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Rocky Outcrops (rocky + outcrop)
Selected AbstractsEcohydrology of a seasonal wetland in the Rift Valley: ecological characterization of Lake SolaiAFRICAN JOURNAL OF ECOLOGY, Issue 3 2009Tanguy De Bock Abstract The following research describes through an ecohydrological approach, the first assessment of the ecology of Lake Solai, with a particular emphasis on the vegetation. Lake Solai is located 50 km north of Nakuru in the Rift Valley in Kenya at E36°80,,36°84, to N00°05,,00°08,. It is a shallow lake that follows a very peculiar seasonal water regime, and that faces conflicts between agriculture and conservation water users. In the upper catchment, an overview of the agricultural practices was implemented and river water uses were identified to assess river flows. Crops/grassland and woodland/shrubland were the major land uses, covering c. 65% of the catchment. Closer to the lake, vegetation samples were collected around the lake together with samples of environmental factors such as soil and water quality. Thirteen vegetation communities were identified within four main zonations: forest, grassland, river inlet and rocky outcrop. These communities showed abundance, distribution and diversity determined mostly by the human pressures, the flooding periods and the salinity. Cynodon, Cyperus and Sporobolus genera were the most abundant. Résumé La recherche suivante décrit, par une approche éco-hydrologique, la première évaluation de l'écologie du lac Solai, en insistant particulièrement sur la végétation. Le lac Solai est situéà 50 km au nord de Nakuru, dans la vallée du Rift kényane, et ses coordonnées sont 36°80,,36°84E à 00°05,,00°08,N. C'est un lac peu profond qui est soumis à un régime hydrique saisonnier très particulier et qui est confrontéà des conflits entre acteurs agricoles et de conservation de la nature. En amont du bassin, une étude des pratiques agricoles a été effectuée, puis les utilisations de l'eau identifiées pour évaluer les débits des rivières. Les cultures/prairies et les forêts/broussailles étaient les principales utilisations des terres et couvraient environ 65% du bassin versant. Plus en aval, des échantillons de végétation ont été récoltés le long du lac, en même temps que des échantillons de facteurs environnementaux tels que le sol et l'eau. Treize communautés végétales ont été identifiées au sein de quatre zones principales: forêt, prairie, rivière entrante et affleurement rocheux. Ces communautés présentaient une abondance, une distribution et une diversité qui étaient principalement déterminées par les pressions humaines, les périodes d'inondation et la salinité. Les genres Cynodon, Cyperus et Sporobolusétaient les plus abondants. [source] Variation in gametophyte dominance in populations of Chondrus verrucosus (Gigartinaceae, Rhodophyta)PHYCOLOGICAL RESEARCH, Issue 4 2008Alecia Bellgrove SUMMARY We describe the abundance, including spatial and temporal variability, of phases of the isomorphic Chondrus verrucosus Mikami from Japan. Chondrus verrucosus occurred in a dense (,90% cover) and temporally stable bed on a small, isolated rocky outcrop (Oyakoiwa) in Shizuoka Prefecture. Small vegetative fronds were always much more abundant than large vegetative and fertile fronds over the spring to late summer periods in 1999 and 2000. Over the same period, fertile carposporophytic fronds were generally more abundant than fertile tetrasporophytic fronds, and fertile male fronds appeared infrequently at low densities. Using the resorcinol-acetal test, we determined the proportion of gametophytes and tetrasporophytes in three populations of C. verrucosus: Oyakoiwa and Noroshi (Shizuoka) in the summers of 1999 and 2000 and Kamehana Point (Miyagi) in autumn 2000. All populations had a significantly higher proportion of gametophytes than tetrasporophytes in both years, although gametophytic proportions were lower at Noroshi (,70%) than at Oyakoiwa (,80%) and Kamehana Point (,97%). However, examination of all isolated individuals sampled on Noroshi showed equal proportions of each phase in 1999, but gametophyte dominance (74%) in 2000. Differences in dispersal and spore production between phases are discussed as mechanisms potentially contributing to variation in gametophyte dominance. [source] A new species of Anthurium (Araceae) from Espírito Santo State, eastern BrazilFEDDES REPERTORIUM, Issue 1-2 2005E. G. Gonçalves Dr. A new species of Anthurium (A. viridispathum E.G.Gonç., sp. nova) is described and illustrated. It occurs in rocky outcrops in Espírito Santo state, eastern Brazil. It seems to be closer to AnthuriumvalidinerviumEngl., but differs in the primary lateral veins departing from the midrib in a more obtuse angle (45,55° not 30°), much wider spathe (2,2.3 times longer than broad, not 5,6) and inflorescenes longer than leaves (much shorter in A. validinervium). Anthurium viridispathum is tentavely placed in the section UrospadixEngl. subsection ObscureviridiaEngl. (© 2005 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) Eine neue Art der Gattung Anthurium (Araceae) aus dem Staat Espírito Santo, Ostbrasilien Eine neue Art der Gattung Anthurium (A. viridispathum E.G.Gonç., sp. nova) wird beschrieben und abgebildet. Sie findet sich in felsigen Aufschlüssen im Bundesstaat Espírito Santo, Ostbrasilien. Sie ist eng verwandt mit Anthurium validinerviumEngl., untercheidet sich aber durch primäre Seitenadern, die von der Mittelrippe in einem größeren Winkel (45,55°, nicht 30°) abgehen, einer viel breiteren Spatha (2,2,3 mal länger als breit, nicht 5,6 mal) und Blütenständen länger als die Blätter (wesentlich kürzer in A. viridinervium). Anthuriumviridispathum wird unter Vorbehalt in die sect. UrospadixEngl. subsect. ObscureviridiaEngl. gestellt. [source] Basking site and water depth selection by gharial Gavialis gangeticus Gmelin 1789 (Crocodylia, Reptilia) in National Chambal Sanctuary, India and its implication for river conservationAQUATIC CONSERVATION: MARINE AND FRESHWATER ECOSYSTEMS, Issue 2 2009Syed Ainul Hussain Abstract 1.The species diversity of inland waters is among the most threatened of all ecosystems and in many parts of the world it is in continuing and accelerating decline. Such decline could be restrained by acknowledging the scope of target species, so that all relevant stages in their life cycle are considered. 2.The gharial Gavialis gangeticus is a prominent riverine species of the Indus, Ganges, Brahmaputra and Mahanadi river systems that is becoming increasingly rare due to reduction in water flow and available nesting beaches, modification of river morphology and increased mortality in fishing nets. Despite these threats, scientific information on habitat selection by gharial is still inadequate, which hinders conservation measures. 3.This paper presents the population status, basking site selection and water depth preferences of different size-classes of gharial based on a study conducted in the National Chambal Sanctuary, India. 4.Between 1992 and 2007 a 40% decline in the gharial population was observed in the National Chambal Sanctuary. The decline was prominent in the recruitment class (<120,cm), which primarily comes from the nests laid in the wild, and also in sub-adults (>180 to 270,cm) comprising both wild and reintroduced gharial. 5.Along the Chambal River, gharial preferred sandy parts of the river banks and sand bars for basking and showed less preference for rocky river banks and rocky outcrops. Clay river banks were least preferred. 6.Juvenile gharials <120,cm and 120,180,cm preferred water depths 1,3,m and 2,3,m, respectively. Gharial >180,cm (including sub-adults and adults) preferred water depths >4,m. 7.Increasing demands for sand for development activities, and water abstraction for irrigation and energy generation coupled with mortality in fishing nets, are likely to affect gharial and other aquatic species, and steps need to be taken to maintain the minimum river flow necessary to sustain ecosystem processes. Copyright © 2009 John Wiley & Sons, Ltd. [source] Microhabitat relationships among five lizard species associated with granite outcrops in fragmented agricultural landscapes of south-eastern AustraliaAUSTRAL ECOLOGY, Issue 2 2010DAMIAN R. MICHAEL Abstract A fundamental part of developing effective biodiversity conservation is to understand what factors affect the distribution and abundance of particular species. However, there is a paucity of data on ecological requirements and habitat relationships for many species, especially for groups such as reptiles. Furthermore, it is not clear whether habitat relationships for particular species in a given environment are transferable to other environments within their geographical range. This has implications for the type of ,landscape model' used to guide management decisions in different environments worldwide. To test the hypothesis that species-specific habitat relationships are transferable to other environments, we present microhabitat models for five common lizard species from a poorly studied habitat , insular granite outcrops, and then compared these relationships with studies from other environments in south-eastern Australia. We recorded twelve species from five families, representing 699 individuals, from 44 outcrops in the south-west slopes of New South Wales. Five lizard species were abundant and accounted for 95% of all observations: Egernia striolata, Ctenotus robustus, Cryptoblepharus carnabyi, Morethia boulengeri and Carlia tetradactyla (Scincidae). Linear regression modelling revealed suites of different variables related to the abundance patterns of individual species, some of which were broadly congruent with those measured for each species in other environments. However, additional variables, particular to rocky environments, were found to relate to reptile abundance in this environment. This finding means that species' habitat relationships in one habitat may not be readily transferable to other environments, even those relatively close by. Based on these data, management decisions targeting reptile conservation in agricultural landscapes, which contain rocky outcrops, will be best guided by landscape models that not only recognize gradients in habitat suitability, but are also flexible enough to incorporate intraspecies habitat variability. [source] | ||||||||||