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1.
应用意大利蜜蜂和小峰熊蜂在北京平谷区果树试验站为设施桃传粉, 以研究2 种蜂的传粉行为对设施桃果实生长发育及其品质的影响。结果表明,应用小峰熊蜂授粉, 设施桃果实在整个发育过程中的果径增长速度显著高于意大利蜜蜂授粉的果实(P<0.05)。2 种蜂授粉的设施桃果实发育历期不同,小峰熊蜂授粉区的桃果实比意大利蜜蜂授粉区的果实提前7 d 左右成熟。桃的生理落果高峰在小峰熊蜂授粉区出现2 次,而在意大利蜜蜂授粉区出现3 次。在小峰熊蜂授粉区, 距离蜂箱不同距离之间的桃座果率基本一致; 而在意大利蜜蜂授粉区, 座果率随着与蜂箱距离的增大而明显降低。小峰熊蜂授粉区桃树的平均座果率略高于意大利蜜蜂授粉区, 但二者之间差异不显著(P>0.05)。经2 种蜂传粉的设施桃果实营养品质差异不显著(P>0.05), 但二者均明显优于人工授粉组(对照)。和意大利蜜蜂授粉的桃果实相比, 经小峰熊蜂传粉后的桃果实, 单果重高, 畸形果率低(P<0.05)。本研究认为中国本土小峰熊蜂为设施桃的传粉效率优于意大利蜜蜂。 相似文献
2.
The northwest of Scotland is a stronghold for two of the UK’s rarest bumblebee species, Bombus distinguendus and Bombus muscorum. The predominant form of agricultural land management in this region is crofting, a system specific to Scotland in which small agricultural units (crofts) operate rotational cropping and grazing regimes. Crofting is considered to be beneficial to a wide range of flora and fauna. However, currently there is a lack of quantitative evidence to support this view with regard to bumblebee populations. In this study we assessed the effect of land management on the abundance of foraging bumblebees and the availability of bumblebee forage plants across crofts in northwest Scotland. The results of our study show that current crofting practices do not support high densities of foraging bumblebees. Traditional crofting practice was to move livestock to uplands in the summer, but this has been largely abandoned. Summer sheep grazing of lowland pasture had a strong negative impact on bumblebee abundance and forage plant availability throughout the survey period. The use of specific ‘bird and bee’ conservation seed mixes appears to improve forage availability within the crofted landscape, although the number of bees observed remained low. Of the forage plants available, the three most frequently visited species were from the Fabaceae. We therefore conclude that the creation of agri-environment schemes which promote the use of Fabaceae-rich seed mixes and encourage the removal of sheep grazing on lowland areas throughout the summer are essential in order to conserve bumblebee populations within crofted areas. 相似文献
3.
Non-native pollinator species are now widely utilized to facilitate pollination of agricultural crops. Evaluation of the ecological risk of alien pollinators is necessary because they could have a large impact on native ecosystems through disturbing native plant-pollinator interactions. We conducted a greenhouse experiment to examine the impact of the non-native commercialized European bumblebees, Bombus terrestris, on the pollination success of seven Japanese bumblebee-pollinated plant species. Plants were exposed to three groups of bumblebees: native bumblebee(s) only (NATIVE treatment); the alien bee only (ALIEN) and a mix of the two (MIX). ALIEN treatment had negative effects on fruitset and/or fruit quality of five plants, including self-incompatible and compatible, herb and woody, and queen- and worker-pollinated species. The negative effects were caused by a decrease in legitimate flower visitation due to (1) physical inaccessibility to nectary in deep-corolla flowers by the alien bee with insufficient tongue length and, (2) biased flower preference between short-corolla flowers. Fruitset tended to decrease drastically for the self-incompatible species while fruit quality decreased moderately for the self-compatible species. Effects of MIX were not intermediate between NATIVE and ALIEN in most plant species, and caused pollination success to vary in an unpredictable manner amongst plant species, probably due to interaction between native and alien bees. This non-linear relationship between plants’ pollination success and the relative density of the alien suggests that the alien bee can disturb pollination of a plant species even when only representing a small fraction of the total pollinator community. 相似文献
4.
