The hydrodynamic response of a semi-arid headwater wetland to technical rehabilitation interventions

Loss of wetland extent continues to be documented as a significant problem and this is true for the headwaters of the Sand River system in the north-east of South Africa. Here wetlands are undergoing severe down-cutting by erosion gullies (dongas) leading to desiccation of the system and loss of viable substrate that is used for subsistence agriculture. The Manalana sub-catchment was the focus of an integrated wetland rehabilitation programme between 2004-2009, a major focus of which was the stabilisation of such erosion gullies by large retaining structures. This paper presents findings of a hydrological monitoring study of the shallow groundwaters to determine the wetland’s hydrodynamic behaviour and the extent to which this had degraded as a result of erosion. Furthermore, whether technical rehabilitation could ameliorate any degradation in the wetland’s hydrological condition was also assessed. The findings show that the wetland groundwater hydrology is strongly controlled by the distribution of clays within it, facilitating distinct hydrological micro-regions within the wetland spatially and vertically. Based on these findings it is revealed that the loss of these clays impacts severely on the system’s hydrology. The installation of an impermeable buttress weir was able to restore these hydrodynamics as observed through the reversal of the hydraulic gradients between groundwater observation stations, but the precise placement of the structure was shown to be crucial for this effect. This finding demonstrated the requirement of informed, or wise, technical rehabilitation principles based on hydro-geomorphic understanding of the system. A downstream pervious gabion dam was also monitored for its effect on restoring the wetland’s hydrology, but observed responses showed little change, and, in fact, the wetlands hydrology here remained intact, attributed to the presence of a clay plug that was saved from erosion by the placement of this structure.Keywords: wetlands, rehabilitation, phreatic surface, piezometer, aquitar

Phenotypic Evidence of Emerging Ivermectin Resistance in Onchocerca volvulus

Onchocerciasis, commonly known as river blindness, is caused by the filarial nematode Onchocerca volvulus and is transmitted by a blackfly vector. Over 37 million people are thought to be infected, with over 90 million at risk. Infection predominantly occurs in sub-Saharan Africa. Foci also exist in the Arabian Peninsula and Central and South America. Ivermectin, the sole pharmaceutical available for mass chemotherapy, has been used on a community basis for annual or semi-annual treatment since 1987. Multiple treatments with ivermectin kill the microfilariae that are responsible for the pathology of onchocerciasis. More importantly, ivermectin suppresses the reproductive activity of the adult female worms, thus delaying or preventing the repopulation of the skin with new microfilariae and thereby reducing transmission. This study extends earlier reports of sub-optimal responses to ivermectin by examining repopulation levels of microfilaria one year after treatment, worm burdens per nodule, the age structure of adult female worms recovered from nodules, and the reproductive status of adult female worms 90 days after ivermectin treatment. In some communities which have shown a pattern of sub-optimal response to treatment, the data is consistent with an emergence of ivermectin non response or resistance manifested by a loss of the effect of ivermectin on the suppression of parasite reproduction

Integrative Taxonomy for Continental-Scale Terrestrial Insect Observations

Although 21st century ecology uses unprecedented technology at the largest spatio-temporal scales in history, the data remain reliant on sound taxonomic practices that derive from 18th century science. The importance of accurate species identifications has been assessed repeatedly and in instances where inappropriate assignments have been made there have been costly consequences. The National Ecological Observatory Network (NEON) will use a standardized system based upon an integrative taxonomic foundation to conduct observations of the focal terrestrial insect taxa, ground beetles and mosquitoes, at the continental scale for a 30 year monitoring program. The use of molecular data for continental-scale, multi-decadal research conducted by a geographically widely distributed set of researchers has not been evaluated until this point. The current paper addresses the development of a reference library for verifying species identifications at NEON and the key ways in which this resource will enhance a variety of user communities

Bacillus thuringiensis Cry5B Protein Is Highly Efficacious as a Single-Dose Therapy against an Intestinal Roundworm Infection in Mice

Intestinal parasitic nematode diseases infect over one billion people and cause significant disease burden in children (growth and cognitive stunting, malnutrition), in pregnant women, and via their dampening of the immune system in infected individuals. In over thirty years, no new classes of anti-roundworm drugs (anthelmintics) for treating humans have been developed. Because of limitations of the current drugs and the threat of parasite resistance, new anthelmintics are needed. The soil bacterium Bacillus thuringiensis (Bt) produces crystal (Cry) proteins that specifically target and kill insects and nematodes and is used around the world as a safe insecticide. Here we test the effects of the Bt Cry protein Cry5B on a chronic, natural intestinal roundworm infection in mice, namely the helminth parasite Heligmosomoides bakeri. We find that a single dose of Cry5B can eliminate 70% of the parasites and can almost completely block the ability of the parasites to produce progeny. Comparisons of Cry5B's efficacy with known anthelmintics suggest its activity is as good as or perhaps even better than those currently used. Furthermore, this protein is rapidly digested by simulated stomach juices, suggesting that protecting it from these juices would reveal a superior anthelmintic

