Re: Invasives
The idea that vacant niches do not exist is basically founded on a strict interpretation of Hutchinson's definition. It is the kind of rigid view that holds back science. Invasive species are successful either because the occupy a vacant niche or because they force closer packing of occupied niches. For example, if you remove all the top predators from a system then lower trophic levels explode, and there is a vacant niche. If you remove wolves, then deer populations grow and you may have to hire hunters to fill the empty niche. I'm not disputing that some introductions are based on fallacious arguments, but invoking the literal word of Hutchinson doesn't contribute much to the discussion. Bill Silvert - Original Message - From: Randy Bangert [EMAIL PROTECTED] To: ECOLOG-L@LISTSERV.UMD.EDU Sent: Wednesday, November 21, 2007 9:54 PM Subject: Re: Invasives It seems to me that these exotic gallinaceous birds were really introduced to have something different to shoot. Using them to occupy vacant niches appears to just be a convenient excuse foisted on us. After-all, are there really vacant niches? One perspective suggests that the niche is defined around the species, so 'vacant' niches do not exist. Another specious triumph for wildlife biology.
Re: ECOSYSTEM HEALTH Diversity and of Terminology Re: Invasives
Ecosystem health is not just weak, but it is undefinable. Either it is circular (what is healthy is natural) or it is multifarious...that is, defined differently in each case in which it used. If it is the former, then diversity is NOT a measure of ecosystem health, since there are so man= y variously diverse and natural ecosystems out there. If it is the latter, then by being anything, it is nothing. We all know what we think we mean by the terms, but we just are unable to measure it beyond merely stating that healthy ecosystems are less perturbed by man. The less perturbed, the healthier. Yet, defining that using ambiguous indices such as diversity, richness and so, does not clarif= y nor help. Cheers, Jim On 11/21/07, Wayne Tyson [EMAIL PROTECTED] wrote: Ecosystem health is a broad term, but are broad terms necessarily invalid or lacking in utility? If it is weak, let us explore the reason why it is so. And, let us find another that is stronger. Is it (whatever term is best) necessarily--or at all--equivalent to greater diversity? Are there ecosystems with lower diversity that are healthy in terms of their persistence, resistance to invasion, and resilience? Is diversity a measure of ecosystem health, or is it more of a measure of its interest to humans? Is it a simple matter of counting the number of niches and species? Is ecosystem (as a well-considered division) composition (species, populations, biomass, distributions, etc.) a reflection of the habitat that supports (or permits) it? I quite agree that more diverse ecosystems might well (as a matter of common sense) have a greater number of invasive species (I wonder how it acquired such diversity), but I simply don't know that it means they are more susceptible to invasions from, shall we say, distant ecosystems? Where does one draw the line between an invader and a shift in species composition due to, shall we say, climate change? WT PS: Is the history of the development of life on earth one of invasion? If not, what? Is beneficial an invalid term? (I confess to having used it.) How might value-free and value-laden apply to this discussion? At 01:48 AM 11/20/2007, William Silvert wrote: With regard to Kelly's first point, Bill (and all): interestingly, it has been proven that ecosystems wit= h a large degree of biodiversity (read: healthy ecosystems) have more varieties of invasives present than those ecosystems that have less biodiversity. I think that the healthy ecosystem argument that was proposed is a wea= k one. Greater diversity means more niches (apologies to the strict Hutchinsonians!) and more opeinings for invaders. Also I suspect that a healthy human body may have more harmful microbes than a sick one, since the sick body will be prone to succumb. Anyway the biomathematicians claim that more complex ecosystems are actually less stable, although the argument is based on unrealistic models. As for the second point, I imagine that almost all organisms began their careers as invaders. Some are beneficial, some are not. Evolution involves not only stronger individuals within a species but also interspecies competition. We are here because mammals successfully