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Responses of Central Amazon Biodiversity and Carbon Storage to Altered Disturbance Regimes

Amanda L. Robertson, Tulane University, (Presenting)
Jeffrey Q. Chambers, Tulane University,
Giuliano P. Guimarães, INPA,
Vilany C. Carneiro, INPA,
Matthew A. Robertson, University of New Orleans,
Lliliane M. Texeira, INPA,
Niro Higuchi, INPA,

Quantifying ecophysiological and structural responses of Amazon forests to global change, although intrinsically difficult, is of urgent concern due to the region’s high biodiversity, carbon budget, and productivity. Global circulation models predict increased storm intensity and drought across Amazonia, resulting in higher occurrence of natural disturbances. Convective storms with powerful microburst winds can damage forests up to 2000 ha per event. Combined with anthropogenic deforestation, the area of secondary forests in Amazonia will increase. This project utilizes an interdisciplinary approach to discern how increasing disturbance regimes in Amazonia will affect biodiversity, species turnover, and carbon storage. We use hyperspectral-remote imaging to locate landscape-scale (e.g. 0.1-30 ha) forest disturbances near Manaus, Brazil. Four endmember spectral mixing analysis (SMA) of non-photosynthetic vegetation (NPV) was used to detect natural forest-canopy damage. Percent canopy damage, stratified into five classes, ranges from 0-100% in 20% intervals. Thirty 400-m2 vegetation plots were established across this canopy disturbance gradient in which stems greater than 5-cm diameter-at-breast-height were measured and identified. Species richness, alpha-diversity, and beta-diversity were calculated between all plot combinations. Species composition, diversity and turnover vary as a function of canopy-damage intensity and gap size. The cost of woody-tissue production is expected to vary with canopy disturbance with the more disturbed plots displaying lower levels of autotrophic respiration. Large-scale natural disturbances initiate a carbon sink, yet frequent and intense disturbances will reduce diversity and carbon-storage potential as low wood-density, early-successional species proliferate. Future projections of Amazon biodiversity and carbon storage must account for altered disturbance regimes.

Science Theme:  LC (Land Use and Land Cover Change)

Presentation Type:  Poster

Abstract ID: 11

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