《群落的動態(tài)》ppt課件-全文預(yù)覽
【正文】 底抬升 ? 直立水生階段：湖底大大變淺，挺水植物如蘆葦?shù)热〈∪~根生植物，使湖底迅速抬高 ? 濕生草本植物階段：喜濕生的沼澤植物出現(xiàn)，如莎草科和禾本科中的濕生種類 ? 木本植物階段：木本灌木出現(xiàn)，然后喬木出現(xiàn)，形成森林 Succession in stream munities ? Rapid succession has been well documented in Sycamore Creek, Arizona, which has been studied for nearly two decades by Stuart Fisher and his colleagues (1982) ? The creek is a tributary of the Verde River, lies approximately 32 km northeast of Phoenix, Arizona, where it drains approximately 500 km2 of mountainous desert terrain. ? Evaporation（蒸發(fā)） nearly equals precipitation（降雨量） within the Sycamore Creek catchment, so flows are generally low and often intermittent. ? However, the creek is subject to frequent flash floods with sufficient power to pletely disrupt the munity and initiate succession Succession in Sycamore Creek after floods ? Two days after floods, the majority of the stream bottom consisted of bare sand with some patches of diatoms ? Five days after floods, diatoms covered about half the streambed ? Within 13 to 22 days, diatoms almost pletely covered the stream bottom, other algae, especially bluegreen algae and mats consisting of a mixture of the green alga Cladophora and bluegreen algae, appeared in significant quantities by day 35 ? By day 63, the bottom of Sycamore Creek consisted of a patchwork of areas dominated by diatoms, bluegreen algae, and mats of Cladophora and bluegreen algae ? The diversity of diatoms and other algae, as measured by H’, leveled off after only 5 days, and then began to decline after about 50 days ? Most macroinvertebrate species survived the flood, because the invertebrate munity of the creek is dominated by insects whose adults are terrestrial, during the floods of August, many adult insects were in the aerial stage and the flood passed under them, these adults were the source of most invertebrate recolonization of the flooddevastated creek Algal species diversity during succession in Sycamore Creek, Arizona (data from Fisher et al. 1982) 旱生演替系列 Xerosere ? 地衣植物群落階段：巖石表面無土壤，光照強，溫度變化大，貧瘠而干燥，最先出現(xiàn)地衣，分泌的有機酸腐蝕巖石，加上自然的風(fēng)化，巖石表面出現(xiàn)含有機質(zhì)的小顆粒，并逐漸增多 ? 苔蘚植物群落階段：地衣群落后期開始出現(xiàn)苔蘚植物，能忍受極端干旱環(huán)境，生長可以積累更多的腐殖質(zhì)，對巖石表面的改造作用更強烈，巖石顆粒變細小，松軟層更厚，為土壤的發(fā)育和形成創(chuàng)造條件 ? 草本植物群落階段：一些耐旱的高等植物侵入，對環(huán)境改造更強烈，小氣候和土壤條件更有利于植物的生長 ? 灌木群落階段：一些喜陽的灌木開始出現(xiàn)，常與高草混生 ? 喬木群落階段：喜陽的樹木增加，逐漸形成森林，最后形成與當(dāng)?shù)貧夂蛳噙m應(yīng)的喬木群落，形成頂級群落 群落初生演替經(jīng)歷的地衣階段 、苔蘚階段 、 草本植物階段 、 灌木階段和森林階段 Secondary succession in temperate forests Succession of plant species on abandoned fields in North Carolina. Pioneer species consist of a variety of annual plants. This successional stage is then followed by munities of perennials and grasses, shrubs, softwood trees and shrubs, and finally hardwood trees and shrubs. This succession takes about 120 years to go from the pioneer stage to the climax munity Succession in rock intertidal munities ?
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