Mary Gardiner
· Professor of EntomologyVerifiedOhio State University · Entomology
Active 1975–2026
About
Mary Gardiner is a Professor of Entomology at The Ohio State University. Her research focuses on entomology, with specific interests in insect biology and ecology. As a faculty member, she contributes to the academic and research missions of the department, engaging in teaching, mentoring, and scholarly activities related to entomology.
Research topics
- Ecology
- Biology
- Political Science
- Geography
- Sociology
- Environmental health
- Economic growth
- Mathematics
- Demography
- Environmental resource management
- Economics
- Forestry
- Environmental planning
- Statistics
- Chemistry
- Environmental science
- Zoology
- Business
Selected publications
Urban forestry & urban greening · 2026-03-28
articleOpen accessSenior authorClimate change is causing temperatures to rise across much of the earth, and this warming is amplified in urban areas due to the urban heat island effect. One of the most effective methods of reducing urban heat is expanding the urban forest. However, rising temperatures coupled with increasing drought intensity create challenges for the establishment of newly planted trees in cities. Obstacles to urban tree establishment are exacerbated in legacy cities, which have limited financial resources to plant and manage trees. In summer 2024, we conducted a large-scale field study in Dayton, Ohio, USA to address the challenges of expanding the urban forest in a legacy city. To determine low-cost solutions for urban forest expansion, we supplied 640 newly-planted native saplings with varying levels of irrigation investments across 20 parks in Dayton. We then monitored sapling survival, growth, and health in response to our irrigation investments and surrounding impervious surfaces within a 500-m radius of each planting site as a proxy for heat. We found that the effects of both irrigation treatment and surrounding heat varied among tree species. Overall, approximately 50% of planted saplings survived to the end of the growing season, and many saplings went missing due to anthropogenic disturbance. Therefore, we recommend a tailored approach to urban forest expansion which takes species, resources available for irrigation, and surrounding imperviousness into consideration to inform sustainable urban reforestation plans.
Unraveling urban biodiversity through citizen science
2026-03-10
articleOpen accessCitizen or community science is becoming an increasingly important component of biodiversity monitoring in cities. While the term is associated with a multitude of interpretations, citizen science involves the engagement of volunteers in the scientific process, with the goal of generating knowledge that addresses a relevant problem or research question. Citizen science has the potential to improve scientific literacy, facilitate experiences with nature, and provide valuable training for careers in STEM. Outside of direct benefits to volunteers, citizen science has yielded global biodiversity datasets, species discoveries and rediscoveries, and early detections of invasive species. As urban areas grow, citizen science presents even more opportunities to monitor and conserve biodiversity in cities. In particular, urban ecologists have paid increasing attention to engaging audiences not traditionally represented in ecology. Lack of adequate representation reinforces systemic inequalities, creates gaps in data, and leaves out research questions that are important to participating communities. By implementing an ‘ecology with cities’ approach, citizen science has immense potential to cultivate a more inclusive generation of scientists and advance urban ecological knowledge. Thus, assessing the status of urban citizen science projects and how they engage volunteers is of critical importance. Herein, we review over 400 citizen science projects monitoring urban biodiversity globally. We describe the breadth of urban citizen science (CS) projects which monitor biodiversity in terms of their scope, scale, and aims; the variety of approaches employed for biodiversity monitoring; and the audiences targeted for participation in urban CS projects. Finally, we present case studies representing a range of geographic and cultural contexts to illustrate the various challenges and opportunities associated with improving representation in urban CS projects. We summarize recommendations informed by these case studies that citizen science practitioners can use to inform their own efforts to reach audiences not traditionally represented in ecology. We chart out future research directions for citizen science to innovate community-engaged research methods, promote conservation, and advance biodiversity monitoring in cities.
