Journal of Biodiversity and Environmental Sciences (JBES) ISSN: 2220-6663 (Print) 2222-3045 (Online) Vol. 3, No. 8, p. 133-149, 2013 http://www.innspub.net OPEN ACCESS RESEARCH PAPER Species composition and spatial heterogeneity of the seed bank and vegetation in protected and disturbed Miombo Woodland at Christon bank, Zimbabwe Chapano C¹*, Zimudzi C², Makaka CM³, Mapaya RJ³ 1 2 National Herbarium and Botanic Garden, Box A889, Avondale, Harare, Zimbabwe Zimbabwe University of Zimbabwe, Department of Biological Sciences, P.O. Box MP 167, Mt Pleasant, Harare, Zimbabwe 3 Midlands State University, Department of Biological Sciences, P. Bag 9055 Gweru, Zimbabwe Article published on August 24, 2013 Key words: Range management plan, management, rural, collective, rangeland's area. Abstract The regeneration potential of Miombo woodland was evaluated by comparing above ground vegetation and seed banks in a protected area (Mazowe Botanical Reserve) and an adjacent disturbed farming area (Thetford Estates). Sampling was conducted in April and May 2012. In each area 30 sampling plots measuring 10x10 m were randomly selected and the species composition and abundance of all the above ground flora was determined. Soils were collected from each plot and the seedling emergence method was used to determine the species composition of seed bank. The results show that more species were recorded in the protected (264 above ground and 118 in seed bank) than in the disturbed area (119 above ground and 89 in seed bank), showing that disturbance factors were impacting on species composition. The results also show the absence of key Miombo woody species and the dominance of grasses and forbs in the seed banks. We interpreted this to mean that the seed banks cannot sustain the recovery of the Miombo woodland after disturbance. We recommend the use of more improved methods for estimating the size of the seed bank as the seedling emergence method used in this case is known to underestimate the seed bank. *Corresponding Author: Chapano C  cchapano@yahoo.co.uk 133 | Chapano et al. J. Bio. & Env. Sci. 2013 Introduction influence seed bank densities (Dalling, 2004). Soil seed banks play an important role in maintaining Correlations between soil seed banks and above the ecological and genetic diversity of populations ground vegetation vary depending on the types of and community vegetation and environments and the variability of regeneration following disturbance (Tekle and Bekele, the human impacts like deforestation, grazing, fire 2000). They constitute a source of propagules for and also natural factors like drought (Telke and recruitment Bekele, 2000). communities after and in assuring disturbance and provide a mechanism for populations to persist through adverse conditions (Williams et al., 2005). Soil seed bank Most research on soil seed bank were focused on structures are dynamic, and fluctuate seasonally or temperate habitats with fewer studies conducted in annually due to variations resulting from seed the Miombo ecoregion (Anderson et al., 2011). production, seed fall, seed mortality, release of seeds Moreover, the studies in the Miombo have been from dormancy and seed germination (Thompson & inconclusive especifically on how seed banks change Grime 1979). of across environmental gradients. Miombo woodland vegetation structure in African savannas like fire, is the most extensive tropical woodland in Africa grazing and land clearance impact jointly or (Dewees et al., 2011) and presently is being severely separately on any of these processes (Zida et al., altered due to a number of anthropogenic factors 2007). caused by high population growth rates (Campbell et Anthropogenic determinants al., 2006). Studies in the Miombo ecoregion have The relationship between seed banks and standing focused on woodland distribution, ecology, use and vegetation has been investigated in varied studies disturbance (Campbell et al., 2006; Dewees et al., concerned and 2011) and largely exclude the importance of seed reforestation, disturbances, succession, and