Nikinake: the mobilization of labour and skill development in rural Ethiopia

A public mobilization approach known as nikinake drives implementation and technology upscaling in Ethiopia's agricultural extension. This study investigates and describes the processes and effectiveness of nikinake as an extension method used for natural resource management (NRM). The paper draws on empirical field research conducted in Oromia and the southern region of Ethiopia by looking at nikinake in the context of a watershed management campaign in 2015 and 2016. Nikinake is used as an approach to mobilize the public and to promote the skills of farmers and development actors. In principle, the implementation of NRM is voluntary; however, it is largely planned top‐down and enforced through state actors and informal institutions. This study suggests effective integration of social mobilization with reliable extension and a paradigm shift in emphasis from spatial coverage to an effective outcome. Additionally, sustainability and scalability of NRM interventions could be ameliorated by improving experts’ technical skills, raising farmers’ awareness, improving an incentive system, building trust, and better integrating past watershed management and future planning activities. We reflect on the significance of the nikinake experience in Ethiopia for a broader theory of extension‐as‐mobilization for rural development. From the Ethiopian case, a more general recommendation emerges for extension‐as‐mobilization schemes. For long‐term development, it is worthwhile to consider the fit between yearly campaigns as ad hoc project organizations and the existing pattern of actors and institutions responsible for rural development.     

Bird species and traits associated with logged and unlogged forest in Borneo.

The ecological consequences of logging have been and remain a focus of considerable debate. In this study, we assessed bird species composition within a logging concession in Central Kalimantan, Indonesian Borneo. Within the study area (approximately 196 km2) a total of 9747 individuals of 177 bird species were recorded. Our goal was to identify associations between species traits and environmental variables. This can help us to understand the causes of disturbance and predict whether species with given traits will persist under changing environmental conditions. Logging, slope position, and a number of habitat structure variables including canopy cover and liana abundance were significantly related to variation in bird composition. In addition to environmental variables, spatial variables also explained a significant amount of variation. However, environmental variables, particularly in relation to logging, were of greater importance in structuring variation in composition. Environmental change following logging appeared to have a pronounced effect on the feeding guild and size class structure but there was little evidence of an effect on restricted range or threatened species although certain threatened species were adversely affected. For example, species such as the terrestrial insectivore Argusianus argus and the hornbill Buceros rhinoceros, both of which are threatened, were rare or absent in recently logged forest. In contrast, undergrowth insectivores such as Orthotomus atrogularis and Trichastoma rostratum were abundant in recently logged forest and rare in unlogged forest. Logging appeared to have the strongest negative effect on hornbills, terrestrial insectivores, and canopy bark-gleaning insectivores while moderately affecting canopy foliage-gleaning insectivores and frugivores, raptors, and large species in general. In contrast, undergrowth insectivores responded positively to logging while most understory guilds showed little pronounced effect. Despite the high species richness of logged forest, logging may still have a negative impact on extant diversity by adversely affecting key ecological guilds. The sensitivity of hornbills in particular to logging disturbance may be expected to alter rainforest dynamics by seriously reducing the effective seed dispersal of associated tree species. However, logged forest represents an increasingly important habitat for most bird species and needs to be protected from further degradation. Biodiversity management within logging concessions should focus on maintaining large areas of unlogged forest and mitigating the adverse effects of logging on sensitive groups of species.     

An EM algorithm for capture-recapture estimation

Analysis of capture—recapture data often involves maximizing a complex likelihood function with many unknown parameters. Statistical inference based on selection of a proper model depends on successful attainment of this maximum. An EM algorithm is developed for obtaining maximum likelihood estimates of capture and survival probabilities conditional on first capture from standard capture—recapture data. The algorithm does not require the use of numerical derivatives which may improve precision and stability relative to other estimation schemes. The asymptotic covariance matrix of the estimated parameters can be obtained using the supplemented EM algorithm. The EM algorithm is compared to a more traditional Newton-Raphson algorithm with both a simulated and a real dataset. The two algorithms result in the same parameter estimates, but Newton-Raphson variance estimates depend on a numerically estimated Hessian matrix that is sensitive to step size choice.     

