RESTORING RIVERINE RESILIENCE: Using historical ecology to design for eco‐geomorphic complexity on an intermittent river
Erin Beller Resilient Landscapes Program San Francisco Estuary Institute Ecological Society of America Minneapolis, Minnesota ~ August 7, 2013
What do we mean by resilience? A system’s ability to: absorb disturbances while maintaining fundamental structure and functions (Carpenter et al. 2001, Gunderson and Holling 2001)
cope with novel situations without losing options for the future (Adger 2003)
What do we mean by resilience? range of tolerance (ca. 1800) range of tolerance (ca. 2000)
Disturbance, e.g. flood drought fire climatic change anthropogenic change
What do we mean by resilience? range of tolerance (ca. 1800) range of tolerance (ca. 2000)
Disturbance, e.g. flood drought fire climatic change anthropogenic change
Resilience is key to ecosystem restoration. (But what does that actually mean?) • Complexity • Diversity • Heterogeneity • Connectivity • Refugia • Scale • Functionality • Size • Persistence
We can use history to understand what resilience means for a specific ecosystem. Study goals: • What was the historical (early 1800s) eco‐geomorphology of the Santa Clara River? • How was it resilient to extreme climatic events? •
How can we enhance/restore resilience in the future?
Santa Clara River riparian forest ca. 1850
The Cienega
East Grove
West Grove ca. 1840 “cottonwood and willow swamp” (1853) “bottom land covered with willows” (1874) “poplars and willows line its marshy shores” (1887)
ca. 1840 “a grove of cottonwoods…nearer to a forest than anything I have yet seen here” (1861) “poplars, willows, and stunted live‐oaks, partly open and partly crowded with dense shrubbery” (1887)
“It is an enigma to me why Mr. Cook should have chosen this desert for his home, when he is right in sight of a place like Bardsdale.” (1889)
Santa Clara River dry season flow ca. 1850
The Cienega
East Grove “stopped flowing” “large flow of water” (August 1769) (August 1769)
“runs permanently” (summer 1887)
West Grove
“dry in summer” (summer 1887) “water flowing” (Sept 1868)
perennial intermittent
Santa Clara River riparian forest ca. 1850 and 2007
The Cienega
East Grove
West Grove
• Historical nodes match contemporary nodes • Decrease in area; fragmentation
November 2008 Watercress farms in former floodplain marsh
49% loss
v v 1855
2100 m corridor
2005
300 m corridor rendered by Jen Natali
Resilience is key to ecosystem restoration. (But what does that actually mean here?) • Complexity • Diversity • Heterogeneity • Connectivity • Refugia • Scale • Functionality • Size • Persistence
Topographic complexity + high lateral connectivity • Flood peak attenuation • Plan form/river corridor stability • Riparian forest persistence
Resilience is key to ecosystem restoration. (But what does that actually mean here?) • Complexity • Diversity • Heterogeneity • Connectivity • Refugia • Scale • Functionality • Size • Persistence
Topographic complexity + high lateral connectivity • Flood peak attenuation • Plan form/river corridor stability • Riparian forest persistence Heterogeneous flow + low longitudinal connectivity • High regional biodiversity • “Diverse portfolio” of species adapted to a range of conditions
Resilience is key to ecosystem restoration. (But what does that actually mean here?) • Complexity • Diversity • Heterogeneity • Connectivity • Refugia • Scale
Topographic complexity + high lateral connectivity • Flood peak attenuation • Plan form/river corridor stability • Riparian forest persistence Heterogeneous flow + low longitudinal connectivity • High regional biodiversity • “Diverse portfolio” of species adapted to a range of conditions
• Functionality • Size • Persistence
Large, persistent riparian forested wetlands • High‐flow and drought refugia for wildlife • Diverse set of age classes for riparian species
1843 2007
1924
March 2008 Passive restoration of willow forest on former ag land, after 2005 floods
range of tolerance (ca. 1800) range of tolerance (ca. 2000)
• • • • •
Removal of floodplains from river corridor Fragmentation and loss of riparian forest Loss of refugia in perennial reaches Water diversions, pumping Invasive species (e.g., Arundo)
range of tolerance (ca. 1800) range of tolerance (ca. 2000)
• • •
Reconnect river to floodplain Keep wet reaches wet and dry reaches dry Restore riparian forest around existing nodes
The future will be different than the present and the past.
Historical ecology can illuminate how to make landscapes more resilient in the future.
THANKS TO Co‐authors Peter Downs, University of Plymouth Robin Grossinger and Micha Salomon, SFEI Bruce Orr, Stillwater Sciences Additional Team Members Eric Stein, SCCWRP Shawna Dark, CSU Northridge Travis Longcore, UC Los Angeles Gretchen Coffman, University of San Francisco Funder California State Coastal Conservancy
[email protected] www.sfei.org/HE
