« This quantum stuff just doesn't add up | Main | Space experiments should be done on the cheap »

Alien birds may be last hope for Hawaiian plants

Invasive birds are now the main reason that some native forests thrive.

After years of fighting the threats posed by foreign species on the Hawaiian islands, conservationists have discovered that invasive birds may now be the only hope left for the survival of some native plants.

Read the story here.

Posted by Nicola Jones on September 28, 2007
Categories: | | Comments (7) | TrackBacks (0)

TrackBack

TrackBack URL for this entry:
http://blogs.nature.com/cgi-bin/mt/mt-tb.cgi/3596

Comments

Upon sending the story to hiplants@hawaii.edu, I received this reminder of a reply:

Dear Thomas,

This is an interesting analysis of the data. Native birds are poor native
seed dispersers; alien birds are good native seed dispersers, therefore,
alien birds are helping native plants.

Did anyone think that, maybe,
native plants were adapted for small dispersal distances (e.g., many, many
seeds falling directly beneath the plant ensures future occupation of this
favorable habitat)?

aloha,
Bruce

**********************************************************************
Bruce P. Koebele, PhD. Phone: (808) 695-5009
84-740 Kili Drive, #430
Waianae, Hawaii 96792

Posted by: Thomas Galioto | October 1, 2007 12:57 AM

Drake's 'dilemma' is more than just a problem of choosing between maintaining 'native' plant populations and purifying an ecosystem by suppressing 'alien' birds. At stake is admitting that even recent arrivals to Hawaii are actually assimilated into a dynamic, emergent association, rather than forcing themselves as invaders on a hapless, idyllic community, or infecting some once-healthy body. Even if one uncomfortably claims that Hawaii has been bingeing on new biota since it was added to our maps, it doesn't follow that a program of nostalgic purges can reinstate the prior condition. The burden remains on reactionary conservationists to show that intervening on behalf of a legendary ancien regime will ultimately produce more benefits than harms. The dubious moral superiority of co-victimhood, the "living alone in a world of wounds" effectively reconstituted ecological science, but it was never an adequate basis of authority for deciding how the world, or even Hawaii, "ought" to be configured. And it certainly didn't exempt ecologists from producing our own unintended consequences.

Posted by: Matt Chew | October 1, 2007 07:40 PM

Upon sending the story to hiplants@hawaii.edu, I received this second informational reply:

Here are our some observations:

At the Waimea Valley Audubon Center frequently there are small flocks of
waxbills (Estrilda spp.), avadats (Amandava sp.), and munias/mannikins
(Lonchura spp.) feeding/foraging on native sedges (Cyperus javanicus, C.
trachysanthos, C. laevegatus, C. polystachyos, Fimbristylis dichotoma, F.
cymosa), native rushes (Schoenoplectus tabernaemontani, Bulboschoenus
maritimus, Eleocharis obtusa) and native grasses (Eragrostis varabilis) we
have planted out as well still our nursery as potted plants. I have never
discouraged this foraging behavior nor deprive them of this food source with
the likelihood of seed dispersal. Too, our resident ‘alae ‘ula, or Hawaiian
moorhen, normally feed on several of the above plants as well.

I have always believed that our incredibly invasive increase in Guinea grass
(Panicum maximum) has been largely due to seed-eating many passerine birds
mentioned above. There has been a major of increase of both birds and this
grass over the decades.

Too, we have witnessed Japanese white-eye, or mejiro, sipping nectar from
the flowers of native plants such as ‘ohi‘a, hibicuses, Kokia spp., ‘ilima,
abutilons, koai‘a, and lobeliads (Delissea rhytidosperma, Cyanea truncata,
C. angustifolia) that we have planted out or in the nursery. And though we
have a resident population of leiothrix, I have not personally observed them
partaking of any fruits or flowers. They seem to forage, and come and go.
But the mejiro may very possibly be acting as accidental pollinators ...who
really knows.

Does the end justify the means? I wouldn't attempt to answer that myself.
These are just my observations.

Incidentally, some of our native birds that do eat native fruits for
dispersal are nene, 'alala, and 'oma'o (though probably only significant on
the Big Island) …to name some that come to mind.

This is just food for thought.

