Main Ecological Factors Research Articles

Topological differentiation of vegetation of the Lublin-Volyn geobotanical district

The position of the Lublin and Volyn (Volhynian) uplands within the geobotanical zonation system is ambiguous and disputable. An analysis of the syntaxonomical diversity and landscape distribution of the egetation of the Lublin and Volyn uplands revealed their similarity, and we consider this whole territory as the Lublin-Volyn geobotanical district of hornbeam-oak, oak forests, and steppe meadows. This district differs from the adjacent territories and is classified within the Central European mixed forests ecoregion. Typical and diagnostic syntaxa have been identified, and ecological-coenotic profiles have been constructed to characterize the distribution patterns of shrub-forest and herbaceous vegetation within the landscape. Based on calculations of phytosociological indicators for the main ecological factors, graphical patterns of their variation were developed. It was determined that the characteristic forests of the district, Tilieto-Carpinetum (Carpinion betulis), are represented by four variants (T.-C. var. galeobdolosum; T.-C. var. hepaticosum; T.-C. var. caricosum pilosae; T.-C. var. isopyrosum). The district is also characterized by the presence of syntaxa associated with carbonate soils, both of the marsh type (Caricion davallianae) and the meadow-steppe type (Cirsio-Brachypodion, Festucion valesiacae), with the dominance of Carex humilis and Stipa capillata. Using DCA-analysis, the correlation between ecological factor indicators and the distribution of plant communities within the ecological space has been established, forming six fields distributed along three vectors: by moisture (aquatic and marsh communities), xerophytism, and chemical properties of soils (meadow-steppe communities), as well as the structure of coenoses with a specific ombroregime (forest communities).

Determination and Ecological Risk Assessment of Quinolone Antibiotics in Drinking and Environmental Waters Using Fully Automated Disk-Based SPE Coupled with UPLC-MS/MS.

Quinolone antibiotics (QNs) contamination in the aquatic environment is a global public health issue considering their resistance and mobility. In this study, a simple, efficient, and sensitive method was developed for the accurate quantification of fifteen QNs in water using automated disk-based solid-phase extraction (SPE) coupled with ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). By utilizing a 3M SDB-XC disk to enrich QNs from a 1000 mL water sample, the detection limits were improved to 0.008-0.055 ng/L due to the satisfactory enrichment factors of 897-1136, but only requiring about 60 min per six samples. The linearity of the method ranged from 0.05 to 100 μg/L for the 15 QNs, with correlation coefficients of 0.9992-0.9999, and the recoveries were in the range of 81-114%, with relative standard deviations of 0.2-13.3% (n = 6). The developed method was applicable for the quantification of trace QNs at low ng/L levels in drinking and environmental waters. The results showed that no QNs were detected in tap water, while three and four QNs were detected in the river water of Zhoushan and the seawater of Daiquyang and Yueqing Bay, East China, respectively, with a total concentration of 1.600-8.511 ng/L and 1.651-16.421 ng/L, respectively. Among the detected QNs, ofloxacin (OFL) was the predominant compound in river water, while enrofloxacin (ENR) was predominant in seawater. The risk quotient (RQ) results revealed that QNs posed a low risk to crustaceans and fish, but a low-to-medium risk to algae, and OFL presented the main ecological risk factor in river water, while ENR and CIP in seawater. Overall, the proposed automated disk-based SPE-UPLC-MS/MS method is highly efficient and sensitive, making it suitable for routine analysis of QNs in drinking and environmental waters.

Masks Versus Cattle: The Ecology of an African Art Form

Masquerades form an important part of indigenous African religions, and headpieces of masks are found all over the world as an iconic African art form. Contrary to expectation, however, the geographical distribution of masking is very restricted, occurring only in three areas of the continent, mainly situated in the forested zones. I explain this peculiar distribution by tracing the ecological and historical parameters of the societies that harbor mask rituals. The main ecological factors are the absence of cattle and the type of horticulture, while a crucial historical element is the long history of slave raiding and trading to which the continent has been subjected. These factors have led to societies in which both gender and local power arrangements show a marked indeterminacy, operating as internal arenas between men and women, and between different groups of men. Crucial in the explanation of masquerades is the fact that masking is completely absent from societies that practice cattle husbandry with the Bos indicus species (zebu). Since sleeping sickness prohibits cattle husbandry, wherever the tsetse fly thrives, masks appear.

