The relationship between structure and ecosystem services of forest and grassland based on pattern analysis method: A case study of the Mongolian Plateau.

Global warming has led to severe land desertification on the Mongolian plateau. It puts great environmental pressure on vegetation communities. This pressure leads to fragmentation of land use and landscape patterns, thus triggering changes in the spatial distribution patterns of vegetation. The spatial distribution pattern of vegetation is crucial for the performance of its ecosystem services. However, there is not enough research on the relationship between large-scale spatial distribution patterns of vegetation and ecosystem services. Therefore, this study is to construct an ecological spatial network on the Mongolian Plateau based on landscape ecology and complex network theory. Combining pattern analysis methods to analyze the network, we obtained the spatial and temporal trends of forest and grass spatial distribution patterns from 2000 to 2100, and explored the relationship between the topological properties of source patches and ecosystem services in different patterns. It was found that there are four basic patterns of spatial distribution of forest and grass in the Mongolian Plateau. The Core-Linked Ring pattern accounts for 40.74 % and exhibits the highest stability. Under the SSP5-RCP8.5 scenario, source patches are reduced by 22.76 % in 2100. Topological indicators of source patches showed significant correlations with ecosystem services. For example, the CUE of grassland patches in the Centralized Star pattern was positively correlated with betweeness centrality. The most significant improvement in WUE after optimization is 19.90 % compared to pre-optimization. The conclusion of the study shows that the spatial distribution pattern of vegetation can be used to enhance the stability of ecological spatial network and improve ecosystem services at a larger scale. It can provide a certain reference for the study of spatial patterns of vegetation distribution in arid and semi-arid areas.

Impact of Climate Change on Management of Systemic Hypertension in North-Eastern Nigeria.

The impact of climate change on health, including changes in epidemiology and heat-related complications, has been variously reported in many parts of the world. Maiduguri, the capital of Borno state in north-eastern Nigeria, has been bearing the brunt of increasing temperatures over the past years, especially during the early months of the year building up to the commencement of the rainy season; with an average daily temperature forecasted to be around 40C. Patients with systemic hypertension and other forms of cardiovascular diseases are vulnerable to heat-related complications including dehydration, hypotension, and orthostatic hypotension (OH). This is particularly true in patients receiving various forms of antihypertensive medication, including diuretics. We present three cases of symptomatic OH occurring during the peak of heat season in Maiduguri among patients receiving various combinations of antihypertensive medication.L'impact du changement climatique sur la santé, y compris les changements dans l'épidémiologie et les complications liées à la chaleur, a été diversement rapporté dans de nombreuses régions du monde. Maiduguri, la capitale de l'État de Borno, dans le nord-est du Nigeria, a subi de plein fouet l'augmentation des températures au cours des dernières années, en particulier au cours des premiers mois de l'année, jusqu'au début de la saison des pluies. Les patients souffrant d'hypertension systémique et d'autres formes de maladies cardiovasculaires sont vulnérables aux complications liées à la chaleur, notamment la déshydratation, l'hypotension et l'hypotension orthostatique (OH). Cela est particulièrement vrai chez les patients recevant diverses formes de médicaments antihypertenseurs, notamment des diurétiques. Nous présentons trois cas d'OH symptomatique survenus pendant le pic de la saison chaude à Maiduguri chez des patients recevant diverses combinaisons de médicaments antihypertenseurs. Mots clés: Changement climatique, Hypertension, Agents antihypertenseurs, Hypotension orthostatique, Zone semiaride, Maiduguri, Nigeria.

Latitudinal variation in the woody species diversity and population structure of Lannea microcarpa Engl. and K. Krause in Burkina Faso.

Latitude is source of variations of plant species diversity and stand structure. This study aimed to characterize the populations of the African grape tree, Lannea microcarpa, in its range in Burkina Faso. Data were collected according to oriented sampling scheme, based on the presence of the species. Overall, 140 inventory plots of 1000 m2 each were considered across the sub-Sahelian, north-Sudanian and south-Sudanian phytogeographical zones. Tree diameter at breast height (DBH) and total height of L. microcarpa individuals were measured and all woody species in each plot were recorded. A comparative analysis was made between zones for woody flora diversity associated with L. microcarpa, dendrometric and stand structure parameters. The results revealed a total woody flora richness of 109 species. Correlogram analysis revealed that species associated with L. microcarpa differed between phytogeographical zones. Ten species showed a probability of association with L. microcarpa. The density of L. microcarpa populations and the floristic diversity of its habitats decreased significantly (p < 0.001) from sub-Sahelian to south-Sudanian zones. The diameter classes' structure in the three phytogeographical zones revealed unstable populations with a predominance of intermediate classes compared to extreme classes. The height structure of juveniles is marked by a poor transition between the different classes, showing unpredictable regeneration of L. microcarpa in the three phytogeographical zones. The results of this study draw attention to the need to adopt conservation measures for the species. In this sense, the data on the comparative demographic characteristics can serve as a basis for the implementing of adequate management strategies of natural populations of the species across its distribution range in Burkina Faso.