invasive banks in the ecosystem (Diaz-Villa, 2003). Studies on species purposes the soil seed bank and extant vegetation are (Hopfensperger, 2007). Numerous studies have considered important in understanding community documented similarities in species composition dynamics, between soil seed banks and aboveground vegetation correspondingly provide valuable implications for but others have shown a poor correlation (Tessema et conservation (Li et al, 2011). with and effects for of restoration management restoration and succession and al., 2012). Hopfensperger (2007) reported wider occurrence of woody species and perennial grasses in This study aims at examining the relationships the above ground vegetation and of annual forbs in between soil seed bank structure and above ground the seed bank and attributed the differences to vegetation to assess the potential for vegetation variations and recovery of disturbed habitats in Miombo woodlands. germination rates. The soil seed bank should mirror The Christon bank area is ideal for such a study as it the composition of the existing above ground includes both protected areas at the Mazowe vegetation, provided that seeds arrive only from botanical reserve and many adjacent disturbed areas plants growing in the immediate area. Chaideftou et including Thetford farm estates. in seed dormancy patterns al. (2009), however, reported that not all species in a community may be represented in the seed bank. Material and methods This may be due a number of factors like disturbances Study sites and fragmentation, for example, which may influence The study was conducted at Mazowe Botanic Reserve species richness and abundance in the soil seed bank and the adjacent Thetford Estates (Figure 1). The (Salazar, 2010). Seed predation, pathogen infection study sites are located between latitudes 17° 39´ and and loss in viability following dispersal can also 17° 36´ South and the longitudes 31° 31´ and 31° 01´ 134 | Chapano et al. East, 30 km north of the city of Harare. Precipitation Sampling procedure is variable from year to year averaging around 900 Sampling was carried out in May and April 2012. A mm per year, with mean monthly temperatures modified Whittaker plot design (Stohlgren et al., ranging from 12.9°C in July to 21.6°C in November 1995) was used to collect vegetation data and soil (Tsvuura and Soils are samples from the study area. A total of 30 plots (10 m to the x 10 m) in each of the two study sites were randomly paraferrallitic group (Nyamapfene, 1991). These selected out of 150, identified in aerial photographs. vegetation types shared the same soil and topographic In each sample plot, all plant species were identified characteristics but differed in disturbance history. and the numbers of each species counted. Specimens predominantly Nyamhanga, kaolinitic 2002). and belong which could not be readily identified in the field were collected and later identified at the National Herbarium. The percentage cover of each species was estimated visually in the sub-plots using a 1 m² graduated quadrat and averaged. Soil sampling was done by collecting five soil cores per plot following the method of Sutherland (2006). A 20 cm x 7cm auger was used to collect the soil samples. Soil samples were taken at the plot centre and at each of the four corners of the subplot. Woody material (twigs, branches) and leaf litter were removed before sampling. The soil auger was meticulously cleaned between two samples to avoid contamination. The soil samples were immediately bagged labelled and transported to the laboratory where they were air-dried. Seedling emergence method The seedling emergence method (Roberts 1981) was Fig. 1. Location of the study site in Mazowe District. used to determine species composition of the soil seed bank. The soil samples from each subplot were with thoroughly mixed, sieved through a 10 mm mesh to Brachystegia spiciformis Benth. and Julbernardia separate large pebbles and organic plant debris and globiflora (Benth.) Troupin being the main elements. stored