Re: [ECOLOG-L] Mosquitoes as keystone species?
Hello Conor, Thank you for sharing these observations. Unfortunately, these are not simple questions to answer, as it would take a prolonged and rigorous discourse on many of the disciplines of ecology to address all the issues. I don't know what chemical your county uses for mosquito control but probably it is not specific to mosquitoes and would affect other insects just as strongly. Fewer bees probably does equate with fewer flowering plants. Are mosquitoes ecologically important? In some places it is a resounding yes -- for example, in places where malaria is abundant, mosquitoes as the primary vector for malaria were a major control on human populations (i.e., mosquitoes promoted a high death rate). Are they a key stone in your community? Probably not, but if you lump them with the rest of the insects that are locally scarce due to pesticides, you could reasonably expect a significant ecological response. For example, the birds and bats which rely on insects for food are likely to be affected. But, on the other hand, mosquitoes are a primary vector for West Nile Virus and WNV kills many species of birds -- hence, eliminating mosquitoes could be a benefit to the bird community. Hopefully you see my point -- the interactions that go on in a situation such as this are hugely complex and dynamic, so its tough to give a simple yes/no kind of answer. I realize I've probably frustrated you more than helped, but that's kind of the way ecology goes (in my opinion). Keep up with the good observations, and let your local community know what you are seeing (i.e., a letter to the editor of your local paper). I bet you'll find more people than just yourself care. Michael Cooperman Post-doctoral Fellow of the National Research Council in residence at NOAA-Fisheries, NE Fisheries Science Center. Conor Flynn wrote: Our field crew is working in the extensive wetlands surrounding Alamosa, CO and we've noticed something interesting: there are no mosquitoes in or near Alamosa. This is because the city sprays for them regularly. We're not complaining... but we have also noticed fewer grasshoppers, bees, and frogs than we might otherwise expect. Are these (and other) species directly affected by the insecticide (which chemicals are used post-DDT?) and/or are mosquitoes ecologically important -- even keystone -- species? What happens when you remove a parasite from the foodweb? Our field crew is, among other things, cataloging the vegetation in the area -- could we expect to see e.g. fewer flowering plants? Anything else we could look for? Is anyone doing research on this quasi-Silent Spring phenomenon or know more about the possible ramifications of parasite/pest control?
Re: [ECOLOG-L] Constrained NMDS?
Hello Dr. Souza, I have not done a constrained NMDS as you ask, but I have used NMDS in the program PC-Ord (developed by McCune) quite a bit. My standard approach is to use 2 data matrices -- the 1st is the community data, and you use this to create the ordination solution (i.e., the distribution of points in space). The 2nd matrix is the environmental data, and you use his to create overlays onto the community ordination (i.e., either generate vectors or scale the size of ordination symbols to an environmental value). In this way, you gain the benefit of the best possible solution of the community data (i.e., the solution is not constrained by the data of the 2nd matrix) and then you get to visualize the relationship with the "controlling variables" of the 2nd matrix). My apologies if you already knew this, as I know it isn't the question you asked. But, maybe it was helpful.... Michael Cooperman Research fellow of the National Research Council Alexandre F. Souza wrote: Hello All, Do anyone has ever performed a constrained NMDS with community data? I have read in McCune and Graces' Analysis of Ecological Communities that the theory of such analysis already exists (i.e., associating vectors of environmental variables to a NMDS ordination) but has seldon been used by ecologists. It would be a better alternative to CCA, which has stingent premises that ecological data does not match properly most of times. I suppose that this could be implemented in R, but I could not find it in Vegan or other packages. Thanks in advance, Alexandre Dr. Alexandre F. Souza Programa de Pós-Graduação em Biologia: Diversidade e Manejo da Vida Silvestre Universidade do Vale do Rio dos Sinos (UNISINOS) Av. UNISINOS 950 - C.P. 275, São Leopoldo 93022-000, RS - Brasil Telefone: (051)3590-8477 ramal 1263 Skype: alexfadigas afso...@unisinos.br http://www.unisinos.br/laboratorios/lecopop
Re: [ECOLOG-L] Fuzzy Set Ordination for classifying plant species ??
