I presented artwork studies to have bumble bees at each and every of your own eight web sites into the same about three census periods while we counted floral investment range (twenty-eight Get to help you eight June, 22-30 Summer, 22-30 July). For each and every of one’s about three bumble-bee surveys, we decided to go to for every single website three times, immediately after during each one of three-time episodes (0800-1100, 1100-1300, 1300-1700 circumstances). Most of the sampling are accomplished on the sunny days that have heat anywhere between 19 and you will thirty-two°C.
I caught and you can noted each bumble-bee having a little mark off colored modification liquid on the thorax to stop counting someone more often than once during a sampling several months on an online site. I registered bumble-bee variety, caste, plus the bush variety on what the brand new bumble bee is actually discover foraging and create the new bee. We invested 31 minute for each go to within several internet having a segmet of ?2,000 meters dos , forty five min during the a couple ten,000-meters 2 sites, ninety min within one or two 29,000-yards dos internet, and 120 min during the a few 70,000-meters 2 internet sites. I checked to own a sample big date bias having fun with rarefaction (see Statistical Studies)parisons out-of abundance off bees trapped per hour so you’re able to investment beliefs otherwise habitat sizes got rid of possible testing date biases.
We known bumble bees on the planet using Mitchell (1962) since a primary power; to own meanings away from local types, i used Medler and you can Carney (1963). Hendrix from the School regarding Iowa. Brand new plant kinds have been later categorized while the native or produced to get to know whether the bumble bees, being indigenous, demonstrated preferences getting native flowering types.
Analytical Analyses.
We used the log2 Shannon-Wiener index to calculate bumble bee species diversity using cumulative abundances across all censuses. We also used cumulative abundances of ramets of plant species visited by bumble bees to obtain seasonal totals of available floral resources for each site. Plants included on the list were those from which we captured bumble bees in this and related studies (C. Gienapp, unpublished data). Only rarely did a plant species appear in more than one census, and therefore it is unlikely that the same ramets were counted twice in seasonal abundance measures. We examined plant diversity using the Simpson index rather than the Shannon-Wiener index because the former is less sensitive to rare plant species. These rare species are unlikely to have a strong effect on bumble bee diversity and abundance.
We identified potential predictors of bumble bee variety and variety for each and every time playing with first simple regression analyses comparing them contrary to the payment and you may LRI of any individual and you will shared landscape changeable ( Table dos) within both five hundred- and you will 700-meters radii and you can site parameters (variety, diversity, and you will thickness away from bumble-bee-went to flowering ramets). Landscape predictors demonstrating importance, hence chosen for additional analyses were LRI of your own landscape during the five-hundred and you can 700 m (with and you will without the web site) and also the part of joint grasslands throughout the landscape ( Desk 2). I decided to have fun with LRI thinking that have and you can with no website incorporated to look at the brand new relative efforts from flowery sources of this new landscaping and you will website in itself so you can range and you will wealth including the end result of your landscaping and you can webpages joint. High site predictors was in fact Simpson variety, abundance, and thickness regarding blooming ramets from plant kinds visited of the bumble bees.
Coupon specimens from bumble bees can be found in the fresh new type of Stephen D
I made use of Pearson product-second correlation analyses to look at getting collinearity ranging from possible predictors out-of bumble bee variety and you can abundance by the hour just before multiple regression study. Diversity, variety, and occurrence of flowering ramets at the site just weren’t coordinated toward LRI of the landscape (with and without the web site provided) in the 500- otherwise 700-yards radii (the r 0.16). But not, date hungarian women in us there was weak collinearity amongst the website qualities away from density and variety away from flowering ramets of varieties used by bumble bees (r = 0.668, P = 0.07), and just one among these one or two local measures regarding resources are found in a regression design. In most models, we only use predicators demonstrating zero collinearity (P > 0.10).