Gola Forest Research Articles

Dietary flexibility of western red colobus in two protected areas with contrasting anthropogenic pressure

Food distribution and abundance can affect intra- and inter-dietary variation in non-human primates, influencing feeding ecology and altering behaviour. Natural and/or human-induced actions can influence the dynamics between primates and the environment, with associated impacts on socio-ecology and demography. This relationship in anthropogenic landscapes, however, is poorly understood. Here, we use DNA metabarcoding to obtain high resolution dietary diversity data, and multivariate generalised linear models to investigate variation in the diet of this threatened primate. We characterise the diet of the western red colobus (Piliocolobus badius) in both the better preserved Gola Rainforest National Park (GRNP, Sierra Leone), and in the fragmented forests of Cantanhez National Park (CNP, Guinea-Bissau), and evaluate biological, ecological and temporal differences. Dietary plant species richness was high in both protected areas, and the type of plants consumed varied significantly across seasons, space, and time. Although we identify dependence on a few key plants, red colobus in CNP consumed a higher average number of plant taxa than in GRNP, and 11% of the diet consisted of cultivated foods (e.g. mango). This is the first time a molecular approach has been used to investigate red colobus diet, and reveal dietary flexibility in degraded forests. Predicting the consequences of dietary change on long-term population persistence, however, remains a significant knowledge gap. Nevertheless, our results provide critical information to inform targeted regional conservation planning and implementation.

Forest-dependent bird communities of West African cocoa agroforests are influenced by landscape context and local habitat management

We undertook nearly 300 point counts of birds in cocoa plantations around Gola Rainforest National Park, eastern Sierra Leone, to assess how their vegetation structure, management and landscape context influence bird communities and the distribution of four globally threatened or forest-restricted species. Forest bird species richness, and the occurrence of Yellow-casqued Hornbill (Ceratogymna elata), were higher in abandoned than in actively managed cocoa farms. Yellow-casqued Hornbill presence was also associated with higher canopy volume and Brown-cheeked Hornbill (Bycanistes cylindricus) was associated with greater forest cover in the surrounding landscape. Overall forest bird species richness was associated with the interaction between canopy volume and proportion of forest in the surrounding landscape. Our results indicate that where forest cover is low in the landscape, low-intensity cocoa agroforestry can provide compensatory habitat for forest bird species, but when forest cover is high, cocoa that is more forest-like in structure may not lead to increased bird species richness, although it may benefit certain species. Most habitat structure variables, other than canopy volume and openness of understorey, were poor predictors of most of the variables analysed, suggesting that within the narrow range of observed production intensity, management has little impact on bird communities once productivity increases above zero by rehabilitating abandoned farms. However, over 60% of the species recorded and over half of all recorded detections were of biome-restricted species, suggesting that low-intensity cocoa plantations hold considerable conservation value. Changes in cocoa management may therefore impact those species.

The bean method as a tool to measure sensitive behavior.

Conservationists need to measure human behavior to guide decisions and evaluate their impact. However, activities can be misreported and reporting accuracy may change following conservation interventions, making it hard to verify any apparent changes. Techniques for asking sensitive questions are increasingly integrated into survey designs to improve data quality, but some can be costly or hard for nonexperts to implement. We demonstrate a straightforward, low-cost approach, the bean method in which respondents give anonymous answers by adding a colored bean to a jar to denote a yes or no response. We applied the bean method to measure wild-meat hunting and trading over 2 years at a conservation-project (hunting reduction) site in Gola Forest, Liberia. We extended the technique to accommodate questions about hunting and meat-selling frequency. We compared responses given using the bean method and direct questioning for groups that did and did not participate in conservation interventions. Results from the bean method corresponded to those from direct questioning, and there was no indication of change in question sensitivity following conservation interventions. Estimates from both methods indicated that wild-meat trading decreased in project and nonproject households (from 36% to 20%) and that hunting decreased in 1 project group (38-28%). Where inconsistent answers were given (2-6% of respondents), differences were in both directions and were most likely attributable to measurement error. The bean method was quick and straightforward to administer in a low-literacy setting. We showed how it can be modified for answers of more than 2 categories and consider it a valuable tool that could be adapted for a wide range of conservation settings.

