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Introduction
I am an ecologist leading organizations in conservation and NRM in a development context (Africa, Arabia). For 30 years I have been employed by governmental- (German, Rwandan, Dutch), non-governmental (IUCN, WWF), UN- and private (consulting) organizations. Although never a professional requirement, the publication of research and experience has given me much insight and satisfaction. I am currently working on land- and protected area management in West, Central and NE Africa.
Current institution
Current position
- Program Director / Visiting Professor
Additional affiliations
October 2011 - November 2018
August 2005 - September 2008
Position
- Chief Technical Advisor / Team leader
Description
- Team Leader Socotra Conservation and Development Program
May 1993 - February 1998
Position
- Group Leader
Description
- Team leader Management Plan formulation / Ecologist / Pastoral Development Co-ordinator / Sr Researcher at the IUCN project Conservation and Development of the Waza-Logone region
Publications
Publications (158)
Ethiopia is well-known for its outstanding biodiversity and importance as a water tower for surrounding countries. In the mid-1960s, conservation efforts focused on creating protected areas (PAs) that excluded human exploitation and targeted tourism. National Parks, Wildlife Reserves and especially Hunting Areas dominated the country’s first PA map...
Africa’s wildlife decline has received increasing attention, yet underlying reasons have remained opaque. Using generalized additive models of 25 terrestrial and aerial counts, we present West Africa’s first large herbivore population trend series alongside potential drivers. Following Comoé national park’s creation in 1968, large herbivore populat...
A Vegetation Map Western Yemen (1:500,000) covering the western part of the Republic of Yemen (Formerly North Yemen)
Effective wildlife monitoring in a protected area requires an initial understanding of the existing interactions between wildlife and local communities, especially those living in, or around, them. This study examined local ecological knowledge (LEK) on the Critically Endangered Kordofan giraffe (Giraffa camelopardalis antiquorum) held by local com...
Dans un contexte mondial marqué par une diminution alarmante de biodiversité, des efforts de conservation se multiplient pour protéger et restaurer cette espèce emblématique qu’est la girafe. Le Niger, en collaboration avec divers partenaires, a initié en 2018 un projet de translocation des girafes (Giraffa camelopardalis peralta) de Kouré vers la...
The rewilding framework is used to guide the restoration of ecological processes in natural systems, but the framework can also be used in the restoration of social and ecological processes in coupled human and natural systems. We use the case of the large-scale reflooding of the Waza-Logone Floodplain in Cameroon three decades ago as an example of...
Monitoring population trends is pivotal to effective wildlife conservation and management. However, wildlife managers often face many challenges when analyzing time series of census data due to heterogeneities in sampling methodology, strategy, or frequency. We present a three‐step method for modeling trends from time series of count data obtained...
Sub-Saharan Africa is under-represented in global biodiversity datasets, particularly regarding the impact of land use on species’ population abundances. Drawing on recent advances in expert elicitation to ensure data consistency, 200 experts were convened using a modified-Delphi process to estimate ‘intactness scores’: the remaining proportion of...
In recent decades, livestock has intruded into almost every protected area in Central Africa's savannahs, with cattle now more numerous than wildlife (Scholte et al., 2021, Conservation Biology, 36, e13860). Insecurity as a result of the activities of Boko Haram in north-east Nigeria has spread into Cameroon since 2010, causing pastoralists to move...
This chapter presents the distribution, abundance patterns and trends of African buffalo in the 38 countries of its distribution area based on recent aerial and ground census data and feedback from field experts. For the period 2001–2021, we collected abundance data from 163 protected areas or complexes of protected areas and presence data from 711...
Version francaise de fifteen years of delegated management in West and Central Africa (Oryx)
Delegated protected area management (transferring
management responsibilities from a public to a private
partner) has been promoted to give impetus to ailing protected
areas in West and Central Africa. Since their inception
in 2005, the number of partnerships has increased to
20 protected areas covering c. 250,000km2,, an area similar
to that of th...
When in 2010 the world's governments pledged to increase protected area coverage to 17% of the world's land surface, several Central African countries had already set aside 25% of their northern savannas for conservation. To evaluate the effectiveness of this commitment, we analyzed the results of 68 multispecies surveys conducted in the seven main...
Frankincense trees are distributed from Mali in West Africa to India in South Asia (Thulin 2020). With 11 out of 24 species, no other area has a comparable concentration of species of frankincense trees as the tiny Socotra Archipelago with a land surface
of just 4000 km2. Here I describe the discovery of a new species of frankincense tree from the...
