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Vol. 25, No. 3 Summer 2015
Summer 2015 GRASSLANDS | 6
An Extension Perspective on California Grassland Restoration
by Elise S. Gornish1
Grassland systems are some of the most economically, socially, and
environmentally important habitats in California. Unfortunately,
widespread development and massive degradation have eroded and
continue to erode the persistence and health of these systems (e.g.,
Cameron et al. 2014), making them one of the most endangered
ecosystems both within and outside of the state (Sampson and Knopf
1994, Peters and Noss 1995). As a result of grassland loss in
California, restoration of these systems is becoming a more critical
component of grassland conservation activities. Restoration in
California grasslands generally facilitates revegetation and soil
recovery by encouraging natural community reassembly processes
that might otherwise take decades to occur in the absence of
management (Beltran et al. 2014). This process includes extensive
weed control before, during, and for several years after planting
Estimates of rangeland ownership vary widely, depending on the
classification of grasslands in different habitat types, but generally,
from one-half to two-thirds of California’s grasslands characterized
as rangeland habitat are privately owned (L. Macaulay, University of
California, Berkeley, pers. comm.). Therefore, the onus of restoration
is increasingly falling on private landowners. However, despite the
variety of valuable benefits that grassland restoration can provide to
landowners, including forage for livestock, habitat for wildlife
including pollinators, enhanced infiltration, and enhanced nutrient
cycling, restoration activities on private lands are not sufficiently
widespread to adequately cope with habitat degradation. As a
member of UC Cooperative Extension, I have the opportunity to
interact with diverse stakeholders at workshops, field days, and
society conferences. At these events, I have conducted informal
surveys to understand the factors that drive landowner restoration
decision-making strategies. These factors can vary across landowner
types, but they appear to all be connected by a single theme:
uncertainty. And, until academic researchers and Cooperative
Extension staff can adequately address the uncertainty associated
with grassland restoration, the deployment of successful, widespread
restoration activities on private lands will remain relatively
Here, I outline some of the more convoluted aspects of restoration
that might hinder widespread adoption and suggest several ways that
these issues could be addressed in order to better serve the
informational needs of the private landowner.
Context Dependency
Restoration success is hugely context-dependent (Young et al. 2015).
Techniques that prove effective at a site during one year might not
demonstrate particular utility the next year. This variability is likely
due to differences in weather, which can be more important than
applied management for modifying plant communities (e.g., Swiecki
and Bernhardt 2008). Additionally, site-specific factors such as
topography, soil moisture, soil type, soil microbial biomass, land use
history, and micronutrient availability can directly and indirectly
mediate restoration outcomes. Because landscapes are
heterogeneous, successful restoration practices employed at one site
might not be efficacious at a nearby, seemingly similar site. Research
that attempts to understand mechanisms driving differences in
germination, growth, and survival is critical for developing broad
guidelines for grassland restoration that can accommodate site-
specific characteristics. This type of research, which merges plant
population biology with restoration ecology, is gaining more traction
at the level of universities and experimental stations (e.g., James et al.
2011). However, until this becomes a more common research
initiative, practitioners should be considerate of context dependency
and perhaps explore the use of trait-based approaches where
restoration candidates are identified based on their display of
particular traits that confer resilience to local site characteristics
(Funk et al. 2008).
Management Goals
Uncertainty is also associated with benefits that can be derived from
grassland restoration. Despite examples of ecosystem services that
might offset restoration costs in the short- and long-term,
landowners lack information needed to confidently predict
anticipated outcomes from restoration activities. Many studies have
identified ecosystem services that can be enhanced with restoration;
for example, effective restoration can arrest topsoil loss and rebuild
soil carbon (Lal 2006), which increases forage production.
Restoration and revegetation strategies can also markedly improve
wildlife habitat, providing more valuable grasslands for hunting and
recreation activities. Perhaps there needs to be improvement in the
communication of this information from researchers and
Cooperative Extension to landowners. This type of information can
be effectively transmitted during field days, through publications in
the popular press, and via a strong social media presence. Moreover,
formal studies that directly link reseeding activities to other
management goals, like forage production, are relatively uncommon.
