Corticosterone levels increased 1.7‐fold during handling and 2.7‐fold when exposed to photographic flashes in black caiman but not in spectacled caiman. Increased corticosterone concentrations in black caiman were characterized by an increase caused by handling and were more intense after flashes than in controls, but the combination of handling and flash had no effect. During handling in simulated tourist interactions, anaerobic respiration increased lactate in black caiman but not in spectacled caiman. The effect of simulated tourist interactions with Amazonian crocodilians was dependent on the handling and especially on flash use in black caiman. The results can assist management, conservation programs, and public policies, especially in programs based on tourism interaction with Amazonian crocodilians.

Carbonate compensation depth drives abyssal biogeography in the northeast Pacific.

Abyssal seafloor communities cover more than 60% of Earth's surface. Despite their great size, abyssal plains extend across modest environmental gradients compared to other marine ecosystems. However, little is known about the patterns and processes regulating biodiversity or potentially delimiting biogeographical boundaries at regional scales in the abyss. Improved macroecological understanding of remote abyssal environments is urgent as threats of widespread anthropogenic disturbance grow in the deep ocean. Here, we use a new, basin-scale dataset to show the existence of clear regional zonation in abyssal communities across the 5,000 km span of the Clarion-Clipperton Zone (northeast Pacific), an area targeted for deep-sea mining. We found two pronounced biogeographic provinces, deep and shallow-abyssal, separated by a transition zone between 4,300 and 4,800 m depth. Surprisingly, species richness was maintained across this boundary by phylum-level taxonomic replacements. These regional transitions are probably related to calcium carbonate saturation boundaries as taxa dependent on calcium carbonate structures, such as shelled molluscs, appear restricted to the shallower province. Our results suggest geochemical and climatic forcing on distributions of abyssal populations over large spatial scales and provide a potential paradigm for deep-sea macroecology, opening a new basis for regional-scale biodiversity research and conservation strategies in Earth's largest biome.

Grazing alters the relationship between alpine meadow biodiversity and ecosystem multifunctionality

The relationship between biodiversity and ecosystem multifunctionality (EMF) depends on changes in environmental disturbance. Plant and soil biological diversity can mediate EMF, but how these change in response to grazing disturbance remains unknown. Here we present an 8-year experiment on sheep grazing control in alpine grasslands in Gannan Tibetan Autonomous Prefecture, Gansu Province, China. Plant species richness, FRic (functional richness), PD (Faith's phylogenetic diversity), soil biological diversity (bacterial, fungal, and ciliate diversity), and multiple ecosystem functions were measured and calculated. The results showed that increasing grazing intensity caused a decrease in biodiversity and EMF and that biodiversity and ecosystem function differed significantly (P < 0.05) between grazing intensities. EMF was positively correlated with species richness, functional diversity, and soil bacterial diversity (P < 0.05), with 23.6 %, 10.8 %, and 12.1 % of EMF explained by changes in grazing intensity, respectively. The interaction terms of grazing intensity, plant species richness, and soil biological diversity were negatively correlated with EMF (P < 0.05). This shift in the relationship between plant or soil biological diversity and EMF occurs at a grazing intensity index of around 0.7, i.e., the impact of plant species richness on EMF is more significant when the grazing intensity index is below 0.67. The effect of soil biological diversity on EMF is more substantial when the grazing intensity index is above 0.86. Conclusion: High grazing intensity directly affects soil bulk density and pH and indirectly affects EMF by regulating plant species richness and soil biological diversity changes. Loss of plant and soil biological diversity can have extreme consequences under low and high grazing intensity disturbance conditions. Therefore, we must develop biodiversity conservation strategies for external disturbances to mitigate the effects of land use practices such as grazing disturbances.

