Urban Agroecology

Interdisciplinary Research and Future Directions

Monika Egerer, Hamutahl Cohen, Monika Egerer, Hamutahl Cohen

• Publisher: CRC Press
• Year: 2020
• ISBN:
  9781000259506
• Edition: 1
• Topic: Ciencias biológicas
• Subtopic: Calentamiento global y cambio climático

Today, 20 percent of the global food supply relies on urban agriculture: social-ecological systems shaped by both human and non-human interactions. This book shows how urban agroecologists measure flora and fauna that underpin the ecological dynamics of these systems, and how people manage and benefit from these systems. It explains how the sociopolitical landscape in which these systems are embedded can in turn shape the social, ecological, political, and economic dynamics within them. Synthesizing interdisciplinary approaches in urban agroecology in the natural and social sciences, the book explores methodologies and new directions in research that can be adopted by scholars and practitioners alike.

With contributions from researchers utilizing both social and natural science approaches, Urban Agroecology describes the current social-environmental understandings of the science, the movement and the practices in urban agroecology. By investigating the role of agroecology in cities, the book calls for the creation of spaces for food to be sustainably grown in urban spaces: an Urban Agriculture (UA) movement. Essential reading for graduate students, practitioners, policy makers and researchers, this book charts the course for accelerating this movement.

1

An Expanded Scope of Biodiversity in Urban Agriculture, with Implications for Conservation

Sacha K. Heath,¹,^§ Nina S. Fogel,² Jennifer C. Mullikin,² and Trey Hull³

¹ Living Earth Collaborative

² Department of Biology, Saint Louis University

³ Department of Integrated and Applied Sciences, Saint Louis University

^§ Corresponding author: Email- [email protected], Living Earth Collaborative, Washington University, One Brookings Drive, St. Louis, MO 63130, USA

Contents

• 1.1Introduction
• 1.2Methods
  • 1.2.1Systematic Literature Review
  • 1.2.2Data Extraction and Analyses
• 1.3General Findings
• 1.4Biodiversity Accounts
  • 1.4.1Plants
    • 1.4.1.1General Plant Communities
    • 1.4.1.2Native Plants
    • 1.4.1.3Invasive and Non-Native Plants
    • 1.4.1.4Crop Plants
    • 1.4.1.5Medicinal Plants
  • 1.4.2Invertebrates
    • 1.4.2.1Pollinators and Pollination
    • 1.4.2.2Invertebrate Crop Pests and Natural Enemies
    • 1.4.2.3Soil Macrofauna
    • 1.4.2.4Disease Vectors and Hosts
    • 1.4.2.5Additional Invertebrate Biodiversity
  • 1.4.3Birds
  • 1.4.4Mammals
  • 1.4.5Reptiles
  • 1.4.6Amphibians
  • 1.4.7Soil Microbes
  • 1.4.8Fish
• 1.5Consideration of Space and Scale
• 1.6Human Engagement in Biodiversity Conservation through Urban Agriculture
• 1.7Information Gaps and Future Directions
• 1.8Conclusions
• References

Key Words: biodiversity, agriculture, urban, conservation

1.1 Introduction

Urbanization expanded dramatically across the globe during the twentieth century (Angel et al. 2011). While the urban footprint currently constitutes less than 3% of global land area, it is projected to nearly triple in area between 2000 and 2030 (Schneider et al. 2010, United Nations 2015). Compared to other land uses, urbanization has a disproportionate impact on biodiversity because human concentrations tend to spatially coincide with regions of high biodiversity (Luck 2007). At the same time, semi-natural habitats in urban areas (i.e., urban green infrastructure) can function as biodiversity refuges (Lundholm and Richardson 2010, Goddard et al. 2010, Aronson et al. 2017, Hall et al. 2017). Urban agriculture is a major component of urban green infrastructure, which includes private residential gardens, community (in North America) or allotment (in Europe) gardens, green roofs and vertical walls, and urban orchards (Lin and Egerer 2017). Given the space urban agriculture occupies in cities, and agriculture's dependence on beneficial services conferred by animals (i.e., pollination and predation), urban agroecosystems are positioned to play a key role in harboring and potentially sustaining biodiversity in cities (Lin et al. 2015, Lin and Egerer 2017, Artmann and Sartison 2018).

