【作者】 粟海军；

【导师】 马建章；

【作者基本信息】 东北林业大学 ， 野生动植物保护与利用， 2008， 博士

【摘要】 为探索我国特有珍稀植物掌叶木(Hadeliodendron bodinievri)天然更新不良的动物性致濒因素,了解喀斯特森林生态系统中食种(实)动物对植物种子命运与种群更新策略的影响。本研究于2006年和2007年对贵州省茂兰国家级自然保护区内次生林掌叶木种群结构及更新现状、种子产量与结实特征、小型啮齿类种子捕食者及无脊椎动物种子捕食者、种子被捕食消失规律、种子初级扩散与次级扩散等内容进行了研究。研究表明种子捕食消耗是掌叶木种群衰退、更新不良的重要外因,种子命运受到种子捕食者、喀斯特小生境及种子特性三者互作影响。研究的主要结果与结论如下:1、研究地掌叶木种群自然更新不良、种群龄级结构呈现衰退表型;次生林种群中萌生结实株比例较大,蒴果出种率低;但种群结实量年间差异不明显,种子总产量相对较高,能为自然更新提供充沛种源供应。2、掌叶木种群喀斯特小生境复杂,呈多样化随机分布;种群多呈集群分布,对小生境适应性高,从实生母树和幼苗的着生生境看,石面、石沟、石缝和土面是掌叶木利用的主要小生境类型。3、研究地主要发现8种小型啮齿类动物,分别是花白竹鼠(Rhizomys pruinosus)、黄胸鼠(Rattus fravipectus)、青毛巨鼠(Beryimys bowersi)、社鼠(R..niviventer)、黄毛鼠(Rlosea)、小家鼠(Mus musculus)、针毛鼠(Niviventer fulvescens)、白腹巨鼠(Leopoldamys edwardsii),可划分为4个群落型,分别为:农田型—黄胸鼠小家鼠群落、灌丛型—针毛鼠社鼠群落、森林型—白腹巨鼠针毛鼠社鼠群落和灌丛型—社鼠针毛鼠白腹巨鼠群落。其中至少有青毛巨鼠、社鼠、针毛鼠和白腹巨鼠在林地取食掌叶木种实,又以白腹巨鼠和社鼠数量居多;啮齿动物对掌叶木种子捕食作用强烈,但年间种群数量动态并未受到掌叶木种子产量影响,说明掌叶木种子是鼠类捕食的偏好食物,但非决定性的大宗食物。4、松鼠科动物和昆虫幼虫是掌叶木树冠层的主要捕食者;松鼠科动物主要有赤腹松鼠(Callosciurus flavimanus)、隐纹花松鼠(Tamiops swinhoei)和红颊长吻松鼠(Dremomysrufigenis);对赤腹松鼠的取食观察与统计表明,在落果期间,松鼠大量剥食蒴果捕食掌叶木种子,日平均取食时长达到1.6小时,取食量达到179.1粒/h,且对种子质量有较强的选择性。树冠上的蛀果昆虫幼虫主要有桃蛀螟、卷叶螟、果蝇和蓟马,虫害率在结实初期和中期较高,平均可达13.9%和9.5%。5、蚂蚁是地面主要的昆虫类取食者,种类至少有鼎突多刺蚁(Polyrhachis Vicina)、大齿猛蚁(Odontomachus Haematodus)和东方行军蚁(Dorlus orientalis)3种,主要取食掌叶木种子的白色种衣脂肪体,但也有消耗种子和啃噬蒴果的行为。蚂蚁有强烈的搬运和就近埋藏行为,常将种子浅埋于母树下的土面小生境中,但由于搬运距离短,易受到母树阴蔽和土壤微生物、土壤动物的侵害,并未对林下更新具有明显作用。6、掌叶木的种子雨时间集中发生在每年8月下旬至9月上中旬间,年间的种子雨时间并不完全一致,种子雨强度主要受到降雨的影响。种子雨中的饱满种子比例与种子雨强度成正比,研究年度间差异性显著(Z=-2.204,P=0.028),说明种子产量的增加,有助于树冠层种子逃脱松鼠和昆虫的捕食,增加进入地表种子库的机会。7、地面种子库的种子消失动态受到种子雨强度变化的影响,种子雨强度的增大会导致地面捕食作用的增强,年间的种子雨强度变化造成地面种子消失率呈现显著差异(F=4.265,df=27,P=0.049),表明地面食种动物取食种子的不饱和性,地表种子库存在数量庞大的捕食者群体。8、进入地面种子库的种子消失呈现规律性,种子在降落后的24小时内存在最大的捕食风险(丢失率67%),48小时内93%的种子消失,而48小时到72小时的种子消失率仅为7%;表明地面动物对掌叶木种子的捕食作用强烈,而种子进入地表种子库的时间越长,逃脱捕食的可能性越大。9、喀斯特小生境类型对种子的消失率存在显著影响(χ~2=12.647,df=5,P=0.027),6种小生境的种子消失率排序依次为:石沟＞石槽＞土面＞石面＞石缝＞石洞;动物对小生境的选择性可能与捕食过程中的生境的隐蔽性、通过性等因素有关。10、运用线标法跟踪种子命运显示,大部分种子在扩散后被取食消耗掉,小部分被搬运或散落到石面、石沟和石缝生境中;被保定的种子仅在石面与石缝中有萌发,说明在条件适宜时被扩散至这三类小生境中的种子更有可能萌发和建成;这与对掌叶木现存种群的生境利用情况相符,表明了尽管食种动物是掌叶木种子巨大的消费者,但掌叶木依然需要依赖动物的捕食来传播种子,而种子是否能够萌发与建成,则取决于小生境的生存环境状况。研究表明,由于食种动物强烈的种子捕食作用,使掌叶木种子造成巨大损耗,可供更新的种子资源减少;另外,受到小生境条件和自身萌发特性的影响,被扩散的种子也极难萌发,因而造成掌叶木种群自然更新不良。基于种子捕食与种子扩散特点,可以认为食种动物与掌叶木种群间存在非平衡性进化依赖关系,而这种关系是造成其自然更新效率低下的重要因素。最后,针对这一珍稀物种的增殖与保护,还提出了相应的保育管理建议。更多还原

【Abstract】 A study on the endangerous plant Hadeliodendron bodinievri including population structure, natural regeneration,seed yields and beating characteristics,seeds predators,pattern of seeds disappearance and seeds dispersals was conducted in Maolan Natural Reserve in Guizhou Province of China in 2006 and 2007.The goals of this study were to explore the influences of seeds predation on natural regeneration of Hadeliodendron bodinievri and analyze the interaction relationship between granivorous animals and seed fates of plants in Karst forest eco-system,and the strategy of plant population’s regeneration was considered as well.Based on the results,we concluded that the seeds predation by granivorous animals is a key factor affecting natural regeneration and population recession of Hadeliodendron bodinievri,additionally the seeds fate is determined by the interaction mechanism between seeds predators,Karst micro-habitat and seeds characteristics.Main results and conclusions were listed below:1.The