|
Edited on Sun Aug-27-06 08:11 PM by Gato Moteado
now, i'm no scientist but i also live here in costa rica and while i, like every scientist in the world, believe global warming is a threat i do think that the author of that letter is ignoring other factors responsible for the changes he sees.
also, he contradicts himself by stating in paragraph three that there's a water shortage in the lake arenal area due to lack of rain but in the next paragraph he claims the thuderstorms are stronger and they are setting records for rainfall rates. which one is it?
ok, he's living in the lake arenal area. i'm not an expert in this area but i'll tell you what i do know. lake arenal is overrun with gringo realtors buying up land and developing houses with a lake view and selling them to more gringos who are flocking to the area. and, long before that started i suspect the heavy deforestation there had taken place in order to make room for cattle. i had a friend that lived in the lake arenal area for about a year. she is a photographer and she sent me countless photos taken in every direction possible and the thing that stuck out in these photos was the lack of forest in the area. the mountainsides were wide green pastures. and as for the water shortages in the reserves, well it only makes sense that as the population grows in an area, water usage will spiral out of control. especially with gringos that really aren't all that hip on water conservation.
i would be willing to bet that the deforestation, habitat destruction and intrusion by wealthy and semi-wealthy ex-pats and euros have more to do with every problem he is experiencing than global warming. does that mean i don't think global warming is a threat? no. i just doubt that the dramatic changes he's seeing that are happening so quickly here in the tropics are attributed to global warming.
so, let's look at some of his comments and see if we can find some more rational reasons for the problems he's facing:
"Terrific winds, too -- in my two years living on this property, I have never seen the wind take down a tree until last week, when a storm in the middle of the night brought down three on my property alone, and a huge one not far from me."
ok, tropical hardwoods and other native trees in the tropics are resilient enough to withstand hurricanes. in normal conditions they wouldn't even be fazed by the winds from a T-storm. but these are not normal conditions. like i said, the arenal area has been heavily deforested. when deforestation takes place, especially in a rainforest, the earth erodes quickly from the intense rainfall. so these old, large, heavy trees don't have enough earth to hold them in place. thus, high winds will knock them down. i see it all the time in and around the edges of pastures and other deforested areas. in a forested area, this doesn't happen, unless the trees are very old and rotted and this is a good thing since fallen dead trees provide habitat for certain types of wildlife.
Extremes of temperature are becoming more common, both hot and cold. The highest temperature ever recorded in this town, 95 degrees, was recorded last year, and temperatures in the upper 80's, which old timers tell me were unheard of until recently, are almost the norm now, whenever there is a day that remains sunny well into the afternoon.
as more and more forest disappears and is replaced with more and more concrete infrastructure, this is what happens. i lived in miami during hurricane andrew. after the hurricane knocked down all the old urban trees, the daytime temperatures increased significantly there. so, this is no surprise. and it also makes sense that the wind at night will cool things down a bit more since there is no canopy and forest to hold the warmth of the sun into the evening. again, it's what i would expect.
The difference between the rainy season and the dry season is being blurred. We get lengthy rainy periods during the dry season now, and stretches of several days without rain during the rainy season. That never used to happen here in this town.
as areas are deforested they become more arid and i would think it would be totally normal for rainfall patterns to change. i don't see these types of changes occurring in the zones that have less population and little deforestation.
Now I rarely hear it any more, and the once-constant chatter and chirp of birds is much less evident -- there are times when it is ominously quiet in the rainforest across the street from where I live.
well, duh. songbirds are moving on to forested areas where they don't have gringos across the street with their cars, lawnmowers, powerboats, and other polluting, noise making machinery.
Winters once brought large numbers of Baltimore orioles, scarlet-rumped tanagers, blue tanagers and western tanagers to my garden, but I rarely see any of those any more, especially not in flocks.
these are migratory birds. with global warming and warmer winter temperatures in the northern zones it's certainly possible that they are expanding their wintering ranges farther north into these temperate zones and not flying as far south. but, i would contend that habitat destruction, pesticide use and pollution in their summertime habitats are having a much greater impact on their numbers. less are making it down to costa rica each year because their populations are shrinking. and the ones that do come head to areas with less concentrated human populations.
Instead of those birds, I see a lot more Nicaraguan grackles (which only recently appeared in Costa Rica), big-tail grackles, blue magpies, red-lored parrots, flycatchers and other non-migratory species that were once uncommon, at least seasonally.
yes, these are all birds that tend to find a niche in urban areas. anyone who has lived in the temperate and subtropical areas of the US can attest to this because they've seen the population explosion of grackles in the cities and suburban areas. they do well around human populations because they've learned to scavenge for food in trash and litter provided by people. parrots are cavity nesters, and there are no lack of cavities in the sides of buildings and bridges and other infrastructure so parrots will happily colonize in urban areas.
furthermore, with the rise of grackle populations, the songbirds will definitely leave the area because grackles are also nest raiders. so this could be another contributing factor to the decline in native songbirds in the author's neighborhood. they don't want to stick around and be constantly hassled and attacked by the more agressive species like grackles.
