Different bee-flower survey methods impact conservation recommendations: comparing citizen science and academic surveys

by Visser et al.

Helping wild bees thrive in cities is important, especially as urbanisation threatens their numbers and diversity. One way to support bees is by planting the right flowers, but figuring out which ones work best takes a lot of data and the right tools.

In this study, we used a special tool designed to suggest flower combinations that attract the greatest variety of wild bees. We looked at bee-flower interaction data from Brussels (Belgium), using two very different sources: (1) observations from everyday people (citizen science), and (2) data from formal scientific surveys.

We found that the source of the data made a big difference in which flowers were recommended. The two types of data led to flower mixes that were only 7% similar, meaning most of the recommended flowers were different depending on which data was used. This shows that how we collect data can really shape our conservation advice.

To make this approach more accessible, we created a free app that anyone can use to design flower mixes that help pollinators, whether they want to boost bee numbers, support more bee species, or both. Users can base their choices on our data or upload their own.

Read the scientific paper in JPE 

The concentration and energetic content of floral nectar sugars: calculation, conversions, and common confusions

by Pattrick et al.

Refractometers for sugar measurements

Floral nectar mediates the interactions between plants and pollinators. It is the main reason many pollinators visit flowers.  Nectar composition is dominated by sugars – most commonly sucrose, fructose and glucose – which make nectar a carbohydrate-rich energy source for floral visitors.  The sugar concentration of nectar is therefore a key metric which defines how energy rich a particular nectar is.  There are multiple methods of describing the concentrations and relative proportions of the constituent sugars in nectar.  A potential source of confusion in pollination biology research is that several of these methods are commonly expressed as percentages, ratios or proportions and so can give the appearance of describing the same parameter when they are actually completely different measures.  Furthermore, without prior knowledge that these different approaches exist, it is easy to confuse the different methods.  Here we aim to bring clarity to this topic, consolidating previous work to describe the most commonly used methods for reporting sugar concentrations and how they differ.  We offer suggestions for reporting these values to improve clarity and provide equations for converting between methods.  We also present worked examples on how to calculate the energetic content of sugars in nectar and discuss how the relative energetic content of nectar varies depending on the respective proportions of the constituent sugars.  We hope that this manuscript serves as a useful resource for pollination biologists. 

 

Read the scientific article in JPE. 

Rare plant’s need for native pollinators threatened by invasive plant-pollinator relationship

Chloropyron maritimum ssp. maritimum
visited by Bombus californicus.
Photo: Kylie Etter

By Etter et al.

Many flowering plants need pollinators like bees to reproduce. But when new, non-native plants move into their habitats, they can disturb these important relationships. One rare plant that is reliant on pollinators is Chloropyron maritimum maritimum, which is found in salt marshes in Southern California, USA and Baja California, Mexico. Unfortunately, these marshes are being invaded by a non-native plant called Limonium duriusculum.

To see how this invasion affects the rare plant, we watched which insects visited which flowers, studied the network of plant-pollinator relationships, and tested what happened when L. duriusculum was removed in small areas.

We found that only native bees visited C. maritimum maritimum, and not very often. In contrast, L. duriusculum was mostly visited by two non-native insects, which didn’t once visit the rare plant. Removing L. duriusculum didn’t increase visits to C. maritimum maritimum, but it did make the overall pollination network stronger and more connected.

In the future, we hope to both remove larger areas of the non-native plant and check to see if there are good places nearby for the native bees that visit C. maritimum maritimum to nest. This could help protect the few remaining pollination interactions the rare plant still has.

 

Read the scientific article in JPE!