Semi-desert Plants Research Articles

Продуктивность, кормовое качество и пастбищная емкость зимних пастбищ бассейна реки Сумгаит

The relief, climate and soils of winter pastures located in the Sumgaitchay river basin have been studied. The current state of winter pastures, the type of vegetation, desert and semi-desert plants, associations, formations, forage quality, pasture capacity, and plant productivity have been studied, an action plan has been developed for the protection, improvement and rational use of fodder lands. The productivity of vegetation and phytocenoses of winter pastures, common in the territory of the basin, was determined, and the period of use of winter pastures was determined. In the “State Program” for the reliable provision of the population with food products in the Republic of Azerbaijan for 2008–2015, it is recognized that it is necessary to conduct geobotanical research in pasture areas for the effective use of natural fodder lands, clarifying indicators of their quantity and quality. The research is very relevant.

Bioecological characteristics and importance of feed in xerophyts in the memorial desert plant of the Caspian coast

In order to effectively use the natural ecosystem, the phytocenological structure of the region's vegetation was studied by conducting geobotanical research on the Caspian coast (in the territory of the Republic of Azerbaijan). Taxonomy and ecological-geobotanical map have been compiled. Morphological and ecological features of the species dominating the desert and semi-desert plant groups of the area were studied, as well as their phytocenological classification was developed at the level of type, formation and associations.
 The modern phytocenological classification of the studied vegetation not only protects the biodiversity of the area, but also provides a basis for its efficient use and protection. Taking into account the relief of the area and the diversity of soil and climatic conditions, it was determined by the phytocenological classification of vegetation that phytocenoses belonging to semi-desert, halophytic and psammophytic desert types are widespread in the vegetation of the Caspian coast.
 A new classification of Caspian coastal vegetation has been prepared with reference to our research and studies. According to this guideline and methodology, the classification of desert and semi-desert vegetation is based on eco-phytocenological principles, provided that the life forms of dominant and subdominant species, as well as the systematic taxonomic formations are named according to species and genera, as reflected in the descriptions recorded during field research.
 Thus, based on our geobotanical research and chamber studies, the modern classification of vegetation of the Caspian coast revealed that the plant species belonging to xerophytes in the natural phytocenoses of the area are Chenopodiaceae Vent., Asteraceae Dumort. and Poaceae Barnhart. are represented in the chapter.

Effect of ammonium nitrate on novel cactus pear genotypes aided by biobattery in a semi-arid ecosystem

Plant Microbial Fuel cell (P-MFC) i.e., biobattery is an emerging sustainable technology, which has an obstacle in plant selection with minimal requirement of water resources. Further optimization of the semi-deserting plant under vigorous conditions has a great challenge. In the present study, a P-MFC has been used to evaluate the improvement of power generation in the growth of four cactus pear genotypes aided by ammonium nitrate under semi-arid conditions. Thus, a dosage of 150 mg L¯1 of NH4NO3 per week was applied to the cactus based P-MFCs. Polarization experiments showed that bioelectricity production went from 39 ± 2.74 to 499.2 ± 10.3 mW m¯3 in O. joconostle after treatment. In turn, regarding the long-term operation, O. joconostle showed the highest average power density of 145.39 ± 4.09 mW m¯3. The resultant correlation showed soil electrical conductivity (EC) and cation exchange capacity (CEC) with lower Rint and relative performance. For the plant height parameter, there were significant differences (P-value < 0.05) among the four genotypes evaluated in this study. O. albicarpa indicated the best height of 71.55 ± 0.21 cm. P-MFCs based on semi-desert plants are an economical, viable and sustainable option which could be used in low-income rural areas.

