Environment-Biodiversity-Effects: Difference between revisions
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=====Long-term predator–prey cycles finally achieved in the lab===== | |||
[https://www.nature.com/articles/d41586-019-03603-3 Nature 12-18-2019] | |||
A key question in ecology is what allows species to persist over time — particularly when there are pairs of species in which one is an exploiter and the other its victim. A long-standing theory attempts to answer this question by explaining how relative numbers of predators and their prey can cycle continuously1. First, prey numbers would increase, giving the predator more food. The subsequent increase in predators would lead to a decline in prey. Predator numbers would then decline owing to a lack of food, restarting the cycle. However, it has proved unexpectedly challenging to demonstrate this type of persistent predator–prey cycle in simple controlled systems in the laboratory. Writing in Nature, Blasius et al.2 report just such a demonstration, succeeding where almost 90 years of experimental work has failed. | |||
The challenge posed by such a demonstration was exemplified in 1934 by the ecologist Georgii Gause4, who studied the dynamics of two unicellular organisms — the predator Didinium nasutum and its prey, Paramecium caudatum. Gause found that, on the one hand, if the predator was efficient, it ate up all the prey and then starved. On the other hand, if part of the environment helped to conceal the prey, the predator was less efficient — and so starved (Fig. 1a). Coexistence and long-term cycles could be achieved only through artificial means — namely, by adding prey at regular intervals. | |||
=====Light pollution is key 'bringer of insect apocalypse'===== | =====Light pollution is key 'bringer of insect apocalypse'===== | ||
[https://www.theguardian.com/environment/2019/nov/22/light-pollution-insect-apocalypse The Guardian 11/22/19] | [https://www.theguardian.com/environment/2019/nov/22/light-pollution-insect-apocalypse The Guardian 11/22/19] | ||
