The environment is changing and the planet’s wildlife is reacting. But to what degree can that be measured and better understood?


In a human dominated world, earth’s environment and ecosystems are afflicted, directly impacting wildlife. Monitoring ecological responses of species at the physiological level to understand the impact of these developments on wildlife populations could be key to developing future management and conservation efforts to address these changes.

Stephen McCormick of the US Geological Survey and Michael Romero of Tufts University describe the emerging field of conservation endocrinology and its growing role in addressing the effects of environmental change.

The endocrine system is a system of glands that release hormones–essentially, chemical messengers–into the circulatory system to regulate the body and bring about a physiological response to relevant environmental changes.

Developments in endocrinology field techniques allow researchers to determine an animal’s hormonal status while it ranges uninhibited in the wild, providing perhaps the most fundamental measures of an animal’s success and survival.

“After all, it is hormones that largely control reproduction and coordinate the physiological responses necessary for survival in a stressful environment. Thus, endocrinology offers us a window to better understand the factors impairing a species’ demographic vitality, and it may even offer us early-warning signals of a risk before survivorship or reproductive rates plummet.”

Conservation Endocrinology: Field Endocrinology Meets Conservation Biology

Gathering data on endocrine system responses of wildlife to environmental factors can provide early warning of how populations will respond to environmental changes. With this information, managers can better understand the impacts on animal welfare and reproduction, paving the way for effective contributions to biological conservation methods and decisions.

One hormone in particular is of great interest, the stress hormone cortisol, in response to potential stressors. Stressors can include human encroachment, urbanization, hunting, invasive species, habitat disruption and ambient noise. Cortisol levels rise when the animal experiences short or long term environmental stressors, providing a physiological signal causing the body to react accordingly, be it to mobilize to another area or alter reproduction, delaying or stopping for the season if necessary.

Advances in technology has allowed for measurement of cortisol and other hormones in more than just blood tissue. Feather, scales, urine, feces, saliva and hair samples can convey information about the individual’s physiological response to environmental stress. Relying solely on blood collection to determine endocrine responses is self defeating, such that obtaining blood can be a stressor in itself as it requires direct interference with the animal, altering the very cortisol levels that researchers are trying to measure. To be able to collect other tissues in a less invasive, non-direct manner allows for easier sampling of wild animals in their natural environment.

In a unique new development drone technology has offered a new method to monitor cetaceans. Dubbed, “Snotbot” a drone is deployed from a nearby watercraft, and can be aerially positioned above a whale as it surfaces to capture a hormonal sample from “whale blow”, which contains respiratory microbes (or snot) that can be obtained easily and non-invasively, revealing hormonal information about the species’ reproductive capacity and broader health and welfare.


Snotbot drone collects whale blow.

Researchers are also looking at animal response to ecotourism. To better understand how wildlife is fundamentally affected by our presence, managers can tell where ecotourism is beneficial and where it is harmful. In one study of wild elephants, cortisol levels were found to only be slight increases of stress in elephants, but not enough to have a negative impact.

But endocrine studies in wildlife are still in the very early stages. While sampling is at the individual level, there needs to be many more assessments to be able to extrapolate to the population level. As research continues, what is being revealed can be directly applied to our own actions and how that may be affecting animals, says McCormick, “That’s what we have the most control over, our own actions, we could make a large contribution to increasing populations we’ve impacted.”

Future studies are being developed that will look at impacts of human activity, climate change and pollution aspects interacting with endocrine systems. This will help reveal our role in changing animal’s response to environmental cues and how we might change our own behavior to help mollify theirs.

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