Pond and Marsh Management 



(Continued) 

 control of mosquitoes in, 92 

 control of turbidity in, 91 

 control of water level in, 91 

 increasing fertility of vegetation 



in, 91 

 prevention of disappearance of 



habitat through succession, 91 

 stocking prey- predator combina- 

 tions of fish, 91 

 Ponds {see Biocies, Pond- Marsh): 

 acidity of, 79 



activity of life in during winter, 87 

 animal sere in, 81 

 artificial, construction of, 91 

 benthic production in and presence 



of fish, 91 

 biomass and food habits of fish 



species in, 91 

 biomass of and fertility, 90-91 

 biomass of fish in, 90-91 

 biomass of invertebrates in shallow 



water of, 90 

 changing of eutrophic lakes into, 



102-104 

 characteristic species of, 96 

 defined. 79 

 drought 'in and spores resistant to 



desiccation, 87-88 

 freezing of in tundra biome, 315 

 icy, mortality of fish in, 87 

 in alpine tundra, fauna of, 322 

 life- histories of principal pond 



organisms, 88-90 

 mature, characteristics of bottoms 



of, 79 

 occurrence of in grassland, 330 

 of desert, distinct nature of fish 



in, 239 

 organisms of in arctic tundra, 319 

 oxygen content of and photosynthe- 

 sis, 79 

 oxygen content of and seasons, 79 

 periphyton as food source in, 87 

 pH values of, 79 

 predators in, 87 

 productivity of fish in indicated 



by biomass harvested, 91 

 productivity of vertebrates other 



than fish in, 91 

 shrinkage of in summer, 87 

 stages in hydrosere of, 79-81 

 temperatures of, 79 

 temporary, egg-laying in by frogs 



and toads, 88 

 temporary, inhabitants of, 88 

 variations in oxygen content of in 



day and night, 79 

 young characteristics of bottoms 



of, 79 

 Population Dynamics, growth of as 



branch of ecology, 5 



Population{s) {see also Catastrophes; 



Cycles; Ecesis; Isolation of 



Populations; Measurement(s) of 



Populations; Sea; Variation(s) 



in Population Characteristics); 

 average or regional density in, 



defined. 219 

 abeyance of stablizing factors in 



after catastrophes, 232 

 age ratios in after catastrophes, 



216-217 

 as affected by breeding ages of 



animals, 215 

 as influenced by abundance of 



seeds, 192 

 average ratios of from years to 



years, 234 

 biomasses of in ponds, 90-91 

 characteristic levels of for 



species, 219-220 

 climatic and biotic factors in size 



of for rose thrips, 231-232 

 competition as stablizing factor in: 

 amount of food available and, 222 

 close growth of sessile marine 



animals and, 221 

 defense of territories by birds 



and, 221-222 

 food supply of fish and, 222 

 plant struggle for space and, 221 

 struggle for most favorable 



portion of niche and, 222 

 control of in pond and marsh 



management, 91-92 

 cooperation and disoperation in 



growth curves of, 219-220 

 densities of hosts and reproduc- 



tivity of parasitoids, 226-227 

 density-dependent factors in, 



defined. 220-221 

 density- independent factors in 



acting as density- responsive, 



230 

 density- independent factors in, 



space, weather and food as, 230 

 density of in forests, and stratifi- 

 cation, 136-137 

 density- stabilizing factors in 



described as biotic, 220 

 depletion of by catastrophes, 235- 



237 

 difficulty of developing methods 



for measurement of, 2 

 difficulty of measuring except 



with restricted distribution, 219 

 disease as stablizing factor in, 



228-229 

 distinguishing between passive 



density-responsive effects and 



dynamic density-dependent 



effects in, 230 

 distinguishing young from adults 



in, 216 



Population(s) (Continued) 



distribution of in inner zone of 

 normal abundance, 233 



distribution of in zone of occa- 

 sional abundance, 233 



distribution of in zone of possible 

 abundance, 233 



economic or habitat density in, 

 defined. 219 



effects of competition in on other 

 life processes, 222 



evaluation of species through 

 abundance of, 20 



existence of density-limiting 

 factors in, 229 



factors determining regional 

 densities of, 219 



factors in differences of levels 

 in, 219 



factors in production of asymptote 

 in, 220 



fluctuations in ratios of and errors 

 of sampling, 234 



fluctuations in with predation, 

 196 



forest and luxuriance of vegetation 

 m forests, 138 



growth curve of and productivity 

 yield, 207-208 



high level of in ground animals 

 in forests, 137 



hyperparasitoidism as form of 

 control of, 182 



importance of variability in 

 factors affecting, 231 



increase in predation with density 

 of prey as density- stablizing 

 factor in, 225 



increase in with progression of 

 clay sere, 112-113 



increases in parasitoidism due to 

 temperature, 227 



individual variations in reactions 

 to factors controlling and need 

 for combined action of factors, 

 231 



in grasslands from which preda- 

 tors have been eliminated, 128- 

 129 



in ponds during different seasons, 

 87 



in streams, 43-44 



intercompensations between com- 

 petition and predation in, 231 



inverse effects of density-depend- 

 ent factors in, 220-221 



inverse relation in between number 

 of species and number of indi- 

 viduals per species, 255 



kinds of variations in, 234 



level of and overgrazing, 128 



level of in relation to number of 

 species and predation, 226 



434 Index 



