Red and Blue Lists

A fundamental tool used in the effort to evaluate global biodiversity conditions is that of the Red Lists, databases continuously updated which designate animal and plant species rare or threatened with extinction. Thanks to the inventory of endangered species and the analysis of reasons that caused their numerical decline, these lists constitute the starting point for the elaboration of better adapted strategies for nature protection in a more efficient way.

Very useful, not only at a scientific but also at a legislative level, Red Lists are the sentinels that provide information on species rare and threatened with extinction. Nevertheless, biodiversity conservation has to be conducted on the basis of other parameters (e.g.: cost, logistics, possibility of success) in order to achieve the protection of communities, micro-habitats and ecosystems as a whole, rather than the protection of only one species (Image: 2004 IUCN Red List of Threatened Species ).

 

Red Lists are elaborated at a regional and national level by institutions that deal with nature protection or with research, such as parks and universities, and, at the global level, they are represented by organisations such as IUCN (International Union for the Conservation of Nature) that work at establishing them.

The Red List of Threatened Species , published by IUCN, is prepared by its Species Survival Commission. It is a practical and educational tool, compiled with the assistance of world scientists and specialists. This Red List is considered as the most objective and important resource for learning about species threatened with extinction at a global level (Lamoreux et al. 2003, Hambler 2004; in Butchart et al. 2004); it not only provides general taxonomic information but also other very useful information about conservation issues, such as:

- risk level of a species;

- threat factors for a species;

- endangered species in a certain country.



In this database , the species are subdivided into categories that permit the classification of all plant and animal species (except for micro-organisms) according to their risk of extinction at a global level at the present moment. The IUCN categories, many years ago by the international scientific community, have been recently modified for creating a more objective and explicit system. The nine categories actually adopted (Version 3.1: IUCN - 2001), which can be used, after a brief update, for the preparation of Red Lists at a regional, national or local level, are the following:

 

EX (Extinct); EW (Extinct in the Wild); CR (Critically Endangered); EN (Endangered); VU (Vulnerable); NT (Near Threatened); LC (Least Concern); DD (Data Deficient); NE (Not Evaluated).

A species can be assigned to one of the three threatened categories (CR, EN, VU), provided that it meets one of the five following quantitative criteria;

A. Reduction in its population size (past, present and/or estimated);

B. Area of distribution of the population estimated to be less than 100km2 (5000 km2, 20.000 km2) or colonized part of the area estimated to be less than 10 km2 (500 km2, 2000 km2) and: fragmentation, reduction or fluctuation;

C. Population size reduced and estimated to number fewer than 250 mature individuals (2.500, 10.000) and: fragmentation, reduction or fluctuation;

D. Population size very reduced and estimated to number fewer than 50 mature individuals (25-, 1.000) or with a very restricted distribution;

E. Quantitative analyses showing a probability of extinction of 50% (20%, 10%), in the next 100 years.

This system, designed to be applied at a global level for all taxa, remains very general. The related historical data for each species, indeed, are not considered and this can result, in certain cases, in an under- or over-estimation of the threat of extinction.

	Human intervention for the protection of the species recorded in Red Lists often has successful results (measurable mainly at a local level). In Switzerland, for example, some species such as Salvia pratensis (photo 1 - © Flora.cyberia), Pulsatilla vulgaris (photo 2 - © Missouri Botanical Garden) et Polygonatum odoratum (photo 3 - © Frank Rutschmann), ),which were rare in the past, today show a stabilization of their populations.

If we accept that species disappearence is a natural phenomenon, we are forced to notice that the rate of extinction has accelerated alarmingly over the past ten years, and the length of the list of threatened species points inevitably to a “disastrous” situation concerning biodiversity conservation at global level.

Within this context, the recent concept of Blue Lists, developed between 1994 and 1998 by Andreas Gigon et al., becomes relevant. Blue Lists approach the question from another side, by focusing on species from the Red Lists that show a continuous stabilization or increase in abundance, at least at a local level, thanks to certain measures of nature protection. Blue Lists are the indicators of the success of environmental policies.

The Blue List concept has to be further developed with the hope that it will be used by scientific institutions and governments. The consultation of Red and Blue Lists should allow us to obtain a more balanced view of the biodiversity situation at a regional, national and global level, and avoid any hint of resignation.