An Atlas of African Cities


West Africa is urbanizing at one of the fastest rates in the world. Between 2015 and 2040, the population of the region will double and cities will absorb most of this demographic growth.

To better understand urban growth in West Africa, the UF Sahel Research Group will contribute towards the flagship report “Atlas on Cities in Africa” published by the OECD Sahel and West Africa Club in 2020.

The main objective of the Atlas is to analyze urban transformations and integrate their economic, social and territorial impacts into public policies and the development agenda.

This project builds on the Atlas of the Sahara-Sahel (2014), on our recent work on West African border cities and on the Africapolis database on urbanization in Africa recently released by the OECD.

Foreign interventions and networks of violence in the Sahel

africacheering-1031743-300x200 (1)

From 2019-2020, I will be coordinating the new research program on political insecurity of the OECD in collaboration with my colleagues Steve Radil and David Russell.

In this new project, our first goal is to develop reliable data on the spatial patterns and social networks of violent extremist organizations in the Sahara-Sahel from the late 1990s to today and at the smallest possible geographic and temporal scale for analysis.

We’ll look at three conflicts in which the relationships between the belligerents are often characterized by complex sets of alliances and conflicts that change over time: the civil war in Mali, the Boko Haram insurrection around Lake Chad, and the civil war in Libya.

We’ll then examine the effect of foreign interventions on the networks of alliances or conflict between violent extremist organizations in the region. we are particularly interested in testing whether foreign interventions lead armed groups to align with the side they believe has the highest chance of winning the conflict or whether they reinforce internal divisions within groups.

We also want to study how should foreign powers choose between competing groups in conflict. Which intervention strategy is more likely to promote cooperation between warring parties while also reducing conflict?

AAG 2019 – Space and social networks


Call for papers: American Association of Geographers Annual Meeting, Washington D.C., 3-7 April, 2019

Session title: Space and social networks

Organizers: Steven Radil, University of Idaho; Olivier Walther, University of Florida

Session description: The spatial metaphor of the network along with its accompanying abstractions, such as flow, movement, and connectivity, have been central themes throughout the relational turn in human geography. However, to date networks in geography have been primarily explored either through actor-network theory or assemblage thinking, both of which embrace the network metaphor without specifically and formally interrogating networks themselves. The session seeks to problematize the treatment of networks in geography by exploring the largely underutilized literature on social networks as an alternative to other relational frameworks. Our session invites papers that explore the conceptual connections between core geographic concepts, such as place, distance, scale, territory, and power, and social networks. We are particularly interested in papers that open new directions for geographers that are interested in more than the metaphor of the network.

We envision a session that explores themes such as:

  • Geographic approaches to social network analysis
  • Networks of places and/or places as networks
  • Spatial proximity and networks
  • Cross-border networks
  • Geographic variation in social networks
  • Networks and scale
  • Power and networks

We invite papers on these or related topics. Please send proposed titles and abstracts (250 words or less) and/or expressions of interest to both Steven Radil (sradil (at) and Olivier Walther (owalther (at) no later than 31 October, 2018.

Why so many rebel groups in Syria?

ooIn Syria, hundreds of factions operate under dozens of separate organizational command structures. Rather than coalescing into a unified rebel front, rebel groups continue to compete for power, thus failing to develop structures of governance and political authority that cut across factional divides, enclaves and provincial boundaries.

Despite the fact that inter-rebel violence is a common phenomenon, the mechanisms causing fragmentation and infighting within rebel movements remain poorly understood. In a new working paper posted today on SSRN, my former graduate student Patrick Steen Pedersen, who now works at the Royal Danish Defence College, and I discuss what has caused the Syrian rebel movement to fragment from 2011 to 2017.

Building on Bakke et al.’s study who suggests that divisions within rebel movements can be explained by examining how numerous, institutionalized and powerful are the organizations within a conflict, we divide the conflict into four different phases and discuss the development of various patterns of fragmentation throughout the conflict.

Our study reveals that the causal mechanisms of rebel fragmentation in Syria are both endogenous and exogenous. The circumscribed state of the pre-war political opposition, the absence of independent institutions and the state’s co-optation of Syria’s civil society organizations severely thwarted the way in which the widespread discontent with the Syrian regime could manifest itself at the onset of the conflict.

Exogenous factors also played a key role, particularly the lack of donor coordination, intra-regional competition and reorientation of patron policies.

Applying Social Network Analysis to terrorist financing


Illicit financial networks are, by their very nature, difficult to detect and, therefore, difficult to study. Much of the information on individuals and their activities is either classified or unknown. Nonetheless, tracking how terrorists raise, move, store and use money is fundamental to deter and discourage terrorist networks.

