Cameroon-Nigeria Border Research Articles

Molecular epidemiology of recurrent zoonotic transmission of mpox virus in West Africa.

Nigeria and Cameroon reported their first mpox cases in over three decades in 2017 and 2018 respectively. The outbreak in Nigeria is recognised as an ongoing human epidemic. However, owing to sparse surveillance and genomic data, it is not known whether the increase in cases in Cameroon is driven by zoonotic or sustained human transmission. Notably, the frequency of zoonotic transmission remains unknown in both Cameroon and Nigeria. To address these uncertainties, we investigated the zoonotic transmission dynamics of the mpox virus (MPXV) in Cameroon and Nigeria, with a particular focus on the border regions. We show that in these regions mpox cases are still driven by zoonotic transmission of a newly identified Clade IIb.1. We identify two distinct zoonotic lineages that circulate across the Nigeria-Cameroon border, with evidence of recent and historic cross border dissemination. Our findings support that the complex cross-border forest ecosystems likely hosts shared animal populations that drive cross-border viral spread, which is likely where extant Clade IIb originated. We identify that the closest zoonotic outgroup to the human epidemic circulated in southern Nigeria in October 2013. We also show that the zoonotic precursor lineage circulated in an animal population in southern Nigeria for more than 45 years. This supports findings that southern Nigeria was the origin of the human epidemic. Our study highlights the ongoing MPXV zoonotic transmission in Cameroon and Nigeria, underscoring the continuous risk of MPXV (re)emergence.

Viruses associated with cassava mosaic disease and their alternative hosts along Nigeria-Cameroon border

Cassava mosaic disease (CMD) threatens cassava production across the African continent. Because CMD is widespread in sub-Saharan Africa (SSA), it is particularly important to monitor border regions to prevent the introduction of other cassava (Manihot esculenta Crantz) viruses and strains into regions otherwise considered still free of the viruses. The objective of this study was to establish the occurrence of viruses associated with CMD and their alternate host plants along the Nigeria-Cameroon border. One hundred leaf samples from cassava plants and weed species were collected across 21 locations, along the border regions of Cross River State; and assessed for CMD incidence and severity. Nucleic acid extracts were obtained and used to test for African cassava mosaic virus (ACMV) and East African cassava mosaic virus (EACMV), using polymerase chain reactions. Plants from ten, seven and four locations had mild, moderate and severe CMD symptoms, respectively. Of the 100 samples collected, 68 were symptomatic and 32 were asymptomatic for CMD; while five weed species were symptomatic. ACMV alone was detected in six symptomatic and three asymptomatic cassava leaves. EACMV was singly detected in one symptomatic and two asymptomatic cassava leaves; while 13 cassava leaves from ten locations had mixed ACMV/EACMV infections. One asymptomatic cassava leaf from Ikang tested positive for ACMV and EACMV. EACMV alone was detected on a symptomatic weed species, Sclerocarpus africanus. The occurrence of viruses causing CMD in Nigeria, including the border regions, has now been further documented, and S. africanus is now verified as a host of EACMV. There is a need for further studies on other plants that may be putative reservoirs for cassava mosaic viruses, towards the development of integrated management strategies.

Cameroon-Nigeria Border Conflict Prevention and Resolution Over the Bakassi Peninsula, 1884 – 2008: Model for Peacebuilding in Africa

Purpose: Relations between Nigeria and Cameroon have been strained for a number of years due to conflicts over the ownership and administration of the resource-rich Bakassi Peninsula. After independence, Cameroon and Nigeria accepted the colonial borders, but Nigerian authorities decided in 1980 to question these borders. Following several failed diplomatic attempts to prevent and resolve the conflict, Cameroon approached the International Court of Justice (ICJ) at the Hague with a petition on March 29, 1994 and at the end of the process which lasted eight years, the ICJ rendered its final verdict on October 10, 2002 in favour of Cameroon. This study seeks to examine the geopolitics and historical context of the Bakassi dispute. It argues that, the different conflict prevention measures adopted through the creation of the Joint Cameroon–Nigeria Border Commission in 1965; Yaounde I Declaration of August 14, 1970; Yaounde II Declaration of April 4, 1971; Kano Declaration of September 1, 1974; Maroua Declaration of June 1, 1975; and the activities of the Cameroon-Nigeria Mixed Commission from 2002 to 2007 provided a model for dialogue and mediation in the prevention of armed conflicts in Africa.
 Methodology: The study utilized primary and secondary sources to investigate the measures adopted in preventing the conflict and to ascertain that the methods of conflict resolution such as mediation, bilateral negotiation, facilitation, adjudication, agreement and dialogue applied were very successful.
 Findings: The study concludes that, addressing the shortcomings of conflict prevention and resolution mechanisms could improve stability, guarantee security and maintain peace. The study recommends that, governments, the general public, litigants, mediators and policymakers involved in the prevention and resolution of border conflicts should be educated and trained on alternative dispute resolution processes in Africa.
 Unique Contribution to Theory, Policy and Practice: This study contributes to theory, policy and practice in the sense that, conflict prevention through dialogue, creation of joint and mixed commissions, and the arrival of consensus through declarations and agreements have significant potentials for handling and resolving the growing number of armed border conflicts in Africa.

