More people and more land development means fewer birds.
From the heartland's whippoorwills and meadowlarks to the Northern bobwhite and common terns of the nation's coasts, 20 common bird species tracked by the National Audubon Society have seen their numbers fall 54 percent overall since 1967, with some down about 80 percent, the group reported Thursday.
Most of the trouble lies with loss of bird habitat, and has for decades, due to expanding agriculture and suburban development. The Rufous hummingbird's population has fallen 58 percent due to logging and development in its Pacific Northwest breeding range – and in its winter range in Mexico. The same thing has happened to whipporwills, whose numbers are down 57 percent due to loss of their forest habitat. At the same time, scientists say changes in migration patterns due to global warming are emerging, too.
"Habitat loss is still the major concern," says Greg Butcher, Audubon's bird conservation director in an interview. "But we're also seeing increasing impact from large-scale problems like global warming."
Losses due to global warming are speculative at this point. But loss of land to human use is not speculative. Destruction of rain forests in the tropics will drive many species to extinction. Both industrialization and population growth are driving the loss of land.
This trend could get much worse. My fear with biotechnology for biomass energy is that biotechnology will make more land useful for human purposes. If genetic engineers create plants that make land more usable for energy production then use of land for energy production will cause orders of magnitude greater loss of habitats than is caused by drilling for oil and construction of oil pipelines. Shifting of land into production for biomass energy will get added to expansion of land use for food crops, logging, and human settlements.
The habitat loss problem is going to get much worse even without a massive shift to biomass energy. The population of the United States will hit about 400 million by 2050. Most of that population growth will come from immigrants and from children of immigrants.
That population growth rate is probably going to go up if the S.1348 immigration amnesty bill passes Congress. Why? Immigration amnesties cause fertility spikes.
According to a 2002 study by demographers Laura E. Hill and Hans P. Johnson of the Public Policy Institute of California, due to the 1986 amnesty (another "comprehensive" compromise, combining legalization with enforcement provisions that were never enforced), "Between 1987 and 1991, total fertility rates for foreign-born Hispanics [in California] increased from 3.2 to 4.4" expected babies per woman over her lifetime.
I believe we already have too many people on planet Earth and that we are going to lose a large number of species due to population growth and industrialization. Eventually we are going to develop rejuvenation therapies and current projections of future population growth will turn out to be very low. Seems to me we have about 4 choices with population growth:
My guess is that the fourth option is the most likely. The instinct to reproduce is incredibly strong (even as many intellectuals erroneously claim we've somehow escaped our instincts). Also, the development of rejuvenation therapies seems inevitable barring a catastrophe that wipes out the human race.How can the fourth option be prevented? Maybe people will migrate to online virtual reality living and raise AI children. I doubt it. Maybe a Borg consciousness AI will take over a world government and control human behavior. For example, a massive AI (or a secret cabal of scientists and industrialists) could design viruses that infect the entire human race and reprogram their brains to dampen down desires to reproduce.
By Randall Parker at 2007 June 17 08:56 AM Trends Habitat Loss | TrackBackI don't think we've escaped our instincts, but neither do I think we have an instinct to "reproduce"; That's a fairly sophisicated concept for an instinct to cope with, don't you think?
Rather, I think we've got an instinct to have sex, and an instinct to raise the resulting kids. Absent birth control, it amounts to the same thing as an instinct to reproduce, but we're not absent birth control. It's pretty hard to explain the demographic transition if we actually had a reproductive instinct.
BTW, you seem to have overlooked an option: There's a whole universe out there people who want to have children could expand into, with technology not a lot more advanced that what we have now.
Brett,
First off, yes of course we have an instinct to have sex. I suspect that most births are still the result of unplanned pregnancy. So that's an important instinct even today.
Second, I'm thinking of the strong desire to have kids. That's not just a desire to raise them once you have them. The desire to have kids in the first place is so very strong in so many people that it looks like an instinct to me.
Reproduction is certainly instinctive (and conditioned). That doesn't mean that women at the age of 100 want to dedicate another 20 years to the task. Fertility rates are a function of women's rights and wealth. The more of either, the lower the fertility. This is a global phenomenon.
