Implementation of threat levels in legislation

In view of the vulnerability of bryophytes to extinction, a logical step beyond the recognition of highly threatened taxa is the implementation of threat levels into the legislation. Although the degree of legal protection remains very low, bryophyte species have increasingly been included in legal texts regulating the collection of selected species (e.g. the Swiss Nature and Landscape Protection Decree, Appendix 2, www.admin.ch/ch/f/rs/451_1/index.html; the Canadian

Box 10.1 The IUCN categories in brief

In the IUCN classification system, species are ranked into seven categories. Species that belong to either the Extinct, Critically Endangered or Endangered categories, can be termed 'threatened' (Box 10.1 Fig. 1). A brief, simplified description of these categories is provided below (see IUCN 2001, for more details).

Box 10.1 Fig. 1. Hierarchical diagram of the IUCN threat categories.

Extinct (EX): A taxon is Extinct when there is no reasonable doubt that the last individual has died. For bryophytes, a species is considered EX when it has not been seen for the last 50 years throughout its entire distribution range (EX) or in part of it, in which case the taxon can be included in the Regionally Extinct category (RE). Alternatively, the taxon must be confined to sites, which have been thoroughly surveyed without success in recent years, or where suitable habitat has disappeared.

Critically Endangered (CR) corresponds to a > 50% risk of extinction in 10 years or 3 generations. For bryophytes, the criterion based on the distribution area (AOO, see Table 10.1 for details) is most easy to use. The taxon must be known from a single or several severely fragmented locations* covering altogether < 10 km2 and experience a continuing decline. Decline in habitat size or quality is most often used as a surrogate for actual population decline in the abscence of data on population trends.

Endangered (EN) corresponds to a risk of extinction > 20% in 20 years or 5 generations. The AOO must be < 500 km2. In addition, the taxon must be known from < 5 locations* and also have experienced a continuing decline.

Vulnerable (VU) corresponds to a risk of extinction > 10% in 100 years. The AOO must be < 2000 km2. In addition, the taxon must be known from < 10 locations* and have experienced a continuing decline.

Data Deficient (DD) is applied to taxa with insufficient data to categorize them, but which are thought likely to qualify as Extinct, Critically Endangered, Endangered or Vulnerable when they are better known. Near Threatened (NT): A taxon is NT when it is close to qualifying for VU. Least Concern (LC) is applied to taxa that do not qualify (and are not close to qualifying) as threatened or near threatened.

Note:

*The term 'location' defines a geographically or ecologically distinct area in which a single threatening event can rapidly affect all individuals of the taxon present (IUCN 2001).

Fig. 10.1. Bryophyte species frequency distribution in 87 4 x 4 km grid-squares in an area of southern Belgium, showing a typical skewed-shape (reproduced from Vanderpoorten & Engels 2003 with permission of Springer).

Species at Risk Act (Mcintosh & Miles 2005); the European Annex V of the Habitats Directive, ec.europa.eu/environment/nature/nature_conservation/ eu_nature_legislation/habitats_directive/index_en.htm; and Schedule 8 of the British Wildlife and Countryside Act 1981, www.jncc.gov.uk/). In the European Union for example, the habitats of 32 threatened bryophyte species are protected under Annex II of the Habitats Directive, which has already led

■ threatened ■ extinct mosses ■ threatened liverworts • extinct liverworts

Fig. 10.2. Proportion of extinct and threatened (sensu IUCN) moss and liverwort species in the bryophyte flora of selected countries and areas. Threatened species correspond to the categories 'critically endangered', 'endangered' and 'vulnerable' of IUCN (Box 10.1) (data from Vanderpoorten & Hallingback 2009).

■ threatened ■ extinct mosses ■ threatened liverworts • extinct liverworts

Fig. 10.2. Proportion of extinct and threatened (sensu IUCN) moss and liverwort species in the bryophyte flora of selected countries and areas. Threatened species correspond to the categories 'critically endangered', 'endangered' and 'vulnerable' of IUCN (Box 10.1) (data from Vanderpoorten & Hallingback 2009).

to the protection of more than 1000 localities included in the Natura 2000 network (Hallingbäck 2003). Similarly, in the UK, bryophytes may be included within a Site of Special Scientific Interest (SSSI) and guidelines have been produced to aid the selection of SSSI on the basis of the sum of species threat levels, as defined in the British Red Data Book (www.jncc.gov.uk/).

Was this article helpful?

0 0
Weight Loss Funnel

Weight Loss Funnel

Who Else Wants To Discover The 3 Most Effective Fat Burning Methods The Weight Loss Industry Does NOT Want You To Know About.

Get My Free Ebook


Post a comment