Showing papers in "Open Journal of Ecology in 2015"

Phytoremediation Mechanisms of Heavy Metal Contaminated Soils: A Review

Abstract: Phytoremediation is a green emerging technology used to remove pollutants from environment components. Mechanisms used to remediate soils contaminated by heavy metal are: phytoextraction, phytostabilisation, phytovolatilization and rhizofiltration. The two first mechanisms are the most reliable. Many factors influence the choice of the suitable phytoremediation strategy for soil decontamination. It depends on soil properties, heavy metal levels and characteristics, plant species and climatic conditions. The present review discusses factors affecting heavy metals uptake by plant species, the different phytoremediation strategies of heavy metal contaminated soils and the advantages and disadvantages of phytoremediation and each of its mechanisms.

Marine Species Introduced on the French Channel-Atlantic Coasts: A Review of Main Biological Invasions and Impacts

Abstract: The impacts of anthropogenisation modify permanently the distribution p atterns of brackish and marine species. Globalization leads to a rapid increase of the numbers of introduced species anywhere in the world. Biological invasions often result in significant losses in the economic value, biological diversity and function of invaded ecosystems. This review presents the main pathways of introduction of non-indigenous species and the main benthic taxonomic groups being established and/or invasive along the French Channel-Atlantic coasts. A focus is put on main invasive marine species in the intertidal and subtidal zones of Brittany (France), among macroalgae (Sargassum muticum, Grateloupia turuturu, Undaria pinnatifida, Codium fragile and Gracilaria vermiculophylla), halophytes (Spartina alterniflora) and benthic invertebrates (Mollusks: Crepidula fornicata, Crassostrea gigas and Venerupis philippinarum). The species biology, introduction vectors, reproductive and dispersal capacities are considered, together with proliferation patterns along the Channel-Atlantic coasts. The ecological impacts of these species on the environment are also described, as well as the European regulations existing to limit alien species introduction and some examples of struggle against the invaders including eradication trials and biomass valorization. Last, the on-going impacts of global changes on alien species invasiveness along the Channel-Atlantic coasts are discussed.

Geodiversity Examples of Morocco: From Inventory to Regional Geotourism Development

Abstract: The soil and subsoil of Morocco are rich in geological phenomena that bear the imprint of a history which goes back in time more than 2000 million years. Very many geologically remarkable sites exposed in accessible outcrops, with good quality remained unknown to the general public and therefore deserved to be vulgarized. It is a memory to acquaint the present generations but also to preserve for future generations. In total, a rich geological heritage in many ways: Varied landscapes, international stratotypes, various geological structures, varied rocks, mineral associations, a huge procession offossiles, remnants of oceanic crust (ophiolites) among oldests ones in the world (800 my), etc. For this geological heritage, an approach of an overall inventory is needed, both regionally and nationally, taking into account all the skills of the earth sciences. This will put the item on the natural (geological) potentialities as a lever for sustainable regional development. For this, it is necessary to implement a strategy of “geoconservation” for the preservation and assessment of the geological heritage. A website “lithotheque du Maroc” is under construction.

Fuel Oil Production from Two-Stage Pyrolysis-Catalytic Reforming of Brominated High Impact Polystyrene Using Zeolite and Iron Oxide Loaded Zeolite Catalysts

Abstract: The experiments of two-stage pyrolysis and catalytic reforming of high impact polystyrene (HIPS) containing brominated flame retardants and antimony trioxide (Sb2O3) were conducted in the presence of four zeolite catalysts in order to remove the bromine content from the derived oil products. The four catalysts used were natural zeolite (NZ), iron oxide loaded natural zeolite (Fe-NZ), HY zeolite (YZ) and iron oxide loaded HY zeolite (Fe-NZ). The effect of catalyst types on the product yield, the gas and oil product composition and the debromination efficiency of the oil products was evaluated in details. The results showed that the loading of iron oxides reduced the pore size and surface areas of natural zeolite and HY zeolite. Regardless of the presence of catalysts, the single-ring aromatic compounds were the main components of the oil products, such as ethylbenzene, toluene, styrene and cumene. Meanwhile, when YZ and Fe-YZ were used, the two-ring and multi-ring aromatic compounds in the oils, as well as the yield of gas products, significantly increased at the expense of valuable single-ring aromatic compounds. Furthermore, in terms of the debromination performance of the oil products, Fe-NZ and Fe-YZ were better than NZ and YZ, duo to the loading of iron oxide, which could react with derived HBr and then remove more bromine from the oil products.

