INTRODUCTION
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BIOL 3240 Plant and Animal Ecology – Distribution & Abundance Introduction • Ecologists usually define a population as… – Characterized by the number of individuals and their density. • Additional characteristics of a population include… 1 BIOL 3240 Plant and Animal Ecology – Distribution & Abundance Distribution Limits • _____________________ limits geographic distribution of a species. – Organisms can only compensate so much for environmental variation. 2 BIOL 3240 Plant and Animal Ecology – Distribution & Abundance Niches • _______: Summarizes environmental factors that influence growth, survival, and reproduction of a species. – Grinnell’s definition focused on the effects of the physical environment – Elton’s definition included biotic and abiotic factors 3 BIOL 3240 Plant and Animal Ecology – Distribution & Abundance Niches • Hutchinson defined niche as: – • n equates the number of environmental factors important to survival and reproduction of a species. – ___________________- hypervolume – ___________________ includes interactions such as competition that may restrict environments where a species may live. 4 BIOL 3240 Plant and Animal Ecology – Distribution & Abundance Kangaroo Distributions and Climate 5 BIOL 3240 Plant and Animal Ecology – Distribution & Abundance Tiger Beetle of Cold Climates • Tiger Beetle (Cicindela longilabris) lives at higher latitudes and elevations than most other species in NA. – Schultz et. al. found metabolic rates of C. longilabris are higher and preferred temperatures ____________ than most other species. • Supports generalization that the physical environment limits species distributions. 7 BIOL 3240 Plant and Animal Ecology – Distribution & Abundance Tiger Beetle of Cold Climates 8 BIOL 3240 Plant and Animal Ecology – Distribution & Abundance Distributions of Plants Along a MoistureTemperature Gradient • Encelia species distributions correspond to variations in temperature and precipitation. 9 BIOL 3240 Plant and Animal Ecology – Distribution & Abundance Distributions of Barnacles Along an Intertidal Gradient 10 BIOL 3240 Plant and Animal Ecology – Distribution & Abundance Distributions of Barnacles Along an Intertidal Exposure Gradient • Organisms living in an intertidal zone have evolved to different degrees of resistance to… – Barnacles show … • Connell found Chthamalus stellatus restricted to upper levels while Balanus balanoides is limited to middle and lower levels. 11 BIOL 3240 Plant and Animal Ecology – Distribution & Abundance Distributions of Barnacles Along an Intertidal Gradient • Balanus appears to be more vulnerable to _____________, excluding it from the upper intertidal zone. • Chthamalus adults appear to be excluded from lower areas by _____________ with Balanus. 12 BIOL 3240 Plant and Animal Ecology – Distribution & Abundance Distribution of Individuals on Small Scales • _____________: Equal chance of being anywhere. – • _____________: Uniformly spaced. – – • _____________: Unequal chance of being anywhere. – – 13 BIOL 3240 Plant and Animal Ecology – Distribution & Abundance Distribution of Individuals on Small Scales 14 BIOL 3240 Plant and Animal Ecology – Distribution & Abundance What pattern? Why? http://soundwaves.usgs.gov/2004/11/NestingColonyLG.jpg 15 BIOL 3240 Plant and Animal Ecology – Distribution & Abundance What pattern? Why? http://i.telegraph.co.uk/telegraph/multimedia/archive/01216/gnu_1216499c.jpg 16 BIOL 3240 Plant and Animal Ecology – Distribution & Abundance Species of aggressive stingless bees that forage over clumped resources… how would you predict they be distributed? How about passive species foraging on regularly spread resources? http://farm3.static.flickr.com/2359/2459405670_f8082401c0.jpg 17 BIOL 3240 Plant and Animal Ecology – Distribution & Abundance Distribution of Tropical Bee Colonies – As predicted, four species with regular distributions were highly aggressive. • Fifth was non-aggressive and ___________ distributed. • Prospective nest sites marked with ____________. 18 BIOL 3240 Plant and Animal Ecology – Distribution & Abundance Distributions of Desert Shrubs • Traditional theory suggests desert shrubs are regularly spaced due to competition but…. 19 BIOL 3240 Plant and Animal Ecology – Distribution & Abundance Organism Size and Population Density Density decreases as body size… How does aquatic invertebrate density cmopare to that of other animals of comparable size? How does mammal density compare to bird density? 26 BIOL 3240 Plant and Animal Ecology – Distribution & Abundance Plant Size and Population Density • Plant population density ___________ with ____________ plant size. – Underlying details are very different. • 27 BIOL 3240 Plant and Animal Ecology – Distribution & Abundance Commonness and Rarity • Rabinowitz devised commonness classification based on (3) factors: • • • • Populations that are least threatened by extinction, have extensive geographic ranges, broad habitat tolerances, and some large local populations. – All seven other combinations create some kind of rarity. 28 BIOL 3240 Plant and Animal Ecology – Distribution & Abundance Rarity • Rarity I – • Peregrine Falcon http://falconrytoday.net/news/wp-content/uploads/2009/08/Peregrine-Falcon0014.jpg • Rarity II – • Passenger Pigeon http://www.saroffillustration.com/portfolio/page/ns4_pigeon.jpg 29 BIOL 3240 Plant and Animal Ecology – Distribution & Abundance Rarity • Rarity III – • California Condor http://www.dfg.ca.gov/wildlife/hunting/condor/images/condor119.jpg 30
