| High productivity and accessibility to humans have made coastal wetlands attractive sites for human settlements. This study analyzed the wetland landscape patterns in Galveston Bay, Texas. There were two objectives in this study. First, the study described the relationships between the fractal dimension and factors which affect the wetland landscapes: land use, vegetation type, size, location, and level of human disturbance. Second, a historical database was constructed to contrast wetland areas which had experienced different levels of disturbance between 1956 and 1989. The perimeter-area method was used to calculate the fractal dimension. There was a significant difference in the fractal dimension of wetlands when classified according to land use, vegetation type, size, and level of human disturbance. Furthermore, increasing the size of the road buffers did not have a significant effect on the fractal dimension of wetlands. The historical databases depicted the effects of three different disturbance regimes on wetland landscape composition and configuration. A number of indices, such as fractal dimension, dominance, and diversity, were used to characterize spatial heterogeneity in the historical database. Lake Stephenson, an area of low disturbance, experienced no changes in wetland composition and abundance over time. Anahuac, an area of medium disturbance, experienced changes in both wetland composition and abundance. Texas City, an area of high disturbance, experienced a change in wetland composition. These differences can be associated to the type and level of disturbance present; however, more evidence is needed to determine whether certain landscape patterns have a cohesive structure which persists in the face of disturbance. These results will be important in determining how wetlands can be managed as natural resources and nature reserves. |