population demograghy of Hadeliodendron bodinievri in study area showed the natural regeneration was poor and age structure had a declining pattern.The clone parental plants taken a large proportions on the populations of Hadeliodendron bodinievri in secondary stands and the seeds output per capsule was low;but the phenomenon of masting was not distinct,and according to the effects of natural regeneration,seeds yield was high relatively which can provide a abundant supply of seeds resource.2.The types of Karst microhabitats of Hadeliodendron bodinievri were complicated with the random distribution pattern,and the pattern of population distributions of Hadeliodendron bodinievri mostly was clustered performing a highly adaption to the Karst microhabitats.Through surveying the parental plants and seedlings,it indicated that the main Karst microhabitats Hadeliodendron bodinievri used included rocky-surface,rocky-ditch,rocky-crack and soil-surface.3.8 species of small rodents including Rhizomys pruinosus,Rattus flavipectus,Beryimys bowersi,R.niviventer,R.losea,Mus musculus,Niviventer fulvescens and Leopoldamys edwardsii were found in study area,which all can be divided into four community types as below:Cropland---Rattus flavipectus & Rattus flavipectus,Shrub--- Niviventer fulvescens& R..niviventer,Forest---Leopoldamys edwardsii & Niviventer fulvescens& R..niviventer,and Shrub-- R..niviventer& Niviventer fulvescens& Leopoldamys edwardsii.Within them,Beryimys bowersi,R.niviventer, Niviventer fulvescens and Leopoldamys edwardsii were the key seed predators of Hadeliodendron bodinievri,and R..niviventer and Leopoldamys edwardsii both were dominant species in stands of study area.The quantity dynamic of population didn’t vary with the seeds yields which could indicate that the seed of Hadeliodendron bodinievri just only was the favorite food not the main critical food to the rodents. 4.The squirrels(Sciuridae) and larvas of insects both were the important seed predators in canopy of Hadeliodendron bodinievri,and the species of squirrels included CalIosciurus flavimanus,Tamiops swinhoei and Dremomys rufigenis.Squirrels had the evolutional behaviors of seeds predation that the foraging time could reach to 1.6 h and 179.1 grains per hour with a high selective ability to the seeds and capsules.The insect predators included Dichocricis punctiferalis, Adoxophyes orana,Drosophila sp.and species of Thripidae,the insected rate could reach to 13.9% and 9.5%in early periods and mid periods of fruit falling respectively.5.Ants at least including Polyrhachis Vicina,Odontomachus Haematodus and Dorlus orientalis in study area were the important seed predators to Hadeliodendron bodinievri,generally they ate the elaiosomes of seeds,but still consumed the seeds sometimes.Ants often carried or buried the seeds into shallow soil near the parental plants,but the seeds contributed less to the natural regeneration because of the damage of microbe or animals in the soil and seedling suffered from shadow beneath the parental plant.6.The seed rain of Hadeliodendron bodinievri occurred from last third part of Autumn to first ten-day period and middle ten days of September,and not always consistent annually.The intensity of seed rain was affected by precipitation significantly.The radio of sounds