Ecology in a troubled continent

Ecology is a global science that examines various levels of biological organisation (organism, species, population, community, guild, trophic level, etc) and spatial dimensions of biological–physical interactions (habitat, niche, ecosystem, biome, biosphere). Importantly, ecological science focuses on identifying recurring patterns in animal and plant communities worldwide (Kingsland, 1991). Ecologists typically invest a lot of time in reading articles developed in various ecological situations and in different continents to update their investigation methods and advance their own case studies and ultimately provide context for discussing general ecological theories. Ecology has evolved into an inclusive discipline that integrates findings from various scientific fields, including physics, chemistry, and mathematics. Its research outcomes are disseminated in numerous scientific journals globally. This interdisciplinary approach demonstrates the close interconnection between ecology and the “hard sciences.” Moreover, ecology is continuously expanding its scope by embracing a wide range of topics and methodologies, fostering a global integration of knowledge within the field. Notwithstanding the extensive integration of ecological research that currently occurs on a global scale, it is undeniable that distinct “environmental opportunities” (EOs) exist. These EOs, here defined as the ensemble of climate, vegetation, biogeography, animal adaptations, species richness, social and cultural aspects of human communities, history, economy, etc., that characterises each of the world's region have shaped the development of regionally specific “ecological hot topics.” These various research topics often converge towards specific recurrent themes that are common to the various regions of the world. For instance, the observation of regular inter-annual fluctuations (“cycles”) in rodent populations observed under harsh climates in Scandinavian and Canadian regions stimulated very detailed population dynamics studies (e.g., Andreassen et al., 2021; Korpela et al., 2013) that generated a sophisticated perspective of the oscillations in populations of their predators (e.g., Hanski et al., 1991; Korpimäki et al., 2002). Animal population dynamics have not received the same attention in the Mediterranean and perhaps less so in tropical regions where rodent populations do not fluctuate cyclically and have far less predictable abundances (e.g., Amori et al., 2015; Casula et al., 2019). Furthermore, the significance of nutrient enrichment assessment, which has traditionally played a dominant role in ecological studies conducted in temperate inland waters (e.g., Beklioğlu et al., 2020; Tagliaferro et al., 2022), diminishes in tropical settings where algal growth occurs consistently throughout the year without a distinct period of nutrient accumulation. Conversely, extensive and deep Afrotropical lakes have provided unparalleled insights into patterns of freshwater fish speciation when compared to other regions of the world (e.g., Seehausen et al., 2008; Wagner et al., 2014). Moreover, methodologies employed in the study of ecological phenomena can vary based on local EOs. For example, while the marking of individuals remains the primary method used in studying reptile populations in temperate regions of Europe, North America, and Japan (e.g., Madsen et al., 2020; Madsen, Loman, et al., 2023; Madsen, Ujvari, et al., 2023), this technique is seldom applied in tropical regions due to the greater elusiveness and unpredictability of individuals since they are less reliant on thermoregulation and consequently spend less time above-ground than their temperate counterparts (Anderson et al., 2005; Bovo et al., 2012; Luiselli & Akani, 2002). To put it differently, the unique EOs found in specific regions present challenges to scientists, shaping their research questions and influencing the methodologies they employ to investigate ecological phenomena. As a result, distinctive “thematic niches” have emerged in ecological research across continents and regions due to the influence of these EOs. This is evident in the extensive collection of articles published in the African Journal of Ecology (AJE) over the past decades, which reflect the evolution of thematic niches within African ecology. These niches distinguish African ecological studies in an original manner from research conducted in other continents. What fields of study contributed most to the originality of African ecological science in recent decades? Three main themes come to mind: (i) the study of large mammals (herbivores and their predators) in savannahs, (ii) the bushmeat issue, and (iii) forest conservation highlighting the role of local communities (the latter two themes have also been studied in other continents, but not to the same intensity as in Africa). The AJE has extensively covered these themes, as evidenced by numerous recent contributions focusing on savannah mammals. (e.g., Ang'ila et al., 2023; Ayechew et al., 2022; Everatt et al., 2023; Lee et al., 2023; Tarugara & Clegg, 2022; Tiller et al., 2022), bushmeat (e.g., Djagoun et al., 2022; Froese et al., 2022; Hariohay et al., 2022; Hart et al., 2022; Sonhaye-Ouyé et al., 2022), and community forests (e.g. Fa & Luiselli, 2023; Mavah et al., 2022; Oyda et al., 2022; Poulain et al., 2023; Rampheri et al., 2022). The field of ecology is constantly evolving, and the separation