Low abundance of the Endangered timneh parrot Psittacus timneh in one of its presumed strongholds

AbstractAlthough both the grey parrot Psittacus erithacus and the recently recognized timneh parrot Psittacus timneh are categorized as Endangered because of harvest for the pet trade and loss of habitat, the latter has a much smaller range and may be largely restricted to a few stronghold areas. In March–April 2018 we surveyed for a total of 114 hours in and around one of these presumed strongholds, the large and well-protected Gola Rainforest National Park, the Sierra Leonean portion of the Gola Transboundary Peace Park. Timneh parrots were encountered at a rate of 0.1 groups/h in the National Park and 0.3 in the buffer zone, indicating densities of 1–3 individuals per km2. These figures are similar to recent density estimates from the Liberian side of the Peace Park, suggesting that the transboundary population amounts to c. 2,400 individuals inside the Park and an unknown number in the surrounding areas. Densities of the timneh parrot may be generally low even in strongholds, its numbers may be declining steeply, and the global population size is probably lower than previously believed.

Incentives and social relationships of hunters and traders in a Liberian bushmeat system

Hunting provides livelihoods and food security for a large number of people across the tropics but endangers wildlife populations. Effective management requires understanding both social and economic dynamics of local bushmeat systems, yet social elements such as relationships between actors are often overlooked. We provide the first detailed description of a rural hunting system in Liberia, from interviews with 205 hunters and 50 traders in the Gola Forest. We found bushmeat contributed substantially to local livelihoods and earnings from hunting and trading were high relative to local alternatives (median US$120 and $US262/month, hunters and traders respectively). Most of hunters' catch was sold to traders (85% of harvested biomass) and subsequently transported to urban markets (65% of all harvested biomass). Local consumption accounted for 27% of total harvest. Financial risks from meat confiscation were primarily born by traders, many of whom were women, and 60% perceived this as a motivation to reduce trading. By contrast, the most commonly stated motivation to reduce hunting was the time demanded by alternative activities such as farming. This discrepancy implies that livelihood support initiatives and law enforcement tools may play distinct roles across groups. Relationships between hunters and traders were complex and involved a variety of credit arrangements. Interpersonal trust played an important role, with mistrust of hunters being cited by 12% of traders as the principle barrier for profiting from bushmeat trade. Our findings provide context for designing conservation strategies and suggest that underlying social processes deserve closer attention in bushmeat research.

Unconditional Transfers and Tropical Forest Conservation: Evidence from a Randomized Control Trial in Sierra Leone

AbstractUnconditional conservation payments are increasingly used by non‐governmental conservation organizations to further their environmental objectives. One key objective in many conservation projects that use such unconditional payments schemes is the protection of tropical forest ecosystems in buffer zone areas around protected parks where the scope of instating mandatory restrictions is more limited. We use a randomized controlled trial to evaluate the impact of unconditional livelihood payments to local communities on land use outside a protected area—the Gola Rainforest National Park—which is a biodiversity hotspot on the border of Sierra Leone and Liberia. High resolution RapidEye satellite imagery from before and after the intervention was used to determine land use changes in treated and control villages. We find support for the hypothesis that unconditional payments, in this setting, increase land clearance in the short run. The study constitutes one of the first attempts to use evidence from a randomized control trial to evaluate the efficacy of conservation payments and provides insights for further research.

Improving cocoa harvest can mitigate for crop damage by wildlife in a forest-agriculture matrix

Shade-grown cocoa has been suggested as a more carbon and biodiversity friendly land use around protected forests compared with slash-and-burn farmland, and may be particularly suitable for achieving livelihood, biodiversity and forest protection goals of REDD+ projects. However, loss of cocoa to wildlife perceived to come from forest protected areas can result in lower profits for local people, reduced livelihood benefits from development projects and negative perceptions of conservation leading to reduced conservation impacts. We collected and analysed data on cocoa pod numbers and damage by animals over 2 months of the cocoa growing season, coinciding with peak harvesting season, from 39 plots at 3 forest edge communities around Gola Rainforest National Park, Sierra Leone. We estimate that 20% of pods across the cocoa plantations studied were damaged by wildlife, though there was high spatial variation. Of damaged pods where the animal group responsible could be identified, 87.2% of the damage was by monkeys, 11.1% by rats or squirrels and 1.7% by chimpanzees. Binomial mixed modelling of the proportion of pods damaged by wildlife indicated that this was higher closer to settlements and where pod density was lower. This indicates that the species causing the most damage in this system are disturbance-tolerant generalists which are not dependent on the protected forest, that mitigation measures should be concentrated where damage is highest, particularly close to settlements, and that increasing cocoa yield in these communities could offset damage by wildlife and therefore still be a viable option for, for example, REDD+ projects, even where crop raiding is common.

