Re: [ECOLOG-L] Responses to Davis_etal..Nature article on invasive species (UNCLASSIFIED)
A couple of regional examples, Melissa: Reed canarygrass in wetlands and Armenian (Himalayan) blackberry in oak savannas. Warren W. Aney Senior Wildlife Ecologist Tigard, OR -Original Message- From: Ecological Society of America: grants, jobs, news [mailto:ECOLOG-L@LISTSERV.UMD.EDU] On Behalf Of Kirkland, Melissa J NWP Sent: Thursday, 28 July, 2011 09:36 To: ECOLOG-L@LISTSERV.UMD.EDU Subject: Re: [ECOLOG-L] Responses to Davis_etal..Nature article on invasive species (UNCLASSIFIED) Classification: UNCLASSIFIED Caveats: NONE As part of this debate, and I give nod to those that have declared the original article as over-simplified, there are vast differences in the impacts of invasive species that displace desirable species, and non-native species that simply naturalize in an area with minimal impacts to the ecosystem. Which brings up another concept for me. Ecosystem functions and how those functions collapse in the face of replacement of native plant communities with monocultural stands of invasive species. Just my humble thoughts. Melissa Kirkland Natural Resource Specialist US Army Corps of Engineers Eugene, Oregon Classification: UNCLASSIFIED Caveats: NONE
Re: [ECOLOG-L] Responses to Davis_etal..Nature article on invasive species (UNCLASSIFIED)
Classification: UNCLASSIFIED Caveats: NONE As part of this debate, and I give nod to those that have declared the original article as over-simplified, there are vast differences in the impacts of invasive species that displace desirable species, and non-native species that simply naturalize in an area with minimal impacts to the ecosystem. Which brings up another concept for me. Ecosystem functions and how those functions collapse in the face of replacement of native plant communities with monocultural stands of invasive species. Just my humble thoughts. Melissa Kirkland Natural Resource Specialist US Army Corps of Engineers Eugene, Oregon Classification: UNCLASSIFIED Caveats: NONE
Re: [ECOLOG-L] Responses to Davis_etal..Nature article on invasive species (UNCLASSIFIED)
Ecolog and M. Kirkland: Declarations in scientific, scholarly, or intellectual intercourse have long been customarily required to be based upon specifics. In the spirit of such enquiry, specific defects observed in another's statement should be cited, followed by a relevant exposition of relevant facts and sources, the critic's reasoning, and clear conclusions. Perhaps I am out-of-date; if this custom has been supplanted by opinion (arguing from authority?) or something superior, I should like to become informed of the basis upon which such alternative is grounded. WT - Original Message - From: Kirkland, Melissa J NWP melissa.j.kirkl...@usace.army.mil To: ECOLOG-L@LISTSERV.UMD.EDU Sent: Thursday, July 28, 2011 9:35 AM Subject: Re: [ECOLOG-L] Responses to Davis_etal..Nature article on invasive species (UNCLASSIFIED) Classification: UNCLASSIFIED Caveats: NONE As part of this debate, and I give nod to those that have declared the original article as over-simplified, there are vast differences in the impacts of invasive species that displace desirable species, and non-native species that simply naturalize in an area with minimal impacts to the ecosystem. Which brings up another concept for me. Ecosystem functions and how those functions collapse in the face of replacement of native plant communities with monocultural stands of invasive species. Just my humble thoughts. Melissa Kirkland Natural Resource Specialist US Army Corps of Engineers Eugene, Oregon Classification: UNCLASSIFIED Caveats: NONE - No virus found in this message. Checked by AVG - www.avg.com Version: 10.0.1390 / Virus Database: 1518/3793 - Release Date: 07/28/11
Re: [ECOLOG-L] Responses to Davis_etal..Nature article on invasive species
Wayne, the juniper invasion in the northern Great Basin sort of defines one boundary for what invasiveness really is. In this case the endemic western juniper begins to dominate the landscape because of reduction or elimination of wildfires. A typical wildfire managed landscape will have a diversity of shrub and grass communities with junipers limited to rocky ridges and other areas less vulnerable to wildfire. A landscape dominated by juniper will have less diversity and less productivity. There are other similar examples of how wildfire control is resulting in changed native communities, e.g., Oregon white oak woodlands in western Oregon valleys being overwhelmed by endemic Douglas-fir and shrubby undergrowth; open Ponderosa pine forests in the Blue Mountains changing into denser mixed fir and pine forests. An argument can be made that since wildfire is the natural agent maintaining certain conditions, lack of wildfire just allows another natural succession to occur. In the cases described management such as cutting, thinning and controlled burns may be necessary to maintain or produce desired and healthier conditions. Warren W. Aney Tigard, Oregon -Original Message- From: Wayne Tyson [mailto:landr...@cox.net] Sent: Thursday, 07 July, 2011 15:17 To: Warren W. Aney; ECOLOG-L@LISTSERV.UMD.EDU Subject: Re: [ECOLOG-L] Responses to Davis_etal..Nature article on invasive species Warren: How about giving us a rundown on the juniper invasion at Steen's Mountain, and your take on the BLM's actions there? WT - Original Message - From: Warren W. Aney a...