Woody Vegetation Types Research Articles

Litter and soil properties under woody and non-woody vegetation types: Implication for ecosystem management in a mountainous semi-arid landscape

There are contrasting reports about whether and how vegetation types influence litter and soil properties. Accurate and comprehensive assessment of the complex relationship between vegetation types, litter and soil characteristics in semi-arid mountain landscapes is almost unknown. Thus, the purpose of this research was to study the effects of (1) Carpinus orientalis Miller., (2) Crataegus melanocarpa M.B., (3) Rhamnus pallasii Fisch. and C.A.Mey, (4) Agropyron longiaristatum Boiss, (5) Bromus tomentolus Bioss. and (6) Hordeum vulgare L. on litter properties and soil physical, chemical, biochemical and biological features in northern Iran. A sampling of the organic layer (litter) and mineral soil (30 × 30 cm) from a depth of 0–10 cm was done for all characteristics in the summer season and for soil microclimate and biological characteristics in the summer and fall seasons. A total of 90 litter samples, 90 soil samples in summer and 90 soil samples in fall (6 vegetation types × 2 seasons × 15 samples) were taken from the area and transferred to the laboratory. Results showed that the Carpinus improved litter properties, soil organic matter contents, total N and available nutrients (P, K, Ca and Mg) and enzyme activities (urease, acid phosphatase, arylsulfatase and invertase). In addition, the population of earthworm groups (epigeic, anecic, and endogeic), acarina, collembola, nematodes, protozoa (especially in the fall season) and bacteria and fungi (especially in the summer season) under Carpinus significantly increased. Data analysis demonstrated higher soil fertility and biological activities in the woody vegetation, which can be assigned to the higher litter input and nutrients. Overall, the findings of this study showed that woody vegetation, especially Carpinus, can improve soil properties at high altitudes of mountainous, semi-arid sites that are often considered as especially fragile and sensitive ecosystems.

Rural land cover mapping using short-term Sentinel-2 temporal composites and machine learning

Multispectral sensors have been invaluable for land cover mapping. Nonetheless, cloud cover is frequent in many parts in the tropics, meaning that relying on single-date multispectral data can be problematic. The limited number of variables, i.e., only two, in conventional dual-polarized synthetic aperture radar data usually drives low classification accuracies. Researchers have explored an augmentation strategy that uses textural features, such as Haralick’s Gray Level Co-occurrence Matrix and/or decomposition features. However, this also does not produce an acceptable outcome. Another approach involves short-term temporal stacking. This masks out atmospheric disturbance and means every pixel has a single value representing the object. Our research explored this last approach to identify woody vegetation in a rural area of Indonesia from Sentinel-2 data. Ten machine learning algorithms were explored to investigate limitations and opportunities. We investigated algorithms capable of reporting variable importance to indicate crucial spectral bands. This study indicated that highly important spectra include red edge and short-wave infrared bands and to a lesser extent, the red band. Part of these bands were confirmed by the variable importance. The spectral similarity between bands 8 and 8A could be seen as a drawback when both bands are employed. Variable importance indicated a negative impact due to this similarity, suggesting that only one should be used in the classification. Overall, classification accuracy was generally high (over 96%), except in the case of the benchmark, i.e., classification and regression trees. Highest accuracy (97.6%) was provided by C5.0 model, although the difference from random forests (RFs) was negligible. The RF was favored as it produced a better estimate of timber plantations. A few algorithms were unable to separate woody vegetation types, including the popular support vector machine. Successful separation was mainly achieved by ensemble tree learners, such as RFs and the variants of extreme gradient boosting.

