Salerno J, Mwalyoyo J, Caro T, Fitzherbert E, Borgerhoff Mulder M. 2017. Consequences of internal migrationBioScience.

Internal or within-state migration is common in Africa and elsewhere and has environmental and social consequences that are often poorly understood. We conducted a national-scale study tracking the movements of agropastoralists in Tanzania and documented the extent of associated environmental changes. P1030805The data were drawn from interviews with government officials in 80 rural districts covering the majority of land area across the country. According to interviewees, recent settlement is associated with forest clearing, overgrazing, and landscape burning. Conflicts such as lion killing and forced evictions of settlers often occur. Our interview data uncover limited capacity and lack of coordination among different levels of government to deal with these challenges. The novelty of our study is in its ability to draw on reports from ground-level administrators and to aggregate this information in order to both describe the impacts of rural migration over a large area and inform appropriate policy action from national-level decision-makers.


Salerno J, Ross N, Ghai R, Mahero M, Travis DA, Gillespie TP, Hartter J. Human-wildlife interactions predict febrile illness in park landscapes of western Uganda. 2017. EcoHealth.

OLYMPUS DIGITAL CAMERAFevers of unknown origin complicate treatment and prevention of infectious diseases and are a global health burden. We examined risk factors of self-reported fever — categorized as “malarial” and “nonmalarial” — in households adjacent to national parks across the Ugandan Albertine Rift, a biodiversity and emerging infectious disease hotspot. Statistical models fitted to these data suggest that perceived nonmalarial fevers of unknown origin were associated with more frequent direct contact with wildlife and with increased distance from parks where wildlife habitat is limited to small forest fragments. Perceived malarial fevers were associated with close proximity to parks but were not associated with direct wildlife contact. Self-reported fevers of any kind were not associated with livestock ownership. These results suggest a hypothesis that nonmalarial fevers in this area are associated with wildlife contact, and further investigation of zoonoses from wildlife is warranted. More generally, our findings of land use-disease relationships aid in hypothesis development for future research in this social-ecological system where emerging infectious diseases specifically, and rural public health provisioning generally, are important issues.


Salerno J, Cassidy L, Drake M, Hartter J. 2017. Cover/feature article: Living in an elephant landscape. American Scientist.



Salerno J, Chapman C, Diem JE, Dowhaniuk N, Goldman A, MacKenzie CA, Omeja PA, Palace MW, Reyna-Hurtado R, Ryan SJ, Hartter J. 2017. Review article: The future of isolated tropical parks in anthropogenic landscapes: A social-ecological test case of the Albertine Rift of Africa. Regional Environmental Change.

Across tropical regions, landscapes containing rural people living adjacent to protected parks and reserves are changing rapidly.  This is the case in highland EaP1040326st Africa, where many such parks are increasingly isolated in a matrix of small farms and settlements. In this paper we assess the state of park isolation in the Ugandan Albertine Rift using extant, coarse data sources of human population and forest cover (1995-2015). We review and synthesize findings from our long-term research program in the region, focusing primarily on the unprotected landscape, and on the interactions between people and parks in boundary areas.  Using what we term a modified whole-landscape assessment, we explain the trends in population and forest change in order to provide context to the observed changes. We discuss potential compounding factors such as changing climate, land tenure, and soil fertility, which may accelerate effects of population growth on unprotected forest loss and park isolation.  Increasing isolation of parks affects multiple outcomes in the surrounding human landscape, such as high frequency of human-wildlife conflict, potential for zoonotic disease transmission, and increased land competition and commercialization. Our review suggests that whole-landscape strategies to prevent or reverse park isolation cannot be effectively implemented across the Ugandan Albertine Rift. We instead argue that the majority of parks in this system are already or will soon be isolated. We provide recommendations for management of isolated parks through a modified whole-landscape strategy, which includes park authorities augmenting their outreach and community support in the human landscape, while also maintaining hard boundaries through traditional protectionism. The significance of this article is in its use of a long-running research program to explain population and forest change evident at a regional scale, as well as its modification of a whole-landscape perspective recommended to support better human and biodiversity outcomes in the highland tropics.


Kline M, Waring T, Salerno J. 2017. Designing cultural multilevel selection research for sustainability science. Sustainability Science.