However, this avenue of research will be useful for highlighting how
to accomplish multiple vegetation goals from single management
Monetary Feasibility
Finally, uncertainty in restoration outcomes makes it difficult to
assess whether management investment will pencil out financially
in subsequent seasons. Depending on factors such as seed mix, seed
source, and seed rarity, native grassland seed can be extremely
expensive, and coupled with extensive pre-treatment activities such
as weed management, site preparation, and drill rental, restoration
1Elise Gornish is a new Cooperative Extension Specialist in Restoration Ecology, UC Davis. Dr. Gornish focuses on restoration of grassland and arid
systems in both natural and working landscapes. She also conducts research and outreach on invasive annual grasses. The invasive species she most
loves to hate is the invasive winter annual grass medusa head (Elymus caput-medusae).
continued next page
7| GRASSLANDS Summer 2015
can cost upwards of $3,000/acre. This cost is simply untenable for
most private landowners. Avenues of less costly restoration and
revegetation practices have been investigated, including strip seeding
(Rayburn and Laca 2013), which can reduce seed quantities and
labor costs. Using revegetation-based approaches involving non-
local germplasm or non-native (desired, non-invasive) species in the
short-term can enhance long-term establishment by natives (e.g.,
Davies et al. 2015) and replenish soil nitrogen (SER International
2004). Using seed from regional sources in the early stages of a
revegetation project (D’Antonio and Meyerson 2002) can also
enhance invasive species control because non-local germplasm can
confer greater competitive response to newly invaded weeds (e.g.,
Davies et al. 2010, Herget et al. 2015). Costs for restoration or
revegetation activities on private land can sometimes be partially
offset by state programs, such as the California Department of Fish
and Wildlife Landowner Incentive Program (LIP), as well as through
associations with local groups, such as Habitat Conservation
Planning branches and the Center for Land-Based Learning’s
Student and Landowner Education and Watershed Stewardship
(SLEWS) program.
Despite these advances in the field, the cost of restoration can still be
prohibitive for most landowners. Research developments in the field
of horticulture could provide landowners with technologies to make
native plant propagation a successful enterprise without taking large
amounts of land out of production. Including regular cost/benefit
analyses in restoration experiments (e.g., Palmerlee and Young 2010)
is another way that researchers can add value to existing decision-
making tools that help managers develop more successful,
monetarily feasible restoration programs.
Several of the above suggestions involve creative approaches to
grassland restoration and revegetation to minimize costs and efforts
and make habitat improvements feasible. However, considering that
many acres of privately held grasslands in California are working
landscapes, I believe that realistic attempts to partner with private
landowners to restore functional plant communities will only be
successful when the needs and goals of all stakeholders are
considered. Ultimately, large-scale successful restoration of
grasslands on privately owned land will be possible through the
cultivation of networks among academia, Cooperative Extension,
agencies, non-profit organizations, and landowners and will rely on
bidirectional communication among these groups.
Beltran, R.S., N. Kreidler, D.H. Van Vuren, S.A. Morrison, E.S. Zavaleta, K.
Newton, B.R. Tershy, and D.A. Croll. 2014. “Passive recovery of vegetation
after herbivore eradication on Santa Cruz Island, California.Restoration
Ecology 22:790–797.
Cameron, D.R., J. Marty, and R.F. Holland. 2014. “Whither the rangeland?
Protection and conversion in California’s rangeland ecosystems. PLoS ONE
D’Antonio C.D., and L.A. Meyerson. 2002. “Exotic plant species as problems
and solutions in ecological restoration: A synthesis. Restoration Ecology
Davies, K.W, A.M. Nafus, and R.L. Sheley. 2010. “Non-native competitive
perennial grass impedes the spread of an invasive annual grass.Biological
Invasions 12:3187–3194.
Davies, K.W., C.S. Boyd, D.D. Johnson, A.M. Nafus, and M.D. Madsen. 2015.
“Success of seeded native compared with introduced perennial vegetation
for revegetating medusahead-invaded sagebrush rangeland.Rangeland
Ecology & Management 68:224–230.
Funk, J.L., E.E. Cleland, K.N. Suding, and E.S. Zavaleta. 2008. “Restoration
through reassembly: Plant traits and invasion resistance.Trends in Ecology
and Evolution 23:695–703.
Herget, M.E., K.M. Hufford, D.L. Mummer, B.A. Mealor, and L.N.
Shreading. 2015. “Effects of competition with Bromus tectorum on early
establishment of Poa secunda accessions: Can seed source impact
restoration success? Restoration Ecology 23:277–283.
Extension Perspective continued
continued next page
Summer 2015 GRASSLANDS | 8
Californias New Front Yard:
Creating a Low-Water Landscape
Now Registering for Fall 2015 Locations
CNGA is taking this popular workshop series on the road beginning
Fall 2015. Registration is open for Fairfield and Sacramento workshops.
Spring 2016 workshops will be offered in Merced and Santa Cruz.