Habitat associations and conservation opportunities for priority birds on small, diversified farms in the northeastern USA

Abstract Although the impacts of intensive agriculture on biodiversity and strategies for mitigating these effects have been widely described, small-scale, diversified farms and the opportunities they present for bird conservation have been less thoroughly examined. This omission is potentially significant, because this form of agriculture represents a growing sector of the industry in the populous northeastern USA, and the diverse habitats on these farms contrast with larger, structurally homogeneous intensive agriculture. To evaluate bird-habitat associations and conservation opportunities for supporting species of conservation concern on these small, diversified farms, we conducted avian point count and vegetation surveys across 23 farms in western Massachusetts during the summers of 2017 and 2018. We used Poisson-binomial mixture models and canonical correspondence analysis to assess the effects of a suite of microhabitat-, field- and landscape-scale (1 km buffer around the field) variables on the abundance of bird species. Our results confirmed that shrubland birds, a group of species of elevated conservation concern, accounted for 52% of the total observations, including song sparrow (Melospiza melodia), gray catbird (Dumatella carolinensis), common yellowthroat (Geothlypis trichas) and American goldfinch (Spinus tristis). Species–habitat relationships were diverse; however, smaller field sizes, and increased cover of tall, dense, woody or non-productive vegetation types were associated with higher abundance of shrubland species as well as lower abundance of crop pests such as European starling (Sturnus vulgaris) and house sparrow (Passer domesticus). These findings support the hypothesis that small, diversified farms are supporting birds of high conservation concern, and we provide species-specific guidelines for farmers interested in conserving birds on their land.

El Cerro de La Virgen, Culiacán, Sinaloa como propuesta de área natural protegida: conservando los bosques secos

The municipality of Culiacán, Sinaloa, México, does not have Natural Protected Areas (ANP) under municipal decree and, since 2004, lacks an ANP to protect its dry forest. Within state normative, it manages the Tacuichamona mountain range, shared by the municipalities of Cosalá and Elota, enacted in 2020. The current study aims to describe woody plant richness, risk categories, vegetation types, and conservation status of the Cerro de la Virgen, Culiacán, Sinaloa. INEGI’s cartography was consulted with an available 1:1 000 000 and 1:250 000 scale to describe the geographic location, and the physical and biological variables, resulting in a BS1 (h´)w climate, with its geology composed of andesite-andesite tuff, ignimbrite- rhyolite tuff, granodiorite, and alluvium; vertisol soil with tropical deciduous forest vegetation and secondary vegetation. Transects were traced for listing the woody plants, adding 0.1 ha. The in-situ identification was carried out by specialists. To determine the national endangered status, the NOM 059-SERMARNAT-2010 was consulted, together with the International Red List (UICN). It resulted in a richness of 18 families, 49 genera, and 51 species of woody plants. Sitting in the richness range of taxa described by Gentry (Between 50 and 70 species) for tropical dry forests in America. The family with the highest quantity of genera was Fabaceae, and the genus with the highest richness was Bursera. Regarding the extinction risk status from the national legislation, four species were registered: Two under Special Protection (Pr) and two under the Threatened status (A). According to IUCN, a total of 40 species are counted. It is required to issue more decrees to compensate for deforestation by land-use change. For this reason, the decree of the Cerro de la Virgen as an ANP Will increase the conservation cover in 914.83 ha of dry forest of Sinaloa México. Partially amending the loss of vegetation surface in forests and jungles. Additionally, it would shelter multiple environmental, ecological and cultural services that dry forests provide, materializing the conservation jurisprudence of natural areas and would support international organizations' conservation efforts for 2030.

Improving Estimation of Woody Aboveground Biomass of Sparse Mixed Forest over Dryland Ecosystem by Combining Landsat-8, GaoFen-2, and UAV Imagery

