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.