Table 1. Observed, calculated, and predicted transition rates through Red List categories (in percentage of species per decade). Positive values indicate net deterioration (i.e., more species moving into higher threat categories than lower threat categories), whereas negative values indicate net improvement. Upper rows simplified from Brooke et al. (2008). Bottom row based on revised criterion E values suggested in the text.
| |
| |
| |
|
Threat category |
| |
|
|
| |
|
Least Concern |
Near Threatened |
Vulnerable |
Endangered |
Critically Endangered
|
| |
| All bird species
1988-2004 |
Observed |
0.63 |
3.74 |
4.54 |
4.09 |
-2.39 |
| Observed adjusted to exclude the
impact of conservation action |
0.63 |
3.82 |
5.08 |
4.89 |
3.98 |
| |
|
|
|
|
|
|
| Critically Endangered
species
1994-2004 |
Observed |
– |
– |
– |
– |
1.70 |
| Observed adjusted to exclude the
impact of conservation action |
– |
– |
– |
– |
10.8 |
| |
|
|
|
|
|
|
| |
Predicted using current criterion
E |
– |
– |
8.30 |
40.0 |
50.0 |
| |
Predicted using suggested revision
of criterion E |
– |
– |
4.24 |
15.7 |
25.0 |
|
| |
|