My last post was a celebration of the rich native
biodiversity found in the forests of southern Ohio which we experienced at the
third annual Mothapalooza event. Our two keynote speakers, David Wagner and
Doug Tallamy, were great fun to be with but their messages were sobering. So
this post won't have many pretty pictures because, quite frankly, the big
picture isn't pretty at all.
We are losing native species of plants and animals at an
alarming rate. In his book Bringing Nature Home, Tallamy cites studies that
show that we have lost an average of 1% of our native migratory birds annually
since 1966. That is nearly a 50% reduction in the population of many of our
bird species in the past 50 years.
The drastic decline of monarch butterflies in recent
years has gotten a lot of attention, but other insects have fared just as
badly. Why do we need to care? We need to care for many reasons and here are a
few.
The decline of native insects is directly related to
habitat loss, which is basically the loss of the plant communities upon which
they depend. Native insects have evolved along with native plants, and many can
only survive on those particular species. When we lose the plants, we lose the
insects.
Human lives are inextricably tied to healthy plant
communities, even though we generally ignore this fact. Plants produce the
oxygen that we breathe. Healthy forests filter the water that we need to
survive. Insects that feed on the plants are necessary to pollinate many of the
food crops that we rely on for survival. Recent studies have even shown that
spending 15 minutes in a natural area lowers stress levels and improves blood pressure
better than drugs or psychotherapy!
Many of you that are reading this blog enjoy feeding
birds in your yard, and spend a fair amount of money on birdseed. But without
insects, birds can't survive. Seeds have lots of carbohydrates and some fats,
but little protein, and protein is necessary for building animal tissue. Baby
birds need protein, which comes to them in mostly in the form of caterpillars
that their parents forage for and bring to them. If they have to go far and
wide to find those insects, the energy cost will be too great and the nest will
likely fail.
Most caterpillars are specialists. In other words, they
need particular plant species upon which to feed. Compatible biochemistry is
necessary, and only is found in those insect and plant species that have
evolved together over time. So filling your yard with gingko, Bradford pear and
other alien species isn't going to do much good, from a biological standpoint.
Not only have we destroyed native habitat in order to
develop our cities and suburbs, we have introduced all sorts of plant and
animal species that have, in many cases, overwhelmed, eaten, and/or crowded out
the native plants and insects that are so essential. Kudzu, Japanese
honeysuckle, and autumn olive are just a few examples, and then
there are the European starlings and house sparrows whose populations have
increased enormously since their introduction. The emerald ash borer, an Asian
species, has destroyed billions of ash trees, which supported many native
insects, and has cost homeowners and municipalities an enormous amount of money.
Recently, we were at a natural area and saw a brown
marmorated stink bug (that alien brown critter that finds its way into our
houses) sucking the life out of a monarch caterpillar.
I could cite many more examples, but at this point readers
may be thinking I get it, so what can we do about it? Unfortunately, parks and
preserves are not adequate to halt the precipitous decline of native species
(and they are struggling with the influx of aliens). Here are some suggestions
from Doug Tallamy and Dave Wagner:
Plant native species in your yard! You don't have to get
rid of all your hostas and daffodils, but include some native trees, shrubs and
perennials in your landscaping. If you have room, plant some big native trees
like oaks, maples, hickories and hackberries. Include both nectar plants for
insects and caterpillar food plants. Doug's book offers lots of suggestions
about plants that are suitable in various regions of the country.
We have
started to convert most of our landscaping to natives, but I still have my
hostas and Endless Summer Hydrangea that I got years ago from a friend. They
are basically biological deserts, but I have a lot of other plants that are
beginning to attract pollinators and other insects. Suburban lots can be essential
for maintaining the native biodiversity that is so important. But walk into any
garden center and you won't see many native bugs because all they are selling
are alien plants that have no value for our native insects. Seek out and support
native plant nurseries in your area.
Preserve habitat! Buy land, especially forests, if you
have the means, and join and actively support organizations that preserve and
rehabilitate natural areas.
Minimize or eliminate the use of lawn chemicals! Dandelions and clover never hurt anyone. Clover is a wonderful nectar
source for all sorts of insects, but is killed by lawn herbicides. Excessive
fertilizer runoff is a real threat to our water supplies.
Vote for people who understand and appreciate good
science! This is a lot more important to our survival as a species than how
they look on TV or what they did in college 30 years ago.
The situation isn't hopeless, but we are getting close to
that point. So at least plant some natives in your yard and encourage your city
to do the same in parks and street rights of way. Neighbors--stop by any time
and walk around our back yard to see how it evolves since we have planted
spicebush, native viburnums, shrub dogwoods, wild hydrangea, cedars and many
others. Look at what's coming up in our rain gardens, which divert runoff from
our downspouts into basins where it can sink into the ground to recharge
groundwater and lower stormwater runoff, a whole other topic that I haven't
mentioned! Here are a few pictures of some of the native plants in our yard:
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| Orange Milkweed and Blue Vervain |
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| Redbud, elderberry, purple coneflower starting to bloom, rattlesnake master, and wild hydrangea. |
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| Closeup of wild hydrangea--these have been great and have attracted all sorts of pollinators |
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| Endless Summer Hydrangea--all flowers are sterile and not much seems to eat the leaves so it really has no biological value. It has sentimental value though, so I'm keeping it! |
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| Purple coneflower |
