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1.
Disperser effectiveness is the contribution a disperser makes to the future reproduction of a plant. Although it is a key notion in studies of seed dispersal by animals, we know little about what determines the effectiveness of a disperser. The role of the present paper is to review the available information and construct a hierarchical framework for viewing the components of disperser effectiveness.Effectiveness has both quantitative and qualitative components. The quantity of seed dispersal depends on (A) the number of visits made to the plant by a disperser and (B) the number of seeds dispersed per visit. The quality of seed dispersal depends on (A) the quality of treatment given a seed in the mouth and in the gut and (B) the quality of seed deposition as determined by the probability that a deposited seed will survive and become an adult. In this paper I review the ways disperser behavior, morphology and physiology can influence these major components of disperser effectiveness, and when data permit present preliminary analyses of relationships among components. 相似文献
2.
The black-crested gibbon,Hylobates concolor, is one of the few species of gibbons that has not yet been the subject of a long term field study. Field observations in
the Ai Lao and Wu Liang Mountains of Yunnan Province, China indicate that in this area the habitat and ecology of this species
differ markedly from those of other gibbons that have been studied to date. These differences are correlated with some behavioral
differences. In particular, these gibbons apparently have greater day ranges than other gibbons. It has also been suggested
that this species lives in polygynous groups. To demonstrate this requires observation of groups with two or more females
with young. Our own observations and those from other recent studies suggest that there are alternative explanations consistent
with available data. 相似文献
3.
Elliott H. Haimoff X. -J. Yang S. -J. He N. Chen 《Primates; journal of primatology》1987,28(3):319-335
Black-crested gibbons (Hylobates concolor concolor), which inhabit the subtropical forests of southern China and northern Vietnam, have until now never been the subject of
any systematic behavioral or ecological field study. This report presents the findings of a three-month field study of wild
black-crested gibbons in the Wuliang and Ailao Mountain Game Reserves in Yunnan Province, People's Republic of China. The
sites visited consisted of temperate, subtropical, broadleaf evergreen forests, with trees belonging to the families Elaeocarpaceae,
Fagaceae, Lauraceae, Magnoliaceae, and Theaceae. Black-crested gibbons were documented from four sites visited and were found
to be polygynous, with an average group size of seven to eight animals. The family groups were observed to comprise one adult
male, from one to four adult females, and numerous offspring of various ages. Both sexes of this species emit interactive
songs, and various features of this loud vocal behavior were analyzed and are discussed here. Since all other gibbon species
were found to inhabit only tropical rain forests and live in strictly monogamous family groups, some of the ecological and
evolutionary implications of these findings are also presented. 相似文献
4.
从2007 年11 月到2009 年11 月,在西双版纳热带雨林中选取三棵母树,在每棵树下每年释放标记印度栲种子200 粒(三年共计1 800 粒),并追踪其命运。通过调查啮齿动物搬运和分散贮藏印度栲种子的比例,以及
查贮藏种子的微生境、贮藏点大小和扩散距离,分析贮藏种子的存活情况,进而评估啮齿动物对印度栲种子扩散的效率。结果表明,啮齿动物搬运了69.3% 的印度栲种子,被搬运的种子中18% 被分散贮藏。所有被分散贮藏的种子均被埋于落叶下或埋于土壤表层,并且大部分贮藏点仅含一粒种子。种子的扩散距离从0.5 m 到43.8 m,平均距离为7.1 m,扩散距离在年间没有显著差异。2007 年(种子密度低,啮齿动物密度高) 没有种能最终存活到实验结束,而2008 和2009 年(种子密度高,啮齿动物密度低)分别有0.3% 和1.5% 的种子存活。研究表明,啮齿动物是印度栲有效的种子扩散者,但其扩散效率很大程度上取决于森林中种子的密度和啮齿动物的丰富度。 相似文献
查贮藏种子的微生境、贮藏点大小和扩散距离,分析贮藏种子的存活情况,进而评估啮齿动物对印度栲种子扩散的效率。结果表明,啮齿动物搬运了69.3% 的印度栲种子,被搬运的种子中18% 被分散贮藏。所有被分散贮藏的种子均被埋于落叶下或埋于土壤表层,并且大部分贮藏点仅含一粒种子。种子的扩散距离从0.5 m 到43.8 m,平均距离为7.1 m,扩散距离在年间没有显著差异。2007 年(种子密度低,啮齿动物密度高) 没有种能最终存活到实验结束,而2008 和2009 年(种子密度高,啮齿动物密度低)分别有0.3% 和1.5% 的种子存活。研究表明,啮齿动物是印度栲有效的种子扩散者,但其扩散效率很大程度上取决于森林中种子的密度和啮齿动物的丰富度。 相似文献
5.