In African wildlife conservation literature, southern and southeastern African voices dominate, giving a false impression of pan-Africanism. We present divergent perspectives from West, Central and the Horn of Africa and argue that empathy towards multiple perspectives offers increased resilience to COVID-19 and other crises.
Formal description of a new species of frankincense tree from the islet of Samha, Socotra Archipelago, Yemen.
Sub-Saharan floodplains are sensitive to climatic changes in their upstream drainage basin, a major concern is given the dependency of millions of people for their daily subsistence. Understanding hydroclimatic trends and variability is critical for developing integrated coupled human and natural system models to evaluate future scenarios of vulner...
The discussion about the impact of pastoralists on ecosystems has been profoundly shaped by Hardin’s tragedy of the commons that held pastoralists responsible for overgrazing the range. Research has shown that grazing ecosystems are much more complex and dynamic than was previously assumed and that they can be managed adaptively as commons. However...
Current theoretical models of the commons assert that common-pool resources can only be managed sustainably with clearly defined boundaries around both communities and the resources that they use. In these theoretical models, open access inevitably leads to a tragedy of the commons. However, in many open-access systems, use of common-pool resources...
In recent years, there has been a trend for African states to delegate protected area management to private partners. Central Africa is confronted with rapidly declining wildlife populations, with scarce funding and poor incentives as root causes. This raises the question as to whether management delegation can counter this trend. However, our unde...
Fieldwork rarely goes to plan. In geography, anthropology, earth sciences and other research activities that rely on field data, trade-offs are required between planning and execution. This article addresses the adaptation of research projects to changing fieldwork conditions. It is based on a case study of interdisciplinary and international “Coup...
The decline of wildlife in Central and West African border parks has been directly linked to Islamic terrorism in the region in media and government discourse. Using Waza National Park in the Far North Region of Cameroon as a case study, we show that wildlife declines in the park long preceded the appearance of Boko Haram, the extremist group best...
In 2016, as part of a ceremony in Cameroon’s capital Yaoundé, 2 000 elephant tusks were burned to demonstrate the country’s commitment to fight poaching and illegal trade in wildlife. US Ambassador to the United Nations Samantha Power gave a speech at the event linking poaching to terrorism.
The idea that terror groups like Boko Haram fund their a...
We reviewed the surveys on the status of hippopotamus, hereafter hippo, in the c. 1.3 million ha protected area complex of Faro – Bénoué, North Cameroon. Initiated in 1976, counts were conducted in the second part of the dry season, when the Bénoué and Faro rivers were the parks’ only remaining source of water and observers followed for several day...
This interdisciplinary paper presents an empirical analysis of techno-institutional lock-in in a regional fishery, in the Logone floodplain in the Far North Region of Cameroon. In the Logone floodplain, one fishing technique is spreading exponentially even though it is changing the social, hydrological and ecological dynamics of the system in ways...
Les forêts denses du bassin du Congo sont encore peu impactées par les activités humaines. Toutefois, les stratégies de développement des pays de la région risquent de
profondément modifier cette situation, en multipliant les conflits d’usages. Si exploitation forestière et aires protégées étaient souvent en conflit par le passé, de nouvelles sourc...
The dense forests of the Congo Basin are still relatively unaff ected by human activities.
However, the socio-economic emergence strategies of the countries of the region are
likely to radically change this situation by increasing land-use confl icts. Forestry and
protected areas have to some extent been in conflict in the past, yet new sources of...
North-central Africa (i.e. Cameroon, the Central African Republic and Chad) once held important populations of large mammals, including the hippopotamus Hippopotamus amphibius . Exports of hippopotamus trophies from Cameroon were suspended in 2012 but the species’ status and population trends remain poorly known. Using the same methodology as in 20...
In Central Africa, trophy hunting constitutes an incentive-based approach for sustainable wildlife management. We collected data from the wildlife administration, safari hunting enterprises and local wildlife management committees, to provide an order of magnitude of the financial performance of this sector in Cameroon. In 2012, trophy hunting was...
African floodplains are an excellent example of coupled human–natural systems because they exhibit strong interactions among multiple social, ecological, and hydrological systems. The intra-annual and interannual variations in seasonal flooding have direct and indirect impacts on ecosystems and human lives and livelihoods. Coupled human and natural...
Populations of the common hippopotamus
Hippopotamus amphibius
have undergone widespread decline as a result of habitat conversion and hunting for bushmeat and, increasingly, for ivory. North Cameroon holds important populations of large mammals, including the hippopotamus. The species' status and population trend are poorly known, and led CITES to...
A number of recent studies have suggested that large carnivores are rapidly disappearing in West Africa, including in protected areas (PAs). The extent of this extinction process, however, is poorly known. Here, we quantify the extinction of three large carnivore species (Panthera leo (lion), Acinonyx jubatus (cheetah) and Lycaon pictus (wild dog))...