Кербұлақ ауданының табиғи жайылымдарының қазіргі деградация жағдайын бағалау

The article presents materials on the current state of the natural forage lands of the Kerbulak region. Pastures located near the three rural districts Zholaman, Saryozek and Sarybulak were considered as project areas. Using remote sensing (RS) methods, satellite images based on Landsat-8 were processed and a thematic map at a scale of 1: 1,000,000 of soil degradation was compiled, as well as the type of ecological transformation and its degree of impact on agricultural lands leading to disturbance and dehumidification of the land. The article presents data on the dynamics of the annual precipitation and temperature regime of the Kerbulak district of the Almaty region for 2010-2020. Based on these climatic conditions, there was determined nature of their impact on the vegetation cover of pastures. The article identifies desert and semi-desert plant communities that form a natural food base for farm animals. Based on the data provided by the Committee for National Statistics on the number of livestock, the article describes dynamics of the number of livestock over the past 10 years. The article establishes main directions of the development of animal husbandry in this region. Results of the research made it possible to determine the possible causes leading to the processes of desertification and violations of the ecological state in the pastures of the Kerbulak region.

Antifungal activity of phytochemical compounds of extracts from Mexican semi-desert plants against Fusarium oxysporum from tomato by microdilution in plate method

Introduction: In several regions of the world, Fusarium oxysporum causes losses on tomato crops; for control it, chemical fungicides are used. Nevertheless, these fungicides causing environmental and resistance problems; therefore, ecological alternatives as plant extracts have been developed. Due to the aim of this work, identify phytochemicals present in ethanolic and aqueous extracts from Agave lechuguilla qualitatively, Carya illinoinensis, Jatropha dioica, Larrea tridentata, and Lippia graveolens and determine their antifungal activity against F. oxysporum.Method: The plants collected from the northeast of Mexico; crudes and concentrated plant extracts obtained; the inhibition percentage and inhibitory concentration to 50 % (IC50) of F. oxysporum for each plant extract were determinate trough microdilution in the plate methodResults: The essential phytochemicals were flavonoids, saponins, tannins, and quinones. The antifungal activity showed at 1000 mg/L inhibition around 40 to 60% by aqueous crude extracts from leaves of L. graveolens and concentrated aqueous extracts from the stem of L. graveolens, respectively. The ethanolic extracts presented 100 % of inhibition for crude extracts of husk from C. illinoinensis; in leaves and stem from L. graveolens the inhibition started from 250 mg/L; for resuspended extracts, the inhibition started from 125 mg/L with L. graveolens stem and leaves; and finally in roots of A. lechuguilla and leaves from L. graveolens the inhibition started from to 250 and 500 mg/L respectively. The best IC50 was of 8.02 mg/L from the ethanolic resuspended extract of L. graveolens stem.Conclusion: The ethanolic plant extracts from L. graveolens, A. lechuguilla, and C. illinoinensis, showed 100 % of inhibiting activity against the development of F. oxysporum, representing an alternative for control of F. oxysporum.

The 'fertile island effect' of Welwitschia plants on soil microbiota is influenced by plant gender.

Desert and semi-desert plants are often associated with a distinct soil biota under the plants and close to the root system. We aimed to understand if similar effects could be found in the taxonomically isolated desert gymnosperm Welwitschia mirabilis in the Namib Desert, and whether this island effect varied with climate and with gender of plants. We took soil cores adjacent to the plants in environments ranging from extreme desert to arid shrubland, and in nearby control sites between the plants. Soil chemistry was analysed, and deoxyribonucleic acid was extracted and sequenced for the bacterial 16s region. Soil under the plants was richer in organic C, N and moisture. Despite the range of climates, the soil around Welwitschia plants was consistently associated with a particular bacterial community composition that was distinct from samples further away. Compared to unvegetated control patches, bacterial diversity close to the plants was reduced. In the plant-associated soil community, there was a clear gender effect across all sites with a distinct community composition and greater diversity under male plants. It is unclear what differences in the soil environment might be producing these gender-associated differences, which provide an additional dimension to the fertile island effect.

