Is faunal diversity on Maltese sandy beaches related to intensity of human use?

Sandy beaches are rare in the Maltese Islands where only some 2.4% of the ca 271km coastline is sedimentary; yet such beaches are much sought after for their amenity value by tourists and locals alike. Carrying capacity studies conducted by the Malta tourism authorities have shown that most beaches are under very heavy use while a study by Deidun et al. (2003) has indicated that the fauna of Maltese sandy beaches tends to be impoverished compared to other Mediterranean beaches and has hinted that this may be a result of lack of recruitment due to the relative isolation of these beaches. Therefore human use of Maltese sandy beaches may potentially be a key factor affecting faunal diversity of these beaches. We explored this hypothesis by sampling the faunal assemblages of four Maltese beaches (Gnejna and White Tower Bay on Malta, and Xatt l-Ahmar and Ramla l-Hamra on Gozo) using pitfall traps set up in the wet and dry zones of each beach during the summer, when human use is expected to be highest. Human use of these beaches was assessed by estimating human occupancy of the beaches from standardised photographs. Beach occupancy values of 2400, 5700, 6700, and 12300 persons per square km were estimated for Ramla, White Tower Bay, Xatt l-Ahmar and Gnejna, respectively, establishing a gradient of anthropogenic impact with Gnejna as the most impacted beach and Ramla the least. Three components of faunal diversity were considered: population size (number of individuals), species richness, and taxonomic composition. Faunal population size ranged from 7 individuals/trap/hour for Xatt l-Ahmar to 199 individuals/trap/hour for Ramla in the wet zone, and from 22 individuals/trap/hour for White Tower Bay to 87.33 individuals/trap/hour for Gnejna in the dry zone. The species richness ranged from 7 species (Xatt l-Ahmar) to 17 species (White Tower Bay). Between them, Amphipoda, Isopoda, Coleoptera Dermaptera and Hymenoptera accounted for the bulk of both species and individuals collected. There were no statistically significant correlations between population size, species richness and taxonomic composition. The species collected from the four beaches was categorized into psammophiles, coastal species (occurring in coastal habitats but not restricted to sandy beaches) and euryoecious (ubiquitous) species. Ramla exhibited the highest proportion of psammophiles (98.4% of all species collected at Ramla) and the lowest proportion of ubiquitous ones (1.5% of all species), whilst for Xatt L-Ahmar the equivalent figures were 31.8% and 61.8% for ubiquitous and psammophilic species respectively From the present study it results that there is no trend between any of the three components of faunal diversity analysed and the degree of human occupancy of the beaches, and the only tangible human impact was related to faunal habitat–use specificity. This suggests that human use of the beaches has no direct impact on the faunal assemblages of the mediolittoral and supralittoral zone of the beaches studied but that high levels of human disturbance result in generalists displacing specialist psammophilic species. In spite of these results, intense human use of Maltese sandy beaches is of conservation concern since previous work has indicated a high degree of ‘compartmentalisation’ with different beaches harbouring distinct faunal assemblages either due to natural inter-beach barriers to dispersal, or due to unique environmental conditions present on the different beaches, including the nature and intensity of anthropogenic pressures. In addition, the present study addresses only the direct effect of trampling by beach visitors; indirect negative impacts, such as those of beach cleaning, have been well documented in other studies.peer-reviewe

Water Quality and Water Rights in Colorado

44 p. ; 28 cmhttps://scholar.law.colorado.edu/books_reports_studies/1105/thumbnail.jp

Integrating Tributary Groundwater Development into the Prior Appropriation System: The South Platte Experience

46 p. : ill., maps ; 28 cmhttps://scholar.law.colorado.edu/books_reports_studies/1111/thumbnail.jp

Water Quality and Water Rights in Colorado

44 p. ; 28 cmhttps://scholar.law.colorado.edu/books_reports_studies/1105/thumbnail.jp

Integrating Tributary Groundwater Development into the Prior Appropriation System: The South Platte Experience

46 p. : ill., maps ; 28 cmhttps://scholar.law.colorado.edu/books_reports_studies/1111/thumbnail.jp

Agricultural to Urban Water Transfers in Colorado: An Assessment of the Issues and Options

iii, 82 p. ; 28 cmhttps://scholar.law.colorado.edu/books_reports_studies/1063/thumbnail.jp

The Endangered Species Act and Water Development Within the South Platte Basin

v, 122, 19 p. : maps ; 28 cmhttps://scholar.law.colorado.edu/books_reports_studies/1125/thumbnail.jp

Prediction of Lake-level Changes for Various Climatic Scenarios using a Water-balance Model, Waubay Lakes Chain, Northeastern South Dakota (Task 2)

From the Executive Summary: The closed basins area, which includes parts of Day, Marshall, Roberts, Codington, and Clark Counties, in northeastern South Dakota, was declared a Federal Disaster Area in 1990. Under the sponsorship of Region 8 of the Federal Emergency management Agency, an interagency study team was formed to conduct an interdisciplinary scientific investigation of the flooding n the closed basins area. Agencies represented include Federal Emergency Management Agency, U.S. Geological Survey, U.S. Army Corp of Engineers, South Dakota State University, Natural Resources Conservation Service, South Dakota Department of Environment and Natural Resources, and the South Dakota Geological Survey. Task 2 focuses on predictions of lake-level and corresponding surface-area, and water-volume changes of the 10 major lakes in the Waubay Lakes Chain closed basin using the water-balance model, developed by the U.S. Geological Survey, as part of task 4. Northeastern South Dakota is situated in a unique geographic setting, the result of glaciation which ended about 10,000 years ago. The area is dominated by the Coteau des Prairies a flatiron shaped topographic high, rising up to 400 feet above the James River Basin to the west, and 900 feet above the Minnesota River - Red River Lowland to the east. Drainage on the Coteau is poorly developed, resulting in internal drainage only, producing areas called closed basins. The closed basins area consists of several internally drained basins that are not connected to each other, or to either the James River or Big Sioux drainages, under normal climatic conditons. The closed basins area contains thousands of temporary and permanent ponds (potholes and lakes. Streams may connect two or three of the potholes, but typically flow only during periods of high water levels in the ponds. All of the lakes and ponds in the closed basins area have experienced water level increases and corresponding surface-water inundation, but the greatest flooding has been within the Waubay Lakes Chain closed basin. Beginning in 1983, a period of above normal precipitation began whose duration and magnitude has not been observed previously in the modem instrumental record. The precipitation event, coupled with be ow normal evaporation, has resulted in a water surplus within the closed basins area. This et increase in available water has resulted in flooding which has not been observed in the moden record. During the 1990\u27 s, many potholes have filled to capacity and are either spilling into other ponds or lakes, or have coalesced into larger surface water bodies. (See more in text

A method for assessing the performance of genetic algorithm optimization for water distribution design

The paper proposes a new methodology for assessing the effectiveness of GA parameters in consistently finding similar low cost solutions over a broad range of different starting random number seeds. The method involves testing the parameters of probabilities of crossover (for various crossover types) and probabilities of bitwise mutation with 1000 different random number seeds. In addition, this methodology allows different varieties of GA to be compared so that the methodology with the best performance can be determined. The proposed methodology has been verified for its effectiveness on the previously published benchmark network New York Tunnels Problem.Feifei Zheng, Angus R. Simpson and Aaron C. Zecchi

Issues and Trends in Western Water Marketing

12 p. ; 28 cmhttps://scholar.law.colorado.edu/books_reports_studies/1116/thumbnail.jp