invaded dinosaur territory. And while it is sad when we see species go extinct, this matter of some species losing out to others, whether invaders or natives, is a natural process. Bill Silvert PS -- Kelly and others, please use a meaningful subject line, not just the digest name. - Original Message - From: Kelly Stettner [EMAIL PROTECTED] To: ECOLOG-L@LISTSERV.UMD.EDU Sent: Monday, November 19, 2007 6:54 PM Subject: Re: ECOLOG-L Digest - 15 Nov 2007 to 16 Nov 2007 (#2007-310) Bill (and all): interestingly, it has been proven that ecosystems wit= h a large degree of biodiversity (read: healthy ecosystems) have more varieties of invasives present than those ecosystems that have less biodiversity. I can dig up the studies, if anyone is interested. There is always the question of what good do invasive species (particularly plants) do in an ecosystem? Yes, here I go again, playing Devil's Advocate...but consider for a moment how some of these rampant, densely-populated plant colonies effectively fix carbon from the atmosphere, alter the soil chemistry and hence the soil zoology and biology (potentially for the better?), and some even filter toxic chemicals from the soil. For example, Japanese knotweed (Fallopia japonica, Polygonum cuspidatum) appears to thrive in old mines, being quite adept at leaching out copper from the soil. I think that a lot of ecological thought can be turned on its ear by thinking outside one's paradigm, looking at the bigger picture. But Bill is right in that s= o very many people make abolishing invasives their life's work...their sole raison d'etre. Invasive =3D Evil, no ifs, ands
Re: Invasives
If we look at the structure of communities it is easy to see why some have more niches than others. Arctic communities have low diversity because much of the structure that supports biodiversity is absent. Where are the trees and bushes and underbrush that are home to so many species? There isn't even any exposed soil! And there are no niches for organisms prone to freezing, which eliminates most terrestrial bugs and reptiles. Biodiversity reflects structure, and more complex structures offer more niches. Also narrow niches have to be more hospitable than wide ones. Specialised predators have very narrow food niches, but this works OK if there is lots of food available in that niche -- plenty of eucalyptus for koalas and bamboo for pandas. But coyotes in the desert eat whatever comes along, whether prairie dogs, snakes, or insects. Bill Silvert - Original Message - From: Charles Welden [EMAIL PROTECTED] To: ECOLOG-L@LISTSERV.UMD.EDU Sent: Wednesday, November 21, 2007 9:56 PM Subject: Re: Invasives Maybe not directly relevant to the discussion, but I wonder about the = assumption that a more diverse community having more niches than a less = diverse one. It's also conceivable that it might just have more niche = overlap. In other words, the presumed correlation between diversity and = number of niches assumes little or no niche overlap, but there's at least = some evidence that niches do overlap within a community. This connects to = the equilibrium/disequilibrium discussion of community structure = dynamics. I confess a bias toward looking at things as continua rather than as = discrete packets. So I'd rather think about niche space (a la Hutchinson, = plus) and how you pack species in there. You could pack a lot in if they = all had small, non-overlapping niches, or if they all had big, overlapping = niches, or any combination or intermediate. ...just random thoughts... Charles
Pandoras box, was: invasive species and cats
David has opened a line that I was surprised not to see before -- = introduced aliens for biological control of other aliens. Widely = accepted when the control species is a specific disease organism or = parasite (like myximitosis for rabbits and certain wasps), but usually = subject to the law of unintended consequences. Bill Silvert - Original Message -=20 From: David Hilmy=20 To: [EMAIL PROTECTED] Cc: 'William Silvert'=20 Sent: Thursday, November 22, 2007 2:11 PM Subject: RE: invasive species and cats (Bill Silvert) And if you will forgive me Bill, but perhaps one way of dealing with = the invasive arrow bamboo, Pseudosasa japonica, would be to perhaps = introduce one of it's feared enemies, the Giant Panda (apparently arrow = bamboo is favored by both Mei Xiang and Tian Tian here in DC) and as it = has been documented that pandas in the wild are known to feed on 42 = species of bamboo [Taylor AH, Qin Z. 