@coho.net To: ECOLOG-L@LISTSERV.UMD.EDU Sent: Wednesday, July 06, 2011 10:53 PM Subject: Re: [ECOLOG-L] Responses to Davis_etal..Nature article on invasive species Geoff, mantras such as you cite are good as long as we recognize that they tend to simplify grand complexity. The more or less natural barred owl invasion of spotted owl habitat resulting in population displacement and reduction is a good example of how even natural evolution/change can be seen as adverse. Warren W. Aney Senior Wildlife Ecologist Tigard, Oregon -Original Message- From: Ecological Society of America: grants, jobs, news [mailto:ECOLOG-L@LISTSERV.UMD.EDU] On Behalf Of Geoffrey Patton Sent: Wednesday, 06 July, 2011 17:40 To: ECOLOG-L@LISTSERV.UMD.EDU Subject: Re: [ECOLOG-L] Responses to Davis_etal..Nature article on invasive species My wife and I were discussing this topic the other day while hiking through a Maryland park infested with Chinese garlic mustard and Japanese stilt grass (among other invasives). We'd biked past slopes of kudzu and came from Florida's expanses of Brazilian peppers and punk trees. Certainly, we appreciate that Science will note positive aspects in selected situations where there are temporally-beneficial effects. However, the mantra that remains to be overturned is that Any change from the natural evolution of an ecosystem is, by definition, adverse. Ecosystems took millions of years of experimentation to achieve a deep dynamic balance. Upset by out-of-control human intervention can tilt against a healthy balance and remains counter to maintenance of diversity. Cordially yours, Geoff Patton, Ph.D. 2208 Parker Ave., Wheaton, MD 20902 301.221.9536 --- On Wed, 7/6/11, Christopher M Moore cmmo...@unr.edu wrote: From: Christopher M Moore cmmo...@unr.edu Subject: Re: [ECOLOG-L] Responses to Davis_etal..Nature article on invasive species To: ECOLOG-L@LISTSERV.UMD.EDU Date: Wednesday, July 6, 2011, 6:30 PM Thanks for the post David. As a newcomer to science (working on my Ph.D.), there were some lingering questions I had while reading Davis et al. and the responses: Is this how we want to move forward as a science? What does it mean when we resort to gathering signatures? Is this how our science should work? What does it contribute? How should we deal with issues that are debated in a more productive and less polarizing manner? Personally, I don't think that petitioning changes ecology nor any other natural phenomena. I would like to add Peter Kareiva's blog on the matter to be added to this discussion: http://blog.nature.org/2011/06/invasive-species-fight-mark-davis-peter-karei va/ Opening of the piece: A famous person once observed that the signature of a civilized mind is the ability to hold two seemingly contradictory ideas in one's head at the same time. This is exactly what conservation must learn to do when it comes to introduced (or what we often call non-native or invasive) species. Cheers, Chris On Jul 6, 2011, at 2:18 PM, David Duffy wrote: Date: Wed, 06 Jul 2011 19:52:27 + Forwarded from rom: Shyama Pagad s.pa...@auckland.ac.nz on Aliens-L list server Correspondence Nature Vol 475 July 7 2011 -- Non-natives: 141 scientists object We the undersigned feel that in advocating a change in the environmental management of introduced species (Nature 474, 153-154; 2011
Re: [ECOLOG-L] Responses to Davis_etal..Nature article on invasive species
Honorable Forum: While I tend to find something with which to agree in most posts, I suggest that the scientific approach to such discussions tend more toward the specific and less toward the general. For example when asserting a conclusion about something (e.g., the Davis, et al paper or an assertion therein), it would help in interpreting the refutation if the refuter included an exact quote from the offending paper/assertion and a full statement that explains just what the defects are upon which the refutation is based. WT Note to David: Regarding the quote you included, some famous person needlessly invokes authority when the statement can stand on its own merit or fall on its own deficiencies with or without invoking authority. While this is a growing habit among academics, I question its value. I could be wrong, of course, so what would be the scientific (disciplined, scholarly, non-manipulative) way of demonstrating my error? Rather than using the famous person phrase, I would simply note that it was not of my own making, putting it in quotes, and stating that I had forgotten (or lacked the time or gumption to look it up) who said or wrote it. Of course you are quoting someone else, and you even provide a link, for which thanks. Perhaps the sole responsibility of the error lies with the person whom you are quoting some other source, but if the originator was indeed famous, the passing of the lazy buck has got to stop someplace--red meat for the scholar or other stickler. Otherwise, the error will be perpetuated in the literature. Richard Minnich wrote a delightful paper on this years ago, demonstrating how perpetuation such errors can send colleagues on some expensive and time-consuming wild goose chases (New Yorkers will please disregard) and expose a whole chain of sloppy scholarship. I look forward to your posts in which you fearlessly take on the answers to your questions and probe deeply into the merits and deficiencies of the issues, statements, assertions, and refutations coming out of this discussion. - Original Message - From: Christopher M Moore cmmo...