首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献，搜索用时 656 毫秒
1.
Urban green areas, due to their high plant diversity, can be supportive as floral resources (nectar and/or pollen) to wild and managed pollinating insects. This research aims towards understanding the contribution of ornamental ground cover perennials as a food source for urban pollinators. We compare floral phenology and abundance, nectar and pollen production, and insect visitation to flowers of Geranium macrorrhizum, G. platypetalum and G. sanguineum, planted in the botanical garden of Lublin, SE Poland. The investigation revealed that the studied hardy geraniums exhibit many features valuable for pollinators, including large floral display (G. macrorrhizum and G. platypetalum), extended flowering period (G. sanguineum) and ample nectar and pollen reward (G. macrorrhizum). They can supply urban pollinators with a high quality food during spring and early summer time, i.e. the period of high food demand by many bee species. Moreover, hardy geraniums might be valuable plants for urban beekeeping as they are eagerly visited by honeybees. The investigated ground cover plants could therefore be considered in future city plantings.  相似文献   

2.
Pod-setting in runner bean crops depends on the building up and maintenance of a sufficiently large population of efficient insect pollinators, and this appears to be affected by the early spring weather.

Runner bean flowers were visited and could be pollinated both by bumblebees (Bombus spp.) and honeybees (Apis mellifera). Visits to the front of the flower for nectar or pollen resulted in pollination, but “nectar-robbing” via a hole bitten through the underside of the flower, caused little or no pollination. During periods of intense nectar-robbing activity, pollination efficiency varied widely and depended largely upon whether or not insects were also collecting pollen from the crop.

A technique was devised for measuring the daily insect pollinating efficiency in a crop, that is, the actual daily pod-set as a percentage of the potential daily pod- set. A simple visual method for assessing the current day’s pollinating activity in the field is described, and the efficiency thus indicated compares well with results obtained from experimental pollination efficiency measurements.  相似文献   

3.
An apple orchard consisting of a single commercial cultivar and of pollinizers such as Crab apples under the condition of natural pollination needs pollinators for stable fruit production. We investigated the foraging behavior of pollinators, especially Osmia cornifrons Radoszkowski, in order to evaluate their use instead of honeybees.  相似文献   

4.
Mason bees have been successfully managed as orchard pollinators in Japan and USA for many decades. Recently, the European species Osmia bicornis (L.) and Osmia cornuta (Latr.) attract more interest as pollinators in fruit orchards in Germany. Several studies indicate the potential of these mason bees as pollinators of pome and stone fruit. Here, we investigated the composition of the pollen loads in the brood cells of these two mason bees in fruit orchards different in habitat characteristics. At eight study sites, trap nests and cocoons of O. bicornis and O. cornuta were installed. During fruit tree blossom, pollen was sampled every two weeks and the percentage of Rosaceae pollen was identified. Landscape characteristics were assessed in a radius of 250 m from the trap nests. At all eight study sites, O. bicornis and O. cornuta collected pollen of Rosaceae. The percentage of Rosaceae pollen in the samples and the local habitat quality of the foraging sites were negatively correlated. In fruit orchards with a low diversity of suitable foraging habitats, brood cells contained a relatively high percentage of fruit tree pollen. These results indicate the potential of O. bicornis and O. cornuta as efficient pollinators in intensively managed fruit orchards. However, intensive fruit orchards appear less suitable as habitats for these mason bees to establish an endogenous pollinator population. Hence, the introduction and management of mason bees in orchards will improve pollination.  相似文献   

5.
Pollination is a key ecological service for human food security and the reproduction of the majority of flowering plants. This plant-animal interaction is crucial in both wild and urban habitats, however, increasing urbanization and change in land use alter these interactions. The concerns regarding pollination have led to numerous efforts aimed at improving the quality of wildlife in cities, however, understanding the importance of these activities warrants further research. In Warsaw, the Polish capital, we analyzed the influence of urban-related factors such as floral resource richness, the proportion of green areas in the proximity of foraging sites, air pollution or temperature on plant-pollinator interaction in 14 meadows. We also analyzed the reproductive success and the heterospecific pollen transfer in the case of plants growing in the meadows. Our study revealed that the frequency of visits to flowers was related to city-related factors, but the reaction varied among different groups of pollinators. For example, bumblebees were negatively influenced by higher air pollution, while the rest of the flower visitors were not, Syrphidae flies were more frequent flower visitors when the proportion of green area was higher in the buffer of 150 m, while we did not observe this tendency in other groups of flower visitors. Plants growing in Warsaw meadows were frequently visited and effectively pollinated - urban pollinator assemblages seem to provide sufficient pollination services to plants growing in the city. Species-rich communities were not a threat to pollination; we found mostly conspecific pollen grains on the stigmas of the studied plant species. The results of our study show that species-rich communities make a valuable contribution to pollinator conservation. The conservation activities, however, should be adjusted to the target group of pollinators, since different groups of flower visitors respond differently to urban-related factors studied.  相似文献   