Abstract. This study focuses on the relationship between vegetation succession and soil seed bank composition on the Schiermonnikoog (The Netherlands) salt marsh over 100 yr. The importance of driftline material in seed dispersal and the relationship with succession is also investigated. The results indicate that the majority of species have a transient or short‐term seed persistent bank. Seeds of most species are able to float over the salt marsh and become concentrated in the driftline higher up the marsh. After plants have established a seed bank forms, which disappears when vegetation is replaced by later‐successional species. Exceptions are Spergularia mar‐itima, which is still present in the seed bank of late successional stages, and Juncus gerardi and Glaux maritima, which appear in the seed bank of early successional stages, but are absent in the vegetation. Based on the results of this study constraints and possibilities for salt‐marsh restoration by de‐embankment are discussed. 相似文献
6.
We examined the seed rain throughout a twelve month period in a lowlandtropical forest in Cameroon, West Africa, 1996–97. Traps (0.5m2, n = 216) were erected throughout a 25km2 area in 24 randomly placed clusters of nine trapseach. Fruits and seeds that landed in traps were collected every 7–10daysand classified by species and dispersal type. More than 32,000 seeds fromapproximately 200 species fell into the traps, an average of 297 seedsm–2 yr–1 Thirty species represent 82%of the total seed rain while an additional 175 species comprise the remaining18%. When we compared the adult community to the seed rain community within thesame plots, we found no apparent correlation between seed rain patterns andadult community structure for this year of study. Furthermore, only 49% of theadult tree community produced and dispersed seed into traps in this year. Morethan 100 species (52%) found in the seed rain represented long-distanceimmigrant seed rain. Seed rain was highly variable at several scales, bothspatially and seasonally, although seeds arrived in traps during eachcollectionperiod. Cluster analyses showed that traps within plots were seldom moresimilarto one another than traps between plots. While 82% of the tree species in thecommunity are thought to be animal dispersed, only 28% of all seeds that fellinto traps had been obviously handled (bitten, chewed, or passed)by animals. Tests for fruit and seed removal by predators or dispersers found5%or less removal rate from traps. 相似文献
7.
Animals may disperse cultivated trees outside the agricultural land, favoring the naturalization or, even, the invasiveness of domestic plants. However, the ecological and conservation implications of new or unexplored mutualisms between cultivated trees and wild animals are still far from clear. Here, we examine the possible role of an expanding and, locally, overabundant pigeon species (Columba palumbus) as an effective disperser of domestic olive trees (Olea europaea), a widespread cultivated tree, considered a naturalized and invasive species in many areas of the world. By analyzing crop and gizzard content we found that olive fruits were an important food item for pigeons in late winter and spring. A proportion of 40.3% pigeons consumed olive seeds, with an average consumption of 7.8 seeds per pigeon and day. Additionally, most seed sizes (up to 0.7 g) passed undamaged through the gut and were dispersed from cultivated olive orchards to areas covered by protected Mediterranean vegetation, recording minimal dispersal distances of 1.8–7.4 km. Greenhouse experiments showed that seeds dispersed by pigeons significantly favored the germination and establishment in comparison to non-ingested seeds. The ability of pigeons to effectively disperse domestic olive seeds may facilitate the introduction of cultivated olive trees into natural systems, including highly-protected wild olive woodlands. We recommend harvesting ornamental olive trees to reduce both pigeon overpopulation and the spread of artificially selected trees into the natural environment. 相似文献
8.
In this paper we quantify the seed pools in four locations down through a small stream in Denmark. The objectives of the study were (1) to test if the number of plant taxa in the seed pool increases downstream in the stream system; (2) to test if the seed density in the pool is highest in autumn; and (3) to analyze to what extent the seed pool contributes to re-establishment of vegetation in spring. Counting method showed no increase in species taxa in the seed pool down through the stream system. Neither did we find clear seasonal patterns in seed abundance in the seed pool. By concurrent field and laboratory observations in spring we found that seed pools can function as a source for re-establishing the vegetation in spring. However, the actual germination rate in the field was <100 and <10 times the germination rate in the laboratory for aquatic and terrestrial plants, respectively. The results suggest that small lowland streams contain large seed pools in deposition areas throughout the year, and that seed pools are much more important for the re-establishment of riparian stream vegetation in spring than submerged vegetation. 相似文献
9.
