Itwara Central Forest Reserve

A(i)Site contains one or more globally threatened species, C(iii)Site contains nationally threatened or restricted habitat or vegetation types, AND/OR habitats that have severely declined in extent nationally

Itwara qualifies as an IPA under sub-criterion A(i) triggered by eight threatened species including three Endangered and five Vulnerable species. This site also triggers criterion C(iii), as one of the five best sites for nationally for Vulnerable medium altitude evergreen forest.

Itwara Central Forest Reserve (CFR) is located within the Albertine Rift area, on the rift escarpment around 25 km south of Lake Albert, across the districts of Kabarole and Kyenjojo in Western Uganda. The site is known to be important for a number of threatened plant species. Fieldwork was undertaken at this site in 2023 as part of the Uganda TIPAs project and some of the below information is derived from observations and collections made.

Eight plant species that are threatened with extinction are known from Itwara CFR. The Endangered species, Tiliacora latifolia, is of particular importance as a Ugandan endemic known from only five sites nationally. Two other Endangered species are known from this site, Eggelingia ligulifolia and Vepris eggelingii, both of which are thought to be threatened at this site by disturbance caused by tree felling (Amani et al. 2022; Fischer et al. 2019). This could have a significant impact on E. linguifolia as an epiphytic orchid. This species is only known at this site from one collection made in 1943 and therefore more research is required to better understand the population of E. linguifolia at Itwara.
In addition to these Endangered species, five Vulnerable species are known from this IPA. One of these, Turraeanthus africana, differs from the other four in that it is widespread across central and western Africa. But as a valuable timber species, it has been overexploited and populations have been depleted in parts of its range (Barstow 2020). The Ugandan Albertine Rift represents the easternmost limit of this species’ range and as such Itwara is an important site for conserving this species both nationally and globally. Other Vulnerable species of note include Rhipidoglossum bilobatum, a second threatened epiphytic orchid species, and Brachystephanus glaberrimus, an understorey herb or shrub, both of which are cross-border Albertine Rift endemics. The latter species was last collected at Itwara in 1950, but many Brachystephanus species display periodic, monocarpic mass-flowering, with life cycles of several years to a decade, and so can be easily overlooked or under-collected if botanical expeditions do not coincide with flowering events. Good habitat for this species remains and so it is likely still extant at this site but under collected due to this reproduction strategy.
Rytigynia bagshawei var. lebrunii was collected during fieldwork by the Uganda TIPAs project in 2023. This taxon was previously only known from the Central Africa floral region (D.R. Congo, Rwanda and Burundi), although was subsequently collected at Kalinzu during the same fieldwork. Further surveying will likely reveal additional interesting species from this site.
Alongside species of conservation importance, this site is one of the five best nationally for the medium altitude evergreen forest, a Vulnerable habitat in Uganda, encompassing 4.6% of the national resource. This habitat type is limited to higher altitudes and other high moisture areas influenced by Lake Victoria.

Itwara CFR is dominated by moist evergreen forest, categorised as Parinari Forest by Langdale-Brown et al. (1964). Dominant species include Olea welwitschii and Parinari excelsa (Howard 1991). In the areas to the south of the site that were surveyed during 2023 fieldwork, common forest taxa included Trema orientalis, Abilizia, Celtis and Tabernaemontana, possibly associated with past disturbance and regeneration.
The site has a gently undulating topology and is underlaid by sedimentary geology strongly folded and metamorphosed, with the most common features being the quartzite ridges and forming most of the ridges. These are usually fringed by schist, and most of the low ground is probably underlain by gneiss and similar rocks. Wamisu and Sogahi Rivers that drain northwards into River Muzizi dissect Itwara (Ministry of Water and Environment 2008).

Itwara is surrounded by tea plantations and it is suspected that the scarcity of land in turn increases pressure on Itwara (CUPTD Workshop, pers. comm. 2023). Threats at this site include charcoal production, pit sawing and agricultural encroachment (Mugume et al. 2015). In addition, the invasive species Senna spectabilis and Broussonetia papyrifera have been observed at this site (CUPTD Workshop, pers. comm. 2023).
Large areas of the north-west of the site are under forestry plantation, in line with the 2008-2018 Management Plan for the site (Ministry of Water and Environment 2008; Google Earth 2023). Satellite imagery and the Langdale-Brown et al. (1964) vegetation classification suggest this area was previously a savannah – forest mosaic. While the known species of conservation importance at this site are all forest species, without ecological impact surveys prior to the establishment of these forests, it is not clear whether any species of conservation importance were lost through this habitat transformation. In addition, there may be ongoing impacts on ecosystem function and services caused by the establishment of forest here, particularly related to watershed regulation. However, the provision of productive forests in this area likely mitigates against disturbance elsewhere in the reserve, helping to conserve the important resident species. The management plan also called for restoration of degraded areas of forest and the demarcation of forest stands of high conservation value. This was based mostly on landscape features, such as proximity to rivers and slope inclines, and could be further informed by the distribution of threatened and endemic species within this site.
Alongside this work, Wildlife Conservation Society Uganda partnered with NFA for forest restoration work at the site to help protect forests and the Lake Albert Water Management Zone (WCS 2021).

The forest is used by local people as a source of timber, charcoal and medicines (Davenport et al. 1996; Mujuni 2018). Wild coffee species, Coffea canephora and C. eugenioides, are known from this site (Davis et al. 2023).
Itwara lies within the Lake Albert watershed, with the Wamisu and Sogahi rivers running through it and draining northwards (Howard 1991; Ministry of Water and Environment 2008).
Several primate species including grey-cheeked mangabey (VU) and chimpanzee (EN) are known from this IPA – the forests provide important habitats for their conservation (Mugume et al. 2015; Rich et al. 2020). Although this site is not a major tourist destination compared to neighbouring protected areas, there may be good tourist potential due the diversity of plants, mammals and birds and its proximity to Fort Portal (Ministry of Water and Environment 2008).

Sophie Richards, Royal Botanic Gardens, Kew

Iain Darbyshire, Royal Botanic Gardens, Kew

Samuel Ojelel, Makerere University Herbarium

James Kalema, Makerere University Herbarium