savannas as dry forests
3 (Bond and Zaloumis 2016; Griffith et al. 2017). The above
suggest that the FAO definition of forest is problematic, as most mesic savannas
would be consequently considered as forests (more specifically degraded forests),
and could thus be targeted for reforestation (Laestadius et al. 2012).
For example, the Miombo woodlands that cover much of southern Africa has
been identified as a particular ecoregion (Olson et al. 2001), and is considered as
forest by Bastin et al. (2017) or other type of woodland by Achard et al. (2014).
However, Miombo woodlands in which trees are widely spaced and do not form a
closed canopy cover are associated to the savanna flora (Linder 2014). They are also
associated to the savanna biome as they have a grassy understory and experience
regular fires (Ratnam et al. 2011; Dexter et al. 2015; Pennington et al. 2018). The
Miombo woodlands host a high floristic richness and specificity, and are dominated
by species of the Brachystegia, Julbernardia, and Isoberlinia genera (White 1983).
They also provide many different types of natural resources and ecosystem services
such as timber products, fuelwood, and a huge variety of non-timber forest products
including beeswax and honey, mushrooms, edible caterpillars, wild fruits, and
livestock grazing (Lawton 1982; Malaisse 2010) (see Chap. 5, Vol. 2). With millions
of people living in (and depending on) the Miombo woodlands (Bradley and
McNamara 1993; Dewees 1994), these landscapes are heavily affected by human
activity and are under threat from increasing fragmentation and deforestation
(Chazdon 2008).
The above suggests that forests and savannas are both two very important tropical
biomes in SSA and face the new threats posed by the Anthropocene. Land use
change (e.g., conversion to agriculture in forest areas, and industrial plantations in
savanna areas) and mismanagement (e.g., extensive logging and woodfuel
harvesting, uncontrolled fire regimes) threaten biodiversity and ecosystem services
from these biomes. Furthermore, they can compromise the critical role that tropical
forests and savannas play for local livelihoods and global climate regulation.
In this respect the loss of tropical forests and savannas and the need for their
effective management have become major sustainability challenges in SSA, and
especially in central Africa. In particular, there is a need for their integrated management, taking into account that they can be alternative stable states in some areas
(i.e., under intermediate rainfall) (Staver et al. 2011a; Favier et al. 2012), and that
savannas are not simply degraded forests only useful for reforestation and afforestation projects. In this context, it is important to identify the appropriate management
responses to the drivers of vegetation change in forests and savannas of central
Africa.
The aim of this chapter is to provide a comprehensive analysis of the past,
present, and future vegetation changes in central African forests and savannas. We
focus particularly on historical and future changes related to climate change and land
3 Tropical dry forests are an important biome in the Neotropics, the third tropical biome (Dexter
et al. 2018). However in SSA tropical dry forests are supposed to be restricted only to a very small
area in East Africa (Pennington et al. 2018).
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J. C. Aleman and A. Fayolle
3 (Bond and Zaloumis 2016; Griffith et al. 2017). The above
suggest that the FAO definition of forest is problematic, as most mesic savannas
would be consequently considered as forests (more specifically degraded forests),
and could thus be targeted for reforestation (Laestadius et al. 2012).
For example, the Miombo woodlands that cover much of southern Africa has
been identified as a particular ecoregion (Olson et al. 2001), and is considered as
forest by Bastin et al. (2017) or other type of woodland by Achard et al. (2014).
However, Miombo woodlands in which trees are widely spaced and do not form a
closed canopy cover are associated to the savanna flora (Linder 2014). They are also
associated to the savanna biome as they have a grassy understory and experience
regular fires (Ratnam et al. 2011; Dexter et al. 2015; Pennington et al. 2018). The
Miombo woodlands host a high floristic richness and specificity, and are dominated
by species of the Brachystegia, Julbernardia, and Isoberlinia genera (White 1983).
They also provide many different types of natural resources and ecosystem services
such as timber products, fuelwood, and a huge variety of non-timber forest products
including beeswax and honey, mushrooms, edible caterpillars, wild fruits, and
livestock grazing (Lawton 1982; Malaisse 2010) (see Chap. 5, Vol. 2). With millions
of people living in (and depending on) the Miombo woodlands (Bradley and
McNamara 1993; Dewees 1994), these landscapes are heavily affected by human
activity and are under threat from increasing fragmentation and deforestation
(Chazdon 2008).
The above suggests that forests and savannas are both two very important tropical
biomes in SSA and face the new threats posed by the Anthropocene. Land use
change (e.g., conversion to agriculture in forest areas, and industrial plantations in
savanna areas) and mismanagement (e.g., extensive logging and woodfuel
harvesting, uncontrolled fire regimes) threaten biodiversity and ecosystem services
from these biomes. Furthermore, they can compromise the critical role that tropical
forests and savannas play for local livelihoods and global climate regulation.
In this respect the loss of tropical forests and savannas and the need for their
effective management have become major sustainability challenges in SSA, and
especially in central Africa. In particular, there is a need for their integrated management, taking into account that they can be alternative stable states in some areas
(i.e., under intermediate rainfall) (Staver et al. 2011a; Favier et al. 2012), and that
savannas are not simply degraded forests only useful for reforestation and afforestation projects. In this context, it is important to identify the appropriate management
responses to the drivers of vegetation change in forests and savannas of central
Africa.
The aim of this chapter is to provide a comprehensive analysis of the past,
present, and future vegetation changes in central African forests and savannas. We
focus particularly on historical and future changes related to climate change and land
3 Tropical dry forests are an important biome in the Neotropics, the third tropical biome (Dexter
et al. 2018). However in SSA tropical dry forests are supposed to be restricted only to a very small
area in East Africa (Pennington et al. 2018).
284
J. C. Aleman and A. Fayolle