Hello Dragos, Sounds like you already have your strategy planned out, but just in case you are looking for an alternative I suggest you look into MRPP (multi-response permutation procedures). Basically, MRPP is a multivariate clustering program and the results of the analysis can then be used to illustrate community structure and relationship to other measured variables (i.e., as an overlay with joint plot on top of a NMS ordination). You can then follow with an indicator species analysis to determine which species (if any) represent groups of lakes. I use the program PC-ORD, which was developed by plant community ecologists to address exactly the types of question you are working with and I think it would serve you well. (PS - I have no financial stake in PC-ORD, just a happy user). Good Luck, Michael Michael Cooperman, PhD National Research Council - Research Fellow in residence at NOAA-Fisheries, NE Fisheries Science Center - Maine Field Station Dragos Zaharescu wrote: I thank Dr. Dan Mckenzie, Dr. Francisco Di Castro and Dr. Mike Hillstrom for their suggestings. Also thanks Dr. Zuur for previous help. They were all useful and helped making a more clear idea how to treat the binary plant data. I also followed the steps for FSO calculation recommended by Dr. Rick Boyce in FSO webpage. I liked it very much and helped it till one point. My original question was simple: One matrix with 170 riparian plant species (columns) and 300 lakes (cases). All, binary variables (presence/absence). I want to know how lakes group together based on their similarities, make a categorical variable representing those groups, and then plot the plants on those groups (categories from cat. var) to see, for ex, plants (plant list) associated to a particular lakes group. I turned back again at the very beginning with this analysis. What I will try now is 1. performing UPGMA cluster analysis using Sorensen similarity index (from FSO webpage) to infer lakes groups and make a categorical variable (in R). 2. Use this cat. variable to associate plant species to those categories. Most probably I will transform the raw variables using Hellinger transformation (from Legendre and Gallager, 2001: Ecologically meaningful transformations for ordination of species data) (in R) and use Fisher´s classification coefficients from a discriminant function Analysis (in SPSS) to associate plants to lakes categories. I am quite new in R but try the best to learn quick. Following the steps from FSO webpage I find no problem in computing Sorensen matrix (must thank Dr. Boyce once again for leave it clear and simple) but no way I can draw UPGMA clustrer analysis on that matrix. Is anyone aware of a routine that can combine both, Sorensen and UPGMA cluster. Unfortunately, my patching did not work. Many thanks to all that helped once again. Dragos Dragos Zaharescu Animal Anatomy Laboratory Faculty of Biological Sciences Vigo University, apd. 137 36310, Vigo (Pontevedra), SPAIN zaha_dra...@yahoo.com zdra...@uvigo.es http://webs.uvigo.es/zdragos/ ~ You should be the change you want to see in the world ~ Ghandi From: Richard L. Boyce To: ECOLOG-L@LISTSERV.UMD.EDU Sent: Wednesday, August 19, 2009 2:26:01 PM Subject: Re: [ECOLOG-L] Fuzzy Set Ordination for classifying plant species ?? It's a little hard to tell from you description what exactly is the problem. I suggest you visit my FSO web page at <http://www.nku.edu/~boycer/fso/> and see if the examples there are helpful. =0A=A0=0AHello,=0A=A0=0AI have a matrix with 180 plant species (variables, = binary) and 270 rows (altitude waterbodies). There is also one categorical = variable (4 categories representing similar lakes groups, which resulted fr= om a prior analysis of the transposed matrix).=0AIs there any way to load p= lant species on those categories in fuzzy-set-ordination analysis? Is there= anyone here that has faced this question before or could provide a hint? A= ll my efforts so far=A0=A0have lead to loading the lakes on the categories = (fso in R); but I want to load the plant species.=0A=A0=0AI would greatly a= ppreciate your help.=0A=A0=0ADragos Zaharescu=0AVigo University=0A=0A~ You = should be the change you want to see in the world=A0~ Ghandi=0A=0A=0A
Re: [ECOLOG-L] Circular data
Hello Jim et al. Recently I had the same problem. I used a trial version of the program Oriana, a stats package specific for circular data. You can get a 1 month free trial on-line at their web page. Very easy to use, I was very happy (I have no financial stake in the program...). Michael Cooperman Jim Rentch wrote: I want to graph circular data, and to compare mean direction of tree-fall and slope aspect. I am using SAS code to generate means (Rayleigh and Watson tests), but I am unable to graph without purchasing a special graphics package. Does anyone know how to graph circular data using Excel? Jim Rentch Assistant Research Professor Division of Forestry and Natural Resources West Virginia University Morgantown, WV 26506-6125 344 Percival Hall Telephone: 304-293-6466 Fax: 304-293-2441 http://community.wvu.edu/~jsr008/
