Changes in forest biodiversity metrics associated with Hurricane Katrina

Recurrent tropical cyclones frequently influence warm temperate forests in many coastal regions. If resistance to high winds (cyclone survival) and resilience in altered environments (post-cyclone recruitment) vary with cyclone intensity, then differences in composition, arboreal structure and dynamics of forests should occur in these forests. We hypothesized that major tropical cyclones should produce large, stratum-dependent effects that result in large environmental changes. We anticipate direct regeneration, with post-cyclone forests resembling pre-cyclone forests in composition, but potentially shifting to long-transient alternate states that do not readily or necessarily return to pre-cyclone states. Using a long-term, plot-based study, we explored direct effects of major Hurricane Katrina (sustained winds >50m/sec), as well as initial post-hurricane changes in overstory and understory trees in oak-dominated bottomland and cypress/tupelo-dominated swamp forests within the Missi..., The current study utilized one section of the larger transect to examine changes in forest tree vegetation associated with Hurricane Katrina. In 2004, 20 non-adjacent plots, each 100m2 (10 x 10 m), were randomly established along several hundred m of the transect extending downslope from the top of the western levee of Bayou des Familles to open freshwater marsh. Ten plots were situated in oak-dominated bottomland forest within the more-upland section of the transect that was not flooded in 2004. Ten other plots were situated in seasonally inundated cypress and tupelo-dominated swamp forest. These swamp forest plots were distributed along the transect from upper areas only briefly flooded (1-2 months) to almost permanently flooded areas with numerous hummocks on which woody vegetation was present.
Sampling was conducted four times. We sampled each plot during the summer (August) of 2004 and 2005 (pre-hurricane). We revisited plots for post-hurricane field observations and plot relocatio..., Microsoft Excel