Rethinking assessment of success of mitigation strategies for elephant-induced crop damage

Crop damage is the most common impact of negative interactions between people and elephants and poses a significant threat to rural livelihoods and conservation efforts. Numerous approaches to mitigate and prevent crop damage have been implemented throughout Africa and Asia. Despite the documented high efficacy of many approaches, losses remain common, and in many areas, damage is intensifying. We examined the literature on effectiveness of crop-damage-mitigation strategies and identified key gaps in evaluations. We determined there is a need to better understand existing solutions within affected communities and to extend evaluations of effectiveness beyond measurement of efficacy to include rates of and barriers to adoption. We devised a conceptual framework for evaluating effectiveness that incorporates the need for increased emphasis on adoption and can be used to inform the design of future crop-damage mitigation assessments for elephants and conflict species more widely. The ability to prevent crop loss in practice is affected by both the efficacy of a given approach and rates of uptake among target users. We identified the primary factors that influence uptake as local attitudes, sustainability, and scalability and examined each of these factors in detail. We argue that even moderately efficacious interventions may make significant progress in preventing damage if widely employed and recommend that wherever possible scientists and practitioners engage with communities to build on and strengthen existing solutions and expertise. When new approaches are required, they should align with local attitudes and fit within limitations on labor, financial requirements, and technical capacity.     

Whitefly wax as a cue for phoresy in the broad mite, <Emphasis Type="Italic">Polyphagotarsonemus latus</Emphasis>(Acari: Tarsonemidae)

Summary. Broad mite, Polyphagotarsonemus latus (Acari: Tarsonemidae) exhibits a specific phoretic relationship with whiteflies. Under field conditions most broad mites, caught in sticky traps, are attached to whiteflies. Under laboratory conditions, attachment occurs equally well in the dark and light. Mites do not differentiate between the sexes of their phoretic host Bemisia tabaci. However, mite attachment to B. tabaci is greatly diminished by washing the host with various organic solvents, chloroform in particular. The effect of whitefly waxy particles on broad mite behavior was studied using wax from the whitefly Aleyrodes singularis and from the mealybug Planococcus citri. Broad mites were not only attracted specifically to the A. singularis waxy particles-treated leaf areas but were also attached to leaf trichomes in this area. The results of this study suggests the importance of olfactory cues from the whitefly waxy particles in the recognition process of the phoretic host and/or the induction of the attachment behavior to whitefly legs or leaf trichomes.     

Contour Farming Based on Natural Vegetative Strips: Expanding the Scope for Increased Food Crop Production on Sloping Lands in Asia

In the agriculture of the future, there is a compelling place for agroecologically-based practices alongside practices based on the best available chemical, genetic, and engineering components. This paper explores this issue in the context of the development and spread of a conservation farming system based on natural vegetative contour buffer strips in smallholder production systems in southeast Asia. Farmers adapted contour hedgerow farming practices into a simpler, buffer-strip system as a labor-saving measure to conserve soil and sustain yields on steeply sloping cropland in Claveria, Mindanao, Philippines. Permanent-ridge tillage systems were also adapted to smallholder farming systems by researchers. Natural vegetative buffer strips resulted in gradually increasing yields, with an estimated benefit of 0.5t/ha/crop. They were seen to increase land values, facilitate investment in more intensive and profitable cropping systems, and expand the land base for food crop agriculture. They induced an institutional innovation of farmer-led Landcare organizations, which have spread this and other agroforestry practices to thousands of households in the southern Philippines.     

Future areas of investigation regarding the problem of urban road dust

In a number of metropolitan areas of the country, failure to attain national primary air quality standards for total suspended particulates (TSP) has fostered a detailed reexamination of the nature of the urban TSP problem. Reentrained dust from paved streets and other traffic-related emissions are now recognized as major sources of TSP in urban areas. While numerous reports and studies have examined this subject, some significant aspects of urban road dust have not been studied in enough detail, if at all. Examples of this are the effects of gutters and pavement composition and shape. This paper discusses those areas of the urban road dust problem that are felt to require further attention and outlines the priorities with which the data should be obtained.     

A MATHEMATICAL MODEL FOR OPTIMUM DESIGN AND CONTROL OF METROPOLITAN WASTEWATER MANAGEMENT SYSTEMS1

ABSTRACT: A comprehensive mathematical model (Urban Wastewater Management Model) has been developed to continuously simulate time-varying wastewater flows and qualities in complex metropolitan combined sewerage systems. The model serves three functions: (1) assessment of existing or planned system performance in relation to other wastewater discharges in either a metropolitan or river basin area; (2) determination of the optium operation or automatic control of existing or planned systems during rainstorms; and (3) determination of the most economically feasible combination of design alternatives for improving or expanding existing systems to meet specified performance criteria. The model provides an efficient engineering tool for evaluating and controlling pollutant discharges from combined sewerage systems (including treatment plants) to receiving waters, while considering the time and spacial variations of rainfall and dry-weather flows and qualities as well as economic constraints.     

CONTROL OF LAKE PHOSPHORUS WITH ALUMINUM SULFATE: DOSE DETERMINATION AND APPLICATION TECHNIQUES1

ABSTRACT: Nutrient diversion does not always bring about prompt and sufficient reduction in lake phosphorus concentration due to recycling from nutrient rich sediments. Certain lakes and reservoirs may continue to experience nuisance algal blooms and require additional restorative steps. The phosphorus precipitation/inactivation technique is a procedure to remove phosphorus from the water column and to control its release from sediments in order to achieve P-limiting conditions to algal growth. Aluminum salts have been used in advanced waste water treatment to remove phosphorus and this technology was extended to lake rehabilitation. Guidelines for dose calculation and application are generally lacking, and are provided in this report. The dose determination suggested here allows maximum application of aluminum to bottom sediments and thus emphasizes long term control of phosphorus recycling. Dose can be calculated directly from the alkalinity of the water to be treated. Titration of lake water samples of Varying alkalinity allows the establishment of the relationship between residual dissolved aluminum, alkalinity, and dose which can then be employed for lake scale applications of alum to lakes and reservoirs. Application equipment and procedures are described. These depend on site characteristics and treatment objectives and include lakeside stores, a distribution pipe, and an application barge and manifold. Alum may also be used to meet other restoration objectives including the treatment of problem flows and the reduction of particulate concentrations.