帽儿山地区秋季食果实鸟类的食性与迁徙

野外研究于2002和2003年秋季在帽儿山地区进行。帽儿山地区秋季可供鸟类取食的肉质果植物种类繁多,黄檗(Phellodendronamurense)和山荆子(Malusbaccata)是最主要的两种植物。帽儿山地区迁徙性食果实鸟类共9种,包括夏候鸟和旅鸟5种,冬候鸟4种。主要的食果实鸟类是斑鸫(Turdusnaumanni)、灰背鸫(T.hortulorum)和北朱雀(Carpodacusroseus),前两种为食果肉鸟类,后一种是食种子鸟类。斑鸫主要取食黄檗果实,灰背鸫主要取食山荆子果实,北朱雀主要取食黄檗种子。食果实鸟类在秋季也捕食一些动物性食物。3种主要食果实鸟类的迁徙日期不同。灰背鸫最先迁离,斑鸫稍晚,北朱雀最后到此越冬。果实丰歉年对鸟类的迁徙有一定的影响。     

食果鸟类对红楠种子的传播作用

肉质果植物通常依赖食果鸟类等取食果实后经消化道过程传播种子, 以完成种群的更新。红楠(Machilus thunbergii)是亚热带森林的代表性种类, 其果实具有依赖鸟类等动物取食后传播的特点。2012 年、2013 年在梅花山国家级自然保护区,研究了鸟类对红楠果实的取食及种子的传播作用。结果如下: 取食红楠种实的鸟类共计18 种, 其中整吞果实的鸟类12 种,啄取果肉的鸟类5 种, 啄食种子的鸟类1 种。整吞果实鸟类中4 种鹎科和2 种鸦科鸟类访问频次和取食量较大, 是主要的种子传播者。鸟类主要以呕吐方式传播种子。取食后初停栖点与母树距离及地面种子散布地点的分析结果表明, 鸟类可以远距离扩散种子。地面种实可被啮齿动物或蚁类再次捕食或搬运。研究表明, 红楠可以借助鸟类实现种子传播和种群更新。     

食果鸟类在红豆杉天然种群形成中的作用

2005年10月初至2006年2月,在南京中山植物园研究了红豆杉(Taxus chinensis)天然更新种群的分布格局,野外定点观察了鸟类对红豆杉种子的取食行为,记录了红豆杉落果的命运,分析了食果鸟类在红豆杉种群形成中的作用。结果表明:红豆杉天然更新种群集中分布于距母树群10m以外面积约0.5hm2的山坡上,全部红豆杉幼苗、幼树共213株,主要分布在中下坡;幼苗和幼树的空间水平格局符合聚集分布特征。"果实"成熟后,一部分被鸟类直接在树上取食,一部分掉落母树下地面。经过对结实母树的定点、连续观察,记录到4种鸟类取食红豆杉"果实",其中红嘴蓝鹊(Urocissa erythrorhyncha)和白头鹎(Pyc-nonotus sinensis)为主要的取食者和传播者。食果鸟类整吞"果实",消化果肉(假种皮)后,种子经消化道随粪便排出,以此过程传播种子。在取食完红豆杉"果实"后,食果鸟类多飞向坡上。坡上排水良好,有适量的荫蔽,生境适宜红豆杉种子萌发和幼苗的成长。因此,食果鸟类将种子传播至适宜萌发和生长的环境中,对该红豆杉种群的天然更新起主要作用。同时,鸟类传播对于红豆杉种群扩散、占据新的生境也有着特殊的意义。     

鸟类取食中国沙棘果实的方式及其对种子的传播作用

2003年9月～2004年3月,定期观察取食中国沙棘果实的鸟类及其取食方式。共记录取食中国沙棘果实的鸟类18种,其取食果实的方式主要有：1)直接在树冠上吞食果实,有时候在吞食后将种子呕出;2)将果实从树上衔走后,在栖息处吞食或啄食;3)将果实啄落至地面,然后取食果肉和种子,留下果皮;4)啄破果皮,吸食果肉,留下果皮及种子;5)从顶端将果皮啄破后,仅取食里面的种子。不同的取食方式决定了它们对沙棘种子的传播作用不同。收集鸟粪便中的种子与完整的干果实及人工剥离果肉和内果皮的种子做萌发对比实验,结果表明,鸟类消化道过程对种子的萌发有一定影响,但萌发率仍较高。沙棘为多种鸟类提供食物,而鸟类则为沙棘传播种子,它们之间形成一种互利关系。     

