Mapping of biodiversity hubs and key ecosystem services as a tool for shaping optimal areas for conservation

such as Balaeniceps rex (Shoebill). Ibanda-Makera natural forest in Kirehe district is a gallery forest associated with woodland and savannah in the east and papyrus swamp in the south toward Akagera river. The forest shelters the CE Blighia unijugate (Triangle tops), the CE Netta erythrophthalma (Southern Pochard), the VU Francolinus afer (Red-necked Spurfowl Franco- lin), and the VU Numida meleagris (Helmeted Guineafowl). 3.2 Ecosystem service distribution The important areas for carbon storage are distributed mainly in places with forests in south- west, west, and north-west of Rwanda, these are respectively NNP (Rusizi, Nyamasheke, Nyar- uguru, Nyamagabe, Karongi districts), GMNP (Ngororero, Rutsiro, Nyabihu, Rubavu dis- tricts), and VNP (Rubavu, Nyabihu, Musanze, and Burera districts); shrubs in east of Rwanda mainly in ANP (Gatsibo, Kayonza, and Nyagatate districts), Gabiro, Gako and Nasho military domains (respectively in Gatsibo, Bugesera, and Kirehe districts); wetlands mainly in the north and south-east of Rwanda, these are Rugezi wetland (Burera district) and Rweru & Mugesera wetland complex (Bugesera, Ngoma, Rwamagana districts); and lakes, mainly Kivu (Rubavu, Rutsiro, Karongi, Nyamasheke, Rusizi districts), Burera and Ruhondo (Burera and Musanze districts), Muhazi (Gicumbi, Gasabo, Gatsibo, Rwamagana, and Kayonza districts), Rweru & Mugesera (Rwamagana, Ngoma, and Bugesera district) and Ihema (Kayonza dis- trict). The amount of carbon storage corresponds to the amount of avoided flow of carbon

into the atmosphere hence weakens further exacerbating effects to global climate change. Important areas that contribute the most to the Annual water balance in Rwanda are gener- ally located to higher elevation and are directly related to the level of the area’s green land cover. Sources and water upstream points are attributed higher values compared to the down- stream of flow, hence their points of use are not as valuable as their points of production. Spa- tial distribution map shows highest values in the western part of Rwanda (Congo-Nile divide) that corresponds to higher elevation, most dense vegetation, highest annual rainfall, and the source of many water flows towards the Nile river in the east and Congo river in the west. Rwanda has the highest population density on African mainland and human settlement is predominantly characterized by scattered pattern that spread on the country’s hills and high- lands. The largest urban centers are located in the country’s center. Human footprint on water quality-diarrheal diseases is directly linked to human settlement, the map shows that PA such as NNP, VNP, ANP, Rugezi wetland and Rweru & Mugesera complex offer the opportunities of creation of safe water sources and effective sanitation systems that can guarantee the protec- tion from contamination to diarrheal diseases. Human footprint on water quality (annual) involves all sorts of pollutants that are linked to human activities that either worsen or degrade stream, river, lake, ocean, aquifer, or other body

water’s turbidity or damage the water quality by rendering it toxic to humans or environment. Anthropogenic activities such as mining and quarries exploitation around wetlands and water bodies and industrial effluents from cities such as Kigali threaten by sedimentation and pollution the downstream water bodies due to poor sewage and inexistant waste treatment systems. On the other hand, the map (Fig 3) shows that PAs and other unprotected less undisturbed territo- ries contribute less to human footprint on water quality (annual) but instead serve as retention pond that improve water quality before releasing it towards downstream water bodies. 4 Discussion 4.1 The delineation of NP system vs biodiversity hubs While we don’t reject the fact that the biodiversity is generally well conserved and protected within PAs whilst out of them the biodiversity is highly threatened mainly due to intense PLOS ONE How do old national parks cope with regenerating conservation mission? PLOS ONE | https://doi.org/10.1371/journal.pone.0253151 August 17, 2021 12 / 20