[ECOLOG-L] to Capitalize or not to capitalize
In the following statement: the Narraguagus and Penobscot riversshould the word "rivers" be capitalized? I have my opinion, but in the spirit of not biasing responses I'll keep it to myself; my office as a whole is split 50/50. One way or the other, half the people in my office are wrong! Michael -- --------- Michael Cooperman, PhD National Research Council - Research Fellow in residence at NOAA-Fisheries, NE Fisheries Science Center - Maine Field Station Atlantic Salmon Research and Conservation Task 17 Godfrey DR., Suite 1 Orono, ME 04473 (work) 207-866-7409 (cell) 207-974-9846 (fax) 207-866-7342 (pls call before faxing) email: michael.cooper...@noaa.gov -
[ECOLOG-L] to Capitalize or not to capitalize -- summary of responses
Dear Ecologgers - Thank you very much to everyone that took the time to respond to my original post. I never expected to generate this much discussion. Below is a summary of responses. As a reminder, my original question was, "In the statement, the Narraguagaus and Penobscot rivers." is the word "rivers" capitalized or not? Based on the 31 different responses, it sure seems that the issue is not as cut and dried as I had originally thought. Of the 31 responses, 13 said do NOT capitalize, 7 said YES capitalize, 1 said it didn't matter, 1 said it was context specific, and the rest did not answer the question and just threw out miscellaneous stuff on capitalization styles (i.e., up vs down writing). I was greatly surprised (and delighted) that only 1 person gave a "snarky" response, and I ultimately got an apology from this person through a personal follow up email. For the 3 cases where a respondent specifically cited a style manual, I have pasted their response below (2 = capitalize, 1 do not capitalize). Clearly, this is not a settled issue, and my belief that I was "supremely confident" I knew the correct answer (do not capitalize) has been shattered. Cheers, Michael Cooperman, Post-Doctoral Research Fellow of the National Research Council. __ From http://frwebgate.access.gpo.gov/cgi-bin/getdoc.cgi?dbname=2008_style_manual&docid=f:chapter3.pdf <http://frwebgate.access.gpo.gov/cgi-bin/getdoc.cgi?dbname=2008_style_manual&docid=f:chapter3.pdf> (The GPO Style Manual is intended to facilitate Government printing.) 3.8. The plural form of a common noun capitalized as part of a proper name is also capitalized. Seventh and I Streets Lakes Erie and Ontario Potomac and James Rivers State and Treasury Departments British, French, and United States Governments Presidents Washington and Adams ___ With regard to topographical names, the University of Chicago Press (Manual of Style) recommends that when a generic term is used in the plural either before or after more than one proper name, the term should be capitalized if, in the singular form and in the same position, it would be recognized as a part of each name. Formerly such plural terms were capitalized only when preceding the proper names, Lakes Erie and Huron Mounts Everest and Rainier the Adirondack and Catskill Mountains the Hudson and Mississippi Rivers BUT the rivers Hudson and Mississippi __ I would defer to the Council of Science Editors manual: Scientific Style and Format. According to my 6th edition (there is one more recent), they recommend not capitalizing rivers in your situation... "In a plural construction, lowercase may be used for the generic noun that would be capitalized in the singular unless the common noun precedes a group of proper nouns. Vancouver and Saltspring islandsLakes Ontario and Huron"
[ECOLOG-L] AIC, data-dredging, and inappropriate stats
Hello, I would like to offer one comment to this excellent thread on AIC... Dave Hewitt wrote, "Mixing inferential paradigms is poor, and I don't think we need shrines, scripture, or dogma in this discussion. For one, a direct comparison of correct analyses from the two paradigms can lead to different conclusions (I've seen it). How then can any theory support putting them together? Often an author does this because they show the same story, which is "analysis dredging." If you show both and they disagree, and you don't choose one, there is no theory to guide you to a proper conclusion (of course, the data may not be sufficient to provide such)." If I'm following Dave's thread correct, I disagree with him that "no theory supports putting them together." Indeed, if 2 different measures of fit (i.e., delta AIC value and r^2) support different conclusions, it would be wrong (i.e., disingenuous) to withhold one value. I think you need to provide both and either present an argument why one is better than the other or indicate the this means your data set may not be robust enough to answer the question at hand. Otherwise, I agree with the general sentiment that running all models may not be the preferred approach, but is suitable when apriori knowledge is insufficient for justifying the inclusion of some models while precluding others. Michael Cooperman