1993. Ageing Bamboo Culms to Assess = Bamboo Population Dynamics in Panda Habitat. Env Cons 20:76-79], other = problem species may also suffer the same fate. Although we will all have = heard of the trouble we can get into when we introduce the alien = predator to the alien target species and find that they end up targeting = everything native as well (the concept of alternative prey abundance = supporting predators came a little too late for some); and what of that = American Dream, KFN: Kentucky Fried Nutria, a 12-pound water rat that = culinary experts say tastes somewhat like a beaver, is less greasy than = a 'coon but is not quite as good as possum? [Grimes, D. Sarasota = Herald-Tribune, 1997] =20 David =20 David Hilmy Director of Conservation KuTunza Environmental Education Program Europe: 27 avenue de l'Op=E9ra, 75001 Paris, France USA: 2804 Shepherd St., Mount Rainier, MD 20712; 202-316-4902 =20 =20 =20 -Original Message- From: William Silvert [mailto:[EMAIL PROTECTED] Sent: Wednesday, November 21, 2007 4:40 PM Subject: Re: invasive species and cats =20 Unfortunately the real issue is not whether a species is invasive but=20 whether it is charismatic. Cats, mustangs, and even panda bears if = they were=20 released into the wild and could survive in N. America, are = charismatic.=20 Whether they fit into the ecosystem is politically irrelevant. =20 Birds of course are also charismatic, but I think that cats trump = piping=20 plovers. =20 Bill Silvert =20 =20 - Original Message -=20 From: Blanc, Lori [EMAIL PROTECTED] To: ECOLOG-L@LISTSERV.UMD.EDU Sent: Tuesday, November 20, 2007 8:29 PM Subject: invasive species and cats =20 =20 In all the discussion so far about introduced/invasive/non-native species, I don't recall seeing any mention of cats. =20 I've heard a lot about the impacts of cats on wildlife in Australia, = but not as much about cats here in the U.S. Indeed - this can be a sensitive issue, since so many people have cats for pets, and let = the cats have free roam outside. For example, I recently saw an article = in the New York Times (Nov 13), which presented the case of a birder in Texas who shot a feral cat, which he had observed stalking = endangered piping plovers. This case is in court, with many people upset about = the cruel treatment (i.e. shooting) of the cat. The person who shot the = cat faces up to 2 years in prison and a $10,000 fine for shooting the = cat. =20 So, this raises a few questions: =20 1) Are house cats considered an invasive species in North America? 2) Do cats have a significant negative impact on avian populations = in North America? =20 I realize that I can do a quick literature search on this topic to = learn more, but I'm also curious to see what the general opinions are of = the ecologists on this listserv, especially within the context of the = recent invasive species discussion. =20 Thanks, =20 Lori=20
Re: textbook-free classes
Bill Silvert underscores a point I was trying to make in my original post. Humans are not only a part of the ecosystem; they have become one of the dominant ecologicaland geological forces on the planet. My own approach to this has been to insert humanity into the picture as case studies to illustrate mainstream ecological themes. Examples: Talking about Biogeochemical cycling - Introduce a section on cultural eutrophication and Lake Winnipeg. Talking about different population growth models - lets apply that to the human population and discuss issues of carying capacity. Of course, my class is supposed to be a SCIENCE class, and talking about Hamanity's role in the biosphere could threaten to bring out passionate views. But I am careful throughout to emphasize that if we want to solve environmental problems, understanding their biophysical basis is essential as a precursor to policy. One or two other posts to this thread separated out environmental and ecological science. I do not think such a separation is real. When we are talking about environmental science, we are talking about aspects of ecology. And there is another thing: we appear to be at a critical juncture in history. We are in the process of altering fundamental aspects of the biosphere. Numerous environmental problems (climate change, overfishing, soil erosion, peak oil, invasives etc) are reaching critical junctures. Yet ( and I challenge teachers to probe student awareness of these issues) a majority of students are only vaguely aware of these problems. For this reason, I am continually thinking