Identification of mammal species preyed upon by urban foxes (Vulpes vulpes) in Sapporo, Japan, determined by fecal DNA analysis

Posted on by Clay Sebastian

Overview

This study focuses on investigating the diet composition of red foxes (Vulpes vulpes) living in urban areas in northern Japan. Red foxes rely on varying food sources, including several types of small mammals and fruits. This study suggests that the home range of urban foxes can be around 30 hectares, so they have a large area to forage for food in. This paper looked at the types of small mammals that the urban foxes were consuming by analyzing scat samples. The species of animals being consumed by urban foxes was determined by extracting DNA from the scat samples that were collected. The advantages of fecal DNA analysis include non-invasiveness, ease of collection, and high accuracy. The goal of this analysis is to understand the diet of urban red foxes in northern Japan, specifically what animals they are consuming.

Methods:

The ‘urban areas’ that were included in this study had to be considered densely inhabited districts by the Statistics Bureau of Japan. The ‘suburban areas’ in this study were areas that were in the city but outside of densely inhabited districts. One challenge for sample collection was distinguishing the scat of urban foxes from that of other species such as dogs. This was solved by using polymerase chain reaction (PCR) to test for primers that were specific to red foxes. This allowed the researchers to ensure that their samples were actually coming from urban foxes. The researchers also had to develop PCR primers for the species they were testing for in the red fox scat. The wild species that had PCR primers developed for them were gray red-backed vole, Hokkaido red-backed vole, northern red-backed vole, large Japanese field mouse, small Japanese field mouse, brown rat, house mouse, Eurasian red squirrel, Siberian chipmunk, mountain hare, and sika deer. Additionally, the researchers also used PCR primers to test for the presence of livestock species in the urban fox scat (cattle, pig, and chicken). The development of the PCR primers for prey species was essential for allowing the researchers to analyze the scat samples from the urban foxes.

Results:

In total there were 110 scat samples collected, and 78 of them were determined to come from red foxes (these 78 were used for the analysis). The wild mammals that were tested for were found in 47.4% of the samples. The gray red-backed vole was the most commonly detected wild mammal species, and it was found in both urban and suburban samples. Other commonly detected species were the brown rat and the large Japanese field mouse. Interestingly, the mountain hare, house mouse, Hokkaido red-backed vole, northern red-backed vole, and small Japanese field mouse were not found in any of the samples that were collected. When looking at the dietary composition of livestock, chicken was most commonly found in the scat samples (56% of samples contained chicken). Pig was also commonly found in the samples (29% of samples contained pig). Although cattle were not found as commonly, the total frequency of livestock in the urban fox scat samples was 61.5%. Additionally, multiple prey species were found in 38% of the samples.

Reflection/Critiques:

Wild mammals play an important role in the diet of urban red foxes in the study area. The primary wild mammal prey species for urban foxes in this area was determined to be the gray red-backed vole. This was supported through wild mammals being found in 47.4% of samples and the gray red-backed vole being found in 30.2% of samples. Although it is possible that the urban foxes were feeding in different areas than where they were dropping feces, the researchers concluded that this was unlikely due to the home range size of the red foxes. The brown rat was also found to be an important dietary component for the urban foxes. This was likely due to the high abundance of this species in cities (brown rats can take advantage of the urban environment). Sitka deer was only found in one scat sample. This was likely from a scavenged carcass since sitka deer are a much larger mammal species. Overall, wild mammal species are an integral part of the diets of urban red foxes in the study area.

Livestock species were found in a larger percentage of the fecal samples for urban red foxes when compared to wild mammal species. According to this study, livestock species were found in 61.5% of the collected scat samples. This suggests that livestock species play a crucial role in supporting the diet of urban foxes. It is likely that this dietary component was primarily sourced from human garbage due to the urban location. The livestock species that was most commonly found in urban fox diets was chicken. This is likely due to it being frequently discarded in garbage. This area of Japan has higher average pork consumption when compared to cattle. This explains why pork was found more frequently in urban fox scat when compared to cattle. Overall, anthropogenic food sources are very important to the diets of urban red foxes in the study area.

The primary critique I have for this study is the relatively small sample size of urban red fox scat. The researchers only analyzed 78 scat samples. If the number of samples were increased, then the conclusions that the study found would be more reliable. The researchers could have greater confidence in the new discoveries regarding the dietary composition of urban red foxes in the study area. Although this would have required more input, the researchers had a reliable method to distinguish the red fox scat from other species.