Potential impact of climate change on the distribution of some selected legumes in Cameroon and adjoining Nigeria border

AbstractOrganismal response to climate change may affect long‐term conservation plans. However, how climate change affects the distribution and conservation status of some plant species is still being debated. To test this, we selected four economically important legume species (Adenocarpus mannii, Afzelia bella, Afzelia bipindensis and Baphia nitida) from the Nigeria–Cameroon border in West Africa. The link between climate change and the species distribution range was predicted using the ensemble species distribution model (ESDM). Our analyses revealed the precipitation of the coldest period (50%) and precipitation of the driest period (40%) as the most important environmental variables influencing the distribution of the studied species. The projection shows independent habitat shifts (gain/loss) of the species consequent to climate change in the future (2050 and 2070). Despite the restricted coverage of occupancy for the selected species, our estimated species distribution range from the ESDM agrees with the current IUCN conservation status (least concern) for A. mannii. Hence, our results suggest that species distribution modelling at local habitats could yield insights into global species conservation assessments. Our findings highlighted the need for conservation through regulated land use in Dibombari highland, Cameroon Mountain (Cameroon) and the forests around Oban hills in Nigeria due to projected high species loss consequent to climate change. Thus, we recommend ecological niche modelling with extensive field surveys across the entire geographic range of these species for robust inferences that allow comparisons with the IUCN status.

Ethnic groups across Nigeria–Cameroon border territories: contested autochthony and contentious ethnic identities in Mambilla Plateau, Nigeria

ABSTRACT While extant literature has examined how autochthony claim-making and narratives account for violent conflicts, they neglect how ethnic groups traversed by Nigeria–Cameroon boundaries manipulate autochthony claim-making and generate ethnic identity crises in the Mambilla Plateau. Using the qualitative dominant mixed-method approach, this paper describes the various ways in which people have come to understand themselves and deploy the autochthony narratives to construct group identities in the Mambilla Plateau. It also examines how the couching of these autochthony narratives and their politicization reinforce contested territorial ethnic claims and generate ethnic identity crises in the region. Relying on social identity thesis, the study argues that extreme ethnic in-group and out-group divides undermine peaceful coexistence of ethnic groups, drive identity crisis as well as fuels ethnic hostilities and population displacements in the Mambilla Plateau. The study concludes that nuanced and inclusive autochthony claim-making presents an opportunity for reducing inter-ethnic hostilities and promoting the peaceful coexistence of ethnic groups in the Mambilla Plateau and other multi-ethnic societies in Africa.

PROBLEMS ASSOCIATED WITH CROSS-BORDER PATIENT MOBILITY AND UTILIZATION OF HEALTHCARE FACILITIES ON THE NIGERIA-CAMEROON BORDER, BAMA LOCAL GOVERNMENT AREA, BORNO STATE

This research was carried out retrospectively on the Nigerian – Cameroon border. There are so many communities that live on this border. It was stated in the Border Community Development Agency Act (2003) that Bama Local Government area has 120 identified border communities. These populations therefore need to have access to healthcare facilities on either side of the boundary as they interact in different ways, which expose them to infections, contagious and other socially transmittable diseases. Cross-border healthcare access is therefore relevant to people living on the border. This study examines the extent of cross-border patient mobility and healthcare utilization in the three districts (Banki, Dare-el-jamal and Kumshe) on the Nigeria-Cameroon border. The researchers used mix methods research design. Survey was conducted supplemented by qualitative method which enables the researchers to obtain both quantitative and qualitative data. The researchers and two trained research assistants went to the two camps that host internally displaced persons (IDPs) from Bama local government area (Dalori camp I and II) and identified 625 cross-border patients that come from Banki, Dare-el-jamal and Kumshe districts. This served as the sample population for the research and 40% of the population was selected as sample respondents by random sampling technique. Descriptive statistical tools were used to interpret the data acquired i.e percentages and Chi-square at P≤0.05 was used to test whether cross-border healthcare utilization in the study area was gender sensitive. Distance decay curves were also used to measure the impact of distance on the level of patronage of healthcare facilities across the Nigeria-Cameroon border. The study revealed that there were established health centres in the three districts but were poorly equipped and that more Nigerians patronize the healthcare facilities across the border where 65.5% of the respondents indicated that more Nigerians sought treatment in Cameroon.