@unr.edu To: ECOLOG-L@LISTSERV.UMD.EDU Sent: Wednesday, July 06, 2011 3:30 PM Subject: Re: [ECOLOG-L] Responses to Davis_etal..Nature article on invasive species Thanks for the post David. As a newcomer to science (working on my Ph.D.), there were some lingering questions I had while reading Davis et al. and the responses: Is this how we want to move forward as a science? What does it mean when we resort to gathering signatures? Is this how our science should work? What does it contribute? How should we deal with issues that are debated in a more productive and less polarizing manner? Personally, I don't think that petitioning changes ecology nor any other natural phenomena. I would like to add Peter Kareiva's blog on the matter to be added to this discussion: http://blog.nature.org/2011/06/invasive-species-fight-mark-davis-peter-kareiva/ Opening of the piece: A famous person once observed that the signature of a civilized mind is the ability to hold two seemingly contradictory ideas in one’s head at the same time. This is exactly what conservation must learn to do when it comes to introduced (or what we often call “non-native” or “invasive”) species. Cheers, Chris On Jul 6, 2011, at 2:18 PM, David Duffy wrote: Date: Wed, 06 Jul 2011 19:52:27 + Forwarded from rom: Shyama Pagad s.pa...@auckland.ac.nz on Aliens-L list server Correspondence Nature Vol 475 July 7 2011 -- Non-natives: 141 scientists object We the undersigned feel that in advocating a change in the environmental management of introduced species (Nature 474, 153–154; 2011), Mark Davis and colleagues assail two straw men. First, most conservation biologists and ecologists do not oppose non-native species per se — only those targeted by the Convention on Biological Diversity as threatening “ecosystems, habitats or species”. There is no campaign against all introductions: scarcity of resources forces managers to prioritize according to the impact of troublesome species, as in the Australian Weed Risk Assessment. Second, invasion biologists and managers do not ignore the benefits of introduced species. They recognize that many non-native species curtail erosion and provide food, timber and other services. Nobody tries to eradicate wheat, for instance. Useful non-native species may sometimes still need to be managed because they have a negative impact, such as tree invasions that cause water loss in the South African fynbos. Davis and colleagues downplay the severe impact of non-native species that may not manifest for decades after their introduction — as occurred with the Brazilian pepper shrub (Schinus terebinthifolius) in Florida (J. J. Ewel in Ecology of Biological Invasions of North America and Hawaii (eds H. A. Mooney and J. A. Drake) 214–230; Springer, 1986). Also, some species
Re: [ECOLOG-L] Responses to Davis_etal..Nature article on invasive species
Geoff, mantras such as you cite are good as long as we recognize that they tend to simplify grand complexity. The more or less natural barred owl invasion of spotted owl habitat resulting in population displacement and reduction is a good example of how even natural evolution/change can be seen as adverse. Warren W. Aney Senior Wildlife Ecologist Tigard, Oregon -Original Message- From: Ecological Society of America: grants, jobs, news [mailto:ECOLOG-L@LISTSERV.UMD.EDU] On Behalf Of Geoffrey Patton Sent: Wednesday, 06 July, 2011 17:40 To: ECOLOG-L@LISTSERV.UMD.EDU Subject: Re: [ECOLOG-L] Responses to Davis_etal..Nature article on invasive species My wife and I were discussing this topic the other day while hiking through a Maryland park infested with Chinese garlic mustard and Japanese stilt grass (among other invasives). We'd biked past slopes of kudzu and came from Florida's expanses of Brazilian peppers and punk trees. Certainly, we appreciate that Science will note positive aspects in selected situations where there are temporally-beneficial effects. However, the mantra that remains to be overturned is that Any change from the natural evolution of an ecosystem is, by definition, adverse. Ecosystems took millions of years of experimentation to achieve a deep dynamic balance. Upset by out-of-control human intervention can tilt against a healthy balance and remains counter to maintenance of diversity. Cordially yours, Geoff Patton, Ph.D. 2208 Parker Ave., Wheaton, MD 20902 301.221.9536 --- On Wed, 7/6/11, Christopher M Moore cmmo...@unr.edu wrote: From: Christopher M Moore cmmo...@unr.edu Subject: Re: [ECOLOG-L] Responses to Davis_etal..Nature article on invasive species To: ECOLOG-L@LISTSERV.UMD.EDU Date: Wednesday, July 6, 2011, 6:30 PM Thanks for the post David. As a newcomer to science (working on my Ph.D.), there were some lingering questions I had while reading Davis et al. and the responses: Is this how we want to move forward as a science? What does it mean when we resort to gathering signatures? Is this how our science should work? What does it contribute? How should we deal with issues that are debated in a more productive and less polarizing manner? Personally, I don't think that petitioning changes ecology nor any other natural phenomena. I would like to add Peter Kareiva's blog on the matter to be added to this discussion: http://blog.nature.org/2011/06/invasive-species-fight-mark-davis-peter-karei va/ Opening of the piece: A famous person once observed that the signature of a civilized mind is the ability to hold two seemingly contradictory ideas in ones head at the same time. This is exactly what conservation must learn to do when it comes to introduced (or what we often call non-native or invasive) species. Cheers, Chris On Jul 6, 2011, at 2:18 PM, David Duffy wrote: Date: Wed, 06 Jul 2011 19:52:27 + Forwarded from rom: Shyama Pagad s.pa...