Predicting landscape-scale native bumble bee habitat use over space, time, and forage availability.

Area of Science:

• Ecology
• Conservation Biology
• Landscape Ecology

Background:

• Foraging resource distribution is critical for animal habitat use and survival.
• Agricultural expansion and exotic species have altered resource availability in space and time.
• Fragmented landscapes necessitate new methods to study mobile organism resource utilization.

Purpose of the Study:

• To characterize how bumble bee resource availability and use change with landscape composition and season.
• To identify spatiotemporal patterns of bumble bee resource use in diverse agricultural regions.
• To develop a novel framework for predicting insect resource use in fragmented landscapes.

Main Methods:

• Deployed native bumble bee (Bombus vosnesenskii) colonies across habitat types and a land-use gradient.
• Employed a probabilistic framework to analyze pollen foraging patterns and plant availability.
• Quantified resource preference and availability relative to landscape composition and season.

Main Results:

• Bumble bee pollen foraging preference and availability were strongly influenced by landscape composition and time of year.
• Bees showed a significant preference for native plants, which were overrepresented in samples.
• A strong reliance on seminatural habitats (oak savannahs, chaparral, riparian corridors) was observed, even in intensive agricultural areas.

Conclusions:

• Mosaic landscapes, characterized by heterogeneity, are vital for bumble bees to connect resources throughout the season.
• Even in highly agricultural landscapes, bumble bees utilized interstitial habitats for foraging.
• The developed framework enhances predictions of insect resource use in fragmented environments.