Polish Botanical Journal 62(2): 203–212, 2017 e-ISSN 2084-4352 DOI: 10.1515/pbj-2017-0030 ISSN 1641-8190 BRYOPHYTE RECORDS FROM THE EASTERN NIGERIAN HIGHLANDS Izuchuk O. Ezukanma1, Oluwatoyin T. Ogundipe, George I. Nodza & Tamás Pócs Abstract. A preliminary inventory of the eastern Nigerian highlands yielded 27 bryophyte species (5 liverworts, 22 mosses), including 13 species new for the country (2 liverworts and 11 mosses). The large percentage of new national records (ca 52%) indicates that the eastern Nigerian highland has rich bryophyte diversity and is undercollected. A more detailed inventory of the region using more rigorous sampling protocols is recommended. Key words: biodiversity, endemism, highlands, liverworts, mosses, national parks, Nigeria Izuchuk O. Ezukanma, Oluwatoyin T. Ogundipe & George I. Nodza, Department of Botany, University of Lagos, Akoka-Yaba, Lagos, Nigeria, 101017; e-mail: [email protected] Tamás Pócs, Institute of Biology, Eszterházy Károly University, Eger, Pf. 43, H-3301, Hungary Introduction Important centers of bryophyte diversity and en- (Johansson 1974). The two other highlands on demism in Africa are found mostly on isolated the West African mainland are the Jos (Bauchi) mountain massifs and islands (Hodgetts et al. Plateau in Nigeria and the highlands of eastern 2000). Most of tropical Africa is arid or semi-arid Nigeria and western Cameroon. Others are the lowland which is notably less species-rich than islands of Bioko (Fernando Po) and Sao Tomé tropical America or Southeast Asia, but many parts (Wigginton & Jones 2004). of Africa, especially the highlands, are known to While the bryophyte flora of Bioko and Sao harbor a rich flora. Most of the mountain massifs in Tomé and Principe (Müller & Pócs 2007; Müller the continent are located in East Africa, especially et al. 2007) and western Cameroon (Jones 1990) the Uluguru and Usambara Mountains, which are are fairly well known, there is only a single re- part of the ancient crystalline mountains of the cord of a moss, Wijkia trichocolea (Müll. Hal.) Eastern Arc located in Tanzania, and the highlands H. A. Crum [syn. Acanthocladium trichocolea of Ethiopia through the Ruwenzori to Mt. Mulanje (Mull. Hal.) Broth., Sematophyllum trichocolea in the south. The volcanic peaks of Kilimanjaro, (Mull. Hal.) Kindb.] (Walters 2017) from the ad- Mt. Kenya, Mt. Elgon and the Virunga Mountains joining region in eastern Nigeria. Wijkia tricho- are also very rich in species (Hodgetts et al. 2000). colea is widely distributed in East and Central However, large mountain areas are poorly rep- Africa but the only other record for West Africa resented in West Africa, with only three substantial is from Togo (O’Shea 2006). areas above 1000 m a.s.l.: the Fouta Djallon-Loma- There are two sizeable protected areas on the Nimba massifs, also known as the Guinea high- eastern Nigerian highlands that are less degraded lands, a series of ridges and peaks which rise up by anthropopression. These are the Ngel Nyaki to >1000 m a.s.l. stretching from Fouta-Djalon Forest Reserve and Gashaka-Gunti National Park. in Guinea to the Dans massifs in Ivory Coast These two areas are included in this study. The Ngel Nyaki Forest Reserve (ca 7.2 km2), 2 1 Corresponding author which is part of the 46 km Ngel Nyaki Forest Received: 4 Sept. 2017. Publication date(s): online fast track, n/a; in print and online issues, 15 Dec. 2017 204 POLISH BOTANICAL JOURNAL 62(2). 2017 Fig. 1. Map of eastern Nigerian highlands, with sampling points indicated. Reserve and Game Sanctuary, was gazetted as closed canopy forest limited to the stream valleys a local-authority forest under the Gashaka-Mam- (Akinsoji 2013). The forest is one of the floristi- billa native authority Forest Order in April 1969 cally diverse montane-submontane forest stands (Chapman & Chapman 2001). It is located towards in Nigeria (Dowsett-Lemaire 1989) and the most the western escarpment of the Mambilla Plateau diverse one on the Mambilla plateau (Chapman in the southeastern corner of Taraba State, NE & Chapman, 2001). Nigeria. The Mambilla Plateau (11°00′–11°30′E, Gashaka-Gunti National Park (6731 km2; 6°30′–7°15′N) is a highland region which is part 06°58′–08°05′N, 11°11′–12°13′E) is the largest of the Cameroon volcanic line, bordering the Re- protected area within Nigeria, established through public of Cameroon. The Ngel Nyaki Forest Re- a federal decree in 1991 by the merging of two serve is in the bowl of an old volcanic crater from previously existing game reserves (Gumnior 1400–1600 m a.s.l. The forest can be reached on & Soummer 2012): the Gashaka Game Reserve foot from Yelwa village past Mayo Jigawal, from in (present-day) Taraba State, which is the southern where it is less than an hour’s walk to the upper section of the reserve; and the Gunti Game Re- edge of the forest (Ihuma et al. 2011). The