Another critique for this study is the choice to collect samples without any way of identifying which individual fox they came from. This could have an impact on the data if multiple samples were collected from the same individual fox. It would be beneficial to have a method of quantifying the number of different individual foxes that contributed samples to the study. It would also be beneficial to know the number of samples that came from each individual fox. This would improve the analysis since the diet of each individual is variable and unique. Although this would improve the study, it is likely not practical. Monitoring individual foxes would be difficult, time consuming, and costly. It would also be difficult to attribute particular scat samples to individual foxes.

Reference:

Waga, D., Amaike, Y., Nonaka, N., & Masuda, R. (2025). Identification of mammal species preyed upon by urban foxes (Vulpes vulpes) in Sapporo, Japan, determined by fecal DNA analysis. The Journal of veterinary medical science, 87(8), 960–965. https://doi.org/10.1292/jvms.25-0199

Critical Review of “Urbanization Effects on Spotted Salamander and Wood Frog Presence and Abundance”

Posted on by Jada L Lee

Overview

This study by J.M. Reed and colleagues, published in Urban Ecosystems, explores how urban development influences the presence and abundance of two amphibian species: the spotted salamander (Ambystoma maculatum) and the wood frog (Rana sylvatica). Both species rely on temporary woodland pools, known as vernal pools, for breeding. Because amphibians are highly sensitive to environmental changes, they serve as indicators of ecosystem health. The researchers aimed to determine how surrounding land cover, such as forest area, impervious surfaces, and road proximity, affects amphibian occurrence and breeding success in human-altered landscapes.

Methods

Reed and his team surveyed 41 vernal pools in central Massachusetts that represented a range of surrounding land uses, from heavily forested to highly urbanized areas. They measured egg mass counts to estimate breeding abundance and recorded environmental factors including forest cover within 100–300 meters, hydroperiod, road density, and impervious surface area. To evaluate which factors most influenced amphibian presence, the researchers used logistic regression and stepwise model selection.

A key strength of the study was its use of GIS data to quantify the surrounding landscape, offering more precision than visual observation alone. However, one limitation was that data collection occurred during a single breeding season. The authors noted that year-to-year differences in rainfall and hydroperiod could influence amphibian breeding success, meaning a longer-term study might reveal additional trends or variability.

Results

The study found a clear negative relationship between urbanization and amphibian presence. Spotted salamanders were observed in 69 percent of pools with over 75 percent surrounding forest, but in fewer than 20 percent of pools where forest cover was below 25 percent. Wood frogs showed a similar pattern, though they appeared somewhat more tolerant of moderate development.

Road density within 100 meters of pools was one of the most consistent predictors of absence. Roads not only fragment habitats but also increase adult mortality as salamanders and frogs migrate to breeding sites. In addition, the amount of impervious surface near pools was strongly linked to lower abundance, likely due to disrupted hydrology and reduced water quality. The authors pointed out that even small increases in pavement or built infrastructure can lead to disproportionate ecological effects, illustrating how sensitive amphibians are to habitat loss and fragmentation.

Reflection / Critique

This study presents convincing evidence that urbanization substantially reduces amphibian populations, but there are several aspects that could have been expanded upon. While the authors recommend maintaining at least 30 to 50 meters of forest buffer around vernal pools, they do not provide practical guidance on how these recommendations might be implemented through zoning or conservation policy. Including examples of towns or municipalities that have successfully integrated amphibian habitat protection into land-use planning would have made the research more applied and actionable.

Another limitation is the lack of direct water quality data. The authors mention that pollution from runoff could influence amphibian populations, but they did not measure chemical variables such as nitrogen, phosphorus, or heavy metals. Without this information, it remains uncertain whether declines were driven primarily by habitat fragmentation or by contamination of breeding pools. Future studies combining both land-use and water chemistry analyses could paint a fuller picture of how urbanization impacts amphibians.

Even with these limitations, the study makes a valuable contribution to urban ecology. The finding that spotted salamanders virtually disappear when impervious cover exceeds 25 to 30 percent provides an important threshold for conservation planning. The authors also highlight how both landscape connectivity and small-scale features like forest buffers can make a major difference in sustaining amphibian populations.

Overall, this research offers a strong reminder that sustainable development must consider the needs of species that rely on small, seasonal, and easily overlooked habitats. Amphibians like the wood frog and spotted salamander are not just victims of habitat loss but also indicators of how human choices shape the health of entire ecosystems.

Reference:
Reed, J. M., et al. (2005). Urbanization Effects on Spotted Salamander and Wood Frog Presence and Abundance. Urban Ecosystems

What can we learn from wildlife sightings during the COVID-19 global shutdown?