Urban Biodiversity and Landscape Ecology: Patterns, Processes and Planning

Effective planning for biodiversity in cities and towns is increasingly important as urban areas and their human populations grow, both to achieve conservation goals and because ecological communities support services on which humans depend. Landscape ecology provides important frameworks for understanding and conserving urban biodiversity both within cities and considering whole cities in their regional context, and has played an important role in the development of a substantial and expanding body of knowledge about urban landscapes and communities. Characteristics of the whole city including size, overall amount of green space, age and regional context are important considerations for understanding and planning for biotic assemblages at the scale of entire cities, but have received relatively little research attention. Studies of biodiversity within cities are more abundant and show that longstanding principles regarding how patch size, configuration and composition influence biodiversity apply to urban areas as they do in other habitats. However, the fine spatial scales at which urban areas are fragmented and the altered temporal dynamics compared to non-urban areas indicate a need to apply hierarchical multi-scalar landscape ecology models to urban environments. Transferring results from landscape-scale urban biodiversity research into planning remains challenging, not least because of the requirements for urban green space to provide multiple functions. An increasing array of tools is available to meet this challenge and increasingly requires ecologists to work with planners to address biodiversity challenges. Biodiversity conservation and enhancement is just one strand in urban planning, but is increasingly important in a rapidly urbanising world

Iron Behaving Badly: Inappropriate Iron Chelation as a Major Contributor to the Aetiology of Vascular and Other Progressive Inflammatory and Degenerative Diseases

The production of peroxide and superoxide is an inevitable consequence of aerobic metabolism, and while these particular "reactive oxygen species" (ROSs) can exhibit a number of biological effects, they are not of themselves excessively reactive and thus they are not especially damaging at physiological concentrations. However, their reactions with poorly liganded iron species can lead to the catalytic production of the very reactive and dangerous hydroxyl radical, which is exceptionally damaging, and a major cause of chronic inflammation. We review the considerable and wide-ranging evidence for the involvement of this combination of (su)peroxide and poorly liganded iron in a large number of physiological and indeed pathological processes and inflammatory disorders, especially those involving the progressive degradation of cellular and organismal performance. These diseases share a great many similarities and thus might be considered to have a common cause (i.e. iron-catalysed free radical and especially hydroxyl radical generation). The studies reviewed include those focused on a series of cardiovascular, metabolic and neurological diseases, where iron can be found at the sites of plaques and lesions, as well as studies showing the significance of iron to aging and longevity. The effective chelation of iron by natural or synthetic ligands is thus of major physiological (and potentially therapeutic) importance. As systems properties, we need to recognise that physiological observables have multiple molecular causes, and studying them in isolation leads to inconsistent patterns of apparent causality when it is the simultaneous combination of multiple factors that is responsible. This explains, for instance, the decidedly mixed effects of antioxidants that have been observed, etc...Comment: 159 pages, including 9 Figs and 2184 reference

Assessment of the long-term response to rehabilitation of two wetlands in KwaZulu-Natal, South Africa:

Assessing the ecological outcomes of wetland rehabilitation activities is an important need recognised by the ‘Working for Wetlands’ programme in South Africa. An assessment of ecological response was conducted in the Killarney and Kruisfontein wetlands, KwaZulu-Natal, in 2005 prior to rehabilitation in 2006, and again in 2011 and 2012, respectively, following rehabilitation. The assessment criteria included an evaluation of changes in ecological integrity, the supply of ecosystem services, and vegetation composition. Improvements in hydrological and geomorphic integrity were recorded in both wetlands, resulting in improved ecosystem delivery

WET-EcoServices Version 2: A revised ecosystem services assessment technique, and its application to selected wetland and riparian areas

A rapid assessment technique, termed WET-EcoServices, was developed 10 years ago to help assess the ecosystem services that individual wetland hydrogeomorphic units supply.  The technique requires the assessor to consider and score a suite of indicators (e.g., hydraulic roughness of the vegetation) which are then used to rate the ability of the wetland to provide 16 different ecosystem services. WET-EcoServices has become well entrenched in the South African context, with wetland specialists routinely using the technique to inform development planning, whilst it has also been used extensively in the wetland rehabilitation context. The technique has recently been revised, including the following key changes: (i) the technique is now more explicit in terms of distinguishing both ecosystem services’ supply and the demand for all ecosystem services assessed; (ii) the technique has been expanded to include non-wetland riparian areas; (iii) several of the indicators have been refined or replaced with indicators more relevant or appropriate for informing the rating of the ecosystem service or for which information is more readily available at a national level; and (iv) the algorithms used to integrate scores for the relevant indicators have been comprehensively refined so as to better account for the relative importance of the respective indicators. The aim of this paper is to present an overview of Version 2 of the technique and its underlying approach and then to demonstrate its application to 6 selected cases representing contrasting contexts, with a particular focus on the graphical representation of ecosystem service supply and demand for each case.  Some of the key emphases and approaches applied by WET-EcoServices are then discussed in relation to other published techniques widely used for assessing wetland ecosystem services.  After reflecting on some key limitations of WET-EcoServices, the paper concludes with recommendations on the technique’s potential contributions to operationalizing key broad imperatives of government.&nbsp