We used graphic surveys to possess bumble bees at each and every of eight sites in exact same around three census periods while we measured flowery financing diversity (28 Get so you’re able to seven Summer, 22-29 Summer, 22-30 July). Each of your three bumble-bee studies, i went to for each and every webpages 3 x, shortly after during the every one of three time symptoms (0800-1100, 1100-1300, 1300-1700 days). Most of the sampling is actually carried out towards bright days having heat between 19 and you will thirty two°C.
I trapped and you will noted per bumble bee which have a small dot from colored modification liquid to your thorax to eliminate depending some one more than once during a sample months from the a web site. I filed bumble-bee kinds, status, plus the plant varieties on which the bumble bee is discover foraging and you may put out the fresh new bee. We invested 31 min per check out at a few sites with an area of ?dos,000 m 2 , forty-five min at the two 10,000-m 2 web sites, ninety min in the several 30,000-yards dos websites, and you may 120 min at one or two 70,000-meters dos websites. I checked-out having a sample go out bias playing with rarefaction (discover Analytical Studies)parisons regarding abundance out-of bees trapped by the hour in order to capital viewpoints or environment versions removed possible sampling big date biases.
I understood bumble bees around playing with Mitchell (1962) since the a primary expert; to possess descriptions out-of regional species, we used Medler and you can Carney (1963). Hendrix on College from Iowa. The newest bush kinds was later on categorized since the native otherwise lead to help you analyze perhaps the bumble bees, that are native, presented choices having native blooming kinds.
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 Plants included on the list were those from which we captured bumble bees in this and related studies (C. Gienapp, unpublished data).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.
I identified potential predictors out of bumble-bee range and you may variety for every time playing with preliminary simple regression analyses comparing them resistant to the fee and you can LRI of any personal and mutual landscape adjustable ( Table dos) on each other five-hundred- and you will 700-yards radii and you can website parameters (abundance, assortment, and you can thickness from bumble-bee-visited flowering ramets). Landscaping predictors indicating advantages, hence chose for further analyses was basically LRI of one’s landscape on 500 and you will 700 yards (which have and you may without any webpages) plus the percentage of combined grasslands on the land ( Table dos). I decided to use LRI values with and you can without any site integrated to examine the fresh new cousin contributions out of floral sourced elements of this new landscaping and you can webpages alone so you can variety and abundance as well as the end result of landscape and webpages combined. Tall website predictors have been Simpson range, wealth, and you will thickness out of flowering ramets away from plant variety decided to go to because of the bumble bees.
Coupon specimens out-of bumble bees come into brand new collection of Stephen D
We put Pearson equipment-minute correlation analyses to look at getting collinearity ranging from possible predictors regarding bumble bee assortment and abundance by the hour ahead of several regression analysis. Assortment, wealth, and you can occurrence out-of flowering ramets during the website were not coordinated to the LRI of landscaping (having and you can without having any web site integrated) from the 500- or 700-yards radii (the roentgen 0.16). But not, you will find weakened collinearity between your website properties out-of thickness and you may wealth out Bhopal women sexy of flowering ramets off kinds employed by bumble bees (r = 0.668, P = 0.07), and simply one of those a few local methods off info is actually included in any given regression design. In all designs, i use only predicators proving zero collinearity (P > 0.10).