Identification of geographic, climatic, and soil factors dominating Stevia rebaudiana yield and quality

Raising crop yields and quality through plant ecological research has become an important approach to sustainably improving crop products. Stevia rebaudiana is widely introduced and cultivated around the world because of the continuous increase in demand for steviol glycosides. When selecting regions or plots suitable for high-yield and high-quality cultivation, it is necessary to understand the main ecological factors that contribute to the formation of S. rebaudiana yield and quality. In this study, sampling plots from different geographic and climatic regions in Xinjiang and Jiangsu were selected for S. rebaudiana cultivation. The geographic, climatic and soil ecological factors were analyzed based on a PLSR (partial least squares regression) model to discover the potentially influential factors in the yield and quality formation of the crop. The results suggest that not all geographic and climatic ecological factors contributed to yield formation; however, these factors, such as latitude, altitude and annual sunshine duration, had high or moderate influences on the concentration of each steviol glycoside and total steviol glycoside. Soil organic matter (OM), total potassium (TK), available potassium (AK), zinc (Zn), and catalase (CAT) had high or moderate effects on the concentrations of each steviol glycoside and total steviol glycoside. However, the other soil factors showed variability in the extent to which they drove the steviol glycosides. The study contributes to a more profound understanding of the ecological driving mechanisms of S. rebaudiana yield and quality formation. The yield or steviol glycoside concentrations of sweetleaf may be improved by modifying certain key ecological factors.

Farming practices, varietal preferences, and land suitability analyses for yam production in Eastern D.R. Congo: implications for breeding initiatives and food sovereignty

Yam (Dioscorea spp.) is a key tuber crop in sub-Saharan Africa (SSA) with huge potential for poverty alleviation, food sovereignty, and nutrition security. Exploiting its full potential requires that factors holding it down are understood and mitigated. This study, conducted between May and July 2022 and 2023, assessed yam farming practices, varietal preferences, and land suitability in the Eastern Democratic Republic of Congo (DRC). We interviewed 765 smallholder farmers within four agro-ecological zones (AEZ) to assess the sociocultural, agronomic, varietal, and biophysical factors affecting yam production. Land suitability analyses were conducted using the Analytic Hierarchy Process (AHP) to identify areas suitable to extensive yam production and to cluster environments that could optimize yam varietal selection and testing. Results showed that yam is mainly cultivated by women in eastern DRC (70%). The seed delivery system is informal, relying primarily on farmer-saved seeds and farmer-seed exchanges (74.9%). Soil depletion (68.3%), limited access to high-quality seeds (54.5%), youth disengagement in yam value chain (50.3%), insect pests (17.9%), and short tuber shelf-life (65.8%) were, respectively, the main ecological, agronomic, sociocultural, biological, and tuber quality factors hindering yam production in eastern DRC. However, the perceived importance of most factors significantly varied with farmer gender and age categories. A multitude of varietal traits was used to assess yam varieties in eastern DRC, of which the tuber taste (59%) was the most valued trait regardless of gender and age categories, though it had highest scores among middle-aged adult women. Land suitability analyses discriminated five clusters; the most significant part of the region falling under suitable (27%), highly suitable (24%), and very highly suitable classes (37%). We further discussed how breeding initiatives for delivering yam varieties, suiting local producers’ and end-users’ needs, could unlock the crop’s potential for enhancing food security and wealth creation in eastern DRC. The land suitability map from this study is a valuable decision-making tool in defining priority areas for extensive yam production and varietal selection and testing. This study provided valuable insights on factors affecting yam production and suggested yam breeding as a backbone of a holistic approach seeking to address challenges faced in unlocking the potential for yam production in eastern DRC.