Optimal Monitoring Strategy to Detect Rule-breaking: A Power and Simulation Approach Parameterised with Field Data from Gola Rainforest National Park, Sierra Leone

Protected area designation aims to protect forests from illegal activities such as hunting. However, the effectiveness of protection and how this changes over time in response to protection measures is difficult to assess, including the design of monitoring programmes able to detect changes. We present new data on rule-breaking prevalence in Gola Rainforest National Park, Sierra Leone, and use these data in spatially explicit simulations to assess the survey effort and design required to detect change and assess the effect of rule-breaker behaviour to these designs. Despite being a protected area, rule-breaking (in the form of signs of hunting) occurred in almost 70% of 1 km survey squares but repeating this baseline survey of 53 survey squares would be insufficient to detect change. A much larger survey effort of 200-400 survey squares would be required to detect a 25% change in rule-breaking. Simulations highlight the extent to which rule-breaker behaviour, particularly hunter range size, influenced the likelihood of detecting change and importance of understanding this for survey design. A dedicated monitoring programme able to detect changes in the level of rule-breaking required an unrealistic level of resources, and we recommend combining monitoring with ranger patrol activities to reduce overall costs and employing questionnaire-based methods.

The importance of protected and unprotected areas for colony occupancy and colony size in White-necked Picathartes Picathartes gymnocephalus in and around Gola Rainforest National Park, Sierra Leone

SummaryMost attention on tropical biodiversity conservation has focussed on protected areas. Recognising and enhancing the value of biodiversity outside, as well as inside, protected areas is increasingly important given recognition that biodiversity targets will not be met through protected areas alone. We investigated the extent to which protection influences colony occupancy and colony size of a species of conservation concern, the rock-nesting White-necked Picathartes Picathartes gymnocephalus. We used mixed models to compare long term trends at 42 colonies located both inside and outside a protected area of forest, Gola Rainforest National Park, and considered colonies further inside the boundary as being better protected. Colony occupation was primarily predicted by the level of protection, with occupation highest within protected areas, but was not different between colonies situated close to or far from the boundary. Mean colony occupation was consistently high in protected areas, and lower in unprotected areas. The surface area of colony rocks was also an important predictor with larger rock faces having a higher probability of occupancy. Our best models also included distance to forested habitat, presence of cleared forest and evidence of hunting as less important predictors. Over the eight-year study, after controlling for rock surface area, active colony size declined significantly. However, declines were only significant in colonies in unprotected forest, whilst colonies located within protected areas were buffered from significant decline. Together this suggests colony occupancy and the number of active nests are influenced by protection and human disturbance. Although a lack of demographic and population dynamic work on picathartes prevents identifying mechanisms, we show that despite unprotected colonies having lower occupancy and fewer active nests they can persist in human altered and disturbed areas, partly because larger traditionally used rocks remain important nesting sites.

Drivers of aboveground wood production in a lowland tropical forest of West Africa: teasing apart the roles of tree density, tree diversity, soil phosphorus, and historical logging.

Tropical forests currently play a key role in regulating the terrestrial carbon cycle and abating climate change by storing carbon in wood. However, there remains considerable uncertainty as to whether tropical forests will continue to act as carbon sinks in the face of increased pressure from expanding human activities. Consequently, understanding what drives productivity in tropical forests is critical. We used permanent forest plot data from the Gola Rainforest National Park (Sierra Leone) – one of the largest tracts of intact tropical moist forest in West Africa – to explore how (1) stand basal area and tree diversity, (2) past disturbance associated with past logging, and (3) underlying soil nutrient gradients interact to determine rates of aboveground wood production (AWP). We started by statistically modeling the diameter growth of individual trees and used these models to estimate AWP for 142 permanent forest plots. We then used structural equation modeling to explore the direct and indirect pathways which shape rates of AWP. Across the plot network, stand basal area emerged as the strongest determinant of AWP, with densely packed stands exhibiting the fastest rates of AWP. In addition to stand packing density, both tree diversity and soil phosphorus content were also positively related to productivity. By contrast, historical logging activities negatively impacted AWP through the removal of large trees, which contributed disproportionately to productivity. Understanding what determines variation in wood production across tropical forest landscapes requires accounting for multiple interacting drivers – with stand structure, tree diversity, and soil nutrients all playing a key role. Importantly, our results also indicate that logging activities can have a long‐lasting impact on a forest's ability to sequester and store carbon, emphasizing the importance of safeguarding old‐growth tropical forests.

