Environmental regionalization and endemic plant distribution in the Maghreb

Clustering methods based on environmental variables are useful in the planning of conservation strategies for species and ecosystems. However, there is a lack of work on the regionalization of the vast space of North Africa and the distribution of plant species. The current lists of endemic plants are focused mostly on an occurrence at the country level and not on regions with different conditions. The aim of this work was to lay out an environmental scheme for northwest Africa and to collect data about the occurrence of endemic plants in this area. Clustering with 12 of 33 tested environmental rasters was performed to divide the Maghreb into environmental clusters. Then, a list of 1618 endemic plant taxa (1243 species and 375 subspecies) was prepared and their distribution in estimated environmental clusters was examined. Eleven clusters with different conditions were estimated. The main drivers of regionalization were temperature amplitude, precipitation seasonality, and precipitation of the warmest quarter. According to the occurrence of endemic plants, northwest Africa may be divided into three zones: Atlas, Mediterranean (two environmental clusters), and southern zone (eight environmental clusters). The presented results provide a good basis for understanding the spatial patterns of the Maghreb, including its environment and species diversity. A designed list of endemic plant species together with environmental data may facilitate the planning of future research in north Africa and arranging methods of biodiversity protection.

Heterotrophic Bacteria Play an Important Role in Endemism of Cephalostachyum pingbianense (Hsueh & Y.M. Yang ex Yi et al.) D.Z. Li & H.Q. Yang, 2007, a Full-Year Shooting Woody Bamboo

The previous studies show soil microbes play a key role in the material and nutrient cycles in the forest ecosystem, but little is known about how soil microbes respond to plant distribution, especially in the soil bacterial community in woody bamboo forests. Cephalostachyum pingbianense (Hsueh & Y.M. Yang ex Yi et al.) D.Z. Li & H.Q. Yang, 2007 is known as the only bamboo species producing shoots all year round in natural conditions. Endemic to the Dawei mountain in Yunnan of China, this species is a good case to study how soil bacteria respond to plant endemic distribution. In this work, we assayed the soil chemical properties, enzyme activity, changes in the bacterial community along the distribution range of the C. pingbianense forest. The results showed that soil nutrients at the range edge were nitrogen-rich but phosphorus-deficient, and soil pH value and soil urease activity were significantly lower than that of the central range. No significant difference was detected in soil bacterial diversity, community composition, and function between the central and marginal range of C. pingbianense forest. Notably, the relative abundance of heterotrophy bacteria, such as Variibacter and Acidothermus, in the soil of the C. pingbianense forest was significantly higher than that of the outside range, which may lead to a higher soil organic carbon mineralization rate. These results imply that abundant heterotrophy bacteria were linked to the endemism and full-year shooting in C. pingbianense. Our study is amongst the first cases demonstrating the important role of heterotrophy bacteria in the distribution formation of endemic woody bamboos in special soil habitats, and provides insight into germplasm conservation and forest management in woody bamboos.

Within-Plant Distribution of Two-Spotted Spider Mites, Tetranychus urticae Koch (Acari: Tetranychidae), on Strawberries: Decision of an Optimal Sampling Unit

It is known that two-spotted spider mite (Tetranychus urticae), a major pest of strawberry, is difficult to manage. This study was conducted to determine the optimal sampling unit to increase management efficiency of T. urticae in strawberries. The sampling unit was determined by characterizing within-strawberry distribution of T. urticae and by comparing coefficient of variation (CV) and correlation coefficient (r2) among potential sampling units. There was a significant (p < 0.05) difference in densities within a strawberry according to the leaf age. However, there was no significant difference in its density within a trifoliate leaf. More T. urticae were found on young-fully-opened (moderately old) leaves than on young and old ones. Moreover, these leaves had lower CV and r2 values than others. More specifically, optimal sampling units of T. urticae were fifth, fifth or sixth, and sixth oldest leaves for motiles (immatures and adults), all stages (motiles and eggs), and eggs, respectively. The required sampling number should be determined depending on the density. However, for management purposes, one and two leaflets would be acceptable for eggs and motiles, respectively. By using this small number of suitable sampling unit, the sampling and management for T. urticae in strawberries could be more efficient than before.