Butterfly Species Diversity and Abundance in University of Ibadan Botanical Garden, Nigeria

Abstract: Understanding the significance of butterflies in an ecosystem as an environmental healthy indicator and pollination of flowering plants is crucial to achieving sustainability and conservation of floral diversity. The aim of the study was to investigate the butterfly species diversity and abundance and compare the relationship between physical factor and butterfly species. Line transect were used to survey three habitats around botanical garden with scooped-net between June and July, 2010. Diversity varied from habitat to habitat. A checklist was made comprising a total of 57 butterfly species that were surveyed belonging to 9 families. There was a relationship between temperature and butterfly species diversity and abundance. There was no correlation between physical factors (relative humidity and temperature) and the total number of species and families. Moreover, butterfly numbers were not related to relative humidity in any species and family. However, temperature was significantly correlated with species. Therefore, understanding of the factors that affect butterfly species diversity and abundance in University of Ibadan Botanical Garden is important for conservation.

The Evolution of a Karst Rocky Desertification Land Ecosystem and Its Driving Forces in the Houzhaihe Area, China

Abstract: Understanding the evolution of karst rocky desertification (KRD) quantitatively is essential to obtain objective knowledge about the concept of KRD and the form reason of KRD, and is useful to restore KRD land. Houzhaihe area located in central plateau in Guizhou Province was studied here as a representative assemblage landform and its KRD’ s evolution and driving factors were studied, based mainly on high-resolution remote sensing image in 1963, 1978, 2005 and 2010. The KRD land comprises light KRD, moderate KRD and severe KRD. The results demonstrated that the evolution process of KRD can be divided into four modes such as unchanged, weakened, fluctuated and aggravated in the study area. The KRD with no changes from 1963 to 2010, namely, unchanged mode, accounted for 43.76% of the total area of the KRD in 2010; it distributed in the area with the slope of 15° - 25° and >25° basically. Furthermore, the severe KRD distributed mainly in the areas within 300 - 600 m distance from settlement; when the distance away from the rural settlements was more than 900 m, the severe KRD declined, and its proportion was 28.6% and 10.6% in 1963 and 2010 respectively. In the peak-cluster depressions, located in central study area, the slope cropland with slope of 15° - 25° was still abounding, and was seriously rocky desertification generally. So, we propose that the existence of a large number of slope croplands is still the major driving factor of land rocky desertification. Therefore, for the rocky desertification control, the authors consider that the focal point is to alter the land use of steep-slope cropland at present.

The Impact of Grazing on Plant Natural Regeneration in Northern Slopes of Mount Kilimanjaro, Tanzania

Abstract: Livestock grazing is considered to be of great ecological importance in terrestrial ecosystems if sustained at acceptable levels. Overgrazing has ecological ramifications which lead to degradation of the ecosystem. This has become a problem in many parts of Tanzania. A study was conducted in Northen Slopes of Mount Kilimajaro in order to examine the impact of grazing on natural regeneration of the grazed vegetation. This paper is guided by the hypothesis that the species richness, species diversity and density of regenerants vary across grazing intensities. The study area was divided into four zones as per grazing intensity namely heavily grazed areas, moderately grazed, least grazed and ungrazed areas. Ten rectangular quadrats of 20 m × 25 m were established in each zone, making a total of 40 quadrats in the entire study area. A stratified random sampling procedure was used in locating quadrats in each zone of grazing intensity whereby two subquadrats of 2 m × 5 m were nested in bigger quadrats. Natural regeneration was assessed in terms of species diversity and density of seedlings, saplings and poles. Results indicate that species regeneration varied among areas with different grazing intensity. The variations of seedlings and saplings density among areas with different grazing intensity were statistically significant. The species diversity of regenerants differed significantly among areas with different grazing intensity. Keeping the grazing intensity at low and moderate levels will stimulate more plant growth and diversity as opposed to heavy grazing which will lead to vegetation retrogression.

