Citation: Sandvik, H., and B.-E. Sæther (2012)
Kriterier og metoder for kartlegging og overvåkning av fremmede arter
[Criteria and methods for monitoring and surveillance of alien species
(in Norwegian with English abstract)].
Utredning for Direktoratet for naturforvaltning,
Key words: Alien species, invasion biology, monitoring,
prioritisation, sampling design, surveillance.
Abstract: There is a great need for dedicated monitoring
programs of alien species in Norway. The development of such programs hinges
on criteria to identify and prioritise the species to be monitored, and on
an appropriate and standardised method. This report summarises the state of
knowledge in this area and derives a few recommendations.
The state of knowledge in comparative invasion biology
– both internationally and particularly in
Norway – is still too poor to develop a well-founded set of
morphological, physiological, ecological or demographic selection criteria for
the monitoring of alien species. For the time being, prioritisation of monitoring
efforts should thus be based on the experience with invasive species in other
countries. This information should be combined with knowledge about the
species’ spread potential in Norway and their ecological risk category
according to the Norwegian classification system of alien species.
In carrying out the monitoring programs, it is essential that
detection rates are high, that monitoring effort is as constant as possible
and that both positive and negative findings are reported. This entails that
(1) a network of monitoring plots should be established along transects;
(2) the monitoring plots are not switched or discontinued after establishment;
(3) monitoring effort must vary as little as possible through space and time;
(4) monitoring effort should be quantified. Monitoring plots for an early
warning system should not be arranged along transects but as a fixed grid
in prioritised areas. The data to be sampled are population counts (rather
than mere presence/absence data) of both the alien and relevant native
species as well as relevant abiotic environmental factors.
Full text: © 2012 The Norwegian Directorate for Nature
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the report here (pdf, 1.2 MB).