Welcome to FW 403 (001) Fall 2025 Urban Wildlife Management
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- Urban Waterfowl Population Management
Overview & Background: In the peer-reviewed journal article Urban waterfowl population: Ecological evaluation of management and planning (Greer, 1982), we see urban ducks observed and studied in order to determine early morning congregation habits and location. This study followed these populations, which consisted primarily of mallards, in Puyallup, WA. As we see more and more urban development in areas with adjacent rural habitats, waterfowl and other vertebrates are forced to adapt to stricter conditions. In these areas, waterfowl struggle with several habitat-related issues, such as habitat size and nesting condition/success. Many factors play into these aspects of survival in urban environments. Without proper habitat size or conditions that resemble the complexity of more rural areas, we see less species diversity.
Methods: The researchers took vegetation surveys and waterfowl counts in four locations in the Washington area. The four locations were: Dairy Stream, Pumphouse, Dairy Lagoons, and DeCoursey Pond. The vegetation surveys showed an abundance of reed canarygrass, turf grass, and pasture grass. Cover, frequency, and dominance were values that Greer calculated from these surveys. Along with the vegetation sampling, there were waterfowl head counts and monitored nesting success observations. Over the course of 14 months, Greer counted and collected data on the number of waterfowl found in these four locations at predictable times in the morning. The Shannon Index was used to determine the species diversity in these areas. For statistical analysis, ANOVA, Duncan’s multiple range test, and discriminant and cluster analysis were utilized.
Results: Over the course of the survey, Greer observed 13 different species of waterfowl, with mallards being the most abundant. They were also found to be the only species nesting locally. Other species, such as American wigeon, bufflehead, scaup, and gadwall, were present seasonally but did not nest in the study area.
The Dairy Stream location was somewhat supportive of several species such as mallards, wigeons, and buffleheads. However, the most supportive location was DeCoursey Pond. It had the highest species diversity and supported both dabbling and diving ducks due to the pond’s size and complexity compared to the others. The Dairy Lagoons primarily housed mallards, with low diversity for other species, though diversity improved slightly when mallard numbers were less dominant. Finally, the Pumphouse had the lowest species richness and was mostly dominated by mallards when feeding occurred. There was very little nesting success overall, and nesting was only attempted by mallards. This was due to low nesting cover, disturbance, and intraspecific aggression from other mallards. In all, DeCoursey Pond was the most complex and deep site, resembling rural environments that waterfowl were more adapted to, which provided a greater opportunity for them to thrive. By contrast, the lower diversity areas such as the Pumphouse were more frequently disturbed by humans and interfered with the natural behavior of more sensitive species.
Reflection/ Critique: After reading over the study and its findings, I have a few comments and possible improvements. I thought the vegetation sampling was conducted well and helped contextualize the environments these waterfowl were around and what they were interacting with. This gives clues to how and why species diversity might be so different in one area compared to the next. However, one area I thought was understudied was the possible predator or human interaction with the waterfowl. Predators, especially urban wildlife predators, could be a significant factor influencing lower species diversity in some locations. If predators were observed, one could determine if this was a factor in the counts of waterfowl in these areas. Artificial feeding also seemed to alter species composition at the Pumphouse, and this might have been worth more systematic study. For the most part, I thought it was a great survey that was done several decades ago but still represents a classic observation-based study that gives insightful data for those looking at how waterfowl might use urban corridors to live in.
Citation:
Greer, D. M. (1982). Urban waterfowl population: Ecological evaluation of management and planning. Environmental Management, 6, 217–229. https://doi.org/10.1007/BF01866885 - Flow in culverts as a potential mechanism of stream fragmentation for native and nonindigenous crayfish species
Background and Overview:
As the amount of urban area increases, habitat fragmentation becomes a bigger and bigger issue for many species. Crayfish are important members of aquatic ecosystems; they serve as a source of food for many other species, they are efficient detritivores, and their tunneling behavior can heavily influence the banks and beds of the streams they live in. They are also suffering from a worldwide decline in population, due primarily to a combination of habitat fragmentation and the introduction of invasive species of crayfish. This study primarily focuses on how culverts in rivers and streams affect two native populations of crayfish in Michigan, Orconectes virilis and Orconectes propinquus and their invasive counterpart, Orconectes rusticus. If O. rusticus is better able to traverse culverts than native crayfish, these barriers would allow O. rusticus to outcompete native species, further contributing to their possible extinction.