First Report of the Larva of a Vulnerable Damselfly in Nigeria, With Some Ecological Notes: A Case for Umbrella Species Conservation Approach

Background and Research Lack of information on the distribution of threatened aquatic species impedes their conservation, thus predisposing them to extinction risk before being reported. Hence, this study reports in Nigeria, for the first time, the occurrence and habitat specificity of the larva of Pentaphlebia stahli (Zygoptera: Pentaphlebiidae) a vulnerable damselfly. Methods Samples of P. stahli were collected in July and December 2020 from a rural stream situated at the Ekor Waterfalls in the Cross River State of Nigeria and very close to the Nigeria–Cameroon border. Some water quality parameters were also measured in each sampling period. Results A total of 27 larvae of P. stahli and 1 teneral adult emerging from its exuvia were recorded in the two sampling periods. The habitat was a forested stream characterized by rapids, falls, and dark rock substrata. Water flows at a fast rate of 1 m in 3 or 4 seconds, thus characterizing a rifle and headwater stream. Dissolved oxygen concentration was between 8.05 and 8.09 mg/L, while dissolved oxygen saturation was ∼98%. Biological oxygen demand was between 1.04 and 1.08 mg/L, while pH ranged from 7.28 and 7.56. Conclusion The stream could be described as having high ecological integrity as evidenced in its optimum range of values for the investigated water parameters and the presence of a threatened species. Implications for Conservation Based on habitat specificity, P. stahli is considered an umbrella species required for conserving other co-occurring species in the tropical stream and its riparian forest.

Rethinking the Nature, Implications and Challenges of Informal Cross Border Trade by Women from Cameroon across the Cameroon-Nigeria Southwestern Borders

Women’s participation in informal cross border trade (ICBT) in Cameroon has progressively become a popular and vital safety net to unemployment. While it has been acknowledged that earnings from women’s ICBT activities contribute to reductions in poverty and women’s empowerment, scant evidence reports the patterns of ICBT carried out by women. This paper seeks to examine the activities of women cross-border traders along the Cameroon-Nigeria border. Using questionnaire and interview guide, the study examines how ICBT is effectively carried out, and the nature and trends of ICBT across the Cameroon-Nigerian border. Findings noted that women involved in ICBT between the Cameroon-Nigeria border are young between 21 - 40 years and married with large families. While the women involved come from diverse demographics and trade with assorted goods, they started off as informal traders with access to business capital through informal thrift channels. By and large, women are motivated into ICBT by capital constraint to start a formal business and the possibilities to make more profit due to tax evasion and smuggling. While women’s ICBT impacts on reductions in household poverty and women’s empowerment, these activities affect state custom revenue. A better policy framework that increases women’s profitability and protects state revenue by addressing custom and police corruption is indispensable for the sustainability of the economic impact of ICBT.

Boys Becoming Men. Male initiation rites in a North-Eastern Nigerian village

The Chadic-speaking Fali of the southern Mandara Mountains live in well-organised, compact villages of thousands on both sides of the Nigeria-Cameroon border. They are subsistence sorghum farmers whose communal and personal existence depends on having several children and a good annual harvest. Unsurprisingly, these two existential facts determine both the fundamental values and much of the daily life of the Fali. An examination of the biennial initiation cycle and its main rites also reveals that, at the ritual level, these manifest a symbolic equivalence to the developmental cycle of their staple crop, sorghum, and are attuned intime to the agricultural cycle. In my presentation at the IX. MΩMΟΣ conference (Miskolc, 2015) I described in detail, and showed pictures of the 2007 Fimbidi rite (Figs 6–13), the greatest of the initiation rituals of the Jilvu Fali. In this short paper I intend to overview the main characteristics of the whole of the Jilvu male initiation cycle, drawing attention to the complicated web of social relationships, underlying beliefs, personal and communal ambitions behind the rites. Although this picture cannot be but sketchy, I hope it will nonetheless be of interest to archaeologists.This presentation is derived from my husband’s, anthropologist James H. Wade’s early work among the Falifrom the 1970’s onwards, and our joint fieldwork from the 1990’s to 2010. The accompanying pictures, like those of my 2015 presentation, were taken by him.

