Disturbance of plateau zokor-made mound stimulates plant community regeneration in the Qinghai-Tibetan Plateau, China

Mounds constructed by plateau zokors,which is widely distributed in alpine meadows significantly modified plant community structure.However,the variations of plant community structure under the disturbance of plateau zokor-made mound are less concerned.Therefore,we investigated the responses of plant community on zokor-made mound of different years(1 a and 3-4 a),and compared with undisturbed sites(no mound)in an alpine meadow in the eastern Qinghai-Tibetan Plateau(QTP),China.Species richness,coverage and Simpson diversity index were all significantly reduced by the presence of zokor-made mound,but plant heights were significantly increased,particularly in grasses and sedges.Several perennial forage species showed an increased importance value and niche breadth,including Koeleria macrantha,Elymus nutans and Poa pratensis.The effect of zokor-made mound on niche overlap showed that more intense interspecific competition produced a greater utilization of environmental resources.And this interspecific niche overlap was strengthened as succession progressed.The bare mound created by zokor burrowing activities provided a colonizing opportunity for non-dominant forage species,resulting in abundant plant species and plant diversity during the succession period.We concluded that presence of zokor-made mound was conducive to regeneration and vitality of plant community in alpine meadows,thus improving their resilience to anthropogenic stress.

Influence of aerial seed banks on germination response in three desert plant species

Aims To determine if the germination response of desert plant species to a period of aerial storage in field conditions(i.e.mature seeds that remain attached to the parent plant)is comparable to seeds harvested at maturity and stored in ambient laboratory conditions,to better understand the role of aerial seed bank in the germina-tion ecology of desert plants,using one annual and two perennial species.Methods Seeds of three desert plants(Anastatica hierochuntica,Blepharis ciliaris and Scrophularia deserti)that matured in June 2014,were collected from wild plants in June and November 2014,and ger-minated under two photoperiods(0,12 hours light)and three ther-moperiods(night/day temperatures of 15/25,20/30 and 25/35°c).Important Findings Seeds of B.ciliaris and S.deserti had significantly higher germination percentages when harvested and stored for five months,compared to being stored in the aerial seed bank.Germination percentages of these two species increased with decreasing temperature and in the presence of light.These results indicate that these species use a com-bination of aerial and soil seed banks to maintain a percentage of viable seeds through favourable germination periods.Germination percentages of A.hierochuntica were high under all tested circum-stances,indicating that this species relies mainly on the aerial seed bank to maintain a percentage of viable seeds through favourable germination periods.This study shows that the population survival strategies of an aerial seed bank are species-specific.These results have practical implications for conservation and habitat restoration for these species,and also for their propagation since early collec-tion of mature fruits and ex situ storage will result in greater germi-nation percentages of some species.

深圳大沙河生态长廊

深圳的大沙河,发源于羊台山,纵贯深圳市南山区,全长13.7km,是一条传承着南山记忆的"母亲河",承载着周边居民的儿时美好回忆。然而,随着城市快速推进,大沙河两侧绿地逐步收紧,历经几次工程化改造之后由自然河川转变为了以城市排洪调蓄为主的功能性"渠道";随着经济的迅速发展及人口的急剧增加,大沙河接纳的污染负荷远远超过其自净能力,致使污染程度急剧增加,河水发黑、发臭。居民也渐渐忘却了伴水而居的乐趣,河道也不再与城市有任何对话。大沙河是深圳"四带六廊"基本生态格局中山脉支撑带(羊台山–梧桐山中部山脉)和滨海生态带之间的重要生态走廊。在大沙河的全面提升中,项目组秉持了生态优先的基本理念,在规划中采取了多角度的考量,务求寻找到一条综合解决之道,在确保大沙河的城市防洪功能的基础上,通过景观缝合碎片化的都市生态。