FRC Funds New Z-Grass Research on Fall River

New Z-Grass Research Funded By FRC In 2013

FRC Funds Chico State to Research Z-Grass Restoration Strategies in Fall River

FRC is pleased to announce a new partnership in the spring of 2013 with the Chico State Department of Biological Sciences. Beginning this month, Dr. Kristina Schierenbeck will lead a team of researchers to explore new strategies for restoring Zannicheliia palustris (Z-grass) throughout the Fall River. The team will experiment with new re-vegetation methodologies and also assess the benefits that Z-grass provides for bugs, periphyton, and fish.

Read below for a full description of the research plan.

Introduction

Zannichellia palustris is an aquatic, herbaceous, flowering plant native to North America.  It is common where it occurs in fresh to brackish waters and can form large colonies.  Zannichellia palustris has a significant positive effect on species diversity and species interactions providing fish food via invertebrate habitat and refuge from predation, particularly when it is present throughout the water column.  The shallowly rooted Z. palustris has been documented to occur up to depths of 16 feet and in the Fall River occurs at water depths of 6 inches to 8-12 feet.

Although once present throughout the Fall River, Shasta County, California, it has virtually disappeared from some areas due to extensive sediment accumulation that began in 1983 (Spencer and Ksander 2002).  Sedimentation and the subsequent decline of Z. palustris are thought to be contributing factors to the decline of native trout populations in the Fall River.   Although viable seed banks of Z. palustris are thought to exist for many years, burial under greater than 2 cm of sediment will inhibit germination (Spencer and Ksander 2002).

There are many examples of channel modification and engineering to encourage native plant growth and restore flow regimes; however actual in-stream planting has not been attempted while maintaining water flows.  The only successful programs where aquatic plant restoration has been implemented are for eelgrass (Zostera marina) in estuarine systems (Thom et al. 2005).  Methods for eelgrass restoration include the manual planting of greenhouse grown plant shoots and broadcast seeding for several consecutive years (Pickerell et al. 2005).  Data on increasing fish populations with aquatic restoration is limited; however, it is clear that habitat improvements may take as long as a decade to result in a significant increase in fish abundance.

Questions

Questions to be addressed:  1. What are the most successful and cost effective methods of Z. palustris re-vegetation in the Fall River?  2.  Following the establishment of Z. palustris, are there positive effects in fish habitat as measured by invertebrate and periphyton activity?

Methods

In-stream restoration of aquatic vegetation has not been attempted experimentally, thus some preliminary experimentation will be required to establish the most efficacious methods for plant establishment.  Seed germination for Z. palustris has been established as optimal at temperatures of 25-30^oC, which occur in the Fall River from mid-June through mid-July.  At temperatures from 5-15^oC, 25-45% of seeds will germinate although with longer times to germination.  Experimentation in the Carruthers lab at USDA/ARS indicates that seeds will germinate in light temperatures equivalent to those found at about 9 feet at mid-day in January.  Well- hydrated Z. palustris sink quickly, thus reestablish may be possible via seeding.  Perturbation of the sediment has been demonstrated to increase Z. palustris recruitment and thus will be included as a treatment (Hidding et al. 2010).  Experimentation with small plants will determine if the shallowly rooted Z. palustris requires anchoring.

The evaluation of different seeding and planting techniques will require technical trials to begin in May 2013 with the following treatments:  1. Control (no treatment), 2. Sediment disturbance, 3. Direct seeding without anchoring to the river bottom, 4. Planting young plants without anchoring to the river bottom, 5. Direct seeding with anchoring via a biodegradable fabric anchored with stakes, and 6. Planting young plants with anchored fabric.   If any of these treatments are untenable or need modification, adjustments to the experimental treatments will be necessary.  About 25,000 seeds have been collected and are available for experimentation.  Each of the six treatments will be replicated three times at different locations along the river between the headwaters of the Fall River and the Spring Creek Bridge.  At each site, each treatment will be replicated five times for a total of 90 plots.  Each experimental plot will be 1.5 m² with 30 plants or seeds per site.  Planting and seeding density may need adjustment in the field.

Monthly sampling of all plots will include the following measurements:  stem/plant frequency, mortality, and percent cover.   Plots will be sampled with a sinkable plot, photographed with an underwater camera and the images evaluated in the lab.  Preliminary work indicates that this is an effective sampling method.  At quarterly intervals, leaf samples will be collected and quantified for periphyton colonization and composition.  Invertebrate composition in the plots will also be sampled quarterly with nets without damage to the plants.   One year after planting, five plants from each plot will be harvested, dried and measured for above and below ground biomass.  Data will be analyzed with an Analysis of Variance for differences among treatments and ordination methods will be used to assess environmental parameters associated with planting.

Schedule

Literature Cited

Hibbing, B., B.A. Nolet, T. deBoer, P.P. deVries, and M. Klassen.  2010.  Above- and below-ground vertebrate herbivory may each favor a different subordinate species in an aquatic plant community.  Oecologia 162:199-208.

Pickerell, C.H., S. Schott, and S. Wyllie-Echeverria.  2005.  Buoy-deployed seeding:

Demonstration of a new eelgrass (Zostera marina L.) planting method.  Ecological Engineering 1725:127-136.

Spencer, D.F. and G.G. Ksander.  2002.  Sedimentation disrupts natural regeneration of

Zannichellia palustris in Fall River, California.  Aquatic Botany 73:137–147

Thom, R.M., G. Williams, A. Borde, J. Southard, S. Sargeant, D. Woodruff, J.C. Laufle, and S.

Glasoe. 2005. Adaptively Addressing Uncertainty in Estuarine and near Coastal Restoration

Projects.  Journal of Coastal Research: 94-108.