Zanzibar-Inhambane Deciduous Forest

Dry deciduous forests occur scattered along the entire length of Mozambique north of Massinga. They are characterized by trees such as Adansonia digitata, Afzelia quanzensis, Balanites maughamii, Chlorophora excelsa, Cordyla africana, Khaya nyasica, Millettia stuhlmannii, Pteleopsis myrtifolia, Sterculia appendiculata and the endemic Dialium mossambicense (Fabaceae), Fernandoa magnifica (Bignoniaceae) and Inhambanella henriquesii (Sapotaceae). Other endemic trees include Acacia robusta subsp. usambarensis, (Fabaceae), Cassipourea mossambicensis (Rhizophoraceae), Dolichandrona alba (Bignoniaceae), Grewia conocarpa (Tiliaceae) and Pleioceras orientala (Apocynaceae). The sub-canopy is usually well developed and often forms a thick almost impenetrable layer of deciduous and semi-deciduous shrubs including the endemic Salacia orientalis (Celastraceae). There is a form of semi-deciduous forest mainly confined to the sublittoral belt of ancient dunes but its floristic composition varies considerable. Some of the more characteristic species include Celtis africana, Dialium schlechteri, Morus mesozygia, Trachylobium verrucosum and the endemic or near endemic Cola mossambicensis (Sterculiaceae) and Pseudobersama mossambicensis (Meliaceae).

Zanzibar-Inhambane Miombo Woodland

This, the most extensive type of woodland in the BioProvince, is represented by a floristically impoverished version of Miomba dominated by various species of Brachystegia and Julbernardia globiflora. For example, Brachystegia spiciformis woodland is extensively developed on ‘Sol do Save’ sublittoral sand dunes between the Sabi and Limpopo rivers. Some of the endemic species found here include the trees Carpodiptera africana and Grewia transzambesica (Tiliaceae), the shrubs Maerua scandens (Capparidaceae) and Tetracera boiviniana (Dilleniaceae) and the perennial herb Jatropha scaposa (Euphorbiaceae).

Zanzibar-Inhambane Scrub Forest

Scrub forest dominated by Diospyros cornii and Manikara mochisia occurs in the interior parts of the BioProvince in Kenya and southern Somalia. The lower canopy is characterized by Bivinia jabertii, Croton pseudopulchellus, Diospyros consolatae, Euclea natalensis, Excoecaria venenifera, Haplocoelum foliosum, Ochna thomasiana, Sideroxylon inerme, Thespesia danis, Thylachium africanum, Xeromorpha nilotica and the endemic Grandidiera boivinii (Flacourtiaceae) and Suregada zanzibarensis (Euphorbiaceae). Climbers and epiphytes, however, are almost absent, and apart from a few stands of Sanseviera, few species occur in the herb layer.

Zanzibar-Inhambane Bushland and Thicket

Where unfavourable soil conditions prevent the development of forest, various types of bushland and thicket have developed. On the coral limestone in parts of Kenya, for example, a climax evergreen thicket characterized by Haplocoelum inoploem, Harrisonia abyssinica, Lannea stuhlmannii, Ludia mauritiana, Monikara sansibarensois, Millettia usaramensis, Monanthotaxis fornicata, Pycnocoma littoralis, Sterculia rhynocarpa, Uvaria leptocladen and the endemic Cussonia zimmermanii (Dichopetalaceae) and Suregada zanzibarensis (Euphorbiaceae) is one of the main types of thicket. Other endemics found in evergreen thicket, particularly coastal thicket, include the shrubs Dichapetalum aureonites (Dichapetalaceae) and Ochna beirensis (Ochnaceae) and the climber Traspis mosambica (Malpighiaceae). Also in the coastal zone, especially in the area between Nacada and Mucojo in Mozambique, a thicket largely composed of deciduous species occurs. The characteristic species include Bathia macrocalyx, Dichrostachys cinerea, Combretum pisoniiflorum, Gossypioides kirkii, Guilbourtia schliebenii, Landolphia kirkii, Mimosa busseana, Platysepalum inopinatum, Pseudoprospis euryphylla and the endemic Dialium mossambicense. It is also characterized by the presence of scattered tall trees such as Manikara altissima and the endemic Bombax rhodognapholon (Bombacaceae). Other endemics generally associated with coastal bush and thicket include the shrubs Capparis lilacina, C. orthocantha (Capparidaceae), Commiphora serrata (Burseraceae), Ochna angustata (Ochaceae), Vernonia inhacensis (Asteraceae), the herbaceous forb Diplocyclos tenuis (Cucurbitaceae) and the grass Cenchrus mitis (Poaceae).  

Zanzibar-Inhambane Coastal Dune Vegetation (General)

