pollinators limit seed production in an early blooming rare plant: evidence of a mismatch between plant phenology and pollinator emergence

The reproductive ecology of rare plants is seldom studied, yet the persistence of plant populations depends on successful mutualisms with pollinators.  As atmospheric temperatures rise, phenology of plants and pollinators may become mismatched.  We investigated the reproduction of Trifolium barnebyi (Barneby’s Clover), a mat-forming perennial endemic to central Wyoming, USA that grows in the crevices of sandstone bedrock.  Our objectives were to evaluate a method for monitoring changes in cover as well as assess the pollination and seed-set of T. barnebyi.  We established five monitoring transects using a divided frame to estimate percent cover.  We conducted seed-set experiments at three locations to measure self-pollination and the degree to which pollinating insects limited seed production.  We used vane traps and bee bowls to capture pollinators, and examined pollen carried on bees.  Percent cover along transects declined over the 4 year period and was associated with spring precipi..., Monitoring To assess the cover and asexual reproduction of T. barnebyi, we monitored five transects annually in July between 2018 and 2021. We established two transects at the Weiser Knoll site (Weiser Slope and Weiser Seedlings) and the Hall Creek site (Hall 1 and Hall 2), and one transect at South Red Canyon (Fig. 1). Each transect consisted of a belt between 6.9 and 18 m in length where a plot frame (30 x 30 cm) with sixteen 7.5 x 7.5 cm cells was placed on the ground along the belt to assess cover (Fig. 2). We used a plot frame to monitor T. barnebyi because the compact and extensive mats of this species make distinguishing individuals difficult without destructive sampling. We placed the plot frame on one side of the belt at all sites expect South Red Canyon and Weiser Knoll Seedling, where we placed the frame above and below the belt. We counted the number of cells with T. barnebyi present within each frame at 30 cm intervals. Cells were scored as present (1) or absent (0) to ..., All analyses were done in Program R (R Core Team 2017)., # Trifolium barnebyi pollination and monitoring ## Description of the data and file structure 2021TrifoliumBarnebyiClimateAndMonitoringData.csv Monthly temperature in degrees Fahrenheit and total precipitation in inches in Lander Wyoming (nearest weather station; https://wrcc.dri.edu/cgi-bin/cliMAIN.pl?wy5390); Spring precipitation totals in inches; Percent occupied cells in monitoring frame by location; All by year 2018-2021 no NA values 2021TrifoliumBarnebyiSeedSet.csv has the seed set treatment, number of flowers, number of viable seeds, day of year harvested, location of plant. Variables: * Treatment (Bagged = pollinators excluded from flowerhead throughout blooming, HP = hand pollinated with extra pollen with pollinator access throughout blooming, Open = pollinator access throughout blooming); * PlantNo (unique plant identifier); * NoFlower (number of flowers on flowerhead); * NoOvules (number of ovules in the flowerhead); * OvulesPerFlw (mean ovules per flower in the flowe...稀有植物的繁殖生态学鲜有研究，但植物种群的存续依赖于与传粉者之间成功的互利共生关系。随着大气温度升高，植物与传粉昆虫的物候可能出现错配。本研究针对巴内比三叶草（Trifolium barnebyi，Barneby’s Clover）开展繁殖相关调查，该物种为垫状多年生草本，为美国怀俄明州中部特有种，生长于砂岩基岩缝隙中。本研究的目标为：一是评估用于监测盖度变化的方法，二是评估巴内比三叶草的传粉与结籽情况。我们采用分格样方框设置了5条监测样带以估算盖度百分比；在3个位点开展结籽实验，以衡量自交情况以及传粉昆虫对种子生产的限制程度；使用风动诱捕器与蜜蜂碗诱捕器采集传粉昆虫，并检测蜜蜂携带的花粉。样带的盖度在4年研究期间呈下降趋势，且与春季降水... 监测 为评估巴内比三叶草的盖度与无性繁殖情况，我们于2018至2021年每年7月对5条样带开展监测。我们在韦泽尔丘（Weiser Knoll）样地（包含韦泽尔坡与韦泽尔幼苗样线）与霍尔溪（Hall Creek）样地（包含Hall 1与Hall 2样线）各设置2条样带，在南红岩峡谷（South Red Canyon）设置1条样带（图1）。每条样带包含一条长6.9至18米的样带段，沿样带段地面放置带有16个7.5×7.5厘米格子的30×30厘米样方框以评估盖度（图2）。我们采用样方框开展巴内比三叶草监测，原因在于该物种紧凑且延展的垫状群落若不进行破坏性采样，难以区分单个个体。除南红岩峡谷与韦泽尔丘幼苗样线外，其余所有样地均将样方框放置于样带段的一侧；而上述两个样地则将样方框放置于样带段的上方与下方。我们以30厘米为间隔，统计每个样方框内存在巴内比三叶草的格子数量。格子以存在记为1、不存在记为0进行计分... 所有数据分析均在R程序（R Core Team 2017）中完成。 # 巴内比三叶草传粉与监测 ## 数据与文件结构说明 `2021TrifoliumBarnebyiClimateAndMonitoringData.csv`：怀俄明州兰德市（最近的气象站；https://wrcc.dri.edu/cgi-bin/cliMAIN.pl?wy5390）的月均气温（华氏度）、总降水量（英寸）、春季降水总量（英寸）、各监测位点的样方框占据格子百分比，数据时间跨度为2018至2021年，无缺失值。 `2021TrifoliumBarnebyiSeedSet.csv`：包含结籽处理组、花头花朵数量、饱满种子数量、收获日期（一年中的第几日）、植株采样位点信息。 变量说明： * `Treatment`（处理组）：Bagged（套袋处理：整个开花期内排除传粉者访问花头）、HP（人工授粉处理：整个开花期内允许传粉者访问并补充额外花粉）、Open（开放处理：整个开花期内允许传粉者自由访问）； * `PlantNo`：植株唯一标识符； * `NoFlower`：花头的花朵数量； * `NoOvules`：花头的胚珠数量； * `OvulesPerFlw`：单花平均胚珠数量（原文截断为`flowe...`）