6.
Summary

In this paper, the floral biology and pollination ecology of Salvia splendens are described. All flower characteristics (red corolla, large tubular flowers with abundant but dilute nectar) indicate that S. splendens is adapted to hummingbird pollination. Honeybees, however, were also found to be good pollinators of this plant. Apis mellifera was equally effective in pollinating S. splendens as hand pollination and open pollination, resulting in a 300% increase in seed set compared with bagged control plants. The much smaller stingless bee Tetragonisca angustula was not an effective pollinator of these flowers since during visitation its body failed to touch the stigma. Although pollination seemed not to be the only limiting factor in seed production, external pollinators enhance seed production in S. splendens, and Apis mellifera is an effective, commercially available pollination agent of this economically important ornamental plant.  相似文献   

7.
Observations on native and domestic insect pollinators were carried out during the blossom period from 1978 to 1980 in a semi-dwarf apple orchard in Ontario. Weather conditions and numbers of blossoms per tree were also recorded. Apis mellifera was the most frequent pollinator for all years. The Anthomyiidae (Diptera) ranked second for 1978 and 1979, but in 1980 the Andrenidae and Halictidae were of greater importance than the Diptera. The efficiency of the pollinators was determined by analysis of the pollen carried on their bodies. Hymenoptera had more pollen on their bodies than the Diptera. Among the Hymenoptera, the Andrenidae and the pollen-gathering Large Andrenidae had the greatest amount of fruit pollen on their bodies. Among the Diptera, the Syrphidae had the greatest amount of fruit pollen. The effectiveness of the pollinators was evaluated by measuring fruit set, seed set and the effective pollination period. There was no significant difference in fruit set between years inspite of adverse weather in 1979. Native insects were important pollinators, particularly in unfavourable weather.  相似文献   

8.

Context

Habitat fragmentation generates a loss of functional connectivity detrimental to the persistence of biodiversity. The French agricultural intensification initiated in the 1950s has caused a decline in field margins.

Objectives

As field margins may facilitate species dispersal while providing socio-economic benefits, it is of interest to assess their contribution to the functional connectivity of insect-pollinated plants in agro-ecosystems. This will help develop appropriate management strategies mitigating fragmentation.

Methods

We addressed this issue by studying the links between landscape structure and the patterns of abundance and pollen dispersal (using fluorescent dye particles) for two contrasted insect-pollinated plants occurring in field margins (Crepis sancta and Euphorbia serrata). We investigated the influence of field margins quality and of the surrounding matrix on pollen dispersal and compared the relevance of the least-cost algorithm with a straight-line approach to depict pollinators’ movements.

Results

The influence of landscape structure on plant abundance is species and scale-specific. Pollen dispersal decreases with distance from the source. For E. serrata, it was preferentially dispersed via field margins, confirming the relevance of the least-cost algorithm, while C. sancta dispersal followed a straight-line.

Conclusions

Euphorbia serrata, which grows strictly on field margins with a greater dispersal ability and a more diversified pollinator guild than C. sancta, is less affected by land-use changes. Our study demonstrates the contrasting contributions of field margins to pollen dispersal as they may act as functional corridors favouring pollinators’ movement depending on the species of interest.
  相似文献   

9.
Street trees integrate the urban green infrastructure and are important elements for the maintenance of biodiversity, including pollinators. Thus, assessments of the spatiotemporal distribution and composition of these trees can subsidize strategies of conservation for different groups of pollinators in the cities. Here, we evaluated the spatiotemporal distribution of trees attractive to pollinators across the streetscape of a large Brazilian metropolis with more than 2.5 million inhabitants. We used the georeferenced data of ca. 300,000 woody plant individuals cataloged across the streetscape. These plants were characterized according to their geographical origin, flowering season, and the floral visitor groups that are attracted based on a literature survey. We also tested the “luxury effect” hypothesis on the resource availability to pollinators by evaluating the relationship between the average family income of the population and the richness and abundance of trees. We found that the streetscape was characterized by the dominance of a few tree species, with a balanced representation of both native and non-native species. Bees were the most favored group (94.86%) while bats (1.43%) and moths (1.73%) were the least. The potential supply of resources was homogeneous across dry and wet seasons, but the density of trees was reduced in most of the landscape. We found a strong luxury effect since tree richness and abundance were positively related to regions with higher average family income. Our study highlights the need for better planning and management practices of urban green areas to support pollinators more uniformly across streetscapes. This will allow the benefits provided by pollinators to be more evenly shared among residents of urban landscapes.  相似文献   

10.
Context

Wild flowering plants and their wild insect visitors are of great importance for pollination. Montane meadows are biodiversity hotspots for flowering plants and pollinators, but they are contracting due to tree invasion.