脊椎动物传播植物肉质果中的次生物质及其生态作用

在种子植物-动物的互惠关系中,植物果实成熟后需要吸引种子传播者取食果实,传播其种子至适宜萌发的生境,同时又要防御种子捕食者过度消耗种子。果实内的次生物质(如:配糖生物碱、大黄素、辣椒素)在此过程中起到重要的调控作用。依赖脊椎动物传播的肉质果中往往含有与植物茎、叶内相同的次生物质,其种类繁多,主要分为含氮化合物、酚类化合物和萜类化合物。未成熟果实内富含次生物质(如:单宁、大黄素),主要保护未成熟种子不被潜在的捕食者和食果动物取食,这些次生物质的含量通常随果实成熟而降低;其它次生物质(如:脱辅基类胡萝卜素)的含量随果实成熟而增多,可能起到吸引食果动物的作用。在对脊椎动物捕食的抵御中,果实内不同类型的次生物质促使成熟果实对所有脊椎动物都有毒性(专毒性)或者仅对种子捕食者有毒性(泛毒性)。肉质果内的次生物质对植物-食果动物相互关系的调控作用,还可以通过调节动物取食频次和数量、抑制和促进种子萌发、改变种子在肠道的滞留时间、吸引传播者等生态作用而实现。某种次生物质往往集多种生态作用于一身。目前对肉质果内次生物质与脊椎动物相互关系的探讨还不够深入。未来研究需要综合考虑植物次生物质与果实生理生化、形态学等特征对食果者的综合调控机理;次生物质在种子传播后的调控作用对植物种群或群落结构和分布格局的影响;从动植物协同进化角度探讨植物次生物质的产生、防御和吸引策略与脊椎动物对果实的选择和消费之间的关系等。开展脊椎动物传播肉质果实中次生物质的研究,对完善种子传播机制、植物繁殖和更新格局,丰富动植物相互作用、协同进化理论具有重要的意义。     

南方红豆杉的天然更新格局及食果鸟类对其种子的传播

2006年9-12月,在皖南仙寓山对南方红豆杉(Taxus chinensis var.mairei)天然更新种群的分布格局及食果鸟类对其种子的传播作用进行了研究.结果表明:天然更新种群集中分布于仙寓山海拔540 m以上面积约1.1 hm2的山坡上,与毛竹混生.共统计红豆杉1 331株,其中高度30 cm以下的幼苗1 167株,占总数的87.68%.该红豆杉种群为缓慢增长型种群,空间水平格局呈聚集分布.经过对结实母树的定点连续观察,记录到10种鸟类取食红豆杉种子,其中红嘴蓝鹊(Urocissa erythrorhyncha)、栗背短脚鹎(Hemixos castanonotus)和绿翅短脚鹎(Hypsipetes mcclellandii)为主要的取食者和传播者.食果鸟类吞入种子后,消化果肉(假种皮)后,种子随粪便排出而得以传播.野外调查中,在鸟类经常活动的地点发现带有红豆杉种子新鲜的鸟类粪便,每个含有1～2颗种子.未被鸟类取食的落果自然掉落于树冠下,假种皮被昆虫取食或腐烂,种子在母树下能正常萌发,但存活率几乎为零.因此,鸟类在该红豆杉天然种群形成中起到了重要作用,它们将种子传播至适宜萌发和生长的环境中.     

