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Biggest impacts on fish/plants/etc...


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#1 Guest_factnfiction101_*

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Posted 21 January 2009 - 09:14 PM

I was wondering what has been some of the biggest impacts on fish/plants/etc... that were caused by mankind (directly or indirectly)? I know it's a pretty broad question :( But if you could run down a few of them, or give me a good link to a page, I'd appreciate it a lot.

What types of pollution, chemicals, etc... has created problems also?

This information is for the game that I've been working on.

Edited by factnfiction101, 21 January 2009 - 09:20 PM.


#2 Guest_ashtonmj_*

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Posted 21 January 2009 - 09:35 PM

How long of a list are you looking for...because it's really long.

#3 Guest_factnfiction101_*

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Posted 21 January 2009 - 09:44 PM

How long of a list are you looking for...because it's really long.

As long of a list as you can make, or just the biggest impacts that you can think of, that come to mind... w/e you got.

#4 Guest_Newt_*

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Posted 21 January 2009 - 09:47 PM

One big one to start off with: stream alteration. Damming, dredging, channelization, interdrainage canals. Huge effects on habitat, dispersal corridors, flow regimes, etc., etc.

#5 Guest_factnfiction101_*

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Posted 21 January 2009 - 10:12 PM

One big one to start off with: stream alteration. Damming, dredging, channelization, interdrainage canals. Huge effects on habitat, dispersal corridors, flow regimes, etc., etc.

Thanks, I forgot about damming. I remember a topic here about a channel being cleaned out because it was causing problems to some farmers or something.

I googled "impacts of damming" found a article on wikipedia, then discovered at the bottom a list of Environmental issues. Looking through that currently...

#6 Guest_Kanus_*

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Posted 21 January 2009 - 11:38 PM

Nitrates, phophates, sediment/erosion, synthetic estrogens, heavy metals, oil spills...um...oh yeah, fly ash waste too!

Introduced species, esp. salmonids, micropterus, zebra mussels, round gobies...

#7 Guest_rjmtx_*

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Posted 21 January 2009 - 11:49 PM

The thing is, the magnitude of different problems are specific to what body of water you're referring to. For instance, some rivers are somewhat resistant to fish invasions because of flow regimes, ecology, etc. Other rivers can be devestated by invasion at a drop of a hat. Often the problems are compounding, where alone they might not have that great of an effect. Take Western US streams. They historically have reliable, but extreme flood/drought cycles. Drop a fish in that's adapted to a low gradient, wet environment, and it probably won't be able to become established in such an extreme river. Throw a dam in that will lower flood frequencies and levels and raise flows during times of drought, thus normalizing the flow, the invasive fish takes off as the native fish adapted for extreme flows taper off into oblivion.

There are a lot of other aspects to stream alteration, which also vary regionally. Fish passage barriers are a big deal in streams with migratory fishes, but probably won't have that large of an effect on, say, mosquitofish.

Pollution's a whole 'nother bag of worms. Overharvest can be a factor, too (for US freshwater, that was a biggie in the past). Land alteration. Reduced access to terrestrial food items. Increased nutrients. On and on.

In Texas, a good deal of our ecological problems stem from a complex system of reservoirs which makes it tough for the river and reservoir folks to see eye-to-eye on a lot of issues. This is a state with one (semi)natural lake and 150+ named reservoirs. Lake people rarely care too much about the well-being of a shiner grumble, grumble...

#8 Guest_factnfiction101_*

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Posted 22 January 2009 - 05:39 PM

Thanks Kanos :D I knew Zebra Mussels were a problem in the Great Lakes, but I'll look into the other things you mentioned.

Thanks for your interesting post rjmtx, that clears up questions I had about damming. I can see why damming is more of a problem than I thought. I've wondered why parts of the west doesn't have more species of fish.

#9 Guest_fundulus_*

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Posted 22 January 2009 - 06:33 PM

In truth, the western part of North America had low fish diversity for a variety of long-term geologic reasons. But damning the rivers and overpumping ground water has been a one-two punch to that original diversity, different ways to alter and destroy habitat which is truly the big killer.