Posted on by Madeleine Elisabeth Rueckeis

Introduction

The global lockdown beginning in 2020 allowed some wildlife to venture into cities, like foxes, coyotes, and birds. The paper “What can we learn from wildlife sightings during the COVID-19 global shutdown?” by Zeller et al. (2020) in Ecosphere encompasses both an ecological and social study. The author uses citizen science data to explore changes in wildlife observations during the pandemic. This paper caught my attention due to the discussion in class about the pause in human activity during the pandemic and how urban wildlife behavior is intertwined with our presence.

Summary

Zellmer and colleagues analyzed citizen reported wildlife sightings from platforms like iNaturalist and eBird, comparing data from the early months of the pandemic to previous years. The purpose was to figure out whether wildlife actually became more abundant in cities during lockdown or if people only noticed a greater abundance of animals because they were at home and actually paying attention.

Results

They found mixed evidence. Reports increased of wildlife sightings in many urban areas, but this does not mean that there were necessarily more animals. Species that appeared more frequently in urban environments were coyotes, deer, and foxes. These were species that typically avoid dense human spaces. The paper emphasized that changes in behavior varied by species, city, and the degree of lockdown strictness. They ultimately, highlighted, that human movement can drastically alter the visibility and distribution of urban wildlife. A big portion of the paper is dedicated to acknowledging what the data cannot prove due to observer effort bias, detection vs. abundance, and heterogeneity among cities. The article never comes to an exact conclusion that wildlife increased in urban areas during lockdowns, but rather raises possibilities and promotes cautious interpretation.

Critical Reflection

This study is strong in that it used this rare global event as a large-scale natural experiment. The use of citizen science allowed for fast data collection and broad spatial coverage during a difficult time. The article is also rightfully cautious in not claiming “nature reclaimed cities” and instead acknowledging biases in observation and sampling. This underlines that this study is more of an analysis of human behavior rather than animal abundance. All in all this reflects on their credibility, making it a more reliable source. However, the authors could have gone further in correcting biases, rather than simply acknowledging it. For example they could have implemented observation models and categorization, which could have helped them separate real life wildlife increases from high detection rates. Furthermore, the study focuses on the early stages of lockdown in 2020, when in reality animals responses to the lockdown evolved over time. A study comparing all years of lockdown would test whether behavioral flexibility persists. Further studies could combine citizen science with automates monitoring, such as camera traps, sensors or tracking collars. Additionally, comparing results across continents could reveal cultural or infrastructural influences on how wildlife adapted depending on the density of buildings, size of city, noise pollution etc.

Work Cited

Zellmer, A. J., Wood, E. M., Surasinghe, T., Putman, B. J., Pauly, G. B., Magle, S. B., Lewis, J. S., Kay, C. A. M., & Fidino, M. (2020). What can we learn from wildlife sightings during the COVID-19 global shutdown? Ecosphere, 11(8), e03215. https://doi.org/10.1002/ecs2.3215

Microbial diversity and community respiration in freshwater sediments influenced by artificial light at night

Posted on by Sean Allen Ravenberg

Background: The purpose of this study was an analysis of the impacts of light pollution on benthic microbial populations. The researchers state how these kinds of microbial populations are populous all over the planet and are highly diverse. They hypothesized that artificial light pollution will affect the composition and behavior of these populations and therefore will change ecosystem dynamics, affecting the global carbon cycle. The study was designed to take two similar benthic microbial populations and expose one to artificial light at night for six months and have the other in natural conditions to see whether this was true, and what effects this artificial light would have on the communities and their processes. 

Methods: The study was conducted by identifying two sites of benthic microbial organisms, two agricultural drainage ditches. The team verified that moisture levels were near identical for both sites, and also established that the species and populations were biologically similar enough for their study. They did this through DNA metabarcoding and included these results in the study to verify that their two populations were suitable for experimentation. These sites were located in a verified Dark Sky zone to confirm that the control would not experience any artificial light at night. One site was therefore chosen as a control and would receive no treatment, and the other site had artificial lamps installed over it. The lumens of the treatment for this site were also measured and controlled to be similar to the average lumens experienced in other urban settings that experienced artificial light at night. This data was also included in the study to verify that treatment levels were significantly similar to actual experienced light levels. Then, the light was maintained over the treatment site for six months. At the end of this time period, biological information about population composition, cellular respiration, and carbon sinking were recorded. 

Results: The study returned results that photosynthetic autotrophic organisms saw statistically significant population growth and comprised a larger percentage of the benthic ecosystem in the site that received treatment than in the one that didn’t. They also detected that cellular respiration levels had decreased. Overall this indicates a decrease in species diversity as the benthic communities were made to shift towards auto phototrophic majority populations, however they did anticipate that this could eventually lead to net positive NEP in these kinds of communities as light levels at night increase over time. This answers one major question of the experiment, which was whether or not light levels at night, significantly lower in intensity than sunlight, would be enough to stimulate photosynthesis for these benthic autotrophic organisms. 