about ways to overhaul my teaching to keep the fundamentals but also teach about our new and unfortunate reality. Cheers, Andy Park (University of Winnipeg) Quoting William Silvert [EMAIL PROTECTED]: I agree with Jeff's view that if an instructor also writes the textbook, the students get a pretty narrow view of the field. There has to be an alternative vision. I know one university where the entire department is collaborating on a textbook, and that is a possible solution -- diversity of viewpoints, consistent with department policy, and affordable. One point that has not come up is the scope of what we call ecology. I attend a lot of international workshops and at the level where ecologists are involved in policy issues it is clear that humans are port of the ecosystem. To what extent is this taught? I think that if we compare this discussion of textbooks with the parallel discussion of invasives we see that trying to discuss any ecological issue without taking into account human values as well as human intervention can be pretty futile. Bill Silvert - Original Message - From: Jeff Jewett [EMAIL PROTECTED] To: ECOLOG-L@LISTSERV.UMD.EDU Sent: Tuesday, November 20, 2007 10:11 PM Subject: textbook-free classes I have always had a problem, however, with instructors whose only reading material is something that they wrote themselves (whether it was a coursepack or something more formal). Every student learns differently, and not all students will relate well to any particular instructor's teaching style.
Re: invasive species and cats
Hi All, I'm a cat lover myself, but because I love my cat, It is an indoor cat, no fleas, ticks, cars, strange foods, I love my cat. People who have outdoor cats, unless say on a farm where they are working animals for rodent abatement, don't really have a pet they love, they are just owning an animal that is low maintenance. They love the low maintenance. I've weighed this a great deal with cat people for many many years. I don't believe you can love a pet if you are not responsible about your relationship with it. Cats are feral as soon as they hit your door to the outside, feral cats are a very serious threat to wildlife. Will, with an Opinion! On 11/21/07, Warren W. Aney [EMAIL PROTECTED] wrote: Yes, feral cats are considered an unwelcome invasive. Just ask any field biologist or the Audubon Society http://www.audubon.org/local/cn/98march/nasr.html Warren W. Aney Senior Wildlife Ecologist Tigard, OR 97223 -Original Message- From: Ecological Society of America: grants, jobs, news [mailto:[EMAIL PROTECTED] Behalf Of Blanc, Lori Sent: Tuesday, November 20, 2007 12:30 PM To: ECOLOG-L@LISTSERV.UMD.EDU Subject: invasive species and cats Hi all -- In all the discussion so far about introduced/invasive/non-native species, I don't recall seeing any mention of cats. I've heard a lot about the impacts of cats on wildlife in Australia, but not as much about cats here in the U.S. Indeed - this can be a sensitive issue, since so many people have cats for pets, and let the cats have free roam outside. For example, I recently saw an article in the New York Times (Nov 13), which presented the case of a birder in Texas who shot a feral cat, which he had observed stalking endangered piping plovers. This case is in court, with many people upset about the cruel treatment (i.e. shooting) of the cat. The person who shot the cat faces up to 2 years in prison and a $10,000 fine for shooting the cat. So, this raises a few questions: 1) Are house cats considered an invasive species in North America? 2) Do cats have a significant negative impact on avian populations in North America? I realize that I can do a quick literature search on this topic to learn more, but I'm also curious to see what the general opinions are of the ecologists on this listserv, especially within the context of the recent invasive species discussion. Thanks, Lori ~~~ Lori Blanc, Ph.D. Dept. of Biological Sciences Virginia Polytechnic Institute State University 540-231-5256
Re: Invasives