Distribution pattern and influencing factors of bacterial communities in different soil depths of Caragana jubata shurb in Luya Mountain, China.

Soil microorganisms are important components of terrestrial ecosystems, affecting soil formation and fertility, plant growth and stress tolerance, nutrient turnover and carbon storage. In this study, we collected soil samples (humus layer, 0-10 cm, 10-20 cm, 20-40 cm, and 40-80 cm) from Caragana jubata shrubland in Shanxi subalpine to explore the composition, diversity, and assembly of soil bacterial communities at different depths across the soil profile. The results showed that Actinomycota (19%-28%), Chloromycota (10%-36%) and Acidobacteria (15%-24%), and Proteobacteria (9%-25%) were the dominant bacterial phyla. α-diversity of soil bacterial community significantly decreased with the increases of soil depth. Soil bacterial β-diversity varied across different soil depths. Soil pH, water content, and enzyme activity were the main ecological factors affecting the distribution of soil bacterial communities. Soil bacterial communities had more complex interactions in humus layer and 0-10 cm layer. On the whole, soil bacterial communities were dominated by coexistence in C. jubata shrubland, and the soil bacterial community assembly was driven by random process.

Characteristics of Cyanobacteria at Different Stages of Existence of the Kyiv Reservoir

The paper deals with the patterns of Cyanobacteria long-term succession at different stages of existence of the Kyiv Reservoir. The main ecological factors responsible for Cyanobacteria succession include current velocity, hydromorphological characteristics of the reservoir, the content of inorganic nitrogen (primarily of ammonium) and phosphorus, ΣN : P ratio, global climate changes, and the competition with higher aquatic plants in the shallow water zone. The trophic state of the hydroecosystem changed from mesotrophic (at the stage of the non-regulated river) to eutrophic (at the present time) depending on the intensity of Cyanobacteria development. With possible further deterioration of water quality, possible climate changes with an increase in water temperature within the range of even 1-2°C, the intensity of Cyanobacteria development will increase, especially in the pelagic zone of the reservoir, where they have practically no natural biological competitors.

Source apportionment and risk assessment of heavy metals in typical greenhouse vegetable soils in Shenyang, China.

In this study, the concentrations of Cr, Cu, Ni, Pb, Zn, Cd, As, and Hg in the typical greenhouse vegetable soils in Shenyang, Northeast of China, were determined, and the pollution characteristics and primary sources of heavy mental pollution in soil were analyzed. Results showed that the sum of the mean values of eight typical heavy metals in the soil of the greenhouse soils was 219.79 mg/kg. According to the "Chinese Environmental Quality Evaluation Standard for Farmland of Greenhouse Vegetables Production" (HJ/T 333-2006), the concentrations of Cu (33.50 ± 11.99 mg/kg), Cd (0.246 ± 0.156 mg/kg), and Hg (0.214 ± 0.177 mg/kg) exceeded the limit values in 14.29%, 39.29%, and 39.29% of sampling points, respectively. The single factor pollution index and the Nemerow comprehensive pollution index of heavy metal elements showed that most greenhouse soils were at safety, alert, or light pollution levels. The potential ecological risk index (RI = 505.19) showed that 42.86% of the samples were at high or very high risk and Cd and Hg were the main ecological risk factors. Based on the result of correlation analysis, the Positive Matrix Factorization (PMF) differentiated sources of heavy metal pollution in the study area into four components, including fertilizer input, soil parent material, pesticide spraying and raw coal combustion, and plastic film mulching, which accounted for 36.76%, 22.64%, 20.89%, and 19.71%, respectively, of the total sources of heavy metals.

