Vegetation Physiognomy Research Articles

Biogeographical Origins of Caatinga Squamata Fauna

ABSTRACTAimSeveral lines of evidence have noted that open vegetation biomes in the Neotropics are younger than moist forests, leading us to question which historical processes shaped the current species distribution patterns in these new biome formations. Here we investigate the temporal patterns of speciation and colonisation from surrounding biomes (Amazonia, Atlantic Forest and Cerrado) in the Caatinga historical assembly of squamate species, to understand the role of geomorphological events and climate change in driving its diversification.LocationNeotropics.TaxonSquamata (snakes, lizards and amphisbaenians).MethodsWe used a phylogenetic tree and occurrence data for 459 squamate species distributed throughout four different biomes (Amazonia, Atlantic Forest, Cerrado and Caatinga) to reconstruct ancestral geographic ranges using the R package BioGeoBEARS. We used BAMM to estimate the rates of species diversification.ResultsOur results indicate that the current diversity patterns of squamates in the Caatinga were a result of pervasive faunal exchanges from adjacent biomes since the Paleogene, with similar numbers of dispersal events in each source area. The Neogene period was determinant in the diversification process, leading to the current assembly patterns of this group in the Caatinga.Main ConclusionsThe landscape transformation and climate change that increased aridity in northeastern Brazil probably shaped the diversification of dry‐adapted squamates in the Caatinga, like tropidurid lizards. However, the Pleistocene climatic fluctuations associated with the highly heterogeneous gradients of topography, geology, soils, climatic conditions, and different vegetation physiognomies could have facilitated faunal exchange with their neighbouring forested biomes, explaining the current presence of some typical forested lineages inside the Caatinga domain and help us to clarify the current distribution patterns of squamates in this region.

Diversity and dominance in bird assemblages across habitats in the Ñeembucú wetlands complex

AbstractUnderstanding how diversity responds to habitat heterogeneity in a landscape is a central issue for implementing effective conservation plans. In this study, we analyzed how the composition and abundance of neotropical bird assemblages vary among habitats in the Ñeembucú Wetlands Complex, the largest wetland system in Paraguay. Bird surveys were conducted during 1 year within dominant habitats in the landscape: riparian forests, natural grasslands, savannas, and anthropized sites. The Ñeembucú Wetlands Complex showed a high bird richness (209 species) that contrasted with a pattern of dominance by a small set of 16 species that comprised half of the abundance. This set of oligarchic species consists of generalist species that exploited a wide variety of habitats and were well adapted to human disturbance, contributing to an important overlap in the composition of assemblages. However, despite this overall similarity, there is still significant differentiation in bird assemblages, especially between habitats with the most contrasting vegetation physiognomy. Riparian forests and savannas showed higher diversity values than the more structurally homogeneous grasslands. Also, all natural habitats showed, in general, higher diversity values than anthropized sites. Oligarchic species had higher importance in anthropized environments, which also had the most uneven distribution of abundance between species, indicating the dominance by a smaller number of species and the loss of ecological diversity as farmland and urban development increase.Abstract in Spanish is available with online material.

How to map biomes: Quantitative comparison and review of biome‐mapping methods

AbstractBiomes are large‐scale ecosystems occupying large spaces. The biome concept should theoretically facilitate scientific synthesis of global‐scale studies of the past, present, and future biosphere. However, there is neither a consensus biome map nor universally accepted definition of terrestrial biomes, making joint interpretation and comparison of biome‐related studies difficult. “Desert,” “rainforest,” “tundra,” “grassland,” or “savanna,” while widely used terms in common language, have multiple definitions and no universally accepted spatial distribution. Fit‐for‐purpose classification schemes are necessary, so multiple biome‐mapping methods should for now co‐exist. In this review, we compare biome‐mapping methods, first conceptually, then quantitatively. To facilitate the description of the diversity of approaches, we group the extant diversity of past, present, and future global‐scale biome‐mapping methods into three main families that differ by the feature captured, the mapping technique, and the nature of observation used: (1) compilation biome maps from expert elicitation, (2) functional biome maps from vegetation physiognomy, and (3) simulated biome maps from vegetation modeling. We design a protocol to measure and quantify spatially the pairwise agreement between biome maps. We then illustrate the use of such a protocol with a real‐world application by investigating the potential ecological drivers of disagreement between four broadly used, modern global biome maps. In this example, we quantify that the strongest disagreement among biome maps generally occurs in landscapes altered by human activities and moderately covered by vegetation. Such disagreements are sources of bias when combining several biome classifications. When aiming to produce realistic biome maps, biases could be minimized by promoting schemes using observations rather than predictions, while simultaneously considering the effect of humans and other ecosystem engineers in the definition. Throughout this review, we provide comparison and decision tools to navigate the diversity of approaches to encourage a more effective use of the biome concept.

