ID: 55402
Title: Carabid Beetles as indicators of current and historical land form and land use changes in wetlands
Author: A Georges
Editor: P S Ramakrishnan and Brij Gopal
Year: 1994
Publisher: International Scientific Publications, Vol 20, No 1-2, 1994
Source: Centre for Ecological Sciences
Reference: None
Subject: International Journal of Ecology and Environmental Sciences
Keywords: Invertebrates, biotic indicators, information, disturbance, reclaimed salt marshes
Abstract: The purpose of this paper was to compare iformation provided by Carabid beetle data to that provided by environmental parameters in order to evaluate the descriptive value of these invertebrates. Our objective was to suggest the use of invertebrates as " ecological indicators" in order to carry out studies regarding changes of the physical and biological characteristics of landscape either by natural phenomena or by human action. This methodology was applied to Marais poitevin (western France) where we have the opportunity to sample simultaneously in several sectors representing a range of land use history. Landscape patterns may be characterized in meaningful ways with the analysis of physical, environmental and geomorpholgoical parameters but such studies could be improved by information relating the distribution of Carabid beetles in the ecosystem. Invertebrate studies must be included in any classification of ecosystems for monitoring purposes, especially in cultivated lands where natural vegetation can not be used as the only biotic indicator.
Location: 241
Literature cited 1: None
Literature cited 2: None
ID: 55401
Title: Effect of drought, dams and fishing pressure on the fisheries of the Central delta on the Niger river
Author: Raymond Lae
Editor: P S Ramakrishnan and Brij Gopal
Year: 1994
Publisher: International Scientific Publications, Vol 20, No 1-2, 1994
Source: Centre for Ecological Sciences
Reference: None
Subject: International Journal of Ecology and Environmental Sciences
Keywords: Fish production, floodplains, hydrology, small-scale fisheries
Abstract: The fishing sector in Mali is now in a general slump. The Sahelian drought is primarily responsible for the low flooding, the decrease of floodplains and the lack of fish recruitment. During the lowest flood years, fish landings may decline by 40,000 metric tons. Dams built for agricultural or electrical use are also playing a part in reducing floodplain area: in 1989, the decrease in production was estimated at 5,000 tons, for landings of about 45,000 metric tons. During the dry season the stock of adults, which are particularly in danger of overfishing, is partly ensured by the releasing of water from dams which disturb fishing. The crisis which comes from a natural phenomenon has developed sociological and economical disruptions. The number of fishermen has doubled in the last 20 years and the catch per effort has reduced according to the decline of catches. Thus communal strife has increased.
Location: 241
Literature cited 1: None
Literature cited 2: None
ID: 55400
Title: Riparian influences on a tropical river ecosystem in Belize, Central America
Author: Patrick Kangas
Editor: P S Ramakrishnan and Brij Gopal
Year: 1994
Publisher: International Scientific Publications, Vol 20, No 1-2, 1994
Source: Centre for Ecological Sciences
Reference: None
Subject: International Journal of Ecology and Environmental Sciences
Keywords: River ecosystem, conservation, fish biology, ecosystem metabolism, deforestation, Riparian forest, Belize
Abstract: The ecology of the lower portion of the Sittee River in central Belize was studied with the long-term goal of making conservation recommendations. Data and ideas concerning riparian influences on the river ecosystem are presented. Based on analyses of diurnal curves of dissolved oxygen, aquatic ecosystem metabolism is heterotrophic with P/R ratios ranging from 0.42 to 0.86. This result suggests the importance of allochthonous energy sources. The presence of plant material and detritus in the stomachs of more than half of the large fish species also suggests inputs from riparian vegetation. Frugivory in certain fishes is indicated by the presence of seeds in their stomachs and by the use of fruit as bait by local fisherman. The potential effects of deforestation on these riparian forest-river interactions are discussed along with conservation options for preserving the river ecosystem .
