Our Own Ecosystem

With spring coming (although it may not seem that way in the northern states of the USA), it’s worthwhile to consider again how we might manage our lawns and yards in an ecological way. Combined below are tips from The Nature Conservancy and other sources that enlighten us on how to manage our yards and lawns a little more ecologically. Most suggestions are not new but collectively point us toward seeing our small piece of the Earth differently than the golf course ideal that requires continuing heavy chemical subsidizing to achieve.

  1. Increase wildlife value of your lawn by mowing less often and minimize use of pesticides and fertilizer. Allow clippings to remain on the lawn where their presence supports small decomposer creatures thus sustaining or regaining mechanisms that return nutrients to the soil and build up soil organic matter. If you’re cutting close to the ground, raise the mower cutting height to a higher level.
  2. Keep your pets indoors as much as possible. Keep dogs on lease and cats confined. Remember that wandering pets hunt and kill wildlife in great numbers even when well fed. See “Naughty Tabby” on this website. TNC notes that keeping cats indoors extends the life span of house cats by about a decade. This occurs as cats are protected from vehicle traffic, unleashed dogs and diseases caused by bacteria, viruses, worms, ticks and fleas.
  3. Protect birds from collisions with windows by applying striping, artwork or other treatment to reduce extensive areas of sheer glass. Of course, divided panels already help reduce the area of continuous glass.
  4. Keep outdoor lights to a minimum particularly if they penetrate the night sky or direct beams horizontally. Migratory birds orient towards lights as they fly, leading to fatal collisions. It’s sad to contemplate that many thousands of migratory warblers, thrushes, vireos and other migrants have been killed by ceilometers each year. Even residential lighting can be harmful. Bright bluish light is the most harmful and soft yellow lighting the least. As an example of the carnage from lights, at one north Florida TV tower, 8,123 birds were killed by collisions in five autumn periods (Crawford 1981).
  5. If you elect to entice birds to visit your yard by feeding, provide seedeaters with healthful seed- particularly black oil sunflower and proso millet seed. Please no bread or cooked grains! Suet (beef fat), which is eagerly eaten by jays, woodpeckers, nuthatches, etc., should not be allowed to become rancid which occurs rapidly in temperatures above freezing. The Cornell Univ. Ornith. Lab points out that melted suet can coat belly feathers of incubating birds causing pores on eggshells to become clogged, interfering with gaseous exchange.

 Water is important. To keep birds around, make sure the water is kept ice-free (admittedly much easier in Florida than in Maine!). Remember that cutting off food and water provisions mid-winter can cause potentially harmful food and water scarcity when most needed.

  1. Bird species that rely on natural wood cavities for nesting face a dearth of potential sites in suburbia where dead or dying limbs are often quickly removed. Depending on the size of the yard and the location of trees within it, it may be possible to avoid cutting dead limbs or declining trees given that they are potential nesting and feeding resources for hole-nesters.
  2. The chemicals sold as pesticides readily kill insects regardless of their function in the residential landscape. We may, as a result of pesticide application, have fewer plants exhibiting herbivore damage (like holes in leaves, missing leaves or discolored ones) but we also are likely to see fewer butterflies, pollinators and predatory insects that help limit pest populations. Swallows, nighthawks and many other insectivorous birds will also be stressed by reduced food availability and many of their populations have declined.

As an alternative to insecticides, consider, at least in some areas,  Heterorhabditis, a genus of nematode worm  that consists of 14 species all of which are obligate parasites of insects. As such they are used to control pests such as root weevils which damage lawn grasses and other cultivated plants. They are widely sold on-line and at garden shops and claim to work on hundreds of insect pests. The ecological benefit of course is that the worms replace pesticides and produce no harmful residues or run-off.

Take a walk one summer day in the woods or fields and focus on leaf condition. This will vary, but note that many if not most plants will have less than perfect leaves. Perhaps realizing this will allow us to accept a certain level of herbivory in our yards, particularly if we see it as a byproduct of reducing chemical treatments. Severe outbreaks such as from Japanese beetles, tussock moths or gypsy moths will, of course, present a strong challenge that leads most of us to resort to insecticides.  Did you know, however, that some pests such as tent caterpillars can defoliate cherry trees, leaving quite a mess, but that the trees ordinarily recover?