in plastic bags. The experiments were carried The study sites are adjacent to each other but differ in out in glasshouses at the National herbarium in land tenure, management practices and disturbance plastic trays measuring 22 x 16.5 x 5 cm. The trays regimes. The Botanic Reserve is relatively pristine were Miombo woodland that is protected under the homogeneously to a thickness of 4 cm. Four replicates National Parks and Wildlife Act (1975) and managed and one control were used for each microhabitat. by the National Botanic Garden. In contrast, Thetford Controls of pre-washed and sterilized sand soil were is a privately owned farming area subjected to various randomly interspersed among the soil samples to forms of disturbance including crop cultivation, ensure all seeds in the substrate bed were killed grazing and many other human impacts. during sterilization and to account for potential The vegetation is typically Miombo, filled with soil samples and spread contamination of samples by exogenous seeds.The trays were watered twice a week and monitored for 135 | Zanjani et al. J. Bio. & Env. Sci. 2013 four months for seedling emergence. All emerging clearing land for agriculture are among the key seedlings were identified and counted. anthropogenic impacts on savanna woodlands (Luoga, 2000). Data analysis The degree of floristic similarity between vegetation Woody species dominate the aboveground vegetation and seed bank communities was analyzed using the in both disturbed and protected areas whereas the Morisita-Horn soil seed bank is dominated by grasses and (Wolda, 1981) and Sørensen (Hopfensperger, 2007) similarity indices computed herbaceous species (Table 1). using EstimateS statistical software: version 8 (Colwell, 2006). Species rank abundance curves The woody species dominant on the above ground (Oldeland et al., 2010), were used for visual and vegetation include Julbernardia globiflora and numerical comparisons of community patterns in the Combretum on and vegetation and soil seed bank per study site. The Brachystegia Shannon - Weiner’s Diversity Index was calculated Dichrostachys cinerea and Burkea africana on the and compared for each site using the Estimates S disturbed site (Table 2). The dominant grass species software. Species evenness between the soil seed bank on the soil seed bank from the protected area include and above ground vegetation was calculated using Themeda triandra and Andropogon gayanus, and Species evenness E = H’/lnS, where H is Shannon’s the dominant herbaceous flora includes Ocimum molle the spiciformis, site J.globiflora, C.molle, diversity index and lnS is the natural logarithm of the obovatum species richness. disturbed soil seed bank yielded the grass species and Aspilia protected mossambicensis. The Hyperrhenia filipendula and Tristachya nodiflorum and the herbaceous plant Ocimum obovatum. Results and discussion Species composition of the above ground vegetation and soil seed bank Lyaruu and& Backéus (1999), reported similar A total of 264 plant species belonging to 58 families observations in Tanzania. Some recent soil seed bank were recorded in the above ground vegetation (ABV) studies, in agreement with the present findings, have (protected) as compared to 199 species belonging to shown that the seeds of woody species are rare in seed 49 families in the AGV (disturbed). In the soil seed banks compared with herbaceous and grass species in bank there were more species (118 species from 24 various tropical ecosystems (Tekle and Bekele, 2000; families) recorded from the protected area than the Figueroa et al., 2004; Solomon et al., 2006, disturbed area (89 species from 20 families) Esmailzadeh et al., 2011). Of note in this study is the (Appendix A). Seed banks sites had less species than absence in the seed bank of key Miombo woodland aboveground sites. species like Brachystegia spiciformis, Julbernadia globiflora, Combretum spp., Pterocarpus spp, The occurrence of less plant species and families in Burkea africana, Uapaca spp., Pseudolachnostylis the