Climate change,food security,and livelihoods in sub-Saharan Africa

Sub-Saharan Africa is particularly vulnerable to climate change. Multiple biophysical, political, and socioeconomic stresses interact to increase the region’s susceptibility and constrain its adaptive capacity. Climate change is commonly recognized as a major issue likely to have negative consequences on food security and livelihoods in the region. This paper reviews three bodies of scholarship that have evolved somewhat separately, yet are inherently interconnected: climate change impacts, vulnerability and adaptation, food security, and sustainable livelihoods. The paper develops a conceptualization of the relationships among the three themes and shows how food security’s vulnerabilities are related to multiple stresses and adaptive capacities, reflecting access to assets. Food security represents one of several livelihood outcomes. The framework shows how several research paradigms relate to the issue of food security and climate change and provides a guide for empirical investigations. Recognizing these interconnections can help in the development of more effective policies and programs. The framework is applied here to synthesize findings from an array of studies in sub-Saharan Africa dealing with vulnerability to climate change, food security, and livelihoods.     

Advisory Committee: A Powerful Tool for Helping Decision Makers in Environmental Issues

/ It has been suggested that the general public should be moreinvolved in environmental policy and decision making. It is important forthem to realize that they will have to live with the consequences ofenvironmental policies and decisions. Consequently, policy makers shouldconsider the concerns and opinions of the general public before makingdecisions on environmental issues. This raises questions such as: How can weintegrate the perceptions and reactions of the general population inenvironmental decisions? What kind of public participation should weconsider? In the present study, using a new regional ecosystem model, weattempted to integrate these aspects in its decision making model byincluding the formation of an advisory committee to resolve problems relatedto waste management. The advisory committee requested the activeparticipation of representatives from all levels of the community: economic,municipal, and governmental intervenors; environmental groups; and citizens.Their mandates were to examine different management strategies available inthe region, considering all the interdisciplinary aspects of each strategy,elaborate recommendations concerning the management strategies that are mostsuitable for all, and collaborate in communication of the information to thegeneral population. The results showed that at least in small municipalitiessuch an advisory committee can be a powerful tool in environmental decisionmaking. Conditions required for a successful consultation process, such aseveryday lay language and the presence of a facilitator other than ascientific expert, are discussed.KEY WORDS: Public consultation; Environmental policies;Interdisciplinary aspects; Municipal sewage sludge management; Generalpopulation; Decision-making process     

Responses of indicator bacteria to forest soil amended with municipal sewage sludge from aerated and non-aerated ponds

The survival of faecal and total coliform bacteria and Streptococcus faecalis (indicator bacteria) were monitored in experimental plots receiving various amounts of biological or dephosphatation municipal sewage sludge. Biological sludge was applied on coniferous and mixed regenerative forest soils. The results show that except for total coliforms, there was little significant treatment effect on the indicator bacteria numbers in all of the sites. In most cases, there was a significant time effect, indicating that bacterial populations vary over time, according to environmental factors such as temperature, moisture or nutrient level conditions. In total coliform bacteria, populations varied over time but also in function of treatment levels. The present study suggests that even if the standards of Québec (Canada) for sludge application are respected, there may be some risk for bacterial contamination depending on the types of sewage sludge and forest habitat. Although there is only a short-term effect, high slopes can influence the movement of the indicator bacteria and may potentially cause some contamination problems.     

Spectral analysis unmasks synchronous and compensatory dynamics in plankton communities

Community biomass is often less variable than the biomasses of populations within the community, yet attempts to implicate compensatory dynamics between populations as a cause of this relationship often fail. In part, this may be due to the lack of appropriate metrics for variability, but there is also great potential for large-scale processes such as seasonality or longer-term environmental change to obscure important dynamics at other temporal scales. In this study, we apply a scale-resolving method to long-term plankton data, to identify the specific temporal scales at which community-level variability is influenced by synchrony or compensatory dynamics at the population level. We show that variability at both the population and community level is influenced strongly by a few distinct temporal scales: in phytoplankton, ciliate, rotifer, and crustacean communities, synchronous dynamics are predominant at most temporal scales. However, in phytoplankton and crustacean communities, compensatory dynamics occur at a sub-annual scale (and at the annual scale in crustaceans) leading to substantial reductions in community-level variability. Aggregate measures of population and community variability do not detect compensatory dynamics in these communities; thus, resolving their scale dependence unmasks dynamics that are important for community stability in this system. The methods and results presented herein will ultimately lead to a better understanding of how stability is achieved in communities.     

