Trait-based approaches to linking vegetation and food webs in early-seral forests of the Pacific Northwest

• Unique vegetative traits of naturally generated early-seral forests may support unique function.
• Specific leaf area is higher among early-seral forests than for later seres.
• Biomass of some primary consumers increase with increasing specific leaf area.
• Functional trait analysis can link disturbance, seral state, and food webs in forests.

Both the structure and composition of naturally generated early-seral forests in the Pacific Northwest (PNW) can be profoundly different than that of more developed forest seres, especially in the period after a major disturbance but before conifers re-develop a closed canopy. While it is reasonable to suggest that the unique structure and composition of early-seral forests in the PNW give rise to equally unique functionality, identifying such linkages beyond that inferred by empirical observation is understandably difficult. To address this challenge, we explore the utility of a trait-based approach to identify the vegetation traits most strongly altered by canopy-opening disturbances (using wildfires as an example), and link these traits to secondary production and subsequent food webs. Preliminary analysis, based on original and literature-derived data, suggests that (1) Lepidoptera production, the primary prey base for forest birds in the PNW, is positively correlated with specific leaf area (SLA) which is higher in stands recently opened by canopy disturbance and (2) small mammal production, an important prey base for meso-predators, is positively correlated with SLA, which is higher in stands recently opened by canopy disturbance. These initial results lay the framework for linking disturbance type, disturbance severity, and subsequent successional pathways to trophic processes uniquely provided by the early-seral condition.

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