Objectives

This study quantified flowering plants and their flower-visitor species in montane meadows in the western Cascade Range of Oregon. Species diversity in small, isolated meadows was expected to be lower and nested relative to large meadows. Alternatively, landform features may influence richness and spatial turnover.

Methods

Flowering plants and their visitors were sampled in summers of 2011–2017 in twelve montane meadows with varying soil moisture. All flowering plants and all flower-visitors were recorded during five to seven 15 min watches in ten 3?×?3 m plots in each meadow and year.

Results

A total of 178 flowering plant species, 688 flower-visitor species and 137,916 interactions were identified. Richness of flower-visitors was related to meadow patch size, but neither plant nor flower-visitor richness was related to isolation measured as meadow area within 1000 m. Species in small meadows were not nested subsets of those in large meadows. Species replacement accounted for more than 78% of dissimilarity between meadows and was positively related to differences in soil moisture.

Conclusions

Although larger meadows contained more species, landform features have influenced meadow configuration, persistence, and soil moisture, contributing to high plant and insect species diversity. Hence, conservation and restoration of a variety of meadow types may promote landscape diversity of wild plants and pollinators.

  相似文献   

11.
Urban green areas can play a crucial role in establishing spaces that are valuable for pollinators. However, to help ‘pollinator-friendly’ management of urban areas, complete information on the quantity and quality of available floral reward is needed. In this paper, the nectar and pollen of six Cotoneaster species (Rosaceae) were investigated in a two-year experiment established in Lublin city, SE Poland. In temperate climate, Cotoneaster species can ensure nectar and pollen in the full spring period (May/early June) or in early summer (June). A single species can support pollinators on average for 22.9 days. Flowers of Cotoneaster species produce high quantities of nectar (2.27–9.48 mg per flower) and low amounts of pollen (0.11–0.33 mg per flower). On average, the total sugar yield in Cotoneaster species was 11.5 g/m2 (2.3–22.2 g/m2), whereas the total pollen yield was 1.3 g/m2 (0.8–2.8 g/m2). Due to the high potential for total sugar yield, C. macrophyllus, C. lucidus, and C. horizontalis should be recommended to optimize the management of food resources in urban areas. Honeybee was the main insect visitor (70.1 % of the total number of visitors); therefore, Cotoneaster species can be considered valuable for urban beekeepers. However, conservation schemes for bumblebees (21.3 % of the total number of visitors) might also benefit from arrangements with these shrubs. Nevertheless, considering Cotoneaster species in conservation protocols, good-yielding pollen plants should be introduced to compensate for insufficient nutrient intake from pollen in spring.  相似文献   

12.
Summary

Japanese plum (Prunus salicina Lindl.) belongs to the Rosaceae family, which carries the S-RNase-mediated gametophytic self-incompatibility system, which prevents self-fertilisation, and thus promotes out-crossing. The plum cultivar ‘Black Diamond’® has become, one of the most important cultivars in Israel in the last decade, yet its yield is low in comparison with its known potential. Honeybees (Apis mellifera) are the most important pollinators for plums and several studies have demonstrated an apparent relationship between the number of honeybees and the size of the fruit crop. Therefore, in this study, we focussed on improving bee management in a ‘Black Diamond’ orchard. In four consecutive years of experiments, we examined the effects of increasing the density of bee colonies, and of making multiple introductions of colonies, on honeybee activity and on their effectiveness as pollinators of ‘Black Diamond’. We showed that four separate introductions, each of 0.625 colonies ha–1, every 2 – 3 d from 10% full bloom to 3 d after full bloom, with a total density of only 2.5 colonies ha–1, resulted in the greatest level of fruit set.  相似文献   