Genetic Polymorphisms of Pfcrt K76T and Pfmdr1 N86Y among Asymptomatic School Children in Forest Communities of Ekondo Titi Subdivision along the Cameroon-Nigeria Border Area

Aims: The study sought to quantify Plasmodium infection and molecular markers for chloroquine resistance among asymptomatic school children.
 Study Design: The study was cross-sectional.
 Place and Duration of Study: The study was carried out in Ekondo Titi Subdivision near Cameroon's south-western border with Nigeria from March to May and from September to October 2014.
 Methodology: The prevalence of human Plasmodium species was determined by nested PCR (Polymerase Chain Reaction) using DNA from dried blood spot in six primary schools. A PCR/RFLP analysis (Restriction Fragment Length Polymorphism) was used to determine the prevalence of chloroquine resistance (CQR) associated pfcrt 76T and pfmdr 1 56Y point mutations in Plasmodium falciparum asymptomatic school children.
 Results: A nested PCR amplifying the 18S small-subunit ribosomal RNA (SSU rRNA) gene of Plasmodium in 205 samples confirmed 76.1% of the isolates as asymptomatic P. falciparum infections, with a substantial proportion 22% of P. malariae infection. Among these, 3.6% were single P. malariae infections and 15.1% were P. falciparum and P. malariae mixed infections. Mixed P. falciparum and P. ovale infections were 2.0%. Of the 156 Plasmodium falciparum, positive samples by species-specific PCR, 107 samples with P. falciparum mono-infection were analyzed for the presence of drug resistant alleles pfcrt 76T and pfmdr1- Y 86. The prevalence of pfcrt 76T mutation (74.6%) was higher than that of the pfmdr1-Y86 mutation (25.4%). Logistic regression analysis of socio-demographic factors predicted no significant association between pfcrt 76T mutation with gender and communities.
 Conclusions: The results indicated a high prevalence of P. malariae and mixed infection in the area under study. The high-level distribution of the pfcrtT76 observed in the study could be possibly attributed to the fact that CQ remained widely used at the community level more than 14 years after withdrawal.

Diversity and phylogenetic relationships of Glossina populations in Nigeria and the Cameroonian border region

BackgroundTsetse flies are vectors of trypanosomes, parasites that cause devastating disease in humans and livestock. In the course of vector control programmes it is necessary to know about the Glossina species present in the study area, the population dynamics and the genetic exchange between tsetse fly populations.ResultsTo achieve an overview of the tsetse fly diversity in Nigeria and at the Nigeria-Cameroon border, tsetse flies were trapped and collected between February and March 2014 and December 2016. Species diversity was determined morphologically and by analysis of Cytochrome C Oxidase SU1 (COI) gene sequences. Internal transcribed spacer-1 (ITS-1) sequences were compared to analyse variations within populations. The most dominant species were G. m. submorsitans, G. tachinoides and G. p. palpalis. In Yankari Game Reserve and Kainji Lake National Park, G. submorsitans and G. tachinoides were most frequent, whereas in Old Oyo National Park and Ijah Gwari G. p. palpalis was the dominant species. Interestingly, four unidentified species were recorded during the survey, for which no information on COI or ITS-1 sequences exists. G. p. palpalis populations showed a segregation in two clusters along the Cameroon-Nigerian border.ConclusionsThe improved understanding of the tsetse populations in Nigeria will support decisions on the scale in which vector control is likely to be more effective. In order to understand in more detail how isolated these populations are, it is recommended that further studies on gene flow be carried out using other markers, including microsatellites.

