In general, the impact of invasive species is stronger where functional roles have
not been occupied by native species during their evolutionary history. For example,
bird species on islands became extirpated by introduced animals such as rats, cats,
goats, and snakes simply because the native, often ground-breeding birds had no
experience with such aggressive predators in their evolutionary history. In all these
cases, competition was not the problem, or of minor importance; the occupation of a
niche by an alien species, which was not occupied before, was the main reason.
Therefore, the situation on islands has to be assessed and evaluated in a different way
in comparison to most mainland regions.
In the case of hyperendemics and local endemics, it is possible to distinguish
between species living in mainland regions and on islands. In general, invasive and
other problematic species, geological events and severe weather are more problematic on islands than in mainland regions.
Pollution including industrial and domestic wastewater, washout of fertilizers,
hormones, pesticides and other chemical components has a strong impact on plants
and animals living in humid, wet or inundated habitats, and in mainland regions. Dry
habitats such as desert or semi-desert, and island habitats are often not affected in the
same way.
Climate change and severe weather may augment the existing impacts of land use
change, and can affect many habitat types and associated biota in the long-run if
trends persist. East Asia, for example, is characterized by high species richness and
endemism. However, logging, agricultural conversion, and the dramatic transformation of natural landscapes into urbanized areas are the most direct threats to biodiversity. Similarly, because of the over-harvesting of wild medicinal plants, local
extinction of species has become common in East Asia and parts of Africa. These
threats have likewise meant lost opportunities for phytomedical research and the
mobilisation of new medicines.
In view of the potential effects of global climate change on biodiversity, many
narrow endemic species in East Asia and other parts of the world are threatened with
extinction, as they are unlikely to be able to adapt to new conditions, or to disperse to
new favourable habitats in the anticipated time period of change. In general, the
combination of distributional, genetic, biological and ecological information must be
utilized to conserve endemic and threatened species.
5.2 Habitat Types, Ecological Requirements
and Consequences
One of the best ways to protect biodiversity at global scales is to protect habitats as
living spaces with respect to ecosystem functioning, including natural food webs.
Forest, shrubland and freshwater habitats harbour the majority of critically
endangered species on Earth. However, the level of endangerment among habitats
and associated species differs considerably from region to region. For example, in E
470
C. Hobohm et al.
not been occupied by native species during their evolutionary history. For example,
bird species on islands became extirpated by introduced animals such as rats, cats,
goats, and snakes simply because the native, often ground-breeding birds had no
experience with such aggressive predators in their evolutionary history. In all these
cases, competition was not the problem, or of minor importance; the occupation of a
niche by an alien species, which was not occupied before, was the main reason.
Therefore, the situation on islands has to be assessed and evaluated in a different way
in comparison to most mainland regions.
In the case of hyperendemics and local endemics, it is possible to distinguish
between species living in mainland regions and on islands. In general, invasive and
other problematic species, geological events and severe weather are more problematic on islands than in mainland regions.
Pollution including industrial and domestic wastewater, washout of fertilizers,
hormones, pesticides and other chemical components has a strong impact on plants
and animals living in humid, wet or inundated habitats, and in mainland regions. Dry
habitats such as desert or semi-desert, and island habitats are often not affected in the
same way.
Climate change and severe weather may augment the existing impacts of land use
change, and can affect many habitat types and associated biota in the long-run if
trends persist. East Asia, for example, is characterized by high species richness and
endemism. However, logging, agricultural conversion, and the dramatic transformation of natural landscapes into urbanized areas are the most direct threats to biodiversity. Similarly, because of the over-harvesting of wild medicinal plants, local
extinction of species has become common in East Asia and parts of Africa. These
threats have likewise meant lost opportunities for phytomedical research and the
mobilisation of new medicines.
In view of the potential effects of global climate change on biodiversity, many
narrow endemic species in East Asia and other parts of the world are threatened with
extinction, as they are unlikely to be able to adapt to new conditions, or to disperse to
new favourable habitats in the anticipated time period of change. In general, the
combination of distributional, genetic, biological and ecological information must be
utilized to conserve endemic and threatened species.
5.2 Habitat Types, Ecological Requirements
and Consequences
One of the best ways to protect biodiversity at global scales is to protect habitats as
living spaces with respect to ecosystem functioning, including natural food webs.
Forest, shrubland and freshwater habitats harbour the majority of critically
endangered species on Earth. However, the level of endangerment among habitats
and associated species differs considerably from region to region. For example, in E
470
C. Hobohm et al.