First, find out about threats to your eco-system.  List the exact terms you may need to search.

Natural Communities of Wisconsin
http://dnr.wi.gov/org/land/er/communities/
 --Inland Lakes
    http://dnr.wi.gov/org/land/er/communities/index.asp?mode=detail&Code=C5

 --Wetlands
    http://dnr.wi.gov/org/land/er/communities/index.asp?mode=group&Type=Wetland

 --Open Bog
    http://dnr.wi.gov/org/land/er/communities/index.asp?mode=detail&Code=CPSHR054WI

 --Dry Prairie
    http://dnr.wi.gov/org/land/er/communities/index.asp?mode=detail&Code=CTHER070WI

 --Southern Wisconsin Forest
    http://dnr.wi.gov/org/land/er/communities/index.asp?mode=detail&Code=CTFOR044WI

Grzimek's Animals Database
This database allows you to look in Biomes;  see if there are threats listed under your biome.
infotrac.galegroup.com/itweb/waunakeecommsch?db=GZAL

Next, find articles about a threat to your eco-system. 

EbscoHOST
http://www.badgerlink.net/
Go to the High School LMTC WebPage> Select "Enter EBSCO from School" >  Choose "Database List." Place check marks by the following:  Academic Search Premier, GeenFILE,  MAS Ultra School Edition,  MasterFILE Premiere,  Newspaper Source Plus, and Science Reference Center.  Select "Continue."  Begin your search.  Make sure to include your eco-system and a specific threat.  Try different search terms.

Fact on File Science Online
Choose "Science Online" in the next screen.  Search on the name of your eco system and include the name of the problem.  Example:  Rivers AND  runoff
Enter Science Online from SCHOOL   
Enter Science Online from HOME  (Need Username and Password) 

Additional Information on your organism:

Animal Diversity Web
http://animaldiversity.ummz.umich.edu/site/index.html
GOOD ONLY FOR ANIMALS! Try both your organism's common name and its scientific name.

FishBase
http://www.fishbase.org/
GOOD ONLY FOR FISH! Works best with scientific names (genus AND species, spelled correctly).

Cornell Lab of Ornithology -- All About Birds
http://www.birds.cornell.edu/AllAboutBirds/BirdGuide/
GOOD ONLY FOR BIRDS (and only for some American birds)! Only works with common names.

Plant Database -- USDA
http://plants.usda.gov/
Can search by scientific name (try that first). Scroll down for compleate information.