The Impact of Available Nitrogen Deficiency on Long-Term Changes in the Lake Kinneret Ecosystem

Abstract: Lake Kinneret Ecosystem structure has undergone significant modification since early 1990s. Scientists have indicated several causative factors for those long-term changes. The sharp decline of Peridinium and the upset of Cyanobacteria are the major changes. Several options were suggested as the reason for those changes. Among others are the followings: high amplitude of water level fluctuations, global warming, fisheries management, salts diversion, onset and offset of beach vegetation, anthropogenic operations in the drainage basin, allelopathic trait of algal competition, etc. It was suggested that the reduction of ammonia supply from the Hula Valley resulted in the conversion of the land from lake and swamps covered to agriculture followed by elimination of treated domestic sewage and fishponds effluents enhanced deficiency of available N in Lake Kinneret. This paper evaluates the impact of available Nitrogen decline which enhanced Kinneret ecosystem modifications.

Foraminifera as Environmental Condition Indicators in Todos os Santos Bay (Bahia, Brazil)

Abstract: The environmental quality of the marine area close to the Landulpho Alves Oil Refinery situated in Todosos Santos Bay (Bahia, Brazil) was assessed by statistical methods on foraminiferal assemblages, with species tolerant to low continental influence such as Ammonia tepida, Elphidium excavatum, Pseudononion atlanticum and Quinqueloculina spp., and to high organic matter such as Buliminella elegantissima and Bulimina marginata. We have found that Bolivina pulchella, Pseudononion atlanticum, Fursenkoina pontoni, Buliminella elegantissima, Bolivina striatula, Bulimina marginata, Quinqueloculina spp., Ammonia tepida, and Elphidium excavatum are opportunistic and tolerant to high levels of accumulated organic matter, and are associated to stations 6, 17, 18, 19, 21, 22, 23, 24, and 25, located mainly in the southern, outermost part of the Bay.

Fruit Phenology of Tree Species and Chimpanzees’ Choice of Consumption in Kalinzu Forest Reserve, Uganda

Abstract: One hundred and eighteen (118) tree species were identified, among which 58 species produced fruit within the two-year study. Fruit of only 26.3% of the latter is eaten by chimpanzees. The consumption of each of these fruits was generally low, with only two species constituting more than 25% consumption. Only about 1.7% of woody biomass is relied upon by chimpanzees in Kalinzu for food. The major tree species in chimpanzee diet monitored showed that fruit production varies monthly and seasonally. Apart from Musanga leo-errerae and Ficus spp. whose fruiting was consistent throughout the year, general fruit phenology was positively correlated with rainfall. Only three species namely: Craterispermum laurinum, Aframomum angustifolium and Beilschmiedia ugandensis produced fruit in the dry seasons. Correlation between fruit availability and consumption was significantly positive for only one species, Landlophia dawei. This indicated that frugivory of chimpanzees in Kalinzu was not opportunistic; they search for what they like to eat. Chimpanzees would have to range furthest in periods of scarcity and asynchronous fruiting hence a lot of energy expenditure in the food search alone. Therefore, diversity in fruit phenology is important for chimpanzees’ energy conservation, health and survival. Selective logging and other selective human activities that involve cutting down trees that are palatable would in future affect the food diversity and consequently the health of frugivores if not done sustainably. Since patterns of fruit phenology are also linked to patterns of rainfall, changes in the former can assist in predicting the influence of climate change on food availability for big frugivores like chimpanzees.

Conservation of Forestry Biomass with the Use of Alternative Resource

Abstract: The effect of the alternative resource and time delay on conservation of forestry biomass is studied by considering a nonlinear mathematical model. In this paper, interaction between forestry biomass, industrialization pressure, toxicant pressure and technological effort is proposed and analysed. We find out the critical value of delay and observe that there is Hopf bifurcation. Using the normal form theory and the center manifold theorem, we determine the stability and direction of the bifurcating periodic solutions. Numerical simulations are given to illustrate the analytical results.

