Alien Species.vp - IUCN

At least some invasive species of plants may themselves be considered as a health hazard in
both temperate and tropical regions. Binggeli (this volume) reports that large quantities of airborne
pollen of Casuarina equisetifolia cause respiratory irritations. In the close vicinity of
habitations, both Schinus terebinthifolius and Melaleuca quinquenervia appear to cause
respiratory difficulties in many people, and skin contact with leaves and the sap of S.
terebinthifolius results in red, itching rashes.
The dynamism among invasive pathogens, human behaviour, and economic development
are complex and depend on interactions between the virulence of the disease, infected and
susceptible populations, the pattern of human settlements, and their level of development.
Large development projects, such as dams, irrigation schemes, land reclamation, road
construction and population resettlement programmes, have contributed to the invasion of
diseases such as malaria, dengue, schistosomiasis and trypanosomiasis. The clearing of forests
in tropical regions to extend agricultural land has opened up new possibilities for wider
transmission of viruses that carry haemorrhagic fevers that previously circulated benignly in
wild animal hosts. Invasive species combined with variations in inter-annual rainfall,
temperature, human population density, population mobility and pesticide use all contribute to
one of the most profound human dimensions of invasive species: the threat to human health.
Components of biological diversity that are threatened or lost as a result of IAS can lead to
the loss of traditional knowledge, innovations and practices. Likewise, customary uses of
biological resources in accordance with traditional cultural practices may be inhibited or, in the
worst case, discontinued completely. As intimate users of local biological resources,
indigenous and local communities potentially are best-qualified to monitor the impacts of alien
species on local ecosystems and their components (Article 7 of the Convention on Biological
Diversity), to identify when those species become invasive, and to be involved in eradication
and mitigation programmes (Article 8h of the CBD). But this depends on awareness of the
problem. In China, Vietnam, Malaysia, Thailand, Korea, and Cambodia (at least), people
“make merit” by releasing captive animals, especially birds, fish, and turtles; but one study in
Taiwan found that 6% of birds released were exotic, and most of the fish and turtles were
captive-bred exotic species that could become invasive (Severinghaus and Chi, 1999). Clearly,
the cultural process of “making merit” does not intentionally include deleterious impacts on
native ecosystems, but occurs largely because the people involved have no concept of IAS.
Human dimensions of the response to IAS
This book says relatively little about the actual management of IAS, leaving that important
topic in the hands of other contributors to GISP (GISP, 2000). But generally speaking, GISP
advocates four main management approaches: first, subject all alien species proposed for
introduction to expert consideration, following the precautionary principle; second, improve
the scientific basis for predicting which species proposed for deliberate introduction are likely
to become invasive and which are likely to be beneficial; third, improve control of pathways for
unplanned introductions (through ballast water, international trade, wooden packing material,
and so forth); and fourth, improve management techniques to eradicate or control invasive alien
species once prevention has failed or become impractical.
Human societies seem to have a great capacity for contradiction, with quarantine
inspections, for example, being the responsibility of the same governments that promote
globalization that undermines government capacity to apply effective quarantine measures
(Low, this volume). Governments have a responsibility to provide regulations in the public
interest, but current economic orthodoxy argues that global trade is fostered through removing
regulations that may constrain such trade, such as restrictions that may prevent the introduction
of a potentially invasive alien species. These contradictions help to underline the conflict of
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Human dimensions of invasive alien species