Plant communities on inselbergs in Burkina Faso

The safeguarding and sustainable management of natural resources, particularly plant resources, requires the implementation of conservation strategies. The study of plant communities is an essential tool for monitoring the development of plant formations. The aim of this study was to identify the plant communities on inselbergs of Burkina Faso in West Africa, to provide a database to supporting the sustainable management of the plant resources withing these fragile ecosystems. Stratified and random sampling was carried out on selected inselbergs in different parts of Burkina Faso along a climatic gradient. In the different phytogeographical sectors, inselbergs consist of granite or sandstone. Plant surveys were conducted using 900 m2 plots for the woody stratum and 100 m2 plots for the herbaceous stratum. An exhaustive list of plant species was compiled and an abundance-dominance coefficient for each species was determined. A DCA, through PCord.6, was used to obtain preliminary groups. Indicator species were determined by a Monte Carlo test with p < 0.05 and calculation of the fidelity index (Phi). Diversity indices through the Shannon index and equitability of Pielou were calculated using Pcord.6 to compare plant communities. A total of 12 plant communities were identified for the inselbergs of Burkina Faso, including 9 communities for savannah and 3 communities for monocotyledonous-mats and ephemeral flush vegetation. The main ecological factors governing the distribution of these inselberg plant communities were found to be were found to be climate, soil depth, soil moisture and altitude. In savannah plant communities, the Terminalia laxiflora and Tephrosia nana communities (unit 6) had the highest number (13) of diagnostic species and the highest fidelity (Phi = 0.97) was for Cleome viscosa species in the Acacia tortilis and Aristida kerstingii communities (unit 1). Diagnostic species numbers vary from 6 to 4 in monocotyledonous-mats and ephemeral flush vegetation and the Dopatrium longidens (Phi = 0.76) and Cyperus podocarpus (Phi = 0.75) have the highest fidelity to unit 3. The Shannon diversity index of deep soil plant communities was highest and significantly different from that of the other savannah communities. Concerning the Piélou equitability index, high values were found in all plant groups, reflecting the absence of species dominance and a balance of the different plant groups.Floristically, Afrotrilepis pilosa infestation of inselbergs is common in West Africa. In Burkina Faso, in addition to Afrotrilepis pilosa, 10 other plant species are found specifically on inselbergs. Given the fragility of the ecosystems in which they live, these inselberg species should be protected.

Effect of climate change on hematotoxicity/hepatoxicity oxidative stress, Oncorhynchus mykiss, under controlled conditions.

Described as the 'main ecological factor', temperature, strongly affects the physiological stress responses of fish. In order to evaluate the effects of temperature variations on fish culture and food value chain, the present study was designed as a climate change model. Furthermore, the present study provides a theoretical basis for a better understanding of the mechanisms of the environmentally induced changes. In this direction, we examined the blood physiology and oxidative stress responses induced by temperature variation in the rainbow trout, a temperature-sensitive cold-water fish. The obtained results showed that climate changes promoted the inhibited activities' expressions and the development of potential tissue and hematological defense mechanisms against temperature-induced toxic damage. This study showed that climate change could be a subset of the studies on the stress physiology in aquaculture, which can be developed for new experimental designs and research collaborations. Furthermore, it highlights knowledge gaps to guide future research in this emerging field.

Pollution and Ecological Risk Assessment of Metal Elements in Groundwater in the Ibinur Lake Basin of NW China

Groundwater pollution by metal elements is a serious issue due to its probable risks to the ecosystem and human health. In the present study, 75 groundwater samples were collected from the Ibinur Lake Basin (ILB) of NW China. The contents of As, Se, Pb, Cu, Cr(Ⅵ), Zn, Mn, and Cd were determined. The levels, pollution degrees, and potential ecological risks of metals in groundwater were systematically analyzed for the first time in this area. The potential sources of metals were also discussed. It was observed that the mean contents of metals in groundwater in the ILB were lower than the Class III thresholds of the Standard for Groundwater Quality of China (GB/T 14848–2017), whereas the maximum contents of As, Se, Pb, Cr(Ⅵ), and Mn exceeded the Class III thresholds values. The pollution index of each metal and the Nemerow comprehensive index (NPI) caused by the overall pollution by all these metals in groundwater showed the pollution-free level. The single and comprehensive potential ecological risk index of analyzed metals in groundwater showed a relatively low level of potential ecological risk. Additionally, spatial distribution patterns of contents, pollution levels, and ecological risks of metals in groundwater in the ILB were found to be substantially heterogeneous. Furthermore, As and Se in groundwater originated from anthropogenic sources such as agriculture and mining, whereas Mn mainly originated from natural factors, and Pb, Cu, Cr(Ⅵ), Zn, and Cd were correlated with both natural and anthropogenic sources. Overall, As was identified as the main pollution factor, while As and Se were identified as the main ecological risk factors in the groundwater in the ILB. These results can provide important information for groundwater management in the ILB and will guide authorities in taking the necessary measures to ensure the safety of groundwater supply in the northwestern arid regions of China.