African wetlands include dambos or headwater
valley grasslands in the upper regions of
catchments, circular pan grasslands in drainage sumps,
linear riverine grasslands in the mid regions of
catchments and broad floodplains, swamps and deltas
in the lower regions of catchments. Plant zonation on
flood frequency and duration gradients occurs in
pred...
While open access to common-pool resources has been equated with a tragedy of the commons, we have found that mobile pastoralists in the Logone Floodplain in Cameroon are sustain ably managing open access to common-pool grazing resources. We have described this pastoral system as a self-organizing complex adaptive system (CAS) in which mobile pasto...
The pastoral system in the Far North Region of Cameroon is best described as an open system in which mobile pastoralists have open access to common-pool grazing resources. We hypothesized that there is a self-organizing management system of open access to common-pool grazing resources and predicted that we would find an Ideal Free Distribution (IFD...
We examined whether mobile pastoralists in the Logone floodplain of Cameroon distribute themselves according to the ideal free distribution (IFD), which predicts that the number of individuals in each area is proportional to the quality and quantity of resources in each area and that all individuals have access to the same amount of resources. We u...
The mobile pastoral system in the far north region of Cameroon is an excellent example of the paradox of pastoral land tenure, in that pastoralists need secure access to pasture and water, but also flexibility in resource use, i.e. the ability to move elsewhere because of spatio-temporal variation in resource availability. In this paper, we draw fr...
Chad is amongst the richest countries in terms of biodiversity in Sahelo-Sudanian Africa with some of the last remaining populations of large mammals that once roamed West-Central Africa. Its protected area (PA) system, made up of three national parks (NP) and seven faunal reserves (FR) and introduced 40 years ago to focus on the protection of larg...
Socotra Island (Yemen), a global biodiversity hotspot, is characterized by high geo-morphological and biological diversity. In this study, we present a high-resolution vegetation map of the island based on combining vegetation analysis and classification with remote sensing. Two different image classification approaches were tested to assess the mo...
The discussion about the impact of pastoralists on ecosystems has been profoundly shaped by Hardin’s tragedy of the commons that held pastoralists responsible for overgrazing the range. Research has shown that grazing ecosystems are much more complex and dynamic than was previously assumed and that they can be managed adaptively as commons. However...
The Socotra archipelago, Yemen, in the north-west Indian Ocean, has outstanding endemic biodiversity, and was listed as a World Heritage Site in 2008. Although inhabited for 6 millennia Socotra only began to open up to the outside world in 1990. With conservation interventions starting prior to major developments, and building on centuries-old low-...
Some have argued that anthropologists have a moral responsibility to advocate on behalf of research subjects suffering from structural and other forms of violence. However, advocacy is not without its problems; action taken on behalf of one's research subjects may have adverse consequences for others. This is our current predicament. Violence and i...
A raft of recent studies has highlighted a major decline in large mammal populations in many of Africa’s protected areas. A recent continent-wide assessment represented a major step forward also in terms of quantifying the decline on a regional basis, but fell short in its sampling and analysis. In this paper, a way out of the “black box” of large...
The discussion about the impact of pastoral systems on ecosystems has been profoundly shaped by Hardin’s “tragedy of the commons”
argument that held pastoralists responsible for overgrazing the range. Recent studies have shown that grazing ecosystems are
much more complex and dynamic than was previously assumed and that pastoralists adaptively mana...
The climate of Socotra, influenced by the Indian Ocean Monsoon, is poorly known, hampering understanding
of its paleoclimate and (endemic) biodiversity. Mean annual rainfall and temperature, measured
in a network of meteorological stations from 2002 to 06, were 216 mm and 28.9 �C. Combined with cloud
cover information from satellite images, this da...
In September 2007 and February 2008, I carried out systematic counts and observations where I had
conducted similar counts in and around Wadi Rima downstream of Medinat ash Shirq in 1988–1990.
The numbers of birds dependent on the wadi bed, Hamerkops Scopus umbretta, egrets, herons,
waders and wagtails, were well within their 1988–90 range. The deg...
Over the last three decades, vegetation surveys in southwest Arabia have documented the existence of a small number of valley forest patches. A well-known area is in Wadi Rijaf, Jabal Bura, a protected area which has recently been surveyed by the current authors. The other valley forest sites in southwest Arabia have not been surveyed for over 15 y...
The isolated massif Jabal Bura (Yemen) is home to the largest area of ‘valley forest’ in southwest Arabia's western escarpment mountains. This study surveys the composition of this very rare forest and records the diversity of vascular plant species. It notes the valley forest as the home of several regionally rare species and records new locations...