of “thematic niches” based on local EOs is an ongoing process worldwide. As this niche separation continues, new emerging themes are also taking shape, influenced by the ever-changing local EOs in different geographic regions. In the context of Africa, it is crucial to identify the new emerging niches of ecological research and determine which research questions will be of significant relevance for the AJE in the coming years. While providing a comprehensive answer to these questions is challenging, there are indeed emerging research topics that appear to be particularly significant and promising. One emerging niche in African ecological research pertains to the study of ecosystems in the context of conflicts and mass migrations. Africa has experienced numerous conflicts and refugee crises, leading to significant environmental and ecological impacts. The presence of refugees in host countries, particularly in environmentally fragile areas, has resulted in habitat fragmentation, deforestation, overhunting, and overfishing. These issues pose a significant challenge to conservation planning and require (i) ecological analyses to assess their effects on wildlife populations and overall ecosystem health and (ii) appropriate management actions (Battisti, 2023). The recent humanitarian emergencies that are the result of political tensions for control over Sudan have produced streams of refugees fleeing to the neighbouring countries. Many have sought temporary resettlement around cities but also in the open landscape where they directly impact the natural environment. For over 70 years, the African continent has been the setting for most of the world's conflicts that have included devastating civil wars such as those that led to the Genocide in Rwanda (1994); no doubt the most brutal to date and infamous. Given the high number of conflicts that has taken place between 1953 and 2023, it is not surprising that the largest number of refugees in the world (about 34% of the world's total for this period) is found in Africa. According to the most recent estimates, of 26.3 million refugees worldwide, 72% originate from only five countries, of which South Sudan has about 2.4 million (https://www.unhcr.org/refugee-statistics/; last accessed on 20th March 2023). As many as 36% of the world's total number of refugees have settled in just five countries, one of them being African (Uganda, which currently hosts 1.5 million refugees; https://www.unhcr.org/refugee-statistics/; last accessed on 20th March 2023). Least developed countries provide asylum to 22% of the total; the density of refugees is highest in areas that are likely the environmentally most fragile, (https://www.unhcr.org/refugee-statistics/; last accessed on 20th March 2023). In Africa, the largest refugee settlements are in the North West Uganda (Aka West Nile region): Yumbe (223,300), Adjumani (202,500), Arua/Koboko (160,200), Moyo (119,000), Kyriandongo (55,500), Lamwo (36,800) (source: https://www.unhcr.org). Refugee-hosting areas undergo massive agricultural expansion and habitat loss (e.g., see Barasa et al., 2020; Maystadt et al., 2020; Figure 1). The impact of refugees has emerged as a significant threat that hinders conservation planning efforts across much of Africa (Luiselli, 2023a, 2023b). Addressing issues such as habitat fragmentation, deforestation, charcoal burning, overhunting, and overfishing requires ecological analyses (Luiselli, 2023b). Several studies have indicated that conflicts and subsequent refugee migrations can lead to contrasting patterns in wildlife populations, namely the “war-zone/game source” phenomenon (Dudley et al., 2002; Martin & Szuter, 1999) and “wildlife impoverishment” (Gaynor et al., 2016). The “war-zone/game source” pattern has been observed in areas of the Democratic Republic of Congo, where civil war and refugee invasions severely impacted elephants in protected areas (Hall et al., 1997; Hart & Hall, 1996), and in Rwanda, where mountain gorillas and ungulates declined due to large-scale poaching and refugee migrations (Plumptre et al., 1997). On the other hand, “wildlife impoverishment” is characterised by the loss of specialised species and an overall reduction in species richness at the local level. This pattern often occurs when refugees concentrate in sparsely populated areas, frequently encroaching upon protected areas. For example, in Nigeria, this phenomenon has been observed in Chad Basin National Park, Kamuku National Park, and Kainji Lake National Park. The extent of wildlife impoverishment can become extreme when large numbers of displaced people are involved. In Rwanda, during the civil war, approximately 50% of the country's civilian population (around 3.5 million people) was displaced into camps in the eastern regions of the Republic of Congo. About 860,000 refugees were concentrated near Virunga National Park, and 332,000 were encamped near Kahuzi Biega National Park (Prunier, 1995). Unfortunately, our understanding of the long-lasting impact of these refugee situations on ecosystems is severely limited due to the scarcity of published evidence. There is a significant knowledge gap in this regard, and further research is needed to assess the extent of the ecological consequences of refugee migrations in these regions. In the years to come, it is crucial to investigate the impacts of refugee displacement and new settlements on species extinction and other ecological effects. While