Sparse mixed forest with trees, shrubs, and green herbaceous vegetation is a typical landscape in the afforestation areas in northwestern China. It is a great challenge to accurately estimate the woody aboveground biomass (AGB) of a sparse mixed forest with heterogeneous woody vegetation types and background types. In this study, a novel woody AGB estimation methodology (VI-AGB model stratified based on herbaceous vegetation coverage) using a combination of Landsat-8, GaoFen-2, and unmanned aerial vehicle (UAV) images was developed. The results show the following: (1) the woody and herbaceous canopy can be accurately identified using the object-based support vector machine (SVM) classification method based on UAV red-green-blue (RGB) images, with an average overall accuracy and kappa coefficient of 93.44% and 0.91, respectively; (2) compared with the estimation uncertainties of the woody coverage-AGB models without considering the woody vegetation types (RMSE = 14.98 t∙ha−1 and rRMSE = 96.31%), the woody coverage-AGB models stratified based on five woody species (RMSE = 5.82 t∙ha−1 and rRMSE = 37.46%) were 61.1% lower; (3) of the six VIs used in this study, the near-infrared reflectance of pure vegetation (NIRv)-AGB model performed best (RMSE = 7.91 t∙ha−1 and rRMSE = 50.89%), but its performance was still seriously affected by the heterogeneity of the green herbaceous coverage. The normalized difference moisture index (NDMI)-AGB model was the least sensitive to the background. The stratification-based VI-AGB models considering the herbaceous vegetation coverage derived from GaoFen-2 and UAV images can significantly improve the accuracy of the woody AGB estimated using only Landsat VIs, with the RMSE and rRMSE of 6.6 t∙ha−1 and 42.43% for the stratification-based NIRv-AGB models. High spatial resolution information derived from UAV and satellite images has a great potential for improving the woody AGB estimated using only Landsat images in sparsely vegetated areas. This study presents a practical method of estimating woody AGB in sparse mixed forest in dryland areas.

Floristic and structural diversity of woody vegetation in the Sudano-guinean zone of Larmanaye, Chad

This study was carried out in the Larmanaye ecological landscape in the Sudano-guinean zone of Chad. The objective was to analyse the floristic and structural diversity of different woody-vegetation types. Floristic and dendrometric data were collected in 92 plots of 2500 m² to assess woody species with diameter greater than 5 cm, and 460 plots of 25 m² for the assessment of regeneration. The composition, diversity, diameter and height structure, density, species and family importance value of the woody species were described, evaluated and compared among vegetation types. A total of 80 species belonging to 63 genera and 25 families were recorded with 64, 61, 52 and 46 species respectively in tree-based savannah, gallery forest, croplands, and shrubby savannah. The families of Fabaceae and Combretaceae were the richest and abundant in the all woody-vegetation types. Shannon diversity index varied from 3.23 in the gallery forest to 2.72 in the tree-based savannah whereas the Pielou evenness index varied from 0.95 in the tree-based savannah to 0.91 in croplands. The distribution of stems of the main species in classes of diameter and height showed an “L” shaped curve. Mean density varied from 24.70 stems/ha in the tree based savannah to 9.65 stems/ha in the shrubby savannah. The levels of regeneration were low with seedlings proportion of 18.75, 15.83, 10.05 and 9.18%, respectively in croplands, tree-based savannah, gallery forest and shrubby savannah. Protection systems and appropriate management were therefore recommended in order to ensure the sustainability of the forest resources in Larmanaye ecological landscape. Key words: Floristic diversity, Larmanaye-Chad, regeneration, structure, woody vegetation type.

Monitoring long-term riparian vegetation trends to inform local habitat management in a mountainous environment

Riparian ecosystems provide critical habitat for many species, yet assessment of vegetation condition at local scales is difficult to measure when considering large areas over long time periods. We present a framework to map and monitor two deciduous cover types, upland and riparian, occupying a small fraction of an expansive, mountainous landscape in north-central Wyoming. Initially, we developed broad-scale predictions of predominant woody vegetation types by integrating Landsat data into species distribution models and combining subsequent outputs into a synthesis map. Then, we evaluated a 35-year Landsat time series (1985–2019) using the Mann-Kendall test to identify significant trends in the condition of upland and riparian deciduous vegetation and assessed the rate and direction of change using the Theil-Sen estimator. Finally, we used plot level data to assess the utility of the framework to detect bottom-up controls (ungulate browse pressure and management actions) on vegetation condition. The synthesis map had an overall correct classification rate of 87% and field data indicated deciduous vegetation within 45 m of coniferous forest faces increased pressure of conifer expansion. The trend assessment identified consistent patterns operating at the landscape scale across both upland and riparian deciduous vegetation; a predominant greening trend was observed for 12 years followed by a 9-year browning trend, before switching back to a greening trend for the last 13 years of the study. Our results indicate trends are driven by the climate of the measurement period at the landscape scale. Although we did not find conclusive evidence to establish a strong link between browse pressure and satellite data, we highlight examples where prevailing trends can be overridden by local disturbance or management intervention. This framework is transferable to other understudied riparian environments throughout western North America to provide insight on ecohydrological processes and assess global and local stressors across broad spatiotemporal scales.