五蕊寄生种子萌发特性

采用室内与野外实验相结合的方法,对五蕊寄生（Dendrophthoe pentandra）种子萌发特性以及鸟类消化过程对其种子萌发的影响进行研究。结果表明：五蕊寄生种子对温度和光照较敏感,与黑暗条件相比,光照能显著提高种子的萌发率;20℃为种子萌发的最适温度,萌发率达53.8%,高温35℃及低温10℃均不利于种子萌发。研究发现纯色啄花鸟（Dicaeum concolor）是该植物的主要食果者,种子外的果肉不是限制种子萌发的关键因素,人为去除果肉并不能提高种子的萌发率,但可缩短种子萌发的时间,果实通过纯色啄花鸟类肠道消化后,随着粪便排出的种子萌发率显著提高（达69%）,暗示纯色啄花鸟在五蕊寄生的种子萌发过程中具有重要的作用。     

动物对花楸树种实的取食与传播

花楸树是我国东北林区重要的非木质资源树种,其种实既有自然散布方式,也有动物散布方式.本文通过对花楸树种实散布过程中动物活动特点的研究,探索动物取食和传播花楸树种实的规律及其对花楸树天然更新的影响.在2008和2009年花楸树果实成熟期,通过定期观察取食花楸树果实的鸟类及其取食方式,确定对花楸树果实有拜访行为的鸟类有8种,其中食果肉鸟类斑鸫、灰喜鹊和白背啄木鸟对花楸树种实有传播作用,它们对花楸树果实的拜访频率分别为54%、12%和7%,取食后第一落点集中于距离母树5～10 m之间（占68.2%）,其次为距离母树5 m以内（占27.3%）,距离母树10 m以外的比例很小（占4.5%）.果实在鸟类消化道内的滞留时间可达20 min,表明潜在传播距离会很长.人工摆放果实和种子试验表明,在不同生境地面摆放的果实6～7 d内全部消失,果实的取食者主要是啮齿类和地面取食的鸟类,取食率均较高（50%～70%）;种子的取食者为啮齿类、地面取食的鸟类和蚁类,取食率均较低（1%～5%）.花楸树为多种动物提供食物,而动物为花楸树传播种子,动物的取食对花楸树的天然更新有重要影响.     

都江堰林区取食樱桃果实(种子)的鸟类及其种子扩散作用

樱桃(Prunus pseudocerasus)是广泛分布于我国亚热带常绿阔叶林内的一种重要核果植物。为了解食果鸟类在樱桃种群更新中的作用,于2007年和2008年在四川都江堰亚热带常绿阔叶林内研究了取食樱桃果实(种子)的鸟类及其种子扩散作用。研究表明,樱桃成熟果实的下落高峰发生在4月下旬至5月上旬;2007年的种子扩散率为4.0%±1.0%,明显低于2008年(27.7%±5.7%)。在研究地内,发现至少有16种鸟取食樱桃果实或种子,根据其对果实和种子的处理方式分为3个功能群:白头鹎(Pycnontus sinensis)、领雀嘴鹎(Spizixos semitorques)、黑鹎(Hypisipetes leucocephalus)、白颊噪鹛(Garrulax snnio)、红嘴蓝鹊(Urocissa erythorhyncha)等10种鸟吞食樱桃果实,而种子通过消化道末端排出并将种子携至远离母树的地方,是重要的种子扩散者;暗绿绣眼鸟(Alcippe morrisonia)和灰眶雀鹛(Zosterops iaponicus)等4种鸟主要啄食果肉而将种子丢弃在母树下,为啄食果肉者;而普通朱雀(Carpopacus erythrinus)和灰头鸦雀(Paradoxornis gularis)则主要取食种子,为纯粹的种子捕食者。在吞食樱桃果实的食果鸟中,3种鹎科鸟类访问频次所占的比例达55.3%(2007年)和35.3%(2008年),说明鹎科鸟类是都江堰林区樱桃种子的主要扩散者,对樱桃种群的空间格局和自然更新可能有重要影响。     

Physiological dormancy broken by endozoochory: Austral parakeets (Enicognathus ferrugineus) as legitimate dispersers of calafate (Berberis microphylla) in the Patagonian Andes

