Elizabeth M. Cook

Residential landscapes as social-ecological systems: a synthesis of multi-scalar interactions between people and their home environment

Residential landscapes are a common setting of human-environment interactions. These ubiquitous ecosystems provide social and ecological services, and yard maintenance leads to intended and unintended ecological outcomes. The ecological characteristics of residential landscapes and the human drivers of landscape management have been the focus of disciplinary studies, often at a single scale of analysis. However, an interdisciplinary examination of residential landscapes is needed to understand the feedbacks and tradeoffs of these complex adaptive social-ecological systems as a whole. Our aim is to synthesize the diversity of perspectives, scales of analysis, and findings from the literature in order to 1) contribute to an interdisciplinary understanding of residential landscapes and 2) identify research needs while providing a robust conceptual approach for future studies. We synthesize 256 studies from the literature and develop an interdisciplinary, multi-scalar framework on residential landscape dynamics. Complex human drivers (attitudinal, structural, and institutional factors) at multiple scales influence management practices and the feedbacks with biophysical characteristics of residential landscapes. However, gaps exist in our interdisciplinary understanding of residential landscapes within four key but understudied areas: 1) the link between social drivers and ecological outcomes of management decisions, 2) the ecosystem services provided by these landscapes to residents, 3) the interactions of social drivers and ecological characteristics across scales, and 4) generalizations of patterns and processes across cities. Our systems perspective will help to guide future interdisciplinary collaborations to integrate theories and research methods across geographic locations and spatial scales.

Communicating with the public: opportunities and rewards for individual ecologists

Many ecologists are interested in communicating science to the public and addressing societal concerns about environmental issues. Individual ecologists need to consider whether, when, and how this should be done. We propose that public outreach activities can be beneficial for ecologists at all stages of their career. There are diverse opportunities for such involvement, and these can vary enormously in terms of time and expertise required. Trends within the science of ecology, especially research focused on social-ecological systems, are likely to promote increased interactions with stakeholders and policy makers. To be effective in these interactions, ecologists should consider new approaches to communication and be aware of the potential roles scientists can play in public policy debates. Professional ecologists need to engage with non-scientific audiences; a review of such activities should be included in considerations for promotion, recognition, and awards, while also acknowledging variations in the inclinations and abilities of individual scientists. There are, however, few current standards for how much time ecologists should commit to public outreach, how time allocation might change over a career, or how to evaluate the quality of such activities. We ask ecologists to consider ways to evaluate the quality of interactions with the public and how to reward these efforts appropriately.

Phosphorus in Phoenix: a budget and spatial representation of phosphorus in an urban ecosystem

As urban environments dominate the landscape, we need to examine how limiting nutrients such as phosphorus (P) cycle in these novel ecosystems. Sustainable management of P resources is necessary to ensure global food security and to minimize freshwater pollution. We used a spatially explicit budget to quantify the pools and fluxes of P in the Greater Phoenix Area in Arizona, USA, using the boundaries of the Central Arizona-Phoenix Long-Term Ecological Research site. Inputs were dominated by direct imports of food and fertilizer for local agriculture, while most outputs were small, including water, crops, and material destined for recycling. Internally, fluxes were dominated by transfers of food and feed from local agriculture and the recycling of human and animal excretion. Spatial correction of P dynamics across the city showed that human density and associated infrastructure, especially asphalt, dominated the distribution of P pools across the landscape. Phosphorus fluxes were dominated by agricultural production, with agricultural soils accumulating P. Human features (infrastructure, technology, and waste management decisions) and biophysical characteristics (soil properties, water fluxes, and storage) mediated P dynamics in Phoenix. P cycling was most notably affected by water management practices that conserve and recycle water, preventing the loss of waterborne P from the ecosystem. P is not intentionally managed, and as a result, changes in land use and demographics, particularly increased urbanization and declining agriculture, may lead to increased losses of P from this system. We suggest that city managers should minimize cross-boundary fluxes of P to the city. Reduced P fluxes may be accomplished through more efficient recycling of waste, therefore decreasing dependence on external nonrenewable P resources and minimizing aquatic pollution. Our spatial approach and consideration of both pools and fluxes across a heterogeneous urban ecosystem increases the utility of nutrient budgets for city managers. Our budget explicitly links processes that affect P cycling across space with the management of other resources (e.g., water). A holistic management strategy that deliberately couples the management of P and other resources should be a priority for cities in achieving urban sustainability.

