https://doi.org/10.3389/fevo.2020.576665

Growing urbanization has displaced many animals and has led to the rapid adaptation of animals across many taxa. Recently, it has been an area of study to determine what adaptations are taking place in order for species to be more fit for an urbanized environment. This article focuses on the different types of behavioral changes and which animal orders are being observed successfully adapting to urban environments. Among the 83 published papers that were included in this review, there were 44 distinct behaviors and 155 individual occurrences of behavior changes in urban areas. The observations, behaviors, and number of occurrences for each respective behavior change all have the potential to support successful urban wildlife management and conservation. 

Considering the issues with their methods of retrieving relevant peer-reviewed publications, the authors did not agree upon the definition of “urban” for their search engine. This led to a broad overview of papers that were not consistent with their determined levels of urbanization. Also, they excluded any articles that were not in English or reliably translated. Although this is purposeful in order to not misinterpret results/findings from the paper, this may also mean that there is a large body of literature that is not considered, which also limits the geographic scope of the literature review. This is demonstrated by the fact that 52% of their data was from North America, followed by 20.5% from Europe. Additionally, the authors did not include any papers that are inaccessible via university resources or general internet access. This makes it easy for readers/researchers to locate the literature cited and find the primary research, but the authors could have included a section encompassing data they accessed via communication with the primary research authors to expand the data set that they analyzed.

The results showed that the most abundant behavior type studied was the alert response, followed closely by spatial change. Alert response was seen as changes in vigilance/caution behavior and was shown to both increase and decrease in urban areas. Spatial behavior was commonly shown as a decreased home range. Other common trends were increased nocturnality, a shift in resource selection, increased boldness, and increased exploratory behavior. Behaviors were sorted by animal order and then within each order broken up by guild (carnivore, herbivore, omnivore). The results of this study could have included a snippet about broad behaviors like shifting resource selections to give the readers insight as to why an animal would be altering its food source (Was the shift in resources due to abundance? Nutrition levels?)

Although there is a clear indication that species are responding behaviorally to the urban environments, the authors suggest that there are underlying mechanisms like region/ resource availability that act as external factors to further effect the adaptive behavioral response. Future research can be improved by being more inclusive of mammalian species, herbivores (especially deer/raccoons), and being aware that behavior is multi-directional/fluctuating. Ultimately, this research can be insightful for city planners, wildlife managers, and urban residents since human-wildlife interactions may be resulting from these potentially predictable behavioral changes.

Ritzel, K., & Gallo, T. (2020). Behavior change in urban mammals: a systematic review. Frontiers in Ecology and Evolution, 8, 576665.

https://doi.org/10.2193/2008-512

As the range of coyotes (Canis latrans) in northeastern regions of the United States increases, human-coyote interactions (HCI) have become a more prevalent issue in suburban and urban areas. The authors of this article focused their research of HCI in Westchester County, New York, distributing 6,000 surveys to students kindergarten to 12th grade. Each survey asked if the family members had seen or heard a coyote within the past 3 years: how many, at what time of day, and at what time of year? The students address was attached to these answers in order to geographically place them as data points. The sightings data was also compared to a rural-urban gradient based on the intensity of development (density of infrastructure/buildings). 

When considering the methodology of their sampling, it is important to consider that they employed a voluntary response method. Although the authors mentioned that over 1,500 responses from the households of the students gave a spectrum of land use types (rural, suburban, urban), this variability could have been accounted for better if they had used the documented reports of HCI from local police departments as their sampling frame and then chose their sample size from simple random sampling within each source of reports (stratified sampling). This would have decreased the possibility of response bias since there might be a confounding variable to consider when assessing who had taken the time to fill out the survey (perhaps those who had encountered a coyote more frequently were more likely to share their story than others).

The data was found to show the following trends: visual sightings increased closer to nighttime, most sightings were of solitary coyotes across seasons, encounters were most likely to be closer to forest and grassland land cover types and farther from medium to high intensity development. The collective findings were then used in conjunction with previous coyote sightings data to formulate a map of Westchester County, NY depicting the probability of coyote observation.

Having a map with the probability of human-coyote interactions can lead to more focused management techniques. Areas which are at high risk for encounters could have more educational outreach from local government agencies to minimize attracting coyotes (practices such as keeping pet food and garbage secure). Also, these areas could benefit from greater awareness of the presence of coyotes so that preventative measures and active engagement in environmental issues from residents could lead to a proactive mindset and willingness to share their space with a predator species. This article is also significant in the way that it highlights the use of citizen science to quantify human-wildlife interactions. Making use of residential viewpoints and modern technology can gather data at a more efficient rate than experimental study sites. This connection between citizen science and human-wildlife interactions in an urban setting can be seen in many other papers (https://doi.org/10.1071/WR10007 = citizen science and tagged urban wildlife, HTML  = citizen science and Tuscon Bird Count, https://doi.org/10.1371/journal.pone.0156425 = citizen science and birds/ butterflies.

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Insects, being one of the most diversified and important ecological groups on the planet, are at risk of declining populations due to climate change. This paper focused on how using data from long-term monitoring of insect populations could give insight and answer more recent questions regarding population dynamics and climate change. The authors pooled together various studies that had at least a 10 year continuous sampling time frame, looked at 10 or more species, was restricted to a “protected area/ gradient of land use,” and analyzed climate change as a possible causative factor.

A case study highlighting butterflies residing in an “undisturbed” mountainous portion of northern California was used to explore any relationship between geographical differences and climate change. It was found that montane insects had easy access to a range of elevation gradients and therefore could adapt to changing climate by moving to more optimal thermal environments in order to efficiently thermoregulate. Since insects are poikilotherms, they must rely on the environment to regulate their body temperature, unlike those that have an internal temperature regulation. Having microclimates closer in proximity to one another without fragmentation by human development meant the insects could easily disperse amongst the patches of optimal habitat in order to fulfill their thermal needs.

An aspect of this analysis that differentiates it from papers that simply want to confirm whether or not climate change is directly influencing insect population dynamics is comparing climate change to other stressors like land use. From a management perspective, this would allow resources and time to be effectively allocated to mitigate whichever stressor is likely to have the greatest impact. Although this is a logical way of attempting to maximize the potential to conserve a population and its ecological niche, the stressors are not always so clear-cut and many times are entwined or even interdependent on one another. Stressors that might have been initiated by climate change have been shaped or accelerated by anthropogenic influence.

The selection of studies chosen to be analyzed through the aforementioned criteria also include an inherent geographical and taxa bias, since the majority of long-term continuous insect observations have been based in northern Europe and looked at the order Lepidoptera (butterflies and moths). The gap in long-term studies has hindered understanding of climate change over a diverse range of biomes, especially those found in tropical areas where there is an insect biodiversity hotspot. Conclusions being drawn from collective studies mostly pertaining to Lepidopterans cannot be applied to the full class of Insecta, as the dispersal rate to new microclimates for butterflies is a feat that may not be as easily accomplished by Coleopterans (beetles) for example.

This article is important because insects can be keystone species or even ecosystem engineers and without them a vital portion of the food web would be missing. In order to effectively mitigate stressors for insect populations, there must be more inclusive long-term studies that give insight on a more diverse spectrum of insect orders and geographical range. Additionally, this spreads awareness to the importance of a continuous landscape with a gradient of microclimates for insects to disperse to suitable thermal environments in response to climate change.