Image courtesy PLoS ONE.

WALTHERNetwork analysis of regional livestock trade in West Africa

Valerie C. Valerio, Olivier J. Walther, Marjatta Eilittä, Brahima Cissé, Rachata Muneepeerakul, Gregory A. Kiker

Article first published online: 14 MAY 2020 PLoS ONE

DOI: 10.1371/journal.pone.0232681

ABSTRACT: In West Africa, long and complex livestock value chains connect producers mostly in the Sahel with consumption basins in urban areas and the coast. Regional livestock trade is highly informal and, despite recent efforts to understand animal movement patterns in the region, remains largely unrecorded. Using CILSS’ database on intraregional livestock trade, we built yearly and overall weighted networks of animal movements between markets. We mapped and characterized the trade networks, identified market communities, key markets and their roles. Additionally, we compared the observed network properties with null-model generated ensembles. Most movements corresponded to cattle, were made by vehicle, and originated in Burkina Faso. We found that live animals in the central and eastern trade basins flow through well-defined, long distance trade corridors where markets tend to trade in a disassortive way with others in their proximity. Modularity-based communities indicated that both national and cross-border trade groups exist. The network’s degree and link distributions followed a log-normal or a power-law distribution, and key markets located primarily in urban centers and near borders serve as hubs that give peripheral markets access to the regional network. The null model ensembles could not reproduce the observed higher-level properties, particularly the propinquity and highly negative assortativity, suggesting that other possibly spatial factors shape the structure of regional live animal trade. Our findings support eliminating cross-border impediments and improving the condition of the regional road network, which limit intraregional trade of and contribute to the high prices of food products in West Africa. Although with limitations, our study sheds light on the abstruse structure of regional livestock trade, and the role of trade communities and markets in West Africa.

Read the full publication at PLoS ONE.





Image courtesy PLoS ONE.

GAINESVILLE, FL – In a new paper published in PLoS ONE today, Dr. Olivier Walther and colleagues produced the first comprehensive mapping of the West African livestock trade network. Their network analysis of more than 42,000 movements from 2013-17 shows that live animals flow through well-defined, long distance trade corridors and that border markets are important hubs in the regional network. The paper was co-authored by Valerie C. Valerio (lead author, UF), Olivier J. Walther (UF), Marjatta Eilittä, Brahima Cissé, Rachata Muneepeerakul (ABE, UF), Gregory A. Kiker (ABE, UF)

Read Network analysis of regional livestock trade in West Africa in PLoS ONE.

Malaria risk shifting with climate change in Africa – seasonal (7-9 months) and endemic (10-12 months) risk shift geographically under the two projected climate change scenarios, leading to different number of people at risk (of endemic transmission) across the four regions, over time. (Figure adapted from Ryan et al, 2020)

GAINESVILLE, FL – In a new paper in Malaria Journal “Shifting transmission risk for malaria in Africa with climate change: a framework for planning and intervention”, part of a cross-journal collection on the Contribution of Climate Change to Spread of Infectious Disease, QDEC’s Sadie J. Ryan, along with Cat A. Lippi and collaborator Fernanda Zermoglio (M.S. UF Geography ‘00) show how projected climate change will alter malaria transmission potential patterns, placing populations at risk in different parts of Africa in 2030, 2050, and 2080, under different emissions scenarios. Funded by the USAID ATLAS (Adaptation, Thought, Leadership, and Assessments) project, this study aimed to describe how regional changes in risk would affect different places and populations in different ways, relevant to decision making for intervention.

Malaria interventions for seasonal outbreaks differ from managing year-round risk, so understanding where these patterns will change is important for both anticipating new regions at risk, and where to change health infrastructure and capacity. In Western Africa, there is a massive drop in the number of people at risk of year-round malaria transmission, but this is a function of increasing temperatures, putting much of the region at hotter temperatures than the mosquitoes best transmit. The region expecting the greatest risk increase by 2080, in terms of people, is the densely populated Eastern Africa, where seasonal risk will increase and push into novel areas, according to predictions.

This regional approach to thinking about where malaria transmission will change is important to global health policy. “It’s hard to communicate the intersection of demography and geographic risk, so aligning our scales with those at which decisions are often made is useful” Dr Ryan points out. Mapping disease risk is not enough, she continued, because we make decisions based on how many people, and when, not just where.

Read the whole paper at Malaria Journal.

Image courtesy Malaria Journal

LIPPI, RYANShifting transmission risk for malaria in Africa with climate change: a framework for planning and intervention

Sadie J. Ryan, Catherine A. Lippi, & Fernanda Zermoglio

Article first published online: 01 MAY 2020 Malaria Journal

DOI: 10.1186/s12936-020-03224-6


Malaria continues to be a disease of massive burden in Africa, and the public health resources targeted at surveillance, prevention, control, and intervention comprise large outlays of expense. Malaria transmission is largely constrained by the suitability of the climate for Anopheles mosquitoes and Plasmodium parasite development. Thus, as climate changes, shifts in geographic locations suitable for transmission, and differing lengths of seasons of suitability will occur, which will require changes in the types and amounts of resources.