Of course the introducers of gallinaceous game birds were primarily interested in providing something to shoot, but in their view the system was deficient in species and this suggested an opportunity. Some mistakes were made in the process. So we have catchable eastern warmwater fish species (bass, sunfish, bullheads, walleye) crowding out less catchable/tasty native species. Then we have the well-intentioned effort to improve wildlife habitat in the semiarid Columbia Basin Plateau -- black locust and Russian olive were the species of choice since the region didn't seem to have suitable native upland trees -- a vacant niche. The Russian olive can reproduce in its own shade, its dense thickets have taken over a lot of meadow and riparian areas and it is now considered a weedy invasive. So I'm thinking, as Bill suggests, that we can hold either a rigid view that all manipulation of natural systems is bad, or the equally rigid view that anything we can do to improve systems for our benefit is good. There is a middle ground. Warren W. Aney Tigard, Oregon -Original Message- From: Ecological Society of America: grants, jobs, news [mailto:[EMAIL PROTECTED] Behalf Of William Silvert Sent: Thursday, November 22, 2007 2:04 AM To: ECOLOG-L@LISTSERV.UMD.EDU Subject: Re: Invasives The idea that vacant niches do not exist is basically founded on a strict interpretation of Hutchinson's definition. It is the kind of rigid view that holds back science. Invasive species are successful either because the occupy a vacant niche or because they force closer packing of occupied niches. For example, if you remove all the top predators from a system then lower trophic levels explode, and there is a vacant niche. If you remove wolves, then deer populations grow and you may have to hire hunters to fill the empty niche. I'm not disputing that some introductions are based on fallacious arguments, but invoking the literal word of Hutchinson doesn't contribute much to the discussion. Bill Silvert - Original Message - From: Randy Bangert [EMAIL PROTECTED] To: ECOLOG-L@LISTSERV.UMD.EDU Sent: Wednesday, November 21, 2007 9:54 PM Subject: Re: Invasives It seems to me that these exotic gallinaceous birds were really introduced to have something different to shoot. Using them to occupy vacant niches appears to just be a convenient excuse foisted on us. After-all, are there really vacant niches? One perspective suggests that the niche is defined around the species, so 'vacant' niches do not exist. Another specious triumph for wildlife biology.
Announcing the IAVS Vegetation Forum
The International Association for Vegetation Science (IAVS) has established a new email discussion group: the IAVS Vegetation Forum. The purpose of the Forum is to provide a convenient venue for announcements or discussion of topics of interest to vegetation scientists. Individuals wishing to join the list may do so at any time at http://lists.unc.edu/read/all_forums/subscribe?name=iavs%20 Please feel encouraged to spread the word. This listserv is open to anyone with an interest in vegetation science. If you have any questions or problems, please send an email to [EMAIL PROTECTED] Robert K. Peet President, International Association for Vegetation Science == Robert K. Peet, Professor Chair Phone: 919-962-6942 Curriculum in Ecology, CB#3275Fax:919-962-6930 University of North Carolina Cell: 919-368-4971 Chapel Hill, NC 27599-3275 USA Email: [EMAIL PROTECTED] http://www.unc.edu/depts/ecology/ http://www.bio.unc.edu/faculty/peet/ ==
a European perspective on feral cats
Hello from Austria, In Austria, hunters are allowed to shoot stray cats (ca. 300 m - distance from house). But I have also heard stories of hunters shooting cats just so. In a small village, one could suppose that hunters know the owners of the cats, but they will still be shot. It seems that hunters see cats as rivals. I have heard of stories about hunters shooting pet-cats within the allowed range. In central Europe the wild cat is on the Red List.. I have also heard that the Lynx is shot illegally by hunters (and their GPS-collars /transmitters discarded). Below is a brief report from a colleague in Switzerland: Years ago I have been collecting data about alpine reptiles and causes of death. There wasn't a single species of snakes not killed by feral cats. It was only up to the geographic area what species was more often killed. Even Elaphe longissima and Coluber viridiflavus up to 140cm have been killed and adult specimen of Vipera berus and Vipera aspis as well as Natrix natrix and Natrix tesselata. Most often Anguis fragilis was a victim but any species of lizards else too. It is true that most cases of death have been recorded from traffic and agricultural activities but it has to be accepted that feral cats are an important factor of elimination of Reptiles even this might be local, but reptiles also are occurring only locally. Additionally, I have collected data about feral cats killing other wild mammals and birds as well feral stock. The size was going up to Turkey and kitten of feral Goat. Dr. Werner Haberl Former Chair, Insectivore Specialist Group, IUCN Hamburgerstrasse 11/17 A-1050 Vienna, Austria Phone Fax: (+431) 941 13 13 E-Mail: [EMAIL PROTECTED] The Shrew Shrine: http://members.vienna.at/shrew or new: http://members.chello.at/natura The Dormouse Hollow: http://www.glirarium.org/dormouse