Criticisms: I think that this experiment was set up very well. They accounted for many factors that could affect the results of their work and took data measurements to ensure that these factors were mitigated as much as they could be to establish reliable results. The difference in species between locations were accounted for by the DNA metabarcoding to ensure a similarity of species richness. The moisture levels were accounted for by testing to ensure similarity, and the lumen levels of the control site were measured to ensure they met natural dark sky levels to establish significant differences if they appeared. I think that all these precautions show a lot of forethought in the experiment and help to establish credibility of the results. I do think that perhaps they are extrapolating a bit much about the results in the discussion portion. They claim that the results of their experiments are proof that increasing light levels at night in the world will turn benthic organisms into ecosystems of net positive production at night year round, and that this will affect carbon sinking on a global scale. All this experiment really proved is that a long term presence of artificial light at night increased photosynthetic production in this one treatment group. I think these claims they make in their discussion are reasonable hypotheses and absolutely excellent grounds for future experimentation, but not truly establishable from this experiment alone. 

https://royalsocietypublishing.org/doi/full/10.1098/rstb.2014.0130

Decline of the Green Salamander: Corser’s Study on Aneides aeneus

Posted on by Matthew Samuel Pugh


In Corser’s (2001) peer-reviewed article regarding Aneides aeneus, a green salamander species found in the Appalachian Mountains, he found that the species suffered critical population declines during different periods spanning across multiple decades. The first decline was noticed in the 1970s, with another major decline found in the late 1990s. Corser attributed these population losses to habitat destruction, overcollection, climate change, and epidemic diseases.

Most amphibian species that have declined in North America are those found in mountainous regions experiencing localized population decreases. These are typically isolated populations, separate from others, representing a localized population decline rather than a species-wide collapse. Additionally, other amphibian species outside of salamanders were found to have even worse population declines due to their (at the time) lack of understanding regarding salamander populations. During the 1990s, following reports of amphibian declines, many researchers were first introduced to the concept of amphibian decline as a present conflict in wildlife ecology (Corser, 2001).

This article focused on a specific species throughout the 1990s when this new issue was brought to the forefront of the wildlife conservation community. Corser chose to study Aneides aeneus, a green salamander found in the “Blue Ridge Escarpment” or BRE. The Blue Ridge Escarpment, according to VisitGreenvilleSC.com, is “the line at which…the Blue Ridge Mountain range plunges down towards the rolling foothills of South Carolina,” which illustrates the interesting ecological niche that these salamanders play a role in. According to Corser (2001), they “occupy one of the most specialized and xeric niches of any eastern salamander.” They live in crevices and short outcroppings along tributaries and gorges of the BRE.

Due to the increased observation of salamander decline apart from the first observed drops in 1970, Corser (2001) chose to observe and collect data to determine the population sizes in the BRE. In areas found along the BRE in Georgia, North Carolina, and South Carolina, Corser located the previous scientist’s survey locations from the 1970 study and attempted to recreate the same observations. Corser found thirteen locations to monitor the green salamander populations, seven of which were exactly from Snyder (1971). This gave Corser both new and previous observational areas to research the rock crevices for brooding females. This method was proven to be significant for Snyder’s (1971) research. Corser surveyed these areas once a year from 1991 to 1999, during the last week of July or the first week in August. This provided a great opportunity to locate brooding females and estimate both population size and fecundity.

By using the MONITOR Monte Carlo linear regression model, Corser (2001) was able to determine that the population decline at the historic sites from Snyder’s (1971) paper remained low and continued to decline. In contrast, the new populations found during the 1991 to 1999 survey period were not significantly declining when compared to the already decimated populations from the 1971 observations.

Finally, Corser (2001) was able to conclude that a myriad of factors—whether that be clear-cutting, habitat loss, increased levels of DDT in salamander systems, or other anthropogenic influences seen in nearby amphibian species—might be contributing to the decline and lack of population rebound. With the limited number of sample sites and a rejection of the null hypothesis for the green salamander populations, one could conclude that there are likely many unknown areas Corser was not able to find, since their ecological niche is so specific and difficult to locate within rock crevices. If more samples were found and observed over longer periods of time, future studies could see more significant results, one way or another. This could further prove that their populations are, in fact, declining and are unable to rebound from ongoing environmental and human-caused stressors.