The genus Cola (Malvaceae) in Cameroon’s Korup National Park, with two novelties

Background and aims – Cola, the second largest genus of the Malvaceae-Sterculioideae comprises 100–135 small to large tree species confined in nature to African forests, though cultivated elsewhere. Current species distribution ranges show that the genus is highly diverse in the seasonally wet forests along the Nigeria-Cameroon border, including the Korup National Park (KNP). In this paper we examine the diversity and abundance of Cola in KNP compared to other forests for which comparable data are available. We also describe two novelties in the genus.Methods – We used inventory data from a 50-ha permanent plot in southern KNP where all Cola trees and saplings down to 1 cm in diameter were tagged, mapped and identified. Additional collections of the genus came from the 11 km trail leading to the plot. Classic herbarium techniques and field observations were used for the morphological identification and description of specimens at MO and YA and from our personal collections. Cola species richness and abundance was estimated from the plot data and compared to other African forest sites for which comparable data are available. The evaluation of the conservation status of the two new species described in this paper followed the IUCN Red List Categories and Criteria. Key results – Twenty-five species of Cola were identified in the southern part of the KNP, including four undescribed species, raising the total number of Cola species in Cameroon to 46. The abundance of the genus in KNP was three orders of magnitude higher than in the Rabi forest in southwestern Gabon or in the Ituri forest in eastern D.R. Congo. This high species richness and abundance suggests that KNP is part of the center of diversity of the genus. Two new species, Cola zemagoana Kenfack & D.W.Thomas and C. mamboana Kenfack & Sainge are described and illustrated. Both species are only known from the lowland rainforest of southwestern Cameroon. Cola zemagoana is narrow endemic of southern KNP and its conservation status is assessed as Endangered. Cola mamboana is confined to the lowland forests of southwestern Cameroon, is locally very abundant in protected areas and is also assigned the conservation status Endangered.

Cameroon-Nigeria Border Conflict Incidence on Trade Patterns and Dynamics Within Near-Border Settlements of the Bakassi Peninsula, Cameroon

Historicity, geo-strategic and economic bearing has snatched the discourse on border environments from contemporary geographical literature. Yet, these environments have stoutly become hotspots for violent expression of conflicting entitlements to natural resources and socio-economic opportunities. The Bakassi Peninsula at West Africa’s lone gulf (of Guinea) which replicates <i>par excellence</i>, the combination of resource-space tussle and conflicting territorial claims and resolution approaches between Nigeria and Cameroon, has unravelled major trends and dynamics of commercial activities for communities within the area. Within this politically hotbed peninsula is Ekondo Titi, a commercial hub undergoing significant dynamics in the periods before, during and after the <i>Bakassi Crisis</i>, laid to rest by the Green Tree Accord whose political palliative was no economic panacea to the quantitative and qualitative trade responses in the area especially on the Cameroonian side. This study purposively sampled 100 respondents involving traders, farmers, council workers and other stakeholders in Ekondo Titi of Cameroon. A chi square analysis at 0.05 level of significance with a degree of freedom of 9, portrayed a significant association between commercial sector dynamics and border insecurity in Ekondo Titi especially as trade patterns assumed a three period pendula-like mood. Post crisis trends reveal an increasingly unaccounted and unofficial cash crop trade outflow towards Nigeria in the dearth of practicable road transport infrastructure, warehouses/storage tanks, and other domestic marketing infrastructure. Post crisis trade management exhibits the need for the government of Cameroon to set in robust confidence building measures while drastically enhancing on the transport and market infrastructure.

Assessing the impact of seasonality on Cross River Gorilla Nest Construction at Kagwene Gorilla Sanctuary, North-West Cameroon

The Cross River gorilla, one of the most endangered subspecies of western gorilla (Gorilla gorilla) is endemic to 12 to 14 sites at the Cameroon-Nigeria border, where it is facing enormous threats from habitat loss, bush meat trade and minor climate changes (seasonal changes). In a strive to reduce the enormous stressors on this subspecies, this study assesses the impact of seasonality on nest construction by Cross River gorillas in the Kagwene Gorilla Sanctuary with the objective of evaluating the impact of seasonal changes on the nest construction. To achieve this goal, the study employed a hunter guided survey team, as well as guides/trackers of the Wildlife Conservation Society. This team regularly tracks and searches the forest for gorilla signs using vegetation trails, food prints, dung, and feeding signs which are subsequently followed onwards to the nesting site. Data were collected from January to December 2014. A total of 268 fresh gorilla nest sites were observed containing 1813 individual nests. Out of the 1813 nests recorded, 39.6% (N=718) of the nests were on the ground and 60.4% (N=1095) on trees. The frequency of each nest type varied significantly among months (P =0.4433). There was a significant effect of season on nest category. Ground categories (bare earth, herbaceous, woody and mixed) were more common in the dry season (74.9%) than in the wet season (25.1%). On the other hand, tree nests were more common in the wet season (77.4%) than in the dry season (22.6%). Mean nest diameter for the two seasons (dry and wet) was 1.1 and 1.3 m, respectively. The mean nest height was 12.5 m for both seasons. Cross River gorillas showed higher preferences for tree nests within the height class interval of 11 to 15 m (49.6%). The distribution of nests across gradient of altitudes did not vary significantly between seasons (P>0.05), and nests were most common on steep slopes (n=810). Seasonality did not significantly affect the choice of slope (P>0.05). There was a significant difference in the habitat types (primary forest, light gap, secondary forest and rock) used for nesting, with primary forest being most preferred. Nest site distribution was predominant in the northern section of the sanctuary. This study reveals that, both temperature and rainfall play an important role in nest construction by Cross River gorilla at Kagwene. Key words: Cross River gorilla, nest, seasonality, Kagwene Gorilla Sanctuary.