Using Sentinel-2 and canopy height models to derive a landscape-level biomass map covering multiple vegetation types

Vegetation biomass is a globally important climate-relevant terrestrial carbon pool and also drives local hydrological systems via evapotranspiration. Vegetation biomass of individual vegetation types has been successfully estimated from active and passive remote sensing data. However, for many tasks, landscape-level biomass maps across several vegetation types are more suitable than biomass maps of individual vegetation types. For example, the validation of ecohydrological models and carbon budgeting typically requires spatially continuous biomass estimates, independent from vegetation type. Studies that derive biomass estimates across multiple vegetation or land-cover types to merge them into a single landscape-level biomass map are still scarce, and corresponding workflows must be developed. Here, we present a workflow to derive biomass estimates on landscape-level for a large watershed in central Chile. Our workflow has three steps: First, we combine field plot-based biomass estimates with spectral and structural information collected from Sentinel-2, TanDEM-X and airborne LiDAR data to map grassland, shrubland, native forests and pine plantation biomass using random forest regressions with an automatic feature selection. Second, we predict all models to the entire landscape. Third, we derive a land-cover map including the four considered vegetation types. We then use this land-cover map to assign the correct vegetation type-specific biomass estimate to each pixel according to one of the four considered vegetation types. Using a single repeatable workflow, we obtained biomass predictions comparable to earlier studies focusing on only one of the four vegetation types (Spearman correlation between 0.80 and 0.84; normalized-RMSE below 16 % for all vegetation types). For all woody vegetation types, height metrics were amongst the selected predictors, while for grasslands, only Sentinel-2 bands were selected. The land-cover was also mapped with high accuracy (OA = 83.1 %). The final landscape-level biomass map spatially agrees well with the known biomass distribution patterns in the watershed. Progressing from vegetation-type specific maps towards landscape-level biomass maps is an essential step towards integrating remote-sensing based biomass estimates into models for water and carbon management.

The lowland seasonally dry subtropical forests in central Argentina: vegetation types and a call for conservation

Aims: The native woody vegetation from the Espinal phytogeographic province in central Argentina, found in subtropical-warm temperate climates, represents part of the southernmost seasonally dry forest in South America. Although this vegetation has been studied for over a century, a complete phytosociological survey is still needed. This lack of knowledge makes its spatial delimitation and the establishment of efficient conservation strategies particularly difficult. The main goals of this study were to classify these forests and assess their current forest cover and to better define the extent of the Espinal phytogeographic province in Córdoba region, central Argentina. Study area: Espinal Phytogeographic Province in Córdoba region, central Argentina (ca. 101,500 km2). Methods: We sampled 122 stands following the principles of the Zürich-Montpellier School of phytosociology; relevés were classified through the ISOPAM hierarchical analysis. The extent of the Espinal phytogeographic province was established by overlaying previous vegetation maps, and a map showing the current distribution of forest patches was constructed based on a supervised classification of Landsat images. Results: Four woody vegetation types of seasonally dry subtropical forest were identified based on the fidelity and the abundance of diagnostic species: (1) Aspidosperma quebracho-blanco forest; (2) Zanthoxylum coco forest; (3) Geoffroea decorticans forest; and (4) Prosopis caldenia forest. These vegetation types were segregated along gradients of temperature and precipitation seasonality and soil-texture and sodium content. The remaining forest patches represent 3.43% of the extent of the Espinal province in Córdoba region of which only 1.05% is represented in protected areas. Conclusions: We present a classification of the Espinal forest based on a complete floristic survey. Despite the dramatic forest loss reported, our results show that some forest patches representative of the Espinal are still likely to be found in the area. However, urgent measures should be taken to establish new protected natural areas in order to preserve the last remaining forest patches. Taxonomic reference: Catálogo de las Plantas Vasculares del Cono Sur (Zuloaga et al. 2008) and its online update (http://www.darwin.edu.ar). Abbreviations: ISOMAP = isometric feature mapping; ISOPAM = isometric partitioning around medoids.