Meta-studies in land use science: Current coverage and prospects

Land use science has traditionally used case-study approaches for in-depth investigation of land use change processes and impacts. Meta-studies synthesize findings across case-study evidence to identify general patterns. In this paper, we provide a review of meta-studies in land use science. Various meta-studies have been conducted, which synthesize deforestation and agricultural land use change processes, while other important changes, such as urbanization, wetland conversion, and grassland dynamics have hardly been addressed. Meta-studies of land use change impacts focus mostly on biodiversity and biogeochemical cycles, while meta-studies of socioeconomic consequences are rare. Land use change processes and land use change impacts are generally addressed in isolation, while only few studies considered trajectories of drivers through changes to their impacts and their potential feedbacks. We provide a conceptual framework for linking meta-studies of land use change processes and impacts for the analysis of coupled human–environmental systems. Moreover, we provide suggestions for combining meta-studies of different land use change processes to develop a more integrated theory of land use change, and for combining meta-studies of land use change impacts to identify tradeoffs between different impacts. Land use science can benefit from an improved conceptualization of land use change processes and their impacts, and from new methods that combine meta-study findings to advance our understanding of human–environmental systems.

A comparative gradient approach as a tool for understanding and managing urban ecosystems

To meet the grand challenges of the urban century—such as climate change, biodiversity loss, and persistent poverty—urban and ecological theory must contribute to integrated frameworks that treat social and ecological dynamics as interdependent. A socio-ecological framework that encapsulates theory from the social and ecological sciences will improve understanding of metropolitan dynamics and generate science for improved, sustainable management of urban ecosystems. To date, most urban ecological research has focused on single cities. A comparative approach that uses gradients within and between cities is a useful tool for building urban ecological theory. We offer five hypotheses that are testable using a comparative, gradient approach: (i) the current size, configuration, and function of larger metropolitan ecosystems predicts the potential trajectory of smaller urban areas; (ii) timing of growth explains the greatest variance in urban ecosystem structure and function; (iii) form and function of urban ecosystems are converging over time; (iv) urban ecosystems become more segregated and fragmented as populations increase; and (v) larger cities are more innovative than smaller cities in managing urban ecosystems.

Urban–Suburban Biodiversity

For the first time in history, more people live in cities than in nonurban areas. Thus for most people, the urban ecosystem is the place for daily interactions with the environment. Scientists study urban ecological systems for two reasons: (1) they provide a set of services to urban residents; and (2) they can be used as a testing ground for ecological theory. This article reviews the major impacts people have on urban biodiversity at household, neighborhood, city, and global scales.

Mixed method approach to assess atmospheric nitrogen deposition in arid and semi-arid ecosystems

Arid and semi-arid ecosystems (aridlands) cover a third of Earths terrestrial surface and contain organisms that are sensitive to low level atmospheric pollutants. Atmospheric nitrogen (N) inputs to aridlands are likely to cause changes in plant community composition, fire frequency, and carbon cycling and storage. However, few studies have documented long-term rates of atmospheric N inputs in aridlands because dry deposition is technically difficult to quantify, and extensive sampling is needed to capture fluxes with spatially and temporally heterogeneous rainfall patterns. Here, we quantified long-term spatial and temporal patterns of inorganic N deposition in protected aridland ecosystems across an extensive urban-rural gradient using multiple sampling methods. We compared long-term rates of N deposition from ion-exchange resin (IER) collectors (bulk and throughfall, 2006-2015), wet-dry bucket collectors (2006-2015), and dry deposition from the inferential method using passive samplers (2010-2012). From mixed approaches with IER collectors and inferential methods, we determined that 7.2 ± 0.4 kgNha-1y-1 is deposited to protected Sonoran Desert within metropolitan Phoenix, Arizona and 6.1 ± 0.3 kgNha-1y-1 in nearby desert ecosystems. Regional scale models overestimated deposition rates for our sampling period by 60% and misidentified hot spots of deposition across the airshed. By contrast, the easy-deployment IER throughfall collectors showed minimal spatial variation across the urban-rural gradient and underestimated deposition fluxes by 54%, largely because of underestimated dry deposition in throughfall. However, seasonal sampling of the IER collectors over 10 years allowed us to capture significant seasonal variation in N deposition and the importance of precipitation timing. These results, derived from the longest, spatially and temporally explicit dataset in drylands, highlight the need for long-term, mixed methods to estimate atmospheric nutrient enrichment to aridlands in a rapidly changing world.