Fairfield: Thursday, October 1, 8 a.m.–3 p.m.
Willow Hall, Fairfield Community Center, 1000 Kentucky Street
Sacramento: Thursday, October 29, 8 a.m.–3 p.m.
Coloma Community Center, 4623 T Street
Presentations in the morning will be followed by afternoon
demonstrations and hands‐on activities that will show you
how to carry out your project from beginning to end.
$25/CNGA Members | $30/Non-Members. Included in your fees are
morning refreshments, lunch, and course materials.
Come to one of these workshops to find out more about landscape
alternatives, including the use of native grasses, and forbs in the
drought-tolerant landscape. Workshops will include the latest research
and practices on design, installation, and maintenance of a low-water
landscape, as well as proper plant selection, lawn removal methods,
irrigation, and long-term care.
To register visit or call 530.902.6009.
Extension Perspective continued
James, J.J., T.J. Svecar, and M.J. Rinella. 2011. “Demographic processes limiting seedling recruitment
in arid grassland restoration.Journal of Applied Ecology 48:961–969.
Lal, R. 2006. “Enhancing crop yields in developing countries through restoration of soil organic
carbon pool in agricultural lands.Land Degradation and Development 12:197–209.
Palmerlee, A.P., and T.P. Young. 2010. “Direct seeding is more cost effective than container stock
across ten woody species in California. Native Plants 11:89–102.
Peters, R.L., and R.F. Noss. 1995. “America’s endangered ecosystems.Defenders 70:16–27.
Rayburn, A., and E.A. Laca. 2013. “Strip-seeding for grassland restoration: Past successes and future
potential. Ecological Restoration 31:147–153.
Sampson, F.B., and F.L. Knopf. 1994. “Prairie conservation in North America.BioScience 44:418–
SER International (Society for Ecological Restoration International Science & Policy Working Group).
2004. The SER International Primer on Ecological Restoration. Tucson, AZ: Society for Ecological
Restoration International.
Swiecki, T.J., and E. Bernhardt. 2008. “Effects of
Grazing on Upland Vegetation at Jepson Prairie
Preserve, Solano County, CA.” Final Report.
Vacaville, CA: Phytosphere Research.
Young, T.P., E.P. Zefferman, K.J. Vaughn, and S.
Fick. 2015. “Initial success of native grasses is
contingent on multiple interactions among exotic
grass competition, temporal priority, rainfall, and
site effects.AoB PLANTS 7:plu081.
ResearchGate has not been able to resolve any citations for this publication.
Full-text available
When landscapes are heavily impacted by biological invasion, local populations of native plant species may no longer be adapted to altered environmental conditions. In these cases, it is useful to investigate alternative sources of germplasm, such as cultivated varieties, for planting at restoration sites. This study compared cultivated and wild (local) varieties of the native perennial bunchgrass, Poa secunda J. Presl, grown with and without the exotic, invasive Bromus tectorum L. in a greenhouse setting. While P. secunda cultivars emerged and grew more rapidly than wild seed sources, this advantage declined in the presence of B. tectorum and cultivated germplasm did not outperform wild accessions in the presence of an invasive species. Given the novel genetic background of cultivars and their potential to alter patterns of dominance in native plant communities, we recommend the use of local or regional wild seed sources when possible to conserve regional patterns of genetic diversity and adaptation. Use of multiple seed sources may increase the potential for capturing vigorous genotypes in the restoration seed mix. In cases where sites are heavily impacted by exotic, invasive species, other control measures will be necessary to improve establishment of native species in grassland restoration programs.
Full-text available
Ecological communities are increasingly being recognized as the products of contemporary drivers and historical legacies that are both biotic and abiotic. In an attempt to unravel multiple layers of ecological contingency, we manipulated a) competition with exotic annual grasses, b) the timing of this competition (temporal priority in arrival/seeding times), and c) watering (simulated rainfall) in a restoration-style planting of native perennial grasses. In addition, we replicated this experiment simultaneously at three sites in north-central California. Native perennial grasses had 73-99% less cover when planted with exotic annuals than when planted alone, but this reduction was greatly ameliorated by planting the natives two weeks prior to the exotics. In a drought year, irrigation significantly reduced benefits of early planting so that these benefits resembled those observed in a non-drought year. There were significant differences across the three sites (site effects and interactions) in a) overall native cover, b) response of natives to competition, c) the strength of the temporal priority effect, and d) the degree to which supplemental watering reduced priority effects. These results reveal the strong multi-layered contingency that underlies even relatively simple communities. Published by Oxford University Press on behalf of the Annals of Botany Company.
