I have just finished reading the book, Life in the Soil – A Guide for Naturalists and Gardeners, by James B. Nardi, 2007, The University of Chicago Press. This book provided a fun way to learn about a topic that many people may initially think is boring. Not so! I learned not only about how soil is formed, but about a dizzying array of creatures that live in the soil. The book starts with the beginnings of soil formation, plants and their roots, as well as cooperative bacteria and fungi. The partnerships between plant roots, bacteria and fungi take mineral and organic molecules and start converting them into substances that larger organisms can use. Each organism contributes to and draws from the soil in its own unique way. They interact with one another as well – sometimes symbiotically, sometimes as predator, and sometimes as prey.
There is an excellent page in the book that defines the classifications of organisms in the food web. This is from the section “How to Use This Book,” on page xvi:
Place in the Food Web
The food web is a network of organisms within which energy and nutrients-the substances that all organisms in every [taxonomic] kingdom need for survival-are exchanged. Ultimately each organism dies and returns to the soil; but during its life, it plays one or more of the following roles in the food web:
- Algal eaters – organisms that eat algae.
- Bacterial partners of plants – bacteria that live within plant roots and form a mutually beneficial relationship with plants.
- Coprophages – organisms that feed on droppings and dung.
- Decomposers – organisms that break down the remains or waste products of other organisms.
- Detritivores – organisms that feed on dead plant and animal matter.
- Diggers – organisms that facilitate the circulation of nutrients between layers of soil and help stimulate growth of plants.
- Fungal partners of plants – fungi that form mutually beneficial relationships with plant roots.
- Fungivores – organisms that feed on fungi.
- Herbivores – organisms that feed on plants.
- Parasites – organisms that live in or on other living organisms (hosts) and obtain nutrients from their hosts, usually without killing them.
- Predators – organisms that obtain nutrients from other living organisms (prey) but do not live in or on their prey.
- Producers – organisms that produce their own nutrients from only air, water, minerals, and energy.
- Scavengers – organisms that feed on dead plant or animal matter.
Much of the book involves what most people would call “bugs.” I have gained tremendous respect for bugs now that I better understand the roles that they play in ecosystems. That said, I recommend that you do NOT eat while reading! I’ve had to suppress a gag reflex more than a few times while reading over lunch or dinner!
While sitting in one of my gardens the other day, I glanced down to the ground beside my chair and saw a wasp. It had a very tiny body, and I later looked it up in Life in the Soil, and learned that it was a Thread-waisted Wasp (genus=Ammophila). It caught my attention because it was busily excavating a hole in the ground right next to my chair. About one inch away lay a very still, green caterpillar. The wasp had been going into the hole, head first, and coming out with soil which it dropped to the side. Then it BACKED into the hole a time or two…and then grabbed the caterpillar and pulled it right down out of sight. It happened really fast, and I wouldn’t have believed it would fit and go down so smoothly if I had not seen it with my own eyes. I sat transfixed, watching the wasp immediately start to seal the hole. She actually picked up pieces of grass that were in the way and flew off maybe six inches to drop them and return to continue packing the hole with more suitable bits of pebbles. She braced herself over the hole and dug like crazy with her front pair of legs, dumping sand into the hole as fast as she could. As the hole was nearly full, I even HEARD her tamping the soil plug. She would grab a small piece of decomposed granite and press it into the hole and I could actually hear a buzzing that could only be some sort of packing down the dirt. Amazing! THEN, she proceeded to camouflage the hole by picking up large pebbles and piling them on and around the burrow. She even plucked up the very pieces of grass that she didn’t want for sealing the hole, to place back over the entrance to her burrow to help conceal the entrance.
This thread-waisted wasp was a great example of the very things I had been reading about.
The book goes through the bugs and all the way through mammals. It could be used as a reference, but also is highly readable straight-through. A human-being wrote the book and his sense of humor and love of the subject shows, making it an enjoyable read.
If you like to spend time in your garden, like to get your hands dirty, or just have a craving for knowledge about nature, you’ll want to read this book!