Communities (i mi/niind) 

 forest- edge: 

 biocies of, 129 



density of populations in, 129 

 life- history of bobwhite as 

 typical animal of, 142-143 

 grassland: 

 dung of larger mammals as 



microhabitat in, 125 

 grazing food coactions in, 125-128 

 lack of suitable web- building 



sites in for spiders, 124 

 life- history of meadow vole as 



typical animal of, 142 

 number of individuals per square 



meter in, 124 

 population variations of spiders 



in, 124 

 species of birds found in, 125 

 species of insects in, 124 

 species of mammals in. Table 9.3 

 species of snakes in, 125 

 structural adaptations of insects 



for living in, 125 

 toad as most characteristic 

 species of, 125 

 grouping of animals in according 



to size, 198 

 increases in fertility of, and 



changes in species composition, 

 207 

 individualistic concept of, 27 

 "influence" in, 19 

 in ponds, distinctiveness of differ- 

 ent strata of vegetation as, 81 

 in sand, characteristics of, 106- 



107 

 insect, conditions of: 

 for ants, 107-109 

 for grasshoppers, 107 

 for spiders, 109 

 major, defined. 18 

 "members" as species of less 



importance in, 20 

 merging of to form ecotone, 30 

 methods of study of food behavior 



in, 189 

 minor, defined. 18 

 more numerous constituents of 



called "predominants," 20 

 naming of on basis of geography, 



29 

 of lakes: 

 dystrophic, 66 

 eutrophic, 66 

 oligotrophic, 66 

 organismic concept of, 26-27 

 plant: 

 in floodplain, 113 

 in rock, 102-104 

 in sand, 105-106 

 naming of, 29 



principal kinds of in North 

 America, 294 



Communities (Conlnmcd) 

 stages of in clay sere, 112 

 presence of non- breeding animal 



population in, 215 

 processes in dynamics of, 155 

 productivity yield in, 207-208 

 recognition of: 

 on basis of taxonomic units, 29, 



29-30, 30 

 through dominants and predomi- 

 nants, 27 

 through physiognomy, 28 

 serai: 

 charactc r of, 26 

 species of not generally useful 

 to defining limits of biomes, 276 

 social hierarchies in, 183-184 

 strata of as cause for adaptations 



of life-forms, 8 

 subclimaxes in, 276 

 subdominants in, 19, 27 

 succession in, 21-23 

 and imbalance in energy ex- 

 changes, 207 

 as following sigmoid curve, 161 

 climatic, 23-24 

 geologic, 24-26 

 physiographic, 24 

 plant, and equilibrium with 

 habitats, 163 

 taxonomic composition of: 

 ecological equivalents in, 256 

 predominance in, 255 

 segregation of related species 



in, 255-256 

 variety of species in, 255 

 total, description of formation of 



from bare areas, 161 

 trophic levels in, 196-199 

 biomass as index to importance 

 of, 198-99 

 vegetation- types in, 28-29 

 zonation of, 313-314 

 Communities, Minor, 20 

 Community Ecology, 3, 4-5 

 Community- stands, defined. 27-28 

 Community- types, defined. 27-28 

 Competition {see also Competition, 

 Interspecific; Predation): 

 among flour beetles for micro- 

 habitats, 246 

 and specialization in feeding 



behavior in high trophic levels, 

 196-98 

 as barrier to dispersal of species, 



149 

 as cause for morphological 



adaptations, 9 

 as negligible during early coloniza- 

 tion of bare area, 255 

 as unimportant for organisms 

 whose populations are deter- 

 mined by climatic factors, 231- 

 232 



Competition (Conliniud) 

 between individuals as result of 



low population levels, 231 

 compared to predation, 182 

 defense of territories in by 

 advertisement of possession, 

 185 

 defined. 182 



difficulty of in area well-saturated 

 with established individuals, 

 183 

 direct: 

 defined. 162-183 



occurrence of among organisms, 

 182-183 

 establishment of territories as 



area of, 184 

 for food, and population density, 



222 

 for most favorable portions of 

 niche, and population density, 

 222 

 for space and population densities: 

 of birds, 221-222 

 of fish, 222 



of laboratory mice, 223 

 of plants, 221 



of sessile marine animals, 221 

 indirect: 

 defined. 182-183 

 occurrence of among plants, 183 

 in rooting of grassland vegetation, 



325 

 in serai communities, 207 

 intraspecific as keenest variety of, 

 183 

 in tropical rain forests, 345-346 

 list of effects of on animal com- 

 munity, 183 

 preadaptation to particular niche 



as advantage in, 250-251 

 reduction in: 

 aspection as factor in, 247 

 diurnation as factor in, 101, 247 

 through possession of territories 

 during breeding, 186 

 rise in: 

 with population increase above 



optimum, 175 

 with saturation of habitats, 253 

 severity of dependent on extent 

 of similarity in requirements 

 of different individuals, 183 

 social hierarchies in, 183 

 characteristics advantageous 

 for gaining high position in, 

 183 

 establishment of among house 



mice, 223-224 

 fluidity of movement through, 



183-184 

 peck orders in domestic fowl as, 

 183 

 supersedence in, 183-184 



410 Index 