Abstract. We compare the dispersal spectra of diaspores from varied plant communities in Australia, New Zealand, and North America, assigning dispersal mode to each diaspore type on the basis of apparent morphological adaptations. Species with ballistic and external dispersal modes were uncommon in most communities we surveyed. Ant dispersal was also rather uncommon, except in some Australian sclerophyll vegetation types. The frequency of vertebrate dispersal ranged up to 60% of the flora, the highest frequencies occurring in New Zealand forests. Wind dispersal ranged as high as 70% of the flora, with the highest values in Alaska, but usually comprised 10–30% of the flora. Many species in most communities had diaspores with no special morphological device for dispersal. Physiognomically similar vegetation types indifferentbiogeographic regions usually had somewhat dissimilar dispersal spectra. The frequency of dispersal by vertebrates often increased and the frequency of species with no special dispersal device decreased along gradients of increasing vertical diversity of vegetation structure. Elevation and moisture gradients also exhibited shifts in dispersal spectra. Within Australia, vertebrate- and wind-dispersal increased in frequency along a soil-fertility gradient, and dispersal by ants and by no special device decreased. Habitat breadths (across plant communities) and microhabitat breadths (within communities) for species of each major dispersal type did not show consistent differences, in general. Ant-dispersed species often had lower cover-values than other species in several Australian vegetation types. We discuss the ecological bases of these differences in dispersal spectra in terms of the availability of dispersal agents, seed size, and other ecological constraints. Seed size is suggested to be one ecological factor that is probably of general relevance to the evolution of dispersal syndromes. 相似文献
10.
Oliver Tackenberg Christine Rmermann Ken Thompson Peter Poschlod 《Basic and Applied Ecology》2006,7(1):45-58
It is generally assumed that morphological structures like awns, bristles, or hooks increase retention potential of plant diaspores to the coats of animals, but this basic assumption has rarely been tested.In this paper we introduce a lab-experiment in which detachment rates of diaspores from mechanically shaken animal coats are measured using a standardized protocol and compared with detachment rates measured under natural conditions.The lab-experiments were used to assess ‘retention potentials’ of diaspores for more than 100 plant species. ‘Retention potential’ is defined as the proportion of diaspores still attached to the animal coat after a certain time period. We assessed the effect of several diaspore traits on retention potential and found that a strong negative effect of diaspore mass overrides the expected positive effect of structures like awns, bristles or hooks. However, a positive effect of these structures was proven, when analysing the dataset separately for diaspores of different mass classes. Additionally, we found a negative effect of flat appendages.Coat type also affects retention potentials, with higher values in curly sheep wool compared to straight cattle hair. Species with diaspore mass <2 mg had a fair chance to be dispersed in curly wool as well as in straight hair over long distances, once they get attached to the animal-coat. However, some species with diaspore mass >2 mg might also be dispersed over long distances, at least by sheep.The frequency distribution of retention potentials clearly shows that a binary classification of species dispersed in animal hair vs. species not dispersed is artificial since differences are gradual.The relative importance of diaspore mass for determining retention potential was higher in straight hair, whereas diaspore morphology had a relatively higher impact in curly wool. Hence, different sets of plant species are dispersed by different animals. 相似文献
11.
Dispersal mode,seed shadows,and colonization patterns 总被引:12,自引:0,他引:12
This review assesses the state of our knowledge about comparative seed shadows. Using data presently available in the literature, I compare the slopes (on a log-linear scale) of seed shadows for plants with different morphologically characterized modes of dispersal. The seeds of many species have no evident morphological adaptation for dispersal and seem to achieve only short-distance dispersal. Seed shadows for herbaceous species with devices for wind have flatter slopes and more distant modes and maxima than those of ballists, which in turn exceed those with no special devices. Seed shadows for wind-dispersed trees and shrubs had similar or steeper slopes than those for vertebrate-dispersed species in this sample. Species with poor mechanisms for dispersal in space only sometimes had the capacity for better dispersal in time (dormancy). Although some species exhibited seed shadows sufficiently steep to be predicted to colonize new-habitat in a front or phalanx pattern, actual colonization patterns must reflect many other factors. 相似文献
12.