Methods:
The area of study for this project was the Carp Lake and Maple River watersheds located in Northern Michigan. Water velocity of 26 culverts at 11 different road crossings was measured and compared to water velocity ~50 meters upstream from the crossing. Velocity was measured 5mm above the stream/culvert bed to accurately reflect conditions that crayfish experience. The only species out of the three that was commonly found near the test culverts was O. propinquus, and its behavior in culverts was measured at three different flow velocities (2, 31, and 42 cm/s). A single crayfish per trial was placed at the starting location and observed for ten minutes or until it moved a meter away. Its location was marked every 30 seconds as well as the number of times the crayfish slipped as it traveled down the culvert. A “slip” refers to an involuntary movement downstream. Each crayfish was only tested once. To compare all three species to one another, a culvert in the Carp River was chosen, and the same process with O. propinquus was repeated with O. virilis, O. rusticus, and O. propinquus. Conditions were altered in the culvert with the creation of a debris dam upstream. To determine the impedance velocity, or the velocity of water at which the crayfish can no longer travel upstream, a flume was constructed in a lab using a propellor and a rubber mat to mimic conditions in a culvert.
Results:
Flow velocity in culverts was significantly higher than flow velocity in the rivers before the culvert. O. propinquus was found to alter its movements at different flow speeds. No crayfish slipped when the flow velocity was 2 cm/s, and more slipped at 42 cm/s than 31 cm/s. Smaller crayfish took longer to complete the trial at higher velocities than larger crayfish did. In order to test the theory that O. rusticus was better able to cross culverts than its native counterparts, all three crayfish species were tested in a culvert to gauge how successful they were at moving 1 meter in 10 minutes. O. rusticus and O. propinquus had fairly similar success rates and trial times, but O. virilis had a significantly harder time traversing the culverts. However, O. rusticus had an average impedance velocity that was several cm/s higher than that of the other two species. In general, larger crayfish had higher impedance velocities than smaller crayfish did.
Reflection and Critiques:
Overall, it seems like culverts will impede certain crayfish more than others, which is true of all types of aquatic animals. While it doesn’t seem like culverts will lead to the extinction of all native crayfish species, it is concerning that there are varieties of crayfish that fair significantly worse in culverts than others. Since crayfish are fairly limited in the ways they can move (by flipping their tail and crawling) they do have a harder time adapting to conditions in culverts than fish might. Most literature focuses around how freshwater fish can move through culverts, so I think that more research into how benthic organisms are affected is important. It is also difficult to say how crayfish from different parts of the US and different water conditions will be affected. I think that future research into crayfish found in different types of streams might be helpful; crayfish found in fast-flowing water might have a better chance at navigating culverts than those in wider, slower streams. One question that I have pertains to the matter of how crayfish are getting into the culverts. The study mentioned that some culverts were elevated above the river, which seems like it would pose an additional obstacle for crayfish. The study also does not account for dry culverts. Ultimately, I think it’s a good study, there are just a few gaps I think need closing.
Foster, H. R., & Keller, T. A. (2011). Flow in culverts as a potential mechanism of stream fragmentation for native and nonindigenous crayfish species. Journal of the North American Benthological Society, 30(4), 1129–1137. https://doi.org/10.1899/10-096.1
- Managing an Urban Landscape with Pollinators in Mind
Overview
The article I reviewed is Enhancing pollination supply in an urban ecosystem through landscape modifications by Davis et al. (2017), published in Landscape and Urban Planning. As urban farming becomes more common, understanding how to support pollinators in cities is increasingly important. This study examines whether converting small portions of turf grass into flowering habitat could increase pollinator supply and benefit urban agriculture. The researchers used Chicago, Illinois, as their study area and focused on modeling how different strategies for increasing floral resources, such as planting flowers in city parks, residential yards, or near community gardens, would impact pollination availability. The goal was to help city planners and residents find the most effective way to support pollinators and improve crop yields in urban gardens.