seeds in seed rain was proportional to intensity of seed rain in which there was a significant difference between two study years(Z=-2.204,P=0.028).This results indicated that seeds maybe had more chance to escape from the predator in canopy to enter the seed bank of ground when the seed yield increased.7.The disappearance dynamic of seed bank in ground also affected by the intensity of seed rain, which that the seed predation on ground seed bank intensified as the intensity of seed rain increased. There was a significant difference(F=4.265,df=27,p=0.049) on seeds disappearance rates between two years influenced by intensity of seed rain.So,this results showed that there was a large group of predators which consumed seeds violently to Hadeliodendron bodinievri.8.The experiments of seeds disappearance in seed bank of ground indicated that,seeds had the highest predation risk within 24h from enter the ground(disappearance rate reached to 67%),93% seeds preyed by animals within 48h and only 7%from 48h to 72h.So,it indicated that the seed predation on seed bank of ground was very strong and the seeds would have more chance to survive from predation by animals if the seeds entered the ground as long as possible.9.The types of Karst microhabitats affected the seed predation deeply(χ~2= 12.647,df=5,P =0.027 ),the seed disappearance rate in different Karst microhabitat can be rank as follow:rocky-ditch＞rocky-slot＞soil-surface＞rocky-surface＞rocky-crack＞rocky-cave.The selectivity of microhabitat in the process of seed predation by animals was relevant to cover and access of microhabitats.10.The label-tagged method was used in our study to track the seed dispersal in Karst forest area.The results showed that most of seeds were consumed by post-dispersal predation by granivorous animals,only a few of seeds moved or scattered into the microhabitats of rocky-surface, rocky-ditch and rocky-crack.Through protecting the dispersed seeds and re-visited in next year,we found the seeds moved into this three microhabitats had more chance to germination and seedling if the suitable conditions existed for seeds in the microhabitat.And,these results were accordant with our investigation to microhabitat use of population of Hadeliodendron bodinievri.So,it can be concluded that HadeIiodendron bodinievri must depend on the seeds predators to disperse the seeds at the expensive cost of seeds consumption,and when the seeds moved to somewhere by ganivorous animals,the growth condition of microhabitat would be the first determinant factors to whether the seeds can germinate or recruit into seedling.Finally,through the study,we drew a conclusion that the unsuccessful natural regeneration of Hadeliodendron bodinievri was caused by three factors:enormous seeds lose consumed by seeds predators,complicated Karst microhabitat and physiological characteristics of seed germination. Based on the traits of seed predation and seed dispersal,we believed there was a non-balance dependant evolutionary relationship between Hadeliodendron bodinievri and granivorous animals, and this relationship was a main factor to strategy failure of natural regeneration of Hadeliodendron bodinievri.Furthermore,some management suggestions were mentioned for the conservation of Hadeliodendron bodinievri in our study.更多还原