River Partners’ Long-Term Monitoring Program
By Jessica Hammond, Restoration Ecologist
In the September 2010 issue of the River Partners’ Journal, the article entitled Looking Back: River Partners initiates the long term monitoring project to evaluate restoration sites announced the start of our Long- Term Monitoring Program. The article described how biological monitoring of plant performance during the three-year project period helps to guide our adaptive management strategy, and provides data that allows us to continually advance the science of horticultural restoration. While biological monitoring is an important component of all restoration projects River Partners undertakes, monitoring beyond the project period (typically three years) is frequently not possible due to funding limitations.
Long-term monitoring allows us to look back at restoration sites decades after intensive management practices cease and provides insight to our understanding of how these plant communities change and evolve through time. This type of information gives us a detailed understanding of how plants respond to ecological variables and provides us with an understanding of how ecologically resilient plantings are in response to events such as floods, fire, and climate change. This type of information is critical not only for understanding how restoration projects will meet the needs of wildlife over a long time scale, but also to ensure that plantings will not interfere with flood flows in the designated floodway. With this in mind, River Partners, with support from our partners at the Central Valley Joint Venture (CVJV), initiated the Long-Term Monitoring Program to re-visit some of the earliest riparian restoration plantings. The goal of this initial pilot effort was to evaluate the horticultural and ecological performance of plantings through time.
In 2009, River Partners biologists began collecting data at some of the oldest riparian restoration plantings on the Sacramento River. Data collection involved visiting restoration plantings that were planted 8-17 years ago and collecting careful measurements of trees and shrubs to accurately document the structural development of some of the oldest restoration plantings on the Sacramento River. The ultimate goal of this initial pilot study was to compare the data that we collected in the field to the historical planting records of the very same sites. This process enabled us to answer questions about individual species performance, structural changes in the developing vegetation of a restoration project through time, and changes in community composition.
While collecting data our biology staff noticed something exciting: within these sites we were finding trees of varying ages- -an indication that forest succession was beginning to take place. Young saplings were present at many of the study sites, sprouting opportunistically where light was able to break through the canopy. Tiny seedlings of native species were found breaking through the thick duff layer of fallen cottonwood leaves from previous years. While it was clear from our observation that forest succession was underway at many of these sites, it was the meticulous collection of data that allows us to best describe the processes that are underway.
Our results indicated that species such as box elder (Acer negundo) and coyote brush (Baccharis pilularis), two common riparian species whose seeds are dispersed by both wind and water, readily recruited at many of our study sites. Additionally, we found many native species of vines had established at these sites that were not planted as part of the restoration, including wild grape (Vitis californica), clematis (Clematis ligusticofolia), Dutchman’s pipevine (Aristilochia californica), and poison oak (Toxicodendron diversilobum). We know that these species were not planted at these sites by looking at the historical planting records, which indicates that seeds were therefore carried into plantings by wind, water, or animal movement. This increase in native species diversity is important to our understanding of how restoration habitat matures and evolves through time. The establishment of native vine species can increase the structural diversity of habitat and provide additional food sources to many wildlife species, including neotropical migratory birds and terrestrial wildlife.
Understanding how restoration plantings change through time arms us with the information necessary to make long term predictions about the suitability of these large-scale projects for wildlife for years and decades to come. To share our results with the rest of the restoration community, River Partners is pleased to report the submission of the manuscript for the pilot study of the Long-Term Monitoring Program has been submitted for review to the scientific journal Restoration Ecology and will post a copy of this manuscript on our website upon publication.
In addition to this initial pilot study examining horticultural performance of restoration projects, River Partners initiated an avian monitoring component to the Long-Term Monitoring program in the spring of 2010. The avian monitoring component of this project aims to correlate specific restoration design elements with avian diversity data to help inform future restoration design and ensure that projects are meeting their longterm objectives. Avian monitoring has been conducted for two years, and River Partners will begin to analyze these data in the summer of 2011.