Location: 241
Literature cited 1: None
Literature cited 2: None
ID: 55399
Title: Day-night variation of fish population in the mangrove of Celestun Lagoon, Mexico
Author: M E Vega-Cendejas, U Ordonez and M Hernanadez
Editor: P S Ramakrishnan and Brij Gopal
Year: 1994
Publisher: International Scientific Publications, Vol 20, No 1-2, 1994
Source: Centre for Ecological Sciences
Reference: None
Subject: International Journal of Ecology and Environmental Sciences
Keywords: Yucatan Peninsula, Block net, Mangrove, fish communities, Nursery areas, Avicennia germinans, Rhizophora mangle
Abstract: Celestun Lagoon,a coastal tropical ecosystem of the Yucatan Peninsula is fringed by mangrove forests, which make sampling of fishes a difficult task. Rotenone-drop net technique was applied in one site dominated by Avicennia germinans mixed with Rizophora mangle. In order to evaluate mangroves as nursery areas daylight and night collection of plankton, benthos and nekton were carried out and compared. Daylight abundances of different biological communities were greater. Results show daylight highest availability of foof resources for juvenile stages of fishes, while at night adult may forage out into adjacent areas.
Location: 241
Literature cited 1: None
Literature cited 2: None
ID: 55398
Title: Responses of emergent macrophytes to altered water level regimes in urban wetlands of Western Australia
Author: R H Froend, A J McComb
Editor: P S Ramakrishnan and Brij Gopal
Year: 1994
Publisher: International Scientific Publications, Vol 20, No 1-2, 1994
Source: Centre for Ecological Sciences
Reference: None
Subject: International Journal of Ecology and Environmental Sciences
Keywords: Groundwater abstraction, biomass, productivity, Typha angustifolia, Baumea articulata
Abstract: Groundwater abstraction, catchment alteration and climate change have the potential to alter the water regimes of wetlands on the sandy Swan Coastal Plain of south-western Australia. This paper is concerned with the distribution in relation to water level of the two most common emergent macrophytes of the area. Baumea articulata and Typha angustifolia. The distribution of these species is similar along transects in different wetlands. Their biomass distribution is a reflection of measured productivity. Their response is similar to different stable water levels under controlled conditions, maximum productivity for both being achieved where the water level is at the sediment surface. The conclusion that water regime explains distribution is modified in the field, where different producitivities were found in wetlands with the same water regimes, but different sediment nutrient concentrations and soil types. Typha fared better than Baumea when the two were grown in the same containers. In the field Typha was found to have replaced Baumea, when Baumea had been eliminated by altered water levels. It is concluded that changes in mean water levels alter species performance, and bring about changes in species composition of wetland vegetation.
Location: 241
Literature cited 1: None
Literature cited 2: None
ID: 55397
Title: Effects of salinity and sediment features on two emergent macrophytes in a coastal environment of Southern Brazil
Author: M E Araujo de Oliveira, M A L Verdade and B de A Carvalho
Editor: P S Ramakrishnan and Brij Gopal
Year: 1994
Publisher: International Scientific Publications, Vol 20, No 1-2, 1994
Source: Centre for Ecological Sciences
Reference: None
Subject: International Journal of Ecology and Environmental Sciences
Keywords: Scirpus californicus, Scirpus olneyi, biomass, ecophenic variation, Rio Grande do Sul
Abstract: Macrophytes variation was studied in homogeneous stands of Three-corner grass Scirpus olneyi, and of bulrush, Scirpus californicus, in a salt marsh in the Armazem Lagoon, and along the Tramandai River in the Coastal Plain of Rio Grande do Sul, southern Brazil. Variations in the biomass of emergent plants and their distribution were related to sediment features and salinity. Macrophytes density and stem height showed a close relation to the aboveground biomass during the high water level. A significant inverse correlation was found between S. californicus height and interstitial salinity of the underlying sediments S. olneyi height was not correlated with interstitial salinity but with organic matter and water content of the sediments.