Phylogeny and biogeography of the Pleistocene Holarctic steppe and semi-desert goosefoot plant Krascheninnikovia ceratoides

Krascheninnikovia ceratoides (Chenopodiaceae) is a steppe and semi-desert plant with two subspecies, K. ceratoides subsp. ceratoides, which is widespread in Eurasia, and K. ceratoides subsp. lanata, which grows in western and central North America. A few disjunct populations of K. ceratoides subsp. ceratoides are found in Anatolia, Europe and North Africa to the west of its otherwise continuous Eurasian distribution. To understand the evolutionary history of this characteristic steppe and semi-desert plant, we analysed its phylogeny and biogeography. We sequenced several loci including ITS, ETS and the chloroplast intergenic spacer regions atpB-rbcL, rpl32-trnL and trnL-trnF to establish a time-calibrated phylogeny and reconstruct intraspecific relationships. Furthermore, we identified the ploidy level of individuals. While diploid, tetraploid and hexaploid individuals have been reported in the literature, we were only able to find diploids and tetraploids. The diploids were found in the east of Mongolia, Kazakhstan, Kyrgyzstan, Russia and the USA. The tetraploids were located in the west of Mongolia, Kazakhstan, Tajikistan, Russia, and Europe. Populations were uniformly di- or tetraploid. Our results indicate that the species may have spread from the area of Mongolia, northern China and Middle Asia (i.e., the Altai Mountains region) in two opposite directions – on the one hand, diploids migrated to the east, to eastern Asia and North America, and on the other hand diploids and tetraploids migrated to the west, to western Asia and Europe. Fossil-calibrated gene trees were used to estimate the age of the species. Diversification within the species is probably of Pleistocene age. Our dated analysis indicates that the first split among extant lineages of the species took place in the Early Pleistocene (Gelasian). The spread of the main lineages is likely related to major phases of steppe and semi-desert expansions during glacial periods of the Pleistocene.

Habitat, occurrence and conservation status of the Saharo-Macaronesian and Southern-Mediterranean element Fagonia cretica L. (Zygophyllaceae) in Italy

Fagonia cretica L. is an important component of Mediterranean dry grasslands and a rare and isolated species of Italian flora. In this study, an assessment is presented on the distribution, habitat, and conservation status of F. cretica in Italy. The results of field investigation and herbarium analysis show that this species grows in a small area within the southern Calabria region characterized by a warmest and driest Mediterranean climate on the Italian peninsula. F. cretica is a semi-desert plant species growing in Italy in only one peripheral and isolated population at the northern limit of its distribution. Plant community analysis, using the phytosociological method, shows that F. cretica grows in wintergreen perennial dry grasslands dominated by Lygeum spartum and Hyparrhenia hirta. F. cretica plant communities are located in thermo-xeric habits such as south-, southeast- and east-facing slopes on clays and sandy clays in southern Calabria. The population of F. cretica is fragmented in six neighbouring localities, with two of which belonging to a Site of Community Importance (SCI). The conservation status of F. cretica population is not very good, and is defined as “Critically Endangered” in accordance with IUCN criteria. There are many threats affecting the F. cretica population in Italy, primarily the changes in land uses due to urban expansion and reforestation with exotic plants. The southern end of the Italian peninsula hosts other plants from thermo-xeric habits that do not adapt to the current local climate. This territory can be considered as a microrefugia for plants currently distributed in the arid territory of the southern Mediterranean. These results contribute to the discussion of some conservation measures, and the possibility of establishing a micro-reserve. For all these reasons, we propose to include F. cretica in the lists of protected plant species at regional (Calabria) and country (Italy) scales in Italy.