#10 Guest_rjmtx_*

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Posted 22 January 2009 - 09:22 PM

All-in-all the state of our waters sucks. On the bright side, it's job security for me.

#11 Guest_factnfiction101_*

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Posted 25 January 2009 - 06:29 PM

I'm not sure about the effects of synthetic estrogens, heavy metals, and reduced access to terrestrial food items (I'm guessing you mean fish not being able to reach their normal food supply? I don't understand how that works or could work) hurt fish.

What are some little known invasive fish/plants/etc... ? I've read through the forum in the past few days and it seems like Carp, Rusty Crayfish, Zebra Mussels, Blue Tilapia, Oscar, Eurasian Ruffe, Purple Loosestrife, Spiny water flea, walking catfish, snakehead, Asian Swamp eel, Didymo, Duckweed, and Water Hyacinth. A few of those came from a Great Lakes website or other sources. Info on invasive species in the everglades/Florida would be very helpful also.

I've seen attitudes change about snakeheads (on the forum), are they still a big problem? Or do they receive more attention than other things?

What other types of treatment do they treat the river/lakes with, other than Lampreycide? Also does Black Fly spray hurt fish or animals?

What fish have been overharvested? I know Blue Pike were, in the Great Lakes.

In a river or lake that's being polluted, what are the first to go? The first signs.

#12 Guest_fundulus_*

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Posted 25 January 2009 - 07:42 PM

The first organisms to go in a progressively polluted aquatic ecosystem are the insects and molluscs. That simplifies or destroys the food web, so fish that can survive the physical stress of pollutants don't have food, and their young are probably deprived of the right-sized foods.

Synthetic estrogens can be surprisingly effective at taking out a wide range of animals. Besides the more graphic effects of feminized males with diminished capacity/interest in reproduction, many synthetic estrogens can confuse fishes' olfaction and thereby diminish reproductive success. With most pollutants it all gets back to shutting down successful reproduction. Many populations of freshwater mussels are living relicts; they'll live a long time, but because of environmental alteration they've either stopped trying to reproduce, or their offspring fail year after year, and eventually the adults die and that's it.

Acidified ponds are beautiful with clear water. But they're dead zones for most fishes as time goes on and reproductive success remains zero.

#13 Guest_CATfishTONY_*

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Posted 25 January 2009 - 08:58 PM

[quote name='factnfiction101' date='Jan 25 2009, 05:29 PM' post='53039']
Info on invasive species in the everglades/Florida would be very helpful also.



http://myfwc.com/nonnatives/

#14 Guest_factnfiction101_*

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Posted 26 January 2009 - 10:59 AM

Thanks a lot for that explanation fundulus :D Yeah, I think my cousins uncle had a pond that became really acidic (or something happened to it). I caught bluegill there, and it was the first time that I had ever seen a snapping turtle.


Info on invasive species in the everglades/Florida would be very helpful also.

http://myfwc.com/nonnatives/

Funny thing is, I've been to that site before :mellow: I'm so forgetful :(

Edited by factnfiction101, 26 January 2009 - 11:00 AM.


#15 Guest_nativeplanter_*

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Posted 26 January 2009 - 03:06 PM

Development in headwaters is a major problem. Since the amount of land surrounding a small tributaty has a much higher land:water ratio than does the land surrounding a larger river. Removal of the forestland (or prairie, etc) and replacing it with homes and businesses changes the amount of water flowing in the stream, its timing, adds chemicals and fertilizers from runoff, changes the supply of sediment, alters stream temperature, removes land organisms that normally play a role in stream processes (such as leaf fall and woody debris, as well as animals).

Most people understand the impacts of filling wetlands and ephemeral streams. But few understand the magnitude of the impact from development in general. Non-point sources of pollution (e.g. from runoff) now account for more pollution in streams than point sources (like that from outfalls), since point sources are now (generally) regulated. While agricultural practices sure can have impressive impacts (especially cattle), the impacts from development are far-ranging.



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