Location: 241
Literature cited 1: None
Literature cited 2: None
ID: 55396
Title: Native freshwater vegetation communities in the Mekong Delta
Author: Le Cong Kiet
Editor: P S Ramakrishnan and Brij Gopal
Year: 1994
Publisher: International Scientific Publications, Vol 20, No 1-2, 1994
Source: Centre for Ecological Sciences
Reference: None
Subject: International Journal of Ecology and Environmental Sciences
Keywords: Flooding, acid sulphate soils, Riverbanks, Marshes, plant community, ecological amplitude, Melaleuca
Abstract: Multiple land uses, particularly for the development of intendsive agricultural and fisheries, in the Mekong Delta have greatly affected the natural vegetation of the region which was once dominated by Melaleuca forest. Only scattered vestiges of the native freshwater vegetation now remain along the riverbanks and in some remote sectors in both the annually-inundated plain of Reeds and the Quadrangle of Long Xuyen. The distribution, and floristic composition of the plant communities is determined mainly by the depth and duration of flooding, water flow, and acid sulphate soils. Ecological amplitudes of dominant plant species related to salinity and pH can be used as indicators of environmental conditions. Some tentative observations are made on the community dynamics on the basis of its distribution pattern.
Location: 241
Literature cited 1: None
Literature cited 2: None
ID: 55395
Title: Cyanobacterial mats: A possible nitrogen source for arid-coast mangroves
Author: E I Paling and A J McComb
Editor: P S Ramakrishnan and Brij Gopal
Year: 1994
Publisher: International Scientific Publications, Vol 20, No 1-2, 1994
Source: Centre for Ecological Sciences
Reference: None
Subject: International Journal of Ecology and Environmental Sciences
Keywords: Algal mats, nitrogen fixation, nitrogen export, Avicennia marina, Phormidium, Microcoleus chthonoplastes
Abstract: A combination of large tidal range, high temperatures and low rainfall in the north west of Western Australia markedly restricts mangrove development to a narrow belt which fringes the shores and short tidal creeks. Nonheterocystous cyanobacterial mats cover a large proportion of the extensive saline flats behind the most landward mangroves (Avicennia marina). These mats are predominantly composed of the species Microcoleus chthonoplastes and Phormidium sp. and show significant nitrogen fixation (acetylene reduction) rates both in culture and in situ. Estimates from pervious studies show that from 1 to 128 kg of nitrogen could be fixed per hectare annually. The nitrogen contained within these mats may be leached by tidal inundation and by the sporadic, but intense, rainfall. Leaching rates were 3-7 mg Nm-2h-1 in seawater and in situ enclosure experiments estimated that 68 kg N ha-1 could be exported annually to the adjacent mangrove systems.
Location: 241
Literature cited 1: None
Literature cited 2: None
ID: 55394
Title: Isotopic composition of majors carbon reservoirs in the Amazon floodplain
Author: Luiz A Martinelli, Renaldo L Victoria, Bruce R Forsberg and Jeffrey E Richey
Editor: P S Ramakrishnan and Brij Gopal
Year: 1994
Publisher: International Scientific Publications, Vol 20, No 1-2, 1994
Source: Centre for Ecological Sciences
Reference: None
Subject: International Journal of Ecology and Environmental Sciences
Keywords: Phyto plankton, periphyton, varzea, floodplain sediments, particulate organic carbon, atmoshperic CO2
Abstract: In this paper we examine the carbon isotopic composition of major carbon reservoirs in the Assam floodplain. Loss of 13C depleted CO2 from the Amazon river decreased the ?13 C of the atmospheric CO2 during the night. The results for different vegetation types were highly variable. In the terrestrial system the lightest value was found in samples of leaves from the forest understory (-32.9 %), followed by leaves from the canopy (-32.1%), litter (-30.5%), boles (-29.8%), and finally by leaves from open areas (-29.6%). The heaviest values were foudn for C4 grasses (-13%). In the aquatic environment phytoplankton was the lightest (-34.1%), followed by floating herbaceous plants (-28.9%) and periphyton (-28.3%). The ?13 C of fine and coarse riverine particulate organic carbon were distinct, the first was significantly heavier. For the tributaries, the fine fraction of white and black-water rivers were distinctly differemt. The ?13 C of the Amazon (white-water) fine fraction was -27%, while the Negro river (black-water) was -28.2% and Jutai (black-water) was even lighter with -31%. The carbon isotopic composition of floodplain sediments was a function of its carbon sources: riverine particulate organic carbon and overlying vegetation. Sediment samples from forested areas showed lighter ?13 C (-13.3%) than samples collected under grass mats (-25.3%) or vegetation free areas (-27.4%). The lightest value for sediments was found in samples from the bottom of floodplain lakes (-29.7%).