BIOMORPHOLOGICAL STRUCTURE OF THE FLORA OF COASTAL ECOSYSTEMS OF DAGESTAN

Aim . Analysis of the over all spectrum of life forms of the flora of coastal ecosystems of Dagestan and structural variability of the spectrum indifferent types of plant communities. Methods . The species composition of plant communities and their structural and dynamic features have been determined according to biomorphological indicators during the research and post-processing of the collected material. Based on system of Raunkiera K. (1934) there have been identified five major biomes (fanerofity, hamefity, hemicryptophytes, cryptophytes, terofity) of the flora of coastal ecosystem sof Dagestan, without any further specification. Results . Hemicryptophytes numbering 437 species or 43.52% of the total species composition have been dominated in the flora of coastal ecosystems of Dagestan. In second place terofity (388 species, or 38.64%), the third cryptophytes (80 species or 7.97%). Fanerofity and hanefite are respectively 6.57% and 3.68%. Thus, herbaceous species account or 905 species, or 90.13%. Trees, bushes and shrubsaccountfor a totalof 103 species, or 9.87%. A fairly large percentage of Trofimov can be explained by participation in the studied flora of weedy annuals. Main conclusions. By dominant, similar to the total spectrum of life forms of flora, the position of hemicryptophytes and Trofimov semi-desert and dry steppe plant communities are zonal and climatically determined for this area.

Miocene–Pliocene vegetation change in south-western Africa (ODP Site 1081, offshore Namibia)

Abstract Aridification is an important component of Late Neogene climate change in south-western Africa probably caused by modifications in the atmospheric circulation in relation to the initiation and intensification of the Benguela Upwelling System due to globally steepening of the meridional pressure gradient. Intensification of the meridional pressure gradient influenced the climate intensively which had then an impact on the vegetation. However, vegetation changes of south-western Africa from the Miocene to Pliocene have not yet been reported and only indirectly investigated by sedimentological data. Here, we present a pollen record of marine ODP Site 1081 retrieved 160 km offshore Namibia covering the time between 9 and 2.7 Ma. Using an endmember unmixing model we distinguished three vegetation phases as follows: a relative wet phase, during the Tortonian, showing higher representations of Cyperaceae, a transition phase during the Messinian, when especially grasses expanded, and a dry one covering the Pliocene with a strong representation of desert and semi-desert plants. The three phases indicate ongoing aridification probably caused by intensified meridional pressure gradients. Additionally, aquatic vegetation indicators appear in our pollen record from around 5 Ma on, which we attribute to a relocation of the lower course of the Cunene River to its modern outlet in the Atlantic Ocean. Redirection of the Cunene River toward the Atlantic would have deprived the palaeolake Cunene of an important source of fresh-water ultimately resulting in desiccation of the lake and the formation of the Etosha Pan.

English

Plant extracts are an important part in agroecology, as they benefit environment in combating pathogenic organisms, without resorting to synthetic chemicals. The objective of this study was to evaluate the antibacterial activity of mixtures of ethanol extracts from semi-desert plants [creosote bush ( Larrea tridentata ), tarbush ( Flourensia cernua ) and paddle cactus ( Opuntia ficus-indica )] against Enterobacter aerogenes, Escherichia coli, Salmonella typhi and Staphylococcus aureus . The maximum antimicrobial activity was achieved with the creosote bush–tarbush-paddle cactus mix (1:1:1) v/v, followed by paddle cactus-tarbush (1:1) v/v. E. coli was the bacterial strain that showed the highest growth inhibition as consequence of the concentration of plant extracts (4000 and 5000 ppm of tarbush). While with the creosote bush plant extracts, the highest inhibition halos were observed. Synergistic effects were observed when mixtures of ethanolic plant extract against food-borne pathogen bacteria were used, so this may be a better way to design alternative pathogen control methodologies for food-borne pathogen bacteria. Keywords: Larrea tridentate, Flourensia cernua, Opuntia ficus-indica , ethanolic plant extract mixtures, foodborne pathogen African Journal of Biotechnology , Vol. 13(5), pp. 699-704, 29 January, 2014