forest serve in (present-day) Adamawa State, which is is drained by numerous watercourses which unite the northern section (Dunn 1995). The park is in to form the main rivers, then to discharge into the a largely secluded mountainous region of north- River Benue, Nigeria’s second-largest river. east Nigeria adjacent to the international border The Ngel Nyaki Forest Reserve is a mosaic of with Cameroon and to the Mambilla Plateau. With mountain-top grassland, montane and submontane the exception of a few lonely footpaths winding I. O. EZUKANMA ET AL.: BRYOPHYTES FROM THE EASTERN NIGERIAN HIGHLANDS 205 through the forested mountain towards Cameroon, falling each year is highly variable. The dry season there is no road across to this region. is usually from December to March when little or The southern sector of the park is mountainous no rains fall, with severe atmospheric aridity and and contains vast expanses of rainforest as well great extremes of temperature. The onset of the as areas of woodland and montane grassland. The season is marked by dry, sand-laden Harmattan terrain is rugged and is marked by steep, thickly winds blowing down from the northeast off the forested slopes, deep plunging valleys, precipitous Sahara Desert. The climatic conditions in the park escarpments and swift-flowing rivers. The terrain are highly variable and depend on elevation, to- in the northern sector is much more amenable, pography and location. The forested basin below with relatively flat grassland and woodland. Alti- Chappal Waddi, where the southern sector of the tude ranges from 450 m a.s.l. in the wild savannah park faces and intercepts the inbound prevailing plains of the northern sector to 2400 m a.s.l. on southwesterly moisture-laden winds from the At- the peaks and pinnacles of Gangirwal, which is lantic Ocean, corresponds to the wettest areas, with Nigeria’s topmost mountain. mean annual precipitation in excess of 3000 mm. Gashaka-Gunti National Park is considered to The driest regions of the park are in the northern be rich in biodiversity (Oates et al. 2004) on ac- sector, with a shorter rainy season often lasting count of the intricate mosaic of montane grassland, only from May to October, with mean annual rain- savannah woodland, swamp, lakes, mighty rivers, fall less than 1300 mm. Daytime temperatures may dark lowland rainforest, and luxuriant, montane reach 40°C in the shade around March but tend to rainforest strewn with ferns and orchids. Each drop below 5°C at higher altitudes in December. habitat supports its own distinctive community of Sudden storms and hail are common occurrences plants and animals. Equally high mountain ranges on Gangirwal Mountain. in the area act to trap rain-clouds blowing in off the During a research and collection expedition by Atlantic Ocean, thus ensuring abundant rainfall, the University of Lagos Ecology Research Group easily enough to support large patches of rainforest in November 2015, a random collection of bryo- throughout the southern park sector. Lowland rain- phytes was gathered by Izuchuk O. Ezukanma (IE), forests are also able to thrive along the park’s many mostly from substrates along the trail on the as- river valleys, where they are more correctly known cent to the mountains and numerous streams and as gallery forests. Mubi and Tukur (2012) reported river courses, without recourse to any sampling that plant species diversity and composition varied protocol or attempts to distinguish species in the with altitude; for instance, in the low-altitude range field (see Fig. 1 and Table 1). Voucher specimens (240–599 m a.s.l.) the common species included are deposited at the University of Lagos Herbarium Uapaca togoensis Pax, Crossopteryx februfuga (ULH). Nomenclature follows Söderström et al. Benth., Brachystegia eurycoma Harms and Andira (2015) and Wigginton (2004, 2009) for liverworts, inermis (W. Wright) DC. The species dominating and O’Shea (1995, 2006) for mosses. Species new at 600–1319 m a.s.l. were Daniellia oliveri (Rolfe) to Nigeria are asterisked (*). Hutch. & Dalziel, Hymenocardia acida Tul. and Terminalia glaucescens Planch. ex Laness., while Enumeration of species in the 1320–1885 m a.s.l. range the notable spe- cies were Combretum spp., Entada africana Guill. Marchantiophyta & Perr. and Lannea schimperi Engl. However, there is no record of bryophytes from this region. *Cheilolejeunea montagnei (Gottsche ex Mont.) The two protected areas on the eastern Nige- R. M. Schust. rian highlands share similar climatic conditions. Specimen examined. On exfoliating Eucalyptus tree There is usually a marked wet season from April to bark at less than 2 m height on trunk in Eucalyptus plan- November when virtually all rains fall, with many tation, Nyel-Nyaki, Yelwa, Mambilla Plateau, 1600 m rainy days, although the timing and amount of rain a.s.l., 18 Nov.