The shifting geographic risk of malaria transmission was mapped, in context of changing seasonality (i.e. endemic to epidemic, and vice versa), and the number of people affected. A published temperature-dependent model of malaria transmission suitability was applied to continental gridded climate data for multiple future AR5 climate model projections. The resulting outcomes were aligned with programmatic needs to provide summaries at national and regional scales for the African continent. Model outcomes were combined with population projections to estimate the population at risk at three points in the future, 2030, 2050, and 2080, under two scenarios of greenhouse gas emissions (RCP4.5 and RCP8.5).

Estimated geographic shifts in endemic and seasonal suitability for malaria transmission were observed across all future scenarios of climate change. The worst-case regional scenario (RCP8.5) of climate change predicted an additional 75.9 million people at risk from endemic (10-12 months) exposure to malaria transmission in Eastern and Southern Africa by the year 2080, with the greatest population at risk in Eastern Africa. Despite a predominance of reduction in season length, a net gain of 51.3 million additional people is predicted be put at some level of risk in Western Africa by midcentury.

This study provides an updated view of potential malaria geographic shifts in Africa under climate change for the more recent climate model projections (AR5), and a tool for aligning findings with programmatic needs at key scales for decision-makers. In describing shifting seasonality, it was possible to capture transitions between endemic and epidemic risk areas, to facilitate the planning for interventions aimed at year-round risk versus anticipatory surveillance and rapid response to potential outbreak locations.

Read the full publication at Malaria Journal





Image courtesy Applied Sciences.

BUNTING, CHILD, HERRERO, KHATAMI, MUIR, SOUTHWORTHAn Evaluation of Vegetation Health in and around Southern African National Parks during the 21st Century (2000–2016)

Hannah Herrero, Jane Southworth, Carly Muir, Reza Khatami, Erin Bunting, and Brian Child

Article first published online: 30 MAR 2020 Applied Sciences

DOI: 10.3390/app10072366

ABSTRACT: Roughly 65% of the African continent is classified as savanna. Such regions are of critical importance given their high levels of biological productivity, role in the carbon cycle, structural differences, and support of large human populations. Across southern Africa there are 79 national parks within savanna landscapes. Understanding trends and factors of vegetation health in these parks is critical for proper management and sustainability. This research strives to understand factors and trends in vegetation health from 2000 to 2016 in and around the 79 national parks across southern Africa. A backward stepwise regression was used to understand the factors (e.g., precipitation, population density, and presence of transfrontier conservation areas) affecting the normalized difference vegetation index (NDVI) during the 21st century. There was a statistically significant positive (p < 0.05) relationship between mean annual precipitation and NDVI, and a significant negative relationship between population density and NDVI. To monitor vegetation trends in and around the parks, directional persistence, a seasonal NDVI time series-based trend analysis, was used. Directional persistence is the net accumulation of directional change in NDVI over time in a given period relative to a fixed benchmarked period. Parks and buffer zones across size classes were compared to examine differences in vegetation health. There was an overwhelmingly positive trend throughout. Additionally, national parks, overall, had higher amounts of positive persistence and lower amounts of negative persistence than the surrounding buffer zones. Having higher positive persistence inside of parks indicates that they are functioning favorably relative to the buffer zones in terms of vegetation resilience. This is an important finding for park managers and conservation overall in Southern Africa.

Read the full publication at Applied Sciences




Image courtesy OECD Report.

WALTHERThe Geography of Conflict in North and West Africa

Olivier Walther

Article first published online: 14 FEB 2020 OECD Report

DOI: 10.1787/02181039-en

ABSTRACT: African governments are increasingly confronted with new forms of political violence. The situation is particularly worrying in the Sahara-Sahel where violence is on the rise. This degrading security situation has prompted African countries and their partners to intervene militarily to stabilise the region and to prevent the spread of extremism and violence against civilians. However, these initiatives face many obstacles due to the transnational nature and geography of violence. Tensions regionalise across state borders when armed groups, defeated by counter-insurgency efforts, relocate to other countries. This study maps the evolution of violence across North and West Africa, with a particular focus on Mali, Lake Chad and Libya. In the regions experiencing the highest levels of political insecurity, it identifies whether and how conflicts tend to cluster or spread, potentially across national borders. The work is based on a new spatial indicator of political violence designed to assess the long-term evolution of conflicts and provide policy options.

Read the full publication at the OECD Report on The Geography of Conflict in North and West Africa 





Image courtesy Remote Sensing.

