HomeMy WebLinkAboutCOM 1141.009 2006-2008
Native Birdlife and Forests of Volcano
by Paul C. Banko
16 May 2008
Introduction
I wish to testify to the Hawaii County Council about changes in the native birdlife and
forest that I have witnessed in my many years as a resident of Volcano. I have lived in
Volcano since 1966. I first became familiar with the birds and forests of Hawaii through
my father, Win Banko, who was the first federal endangered species biologist in Hawaii.
I accompanied him on field trips while still in high school, and I began my own wildlife
career after completing college in 1972. I later earned a Ph.D. in Wildlife Science at the
University of Washington in 1988. Having lived most of my life in Volcano and having
always had a keen interest in native birds, I have had the opportunity to observe profound
changes in the birdlife of our community.
Extinction of populations and species
I remember vividly the `i`iwi, which could be found commonly around my family's home
and throughout Volcano during the 1960's and 1970's. Now this energetic, charismatic
bird is restricted to more remote areas of forest along with several species that were much
rarer in Puna during my early years. Tragically, the `6`u has disappeared throughout the
islands, the only place on earth where they ever existed. Even though I have made the study of
Hawaiian birds my profession, it is remarkable and disheartening to me that I should have
witnessed the local or global loss of so many species just during my lifetime.
Loss of forest through development
Many serious threats have caused extinctions of some Hawaiian bird species and declines
in the populations of others. Our native birds suffer from many new predators, diseases,
and competitors that were not part of the environment in which they evolved.
Additionally, forest habitats have been degraded by many introduced animals, such as
pigs and cattle. Another major threat to our native birds is forest clearing and
fragmentation by people.
Effects of forest fragmentation
Anyone can understand how clearing large tracts of forest harms the birds that live there.
However, the effects of clearing or thinning smaller tracts, such as house lots, are less
obvious. Forest fragmentation poses major problems for birds as well as many insects
and plants.
1. Edge effects. When house lots are cleared in the forest, the edge or margin of the
forest increases disproportionately to the remaining area of forest. This is
important because environmental conditions change abruptly at the forest edge.
Sunlight and wind penetrate the vegetation more deeply, causing drier conditions
that may be unfavorable to some of the native plant species while favoring some
alien species.
2. Alien invasion. Edges provide ready access into native forest for many alien
weeds and pests, to the detriment of native species. For example, cats and other
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predators of native birds frequently patrol edges of native vegetation. Many
weeds thrive on the disturbance caused by clearing the forest. Mosquitoes and
other insect pests may easily spread along corridors and openings created in the
forest.
3. Smaller habitat patches. Forest clearing results in a patchwork of habitat pieces
that only decrease in size as more areas are cleared over time. Many species
cannot sustain themselves in small habitat patches, and some species may not be
able to move between patches or they may be more vulnerable to threats when
they do so.
4. Population isolation. As the forest becomes fragmented, populations become
more isolated. Isolation makes it more difficult for individuals to find mates, for
example, and some plants may not attract pollinators or seed dispersers. Small,
isolated populations are much more at risk of extinction than are larger
populations or small populations that are close to others.
Minimizing the extent of forest clearing is one of the most effective ways we have of
preserving thriving communities of native birds, insects, and plants. I encourage the
Council to consider in their planning the importance of maintaining native biodiversity.
Doing so will improve the quality of our lives as well as the integrity of our natural
heritage. Thank you for your attention.
Respectfully,
Paul C. Banko, Ph.D.
Volcano
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