An economic analysis of woodfuel management in the Sahel : the case of Chad

The woodlands in some parts of the Sahel are effectively an open-access resource. Under open access, fuelwood cutters have no incentive to allow for benefits that might accrue if the wooded area were managed rather than mined. Those benefits include sustainable streams of fuelwood, fruits, and other tree products, browse for cattle, and ecological services such as nitrogen fixation and erosion prevention. To remedy this problem, some Sahelian areas have moved to give communities effective control of local woodland resources. To make it easier to analyze the economic cost of such supply-side interventions, the authors present an economic framework and computational method for assessing policy impacts on the cost of woodfuel supplies, and the spatial distribution of biomass, in a particular Sahelian woodland setting. They use spatial data on standing stock and on the costs of transport to market to model a supply curve of fuel to a fuel-consuming location. given an exogenously specified demand, the model simulates, period by period, the extraction, regeneration, and transport of wood fuels. It also permits easy calculation of the dynamic cost of woodfuel depletion. They apply the model to evaluate the benefits and ecological impacts of various scenarios for woodland management around the city of N'Djamena in Chad.Markets and Market Access,Economic Theory&Research,Environmental Economics&Policies,Labor Policies,Agricultural Knowledge&Information Systems,Economic Theory&Research,Environmental Economics&Policies,Access to Markets,Markets and Market Access,Geographical Information Systems

How the location of roads and protected areas affects deforestation in North Thailand

Using plot-level data, the authors estimate a bi-variate probit model to explain land clearing, and the siting of protected areas in North Thailand in 1986. Their model suggests that protected areas (national parks, together with wildlife sanctuaries) did not reduce the likelihood of forest clearing, but wildlife sanctuaries may have reduced the probability of deforestation. Road building, by reducing the impedance-weighted distance to market, has promoted clearing, especially near the forest fringe. The authors stimulate the impact of further road building to show where road building is likely to have the greatest impact on forest clearing, and where it is likely to threaten protected areas.Wetlands,Climate Change,Earth Sciences&GIS,Environmental Economics&Policies,Water Conservation,Climate Change,Wetlands,Earth Sciences&GIS,Environmental Economics&Policies,Forestry

Roads, population pressures, and deforestation in Thailand, 1976-89

Tropical deforestation is considered one of the major environmental disasters of the 20th century, although there have been few careful studies of its causes. This paper examines the causes of deforestation in Thailand between 1976 and 1989, a period when the country lost 28% of its forest cover. This paper takes the perspective that, in the long run, the determinants of deforestation are the determinants of land use change. While logging and fuelwood gathering may remove forest cover, regrowth will occur, at least in moist tropical forests. For an area to remain deforested, it must be profitable to convert the land to another use, and this use is usually agricultural. In Thailand, for example, agricultural land increased between 1961 and 1988; during the same period, forest land decreased. This paper focuses on what, in equilibrium, determines the amount of land cleared for agriculture. The authors emphasize the quantitative impact of two forces--roads and population pressures--that increase the profitability of converting forest land to agriculture. As aerial maps show, development follows road networks. The magnitude of the impact of roads on commercial and subsistence agriculture depends on soil quality along the road. In this case the Thailand government undertook a road-building program in the Northeast section in the 1970's to encourage settlement of that region as a bulwark against Communist encroachment from Laos. Road building very likely spurred deforestation in the Northeast during the 1970's and 1980's, although the magnitude of its impact is not known. Thailand also experienced rapid population growth during this same period, which may have contributed to deforestation in two ways: the growing population demanding more food, increased the demand for agricultural land; and more importantly, in rural areas where other economic opportunities are limited and squatters are permitted on forest lands, a growing population increased the demand for land for subsistence agriculture. The authors conclude that population pressures play less of a role in deforestation than was found in earlier studies on Thailand. Affecting the amount of deforestation are other factors, such as the profitability of converting the land to another use, natural protection for forests like poor soil and steep slopes, and agricultural price variations.Environmental Economics&Policies,Climate Change,Agricultural Knowledge&Information Systems,Land Use and Policies,Agribusiness,Agricultural Trade,Environmental Economics&Policies,Forestry,Agricultural Knowledge&Information Systems,Climate Change