The process of discovery in and new species from northern Peru, Cerro Colán, Department Amazonas, Province Bagua

A review of discoveries of plants and animals by a 1978 expedition from Louisiana State University to Peru is presented. Genesis of this study was owing to the senior author’s observation of unusually high species richness in Araceae among a collection of plants made in northern Peru. A subsequent review showed that the region was rich in many ways. Determinations to date include 983 species belonging to 513 genera and 145 families of which 81 species are endemic. Included are 59 plant taxa new to science described elsewhere. Eleven aroids (Araceae) from northern Peru are described and illustrated as new. Some records represent new taxa described from voucher specimens independently collected by botanists at prior or later dates and different localities. A collection was assigned the nov. sp. category of noteworthiness if Tropicos database (http://www.tropicos.org) showed either the Alwyn H. Gentry, et al. and or the Philip J. Barbour accession to be the first such collection known. Specimen searches in Tropicos by senior collector as Philip Barbour and separately by Gentry and constrained by appropriate dates revealed 1687 independent determined voucher specimens of which 1545 are noteworthy (92%) by the designated categories. Noteworthy categories are described and presented in appendices 2 and 3. Extralimital plant distribution records are not described here. Four new bird species/subspecies and seven new frog species were discovered on this expedition. It is important to note that after only 42 years much of the region where many of these discoveries were made is now largely devoid of natural vegetation. Appendix 4 provides detailed descriptions of habitat on Cerro Colán as recent as 2017. This study is a reminder that areas newly opened for exploration should be thoroughly and quickly studied to capture the greatest scientific benefit. It shows how much could be attained in a small span of time by a small but dedicated group of biologists.

Physiological and Proteomic Responses of Contrasting Alfalfa (Medicago sativa L.) Varieties to High Temperature Stress

High temperature (HT) is an important factor for limiting global plant distribution and agricultural production. As the global temperature continues to rise, it is essential to clarify the physiological and molecular mechanisms of alfalfa responding the high temperature, which will contribute to the improvement of heat resistance in leguminous crops. In this study, the physiological and proteomic responses of two alfalfa (Medicago sativa L.) varieties contrasting in heat tolerance, MS30 (heat-tolerant) and MS37 (heat-sensitive), were comparatively analyzed under the treatments of continuously rising temperatures for 42 days. The results showed that under the HT stress, the chlorophyll content and the chlorophyll fluorescence parameter (Fv/Fm) of alfalfa were significant reduced and some key photosynthesis-related proteins showed a down-regulated trend. Moreover, the content of Malondialdehyde (MDA) and the electrolyte leakage (EL) of alfalfa showed an upward trend, which indicates both alfalfa varieties were damaged under HT stress. However, because the antioxidation-reduction and osmotic adjustment ability of MS30 were significantly stronger than MS37, the damage degree of the photosynthetic system and membrane system of MS30 is significantly lower than that of MS37. On this basis, the global proteomics analysis was undertaken by tandem mass tags (TMT) technique, a total of 6,704 proteins were identified and quantified. Gene Ontology (GO) analysis and Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis indicated that a series of key pathways including photosynthesis, metabolism, adjustment and repair were affected by HT stress. Through analyzing Venn diagrams of two alfalfa varieties, 160 and 213 differentially expressed proteins (DEPs) that had dynamic changes under HT stress were identified from MS30 and MS37, respectively. Among these DEPs, we screened out some key DEPs, such as ATP-dependent zinc metalloprotease FTSH protein, vitamin K epoxide reductase family protein, ClpB3, etc., which plays important functions in response to HT stress. In conclusion, the stronger heat-tolerance of MS30 was attributed to its higher adjustment and repair ability, which could cause the metabolic process of MS30 is more conducive to maintaining its survival and growth than MS37, especially at the later period of HT stress. This study provides a useful catalog of the Medicago sativa L. proteomes with the insight into its future genetic improvement of heat-resistance.

