In Ecology for the Masses, we break down a new scientific article every week, in a format that’s easily digestible for the general public. As I’ve mentioned in our disclaimer, we sometimes talk in absolutes in these articles. However there are always uncertainties in science, and we want to talk about some of them here. For one, to expand a little more on some of the themes that we’ve mentioned, and secondly, as a reminder that science is not dogma, it’s an ever-shifting knowledge base that needs to course-correct and readjust often.
Heuschele and Candolin showed that when eutrophication lowers visibility in a freshwater ecosystem, parasitised, and therefore less healthy males gain more eggs than their healthier counterparts. It’s an important reminder of the indirect effects that changes in ecosystems bring about. However there are a few interesting caveats that are mentioned in the paper’s discussion. Under some circumstances, parasitised males are of higher genetic quality, which could mean that eutrophication could lead to a more viable population. Obviously if this is not the case, the population’s likelihood of extinction increases. There is also the possibility that an increase in numbers could allow the healthier males to outcompete the parasitised males, and even out any potential advantage the parasitised males gain.
The takeaway here was that even the presence of a predator was enough to cause higher mortalities in gestating snowshoe hares. However, Macleod et al.’s experiment occurred in captivity, and there are a number of factors to consider when translating this to the wild. Would higher rates of fear-induced deaths mean that predators end up scavenging more? If so, then effects of the ecology of fear would be negligible. However if they maintain direct predation whilst still producing higher rates of fear-induced mortality, this could significantly effect population levels. It’s especially difficult to obtain data like this in a wild scenario, as you would have to control the regions predators could access, and even then, scent cues may mean that control species not exposed to predators may be able to sense them in the vicinity.
The uncertainties here mainly involve the implications for reef shark conservation. The role on reefs of these shark species is still unclear, and there’s evidence to suggest that reef sharks do not play a role in these ecosystems beyond that of a large fish. Whilst Juhel’s paper suggests that conserving remote areas would be more beneficial to shark populations, but would shifting protection for reefs further away from shore adversely affect the reef community in areas closer to human activity? Whilst apparently ineffective for sharks, some of the areas protected closer to shore could provide conservation benefits for other species.
Science may be viewed as cold, hard fact by some, but there’s always an element of uncertainty, which is important to remember. I encourage you to read the full breakdowns of each study.