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8.1 Key Concepts
In this chapter we take a closer look at one of the central concepts of this book,
biodiversity, and especially at the way it is defined. We do so because the definition
of this concept has a bearing on what to measure, how best to measure it, and how
to study its relationship to other concepts, such as mental health and well-being. The
latter concepts are also discussed, but only briefly.
8.1.1 Biodiversity
These days, the term ‘biodiversity’ is often interpreted and used by conservationists,
policy-makers and the general public as an alternative for the broader term ‘nature’,
more or less suggesting that they are interchangeable (Kaphengst et al. 2014; for
examples, see Wossink et al. 1997; Wall et al. 2016, Chap. 4). ‘Biodiversity’, however, originates from the scientific fields of ecology and nature conservation, and
there it has a much stricter meaning. Here we start from this original meaning in
which biodiversity – as defined by the Convention on Biological Diversity (CBD
1992) – is the variability among living organisms and the ecological complexes of
which they are part. Sources of this variability include intra-species diversity (e.g.
genetic variability), interspecies diversity (species diversity) and diversity in ecosystems (from biomes to biotopes). Although biodiversity encompasses these three
levels of variability, in relationship to human health the species diversity level seems
to be the most studied level thus far (Lovell et al. 2014; see also Marselle et al.
Chap. 9, this volume). To confine the discussion, in this chapter we therefore focus
on this level.
An initial question is whether species are required to be part of an ecological
complex, and if so, what counts as such a complex. We equate the term ‘ecological
complex’ with ‘ecosystem’, for which the CBD (1992) also has provided a definition: a dynamic complex of plant, animal and micro-organism communities and
their non-living environment interacting as a functional unit. Some authors include
humans as a possible species within an ecosystem. In this chapter, we do not. Given
the requirement of interacting as a functional unit and the exclusion of humans,
although a zoo contains many animal species, it can hardly be considered an ecosystem. The same holds true for a hortus botanicus or arboretum. With regard to species, Angermeier (1994) already made a distinction between biodiversity and
artificial diversity.
To a lesser extent, urban parks and private gardens may also contain combinations of plants and animals that do not occur in that composition in a (natural) ecosystem, many of which may not be indigenous to the area. Non-indigenous plants
include (wild) ornamental trees, shrubs, perennials and garden pond plants. Nonindigenous animals include (feral) cats, dogs, aviary birds and other pet species. The
living nature that parks and gardens contain usually is not intended or allowed to
S. de Vries and R. Snep
8.1 Key Concepts
In this chapter we take a closer look at one of the central concepts of this book,
biodiversity, and especially at the way it is defined. We do so because the definition
of this concept has a bearing on what to measure, how best to measure it, and how
to study its relationship to other concepts, such as mental health and well-being. The
latter concepts are also discussed, but only briefly.
8.1.1 Biodiversity
These days, the term ‘biodiversity’ is often interpreted and used by conservationists,
policy-makers and the general public as an alternative for the broader term ‘nature’,
more or less suggesting that they are interchangeable (Kaphengst et al. 2014; for
examples, see Wossink et al. 1997; Wall et al. 2016, Chap. 4). ‘Biodiversity’, however, originates from the scientific fields of ecology and nature conservation, and
there it has a much stricter meaning. Here we start from this original meaning in
which biodiversity – as defined by the Convention on Biological Diversity (CBD
1992) – is the variability among living organisms and the ecological complexes of
which they are part. Sources of this variability include intra-species diversity (e.g.
genetic variability), interspecies diversity (species diversity) and diversity in ecosystems (from biomes to biotopes). Although biodiversity encompasses these three
levels of variability, in relationship to human health the species diversity level seems
to be the most studied level thus far (Lovell et al. 2014; see also Marselle et al.
Chap. 9, this volume). To confine the discussion, in this chapter we therefore focus
on this level.
An initial question is whether species are required to be part of an ecological
complex, and if so, what counts as such a complex. We equate the term ‘ecological
complex’ with ‘ecosystem’, for which the CBD (1992) also has provided a definition: a dynamic complex of plant, animal and micro-organism communities and
their non-living environment interacting as a functional unit. Some authors include
humans as a possible species within an ecosystem. In this chapter, we do not. Given
the requirement of interacting as a functional unit and the exclusion of humans,
although a zoo contains many animal species, it can hardly be considered an ecosystem. The same holds true for a hortus botanicus or arboretum. With regard to species, Angermeier (1994) already made a distinction between biodiversity and
artificial diversity.
To a lesser extent, urban parks and private gardens may also contain combinations of plants and animals that do not occur in that composition in a (natural) ecosystem, many of which may not be indigenous to the area. Non-indigenous plants
include (wild) ornamental trees, shrubs, perennials and garden pond plants. Nonindigenous animals include (feral) cats, dogs, aviary birds and other pet species. The
living nature that parks and gardens contain usually is not intended or allowed to
S. de Vries and R. Snep