Stability Analysis of Ecological Slopes Based on a 3D Finite Element Model

To explore the effect of grass and shrub plant roots on the stability of soil slopes in rainy areas in the south, this article relies on the Longlang Expressway construction project. Cynodon dactylon and Magnolia multiflora were selected as research subjects. The plant distribution characteristics and mechanical properties are analyzed. This paper uses ABAQUS finite element software to construct a 3D model of the planted slope in the test section. The stress and strain on the root system and the soil were observed, and the variation law of slope stability before and after plant protection under different rainfall events was compared and analyzed. The test and simulation results show that the root content of Cynodon dactylon gradually decreases with increasing depth. Cynodon dactylon was mainly distributed in the 0–30 cm soil body, and its effect on improving the cohesion of the soil body reached 75%. Magnolia multiflora belongs to vertical roots and has a strong and longer main root with relatively developed lateral roots. Its root system passes through the sliding surface of the slope bottom, which reduces the maximum equivalent plastic stress generated inside the slope by 61%. When the total rainfall duration is unchanged, under the three rainfall intensities of small, medium, and large, herbaceous plants increase the safety factor of the soil by 1.33%, 2.08%, and 6.1%, respectively, and the roots of shrubs increase the safety factor of the soil by 3.29%, 4.08%, and 4.32%, respectively. When the rainfall intensity does not change, as the rainfall time increases, the effect of plants on the slope safety factor first gradually increases and eventually stabilizes. The research results provide a reliable theoretical basis for analyzing the effect of plant roots on soil consolidation and slope protection, and they also lay a technical foundation for the promotion and application of ecological slope protection technology.

A grid-based database on vascular plant distribution in the Meshchersky National Park, Ryazan Oblast, Russia

Ryazan Oblast, situated in the central part of European Russia, has a long tradition of biodiversity research. Large distributional, ecological and phenological data on various taxonomic groups are available from this territory, mainly in the form of paper publications items, undigitised museum collections and archival sources. The purpose of this dataset is to deliver floristic materials, collected by the authors in the Meshchera Lowlands in the form of GBIF-mediated electronic data, to a wider audience. The dataset covers wild tracheophytes (native species, naturalised aliens and casuals) of the Meshchersky National Park. In 2020, it was used for the production of grid maps in "Flora of the Meschchersky National Park: checklist and atlas". The dataset contains 14,476 grid records of 817 taxa (806 species and hybrids, ten species aggregates and one genus). Most of the records (82.4%) were made in the field by A.V. Shcherbakov, M.V. Kazakova, N.V. Lyubeznova and A.D. Pastushenko in 2017 and 2018. The dataset includes only one occurrence per species per grid square. Georeferences are based on the WGS84 grid scheme with 55 squares measuring ca. 25 km2 (2.5' lat. × 5' long.). Each occurrence is linked to the corresponding grid square centroid; therefore, actual coordinates, habitat details and voucher information are unavailable. As of September 2021, the dataset on the flora of the Meshchersky National Park represents the second largest dataset on the biodiversity of Ryazan Oblast, Russia, published in GBIF.

Seasonal Changes of Some Metabolites in Hyoscyamus boveanus (Dunal) Asch. & Schweinf – Saint Katherine, South Sinai, Egypt

This study was conducted to investigate the effects of seasonal fluctuations on some metabolites and to explore the correlation between soil and plant analysis in Hyoscyamus boveanus (H.boveanus) at the Wadi El-Sheikh Awad in Saint Katherine, South Sinai, Egypt. Significant differences (p < 0.05) were observed for physical and chemical properties of the soil associated with H. boveanus during 0-20 and 20-40 cm depths, which increased most of them during the first depth. All chemical composition contents of H. boveanus are influenced significantly (p < 0.05) by seasons studied, except Na+, glycosides, total phenol, crude protein contents. A substantial increase in mineral composition (Na+, K+, P and Fe2+), total alkaloids, glycosides, total phenol, proline, total carbohydrates and all photosynthetic pigments contents were recorded in H. boveanus during the summer season. While, the mineral composition (Ca2+, Mg2+, S, N and Cl-), water content and crude protein contents appeared to be higher in the winter season. The relationships between soil and plant variables were delineated by performing the principal component analysis (PCA). The PC1 and PC2 displayed differences between the soil and plant variables, also, the variables Mg2+, Cl-, pH, EC, Ca2+ and K+ in the soil associated with H. boveanus are variables with better chemical properties of the soil, which affect the plant distribution in Wadi El-Sheikh Awad during the two seasons. The PCA revealed high positive correlations among soil variables as well as among plant variables. Soil magnesium correlated highly and positively with the plant variables i.e., crude protein, water content, Chl b, Chl a+b, carotein and total pigment contents. The pH, EC, and Ca2+ in soil were positively correlated with all chemical composition contents of H. boveanus. Some metabolites in H. boveanus were significantly increased during the summer season compared to the other season, due to the activation of plant physiological stress tolerance mechanisms.