Drivers of heterogeneity in tundra vegetation productivity on the Yamal Peninsula, Siberia, Russia

The direction and magnitude of tundra vegetation productivity trends inferred from the normalized difference vegetation index (NDVI) have exhibited spatiotemporal heterogeneity over recent decades. This study examined the spatial and temporal drivers of Moderate Resolution Imaging Spectroradiometer Max NDVI (a proxy for peak growing season aboveground biomass) and time-integrated (TI)-NDVI (a proxy for total growing season productivity) on the Yamal Peninsula, Siberia, Russia between 2001 and 2018. A suite of remotely-sensed environmental drivers and machine learning methods were employed to analyze this region with varying climatological conditions, landscapes, and vegetation communities to provide insight into the heterogeneity observed across the Arctic. Summer warmth index, the timing of snowmelt, and physiognomic vegetation unit best explained the spatial distribution of Max and TI-NDVI on the Yamal Peninsula, with the highest mean Max and TI-NDVI occurring where summer temperatures were higher, snowmelt occurred earlier, and erect shrub and wetland vegetation communities were dominant. Max and TI-NDVI temporal trends were positive across the majority of the Peninsula (57.4% [5.0% significant] and 97.6% [13.9% significant], respectively) between 2001 and 2018. Max and TI-NDVI trends had variable relationships with environmental drivers and were primarily influenced by coastal-inland gradients in summer warmth and soil moisture. Both Max and TI-NDVI were negatively impacted by human modification, highlighting how human disturbances are becoming an increasingly important driver of Arctic vegetation dynamics. These findings provide insight into the potential future of Arctic regions experiencing warming, moisture regime shifts, and human modification, and demonstrate the usefulness of considering multiple NDVI metrics to disentangle the effects of individual drivers across heterogeneous landscapes. Further, the spatial heterogeneity in the direction and magnitude of interannual covariation between Max NDVI, TI-NDVI, and climatic drivers highlights the difficulty in generalizing the effects of individual drivers on Arctic vegetation productivity across large regions.

ECOLOGICAL FUNCTIONALITY OF FOREST AND STREAM CORRIDORS IN AN AREA OF THE PLAINS PIEDMONT IN CASANARE

Between 2010 and 2020 a study was conducted on the functionality of the ecological corridors within the San José de Matadepantano farm, a property of 811 ha located in plains piedmont, which alternates poorly drained savannas, swamps, and forests, with land uses for agriculture, livestock, and the infrastructure of a rural university campus. To evaluate the functionality of the forest corridors, length, amplitude, coverage area, and continuity metrics within the landscape were estimated using multiannual LANDSAT images; additionally, field visits were made to record possible forest gaps that could affect the flow of fauna through the corridors. In order to determine the functionality of the stream corridors, four sampling points were chosen along caños Tiestal and Güio, where physiographic and bathymetric profiles were modeled using the SURFER 15 software, in addition, spatial heterogeneity was calculated using the Shannon-Wiener index, physiognomy and floristic composition of the streamside vegetation was represented in scale graphic profiles, the percent distribution of aquatic habitats was determined and species diversity of fish communities was calculated. Findings obtained during the last decade allow us to conclude that the ecological corridors maintain their functionality with an active biotic flow in both forest and stream corridors. However, critical points were detected where the forests could lose their connectivity, which would affect the sustainability and transit of regional biodiversity.