种子由动物内携传播是植物再生和新种群建立的重要过程。具有休眠的种子经过传播者肠道传代作用后可能特别受益。然而，肠道 传代作用如何影响具有生理休眠植物的萌发尚不清楚。在本研究中，我们实验性地评估了南鹦哥(Enicognathus ferrugineus)作为小檗属植 物(Berberis microphylla)传播者的互惠共生。Berberis microphylla是一种多刺的灌木，栖息在南美洲温带森林的下层，其种子具有深度生 理休眠的特性。本研究通过四种处理：(1)种子消化处理，(2)粪便提取物消化处理，(3)果实种子完整处理和(4)包含果肉果实种子完整 处理，测定了从粪便和完整果实中提取的B. microphylla种子的发芽成功率和活力。研究结果表明，大约65%的南鹦哥的粪便中含有B. microphylla种子。不同处理的种子存活率无显著差异。然而，消化后的种子萌发率显著高于完整果实种子，而粪便和果肉提取物处理之间没有差异。粪便和果肉都没有为种子提供任何提高发芽能力的生态优势，但在萌发时间上确实造成了一些劣势。由于持续降雨和巴塔哥尼亚安第斯山脉春季融雪带来的严重冲刷，种子附近的粪便在雪下几个月后就会完全缺失。消化种子较高的发芽能力和较快的发芽速度验证了南鹦哥和B. microphylla之间具有合理互惠共生的假设。因为消化和非消化种子发芽能力的差异，我们假设通过传播者的肠道传代作用可能打破种子的生理休眠。我们的研究结果强调了在具有高度季节性的环境下，具有生理休眠的植物物种中与动物内携传播的相关作用。     

Fruits foraging patterns and seed dispersal effect of frugivorous birds on Hippophae rhamnoides sinensis

Behaviors of 18 species of birds eating fruits of Hippophae rhamnoides spp.sinensis were observed from September 2003 to March 2004.Their foraging patterns were found to be very different and Can be divided into five classes:(1)direct swallowing the fruits on crown of the shrubs and sometimes regurgitating seeds soon after;(2)carrying the fruits to their perching sites and swallowing;(3)pecking the fruits from the shrubs to the ground,eating pulp and seeds but leaving pericarp;(4)pecking through the pericarp,eating pulp and leaving pericarp and seeds;(5)pecking through the pericarp on the top of fruits,and only eating seeds.These foraging patterns have different effects on seed dispersal of H.rhamnoides spp.sinensis.The germination experiment of three groups of seeds(seeds from feces,dry fruits and extracted seeds from dry fruits)was carried out.Although ingestion processes of birds had some adverse effects on the seed germination of H.rhamnoides spp.sinensis,the seeds from feces still have a relatively higher germination ratio.H.rhamnoides spp.sinensis provides food to a variety of frugivorous birds.and the birds disperse its seeds.Thus,a mutually beneficial relationship between the bird and the seed is formed.     

The role of frugivorous birds in fruit removal and seed germination of the invasive alien Cotoneaster franchetii in central Argentina

Many invasive plant species have fleshy fruits that are eaten by native frugivorous birds which disperse their seeds and may facilitate their germination, playing an important role in plant invasion success. The fleshy‐fruited shrub Cotoneaster franchetii (Rosaceae) is an important invasive alien in the mountainous regions of central Argentina. To determine the role of avian frugivorous in fruit removal of this species, we conducted a frugivore exclusion experiment including bagged and unbagged branches in 75 plants of C. franchetii. At the end of the dispersal period, we compared the percentage of missing fruits (removed by birds + naturally dropped) in unbagged branches with the percentage of naturally dropped fruits in bagged branches. To assess whether any mechanism acting on seeds during their passage through bird guts (de‐inhibition by pulp removal and/or seed scarification) affects seed germination of this species, we compared percentage and speed of germination among seeds obtained from faeces of the native frugivorous Turdus chiguanco, from manually de‐pulped fruits, and from intact fruits. The percentage of missing fruits per shrub in unbagged branches was significantly higher than the percentage of naturally dropped fruits in bagged branches, suggesting that frugivorous birds play an important role in fruit removal of C. franchetii in the study area. Seeds from bird faeces and from manually de‐pulped fruits germinated in higher percentage and faster than seeds from intact fruits. Germination percentage and speed of seeds from manually de‐pulped fruits were significantly higher than those of gut‐passed seeds. These results indicate that T. chiguanco increases and accelerates seed germination of C. franchetii through pulp removal, but not through seed scarification. Overall, our findings indicate that native frugivorous birds facilitate the dispersal and germination success of C. franchetii, likely playing an important role in its invasion throughout the mountainous region of central Argentina.     