In a new chapter published in the Handbook of Criminal and Terrorism Financing Law, my colleague Christian Leuprecht and I posit network science as a method to improve our understanding of the way terrorists, criminals and their facilitators exploit the global marketplace

Drawing on evidence from select Hezbollah and Al-Shabaab financing networks, we argue that the application of Social Network Analysis (SNA) to the study of terrorist financing and money laundering advances the current state of knowledge in this notoriously difficult-to-study field.

Our study shows a network’s structure matters because it dictates the flow of resources and information. The Hezbollah and Al-Shabaab networks display the characteristics associated with fundraising networks: hub structure, brokers with high betweenness centrality and low degree centrality, international linkages, no intent to commit domestic attacks, and remittances to the home country.

Knowing that fundraising networks will conform to this structure gives policy makers and law enforcement important tactics to deter and discourage their activities. Fundraising networks are vulnerable at the hub, but resilient against traditional counter-terror measures that target hierarchies. They tend to compensate for the relative vulnerability of their structure by relying on strong ties with pre-existing acquaintances.

Instead of operating as hierarchical organizations, with orders flowing from a figure at the head down through the network, this article reinforces the view that terror networks should be conceived for what they are and how they work, and not solely according to their formal structure.

While the political party and semi-governmental organization of Hezbollah in Lebanon may follow a more hierarchical organizational structure, illicit networks supported by Hezbollah in North America are able to maintain their secretive and stealthy nature precisely by adopting a more informal and flexible structure.

Regional integration in Africa


More than 50 years have passed since the Organisation of African Unity (OAU) was created in Addis Ababa on 25 May 1963. Yet, despite the many charters signed, the numerous meetings called, and the countless strategic frameworks drawn up on paper, regional integration has led to disappointing outcomes.

In the newly published Routledge Handbook of African Development edited by Tony Binns, Kenneth Lynch and Etienne Nel, I discuss the many factors that explain why progress made towards effective regional integration has been slow on the continent.

The chapter focuses particularly on the gap between regional integration as an institutional project (also known as regionalism) and regional integration as an everyday reality (regionalisation).

Generally speaking, regional integration in Africa has achieved the highest objectives when institutions have targeted very specific areas, such as the environment, have been heavily supported by external donors and member states, and have brought together countries that share a similar currency, such as the CFA franc.

Progress toward regional integration in Africa has been slow for several reasons. In a patrimonial system that nurtures inter-personal relations, many countries have few incentives to effectively engage in deeper institutional integration with their neighbors.

Regional integration also has a disappointing record due to the large number of organisations that exist with similar or competing purposes. Nearly all African states belong to multiple regional groupings, which lead to high co-ordination costs, competition between policies, and confusion among international donors.

Finally, regional integration has been greatly affected by political crises and conflicts, as in the Great Lakes region or the Horn.

Mapping rice trade networks


Women play a key role in West Africa’s food economy. Yet, the functioning of their trade networks is still relatively unknown. To better understand how women do business in the region and what obstacles they face, the OECD Sahel and West Africa Club asked us to map the network that connects the actors involved in the production, transport or sale of locally-produced rice between Benin, Niger and Nigeria.

Our data were collected in the Dendi border region by our colleagues Dr. Lawali Dambo, Dr. Moustapha Koné and their team at the University of Niamey. It took more than three months to interview 800 producers, traders and wholesalers in three countries. Two more months were needed to structure the data and produce what is probably one of the largest supply chain networks ever mapped in West Africa! In the next few months, we’ll analyze the data in order to highlight gender disparities and border effects.

Enduring divisions within border studies


In recent years, large-scale research programs, such as BIG or AFRIGOS, have been launched in different parts of the world to examine border conflicts, cross-border cooperation, regional trade, or transnational migration. We, border scholars, travel more, meet more people at exciting conferences, and submit more proposals. But when it comes to publishing, we still write alone. In our own country.

This phenomenon is of course not happening only in border studies. In a recent paper, Cerina et al. (2014) show for example that connectivity between scientists decays exponentially in Europe due to the existence of national communities of inventors, and as a power of distance in the borderless market of the United States. Internal divisions within border studies are however no small paradox for a science supposedly cross-border by nature. They also have been relatively little studied to date.

Less than half of the papers published in the Journal of Borderlands Studies (JBS), our flagship journal, have one or more coauthors. And this has not really changed over the last decade. Actually, the peak in co-authorship was reached more than 15 years ago, as can be seen from the graph below.

Co-authored papers published in JBS, in percent, 1986-2015


Source: Olivier Walther (2016) based on JBS’s website.

Because JBS is the primary publication of the Association of Borderlands Studies (ABS), founded in 1976 to study the United States-Mexico borderlands, US border scholars have enjoyed a dominant position in the journal. More than half of the papers ever co-published in JBS have been written by scholars affiliated with a United States institution. As can be seen below, those affiliated with a German, Mexican or Dutch institution each represent around 5% of the papers co-published since its creation.