@auckland.ac.nz on Aliens-L list server Correspondence Nature Vol 475 July 7 2011 -- Non-natives: 141 scientists object We the undersigned feel that in advocating a change in the environmental management of introduced species (Nature 474, 153154; 2011), Mark Davis and colleagues assail two straw men. First, most conservation biologists and ecologists do not oppose non-native species per se only those targeted by the Convention on Biological Diversity as threatening ecosystems, habitats or species. There is no campaign against all introductions: scarcity of resources forces managers to prioritize according to the impact of troublesome species, as in the Australian Weed Risk Assessment. Second, invasion biologists and managers do not ignore the benefits of introduced species. They recognize that many non-native species curtail erosion and provide food, timber and other services. Nobody tries to eradicate wheat, for instance. Useful non-native species may sometimes still need to be managed because they have a negative impact, such as tree invasions that cause water loss in the South African fynbos. Davis and colleagues downplay the severe impact of non-native species that may not manifest for decades after their introduction as occurred with the Brazilian pepper shrub (Schinus terebinthifolius) in Florida (J. J. Ewel in Ecology of Biological Invasions of North America and Hawaii (eds H. A. Mooney and J. A. Drake) 214230; Springer, 1986). Also, some species may have only a subtle immediate impact but affect entire ecosystems, for example through their effect on soils. Pronouncing a newly introduced species as harmless can lead to bad decisions about its management. A species added to a plant community that has no evolutionary experience of that organism should be carefully watched. For some introductions, eradication is possible. For example, 27 invasive species have been eradicated from
Re: [ECOLOG-L] Responses to Davis_etal..Nature article on invasive species
I know this is very trivial and adds nothing to the debate, but it represents a stereotype of scientists as one dimensional. The blog post from nature (http://blog.nature.org/2011/06/invasive-species-fight-mark-davis-peter-kareiva/) Opens with the line:A famous person once observed that the signature of a civilized mind is the ability to hold two seemingly contradictory ideas in one’s head at the same time. This is exactly what conservation must learn to do when it comes to introduced (or what we often call “non-native” or “invasive”) species. I find this somewhat offensive that the person who said this, F. Scott Fitzgerald in his 1936 essay The Crack-up, is simply a famous person. On top of that he's misquoted. It says nothing of being civilized, but its a test of first rate intelligence. I'm not sure why the author neglected to credit his source or get the quote right. I think we should portray ourselves (scientists I mean) as literate well rounded people. Off topic, but it seemed like such an egregious error that I thought it should be corrected. The full quote is as follows: Before I go on with this short history, let me make a general observation – the test of a first-rate intelligence is the ability to hold two opposed ideas in the mind at the same time, and still retain the ability to function. One should, for example, be able to see that things are hopeless and yet be determined to make them otherwise. -- -- -- Edmund M. Hart, PhD. Post-Doctoral Researcher Dept. of Zoology University of British Columbia http://currentecology.blogspot.com http://openwetware.org/wiki/Hart
Re: [ECOLOG-L] Responses to Davis_etal..Nature article on invasive species
Such an interesting read! Conservation is all about contradictions. Like any area of research actually..so that's nothing new. But in conservation, more than others, one needs to pick a side and stick to it..at least for a while. It is true about the environment being in a deep dynamic balance. But just because we have defined it as a 'dynamic balance' in our books and conversations doesn't mean it isn't a contradiction too. What if biological invasions are just another way of the ecosystem trying to cope with the environmental changes, of taking an evolutionary step. Only this time the changes aren't natural but brought about by our actions. Of course we must all have realized by now that the next evolutionary stage will not be as biologically diverse as the one before because we have ensured it won't be. So maybe the answer to managing ecosystems now is to allow these changes and carry out re-introductions in new, suitable habitats rather than historical ones. Maybe we can aid in the evolutionary process by letting go of old ecosystem boundaries and animal ranges. On the other hand, one might argue that if we were to all take this view there'll be nothing left but invasives and deserts and mines. But even that we aren't sure of are we? So who is to say what is the right approach. Just because something was a certain way, doesn't make it right does it! Well, even I don't have a stand on this as yet and I'm trying to find it. This is my biggest concern really..what side will I pick. I would like to believe that maybe we will need to allow ecosystems to achieve a new balance but then..I don't know. Cheers, Payal. On 7 July 2011 06:10, Geoffrey Patton gwpatt...@yahoo.com wrote: My wife and I were discussing this topic the other day while hiking through a Maryland park infested with Chinese garlic mustard and Japanese stilt grass (among other invasives). We'd biked past slopes of kudzu and came from Florida's expanses of Brazilian peppers and punk trees. Certainly, we appreciate that Science will note positive aspects in selected situations where there are temporally-beneficial effects. However, the mantra that remains to be overturned is that Any change from the natural evolution of an ecosystem is, by definition, adverse. Ecosystems took millions of years of experimentation to achieve a deep dynamic balance. Upset by out-of-control human intervention can tilt against a healthy balance and remains counter to maintenance of diversity. Cordially yours, Geoff Patton, Ph.D. 2208 Parker Ave., Wheaton, MD 20902 301.221.9536 --- On Wed, 7/6/11, Christopher M Moore cmmo...