Non-redundancy in seed dispersal and germination by native and introduced frugivorous birds: implications of invasive bird impact on native plant communities

Seed dispersal by vertebrate animals is important for the establishment of many fleshy-fruited plant species. Different frugivorous species can provide different seed dispersal services according to their specific dietary preferences as well as behaviour and body traits (e.g. body size and beak size of birds). Our aim was to study redundancies and complementarities in seed dispersal and germination between the two main native seed disperser birds and the introduced silver pheasant Lophura nycthemera in the temperate Patagonian forests. For this, we collected fresh droppings from the studied species and analyzed seed content. We conducted germination trials for four plant species common in bird droppings; two native species (Aristotelia chilensis and Rhaphithamnus spinosus) and two invasive non-native species (Rubus ulmifolius and Rosa rubiginosa). Both native frugivorous birds and the silver pheasant dispersed fruits of non- native fleshy-fruited plants, but their roles were non-redundant in terms of species dispersed and effect on seed germination. The silver pheasant dispersed a proportionally high number of non-native seeds, while native birds dispersed a high number of native seeds. In addition, the effect of gut treatment in seed germination differed between seed dispersers. Native birds promoted the germination for the two native plant species studied, while the silver pheasant promoted the germination of one non-native plant. This suggests that seed dispersal by the silver pheasant may contribute to the spread of some invasive fleshy-fruited plants in the ecosystems that otherwise would not be dispersed by any other bird. The understanding of redundancies and complementarities on seed dispersal and germination between native and introduced birds will allow improving the management of fleshy-fruited non-native plants.     

The Role of Arboreal Seed Dispersal Groups on the Seed Rain of a Lowland Tropical Forest1

Most tropical plants produce fleshy fruits that are dispersed primarily by vertebrate frugivores. Behavioral disparities among vertebrate seed dispersers could influence patterns of seed distribution and thus forest structure. This study investigated the relative importance of arboreal seed dispersers and seed predators on the initial stage of forest organization–seed deposition. We asked the following questions: (1) To what degree do arboreal seed dispersers influence the species richness and abundance of the seed rain? and (2) Based on the plant species and strata of the forest for which they provide dispersal services, do arboreal seed dispersers represent similar or distinct functional groups? To answer these questions, seed rain was sampled for 12 months in the Dja Reserve, Cameroon. Seed traps representing five percent of the crown area were erected below the canopies of 90 trees belonging to nine focal tree species: 3 dispersed by monkeys, 3 dispersed by large frugivorous birds, and 3 wind‐dispersed species. Seeds disseminated by arboreal seed dispersers accounted for ca 12 percent of the seeds and 68 percent of the seed species identified in seed traps. Monkeys dispersed more than twice the number of seed species than large frugivorous birds, but birds dispersed more individual seeds. We identified two distinct functional dispersal groups, one composed of large frugivorous birds and one composed of monkeys, drop dispersers, and seed predators. These groups dispersed plants found in different canopy strata and exhibited low overlap in the seed species they disseminated. We conclude it is unlikely that seed dispersal services provided by monkeys could be compensated for by frugivorous birds in the event of their extirpation from Afrotropical forests.     