13.
Semi-natural habitats provide essential resources for pollinators within agricultural landscapes and may help maintain pollination services in agroecosystems. Yet, whether or not pollinators disperse from semi-natural habitat elements into the adjacent agricultural matrix may to a large extent depend on the quality of this matrix and the corresponding pollinator-specific life history traits. To investigate the effects of matrix quality on the distance decay of wild bees and hoverflies, six transects along vegetated field tracks originating at a large semi-natural main habitat and leading into the adjacent agricultural matrix were established in the Wetterau Region, central Hesse, Germany. Species richness of wild bees did not change with distance from the main habitat in landscapes with sufficient grassland cover in the surrounding landscape, but significantly declined when semi-natural grasslands where scarce and isolated in the adjacent agricultural matrix. Abundance of wild bees declined with distance regardless of matrix quality. Species richness of hoverflies did not decline with increasing distance in any landscape. Abundance even increased with distance to the main habitat independently of matrix quality. Thus, our data show that taxa of the pollinator guild may perceive landscapes quite differently. Because of their differing dispersal modes and resource requirements as compared to wild bees, hoverflies may play an important role in maintaining pollination services in agricultural landscapes unsuitable for bee species. Our results highlight the need for considering these taxon-specific differences when predicting the effect of landscape structure on pollinators. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.  相似文献   

14.
Summary

The purpose of this study was to determine the relative importance of honeybee (Apis mellifera) activity and wind in the pollination of avocado (Persea americana Mill.) trees. Data on the pollination rates of five cultivars of avocado, honeybee densities, ambient temperatures, and wind velocities were recorded in an orchard in Israel on 61 d over a period of 7 years. The effect of wind velocity on avocado-flower pollen under laboratory conditions was also studied. Rates of pollination showed highly positive correlations with honeybee density, whereas no correlations were observed with wind velocity. Under laboratory conditions, no effect of wind velocities equivalent to those measured in the field was observed on avocado-flower pollen. Our results agree with earlier work in which wind contributed only slightly to avocado yield. Hence, we conclude that contrasting data which show the effectiveness of wind pollination in avocado are not relevant to most avocado-growing regions, including Israel and California. It is, therefore, strongly recommended that avocado growers continue using honeybees for pollination.  相似文献   

15.

Context

Understanding how landscape patterns affect species diversity is of great importance in the fields of biogeography, landscape ecology and conservation planning, but despite the rapid advance in biodiversity analysis, investigations of spatial effects on biodiversity are still largely focused on species richness.

Objectives

We wanted to know if and how species richness and species composition are differentially driven by the spatial measures dominating studies in landscape ecology and biogeography. As both measures require the same limited presence/absence information, it is important to choose an appropriate diversity measure, as differing results could have important consequences for interpreting ecological processes.

Methods

We recorded plant occurrences on 112 islands in the Baltic archipelago. Species richness and composition were calculated for each island, and the explanatory power of island area and habitat heterogeneity, distance to mainland and structural connectivity at three different landscape sizes were examined.

Results

A total of 354 different plant species were recorded. The influence of landscape variables differed depending on which diversity measure was used. Island area and structural connectivity determined plant species richness, while species composition revealed a more complex pattern, being influenced by island area, habitat heterogeneity and structural connectivity.

Conclusions

Although both measures require the same basic input data, species composition can reveal more about the ecological processes affecting plant communities in fragmented landscapes than species richness alone. Therefore, we recommend that species community composition should be used as an additional standard measure of diversity for biogeography, landscape ecology and conservation planning.
  相似文献   

16.
Metapopulation and optimal foraging theories predict the presence of animals and their duration, respectively, in foraging patches. This paper examines use of these two theories to describe the movements and patterns of foraging in patches used by Caspian gulls (Larus cachinnans) at inland reservoirs during the chick-rearing period. We assumed that birds would move differently across diverse habitats, with some types of land cover less permeable than others, and some landscape features acting as corridors. We also expected larger and less isolated patches, and patches that were close to corridors, to have a higher probability of the presence of foraging birds, and that they would be more abundant, forage for a shorter time, and hunt smaller prey than in small, more isolated patches surrounded by barriers. Forests seem to be a much less permeable type of land cover, whereas rivers became corridors for Caspian gulls during foraging trips. Probability of bird presence was positively related to the size of foraging patches and negatively linked with distance to the nearest river, distance to the nearest foraging patch, and the presence of forests in the vicinity. The same factors significantly affected bird abundance. Contrary to expectations, the duration and success of foraging were not influenced by any variable we measured, suggesting that although larger patches contain a higher abundance of fish, their density and the probability of capturing prey were relatively stable among the various patches. However, gulls that foraged in more isolated ponds that were located further from the river and the colony, and also surrounded by forest, captured larger fish more often than birds that foraged near the colony in less-isolated patches. Pooling metapopulation and optimal foraging concepts seems to be valuable in describing patch use by foraging animals. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.  相似文献   