We set out to explore what is known by the scientific community about the role of urban agroecosystems and urban agriculture broadly in biodiversity conservation. We performed a systematic review and explicitly used broadly defined terms in an attempt to capture studies from urban agricultural settings around the world with a diversity of perspectives about what is meant by biodiversity and conservation. Several reviews within the last decade have assessed the current state of knowledge of biodiversity in cultivated urban environments. These efforts have provided much needed and succinct reviews of the topic of biodiversity and urban agriculture by focusing explicitly on residential or community gardens (Goddard et al. 2010, Guitart et al. 2012, Knapp 2014), urban food (versus ornamental) production (Clucas et al. 2018), in specific geographic regions (i.e., the “global north”; Artmann and Sartison 2018), or on specific taxa (e.g., Rodewald 2016). Thus, we aimed to complement, rather than reproduce, the efforts of previous reviews in several ways. First, we extended our definition of urban agriculture to include the production of ornamental and food plants. Second, we expanded our biodiversity-related search terms to include individual taxa, biodiversity and wildlife indices, and agrodiversity—within all global regions. Finally, we sought to expand the pool of studies on individual taxa by reviewing articles that included urban agricultural study sites as one of many site types—including those that did not explicitly study specific aspects of urban agriculture.

1.2 Methods

1.2.1 Systematic Literature Review

We performed a systematic literature review following guidelines and suggestions of Collaboration for Environmental Evidence (2013) and Livoreil et al. (2017). We used the following search terms and Boolean operators:

• (biodiversity OR wildlife OR arthropod* OR invertebrate* OR insect* OR spider* OR bee* OR butterfly* OR pollinator* OR natural enemy* OR beneficial insect* OR pest* OR mammal* OR bat* OR bird* OR amphibian* OR frog* OR salamander* OR reptile* OR lizard* OR snake* OR plant* OR flora OR vegetation OR conservation)

AND

• (urban* OR city OR neighborhood*)

AND

• (agriculture* OR garden* OR farm*)

We searched the Web of Science and Agricola databases within ‘Topics' and ‘Keywords Anywhere’, and within all years available (1900–2019 and 1970–2019, respectively). We searched all years in Google Scholar using the ‘allintitle:’ function and restricted the search to not include citations or patents. As of June 21, 2019, we compiled a total of 9,066 citations from these separate searches; deleting duplicates resulted in 6,688 citations. A single author manually read through titles twice, removing theses, conference abstracts, magazines, and non-refereed and predatory journals (identified as such by Ulrich's Periodicals Directory or the Directory of Open Access Journals), resulting in 1,311 titles. We sorted these titles into loose taxa- and subject- subsections among the four authors who read and retained 968 abstracts. After skimming the full texts, we retained and reported on a final set of articles.

We retained original research articles (i.e., reviews were discarded) only if they comprised all three components—urban, agriculture, and biodiversity—defined as follows:

1. Urban. Human dominated landscapes such as cities, suburbs, or peri-urban areas.
2. Agriculture. Human cultivated plants or animals for food, medicinal, or ornamental purposes.
3. Biodiversity. Any wild living organism. Inclusive in this are individual taxa, indices such as species, functional, or phylogenetic diversity and richness, colloquial terms such as “wildlife” and agro-biodiversity.

While evaluating titles, abstracts, and full papers, we made explicit attempts to reduce western hemisphere and global north biases in our review by seeking out culturally and regionally dependent terms with which we were not initially familiar.

1.2.2 Data Extraction and Analyses

We obtained and categorized data from the final article set in four ways. First, we extracted basic information such as article publication year and journal title from the citation records. Second, we used a Latent Dirichlet Allocation (LDA) topic model to assign articles to four general topic groups based on clusters of words extracted from the abstracts (R package ‘revtools'; Westgate 2019, R Core Team 2019). The LDA performed 20,000 iterations of a Gibbs sampler algorithm to find an optimal set of 4 distinct topical clusters (details of the modeling procedure, data, and code can be accessed in (Appendix 1; Heath et al. 2020). Third, we extracted and categorized more detailed information from the articles manually with a set of eight variables and multiple-choice or choose-all-that-apply options for each (Table 1.1). Finally, we reviewed articles in written accounts, organized by general types of biodiversity.

TABLE 1.1
Multiple choice variables used to manually categorize the final set of articles

Variable	Description
Countries	Countries in which the study took place.
Municipalities	Municipalities in which the study took place.
Biodiversity type	General types of biodiversity studied.
Urban type	The type of urban region in which the study took place (choose all that apply^a): urban; peri-urban; suburban; exurban; other
Agriculture type	The type of agriculture (choose all that apply): community/allotment garden or farm; residential garden; commercial garden or farm; botanical garden; park garden or farm^b; other.
Production type	Type of agricultural production (choose all that apply): food; fiber; ornamental; livestock; other; unknown.
Conservation type	Type of conservation application of study (choose all that apply): management effects = effects of a conservation or management practice; listed = a threatened, endangered, or other category of sensitive species; distribution = the documentation of habitat use; ...