Re: [SPAM] textbook-free classes
** Low Priority ** Also, instructional methods don't mean so much at higher levels. At the graduate level especially, students are adults and should be able to develop the necessary understanding in any environment. We are all going to approach each discipline differently. While I can see, and I do, sticking to the textbook more with freshman undergraduate students, and have used textbooks as principle sources in graduate courses, if all a student comes back at me with in a graduate course is what is in some textbook, I would not consider that effort a passing effort at the graduate level. I make it a point to give graduate students questions of a sort they have not seen in class, but require the use of the principles learned during the course when creating tests. A student who cannot handle this is not adequately prepared for graduate level education, and is most certainly not qualified to be awarded a graduate degree. Real science doesn't come with a textbook! So easy it seemed once found, which yet unfound most would have thought impossible John Milton Robert G. Hamilton Department of Biological Sciences Mississippi College P.O. Box 4045 200 South Capitol Street Clinton, MS 39058 Phone: (601) 925-3872 FAX (601) 925-3978 Jeff Jewett [EMAIL PROTECTED] 11/20/07 4:11 PM Speaking as a former high school teacher and current environmental science graduate student, I'd like to comment on instructors tossing the textbook from their courses. I appreciate _supplements_ to the textbook, such as selected websites, journal articles, etc. I have always had a problem, however, with instructors whose only reading material is something that they wrote themselves (whether it was a coursepack or something more formal). Every student learns differently, and not all students will relate well to any particular instructor's teaching style. If the course follows a decent textbook (even if assigned readings are not required), then a motivated student has a fall-back instructional method if lectures are not working (read the book!). If the only reading available is something that the instructor wrote, it is usually more of the same that the student heard in lecture. An instructor-written textbook rarely sheds new light on the subject or teaches with a different explanation of the concept. So...course readers and other supplemental materials are good, but be very careful that students have the opportunity to hear from a variety of instructional voices, not just one. Thanks for listening, Jeff Jewett Montana State University
Re: invasive species and cats
David Hilmy wrote: perhaps one way of dealing with the invasive arrow bamboo, Pseudosasa japonica, would be to perhaps introduce one of it's feared enemies, the Giant Panda (apparently arrow bamboo is favored by both Mei Xiang and Tian Tian here in DC) Sorry David, but your example here reminded me of a conversation I had many years ago with one of my cousins. He said he had the perfect solution to the brown snake problem in Hawaii: pigs. He said Pigs will take care of any snake problem in a hurry! I said, Hawaii already has pigs and they're tearing down the mountainsides. So he said, The solution to that, then, is alligators. They'll take care of any pig problem in a hurry! I said, So your solution is to make Hawaii look just like Florida? (we didn't get into the details of how an aquatic alligator was supposed to take care of a terrestrial pig which was supposed to take care of an arboreal snake...) CL Please note my new-old email address: [EMAIL PROTECTED] ~~ Cara Lin Bridgman P.O. Box 013 Phone: 886-4-2632-5484 Longjing Sinjhuang Taichung County 434 Taiwanhttp://megaview.com.tw/~caralin/ ~~
Another picture