Examining Participation in and Supply of Private Land for Voluntary Conservation in Australia’s Tropical Savannas: A Discrete-Continuous Choice Experiment

Australia’s tropical savannas are a vast landscape of grasslands with high biodiversity value. Effective biodiversity conservation in this landscape requires private contributions to complement the under-sized formal conservation estate. The landscape is dominated by rangelands, in particular extensive cattle grazing on pastoral stations which typically measure hundreds or thousands of square kilometers. The paper reports the results of a discrete–continuous (or “two-stage”) choice experiment conducted with savanna pastoralists. A discrete choice experiment explored the stated willingness to participate in two long-term conservation strategies: (i) total exclusion of cattle from designated parcels of land with management of that land for biodiversity, and (ii) the implementation of rotational grazing systems governed by the requirements of biodiversity, among other contractual attributes. An extension question asked about the area that respondents were willing to supply and a contract they were willing to accept. Double-hurdle (type II tobit) modelling was used for combined data analysis. The results show that potential participation in voluntary conservation contracts by pastoralists is primarily influenced by contract attributes, namely, the conservation action required, the stewardship payment received, contract length and whether the contract contains flexibility provisions. Land productivity is also significant. The level of stewardship payment required to incentivize participation in the conservation of grasslands is in line with opportunity costs, in particular option value. The amount of land that pastoralists are willing to supply is determined by the conservation payment as well as farm size and intrinsic motivation. This research illustrates strategies for integrating biodiversity conservation into cattle grazing operations in Australia’s tropical savannas, which are applicable to grasslands globally. It provides data of an economic nature to inform the development of multi-tenure biodiversity conservation strategies.

Promotion of Biodiversity Conservation and Local Livelihoods in Buxa Tiger Reserve: Challenges and Opportunities

The present paper attempts to outline the emerging twin challenges of biodiversity conservation and the promotion of local livelihood opportunities for local people residing in and around the Buxa Tiger Reserve (BTR) in the Indian State of West Bengal. The study is based on a comprehensive review of the existing literature, secondary data collected from various government reports, and interaction with local forest dwellers in and around the nature park. The study finds that although the Buxa Tiger Reserve houses some of the critically threatened species, both flora and fauna, it is under severe pressure from both natural and anthropogenic factors. The natural factors that are threatening the nature park include climate change-induced water scarcity, frequent droughts and erratic rainfall. This has also brought about livelihood insecurity among local inhabitants, which has resulted in human-wildlife conflicts, illegal and rampant wildlife poaching, fragmented landscapes due to encroachment, deforestation, forest fire, the conflict between the forest department and local people, and others. Hence, sustainable use and management of park resources require both effective conservation measures and local livelihood strategies. Efforts should be made for adopting participatory biodiversity conservation strategies in which both park authority and local people work collectively towards achieving desired conservation and livelihood outcomes.

Mangrove Biodiversity Assessment Using UAV Lidar and Hyperspectral Data in China’s Pinglu Canal Estuary

Mangrove forests are a valuable resource for biological and species diversity, and play a critical role in maintaining biodiversity. However, traditional plant biodiversity survey methods, which rely on labor-intensive field surveys, are not suitable for large-scale continuous spatial observations. To overcome this challenge, we propose an innovative framework for mangrove biodiversity assessment and zoning management based on drone low-altitude remote sensing, integrating data such as vertical structure features and spectral diversity features extracted from on-site measurements, airborne LiDAR, and hyperspectral data. This study focuses on the Maowei Sea mangrove community, located in the estuary of China’s first Pinglu Canal since the founding of the People’s Republic of China. Using the proposed framework, we construct an evaluation index for mangrove biodiversity at the levels of species diversity, ecosystem diversity, and landscape diversity, achieving a quantitative calculation of mangrove biodiversity and an evaluation of spatial distribution patterns. The results show that the biodiversity index of mangroves ranges from 0 to 0.63, with an average value of 0.29, and high-biodiversity areas are primarily concentrated in the southwest of the study area, while low-value areas are mainly located in the north. We also select the elevation and offshore distance of mangrove growth for the spatial zoning of biodiversity. The core area of biodiversity occupies the smallest area, at 2.32%, and is mainly distributed in areas with an elevation of 1.43–1.59 m and an offshore distance of 150.08–204.28 m. Buffer zones and experimental zones account for a significant proportion, with values of 35.99% and 61.69%, respectively. Compared to traditional methods for monitoring mangrove biodiversity, such as community field-sample surveys, the proposed method using unmanned-aerial-vehicle LiDAR and hyperspectral coupling technology to assess mangrove biodiversity and establish a zoning management framework is more conducive to formulating mangrove biodiversity conservation strategies. The study provides a feasible solution for the large-scale biodiversity mapping of mangroves in the Maowei Sea at the estuary of the Pinglu Canal.

