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Urban forest naturalization has gained momentum within municipal planning and non-governmental organizations. As the interest in naturalization increases, so does the impetus for exploring its conceptual and practical dimensions. Naturalization is a form of ecological restoration with prominent social dimensions. One motivation is reintegrating the urban forest to a greater extent into its surroundings, increasing the habitat available for native species. However, naturalization is not always desirable, as we may want to use and modify certain areas for cultural purposes, or feasible, as some species may be unable to establish in an urban setting. This paper examines the concepts underlying naturalization and how they influence naturalization decisions and goals. It then provides a framework for urban forest naturalness and explores potential applications of naturalness assessments in urban forest management. The framework outlines 37 different biotic and abiotic dimensions of naturalness that can help urban forest decision-makers visualize and manage the urban forest through understanding its individual parts and thus the whole. If a site is weak in particular dimensions, actions can be directed to increase the naturalness of these components. Similarly, some dimensions may be of more interest than others, such as increasing habitat suitability for a particular species. We then offer real and hypothetical examples of applying the framework to urban forest management. The benefits of a naturalized urban forest are many. It provides habitat for native species and has an important role as a biological teaching tool for urban residents. In developing this framework, we hope to expand the discussion on naturalization beyond simply planting native species and ceasing mowing to positioning urban forests in a broader landscape. [ABSTRACT FROM AUTHOR]

Aquatic resource managers are continually faced with construction or site development proposals which, if allowed to proceed, would ultimately alter the physical structure and cover of fish habitat. In the absence of clear quantitative guidelines linking the change in habitat to fish, resource managers often use the change in habitat area as a basis for decisions. To assess the weight of scientific evidence in support of management decisions, we summarized both the observational and experimental freshwater fish-habitat literature. We then extracted data from experimental studies (where possible) for inclusion in a meta-analysis, to provide a more rigorous assessment of the published results of experimental habitat manipulations. We found relatively strong and consistent correlational evidence linking fish and physical habitat features, yet inconsistent evidence when narratively reviewing the experimental literature. On the whole, decreases in structural habitat complexity are detrimental to fish diversity and can change species composition. Increases in structural complexity showed increases, decreases, or no measurable changes in species and (or) communities. The majority of our meta-analyses resulted in supporting a direct link between habitat and fish abundance or biomass, with fish biomass responding most strongly to habitat change. Habitat alterations are most likely to affect individual species or community structure, and thus evaluating the extent of the effect on a biological basis depends on management objectives. [ABSTRACT FROM AUTHOR]