Who believes in witches? Institutional flux in Sierra Leone

Witchcraft has been documented across the globe. The widespread occurrence of such beliefs in modern Africa affects politics, economic development, and poverty alleviation. Anthropologists have analysed the semiotics of African witchcraft, but there is less information on distributional issues. An important question is which communities are most affected, and why? Using data from a survey of 182 villages and 2,443 household heads in the Gola Forest region of eastern Sierra Leone, we examine three manifestations of witchcraft – concerns, conflicts, and detection. We find that where patrimonial relations of agrarian production remain strong, and in settings where market forces are now well established, witchcraft is less of a concern. By contrast, witchcraft manifestations are higher in communities experiencing the competing pull of patrimonial and market norms. Witchcraft, we conclude, is a product of normative ambiguity.

Spatial and temporal variation of carbon stocks in a lowland tropical forest in West Africa

Understanding the nature and cause of spatial and temporal variation in forest carbon is critical for implementation of climate mitigation strategies such as REDD. Such knowledge is lacking and hard to acquire in resource poor regions such as West Africa’s Upper Guinea where benefits of such schemes for forest conservation could have great impact.We undertook a systematic and representative survey of an entire Upper Guinea forest – Gola Forest in southeast Sierra Leone - by measuring over 600plots (0.125ha) in order to quantify the level of spatial variation in C that might exist within a discrete forest type and relate this to historic and contemporary impacts on the forest. We modelled current C stocks and compared these with values calculated from historic surveys. Mean C content in above ground biomass was c. 160Mgha−1. The southern part of the forest which was subject to heavier logging in the 1980s had a lower C content (121–144Mgha−1) compared to the less disturbed central areas (186Mgha−1). Volumes of extracted timber and distance to settlements around the forest explained 42% of the variation in C content. Elevation, slope and other metrics of human impact such as distance to roads did not explain significant additional variation. A survey from the 1950s recorded much higher carbon content than currently found in the south of the forest. This accords with evidence that commercial logging in this area was destructively high. However, old surveys from the late 1960s/early 1970s in less disturbed areas recorded lower carbon content than present. Most of the past surveys were in areas that had not yet been commercially logged so the accumulation in biomass in the last 40years implies recovery from a much older disturbance event, or a change in environmental conditions promoting growth.As a typical Upper Guinean forest, our results from Gola demonstrate the long term impacts of disturbance events on carbon stocks and how these can vary greatly at small scales, highlighting the need for representative and regionally relevant empirical data to inform REDD type initiatives. Nonetheless these forests remain important for carbon sequestration and storage in the region despite this history and the parts of the forest with no recorded logging activity that increased in carbon in recent decades with levels now akin to undisturbed plots reported from elsewhere in the region demonstrate the sequestration potential these forests provide once adequately protected.

Long term stability of White-necked Picathartes population in south-east Sierra Leone

SummaryWhite-necked PicathartesPicathartes gymnocephalusis a globally ‘Vulnerable’ bird endemic to the highly threatened Upper Guinea forests in West Africa. In an environment under a high level of threat, the high breeding site fidelity (or breeding site persistence) of this species enables long term monitoring of colony site occupancy, colony size and other breeding parameters, which provide multiple indicators of population status. We surveyed known colony sites and searched for new sites in three recent breeding seasons in order to assess the current population status in the most important part of their range in Sierra Leone, the Gola Forest. We found 157 active nests at 40 colonies, equating to at least 314 adult birds. Less than half of the known colonies were protected by the Gola Forest Reserve. Colonies outside the reserve tended to be confined to larger rocks and subject to disturbance from human activities in close proximity, but did not have fewer active nests in them. Colonies outside the reserve were also more likely to be inactive in a given year whereas all colonies inside the reserve were active in every survey year. A predictive distribution model indicated that the survey region could have as many as 234 nests equating to at least 468 breeding birds. There was no evidence that mean colony size had declined since surveys undertaken in the 1980s and 1990s but it was not possible to compare colony abandonment rates inside and outside the reserve over that time period. Clutch and brood sizes were similar in each year, though brood size appeared slightly lower in the third survey year possibly because of a slightly later survey date. Mean clutch and brood sizes reported during the study period were similar to those found in the 1980s and 1990s. We conclude that the population of White-necked Picathartes in the Gola Forest area has been relatively stable over the last two decades, reflecting both the efficacy of protection afforded by the Gola Forest Reserve and presumably low pressure to farm new areas in the nearby community forest. However, regular monitoring of colonies both inside and outside the reserve is required to detect any systematic impact on the birds as pressure for land increases.