@unr.edu wrote: From: Christopher M Moore cmmo...@unr.edu Subject: Re: [ECOLOG-L] Responses to Davis_etal..Nature article on invasive species To: ECOLOG-L@LISTSERV.UMD.EDU Date: Wednesday, July 6, 2011, 6:30 PM Thanks for the post David. As a newcomer to science (working on my Ph.D.), there were some lingering questions I had while reading Davis et al. and the responses: Is this how we want to move forward as a science? What does it mean when we resort to gathering signatures? Is this how our science should work? What does it contribute? How should we deal with issues that are debated in a more productive and less polarizing manner? Personally, I don't think that petitioning changes ecology nor any other natural phenomena. I would like to add Peter Kareiva's blog on the matter to be added to this discussion: http://blog.nature.org/2011/06/invasive-species-fight-mark-davis-peter-kareiva/ Opening of the piece: A famous person once observed that the signature of a civilized mind is the ability to hold two seemingly contradictory ideas in one’s head at the same time. This is exactly what conservation must learn to do when it comes to introduced (or what we often call “non-native” or “invasive”) species. Cheers, Chris On Jul 6, 2011, at 2:18 PM, David Duffy wrote: Date: Wed, 06 Jul 2011 19:52:27 + Forwarded from rom: Shyama Pagad s.pa...@auckland.ac.nz on Aliens-L list server Correspondence Nature Vol 475 July 7 2011 -- Non-natives: 141 scientists object We the undersigned feel that in advocating a change in the environmental management of introduced species (Nature 474, 153–154; 2011), Mark Davis and colleagues assail two straw men. First, most conservation biologists and ecologists do not oppose non-native species per se — only those targeted by the Convention on Biological Diversity as threatening “ecosystems, habitats or species”. There is no campaign against all introductions: scarcity of resources forces managers to prioritize according to the impact of troublesome species, as in the Australian Weed Risk Assessment. Second, invasion biologists and managers do not ignore the benefits of introduced species. They recognize that many non-native species curtail erosion and provide food, timber and other services
Re: [ECOLOG-L] Responses to Davis_etal..Nature article on invasive species
How much of that invasion is natural, and how much of it is the barred owl taking advantage of our interference with the forest ecosystem, Warren? It's hard to claim the western forests are wildernesses untouched by the hand of man. Even patches of relatively unchanged forests are affected by our cutting of large expanses of forests in between those patches. Dave On 7/7/2011 1:53 AM, Warren W. Aney wrote: Geoff, mantras such as you cite are good as long as we recognize that they tend to simplify grand complexity. The more or less natural barred owl invasion of spotted owl habitat resulting in population displacement and reduction is a good example of how even natural evolution/change can be seen as adverse. Warren W. Aney Senior Wildlife Ecologist Tigard, Oregon -- -- David M. Lawrence| Home: (804) 559-9786 7471 Brook Way Court | Fax: (804) 559-9787 Mechanicsville, VA 23111 | Email: d...@fuzzo.com USA | http: http://fuzzo.com -- All drains lead to the ocean. -- Gill, Finding Nemo We have met the enemy and he is us. -- Pogo No trespassing 4/17 of a haiku -- Richard Brautigan
Re: [ECOLOG-L] Responses to Davis_etal..Nature article on invasive species
Usually when people talk about invasive species providing balance they are talking about plants. I disagree with that, but please remember most of these articles are generalizing to all invasive species. This is not OK. Then let's take the case of extreme imbalance caused novel predators and browsers which have caused extinctions of naive species within years, or decades. I suggest the balance angle is advocated most by people with a continental biological perspective, island biology is quite different. Sorry to fall back on a single example but it is illustrative of this lack of balance and I see only loss. Have you heard the story about the lighthouse keeper's cat and then cats on Stephen's Island that made an endemic wren and some other species go extinct within 4-6 years? Galbreath, R., and D. Brown. 2004. The tale of the lighthouse-keeper’s cat: discovery and extinction of the Stephens Island wren (Traversia lyalli). Notornis *51*:193-200. The Stephens Island wren Traversia lyalli is widely quoted as having been discovered and promptly exterminated from its only locality, Stephens Island, New Zealand, by a single lighthouse keeper’s cat. Examination of archival and museum records indicates that this account is oversimplified, and throws more light on the roles of the lighthouse keeper David Lyall, the dealer Henry Travers, and the ornithologists Sir Walter Buller and Walter Rothschild. Extinction of the wren was more extended than generally stated: 10 specimens were evidently brought in by a cat in 1894, but another two-four were obtained in 1895, and two-three more after that and possibly as late as 1899. Fifteen of these specimens are still held in museums. Cat predation probably was the main factor in the wren’s extinction, but not necessarily by a single cat: cats became established on Stephens Island in 1894, increased rapidly and exterminated several other species before they were eliminated. This reputed to have been the only flightless passerine (is that true?) Chris Buddenhagen On Thu, Jul 7, 2011 at 5:16 AM, Payal Bal pb...