Climatic Zone and Soil Properties Determine the Biodiversity of the Soil Bacterial Communities Associated to Native Plants from Desert Areas of North-Central Algeria.

Algeria is the largest country in Africa characterized by semi-arid and arid sites, located in the North, and hypersaline zones in the center and South of the country. Several autochthonous plants are well known as medicinal plants, having in common tolerance to aridity, drought and salinity. In their natural environment, they live with a great amount of microbial species that altogether are indicated as plant microbiota, while the plants are now viewed as a "holobiont". In this work, the microbiota of the soil associated to the roots of fourteen economically relevant autochthonous plants from Algeria have been characterized by an innovative metagenomic approach with a dual purpose: (i) to deepen the knowledge of the arid and semi-arid environment and (ii) to characterize the composition of bacterial communities associated with indigenous plants with a strong economic/commercial interest, in order to make possible the improvement of their cultivation. The results presented in this work highlighted specific signatures which are mainly determined by climatic zone and soil properties more than by the plant species.

Characterization, activities, and ethnobotanical uses of Mentha species in Morocco.

This work is a summary of the characterization, activities, and ethnobotanical surveys about aromatic and medicinal plants belonging to the genus Mentha in Morocco. The Mentha species investigated are Mentha pulegium, Mentha spicata, Mentha viridis, Mentha suaveolens, Mentha longifolia, Mentha gattefossei, Mentha rotundifolia, and Mentha vulgare, with M. pulegium being the most studied species. M. spicata and M. viridis are poorly explored even though they are daily consumed by Moroccans in tea infusions. The elucidated factors affecting the composition of Mentha essential oils are fertilization, drying conditions, mechanical impedance, NaCl stress, and Gamma irradiation. Investigation of the activities of the Mentha species showed that the main interest was dedicated to addressing the antibacterial effect towards gram+ and gram- bacteria. Essential oils of Mentha species exhibited antifungal, antiviral, antioxidant, insecticidal, licidal, niticidal, allelopathic, antidiabetic, derma-protective, and anticorrosive activities. The ethnobotanical surveys revealed that Mentha species are used in seven regions: Tafilalet, High Atlas, Fez-Boulemane, Taounat, Oujda, Ouazzane, and Rabat. By calculating the Jaccard index, the highest degree of similarity was found between Tafilalet, Rabat, and Oujda regions. The wide use of the Mentha species in Morocco highlights the high ethnobotanical value of the genus.

Differences in structure of northern Australian hypolithic communities according to location, rock type, and gross morphology.

Hypolithic communities (under translucent rocks) were compared between a semi-arid site (Wave Hill) and a site with considerably higher rainfall (Lake Bennett) to test the hypothesis that the communities at the higher rainfall site would be more diverse. A total of 153 cyanobacteria operational taxonomic units (OTUs) were identified, and only 50 of those were found at both sites. Of these, only two were core OTUs, as defined as being present in ≥90% of samples, highlighting the extreme differences in the cyanobacterial communities at the two sites. At Wave Hill, we compared the composition of the cyanobacterial components under two different rock types (quartz and prehnite) to determine if the different minerals would result in different hypolithic communities, but no differences were found. Of the 42 core OTUs found at Wave Hill, 22 (52%) were shared between the two rock types. As hypothesised, the diversity of both cyanobacteria and eukaryotes in the hypolithic communities was significantly higher at Lake Bennett. Some hypolithic communities were thin and tightly adhered to the rock surface, but others were thicker and could be peeled off the rock in sheets. However, the two types were not significantly different in OTU composition. Metazoans, primarily nematodes, were ubiquitous, raising the possibility that nematodes may act as vectors to transport the components of hypolithic communities from rock to rock as a mechanism of colonization.

Quality of urban runoff in wet and dry seasons: a case study in a semi-arid zone.

Urban runoff (UR) is a promising new resource that may alleviate growing tensions in numerous arid and semi-arid regions of the world. However, it is precisely in these zones that the available UR quality characteristics are scarcer. This work aims to evaluate a wide set of parameters to establish a detailed approach to both the quality of UR in a midsized city in Central Mexico and the feasibility of using UR to recharge aquifers. UR from an institutional land use site was sampled during wet and dry seasons and assessed for suspended solids, organic matter, nutrients, microorganisms, metals, and persistent organic chemicals (i.e., polycyclic aromatic hydrocarbons, PAH). The results were analyzed using multivariate statistical methods to identify relationships among the variables, the sampling sites and the seasons. The soil erosion and the leaching of materials due to the water flow through vegetated areas were identified as the most influencing factor on the quality of the site runoff in both dry and wet seasons. Additionally, data were more heterogeneous during the dry season, and higher pollutant concentrations were found both during the dry season and in more pervious zones. We consider UR a promising water source for recharging aquifers in arid and semi-arid zones if a program is implemented that can integrate an adequate runoff treatment system, soil protection, and other non-structural measures.