disturbed sites indicates that disturbance has had maprounefolia and Lannea spp. an impact on the vegetation dynamics of the study mean the absence of such seeds in the soil, or possibly area. This is also reflected in the growth forms where conditions for breaking their dormancy were not met more growth forms are represented in the protected during the experiment, or they could have lost their above ground vegetation than in the disturbed (table viability (Lyaruu and Backéus, 1999). The absence of 1). Similar results have been reported in Ethiopia these key species, coupled with the general limited (Tessema et al, 2012) and in South Africa (Dreber et dispersal of Miombo species (Chidumayo and Frost, al, 2011). The disturbance factors in the Thetford 1996) might suggest the failure of the seed bank to area that include veld fires, grazing, wood cutting and sustain the recovery of the woodlands. However, 136 | Chapano et al. This may either J. Bio. & Env. Sci. 2013 Miombo species are known to regenerate largely reticulatus, Richardia scabra, Sphaeranthus randii through coppice regrowth and root suckers rather and the grass Oplismenus hirtellus in the SSBD. than through seeds (Luoga et al., 2004). Presence of these new species in the seed bank could be an indication of an active seed rain in the study The percentage of annual to perennial species is area or possibly these species are successful weeds higher in the soil seed bank (10.8% in SSBP, 10.7% in capable of producing numerous, long lived seeds as SSBD) than in the above ground vegetation (5.5 % in part of their opportunistic survival strategy (Dreber et AGVD, 6.9 % in AGVP). The main annual species al., 2011). observed include Bidens pilosa, Melinis repens, Tagetes minuta and Triumfetta annua, all known to Species richness, evenness and diversity be ephemeral weeds dispersed by wind. Soil seed Species rank abundance distributions for species banks usually contain more annuals than perennials assemblages in the soil seed bank and above ground and more weeds when highly disturbed (Tessema et vegetation are presented in figure 2. The shapes of the al, 2012). Colonization of annual species on grazed distributions are similar and independent of site with sites indicates that grazing is having an impact on the a steep initial slope due to a few species over- performance and seed production of the perennials, represented in both soil seed bank and above ground thereby reducing their seed contribution to the soil vegetation. Species richness is higher in the AGV seed banks (Solomon et al. 2006). Annuals therefore (protected) than the AVG (disturbed) and in the SSB become abundant owing to their high reproductive (protected) than the SSB (disturbed). The shapes of output (Scott et al., 2010) and because perennials the curves also show that the majority of the species often propagate vegetatively (Tessema et al, 2012). on all the sites have more or less similar abundances showing high evenness in species composition. Such A number of ephemeral weeds were recorded only in patterns in species abundance distributions reflect a the soil seed banks and not in the above ground common pattern in community structure at a local vegetation. These include Ageratum conyzoides scale and it can therefore be concluded in agreement subsp. conyzoides, Euphorbia hirta, Hypoestes with Olano et al, (2005) that the seed bank in forskalei, Kohautia caespitosa subsp.brachyloba, semiarid environments may be a good predictor of Murdannia simplex and Plectranthus gracillimus in community composition. the SSBP and Crassocephalum rubens, Phyllanthus Fig. 2. Rank abundance curves for the above ground and seed bank species composition in the two study areas (ranked from most abundant to least abundant). 