Potential role of frugivorous birds (Passeriformes) on seed dispersal of six plant species in a restinga habitat, southeastern Brazil

Restingas are considered stressful habitats associated with the Brazilian Atlantic forest, and their ecological interactions are poorly known. The goal of the present study was to determine the potential role of frugivorous birds as seed dispersers in a restinga habitat. Data were collected in Parque Nacional da Restinga de Jurubatiba, southeastern Brazil, where the main physiognomy (Open Clusia Formation) is characterized by the presence of patches of vegetation covering 20 to 48 % of the sandy soil and reaching a height of 5 m. Birds were captured with mist nets (12 x 2.5 m; 36 mm mesh; 1,680 net-hrs) and had their fecal and regurgitate samples inspected for seeds. Six plant species found in these bird samples were studied. The germination of seeds obtained from plants was compared to those from the birds. Both groups of seeds were set on Petri dishes at room temperature and washed when infected with fungi. In general, there was no effect on germination rate, and the effect on germination speed was negative. Germination of seeds from Pilosocereus arrabidae treated by the birds seemed to be influenced by storage of defecated seeds, while few Miconia cinnamomifolia seeds both from plants and from birds germinated. Ocotea notata presented a great variation in time to the onset of germination, perhaps an advantage against dissecation. Aechmea nudicaulis, Clusia hilariana and Erythroxylum subsessile probably take advantage of the arrival to favorable microhabitats, not by the gut effect on the seeds. All plant species studied are numerically important for the community and some of them are main actors in the succession of vegetation patches. Among the birds, Mimus gilvus is an important resident species, endemic to restingas in Brazil, while Turdus amaurochalinus is a visitor and may be important for plants that fructify during its passage by the study site. Although the effect of pulp removal was only tested for one species (Achmea nudicaulis) in the present study, we confirmed that the tested effect of restinga frugivorous birds on seed germination was generally null. Although there is a need for more detailed studies on specific animal-plant interactions on this habitat, the overall effect of the birds on seed dispersal in restinga is probably positive.     

Fruit size in wild olives: implications for avian seed dispersal

1. The response of frugivorous birds to an enlargement of fruit size, and the consequences for both birds and plants, are analysed for the interaction between avian seed dispersers and olives ( Olea europaea) .
2. The enlargement of fruit size promotes a shift in frugivorous birds' feeding behaviour, from swallowing fruits whole to pecking pieces of pulp. The relative frequency of olive consumption using each feeding behaviour was assessed by combining field data on frequency of appearance of olive pulp and seeds with data from laboratory trials.
3. Sardinian Warblers ( Sylvia melanocephala ) and European Robins ( Erithacus rubecula ) were mainly peckers both on cultivated and wild olives. Blackcaps ( Sylvia atricapilla ) consumed wild olives mainly by swallowing but consumed cultivated olives (larger than the wild ones) primarily by pecking. Song Thrushes ( Turdus philomelos ) were primarily swallowers of both types of fruits.
4. Laboratory trials with Song Thrushes, Blackcaps and European Robins showed that: (a) all were able to peck fruits; (b) fruit size determined a shift from swallowing to pecking, as pecking frequency increased with the enlargement of the fruit size; (c) all the species had an increased fruit handling failure rate when trying to swallow increasingly large fruits; and (d) from the birds' perspective, small shifts in fruit size may have important consequences on fruit profitability.
5. Pecking on olives turns the mutualistic fruit–frugivore interaction into a fruit-pulp predator interaction, thus arising a conflict between the plant and frugivorous birds.
6. This study shows that heavy dependence on fruit is not always simply related to seed dispersal. The same frugivorous bird species can act as a seed disperser or a pulp predator for the same plant species. The threshold between these roles is highly influenced by the ratio gape size/fruit size.     

Are predatory birds effective secondary seed dispersers?

