Draft:Kurt Riitters

Riitters worked for Crown Zellerbach (1983–1985) while completing his dissertation,^[5] then as a contractor at several Environmental Protection Agency (EPA) facilities (1985–1993).^[5][6] His civil service included the Tennessee Valley Authority (1993–1997),^[7] the U.S. Geological Survey (1997–2000),^[8] and the U.S. Forest Service (2000–2025).^[9][10][2] He held a concurrent appointment as an adjunct professor at North Carolina State University's Department of Forestry and Environmental Resources (1999–2023).^[11][12]

He served as president of the United States Regional Association of the International Association for Landscape Ecology (US-IALE) from 2012 to 2014.^[13] In 2019 he received the Distinguished Landscape Ecologist Award from US-IALE,^[a] which the organization describes as its most prestigious honor.^[15][16][1] He retired from the Forest Service in 2025.^[2]

Riitters authored more than 100 peer-reviewed papers.^[17][2] His research primarily used land cover data derived from satellite imagery to study landscape patterns at regional to global scales, addressing the questions of which patterns occur where, at what measurement scales, and how they change over time.^[18][19]

In a 1995 study, Riitters used factor analysis to reduce the many pattern metrics then in use to a small set of fundamental components.^[20][21] The paper was identified among the "groundbreaking or exceptionally influential events in the development of landscape ecology"^[22] and was the second most-cited paper published in the journal Landscape Ecology during its first 30 years.^[23]

Riitters' subsequent research used the "moving window" approach, which calculates a pattern metric for each location from the contents of a window surrounding it.^[21][18] In contrast to standard practice at the time, it treats patterns as contextual attributes that vary continuously across geographic space and measurement scale (window size),^[19] offering new perspectives on spatial variation across regions.^[24] This is illustrated at right in animated maps depicting the "landscape mosaic" — a window metric of land use composition — in eastern North America from 1992 to 2015; the expanding saturation of blue and red colors indicates, respectively, increasing presence of agriculture (A) and developed (D) land use in otherwise "natural" (N) windows.^[25][26]

Riitters led the first multi-scale global assessment of forest fragmentation in 2000.^[27][28] In a higher-resolution 2002 study of the contiguous U.S.,^[29] he found that forest fragmentation was so pervasive that edge effects potentially affected most forested land; the study also introduced a multi-scale framework for interpreting the "forest area density" metric that was later adopted for national reporting of forest fragmentation.^[b][30][31] In 2016, he used global tree cover maps with roughly 1,100 times finer spatial resolution than the 2000 study, finding that the global area of "interior forest"^[c] declined by approximately 10% (3.8 million km²) between 2000 and 2012 — a rate more than three times that of overall forest area loss; interior forest was lost in temperate forests at rates approximating those in the tropics.^[32][33][34]

Riitters' collaboration with scientists at the European Commission's Joint Research Centre applied mathematical morphology to landscape pattern mapping.^[35][36][37] He led a 2007 study of random (neutral) forest/nonforest maps which discovered a new type of phase change — an abrupt shift from interior to exterior forest edge — that occurred at a much higher critical threshold than the classic phase change involving a map-spanning cluster.^[d][38][39] He also helped to develop the related software tools GuidosToolbox^[40] and GuidosToolbox Workbench,^[41] both of which also included the moving window algorithms. GuidosToolbox Workbench was deployed on the FAO's SEPAL^[42] cloud platform for global forest monitoring.^[43]

Riitters produced two maps of landscape patterns for the National Atlas of the United States.^[44][45] He introduced the assessment of landscape patterns into the RPA Assessment, mandated under the Forest and Rangeland Renewable Resources Planning Act of 1974, and into the National Report on Sustainable Forests, the U.S. submission under the international Montréal Process.^[46][31] The forest area density metric used in these assessments was also adopted by the EPA's Report on the Environment^[47] and the H. John Heinz III Center's State of the Nation's Ecosystems reports.^[48][49] For their 2008 report, the Heinz Center also used a version of the landscape mosaic metric to define the "pattern of 'natural' landscapes", the report's core national indicator of landscape pattern.^[50]

His moving window method was used to produce global maps of the proximate causes of forest fragmentation for the Millennium Ecosystem Assessment.^[51][52] The forest area density metric was adopted internationally in the State of Europe's Forests 2020 report published by the Ministerial Conference on the Protection of Forests in Europe^[53] and the FAO 2020 Global Forest Resources Assessment.^[54] It also serves as a biodiversity indicator under the European Union's Nature Restoration Law^[e][55] and a headline indicator tracked by the European Environment Agency.^[56]

• Riitters, K.H., R.V. O'Neill, C.T. Hunsaker, J.D. Wickham, D.H. Yankee, S.P. Timmins, K.B. Jones, and B.L. Jackson. 1995. A factor analysis of landscape pattern and structure metrics. Landscape Ecology 10(1):23–39. doi:10.1007/BF00158551
• Riitters, Kurt, James Wickham, Robert O'Neill, Bruce Jones, and Elizabeth Smith. 2000. Global-scale patterns of forest fragmentation. Conservation Ecology 4(2):3.
• Riitters, Kurt H., James D. Wickham, Robert V. O'Neill, K. Bruce Jones, Elizabeth R. Smith, John W. Coulston, Timothy G. Wade, and Jonathan H. Smith. 2002. Fragmentation of Continental United States Forests. Ecosystems 5(8):815–822. doi:10.1007/s10021-002-0209-2
• Riitters, Kurt H., and James D. Wickham. 2003. How far to the nearest road? Frontiers in Ecology and the Environment 1(3):125–129. doi:10.1890/1540-9295(2003)001[0125:HFTTNR]2.0.CO;2
• Riitters, Kurt, James Wickham, Jennifer K. Costanza, and Peter Vogt. 2016. A global evaluation of forest interior area dynamics using tree cover data from 2000 to 2012. Landscape Ecology 31(1):137–148. doi:10.1007/s10980-015-0270-9
• Riitters, Kurt, Karen Schleeweis, and Jennifer Costanza. 2020. Forest Area Change in the Shifting Landscape Mosaic of the Continental United States from 2001 to 2016. Land 9(11):417. doi:10.3390/land9110417