@st-andrews.ac.uk wrote: Such an interesting read! Conservation is all about contradictions. Like any area of research actually..so that's nothing new. But in conservation, more than others, one needs to pick a side and stick to it..at least for a while. It is true about the environment being in a deep dynamic balance. But just because we have defined it as a 'dynamic balance' in our books and conversations doesn't mean it isn't a contradiction too. What if biological invasions are just another way of the ecosystem trying to cope with the environmental changes, of taking an evolutionary step. Only this time the changes aren't natural but brought about by our actions. Of course we must all have realized by now that the next evolutionary stage will not be as biologically diverse as the one before because we have ensured it won't be. So maybe the answer to managing ecosystems now is to allow these changes and carry out re-introductions in new, suitable habitats rather than historical ones. Maybe we can aid in the evolutionary process by letting go of old ecosystem boundaries and animal ranges. On the other hand, one might argue that if we were to all take this view there'll be nothing left but invasives and deserts and mines. But even that we aren't sure of are we? So who is to say what is the right approach. Just because something was a certain way, doesn't make it right does it! Well, even I don't have a stand on this as yet and I'm trying to find it. This is my biggest concern really..what side will I pick. I would like to believe that maybe we will need to allow ecosystems to achieve a new balance but then..I don't know. Cheers, Payal. On 7 July 2011 06:10, Geoffrey Patton gwpatt...@yahoo.com wrote: My wife and I were discussing this topic the other day while hiking through a Maryland park infested with Chinese garlic mustard and Japanese stilt grass (among other invasives). We'd biked past slopes of kudzu and came from Florida's expanses of Brazilian peppers and punk trees. Certainly, we appreciate that Science will note positive aspects in selected situations where there are temporally-beneficial effects. However, the mantra that remains to be overturned is that Any change from the natural evolution of an ecosystem is, by definition, adverse. Ecosystems took millions of years of experimentation to achieve a deep dynamic balance. Upset by out-of-control human intervention can tilt against a healthy balance and remains counter to maintenance of diversity. Cordially yours, Geoff Patton, Ph.D. 2208 Parker Ave., Wheaton, MD 20902 301.221.9536 --- On Wed, 7/6/11, Christopher M Moore cmmo...@unr.edu wrote: From: Christopher M Moore cmmo...@unr.edu Subject: Re: [ECOLOG-L] Responses to Davis_etal..Nature article on invasive species To: ECOLOG-L@LISTSERV.UMD.EDU Date: Wednesday
[ECOLOG-L] Responses to Davis_etal..Nature article on invasive species
Date: Wed, 06 Jul 2011 19:52:27 + Forwarded from rom: Shyama Pagad s.pa...@auckland.ac.nz on Aliens-L list server Correspondence Nature Vol 475 July 7 2011 -- Non-natives: 141 scientists object We the undersigned feel that in advocating a change in the environmental management of introduced species (Nature 474, 153154; 2011), Mark Davis and colleagues assail two straw men. First, most conservation biologists and ecologists do not oppose non-native species per se only those targeted by the Convention on Biological Diversity as threatening ecosystems, habitats or species. There is no campaign against all introductions: scarcity of resources forces managers to prioritize according to the impact of troublesome species, as in the Australian Weed Risk Assessment. Second, invasion biologists and managers do not ignore the benefits of introduced species. They recognize that many non-native species curtail erosion and provide food, timber and other services. Nobody tries to eradicate wheat, for instance. Useful non-native species may sometimes still need to be managed because they have a negative impact, such as tree invasions that cause water loss in the South African fynbos. Davis and colleagues downplay the severe impact of non-native species that may not manifest for decades after their introduction as occurred with the Brazilian pepper shrub (Schinus terebinthifolius) in Florida (J. J. Ewel in Ecology of Biological Invasions of North America and Hawaii (eds H. A. Mooney and J. A. Drake) 214230; Springer, 1986). Also, some species may have only a subtle immediate impact but affect entire ecosystems, for example through their effect on soils. Pronouncing a newly introduced species as harmless can lead to bad decisions about its management. A species added to a plant community that has no evolutionary experience of that organism should be carefully watched. For some introductions, eradication is possible. For example, 27 invasive species have been eradicated from the Galapagos Islands, mitigating severe adverse effects on endemic species. Harmful invasive species have been successfully kept in check by biological, chemical and mechanical means. The public must be vigilant of introductions and continue to support the many successful management efforts. Daniel Simberloff* University of Tennessee, Tennessee, USA. dsimberl...