The Gammaridean and Caprellid Amphipoda of Southern Africa

It is the intention of this thesis to bring together the existing scattered data concerning the Amphipoda of southern Africa, to add records from unidentified collections and to present the whole in a form that will provide a firm basis for future work in this field. The collections examine d are principally those of the University of Cape Town, the South African Museum and the National Institute for Water Research. These collections are together much larger than any previously reported from southern Africa (in excess of 90 000 specimens from several thousand stations). Findings are presented in a series of five regional papers. Each paper includes brief descriptions of principal collecting areas and their faunas and an analysis of species collected. Station data, references and distributions are provided for all species, while a short diagnosis is given with the first reference to each species. A total of 299 gammaridean and caprellid species is recognised. One family (Temnophliidae), four genera (Chaka, Cunicus, Dikwa, Janice) and 39 species are described as new to science; while 21 others are recorded from southern Africa for the first time. Nine existing species are relegated as synonyms. Following the five regional taxonomic papers, a synoptic guide to the benthic amphipods of the region is provided. This is intended to provide the non-specialist with a means of identifying his own material. A brief guide to methods of collection, storage and examination is provided and is followed by comprehensive fully illustrated keys to the families, genera and species of gammaridean and caprellid Amphipoda recorded from Africa south of 20 degree S, 0-1000m. The figures cover virtually all species, including many never before illustrated and will hopefully reduce the need for exhaustive knowledge of morphological nomenclature, or of extensive reference facilities, before identifications can be made. An appendix provides reference to more detailed descriptions of each species, gives their distributions world-wide and within southern Africa, and lists common synonyms. A concluding chapter discusses modes of dispersal of amphipods and possible origins of the southern African fauna. The region can apparently be divided into tropical, subtropical and temperate provinces, the first two dominantly populated by species of tropical origins and the third rich in endemic forms. This pattern is paralleled in other groups such as the polychaeta. It is concluded that although southern Africa is rich in endemic species and genera it is not a centre for the evolution of major taxa but rather an evolutionary outpost where immigrant forms have evolved under reduced pressure

Shark and skate egg-cases cast up on two South African beaches and their rates of hatching success, or causes of death

Collections of chondrichthyan egg-cases cast ashore at two sites along the South African coastline were identified and examined for cause of mortality. A total of 574 egg-cases collected from False Bay could be attributed to five species of scyliorhinid shark. two skates and the elephantfish or chimaera, while the 538 egg-cases collected from Port Alfred belonged to four scyliorhinid sharks and two skate species. At both sites eggs of shysharks of the genus Haploblepharus made up more than 70% of the samples, followed by skates (5% in False Bay and 19% in Port Alfred) and then catsharks of the genus Porodenna (1 and 7% respectively). Haploblepharus egg-cases generally displayed relatively high rates of hatching success of over 60% and predation rates of 18-30%. Haploblepharus fuscus was the exception with a low hatching success of 37% and a predation rate of 40%. Porodenna egg-cases suffered predation losses of 43%. and had a hatching success of 47%. Skate egg-cases displayed non-predator induced egg mortalities of up to 35%, but predation rates of less than 14%. Hatching success was moderate at 57%. The holes found in egg-cases could be categorised into five types, of which four were clearly predator boreholes. The most abundant of these was shown to be caused by whelks of the genus Bumupena.S Afr. J. Zool 1997, 32(4

Falling in Acute Mental Health Settings for Older People : Who falls, where, when and why?

Copyright: © 2014 Dickinson A et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.Falls, slips and trips are a major patient safety concern in hospital settings accounting for 26 per cent of all reported patient safety incidents in England. Mental health conditions and their treatments add further to fall risk but we have little information regarding who falls, where and when within mental health settings. Methods: This paper presents an overview of the pattern of falls by older patients within an in-patient mental health setting in the South of England using routine records completed by staff when a fall occurs. 920 fall reports over three years were analysed, and 7 focus groups were undertaken with ward staff to explore how staff understood falls and their experiences of using the falls reporting system. Results: In terms of diagnosis 40% of fallers had a primary functional diagnosis, 46% an organic mental health diagnosis (14% non-specific diagnosis), average age was 81.7 years (range 59 to 99 years; SD 8.3) and 57% were female. Approximately one quarter, 27%, of falls were observed by staff. Falls were not evenly distributed across either day of week or time of day, with peak times for falls on Tuesday and Saturday and morning (7-8 and 9-10am) and subsidiary peaks between noon and 1pm and early evening (5-6pm). Almost half of falls occurred in private spaces in the ward such as bedrooms, and 42% in public spaces such as sitting rooms. However 60% of falls in public spaces were unseen. Reporting in these settings was problematic for staff and patients were sometimes described as placing themselves on the floor as a consequence of their mental health condition. The average time to first fall was 5 weeks. Conclusions: Routine mapping of falls could be undertaken at ward and organization level and contribute to better understanding of the local factors contributing to falls. Exploring incident report data in focus groups with staff helped us and them to interpret the data and to understand some of the decision making staff engage in everyday when reporting falls.Peer reviewedFinal Published versio