对取食种子的动物而言,种子的选择、扩散以及随后的处理是一个复杂的过程。为了解济源太行山区鼠类对不同种林木种子的选择和扩散策略的差异,于2011 年9 月10 日至11 月8 日,选取山杏、桃和栓皮栎3 种林木种子,将种子标记后,释放于次生林中,以5 d 间隔,调查并记录种子命运。结果表明: (1)大林姬鼠和岩松鼠是该地区主要的种子取食者和扩散者; (2)3 种种子的扩散速率明显不同,栓皮栎种子扩散速率最快(中位存留时间8. 6 d),其次为山杏种子(中位存留时间20. 9 d),桃种子扩散速率最慢(中位存留时间37. 5 d); (3)鼠类倾向于取食栓皮栎种子(55.0%) , 埋藏山杏种子(62. 0% ),但忽略桃种子(原地存留率99. 0% );(4)88. 6%的山杏和78. 8% 的栓皮栎种子被贮藏在灌丛下方、树干基部周围和石块旁边等生境中,而仅有4 3% 的山杏和9.1% 的栓皮栎种子被贮藏于裸地中;(5)鼠类将山杏种子搬运到更远(3. 4 ± 2. 1 m,mean± SE,n =63)处贮藏;而栓皮栎种子的搬运距离则相对较近(2. 5 ± 2. 4 m,n = 57)。结果显示:鼠类对不同种植物种子具有明显的取食、贮藏偏好和不同的贮藏策略。 相似文献
13.
With light, fluorescence, transmission electron, and environmental scanning electron microscopy we studied the development of the Lunaria annua L. (Brassicaceae) seeds in order to reveal basic anatomical information about the unusual tissues of these seeds. In particular the seed tegument tissues possess complex morphological aspects that are relevant to the biology and ecology of this plant. A sclerenchymatic tissue as the innermost layer of the teguments apparently offers robust protection for the embryo, yet is organized to be flexible. This tissue likely controls the passage of water from the tegumental layers towards the embryo. We report here the presence of tannins in the pre-sclerenchymatic layer of the unripe seed. The inner tegument also houses a spongy tissue with wide intercellular spaces. This tissue could impart buoyancy to the seeds, which possibly might be required for water transport. The structural features could indicate that Lunaria may have evolved in a Mediterranean environment, which is characterized by a long dry season, but with a large amount of rainfall concentrated in short periods. Probably, not only the typical enlarged and flattened fruits of Lunaria can easily float and be dispersed away from the mother plant, but also the seeds have this dispersal peculiarity after release from the silicules. 相似文献
14.
Rex Sallabanks 《Oecologia》1992,91(2):296-304
Summary The fate of fruits from a population of European hawthorn (Crataegus monogyna) in western Oregon, USA, was examined over a two-year period. Only one frugivore, the American robin (Turdus migratorius) foraged on the C. monogyna fruits, making this an unusually straightforward fruit-frugivore system. Dispersal efficiency was low, with an average 21% of seeds being dispersed (carried away from parent plants) each year; the most common fate of fruits was to simply fall. Robins dropped 20% of the fruits that they picked, and defecated/regurgitated 40% of the fruits (seeds) that they swallowed, beneath parent plants. One trait, gruit abundance, strongly affected the probability of bush visitation by robins, bushes with larger fruit displays being preferred. Both absolute dispersal success (number of seeds) and dispersal efficiency (proportion of seeds; success per propagule) were also found to be correlated most strongly with initial fruit abundance. Individual plant fecundity and fruit quality were found to vary little between years; as a result, dispersal efficiencies for individual plants were also annully consistent. Larger (older) plants produced more fruits and therefore had higher fitness. These results suggest that the optimal fruiting strategy for C. monogyna is therefore to get as big as possible as quickly as possible by delaying fruiting until later in life. 相似文献
15.