Antidiabetic Attributes of Desert and Steppic Plants: A Review

The rapidly increasing incidence of diabetes mellitus is becoming a serious threat to mankind's health in all parts of the world. In fact, known cases reflect only part of the problem, as many diabetics, especially with type 2 diabetes, are unaware of their disease, which initially shows no definitive symptoms. Despite the great efforts invested in diabetes research, its prevalence continues to grow, while current medications do not cover all of the symptoms and complications of the disease. The present review highlights a plethora of studies focusing on the antidiabetic properties of desert and semidesert (steppic) plants, many of them being used for centuries in traditional medicine by Bedouins living in the arid zones of the Middle East and also by ethnic groups in other arid and semiarid parts of the world. The review concludes in summarizing the work done on the subject and also in pointing to the yet existing gaps in diabetes research of desert and steppic plants, and suggests directions for future exploration.

Deglacial and Holocene vegetation and climatic changes in the southern Central Mediterranean from a direct land–sea correlation

Abstract. Despite a large number of studies, the long-term and millennial to centennial-scale climatic variability in the Mediterranean region during the last deglaciation and the Holocene is still debated, including in the southern Central Mediterranean. In this paper, we present a new marine pollen sequence (core MD04-2797CQ) from the Siculo-Tunisian Strait documenting the regional vegetation and climatic changes in the southern Central Mediterranean during the last deglaciation and the Holocene. The MD04-2797CQ marine pollen sequence shows that semi-desert plants dominated the vegetal cover in the southern Central Mediterranean between 18.2 and 12.3 ka cal BP, indicating prevailing dry conditions during the deglaciation, even during the Greenland Interstadial (GI)-1. Across the transition Greenland Stadial (GS)-1 – Holocene, Asteraceae-Poaceae steppe became dominant till 10.1 ka cal BP. This record underlines with no chronological ambiguity that even though temperatures increased, deficiency in moisture availability persisted into the early Holocene. Temperate trees and shrubs with heath underbrush or maquis expanded between 10.1 and 6.6 ka, corresponding to Sapropel 1 (S1) interval, while Mediterranean plants only developed from 6.6 ka onwards. These changes in vegetal cover show that the regional climate in southern Central Mediterranean was wetter during S1 and became drier during the mid- to late Holocene. Wetter conditions during S1 were likely due to increased winter precipitation while summers remained dry. We suggest, in agreement with published modeling experiments, that the early Holocene increased melting of the Laurentide Ice Sheet in conjunction with weak winter insolation played a major role in the development of winter precipitation maxima in the Mediterranean region in controlling the strength and position of the North Atlantic storm track. Finally, our data provide evidence for centennial-scale vegetation and climatic changes in the southern Central Mediterranean. During the wet early Holocene, alkenone-derived cooling episodes are synchronous with herbaceous composition changes that indicate muted changes in precipitation. In contrast, enhanced aridity episodes, as detected by strong reduction in trees and shrubs, are recorded during the mid- to late Holocene. We show that the impact of the Holocene cooling events on the Mediterranean hydroclimate depend on baseline climate states, i.e. insolation and ice sheet extent, shaping the response of the mid-latitude atmospheric circulation.

Degradation of the vegetation cover as exemplified by the arid foothill areas of the greater caucasus within Azerbaijan

Field observations were used in compiling the map for contemporary vegetation of the Acinour-Ceyrancol foothill areas having regard to the altered floristic composition of steppe and semidesert plant communities. The study revealed a decrease in the area occupied by juniper sparse forests and riparian forests. It is found that a severe anthropogenic influence in this area leads to desertification and degradation of landscapes.