References: Corser, J. D. (2001). Decline of disjunct green salamander (Aneides aeneus) populations in the southern Appalachian Mountains. Biological Conservation, 97(2), 119–126. https://www.sciencedirect.com/science/article/pii/S0006320700001002?via%3Dihub

Snyder, D. H. (1971). The function and evolution of brooding behavior in the plethodontid salamander Aneides aeneus. Copeia, 1971(2), 385–390. www.visitgreenvillesc.com/listing/blue-ridge-escarpment/6237/

Urban Biodiversity Indicators and Assessment Tools

Posted on by Ethan Horst Haneke

The study “Sustainability Assessment on an Urban Scale: Context, Challenges, and Most Relevant Indicators” by Salati, Maryam; Bragança, Luis; and Mateus, Ricardo, published in 2022, addresses the lack of consistency in indicators used to assess sustainability in urban environments. The authors highlight this as a significant issue, noting that the wide variety of indicators currently used globally often lack connectivity, which hinders efforts to advance sustainability on a global scale. If urban sustainability assessments can become clearer, more consistent, and more practical, they could become widely accessible and accepted. Such a universal approach could help guide local and global policymaking, supporting environmental protection and establishing standards to improve the health of urban ecosystems, benefiting both nature and people.

I found this article particularly interesting because of its perspective on how urban biodiversity indicators and assessment tools are utilized. I was especially drawn to its strong belief in the potential for improving policymaking and fostering healthier urban ecosystems, which in turn can contribute to a more sustainable and unified world for both humans and wildlife.

This research article is strong in several key areas. Its topic is intuitive and demonstrates a clear need for a solution, which immediately underscores its relevance. The paper emphasizes the potential for meaningful change, arguing that a standardized set of indicators could be directly applied to policymaking to improve sustainability in communities globally. The study also does an excellent job of laying out a structured methodology for identifying standardized urban biodiversity indicators. It carefully reviews the most common and practical measures currently used worldwide, explains their relevance, and clearly justifies their inclusion in the proposed set of indicators. Another notable strength is the study’s ability to address sustainability across environmental, social, and economic dimensions in a fluid and integrated manner, demonstrating the interconnected nature of this topic and its significance across multiple facets of urban life. Additionally, the authors acknowledge the need for adaptability, noting that urban environments are highly diverse and constantly evolving. They recognize that the framework may have gaps and that ongoing adjustments may be necessary to respond to rapid global changes. Overall, this article demonstrates many strengths, from its methodological rigor to its holistic approach, making it a particularly compelling and valuable study.

Despite its strengths, the study does have some important limitations. The most significant limitation is the lack of real-world data or testing. The study relies entirely on analyses of four existing assessment tools to evaluate urban biodiversity indicators. While the selected indicators are commonly used and relevant, there is no empirical data to confirm that they are the most effective in practice. Another limitation is its narrow scope; by focusing on only four assessment systems, the study cannot claim to provide global representation, which is important given the diversity of urban environments around the world. I also found a tension in the study’s goal of simplifying and standardizing assessments in their effort to create a framework that is more accessible, the authors grouped indicators into broad categories. While this approach is useful for generalization, it risks overlooking location-specific details that may be crucial depending on the urban context. In my view, this represents a hopeful but somewhat oversimplified approach to standardizing indicators, which may limit its practical application across highly variable urban environments.

Nonetheless, I believe this study is of great scientific and cultural importance. While its limitations are significant and should be addressed in future research, the study effectively highlights the challenges of connecting scientific knowledge with policymaking on a global scale. It uses analytical methods to determine which indicators are most frequently used and relevant, providing a strong foundation for standardization efforts. This study is an important stepping stone toward improved sustainability for current and future urban biodiversity, and its findings have the potential to positively influence both research and policy. For these reasons, I found this study exceptionally useful and inspiring.

Reference:
Salati, M., Bragança, L., & Mateus, R. (2022). Sustainability assessment on an urban scale: Context, challenges, and most relevant indicators. Applied System Innovation, 5(2), 41. doi:https://doi.org/10.3390/asi5020041

Addressing the challenge of wildlife conservation in urban landscapes by increasing human tolerance for wildlife in Atlanta, GA

Posted on by Kira Leigh Brown

https://www.proquest.com/docview/3064395118/9B10DEAE6BFE47A4PQ/7?accountid=12725&sourcetype=Scholarly%20Journals

This study examines how more frequent and often negatively perceived interactions with wildlife is worsening with urban expansion. This is important because wildlife conservation largely depends on human tolerance for wildlife. The study area was the Metropolitan Atlanta, which contains 5.9 million people 45% forest cover. They examined wildlife related calls with complaints related to wildlife in neighborhoods, sick injured or orphaned animals, and the rest pertaining to threats to humans, domestic animals or other conflicts. The study then goes into demographic distributions, racial inequality with environmental justice, and quality of green spaces. They designed an online survey with demographic and geographic questions (like zipcode/neighborhood definition), whether they owned pets, or had gardens and how often they were tailored to. They selected 15 species for reporting based on frequency of past reports, and those that were likely to elicit different reactions from participants. These were matched with attitude rankings and emotional responses to different animals, as well as whether they would prefer populations to change.