Humans stand out among animals in that we cooperate in very large groups to exploit natural resources, and accumulate survival and resource exploitation strategies across generations via cultural learning. This uniquely human form of adaptability is in large part to blame for the global sustainability crisis. P1040269This paper leverages cultural evolutionary theory to gain a better understanding of how human cultural capacities got us to this point of overuse and resource scarcity. Because cultural evolutionary forces are at the core of many sustainability crises, particularly social dilemmas, we offer an explicitly evolutionary approach to study how such crises emerge, persist, or disappear. To do so, build on a brief primer on cultural evolution to provide an explanation of how group-level cultural adaptations for resource use evolve. This includes stipulating heuristics and empirical criteria that are ready for direct implementation in sustainability science, with both novel and existing data sets. Building on this foundation, we provide a step-by-step tutorial for designing a study of group-level cultural adaptation and selection, including the major methodological considerations that researchers should address in study design. We conclude by offering guidance on how to evaluate a conglomeration of evidence as a whole, with an eye toward synthesizing across new and existing data sets, including case studies.


MacKenzie CA, Salerno J, Hartter J, Chapman C, Reyna-Hurtado R, Tumusiime DM, Drake M. 2017. Changing perceptions of protected area benefits and troubles around Kibale National Park, Uganda. Journal of Environmental Management.

Local residents’ changing perceptions of benefits and troubles accrued as a result of living next to a protected area in western Uganda are assessed by comparing household survey data from 2006, 2009 and 2012.  vert_treeSurvey findings are contextualized and supported by separate long-term data sources for tourism, research, and reforestation employment, tourism revenue sharing, resource access agreements, and problem animal abundance.  We find that perceptions of benefit from the protected area are decreasing over time and are primarily informed by access to protected area-based employment and resource access, while perceptions of trouble are increasing over time, driven by the perceived increase in crop raiding as the elephant population inside the protected area recovers.  People will always hold both positive and negative perceptions about protected areas, but as human and animal populations rise, wildlife authorities in Sub-Saharan Africa will be challenged to balance perceptions and adapt policies to ensure the continued existence of protected areas.  Understanding the dynamic nature of local people’s perceptions provides a tool to adapt protected area management plans to react to changing perceptions and externalities, as well as prioritizing limited conservation resources.



In the pipe

Salerno J, Andersson K, Mwaviko K, Donad I, Mangewa LJ, Hartter J. Moving from cash to cooperation and better governance: How community-based conservation should shift goals to benefit people. In review. Conservation letters.

Community-based conservation (CBC) is essential to promoting biodiversity protection and livelihood development. Despite significant financial and institutional support, performance of CBC projects is mixed. Shortcomings are especially evident in wildlife-based CBC in Africa. 20170508_154523While most existing studies focus on livelihoods and environmental outcomes, we propose an important additional dimension for project impact assessments: local governance capacity. Strengthened governance can enable local groups to address existing and future challenges more effectively. We use quasi-experimental methods to test this argument in a conservation landscape in Tanzania. Employing multilevel Bayesian latent trait models, we find that CBC participation predicts stronger local governance institutions. Compared to control villages, CBC villages have more local businesses and civic organizations, but do not experience more elite capture of public goods. We show that even in the absence of direct benefits to environmental conservation or livelihoods, CBC programs can have cumulative positive impacts through strengthening local governance institutions.


Salerno J, Diem J, Konecky BE, Hartter J. Recent intensification of the seasonal rainfall cycle in equatorial Africa revealed by farmer observations, satellite-based estimates, and station measurements. In review. Climatic Change.

Smallholder farmers in sub-Saharan Africa are on the frontlines of climate variability and change. In rainfed systems, farmer observations of changing rainfall and weather patterns are important precursors for annual cropping decisions and longer-term adaptation. This is especially true in regions where poor scientific understanding of climate controls and trends limits useful forecasting and climate services available locally. elephant-browsing-damage-n-bots_cassidy.jpgWe propose that combining farmer observations of trends in seasonal rainfall with satellite-based rainfall estimates and weather station data can resolve uncertainties regarding regional climatic change. In a climatically complex and remote transition zone between East and central Africa, data from 987 farming households suggest distinct changes in seasonal bimodal rainfall over recent decades. Data from three satellite-based rainfall products spanning 34 years largely corroborate farmer observations, showing wetter rainy seasons and drier dry seasons, particularly in the southern-most sites. Interestingly, one site shows uncertainty and the absence of seasonal trends from farmer observations, satellite-based products, and ground-based data, suggesting anomalous local climate. In addition, combining all three information sources suggests a weak increasing trend, if any, in annual rainfall, most prominently in the north; this runs counter to recent research asserting the presence of a drying trend. Our study is unique in evaluating these multiple data sources to identify climatic change affecting people in a less-understood region, along with providing insights into the accuracy of existing information sources and of regional-scale climate controls.


Niles M and Salerno J. A cross-country analysis of climate shocks and smallholder food insecurity. In revision with  PLoS ONE.

