Is Succession a Viable Concept in African Savanna Ecosystems?

Ecological and Human Community Resilience in Response to Natural Disasters

“…These scientists observe qualitative changes in both the structure and function of ecosystems (Gunderson 2000, Scheffer and Carpenter 2003 or the ecological regime or identity Salt 2006). Walker (1981) and Dublin et al (1990) found dramatic shifts between grass-dominated and shrub-dominated ecosystems in semi-arid rangelands that were mediated by interactions between herbivores, fires, and drought cycles. Scheffer and Carpenter (2003) described two alternative states (clear water with rooted aquatic vegetation and turbid water with phytoplankton) in shallow lake systems.…”

Resilience, Flexibility and Adaptive Management - - Antidotes for Spurious Certitude?

“…In this case, resilience is measured by the magnitude of disturbance that can be absorbed before the system redefines its structure by changing the variables and processes that control behavior. The second definition has been used to describe the dynamics of multiple-equilibria behavior of a variety of ecosystems, including freshwater rivers (Fiering 1982), freshwater lakes (Scheffer et al 1993, Carpenter andCottingham 1997), forests (Ludwig et al 1978), fisheries (Walters 1986), semiarid grasslands (Walker 1981), and interacting populations (Dublin et al 1990). …”

Evidence for climate-induced range shift in Brachystegia (miombo) woodland

“…54 Consequently, rather than relying on pollination and seed production, many climate relicts rely more strongly on vegetative or clonal reproduction. The well-documented reliance of B. spiciformis on coppice regrowth and root suckering, rather than seed germination, both at the Gundani relict 27 and in the continuous woodland 6 suggests that even in the event of failed recruitment through climatic intolerance, the populations would persist though vegetative reproduction and the longevity of genets. Relict populations can furthermore improve their survival prospects by enlarging their climatic tolerance through phenotypic plasticity or micro-evolutionary adaptation.…”

“…is the dominant component of miombo, the colloquial term used to describe sub-tropical woodlands dominated by Brachystegia, Julbernardia and Isoberlinia -three closely related genera in the family Fabaceae and subfamily Caesalpinioideae. 5 Miombo encompasses the woodland-dominated savanna ecosystems 6,7 which cover ( Figure 1) an estimated 2.7 million km 2 of south-central Africa 8 and is coincident with White's 9 Zambezian Phytochorion, the largest regional centre of endemism in Africa 10 . The dynamics of miombo woodland are largely determined by the woody component which, apart from climate, is predominantly influenced by people and fire.…”