Discipline: Ecology Environmental and Earth Sciences
Elizabeth Hedrick - Lincoln University
Co-Author(s): David Heise, Lincoln University, MO
The ecological contributions of native bees as pollinators are unparalleled, yet while bee-pollinated crop production increases, significant declines in insect pollinators have been widely documented. Such declines make non-invasive monitoring methods increasingly important. Also, accurate and efficient methods for gathering valuable wild bee population data are limited. Bees exhibit characteristic flight buzz frequencies that vary with their size, species, and caste, suggesting that passive acoustic monitoring may offer a non-invasive method for more convenient monitoring of bee communities. However, buzz variance within bee species may make acoustically differentiating dozens of individual species in situ difficult. Research shows that wild bee diversity is closely associated with, and essential for, sustaining pollination services; therefore, some estimate of bee diversity may be a useful and simpler first step towards a monitoring system. We have developed algorithms that extract bee flight buzz abundances and diversity of buzz frequencies in field recordings, and we hope to determine whether there is a correlation between buzzes and bees as the community changes over time. If successful, buzz diversity might serve as a possible supplement or proxy for time-consuming, manual measurements of bee diversity. Preliminary data is being collected biweekly in the Overton Bottoms South Unit of the USFWS Big Muddy Wildlife Reserve. Audio recordings are taken concurrently (on consecutive days, as weather permits) with manual netting and trapping (per USGS standard) to provide ground truth. Recording and collection days are separate to avoid removing bees from the system during recordings. Changes in bee abundance and diversity will be monitored through October 2016 to allow correlation with buzz abundance and diversity data automatically extracted from the acoustic recordings. Abundance and diversity of other local buzzing insects (e.g. flies, wasps) will be taken into consideration and analyzed separately, with some work towards differentiating bee buzzes from non-bee buzzes. The effects of changing daily temperature and floral community within the plot will also be considered. Once in the analysis phase (Fall 2016), we will primarily use our algorithms for analysis, but will manually annotate selected data to use as ground truth for comparison to software outputs. We expect to find that our acoustic monitoring system shows trends similar to those seen in ground truth. More extensive data will be collected Summer 2017, followed by a final analysis and evaluation of the viability of our monitoring system.
References: Klein A-M, Steffan-Dewenter I, Tscharntke T. 2003. Fruit set of highland coffee increases with the diversity of pollinating bees. Proc. R. Soc. Lond. 270:955-961.
Kremen C, Williams NM, Thorp RW. 2002. Crop pollination from native bees at risk from agricultural intensification. Proc. Natl. Acad. Sci. USA. 99:16812-16816.
Funder Acknowledgement(s): This study was supported by the National Science Foundation: (HBCU UP) Award # HRD-1410586 to David Heise, Lincoln University, Jefferson City MO 65101; and Award # IIA-1355406 to John Walker, University of Missouri, Columbia, MO 65211.
Faculty Advisor: David Heise, HeiseD@lincolnu.edu
Role: Literature review, experimental design and development, data collection, and analysis.