Re: [ECOLOG-L] AIC, data-dredging, and inappropriate stats - correction
Hello fellow Ecologers- Yesterday I offered a response to the original posting on issues surrounding use of AIC. Sadly, I failed to proof what I wrote and thereby submitted some wrong stuff -- I wrote, "if 2 different measures of fit (i.e., delta AIC value and r^2) support different conclusions" -- Of course, delta AIC is not a measure of goodness of fit, it is a measure of the "quality" (i.e., information loss) of a given model in comparison to other tested models. Hence, in my response to point 3 of the original post, which read: 3. Use of other 'fit' statistics along with the model-selection approach. I often see people reporting other statistics (e.g. p-vals, r-squared) in combination with the AIC scores. My statistician friend says that this is totally inappropriate, and uninformative. My response should have beensince delta AIC and r2 measure different things, I think it can be appropriate to report them together; not as equal measures for model selection but as r2 informing on the relative value of the AIC solution (i.e., if AIC indicates model X is the best, but it has an exceptionally low r2 (assuming r2 is suitable to use as the relationship is linear) then even the best model identified by AIC is still pretty weak. Sorry for any confusion. Michael
Re: [ECOLOG-L] Rhetorical question on trees
Hi - I suggest you look into the work of Ray Calloway, prof. at U Montana. He's done some fascinating work along these lines. Cheers, Michael Cooperman -Original Message- From: Ecological Society of America: grants, jobs, news [mailto:ECOLOG-L@LISTSERV.UMD.EDU] On Behalf Of Martin Meiss Sent: Wednesday, April 13, 2011 9:19 AM To: ECOLOG-L@LISTSERV.UMD.EDU Subject: Re: [ECOLOG-L] Rhetorical question on trees It's probably more reasonable to think of the soil-building properties of leaves (and other things that fall out of trees, like twigs, fruit, bird poop, etc.) at the level of the forest rather than at the level of the individual tree. After all, leaves don't fall straight down, and after they hit the ground, they don't necessarily stay where they fall (wind, you know). Even if they did, there is no guarantee that each branch of a tree has a root waiting under it. Additionally, understory plants growing beneath the tree compete with the tree for water and nutrients, since their roots occupy the same soil. Thus, in a situation where water limits growth, a tree, by enriching the soil below its crown, could hurt itself by favoring the growth of small plants that compete with it for water. If a tree is to benefit nutritionally from loss of leaves, etc., probably the best thing is to minimize the lose by pulling as much nutrient as possible from the parts to be shed. This is what's going on when leaves turn color before falling off in autumn of the temperate zone. However, plants have never evolved a way (to the best of my knowledge) of remobilizing cellulose, hemicellulose, or lignin, so these materials can't by scavenged metabolically. However, they are also materials not containing much of nutritional value; their loss is primarily an energy loss. The benefit of withdrawing nutrients from leaves leads to selective pressure for proper timing of the withdrawal. If trees do it too early, they loose part of the growing season, and if they do it to late, frost can kill the leaves before the nutrient is withdrawn (and dead leaves no longer have the metabolic machinery needed to support withdrawal of nutrients). In my yard I have an introduced species of mulberry, far from the climate where its ancestors evolved, and in the fall it seldom reads the climatic cues (day length and temperature) correctly. Its leaves stay bright green till a hard frost kills them, then they fall to the ground, sometimes in a single night, still bright green. Surprisingly, the tree still grows like hell, and every few years I have to trim a lot of wood out of it. Martin M. Meiss 2011/4/13 Martin Koechy > Hi Geoff, > > You are right, that's what trees tend to do, but the intensity is