Antibacterial activity of plant extracts obtained with alternative organics solvents against food-borne pathogen bacteria

The objectives of this study were: the chemical characterization of extracts from seven plants (Larrea tridentata, Flourensia cernua, Lippia graveolens, Agave lechuguilla, Yucca filifera, Opuntia ficus-indica, and Carya illinoensis) which are acclimated to the Mexican semi-desert. The extracts were obtained using Soxhlet method by water, ethanol and an infusion method using alternative organic solvents (lanolin and cocoa butter), in addition it was evaluated the antibacterial activity of semi-desert plant extracts against Enterobacter aerogenes, Escherichia coli, Salmonella typhi and Staphylococcus aureus. Chemical characterization of plant extracts showed that they are rich in secondary metabolites; cocoa butter was the non-conventional solvent which it was possible to obtain the highest content of total tannins. It was not possible to identify saponins in those extracts where non conventional solvents were used. While in extract where non conventional solvents were used, it was only possible to detect the presence of terpenes in creosote bush and prickly pear extracts. S. aureus was the bacterial strain that showed the highest growth inhibition as consequence of the plant extracts. The use of semi-desert plant extracts obtained using organic solvents are a good alternative for food-borne pathogen bacteria control because all the bacterial growth decreased with the tested extracts.

Palyonological studies of the semi-desert plant species from Pakistan

The detailed palynological description of 40 angiospermic plant species, belonging to 22 families and 38 genera were made. Out of the 22 families, 3 families were monocotyledonous and 19 dicotyledonous. The Brassicaceae and Papilionaceae were the largest families regarding number of species having four species each. In all the species except Poaceae, the pollen types were tricolporate. In case of Calendula arvensis L., Salvia aegyptica, Melia azedarrach tetracolporate pollens were observed, in Carum copticum (L.) Bth, the pollens were bicolpate; in Cynoglosum lanceolatum Forssk., it was fenestrate while in Bougainvillea glabra Choisy., it was periporate. Thus, the present study was fruitful as it avoids the difficulties faced by taxonomists and plant scientists in correlating and differentiating plant species.

Mineral nutrient uptake from prey and glandular phosphatase activity as a dual test of carnivory in semi-desert plants with glandular leaves suspected of carnivory.

Ibicella lutea and Proboscidea parviflora are two American semi-desert species of glandular sticky plants that are suspected of carnivory as they can catch small insects. The same characteristics might also hold for two semi-desert plants with glandular sticky leaves from Israel, namely Cleome droserifolia and Hyoscyamus desertorum. The presence of proteases on foliar hairs, either secreted by the plant or commensals, detected using a simple test, has long been considered proof of carnivory. However, this test does not prove whether nutrients are really absorbed from insects by the plant. To determine the extent to which these four species are potentially carnivorous, hair secretion of phosphatases and uptake of N, P, K and Mg from fruit flies as model prey were studied in these species and in Roridula gorgonias and Drosophyllum lusitanicum for comparison. All species examined possess morphological and anatomical adaptations (hairs or emergences secreting sticky substances) to catch and kill small insects. The presence of phosphatases on foliar hairs was tested using the enzyme-labelled fluorescence method. Dead fruit flies were applied to glandular sticky leaves of experimental plants and, after 10-15 d, mineral nutrient content in their spent carcasses was compared with initial values in intact flies after mineralization. Phosphatase activity was totally absent on Hyoscyamus foliar hairs, a certain level of activity was usually found in Ibicella, Proboscidea and Cleome, and a strong response was found in Drosophyllum. Roridula exhibited only epidermal activity. However, only Roridula and Drosophyllum took up nutrients (N, P, K and Mg) from applied fruit flies. Digestion of prey and absorption of their nutrients are the major features of carnivory in plants. Accordingly, Roridula and Drosophyllum appeared to be fully carnivorous; by contrast, all other species examined are non-carnivorous as they did not meet the above criteria.

