Table 1.

Progress toward Nature Needs Half by biome, showing the number of ecoregions in each category, based on habitat protected and habitat remaining.

Biome name and number	Percentage of Earth's terrestrial area	Mean percentage of protected within biome	(1) Half Protected	(2) Nature Could Reach Half	(3) Nature Could Recover	(4) Nature Imperiled	Total
Forested biomes
1. Tropical and subtropical moist broadleaf forests	14.4	12	24	116	46	44	230
2. Tropical and subtropical dry broadleaf forests	2.9	8	2	8	20	26	56
3. Tropical and subtropical coniferous forests	0.5	12	1	6	7	1	15
4. Temperate broadleaf and mixed forests	9.3	10	7	21	30	25	83
5. Temperate conifer forests	2.8	17	2	16	19	10	47
6. Boreal forests or taiga	11.4	9	1	23	2	0	26
14. Mangroves	0.2	26	3	8	6	2	19
Forested biome subtotal	41.5	13	40	198	130	108	476
Nonforested biomes
7. Tropical and subtropical grasslands, savannas, and shrublands	15.8	15	5	14	18	20	57
8. Temperate grasslands, savannas, and shrublands	7.8	4	0	11	13	24	48
9. Flooded Grasslands and Savannas	0.9	32	8	4	9	4	25
10. Montane grasslands and shrublands	3.6	25	9	11	14	12	46
11. Tundra	8.7	8	26	24	0	1	51
12. Mediterranean forests, woodlands, and scrub	2.4	18	2	5	25	8	40
13. Deserts and xeric shrublands	19.3	6	8	46	19	30	103
Nonforested biome subtotal	58.5	10	58	115	98	99	370
Total	100	12	98	313	228	207	846

Note: The ecoregion data can be found in supplemental tables S1 and S2. (1) Half Protected: 50% or more of the total ecoregion area is protected. (2) Nature Could Reach Half: Less than 50% of the total ecoregion area is protected, but the sum of the total ecoregion protected and unprotected natural habitat remaining is 50% or more. (3) Nature Could Recover: The sum of the amount of natural habitat remaining and the amount of the ecoregion that is protected is less than 50% but more than 20%. (4) Nature Imperiled: The sum of the amount of natural habitat remaining and the amount of the ecoregion that is protected is less than or equal to 20%.