退化 become vestigial; degenerate; deteriorate; retrograde; devolution; retrogradation; retrogression; retroversion; regression; involution; degeneration; degenerescence; degeneracy; cataplasia; catagenesis; atresia 鸡的翅膀逐渐退化, 不会在空中飞行了。 the wings of the chicken have become vestigial; it can no longer fly. 土豆种了几年之后就会退化。 after a few years' planting, the quality of the potato crop deteriorates
The disaster of drought and waterlog is severely and frequently , the water and soil loss and rock desertification is increasing , the subsidence is happened at some ground , the bio - diversity decrease , the vegetation and soil evolve conversely , the productivity declines , the people lives in difficulty , and the most phenomenon and types of ecological problem are concentrated in karst area . to strengthen studies on karst ecological characteristics and degradation types can provide gist for ecological rehabilitation and reconstruction in karst area , but also can provide means for reference for other ecology area 严重而频繁旱涝灾害、水土流失、石漠化现象加剧、地面塌陷、生物多样性丧失、植被与土壤出现逆向演替、生产力水平降低、人居生活困难等,集中了全球生态问题的主要表现和主要类型;因此,加强对岩溶区生态特征和退化类型的研究,不但能为岩溶区生态的恢复和重建提供依据,也为其它生态区的研究提供方法借鉴。