Influence of environmental conditions and initial sapling size in Nothofagus survival and growth: Implications for restoration of burnt sub‐Antarctic forests

AbstractThe sub‐Antarctic forests in Tierra del Fuego mountains are considered one of the few remaining wilderness areas on the planet; however, human disturbances like wildfires, exotic species, and so forth exacerbate their degradation. In 2012, a human‐caused wildfire started in a remote forest‐mountain area, and 2 years after that, a reforestation project began to restore the natural canopy layer. Saplings of the native Nothofagus trees were obtained through the bare root method from undisturbed areas. In this study, we evaluated the influence of (1) macro‐ (considering natural topography and vegetation physiognomy) and micro‐environments (topography, canopy cover, substrate, and understory cover) affected by fire; and (2) the extraction size of the saplings (initial size), on survival and growth of planted saplings, over 5 years. Total sapling survival was 41.4% with a mean growth rate of 8.46 cm year−1. Survival and growth were influenced by the studied variables. At a macro‐environment level, tree saplings showed higher success in well‐drained zones, meanwhile at the micro‐environment level saplings performed better in those that contribute to retain soil moisture and avoiding evapotranspiration. We conclude that environmental features influence differentially depending on the scale of analysis. To restore burnt temperate forests applying the bare root method, we recommended using Nothofagus saplings <40 cm tall for better results. In this sense, we demonstrated the effectiveness of the method since comparable results were obtained in other restoration experiences. This method can also be applied in areas without nursery material, when the biology of tagged plants was appropriated, for example shallow growth of root systems, formation of natural tree seedling banks. This work represents one of the few medium‐term restoration experiences reported for the southernmost forests of the planet: our findings could be applied in other reforestation experiences, making noticeable improvements in the recovery process.

Ecology and phenology of the Dysderidae (Araneae) in the Djurdjura National Park (Algeria)

AbstractThe ecology and phenology of the Dysderidae (Araneae) were investigated in two different sites (Tala‐Guilef and Tikjda), located at opposite slopes of the Djurdjura National Park in Algeria. The following questions were investigated: Are there any endemic species in the studied area? Do the slopes' orientation influence the abundance, richness and diversity of these spider communities? Are the activity and the vital cycle of the three most abundant species different in the two different plant physiognomies (cedar forests and alpine grasslands)? The Dysderidae were collected monthly for 2 years using pitfall traps. In total, 1532 specimens were collected: 333 males, 389 females and 381 juveniles in Tala‐Guilef and 230 males, 66 females and 133 juveniles in Tikjda. Among the total of 10 species sampled, three species belonging to three genera in Tala‐Guilef, 10 species belonging to four genera in Tikdja and four endemic species was recorded. The slope orientation influence the abundance and the species richness. The activity and the vital cycle of the three most abundant species were not different in the cedar forests and alpine grasslands. For these species, no relationship was found between the activity cycle and the vegetation physiognomy.

Ant Diversity Is Enhanced by Ecological Infrastructures in Agroecosystems: A Case Study in Irrigated Mediterranean Farmland

We aimed at assessing the role of ecological infrastructures (EI) in promoting ant biodiversity in floodplain Mediterranean agricultural crops. We examined and compared ant communities at the interface between EI (remnant vegetation patches) and adjoining agricultural matrix (maize, rice, others) in irrigated farmland. The study was conducted in 2019, in two agricultural landscapes in the valleys of the rivers Tagus and Sorraia, Central Portugal. We used the Akaike information criterion for model selection and to distinguish among a set of possible models describing the relationship between: the ant richness in the agricultural matrix and drivers associated with the surrounding landscape and crop type; the ant richness in EI and the habitat quality of EI patches, the characteristics of the surrounding landscape, and the presence of invasive ant species. We found that: EI patches supported a higher ant diversity and an overall specialized ant community, distinctive from the agricultural matrix; location but not vegetation physiognomy influenced ant diversity; ant richness within the agricultural matrix decreased with the distance to the EI, and that this relationship was influenced by the crop type; and that ant richness in the EI was associated with the absence of the invasive Argentine ant and the area of terrestrial EI in the surrounding landscape.

Biodiversity in Urban Areas: The Extraordinary Case of Appia Antica Regional Park (Rome, Italy).