Primary and secondary seed dispersal was investigated for the glacier lily Erythronium grandiflorum in the Colorado Rocky Mountains. These heavy seeds have no obvious adaptations for biotic or abiotic dispersal, but can be thrown short distances when the dehiscent fruits are shaken by wind. We used sticky traps to measure primary transport of seeds up to 1 m away from individual plants. A seed cafeteria experiment examined the role of ants and rodents in secondary seed transport. Primary dispersal by wind was positively skewed and median transport distances were influenced by variation in plant height. Secondary dispersal was negligible compared to Viola nuttallii, an elaiosome-bearing species. Thus, seed dispersal was highly restricted in E. grandiflorum, and a 1 m radius encompassed the modal section of the seed dispersal curve. The seed dispersal component of gene flow was quantified and combined with previous measurements of pollen flow to yield a more complete estimate of Wright's neighborhood size, N
e, for E. grandiflorum. The lack of a special seed dispersal mechanism in E. grandiflorum is discussed in terms of a source-sink model for seedling establishment with respect to distance from the parental plants. 相似文献
16.
17.
Abstract: Long-distance dispersal of seeds (LDD) surely affects most ecological and evolutionary processes related to plant species. Hence, numerous attempts to quantify LDD have been made and, especially for wind dispersal, several simulation models have been developed. However, the mechanisms promoting LDD by wind still remain ambiguous and the effects of different weather conditions on LDD, although recognized as important, have only rarely been investigated. Here we examine the influence of wind speed and updrafts on dispersal of dandelion ( Taraxacum officinale agg.), a typical wind-dispersed herb of open habitats. We used PAPPUS, a weather-sensitive mechanistic simulation model of wind dispersal, which considers frequency distribution of weather conditions during the period the simulation refers to. A simulation for the 4-month shedding period of dandelion shows that high wind speed does not promote LDD. In contrast, vertical turbulence, especially convective updrafts, are of overwhelming importance. Mainly caused by updrafts, in the simulations more than 0.05 % of dandelion seeds were dispersed beyond 100 m, a distance commonly used to define LDD. We conclude that long-distance dispersal of seeds of herbaceous species with falling velocities < 0.5 - 1.0 ms-1 is mainly caused by convective updrafts. 相似文献
18.
19.
Capuchin monkeys (Cebus spp. and Sapajus spp.) and coatis (Nasua spp.) coexist in most neotropical forests, including small forest remnants. Both capuchins and coatis eat fruit and disperse seeds, but little is known about whether their roles in seed dispersal are redundant or complementary. We compiled 49 studies from the literature on feeding by capuchins and/or coatis, of which 19 were comprehensive enough for our analyses. We determined the relative importance of fruit eating to each species and compared their diets. Additionally, we analysed the structure of three fruit–frugivore networks built with both animal groups and the fruits they eat and evaluated whether fruit traits influenced the network topology. Fruits represented the largest part of capuchin and coati diets, even though coatis have been known for their opportunistic and generalist diets. Capuchins and coatis also exhibited similar general diet parameters (niche breadth and trophic diversity). The three networks exhibited high connectance values and variable niche overlap. A Multiple Correspondence Analysis, failed to detect any trait or trait combination related to food use. In conclusion, capuchins and coatis both have generalist diets; they feed on many different species of fruits and exhibit important complementarity as seed dispersers. Both are likely to be particularly important seed dispersers in disturbed and fragmented forests. 相似文献
20.
食果动物与依赖其传播种子的植物间在进化过程中形成互惠关系,生境破碎化往往干扰种子传播过程,继而破坏这种关系.生境破碎化通常降低食果动物的多样性,但亦有相反的情况出现.食果动物对生境破碎化的适应能力不同,泛性森林动物和广食性动物具有较强的适应性.生境破碎化对依赖动物传播的植物影响有差异,多数植物受到负面影响,但也有一些植物不受影响,甚至受益.动物在破碎生境中对种子传播的有效性是种子搬运量、传播距离、种子萌发及种群建立等环节的综合效果.破碎化生境中种子的搬运量与动物的觅食行为和食物选择有关;种子传播距离受食物资源可获得性的改变和生境斑块异质性的影响;种子萌发和更新种群建立成功与否决定于是否存在有效的种子传播者.生境破碎化如何影响种子传播以及动植物相互关系,尤其是异质斑块的空间分布如何影响食果动物的传播有效性、破碎化生境下动植物互惠共生关系如何建立,生境破碎化导致的植物入侵对本地植物种子传播的影响是未来需要深入研究的问题. 相似文献