Exotic plant invasions threaten ecological communities world-wide. Some species are limited by a lack of suitable pollinators, but the introduction of exotic pollinators can facilitate rapid spread. In Tasmania, where many non-native plants are naturalised, exotic honeybees (Apis mellifera) and bumblebees (Bombus terrestris) have become established. We determined how these species affect the pollination of Lupinus arboreus, an invasive, nitrogen-fixing shrub, which is rarely visited by native pollinators. The proportion of flowers setting seed and the number of ovules fertilised per flower were positively related to the visitation rates of both exotic bee species. There was no effect of bee visitation rates on the proportion of seeds aborted prior to maturity, possibly due to post-fertilisation environmental constraints. We conclude that the spread of B. terrestris may not alter the fecundity of L. arboreus because of the pollination service provided by A. mellifera, and discuss potential interactions between these two bee species. 相似文献
5.
Claire Carvell 《Biological conservation》2002,103(1):33-49
Declines in the natural populations of several bumblebee species across Britain and Europe are an increasing cause for concern. In this study the habitat use of bumblebees was investigated on Salisbury Plain Training Area, the largest remaining area of unimproved chalk grassland in north-west Europe. Habitat characteristics influencing the overall abundance, species richness and foraging activity of bumblebees included the diversity and abundance of flowering plant species (particularly of favoured forage plants such as Trifolium pratense), vegetation structure and height. It is suggested that different Bombus species respond to these habitat characteristics depending on their specific foraging and nesting requirements, the case of Bombus humilis being especially relevant. The effects of several grassland management practices were considered in terms of their suitability for the conservation of bumblebee habitats. Cattle grazing was shown to be preferable to both sheep grazing and the absence of any management, although the timing and intensity of such grazing was important. Small-scale disturbances caused by vehicle activity were also of value in producing locally abundant forage resources in less intensively managed grasslands. 相似文献
6.
7.
Armando Aguirre 《Biological conservation》2008,141(2):375-384
Tropical forest fragmentation affects both biodiversity and plant reproductive success when small, isolated fragments sustain a reduced diversity or abundance of pollinators. Fragmentation-related effects have been poorly investigated in the case of palms, an important structural and functional component of tropical forests. We examined the relationships between fragment size and diversity and abundance of flower visitors, and palm reproduction, by quantifying the arthropod fauna associated to inflorescences of the palm Astrocaryum mexicanum, and its fruit set, in fragments of different size. The sample yielded a total of 228,772 arthropods (10 orders, 60 species). Coleoptera was the predominant group (?50% of the species), followed by Hymenoptera (20%), while the remaining (30%) was distributed among the other eight orders. We found a predominance of pollinating insects (Coleoptera-Nitidulidae), representing 85% of all visitors. Pollinator abundance was negatively affected by fragmentation, with a 4.2-fold average difference between small (<35 ha) and large (114-700 ha) fragments. However, fruit set was relatively high (?0.7) and not affected by fragmentation during three reproductive seasons. This could be explained because small fragments retained remarkably high numbers of pollinators (1191.4/inflorescence) and by the high abundance of palms (and flowers) in fragments. Further research is needed, however, to assess if fragmentation restricts pollinator movements to plants within the fragments, leading to a reduction in genetic variation of the progeny present in forest remnants. 相似文献
8.