The first inventory of the flora of Appia Antica Regional Park (Italy), one of the largest protected urban areas in Europe (4580 ha), its biological, ecological and biogeographical composition, and notes of the vegetation physiognomies and landscape are presented; physical characteristics of the territory (geomorphology, lithotypes, and phytoclimate) are also given. The landscape is defined by an agricultural matrix with natural and seminatural areas as patches, and riparian vegetation communities as corridors. The vegetation physiognomies are represented by types linked to the Mediterranean climate (mixed, Mediterranean, and riparian forests; scrubby, rocky, aquatic, and helophytic vegetation; anthropogenic communities). The floristic list includes 714 taxa (104 families and 403 genera). Therophytes prevail over hemicryptophytes; woody flora comprises about 30% of alien species. As regards chorotypes, together with a considerable number of Mediterranean species, there are many exotic species with wide distribution areas testifying to a long-lasting anthropic impact. Floristic novelties (european, national, and regional levels) for 21 taxa are reported. The extraordinary species diversity discovered (43% of flora of Rome and 20% of regional flora) is linked to the landscape heterogeneity, the characteristics of which are: (1) persistence of residual natural patches, (2) occurrence of quite well-preserved aquatic habitats and humid meadows, (3) a rich anthropogenic flora, (4) an interesting flora of archeological sites, (5) occurrence of species not common in Latium, (6) occurrence of populations of aliens in crops (which cause economic impact), (7) presence of aliens on archeological ruins (which cause economic-social impacts). The extensive set of data provided represents a general base framework for guiding future research efforts and landscape action plans consistent with environmental sustainability.

Monitoring and Management of Asan Reservoir Wetland and Environs using High Resolution Satellite data

Asan Conservation Reserve (ACR) is one of 42 wetlands of International Importance under Ramsar convention and lies in the Central Asian-Indian Flyway and East Asian-Australian Flyway of migratory birds in Doon Valley in Western Himalaya. The valley-landscape is unique and complex with a mix of land use/land cover such as forests, rivers, urban as well agricultural landscape in the Himalayan Biodiversity Hotspot region with high seasonality, water flow and area fluctuations, vegetation physiognomy and phenology, tourism, etc. Even though the migratory and resident birds occupy wetland for most of their stay time, however, the role of the adjacent land use practices play a very important role in food supply chain. We used six-time high resolution time-series temporal (summer and winter) satellite images of LISS IV sensor for the years 2004, 2013 and 2016 to understand the wetland dynamics and its unique ecological significance in terms of conservation and management of ACR for avifauna, specially migratory birds and aquatic vegetation. The area analysis of wetland and its environs between 2004 to 2016 indicates decreasing trend of about 3% (0.14 km 2 ), 4% (0.65 km 2 ), 1% (0.18 km 2 ) and 15% (2.02 km 2 ) in wetland area, riverine scrub, mango orchards and agriculture land, respectively. An increasing trend has been observed by 4% (0.348 km 2 ), 1% (0.067 km 2 ), 3% (0.18 km 2 ), 4% (0.2 km 2 ) and 5% (0.35 km 2 ) in settlement area, siltation, total forest cover, water body and wet riverbed, respectively. However, dry riverbed has remained almost unchanged occupying about 17%. The water and vegetation ratio is nearly ideal in the ratio of 60:40, and if needed, desiltation may be carried after mid-March.

Palynological and microfossil-based environmental reconstruction at 7,147–6,435 cal yr BP of the Lagoa Comprida coastal lagoon in the restinga de Jurubatiba National Park, Rio de Janeiro, Brazil

The restinga vegetation and environment dynamics during the Mid-Holocene have been reconstructed through microfossil analysis of a 153 cm-long core from the Lagoa Comprida coastal lagoon of the Parque Nacional Restinga de Jurubatiba (Restinga de Jurubatiba National Park), in the State of Rio de Janeiro, Brazil. The analysis was supported by core stratigraphy, 14C dating, and evaluation of microfossil frequency and concentration. Core sediments were dated from ∼7,147 to 6,435 cal yr BP. Four zones of environmental changes were characterized. A high concentration of marine diatoms was recorded in the basal portion of the core, suggesting possible sea-water influence, corroborating a Holocene Marine Transgression event. The marine diatoms disappeared from the record before ∼7,005 cal yr BP when a major inflow of freshwater began. Palynoforaminifers remained until ca. 6,470 cal yr BP, revealing a mixohaline environment. The restinga vegetation was present in the surroundings from the beginning of the record. The open-scrub plant community was predominant, mainly characterized by Solanum, Borreria, Euphorbia, Pteridium, Garcinia, Guapira and Protium. This plant formation is the most representative vegetation physiognomy in the area nowadays. Clusia lanceolata was well established during the period studied but has since changed its distribution limit to being dominant further south, in the municipality of Maricá.

Temperature or competition: Which has more influence on Mediterranean ant communities?