137 | Chapano et al. .The high species evenness in the study area is Similarity between the soil seed bank and above supported by calculated evenness values shown on ground vegetation table 3. Differences in evenness between aboveground The soil seed banks and aboveground vegetation and an shared a number of common species as shown on underestimation of the seed bank due to the sampling table 4. The above ground vegetation in the protected method used which assumes equal distribution of and disturbed communities shows the highest seeds in the seed bank ignoring other factors like the similarity with similarity indices of 79 % (Morisita- seed shadow, seed type and dispersal mode which are Horn index) and 65 % (Sorensen index). This shows known and& that the human impacts like woodcutting and land Backéus,1999). The Shannon-Wiener diversity indices clearing at Thetford farm have not impacted much on were high for all the study sites ranging from 4.05 in species composition. Of concern, however, are the the SSB (disturbed) to 5.13 in the AGV (protected) very low similarity values shown by both indices (52 (Table 3). This paralleled the species richness of the % Morisita-Horn and 40% Sorenson) between the sites. Species diversity in the study area is high, but protected above ground vegetation and the disturbed diversity indices here are not reliable in assessment of soil seed bank. This is a significant result suggesting disturbance impacts since they only account for that the recovery of the Miombo woodland would not species richness and evenness and not changes in be possible from the seed bank after disturbance. composition. The clearing of woody species leads to Poor correspondence between the seed bank and species composition changes as mainly annual grasses above-ground vegetation has been reported for many and forbs invade the open spaces. ecosystems (Hopfensperger, 2007). seed banks to be could species be a specific result of (Lyaruu Table 1. Species growth frequencies in the studied area (AGVP-Aboveground vegetation protected, AGVDAboveground vegetation disturbed, SSBP-Soil seed bank protected, SSBD-Soil seed bank disturbed). Habitat Species growth form frequencies (%) Climber Fern Grass Herb Orchid Sedge Woody AGVP 0.2 2.4 19.3 35.7 0.1 3.2 39.1 AGVD 0 1.3 24.5 26.4 0 4.0 43.7 SSBP 0 3.1 36.2 42.2 0 7.8 10.7 SSBD 0 2.3 53.6 29.7 0 9.7 5.6 Table 2. The ten most abundant species in each vegetation community in decreasing order of abundance. Above ground vegetation Above ground vegetation (protected) (disturbed) Soil seed bank (protected) Soil seed bank (disturbed) Themeda triandra Brachystegia spiciformis Themeda triandra Hyperrhenia filipendula Tristachya nodiglumis Andropogon gayanus Hyperrhenia filipendula Ocimum obovatum Julbernadia globiflora Julbernadia globiflora Indigofera setiflora Bulbostylis macra Combretum molle Tristachya nodiglumis Digitaria.gazensis Ocimum obovatum Tristachya nodiglumis Combretum molle Aspilia mossambicensis Digitaria eriantha Ocimum obovatum Dichrostachys cinerea Acalypha allenii Heteropogon contortus Indigofera setiflora Burkea africanum Andropogon gayanus Melinis repens Shizostephium artemisiiflorum L.annea discolor Cyperus angolensis Panicum maximum Aspilia mossambicensis Monotes glaber Heteropogon contortus Andropogon gayanus Poulzozia mixta Bulbostylis macra Hyperrhenia filipendula Bidens pilosa 138 | Zanjani et al. J. Bio. & Env. Sci. 2013 Table 3. Species evenness for the above ground vegetation and soil seed bank. Area Evenness Shannon-Weiner AGV protected 0.92 5.13 AGV disturbed 0.92 4.85 SSB protected 0.92 4.37 SSB disturbed 0.90 4.05 Table 4. Shared species and similarity statistics for the four sites in the study area Vegetation types Shared Species First sample Second sample AGVP AGVD AGVP AGVP AGVD Similarity indices Observed Morisita-Horn Sorensen 151 0.789 0.653 SSBP 114 0.763 0.596 SSBD 71 0.516 0.403 SSBP 82 0.600 0.518 AGVD SSBD 83 0.649 0.580 SSBP SSBD 65 0.736 0.631 Conclusion References The results show that anthropogenic disturbance had Anderson TM, Schütz M, Risch AC. 2012. Seed effects on the vegetation dynamics of the study area. germination cues and the importance of the soil seed Declines in bank across an environmental gradient in the species composition and richness, although not severe, are evident in the disturbed area. Serengeti. Oikos 121, 306–312. 