Subject: [Tweeters] Range Expansions
Date: Apr 3 23:59:05 2006
From: J & B Adamowski LaComa - jennandbryan at msn.com


A quick search on MSN under "Russian olive Washington state" turned up a few interesting sites to browse. 2 that were notable claim that the Russian Olive is disrupting the ecosystem by replacing native species. They do acknowledge that there is tremendous benefits to some species of birds but overall promotes less diversity. They go on to list many species region by region that are losing out to the Russian Olive or Eleagnus angustifolia. Red Twig Dogwood, Aspen, Willow and Cottonwood or just a few that are listed for our region. Both sites claim that Eleagnus angustifolia replaces these by out competing for light and space. The seeds are able to move through a bird digestive track and can last for more than 3 years without germinating.
I have not seen any areas where Russian Olive completely takes over an area. Places like Toppenish have huge groves of Eleagnus and have mixed in nicely with Willow, Alder etc....and seem to promote a higher diversity of animal species. Has anyone found this to be not true? Are there any biologists out there that have studied bird populations and species diversity and tracked it with the arrival of Eleagnus angustifolia to the region? I suppose it would be difficult to discern if this plant was the cause or climactic shifts, or habitat loss, or...................

Bryan
Shoreline, Wa.
jennandbryan at msn.com



----- Original Message -----
From: SGMlod at aol.com
Sent: Monday, April 03, 2006 8:32 PM
To: jennandbryan at msn.com
Cc: Tweeters at u.washington.edu
Subject: Re: [Tweeters] Range Expansions

Hello Bryan and The Rest of Tweeterdom

Bryan and I have had a wee discussion about introduced species.

Many of these have been a huge boon, at least to certain species.

If one reads Jewett et al, it is hard to believe that the sparrow increase isn't real. Swamp Sparrows, perhaps, are recorded more due to increased observers, but how about the increases in wintering WC Sparrows, GC Sparrows, Lincoln's Sparrows? I think blackberry brambles play a large role. A whole host of species utilize Russian Olives, and I've no doubt that wintering YR Warblers, Hermit Thrushes, solitaires, and eastside Varied Thrushes would be far less common were it not for this plant. Bewick's Wrens also seem dependent on it in many places e. of the Cascades. Finally, Eurasian Milfoil has been a huge benefit to scaup, coots, wigeon and other waterfowl/birds.

I am certain these species have some detrimental effects, but they grow in many places so incredibly altered that "restoring" them is impossible. And when one says "restore," one must ask to when? Before white man, before humans, before the ice ages? I am not being silly. This world is not static, especially over the last 2 million years.

I've a friend high up in WDFW and another high up in the NWR system who think the real answer is a high diversity of quality habitats. Some of these would include introduced species such as Russian Olive, and some would have these introduced species removed. It is better to try to preserve/improve the high quality more pristine areas than try to take out every blackberry bramble and Russian Olive tree. Indeed, for many birds, the latter would be detrimental. Unfortunately, the government has currently taken a "if its not native, it needs to go" stance. Such as squashed the Russian Olive woodland that provided so much habitat for so many birds on the totally artificial habitat created by ag runoff at Wahluke Slope. Ideally, such an area would be a mix of willow and olive. Maybe someday it will, but right now, a number of Song Sparrows, WC Sparrows, towhees, Hermit Thrushes, etc have lost their wintering grounds. If it grows back solid willow, maybe the Song Sparrows will use it, but none of the others will.

Similarly, the move to destroy every artificially created freshwater/brackish wetland in w. Washington to re-establish "natural" tidelands would be a huge blow to shorebirds, many of whom depend on these created wetlands as high tide feeding areas/roost sites. The enormous numbers and diversity of shorebirds that use Crockett Lake and Port Susan Bay are no accident. Same for Iona Island in BC. Shorebirds are particularly dependent on high quality areas for refeuling, or they don't make it to the next stop hundreds of miles away. The amount of salmon habitat would be increased by a tiny fraction if these areas are eliminated, yet a huge percentage of w. Washington's non-tidal shorebird habitat would be erased.

Sadly, this topic is exceptionally complicated. Those espousing complete eradication of introduced species are ignoring real life realities. Those suggesting we abandon rehabilitation of "natural" habitats are equally misled.

An interesting example was given in the book that I cited in a much earlier post. It was by a guy whose specialty was, yes, the feces of extinct mammals. He suggested that the non-native burro and horse populations are replacing species wiped out by humans about 10000 years ago. Burros were removed from part (all?) of the Grand Canyon National Park because they were supposedly detrimental to the mesquite. He studied the situation and found that mesquite declined after the burros were removed. He looked at their feces and they weren't predominantly eating branches/foliage, but were eating seed pods and actually spreading the mesquite.

I am not suggesting we introduce Monk Parakeets throughout Washington or plant Russian Olives in pristine habitats, but I am suggesting that we re-evaluate our knee-jerk reaction to non-natives.

Some of the species we discussed that are on the increase are increasing, I believe, because of an increasingly milder climate. Others, however, are the beneficiaries of some of these introduced plants. And I am not just talking Eur Starlings, but birds like Greater Scaup.

Cheers
Steven Mlodinow
Everett WA