Disturbance often increases local-scale (α) diversity by suppressing dominant competitors. However, widespread disturbances may also reduce biotic heterogeneity (β diversity) by making the identities and abundances of species more similar among patches. Landscape-scale (γ) diversity may also decline if disturbance-sensitive species are lost. California's vernal pool plant communities are species rich, in part because of two scales of β diversity: (1) within pools, as species composition changes with depth (referred to here as vertical β diversity), and (2) between pools, in response to dispersal limitation and variation in pool attributes (referred to here as horizontal β diversity). We asked how grazing by livestock, a common management practice, affects vernal pool plant diversity at multiple hierarchical spatial scales. In terms of abundance-weighted diversity, grazing increased α both within local pool habitat zones and at the whole-pool scale, as well as γ at the pasture scale without influencing horizontal or vertical β diversity. In terms of species richness, increases in α diversity within habitat zones and within whole pools led to small decreases in horizontal β diversity as species occupancy increased. This had a dampened effect on species richness at the γ (pasture) scale without any loss of disturbance-sensitive species. We conclude that grazing increases species richness and evenness (α) by reducing competitive dominance, without large disruptions to the critical spatial heterogeneity (β) that generates high landscape-level diversity (γ).
Urbanization and anthropogenic development have fundamentally altered ecosystem dynamics on a global scale. Conservation and management of comparatively less modified landscapes adjacent to highly modified landscapes requires careful consideration of interactions between landscape types. Restoration or conservation of habitat within a developed matrix is generally thought to have beneficial effects on landscape-level ecological processes. We propose an ecological spillover framework to critically assess how restoring or conserving species populations within anthropogenically modified landscapes may affect adjacent wildland populations. Within the framework, the spillover process is divided into seven interconnected 'nodes', which identify points at which potential cause-effect relationships may exist between urban and wildland populations. The framework is useful for a wide range of project-specific ecological relationships, and can help scientists and managers identify knowledge gaps and weigh risk in conservation decision-making. We queried the conservation literature to identify research focused on the impacts of urban species populations on regional wildland populations. Our search revealed seven ecological processes that have the potential to be affected by urban to wildland spillover and we found relatively few studies that explicitly analyze spillover effects from urban to wildland areas. Organisms living in urban areas within restored or remnant habitats located in an urban matrix, or within the built environment have largely unknown effects on landscape-level ecological processes. We conclude with a discussion on the critical gaps in research linking these habitats to larger landscape-level ecological understanding, and provide recommendations for research priorities that might illuminate this important aspect of 21st century conservation planning.
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Disque Denúncia, Rio's crime hotline, is located on the third floor of a 1943 art déco building atop the city's main train station. The station sits about midway along Presidente Vargas Avenue, an eight-lane avenue built by a dictator in the forties to parade his tanks and soldiers. Parked at the entrance of the hotline building is a blue-and-white VW Bug marked with the Military Police insignia. When I first came to Brazil, in the 1980s, this is what cops drove. Many of these cars sputtered along on the first round of the country's sugar cane alcohol fuel program, not yet perfected. Between that and the Bug's sluggish pickup, criminals enjoyed a certain advantage. On a fall afternoon,I rode an elevator -manned by an actual operator -to the third floor of the building atop the train station, to visit the founder-director of Disque Denúncia, which means "Dial an Accusation". Zeca Borges is a bearded 72-year-old who likes to wear Panama hats. He and a colleague received me in a conference room, where they showed me a PowerPoint presentation heavy on impact, and then took me on a tour.In an open space housing staff in charge of areas such as social media, press relations, cash rewards and the "Wanted" program, Borges stopped to tell me about drug traffickers' birthdays.In Rio, everybody knows that drug traffickers, intent on keeping good relations with the favela residents who live in their territories, hold enormous birthday barbecues, with abundant and free grilled meat and beer. Having lived here for 34 years,
Landscape architects and ecologists alike are embracing the opportunities urban areas present for restoring biodiversity. Despite sharing this goal, their efforts are rarely coordinated. For landscape architects, aesthetics and programming are at the forefront of design and must be given substantial attention, while ecologists look to scientific research to guide their decision-making. However, the lack of scientific research aimed at developing best ecological practices for native landscaping—particularly at small urban scales—make this difficult at a time when many residents are converting their lawns to more sustainable landscapes (“lawn conversions”). We survey literature from the fields of design and ecology to synthesize relevant information about small-scale urban landscaping projects and to identify instances in which practitioners from both fields are already “speaking the same language,” only with slightly different vocabulary. To further promote transdisciplinary collaborations, we present a new glossary tool to highlight these parallel concepts across fields. We discuss specific situations in which design priorities can be aligned with ecological function and propose that more attention should be placed on traditional principles of garden design, including perception, complexity and repetition, rhythm and order, proportion and scale, and form and structure. Finally, we argue that each new urban lawn conversion presents an opportunity to test ecological theory at the site-scale, conduct much-needed research on the impacts of design principles on habitat potential, and promote a collaborative urban ecological design aesthetic.
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