New Research by SNPits Blogger Anna on Detecting Rare Species from Predator Scat!
DNA testing to detect rare species from non-invasive samples (e.g. faeces) is becoming more and more common in wildlife management. If DNA results are used to inform management decisions, then it is important to understand the risks and consequences of false positive and false negative results. In this study we set up a blind trial to determine error rates for a PCR and sequencing test used to detect fox DNA from predator scats. This DNA test has been used to screen thousands of scats collected in Tasmania and has identified areas where foxes are, or have been, present. Foxes were relatively recently introduced to this island state and have the potential to become a damaging invasive predator if a population is allowed to establish. If a false positive result were obtained it may lead to an unnecessary eradication response, which could waste resources and damage public opinion (fox management is already controversial in Tasmania). In contrast, a false negative result might allow foxes to further threaten native wildlife. We did not observe a single false positive result from known non-fox scats, meaning that the test has very high specificity. However, as currently implemented the test has a higher risk of false negative results, meaning that some foxes may have gone undetected.
Can apex predators restore ecosystems plagued by invasive species? This paper draws upon trophic cascade theory, often using examples from Australia, to introduce the concept that apex predators might be a better source of control for invasive species than lethal control.
Carnivorous Plant Evolution
Carnivorous plants evolved independently nine times. New fossil evidence places the date of the earliest carnivorous plant at 35-47 million years ago in the genus Roridula which traps insects with sticky tentacles. This short commentary has interesting facts on other carnivorous plants that trap and kill insects but do not digest them, where instead other animals eat the dead insects then defecate and that is the source of nitrogen for the plant.