Urbanization has many effects on natural environments. These include fragmentation of habitats into remnants, provision of new and artificial habitats, introduction of feral species, increased pollution of land, air and water and ongoing physical disturbances of large numbers of people interacting with their surroundings. Effects of urbanization have been considered far more widely in terrestrial than in marine habitats, even though many large cities are on the coast or in estuaries and therefore impact adjacent waters. In addition, the relative importance that ecologists place on different classesof impacts appears to reflect their background in terrestrial or aquatic ecology. Much research of urbanization in terrestrial habitats has considered isolation and connectedness of habitat fragments, addition of new built structures and introduced species. In adjacent marine waters, most research considers problems of water quality or pollution. This division of interest and emphasis, with little overlap, interaction or quantitative comparison between the two approaches, decreases our understanding of the overall ecological effects of urbanization. Here, I review selected publications in urban ecology in marine and terrestrial habitats to quantify differences in interest, methodology and analyses, to attempt to develop a more holistic approach to the ecology of urbanization.
