化石群落的演替

化石群落的演替是指在外界环境保持稳定或促进之下,由群落内部物件间相互作用而导致该群落内部生物间的相互变化。它也具有平均时间的性质。四川龙门山区白柳坪组Orientospirifer-Neoathyrisina~1)群落的演替过程表明,化石群落的演替过程是可以保存下来的。对它的研究有利于提高地层划分的精度,有利于古环境的恢复和再造,时研究生物进化也很有益处。演替和取代的最大区别在于后者主要由外界自然条件变更而引起一个群落向另一个群落的更迭。

THE SUCCESSION OF Orientospirifer-Neoathyrisina COMMUNITY FROM THE EARLY LOWER DEVONIAN OF LONGMENSHAN AREA, SICHUAN

Ecologic succession of community is the means of community change afterthe first sets of organisms (opportunistic species) invade a newly created orrecently vacated habitat until to something resembling a local steady-statecondition in organism-organism and organism-environment interactions arereached. Some scientists believe that, the process of paleocommunity is can'tpreserved in fossils or studied using geologic samples, because, it is very shortperiod in the time scale (in genenal, 10--20 years for a fauna community, and50--100 years for a flora community) and is controlled largely by its own variedspecies interactions in this community and not by the physical environments.In this paper, it is discusssed that the process of ecologic succession of Oriento-spirifer-Neoathyrisina paleocommunity from the Early Lower Devonian BailupingFormation Longmenshan Area, in which, the Prochoneles bailupingensis, Chonetescf. ellip?icus etc. are as opportunistic species, the Neoa?hyrisina. Ps?udoa?hyrisina,Para?hyrisina etc. are as equilibrium species and the Orien?ospirifer, Howellella.Acrospirifer etc. are as ubiquitous species. According to this process of succession as discussed in this paper, thesuccession of paleocommunity can be preserved in fossils and can be studied bypaleontologists. Because the succession of paleocommunity has time-averuged concept. aodalso, each stage of the succession has time-averaged concept, too.