Assessing the aesthetic attractivity of European butterflies: A web-based survey protocol.

Aesthetic attractivity stands as an underestimated yet fundamental feature of species in conservation biology, significantly driving disproportionate protection efforts towards charismatic species. Despite the evidence, few attempts sought to precisely quantify the impact of aesthetic attractivity in defining priority of species for conservation actions (e.g. inclusion in International Union for Conservation of Nature red lists and protection lists). This study protocol describes the setting of an online test (available from April 2022 to April 2023 at www.unveiling.eu) designed to i) quantify the aesthetic attractivity to humans of the 496 European butterfly species and ii) identify which features (both in the perceived animal and in the perceiver) influence the aesthetic attractivity of a given butterfly species. The test is divided in 5 sections (personal data, ranking, single morphological features, emotional engagement, dispositional variables) aimed at profiling the relation each participant has with the species examined. In the long-term, evaluating butterflies' aesthetic attractivity could facilitate the critical assessment of current conservation strategies, such as the process of selection of flag and umbrella species by research institutions, environmental associations and Non Governative Organizations. This is expected to provide the much-needed evidence to set up unbiased biodiversity conservation strategies and counteract the selective anthropogenic pressure which favours the extinction of unattractive species, being no or less protected compared to charismatic species.

Stand Structure Beats Age for Ground Cover Vegetation in Ageing Hemiboreal Scots Pine and Norway Spruce Stands

Intensifying forest management and a reduction in the rotation period necessitates the development of intensive biodiversity conservation strategies, such as the triad concept, which aims at ensuring habitat connectivity. Such an approach depends on the relationships between biodiversity components and manageable stand characteristics. Mostly, the biological value of stands has been associated with age, although stand structures, which are often intercorrelated with age, might be of primary importance. The relationships between ground cover vegetation, which is a principal component and indicator of the biological value of temperate conifer forests, and stand characteristics were assessed in pre-harvesting/harvesting age and old-growth coniferous stands in the eastern Baltic region (Latvia). The old-growth stands were nearly two times older than the pre-harvesting/harvesting age stands. Both stand groups showed generally similar ground cover flora, though ground cover vegetation showed higher variability in the old-growth stands. The principal gradients of ground cover vegetation were related to light, site fertility, and structural diversity, as well as the degree of deciduous (particularly Betula spp.) admixture in a tree stand. Considering the explicit contrasts, stand age did not affect ground cover vegetation, implying the principal effects of stand structure, which are manageable characteristics. This implies the potential for specific management to aid the ecological connectivity of stands in commercial forest landscapes.

Revisiting environmental management zones toward conserving globally important species in western Philippines

The establishment of environmental management zones is an important strategy for biodiversity conservation. However, identifying and assigning appropriate zones is a challenging task that is critical to the management’s success. The Environmentally Critical Areas Network (ECAN) of the Palawan province is among the management strategies being implemented in the western Philippines. Under this strategy, natural resources needing the highest degree of protection are designated as core zones (CZ). Our study revisited this strategy to assess the current placement of the core zones with respect to species distributions and vegetation types. We conducted a series of field surveys in four municipalities of Palawan to assess the status of biodiversity. Gathered data was used to identify potential critical habitats by generating species distribution models and performing vegetation analysis using land satellite images. The placement of the CZ was evaluated using the identified critical habitats. Our assessments show that many Palawan endemic species persist despite increasing pressures from anthropogenic activities. We also found that a considerable extent of natural forest remains, generally confined in high elevations and steep terrains. The assessment of critical habitats and CZ revealed vital gaps in protection, suggesting that a revision is necessary to accommodate important habitats of threatened and endemic species. Overall, our study highlights the significance of integrating biodiversity data in improving conservation and management strategies, which has been overlooked in the current ECAN zones.

