emphasizes that ongoing global overexploitation of agricultural and forest ecosystems can lead to drastic decline or even loss of basic ecosystem services, such as
pollination or the regulation of pests. Thus, extensive management approaches and
restoration programmes can significantly contribute to multitrophic biodiversity
conservation and the future provisioning of ecosystem services.
The importance of biodiversity in maintaining multiple ecosystem functions and
services on which humans depend increases as more functions are considered
(ecosystem multifunctionality; Gamfeldt et al. 2008). Across biomes and spatial
scales, there is now increasing evidence that biodiversity enhances a multitude of
functions that forest ecosystems simultaneously provide for human well-being
(Gamfeldt et al. 2013; van der Plas et al. 2016; Ratcliffe et al. 2017; Schuldt et al.
2018; van der Plas et al. 2018). Promoting high levels of multiple ecosystem services
therefore requires conservation and restoration measures within and among ecological communities, as well as measures for less prominent taxa, such as soil
microorganisms. Although often overlooked, belowground biodiversity is an important component of terrestrial biodiversity accounting for roughly 25% of global
biodiversity (George et al. 2019). Soil biota play a vital functional role in the
provisioning of ecosystem services, such as nutrient cycling or carbon storage
(Bardgett and van der Putten 2014; Adhikari and Hartemink 2016). Above- and
belowground forest biodiversity is not always closely related and its ratio depends on
the biome. For example, the tropical and subtropical moist broadleaf forests biome is
a biodiversity hotspot both above- and belowground. Contrarily, the temperate
broadleaf and mixed forests biome contain more species aboveground, while the
opposite holds for boreal and tundra biomes (Cameron et al. 2019). Accounting for
soil biodiversity—particularly in boreal, subtropical and tropical forest ecosystems—appears therefore crucial to ensure the reliable provision of ecosystem services. These examples illustrate the functional importance of forest biodiversity and
emphasize the vital importance of safeguarding forest biodiversity across trophic
levels for future human well-being.
4.2 Linking Biodiversity and Ecological Continuity of Forest
Ecosystems
Disruption of ecological continuity due to land-use change or land-use intensification can trigger biodiversity loss, and thereby changes in ecosystem functioning.
Here, we use the term ‘ecological continuity’ in an ecosystem-based sense, meaning
the continuity in biotic and abiotic forest ecosystem processes that develop without
land-use change, forest management or significant silvicultural interventions. A long
ecological continuity is therefore commonly associated with a high integrity in
habitat structures, species composition, species interactions, soil conditions and
biogeochemical cycles typical for a given forest type. Importantly, ecological continuity refers to three different aspects that determine how forests mature: forest
Forest Ecosystems: A Functional and Biodiversity Perspective
393
pollination or the regulation of pests. Thus, extensive management approaches and
restoration programmes can significantly contribute to multitrophic biodiversity
conservation and the future provisioning of ecosystem services.
The importance of biodiversity in maintaining multiple ecosystem functions and
services on which humans depend increases as more functions are considered
(ecosystem multifunctionality; Gamfeldt et al. 2008). Across biomes and spatial
scales, there is now increasing evidence that biodiversity enhances a multitude of
functions that forest ecosystems simultaneously provide for human well-being
(Gamfeldt et al. 2013; van der Plas et al. 2016; Ratcliffe et al. 2017; Schuldt et al.
2018; van der Plas et al. 2018). Promoting high levels of multiple ecosystem services
therefore requires conservation and restoration measures within and among ecological communities, as well as measures for less prominent taxa, such as soil
microorganisms. Although often overlooked, belowground biodiversity is an important component of terrestrial biodiversity accounting for roughly 25% of global
biodiversity (George et al. 2019). Soil biota play a vital functional role in the
provisioning of ecosystem services, such as nutrient cycling or carbon storage
(Bardgett and van der Putten 2014; Adhikari and Hartemink 2016). Above- and
belowground forest biodiversity is not always closely related and its ratio depends on
the biome. For example, the tropical and subtropical moist broadleaf forests biome is
a biodiversity hotspot both above- and belowground. Contrarily, the temperate
broadleaf and mixed forests biome contain more species aboveground, while the
opposite holds for boreal and tundra biomes (Cameron et al. 2019). Accounting for
soil biodiversity—particularly in boreal, subtropical and tropical forest ecosystems—appears therefore crucial to ensure the reliable provision of ecosystem services. These examples illustrate the functional importance of forest biodiversity and
emphasize the vital importance of safeguarding forest biodiversity across trophic
levels for future human well-being.
4.2 Linking Biodiversity and Ecological Continuity of Forest
Ecosystems
Disruption of ecological continuity due to land-use change or land-use intensification can trigger biodiversity loss, and thereby changes in ecosystem functioning.
Here, we use the term ‘ecological continuity’ in an ecosystem-based sense, meaning
the continuity in biotic and abiotic forest ecosystem processes that develop without
land-use change, forest management or significant silvicultural interventions. A long
ecological continuity is therefore commonly associated with a high integrity in
habitat structures, species composition, species interactions, soil conditions and
biogeochemical cycles typical for a given forest type. Importantly, ecological continuity refers to three different aspects that determine how forests mature: forest
Forest Ecosystems: A Functional and Biodiversity Perspective
393