@utk.edu *On behalf of 141 signatories [http://www.nature.com/nature/journal/v475/n7354/extref/475036a-s1.pdfhttp://www.nature.com/nature/journal/v475/n7354/extref/475036a-s1.pdf] (see go.nature.com/f1eqjn). -- Non-natives: put biodiversity at risk Bias against non-native species is not xenophobic (Nature 474, 153154; 2011) it has a sound scientific foundation. The non-native status of a species is highly relevant to assessing its potential environmental and economic impact. Unrestrained growth and environmental damage follow when there are no natural enemies in newly colonized areas. This is not necessarily a sign of an invaders superior evolutionary fitness: it may lead to a population collapse due to overexploitation of resources. Non-native species can increase the variety of species in a community, but it is an oversimplification to equate this with increased biodiversity, of which species richness is only one component. Surviving populations of native species may shrink or become restricted to poor-quality marginal habitats. Such unevenness hardly contributes to a more diverse community. The genetic diversity of invaded communities may decrease because of bottlenecks: native genotypes disappear as populations fall, whereas the invaders originate from very few initial colonizers. Establishment of non-native species inevitably decreases global diversity. Australia, for example, was unique in having no placental mammals; their introduction by humans made the continent ecologically more similar to the rest of the world. Andrei Alyokhin University of Maine, Maine, USA. andrei.alyok...@umit.maine.edu -- Non-natives: plusses of invasion ecology Contrary to the implications of Mark Davis and colleagues (Nature 474, 153154; 2011), invasion ecology has given us valuable insight into the effects of new species on ecological function and into some of the precipitous changes we may face in the coming decades. Invasion ecologists generally assert that only a very small fraction of non-native species harm their new ecosystems. This position emerged as early as 1986 and was mainstream in the era that Davis and colleagues claim as the nadir of ecological nativism. It is unfair to characterize any scientific discipline solely by past failures and to ignore its successes. Invasion ecology is making real progress with defining impact and characterizing risk. Lets not throw up our hands in despair just yet. Julie L. Lockwood Rutgers, The State University of
Re: [ECOLOG-L] Responses to Davis_etal..Nature article on invasive species
Thanks for the post David. As a newcomer to science (working on my Ph.D.), there were some lingering questions I had while reading Davis et al. and the responses: Is this how we want to move forward as a science? What does it mean when we resort to gathering signatures? Is this how our science should work? What does it contribute? How should we deal with issues that are debated in a more productive and less polarizing manner? Personally, I don't think that petitioning changes ecology nor any other natural phenomena. I would like to add Peter Kareiva's blog on the matter to be added to this discussion: http://blog.nature.org/2011/06/invasive-species-fight-mark-davis-peter-kareiva/ Opening of the piece: A famous person once observed that the signature of a civilized mind is the ability to hold two seemingly contradictory ideas in one’s head at the same time. This is exactly what conservation must learn to do when it comes to introduced (or what we often call “non-native” or “invasive”) species. Cheers, Chris On Jul 6, 2011, at 2:18 PM, David Duffy wrote: Date: Wed, 06 Jul 2011 19:52:27 + Forwarded from rom: Shyama Pagad s.pa...@auckland.ac.nz on Aliens-L list server Correspondence Nature Vol 475 July 7 2011 -- Non-natives: 141 scientists object We the undersigned feel that in advocating a change in the environmental management of introduced species (Nature 474, 153–154; 2011), Mark Davis and colleagues assail two straw men. First, most conservation biologists and ecologists do not oppose non-native species per se — only those targeted by the Convention on Biological Diversity as threatening “ecosystems, habitats or species”. There is no campaign against all introductions: scarcity of resources forces managers to prioritize according to the impact of troublesome species, as in the Australian Weed Risk Assessment. Second, invasion biologists and managers do not ignore the benefits of introduced species. They recognize that many non-native species curtail erosion and provide food, timber and other services. Nobody tries to eradicate wheat, for instance. Useful non-native species may sometimes still need to be managed because they have a negative impact, such as tree invasions that cause water loss in the South African fynbos. Davis and colleagues downplay the severe impact of non-native species that may not manifest for decades after their introduction — as occurred with the Brazilian pepper shrub (Schinus terebinthifolius) in Florida (J. J. Ewel in Ecology of Biological Invasions of North America and Hawaii (eds H. A. Mooney and J. A. Drake) 214–230; Springer, 1986). Also, some species may have only a subtle immediate impact but affect entire ecosystems, for example through their effect on soils. Pronouncing a newly introduced species as harmless can lead to bad decisions about its management. A species added to a plant community that has no evolutionary experience of that organism should be carefully watched. For some introductions, eradication is possible. For example, 27 invasive species have been eradicated from the Galapagos Islands, mitigating severe adverse effects on endemic species. Harmful invasive species have been successfully kept in check by biological, chemical and mechanical means. The public must be vigilant of introductions and continue to support the many successful management efforts. Daniel Simberloff* University of Tennessee, Tennessee, USA. dsimberl...