The results were as follows: a little over half of the respondents were female and black. 68% of respondents lived in a house and 67% with a garden. Respondents’ gardens often contained lawn and flowering plants, thereby providing habitat for urban wildlife. The most frequently reported conflicts were raccoons raiding trash cans, squirrels, chipmunks, rabbits and deer damaging landscaping, and vehicle collisions with deer. Respondents’ attitudes toward species were positive predictors of tolerance. For example, those who were mutualistic (value wildlife and human harmony) in their beliefs were also more likely to be tolerant of coyotes, deer, opossums, snakes etc. Those who had threatening experiences with these animals had less tolerance. As far as demographics go, black respondents were less tolerant of foxes but more tolerant of squirrels and chipmunks, while Hispanic respondents were less tolerant of owls and rabbits. This could be due to the green space difference in certain minority communities and the species they interact with.

The methodology clearly presents a range of possibilities for interactions, giving participants ample descriptions of wildlife scenarios as well as matching them to frequency of occurance. The wildlife value orientation scale from traditionalist to mutualist views gives clear context for how certain participants may have responded differently to the same wildlife interaction. Equal and intentional sampling of minority groups allowed for clear analysis and comparisons between groups. The main deficit of this study is the amount of factors being assessed at once and its reliance on other research. In the discussion, the references to other studies explained the relationships more in depth than most of the correlations found within the study. They unexpectedly found an inverse relationship between self efficacy (protection from wildlife) and snake tolerance. This may be a result of the design of self-efficacy statements, which were generic and not specific to each focal species. There must be more specific relationships defined and more focus on a few variables, like emotions and conflict interactions, as well as demographics for example.

Future research should focus on implementation of the Urban Wildlife Program and community science’s influence on people’s responses and attitudes. I think more research on green space distribution and other factors besides gardens (like canopy cover) in black and minority neighborhoods would give more insight into their tolerance levels and interactions. I would love to learn more about how minority communities may benefit from urban wildlife, or be disproportionately harmed by it.

This paper caught my eye because I think there are more effective ways of managing human-wildlife conflict that have not been addressed. While agencies typically focus on education and conflict mitigation, more proactively increasing wildlife tolerance may be a more effective long term strategy for conservation. Because prior conflicts with species rarely influenced tolerance, more focus should maybe be reinforcing positive emotions and interactions, as well as just more opportunities for communities to safely observe wildlife and their behaviors.

Urban Wildlife Connectivity and Habitat Conservation: Species of Conservation Concern in Michigan, USA

Posted on by Sam Schoenberg

Overview

I chose this article as it relates to urban wildlife management in the context of urban planning and optimizing cities for wildlife diversity and connectivity. The study focuses on locally rare species representing a wide range of taxa, offering insights into how urban areas can be designed to support biodiversity through habitat corridors. The authors evaluated patterns of habitat availability and connectivity for nine rare species: two insects, three turtles, two snakes, one bird, and one bat across four urban regions in Michigan, USA. These species were selected because they are regionally rare (ranging from state-listed to federally endangered) but still maintain populations within urbanized landscapes. The study aims to identify how urbanization influences habitat structure, connectivity, and opportunities for conservation planning.

Methods

The researchers selected nine focal species representing several taxonomic groups known to be regionally rare. Species occurrence data were compiled from multiple reputable databases, including the Michigan Natural Heritage Database (MNFI), the U.S. Fish & Wildlife Service (USFWS), HerpMapper, iNaturalist, and eBird. To ensure data reliability, only verified MNFI and Research Grade iNaturalist records were used, and records prior to the year 2000 were excluded. Protected areas were mapped by merging all federal, state, county, local, and NGO-managed lands from MNFI GIS layers, excluding disturbed greenspaces such as golf courses.

Urban boundaries were defined using U.S. Census Bureau criteria areas with populations over 50,000 and a density of at least 1,000 people per square mile, with adjacent tracts of 500 people per square mile included as urban periphery. This classification allowed the researchers to analyze habitats embedded within realistic urban-to-rural gradients. Connectivity analyses were then conducted within selected urban regions that met these demographic criteria and contained overlapping species occurrences.

To establish biologically relevant study sites, the team generated 5 km buffers around each species occurrence, encompassing estimated dispersal ranges for most taxa. Overlapping buffers within 10 km of each other were merged, and convex hull polygons were created around the merged clusters. These polygons were then expanded by 5 km to define final analysis areas representing zones of multi-species co-occurrence. This ensured that the study captured both urban and adjacent non-urban habitats crucial for species movement.