Bayesian Joint Estimation of Binary Outcome and Time-to-event Data: Effects of Leaf Quality on Pupal Survival and Time-to-Emergence in the Winter Moth

Plant–herbivore interactions are complex and affect herbivore fitness components and life history traits in many different ways. In this paper, we present results from an experiment studying the effects of leaf quality on pupal survival and duration of pupation (as measured by time-to-emergence) in the winter moth. Because only surviving pupae are at risk of emerging, analysis of time-to-emergence should exclude the dead pupae. However, due to right censoring, the survival status could not be determined for each individual. This failure to determine the group of moths at risk of emerging a priori motivated the development of a joint model of both survival probability and time-to-emergence. We formulate the model in a Bayesian framework and apply Monte Carlo Markov Chain (MCMC) to obtain posterior distributions. Time-to-emergence is modeled by a Cox Proportional Hazards (CPH) model where only the surviving pupae are at risk of emergence. Probability of pupal survival was modeled by a Generalized Linear Mixed Model (GLMM). The censored individuals were included in the analysis as a missing value in the GLMM. The GLMM then generated prior distributions of survival probabilties—and thus of the probability of being at risk of emergence—for these 19 individuals, conditional on the model parameters. The CPH model was formulated as a count process and the binary frailty was incorporated as a zero-inflated Poisson model. Zeros in this model represent the non-survivors. Leaf quality did not appear to influence time-to-emergence. Pupal survival was affected in a complex and unexpected way showing opposite effects in males and females. We also explored the robustness of our model against increased levels of censoring. While the degree of censoring was low in our study (< 1%), we artificially increased it to 67%. Although further study is required to study the generality of these results in a theoretical framework, our explorations suggest that the newly proposed technique may be widely applicable in a variety of situations where the identification of the at risk population cannot be done in a straightforward way. Received: January 2005 / Revised: June 2005     

Divided destinies: group choice by female savannah baboons during social group fission

Group living provides benefits to individuals while imposing costs on them. In species that live in permanent social groups, group division provides the only opportunity for nondispersing individuals to change their group membership and improve their benefit to cost ratio. We examined group choice by 81 adult female savannah baboons (Papio cynocephalus) during four fission events. We measured how each female’s group choice was affected by several factors: the presence of her maternal kin, paternal kin, age peers, and close social partners, her average kinship to groupmates, and her potential for improved dominance rank. Maternal kin, paternal kin, and close social partners influenced group choice by some females, but the relative importance of these factors varied across fissions. Age peers other than paternal kin had no effect on group choice, and average kinship to all groupmates had the same effect on group choice as did maternal kin alone. Most females were subordinate to fewer females after fissions than before, but status improvement did not drive female group choice; females often preferred to remain with social superiors who were their close maternal kin, rather than improving their own social ranks. We suggest that during permanent group fissions, female baboons prefer to remain with close maternal kin if those are abundant enough to influence their fitness; if they have too few close maternal kin then females prefer to remain with close paternal kin, and social bonds with nonkin might also become influential. Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

Parent-offspring aggression in moorhens

Summary Colonial orb-weaving spiders from Mexico were studied to test predictions of risksensitive foraging theory: 1. group foraging increases prey capture/individual, and reduces prey variance; 2. spiders should be expected to exhibit risk-averse behavior (forage in groups) when the average level of prey exceeds individual needs, and exhibit risk-prone behavior (forage solitarily) when prey are searce. Laboratory and field studies show that group foraging increases capture efficiency and reduces variability in prey captured per spider. In desert/mesquite grassland habitat, where prey availability is low, M. atascadero forage solitarily in most cases. In tropical rainforest/agriculture sites, M. increassata forage in large colonies of thousands of webs. In intermediate habitats, M. spinipes forages solitarily or in groups, depending on prey availability. Over a range of sites with varying levels of prey, M. spinipes shifts from a risk-prone to a risk-averse group foraging strategy as prey increases.Group foraging behavior observed in colonial Metepeira fits the predictions of risk-sensitive foraging models. These findings explain why spiders tend to group webs together only in areas of superabundant prey. The role of risk-sensitivity in the evolution of coloniality in spiders is discussed.     