Future climate changes will affect smallholder farmers in the developing world, posing threats to household food security.  There remains limited comparable evidence regarding the global extent of climate shocks affecting smallholder food security.  We examine data from 5,299 household surveys across 15 countries in Latin America, Africa, and South Asia to assess the extent of climate shocks and their associatioLittle farmern with food insecurity, the role that assistance plays in reducing food insecurity following a climate shock, and what strategies may help buffer against climate shocks. We find that 71% of households reported experiencing a climate shock in the previous five years, but only 31% of these received assistance.  Fifty-four percent reported experiencing food insecurity during one or more months annually.  A multilevel statistical model estimated significant associations between perceived climate shock and food insecurity, though households receiving assistance were associated with more severe food insecurity, likely because they are the most vulnerable. Access to productive capacities such as fertilizers, pesticides, veterinary medicines, and livestock is associated with decreased food insecurity following a climate shock; accessing credit may reduce food insecurity among households receiving assistance. Together, results demonstrate the profound extent of existing climate shocks affecting smallholder farmers and the potential for interventions to alleviate negative effects.


[see cv for a more current publication list]


On the books

Salerno J. 2016. Migrant decision-making in a frontier landscapeEnvironmental Research Letters 11:044019.

Across the tropics, rural farmers and livestock keepers use mobility as an adaptive livelihood strategy.  Continued migration to and within frontier areas is largely viewed as a driver of environmental decline and biodiversity loss.  Recent scholarship advances our understanding of migration decision-making in the context of changing climate and environments, and in doing so it highlights the variation in migration responses to largely economic and environmental factors.  Building on these insights, this letter investigates past and future migration decisions in a frontier landscape of Tanzania, East Africa.  Combining field observations and household data within a multilevel modelling framework, this letter analyses the explicit importance of social factors relative to economic and environmental factors in driving migration decisions.  Results indeed suggest that local community ties and non-local social networks drive both immobility and anticipated migration, respectively, for different households.  Suk mbugani tela2_enhIn addition, positive interactions with local protected natural resource areas promote longer-term residence.  Findings are interpreted in light of how the migration literature understands changing frontier areas as they transition to human dominated landscapes.  This highlights critical links between migration behaviour and the conservation of biodiversity and management of natural resources, as well as how migrants evolve to become integrated into communities.


Diem JE, Hartter J, Salerno J, McIntyre E. Grandy AS. 2016. Comparison of measured multi-decadal rainfall variability with farmers’ perceptions of and responses to seasonal changes in western Uganda. Regional Environmental Change doi:10.1007/s10113-016-0943-1.

Smallholder farmers in sub-Saharan Africa (SSA) are not only dealing with decreased production from land degradation, but are also impacted heavily by climate variability. Farmers perceive decreased rainfall or shortened rainy seasons throughout SSA; however, the link between perceptions and climate variability is complex, especially in areas with increasing land degradation. OLYMPUS DIGITAL CAMERAMoreover, little is known about climate variability and farmers’ perceptions in central equatorial Africa. The purpose of this study is to quantify inter-annual rainfall variability from 1983-2014 in western Uganda and to relate the rainfall variability and associated changes in soil moisture to perceptions and coping strategies of local farmers. Surveys of 308 farming households and 14 group interviews were conducted near Kibale National Park, and daily satellite- based rainfall data for the region were extracted from the African Rainfall Climatology version 2 database. Results indicate a decrease in the long rains by approximately three weeks throughout much of the region; thus, soil-water deficits have intensified. Farmers perceived later onsets of both the short rains and long rains, while also reporting decreasing soil fertility and crop yields. Therefore, farmers’ perceptions of rainfall variability in the Kibale region may reflect more the decrease in soil fertility than the shortened rainy seasons and decreased soil moisture. Expanding croplands has been the farmers’ most prevalent coping strategy to decreased yields; however, nearly all the unfarmed land in western Uganda is now in protected areas. Consequently, western Uganda is facing a crisis at the nexus of population growth, land use change, and climate change.


Salerno J, Borgerhoff Mulder M, Grote MN, Ghiselli M, Packer C. 2015. Household livelihoods and wildlife conflict in community-based conservation areas across northern Tanzania. Oryx 50(4).

Conservation strategies to protect biodiversity and support household livelihoods face numerous challenges. Across the tropics, efforts focus on balancing trade-offs in local communities near the borders of protected areas. Devolving rights and control over certain resources to communities is increasingly considered necessary, but decades of attempts have yielded limited success and few lessons on how such interventions could be successful in improving livelihoods. We investigated a key feature of household well-being, the experience of food insecurity, in villages across Tanzania’s northern wildlife tourist circuit. Using a sample of 2,499 primarily livestock-keeping households we compared food insecurity in villages participating in the country’s principal community-based conservation strategy with nearby control areas. We tested whether community-based projects could offset the central costs experienced by households near strictly protected areas (i.e. frequent human–wildlife conflict and restricted access to resources). We found substantial heterogeneity in outcomes associated with the presence of community-based conservation projects across multiple project sites. OLYMPUS DIGITAL CAMERAAlthough households in project villages experienced more frequent conflict with wildlife and received few provisioned benefits, there is evidence that these households may have been buffered to some degree against negative effects of wildlife conflict. We interpret our results in light of qualitative institutional factors that may explain various project outcomes. Tanzania, like many areas of conservation importance, contains threatened biodiversity alongside areas of extreme poverty. Our analyses highlight the need to examine more precisely the complex and locally specific mechanisms by which interventions do or do not benefit wildlife and local communities.