Location: 241
Literature cited 1: None
Literature cited 2: None
ID: 55393
Title: Influence of summer storms on the solution geochemistry in a coastal plain hydrosequence
Author: Jeffrey M Novak
Editor: P S Ramakrishnan and Brij Gopal
Year: 1994
Publisher: International Scientific Publications, Vol 20, No 1-2, 1994
Source: Centre for Ecological Sciences
Reference: None
Subject: International Journal of Ecology and Environmental Sciences
Keywords: Throughfall, wetland soil, stream water, floodplain, land-water interaction
Abstract: An understanding of factors which influence wetland soil solution chemistry is important for soil solutions are known to influence some chemical properties of surface waters. The influence of summer storms on the solution geochemistry in a South Carolina riverine wetland soil was evaluated by comparing pore water collected 24 hr after five summer strom events with pore water acquired during five nonstorm periods. Pore water was collected by tension lysimeters buried at 15 to 152 cm in two locations along a hydrologica gradient. Samples of rain, throughfall and stream water were also collected. Overall, summer storms had no significant influence on the concentrations of anions, cations, DOC, pH and electrical conductivity (EC) in soil pore water at both floodplain locations. There was a tendency for higher concentrations of dissolved NO3-N, NH4-N and PO4-P in soil pore water after periods of high rainfall. In many situations, water chemistry was influenced by the degree of soil saturation. The seasonally wet soil of the floodplain had statistically higher mean concentrations of Ca, Fe, Na, Cl and EC values relative to the drier soil. Throughfall had a significant influence on the concentrations of K and DOC, whereas soil had a significant effect on some anions, cations, pH, and EC. These results suggest that pore water chemistry is primarily a function of the degree of soil saturation during nonstorm periods. Storms had little influence on soil pore water or stream water chemistry.
Location: 241
Literature cited 1: None
Literature cited 2: None
ID: 55392
Title: Water chemistry of two hydric soils of Southern Louisiana
Author: A A Szogi and W H Hudnall
Editor: P S Ramakrishnan and Brij Gopal
Year: 1994
Publisher: International Scientific Publications, Vol 20, No 1-2, 1994
Source: Centre for Ecological Sciences
Reference: None
Subject: International Journal of Ecology and Environmental Sciences
Keywords: Wetland, aquic, groundwater, Natraqualfs, sodic
Abstract: Chemical composition of the shallow groundwater of two hydric soils in southern Louisiana was monitored for one year. Two sites were instrumented with nested wells (0.25, 0.50, 0.68 or 0.78, 1.00 and 2.00 m depth). One of the sites is located in Calcasieu Parish on a Brimstone soil (fine-silty, mixed, thermic Typic Natraqualfs) and the other one at Livingston Parish on a Verdun soil (fine-silty, mixed, thermic Glossic Natraqualfs). Electrical conductivity (EC), pH and cation and anion composition were determined for every water sample. Variations in the composition, EC and pH were attributed to differences in soil and parent materials, soil physical properties and groundwater flow. Brimstone soil is a typical hydric soil with a perched water table. The water is supplied by rainfall and lateral movement from the adjacent higher landscape with addition of NO3 and leaching of Na and Cl. Na and Cl accumulate at short distances in depressional areas. Verdun soil has a morphology that would indicate that leaching of Na is a predominant process. However, presently the soil is undergoing secondary salinization produced by discharge from a permanent groundwater table. The discharging groundwater is brackish, of probable marine origin as indicated by the strong relationships Cl-Na (r2 = 0.75, P>0.01) and Cl - Na + Mg (r2 = 0.89, P > 0.01)
