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Contrasting floral visitation with pollination: single-visit pollen deposition generates true pollinator networks, with implications for conservation

对比花卉访问与授粉：单次访问花粉沉积产生真正的传粉者网络，对保护具有影响

基本信息

批准号：
NE/K004522/1
负责人：
Pat Willmer
金额：
$ 72.39万
依托单位：
University of St Andrews
依托单位国家：
英国
项目类别：
Research Grant
财政年份：
2013
资助国家：
英国
起止时间：
2013 至无数据
项目状态：
已结题

来源：
https://gtr.ukri.org/projects?ref=NE%2FK004522%2F1
关键词：
Contrasting floral visitation pollination single

项目摘要

We will construct true pollination networks in three plant communities (each with previously published visitation networks), by recording pollen deposition onto stigmas by flower visitors, thus establishing the pollinator effectiveness of individual species and allowing the first direct comparisons of visitation and pollination networks. In recent years network-based approaches have greatly enhanced our understanding of the links among species in terms of both mutualistic and antagonistic relationships. Plant-pollinator interactions are the most widely studied mutualism at the community level, and construction of flower-visitation networks has moved pollination ecology beyond traditional one plant-one visitor studies. A network-approach is vital for predictions of how communities respond to climate change, to introduced non-native species, and to species extinction, and is important for conservation of natural ecosystems and maintained pollination as an ecosystem service to underpin food security. In one respect, however, existing networks are limited. Flower visitation networks do not equate to flower pollination networks, since not all visitors effectively transfer conspecific pollen to a receptive stigma, as required for fertilisation and seed set. Furthermore, many flower visitors cheat, taking pollen or nectar without providing a pollination service. Our pilot studies show that only a proportion of visitors do transfer conspecific pollen, this proportion varying markedly between plant species. Visitation networks may therefore under-emphasise the specialisation of plant-pollinator interactions.The inclusion of a measure of pollinator effectiveness in visitation networks is thus essential to prove pollinator functionality and ensure appropriate use of such networks in modelling complex ecological interactions. Our pilot work confirms that single visit pollen deposition (SVD), by a flower visitor onto a receptive stigma, provides an ideal and practical measure of individual pollinator effectiveness. SVD can then be combined with flower visitation frequency to build a more accurate and realistic picture of pollinator importance for a particular plant species.In this project we will measure the pollination effectiveness, as SVD, of visitors to flowers (at the species level) in previously published visitation networks at sites chosen for the quality of existing data and for varying environmental impacts: low diversity UK heathland, very high diversity Israeli pine forest, and moderate diversity Kenyan savannah. At each site we will collect data to allow daily temporal resolution to be incorporated in networks, revealing how pollinator effectiveness varies on a daily timescale, in relation to pollen availability, nectar resources, and associated microclimate variation. This work will enable us to generate true pollination networks, and to answer key questions regarding the usefulness of current visitation networks:1) How do visitation and pollination networks correspond and/or differ in their predictions of community specialisation, and how does this vary with different visitor and flower diversities? From this, better appreciation of the relative value of existing networks can be achieved. 2) How great is the variation in pollinator effectiveness within functional groups of visitors? Do networks constructed at the species level differ, and do they again vary with site diversity?3) How well can other measurements, already used as proxies by some authors adequately predict pollinator effectiveness?4) How are predictions of network stability, and the associated consequences of species extinction, altered by inclusion of more robust pollinator effectiveness data into networks?The answers to these questions will have important implications for the future use of plant-pollinator networks in conservation policy decisions, and will provide valuable support for projects in NERC's Insect Pollinators Initiative.

我们将通过记录访花者在柱头上的花粉沉积，在三个植物群落（每个群落都有先前发表的访花网络）中构建真实的传粉网络，从而建立单个物种的传粉者有效性，并允许首次直接比较访花和传粉网络。近年来，基于网络的研究方法极大地增强了我们对物种间互惠关系和对抗关系的理解。植物与传粉者的相互作用是在群落水平上研究最广泛的相互作用，花访网络的构建使传粉生态学超越了传统的一株一访研究。网络方法对于预测群落如何应对气候变化、引入的非本地物种和物种灭绝至关重要，对于保护自然生态系统和维持授粉作为支撑粮食安全的生态系统服务也很重要。然而，在一个方面，现有的网络是有限的。花的访问网络并不等同于花的授粉网络，因为并不是所有的访问者都能有效地将同株花粉转移到受精卵柱头上，这是受精和定子所必需的。此外，许多访花者欺骗，取花粉或花蜜而不提供授粉服务。我们的初步研究表明，只有一定比例的访花者会传递同种花粉，这一比例在植物物种之间变化显著。因此，访问网络可能低估了植物与传粉者相互作用的专门化。因此，在访问网络中纳入传粉者有效性的测量对于证明传粉者的功能和确保在模拟复杂的生态相互作用时适当使用这种网络至关重要。我们的试点工作证实，单访花花粉沉积（SVD），由一个花的访问者到接受柱头，提供了一个理想的和实用的衡量个体传粉者的有效性。然后SVD可以与花的访问频率相结合，以建立一个更准确和真实的传粉者对特定植物物种重要性的图像。在这个项目中，我们将根据现有数据的质量和不同的环境影响，在先前公布的访问网络中，测量花的游客（在物种水平上）的授粉效率（SVD）：低多样性的英国石南草原，非常高多样性的以色列松林和中等多样性的肯尼亚大草原。在每个站点，我们将收集数据，以便将每日时间分辨率纳入网络，揭示传粉者的有效性如何在每日时间尺度上变化，与花粉可用性，花蜜资源和相关的小气候变化有关。这项工作将使我们能够生成真正的授粉网络，并回答有关当前访问网络有用性的关键问题：1)访问和授粉网络如何对应和/或不同于他们对社区专业化的预测，以及这如何随着不同的访问者和花卉多样性而变化？由此，可以更好地评估现有网络的相对价值。2)在不同的游客功能群中，传粉者的有效性差异有多大？在物种水平上构建的网络是否不同，它们是否会随着地点的多样性而变化？3)一些作者已经使用的其他测量方法能在多大程度上充分预测传粉者的有效性？4)将更可靠的传粉者有效性数据纳入网络，如何改变网络稳定性的预测以及物种灭绝的相关后果？这些问题的答案将对未来在保护政策决策中使用植物传粉媒介网络具有重要意义，并将为NERC昆虫传粉媒介倡议的项目提供宝贵的支持。