Potential biodiversity map of bird species (Passeriformes): Analyses of ecological niche, environmental characterization and identification of priority conservation areas in southern Patagonia

Different methodologies try to identify priority conservation areas (PCA) to improve habitat conservation and decrease human pressures over bird species at coarse-scale. Map of potential biodiversity (PB) can identify PCA (high PB values) at different scale levels by considering ecological requirements and distributions through potential habitat suitability (PHS) models. The aim was to elaborate a map of PB of bird species based on PHS models to spatially identify PCA in Santa Cruz, Argentina. Moreover, we want to analysis species’ ecology requirements, and evaluate PB values and spatially identify PCA through two scale levels. We computed 47 models using Environmental Niche Factor Analysis (ENFA) on Biomapper software. Each model was visualized and combined to get a unique map of PB. We analyzed ecological requirements by specialization and marginality and PHS maps. Moreover, considering natural environments (regional level) and forest types’ cover (forest landscape level), we evaluated PB values using ANOVAs and identified PCA under different human pressures, using human footprint (HPF) map. Bird species related to Nothofagus forests were most specialist and exhibited a narrower potential distribution than grassland species. At regional level, Magellanic grass steppes displayed the highest PB values, where most of the PCA had high HPF values. At forest landscape level, ecotone N. antarctica forests had the highest PB values, where PCA with low HFP values were outside current protected networking. We conclude that combining PHS models and the map of PB allowed us to improve bird distribution studies and to assist biodiversity conservation strategies under human pressures.

Geographical and climate‐dependent patterns in spatial distributions of snail (Mollusca: Gastropoda) assemblages in freshwater wetlands across Northeast China

Abstract A central goal of community ecology and biogeography involves understanding the spatial patterns of organisms and their underlying mechanisms. Understanding how the structure of wetland biomes vary throughout geographical or climatic gradients has critical implications for the ecological restoration and management of wetlands. However, the geographical patterns of snails in freshwater wetlands and the relative contributions of climatic and local environment variables remain poorly elucidated. We investigated 126 freshwater wetlands across four ecoregions (Da Xing'an Mountains, Songnen Plain, Sanjiang Plain and Changbai Mountains) in Northeast China, and collected 105578 individual snails (Mollusca: Gastropoda) belonging to 17 families, 34 genera and 64 species. Overall, snail richness and functional alpha diversity was higher in the wetlands of the Sanjiang Plain than the other three regions. Multivariate analyses results revealed that the taxonomic, functional and phylogenetic structures of snail assemblages differed significantly across the four regions. Higher taxonomic dissimilarities, as well as functional and phylogenetic dissimilarities existed between the wetlands of the Songnen Plain and the other three regions. The variations in taxonomic, functional and phylogenetic structures of snail assemblages were predominantly explained by climatic variables rather than by local environmental variables. For taxonomic structure, salinity explained the greatest variation among all variables, whereas precipitation seasonality explained the greatest variation for functional and phylogenetic structure. Considering extant patterns in assemblage structure and its predictors, aggravated salinization and seasonality of precipitation are expected to act as powerful factors shaping future assemblages. Also, climate‐related factors cause changes and spatial distribution of invertebrate assemblages of freshwater wetlands should be considered to formulate differentiated strategy for biodiversity conservation.

Potential aboveground biomass increase in Brazilian Atlantic Forest fragments with climate change.

