Resource waves: phenological diversity enhances foraging opportunities for mobile consumers

Abstract

Time can be a limiting constraint for consumers, particularly when resource phenology mediates foraging opportunity. Though a large body of research has explored how resource phenology influences trophic interactions, this work has focused on the topics of trophic mismatch or predator swamping, which typically occur over short periods, at small spatial extents or coarse resolutions. In contrast many consumers integrate across landscape heterogeneity in resource phenology, moving to track ephemeral food sources that propagate across space as resource waves. Here we provide a conceptual framework to advance the study of phenological diversity and resource waves. We define resource waves, review evidence of their importance in recent case studies, and demonstrate their broader ecological significance with a simulation model. We found that consumers ranging from fig wasps (Chalcidoidea) to grizzly bears (Ursus arctos) exploit resource waves, integrating across phenological diversity to make resource aggregates available for much longer than their component parts. In model simulations, phenological diversity was often more important to consumer energy gain than resource abundance per se. Current ecosystem-based management assumes that species abundance mediates the strength of trophic interactions. Our results challenge this assumption and highlight new opportunities for conservation and management. Resource waves are an emergent property of consumer-resource interactions and are broadly significant in ecology and conservation.

The greenscape shapes surfing of resource waves in a large migratory herbivore

“…Resource waves should favour movement strategies where animals match their movements with resources as they propagate across the landscape (Armstrong et al . ). From grizzly bears ( Ursus arctos ) pursuing sockeye salmon ( Oncorhynchus nerka ) across spawning sites (Schindler et al .…”

The complementary role of lentic and lotic habitats for Arctic grayling in a complex stream‐lake network in Arctic Alaska

“…At the individual scale, research is needed to better understand how fish move between and use connected stream and lake environments. Lastly, resources available in complementary lentic and lotic habitats may also have strong temporal variation, allowing individuals and populations to track "resource waves" across space and time (Armstrong, Takimoto, Schindler, Hayes, & Kauffman, 2016). Lastly, resources available in complementary lentic and lotic habitats may also have strong temporal variation, allowing individuals and populations to track "resource waves" across space and time (Armstrong, Takimoto, Schindler, Hayes, & Kauffman, 2016).…”

Consumer trophic positions respond variably to seasonally fluctuating environments

“…, Armstrong et al. ). Floodplain‐derived resources might be relatively ephemeral at any given location (e.g., rice field; Fig.…”

“…), but widely available for a mobile consumer capable of “surfing” these peaks across the landscape (Armstrong et al. ). Even brief access to floodplain resources is known to support fish production (Jardine et al.…”