Rethinking Witchcraft Confessions in Africa : Imagination on Occult Forces, Morality and Violence among the Ejagham, the Cross River Region

Throughout Africa, societies are found in which the practice of witchcraft confessions is observed. This paper provides ethnographic descriptions of witchcraft confessions among the Ejagham and other Cross River societies of the Cameroon-Nigeria border, which offer a key to reconsidering the interrelationship among witchcraft, morality and attitude of people toward witchcraft in Africa, and investigates the process that leads people to such confessions. The comparative typological classification of African witchcraft and societies proposed by Mary DOUGLAS will be revisited. This paper also reconsiders the issue of witchcraft and social equalization, thereby pointing out in more general terms certain risks and violence that are derived from strict beliefs about 'justice' related to 'morality'. Through these descriptions and analyses, I would like to suggest one approach which enables us to translate and interpret African witchcraft as something common to all human societies in present-day world, while reevaluating certain advantages of social functionalistic interpretations which have been routinely criticized by some recent anthropological discourses.

Nigeria-Cameroon Border Demarcation at a Glance and Lessons Learned for Nepal

The border demarcation between two countries usually takes place after wars or serious conflicts. Nigeria, which has the largest army in Africa, showed that it had a big heart when it reached an agreement with Cameroon as per the 2002 ICJ judgment without waging a war with its much smaller neighbor Cameroon. Although many Nigerians feel that Cameroon has gained a lot more than Nigeria, especially when Nigeria decided to hand over sovereignty of the 1000 sq-km oil-rich Bakassi peninsula to Cameroon, the Nigerian government is eager to make a closure of the boundary demarcation as per the 152-page ICJ judgment.Ever since the demarcation activity started with a pilot project in 2005, many field missions have taken place with the mediation/facilitation of the United Nations, which has provided logistical and partial financial support and has brought in experts from all over the world.The field demarcation along the land, river and ocean boundaries between Nigeria and Cameroon has mostly been completed, except for the final mapping and emplacement of boundary pillars along some sections of the border which are inaccessible or are marked ‘disagreement areas’. There are some serious security threats posed by Boko Haram in the disagreement areas in the north.The best practices used in the Nigeria-Cameroon border demarcation are outlined below. Nepal could take some valuable lessons from the demarcation methods used by these two countries and maintain the political will to carry on the border demarcation works which can be technically and physically challenging and politically complex.Nepalese Journal on Geoinformatics, Vol. 14, 2015, Page: 33-36

Evaluating the potential effectiveness of alternative management scenarios in ape habitat

SUMMARYChoosing appropriate management strategies and effective conservation actions requires information about the future consequences of current conservation actions; however, this crucial information is rarely available to conservation planners. This study applies scenario planning and agent-based modelling (ABM) to assess the potential impact of alternative management strategies on future suitability and functional connectivity of Cross River gorilla (CRG) habitat in the Nigeria–Cameroon border region. The CRG population is small and fragmented, with many subpopulations and migration corridors located outside protected areas. This study used ABM to simulate human land use in the study area over a period of 15 years under different management scenarios and assessed the impact on future suitability and functional connectivity of CRG habitat. The simulations showed that a landscape approach with greater focus on interventions to change human behaviour towards conserving gorillas and sustainable forest use would result in greater improvement in habitat suitability and functional connectivity compared to focusing on improving law enforcement within existing protected areas. However, the best scenarios were when both law enforcement and behaviour change increased. The results highlight the importance of human behaviour change to conservation in human-dominated landscapes and can inform conservation planning and management of other species and in similar landscapes.