Regulated Fishery Is Beneficial for the Sustainability of Fish Population in Lake Kinneret (Israel)

Abstract: Analysis of long-term data-sets of limnological and ichthyological features of the Lake Kinneret ecosystem structure revealed evidence that the decline of fish landings during 2007-2008 was not an unpredicted crisis and included only Tilapias, and mostly S. galilaeus. Several factors were found to be responsible for the decline and recovery afterwards: decline of stocking, enhancement of population size of food competitors (Bleaks), the use of smaller mesh size of fishing nets, increase of predation pressure by Cormorants, the burst of Viral Disease, natural cyclic oscillation of ENSO event and its higher frequencies and intensities during the 2000’s. Therefore, recommendations aimed at ceased fishing are not justified and fishery continuation is correct: renewal of Bleaks fishing effort, improvement of fishing legislations, enforcement and management of fish stocking, and efficient implementation of Cormorants deportation.

Optimal Control of a Threatened Wildebeest-Lion Prey-Predator System in the Serengeti Ecosystem

Abstract: We develop a two-species prey-predator model in which prey is wildebeest and predator is lion. The threats to wildebeest are poaching and drought while to lion are retaliatory killing and drought. The system is found in the Serengeti ecosystem. Optimal control theory is applied to investigate optimal strategies for controlling the threats in the system where anti-poaching patrols are used for poaching, construction of strong bomas for retaliatory killing and construction of dams for drought control. The possible impact of using a combination of the three controls either one at a time or two at a time on the threats facing the system is also examined. We observe that the best result is achieved by using all controls at the same time, where a combined approach in tackling threats to yield optimal results is a good approach in the management of wildlife populations.

Explaining Design Dimensions of Ecological Greenways

Abstract: Design of greenways is one of the most important planning tools in the promotion of quality of life of the city residents. Greenways are necessary due to their major role in increase of air quality and positive changes in the climate of the urban environments for keeping the environmental quality of the cities and considerably increasing aesthetic values of these environments. Protection of natural ecological systems, provision of extensive recreational opportunities for people in urban regions and rural districts, provision of economic benefits and protection of cultural values and historical heritage are the advantages of designing and creating greenways inside cities. The present paper which was conducted with descriptive-analytical method tried to explain design dimensions of ecological greenways in three urban physical, environmental and social-economic systems by studying suitable experimental concepts and samples in the world. In this regard, this paper studied five main goals of designing greenways: promotion of local and urban accesses with greenways, aesthetic aspects of urban landscapes, improvement of performance and distribution of activities by creating greenways, increase of efficiency and environmental aspects in the city and revival of social values considering economic sustainability and in this regard design strategies and policies were presented for each one of them based on these goals.

Silver Carp (Hypophthalmichthys molitrix, Val. 1844) Stocking in Lake Kinneret (Israel)

Abstract: Silver Carp (SC) (Hypophthalmichthys molitrix, Valenciennes, 1844) is a worldwide common fish for aquaculture and stocking in lakes and reservoirs. The fish is distributed through rivers, aquaculture and stocking in about 90 countries around the world. SC was first introduced into Lake Kinneret in 1969 and continues onwards. Total number of stocked fingerlings (1969-2013) was 18.5 × 106 (average: 441 × 103 per year). The total catch (tons) of SC in Lake Kinneret was 3218 tons, average: 75 t/year. Studies on SC in East Lake, China, revealed that the fish was a phytoplanktivorous and percentage of consumed phytoplankton varied between 83% - 91% where Microcystis was the major item. In Lake Kinneret, the effects of SC and the Cichlid, Galilee St. Peters Fish (S. galilaeus) on Plankton resources are not independent and potentially competitors. SC is also known as efficient consumer of Microcystis. It was found that environmental conditions in Lake Kinneret were optimal for reasonable growth and recruitment of this fish to commercial fishery. The SC did not reproduce in Lake Kinneret and we recommended introducing annually 600 - 1000 × 103 fingerlings for the benefit of water quality protection and fishermen income.

