1 Overview a Island i Examples 1 Oceanic island 2 Ecologically might mountain tops work like islands a Rocky state park no vegitation dominated by shrubs and herbacious plants at top of mountain heath ball its called 3 Local Patches 4 Any spatially isolated community can act as an island b Preston 1962 i Lead up to mccarson ii He formalized species area curves 2 Species area relationships a First thing we do is sample areas of different sizes b Count the number of species in each area c Plot number of species dependent variable vs area independent varable d The result is larger areas show more species e Species area equation preston put together i S cAz ii S number of species iii c a constant depending on group and unit of measurement 1 Depends on taxonomic group and unit of measurement iv A area of island v Z slope of line relating S and A vi Rearrange equation 1 log S log cAz 2 log S log c log Az 3 log S log c z log A 4 Treat log S as y 5 Treat log C as b 6 Treat z log A as mx f Species area relationships on mainland s i log log plot is linear over many area sizes ii Slope is typically below 0 24 iii There aren t that many new species to add as the pool increases in main land g Species area relationships on islands i log log plot is linear ii Slope is higher than from mainlands iii Islands are species poor depauperate iv Barriers to dispersal make it so there are fewer species on islands v Fewer of the mainland pool gets to islands vi As we increase area there are many more additions possible as area increases on islands 3 Equilibrium model a MacArthur and Wilson 1967 same MacArthur as all other things i The Theory of Island Biogeography b c d e f This book marked the start of modern community ecology Sought to explain why island diversities differ Think of birth and death rate model when thinking of this model Predicts turnover of island species membership habitat hypothesis does not predict turnover