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Harms 1 1 Aeschynomene mimosifolia Vatke 3 2 1 1 Ageratum conyzoides L. subsp. conyzoides AGVD 5 Albizia versicolor Oliv. 1 Ampelocissus africana (Lour.) Merr. var. africana 7 Andropogon fastigiatus Sw. 1 Andropogon gayanus Kunth 22 Annona senegalensis Pers. SSBD 1 2 Albizia antunesiana Harms SSBP 1 5 1 1 10 12 9 1 Aristida adscensionis L. 1 2 1 2 Aristida leucophaea Henrard 5 6 5 6 Asparagus africanus Lam. 2 6 Aspilia mossambicensis (Oliv.) Wild 15 7 13 3 Barleria crassa C.B.Clarke 5 1 Basananthe apetala (Baker f.) W.J.de Wilde Berkheya zeyheri (Sond. & Harv.) Oliv. & Hiern subsp. zeyheri 5 Bewsia biflora (Hack.) Gooss. 1 Bidens biternata (Lour.) Merr. & Sherff 1 Bidens pilosa L. 11 Biophytum petersianum Klotzsch 2 2 1 8 9 1 Blumea crispata (Vahl) Merxm. 5 Boophone disticha (L.f.) Herb. 9 1 3 1 Boscia salicifolia Oliv. 1 Brachylaena discolor DC. 3 Brachystegia boehmii Taub. 6 10 4 Brachystegia glaucescens Burtt Davy & Hutch. 12 4 5 Brachystegia spiciformis Benth. 11 22 Bridelia carthatica G.Bertol. 1 2 Bulbostylis macra (Ridl.) C.B.Clarke 11 12 Burkea africana Hook. 4 13 Cassia abbreviata Oliv. 1 1 Catunaregum swinnertonii (S.Moore) Bridson 2 1 142 | Chapano et al. 2 1 10 1 12 J. Bio. & Env. Sci. 2013 Celtis africana Burm.f. 1 1 1 1 Chamaecrista fenarolii (Mendonca & Torre) Lock 1 Chamaecrista mimosoides (L.) Greene 2 5 1 3 Cheilanthes multifida (Sw.) Sw. 18 5 10 3 Chloris pychnothrix Trin. 1 Chlorophytum polystachyum Baker 6 2 Cissus cornifolia (Baker) Planch. 1 Clematopsis villosa (DC.) Hutch. subsp. kirkii (Oliv.) J.Raynal & Brummitt 2 Clerodendrum ternatum Schinz 1 Combretum apiculatum Sond. 1 Combretum erythrophyllum (Burch.) Sond. 1 Combretum hereroense Schinz subsp. hereroense 1 Combretum molle G.Don 19 17 Combretum zeyheri Sond. 3 1 Commelina africana L. 12 10 Commelina benguelensis L. 2 Commelina erecta L. 1 Commelina forskaolii Vahl 2 Commelina welwitcshii C.B.Clarke 2 Commiphora mollis (Oliv.) Engl. 2 Commiphora mossambicensis (Oliver.) Engl. 2 Corchorus kirkii N.E.Br. 2 Crabbea hirsuta Harv. 8 Craspedorhachis africana Benth. 2 1 6 2 1 1 2 7 1 1 Crassocephalum rubens (Jacq.) S.Moore 1 Crotalaria natalitia Meisn. var. natalitia 1 1 Cryptolepis oblongiflora (Meisn.) Schltr. 1 Cussonia arborea A.Rich. 2 Cyanotis lanata Benth. 2 Cymbopogon nardus (L.) Rendle 14 2 8 2 Cyperus angolensis Boeck. 11 8 12 8 Cyperus esculentus L. 5 3 5 Cyperus rotundus L. subsp. rotundus 5 6 7 Cyphostemma buchananii (Planch.) Wild & R.B.Drumm. 2 Cyphostemma junceum (Webb) Wild & R.B.Drumm. 1 Cyphostemma rhodesiae (Gilg & Brandt) Wild & R.B.Drumm. 3 Cyphostemma viscosum (Gilg & R.E.Fr.) Wild & R.B.Drumm. 1 1 Cyrtorchis praetermissa Summerh. subsp. praetermissa 1 Dalbergia nitidula Baker 9 1 1 Danthoniopsis pruinosa C.E.Hubb. 6 1 6 9 2 3 Desmodium barbatum (L.) Benth. var. dimorphum 8 (Baker) 143 | Chapano et al. 1 J. Bio. & Env. Sci. 2013 B.G.Schub. Desmodium rependum (Vahl) DC. 1 Desmodium salicifolium (Poir.) DC. var. salicifolium 1 2 Desmodium tortuosum (Sw.) DC. 1 Desmodium uncinatum (Jacq.) DC. 4 3 1 3 Dichrostachys cinerea (L.) Wight & Arn. 13 14 3 3 Dicoma anomala Sond. 1 5 5 3 Dicoma gerrardii F.C.Wilson 6 1 Digitaria brazzae (Franch.) Stapf 1 Digitaria eriantha Steud. 5 10 4 10 Digitaria gazensis Rendle 14 6 13 5 Digitaria milanjiana (Rendle) Stapf 7 5 7 4 Digitaria velutina (Forssk.) P.Beauv. 1 Diheteropogon amplectens (Nees) Clayton var. katangensis (Chiov.) 7 10 4 8 1 Clayton Dioscorea dumetorum (Kunth) Pax 1 Dioscorea silvatica (Kunth) Eckl. var. brevipes (Burtt Davy) Burkill 1 Diospyros kirkii Hiern 3 Diospyros lycioides Desf. 1 1 Diospyros natalensis (Harv.) Brenan 1 1 Diplolophium zambesianum Hiern 1 Diplorhynchus condylocarpon (Mull.Arg.) Pichon 3 2 Dolichos kilimandscharicus Taub. subsp. kilimandscharicus 2 2 Dombeya rotundifolia (Hochst.) Planch. var. rotundifolia 3 1 Dovyalis zeyheri (Sond.) Warb. 2 1 Duosperma crenatum (Lindau) P.G.Mey. 3 Dyschoriste alba S.Moore 13 4 7 Elephantorhiza goetzei (Harms) Harms 7 2 2 1 1 Emilia discifolia (Oliv.) C.Jeffrey 1 Englerophytum magalismontanum (Sond.) T.D.Penn. 1 Eragrostis cylindriflora Hochst. 