Chap. 10, Vol. 1), these findings carry important implications for meeting the
sustainable development goals (SDGs) and especially SDG 15 “Life on land.”
Below, we discuss some important aspects related to reforestation (Sect. 9.4.2.1),
designation of protected areas (Sect. 9.4.2.2), and sustainable forest management
(Sect. 9.4.2.3).
9.4.2.1 Target Degraded Areas for Ecosystem Restoration
Our findings indicate that savannas have unique ecological functioning, based on
chronic disturbances (Sankaran et al. 2005). These savannas exist for millennia
(Salzmann and Hoelzmann 2005), but are currently threatened by recent land use
change, especially crop expansion and reforestation projects (Sect. 9.3.3). This is
often done because savannas are mistaken as degraded forests (Sect. 9.1), despite the
fact that they are alternative stable states to forest and are maintained through a
positive feedback between vegetation structure and fire events (Sect. 9.3.2).
Due to this mistaken view of mesic savannas being degraded forests, many
studies have suggested to target these savannas for forest restoration and tree
planting for carbon sequestration (Laestadius et al. 2012; WRI 2014; Chazdon and
Laestadius 2016). Even though many studies have suggested that the ecological
restoration of degraded savanna and forest landscapes can have substantial ecological benefits (Lamb et al. 2005; Buisson et al. 2019), it is important to focus
restoration efforts only to those areas that have actually been degraded, and are not
mistaken as such. This is particularly important in the context of SDG15, and
especially Target 15.2, where forest restoration is seen as an important intervention.
To this end, there is a need to develop integrated restoration frameworks that both
consider forest and savanna ecosystems, their respective ecological functioning, and
their long-term location and history. This could help avoid misrepresenting savannas
as degraded forest (Veldman et al. 2015a, c), and thus implementing restoration
interventions that could have counterproductive conservation outcomes. This would
require more retrospective studies to accurately reconstruct the past locations of
forests and savannas (Aleman et al. 2018).
In those cases where reforestation and forest restoration are deemed appropriate,
then it would be crucial to favor native species (Chazdon 2008; Doucet et al. 2016).
Indeed, exotic tree species such acacia and eucalypt currently dominate timber
plantations in central Africa, following a systematic replication of the same experimental design (Proces et al. 2017) (Chap. 10, Vol. 1).
9.4.2.2 Expand Protected Areas
Section 9.3.3 highlighted that protected areas in central Africa cover approximately
17.5% of tropical forests and 12.2% of savannas. According to the Aichi Biodiversity Target 11, 17% of terrestrial ecosystems need to be conserved through protected
areas by 2020. In this respect, it can be argued that the protection of savanna areas
9 Long-Term Vegetation Change in Central Africa: The Need for an Integrated. . .
303
sustainable development goals (SDGs) and especially SDG 15 “Life on land.”
Below, we discuss some important aspects related to reforestation (Sect. 9.4.2.1),
designation of protected areas (Sect. 9.4.2.2), and sustainable forest management
(Sect. 9.4.2.3).
9.4.2.1 Target Degraded Areas for Ecosystem Restoration
Our findings indicate that savannas have unique ecological functioning, based on
chronic disturbances (Sankaran et al. 2005). These savannas exist for millennia
(Salzmann and Hoelzmann 2005), but are currently threatened by recent land use
change, especially crop expansion and reforestation projects (Sect. 9.3.3). This is
often done because savannas are mistaken as degraded forests (Sect. 9.1), despite the
fact that they are alternative stable states to forest and are maintained through a
positive feedback between vegetation structure and fire events (Sect. 9.3.2).
Due to this mistaken view of mesic savannas being degraded forests, many
studies have suggested to target these savannas for forest restoration and tree
planting for carbon sequestration (Laestadius et al. 2012; WRI 2014; Chazdon and
Laestadius 2016). Even though many studies have suggested that the ecological
restoration of degraded savanna and forest landscapes can have substantial ecological benefits (Lamb et al. 2005; Buisson et al. 2019), it is important to focus
restoration efforts only to those areas that have actually been degraded, and are not
mistaken as such. This is particularly important in the context of SDG15, and
especially Target 15.2, where forest restoration is seen as an important intervention.
To this end, there is a need to develop integrated restoration frameworks that both
consider forest and savanna ecosystems, their respective ecological functioning, and
their long-term location and history. This could help avoid misrepresenting savannas
as degraded forest (Veldman et al. 2015a, c), and thus implementing restoration
interventions that could have counterproductive conservation outcomes. This would
require more retrospective studies to accurately reconstruct the past locations of
forests and savannas (Aleman et al. 2018).
In those cases where reforestation and forest restoration are deemed appropriate,
then it would be crucial to favor native species (Chazdon 2008; Doucet et al. 2016).
Indeed, exotic tree species such acacia and eucalypt currently dominate timber
plantations in central Africa, following a systematic replication of the same experimental design (Proces et al. 2017) (Chap. 10, Vol. 1).
9.4.2.2 Expand Protected Areas
Section 9.3.3 highlighted that protected areas in central Africa cover approximately
17.5% of tropical forests and 12.2% of savannas. According to the Aichi Biodiversity Target 11, 17% of terrestrial ecosystems need to be conserved through protected
areas by 2020. In this respect, it can be argued that the protection of savanna areas
9 Long-Term Vegetation Change in Central Africa: The Need for an Integrated. . .
303