variable. > The keyword is "island of fertility" if you look for more information and a > classical paper on this subject is Zinke PJ (1962) The pattern of influence > of individual forest trees on soil properties. Ecology 43: 130-133. > > Cheers, > > Martin > > Am 2011-04-13 um 04:59 schrieb Geoffrey Patton: > > > ? To what degree do trees self-fertilize by dropping leaves and building > their own humus ? They capture energy from the sun and nutrients from the > air (and soil) and some of that production feeds the soil upon which the > following year's growth depends. The soil biota processes the wastes, > further captures atmospherically-deposited nutrients, and makes it all newly > available for further growth, I would imagine. Apologies for being a marine > biologist but this seems like something that might have been researched > already. Yes or no? > > > > > > > > Cordially yours, > > > > Geoff Patton, Ph.D. > > 2208 Parker Ave., Wheaton, MD 20902 301.221.9536 > > --| http://sci.martinkoechy.de | > Dr. Martin Köchy (Koechy) > > Johann Heinrich von Thünen-Institut > -Bundesforschungsinstitut für Ländliche Räume, Wald und Fischerei- > Institut für Agrarrelevante Klimaforschung > > Johann Heinrich von Thuenen Institute > -Federal Research Institute for Rural Areas, Forestry and Fisheries- > Institute of Agricultural Climate Research > > vTI-AK * Bundesallee 50 * 38116 Braunschweig * GERMANY > Telefon: +49-531-596-2640 * Telefax: +49-531-596-2699 > http://www.vti.bund.de/de/startseite/institute/ak.html > skype: martinkoechy > --- & --- > AG Vegetationsökologie & Naturschutz|RG Veg. Ecology & Nature Conserv. > Universität Potsdam| University of Potsdam > Am Neuen Palais 10 * 14469 Potsdam * GERMANY > > www.bio.uni-potsdam.de/professuren/vegetationsoekologie-naturschutz >
Re: [ECOLOG-L] food selectivity index of non-countable items
Hello Gianluca,
There are a couple of ways to answer your question. First, of course it is
"feasible" to use a volumetric approach, as the ratio of relative volume
present in gut to relative volume present in environment is a measure of
"selectivity."
However, there's a reason why you don't see this often done. Foods such as
detritous, CPOM, FPOM etc are rarely "rare" in the environment, so if that is
what a consumer specializes in, that is what it will get as barriers to
detritous typically don't exist. Hence, its electivity index will be 100%
detritous. It is a very rare case when a "carnivour" switches to feeding lower
on the food chain (from hetertrophs to autotrophs) as they simply lack the
physiology to do so. For an omnivour, the typical question is where does the
energy come from - i.e, the caloric content of the items in the gut. A single
small fish in the gut will likely contribute much more energy to the total diet
that a large volume of detritous or plant matter or comprarable food. For this
reason, if a consumer has access to multiple types of accpetable foods at a
variety of trophic levels, it will always choose the high energy food (if a
barrier to access exists then it is not a potential food source!
and it is not a matter of selectivity).
These 2 points demonstrate why electivity indicies are typically only
used on high trophic level consumers selecting from a variety of similar prey
types.
You do not provide details of your project so perhaps there are special
circumstances, but based on what you wrote, I don't see why you are doing
electivity analysis.
Sent from (and mis-spelled on) my iPhone.
On Aug 11, 2011, at 2:10 PM, "Gianluca Polgar"
wrote:
> Dear all,
>
> thank you to all of you who replied on food selectivity index of
> non-countable items.
> Unfortunately, my methodological problems are still largely unsolved.
>
> If anyone is interested in this topic and would like to contribute, please
> continue to send suggestions, comments etc.!
>
> Thank you!
>
> Gianluca
>
>
> -Original Message-
> From: Gianluca Polgar
> To: ECOLOG-L
> Sent: Tue, Aug 2, 2011 11:40 pm
> Subject: [ECOLOG-L] food selectivity index
>
> Dear all,
>
> I'm going to estimate the food selectivity of some fishes and I'd like
> to adopt the food selectivity index of Berg (1979).
>
> This index utilises the numerical abundance of food items, measured both
> in the gut and in the habitat.
> Nonetheless, a considerable percentage of food items is NOT countable
> (e.g. detritus, plant material)...
>
> My question is: would it be a feasible option to utilise a measure of
> bulk of food items (e.g. volume) instead of amounts?
> Is anyone aware of any other indexes of food selectivity that could be
> adopted with non-countable items?
>
> Any suggestion will be more than welcome!
>
> All the best,
>
>
> Gianluca
>
>
> --
> Gianluca Polgar Ph.D.