Typology of the woody plant communities of the Ethiopian Nech Sar National Park and an assessment of vegetation-environment relations and human disturbance impacts

Background and aims – Deforestation and forest degradation have hugely affected the Southern Ethiopian Rift Valley, jeopardizing biodiversity conservation and ecosystem service provisioning. Quantifying the impacts of human activities on the remaining woody plant communities and recognizing vegetation–environment relationships provide the basis for targeted conservation and rehabilitation.Material and methods – The study was performed in the Nech Sar National Park (NSNP). Based on a large systematic vegetation survey of 104 plots, we quantified the woody vegetation composition, and we provided a vegetation classification based on Non Metric Multidimensional Scaling, cluster analysis and indicator species analysis. Furthermore, we evaluated vegetation – environment relationships and the effects of human disturbance on community composition and woody plant species richness and diversity.Key results – Our analyses revealed three very distinct woody vegetation types (Acacia mellifera-Combretum aculeatum; Lecaniodiscus fraxinifolius-Deinbollia kilimandscharica and Acacia polyacantha-Ficus sycomorus) which were significantly differentiated by soil pH, electrical conductivity, available soil phosphorus and organic matter, and by elevation. Human disturbance, as quantified by a compound Human Disturbance Index (HDI) significantly affected community composition, species richness and diversity, and was significantly positively correlated with species richness and diversity. The latter is likely due to intermediate levels of disturbance and encroachment of disturbance affiliated shrubs such as Dichrostachys cinerea, Lantana camara, and Acalypha fruticosa. Furthermore, the demographic structure of key woody species such as Acacia polyacantha, Acacia tortilis, Balanites aegyptiaca, Diospyros abyssinica, Lecaniodiscus fraxinifolius and Terminalia brownii, showed impacts of human disturbance.Conclusion – Our results provide a baseline for further conservation actions in the NSNP which should be differentially targeted on the different plant community types. Overall, human disturbance seems not to have resulted yet in species richness declines, although it has started to affect the integrity of the delineated vegetation types and resulted in small scale succession.

Integrating Species‐Specific Information in Models Improves Regional Projections Under Climate Change

AbstractModels commonly used to project forest carbon response to climate change reduce biodiversity to a small number of plant functional types or plant functional traits for the sake of computational efficiency at large spatial scales. We simulated the climate sensitivity of the dominant woody vegetation types in New Mexico using both a generalized functional type and a species‐specific model parameterization. Both parameterizations achieve reasonable current carbon uptake rates and aboveground biomass amount at the ecosystem scale. When vegetation types are subjected to increasing temperature and decreasing precipitation, the generalized parameterization differs substantially from the species‐specific parameterization by homogenizing the diversity of adaptations for dealing with higher temperature and drought, leading to divergent responses under changing climate. We recommend integrating species‐specific information, when available, to improve projections of climate change impacts on forested ecosystems to develop robust ecosystem management strategies at regional scales.