The more likely long term future (there I go again working above my pay grade) is that our ability to handle increasing population with reduced environmental impact will continue to grow (that's how the environment in the US continues to improve despite steadily increasing population.) Once we crack the energy problem (in the next couple of decades) we'll be good to go for a lot more folks. The world is still quite unevenly populated. We will likely be able to "terra-form" many of today's not very habitable places and still have as much elbow room as the US has today. Another reasonable future takes us into a "matrix"-like future where satisfying our reproductive and other instincts happens virtually with essentially no environmental impact.
Larry, I think you ignore a point Randall has made on his blog numerous times:
Until recently, the desire to have sex was strongly selected for. Effective birth control reduced the reproductive fitness of women who desire to have sex more than they desire to have children. This increases the relative reproductive fitness of women who desire to have children as much as (or even more than) they desire to have sex. Natural selection will now make the latter cohort an ever growing proportion of the population, and they will reverse the trends to lower fertility.
Your "global phenomenon" is based on the short-term effect of birth control while ignoring the long term effect of natural selection.
Maybe people will migrate to online virtual reality living and raise AI children. I doubt it.
I don't do Second Life or those kinds of virtual reality games, but I don't get the impression that many people who do are raising virtual kids. Reproduction may be an instinct, but childrearing seems more like something to escape from than to.
Major bird species are being hit even harder by communicable viruses:
Several common species of North American birds have suffered drastic population declines since the arrival of the West Nile virus eight years ago, a new study has found. Of the 20 species included in the study, American crows were the hardest hit, declining about 45 percent overall from 1998 to 2005. Populations of American robins, chickadees, eastern bluebirds, blue jays, tufted titmice and house wrens also dropped.Crows are amazing birds, with complex social interactions and a keen intelligence that tops the avian world. Robins live almost exclusively on the insects that make going outdoors on a muggy summer evening a little less heavenly. Blue jays are mean pursuers of formidable bugs like wasps and bees. Wrens fly with an awing dexterity. The hit taken by the other songbirds listed means the sounds flowing in through the open window on a crisp spring morning are becoming a little less sweet.
The culprits are mosquitoes carrying West Nile virus, one of several diseases that has recently begun calling the US "home" (it was introduced domestically in the late nineties after hitching a ride on a travelling creature from Uganda) thanks to the free-flow of people and stuff into the country that our elites love so much.
Bob
Natural selection? Long before natural selection has a material affect, we'll be so technologically advanced that all these problems will seem like bubonic plague does to us 3rd millienium types today - a distant memory.
It's also true that around 100 years ago, eugenicists and others decided that since the poor had more children than the rich, society was doomed to perpetual misery. Not quite.
Momochan
In the matrix, you'll get to choose everything you want about everything. Don't want labor? No problem. Baby sleeps through the night from day 1? OK. Kids that are smart but not smart-alec? Done. You get the idea.
Seems to me we have about 4 choices with population growth....Another broad class of choices are available. It seems natural selection must tend to work in favor of peoples with the means and willingness to choose intelligently among the full panoply of possible actions, and also in favor of peoples with the means and foresight to protect themselves. I've never experienced anything other than relative peace, and I prefer it. However, there's no use in our ignoring the advantage one people often has at the expense of another, through such simple expedients as extinguishing them, pushing them out, or enslaving them. My ancestors, I'm told, were part of a centuries-long migration that largely exchanged one populace for another throughout the Western Hemisphere. As a result of their efforts, I'm here today, reading hearsay on Israel, the Balkans, the American Southwest (or, if you prefer, the Mexican North), Europe, England, Kashmir, Tibet, Thailand, Darfur, and other places, no doubt, that haven't sprung to mind. If we resist being reminded of the usefulness of murder and oppression because we don't want to be murderers or oppressors, we should nevertheless accept being reminded, so we can aim not to be murdered or oppressed.
Larry,
Technology can change the evolutionary landscape, but it cannot alter the inexorable nature of reproductive fitness and natural selection.