> Senior lecturer
> Institute of Biological Sciences
> Institute of Ocean and Earth Sciences
> Faculty of Science, University of Malaya
> 50603 Kuala Lumpur, Malaysia
> Tel.: 017-6223549
> Fax (ISB): 03-79674178
> e-mail: gianluca.pol...@gmail.com
> www.themudskipper.org
>
> O___!__/__
> {__)_\
Re: [ECOLOG-L] climate change and ecological traps
Hello Bruce, Have a look at the literature on the early river entry phenomenon of Late Run Sockeye of the Fraser River. See web page of Dr. Scott Hinch at UBC, Vancouver Canada, for a slew of papers. Michael - Michael Cooperman, PhD National Research Council - Research Fellow in residence at NOAA-Fisheries, NE Fisheries Science Center - Maine Field Station Atlantic Salmon Research and Conservation Task 17 Godfrey DR., Suite 1 Orono, ME 04473 (work) 207-866-4166 (cell) 207-974-9846 (fax) 207-866-7342 (pls call before faxing) email: michael.cooper...@noaa.gov - Bruce Robertson wrote: I'm curious to know if anyone is aware of any potential ecological or other evolutionary traps caused directly (e.g. climatic cues related to migratory ecology, emergence, flowering time asychrony with pollinators, etc) or indirectly (e.g. resultant species interactions) by climate change. Climate change is predicted to alter the temporal and spatial relationships between organisms (and organisms and their abiotic environment) and should be predicted, then, to alter the reliability of cues used by organisms to guide various behaviors. I should say that something like earlier departure/arrival by migratory birds may result in reduced fitness outcomes, but may not be a trap unless there are other 'available' behavioral choices for the organism to make. In this way, migratory departure may be a rather hardwired behavior with little variability. It could be possible in this example that regional variation in the degree of climate change could trigger some local populations to migrate, while not othersthis might constitute a trap. Instead, such a case my simply represent organisms experiencing evolutionary lag and 'making the best of bad situation'. ...aside from this rather hypothetical example, traps due to climate change seem particularly likely and I'm surprised that I have not yet read a paper on this topicI'd love to hear from anybody with either theoretical ideas, anecdotal evidence or research in progress as I'm putting together a manuscript that would benefit from such ideas. Best,
Re: [ECOLOG-L] evolution for non-scientists textbook
Hello - Although not a text book per se, Richard Dawkins' book The Selfish Gene would provide an excellent description of evolution and ample discussion material. Its been several years since I read it, but I think it was written to be easily accessible to a lay audience. Alongthe same lines, E.O. Wilson's Diversity of Life would also merit consideration. Michael Cooperman jbowen wrote: Hi All: In the fall I am going to be teaching an Evolutionary Biology course for students in the social sciences and humanities. No prior coursework in the natural sciences is required. I am curious if the list might have recommendations for a textbook that is appropriate for this audience. Thanks in advance for your input.
[ECOLOG-L] Predator swamping, prey buffering, etc.
Hi Folks- In the course of some recent work, I've come across several apparently inter-related terms. I'm curious to know if people with experience with these issues agree with the following definitions or if you'd care to offer alternatives. My main interest is in learning of how others address the differences between swamping and buffering. Also, if anyone is familiar with a published source that brings these concepts and terms under a single cover, I'd love to hear about it. Cheers. Michael Cooperman Synchronized (prey) behaviors -- when the individuals of 1 or several populations all execute a key event at the same time (i.e., synchronisity of hatching dates, timing of juvenile dispersal migrations, etc.). "Predator swamping" is often invoked as the selective force for this synchronous behavior, although empirical evidence for this mechanism is lacking. Predator swamping -- when a population of a prey species increases its overall survival via overwhelming the predator field (either via satiation or reduced encounter rates). This is a 2 species system (predator and prey). Prey Buffering -- when 1 prey species gains an advantage via the actions of a 2nd prey species upon a common predator (i.e., loses of a rare prey species decreases as the abundance of a more common prey species increases because the common predator keys on the more common prey). (This is a 3 species system; 2 prey, 1 predator). Prey switching -- a concept related to the foraging selectivity of predators, consistent with optimal foraging theory. In this case, an individual of a prey species may gain an advantage by being "early" as the predators have not yet keyed on that species as prey.
Re: [ECOLOG-L] effects of early spring on fish spawning?