Training needs assessments have revealed the need for people-oriented training to increase the job performance of African protected area (PA) managers. The Garoua regional wildlife college for francophone Africa (Cameroon) developed the first long (diploma and certificate) and refresher courses in community conservation for mid-career PA managers a...
Questions
Questions (3)
We recently observed males of Roan and Waterbuck with broken horns in Bouba Ndjida National Park (North Cameroon), both antelope species occurring there at (relatively) high densities (>1-5 ind. km2 ).
Whereas regularly mention is made of horn breakage of antelopes in captivity, surprisingly little is reported from the wild. For example in the recent standard work Mammals of Africa (Hoffmann and Kingdon 2013), only in passing horn breakage is mentioned, and only for species such as Red-fronted gazelle, Giant Eland, Kob, Puku, (female !) Hartebeest, etc. The species accounts on e.g. Roan, Waterbuck, Topi, Bushbuck, Impala, etc. do not mention horn breakage, although known to occur (see also references below).
I am aware of only two quantitative studies on African antelope horn breakage: Gosling et al. (1987) on the relatively high level of horn breaking of Topi on leks in Mara (Kenya), and especially Packer (1983) who quantified for some ten thousand individuals of 13 antelope species the horn breakage frequency in Manyara, Serengeti and Ngorongoro (Tanzania).
With the rapid decline in antelope numbers in many African national parks, one expects that areas with high antelope densities, including leks (Kob, Lechwe, Topi, often in vulnerable floodplains), will decline, likely even disproportionally. The percentage of horn breakage may then drop (disproportionally) as well and may be used as indicator of the health of an antelope population. If confirmed, frequency of horn breakage should be reported as standard parameter in (terrestrial) counts.
Who has antelope horn breakage data or is aware of studies that can be used to underpin (or reject) this assumption?
References
Gosling, L.M., M. Petrie, M.E. Rainy. 1987. Lekking in topi: a high cost, specialist strategy. Animal Behaviour: 35: 2616–618
Kingdon, J. & M. Hoffmann (eds). 2013. The Mammals of Africa. Vol. VI. Pigs, Hippopotamuses, Chevrotain, Giraffes, Deer and Bovids. Bloomsbury Publishing, London.
Packer, C. 1983. Sexual dimorphism: the horns of African antelopes. Science 16: 1191-1193
We are conducting a vegetation study in the Logone Floodplain and Lake Maga (Far North Cameroon) with the goal of comparing the vegetation (in terms of value for herbivores, in particular cattle) in the two areas. The Logone floodplain has a single 3- month rainy season, directly followed by 2-3 months of flooding. The 5-6 months growing season is followed by a pronounced dry season. Especially the higher, ‘drier’, parts of the floodplain are then subject of frequent fire, producing regrowth. The flooding around Lake Maga seems to be much more prolonged (4-5 months ?) , and continues right into the ‘dry’ season.
One of the methods involves measuring the above-ground biomass in these plains, as proxy for annual production. We have experience in the Logone Floodplain, where we have followed the floristic composition in a 17 km transect since the 1990s (Scholte et al. 2000, see link) and measured above-ground biomass in 1994, 1995 and 1996, when grasses start to dry (upon the recession of the floods), Scholte 2007, see link. However, in the Lake Maga area where we just started working, this is not possible because water remains for much longer than 2-3 months and cattle start grazing when the area is still flooded (see picture attached).
The question is how to do the sampling for above-ground biomass measurement in the Lake Maga area. At what point in the transect? When in the season? The concern is how the measurements in the Logone floodplain and around Lake Maga can be meaningfully compared.
I regularly use time series of total large mammal and waterbird counts, to indicate population trends (see for example Scholte 2006, 2013 both in my RG profile). I often add trend-lines (linear or other regression, through a simple Excel exercise) to illustrate them. However, I receive comments that presenting such time series without ‘statistics’ (not further specified), lacks (in my own words) scientific rigor. We are currently working on modeling antelope population trends inspired by Joseph Ogutu’s work in E.Africa (‘using a flexible multivariate semi parametric generalized linear mixed model with a negative binomial error distribution and a log link function. The model smoothes the population trend, specified a cubic B-spline, etc.’ Ogutu et al. 2011), but this only works with sufficient observations and is rather cumbersome.
My question is two-fold:
- Am I right that for total counts (contrary to transect or other partial counts for which limits of confidence can be calculated) ‘statistics’ makes little sense?
- What are alternative ways to present total count time-series allowing an appreciation of their reliability and/or trend ?