CHILD, HERRERO, KHATAMI, SOUTHWORTH, WAYLEN, YANGA Healthy Park Needs Healthy Vegetation – The Story of Gorongosa National Park in the 21st Century

Hannah Herrero, Peter Waylen, Jane Southworth, Reza Khatami, Di Yang, Brian Child

Article first published online: 03 FEB 2020 Remote Sensing

DOI: 10.3390/rs12030476

ABSTRACT: Understanding trends or changes in biomass and biodiversity around conservation areas in Africa is important and has economic and societal impacts on the surrounding communities. Gorongosa National Park, Mozambique was established under unique conditions due to its complex history. In this study, we used a time-series of Normalized Difference Vegetation Index (NDVI) to explore seasonal trends in biomass between 2000 and 2016. In addition, vegetation directional persistence was created. This product is derived from the seasonal NDVI time series-based analysis and represents the accumulation of directional change in NDVI relative to a fixed benchmark (2000–2004). Trends in precipitation from Climate Hazards Group InfraRed Precipitation with Station data (CHIRPS) was explored from 2000–2016. Different vegetation covers are also considered across various landscapes, including a comparison between the Lower Gorongosa (savanna), Mount Gorongosa (rainforest), and surrounding buffer zones. Important findings include a decline in precipitation over the time of study, which most likely drives the observed decrease in NDVI. In terms of vegetation persistence, Lower Gorongosa had stronger positive trends than the buffer zone, and Mount Gorongosa had higher negative persistence overall. Directional persistence also varied by vegetation type. These are valuable findings for park managers and conservationists across the world.

Read the full publication at Remote Sensing





University of Florida Department of Geography
The Navi-Gator
February 2020, ISSUE 4 (Download PDF)

Evening of excellence
Congratulations to our winners! We loved having you all for a night of celebration, reward and remembrance!
Anderson Award for International Travel- Leandra Merz

Top Published Research Articles- Mehedy Hassan for Geospatial Analysis and Techniques & Global, Environmental, and Social Change
Cat Lippi & Stephanie Mundis for Medical Geography in Global Health
Evan Coe Award in Medical Geography- Stephanie Mundis

Spread the Word!
University of Florida in South Africa
Application Deadline: February 15, 2020!
Students will be on safari in Kruger National Park
Open to ALL majors GPA 2.5 or higher, in good standing Interest in Africa & Conservation previously taken GEA3600: Geography of Africa (recommended)
Email Dr. Jane Southworth for more information

Where Are they now?
Our recent grads have found themselves in some interesting places!
Dr. Roberta Mendonca de Carvalho, class of 2019, now teaches and researches at the University of Pittsburgh!


Come find out about the University of Florida in South Africa program  at the Study Abroad Fair on Wednesday, January 29 from 10 AM to 3 PM at the Reitz Union North Lawn.

We will also be hosting an informational session on our University of Florida in South Africa program on Wednesday, February 5th from 5-6 PM in Turlington Hall 3018.

University of Florida in South Africa
Summer A: May 26th – June 20th
Students will be in the field on safari in one of Africa’s prime wildlife areas! Imagine earning 6 credits while also gaining an understanding of the challenges, complexities and beauty of National Parks in South Africa. A truly incredible experience!
The program will primarily take place in Kruger National Park where students will go on safari, conduct reserve walks with Rangers, visit animal rescue facilities, and much more! Housing, lodging and food are all included.
Eligibility Requirements:
-Open to ALL majors
-GPA 2.5 or higher; student must be in good standing
-Interest in Africa & Conservation
-Previously taken GEA 3600: Geography of Africa (recommended but not required)
-Email the program director, Dr. Jane Southworth, to meet & discuss further trip details >>

APPLICATION DEADLINE: February 15th, 2020

Spaces are limited to only 14, and fill quickly!
Apply online at:

Image courtesy Dr. Olivier Walther

WALTHERCommerce de réexportation des textiles et villes frontalières entre Niger et Nigéria

Olivier J. Walther et Moustapha Koné

Article first published online: 01 JAN 2020 Les Cahiers d’Outre-Mer

DOI: 10.4000/com.9487

ABSTRACT: L’objectif de cet article est d’examiner les conditions économiques qui ont rendu possible le développement du commerce de réexportation aux frontières du Niger. Une analyse empirique des réseaux marchands organisés autour du textile d’occasion au sud du pays montre que l’émergence du commerce de réexportation repose sur la proximité de la région au port de Cotonou, des conditions fiscales attrayantes, et l’existence d’une diaspora marchande disposant du capital et de l’expérience suffisante pour mettre à profit la situation frontalière des marchés. L’article montre que les marchands du commerce de réexportation se sont installés au cours de trois grandes vagues de migration dont les origines géographiques sont toujours plus lointaines. Depuis l’élection du Président Buhari au Nigéria, l’essor de ce commerce de réexportation est toutefois remis en cause par des contrôles renforcés visant à limiter l’importation de produits frappés d’interdiction.

Read the full publication at Les Cahiers d’Outre-Mer.