Fragmented tropical forest landscapes preserve much of the remaining biodiversity and carbon stocks. Climate change is expected to intensify droughts and increase fire hazard and fire intensities, thereby causing habitat deterioration, and losses of biodiversity and carbon stock losses. Understanding the trajectories that these landscapes may follow under increased climate pressure is imperative for establishing strategies for conservation of biodiversity and ecosystem services. Here, we used a quantitative predictive modelling approach to project the spatial distribution of the aboveground biomass density (AGB) by the end of the 21st century across the Brazilian Atlantic Forest (AF) domain. To develop the models, we used the maximum entropy method with projected climate data to 2100, based on the Intergovernmental Panel on Climate Change Representative Concentration Pathway (RCP) 4.5 from the fifth Assessment Report. Our AGB models had a satisfactory performance (area under the curve > 0.75 and p value < .05). The models projected a significant increase of 8.5% in the total carbon stock. Overall, the projections indicated that 76.9% of the AF domain would have suitable climatic conditions for increasing biomass by 2100 considering the RCP 4.5 scenario, in the absence of deforestation. Of the existing forest fragments, 34.7% are projected to increase their AGB, while 2.6% are projected to have their AGB reduced by 2100. The regions likely to lose most AGB-up to 40% compared to the baseline-are found between latitudes 13° and 20° south. Overall, although climate change effects on AGB vary latitudinally for the 2071-2100 period under the RCP 4.5 scenario, our model indicates that AGB stocks can potentially increase across a large fraction of the AF. The patterns found here are recommended to be taken into consideration during the planning of restoration efforts, as part of climate change mitigation strategies in the AF and elsewhere in Brazil.

Estimating resistance surfaces using gradient forest and allelic frequencies.

Understanding landscape connectivity has become a global priority for mitigating the impact of landscape fragmentation on biodiversity. Connectivity methods that use link-based methods traditionally rely on relating pairwise genetic distance between individuals or demes to their landscape distance (e.g., geographic distance, cost distance). In this study, we present an alternative to conventional statistical approaches to refine cost surfaces by adapting the gradient forest approach to produce a resistance surface. Used in community ecology, gradient forest is an extension of random forest, and has been implemented in genomic studies to model species genetic offset under future climatic scenarios. By design, this adapted method, resGF, has the ability to handle multiple environmental predicators and is not subjected to traditional assumptions of linear models such as independence, normality and linearity. Using genetic simulations, resistance Gradient Forest (resGF) performance was compared to other published methods (maximum likelihood population effects model, random forest-based least-cost transect analysis and species distribution model). In univariate scenarios, resGF was able to distinguish the true surface contributing to genetic diversity among competing surfaces better than the compared methods. In multivariate scenarios, the gradient forest approach performed similarly to the other random forest-based approach using least-cost transect analysis but outperformed MLPE-based methods. Additionally, two worked examples are provided using two previously published data sets. This machine learning algorithm has the potential to improve our understanding of landscape connectivity and inform long-term biodiversity conservation strategies.

Effects of Environmental Factors on Bird Communities in Different Urbanization Grades: An Empirical Study in Lishui, a Mountainous Area of Eastern China.

The rapid development of urbanization has changed landscape patterns and biological habitats severely and, therefore, affected biodiversity. In this study, we selected 75 townships in Lishui, a mountainous area in eastern China, to conduct bird surveys for two years. We analyzed the birds' composition characters in townships with different levels of development in order to identify the effects on bird diversity of the urban development level, land cover pattern, landscape pattern, and other factors. In total, 296 bird species from 18 orders and 67 families were recorded between December 2019 and January 2021. A total of 166 species of birds belonged to Passeriformes (56.08%). The seventy-five townships were divided into three grades by K-means cluster analysis. The average number of bird species, richness index, and diversity index were higher in G-H (highest urban development level) compared with the other grades. At the township level, landscape diversity and landscape fragmentation were the key factors that positively affected the bird species number, diversity index, and richness index. Landscape diversity had a greater effect than landscape fragmentation, particularly on the Shannon-Weiner diversity index. The diversity and heterogeneity of urban landscapes could be improved by constructing biological habitats in future urban development planning to maintain and increase biodiversity. The results obtained in this study provide a theoretical basis for urban planning in mountainous areas, and a reference for policymakers to formulate biodiversity conservation strategies, construct reasonable biodiversity patterns, and solve practical biodiversity conservation problems.