Salerno J, Borgerhoff Mulder M, and Kefauver S. 2014. Human migration, protected areas, and conservation outreach in Tanzania. Conservation Biology 28(3):841-850.

A recent discussion debates the extent of human in-migration around protected areas (PAs) in the tropics. One proposed argument is that rural migrants move to bordering areas to access conservation outreach benefits. A counter proposal maintains that PAs have largely negative effects on local populations and that outreach initiatives even if successful present insufficient benefits to drive in-migration. Kaulack-Kaffrine hut_cropUsing data from Tanzania, we examined merits of statistical tests and spatial methods used previously to evaluate migration near PAs and applied hierarchical modeling with appropriate controls for demographic and geographic factors to advance the debate. Areas bordering national parks in Tanzania did not have elevated rates of in-migration. Low baseline population density and high vegetation productivity with low interannual variation rather than conservation outreach explained observed migration patterns. More generally we argue that to produce results of conservation policy significance, analyses must be conducted at appropriate scales, and we caution against use of demographic data without appropriate controls when drawing conclusions about migration dynamics.


Packer C, Loveridge A, Canney S, and 42 others including Salerno JD. 2013. Conserving large carnivores: Dollars and fence. Ecology Letters 16:635-641.

Conservationists often advocate for landscape approaches to wildlife management while others argue for physical separation between protected species and human communities, but direct empirical comparisons of these alternatives are scarce. We relate African lion population densities and population trends to contrasting management practices across 42 sites in 11 countries. Lion populations in fenced reserves are significantly closer to their estimated carrying capacities than unfenced populations. Whereas fenced reserves can maintain lions at 80% of their potential densities on annual management budgets of $500 km−2, unfenced populations require budgets in excess of $2000 km−2 to attain half their potential densities. Cattle, sheep, goats and Baobab treeLions in fenced reserves are primarily limited by density dependence, but lions in unfenced reserves are highly sensitive to human population densities in surrounding communities, and unfenced populations are frequently subjected to density-independent factors. Nearly half the unfenced lion populations may decline to near extinction over the next 20–40 years.


Salerno JD, Msalu L, Caro T, Borgerhoff Mulder M. 2012. Risk of injury and death from lightning in Northern Malawi. Natural Hazards 52:481-499.

Rates of lightning mortality in communities on the western shore of Lake Malawi are higher than any other reported rate in the world: 419 strike victims per million people per annum and 84 deaths per million per annum. To document the background to this phenomenon, we conducted comprehensive household interviews with surviving victims and witnesses of every case of lightning strike in seven administrative areas around Nkhata Bay, Malawi. We find that the consequential lightning strikes are significantly more common in the rainy season and during the morning. Among those victims struck by lightning, there is an average ratio of approximately one death to four injuries, which is substantially higher than the commonly accepted ratio of 1:10. Gray crowned crane_CrEnhChildren and adults are at equal risk of being struck. If struck, the probability of death is greater when the victim is outside in the open or outside under cover than indoors under a tin or thatched roof, but is unaffected by different kinds of footwear or whether it is raining. Reported explanations for strikes often center on witchcraft or other forms of social conflict. Our findings extend the study of consequential lightning strikes in the developing world and highlight cultural factors associated with this hazard. We end with recommendations for reducing the risk of lightning for rural populations.


Borgerhoff Mulder M, Msalu L, Caro T, Salerno JD. 2012. Remarkable rates of lightning strike mortality in Malawi. PLoS ONE 7:e29281.

Livingstone’s second mission site on the shore of Lake Malawi suffers very high rates of consequential lightning strikes. Comprehensive interviewing of victims and their relatives in seven Traditional Authorities in Nkhata Bay District, OLYMPUS DIGITAL CAMERAMalawi revealed that the annual rate of consequential strikes was 419/million, more than six times higher than that in other developing countries; the rate of deaths from lightning was 84/million/year, 5.4 times greater than the highest ever recorded. These remarkable figures reveal that lightning constitutes a significant stochastic source of mortality with potential life history consequences, but it should not deflect attention away from the more prominent causes of mortality in this rural area.