Influence of Floodplain Area on Fish Species Richness in Waterbodies of the Chao Phraya River Basin, Thailand

Abstract: River-floodplain ecosystems are in delicate balance and are impacted by even minor changes in water availability. In this study, we surveyed fish assemblages and investigated environmental and landscape parameters in a total of 135 floodplain waterbodies (rivers, diversion canals, ponds, irrigation ditches, paddy fields, and wetlands) in the Chao Phraya River Basin in rainy (September 2014) and dry (March 2015) seasons. Factors affecting fish species richness in each type of waterbody were analyzed using generalized linear mixed models. Floodplain area around each surveyed waterbody was a major factor determining fish species richness in rivers, diversion canals, and ponds in the region. The contribution of floodplain area was equivalent to that of hydrology (current velocity, water depth) and water quality (dissolved oxygen, turbidity) in the waterbodies. The population of juvenile fishes was increased in temporarily connected floodplain waterbodies to main rivers compared with isolated waterbodies, and fluvial and lacustrine fishes were observed in the temporary inundated floodplain waterbodies during the rainy season. The high dependence of fish species richness on floodplain area in the region appeared to be a result of the use of inundated floodplains by fish species to forage and breed. Our results highlight the impact of flood control measures that reduces floodplain area. These measures must be reviewed to ensure the conservation of fish biodiversity in the Chao Phraya River Basin, one of the world’s most threatened floodplain systems.

Mugilids (Mugil cepalus, Linnaeus, 1758; Liza ramada, Risso, 1810) Stocking in Lake Kinneret (Israel)

Abstract: Stocking of Lake Kinneret by exotic fish species (Mugilids: Mugil cephalus and Liza ramada) started in 1958. The rational stocking of Lake Kinneret with Mugilids was double functioned: To improve fishermen income and the water quality in the lake. Mugilids are chosen as introduction target because their market value is high, the fish cannot reproduce in the lake and fingerlings are low cost available. During 1960-2015, 56.2 million fingerlings were introduced into the lake approximately averaged one million per year of M. cephalus (MC) and L. ramada (LR). The study of the Mugilids food composition has indicated consumption of suspensoids, mostly detritial organic particles. Therefore no damage to water quality is suggested. The best fitness between recruitment to Dock on Side landings and stocking capacity was evaluated at 3 years interval. Differences were found between recruitments of MC and LR to commercial catches by individual averaged age and weight. The long term success of Mugilid introduction to Lake Kinneret is confirmed.

Evaluation of Tourism Status in Sustainable Rural Development by Reynard Model (Case Study: Pa Ghaleh Village, Mamasani County, Iran)

Abstract: The greatest service industry and income gainer throughout the world occupies a special role and position in developing geographical areas. This study attempts to use “Reynard” model to investigate the role of tourism and its effects on the development of rural settlements with emphasis on Pa Ggaleh Village, which is one of the environs in Mamasani, Iran. Due to its historical and religious attractions and natural and cultural landscapes, this village is highly significant and has the potential to become a tourism hub and attract tourists. The methodology applied in this research is cross-sectional. Tourism potentials of Pa Ghaleh village are identified and evaluated in this study. Geological maps, topographies and field data are used to evaluate the district attractions. Their tourism potentials are also evaluated and rated using Reynard model. According to the sub-criteria of rarity and historical geography, the research results indicate that scientific value has the highest rank. In other words, tourism places in Pa Ghaleh village include 72% of scientific value, 0.59% of added value and 0.57% of compound value.

Experimental Study of the Aphanizomenon ovalisporum Response to Nitrogen Fertilization in the Sub-Tropical Eu-Meso-Trophic Lake Kinneret (Israel)

Abstract: First record of a bloom of filamentous-heterocystous nitrogen fixer cyanobacterium, Aphanizomenon ovalisporum, was documented in the summer of1994 inLake Kinneret (Israel) Awareness of such a bloom outbreak was predicted earlier based on documentation of Nitrogen deficiency and Phosphorus Sufficiency developed conditions The concept of Nitrogen fertilization aimed at suppression of Nitrogen fixers Cyanobacteria was worldwide discussed and successfully implemented, but mostly in temperate oligotrophic lake ecosystems This paper presents an experimental testing of this concept by additional Nitrogen The results of the present study did not verify this hypothesis probably related to the ecological differences between Kinneret and the temperate ecosystems and using only one factor (Nitrogen) to test it

Study of the Population Dynamics of the Olive Fly, Bactrocera oleae Rossi. (Diptera, Tephritidae) in the Region of Essaouira

