Limiting Factors in an Ecosystem A look at one species: The Green Tree Frog (GTF) Hyla cineria
Limiting Factors Environmental factors (either biotic or abiotic) that prevent a population from increasing n Biotic factors are related to, caused by, or produced by living organisms. n Abiotic factors are not associated with the activities of living organisms. n Let s identify some of the limiting factors in the environment, and describe how they affect the Green Tree Frog (GTF).
Types of Limiting Factors Biotic Factors n Food description n Predation description n Disease description n Parasitism description n Invasive species description n Competition description Abiotic Factors n Water description n Living Space description n Global Warming description Combos Biotic/Abiotic Factors n Habitat Destruction description n Shelter description n Soil description
Availability of Food A basic need of all organisms to obtain energy from the environment If food is not available, organisms may not reproduce and/or may starve Green Tree Frogs eat crickets, moths, flies, other small invertebrates Biotic Factor
Water The right quantity and quality of water is a basic need of all organisms n Quantity of water: GTFs and frogs in general must have enough water to maintain the moisture in their wet/moist skins and to reproduce. n Most frogs lay their eggs in water, and need it for their tadpoles to hatch and grow. n Water Quality: is a measure of how clean the water is for the organisms that use it. n Frogs are considered good indicators of water quality since they cannot survive polluted water because of their permeable skins. n Abiotic factor
Shelter A basic need of all organisms to find a suitable place to take refuge from the weather, to hide from predators, to sleep, to raise young, etc. n GTFs prefer trees, bushes, and human houses where they consume insects attracted by light sources after dark. n Shelter may be biotic (like trees), abiotic (like rocks), and/or man made (like houses). n Abiotic/Biotic factor
Living Space A basic need of all organisms to have a certain amount of space n Sometimes called territory n Must be large enough to meet organism s basic requirements such as finding food, water, shelter, mates, etc. n Usually related to an organism s size n Abiotic factor
Predation An organism preys on and consumes animals n Green Tree Frogs are eaten by large spiders, birds, snakes, and even larger frogs (such as the invasive species Cuban Tree Frogs). n Biotic factor
Disease Viral, bacterial, and fungal infections and infected wound sites may negatively impact organisms n GTFs can be affected by various diseases n Approximately 70 species of frogs in Central and South America have been driven to extinction by a disease that is linked with global warming. n Biotic factor
Parasitism A type of symbiotic relationship in which one organism benefits and the other is harmed n Nematodes, trematodes, and other worms can infect GTFs and other organisms n May also cause deformities n Biotic factor
Invasive Species Credits: Nancy Bennett 2009 Organisms that are not native to where they are found and do harm n Invade an area and take over, pushing out native species and disrupting ecosystems n Cuban tree frogs reproduce faster than GTFs, meaning they can soon overwhelm and out number them n Cuban tree frogs have a huge appetite and eat Florida's native lizards, toads, and tree frogs, such as this unfortunate Green Tree Frog (above left). n Biotic factor
Competition Organisms compete to acquire the resources to live and reproduce successfully n Compete for food, water, shelter, space, mates, and other needs n Within their own species (other Green Tree Frogs) n With other similar species (Barking Tree Frogs, Squirrel Tree Frogs) n With unlike species (spiders and birds) n With invasive species (Cuban Tree Frogs) n Biotic factor
Global Warming One aspect of climate change which refers specifically to an increase in Earth s average surface temperature n Global warming is already causing extinctions in vulnerable species. n Scientists predict 9 52% of all terrestrial species (1 million plants and animals) will be on an irreversible path to extinction by 2050. n GTFs and other frog species are vulnerable n Abiotic factor
Habitat Destruction Loss of habitat through climate change, urbanization, and other factors n The number one reason that organisms become endangered is habitat loss n Habitats of Green Tree Frogs include wet prairies, cypress swamps, and hydric hammocks as well as borders of lakes and streams, areas with floating vegetation or moist conditions, and occasionally in brackish waters. n Biotic, abiotic and man made factors
Soil Starts out as ground up rock n Most often classified in books as abiotic n In the natural environment, the abiotic parts of soil are usually combined with organic matter (dead leaves, insects, twigs, scat). n At the beach, the abiotic sand is mixed with thousands of tiny broken shells that are biotic. n Biotic/abiotic combination
Sources n n n n n n n Nichols, M. 2008. "Hyla cinerea" (On line), Animal Diversity Web. Accessed August 15, 2012 at http://animaldiversity.ummz.umich.edu/site/accounts/information/hyla_cinerea.html Global Warming Impacts on Birds & Wildlife Copyright 2012 by National Audubon Society, Inc. All rights reserved. 13 Jun 2012.http://web4.audubon.org/globalWarming/ImpactsBirdsWildlife.php Frogs & Toads of Florida. UF Florida Wildlife Extension University of Florida http://www.wec.ufl.edu/extension/wildlife_info/frogstoads/ June2012 http://www.wec.ufl.edu/extension/wildlife_info/frogstoads/wav/green_treefrog.wav June 2012 Smithsonian (2010, November 17). Critically endangered tree frog bred for first time. Science Daily. Retrieved June 13, 2012, from http://www.sciencedaily.com /releases/2010/11/101117141520.htm. 13 Jun 2012 http://www.sciencedaily.com/releases/2010/11/101117141520.htm Habitat fragmentation Babylon Online Dictionary. Copyright 1997 2012 Babylon Ltd. Jun2012 http://dictionary.babylon.com/habitat%20fragmentation/ Pensoft Publishers (2012, August 22). Losing stream in our battle to predict and prevent invasive species. ScienceDaily. Retrieved August 28, 2012, from http://www.sciencedaily.com /releases/2012/08/120822101117.htm?_sm_byp=ivv44q075kvqfvsn