Vegetation Responses following Wildfire on Grazed and Ungrazed Sagebrush Semi-Desert

A 20-year set of cover data on sagebrush semi-desert plant communities responding to wildfire and livestock grazing near Mills in central Utah provided an opportunity to compare the assumptions and adaptability of classical and state-and-transition models for describing secondary succession. Cover data were organized and analyzed by plant species, growth forms, and other ground cover classes. Graphical analysis, ordination (employing semi-strong hybrid multi-dimensional scaling), regression, and analysis-of-variance were used to determine whether the patterns observed were best described as community change (tightly linked species) or individualistic change (each species acting independently). Distinct differences in total plant cover, growth form, and species composition were found between burned (both grazed and ungrazed) and the unburned and grazed treatments. Conventional graphical and statistical analyses of burned and ungrazed plots showed greater and earlier expansion of perennial grasses and then relatively less cover-weighted compositional change in recent years compared to the other treatments. Vegetation on none of the treatments appears to have stabilized toward either the pre-burn sagebrush semi-desert, a new state or the potential natural community for the site involved. Pathways of change reflected in the ordinations have been complex in all treatments. The only obvious trends in responses of individual species were to fire and the inverse relationship of cheatgrass to total perennial vegetational cover. All this evidence points to few tight linkages between species or growth form groups and thus favors viewing these patterns individualistically. While the state-and-transition model allows greater flexibility than the classical model in the depiction of plant community/individual species changes consequent to any management action, it doesn't apply readily everywhere, as exemplified by this case study. DOI:10.2458/azu_jrm_v55i2_west

Vegetation responses following wildfire on grazed and ungrazed sagebrush semi-desert

A 20-year set of cover data on sagebrush semi-desert plant communities responding to wildfire and livestock grazing near Mills in central Utah provided an opportunity to compare the assumptions and adaptability of classical and state-and-transition models for describing secondary succession. Cover data were organized and analyzed by plant species, growth forms, and other ground cover classes. Graphical analysis, ordination (employing semi-strong hybrid multi-dimensional scaling), regression, and analysis-of-variance were used to determine whether the patterns observed were best described as community change (tightly linked species) or individualistic change (each species acting independently). Distinct differences in total plant cover, growth form, and species composition were found between burned (both grazed and ungrazed) and the unburned and grazed treatments. Conventional graphical and statistical analyses of burned and ungrazed plots showed greater and earlier expansion of perennial grasses and then relatively less cover-weighted compositional change in recent years compared to the other treatments. Vegetation on none of the treatments appears to have stabilized toward either the pre-burn sagebrush semi-desert, a new state or the potential natural community for the site involved. Pathways of change reflected in the ordinations have been complex in all treatments. The only obvious trends in responses of individual species were to fire and the inverse relationship of cheatgrass to total perennial vegetational cover. All this evidence points to few tight linkages between species or growth form groups and thus favors viewing these patterns individualistically. While the state-and-transition model allows greater flexibility than the classical model in the depiction of plant community/individual species changes consequent to any management action, it doesn't apply readily everywhere, as exemplified by this case study.

Eastern Mediterranean Quaternary paleoclimates from pollen and isotope records of marine cores in the Nile Cone Area

Pollen spectra from three eastern Mediterranean cores have been used to document the paleoclimates of the Levantine Basin borderlands over the last 250 kyr to establish the relationship between this regional climate data set and the global climate as recorded by foraminiferal δ18O and to compare it with proximal land pollen records. Core MD 84 642 with eight sapropels covers the last two climatic cycles up to the early Holocene, MD 84 627 with four sapropels goes back to 125 kyr, and MD 84 629 with one sapropel covers the last 70 kyr. The sedimentation rate decreases from core 629, located at the shallowest depth beneath the Nile River plume, to cores 627 and 642. During the interglacials defined by a low 18O/16O ratio, the abundance of tree pollen is maximum and points to an optimum Mediterranean climate with greatest humidity, including some summer rainfall. During glacial maxima, with highest 18O/16O ratio, the pollen abundance is high for steppe and semidesert plants and low for trees, indicating a definitely more arid, more continental, and probably colder climate. The variations of pollen abundance occur in phase with those of the foraminifer δ18O record. This signifies that the regional climate of the Levantine Basin borderlands had the same temporal pattern as the global ice volume documented by the ice volume curve.