COS 203-4 - Physiological ecology of climate smart native bamboo (Arundinaria gigantae) in U.S.: restoration, conservation, and carbon sequestration in a changing climate

Abstract: Giant cane (Arundinaria gigantea) is a nativre bamboo to 22 states in the U.S and Arundinaria is the only genus native to the U.S. The species and its ecosystem are considered critically endangered and the species has been reduced to 2% of its original extent. The species has a long cultural, commodity and conservation history, and was critical for ecosystem services and biodiversity. In addition, canebrakes can enhance successional trajectories and selective harvesting provides a climate smart commodity. However, re-establishing A. gigantea requires a new understanding of its physiology in a changing climate.

Our goals include establishing greenhouse populations and canebrakes in bottomland forests and riparian areas. Canebrakes will be established for purposes of carbon and nutrient sequestration, bank stabilization, and habitat for insects, birds and mammals. During this process, we are examining the growth and physiology of cane to facilitate establishment and maximize ecosystem processes.

Here we report on the photosynthetic capacity, water use efficiency, chlorophyll content, specific leaf area and water potential as it relates to re-establishing canebrakes. Measurements were obtained over a nine month period in one of the few canebrakes in Missouri that would be a source for restoration plants, in greenhouse propagated cane, and in one planted plot where cane was historically located.

Light saturated photosynthetic rates in the canebrake range in from 14 to 7 umol CO₂/m²/s from March-November independent of sun and shade leaves, with very high constant concentrations of chlorophyll (290-320 umol/m²). The specific leaf area of sun leaves compared to sun leaves is the opposite of expectations from broad leaf trees from the same habitat areas (riparian and bottom land forest). Water potential values during a mild summer drought were -1.7 MPa without any decreases in maximum photosynthetic rates. Being the only evergreen broadleaf species in areas of restoration translates into high carbon and nutrient sequestration over a 12 month period. For example, we estimate that an existing canebrake with a culm density of 50,086 culms currently sequesters 5.8 metric tons of CO₂.

Our data are being used to develop physiologically based models for restoration at multiple sites on private and public lands that are targeted to be restored with native bamboo. We provide estimates of total projected amounts of carbon fixed and stored per ha based on culm density, height and diameter. These estimates inform density dependent planting and maintenance for targeted areas of restoration.