Peasant grievance and insurgency in Sierra Leone: Judicial serfdom as a driver of conflict

Was the civil war in Sierra Leone (1991–2002) fought for diamonds, or was it a peasant insurgency motivated by agrarian grievances? The evidence on both sides is less than conclusive. This article scrutinizes the peasant insurgency argument via a more rigorous methodology. Hypotheses concerning intra-peasant tensions over marriage and farm labour are derived from an examination of the anthropological literature. These are tested using econometric tools, applied to data from a randomized survey of 2,239 households in 178 villages surrounding the Gola Forest in eastern and southern Sierra Leone, the cradle of the war. It is shown that a decade after the war ended peasant disputes over marriage continue to mark out an incipient class divide in isolated rural communities, as evidenced by cases presented in local courts and family moots. Disputes mainly involve a village elder suing a young man with weak social protection. Fines are exceptionally high, and mostly paid off in the form of coerced farm labour. It is argued that grievance over this long-standing form of labour exploitation fed insurgency, and contributed to the otherwise puzzlingly high levels of peasant-upon-peasant violence associated with the war in Sierra Leone.

Using Artefactual Field Experiments to Learn about the Incentives for Sustainable Forest Use in Developing Economies

We implement a public goods game and a social intervention modeled after a public goods game in rural Sierra Leone near the Gola Forest Reserve. We also collect demographic, economic and forest conservation data on households in the area. We use this data to assess the mapping of social preferences from the artefactual field experiment (AFE) into real world behavior. We find evidence of heterogeneity in shifting factors between the AFE, the field experiment, and conservation outcomes. We also find evidence that social controls like war violence and witchcraft may explain some of this correlation.

The impact of civil war on forest wildlife in West Africa: mammals in Gola Forest, Sierra Leone

AbstractHuman conflicts may sometimes benefit wildlife by depopulating wilderness areas but there is evidence from Africa that the impacts tend to be negative. The forested states of West Africa have experienced much recent human conflict but there have been no assessments of impacts on the wildlife. We conducted surveys of mammals in the 710-km2Gola Forest reserves to assess the impact of the 1991–2001 civil war in Sierra Leone. Gola is the most important remaining tract of lowland forest in the country and a key site for the conservation of the highly threatened forests of the Upper Guinea region. We found that Gola has survived well despite being in the heart of the area occupied by the rebels. We recorded 44 species of larger mammal, including 18 threatened, near-threatened and endemic species, accounting for all species recorded in pre-war surveys and adding several more (African buffaloSyncerus caffer nanusand water chevrotainHyemoschus aquaticus). Populations of primates were healthy with little evidence of decline. Duiker detection rates were low and further work is required to confirm their numbers as they include five species endemic (or near endemic) to the Upper Guinea region, three of which are threatened. However, the population of African forest elephantsLoxodonta cyclotishas collapsed, with only a few individuals remaining from c. 110 in the mid 1980s. We conclude that peacetime pressures from the bushmeat trade, clearance for agriculture, logging and mining are likely to be far greater for Gola than the pressures from the civil war.

Establishing a national monitoring programme for White‐shouldered Ibis in Cambodia

The results from both projects have been included in the Biodiversity of Gola Forest report (Klop et al. 2008), which provides the biological data underlying the recently published management plan for Gola Forest (Gola Forest Programme 2009). Additionally, the White-necked Picathartes survey work has formed a basis for future monitoring of the species in Gola Forest and the first resurvey has taken place in January 2009.

Threatened species surveys in the Gola Forest Reserves, Sierra Leone

Threatened species surveys in the Gola Forest Reserves, Sierra Leone

Photographic evidence of Jentink’s duiker in the Gola Forest Reserves, Sierra Leone

Photographic evidence of Jentink’s duiker in the Gola Forest Reserves, Sierra Leone

Selected notes on birds of Gola Forest and surroundings, Sierra Leone, including three new species for the country

Selected notes on birds of Gola Forest and surroundings, Sierra Leone, including three new species for the country