Figshare · 2026-04-10
datasetOpen accessSenior authorData for study examining light pollution and urban warming on diapause in the Northern house mosquito <i>Culex pipiens</i>
Figshare · 2026-04-10
datasetOpen accessSenior authorData for study examining light pollution and urban warming on diapause in the Northern house mosquito <i>Culex pipiens</i>
Ecological Entomology · 2025-10-09
articleSenior authorAbstract Legacy cities often encompass large numbers of vacant land parcels that can be managed as greenspace to promote biodiversity and provision ecosystem services. Understanding the forces that shape arthropod predator communities within urban greenspaces is key to advancing sustainable landscaping programs targeted at promoting biodiversity. Our aim was to understand how the frequency of mowing and the extent of landscape fragmentation surrounding a vacant lot habitat influenced predator diets and shaped predator communities. We focused on a group of small web‐building spiders, as their dispersal success can be influenced by landscape variables, and their establishment is sensitive to local management intensity. We hypothesized that reduced landscape fragmentation and mowing frequency would sustain a species‐rich and abundant community of these generalist predators by supporting a high dietary niche breadth and reducing exploitative competition, measured as dietary niche overlap. We found significant dietary niche partitioning among the spider species studied. We found support for our hypothesis that managing vacant lots with less frequent mowing results in a greater dietary niche breadth for web‐building spiders. Interestingly, at the landscape scale, dietary niche breadth was positively associated with impervious surface, which did not support our hypothesis. A higher spider dietary breadth and reduced dietary overlap within a sampled spider community were not positively associated with spider activity density or species richness within a habitat patch, as we predicted. Our findings suggest that reducing the mowing frequency of vacant lots could improve their habitat quality for spiders by supporting diverse and abundant prey. However, humans are unlikely to accept infrequently mown vacant lots, as these sites are often viewed as overgrown and messy by residents. Working with residents to green their occupied residential parcels is another option to add vegetation biomass and complexity for biodiversity in legacy cities. For instance, adding well‐maintained gardens, shrubs and trees can improve arthropod habitat quality while also meeting the expectations for urban landscape appearance held by many.
bioRxiv (Cold Spring Harbor Laboratory) · 2025-03-13
preprintOpen accessSenior authorAbstract Cities have been acclaimed as hotspots for bee biodiversity and potential conservation targets, leading to continued investment in urban pollinator plantings. However, newly created habitats are rarely assessed for their efficacy in supporting bee fitness or the extent to which bees use seeded wildflowers. We compared urban bee nesting in targeted “pocket prairie” pollinator plantings versus urban farms that were intended to support multiple ecosystem services in Cleveland, Ohio, USA. We used trap nests to evaluate nesting success of cavity nesting bees and pollen metabarcoding to determine whether bees collected pollen from seeded plantings during nest provisioning. Pollen DNA revealed most bee-collected pollen was from urban spontaneous vegetation (or “weeds”) in Fabaceae, especially Trifolium spp. We also found that urban farms harbored more native bee larvae than targeted pollinator plantings. Finally, when bee nests were situated in a landscape with greater greenspace connectivity, we observed more native bee larvae and greater plant diversity in bees’ nesting provisions. Collectively, these findings suggest that multi-service greenspaces like urban farms can provide important urban pollinator habitat, and greenspace value for bees is driven by resident weeds and greenspace configuration. Open Research Statement Data are not yet provided. Upon acceptance data will be archived in Dryad Digital Repository. Each applicable R package is cited in the text; no novel code is presented. Larval DNA sequences will be available through BOLD, Barcode of Life Data Systems; Pollen DNA reads will be available through Dryad; Raw ecological data (larvae abundance, bloom characteristics, landscape structure) will be available through Dryad. Highlights Exotic weeds are cavity nesting bees’ dominant pollen source in cities Pollen DNA improves foraging observations across a diverse urban matrix Native bee reproduction was greater in urban farms than pollinator plantings Multi-service urban farms can promote win-win conservation scenarios Greenspace connectivity modulates bee foraging and nesting success
Ecology and Evolution · 2025-04-01 · 6 citations
articleOpen accessSenior authorPollinators are exposed to metals while foraging in the landscape and accumulate detectable concentrations of trace metals within their bodies, although major exposure routes remain unclear. As nectar is the main source of food for pollinators, we analyzed trace metal content within floral rewards to identify if nectar contained detectable metals and may serve as an oral exposure route. Nectar from flowering plant species growing within vacant lots in the city of Cleveland, OH, USA was extracted using a centrifuge and tested for the metals arsenic, cadmium, chromium, and lead using ICP-MS. We collected volunteer flower species that are common pollinator forage plants. Nectar metal content varied by plant and metal species, but not by location. Nectar arsenic concentrations ranged from 0 to 8.44 μg/L, cadmium from 0 to 32.99 μg/L, chromium from 0 to 45.69 μg/L, and lead from 0 to 135.31 μg/L. The presence of these soil contaminants in nectar indicates that the uptake and concentration of metals within nectar resources is likely a major route of metal exposure for pollinators and nectar-feeding animals.
