From bergdahl@wolfenet.com Tue Jan 5 13:12:39 1999 Received: from mxu4.u.washington.edu (mxu4.u.washington.edu [140.142.33.8]) by lists.u.washington.edu (8.9.1+UW98.09/8.9.1+UW98.09) with ESMTP id NAA24120 for ; Tue, 5 Jan 1999 13:12:38 -0800 Received: from wolfenet.com (ratty.wolfe.net [204.157.98.9]) by mxu4.u.washington.edu (8.9.1+UW98.09/8.9.1+UW98.09) with ESMTP id NAA14409 for ; Tue, 5 Jan 1999 13:12:38 -0800 Received: from unknown (sea-ts3-p39.wolfenet.com [205.163.74.39]) by wolfenet.com (8.8.8/8.8.8) with SMTP id NAA28659; Tue, 5 Jan 1999 13:12:09 -0800 (PST) Message-ID: In-Reply-To: References: Conversation with last message X-MSMail-Priority: Normal X-Priority: 3 To: wean@whidbey.net, BogStomper@aol.com Cc: wnpsmail@cornetto.chem.washington.edu, consbio@u.washington.edu, nwn@www.wa.gov, MattN@co.island.wa.us MIME-Version: 1.0 From: "James Bergdahl, Conservation Biology Center" Subject: Puget Sound island biogeography Date: Tue, 05 Jan 99 13:14:19 PST Content-Type: text/plain; charset="ISO-8859-1"; X-MAPIextension=".TXT" Content-Transfer-Encoding: 7bit I have lots of evidence (long-term field surveys) on the distribution and abundance of flightless forest insects (carabid beetles) from 60 islands in the San Juan and Gulf islands that indicate many kinds of strong, local island biogeographic effects. The same is undoubtedly true for other islands in the Puget Sound region. For instance, as with vine maples on Whidbey Island, one of the most common and widespread flightless forest carabid (Pterostichus pumilus) on the adjacent mainland has yet to be discovered in the San Juans. It is unfortunate that very few systematic efforts have been made to document original (native), species distribution patterns on islands in our region - this natural history is a treasure-trove for ecologcal and evolutionary-biology studies that is being destroyed. It particular, it is unfortunate that the University of Washington has shown little interest in this type of research given their ecology and conservation biology interests. Anyone interested in the more information on this subject is welcome to contact me at the numbers listed below. James Bergdahl CONSERVATION BIOLOGY CENTER 7330 23rd Ave. NE Seattle, WA 98115 Ph 206.523.0580 Fx 206.523.4314 Email bergdahl@wolfenet.com ---------- > Question unrelated to Smith prairie: is vine maple native on Whidbey Island? > Marcia Fischer > > Marcia: > Acer circinatum is not native to Whidbey Island. Chalk it up to island > biogeography in fact, rather than in theory. I can always tell a consultant > who hasn't left their mainland office or didn't actually look when they > came over here. They include A. circinatum as occuring at the site of some > proposed development or mtiigation. I've had a standing offer for nearly > ten years now, to one and all, of $100 to anyone who can show me apparently > naturally occuring (i.e. not introduced) A. ciricinatum on Whidbey Island. > No one's even tried to collect. Of course, $100 is not worth as much now as > when I first made the offer. > > Last spring, at a hearing before the Planning Commission on the County's > much belated GMA fish and widllife habitat conservation ordinance, the > County's consultant (Andy Castelle) professed great skepticism at our > claims that the small island streams and creeks were relatively as > important in the island context to maintanence of biodiversity and > ecological functioning as the large riverine systems were to the mainland. > He pretty much stated that he didn't believe in island biogeographic > effects, or the theory at all. Then, while discussing the ornamental > qualities of vine maple, he asked if it grew here. Naturally, Marianne and > I piped up from the audience in perfect unison, "Not native here". > Castelle, in some apparent amazement, turned and asked incredulously, "It > doesn't grow here?" Again in perfect unison, we said (loudly), "Island > biogeography." However, judging by the absurdly small stream buffers > recommended by Castelle, I don't think this evidence convinced him. > > However, there is A. glabrum on the shore in Coupeville. But several common > or widely distributed lowland Puget species do not grow on Whidbey: > Dicentra formosa (it has been introduced and is becoming naturalized) and > all Trillium spp. > There are some interesting disjuncts: > Iris missouriensis (purportedly the last population west of the Cascades > and seriously threatened by development), Chrysopsis villosa, Opuntia > fragilis, Carex pansa, Juniperus scopulorum, and the previously mentioned > Acer glabrum. > > While the peculiar biogeography of Whidbey Island is fascinating, the real > issue I'm trying to get at is found in exploring the question, "Should we > plant vine maple on Whidbey Island?" > This question in turn is a surrogate for an issue that constantly recurs in > a larger context: > Should the target plant community in a restoration (or mitigation) be > modeled on and limited to the species composition of the best available > local vegetation or another explicit reference site, or should the species > diversity of the target community be maximized within the much larger > boundaries of the regional flora? > > Perhaps vine maple introduced into Whidbey island forests would increase > structural diversity? It would certainly change nutrient cycling. To what > effect on the exisitng species and systems? > While we cannot predict exactly what efects such an introduction would > have, we do know that introductions of species far removed from their > natural range may have far reaching impacts on the invaded ecosystem's > composition, structure, and function. However, vine maple commonly occurs > in forest understories nearby on the mainland in plant associations that > appear very similar to those on Whidbey Island, except that vine maple is > not present on Whidbey. So it appears doubtful that introducing vine maple > to Whidbey Island would have the disruptive ecological impacts of an > aggressive non-native. Of course, we can not know that for sure. > > I believe that concerns about weed introductions aside, there is an even > more fundamental reason why vine maple should not be introduced to Whidbey > Island and, by extension, diversity should not be maximized in each and > every restoration or mitigation revegetation. > > The naturally depauperate Whidbey forest flora has a different evolutionary > potential than the mainland forest flora. Over time, even subject to the > same abiotic forces and processes as occur on the mainland, the island > species will evolve differently than the mainland species. This is not only > because of the isolating effects on the island species' gene pools, but > because that flora is simply different. The absence of vine maple > forecloses some developmental pathways and opens other opportunities. > Intraspecific relations, be they competitive, neutral, beneficial, > parasitic, or symbiotic, impose unique selection pressures on a given > area's inhabitants. The less variation between the species composition of > different areas, the less difference there will be in the selection > pressures caused by those differences in species composition. > > We humans are very good at creating sameness and very bad at creating > difference. When we attempt to maximize diversity everywhere, we actually > restrict its future development. by creating (or at least encouraging) > homogeneity that lessens evolutionary potential. And for me, the ultimate > goal of preservation and restoration is to maintain evolutionary potential. > And that's why I don't believe vine maple should be introduced to Whidbey > Island unless there is a very compelling reason to do so. > > As for the iguanas, they'll hitchhike on an inner tube or buy a ferry > ticket to Whidbey when they're good and ready. > > Discussion anybody? > -Steve > > .