iconic megafauna such as ungulates, elephants, and gorillas often receive attention, there is a multitude of overlooked animal and plant populations that have been severely affected and require re-evaluation of their distribution. In North West Uganda, there are two “least charismatic” species facing serious threats from refugee activities. The Nubian flapshell turtle (Cyclanorbis elegans), for instance, is on the brink of extinction due to overfishing (Demaya et al., 2019; Luiselli et al., 2022), and its future survival is seriously threatened by the fact that refugees demand for meat and this large turtle may be a target for their fishers (Demaya et al., 2023). Additionally, the recently described endemic scarab beetle species, Fornasinius hermes, is experiencing severe habitat loss and degradation caused by the rapid growth of new human settlements (L. Luiselli, G. S. Demaya, and M. Behangana, unpublished observations, 2023). Unless the processes threatening these species are addressed promptly, these species and possibly many others may face extinction within a few years. Additional scenarios warrant investigation concerning their ecological ramifications, such as the effects instigated by terrorists, private armies, or even warfare itself (Braga-Pereira et al., 2022; Braga-Pereira, Bogoni, & Alves, 2020; Braga-Pereira, Peres, et al., 2020). For example, the Angolan civil war brought about changes in hunting practices, even in remote regions, due to the widespread availability of automatic weapons provided to combat militias and their supporters. This shift directly contributed to a rapid decline in mammal diversity (Braga-Pereira, Bogoni, & Alves, 2020), resulting in their near-total eradication (with reductions of up to 80% from pre-war population levels; Braga-Pereira, Bogoni, & Alves, 2020; Braga-Pereira, Peres, et al., 2020). The ecological and life-history characteristics of species and habitats seemingly influenced the manner in which various target species experienced this decline: according to Braga-Pereira, Peres, et al. (2020), (i) the post-war abundance of 77% of mammal species was lower in open savannah compared to closed-canopy forest environments; (ii) larger mammals were preferentially targeted and subjected to overhunting; (iii) as the population sizes of larger species dwindled, the size structure of targeted mammal species gradually shifted towards smaller-bodied taxa. An intriguing avenue for further investigation involves examining the patterns of environmental protection afforded by local communities before, during, and after conflicts. Recent research has revealed that indigenous lands can safeguard nature even amidst areas of armed conflict (Beattie et al., 2023). Notably, Beattie et al. (2023) found that while armed conflict was more likely to occur on indigenous peoples' lands within biodiversity hotspots than on other territories, the resulting environmental damage and anthropogenic impacts were comparatively lower. The most remarkable conclusion drawn from Beattie et al.'s (2023) study is that Indigenous Peoples managed to mitigate ecosystem degradation to some extent prior to, during, and after armed conflicts due to their deep connection to their lands and their resolute commitment to defend their rights and territories. This intriguing hypothesis warrants further exploration through additional case studies to facilitate broader generalisations. Undoubtedly, it represents an enticing prospect for future research in the field of African ecology and conservation. The tragic mass displacement of African populations brings forth a new and urgent task for ecological research, particularly relevant to the African context. A key theme for future investigations should be to understand how human pressure rapidly alters community diversity patterns. While epochal changes typically occur over long periods, the establishment of large refugee settlements can create transformative impacts within a remarkably short timeframe (few years instead of hundreds or even thousands of years). Another crucial question that requires in-depth exploration is the identification of factors and dynamics that contribute to either the “war zone/game source” pattern or the “wildlife impoverishment” paradigm. Gaining detailed ecological knowledge of these mechanisms is essential to inform effective conservation strategies during periods of large-scale conflicts and refugee migrations. However, it is important to note that the AJE has made limited contributions to this important field of research. In fact, a thorough search of the journal's database on 4 June 2023, revealed only few articles on the subject (Braga-Pereira et al., 2022; Hall et al., 1997). At the same time, some recent university dissertations at the master's and doctoral levels have addressed these pressing issues, submitted to African universities (e.g., Isabirye, 2021; Masete, 2020). This editorial serves as an encouragement to these young researchers to continue their valuable work and to develop high-quality manuscripts on these subjects for submission to AJE in the coming years. Such research is of utmost importance for our journal and for fostering a new scientific focus on a continental scale. This article has been improved through constructive discussions with Prof. Julia E. Fa (Manchester Metropolitan University, U.K.) and Dr Nic Pacini (University of Calabria, Italy).

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