Dear Ecologgers, With all do respect, I disagree with Andy's view that there is no separation between environmental and ecological science. I'm frustrated cause, unfortunately in my country, Turkey, Environmental science = environmental engineering-agricultural engineering-forest engineering = Ecology! And they seem liked to be so called ecologist and even believed they are. The danger is they give lectures about ecology even they do not perform any ecological research in their life. So, When they are talking about environmental science, generally they are not talking about aspects of ecology as he mentioned. With this defective situation you figure out the students' perception of ecology as a science, not mentioning basic principles of ecology. So here both sciences are misrepresented somehow. Of course, we have rare 'silent' ecologists and emerging ones that they grown. Still, ecology is minor science and few eminent universities hesitate to give us a graduate degree on the ecology. Nowadays, as being attempting to teach current ecological issues and their interconnectedness with the social sciences for non-biology majors, I start with the definition and separation of these sciences as emphasizing interactions with each others and the others sciences as well. Here two different definitions for environmental science: The http://www.wordwebonline.com/en/BRANCH branch of http://www.wordwebonline.com/en/BIOLOGY biology http://www.wordwebonline.com/en/CONCERNED concerned with the http://www.wordwebonline.com/en/RELATIONS relations between http://www.wordwebonline.com/en/ORGANISM organisms and their http://www.wordwebonline.com/en/ENVIRONMENT environment - syn: http://www.wordwebonline.com/en/ECOLOGY ecology, http://www.wordwebonline.com/en/BIONOMICS bionomics The science which studies the interaction between man and the environment, emphasizing the links between different subjects related to this issue, including ecology http://www.allwords.com/?SearchType=3Keyword=ecology , economics http://www.allwords.com/?SearchType=3Keyword=economics , geography http://www.allwords.com/?SearchType=3Keyword=geography , geology http://www.allwords.com/?SearchType=3Keyword=geology , meteorology http://www.allwords.com/?SearchType=3Keyword=meteorology , politics http://www.allwords.com/?SearchType=3Keyword=politics and sociology http://www.allwords.com/?SearchType=3Keyword=sociology . After I saw the first definition, I found myself asking what the definition Ecology then was!!! Second one seems quite fair to me. I know that the definition of environmental sciences is broad, overlapping the natural sciences, the social sciences, and engineering. But I really do separate out environmental and ecological science: Environmental science and Ecology are different fields of study, although there is some overlap due to the multidisciplinary nature of environmental science. Ecology is the study of the interrelations of living organisms and their environment, whether at the population, community, or ecosystem level. In contrast, environmental science is a broad area of study including diverse areas such as atmospheric sciences, soil chemistry, pollution-toxicology (water/air/soil quality), environmental law/economics/politics and biological responses of systems to anthropogenic influence. I sum up this subject with the comment of few scientists from The American Institute of Biological Sciences, (AIBS) ' Comments on Draft Taxonomy of Life Sciences, 2003: Another issue we request the Committee reconsider is the association of Ecology and Environmental Science. There is a common public misconception that all ecological research is also environmental research. While there is certainly a strong link between the two disciplines, they are unique. Environmental science has historically been a discipline that includes non-biological sciences and is focused on solving environmental problems. In short, environmental science is largely an interdisciplinary applied science. While ecology has also grown and benefited from increased interdisciplinary collaboration, it is largely a basic science. While what is learned from ecological research can and should inform environmental science and policy, ecology is not by definition an environmental science as environmental science is generally defined. We request the Committee reconsider its linkage of Ecology with Environmental Science. Each discipline is robust enough to warrant consideration as an independent discipline with subfields. I'll appreciate your thoughts. Respectfully, Yasemin Erguner Baytok, PhD candidate
Re: unoccupied niches and 'coppetitive exclusion
