Aiah Lebbie

Gibourtia copallifera is a rare, range-restricted tree native to the Kasewe Forest Reserve in southern Sierra Leone. Historically exploited for gum copal, it now faces threats from charcoal production due to its high-quality charcoal. Although the species shows good growth in forest patches established 60 years ago, natural regeneration remains minimal. While many tropical tree species form beneficial relationships with arbuscular mycorrhizal fungi (AMF), these associations are still poorly understood in humid regions like Sierra Leone. This study investigated the AMF associations of G. copallifera and assessed changes in mycorrhizal diversity in relation to forest degradation and tree development stages. Soil characterization was conducted through profile analysis, and samples were subjected to laboratory testing. Three soil types were identified within the reserve: K 01—barren land with sparse vegetation; K 02—forest land dominated by G. copallifera ; and K 03—upland fallow agricultural land with shrubs and a few trees. Soil analysis indicates pH values ranging from 5.03 to 5.87 (acidic), with calcium as the most dominant exchangeable base, followed by magnesium, potassium, and sodium. The surface horizon under G. copallifera exhibited the highest total exchangeable bases, and high cation exchange capacity (CEC) was linked to the presence of decomposed plant matter. A total of 22 AMF species were identified in plant root samples, with a significantly higher proportion found in non-degraded forest patches. These accounted for around 68% of AMF species, especially Scutellospora and Gigaspora , along with Glomus and Acaulospora . AMF species richness and diversity were considerably higher in non-degraded patches (3.13 species) than in degraded areas (1.75). Mycorrhizal frequency and intensity were also significantly greater in undisturbed forest sites. AMF colonization peaked in mature trees and was lowest in seedlings, although the variation across trials was not statistically significant (P = 0.07). The study concludes that K01 is unsuitable for G. copallifera due to its shallow depth, which restricts growth. In contrast, K02 and K03 are more favorable for the species. However, many K02 areas have been converted to agricultural land, and in locations where natural forest regeneration is allowed, more aggressive species such as Gmelina arborea and Anisophyllea laurina tend to dominate. Additionally, AMF play a crucial role in promoting the growth of G. copallifera in nutrient-poor soils. These findings are important for informing reintroduction and reforestation strategies for this native tropical tree species.

This study investigates the impact of human activity on the diversity, abundance, and species composition of trees in southwestern Sierra Leone's Kasewe Forest Reserve. The specific objectives are to assess the historical use of Guibourtia copallifera in relation to the reserve and examine community relations with this species. Primary data were collected through a floristic inventory and key informant interviews, focusing on the use of forest land and floral resources. A total of 1,294 living specimens from 74 tree species and 12 lianas, belonging to 61 genera in 27 families, were recorded in the study. The most dominant species were Guibourtia copallifera, followed by Nesogordonia papaverifera, Memecylon normandii , and Gmelina arborea. Other species recorded at lower levels include Homalium africanum, Lindackeria dentata, Pentadesma butyracea, and Santiria trimera. Additionally, 675 stumps from 42 genera in 29 families were identified, with 88 trees showing harvesting marks. The study also recorded 147 old charcoal pits and 76 new charcoal pits. In the Kasewe Forest Reserve, 13 patches of Gmelina arborea plantations, along with 26 old and 11 new farms, were recorded. The study revealed that rapid anthropogenic activities and poor forest management have led to a decline in tree diversity. Edge communities remain crucial for the reserve's health, management, and future. Traditions, culture, and customs play a key role in the reserve's services and products, but the full historical use of the area is poorly documented. These findings highlight the urgent need for effective forest development and a recovery plan for degraded areas.

Sosuga virus (SOSV), a rare human pathogenic paramyxovirus, was first discovered in 2012 when a person became ill after working in South Sudan and Uganda. During an ecological investigation, several species of bats were sampled and tested for SOSV RNA and only one species, the Egyptian rousette bat (ERBs; Rousettus aegyptiacus), tested positive. Since that time, multiple other species have been sampled and ERBs in Uganda have continued to be the only species of bat positive for SOSV infection. Subsequent studies of ERBs with SOSV demonstrated that ERBs are a competent host for SOSV and shed this infectious virus while exhibiting only minor infection-associated pathology. Following the 2014 Ebola outbreak in West Africa, surveillance efforts focused on discovering reservoirs for zoonotic pathogens resulted in the capture and testing of many bat species. Here, SOSV RNA was detected by qRT-PCR only in ERBs captured in the Moyamba District of Sierra Leone in the central region of the country. These findings represent a substantial range extension from East Africa to West Africa for SOSV, suggesting that this paramyxovirus may occur in ERB populations throughout its sub-Saharan African range.