1 Eragrostis patens Oliv. 1 1 1 1 Eragrostis racemosa (Thunb.) Steud. 6 2 3 2 Eragrostis sclerantha Nees 5 5 3 4 Eriosema englerianum Harms 1 Eriospermum abyssinicum Baker 9 Erythrina livingstoniana Baker 4 1 Euclea divinorum Hiern 3 3 Euclea natalensis A.DC. subsp. acutifolia F.White 4 3 Euphorbia griseola Pax 1 Euphorbia hirta L. 1 144 | Chapano et al. J. Bio. & Env. Sci. 2013 Fadogia ancylantha Hiern 4 2 Fadogia stenophylla Hiern subsp. odorata (K. Krause) Verdc. 4 1 1 Faurea rochetiana (A.Rich.) Pic.Serm. 3 Faurea saligna Harv. 8 4 1 Ficus abutilifolia (Miq.) Miq. 1 Ficus burkei (Miq.) Miq. 1 Ficus glumosa Delile 1 1 Ficus natalensis Hochst. subsp. graniticola J.E.Burrows 1 1 Ficus sur Forssk. 1 1 Fimbristylis dichotoma (L.) Vahl 1 Flacourtia indica (Burm.f.) Merr. 8 Flueggea virosa (Willd.) Voigt subsp. virosa 2 Friesodelsia obovata (Benth.) Verdc. 3 Garcinia huillensis Oliv. 3 1 1 8 1 Gerbera viridifolia DC. Sch.Bip. subsp. viridifolia 1 Gloriosa superba L. 1 Grewia flavescens Juss. 3 Grewia herbacea Hiern. 1 Grewia monticola Sond. 1 3 Gymnosporia maranguensis (Loes.) Loes. 1 1 Gymnosporia senegalensis (Lam.) Loes. 1 4 Helichrysum nudifolium (L.) Less. 1 Helinus mystacinus (Aiton) Steud. 1 Hermannia depressa N.E.Br. 1 Heteromorpha arborescens (Thunb.) Cham. & Schltdl. 2 Heteropogon contortus (L.) Roem. & Schult. 12 11 Hexalobus monopetalus (A.Rich.) Engl. & Diels 4 1 Hibiscus ovalifolius (Forssk.) Vahl 4 2 1 Hymenodictyon floribundum (Hochst. & Steud.) B.L.Rob. 4 Hyparrhenia filipendula (Hochst.) Stapf 13 21 12 21 Hyparrhenia newtonii (Hack.) Stapf 3 2 3 1 Hyparrhenia schimperi (A.Rich.) Stapf 5 2 4 1 1 12 10 Hyparrhenia variabilis Stapf 1 1 Hyperthelia dissoluta (Steud.) Clayton 4 4 Hypoestes forskaolii (Vahl) Roem. & Schult. 1 Indigofera antunesiana Harms 1 Indigofera arrecta A.Rich. 1 Indigofera astragalina DC. 1 1 Indigofera emarginella A.Rich. var. emarginella 10 Indigofera hilaris Eckl. & Zeyh. 1 Indigofera hirsuta L. var. hirsuta 7 1 145 | Chapano et al. 1 J. Bio. & Env. Sci. 2013 Indigofera lupatana Baker f. 1 Indigofera rhynchocarpa Baker var. rhynchocarpa 13 4 8 Indigofera setifera Baker 18 8 14 Indigofera viscoides Jaub. & Spach var. rogersii (R.E.Fr.) J.B.Gillett 1 Indigofera wildiana J.B.Gillett 1 Inula glomerata Oliv. & Hiern 2 Ipomoea obscura (L.) Ker Gawl.var. obscura 6 Ipomoea verbascoidea Choisy 1 Julbernardia globiflora (Benth.) Troupin 21 Justicia protracta (Nees) T.Anderson 5 Justicia striata (Klotzsch) Bullock subsp. striata 7 Kalanchoe lanceolata (Forssk.) Pers. 3 Kirkia acuminata Oliv. 2 1 2 19 1 2 1 4 1 2 Kohautia caespitosa Schnizl. subsp. brachyloba (Sond.) D.Mantell Lannea discolor (Sond.) Engl. 3 2 13 Lannea edulis (Sond.) Engl. 13 3 Lantana rugosa Thunb. 2 Ledebouria zambesiaca (Baker) S.Venter 5 Leptactina benguelensis (Hook. F.) R.D.Good 3 Leptochloa fusca (L.) Kunth 1 1 Leucus tettensis Vatke 4 1 Lippia javanica (Burm. F.) Spreng. 1 1 Loudetia simplex (Nees) C.E.Hubb. 3 3 Macrotyloma densiflorum (Baker) Verdc. 1 Maerua juncea Pax 1 Margaritaria discoidea (Baill.) G.L.Webster 11 Mariscus deciduous (Boeck.) C.B.Clarke 1 Markhamia obtusifolia (Baker) Sprague 1 Melhania forbesii Mast. 1 Melinis kallimorpha (Clayton) Zizka 2 1 2 1 Melinis longiseta (A.Rich.) Zizka 5 7 4 6 Melinis repens (Willd.) Zizka 2 11 1 10 Melinis subglabra Mez 2 1 2 Microchloa caffra Nees 1 1 3 1 2 Millettia stuhlmannii Taub. 1 Monotes engleri Gilg 3 1 Monotes glaber Sprague 14 13 Murdannia simplex (Vahl) Brenan 1 Mystroxylon aethiopicum (Thunb.) Loes. 1 Mystroxylon aethiopicum (Thunb.) Loes. 1 Neonotonia wightii (Arn.) J.A.Lackey 1 146 | Chapano et al. 2 1 1 J. Bio. & Env. Sci. 2013 Ochna pulchra Hook. 7 7 Ochna schweinfurthiana F.Hoffm. 1 Ocimum americanum L. 2 Ocimum obovatum Benth. var. obovatum 17 11 Olea europaea L. subsp. cuspidata (G.Don.) Cif. 1 Opilia amentacea Roxb. 1 Oplismenus hirtellus (L.) P.Beauv. 1 14 11 1 Oxalis obliquifolia A.Rich. 1 1 1 2 Ozoroa reticulata (Baker f.) R.Fern. & A.Fern. 1 Panicum deustum Thunb. 