The concept of =93niche=94 is very much defined around a specific = species- the term itself is something of a misnomer in ecological terms because we = assume the traditional noun to describe a physical space or an element of = habitat, or in the argument of some posted here, a set of habitat/ecosystem/geographical parameters that are independent of the species itself as though somehow =93vacant=94, yet the term as I have = always understood it to be refers more accurately to the way in which a = particular organism fits into the ecosystem- the evolutionary adaptations that the organism (not the space) has acquired in terms of behavior, morphology, physiology, etc. And so no two species can indeed share the exact same niche, and even if two species shared almost identical ecological = features, the principle of competitive exclusion would apply- in the case of = invasive aliens, quite often =93generalists=94, the advantage in terms of feeding = and then reproducing is taken by the interloper. The term =93niche=94 is = therefore better described as =93functional niche=94 (as in the early work of = Elton and Gause, ca.1935.) =20 I believe it was Charlie, sometime around 1859, who wrote: How strange = it is that a bird, under the form of a woodpecker, should have been created = to prey on insects on the ground; that upland geese, which never or rarely swim, should have been created with webbed feet; that a thrush should = have been created to dive and feed on sub-aquatic insects; and that a petrel should have been created with habits and structure fitting it for the = life of an auk or grebe! and so on in endless other cases. But on the view of each species constantly trying to increase in number, with natural = selection always ready to adapt the slowly varying descendants of each to any unoccupied or ill-occupied place in nature, these facts cease to be = strange, or perhaps might even have been anticipated. =20 =20 David =20 David Hilmy Director of Conservation KuTunza Environmental Education Program Europe: 27 avenue de l'Op=E9ra, 75001 Paris, France USA: 2804 Shepherd St., Mount Rainier, MD 20712; 202-316-4902 =20 =20 =20 -Original Message- From: Randy Bangert [mailto:[EMAIL PROTECTED] Sent: Wednesday, November 21, 2007 4:54 PM Subject: Re: Invasives =20 It seems to me that these exotic gallinaceous birds were really =20 introduced to have something different to shoot. Using them to occupy =20 vacant niches appears to just be a convenient excuse foisted on us. =20 After-all, are there really vacant niches? One perspective suggests =20 that the niche is defined around the species, so 'vacant' niches do =20 not exist. Another specious triumph for wildlife biology. =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D RK Bangert =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D= =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D =20 On Nov 21, 2007, at 12:23 PM, Warren W. Aney wrote: =20 Decades ago there was discussion (and action) regarding the concept of unoccupied niches -- a natural system would have a variety of =20 niches that species could occupy and function in. If there was an unoccupied =20 niche, than a species could be deliberately brought in to fill that niche to benefit an entire system. Some examples: ring-necked pheasants and Hungarian partridge introduced to fill unoccupied niches created by agricultural development. Chukar partridge brought in to occupy =20 niches created by spread of cheatgrass and extirpation of native =20 gallinules. Wild turkey brought in to occupy woodland niches presumably unoccupied =20 or not fully utilized by native grouse. =20 Granted, much of this was done under a rather naive understanding of ecosystem dynamics. Some might consider wild turkey outside its =20 historic range an invasive species, and some such introductions may now seem =20 unwise in retrospect. =20 This also seems to tie to Kelly's comments about biodiversity -- a =20 very diverse ecosystem would have many more niches than a simpler =20 ecosystem. This could suggest that a diverse ecosystem might provide =20 opportunities for invasive species without penalizing native species. However, I =20 think we can find way too many examples of invasives displacing rather than =20 supplementing native species. For example, take a look at what I call the dirty =20 dozen of Oregon invasives that have taken over or are taking over native-=20 occupied niches: =20 European starling -- competing with and replacing native passerines European rock dove (pigeons) -- replacing native columbids Herb robert -- replacing native ground covers in otherwise undisturbed Columbia River Gorge forests Knotweed (more than one species/subspecies) -- invading and =20 simplifying riparian corridors