Methods
The researchers first mapped the locations of urban farms, community gardens, and home food gardens using Google Earth imagery. They then collected pollinator specimens from 15 community gardens across Chicago using colored pan traps filled with a detergent solution. Traps were arranged in a 3 x 3 meter grid, spaced one meter apart, with alternating colors, and left out for one daylight cycle each month during July, August, and September 2009.
Specimens were preserved in ethanol and later identified to genus or species. Using this field data, the team validated the InVEST pollination model, which uses land cover, nesting resources, and floral resources to predict pollinator abundance. They then modeled several scenarios simulating the conversion of one to five percent of Chicago’s turf grass to pollinator-friendly flower gardens in different locations, including city parks, private yards, and areas within varying distances of community gardens, to compare how each strategy affected pollination supply across the city.
Results
The study found that augmenting floral resources can increase pollination supply in Chicago, but the most effective strategy depends on the type of urban agriculture. For home gardens, distributing flowers throughout the city was most beneficial, while concentrating flowers near community gardens and urban farms provided the greatest pollination benefits for those larger sites. The InVEST model predicted 46 percent of the variation in native bee richness, indicating that it can reliably identify areas with high or low pollination potential. The results highlight that city parks, forest preserves, and green spaces act as pollination hotspots, whereas downtown and heavily industrialized areas may have lower pollination supply.
Fig. 1. Study area (Chicago, Illinois)with inset of United States.
Fig. 2. Map of pollination supply score and location of sites used for model validation, i.e. sites where bees were collected.
Fig. 4. Effect of landscape modification scenarios on pollination supply scores.
Critiques and Reflection
While this article provides valuable insight into the role of bees in urban pollination and demonstrates how modifying turf grass can enhance pollinator supply for both residential and commercial agriculture, it has some limitations. One notable omission is the lack of consideration for other important insect orders, such as Diptera (flies) and Lepidoptera (butterflies and moths), which also play critical roles in pollination. Including these groups could provide a more complete understanding of urban pollinator communities.
The study excels in highlighting the underutilized potential of urban green spaces, particularly turf grass and ornamental plantings, and shows how thoughtful landscape modifications can provide both ecological and economic benefits. However, greater attention could be given to the use of native plantings, which not only offer nectar resources but also serve as host plants for pollinators, contributing to the restoration of urban biodiversity and supporting the life cycles of native insects.
Despite these limitations, the article provides strong empirical evidence for the importance of maximizing the ecological value of urban green spaces. It demonstrates that targeted interventions, such as converting portions of turf grass to flower gardens, can meaningfully enhance pollinator populations and improve urban agricultural productivity, making it a valuable resource for both researchers and urban planners.
Reference
Amélie Y. Davis, Eric V. Lonsdorf, Cliff R. Shierk, Kevin C. Matteson, John R. Taylor, Sarah T. Lovell, Emily S. Minor. (2017). Enhancing pollination supply in an urban ecosystem through landscape modifications, 162, 157-166. https://doi.org/10.1016/j.landurbplan.2017.02.011
- Reconciling cities with nature: Identifying local Blue-Green Infrastructure interventions for regional biodiversity enhancement.
This study, “Reconciling cities with nature: Identifying local Blue-Green Infrastructure interventions for regional biodiversity enhancement,” was written by Donati et al. and published on August 15th, 2022. It seeks to answer the question of how we can better support regional biodiversity enhancement in cities through local Blue-Green Infrastructure (BGI) interventions. To address this, the researchers focused on how amphibian species are affected by urbanization, using the Swiss lowlands as a case study. Amphibians were chosen because they are particularly sensitive to environmental conditions compared to most other animal groups and because they depend on both terrestrial and aquatic habitats.
The researchers approached this question using habitat suitability models, high-resolution land cover data, and circuit theory models to assess biodiversity patterns in both urban and non-urban areas. In identifying the key habitat features that best support regional biodiversity enhancement, they found that stepping-stone areas allowing amphibians to move between habitats were the most important. The study highlighted features such as forest edges, wet forests, moist soils, and riparian habitats. From this, the researchers concluded that up to 15% of urban spaces could contribute to regional ecological connectivity if strategically planned and intentionally managed. Overall, the study shows that cities, if designed with biodiversity in mind, have the potential to significantly enhance ecological connectivity and support regional biodiversity.