Effects of main ecological factors on the growth of marine green alga Caulerpa sertularioides using the response surface methodology

Effects of main ecological factors on the growth of marine green alga Caulerpa sertularioides using the response surface methodology

Nesting Habitat Suitability of the Kentish Plover in the Arid Lands of Xinjiang, China.

Understanding the main ecological factors of the nesting habitat of shorebirds is of great significance in relation to their protection and habitat management. Habitat loss and change due to a lack of water threaten the biodiversity of shorebirds, with impacts likely to be most pronounced in arid lands. We collected the data of 144 nesting sites and 10 ecological factors during the breeding season from April to July each year in 2019 and 2020 in nine river districts in Xinjiang. The MaxEnt model was applied to assess the suitability of nesting habitats for Kentish plovers (Charadrius alexandrinus) in the study area to examine the main factors affecting their nesting habitat. The most suitable nesting habitats are mostly distributed in plain reservoirs in the middle part of the Northern Slope of the Tianshan Mountains, Ebinur Lake and its eastern position in the southwestern Junggar Basin, near Ulungur Lake of the Ulungur river area and the southern Irtysh river area. The distance from water, normalized difference vegetation index, mean temperature of the breeding season, slope, and land use were the main factors affecting the nesting habitat selection of Kentish plovers. It was found that the proportion of suitable nesting habitat protected for the Kentish plovers in the study area was low (851.66 km2), accounting for only 11.02% of the total suitable nesting habitat area. In view of the scarcity and importance of water bodies in arid lands and the lack of protection for Kentish plovers at present, it is suggested to strengthen the conservation and management of the regional shorebirds and their habitats by regulating and optimizing the allocation of water resources.

Effect of climate change on fillet quality and shelf-life of Oncorhynchus mykiss under controlled conditions.

Temperature, which affects numerous physiological processes, has been described as the 'main ecological factor' for fish. The aim of this modeling study is to explore the impact of climate-induced temperature changes on fish fillet quality and shelf life. Temperature stress in rainbow trout affected ash and moisture, and inhibited myofibril fragmentation in the fillets. However, with the increase in temperature, there was a decrease in the total amount of saturated fatty acids (∑SFA) and there were significant increases in the total amount of omega 3 (∑n3) and 22:6n-3 (DHA). It was determined that temperature increase had a negative effect on color, texture, water-holding capacity, water activity, pH, lactic acid, and glycogen levels in fillets, and it had a positive effect by delaying microbial spoilage, especially in cold storage. This study suggest that the effects of climate change on product quality and shelf life in fish requires further research. It highlights knowledge gaps to guide future research in this emerging field. © 2023 Society of Chemical Industry.

Ecological and environmental factors affecting the risk of tick-borne encephalitis in Europe, 2017 to 2021.

BackgroundTick-borne encephalitis (TBE) is a disease which can lead to severe neurological symptoms, caused by the TBE virus (TBEV). The natural transmission cycle occurs in foci and involves ticks as vectors and several key hosts that act as reservoirs and amplifiers of the infection spread. Recently, the incidence of TBE in Europe has been rising in both endemic and new regions.AimIn this study we want to provide comprehensive understanding of the main ecological and environmental factors that affect TBE spread across Europe.MethodsWe searched available literature on covariates linked with the circulation of TBEV in Europe. We then assessed the best predictors for TBE incidence in 11 European countries by means of statistical regression, using data on human infections provided by the European Surveillance System (TESSy), averaged between 2017 and 2021.ResultsWe retrieved data from 62 full-text articles and identified 31 different covariates associated with TBE occurrence. Finally, we selected eight variables from the best model, including factors linked to vegetation cover, climate, and the presence of tick hosts.DiscussionThe existing literature is heterogeneous, both in study design and covariate types. Here, we summarised and statistically validated the covariates affecting the variability of TBEV across Europe. The analysis of the factors enhancing disease emergence is a fundamental step towards the identification of potential hotspots of viral circulation. Hence, our results can support modelling efforts to estimate the risk of TBEV infections and help decision-makers implement surveillance and prevention campaigns.

