Status of the Mara Woodlands in Kenya

Abstract

The woodlands of the Masai Mara National Reserve in Kenya have suffered dramatic declines over four decades as a result of elephant and fire pressure. This study examined the current status of woody resources in the Reserve and browse pressure thereon, using both classification (TWIN-SPAN) and ordination (DCA) techniques. From 333 widespread regular plots used to survey the vegetation, a total of 62 woody species were identified. Thirteen woody habitats were identified on the basis of species composition, varying from species-rich closed thickets and forest to less diverse open grasslands. A NW/SE stratification of the more open habitats was observed, possibly as a result of differences in soils, rainfall and drainage. Both plant density and diversity were lower than in communal and privately managed areas outside the Reserve. Moreover, browser pressure was substantially higher than that observed previously in the ecosystem, and suggests increased competition for scarcer woody resources within the Reserve. This has implications for the management of the ecosystem as a whole. As woodland and thickets continue to decline, long-term monitoring should expand to encompass the wider habitat diversity of the open grasslands and unprotected areas where much of the regeneration potential resides. RésuméLes forêts de la Réserve Nationale de Masai Mara, au Kenya, ont subi des réductions dramatiques depuis quatre décennies, suite à la pression des éléphants et des feux. Cette étude a examiné le statut actuel des ressources en bois dans la Réserve et la pression du pâturage qui s'y ajoute, en utilisant les techniques de classification (TWINSPAN) et d'ordination (DCA). Dans 333 plots rég-ulièrement dispersés, utilisés pour étudier la végétation, on a identifié 62 espèces ligneuses. On a identifié aussi 13 habitats forestiers sur la base de la composition des espèces, depuis les buissons et les forêts fermés riches en espèces jusqu'aux prairies ouvertes moins diverses. On a observé une stratification NO/SE dans les habitats plus ouverts, résultat peut-être de différences de sols, de chutes de pluies et de drainage. La densité et la diversité des plantes étaient plus faibles que dans les aires gérées en commun ou de façon privée en dehors de la Réserve. Qui plus est, la pression des animaux qui mangent les buissons y était substantiellement plus élevée que celle qu'on observait jadis dans cet écosystème, et elle laisse penser qu'il y a une compétition plus forte pour des ressources ligneuses plus rares dans la Réserve. Ceci a des implications pour la gestion de l'écosystème dans son ensemble. Si les forêts et les buissons continuent à se rèduire, le monitoring à long terme devrait s'élargir pour englober la plus grande diversité d'habitat des prairies ouvertes et des aires non protégées où réside l'essentiel du potentiel de régénération.

Aboveground biomass and leaf area index (LAI) mapping for Niassa Reserve, northern Mozambique

“…The limited work conducted in the miombo region indicates that fire and elephants together act as a powerful restriction on the recruitment of trees. This ultimately decreases woody vegetation productivity [ Guy , 1981, 1989; Ben‐Shahar , 1998; Mapaure and Campbell , 2002; Walpole et al , 2004; Baxter and Getz , 2005; Ribeiro , 2007; Ribeiro et al , 2008], with consequences for carbon and energy balances [ Houghton , 2005].…”

Remote Sensing of Biomass in the Miombo Woodlands of Southern Africa: Opportunities and Limitations for Research

“…Changes in the landscape of many types of woodland in Africa have been attributed directly to the interactive effect of elephants and fire (Buechner & Dawkins, 1961;Guy, 1981Guy, , 1989Laws, 1970;Mapaure & Campbell, 2002;Ribeiro et al, 2008a;Sukumar, 2003;Walpole et al, 2004). In general, the pattern of change is the same: as elephants over-browse the woodlands, laying waste to mature trees, there is an increase in the low woody vegetation and grass cover as well as a dramatic increase in fuel load.…”

“…Dublin et al (1990) studied the effects of elephants and fires in the Serengeti-Mara woodlands in Kenya and found that the combined effect of fire and elephants caused consistently decrease in the recruitment of tree species. Recently Walpole et al (2004) assessed the status of the Mara woodlands (adjacent to the Serengeti National Park). They report that species diversity is relatively low, possibly because of decline in the density and extent of woodland and thickets originated by increasing elephant population within the area.…”

Woody Vegetation Utilisation in Tembe Elephant Park, Kwazulu-Natal, South Africa

“…In Ithala, the combination of elephants and browsers pressure was such that plant species composition changed from species with climax state lifecycle traits (long lived, low recruitment) to more pioneer like species (high recruitment, shorter lifespans ) and also promoted the recruitment of less desirable browse species (Wiseman et al, 2004). Other studies have shown that small mammals herbivory is usually not a limiting factor on its own, although it slows regeneration in cases of high densities (Barnes, 2001;Walpole et al, 2004;Western & Maitumo, 2004;Western, 2006). In Kenya's Masaai Mara National Reserve, 73% of woody species were utilised by small browsers, which changed species composition and abundance andfacilitated some invasive species (Walpole et al, 2004).…”

“…Other studies have shown that small mammals herbivory is usually not a limiting factor on its own, although it slows regeneration in cases of high densities (Barnes, 2001;Walpole et al, 2004;Western & Maitumo, 2004;Western, 2006). In Kenya's Masaai Mara National Reserve, 73% of woody species were utilised by small browsers, which changed species composition and abundance andfacilitated some invasive species (Walpole et al, 2004). In Botswana, small to medium browsers were considered responsible for changing vegetation morphology (Styles & Skinner, 2001).…”