This study is well-written and highly credible, being peer-reviewed and supported by a substantial amount of evidence. It does an excellent job of presenting its research, providing clear justification for its methodology, reasoning, and results. The focus on amphibians is particularly strong, as the authors clearly explain why this group was chosen and how it effectively demonstrates the value of biodiversity in urban contexts.
However, the study struggles somewhat with connecting its findings explicitly to the concept of BGI. BGI is often understood as engineered infrastructure—such as green roofs or rain gardens—designed to improve environmental outcomes in human-made spaces. In this study, however, BGI is framed more broadly, referring to the modification of human-used landscapes to support natural habitats and species. While this is a valid interpretation, the distinction could have been made clearer. Another limitation is the narrow applicability of the findings. Although amphibians are highly sensitive to anthropogenic impacts, results derived from their responses cannot be easily generalized to other species, such as birds or small mammals. This limits the study’s broader ecological relevance.
I personally found this study extremely interesting and eye-opening, particularly in its approach to using natural habitat features as a form of Blue-Green Infrastructure—an area of habitat management I had not previously considered. While this type of infrastructure was new to me, the results confirmed some of my assumptions about regional biodiversity enhancement in cities and also provided surprising insights. I was impressed by the depth of evidence presented, including the various mapping strategies that show cities can increase amphibian connectivity by up to 15% if key habitat features are intentionally incorporated. From this study, I have gained not only a better understanding of BGI but also an appreciation for the optimistic potential cities have to enhance biodiversity when environmental considerations are prioritized in infrastructure planning.
Overall, I found this study to be compelling and thought-provoking, proposing important ideas supported by strong data. While the study is well-executed in terms of methodology and reasoning, it does have some limitations. For instance, certain conceptual elements could have been expanded to make the findings more broadly applicable to other species and urban contexts.
The study effectively conveys its central message: cities can improve environmental conditions and support regional biodiversity if planners actively consider ecological factors in infrastructure design. Nevertheless, the work is far from exhaustive. Future research could explore how these interventions affect other species, such as birds or small mammals, and investigate practical strategies for implementing BGI in existing urban areas. Additionally, examining how cities can retrofit current infrastructure to better support biodiversity would further enhance the study’s practical relevance.
Donati, G. F. A., Bolliger, J., Psomas, A., Maurer, M., & Bach, P. M. (2022). Reconciling cities with nature: Identifying local Blue-Green Infrastructure interventions for regional biodiversity enhancement. Journal of Environmental Management, 316, 115254. https://doi.org/10.1016/j.jenvman.2022.115254
- The Case of Urban Deer
The article I have selected is called “A Review of Urban Wildlife Management from the Animal Personality Perspective: The Case of Urban Deer.” This article focuses on reviewing human-urban wildlife conflicts in Japan and North America, as well as approaches to take animals’ personalities into account to help improve urban-wildlife conflicts. In North America, the most common issues with wildlife in urbanized areas are zoonosis and wildlife-vehicle collisions. Deer are the most problem-causing. The article focuses on understanding the behavior of species and what could be a possible cause of wildlife entering urban areas and causing human-wildlife conflict. Boldness was found to be heritable, which means their ability to not be so shy is a bit genetic. According to studies cited in the article, bolder deer are more likely to enter urban areas, where they can exploit food sources and interact more frequently with humans, increasing the risk of conflict. In Japan, data showed that deer in high-conflict areas were consistently bolder than those in rural regions, suggesting a behavioral link to urban presence. The author suggests considering the genetic components of boldness when searching for control measures. In Japan, bolder deer were found to inhabit urban areas and heavily rely on humans for food, which has led to human-wildlife conflicts. Although there are benefits to continuing to build urban areas while allowing deer to coexist with humans, the idea of selecting for bolder deer, in my opinion, sounds potentially dangerous, as bolder deer could lead to serious problems. By incorporating the concept of animal personality, it opens the door to more targeted, possibly more humane strategies for managing urban wildlife.
https://www.sciencedirect.com/science/article/abs/pii/S0048969718324112