tag:blogger.com,1999:blog-6890587739757813022.post7671649874813278175..comments2023-10-25T06:08:57.382-07:00Comments on Perspectives in (human) ecology: Week 8 Background: how humans alter biogeographic patternsHuman macroecology adminhttp://www.blogger.com/profile/13967591733070493102noreply@blogger.comBlogger17125tag:blogger.com,1999:blog-6890587739757813022.post-55730148447233828852007-10-09T09:39:00.000-07:002007-10-09T09:39:00.000-07:00Wouldn't the question of whether weather or humans...Wouldn't the question of whether weather or humans caused patterns of megafaunal collapses be answered by looking at other factors as well? Lyons et al suggests that a variety of human behaviors contributed and that the overkill hypothesis is a subset of those behaviors. How difficult would it be to create a comprehensive data set that included overharvesting when a popualtion moved to a new region, changes in habitat and introduction of new diseases and hunting?helen elizabethhttps://www.blogger.com/profile/14857441446149468625noreply@blogger.comtag:blogger.com,1999:blog-6890587739757813022.post-83943934488514341732007-10-09T09:26:00.000-07:002007-10-09T09:26:00.000-07:00Humans have decimated almost every environment we ...Humans have decimated almost every environment we have every inhabited. We completely wiped out all protohumans and still today quickly encroach on every environment we enter to extract resources. It seems difficult to ever doubt the role of humans in mammal extinctions, especially when the fossil records clearly indicate that we coexisted in many areas at the same time...but, then as surovell states, these timing events only occurred on the large landmasses....helen elizabethhttps://www.blogger.com/profile/14857441446149468625noreply@blogger.comtag:blogger.com,1999:blog-6890587739757813022.post-58329635664218700532007-10-09T09:13:00.000-07:002007-10-09T09:13:00.000-07:00This comment has been removed by the author.helen elizabethhttps://www.blogger.com/profile/14857441446149468625noreply@blogger.comtag:blogger.com,1999:blog-6890587739757813022.post-21605200855650631352007-10-08T23:00:00.000-07:002007-10-08T23:00:00.000-07:00Surovell provides a nice overview of hypotheses fo...Surovell provides a nice overview of hypotheses for Pleistocene megafaunal extinctions. One thing that struck me about Diamond's "sitzkrieg hypothesis" is that such anthropogenic impacts as forest clearing and secondary burning would probably expand grasslands, and many megafauna, esp in the Americas, were grassland species. <BR/> -- BillHuman macroecology adminhttps://www.blogger.com/profile/13967591733070493102noreply@blogger.comtag:blogger.com,1999:blog-6890587739757813022.post-63533048003745239672007-10-08T20:43:00.000-07:002007-10-08T20:43:00.000-07:00Why wasn’t Africa as affected? They suggest that s...Why wasn’t Africa as affected? They suggest that since human hunting capacity grew gradually in Africa, whereas it exploded onto the other continents, African mammals had time to adapt to human predation before being totally wiped out. Is there something else that makes Africa different? The megafauna of Africa might have a latitudinal advantage over North America, being able to maintain larger, denser populations? And Africa might have had an area advantage over South America, which is at a similar latitude?pablohttps://www.blogger.com/profile/10776192960838440402noreply@blogger.comtag:blogger.com,1999:blog-6890587739757813022.post-2540952616137333452007-10-08T20:41:00.000-07:002007-10-08T20:41:00.000-07:00Lyons shows that the species distributions were bi...Lyons shows that the species distributions were bimodal before the extinctions. That’s interesting, eh? I don’t think they suggest an explanation, do they? The second mode gets eliminated in North and South America, making their current distributions significantly different from Africa, where it persisted.pablohttps://www.blogger.com/profile/10776192960838440402noreply@blogger.comtag:blogger.com,1999:blog-6890587739757813022.post-58355233544818809692007-10-08T20:34:00.000-07:002007-10-08T20:34:00.000-07:00With regards to the Sutherland paper, it seems rat...With regards to the Sutherland paper, it seems rather counterintuitive that the number of televisions per 1000 people didn’t correlate with the number of languages in that country. Perhaps were area and population density controlled for, a pattern may appear. Although some larger cities (e.g. London) may still remain linguistically rich, more remote and less wealthy cities may show less diversity despite similar population size (e.g. Tehran). Either way, this is nowhere near the richness linguistic of New Guinea and the surrounding area. A greater concentration of wealth (i.e. televisions) in the cities would also be expected compared with more rural populations where a greater linguistic richness would tend to exist.Michaelhttps://www.blogger.com/profile/14951941963167223313noreply@blogger.comtag:blogger.com,1999:blog-6890587739757813022.post-68988679827425579292007-10-08T20:07:00.000-07:002007-10-08T20:07:00.000-07:00Why did some fauna go extinct on some continents b...Why did some fauna go extinct on some continents but not others? The horse and camel were domesticated in the East but apparently wiped out in the West.Justin Smithhttps://www.blogger.com/profile/14545908996745567861noreply@blogger.comtag:blogger.com,1999:blog-6890587739757813022.post-2875918387557811212007-10-08T18:56:00.000-07:002007-10-08T18:56:00.000-07:00Sutherland mentions that as languages become rarer...Sutherland mentions that as languages become rarer, they may be less appealing to learn. How much of this is an effect of globalization, and the simple fact that more and more schools are teaching certain languages to increase the students' opportunities?Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-6890587739757813022.post-19607591854913515032007-10-08T18:53:00.000-07:002007-10-08T18:53:00.000-07:00The Lyons paper categorizes redlisted mammals into...The Lyons paper categorizes redlisted mammals into groups based on their risks of extinction, whether due to intrinsic factors, loss of habitat, or hunting. Isn't there the possibility that there were interactions between these risks, that animals may have already been dying off due to loss of habitat, and this made them easier to hunt? <BR/><BR/>The authors also refer to a higher return for hunting larger animals, which is why these are the targets. However, there is also significantly more risk inherent in taking out a large animal as opposed to something small, which would have a significant effect on the return.Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-6890587739757813022.post-16025750136731205002007-10-08T18:43:00.000-07:002007-10-08T18:43:00.000-07:00Lyons et al. are quick to dismiss life history the...Lyons et al. are quick to dismiss life history theory on page 348 because smaller fauna with the same life history traits as large fauna who died off, survive. Wouldn't there be a difference in LH traits because of the size difference?David Odegardhttps://www.blogger.com/profile/02458221075316581740noreply@blogger.comtag:blogger.com,1999:blog-6890587739757813022.post-5913653412653778212007-10-08T18:40:00.000-07:002007-10-08T18:40:00.000-07:00In the Lyons et al. paper, they discuss how patter...In the Lyons et al. paper, they discuss how patterns in modern hunting have been the main reason large mammals are either endangered or extinct and use this to support their argument that earlt human hunters would have also targeted large mammals. While this may be true, did the authors consider that modern hunting is done mainly for sport and not subsistence? Wouldn't you expect different patterns with this non-subsistence based goal in hunting? Did the authors restrict the hunters to those groups with hunting practices similar to those used by early human hunters?tlvandeesthttps://www.blogger.com/profile/05345600600350316006noreply@blogger.comtag:blogger.com,1999:blog-6890587739757813022.post-41758219153833884122007-10-08T18:34:00.000-07:002007-10-08T18:34:00.000-07:00In Surovell's paper, if we have the data of Africa...In Surovell's paper, if we have the data of Africa and Asia for figure 2, what should we expect?Unknownhttps://www.blogger.com/profile/12334058277940978026noreply@blogger.comtag:blogger.com,1999:blog-6890587739757813022.post-66096189561755085472007-10-08T18:04:00.000-07:002007-10-08T18:04:00.000-07:00REPOSTED:Given that the graphs on 347 plot log(mas...REPOSTED:<BR/><BR/>Given that the graphs on 347 plot log(mass) on the x axis, there appears to be a lower threshold for carnivores that went extinct. Observe that in both N. and S. the carnivore extinctions seem to be shifted to the right. This could be just coincidence, but if it isn't then it would indicate that larger carnivores went extinct than other orders. Is this due to the fact that the large carnivores were also eating the large game that went extinct because of the humans? <BR/><BR/><I><BR/>PS<BR/>Posting here as I thought the first one was the one to put comments on, but this one is where the comments appear to be. <BR/></I>Steven M.https://www.blogger.com/profile/00306296902750814674noreply@blogger.comtag:blogger.com,1999:blog-6890587739757813022.post-11032993294981524222007-10-08T16:20:00.000-07:002007-10-08T16:20:00.000-07:00Taking predator-prey foraging models may help to e...Taking predator-prey foraging models may help to examine megafauna extinctions during the late Pleistocene. Given that the handling time for megafauna is relatively high, at what encounter rate would it make sense to let the mammoth graze? Would the encounter rate eventually be so low that it would be better to go after a conejo? I guess this is not inconsistent with the Lyons et al paper, since they cover their butts by allowing for other secondary (climate) causes of extinction.Danhttps://www.blogger.com/profile/15532035790906598732noreply@blogger.comtag:blogger.com,1999:blog-6890587739757813022.post-87844859996548106552007-10-08T13:41:00.000-07:002007-10-08T13:41:00.000-07:00I noticed that in the Lyons paper, megafaunal exti...I noticed that in the Lyons paper, megafaunal extinctions in Eurasia aren't discussed, although they are in the Surovell paper. Could the gradual megafaunal extinction in Eurasia and the smaller, gradual extinction in Africa be the exceptions that prove the rule?<BR/><BR/>Also, to what extent could the extinctions be the result of a combination of several factors? For example, could hunting AND land use by humans AND climate change AND reduction in numbers of keystone herbivores have all acted together to lead to the extinctions in the Americas? Would this account for the size bias in extinction?Shawn "Fred" Whitemanhttps://www.blogger.com/profile/08607489891707432348noreply@blogger.comtag:blogger.com,1999:blog-6890587739757813022.post-69598017924475196592007-10-07T19:56:00.000-07:002007-10-07T19:56:00.000-07:00How different are these glacial- interglacial peri...How different are these glacial- interglacial periods that Lyons mentions? What if the last one is significantly different than the previous 20? Even though knowing these variations may not explain the mammalian extinction, it should be more thoroughly explained if it is going to be a foundation to their argument.Myra Villaloboshttps://www.blogger.com/profile/12080437276571428355noreply@blogger.com