Top journals in ecology and environmental sciences

	Journal	Papers	Citations	Citations per paper
1	Annual Review of Ecology, Evolution & Systematics	131	15,293	116.74
2	Nature	395	41,042	103.90
3	Science	397	34,568	87.07
4	Trends in Ecology and Evolution	7	39,356	54.13
5	Ecological Monographs	309	11,310	36.60
6	Proceedings of the National Academy of Sciences of the USA	491	17,088	34.80
7	Systematic Biology	416	12,194	29.31
8	Ecology	3,161	80,313	25.41
9	Ecology Letters	1,133	26,3	23.24
10	The American Naturalist	1,618	36,694	22.68
11	Conservation Biology	1,729	36,209	20.94
12	Environmental Health Perspectives	3,374	70,023	20.75
13	Molecular Ecology	3,345	69,5	20.71
14	Ecological Applications	1,711	34,899	20.40
15	Journal of Ecology	1,081	20,969	19.40
16	Global Change Biology	1,508	,995	18.56
17	Journal of Applied Ecology	1,162	21,032	18.10
18	Oecologia	3,219	56,010	17.40
19	Ecosystems	705	12,199	17.30
20	Environmental Science & Technology	10,006	171,816	17.17

Based on citations per paper among journals with 10,000 or more citations. The data above were extracted from Thomson Reuters’ Essential Science Indicators database. This database, currently covering the period January 1998 to October 2008, surveys only journal articles (original research reports and review articles) indexed by Thomson Reuters. Articles are assigned to a category based on the journals in which they were published and Thomson Reuters’ journal-to-category field-definition scheme. Both articles tabulated and citation counts for those articles are for the period indicated. Here, our ranking of journals in ecology and environmental sciences is made by citations per paper to reveal the weighted impact. Essential Science Indicators lists journals ranked in the top 50 per cent for a field over a given period, based on total citations. In ecology and environmental sciences, 168 journals are listed, meaning 336 journals in the field were surveyed. Of these 168 journals, 54 received 10,000 or more citations during the period. This ranking should be recognised as distinctly different from Thomson Reuters’ impact-factor rankings, which are presented in the Journal Citation Reports issued each year. The impact factor is calculated as citations in year three to a journal’s contents in years one and two, divided by the number of so-called citable items (regular articles and reviews) in years one and two. Thus, the above ranking reveals longer-term impact (citations per paper). The data for the multidisciplinary journals listed – Science, Nature and the Proceedings of the National Academy of Sciences of the USA – take into account only those articles that have been classified by Thomson Reuters as ecology and environmental sciences papers. For more information on Thomson Reuters’ Essential Science Indicators, see http://scientific.thomsonreuters.com/products/esi.