Impacts of Selective Logging and Associated Anthropogenic Disturbance on Intact Forest Landscapes and Apes of Northern Congo

Morgan, David; Strindberg, Samantha; Winston, William; Stephens, Colleen R.; Traub, Cynthia M.; Ayina, Crepin Eyana; Ebika, Sydney T. Ndolo; Mayoukou, Wen; Koni, David; Iyenguet, Fortuné C.; Sanz, Crickette

doi:10.3389/ffgc.2019.00028

Cited by 21 publications

(12 citation statements)

References 85 publications

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“…Our research correlates with peer findings that gorilla population numbers within the study area remain stable [Ando et al, 2008;Nakashima et al, 2013b]. Possible reasons for this are the lack of human pressures within the park [Nakashima et al, 2013a] and previous outbreaks of Ebola within Gabon not impacting MDNP [Georges et al, 1999;Huijbregts et al, 2003;Walsh et al, 2003;WHO, 2003].…”

Section: Gorilla Abundancesupporting

confidence: 86%

Gorilla Abundance Estimations within North-East Moukalaba-Doudou National Park, Gabon

Ismaila¹,

Maloueki²

2021

IJFP

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Accurate measures of animal population densities are essential to evaluate conservation status and implement action plans to ensure species survival. Gorilla numbers were assessed using the recce survey method within Moukalaba-Doudou National Park (MDNP) in Gabon using fresh nest counts of up to 1 week old. We walked 3,592 km within a 23.01-km<sup>2</sup> study site totalling a sampling effort of 297 days. Encounter rate was 0.12 fresh nests per kilometre, and gorilla density estimates generated by home range sizes (by minimal convex polygon) ranged between 1.14 and 1.48 gorillas/km<sup>2</sup>. Gorillas preferred mixed forest for nesting over other habitats (Cheason index value 1.31). Results showed that gorilla density values within the study area concurred with previous studies that used line transect methodologies. We conclude that the choice of sampling design is dependent on environmental conditions characterised by each habitat type and target species.

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Section: Gorilla Abundancesupporting

confidence: 86%

Gorilla Abundance Estimations within North-East Moukalaba-Doudou National Park, Gabon

Ismaila¹,

Maloueki²

2021

IJFP

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“…We conducted surveys in three different sites in the pristine), Republic of Congo, which is part of the Sangha Trinational World heritage site (https://whc.unesco.org/en/list/1380/) (Figure 1). NNNP represents one of the last remaining intact forest landscapes in the Congo Basin (Morgan et al., 2019; Potapov et al., 2017). The vegetation in the NNNP is typically semi‐deciduous rain forest with an altitude between 300 and 500 m. Rainfall is bimodal with a dry season (<100 mm monthly) from December to March and a rainy season from April to November (with peaks around September/October).…”

Section: Methodsmentioning

confidence: 99%

High abundance and large proportion of medium and large duikers in an intact and unhunted afrotropical protected area: Insights into monitoring methods

et al. 2021

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Unsustainable hunting of bushmeat has dramatic impacts on ecological processes and people's livelihoods. Unfortunately, there is often a strong controversy regarding the sustainability of duiker hunting due to their continued presence in bushmeat markets, on the one hand, and the predictions of sustainable harvest models for duiker abundance, on the other. This apparent contradiction is largely due to biased low abundance estimates from dung surveys. We present results from a 52.4 km line transect dung survey using site decay rates to estimate duiker densities. In addition, camera trapping (14,995 camera trap-days) was used to provide detection rates and a baseline for the ratio of blue to red duikers as an index of hunting pressure from Nouabalé-Ndoki National Park, with almost zero levels of hunting. Dung surveys revealed high overall duiker densities (totalling 107.4 duikers per km 2 ) and quick dung decay rate. Camera trapping revealed high-duiker detection rates and a high ratio of red to blue duikers. Pristine protected areas and no-hunting zones continue to act as source habitats for high recruitment of harvested species. We discuss future options for monitoring duikers and applying the ratio of red to blue duikers as an index of the level of duiker hunting. K E Y W O R D Sbiomonitoring, camera trapping, Congo Basin, duikers, dung survey, line transect RésuméMalheureusement, il y a souvent une forte controverse autour de la durabilité de la chasse au céphalophe par sa présence continue sur les marchés de viande en brousse, d'une part, et les prévisions de modèles durables des récoltes liés à l'abondance des céphalophes, d'autre part. Cette contradiction apparente est en grande partie due aux estimations incorrectes faites par le faible nombre des prélèvements des excréments. Nous présentons les résultats d'un relevé des excréments en transects linéaires de 52,4 km en utilisant les taux de décomposition du site pour estimer la densité des céphalophes. En outre, le piégeage photographique (14,995 jours-pièges photographiques) a été utilisé pour fournir des taux de détection et une base de référence pour le rapport entre les céphalophes bleus et les rouges comme indice de la

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“…We found no significant evidence of density-dependent constraints on carrying capacity, even as the number of study groups doubled. Our results provide evidence of stability or population increase on a relatively small spatial scale for western gorillas, and they highlight the value of law enforcement and protected areas, but they do not diminish the importance of improving conservation for this critically endangered species [ 36 , 108 ]. Western gorillas have a slow life history, so even with a positive growth rate, a long time is needed to recover from population disturbances [ 109 ].…”

Section: Discussionmentioning

confidence: 84%

Population dynamics of western gorillas at Mbeli Bai

Robbins

Manguette²,

Breuer³

et al. 2022

PLoS ONE

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Long-term studies of population dynamics can provide insights into life history theory, population ecology, socioecology, conservation biology and wildlife management. Here we examine 25 years of population dynamics of western gorillas at Mbeli Bai, a swampy forest clearing in Nouabalé-Ndoki National Park, the Republic of Congo. The Mbeli population more than doubled from 101 to 226 gorillas during the study. After adjusting for a net influx of gorillas into the study population, the increase represents an inherent growth rate of 0.7% per year, with 95% confidence limits between -0.7% and 2.6%. The influx of gorillas mainly involved immigration of individuals into existing study groups (social dispersal), but it also included the appearance of a few previously unknown groups (locational dispersal). The average group size did not change significantly during the study, which is consistent with the possibility that western gorillas face socioecological constraints on group size, even when the population is increasing. We found no significant evidence of density dependence on female reproductive success or male mating competition. The distribution of gorillas among age/sex categories also did not change significantly, which suggests that the population had a stable age structure. Our results provide evidence of population stability or growth for some western gorillas (albeit within a small area). The results highlight the value of law enforcement, long-term monitoring, and protected areas; but they do not diminish the importance of improving conservation for this critically endangered species.

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Impacts of Selective Logging and Associated Anthropogenic Disturbance on Intact Forest Landscapes and Apes of Northern Congo

Cited by 21 publications

References 85 publications

Gorilla Abundance Estimations within North-East Moukalaba-Doudou National Park, Gabon

Gorilla Abundance Estimations within North-East Moukalaba-Doudou National Park, Gabon

High abundance and large proportion of medium and large duikers in an intact and unhunted afrotropical protected area: Insights into monitoring methods

Population dynamics of western gorillas at Mbeli Bai

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