Abstract: The Bactrocera oleae Rossi fly is the most important olive pest. It is of major economic importance in the olive production area of Essaouira, where weather conditions are optimal for the conduct of the various stages of its life cycle. The lack of phytosanitary treatments worsens this situation. The development of the larval stages and different generations are related to the phenological stages of the olive and are controlled by changes in habitat conditions. Trapping of adult males by Deltas traps baited with sex pheromone, at the four study sites, has identified some characteristics of the evolution of the adult populations’ flight dynamics. Our main results show a decreasing gradient of early emergences of different stages from the coast to the continental areas as well as the absence of the summer generation at the inner station. Soil analysis in the two stations showed that the hypogenous pupae wintering in the soil survive until June. Knowledge of the factors involved in the bio-ecology of the olive fly and the phenology of the host allows the elaboration of monitoring/ warning calendars, and phytosanitary measures in order to establish an IPM program adapted to the requirements of olive orchards in the region.

Taxonomic Diversity and Taxonomic Dominance: The Example of Forest Plantations in South-Central Chile

Abstract: The study describes an analysis of the impact of plantation forestry on the taxonomic diversity of plants in south-central Chile. In this biodiversity hotspot, plantations of non-native species like Pinus radiata D. Don, Eucalyptus globules Labill. and Populus nigra L. have largely replaced native deciduous and sclerophyllous forests. The study compares taxonomic diversity of commercial plantations and native forests using taxonomic distinctness and diversity and the Simpson diversity index. Most of these indexes attest a considerably reduced taxonomic diversity to plantations. However, taxonomic distinctness values for P. radiata plantations seem to contradict other indexes at first glance. It is shown that the higher values of taxonomic distinctness of P. radiata plantations come from taxonomic dominance. Taxonomic dominance describes the fact that P. radiate—a member of the infradivison of Gymnospermae-bears only little taxonomic resemblance to other plants, which are Angiospermae. Thus, it strongly dominates the taxonomic distinctness index and the high taxonomic resemblance of other plant within its plots is neglected. Indexes are developed that identify such dominant species and adjust for taxonomic dominance in taxonomic diversity analyses. After this adjustment, all indexes provide a coherent image on taxonomic diversity. Plantation forestry produces a considerable decline of taxonomic diversity. Taxonomic diversity analysis provides valuable insights in biodiversity impacts and complements standard analyses.

Thermal Preference by Mesocyclops ogunnus (Onabamiro, 1957)

Abstract: In this work, the thermal response of Mesocyclops ogunnus was experimentally studied. Temperature was the only one parameter that was tested. Other parameters, such as food quality and availability, light conditions, predation pressure, and water mass motions were not included in the study. Organisms were collected in Lake Kinneret and the experiments were carried out under diffused light, 12/12 hours light/dark conditions. In the experimental system, the organisms were exposed to different temperatures of 15˚C, 25˚C, 27˚C, and 30˚C with open pathway to migrate according to temperature preference. The preference of upper thermal range (25˚C, 27˚C, 30˚C) by copepodite and adult stages was documented.

The Contribution of Tanzanian National Parks in Controlling the Vectors of Sleeping Sickness

Abstract: This paper summarises efforts to control Sleeping sickness [Human African Trypanosomiasis (HAT)] by Tsetse flies and Trypanosomiaisis (T & T) control for the 7 consecutive years although started a decade ago in Tanzania National Parks (TANAPA). These efforts are critical for curbing HAT incidences and HAT epidemics. HAT cases have had profound negative impacts on human health, affecting local residents and international travel as well as tourism industry resulting into human and animal health burden and reduction in tourism income. Understanding the current efforts is essential in the proper planning and decision making on developing effective control strategy against T & T control. In this paper, we summarize the recent efforts in the control of T & T in National Parks and discuss the constraints faced. The information will enable TANAPA and other concerned authorities to make informed decision on optimal ways of controlling HAT in National Parks. The results show that much control efforts have so far concentrated in Serengeti, Ruaha, Tarangire and Katavi National Parks where tsetse fly challenges are high. A total 21,143 (average 3020) Insecticide Treated Targets (ITT) were deployed in different areas in the parks and 82,899 (average 20,725) cars entering these parks were sprayed from 2007/2008 to 2014/2015 and 2007/2008 to 2010/2011 respectively. Deployed ITTs lead to a drastic reduction of FTDs of the two dominant tsetse species to 1.3 and 1.4 of G. swynnertoni and G. pallidipes respectively, and the decline was significant at P = 0.011. The major challenges faced include tsetse re-invasion in controlled areas; resurgence of HAT cases when control efforts are relaxed, ITT maintenance and inadequate health education programs. The control strategy should be continuous and scaled up as failure to implement an effective and sustainable system for HAT control will increase the risk of new epidemic that would impede tourism development.