Vegetation changes over the past two decades in a West African savanna ecosystem

AbstractQuestionsWest African savanna ecosystems are affected by increasing land use intensity (e.g., agriculture and livestock herds) due to a growing human population. To understand the impact of land use intensification on savanna vegetation, we aim to answer the following questions: How do savanna species composition, diversity and structure change with increasing land use pressure? Are the impacts of land use change different in the woody and the herbaceous layers? Do the effects of land use change differ between vegetation types?LocationSoutheastern Burkina Faso, West Africa.MethodsVegetation plots from the early 1990s representing vegetation types occurring in fallows of different age and in uncultivated pasturing zones were resurveyed. We distinguished between woody (tree and shrub layer) and herbaceous vegetation types. Species composition changes were analyzed using ordination techniques (detrended correspondence analysis, DCA) and indicator species analysis (IndVal). Species turnover and plant diversity as represented by species richness and evenness were compared between the baseline survey and the resurvey.ResultsIn most woody vegetation types, we found no change in species composition and richness over the past two decades. However, some highly valued woody species decreased in abundance. In contrast, in most herbaceous vegetation types, species composition changed considerably and species richness increased. The proportion of wide‐ranging, ruderal herbaceous species increased, indicating a homogenization of herbaceous vegetation types, while preferred fodder herbaceous species decreased. We assume that the increased grazing intensity over the past two decades is the driver of these changes in the herbaceous layer.ConclusionsOur results show different reactions of vegetation types and layers to land use intensification and reinforce the need for studies on the basis of vegetation type that incorporate both the herbaceous and the woody layers.

Non-Forest Woody Vegetation (Scattered Greenery) Case Study of the Samopse Settlement, Czech Republic

The development and management of the Czech landscape has been influenced by several key factors in the past. One important factor is the development of society, particularly political changes and ecological development. Others include the level of knowledge and understanding of technologies, scientific knowledge and the non-productive importance of the landscape, as well as the attitude of society and individuals towards the landscape. In the past, non-forest woody vegetation was a standard part of the European agricultural landscape and formed its typical appearance. The onset of collective farming during the second half of the twentieth century resulted in transforming the landscape into open fields without permanent vegetation. The landscape became everyone’s and no-one’s and was subject to orders, tasks and plans. The key goal of this article is to evaluate non-forest woody vegetation from a landscape-ecological aspect and compare the occurrence of non-forest woody vegetation in four landscape types. The submitted study presents various types of non-forest woody vegetation, the species present in elements of scattered greenery and the spatial arrangement depending on the method of management and use of the territory.

Dynamic Vegetation Simulations of the Mid‐Holocene Green Sahara

AbstractThe “Green Sahara” is a period when North Africa was characterized by vegetation cover and wetlands. To qualitatively identify the orbital‐climatic causation of the Green Sahara regime, we performed dynamic vegetation model (LPJ‐GUESS) simulations, driven by climate forcings from coupled general circulation model (EC‐Earth) simulations for the mid‐Holocene, in which the vegetation is prescribed to be either modern desert or artificially vegetated with a reduced dust load. LPJ‐GUESS simulates a vegetated Sahara covered by both herbaceous and woody vegetation types consistent with proxy reconstructions only in the latter scenario. Sensitivity experiments identify interactions required to capture the northward extension of vegetation. Increased precipitation is the main driver of the vegetation extent changes, and the temperature anomalies determine the plant functional types mainly through altered fire disturbance. Furthermore, the simulated vegetation composition also depends on the correct representation of soil texture in a humid environment like Green Sahara.

Optimisation of Savannah Land Cover Characterisation with Optical and SAR Data

Accurately mapping savannah land cover at the regional scale can provide useful input to policy decision making efforts regarding, for example, bush control or overgrazing, as well as to global carbon emissions models. Recent attempts have employed Earth observation data, either from optical or radar sensors, and most commonly from the dry season when the spectral difference between woody vegetation, crops and grasses is maximised. By far the most common practice has been the use of Landsat optical bands, but some studies have also used vegetation indices or SAR data. However, conflicting reports with regards to the effectiveness of the different approaches have emerged, leaving the respective land cover mapping community with unclear methodological pathways to follow. We address this issue by employing Landsat and Advanced Land Observing Satellite Phased Array type L-band Synthetic Aperture Radar (ALOS PALSAR) data to assess the accuracy of mapping the main savannah land cover types of woody vegetation, grassland, cropland and non-vegetated land. The study area is in southern Africa, covering approximately 44,000 km2. We test the performance of 15 different models comprised of combinations of optical and radar data from the dry and wet seasons. Our results show that a number of models perform well and very similarly. The highest overall accuracy is achieved by the model that incorporates both optical and synthetic-aperture radar (SAR) data from both dry and wet seasons with an overall accuracy of 91.1% (±1.7%): this is almost a 10% improvement from using only the dry season Landsat data (81.7 ± 2.3%). The SAR-only models were capable of mapping woody cover effectively, achieving similar or lower omission and commission errors than the optical models, but other classes were detected with lower accuracies. Our main conclusion is that the combination of metrics from different sensors and seasons improves results and should be the preferred methodological pathway for accurate savannah land cover mapping, especially now with the availability of Sentinel-1 and Sentinel-2 data. Our findings can provide much needed assistance to land cover monitoring efforts to savannahs in general, and in particular to southern African savannahs, where a number of land cover change processes have been related with the observed land degradation in the region.