The increasing spread of invasive alien plants has changed biodiversity throughout the world. To date research in this area has focused on how invasive plant species affect pollinator behaviour, but there is a lack of data on the impact that alien plant species have on wild pollinator populations. Since their introduction in the 19th century, and rapid spread after the 1950s, alien goldenrods (Solidago canadensis, Solidago gigantea) have been among the most successful invasive plant species in Europe. We studied the effects of goldenrods on wild pollinator communities in SE Poland. The abundance, species richness and diversity of wild bees, hoverflies and butterflies were compared between wet meadows invaded by goldenrod (10 transects) and non-invaded controls (10 transects). Furthermore, we compared the plant diversity and average cover between the two groups of sites. Invasion of goldenrods had a very strong negative effect on wild pollinator diversity as well as abundance. Plant diversity and average cover were also negatively affected by goldenrod invasion. Wild pollinators were grouped according to their nesting and food specialization, but none were resistant to the invasion, indicating that introduced goldenrod may affect the entire wild pollinator community. Our study emphasises the urgent need to develop specific protection plans for wild pollinators in habitats threatened by foreign plants and we call for the introduction of programs to stop the invasion of goldenrod not only in Poland, but also on a continental scale. 相似文献
9.
Studies of the interspecific relationships between alien and native pollinator species can help forecast the success of alien species as well as assess the extent of disturbance to native plant-pollinator interactions. We examined the habitat and flower resource occupancy by the invasive introduced bumble bee Bombus terrestris and three dominant native bumble bees in central Hokkaido, northern Japan, in relation to a landscape factor (forest cover ratio) and flower morphology with respect to the proboscis length of bees. Three years of monitoring the invasive boundary of B. terrestris indicated that this species, which dominates open agricultural areas, probably will not invade the forests in which the native species dominate. This habitat partitioning likely followed the displacement of the natives by the invader in open agricultural lands. In forested areas, the native species partitioned flower resources on the basis of the relationship between proboscis length and the lengths of the corolla tubes of flowers. However, in open agricultural areas, both the long- and short-tubed flowers were primarily visited by the exotic short-tongued B. terrestris, which foraged illegitimately (by nectar robbing) on long-tubed flowers (Trifolium pratense L.) and legitimately on short-tubed flowers (T. repens L. and Lavandula angustifolia Mill.). The invasion of B. terrestris into open natural vegetation, in addition to open agricultural areas, has recently been reported in Hokkaido. Even though the exotic and dominant native bumble bees partition their habitat according to landscape factors, the invasive bee has the potential to alter the overall interactions within plant-pollinator systems in the regions of open vegetation on Hokkaido Island. 相似文献
10.
Bumblebees (Bombus spp.) have undergone a documented Europe-wide decline in recent years, mostly attributable to destruction of forage and nest sites caused by agricultural intensification. This study was set up to quantify species-specific nest-site preferences of observed UK species for various types of field and forest boundary habitat. In total, 1287 observations were made of seven common bumblebee species; nest-searching behaviour was taken as being indicative of nest site preference. There was interspecific variation in preferred habitat, with some species found to be much more specific in their choice of nest site than others. A strong association was found between those species that are known to prefer subterraneous nesting and those habitats that contained banks (Bombus terrestris, B. lapidarius and B. lucorum); other species were strongly associated with tussock-type vegetation (B. pascuorum, B. hortorum and B. ruderarius). In order to safeguard the continued existence of bumblebee species it is clear that a variety of field and forest boundary types need to be conserved; this has positive implications for the conservation of other species of flora and fauna associated with agroecosystems. 相似文献
11.
