鼠类对山杏种子存活和萌发的影响

Effect of rodent predation on seedling survival and recruitment of wild apricot

山杏 (Prunus armeniaca)是广布于北京山区阳坡的矮林或灌丛 ,易生存在土壤贫脊、干旱、或严重退化的山坡、裸地 ,对于保护生态环境 ,减少水土流失及促进山区经济发展均具有重要作用。有关鼠类在山杏更新中作用的研究较少 ,本研究主要是确定影响山杏更新的鼠类种类、鼠类对山杏种子的取食压力、人工埋藏种子及植被因素对种子存活和萌发的影响。于 1 997年 1 0月 3～ 4日 ,采用夹捕法同时调查取食花生和山杏种子的鼠类种类及种群密度。于 1 997年 9月 2 4～2 5日 ,通过在地表放置山杏种子 ,调查在鼠类取食下 ,地表种子消失的速度。于 1 997年 1 0月 2 0日 ,作种子埋藏实验 ,调查种子存活及萌发情况。于 1 997年 1 0月 2 6日 ,进行扣网实验 ,研究网内、外山杏种子存活及萌发情况。结果表明 :大林姬鼠 (Apodemus speciosus)、社鼠 (Rattus confucianus) ,黑线姬鼠 (Apodemusagrarius)为取食山杏种子的主要鼠种种类 ;与取食花生相比 ,社鼠更偏爱山杏种子 ,大林姬鼠对山杏种子喜食性略低 ,黑线姬鼠对二者喜食程度相近 ;山杏种子放置地表后 1、1 0、2 0、3 0 d的消失率分别为 1 3 .0 6% ,64 .4 6% ,90 .70 % ,96.69% ;扣网实验说明 ,山杏在地表的萌发率极低 ,生长也慢 ;

Wild apricot ( Prunus armeniaca ) low forests or shrubs are widely distributed in sunny slopes of mountains in Beijing. Wild apricot survives in very harsh dry environments with poor soil or in degenerated hills, so it plays an important role in conserving environments and reducing soil erosion as well as facilitating economic development in the undeveloped countryside. Few attempts were made to study the interaction between rodents and apricot. This study aims to identify rodent species of removing apricot seeds, seed disappearance under rodent predation, and effects of burial and wire mesh cover on seedling recruitment. On October 3～4, 1997, wooden snare traps baited with peanuts and apricot seeds were used for identifying rodent species of removing apricot seeds. Seed removal was studied by placing apricot seeds on surface between September 24~25, 1997. Seed survival and seedling recruitment were studied by burying apricot seeds 5 cm deep in soil on October 20, 1997, and also by using wire meshes on October 26,1997. Apodemus speciosus, Rattus confucianus, Apodemus agrarius were identified to be seed\|eaters of apricot. R. confucianus preferred apricot seeds to peanuts. The other species showed little difference in food preference between apricot seeds and peanuts. The removal proportions of seeds within 1, 10, 20, 30 days were respectively 13.06%, 64.46%, 90.70% and 96.69% after seed placement on surface. The seedling recruitment was lower when seeds were placed on soil surface and protected in wire meshes than that when seeds were buried 5 cm deep in soil outside wire meshes without protection from seed predation by rodents. Burial in soil 5 cm deep was found effective in reducing seed predation and increasing seedling survival. Seedling recruitment was found to positively correlated with grass cover and height, while negatively correlated with shrub cover and height.