17.
Widespread ecosystem change has led to declines in species world-wide. The loss of pollinators in particular constitutes a problem for ecosystem function and crop production. Understanding how landscape change affects pollinator movement, effective pollen flow, and plant and pollinator survival is therefore a global priority. In this study we investigated patterns of effective pollen flow, using wild cherry tree (Prunus avium) progeny arrays, to address two questions in three case studies: Do land-use types present different resistances to pollinator movement? Which pollinator travel path best explains the pollination data (straight lines, weighted straight lines, least cost paths or pair-wise resistance)? Trees and progeny arrays were genotyped and effective pollen flow and pollinator movement were estimated using the spatially explicit mating model. We found that pollinators did modify their travel paths in response to land-use type and arrangement, but the travel path that best described pollinator movement and the resistance rank of the land uses depended on the type and size of land-use patches and the landscape context. We propose a novel theoretical framework rooted in behavioural ecology, the resource model, for interpreting pollinator behaviour in heterogeneous landscapes. We conclude by discussing the importance and practicality of conservation and management strategies in which native and non-native land-use types together provide functional habitat and support ecosystem services across economic landscapes.  相似文献   

18.
SUMMARY

Pollinator performance was evaluated in kiwifruit to select pollinators for cv. Hayward adapted to the cultural conditions of southern Europe. Flowering time was determined in forty male seedlings. From, these, nine were selected for having a flowering period overlapping with ‘Hayward’. In these nine males, as well as in the commercial pollinators‘Matua’ and Tomuri’, the production of pollen was studied over two years, investigating pollen quantity through flower density and pollen production per flower. Likewise, in vitro pollen viability and its in vitro germination were recorded to study pollen quality. Finally, in vivo pollen performance was studied through fruit set and fruit characteristics in controlled hand pollinations. Two males have been selected with a flowering period coincident with ‘Hayward’, which produce more than twice as much germinable pollen than commercial pollinators. Whilst there were no significant differences in pollen quality or in fruit production, clear differences existed for pollen quantity in terms of both flower density and pollen production per flower. As pollen quantity, together with flowering time, can be easily evaluated at an early stage, this is encouraging for future selection ofkiwifruit pollinators.  相似文献   

19.
Enhancing knowledge of urban foraging across different urban landscapes is an urgent matter given that about two-thirds of the world’s population is projected to live in urban areas by 2050, whilst 50 % of Africa’s population is expected to live in cities by 2030. This study was conducted in Lagos metropolis which is the economic hub of Africa’s most populous country. Data was collected using an in-person, semi-structured questionnaire from 347 persons who were 18 years or older to identify foragers and non-foragers, their sociodemographic profiles, and their foraging practices. Results revealed that about two out of three persons sampled forage to some degree. The collection happened more in domestic gardens (34 %) and streets (27 %) than in other foraging sites (such as unused lands, institutional grounds and lakes and riparian fringes). A total of 35 species were reportedly foraged within the metropolis, mostly for food (71 %) and medicine (26 %). Mango (Mangifera indica), pawpaw (Carica papaya), tropical almond (Terminalia catappa), fish (various species), bitter leaf (Vernonia amygdalina) and spinach (Spinacia oleracea) were the most gathered species. The distance travelled to foraging wild species ranged from 5 m to 25 km. The primary motivation for foraging was the acquisition of fresh and natural materials. However, some felt that foraging was a stressful activity. The unavailability of foraging sites and species was the major constraint to foraging in this megacity. Hence, efforts to increase the edible components of public green spaces and to provide free access could potentially allow more people to forage and make current foraging more secure. We suggest that making provisions for foraging in urban planning goals could contribute to the sustainable development of cities in Africa and elsewhere.  相似文献   

20.
We investigated the species richness and composition of bird communities in mallee woodland remnants in a highly fragmented landscape, focusing specifically on honeyeaters and their foraging behaviour. We observed birds around flowering Eremophila glabra ssp. glabra plants in three replicated contexts: (1) the interior of large remnants, (2) linear remnants within ~3 km of a large remnant, and (3) linear remnants 5–7 km from a large remnant. We found species richness differed among elements, with an increase in the number of species that tolerate disturbed, open habitat and a decrease in the number of woodland-dependent species in linear elements. Honeyeater assemblages were similar in species richness and abundance among the elements, but differed in composition due to a higher number of large-sized honeyeater species in distant elements. Honeyeater movement patterns into a site and within a site were similar among the elements. Floral visitation varied among honeyeater species and was positively correlated with their abundance in the far element. Our results demonstrate that bird species respond differently to the spatial context of remnants in a fragmented landscape; however, the degree of isolation of linear remnants was not important. Linear remnants appear to be frequently used by honeyeaters, but the changes in community composition among the elements may influence the quality of pollination, which could have implications for plant reproduction.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号