The consequences of fragmentation for communities of mutualist partners are for the most part unknown; moreover, most studies addressing this issue have been conducted on plant-pollinator communities. We evaluated how the experimental fragmentation of lowland Amazonian rain forest influenced a community of ant-plant mutualists. We inventoried a total of 1057 myrmecophytes in four fragments and four continuous forest sites; the twelve plant species recorded were occupied by 33 ant morphospecies, of which 11 were obligate plant inhabitants. Neither plant species richness, ant species richness, nor total ant-plant density were significantly lower in forest fragments. However, eight of the plant species, including three of the four most common, had higher mean densities in continuous forest than fragments. Of these four species, only one (Cordia nodosa) had significantly different colonization rates between habitat types, with higher colonization rates of plants in fragments. This may be because the Azteca species it is associated with increases in abundance in forest isolates. Although our results suggest that communities of ant-plant mutualists are likely to persist in fragmented tropical landscapes 25 years after fragment isolation, most species are rare and populations sizes in fragments are extremely low. Environmental and demographic stochasticity could therefore limit long-term population viability. We suggest future studies focus on evaluating how fragmentation has altered herbivore pressure and the dispersal of ants and plants to fragments, since the interaction of these factors is likely to have the greatest impact on long-term patterns of population persistence. 相似文献
12.
Decline of leafy spurge (Euphorbia esula) in the northern Great Plains of the US is generally viewed as a success story for biological control, but quality of the vegetation that survived the infestation is key to recovery of ecosystem function. In addition, effects of other invasive species, notably cool-season exotic grasses, must be taken into account. Objectives of this study were (1) to evaluate direction and significance of changes in biomass of native and exotic grasses, forbs, and leafy spurge and in plant species composition following control of leafy spurge by flea beetles and (2) to evaluate the relative effects of leafy spurge and exotic grasses on biomass of native grasses, biomass of forbs, and richness of native species. We monitored species composition (1998-2003 and 2008) and biomass (2000, 2002, 2003 and 2008) of these groups on spurge-infested and noninfested permanent plots at three sites with unbroken prairie sod in North Dakota, USA. We found little evidence, in terms of species richness or biomass of native grasses or forbs, that leafy spurge was being replaced by desirable native species, although desirable as well as weedy and exotic species were characteristic of 2008 vegetation at all three sites. Structural equation models revealed that leafy spurge had temporally intermittent negative effects on forb biomass and species richness, but no effects on native grasses. In contrast, exotic grass had consistently strong, negative effects on native grass biomass, as well as stronger negative effects than leafy spurge on native species richness. Although substantial native plant diversity remains at these sites, exotic grasses pose an important threat to these crucial building blocks of native prairie ecosystems. 相似文献
13.
The introduction of an alien top predator, the brown treesnake (Boiga irregularis), has resulted in severe losses of native vertebrate populations in Guam. Among these are important pollinators and seed dispersers. This study is a first attempt to document cascading effects on vertebrate-pollinated native plant species in Guam. We investigated flower visitation, seed set and germination in two native plants, the mangrove tree Bruguiera gymnorrhiza and the forest tree Erythrina variegata var. orientalis. Both species are bird-pollinated. Studies were conducted on two Mariana islands, Guam (with high density of snakes) and Saipan (with nearly no snakes). Visitation rates by birds were high on Saipan, but zero on Guam. Insects and lizards visited flowers to a low extent on both islands. Only lizards were potential effective pollinators. Seed set of both species were significantly higher on Saipan compared to Guam, and for B. gymnorrhiza, seedling recruitment was significantly higher on Saipan. Hence, these bird-pollinated species appear highly dependent on bird visitors for reproduction. The eradication of flower-visiting birds by the invasive treesnake thus secondarily results in broken mutualistic interactions, which may, in turn, result in a lower recruitment of native plants. Thus, the treesnake affects not only potential prey species, but its effects cascade through the entire ecosystem on Guam. Conservation actions should be directed towards an improved recruitment (artificial pollination, planting) of the affected plant species. 相似文献
14.