@utk.edu *On behalf of 141 signatories [http://www.nature.com/nature/journal/v475/n7354/extref/475036a-s1.pdfhttp://www.nature.com/nature/journal/v475/n7354/extref/475036a-s1.pdf] (see go.nature.com/f1eqjn). -- Non-natives: put biodiversity at risk Bias against non-native species is not xenophobic (Nature 474, 153–154; 2011) — it has a sound scientific foundation. The non-native status of a species is highly relevant to assessing its potential environmental and economic impact. Unrestrained growth and environmental damage follow when there are no natural enemies in newly colonized areas. This is not necessarily a sign of an invader’s superior evolutionary fitness: it may lead to a population collapse due to overexploitation of resources. Non-native species can increase the variety of species in a community, but it is an oversimplification to equate this with increased biodiversity, of which species richness is only one component. Surviving populations of native species may shrink or become restricted to poor-quality marginal habitats. Such unevenness hardly contributes to a more diverse community. The genetic diversity of invaded communities may decrease because of bottlenecks: native genotypes disappear as populations fall, whereas the invaders originate from very few initial colonizers. Establishment of non-native species
Re: [ECOLOG-L] Responses to Davis_etal..Nature article on invasive species
My wife and I were discussing this topic the other day while hiking through a Maryland park infested with Chinese garlic mustard and Japanese stilt grass (among other invasives). We'd biked past slopes of kudzu and came from Florida's expanses of Brazilian peppers and punk trees. Certainly, we appreciate that Science will note positive aspects in selected situations where there are temporally-beneficial effects. However, the mantra that remains to be overturned is that Any change from the natural evolution of an ecosystem is, by definition, adverse. Ecosystems took millions of years of experimentation to achieve a deep dynamic balance. Upset by out-of-control human intervention can tilt against a healthy balance and remains counter to maintenance of diversity. Cordially yours, Geoff Patton, Ph.D. 2208 Parker Ave., Wheaton, MD 20902 301.221.9536 --- On Wed, 7/6/11, Christopher M Moore cmmo...@unr.edu wrote: From: Christopher M Moore cmmo...@unr.edu Subject: Re: [ECOLOG-L] Responses to Davis_etal..Nature article on invasive species To: ECOLOG-L@LISTSERV.UMD.EDU Date: Wednesday, July 6, 2011, 6:30 PM Thanks for the post David. As a newcomer to science (working on my Ph.D.), there were some lingering questions I had while reading Davis et al. and the responses: Is this how we want to move forward as a science? What does it mean when we resort to gathering signatures? Is this how our science should work? What does it contribute? How should we deal with issues that are debated in a more productive and less polarizing manner? Personally, I don't think that petitioning changes ecology nor any other natural phenomena. I would like to add Peter Kareiva's blog on the matter to be added to this discussion: http://blog.nature.org/2011/06/invasive-species-fight-mark-davis-peter-kareiva/ Opening of the piece: A famous person once observed that the signature of a civilized mind is the ability to hold two seemingly contradictory ideas in one’s head at the same time. This is exactly what conservation must learn to do when it comes to introduced (or what we often call “non-native” or “invasive”) species. Cheers, Chris On Jul 6, 2011, at 2:18 PM, David Duffy wrote: Date: Wed, 06 Jul 2011 19:52:27 + Forwarded from rom: Shyama Pagad s.pa...@auckland.ac.nz on Aliens-L list server Correspondence Nature Vol 475 July 7 2011 -- Non-natives: 141 scientists object We the undersigned feel that in advocating a change in the environmental management of introduced species (Nature 474, 153–154; 2011), Mark Davis and colleagues assail two straw men. First, most conservation biologists and ecologists do not oppose non-native species per se — only those targeted by the Convention on Biological Diversity as threatening “ecosystems, habitats or species”. There is no campaign against all introductions: scarcity of resources forces managers to prioritize according to the impact of troublesome species, as in the Australian Weed Risk Assessment. Second, invasion biologists and managers do not ignore the benefits of introduced species. They recognize that many non-native species curtail erosion and provide food, timber and other services. Nobody tries to eradicate wheat, for instance. Useful non-native species may sometimes still need to be managed because they have a negative impact, such as tree invasions that cause water loss in the South African fynbos. Davis and colleagues downplay the severe impact of non-native species that may not manifest for decades after their introduction — as occurred with the Brazilian pepper shrub (Schinus terebinthifolius) in Florida (J. J. Ewel in Ecology of Biological Invasions of North America and Hawaii (eds H. A. Mooney and J. A. Drake) 214–230; Springer, 1986). Also, some species may have only a subtle immediate impact but affect entire ecosystems, for example through their effect on soils. Pronouncing a newly introduced species as harmless can lead to bad decisions about its management. A species added to a plant community that has no evolutionary experience of that organism should be carefully watched. For some introductions, eradication is possible. For example, 27 invasive species have been eradicated from the Galapagos Islands, mitigating severe adverse effects on endemic species. Harmful invasive species have been successfully kept in check by biological, chemical and mechanical means. The public must be vigilant of introductions and continue to support the many successful management efforts. Daniel Simberloff* University of Tennessee, Tennessee, USA. dsimberl...@utk.edu *On behalf of 141 signatories [http://www.nature.com/nature/journal/v475/n7354/extref/475036a-s1.pdfhttp://www.nature.com/nature/journal/v475/n7354/extref/475036a-s1.pdf] (see go.nature.com/f1eqjn). -- Non-natives: put biodiversity at risk Bias