Temperature and competition are two of the main factors determining ant community assemblages. Temperature may allow species to forage more or less efficiently throughout the day (in accordance with the maximum activity temperature of each species). Competition can be observed and quantified from species replacements occurring during resource exploitation. We studied the interspecific competitive interactions of ant communities from the Doñana Biological Reserve (southern Spain). Ants were sampled from pitfall traps and baits in three habitats with contrasted vegetation physiognomy (savin forest, pine forest, and dry scrubland). We measured the temperature during the competitive interactions between species and created a thermal competition index (TCI) to assess the relative contribution of temperature and numerical dominance to the competitive outcomes. Temperature had unequal effects on ant activity in each type of habitat, and modulated competitive interactions. The TCI showed that a species’ success during pair interactions (replacements at baits) was driven by the proportion of workers between the two competing species and by the species-specific effect of temperature (how advantageous the temperature change is for each species during bait replacement). During competitive interactions, the effect of temperature (higher values of TCI) and numeric supremacy (higher worker proportion) gave higher success probabilities. Interspecific competitive relationships in these Mediterranean ant communities are habitat dependent and greatly influenced by temperature.

Remote sensing-based assessment of land degradation and drought impacts over terrestrial ecosystems in Northeastern Brazil

The spatio-temporal assessment of water and carbon fluxes in Brazil's Northeast region (NEB) allows for a better understanding of these surface flux patterns in areas with different vegetation physiognomies. The NEB is divided into four biomes: Amazon, Cerrado, Caatinga, and Atlantic Forest. Land degradation is a growing problem, particularly in susceptible areas of the Caatinga biome, such as the seasonally dry tropical forest. Furthermore, this region has experienced climatic impacts, such as severe droughts. Due to increasing human pressure, the Caatinga's natural land cover undergoes drastic changes, making it a region particularly vulnerable to desertification. In this study, the Moderate Resolution Imaging Spectroradiometer (MODIS) estimates of evapotranspiration (ET) and gross primary production (GPP) were validated in two contrasting areas, dense Caatinga and sparse Caatinga, using eddy covariance (EC) data and then investigated their behavior over 21 years (2000–2021) for the NEB. MODIS products explained around 60% of the variations in ET and GPP, showing higher accuracy in dense Caatinga, while areas of sparse Caatinga presented the lowest GPP, indicating that land degradation has reduced the photosynthetic activity of the vegetation in this area. Based on the analysis of ET and GPP over 21 years, we observed a greater dependence of the sparse Caatinga on climate variability, demonstrating a stronger resilience of dense Caatinga to climate effects. In comparison with the other biomes of the NEB region, we found lower rates of ET and GPP in the Caatinga biome, with averages similar to the Sparse Caatinga. In comparison with the other biomes in the NEB region, we found the lowest averages of ET and GPP in the Caatinga biome, similar to values found in the sparse Caatinga. In forest areas, similar to the monitored DC, they allowed the Caatinga to behave closer to the other biomes present in the region.

Field experiments on mechanisms influencing species boundary movement under climate change

ScopeCurrently knowledge is weak about which plant species boundaries are determined directly by climate and soil factors, versus which are mediated by biotic interactions, such as exclusion by superior competitors or by pathogens. Under moving climate zones the difference is important. For example, will warm boundaries shrink poleward of their own accord, or only following invasion by other species? What research will most effectively strengthen our understanding of this fundamental issue in ecology?ConclusionsTraditionally the required experiment has been transplant beyond the species boundary, together with density manipulation of putative competitors, herbivores, pathogens or facilitators. But now climate zones are being moved across species distributions, creating a different sort of experiment. In order to learn efficiently from this massive inadvertent experiment, exposure to new climate needs to be combined with experimental manipulation of other factors. Because range extensions are likely to be spatially patchy, these experiments need to be geographically extensive, to be sustained over 2–4 decades, and to be twinned with wide-area population monitoring via drones and other remote sensing. Highest priorities for experimental manipulation would be removal of competition, and provision of seedlings. Highest priorities for locations would be zones where vegetation physiognomy changes, such as woodlands into grasslands, or rainforest into fire-prone forest.