The coastal dunes of this BioProvince normally include a pioneer zone of sand binding species that eventually creates conditions suitable for a dune thicket. This in turn slowly allows the development of dune forest. Along the Mozambique coast the main pioneer species are Canavalia maritima, Cyperus maritimus, Dactyloctenium aequptiacum, Ipomoea pes-caprae, Launaea sarmentosa, Scaevola thunbergii, Sesuvium portulacastrum, Sophora tomentosa, Sporobolus virginicus, Tephrosia canescens and the endemic Sophora inhambanensis. Other endemic species associated with these dunes are the shrubs Cussonia arenicola (Araliaceae) and Fagara schlecteri (Rutaceae), and the herbaceous species Cleome stricta (Capparidaceae), Hermannia micropetala (Sterculiaceae), Polygala francisci (Polygalaceae) and Tricliceras lanceolatum (Turneraceae).  Moving landward into the dune thicket zone there is a degree of variation in species composition. In southern Mozambique there is often a dense low cover of the endemic bush Grewia occidentalis var. littoralis (Malvaceae), while in more southerly areas Mimusops caffra is usually the dominant shrubby species. The endemic species of these coastal thickets include the shrubs Elaeodendron fruticosum (Celastraceae) and Memecylon sessilicarpum (Melastomataceae), the climber Triaspis suffulta (Malpighiaceae), and the perennial herbs Krauseola mosambicina (Caryophyllaceae) and Spermacoce schlecteri (Rubiaceae). With increasing stabilisation species such as Apodytes dimidiata, Brachylaena discolor, Bridelia schlecteri, Clerodendron glabrum, Commiphora schlecteri, Ochna natalitia, Ozoroa obovata and Vepris lanceolata become more important. In some cases these have developed into dense evergreen forests rich in climbers and lianas such as Maclura africana, Popowia caffra, Rhoicissus revoilii, Sarcostemma viminale, Uvaria gracilipes and the endemic Cissus quadrangularis (Vitaceae), while other endemic species of these dune forests include the shrubs Allophylus mossambicensis (Sapindaceae) and Jatropha subaequiloba (Euphorbiaceae).

Zanzibar-Inhambane Coastal Sand Dunes (Malindi Bay, Kenya)

This active, prograding dune system includes transitions to more stabilized dunes. The area behind the active dune field is a complex fossil dune ridge system. However, parts of these dune are too dry to support vegetation. Even in this tropical humid climate dry conditions are experienced due to the high evaporation rates, which are almost double the annual precipitation rates. The following dune zones have been described.

Foredunes and Embryonic dunes
Foredunes are a distinctive feature. The main pioneer plants are Halopyrum mucronatum in the north and Ipomoea pes-caprae south of the Sabaki River, both of which are succulent species. With the latter companion species include Hermbstaedtia gregoryi and Scaevola plumieri. All the above species are also associated with deflation plains in the north where there scattered embryonic dunes.

Primary Dunes
These are largely colonised by shrubs but can be divided in to dunes characterised by the low shrub Cordia somaliensis and those dominated by the herbaceous Tephrosia purpurea. Other shrubs associated with Cordia somaliensis include Cadaba farinosa, Calotropis procera, Maytenus senegalensis and Pluchea discordi.These often form a single dense layer up to 5 m high which is usually infested with the parasitic vine Cassytha filiformis. The ground layer includes various shrubs such as Justicia flava and Sideroxylon inerme and grasses like Digitaria argyrotricha, D. gazensis and D. nuda. Other species associated with Tephrosia purpurea dunes include forbs such as Ipomoea pes-caprae and Macrotyloma uniflora and the grasses Digitaria argyrotricha and Eragrostis ciliaris.

Stabilized Hummock Dunes
The main species here is Cordia somaliensis but these dunes are also thickly vegetated with other shrubs such as Azima tetracantha, Phyllanthus reticulatus and Pluchea discoridis. Other less common shrubs include Achyranthes aspera, Commelina latifolia and Justicia flava. In the herbaceous layer Asystasia gangetica is the most abundant species, but graminoids such as Cenchrus biflorus, Digitaria argyrotricha, D. gazensis, D. nuda and Eragrostis ciliaris also occur. Also present are climbers such as Cissus rotundifolia, Jasminium fluminence and momordica rostrata.  

Dune Ridges
On the ridges of some of the more stabilized dunes relatively rich vegetation has developed often dominated by the shrub Cordia somaliensis.  Two communities have been identified – one characterised by Cordia somaliensis and Pluchea discoridis, the other by Achyranthes aspera and Justicia flava. The first is composed of medium to tall shrub with occasional trees. Other shrubs include Azima tetracantha, Deinbollia borbonica, Dichrostachys cinerea, Maytenus senegalensis, Phyllanthus reticulatus and Tricalysia ovalifolia. Typical trees mainly confined to the more sheltered zones include Afzelia cuanzensis, Drypetes natalensis, Garcinia livingstonei and Sideroxylon inerme. The second community is described as a herb layer beneath the Cordia somaliensis and Pluchea discoridis community. Other companion herbs include Asystasia gangetica, Boerhavia diffusa together with a few grasses such as Digitaria argyrotricha and Eragrostis ciliaris.

Dune Slacks
These low-lying depressions close to the water table are relatively species rich with most of the plant species being forbs or grasses. Two communities have been identified – one characterised by Tephrosia purpurea and Halopyrum mucronatum, the other by Pluchea discoridis and Portulaca parensis.   The first one occurs in areas where the water table is more than 0.5 m deep. The vegetation is xeromorphic in character and typically includes the grasses Digitaria argyrotricha and Eragrostis ciliaris. The latter community is typical of areas where the water table is less than 0.5 m. The shrub Pluchea discoridis mainly occurs south of the Sabaki River while the succulent herb Portulaca parensis is mainly north of the river. Other herbs include Alysicarpus glumaceus, Desmodium triflorum, Enicostema axillare, Hermbstaedtia gregoryi, Polygala sphenoptera and Stylosanthes fruticosa. Sedges such as Cyperus articulatus, C. rotundus, Fimbristylis cymosa, Pycreus polystachyos and Typha domigensis are also common.

Further information required.

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