Location: 241
Literature cited 1: None
Literature cited 2: None
ID: 55391
Title: Transformation of tropical wetland habitats for forage and fuel production in India
Author: B D Patil and P S Pathak
Editor: Prof R Misra
Year: 1981
Publisher: International Scientific Publications, Vol 7, 1981
Source: Centre for Ecological Sciences
Reference: None
Subject: International Journal of Ecology and Environmental Sciences
Keywords: Wetlands, rural population
Abstract: Wetlands occur over a range from free-flowing to semi-dry habitats adn are a mosaic of micro- and macro-habitats. There are large areas of wetlands in India; perhaps one-third of the country could be classed as wetland. Consequently, these areas are highly productive and often difficult to manipulate for economically productive uses. The careless use of Indian wetlands has resulted in serious imbalances between soil and vegetation. This paper enumerates these problems adn analyses the potential solutions for using these wetlands as a forage and fuelwood soruces for the rural population.
Location: 241
Literature cited 1: None
Literature cited 2: None
ID: 55390
Title: Notes on the ecological and socio-economic importance of wetlands of Manipur, N.E. India
Author: P S Yadava
Editor: Prof R Misra
Year: 1981
Publisher: International Scientific Publications, Vol 7, 1981
Source: Centre for Ecological Sciences
Reference: None
Subject: International Journal of Ecology and Environmental Sciences
Keywords: wetlands, conservation
Abstract: In Manipur (N.E.India), lake Loktak and adjacent swamps dominated by Phragmites karka are important habitat for the brown antler deer (Cervus elde elde) which is an endangered species. The extensive clearing, burning and other human activities have destroyed the wetlands. The paper stresses the need for detailed studies and conservation in the area.
Location: 241
Literature cited 1: None
Literature cited 2: None
ID: 55389
Title: Benthic fauna in a wetland ecosystem (Ghana Bird Sanctuary, Bharatpur) subjected to drought stress
Author: C L Mahajan, S D Sharma, S P Sharma and N K Arora
Editor: Prof R Misra
Year: 1981
Publisher: International Scientific Publications, Vol 7, 1981
Source: Centre for Ecological Sciences
Reference: None
Subject: International Journal of Ecology and Environmental Sciences
Keywords: macrobenthos
Abstract: The species composition, population size and biomass of major macrobenthic invertebrate groups (Oligochaeta, Insecta and Mollusca) in Ghana Bird Sanctuary, Bharatpur, have been studied during 1978 adn 1979. The year 1979 was a drought year and thus, provided an insight into the changes in macrobenthos of the area due to drought.
Location: 241
Literature cited 1: None
Literature cited 2: None
ID: 55388
Title: Changes in zooplankton populations in a wetland ecosystem due to drought
Author: C L Mahajan, S P Sharma, S D Sharma and N K Arora
Editor: Prof R Misra
Year: 1981
Publisher: International Scientific Publications, Vol 7, 1981
Source: Centre for Ecological Sciences
Reference: None
Subject: International Journal of Ecology and Environmental Sciences
Keywords: Population densities, biomass, zooplanktons, drought
Abstract: The paper reports changes in population densities and biomass of various groups of zooplankton during 1978-79 in the Ghana Bird Sanctuary, Bharatpur (Rajasthan). Drought conditions during 1979 resulted in decrease of most zooplankton (cladocera, insect larvae, turbellarians) but the rotifers and copepods increased. A correspondence with steep rise in chloride content adn alkalinity of water indicates greater tolerance of these zooplankton to the stress.
Location: 241
Literature cited 1: None
Literature cited 2: None