BackgroundAs the ecology of mosquito larvae can be complex there is need to develop a rational framework for undertaking larval ecological studies. Local environmental characteristics, such as altitude, climate and land use, can significantly impact on phenology and population dynamics of mosquito larvae, and indirectly affect the dynamics of mosquito-borne diseases. The aim of this study was to assess the feasibility of implementing an integrated approach to larval source management under the distinct ecological settings.MethodsThe study was conducted in two highland villages and one village, at a lower altitude, in the Lake Victoria basin, where malaria is endemic and transmitted by the same Anopheles mosquito species. In each village the stability of mosquito larval habitats was classified as either temporary or permanent. The productivity of these habitat types was quantified by carrying out weekly larval sampling using a standard dipping method for a period of two years. During sampling the physical characteristic of the larval habitat, including the vegetation cover were noted. Ambient temperature, rainfall and relative humidity were recorded on a 21 × Micro-datalogger in each study site.ResultsAnopheles gambiae sensu lato larvae were found in all study sites. Anopheles arabiensis was more abundant (93%) in Nyalenda (Lake Victoria basin) and Fort Ternan (highland area; 71%). In Lunyerere (highland area), An. gambiae sensu stricto comprised 93% of the total An. gambiae s.l. larvae. Larvae of An. gambiae s.l. mosquitoes were present in both temporary and permanent habitats with monthly variations dependent on rainfall intensity and location. Anopheles larvae were more likely to be found in man-made as opposed to natural habitats. Grassy habitats were preferred and were, therefore, more productive of Anopheles larvae compared to other habitat types. Weekly rainfall intensity led to an increase or decrease in mosquito larval abundance depending on the location.ConclusionThe majority of mosquito breeding habitats were man made in all sites. Both temporary and permanent habitats were suitable for An. gambiae breeding. In Fort Ternan temporary sites were favoured for mosquito breeding above permanent sites. Significant differences in larval abundance were found depending on weekly rainfall intensity. Larval source management programmes should target permanent and temporary habitats equally and work closely with land and home owners as a majority of the breeding habitats are man made.

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ABSTRACT. Issues of scale play a crucial role in the governance of social-ecological systems. Yet, attempts to bridge interdisciplinary perspectives on the role of scale have thus far largely been limited to the science arena. This study has extended the scale vocabulary to allow for the inclusion of practice-based perspectives on scale. We introduced "dimensions," used to describe the bare aspects of phenomena, such as time, space, and power, structured by scales and levels. We argued that this extension allows for a clearer understanding of the diversity of dimensions and scales that can be used to explore social-ecological systems. We used this scale vocabulary in a practical case study to elicit perspectives on dimensions, scales, and cross-dimensional dynamics from change agents in Dutch social-ecological systems. Through a visual interview method based in the extended scale vocabulary, our participants identified a large diversity of dimensions they saw as instrumental to understanding insights and lessons about effecting systems change. These dimensions were framed by a large number of scales to describe crossdimensional interactions. The results illustrate the value of practice-based perspectives for the development of scale theory. We also argue that the introduction of dimensions in the scale vocabulary is useful for clarifying scale theory aimed at linking different disciplines and sectors, and that the framework and methods based on it can also provide clarity for practical scale challenges.

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