Biophysical delineation of grassland ecological systems in theState of Rio Grande do Sul, Southern Brazil

Different types of grasslands cover much of the Earth’s surface. At a closer look, these grasslands present unique and specific floristic and biophysical characteristics. Following an ecosystem approach, we propose a new regionalization of the grassland landscapes that correspond to two thirds of the surface of the state of Rio Grande do Sul. The biophysical factors that control energy and water availability for living organisms are the basis of our analysis. The dominant macroclimate is humid subtropical, but at a meso-scale (1:250,000), additional constraints such as relief and soils modulate this availability. With the support of Geographic Information Systems it was possible to delimit ten grassland ecological systems based on the flora and its relationship to the respective biophysical characteristics as derived from elevation, slope, and soil data. Our analysis adds the currently available floristic data on grasslands to previously established vegetation maps of the same geopolitical territory. Therefore, we extend the hitherto limited understanding of the complexity of the grassland systems. The results add new knowledge to the regionalization of the grassland vegetation of southern Brazil. The proposed delimitation provides a framework for various purposes, such as ecological and biodiversity studies, conservation and mitigation strategies, and sustainable land use.

Spatial distribution and temporal variation of tropical mountaintop vegetation through images obtained by drones

Modern UAS (Unmanned Aerial Vehicles) or just drones have emerged with the primary goal of producing maps and imagery with extremely high spatial resolution. The refined information provides a good opportunity to quantify the distribution of vegetation across heterogeneous landscapes, revealing an important strategy for biodiversity conservation. We investigate whether computer vision and machine learning techniques (Object-Based Image Analysis—OBIA method, associated with Random Forest classifier) are effective to classify heterogeneous vegetation arising from ultrahigh-resolution data generated by UAS images. We focus our fieldwork in a highly diverse, seasonally dry, complex mountaintop vegetation system, the campo rupestre or rupestrian grassland, located at Serra do Cipó, Espinhaço Range, Southeastern Brazil. According to our results, all classifications received general accuracy above 0.95, indicating that the methodological approach enabled the identification of subtle variations in species composition, the capture of detailed vegetation and landscape features, and the recognition of vegetation types’ phenophases. Therefore, our study demonstrated that the machine learning approach and combination between OBIA method and Random Forest classifier, generated extremely high accuracy classification, reducing the misclassified pixels, and providing valuable data for the classification of complex vegetation systems such as the campo rupestre mountaintop grassland.

THE COMPLEMENTARY USE OF CHARCOAL NUMBER AND MORPHOLOGY TO RECONSTRUCT FIRE HISTORY IN A LATE HOLOCENE PEAT SEQUENCE FROM NW ROMANIA

Fires influence basic ecosystem processes, including the distribution, the structure and the composition of vegetation, as well as the carbon cycle and climate at the global scale. Long-term knowledge (i.e., centuries or millennia) of fire regime history and forest fire ecology and dynamic in local environments is necessary for sustainable ecosystem management and biodiversity conservation strategies. Charcoal is a widely used proxy for reconstructing fire regime history and vegetation burning. Charcoal analysis is based on the accumulation of charred particles in depositional environments such as lakes and bogs, during and shortly after the occurrence of fire events. Ombrotrophic peat bogs are sensitive to local environmental changes and, given that the deposition of allochthonous material is exclusively atmospheric, they are ideal archives for reconstructing charcoal fluxes resulting from biomass burning. This study quantifies charcoal abundance (number) in a peat sequence extracted from Tăul Mare ombrotrophic peat bog (Văratec Massif, Lăpuş Mts, north-western Romania) aiming to reconstruct local fire history over the last 3000 years and to explore potential drivers. As a novelty, observations concerning the morphology of charred fragments are added to provide additional information on the type of material burnt (woody vegetation or herbs), fire severity and charcoal source area, thus strengthening the interpretation of the charcoal record. Results showed moderate fire activity between 3000 and 2300 cal yr BP, which slightly decreased between 2300 and 700 cal yr BP and varied considerably throughout the last 700 years. Several major fire episodes were further identified around 2500, 1700, 1300, 900 and 500 cal yr BP. Of these, the first four overlapped two phases of progressive landscape opening and extension of pastoral activities, while the latter was unprecedented in the entire history of the bog and was likely associated with the development of mining activities in the area. This study provides the first complementary use of charcoal morphologies in fire history reconstruction in Romania and adds a valuable perspective on the extent of past human impact on the mid-elevation mountain landscape.