I rarely see a cane toad anymore, and I used to have to keep my doors closed at night to keep them out of the house, especially during the dry season.
the worldwide populations of amphibians have been declining at least as far back as the 80s. many experts feel that the depletion of the ozone layer is letting through more ultraviolet light and that these rays are having an adverse effect on this class of animals across the globe. here is the closest connection to global warming the author can make, in my opinion. but it's not necessarily the global warming that is killing these amphibians but rather the same phenomenon that is causing global warming could also be killing them. i will side with scientists on this one because they're smarter than i am, but i must admit i was always puzzled by this explanation since many amphibians, especially toads, are nocturnal and they burrow into dirt or leaf litter during the day and rarely come in contact with the rays of the sun.
I used to see a lot of blue morpho butterflies in my garden, two or three a week, but I rarely ever see them any more, just one so far this year.
huh? only two or three a week was a lot? i was in guayabo today and saw dozens of them (and, with the brilliant metallic blue flash reflected by their inner wings they are an awesome sight to see)! again, habitat destruction is leading to the loss of the plants that serve as the larval host plant for this species, so since there's no place for the blue morphos to lay their eggs they have moved on to richer, more diverse wilderness. additionally, the use of pesticides in agriculture and by the average gringo gardener probably have an effect as well because butterflies are more susceptible to these things since they're not nearly as mutative as something like a cockroach that lays a jillion eggs.
Benign snakes like bird-eaters and mosuranas are less common, but seem to be replaced by the extremely dangerous fer-de-lance, a snake once much more common in the dry lowlands.
well, i have several comments about this.
first of all, i don't know what a mosurana is. without a more accepted common name or the genus and species, i have no clue what he's talking about. it's possible that it's a regional common name given to the snake by people in that area. i asked a jungle-raised tica just now if she has heard of a mosurana and she had not.
there certainly are species of snakes that specialize in eating birds or eggs but if the native songbirds have left, only to be replaced by the urban warrior birds, these snakes (who probably don't have a strategy for hunting down grackles and cavity nesters) have probably left as well. why is that a surprise to him?
interesting that he used the obscure reference to "mosurana" but referred to the fer-de-lance by its gringo name as opposed to the country-wide accepted name "terciopelo". i'm not sure what elevation he's at, but i was at 1270 meters above sea level today in a very humid zone and saw a terciopelo (fer-de-lance). i talked to a biologist about it and he said they are very common in the area and always have been. the fact is, they're common in both dry and humid zones, and without knowing the author's elevation i can't even attempt to see if their appearance is strange. it's also quite possible that if he truly is at a higher altitude than they're found at, that he's mistaking another snake for a fer-de-lance. many snakes look alike and to the untrained observer (especially a snake-o-phobe), any snake can look like a venemous one.
The first scorpion I ever found in my house was six months back -- but I have since seen three more, of two different species. Fire ants were once rare on my property, but now, one cannot walk barefoot in the grass because of them.
more fire ants because of global warming? i doubt it. fire ants are everywhere in the tropics and subtropics. and if there is a place they aren't living it's only because they haven't found it yet but they'll get there soon. and they're another type of animal that seems to really thrive in urban areas.
and he finally just found a scorpion? they're everywhere too. and if there's any type of development going on in the area the disturbances will shake them up and cause them to be more active and look for more places to spread to.
************************
as far as the loss he's noticed of certain species and the rise in populations of others, that's something that's been going on in costa rica for decades. it's going on everywhere. sixty years ago scarlet macaws were found throughout nearly the entire country (except for the higher altitudes) and they filled the trees in places like the osa peninsula. now, they're only seen in a few scattered places and their numbers continue to dwindle. can we blame it on global warming? no. the species of ancient hardwood trees that they live in, nest in and feed from have been cut for lumber and to clear land for cattle. as this continues, you're going to see many species of animals shrink in population number and eventually go extinct.
global warming is a real danger and we need to start reversing it now. no doubt about it. but habitat destruction and pollution and the continued use of chemical fertilizers and pesticides might do away with our biodiversity before global warming even gets a chance.
|
Printer-friendly format
Email this thread to a friend
Bookmark this thread
(1000+ posts)
Send PM |
Profile |
Ignore
