Saturday, July 17, 2010

Pocket Gophers

The tops of the fruit trees are not the only parts of the trees that are in cages. I have to plant the trees in wire cages to keep the gopher from eating the roots of young trees down to a nub. By the time the root system is large enough to outgrow the cage, the tree is usually big and strong enough to withstand gopher nibbling.

Some people use traps or poison to kill gophers. For various reasons, I don't want to use poison, and traps seem pointless. If you kill one, another will move in. I find it's best to incorporate gophers into the landscape. Let them aerate and fertilize the soil, and prune the roots; keep them out of places where I really don't want them, such as around the roots of young trees and shrubs.

I found a dead one in the orchard today. It's too far decomposed for me to guess how it died. You can see from the photo that it was a cute, furry little thing with delicate hind feet like a rat, but it has large front feet with huge claws. Edward Scissorhands.

Most gopher discussions I've found online focus on killing by one means or another, without even trying to understand how gophers fit into the life cycle of the land as a whole. I found a couple of articles whose authors seek a more elegant and intelligent way of living with gophers.

Ecological Benefits of Pocket Gophers (from Living With Wildlife - Washington Department of Fish and Wildlife)

A typical pocket gopher can move approximately a ton of soil to the surface each year. This enormous achievement reflects the gopher’s important ecological function.
Their tunnels are built and extended, then gradually fill up with soil as they are abandoned. The old nests, toilets, and partially filled pantries are buried well below the surface where the buried vegetation and droppings become deep fertilization. The soil thus becomes mellow and porous after being penetrated with burrows. Soil that has been compacted by trampling, grazing, and machinery is particularly benefited by the tunneling process.
In mountainous areas, snowmelt and rainfall are temporarily held in gopher burrows instead of running over the surface, where they are likely to cause soil erosion.  [my note: even in non-mountainous areas, gopher burrows help to hold water in the soil and prevent water run-off]
Surface mounds created by gophers also bury vegetation deeper and deeper, increasing soil quality over time. In addition, fresh soil in the mounds provides a fresh seedbed for new plants, which may help to increase the variety of plants on a site.
Many mammals, large birds, and snakes eat gophers and depend on their activities to create suitable living conditions. Salamanders, toads, and other creatures seeking cool, moist conditions take refuge in unoccupied gopher burrows.[my note: I have found a couple of toads lately living in abandoned gopher burrows]  Lizards use abandoned gopher burrows for quick escape cover.

Gabriel J. Miller, Steve A. Johnson, and Lora L. Smith, University of Florida, have published an article titled Ecological Engineers: Southeastern Pocket Gophers Are One of Natures Architects 
The authors discuss the soil mixing benefits of gophers then move on to discuss the effects of the gophers' diet:

Root Herbivory  By feeding on plant roots, Pocket Gophers can drastically affect the local plant community. Some plants can tolerate root herbivory and even flourish, but others are adversely affected. For example, grasses are known for responding favorably to root herbivory, which may be why gophers and grasses coexist together. Little is known about the effects of root herbivory on most plants, but it is likely that the root herbivory of gophers influences plant communities.

It's disheartening to realize that the only advice being given to farmers and gardeners by government supported agricultural extension services, and agricultural universities is grounded in ignorance.  It's true that most people who grow plants in regions where gophers live are very well aware of the effects of gophers on specific plants in the garden. But most people farm and garden in ways that make their plants vulnerable, instead of establishing communities of plants and animals that support and protect each other. I'm close to 100% sure that some things I did with my fruit trees made them attractive to the grasshoppers. I'll write more about that later.  

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