The location and vegetation physiognomy of ecological infrastructures determine bat activity in Mediterranean floodplain landscapes

Ecological infrastructures (EI), defined as natural or semi-natural structural elements, are important to support biodiversity and could play a crucial role in counteracting the well-known impacts of intensive agriculture. Yet, the importance of EI remains largely unexplored in Mediterranean agricultural landscapes and for species providing essential ecosystem services such as bats. Here, we evaluated the role of different EI types – in terms of location (riparian vs terrestrial) and vegetation physiognomy (woody vs non-woody) – in shaping bat guild activity in crop fields located in the floodplains of the Iberian Peninsula. We recorded 60,732 bat sequences in 96 crop fields and characterised 106 EI patches via an adaptation of the Biodiversity Potential Index (BPI). We found that the activity of mid-range echolocators (MRE) and long-range echolocators (LRE) was twofold higher when the nearest EI patch was riparian (i.e., contiguous to a watercourse) than when it was terrestrial. When assessing changes in bat activity in crop fields in relation to a gradient distance from EI types, our results revealed both distinct and similar effects of the location and vegetation physiognomy of the EI on bat guilds. For instance, while only the LRE guild positively responded to the proximity of woody EI, both MRE and LRE showed a marked increase of activity when increasing distances to non-woody EI, thus suggesting low bat activity levels near these features. Our habitat quality assessment also revealed that woody EI and riparian EI had higher biodiversity potential and related habitat quality, thus contributing to our understanding of bat responses to EI type in crop fields. As riparian areas are rarely targeted in biodiversity-friendly measures in farmland, we strongly recommend including riparian EI (especially the woody type) in conservation planning as they are crucial for both biodiversity conservation and ecosystem functioning.

Diversity and regeneration strategies in woody plant communities of the Mediterranean Basin: Vegetation type matters

The Mediterranean Basin has distinct vegetation types shaped by fire, herbivory, and various human activities. Based on data from 83 belt transects of 10 × 40 m in 28 study sites for five physiognomic vegetation types (semi-closed forest, open forest, closed shrubland, open shrubland, and scrubland) in southwestern Anatolia (Turkey), we analyzed woody species diversity, woody community composition, and vegetation structure of study sites. We used the growth form and regeneration strategy for functional comparisons of physiognomic vegetation types. We found clear distinctions in diversity, species composition, and functional structure of woody plant community across five physiognomic vegetation types. The forest-shrubland-scrubland distinction was the most apparent one. Despite similarities in the woody species richness and Shannon diversity, open and closed vegetation states of forests and shrublands also differed regarding the density and cover of mature individuals and the density of saplings in different functional groups. Non-metric multidimensional scaling analyses and indicator species analyses also indicated clear distinctions among physiognomic vegetation types and openness states. Our findings indicate the necessity of a more complex description of vegetation types in the Mediterranean Basin. The results suggest that open and closed vegetation states of forests and shrublands are functionally distinct vegetation types.

Vegetation–environment relationship and floristic diversity of Wadi Al-Sharaea, Makkah Province, Saudi Arabia

Due to their biological significance, physiographic variation, and environmental gradients, desert wadis are essential habitats for socioeconomic development. The current study aims to enrich the knowledge about the importance of Wadi Al-Sharaea, Makkah as a biodiversity hotspot for desert ecosystems in terms of floristic composition, community structure, potential economic uses of identified plants, and behaviour of the common species along soil physicochemical gradients. To collect the data, 95 stands distributed in 17 sampling sites were selected to represent the vegetation physiognomy along the wadi. During the field survey, 110 species belonging to 77 genera and 33 families were discovered with Poaceae family dominating. Therophytes were the dominant life form, and bioregional elements were the dominant chorotype. The TWINSPAN analysis resulted in nine vegetation groups (VGs), which were distinctly segregated on the two axes of DECORANA. Rhiza stricta dominated three VGs (G, H, and I) with Citrullus colocynthis, Polycarpaea repens, and Aristida funiculata, respectively, were codominant species. The Principal Component Analysis (PCA) ordination clarified that the pH, EC, TDS, Mg, and gravels had the most significant effect on the plant communities. Regarding the Pearson correlations, some plant communities were positively affected by some soil variables (e.g., pH, HCO3, K, and Cl), while others were negatively affected by other variables (e.g., EC, TDS, Ca, SO4, and Cl). The species richness varied from 1.5 species stand−1 in Maerua crassifolia-Cynanchum radians community (VG: A) to 21.0 species stand−1 in Citrullus colocynthis-Hypertelis cerviana (VG: B). The low species diversity in some plant communities indicated that the original vegetation was subjected to destruction, and consequently, habitat rehabilitation is urgently required.

