While biodiversity may be the basis of resilience, it is not the only foundation for resilience. Ecosystems depend also on physical, structural characteristics to keep from being overwhelmed. Some examples:
· In the aftermath of the tsunami hitting the coast of Indonesia in December 2004 aerial photography revealed that some parts of the coast were hit harder than others. Research subsequently demonstrated that the coast suffered less damage where the offshore reef was intact. Apparently, many reefs areas around the Indian Ocean have been exploded with dynamite because they are considered impediments to shipping, an important part of the South Asian economy. Similarly, the removal of coastal mangrove trees (for residential development) is believed to have intensified the effect of the tsunami in some locations. http://en.wikipedia.org/wiki/2004_Indian_Ocean_earthquake
Damage from the tsunami was reduced by the presence of an extensive, intact mangrove fringe. 2005, Danielson et al. Science 310:643 “The Asian Tsunami: a protective role for coastal vegetation”
· In the aftermath of Katrina, the hurricane that made landfall August 29 2005 in southeast Louisiana, USA, it was shown that where the offshore mudflats were more intact, the impact of the storm was reduced. “Barrier islands, shoals, marshes, forested wetlands, and other features of the coastal landscape can provide a significant and potentially sustainable buffer from wind wave action and storm surge generated by tropical storms and hurricanes. Anecdotal data accumulated after Hurricane Andrew suggest that a storm surge reduction along the central Louisiana coast of about three inches per mile of marsh… Emergent canopies such as provided by forested wetlands can greatly diminish wind penetration, thereby reducing the wind stress available to generate surface waves and storm surge. Shallow water depths attenuate waves via bottom friction and breaking…” pp3,15 2006-Jan-26, Working Group for Post-Hurricane Planning for the Louisiana Coast, A New Framework for Planning the Future of Coastal Louisiana after the Hurricanes of 2005.
· In the coastal forest extending from the Canadian west coast into the American pacific northwest the bark near the forest floor of Redcedars, Douglas-firs, Redwoods, and other large trees is thick enough to be able to withstand small fires, such as would occur naturally by lightning and that would consume the local underbrush. Where a fire suppression policy is in place, underbrush builds up – providing fuel for a potentially large and hot fire – which might be hot enough to destroy the large trees. The Oakland Hills fire of 1991 was at least in part a result of this condition: “At the fires peak it would destroy 1 home every 11 seconds. In addition to the winds and the heat, an important factor in the rapid spread of the fire was that it started in an area that was at an interface between developed and undeveloped land. Many of the first dwellings to burn were surrounded by thick, dry vegetation. In addition, the nearby undeveloped land had even more dry brush along with several groves of non-native volatile eucalyptus trees. The same conditions contributed to ..the Berkeley 1923 fire.” http://en.wikipedia.org/wiki/Oakland_Hills_firestorm A major fire near Limantour Beach in Point Reyes National Seashore in October 1995 consumed 48 homes and scorched 12,000 acres (1/7th of the park.) Some say that Marin County, California (where I live) is a forest fire disaster waiting to happen…