Sources of nutrition in intertidal sea anemones from the south-western Cape, South Africa

Respiration rates of seven species of intertidal sea anemones from the south-western Cape, South Africa were measured with and without illumination to determine whether zooxanthellae contributed to their nutritional needs. Light had no significant effect on oxygen exchange in any of the species, suggesting that all are azooxanthellate. Diets of anemones from two sites, Wooley’s Pool in False Bay and Blouberg on the Atlantic coast some 20 km north of Cape Town, were examined by gut content analysis. Seven species occurred at Wooley’s Pool, but only one (Bunodactis reynaudi) at Blouberg. At Wooley’s Pool 39.4% of anemones contained food, while at Blouberg only 7.4% did so. A wide spectrum of prey taxa were consumed by the various anemone species, although considerable dietary overlap occurred. Pelecypods, gastropods and isopods were ingested by all the species examined. Pelecypods dominated the diet of B. reynaudi at Blouberg (91% occurrence), but were recorded in only 42% of the same species at Wooley’s Pool. The frequency of occurrence of pelecypods in the guts of the other species ranged from 9% (Anthothoe stimpsoni) to 28% (Actinia equina). Gastropods were the main prey items eaten by Anthopleura michaelseni (67% occurrence), Pseudactinia flagellifera (43%) and Pseudactinia varia (42%), while isopods were the most frequently occurring constituent in the diets of A. stimpsoni (62%) and Bunodosoma capensis (16%). A. equina was the only species for which insects were a regular part of the diet (26% occurrence). Platyhelminths were found only in the guts of B. capensis (11%); holothurians only in B. reynaudi at Wooley’s Pool (2%), and crinoids only in P. flagellifera (2%). Large quantities of algal material and indigestible debris were also ingested, indicating that sea anemones are non-selective feeders. Cluster analysis and multi-dimensional scaling techniques revealed four distinct feeding groups among the anemone assemblages. These are characterized as microphagous (A. stimpsoni), generalist (S. capensis and A. equina), macrophagous (S. reynaudi at Wooley’s Pool, A. michaelseni, P. flagellifera and P. varia) and specialist bivalve- feeder (B. reynaudi at Blouberg)

Korsaranthus natalensis (Carlgren, 1938) nov. comb. (Cnidaria: Actiniaria) a mobile sea anemone attacking octocorals

In-situ observations and photographs of an unusual and spectacular red and white striped, mobile anemone, which appears to feed on gorgonians on sublittoral habitats on the south and east coasts of South Africa, prompted a closer examination of two preserved specimens. The specimens are identical with Condylactis natalensis  Carlgren, 1938, which was described from a single preserved specimen and has not since been reported. The redescription of the species indicates that a new genus, Korsaranthus, is required to accommodate it within the family Actiniidae. Most significant characteristics of K. natalensis are the lack of p-mastigo- phores in its cnidome and the folded, distal-most part of its actinopharynx, features that compare with members of order Ptychodactiaria, which are predators of octocorals, too

Digestion rates of prey eaten by intertidal sea anemones from the south-western Cape, South Africa

Digestion rates were determined for natural prey items offered to each of seven species of sea anemones found at Wooley's Pool in False Say and to the single species (Bunodactis reynaudl) recorded at Siouberg on the Atlantic coast of the south-western Cape, South Africa.This was done by examining prey items removed from the coelenterons at regular intervals after feeding and assessing their degree of digestion according to a predetermined scale. There was considerable variation in the gut retention times between different anemone species offered the same prey types, with Actinia equina consistently showing the shortest gut retention times (12 h for amphipods, 15 h for pelecypods and 23 h for isopods). Of the various prey categories tested, amphipods tended to be the most rapidly digested group, while molluscs and echinoderms usually remained in the coelenteron the longest. Mean gut retention times in B. reynaudi, the only species found both in False Bay (1 TC) and on the cold west coast (12'C) were markedly longer (72 vs 60 hand 43 vs 30 h for pelecypods and gastropods respectively) at the lower temperature.S. Afr. J. Zool. 1997,32(4