We have studied the unusual phenomenon of secondary seed dispersal of Lycium intricatum seeds on a small oceanic Atlantic island (Alegranza, Canarian Archipelago) in which a small frugivorous lizard ( Gallotia atlantica ) and two different predatory birds participate, a shrike ( Lanius excubitor ) and a kestrel ( Falco tinnunculus ). Endemic lizards that are common prey of both bird species consume Lycium fruits. Lizard remains were significantly matched with the presence of Lycium fruits in the regurgitation pellets of the two predatory birds. Seeds were found in 7.3% of the lizard droppings, 31.0% of kestrel pellets and 55.7% of shrike regurgitations. The mean number of seeds per dropping or pellet was 4.8 ±4 in lizard, 20.2 ±34.5 in shrike and 6.7 ±8.1 in kestrel. The percentage of viable seeds showed significant differences among all four treatments, decreasing in the following direction: seeds collected directly from plants (98.0%), shrikes (88.0%), lizards (72.3%), and kestrels (31.7%). Seeds from Lycium fresh fruits and shrike pellets showed significantly higher germination rates than those from lizard droppings and kestrel pellets. While lizards and shrikes are effective seed dispersers, kestrel gut treatment decreases seed viability. Seed viability is always higher than seed germination in each of the four treatments. In this island environment, Lycium seeds are under an important random influence during the seed dispersal process. Secondary seed dispersal seems to acquire a relevant dimension in small and remote insular environments or isolated continental systems where interactions among the different elements involved are intense, all of them are abundant native residents, and they have been coexisting for a long time. © 2002 The Linnean Society of London, Biological Journal of the Linnean Society , 2002, 75 , 345–352.     

Directed vertebrate-mediated seed dispersal of a fleshy-fruited amaryllid in a heterogenous habitat

Most plants with fleshy fruits have seeds that are ingested by animals, but a less well-understood mode of seed dispersal involves fleshy fruits containing seeds that are discarded by frugivorous animals because they are too large or toxic to be ingested. We studied the seed dispersal biology of Haemanthus deformis, an amaryllid lily species found in a mosaic of bush clumps in a grassland matrix in South Africa. We asked whether seed dispersal is directed in and among bush clumps and whether germination and survival are greater for seeds dispersed to bush clumps than for those dispersed into grassland. Using camera trapping, we found that fruits are consumed mainly by birds and rodents. The pulp was removed from the seeds which were then discarded without ingestion. While many seeds were dispersed close to the parent plant, most (c. 78.5%) were dispersed further than 1 m away from the parent plant. Longer distance dispersal resulted mainly from birds flying off with fruits in their bill or from rodents engaging in scatter-hoarding behavior. Seedling survival was most successful within bush clumps as compared to grasslands and shade was identified as a primary requirement for seedling survival. Seeds from which the fruit pulp had been removed germinated faster than those in intact fruits. Haemanthus deformis deploys a system of directed seed dispersal, whereby both birds and rodents contribute to the dispersal of seeds within patchy bush clumps that are favorable for seedling survival.     

Fruits foraging patterns and seed dispersal effect of frugivorous birds on Hippophae rhamnoides sinensis

Behaviors of 18 species of birds eating fruits of Hippophae rhamnoides spp. sinensis were observed from September 2003 to March 2004. Their foraging patterns were found to be very different and can be divided into five classes: (1) direct swallowing the fruits on crown of the shrubs and sometimes regurgitating seeds soon after; (2) carrying the fruits to their perching sites and swallowing; (3) pecking the fruits from the shrubs to the ground, eating pulp and seeds but leaving pericarp; (4) pecking through the pericarp, eating pulp and leaving pericarp and seeds; (5) pecking through the pericarp on the top of fruits, and only eating seeds. These foraging patterns have different effects on seed dispersal of H. rhamnoides spp. sinensis. The germination experiment of three groups of seeds (seeds from feces, dry fruits and extracted seeds from dry fruits) was carried out. Although ingestion processes of birds had some adverse effects on the seed germination of H. rhamnoides spp. sinensis, the seeds from feces still have a relatively higher germination ratio. H. rhamnoides spp. sinensis provides food to a variety of frugivorous birds, and the birds disperse its seeds. Thus, a mutually beneficial relationship between the bird and the seed is formed. __________ Translated from Chinese Journal of Ecology, 2005, 24(6): 635–638 [译自: 生态学杂志, 2005, 24(6): 635–638]