The critical role of ants in the extensive dispersal of Acacia seeds revealed by genetic parentage assignment.

Ants are prominent seed dispersal agents in many ecosystems, and dispersal distances are small in comparison with vertebrate dispersal agents. However, the distance and distribution of ant-mediated dispersal in arid/semi-arid environments remains poorly explored. We used microsatellite markers and parentage assignment to quantify the distance and distribution of dispersed seeds of Acacia karina, retrieved from the middens of Iridomyrmex agilis and Melophorus turneri perthensis. From parentage assignment, we could not distinguish the maternal from each parent pair assigned to each seed, so we applied two approaches to estimate dispersal distances, one conservative (CONS), where the parent closest to the ant midden was considered to be maternal, and the second where both parents were deemed equally likely (EL) to be maternal, and used both distances. Parentage was assigned to 124 seeds from eight middens. Maximum seed dispersal distances detected were 417 m (CONS) and 423 m (EL), more than double the estimated global maximum. Mean seed dispersal distances of 40 m (±5.8 SE) (CONS) and 79 m (±6.4 SE) (EL) exceeded the published global average of 2.24 m (±7.19 SD) by at least one order of magnitude. For both approaches and both ant species, seed dispersal was predominantly (44-84% of all seeds) within 50 m from the maternal source, with fewer dispersal events at longer distances. Ants in this semi-arid environment have demonstrated a greater capacity to disperse seeds than estimated elsewhere, which highlights their important role in this system, and suggests significant novel ecological and evolutionary consequences for myrmecochorous species in arid/semi-arid Australia.

Demographic study of two population outbreaks of Elasmoderus wagenknechti (Liebermann) (Orthoptera: Tristiridae) in the transitional desert of Chile

Under certain environmental conditions, several species of grasshoppers inhabiting rangeland areas (e.g., inter-valleys) of the Chilean transitional desert can irrupt demographically. One of them is Elasmoderus wagenknechti (Liebermann), an endemic species. We studied two outbreaks occurred in 1996 and 1999. The objectives of the research were to (i) estimate some demographic parameters associated with the aforementioned events, and (ii) compare between them the population parameters. The parameters we studied were density (ind/m²), sexual proportion, female fertility (i.e., eggs/female), and the relationship eggs/female versus female size. Density (ind/m²) ranged from 0.2 to 0.4 in 1996 and from 0.5 to 0.6 in 1999. ANOVA-tests registered differences in density among study sites and between years. In some of the study sites, females were more abundant than males (e.g., Lomas del Sauce). Females fertility ranged from 27 to 39 eggs per female, with significant differences among sites in 1996 but not in 1999. For females of 30-50 mm body size, a linear relationship was detected between egg number/female and body size. It is concluded that the E. wagenknechti outbreaks are site-specific in the study area and that the demographic parameters examined show a high variability among sites and between events.

Sob certas condições ambientais, diversas espécies de gafanhotos que habitam áreas de campos, como as áreas entre vales do deserto transicional do Chile, podem experimentar surtos populacionais. Uma dessas espécies é Elasmoderus wagenknechti (Liebermann), espécie endêmica. Nós estudamos dois surtos que ocorreram em 1996 e 1999. Os objetivos da pesquisa foram (1) estimar alguns parâmetros demográficos associados aos eventos acima indicados, e (2) comparar os parâmetros entre os eventos. Os parâmetros estudados foram densidade (indivíduos/m²), razão sexual, fertilidade da fêmea (i.e., ovos/fêmea), e a relação entre a fertilidade e o tamanho corporal da fêmea. O intervalo da densidade do evento foi estimado entre 0,2 e 0,4 indivíduos/m² em 1996, e entre 0,5 e 0,6 indivíduos /m² em 1999. Foram encontradas diferenças (análise de variância) na densidade entre os locais para o mesmo evento, e entre os eventos. As fêmeas foram mais numerosas que os machos em alguns locais estudados (e.g., Lomas del Sauce). Foi estimado um intervalo médio de 27-39 ovos/fêmea, existindo diferenças entre os locais no evento de 1996, mas não no evento de 1999. Para fêmeas de longitude corporal de 30-35 mm. foi detectada uma relação linear entre número de ovos/fêmea e tamanho corporal. Em conclusão, a magnitude do evento na área de estudo é específica do local; além do que para os parâmetros demográficos examinados existe uma acentuada variabilidade entre locais e entre os eventos.