Ecological Applications, 17(7), 2007, pp. 2011–2023 Ó 2007 by the Ecological Society of America PATTERNS OF HOUSES AND HABITAT LOSS FROM 1937 TO 1999 IN NORTHERN WISCONSIN, USA CHARLOTTE E. GONZALEZ-ABRAHAM, 1 VOLKER C. RADELOFF, 1,5 TODD J. HAWBAKER, 1 ROGER B. HAMMER, 2 SUSAN I. STEWART, 3 AND MURRAY K. CLAYTON 4 1 Department of Forest Ecology and Management, University of Wisconsin–Madison, Madison, Wisconsin 53706 USA 2 Department of Sociology, Oregon State University, Corvallis, Oregon 97331 USA 3 U.S. Forest Service Northern Research Station, Evanston, Illinois 60201 USA 4 Department of Statistics, University of Wisconsin–Madison, Madison, Wisconsin 53706 USA Abstract. Rural America is witnessing widespread housing development, which is to the detriment of the environment. It has been suggested to cluster houses so that their disturbance zones overlap and thus cause less habitat loss than is the case for dispersed development. Clustering houses makes intuitive sense, but few empirical studies have quantified the spatial pattern of houses in real landscapes, assessed changes in their patterns over time, and quantified the resulting habitat loss. We addressed three basic questions: (1) What are the spatial patterns of houses and how do they change over time; (2) How much habitat is lost due to houses, and how is this affected by spatial pattern of houses; and (3) What type of habitat is most affected by housing development. We mapped 27 419 houses from aerial photos for five time periods in 17 townships in northern Wisconsin and calculated the terrestrial land area remaining after buffering each house using 100- and 500-m disturbance zones. The number of houses increased by 353% between 1937 and 1999. Ripley’s K test showed that houses were significantly clustered at all time periods and at all scales. Due to the clustering, the rate at which habitat was lost (176% and 55% for 100- and 500-m buffers, respectively) was substantially lower than housing growth rates, and most land area was undisturbed (95% and 61% for 100-m and 500-m buffers, respectively). Houses were strongly clustered within 100 m of lakes. Habitat loss was lowest in wetlands but reached up to 60% in deciduous forests. Our results are encouraging in that clustered development is common in northern Wisconsin, and habitat loss is thus limited. However, the concentration of development along lakeshores causes concern, because these may be critical habitats for many species. Conservation goals can only be met if policies promote clustered development and simultaneously steer development away from sensitive ecosystems. Key words: clustered development; disturbance zone; exurban; habitat loss; housing growth; rural sprawl. INTRODUCTION The United States is experiencing strong housing growth both in suburban and rural areas (Fuguitt et al. 1998, Hobbs and Stoops 2002). In the 1990s alone, 13 million new housing units were built in the United States, many of which were placed in areas with high natural amenities (McGranahan 1999). The trend toward strong housing growth in rural areas started in the late 1960s (Radeloff et al. 2005), and the 1970s was the first decade when non-metropolitan population growth rates exceeded those of metropolitan areas (Fuguitt 1985), and reoccurred in the 1990s (Beale and Fuguitt 1990, Long and Nucci 1997). Strong rural housing growth raises the question how rural sprawl is affecting the environment, and what management recommendations can be given to mitigate these effects. Environmental effects begin during the construction phase of a house, when natural vegetation is disturbed or removed, soil erosion is common (Brown 2003), and habitat is lost and fragmented (Theobald et al. 1997). After the construction, exotic species are introduced through gardening and landscaping (Suarez et al. 1998), and wildlife movement is restricted due to roads and fences (Friesen et al. 1995, Hostetler 1999). Accordingly, areas with higher housing density exhibit fewer neo- tropical migrant birds (Kluza et al. 2000, Pidgeon et al. 2007), lower densities of ground and shrub nesters (Maestas et al. 2003), higher nest abandonment (Kluza et al. 2000, Miller and Hobbs 2000), and larger populations of species that thrive in human-dominated environments, including non native species (Hoffman and Gottschang 1977, Coleman and Temple 1993). Nest predation by pets is higher near houses (Coleman and Temple 1993, Odell and Knight 2001), and avoidance behavior is common in species not adapted to human presence (Holmes et al. 1993, Rodgers and Smith 1995). The multitude of environmental effects caused by houses Manuscript received 27 November 2006; revised 2 March 2007; accepted 29 March 2007. Corresponding Editor: T. R. Simons. 5 Corresponding author. E-mail: radeloff@wisc.edu 2011