Planting native wildflowers improves vacant land as bee habitat in a post‐industrial city
Ecological Entomology · 2025-03-05 · 2 citations
articleOpen accessSenior authorAbstract As people leave post‐industrial cities in search of better economic opportunities, abandoned homes are demolished and transformed into vacant lots. These greenspaces have been demonstrated to provide habitat for urban wildlife and supply ecosystem services to communities. In the post‐industrial city of Cleveland, Ohio, USA, approximately 37% of the state's bee fauna (Hymenoptera: Apoidea) has been collected within vacant lots. Our goal was to determine whether planting native wildflowers (‘pocket prairies’) on vacant land would improve these sites as bee habitat. We hypothesised that pocket prairies would support a greater proportion of the regional bee species pool, represented by Metropark grassland bee communities in the suburban landscape, compared to unaltered vacant lots. Using pan traps and hand vacuums, we sampled bees in each treatment from June to September 2019. We collected 1087 bees representing 24 genera and 81 species. Bees visited over 30 floral species, including native wildflowers and urban spontaneous vegetation. Metropark grasslands supported a higher bee species richness and diversity than urban pocket prairies. Both Metropark grasslands and pocket prairies supported a higher bee abundance, diversity and species richness than urban vacant lots. Synthesis and applications : Despite the substantially smaller extent of the pocket prairies, these habitats supported a similar bee abundance to the Metropark grasslands. Bee foraging on seeded native forbs also increased from representing <5% to >60% of plant–bee interactions over the course of this project, highlighting the importance of habitat establishment for urban bee conservation. Our results suggest that greening vacant land can improve post‐industrial cities as bee habitat.
Landscape change and alien invasions drive shifts in native lady beetle communities over a century
Ecological Applications · 2024-08-27 · 3 citations
articleOpen accessSenior authorUnderstanding causes of insect population declines is essential for the development of successful conservation plans, but data limitations restrict assessment across spatial and temporal scales. Museum records represent a source of historical data that can be leveraged to investigate temporal trends in insect communities. Native lady beetle decline has been attributed to competition with established alien species and landscape change, but the relative importance of these drivers is difficult to measure with short-term field-based studies. We assessed distribution patterns for native lady beetles over 12 decades using museum records, and evaluated the relative importance of alien species and landscape change as factors contributing to changes in communities. We compiled occurrence records for 28 lady beetle species collected in Ohio, USA, from 1900 to 2018. Taxonomic beta-diversity was used to evaluate changes in lady beetle community composition over time. To evaluate the relative influence of temporal, spatial, landscape, and community factors on the captures of native species, we constructed negative binomial generalized additive models. We report evidence of declines in captures for several native species. Importantly, the timing, severity, and drivers of these documented declines were species-specific. Land cover change was associated with declines in captures, particularly for Coccinella novemnotata which declined prior to the arrival of alien species. Following the establishment and spread of alien lady beetles, processes of species loss/gain and turnover shifted communities toward the dominance of a few alien species beginning in the 1980s. Because factors associated with declines in captures were highly species-specific, this emphasizes that mechanisms driving population losses cannot be generalized even among closely related native species. These findings also indicate the importance of museum holdings and the analysis of species-level data when studying temporal trends in insect populations.
Cadmium Soil Contamination Alters Plant-Pollinator Interactions
SSRN Electronic Journal · 2024-01-01 · 1 citations
preprintOpen accessSenior author
Recent grants
Frequent coauthors
- 14 shared
Yvan A. Delgado de la flor
The Ohio State University
- 14 shared
Frances S. Sivakoff
The Ohio State University at Marion
- 12 shared
Christopher B. Riley
- 11 shared
Kayla I. Perry
The Ohio State University
- 11 shared
Katherine J. Turo
Rutgers, The State University of New Jersey
- 10 shared
Sarah B. Scott
University of Cambridge
- 9 shared
Douglas A. Landis
Great Lakes Bioenergy Research Center
- 8 shared
Matthew E. O’Neal
Iowa State University
Labs
Awards & honors
- 2024 Distinguished Professor of Food, Agricultural, and Envi…
- 2024 Senior Faculty Research Award, Ohio State College of Fo…
- 2023 Nan-Yao Su Award for Innovation and Creativity in Entom…
- 2023 Distinguished Alumnus Award, Michigan State University…
- 2019 Junior Faculty Research Award, Ohio State College of Fo…
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