Exposure of Chironomus riparius larvae to uranium: effects on survival, development time, growth, and mouthpart deformities

Among non-biologically essential metals, data concerning uranium effects on freshwater benthic macroinvertebrates are scarce. The effects of uranium on survival, development time, growth and mouthpart deformities of midge Chironomus riparius were investigated. A 10-day static laboratory bioassay was performed exposing first instar larvae to artificial sediment spiked with four concentrations of uranium (2.97; 6.07; 11.44; 23.84 microg U g(-1) dry wt). As uranium was released from the sediment to the overlying water during this bioassay, both the sediment and the water column act as contamination pathways in giving rise to the observed effects. Significant negative effects on survival, development time, and growth were detected at 6.07, 6.07 and 2.97 microg U g(-1) dry wt, respectively. An LC20 of 2.49 microg U g(-1) dry wt (95% CI=1.48-4.27), and an LC50 of 5.30 microg U g(-1) dry wt (95% CI=3.94-7.25) were estimated. With respect to effects of uranium on larvae mouthpart deformities, we found that the lower the concentrations, the higher the deformity rates. These results highlight the potential impact of uranium at population level in environmentally realistic concentrations.     

Prenatal diagnosis of PIBIDS

In a well-documented PIBIDS family, two investigations of DNA excision repair showed a severe defect in lymphocytes from the index case (residual repair activities were 10.6–12.1 per cent). The values for the mother, father, and sister were within the normal range when compared with a healthy control. In the pregnant mother, a prenatal diagnosis of PIBIDS was made by measuring UV-induced unscheduled DNA synthesis in cultivated amniotic fluid cells. Results ranged between 12.5 and 26.1 per cent depending on the UV doses applied and were consistent with an affected fetus. The parents opted for a termination of pregnancy. Following a therapeutic abortion, fetal skin fibroblasts were tested and showed a severe DNA excision-repair defect of 9.2–13.5 per cent of residual activity.     

A dynamic explanation of size-density scaling in carnivores

Population abundance is negatively related to body size for many types of organisms. Despite the ubiquity of size-density scaling relationships, we lack a general understanding of the underlying mechanisms. Although dynamic models suggest that it is possible to predict the intercept and slope of the scaling relationship from prior observations, this has never been empirically attempted. Here we fully parameterize a set of consumer-resource models for mammalian carnivores and successfully predict the size-density scaling relationship for this group without the use of free parameters. All models produced similar predictions, but comparison of nested models indicated that the primary factors generating size-density scaling in mammalian carnivores are prey productivity, predator-prey size ratios, and consumer area of capture.     

Rapid quantitative monitoring method for the fish spoilage bacteria Pseudomonas

Pseudomonas spp. is a group of microorganisms commonly found in fish and other fresh foods and is involved in their spoilage process. The aim of this study was to develop a rapid and accurate quantitative assay for Pseudomonas spp. in fish using real-time PCR. The assay targets the carbamoyl phosphate synthase gene (carA) with SYBR green based real-time PCR. The selectivity of the assay was confirmed using 24 Pseudomonas strains and 55 non-pseudomonad strains. A linear quantification was established over seven orders of magnitude, from 40 - 4(7) copies reaction(-1). The assay was validated on cod samples collected during two shelf life trials and showed a high degree of correlation to the plate count method (rP = 0.891) where the difference between the methods was 0.04 log(10) CFU g(-1) on average. The study shows that it is possible to quantify accurately the specific spoilage organisms belonging to the genus Pseudomonas in fish using real-time PCR. The method takes less than 5 h from sampling to results. The short detection time of the method can provide the fish industry with an important tool for quality control and processing management.