Nitrogen and Phosphorus Dynamics in the Shallow Lake Agmon (Hula Valley, Israel)

Abstract: Lake Agmon is a newly created shallow body of water which is a principle component of a reclamation project (Hula Project, HP) in the Hula Valley (Israel). The objectives of the HP are aimed at Lake Kinneret water quality protection, and improvements of the hydrological, and agricultural managements within the entire Hula Valley including the eco-touristic quality of the Agmon site. Thirteen years of research and monitoring, are summarized by focusing on nitrogen and phosphorus dynamics. It was found that the decay of submerged vegetation was the major P contribution to the Agmon effluents as dissolved (TDP) and plant debris particle forms. Peat soil gypsum dissolution contribute sulfate to drained waters and consequently to Agmon outflows. The Agmon system is operated as a nitrogen sink by de-nitrification and particulate sedimentation and contributor of plant mediated phosphorus. In the reconstructed Jordan flows into the Agmon, a stable composition of nutrients was indicated but those of the peat drainage and the lake effluents represented the higher level in winter and lower in summer. Anoxic conditions in the water column enhancing sulfate reduction are negligible and rarely observed. The Agmon merit to the reclamation process was achieved.

Vegetation Analysis and Soil Characteristics on Two Species of Genus Achillea Growing in Egyptian Desert

Abstract: The present study provides a vegetation analysis and species distribution at 50 sites, emphasizing the environmental factors that affect species distribution. A total of 74 plant species belonging to 67 genera and related to 23 families of vascular plants are recorded. Asteraceae, Poaceae, Chenopodiaceae, Brassicaceae, Fabaceae and Zygophyllaceae are the largest families, and therophytes (41.89) and chamaephytes (24.32%) are the most frequent, indicating a typical desert life-form spectrum. Chorological analysis revealed that 25 of the studied species were Mediterranean taxa, Saharo-Sindian chorotypes, either pure or penetrated into other regions, comprised 47 species. After application of the TWINSPAN and DCA programs, 4 vegetation groups (A-D) were identified, groups A and B were dominated by Achillea santolina, group C was codominated by Zygophyllm coccinum and Launaea spinosa and group D was dominated by Leptadenia pyrotechnica. Groups A and B may represent the vegetation types of the Western Mediterranean coast of Egypt, while groups C and D may represent the Wadi Hagul. The linear correlation of soil variables with the importance values of some dominant species and the application of Canonical Correspondence Analysis (CCA-biplot) indicates significant associations between the floristic composition of the studied area and the edaphic factors such as electrical conductivity, pH, calcium carbonate, sulphates, bicarbonate, cations (Na+, K+, Ca++ and Mg++) and PAR.

Partial Formalization: An Approach for Critical Analysis of Definitions and Methods Used in Bulk Extraction-Based Molecular Microbial Ecology

Abstract: Partial formalization, which involves the development of deductive connections among statements, can be used to examine assumptions, definitions and related methodologies that are used in science. This approach has been applied to the study of nucleic acids recovered from natural microbial assemblages (NMA) by the use of bulk extraction. Six pools of bulk-extractable nucleic acids (BENA) are suggested to be present in a NMA: (pool 1) inactive microbes (abiotic-limited); (pool 2) inactive microbes (abiotic permissive, biotic-limited); (pool 3) dormant microbes (abiotic permissive, biotic-limited, but can become biotic permissive); (pool 4) in situ active microbes (the microbial community); (pool 5) viruses (virocells/virions/cryptic viral genomes); and (pool 6) extracellular nucleic acids including extracellular DNA (eDNA). Definitions for cells, the microbial community (in situ active cells), the rare biosphere, dormant cells (the microbial seed bank), viruses (virocells/virions/cryptic viral genomic), and diversity are presented, together with methodology suggested to allow their study. The word diversity will require at least 4 definitions, each involving a different methodology. These suggested definitions and methodologies should make it possible to make further advances in bulk extraction-based molecular microbial ecology.