Native woody vegetation in central Argentina: Classification of Chaco and Espinal forests

AbstractQuestionWhat are the composition and spatial patterns of native woody plant communities in the southern Great Chaco and Espinal?LocationCórdoba Province, central Argentina, an area of ca. 161,000 km2.MethodsWe collected 351 geo‐referenced relevés representative of the geographic, topographic and ecological variation of the Chaco and Espinal woody vegetation in central Argentina. The relevés were classified into vegetation types using the hierarchical ISOPAM method. Forest and shrubland types were described on the basis of diagnostic species occurrences and their distribution in relation to environmental factors. A map of the actual vegetation derived from remote‐sensed images (Landsat) and field data was used to describe the current distribution and abundance of the different vegetation types.ResultsThe classification of the 351 plots × 837 species matrix revealed two major clusters comprising seven woody vegetation types corresponding to Chaco lowland and mountain forests and shrublands, Espinal forests and edaphic vegetation. The most important gradients in woody vegetation types are related to elevation, temperature and rainfall variables.ConclusionsSubtropical seasonally dry woody plant communities from the southern extreme of the Great Chaco and Espinal forests were described for the first time based on complete floristic data. Our results show that lowland Chaco native forests, as well as replacement communities, are still present in its southern distribution range and are well distinguishable from other vegetation types such as the Espinal and mountain forests. Overall, extensive Espinal forests have almost disappeared while Chaco vegetation is highly fragmented and degraded.

The persistent decline of patterned woody vegetation: The tiger bush in the context of the regional Sahel greening trend.

Following 25years of below average annual rainfall in the Sahel between 1970 and 1995, the return to more humid conditions has led to rapid postdrought recovery of the woody cover. However, the increase in the woody cover is not spatially homogeneous raising questions about the resilience of some woody vegetation types. Based on the analysis of field and remote sensing data collected on the tiger bush systems in the northern Sahel in Mali, this study noted the current and persistent degradation of these systems in the Sahel since the 1970s despite the recent improvement in rainfall since the mid-1990s and the general Sahel re-greening. Profound changes in the woody population pattern, tree density and cover, and floristic composition took place regardless of the site location along the south-north rainfall gradient. Associated with definite structural changes of the woody population, surface hydrology shifted from a sheet to concentrated run-off accelerating the collapse of the patterned woody population. Currently, there is no evidence in favour of reversing the current degradation process, at least at a decadal scale, although very sparse recolonization by pioneer woody vegetation has been observed in the driest sites along recently formed gullies. These observations support the hypothesis of an ecosystem shift, with long-term implications for the structure and functioning of the patterned vegetation, as well as the whole watershed landscape through increased run-off leading to stronger water flows in enlarged wadis, increased soil erosion upstream and sediment deposition downstream, enhanced water storage in ponds, and greater recharge of aquifers, which is an illustration of the "Sahelian paradox".

The hidden role of woody debris stocks as a woodfuel source: why cutting down trees if woodfuel can be gathered from forest floor?

