ECOLOGICAL SUCCESSION. 2~ 



mainly t<> the dying out of one set of species and (lie evolution of 

 others which take their places. 



2. Seasonal succession is the succession of species or stages in 

 the lik-hi-to;-' , ies, over a given locality, due to hereditary 

 and eni'irnnic differences in the life-histories (time of appearance) 

 of t!u- species living tht 



3. Ecolo-i. ,il succession is the succession of ecological type- 

 < phy-iolo-u ,il t\ ]!(-. modes of life) over a given point or locality. 

 duetochai >f environmental conditions at that point. From 

 thi- point (' \ie\v untiring to do with 5/>< \-cept that 

 )innii\ an- necessary. There are of rour-e relation- hetweeii 

 the-, three phenomena hut the-e relation- are of the nature 

 of rh-ek- in method of -tudy rather than e eiitial-. ami -pace 

 will not permit US to disCUSS them here. Tin re are al-o qualifi- 

 cation- of a -imilar nature that might IK- made to the 

 delinilii'ii-. \\iili me to the -tatemeiit thai Species 

 are inel.-\anl to the que-tion. a \\ord -hould he added. If the 

 hahit- of a spe< part "I the delmitioii ot that species, 

 a- the\ iiui-l -ooiier "i later conn- (o In-, tlu-n -peeie- an -i^nili- 



( -am . The definition applies to the manner in \vhirh the spe< ies 



(|lle-tioll i- Healed ill ]ir.ieli' 



\\ . ha\e noted the migration a-|iett of t In- relai ion .>t \\-\\ in 

 -mall -iieam-. ^ne e--i< 'ii i- Imt a dittereiit jioint ot \ie\\. 

 ^nei e--ioii of ii-h mean- succession of e-i.iMi-hed torm-. ;. -.. 

 I fi'iin- that make tl tin their regular al>ode. The mo-t 



ini|)oitallt a-|nel ..| --t al ili-hlllellt i- hreedillg. AnumluT of 



\\riter-ha\edi-iu--ed the breeding habits of the -pet ie- toiind 



in the-e -mall streams I ig< nmann, '^5; l ; orlu - and l\ii hard-on. 



I Ian kin-oii. '..7. 'lO; \<> i-^hanl. ' ' s . Reeves, '07 : ^iniih. '( 



:!ctncn( OJ /' x Jm. 



>ui-et---inii in tin efon u- i- a ret i >n-i met ii m. It i- 



1-a-ed on the -uperpo-ition of all the fi-h communities o\er ihe 

 olde-t part of the olde-t and large-t -tn-.tm. To make this 

 clearer, \\ e will -late with the aid of the diagram I ig. 4 the 

 -ucce--ion of li-h in Bull Creek. Thi- -inve ion \\ill he < -on- 

 >idered a- taking place over the olde-t jtart of the portion of 

 Hull Creek \\hich lie- hack of the hluff of the former and higher 

 lex el- of Lake Michigan. Thi- i- the point de-ignaied a- 5. 