Microbial Communities Along 2,3,7,8-tetrachlorodibenzodioxin Concentration Gradient in Soils Polluted with Agent Orange Based on Metagenomic Analyses.

The 2,3,7,8-tetrachlorodibenzodioxin (TCDD), a contaminant in Agent Orange released during the US-Vietnam War, led to a severe environmental crisis. Approximately, 50years have passed since the end of this war, and vegetation has gradually recovered from the pollution. Soil bacterial communities were investigated by 16S metagenomics in habitats with different vegetation physiognomies in Central Vietnam, namely, forests (S0), barren land (S1), grassland (S2), and developing woods (S3). Vegetation complexity was negatively associated with TCDD concentrations, revealing the reasoning behind the utilization of vegetation physiognomy as an indicator for ecological succession along the gradient of pollutants. Stark changes in bacterial composition were detected between S0 and S1, with an increase in Firmicutes and a decrease in Acidobacteria and Bacteroidetes. Notably, dioxin digesters Arthrobacter, Rhodococcus, Comamonadaceae, and Bacialles were detected in highly contaminated soil (S1). Along the TCDD gradients, following the dioxin decay from S1 to S2, the abundance of Firmicutes and Actinobacteria decreased, while that of Acidobacteria increased; slight changes occurred at the phylum level from S2 to S3. Although metagenomics analyses disclosed a trend toward bacterial communities before contamination with vegetation recovery, non-metric multidimensional scaling analysis unveiled a new trajectory deviating from the native state. Recovery of the bacterial community may have been hindered, as indicated by lower bacterial diversity in S3 compared to S0 due to a significant loss of bacterial taxa and recruitment of fewer colonizers. The results indicate that dioxins significantly altered the soil microbiomes into a state of disorder with a deviating trajectory in restoration.

Flora and physiognomy of Caatinga vegetation over crystalline bedrock in the northern Caatinga domain, Brazil

Abstract The Seasonally Dry Tropical Forests and Woodlands biome (SDTFW) has its largest nucleus in the Caatinga domain. We characterized the flora and physiognomy of the vegetation in the Pedra da Andorinha Wildlife Refuge (RPA), in Ceará, Brazil. Plant collections were made between March/2015 and May/2021, applying usual botanical methods. All material was deposited in HUVA herbarium. The phytosociological studies covered five 50 m x 50 m plots established (1.25 ha) in which all individuals with diameters at soil level ³ 3 cm were inventoried. We identified 266 vascular plants species distributed among 185 genera and 67 families, including one fern (Marsilea deflexa - Marsileaceae). Fabaceae had the greatest species richness (38 spp.), while Ipomoea was the richest genus (9 spp.). 43.6% of all plant species were herbaceous, with a predominance of therophytes (57.5% of all herbaceous plants). The phytosociological study sampled 1,988 individuals distributed among 24 species of 13 families. The species with the greatest important value were Cordia oncocalyx (Boraginaceae) and Croton blanchetianus (Euphorbiaceae). We classify the local physiognomy as typical caatinga sensu stricto vegetation and rocky vegetation on inselbergs and outcrops. We highlight the richness of herbaceous plants in the local community, which surpass the richness of the woody component.

SYSTEMATIC REVIEW: THE MAIN METHODS OF RESTITUTION OF DEGRADED AREAS IN THE CERRADO

The Cerrado occupies 24% of the Brazilian territory, half Amazon extension, and despite having the richest flora among the world’s savannas, it has been suffering deforestation rates as same as Amazon. Consequently, it is estimated that 57% of Cerrado is degraded. In this context, the present paper aimed to accomplish a systematic review of the last 10 years which answered the following question: “what are the main methods of restitution of degraded areas in the Cerrado?”. Therefore, the methodology was divided into 5 stages: papers identification in the research platform Google Scholar; title screening to exclude duplicates; variable eligibility; inclusion and analysis. Within the 44 analyzed papers, the biggest amount of publication occurred in 2011. Distrito Federal, Minas Gerais e Mato Grosso do Sul were the states with more publications. The most studied Cerrado physiognomic vegetation was the Cerrado sensu stricto. Active restitution was the most abundant. 80% of the papers were labelled as restoration and the rest as recovery. Based on this study it is conclude that the most used restitution method in the Cerrado degraded areas was the active restoration with drift planting and direct seeding.