SUMMARY: Recently, the key role played by woody debris within the ecological dynamics of forest ecosystems has been acknowledged; however, its contribution as a source of woodfuel has barely been studied, despite being the most important energy resource for one-third of world population. Over decades, the widely held belief that woodfuel exclusively comes from woody living biomass has labelled woodfuel collection as a driver of tropical deforestation. The poor understanding about gathering ways of this resource in the rural developing world has hidden the fact that it is mainly sourced from woody necromass, of which their stocks and productivity may be estimated at 35 Pg and 6.5 Pg year-1 in tropical forests, respectively. Whether necromass productivity of both geographically accessible tropical forest for rural communities and other types of woody vegetation is taken into account together, a potential supply of 2.19 Pg year-1 could be estimated, which would meet by far, the projected global rural woodfuel demand. It concludes that household-oriented woodfuel collection is far from being a driver of deforestation; instead, this latter might jeopardize access to this energy source. This paper tries to provide a new insight about the relationship between rural energy security and forest-based ecosystem services and their repercussions on climate change.

Zmeny spoločenstiev bystruškovitých rôznych typov habitatov poľnohospodárskej krajiny v závislosti od vybraných environmentálnych faktorov vrátane pôdnych vlastností

The variations in ground beetles (Coleoptera: Carabidae) assemblages across the three types of farmland habitats, arable land, meadows and woody vegetation were studied in relation to vegetation cover structure, intensity of agrotechnical interventions and selected soil properties. Material was pitfall trapped in 2010 and 2011 on twelve sites of the agricultural landscape in the Prešov town and its near vicinity, Eastern Slovakia. A total of 14,763 ground beetle individuals were entrapped. Material collection resulted into 92 Carabidae species, with the following six species dominating: Poecilus cupreus, Pterostichus melanarius, Pseudoophonus rufipes, Brachinus crepitans, Anchomenus dorsalis and Poecilus versicolor. Studied habitats differed significantly in the number of entrapped individuals, activity abundance as well as representation of the carabids according to their habitat preferences and ability to fly. However, no significant distinction was observed in the diversity, evenness neither dominance. The most significant environmental variables affecting Carabidae assemblages species variability were soil moisture and herb layer 0-20 cm. Another best variables selected by the forward selection were intensity of agrotechnical interventions, humus content and shrub vegetation. The other from selected soil properties seem to have just secondary meaning for the adult carabids. Environmental variables have the strongest effect on the habitat specialists, whereas ground beetles without special requirements to the habitat quality seem to be affected by the studied environmental variables just little.

Endemism and geographic distribution of African Thismiaceae

Background and aim – The occurrence of the enigmatic plant family Thismiaceae has never been characterized in detail, but appears to be focused in three vegetation types. This study used data from the literature, in tandem with detailed new field data from Cameroon, to document, map, and predict potential distributions of Thismiaceae species across Africa, and relate their occurrence to features of climate.Methods – We reviewed known occurrences of Thismiaceae species across Africa; in Cameroon, Thismiaceae occurrences were studied in 22 1-ha plots (220 000 m 2 ), at lowland, sub-montane, and montane sites in evergreen forest, semi-deciduous forest, and woody and grassland savannah vegetation types. Assembling known occurrences from across the continent, ecological niche modeling was used to map potential geographic ranges of African Thismiaceae under present-day climate conditions across Africa.Results and discussion – In Cameroon fieldwork, 338 individual Thismiaceae were recorded, corresponding to eleven species of Afrothismia. The most occupied vegetation type for Thismiaceae was sub-montane forest. Occurrence of Thismiaceae seems to depend principally on rainfall, as most specimens were recorded in areas with high rainfall, about six weeks after the first rains, toward the middle or end of the rainy season. This pattern seems to be consistent across all of the species. Soil analyses shows that Afrothismia was most frequent under conditions of low calcium (0.09–15.21 %) and pH of 3.58–6.16. Niche models predicted that additional Thismiaceae populations may be discovered at high-rainfall sub-montane forest sites in Democratic Republic of Congo, Rwanda, Tanzania, and Kenya. Across tropical Africa, the Thismiaceae comprise 22 species in two genera (twenty Afrothismia and two Oxygyne ), recorded from seven countries. Many of these species are narrowly endemic to one or a few specific sites, so that detailed knowledge of distributional patterns is important for their conservation.