Species distribution models (SDMs) were developed for each focal species using an “ensemble of small models” (ESM) approach, which performs well with limited occurrence data. Occurrence points were spatially thinned to a minimum spacing of 1 km to prevent overrepresentation of dense populations, with a target of at least 20 records per species. In cases of limited data, such as the American Bumble Bee, surrogate models were used (the Black and Gold Bumble Bee model).

Road networks were not included in the SDMs directly to avoid false habitat associations, but they were incorporated into resistance surfaces used for connectivity modeling. Roads were buffered by 30 m and assigned species-specific cost values to represent movement resistance: 1000 for reptiles (reflecting high road mortality), 500 for birds and bats (behavioral avoidance), and 250 for bees (potential roadside habitat but increased mortality risk). These road-cost rasters were then merged with each species’ SDM-based resistance surface.

Connectivity was evaluated using multiple tools. Circuitscape was applied to identify likely movement corridors and high-current areas representing multi-directional pathways, while Graphab was used to analyze habitat patch importance and network structure through the dPCk metric. Fragstats provided quantitative measures of landscape configuration, including connectance and clumpiness. Together, these tools revealed both broad and fine-scale patterns of connectivity and potential barriers for each species within and around the urban zones.

Results

Findings showed that many species retain moderate to high habitat proportions within urban landscapes, but the strongest connectivity corridors are typically located outside urban boundaries. Riparian and wetland zones were identified as critical linkages, especially for aquatic and semi-aquatic species such as turtles and snakes. Among the cities, Kalamazoo and Detroit North exhibited the most extensive multi-species connectivity networks, while Benton Harbor and Detroit Southwest showed more limited urban movement potential. Turtles had the highest habitat availability overall, suggesting persistent wetland and forest-edge habitats, whereas grassland species like Henslow’s Sparrow and bumble bees had the least. The study also emphasized that smaller, well-placed habitat patches often contribute more to overall connectivity than larger, isolated ones.

Fig. 3. Map of study area (a) showing Least Cost Paths (LCP’s), (From left to right) Protected areas, barriers impeding connectivity, and current species density.

Critiques & Reflection

This study effectively demonstrates how integrating multiple connectivity modeling tools can inform urban conservation planning. The inclusion of diverse taxa from reptiles to insects gives the findings broad ecological relevance. I found it particularly valuable how the authors linked quantitative spatial analysis to practical conservation implications, such as protecting riparian corridors and small but strategically located habitat patches.

The article does a great job of emphasizing the importance of riparian corridors and buffers, which in my opinion are not adequately regulated under today’s environmental laws. These areas are critical for maintaining ecological connectivity in urban regions, yet they are often overlooked in planning and development regulations.

Although the paper briefly mentions genetics, I believe this is an area that deserves greater focus. Genetic diversity and gene flow are essential components of wildlife corridor restoration, especially for populations that have become isolated by urbanization and experienced bottlenecking. Wildlife corridors are not only about providing safe passage between fragmented habitats,  they also serve as vital habitat themselves, supporting long-term survival, breeding, and dispersal. Many isolated reptile populations, for instance, have not experienced genetic connectivity for centuries due to habitat fragmentation. Snakes are particularly vulnerable to urbanization and the lack of corridors, as they are frequently forced to cross roads where they face high mortality rates, often being killed by vehicles, sometimes even intentionally, despite their protected status.

Despite these challenges, the approach presented in this study offers a replicable framework for urban planners seeking to incorporate biodiversity goals into development strategies. It highlights that even within heavily modified landscapes, thoughtful urban design and targeted protection efforts can sustain rare species populations and maintain ecological connectivity.

Reference

McCluskey, E. M., Kuzma, F. C., Enander, H. D., Cole-Wick, A., Coury, M., Cuthrell, D. L., Johnson, C., Kelso, M., Lee, Y. M., Methner, D., Rowe, L., Swinehart, A., & Moore, J. A. (2024). Assessing habitat connectivity of rare species to inform urban conservation planning. Ecology and Evolution, 14(3), e11105. https://doi.org/10.1002/ece3.11105

Desert Cities and Bird Loss

Posted on by Jane Herrera

A study conducted in the urban desert environment of Phoenix, Arizona, examined the impact of climate change on bird biodiversity. Researchers found that there was a connection between impervious surfaces and rising land temperatures and declines in bird abundance and species richness, specifically during the winter. This study uses extensive long term data from 2001-2016 to gain information on the topic and while a lot was gain from extensive data there does not seem to be concrete solutions yet, for urban planning. The study shows a functional group analysis that shows different bird roles like pollinators, insectivores and other responds differently to environment changes with different ecosystem services. Although, temperature and urban development cause a decline in bird diversity, impacts can be very different. This means there cant be one strategy, but multiple for each specific group, in order to conserve. One key solution suggested was “enhancing vegetation”, a model showed that increased vegetation were associated with higher bird numbers. Planting native trees or shrubs may help reduce the negative effects of impervious surfaces and rising temperatures in urban location. Enhancing and managing urban vegetation are just a few strategies that can help to support wildlife and maintain essential ecosystem services.