The mechanisms and characteristics of a complex rock-debris avalanche at the Nigeria–Cameroon border, West Africa

We describe a rock-debris avalanche which occurred on steep, symmetrical ridges resulting from fracture-controlled erosion in the valley. The fractures were partially filled with clayey materials, probably derived from the weathering of feldspar. Major fault lines trending N–S were located less than 7km from the landslide location. Exposed sections revealed that the basal rock units were migmatites and gneisses, while the upper section consisted of porphyritic granites. A failure of the residual clay-rich soil, composed of visible crystals of feldspar and mica, is thought to have triggered a long chain of events that led to the development of a rock-debris avalanche, which diverted the course of the rivers in the valley. The area was characterised by a shallow water table in the dry season (2 to 3m) and this might have facilitated the formation of a slip surface at the regolith–rock interface. Field observations and laboratory analysis showed that the regolith probably failed first because of high pore pressure build-up and rapid reduction in shear resistance; this then triggered the failure of the fractured rock units. The slope movement was perpendicular to the foliation of the gneissic rocks, which probably contributed to landslide mobility. Of interest was that changing saturation level at constant relative density of about 32% resulted in either complete or limited liquefaction, indicating that the mechanism of failure depended on the moisture content of the regolith.

The compressibility and shear characteristics of soils associated with landslides in geologically different localities—case examples from Nigeria

Field and Shuttle Radar Topographic Mission data were used to create Digital Elevation Model and geologic maps to study the roles of geology, discontinuities, elevation, steep slopes, deep valleys, and drainage patterns on the frequent occurrence of long-travel landslides along the Nigeria–Cameroon border. The undrained shear behaviors of sandy specimens from two localities with different mode and magnitude of landslides were analyzed at different stress levels and related directly to their compressibility and permeability characteristics. The weathered granitic-sandy specimens from Kwande debris avalanche showed significant change in bulk permeability and sample height, and exhibited the greatest evidence of grain crushing. This behavior correlates well with their shear response which manifested in considerable increase in excess pore pressure and drastic reduction of shear resistance. Due to grain crushing, finer grains that lowered permeability were formed at the shear zone. It is likely that the decrease in permeability facilitated the generation of high excess pore pressures leading to significant reduction of shear resistance to low values at steady state. Contrastingly, the reduction in sample height and permeability of Iva valley sands was not as significant, which also correlates with the generation of low excess pore pressure and higher steady state strengths; conditions that may be responsible for the predominance of short-travel slides in the area. The behavior of silica sands, however, which suffered higher grain crushing and reduction in sample height and permeability, appeared closer to that of the samples from the avalanche site.

Informing conservation management about structural versus functional connectivity: A case‐study of Cross River gorillas

Connectivity among subpopulations is vital for the persistence of small and fragmented populations. For management interventions to be effective conservation planners have to make the critical distinction between structural connectivity (based on landscape structure) and functional connectivity (which considers both landscape structure and organism-specific behavioral attributes) which can differ considerably within a given context. We assessed spatial and temporal changes in structural and functional connectivity of the Cross River gorilla Gorilla gorilla diehli (CRG) population in a 12,000 km(2) landscape in the Nigeria-Cameroon border region over a 23-year period, comparing two periods: 1987-2000 and 2000-2010. Despite substantial forest connections between occupied areas, genetic evidence shows that only limited dispersal occurs among CRG subpopulations. We used remotely sensed land-cover data and simulated human pressure (using a spatially explicit agent-based model) to assess human impact on connectivity of the CRG population. We calculated cost-weighted distances between areas occupied by gorillas as measures of connectivity (structural based on land-cover only, functional based on both land-cover and simulated human pressure). Whereas structural connectivity decreased by 5% over the 23-year period, functional connectivity decreased by 11%, with both decreasing more during the latter compared to the earlier period. Our results highlight the increasing threat of isolation of CRG subpopulations due to human disturbance, and provide insight into how increasing human influence may lead to functional isolation of wildlife populations despite habitat continuity, a pressing and common issue in tropical Africa often not accounted for when deciding management interventions. In addition to quantifying threats to connectivity, our study provides crucial evidence for management authorities to identify actions that are more likely to be effective for conservation of species in human-dominated landscapes. Our approach can be easily applied to other species, regions, and scales.