Many threatened primates now exist in fragmented forest habitats. The survival of these populations may depend on their ability to utilise agricultural or other matrix habitats between forest fragments, but this is poorly known. Here, we systematically investigate an arboreal primate’s use of a heterogeneous matrix in a fragmented forest landscape: the Angola black-and-white colobus (Colobus angolensis palliatus) in southern Kenya. We used a novel technique, based on semi-structured interviews with local informants, to address the difficulty of sampling relatively rare but important events, such as dispersal between fragments. We found that colobus frequently travelled and foraged in indigenous matrix vegetation (such as mangrove, wooded shrubland and shrubland) up to 4 km from the nearest forest fragments. Agricultural habitats, such as perennial plantation (coconut, mango and cashew nut) were also used by colobus for travelling and foraging (in remnant indigenous trees). The probability of sighting colobus in the matrix increased with the proportion of both tall (>6 m) vegetation cover and food tree cover, but declined with distance from forest habitat. Our findings suggest that certain matrix habitats are important for C. a. palliatus, and that future primate conservation initiatives might benefit from adopting a ‘landscape-level’ approach to habitat management, particularly in fragmented forest systems. 相似文献
15.
Martin Allison 《Biological conservation》2004,120(2):221-228
We compared the effectiveness of topsoil removal and deep ploughing of an agriculturally improved grass field at creating suitable soil conditions for establishment of heathland vegetation. We then carried out a randomised replicated experiment involving combinations of topsoil removal, addition of heathland clippings and addition of Pteridium aquilinum litter and Pinus mulch to determine their effects on soil conditions and heathland establishment. The topsoil treatment had significantly lower concentrations of extractable P in its upper soil compared to the control plots. Both the topsoil removal and deep ploughing treatments had significantly higher pH in their upper soil compared to the control plots. Heathland vegetation established on all plots involving topsoil removal and addition of heathland clippings (with or without addition of P. aquilinum or Pinus mulch), despite soil pH in these plots being higher (5.9-6.8) than that generally recognised as being necessary for establishment of heathland vegetation. 相似文献
16.
Invasive plants with large flowering displays have been shown to compete with native plants for pollinator services, often to the detriment of native plant fitness. In this study, we compare the pollinator communities and pollen deposited on stigmas of native plant species within and away from stands of the invasive alien plant, leafy spurge (Euphorbia esula) at a large natural area in North Dakota, USA. Specifically, we ask if infestation influences (1) visitation rates and taxonomic composition of visitors to native flowers, and (2) the amount of conspecific pollen, number of pollen species, and proportion of heterospecific pollen on stigmas of native plants. We observed visits to selected native species during May and June 2000 and 2001. Stigmas were collected from a subsample of the flowers within these plots, squashed, and the pollen identified and counted under a light microscope. Visitation varied between years and among species of native plants: infestation had mixed effects in 2000 but visitation, especially by halictids was always lower within infestations in 2001. Despite differences in visitation between years, we found significantly less conspecific pollen on stigmas from infested plots in six of eight cases; we never found significantly more conspecific pollen on stigmas from within infestations. Our results emphasize the temporal variability in plant-pollinator relations and the added complexity imposed by an invasive species that will always make prediction of effects difficult. Nonetheless, the consistently lower conspecific pollen counts on native stigmas within infestations, regardless of visitation, suggest the likelihood of negative effects. 相似文献
17.
Martin Allison 《Biological conservation》2006,127(2):177-182
We investigated ways of optimising the establishment of Calluna vulgaris-dominated heathland vegetation following removal of pines from afforested heathland using a randomised block experiment. Removal of the litter layer, or both the litter and humic layers, resulted in a higher initial establishment rate of C. vulgaris compared to in the control plots. The effect of adding heathland clippings suggested that the rate of establishment of C. vulgaris was limited by seed availability in plots from which both the litter and humic layers had been removed, but not in those from which just the litter layer had been removed. Removal of both the litter and humic layers did, though, result in a long-term reduction in the depth of the humic layer, a lower loss-on-ignition and lower level of nitrate and total nitrogen compared to in the control plots. The optimal method for establishing heathland vegetation at a site will depend on: (1) whether there is a viable seedbank of C. vulgaris and other desirable heathland species present; (2) the importance of quickly establishing a high cover of desirable heathland species; (3) the likely long-term effects of soil nitrogen levels on the maintenance of C. vulgaris dominance; (4) the practicality of removing and disposing of the litter and humus layers. 相似文献
18.