  1. Even in a small yard habitat diversity can be promoted. Areas or patches of lawn can be given over partially or entirely to native flowering plants (forbs). These can be established in dense plantings or scattered across a larger area. Many forbs are compatible with lawn grasses and provide color or textural variation that is an alternative to uniformity plus they attract harmless insects to the yard. The photos (at bottom) show three native forb species that colonized the yard spontaneously and were left alone. Each of these can be left to flower and then mowed or not. In either case they are perennial denizens of this Florida yard. Note that these species, admittedly common,  are regarded in many quarters as weeds deserving only of chemical extermination!

Areas under trees are better for growing ferns or other shade tolerant species than lawn grasses which thrive mostly in full sun. Another benefit is that the shady areas do not need mowing.

Instead of viewing self-established species in lawns as invaders to be killed off, think of them as colonizers and watch them over a period of months or years. Roadsides, verges and boundaries can be planted with perennial grasses, low shrubs or flowering perennials that require little care including little or no irrigation and fertilizer.

  1. Interested in aquatic habitats? A hole lined with thick plastic sheeting can serve as a “mini-pond” in the yard, preferably where there is at least some sun. I’ ve had success with a  hole no more than two feet (60 cm) at its deepest and just over 6 feet (2m) long and 3.3 ft (2m) wide. It is lined with a few native marsh plants brought in which have spread naturally.  The pond is deep enough to support water lilies (in containers) and a surprising variety of animal species- a thriving Gambusia (mosquito fish) colony, leopard frogs, green tree frogs (periodically), dragonfly and damselfly larvae, whirligig beetles and aquatic spiders. 
  2. As an alternative to herbicides, consider corn gluten meal, a non-toxic protein produced as a powdered byproduct of corn milling. Its main use has long been for hog feed but it is increasingly recognized for its effectiveness as a weed suppressor and lawn fertilizer (the meal consists of 10% nitrogen). It is especially valued as a pre-emergent herbicide which is added to soil to inhibit germination of weed seeds including such notorious invaders as crabgrass. The cost of the meal will somewhat exceed that of chemical herbicides but consider the ecological benefit when deciding whether to use it. At this stage of market development, corn gluten meal is available mainly from internet providers rather than local garden shops (see http://www.gluten.iastate.edu).
  3. If you must apply lawn fertilizer, make these environmentally-sound choices:
  • Avoid fast-release chemical fertilizers (pollutes soils and waterways)
  • Avoid animal-based products like bone meal and fish-meal (bad for dogs!)
  • Don’t mix starter fertilizer with herbicides (seeds won’t germinate!)
  • Follow application instructions. Don’t over-fertilize (more is not better)
  • Use slow-release (or organic) fertilizers for long-term benefit
  • Apply high-nitrogen fertilizer in spring but not late in the growing season
  • Apply fertilizer no more than twice a year
  • Take special care to avoid releasing fertilizer onto non-absorbent surfaces like roads, paths and walkways (these convey fertilizer chemicals quickly to waterways).
  • Limit lawn watering to 1” (2.5 cm) weekly. Estimate this by placing an empty can in lawn and watching the water level. Water before the sun is up.
  • Don’t panic in a drought. Most lawn grasses are drought-tolerant and can go a month without water, longer in fall and winter. Remember that browning of grass is really an adaptation to dry season conditions. Greening and new growth will occur when rains return.

Crawford, R. L. 1981.  Weather, Migration and Autumn Bird Kills at a North Florida TV Tower. Wilson Bulletin 93:189-195.

Part of aback-yard lawn completely converted to flowering shrubs that attract birds.

Part of a back-yard lawn  converted to flowering shrubs that attract birds in all four seasons. Total area is about an eighth of an acre (ca 500 square meters). Adjacent yards contribute additional habitat.

Stachys floridana has pink or white flowers and  edible white tubers but competes successfully with lawn grasses.

Stachys floridana  of the mint family has pink or white flowers and edible white tubers but competes successfully with lawn grasses and is disparaged by many.

Erigeron quercifolius, biennial or short-lived perennial spreads slowly in yards.

Erigeron quercifolius, biennial or short-lived perennial spreads slowly in yards. Rosettes stay below mower blade heights.

The tiny,native Dichondra  carolinensis invades moist lawns in the southern US, staying below blade heights.

The tiny, native Dichondra
carolinensis invades moist lawns in the southern US, staying below blade heights.

 

 

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