Ecophysiology of Lake Kinneret (Israel) Zooplankton

Abstract: A summary of a long-term research of Lake Kinneret zooplankton distribution is presented. During 1969-2002 several prominent changes have been recorded in the Kinneret ecosystem. This paper is an attempt aimed at analyzing the impact of these ecological changes on the zooplankton communities. The impacts of Phytoplankton, Bacteria, Protozoa, Temperature, Nutrient composition and fish predation on zooplankton dynamics are analyzed. It was found that periodical fluctuations of zooplankton density were mostly affected by fish predation as well as by temperature increase and food availability. Ecological conditions in Lake Kinneret have been modified since early 1990’s and the new conditions were consequently accompanied by zooplankton Homeostatic response. Moreover, as a result of the ecological changes fish intensified their pressure on zoo-plankton. The flexibility of food resource preference by zooplankton enabled its existence but fish predation predominantly controlled their density.

Fish Diversity and Fish Assemblage Structure in Seagrass Meadows at Sikao Bay, Trang Province, Thailand

Abstract: We investigated the relationship between environmental variables as descriptors of the fish community, in terms of species diversity indices and fish assemblage patterns, in seagrass meadows at Sikao Bay, Trang Province, Thailand. Fish data and water quality parameters were collected from January to December 2012. A total of 10,596 fish specimens of 97 taxa in 48 families from four stations, Kham Bay (7°30'9.21''N, 99°18'7.67''E), Boonkong Bay (7°31'2.49''N, 99°17'40.09''E), Ban Pak Klong (7°36'17.67''N, 99°16'32.89''E) and Sai Cape (7°38'30.19''N, 99°14'49.85''E), were collected using gillnets of three different mesh sizes. The three most diverse families were Leiognathidae, Carangidae and Tetraodontidae, respectively. The dominant species were Atherinomorus duodecimalis, Sillago sihama and Pelates quadrilineatus. Specimens were highly abundant in July and less so in January and species richness was high in July and less so in March. Fish assemblages were classified into two patterns and the average of the Shannon index was 2.7. The environmental parameters in each month were analyzed by one-way ANOVA which did not show significant difference (P > 0.05) of pH, orthophosphate, wind speed and rainfall. Fish diversity and assemblage, and environmental parameters, were categorized into four groups. These could be promoted to local fisheries so that conservation programs cpuld be set up to ensure the ecological sustainability of seagrass meadows.

Ecological Devastation in Lake Victoria: Part B: Plankton and Fish Communities

Abstract: A few specimens of the exotic fish, Nile Perch, (Lates niloticus, Linnaeus 1758) were transferred into Lake Victoria in early 1950’s. In early 1980’s this fish occupied the Lake Victoria ecosystem eliminating the local endemic Haplochromines (app. 400 species). As a result of this change, together with intensification of pollution constrains from the catchment and dust deposition the ecology of Victoria’s ecosystem was modified: cyanobacteria replaced diatoms, anoxia enhanced, secchi depth became shallower, euphotic zone became thinner, fishery enhanced fully comprised of Nile Perch and Rastrineobola. The ecological significances are discussed and future propositions are presented.

Bayesian Estimation of Population Size via Capture-Recapture Model with Time Variation and Behavioral Response

Abstract: We consider the problem of population estimation using capture-recapture data, where capture probabilities can vary between sampling occasions and behavioural responses. The original model is not identifiable without further restrictions. The novelty of this article is to expand the current research practice by developing a hierarchical Bayesian approach with the assumption that the odds of recapture bears a constant relationship to the odds of initial capture. A real-data example of deer mice population is given to illustrate the proposed method. Three simulation studies are developed to inspect the performance of the proposed Bayesian estimates. Compared with the maximum likelihood estimates discussed in Chao et al. (2000), the hierarchical Bayesian estimate provides reasonably better population estimation with less mean square error; moreover, it is sturdy to underline relationship between the initial and re-capture probabilities. The sensitivity study shows that the proposed Bayesian approach is robust to the choice of hyper-parameters. The third simulation study reveals that both relative bias and relative RMSE approach zero as population size increases. A R-package is developed and used in both data example and simulation.