1 Panicum maximum Jacq. 10 10 9 10 Panicum sabiense Reinvoize 1 Parinari curatellifolia Benth. 6 Passiflora edulis Sims 2 Pavetta schumanniana K.Schum. 1 1 Pellea calomelanos (Sw.) Link var. calomelanos 4 4 Peltophorum africanum Sond. 1 2 Pentas angustifolia (DC.) Verdc. 4 1 4 2 Pericopsis angolensis (Baker) Meeuwen 3 Perotis patens Gand. 2 1 2 1 Philenoptera violacea (Klotze) Schrire 1 Phyllanthus maderasparensis L. 2 2 Phyllanthus pentandrus Schumach. & Thonn. 1 1 1 2 4 4 1 Phyllanthus reticulatus Poir. 1 Pittosporum viridiflorum Sims 1 2 Plectranthus gracillimus (T.C.E.Fr.) Hutch. & Dandy 2 1 Pleurostylia africana Loes. 4 2 Pogonarthria squarrosa (Roem.) & Schult.) Pilg. 1 2 Poulzolzia mixta Solms 15 8 Protea angolensis Welw. 4 1 Protea gaguedi J.F.Gmel. 3 1 Protea welwitschii Engl. 4 3 Pseudarthria hookeri Wight & Arn. 6 3 Pseudolachnostylis maprouneifolia Pax 6 10 Psorospermum febrifugum Spach 5 7 Psydrax livida (Hiern) Bridson 3 1 Pterocarpus angolensis DC. 4 2 Pterocarpus rotundifolius (Sond.) Druce 3 7 Pterolobium stellatum (Forssk.) Brenan 2 Rhoicissus revoilii Planch. 1 Rhoicissus tridentata (L.f.) Wild & R.B.Drumm. 147 | Chapano et al. 3 1 2 2 9 3 3 1 1 J. Bio. & Env. Sci. 2013 Rhus chirindensis Baker f. 2 Rhus dentata Thunb. 1 Rhus leptodictya Diels 3 Rhus longipes Engl. 2 Rhus tenuinervis Engl. var. tenuinervis 2 Rhynchosia minima (L.) DC. 5 2 2 3 2 Rhynchosia resinosa (A.Rich.) Baker 5 1 Richardia scabra L. 2 Rotheca myricoides (Hochst.) D.A.Steane & Mabb. 4 Rottboellia cochinchinensis (Lour.) Clayton 1 Schistostephium artemisiifolium Baker 16 Schizachirium jeffreysii (Hack.) Stapf 1 Schizachyrium sanguineum (Retz.) Alston 1 Senna singueana (Delile) Lock 4 Setaria homonyma (Steud.) Chiov. 2 Setaria longiseta P.Beauv. 2 Setaria pumila (Poir.) Roem. & Schult. 1 Solanecio angulatus (L.) C.Jeffrey 1 Solanum delagoense Dammer 1 1 1 4 11 2 4 3 3 2 Spermacoce senensis (Klotzsch) Hiern 2 Sphaeranthus peduncularis DC. 3 Sphaeranthus randii S.Moore 2 Sphenostylis erecta (Baker f.) Baker 1 Sporobolus festivus A.Rich. 1 Sporobolus ioclados (Trin.) Nees 3 Sporobolus molleri Hack. 1 Sporobolus panicoides A.Rich. 1 Sporobolus pyramidalis P.Beauv. 3 2 Sporobolus sanguineus Rendle 1 1 Steganotaenia araliacea Hochst. 1 Sterculia quinqueloba (Garcke) K.Schum. 2 1 1 2 1 2 3 2 1 2 2 1 Stereochlaena cameronii (Stapf) Pilg. 1 Striga angustifolia (Don) C.J.Saldanha 4 2 1 Strychnos madagascariensis Poir. 3 3 Strychnos spinosa Lam. 2 2 Swartzia madagascariensis Desv. 1 Syzygium guineense (Willd.) DC. 1 Tagetes minuta L. 3 Tapiphyllum velutinum (Hiern) Robyns 1 3 1 1 Tephrosia acaciaefolia Baker 2 1 2 1 Tephrosia decora Baker 6 9 3 6 148 | Chapano et al. J. Bio. & Env. Sci. 2013 Tephrosia elata Deflers 5 3 5 2 Tephrosia linearis (Willd.) Pers. 4 2 1 1 Tephrosia micrantha J.B.Gillett 1 1 1 1 Tephrosia purpurea (L.) Pers. 3 4 2 4 Terminalia brachystemma Hiern 1 Terminalia sericea DC. 1 Terminalia stenostachya Engl. & Diels 3 4 Tetradenia riparia (Hochst.) Codd 7 1 5 Thelipteris confluens (Thunb.) C.V.Morton 2 Themeda triandra Forssk. 23 8 15 Thesium goetzeanum Engl. 2 Thunbergia crispa Burkill 8 1 Thunbergia lancifolia T.Anderson 1 Tinnea rhodesiana S.Moore 2 1 Tithonia rotundifolia (Mill.) S.F.Blake 4 3 Tricalysia niamniamensis Hiern subsp. nodosa (Robbr.) Bridson 1 Tristachya nodiglumis K.Schum. 19 Triumfetta angolensis Sprangue & Hutch. 18 10 2 1 Triumfetta annua L. 3 2 2 Triumfetta rhomboidea Jacq. 1 2 1 Tulbaghia alliaceae (L.f.) Thunb. 1 Turbina oblongata (Choisy) A.Meeuse 1 Tarries nilotica Kotschy & Peyr. 5 3 Uapaca kirkiana Mull.Arg. 4 3 Uapaca nitida Mull.Arg. 3 Vangueria infausta Burch. subsp. infausta 11 Vangueriopsis lanciflora (Hiern) Robyns 1 Vernonia colorata (Willd.) Drake 2 Vernonia glabra (Steetz) Vatke 18 1 9 1 Vigna pygmaea R.E.Fr. 2 Vitex payos (Lour.) Merr. 1 Waltheria indica L. 2 4 Xerophyta equisetoides Baker 5 7 Ximenia americana L. 2 1 Ziziphus abbysinica A.Rich. 1 Ziziphus mucronata Willd. 2 Zornia glochidiata DC. 2 1 149 | Chapano et al. 1 1 1 1