For the southern US / Mexico, even precipitation and upper soil levels exhibit predictive skill of up to 2 — 3 years (Fig. 8d). (link.springer.com)
The decrease in juvenile earthworms in the conventional plots can be explained by the fact that upper soil layers are their preferred habitat. (fao.org)
Bay muds often have a high organic content, consisting of decayed organisms at lower depths, but may also contain living creatures when they occur at the upper soil layer and become exposed by low tides; then, they are called mudflats, an important ecological zone for shorebirds and many types of marine organisms. (sciencedaily.com)