Interactive effects of fragmentation and keystone species loss on the structure of a tropical pollination network

破碎化和关键物种丧失对热带授粉网络结构的交互影响

• 批准号: 1457837
• 负责人: Matthew Betts
• 金额: $ 64.16万
• 依托单位: Oregon State University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2015
• 资助国家: 美国
• 起止时间: 2015-07-15 至 2020-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1457837&HistoricalAwards=false
• 关键词: Interactive; effects; fragmentation; keystone; species

Pollination is essential to human well-being, as well as fundamental to maintenance of biological diversity. Research showing large-scale declines of plants and pollinators highlights the concern that pollination services are at risk; the problem arises in part because plant habitat is increasingly fragmented into unconnected patches that pollinators may not be able to reach. However, the pollinators and their plants are interrelated in a network of shared plant species and pollinators and so the functions of hosts and pollinator have redundancy. Fragmentation and loss of native habitats is associated with pollinator declines, but according to theoretical models, the structure of pollination networks is expected to make them generally resilient to change because of the redundancy. However, if plant species that are depended upon by many pollinator species (i.e., "keystone species") are lost, pollination webs may be more vulnerable, resulting in sudden network collapse. This research will address two overarching questions: (1) What are the consequences of keystone plant decline and extinction to the broader pollination network? (2) Can landscape connectivity and consequent greater pollinator movement across patches buffer pollination networks against network collapse? The research itself promotes the progress of science and has implications for national welfare given its potential contributions to the maintenance of pollinator species diversity. Additionally, this work will continue to capitalize on the charisma and diversity of tropical hummingbirds to transmit ideas about the importance of the conservation of pollination services. Previous NSF-funded work has shown that the movement of hummingbird pollinators is strongly restricted by landscape fragmentation, which results in pollen limitation and subsequent regeneration failure in a common keystone forest herb (Heliconia tortuosa). Under the network collapse hypothesis, reduced H. tortuosa densities will limit nectar resource availability thereby decreasing pollinator visitation to fragments and resulting in eventual network collapse. In this instance, landscape connectivity will decrease the minimum number Heliconia required to maintain network structure. Under the robust network hypothesis, the behavioral plasticity of pollinators will confer resistance to the network, even if some plant and hub pollinators are missing or at low abundance. H. tortuosa will be removed from isolated and connected forest fragments to determine whether altered densities of this species affects (a) hummingbird movement, (b) plant reproduction and genetic diversity, and (c) the structure of the pollination network. Hummingbird movement will be quantified for all species in the network using Radio-Frequency Identification Devices (RFID). This method will enable observations of the entire hummingbird pollinator community at an unprecedented temporal resolution (seconds) and spatial scale. Broader impacts will include educational and outreach efforts that include substantial media coverage; international citizen science; educational games and student-driven data collection that meet Next Generation Science Standards; and public education efforts.

授粉对于人类的福祉至关重要，也是维持生物多样性的基础。研究表明，植物和传粉媒介的大规模下降强调了授粉服务处于危险之中的担忧；问题之所以出现，部分是因为植物栖息地越来越分散成授粉媒介无法到达的未连接斑块。但是，传粉媒介及其植物在共享植物和授粉媒介的网络中相互关联，因此宿主和传粉媒介的功能具有冗余。碎裂和本地栖息地的丧失与授粉媒介的下降有关，但是根据理论模型，授粉网络的结构有望使其由于冗余而普遍弹性。但是，如果依赖许多授粉媒介物种（即“基石物种”）的植物物种丢失，则授粉网可能更脆弱，从而导致网络突然崩溃。这项研究将解决两个总体问题：（1）Keystone植物衰落和灭绝更广泛的授粉网络的后果是什么？ （2）景观连通性和随之而来的授粉媒介能否在斑块跨缓冲授粉网络中移动反对网络崩溃？该研究本身促进了科学的进步，并且鉴于其对维持传粉物种多样性的潜在贡献，对国家福利具有影响。 此外，这项工作将继续利用热带蜂鸟的魅力和多样性，以传达有关授粉服务的重要性的想法。以前由NSF资助的工作表明，蜂鸟传粉媒介的运动受到景观碎片的强烈限制，这导致花粉的限制和随后的再生失败（Heliconia tortuosa）。在网络崩溃的假设下，减少的曲调密度将限制花蜜资源的可用性，从而减少授粉媒介对片段的访问，并导致最终的网络崩溃。在这种情况下，景观连接将减少维持网络结构所需的最小数量Heliconia。在强大的网络假设下，即使某些植物和枢纽授粉媒介缺失或较低的丰度，传粉媒介的行为可塑性也将赋予网络抵抗力。将H. tortuosa从孤立和连接的森林碎片中取出，以确定该物种的密度改变是否影响（a）蜂鸟运动，（b）植物繁殖和遗传多样性，以及（c）授粉网络的结构。 使用射频识别设备（RFID），将对网络中的所有物种进行蜂鸟运动。该方法将以空前的时间分辨率（秒）和空间量表来观察整个蜂鸟传粉媒介社区。更广泛的影响将包括包括大量媒体报道的教育和外展工作；国际公民科学；符合下一代科学标准的教育游戏和学生驱动的数据收集；和公共教育工作。