Marburg virus (MARV) causes sporadic outbreaks of severe Marburg virus disease (MVD). Most MVD outbreaks originated in East Africa and field studies in East Africa, South Africa, Zambia, and Gabon identified the Egyptian rousette bat (ERB; Rousettus aegyptiacus) as a natural reservoir. However, the largest recorded MVD outbreak with the highest case–fatality ratio happened in 2005 in Angola, where direct spillover from bats was not shown. Here, collaborative studies by the Centers for Disease Control and Prevention, Njala University, University of California, Davis USAID-PREDICT, and the University of Makeni identify MARV circulating in ERBs in Sierra Leone. PCR, antibody and virus isolation data from 1755 bats of 42 species shows active MARV infection in approximately 2.5% of ERBs. Phylogenetic analysis identifies MARVs that are similar to the Angola strain. These results provide evidence of MARV circulation in West Africa and demonstrate the value of pathogen surveillance to identify previously undetected threats.

Sierra Leone on the west coast of Africa has a monsoon-type climate. Reports by politically influential donors regularly state that Sierra Leone is extremely vulnerable to climate change, but the objective evidence backing these statements is often unreported. Predicting the future climate depends on modelling the West African monsoon; unfortunately, current models give conflicting results. Instead, changes in rainfall over the last four decades are examined to see if there are already significant changes. Rainfall records are extremely limited, so the Climate Hazards Group InfraRed Precipitation with Station daily data at a spatial resolution of 0.05 degrees was used. In addition to total annual rainfall, the characteristics of the early rainy season (critical for farmers), the length of the rainy season and growing season, and the frequency of extreme events were calculated. There is evidence for a significant reduction in annual rainfall in the northwest. There is only limited support for the widely held belief that the start of the rainy season is becoming more erratic and that extreme events are becoming more common. El-Niño was significant in the southeast. If these trends continue, they will exacerbate the consequences of temperature increases (predicted to be between 1 and 2.6 °C by 2060) and negatively affect the livelihoods and agricultural practices of the rural poor.

The last National Forest Inventory of Sierra Leone took place more than four decades ago in 1975. There appears to be no legal definition of “forest” in Sierra Leone and it is sometimes unclear whether reports are referring to the forest as a “land use” or a “land cover”. Estimates of forest loss in the Global Forest Resource Assessment Country Reports are based on the estimated rate during the period 1975 to 1986, and this has not been adjusted for the effects of the civil war, economic booms and busts, and the human population doubling (from about three million in 1975 to over seven million in 2018). Country estimates as part of the FAO (Food and Agriculture Organization of the United Nations) Global Forest Assessment for 2015 aggregate several classes that are not usually considered as “forest” in normal discourse in Sierra Leone (for example, mangrove swamps, rubber plantations and Raphia palm swamps). This paper makes use of maps from 1950, 1975, and 2000/2 to discuss the fate of forests in Sierra Leone. The widely accepted narrative on forest loss in Sierra Leone and generally in West Africa is that it is rapid, drastic and recent. We suggest that the validity of this narrative depends on how you define “forest”. This paper provides a detailed description of what has happened, and at the same time, offers a different view on the relationship between forests and people than the ideas put forward by James Fairhead and Melissa LeachIf we are going to progress the debate about forests in West Africa, up-to-date information and the involvement of all stakeholders are needed to contribute to the debate on what to measure. Otherwise, the decades-old assumption that the area of forest in Sierra Leone lies between less than 5% and more than 75%, provides an error margin that is not useful. This, therefore, necessitates a new forest inventory.

Lebbiea grandiflora (Podostemaceae), a rheophytic herb from the Sewa River rapids in Sierra Leone, is described as a new species. It is the first new African genus of Podostemaceae published for 30 years. First collected in May 2017, the species is assessed as Critically Endangered using the IUCN 2012 standard. It is on the edge of extinction with a small population at a single site threatened by deposition of gravel and sand from alluvial gold and diamond mining upstream, and a planned hydro-electric dam. The new genus is unique in Podostemaceae in a) its highly developed and robust style-stigma structure in which the bases of the two style-stigmas unite to form a bifurcate funneliform-cylindrical structure, with a reflexed, blade-like apex that extends half-way around the perimeter of the ovary-fruit towards the base of the ovary-fruit, b) a specialised andropodium, with robust, self-supporting capacity, having differentiated thickened central, and angled, thinner marginal areas (in other Podostemaceae the andropodial structures are undifferentiated), c) the pillar-like haptera which completely elevate the crustose root above the substrate. Lebbiea is placed in Podostemoideae, necessitating amplification of the delimitation of that subfamily in which it is additionally unique in having the foliose tepals characteristic of the basal subfamilies Weddellinoideae and Tristichoideae.