Aloha,
DavE

PS Here's another interesting site on the subject
http://www.bioedonline.org/news/news.cfm?art=3628

David W. Eickhoff

Waimea Valley Audubon Center
59-864 Kamehameha Hwy.
Haleiwa, HI 96712
Nursery Manager
(808) 638-9199
Fax: (808) 638-9197
E-Mail: deickhoff@audubon.org

Posted by: Thomas Galioto | October 1, 2007 08:54 PM

Upon sending the story to hiplants@hawaii.edu, I received this third reply from Michael DeMotta mdemotta@HOTMAIL.COM :

Japanese White Eye is prevalent in mesic and wet forest all over Kauai. They do feed regularly on ohia and many other plants and are probably pollinators for a lot of them but I don't think all plants benefit. If you observe the white eye feeding on hibiscus, Kokio, and Hibiscadelphus, they take the nectar from between the petals, bypassing the stamin. So they don't engage the pollen. I have seen this feeding habit many times. Still, ohia seems to benefit.

As for seed dispersal, let us not forget all those flightless birds that have been extinct for a long time now. Many species have poor portability now because they were probably food for these big birds that carried the seed far from the source. Big seeded fruit like Ochrosia for sure but even fleshy fruit like Rauvolfia and Rubus would have been tasty to these flightless birds.

Mike

Posted by: Thomas Galioto | October 1, 2007 08:57 PM

Before to make any conclusion, we should continued with the next questions. For example: What about environment patterns that could have affected native plant seedling answer (e.g. water availability increased) and other dispersal agents (e.g. small mammals) that could have helped dispersion. The exotic birds feeding could have been influenced by food availability. We know about foraging habits of these birds across the time?.

Posted by: Rosa Manrique | October 2, 2007 05:35 PM

Still responding after I sent the story to hiplants@hawaii.edu, I received this reply from:

Rick B rick.ck.barboza@GMAIL.COM
Sent Sunday, October 7, 2007 5:04 am
To HIPLANTS-L@HAWAII.EDU
Subject Re: [HIPLANTS-L] Alien birds may be last hope for Hawaiian plants

Aloha Kekama and all,

For as much as I hate alien birds, trust me I really, really do, I've noticed the same thing at our restoration site at Kalaeloa and perhaps Bruce has noticed it as well. There are tons and tons of droppings from Red-Vented Bulbuls with nothing but naio (Myoporum sandwicense subsp. stellatum) seeds in them.

I've seen rocks below perches with thousands of seeds on them and especially around our irrigation heads where they come to drink occasionally.

Here's another one, I've seen maiapilo (Caparis sandwichiana) seedlings growing out of rodent holes there too.

Now what? keep the rats, mice and mongoose? Give me my BB gun and I'll show you my answer.

Just kidding... but not really. Interesting article, it raises good debate.

Mahalo,
Rick Barboza

Posted by: Thomas Galioto | October 7, 2007 11:52 PM

Upon sending the story to hiplants@hawaii.edu, I received this fifth reply.

EICKHOFF, David deickhoff@AUDUBON.ORG

Sent Sunday, October 7, 2007 10:22 am
To HIPLANTS-L@HAWAII.EDU
Subject Re: [HIPLANTS-L] Alien birds may be last hope for Hawaiian plants

Just to add to Rick's comment about Kalaeloa avian activity, I have noticed red-vented bulbuls feeding on ripe maiapilo fruits. And although I have noticed them in and around the naio at Barber's Point, I don't recall seeing them feeding on them. So this is a really cool observation for this rare naio subspecies! Did you notice any seedlings?

This also raises questions about rats and mice distributing native seeds, which generally destroy seeds. If they are growing out of rodent holes: Are they storing some seeds for "winter", nah, ...for leaner times? Are the maiapilo seeds toxic to rodents so that they eat the fruits and discard seeds?

Aloha,
DavE


David W. Eickhoff
Waimea Valley Audubon Center
59-864 Kamehameha Hwy.
Haleiwa, HI 96712
Nursery Manager
(808) 638-9199
Fax: (808) 638-9197
E-Mail: deickhoff@audubon.org

Posted by: Thomas Galioto | October 8, 2007 12:57 AM

Post a comment

Comments will be reviewed by staff before being published. You can be as critical or controversial as you like, but please don't get personal or offensive, and do keep it brief. Excessively long entries may be cropped. Remember this is for feedback and discussion - not for publishing papers or press releases.

We strongly encourage you to use your real, full name. Email addresses are required: this is just in case we need to discuss your comment with you privately. They won’t be published.


Please enter the numbers you see below - this helps us to cut down on spam. Note that attempting to post within 30 seconds of hitting ‘preview’ or ‘post’ can cause the system to think you are spamming the site. If you are having trouble with this system, you can instead e-mail a comment to 'inthefield at nature.com'.

Search