We conducted visual surveys to possess bumble bees at each and every of seven websites within the exact same about three census episodes even as we counted floral financing variety (twenty-eight Will get to eight Summer, 22-31 June, 22-30 July). Per of around three bumble bee studies, we visited for each and every web site 3 times, immediately after during the each one of three-time episodes (0800-1100, 1100-1300, 1300-1700 instances). Every sampling are achieved into bright days having heat anywhere between 19 and you will thirty-two°C.
I trapped and you will noted for every bumble bee having a small mark out of colored correction water with the thorax to prevent counting somebody more than once throughout a sampling months on web site. I filed bumble-bee varieties, caste, and also the plant types on which the fresh bumble bee is actually receive foraging and released new bee. I invested 30 minute for every single check out from the a couple of sites that have an area of ?2,000 m dos , forty five minute from the several ten,000-yards dos internet, ninety minute at the a couple of 30,000-yards dos websites, and you may 120 minute within a few 70,000-meters dos sites. I checked out to possess a sample day prejudice playing with rarefaction (discover Analytical Data)parisons out-of wealth regarding bees trapped hourly in order to money thinking or habitat versions eliminated potential testing go out biases.
I identified bumble bees worldwide playing with Mitchell (1962) once the a first authority; to own meanings out-of local variety, i used Medler and you may Carney (1963). Hendrix at School from Iowa. New bush types have been later on classified as the native otherwise put to familiarize yourself with perhaps the bumble bees, being indigenous, displayed needs to own indigenous flowering variety.
Mathematical 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 Plants included on the list were those from which we captured bumble bees in this and related studies (C. Gienapp, unpublished data).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 understood potential predictors out-of bumble-bee range and you will abundance for every single hr using first simple regression analyses evaluating them resistant to the fee and you will LRI of each and every individual and you will joint landscape adjustable ( Table 2) in the each other five hundred- and you can 700-yards radii and you may site parameters (abundance, range, and you can thickness out of bumble bee-went to flowering ramets). Landscape predictors exhibiting advantages, and this selected for further analyses had been LRI of landscaping from the 500 and you will 700 m (with and you may with no webpages) and also the part of joint grasslands on the land ( Desk dos). I chose to play with LRI values with and without any webpages provided to look at the brand new cousin contributions off floral resources of the new landscaping sexy Jodhpur girl and you may website in itself so you’re able to range and you may abundance also the effect of land and website shared. Significant website predictors was Simpson diversity, abundance, and you may density of blooming ramets regarding plant kinds went along to from the bumble bees.
Coupon specimens from bumble bees are located in this new line of Stephen D
We used Pearson product-time correlation analyses to look at to possess collinearity anywhere between prospective predictors from bumble bee assortment and variety by the hour ahead of several regression study. Diversity, wealth, and you will density out of blooming ramets from the site just weren’t coordinated towards LRI of landscaping (that have and you will without the webpages included) during the five-hundred- otherwise 700-m radii (most of the r 0.16). Yet not, there’s weak collinearity amongst the webpages properties off occurrence and you may variety off flowering ramets regarding kinds used by bumble bees (roentgen = 0.668, P = 0.07), and just one of them one or two regional methods out-of resources is found in any given regression design. In every designs, we only use predicators exhibiting zero collinearity (P > 0.10).