In my experience the question of whether or not fish populations are impacted by "earlier spring" depends, in part, on their behavior ie., migratory or sedentary. In general, sedentary species should experience less impacts because their entire ecosystem (i.e., a pond or a lake) is changing as a unit - ie., earlier spawn and early hatch date of fish eggs is matched by earlier timing of the spring plankton bloom so events are not desynchronized. For migratory species you encounter greater potential negative consequences. For example, Fraser River sockeye salmon are entering freshwater and reaching spawning grounds at earlier dates but spawning still occurs at the same time in the fall. Hence, adult sockeye are spending more time in freshwater, and this leads to "premature" exhaustion of energy reserves, longer times for disease to incubate, etc. Net result is greater pre-spawn mortality. A similar disconnect occurs during the downstream migration of young anadromous fishes -- their freshwater habitats are changing at a differnet rate than their marine environment, so young may arrive to the ocean before the ocean has reached sufficient productivity. Although not a precise example, the work of Holtby et al from Carnation Creek BC Canada serves as a good empirical example of how disruption of the timing between life history events has non-linear long term population consequences. Cheers, Michael Cooperman, PhD. -Original Message- From: Ecological Society of America: grants, jobs, news [mailto:ECOLOG-L@LISTSERV.UMD.EDU] On Behalf Of Scott Ruhren Sent: Friday, March 23, 2012 9:28 AM To: ECOLOG-L@LISTSERV.UMD.EDU Subject: Re: [ECOLOG-L] effects of early spring on fish spawning? Hi David, River herring (common name blue-back herring and alewife, anadromous Alosa species) have been spotted already far upstream and that is early for RI. Scott Ruhren, Ph.D Senior Director of Conservation Audubon Society of Rhode Island 12 Sanderson Road, Smithfield, RI 02917 Tel: 401-949-5454 ext. 3004 Fax: 401-949-5788 sruh...@asri.org Connecting People With Nature Stay informed all month long with eWing, Audubon's monthly e-newsletter. Follow us online: www.asri.org ~ Twitter ~ Facebook Consider supporting Audubon by making a donation today! -Original Message- From: Ecological Society of America: grants, jobs, news [mailto:ECOLOG-L@LISTSERV.UMD.EDU] On Behalf Of David Inouye Sent: Thursday, March 22, 2012 2:42 PM To: ECOLOG-L@LISTSERV.UMD.EDU Subject: [ECOLOG-L] effects of early spring on fish spawning? The Diane Rehm show on WAMU this morning featured an hour about the effects of the mild winter and early spring: http://thedianerehmshow.org/shows/2012-03-22/effects-mild-winter Audio recorded at: http://thedianerehmshow.org/audio-player?nid=15792 One question that came up was about the potential consequences of early spawning by largemouth bass and other fish. My guess was that there weren't likely to be potential consequences such as were experienced by plants, insects, and other animals in 2007, when an early warm spell in March like this year's was followed by a hard freeze in April. But I'd be interested to hear from aquatic/fish biologists who are more knowledgeable. David Inouye Dr. David W. Inouye, Professor Associate Chair, Director of Graduate Studies Dept. of Biology University of Maryland College Park, MD 20742-4415 Rocky Mtn. Biological Laboratory PO Box 519 Crested Butte, CO 81224 ino...@umd.edu 301-405-6946
Re: [ECOLOG-L] designing for migration routes
There is much excellent literature on corridor design for various taxa. Good places to start might be Machtans, C.S., M. Villard and S.J. Hannon. 1996. Use of riparian buffer strips as movement corridors by forest birds. Conservation Biology 10: 1366-1379. Naiman, R.J. and K.H. Rogers. 1997. Large animals and system-level characteristics in river corridors: Implications for river management. Bioscience 47: 521-529. Taylor, P.D., L. Fahrig, K. Henein and G. Merriam. 1993. Connectivity is a vital element of landscape structure. Oikos 68: 571-573. Good luck, Michael Cooperman -Original Message- From: Ecological Society of America: grants, jobs, news [mailto:ECOLOG-L@LISTSERV.UMD.EDU] On Behalf Of Charles Andrew Cole Sent: Monday, March 26, 2012 2:33 PM To: ECOLOG-L@LISTSERV.UMD.EDU Subject: [ECOLOG-L] designing for migration routes Hi, I have a grad student in China at the moment looking at ways of designing wildlife corridors through a national park. She has now realized she needs to find some way of designing migration corridors based upon the steep topography in the park. Does anyone have some good sources of information that relate migration corridors with topography? Many thanks. Andy Cole -- Charles Andrew Cole, Ph.D. Associate Professor of Landscape Architecture and Ecology and Graduate Program Coordinator Department of Landscape Architecture 329 Stuckeman Family Building Penn State University University Park, PA 16802 ca...@psu.edu 814.865.5735
