Pollinator visitation, flower count, and seed set in Black Sand plots, 2020.

Anthropogenic climate change is altering interactions among numerous species, including plants and pollinators. Plant-pollinator interactions, crucial for the persistence of most plant and many insect species, are threatened by climate change-driven phenological shifts. Phenological mismatches between plants and their pollinators may affect pollination services, and simulations indicated that these mismatches may reduce floral resources available to up to 50% of insect pollinator species. Although alpine plants rely heavily on vegetative reproduction, seedling recruitment and seed dispersal are likely to be important drivers of alpine community structure. Similarly, advanced flowering may expose plants to increased risk of frost damage and shifted soil moisture regimes; phenologically advanced plants will experience these environmental factors differently, which may alter their floral resource production. These effects may be dependent upon topography. Some species of alpine plants on the Niwot Ridge have displayed advanced phenology under treatments of advanced snowmelt (Forrester, 2021). However, little is understood about how these differences in distribution and phenology affect pollinator community composition and plant fecundity. Here we strive to examine how experimentally-induced changes in the timing of flowering and number of flowers produced by plants impact plant-pollinator interactions and seed set. We also ask how topography and the number of flowers interact with early snowmelt to affect pollination rates and the diversity of pollinating insects. Finally, we ask how seed set of Geum rossii is affected by pollinator visitation at different times of the season, under experimentally advanced snowmelt versus unmanipulated snowmelt, and with visitation by different insect taxa. In summer 2020, we found that plots with advanced phenology experienced peaks in pollinator visitation rates and pollinator diversity earlier than plots with unmanipulated snowmelt. We expect this to be because of the advanced floral phenology of certain key species in these plots. References: Forrester, C.C. (2021). Advancing, Using, and Teaching Climate Change Ecology Research. [Doctoral dissertation, University of Colorado, Boulder]. ProQuest Dissertations and Theses.人为气候变化正在改变众多物种间的种间相互作用，涵盖植物与传粉者（pollinator）。植物-传粉者互作（plant-pollinator interaction）对多数植物类群与诸多昆虫物种的存续至关重要，却正受气候变化驱动的物候转变（phenological shift）威胁。植物与传粉者间的物候错配（phenological mismatch）或会干扰传粉服务；模拟研究表明，此类错配可能导致多达50%的昆虫传粉者可利用的花资源锐减。 尽管高山植物（alpine plant）高度依赖营养繁殖，但幼苗建成与种子扩散仍可能是塑造高山植物群落结构的关键驱动因子。与之类似，开花物候提前会使植物面临更高的霜冻损害风险，同时改变土壤水分状况；物候提前的植物将受到这些环境因子的差异化影响，进而可能改变其花资源的产出水平。此类效应可能受地形条件调控。尼沃特岭（Niwot Ridge）上的部分高山植物物种在提前融雪的实验处理下已表现出物候提前现象（Forrester, 2021）。 然而，学界对这类分布与物候的差异如何影响传粉者群落组成及植物繁殖力仍知之甚少。本研究旨在探究三大问题：其一，实验诱导的植物开花时间与花数量变化，如何影响植物-传粉者互作与结实率（seed set）；其二，地形与花数量如何与早融雪交互作用，影响传粉效率与传粉昆虫的多样性；其三，在实验提前融雪与未人为干预融雪的条件下，不同季节时段的传粉者访花（pollinator visitation）以及不同昆虫类群的访花活动，如何影响罗斯氏路边青（Geum rossii）的结实率。 2020年夏季的观测结果显示，物候提前的样地，其传粉者访花率与传粉者多样性的峰值出现时间，早于未人为干预融雪的对照样地。我们推测这一现象源于这些样地中部分关键物种的开花物候提前。 参考文献：Forrester, C.C. (2021). 《推进、应用与讲授气候变化生态学研究》[博士学位论文，科罗拉多大学博尔德分校]. ProQuest学位论文全文数据库。