Jesse M Meik Richard M JeoJoseph R Mendelson III Kate E Jenks 《Biological conservation》2002,106(1):29-36
Bush encroachment is a serious environmental and economic problem in Namibia, but little is known about impacts on native reptile diversity. Area-confined visual surveys were used to examine a diurnal lizard assemblage in central Namibian commercial ranchlands. Surveys were conducted in plots of open savanna habitat and proximal bush-encroached habitat. The following four species comprised 97.5% of all lizard observations: Pedioplanis undata, Mabuya varia, M. striata, and Lygodactylus bradfieldi. Pedioplanis undata was terrestrial, and the remaining three species were largely arboreal in our study plots. Mabuya varia was found in all savanna plots but was absent from all bush-encroached plots. Two species (P. undata and L. bradfieldi) were less abundant in bush-encroached plots. One species (M. striata) was more abundant in bush-encroached plots than in open savanna plots. Arboreal lizards demonstrated an avoidance to invasive woody plant species. Decreased diversity of habitat structure in bush-encroached habitats appears to influence native savanna lizard assemblages. Our results are consistent with accumulating evidence suggesting that bush encroachment and its associated ecological impacts are reorganizing savanna ecosystems throughout southern Africa. 相似文献
19.
Annette Kolb 《Biological conservation》2008,141(10):2540-2549
In fragmented landscapes plant species are often confined to remnants of formerly more widespread habitats, with many of their populations being small and isolated. This study experimentally examined the effects of population size and isolation on pollination, herbivory and reproductive success in the forest herb Phyteuma spicatum (Campanulaceae). In an experiment in which population size and isolation were manipulated using plants from the same origin, population size positively affected pollinator visitation, but did not alter the generally high levels of herbivory. As a result, seed production was higher in large populations. Conversely, plants originating from 14 natural populations of varying size and degree of isolation did not differ in reproductive success when grown in the same environment, suggesting similar attractiveness to pollinators and reproductive potential. The intensity of herbivory, however, was higher in progeny of small populations, at least in terms of the proportion of biomass removed. In both experiments, there were no effects of population isolation. The results suggest (1) that small population size decreases reproductive success via direct negative effects on plant-pollinator interactions, (2) that this pattern is not offset by herbivory, but (3) that herbivory enforces fragmentation effects on pollination by further reducing the number of flowering individuals and (4) that habitat fragmentation may influence plant fitness by affecting plant response to herbivory. The effects of habitat fragmentation on plant populations in present-day landscapes are thus complex, illustrating the need for more integrated studies in conservation biology that take into account both mutualistic and antagonistic plant-animal interactions. 相似文献
20.
We investigated the reproductive biology of three plants endemic to rosemary scrub habitats on the Lake Wales Ridge of Florida, USA. We used hand-pollination experiments and observations of flowers and their insect visitors to determine their mating systems and pollination. Fruit or seed set after self pollination was 94, 97, and 8% of fruit or seed set after cross pollination in Eryngium cuneifolium (Apiaceae), Hypericum cumulicola (Hypericaceae), and Liatris ohlingerae (Asteraceae) respectively, indicating that the first two are self-compatible and the last is obligately outcrossing. All three depend on insects for seed production (4-7% fruit or seed set without insects). Diverse insects visit flowers of E. cuneifolium (101 species recorded), whereas L. ohlingerae is visited predominantly by butterflies and H. cumulicola by one genus of bees (Dialictus, Halictidae). Our data indicate pollinator visitation does not currently limit seed production in E. cuneifolium or H. cumulicola, but does in L. ohlingerae. Despite the features they share (habit, habitat, disturbance regime), we found unique aspects of these species' reproductive biology yielding unique risks to population viability. We suggest that multispecies recovery plans must consider several aspects of the biology of species with superficial similarities to be successful. 相似文献