Proportion of co-authors by country, in percent, 1986-2015


Source: Olivier Walther (2016) based on JBS’s website.

The first paper co-authored by a non-US scholar was published by Joan Anderson of the University of San Diego and Martin de la Rosa of the National Autonomous University of Mexico in 1991. It took JBS four more years to publish a paper whose co-authors were not affiliated with a North American institution.

Another way to look at how integrated border scholars are is to map who has published with whom in JBS since the creation of the journal in 1986. The sociogram below clearly shows how fragmented our community is when it comes to co-publishing. Instead of a fully integrated community, we form a fragmented network building on lots of dyads and triads. Despite the current internationalization of border studies, the main components of the network are still located in the United States (in red), and, secondarily, in Germany, Mexico, the Netherlands, and Canada.

Co-authorship in JBS by nationality, 1986-2015


Source: Olivier Walther (2016) based on JBS’s website.

Not only do we often publish alone: we also predominantly publish within our own country. Cross-border co-authored papers are the exception in our field, as can be seen from the sociogram below, in which only the papers published by two or more authors located in different countries have been represented.

Cross-border co-authorship in JBS by nationality, 1986-2015


Source: Olivier Walther (2016) based on JBS’s website.

Academic genealogy

paul vidal de la blache

My interest in West African cities owes much to the fact that I received a joint PhD in geography from the University of Lausanne and the University of Rouen .

In Lausanne, my supervisor was Professor Jean-Bernard Racine, one of the pioneers of the New Geography in the 1970s, and a recipient of the Vautrin Lud Prize, the highest award in geography, for his work in economic and urban geography. In Rouen, I studied under the supervision of Professor Denis Retaillé, one of the world’s leading scholars on the Sahel, whose work on space and networks continues to exert an enormous influence on my research

The academic genealogy of my supervisors reveals fascinating intellectual connections: both Racine and Retaillé are actually indirectly connected to Paul Vidal de la Blache (1845-1918), the most influential French geographer of the 19th century (see picture above).

Professor Racine received his PhDs from the University of Aix-en-Provence (1965) and Nice (1973). While in North America, Racine was profoundly influenced by Walter Isard, the founder of regional science, and by geographers Brian Berry, Stanley Gregory, Bryn Greer-Wooten, David Harvey and Peter Gould, whose model of transport development was based on Ghana and Nigeria. In France, Sorbonne University professors Pierre George and Paul Claval had a strong influence on Racine’s thinking.

Racine’s PhD thesis was supervised by Professor Hildebert Isnard, whose early work dealt with North Africa, Madagascar and Reunion and who worked under the supervision of Professor Robert Capot-Rey of the University of Algiers. Capot-Rey, a one-leg professor who explored the erg of Murzuk and much of the Sahara, is the author of Le Sahara Français, a monumental volume published in 1953. Capot-Rey was himself a student of Lucien Louis Gallois, a Sorbonne professor who worked closely with Paul Vidal de la Blache on Les Annales de Géographie, an influential journal founded in 1891, and on de la Blache’s Géographie Universelle.

Professor Retaillé received his PhD from the University of Paris in 1983. His supervisor was Professor Jean Gallais, who discovered Africa in the early 1950s and became the leading specialist of the Inner Niger Delta in Mali. Gallais was himself a student of Professor Pierre Gourou, a major proponent of French tropical geography. Gourou studied with Albert Demangeon, a Sorbonne University professor who pioneered the use of surveys in geography and was a student of Vidal de la Blache.

Pathways via doctoral supervisors

— Paul Vidal de la Blache (1872) — Lucien Louis Gallois (1890) — Robert Capot-Rey (1934) — Hildebert Isnard (1947) — Jean-Bernard Racine (1973) — me (2006)

— Paul Vidal de la Blache (1872) — Albert Demangeon (1905) — Pierre Gourou (1936) — Jean Gallais (1967) — Denis Retaillé (1983) — me (2006)

New report on women’s empowerment in West Africa


In a report published by the World Food Programme today, my colleagues Leena Hoffmann, Paul Melly and I highlight some of the constraints that tend to limit the scope for women to achieve higher incomes from a more diverse and sustainable range of agriculture-related activities in West Africa.

Building on a comparative study of the Kano-Katsina region in northern Nigeria and the Maradi region in southern Niger, our report explores the rural and commercial setting in which women conduct their routine affairs and considers social, legal, regulatory and financial factors that influence women’s chances.

The study contributes to a better understanding and assessment of the links between gender and the functioning of markets and value chains under relatively stable conditions. It is part of the Vulnerability Analysis and Mapping (VAM) Gender & Markets Initiative of the World Food Programme Regional Bureau for West and Central Africa in Dakar.