Analysis of an intertidal population of the amphipod Gammarus palustris using a modified version of the egg-ratio method

An intertidal population of Gammarus palustris Bousfield was sampled over a 23-month period and analyzed by a modified form of the egg-ratio method. Total numbers and size-frequency distributions revealed small numbers in the early spring which later increased to a peak in the summer months. This was followed by a marked reduction near the end of sumer and a subsequent rise in numbers during the early fall. Finally there was a second decrease to very low numbers in the late fall and early winter. Average brood size was calculated and used as an indication of food limitation. Attempts to correlate this with per capita rate of change (r), birth rate ( \((\hat b)\) and death rate ( \((\hat d)\) ) suggested that the population increase in the early summer was food-rather than predator-limited. The late summer decline appears to be the result of predation pressure as well as food limitation. The fall peak is attributed to juvenile release from ovigerous femals escaping previous predation and to an increase in adult males resulting from a release in predation pressure. The winter decline may be due to adverse environmental conditions.     

Kin discrimination in the spotted hyena (<Emphasis Type="Italic">Crocuta crocuta</Emphasis>): nepotism among siblings

We examined patterns of affiliation, association, and aggression to inquire whether spotted hyenas (Crocuta crocuta) can distinguish among various groups of maternal and paternal siblings. If so, and if these animals conform to predictions of kin selection theory, then behavioral interactions among hyenas should vary with relatedness. We also considered familiarity-based recognition and phenotype matching as mechanisms hyenas might use to recognize kin. Patterns of affiliative behavior indicated that hyenas favored full-sibling littermates over half-sibling littermates or any other group of half-siblings. Rates of dyadic aggression generally did not vary with kinship. Hyenas associated more closely with half-sibling littermates than with non-littermate half-siblings, and hyenas affiliated more with maternal half-siblings than with paternal half-siblings, suggesting that familiarity-based cues might mediate discrimination among these sibling classes. In addition, operation of a phenotype-matching mechanism was suggested by the preference hyenas demonstrated during affiliative interactions for full- over half-sibling littermates, and by their lack of preference in these interactions for half-sibling littermates over non-littermate half-siblings. Phenotype matching was also suggested by our observation that paternal half-siblings cooperated more, and fought less, than did non-kin. Our data indicate that hyenas can discriminate among various types of siblings, that their social behavior conforms to predictions of kin selection theory, and that they recognize kin using mechanisms of both familiarity and phenotype matching.Communicated by S. Alberts     

The cost of mating with a non-virgin male in a monandrous butterfly: experimental evidence from the speckled wood, Pararge aegeria

Contrary to vertebrates, sperm production in insects may bear considerable costs for males. This is especially true in species that donate spermatophores containing sperm and nutrient-rich accessory gland products like in butterflies. Hence, spermatophores at first and subsequent copulations can differ in a quantitative and qualitative way. Such effects have particularly been shown in polyandrous species providing large spermatophores. Here we experimentally tested the effect of male mating status (virgin male vs recently mated male) on copulation duration, spermatophore size and females’ fitness components in a monandrous butterfly Pararge aegeria that typically donates small spermatophores. Copulations with non-virgin males lasted on average five times longer than that with virgin males and resulted in a spermatophore which was on average three times smaller. Number of eggs laid and female life span were not affected by the mating status treatment, but there was a significant effect on the number of living caterpillars a female produced, as copulations with virgin males resulted in higher numbers of larval offspring. Interestingly, the difference in spermatophore mass at the first and the second copulation increased with male body size. This suggests differential spermatophore allocation decisions among males of different size. Consequences for females and potential mechanisms influencing female fitness components are discussed. Given the small absolute size of spermatophores in P. aegeria, components other than consumable nutrients (perhaps hormones) should cause the observed effects.