Terrestrial inputs and physical processes control the distributions of potentially toxic elements (PTEs) in the seawater of the large-range Beibu Gulf, the northern South China Sea

The potentially toxic elements (PTEs), Cu, Pb, Zn, Cd, Cr, Hg and As in the water from the Beibu Gulf, were investigated to reveal the contaminant characteristics and assess the risks to human health. The results showed that the concentration of PTEs in the Beibu Gulf varies significantly both seasonally and spatially, with higher concentrations in summer and in the northern and southern gulf. Terrestrial inputs and local anthropogenic discharge are responsible for the higher level in the northern gulf, and the transportation of water masses is also an important factor for the higher concentrations in the southern gulf. Ecological risk assessment suggested that Hg is the main ecological risk factor. The health risk assessment revealed that dermal exposure to PTEs in the gulf presents potentially carcinogenic health effects for humans. This study provides new insight into the transport of PTEs over a large area of the Beibu Gulf.

Behavioural adjustments enable the colonization of subterranean environments

Abstract Specialized subterranean species are iconic examples of convergent evolution driven by environmental constraints, representing an ideal model system for eco-evolutionary studies. However, scientific research on the behavioural adaptations of subterranean organisms has lagged and is biased mostly towards a few model species. Through a systematic literature review, we aimed to assess quantitatively whether a congruent evolution of behavioural traits among subterranean species exists. We considered four types of behaviours (exploratory, feeding, social and anti-predator) and tested predictions about their occurrence among species with different degrees of adaptation to subterranean environments. We argue that these behaviours constitute the earliest adaptations to three main ecological factors characterizing subterranean habitats, namely the constant darkness, the limited food resources and the reduced predator pressure. Darkness selects for individuals that rely on non-visual cues to explore their surroundings, track food resources and locate potential sexual partners. The reduced availability of food promotes high foraging plasticity and deters species from adopting aggressive behaviours towards conspecifics. The reduced predator pressure allows species to abandon specific anti-predator behaviours and permits safer execution of their biological activities. Our analyses show that these four behaviours are likely to represent the result of an early convergent adaptation to the subterranean realm.

Diversity, Ecology and Phytogeography of Bryophytes across Temperate Forest Communities-Insight from Mt. Papuk (Croatia, SE Europe).

It has been widely documented that the complex structure of forest ecosystems supports considerable bryophyte species and functional diversity. In this study, we assessed the diversity, distribution and ecological and phytogeographical features of bryophytes across a gradient of temperate forest types on Mt. Papuk. This is the largest and highest mountain in the lowland, Pannonian part of Croatia, with high geological diversity and various temperate forests covering 95% of the mountain. According to the predominant tree species (oak vs. beech), geological bedrock (calcareous vs. siliceous) and soil reaction (alkaline vs. acidic), 21 study plots were classified into four distinct forest types. In all, 184 bryophyte species (35 liverworts and 149 mosses) were recorded. Although the forest types investigated did not differ significantly with respect to species richness, each was characterized by a considerable number of diagnostic bryophyte species. According to our results, one of the main ecological factors determining the variability of the forest bryophyte composition was geological bedrock and the associated soil reaction. Basiphilous forests developed on carbonate bedrock harbored more thermophilous and nitrophilous bryophytes and were characterized by southern-temperate and Mediterranean-Atlantic biogeographic elements. In contrast, acidophilous forests growing on silicate bedrock were characterized by wide-boreal and boreo-arctic-montane elements, i.e., bryophytes indicating cooler habitats and nitrogen-deficient soils. Based on the results, we hypothesized that the main latitudinal biogeographic distinction between southern and northern biogeographic elements is driven more by geological substrate than by the main tree species in forest communities. The present study confirmed previous findings that bryophytes are good and specific habitat indicators and show associations with different forest types, which can help to understand the complexity, ecological microconditions and biogeographic characteristics of forest communities.