https://esajournals-onlinelibrary-wiley-com.prox.lib.ncsu.edu/doi/epdf/10.1002/eap.70063

A Review of Dupuis-Desormeaux et al.’s (2022) “Re-evaluating invasive species in degraded ecosystems: a case study of red-eared slider turtles as partial ecological analogs”

Posted on by Emy Tran

In this article, Dupuis-Desormeaux et al. (2022) discuss the manner in which introduced species are frequently labeled as “bad,” without first considering their potential to promote the ecological functions of degraded ecosystems. This paper is extremely significant in the world of conservation work, as it asks its audience to completely reevaluate what an invasive species means for an ecosystem, and for most conservation biologists, that would mean considering an invasive species as beneficial. The species that Dupuis-Desormeaux et al. (2022) ask their audience to reconsider is the red-eared slider (Trachemys scripta elegans), but the idea presented by this paper goes much further than just the red-eared slider. The paper suggests that under certain circumstances, some invasive species may be beneficial to an ecosystem, or at least contribute to some ecosystem function. This idea is relatively foreign to most, as we are taught on a large scale that invasive species are damaging to ecosystems. This paper introduces that invasive species may not just be bad for ecosystems, and that they could even be used methodologically to repair damaged ecosystems. 

Dupuis-Desormeaux et al. (2022) ask audiences to completely reevaluate how they view the red-eared slider, considering beyond the many threats that they pose, and instead assessing how they may perform as “contributors to ecosystem functions in degraded” habitat. Turtle species globally provide paramount ecosystem functions. This article classifies these functions into six categories: biomass contributions, energy flow and scavenging value, mineral cycling and bioaccumulation, trophic status, seed dispersal and germination enhancement, and bioturbation in soil dynamics. Like most turtle species, red-eared sliders perform all six of these ecosystem services; however, as Dupuis-Desormeaux et al. (2022) highlight, this species is deemed extremely undesirable, even in habitats where native turtles have been eradicated and are no longer able to perform such services. It is important to note that this article does not advocate for the further release of red-eared sliders into wild and natural spaces; however, it offers that in the current ecosystem of turtle populations declining precipitously as a result of increased anthropogenic pressures, especially overutilization and habitat destruction, red bearded slides, being the prolific species that it is, may be able to provide ecosystem restoration services in habitats that have become to degraded for native species to occupy. 

While reading this paper, I began to question whether red-eared sliders have been studied sufficiently to warrant their classification as an invasive species. In several sections discussing the ecological effects of red-eared sliders in non-native habitats, the author notes that many of the proposed impacts remain inconclusive due to a lack of comprehensive research. This raises an important question: what criteria must be met for a species to be officially designated as “invasive”? If, as the author hints, the red-eared slider has never been proven to have all of the suggested negative impacts on ecosystems, what is distinguishing the turtle as an invasive species rather than an introduced species? However, this species has been proven and is largely known as a prolific invasive species. Given the red-eared slider’s listing as one of the top 100 worst invasive species by the IUCN due to its significant global ecological impacts, allowing populations to remain unchecked poses a legitimate risk of rapid and uncontrolled population growth.

The author suggests that in some cases, it may be beneficial to allow red-eared sliders to remain in their non-native environments, as they may be filling vacant ecological niches. While this idea may seem reasonable in the short term, the paper also highlights that more habitats are becoming suitable for these turtles, potentially allowing their populations to expand further. If their numbers continue to increase, it is plausible that they may enter ecosystems where they could have detrimental effects. Additionally, if red-eared sliders are allowed to persist in non-native areas, there is the possibility of hybridization with native turtle species, such as the yellow-bellied slider. This poses further issues concerning the significance of said hybridization, and its potential to be used to increase genetic diversity rather than eradicate local existing species. This case is also quite interesting as although hybridization is a natural phenomenon, the global span of this species could have broader implications, contributing to the creation of several hybrid species.

Reference: Dupuis-Desormeaux, M., Lovich, J.E. & Whitfield Gibbons, J. Re-evaluating invasive species in degraded ecosystems: a case study of red-eared slider turtles as partial ecological analogs. Discov Sustain 3, 15 (2022). https://doi.org/10.1007/s43621-022-00083-w