The relationship between ownership fragmentation and landscape structure in Bastrop County, Texas

Abstract

Few formalized studies have documented the relationships between land ownership fragmentation and landscape structure. The increasing demand for rural land, especially near urban areas, is causing ownership fragmentation. Several parts of Texas are experiencing fragmentation of large rural ownerships, and many assume that landscape and ownership fragmentation are positively correlated. I evaluated the relationships between land ownership fragmentation and landscape structure in an area of rapidly changing ownerships in Central Texas (Bastrop County). Using grid overlays at multiple spatial extents, I correlated ownership size distributions in 1997 to landscape structure in 1999. For each grid cell I calculated land ownership size variables from a land parcel map and landscape metrics (McGarigal and Marks 1994) from a classified Landsat TM (Thematic Mapper) image. In general, landscapes with smaller ownerships tended to have a more heterogeneous or fragmented landscape, and landscapes with larger ownerships tended to have a more homogenous landscape. These relationships remained consistent over multiple spatial extents. I also detected similar relationships from an earlier time period (1981/1984 ownership data/landscape data). Temporal changes indicated that increased ownership fragmentation was correlated with increased shrub/brushland patch density and increased grassland-cropland edge and was slightly correlated with increased conversion of shrub/brushland to grassland-cropland. In this region, land-use changes associated with increased ownership fragmentation may have led to land clearing and fragmentation of shrub/brushland patches. No relationships were detected between ownership fragmentation and pine-oak forestland fragmentation of the "Lost Pines" region. This might be due to several large ownerships being maintained, and the trees' aesthetic value causing landowners to keep their property forested.