Variations in benthic foraminifera biofacies since Mid-Pleistocene (MIS 7) in the Campos Basin slope, Eastern Brazil: Assessing present-day and past controlling factors

Benthic and planktonic foraminifera faunal and stable isotopic (δ18O and δ13C) analyses on foraminiferal tests were carried out on a piston core, collected from the Campos Basin slope at a water depth of 1475 m. The core location is in front of Cape São Tomé and exhibits landslide scars features. Benthic foraminifera biofacies with ecological indexes and statistics, lithological facies, biostratigraphy and stable isotopic analysis were used to understand the paleoenvironmental evolution of the region by comparison with modern foraminiferal assemblage. Six biofacies were identified between Marine Isotope Stage (MIS) 7 to MIS 1. The main ecological factors controlling the modern assemblages are: bottom currents, slope stability, oxygen concentration, and nutrient input. However, the last two factors are linked to oceanic processes associated with the Paraíba do Sul river, the influence of which has changed in the past. In particular, Biofacies 3, contains infaunal species, points to dysoxic or anoxic periods in the environment, which are interpreted as periods of increased river influence. Changing environmental conditions were observed as the dominant benthic foraminifera species varied down the core, from Epistominella exigua that thrives in stressful conditions, such as sea level oscillations to Globocassidulina crassa, that prefers mild environments during periods of sea level stability.

Ecological and structural differentiation of the Sudanian woodlands in the Biosphere Reserve of Pendjari, Benin

Aims: This study aims to: i) differentiate the plant associations in the Biosphere Reserve of Pendjari (BRP), ii) determine the ecological characteristics of their habitats and iii) present distribution maps on different soil types. Study area: The BRP, located in the Sudanian Zone of Benin. Methods: 202 phytosociological relevés were sampled according to the Braun-Blanquet method within the BRP. Ordination was performed using Detrended Correspondence Analysis to evaluate vegetation patterns. Soil parameters were used to characterize the vegetation types. Results: The numerical analysis of 202 plots and 249 plant species showed two major floristic groups that correlated with a moisture gradient: drylands versus wetlands. The dryland group was a mixture of woodland and shrub savanna, the dominant ecosystems of the study area. The wetland group encompassed species primarily from riparian forest, tree savanna and grass savanna on floodplains. Syntaxonomical analysis of the dryland group showed rocky and gravelly soil associations (Burkeo africanae-Detarietum microcarpi) and soils associated with or without fine gravels (Andropogono gayani-Terminalietum avicennioidis, Andropogono gayani-Senegalietum dudgeonii and Terminalietum leiocarpae). Syntaxonomical analysis of the wetland group showed riparian forest associations on sandy-clay soil (Coletum laurifoliae, Borassetum aethiopi and Hyparrhenio glabriusculae-Mitragynetum inermis) and floodplain associations on silt-clay soil (Terminalio macropterae-Mitragynetum inermis, Brachiario jubatae-Terminalietum macropterae, Sorghastro bipennati-Vachellietum hockii). Conclusions: Eleven new associations were identified in this study. If the distribution of plant associations was determined by different soil properties, the soil humidity would be one of the main ecological factors determining the establishment of plant species and thus plant association development. Taxonomic reference: Akoègninou et al. (2006), Angiosperm Phylogeny Group classification for the orders and families of flowering plants (APG IV, 2016). Abbreviations: BRP = Biosphere Reserve of Pendjari; CBD = Convention on Biological Diversity; CCA = Constrained Correspondence Analysis; DCA = Detrended Correspondence Analysis; GPS UTM = Global Positioning System Universal Transverse Mercator.