It’s time to consider how we can have more animals in our daily lives in the city.
BY PAMELA YEH & IAN MACGREGOR-FORS
The shelter-in-place orders and the massive drop in human activity in our cities, designed to slow the spread of COVID-19, have given us surprising and unexpected sightings of wildlife species across cities around the world. But beyond general awe—and a brief respite from the gloominess of the news—what can seeing all of this wildlife tell us about human-deprived spaces?
Although the media has mainly covered unexpected sightings occurring in urban settings as a result of lockdowns, there are other important, more subtle changes that are happening in the world. First, some species, including those currently living in cities and those making the occasional forays into them, are now able to use habitats and resources that they had never before been able to exploit. Second, species in cities are experiencing a less harassing environment—less active, less noisy. An unknown number of adjustments have been taking place within a short window of time, and thus we are experiencing a once-in-a-lifetime opportunity to study how humans affect other animals in our cities. Although many of us had assumed that some of these individuals avoided cities mainly due to changes in habitats, it is clear now that we humans scare many of them out.
Fear in wildlife has been broadly addressed, and we know that a lack of fear can occur in the wild. Some of the most common examples come from the Galapagos Islands, where many of the animals on the archipelago (particularly as adults) have no natural predators. For example, adult Galapagos tortoises are fearless because they have evolved in an environment with no predators. Indeed, some research has shown that insular systems have tamer animals. Lizards from islands flee from human approach at closer distances than those from mainland habitats, a pattern that has been shown to override phylogenetic closeness.1 Although studies are often correlational, evidence points to the lack of insular predators as one of the main causes behind this intriguing pattern. Yet, things are not very straightforward when we add humans to the formula. Empirical findings have shown that there is substantial variation in inland species’ and populations’ responses to human presence. A behavioral study focused on six different Galapagos species has shown that some of them do respond with fear to human tourist activities, but some do not. Furthermore, species such as the small ground finch (Geospiza fuliginosa) still show fear responses to introduced predators years after predators have been exterminated from the island, suggesting that evolutionary changes, and not just phenotypic plasticity related to wildlife behavioral responses, can occur in a relatively short time frame.2
Some species in cities are experiencing a less harassing environment—less active, less noisy.
So where does this leave us in terms of understanding responses of animals to rapid increases and decreases in human presence? There are few clear patterns, and even fewer clear results, regarding some key ecological and evolutionary questions: Are the changes we see evolutionary in nature, or due just to phenotypic plasticity? How does the environment an individual is born into reflect future behavior, ecology, and fitness? Do populations adapt as quickly to the sudden absence of humans as they do to their sudden presence?
In the relatively short time period of the lockdowns, animals could make adjustments that range from the expected relaxation of alarm systems, from a behavioral approach, to changes at the evolutionary level.3 In Southern California, we have been conducting a long-term study of several populations of an urban songbird, the dark-eyed junco (Junco hyemalis). Since this woodland species began to move down from the mountains into the cities of Southern California a few decades ago, these birds have adapted remarkably well to the sunny coastal lifestyle.4 Their population numbers are rising, and they have begun to move from college campuses to both dense city centers and leafy residential suburbs. Not surprisingly, these birds are not too scared of humans…
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http://nautil.us/issue/85/reopening/welcome-back-animals
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