Full-text available
Understanding how insular ecosystems recover or are restructured after the eradication of an invasive species is crucial in evaluating conservation success and prioritizing island conservation efforts. Globally, herbivores have been removed from 762 islands, most with limited active restoration actions following eradication. Few studies have documented the effects of invasive herbivore removal after multiple decades of passive recovery. Here we evaluate recovery of vegetation on Santa Cruz Island, California, after the removal of feral sheep (Ovis aries) in 1984. We repeat a study conducted in 1980, and examine vegetation changes 28 years after the eradication. Before eradication, grazed areas were characterized by reduced plant cover, high exposure of bare ground, and erosion. After 28 years of passive recovery, transect data showed a 23% increase in woody overstory, whereas analysis of photographs from landscapes photographed pre- and post-eradication showed a 26% increase in woody vegetation. Whole island vegetation maps similarly showed a transition from grass/bare ground (74.3% of cover) to woody plants (77.2% of cover), indicating the transition away from predominantly exotic annual grassland toward a community similar to the overstory of coastal scrubland but with an understory dominated by non-native annual grasses. We estimate that replacement of grasses/bare ground by native woody vegetation has led to 70 and 17% increases in the stored carbon and nitrogen pools on the island, respectively. Our results demonstrate that these island ecosystems can experience significant recovery of native floral communities without intensive post-eradication restoration, and results of recovery may take decades to be realized.
Full-text available
Land use change in rangeland ecosystems is pervasive throughout the western United States with widespread ecological, social and economic implications. In California, rangeland habitats have high biodiversity value, provide significant habitat connectivity and form the foundation for a number of ecosystem services. To comprehensively assess the conservation status of these habitats, we analyzed the extent and drivers of habitat loss and the degree of protection against future loss across a 13.5 M ha study area in California. We analyzed rangeland conversion between 1984 and 2008 using time series GIS data and classified resulting land uses with aerial imagery. In total, over 195,000 hectares of rangeland habitats were converted during this period. The majority of conversions were to residential and associated commercial development (49% of the area converted), but agricultural intensification was surprisingly extensive and diverse (40% across six categories). Voluntary enrollment in an agricultural tax incentive program provided widespread protection from residential and commercial conversions across 37% of the remaining rangeland habitat extent (7.5 M ha), though this program did not protect rangeland from conversion to more intensive agricultural uses. Additionally, 24% of the remaining rangeland was protected by private conservation organizations or public agencies through land or easement ownership while 38% had no protection status at all. By developing a spatial method to analyze the drivers of loss and patterns of protection, this study demonstrates a novel approach to prioritize conservation strategies and implementation locations to avert habitat conversion. We propose that this approach can be used in other ecosystem types, and can serve as a regional conservation baseline assessment to focus strategies to effect widespread, cost-effective conservation solutions.
Full-text available
The planting of native woody plants is a cornerstone of many habitat restoration projects. Current techniques for revegetating disturbed or reclaimed plant communities often consist primarily of planting trees and shrubs from container stock, which can be costly to buy or produce, time-consuming to plant (an additional cost), and logistically difficult for large-scale restoration projects. We tested whether direct seeding woody species was more cost effective than planting container stock. During fall 2004, we planted 3 sites encompassing the ecotone of foothill riparian and woodland habitats in northern California with 10 native species of woody plants, both as container stock and direct seed. Data on survival were collected over a 2-y period. Across species, the planting success of direct-seeded plants, but not container plants, increased significantly with increasing mean seed size. Although seeds generally had lower individual planting success than did container stock, this was always offset by the higher costs of purchasing and planting container stock. Direct seeding was up to 29 times more cost effective than planting container stock when considering base costs (not including fixed costs of tubes, irrigation, and herbicide). Including these additional costs reduced the cost advantage, but direct seeding remained more cost effective per surviving plant across all species, and especially so for large-seeded species.
Full-text available
Exotic species have become increasingly significant management problems in parks and reserves and fre-quently complicate restoration projects. At the same time there may be circumstances in which their re-moval may have unforeseen negative consequences or their use in restoration is desirable. We review the types of effects exotic species may have that are im-portant during restoration and suggest research that could increase our ability to set realistic management goals. Their control and use may be controversial; therefore we advocate consideration of exotic species in the greater context of community structure and suc-cession and emphasize areas where ecological re-search could bring insight to management dilemmas surrounding exotic species and restoration. For exam-ple, an understanding of the potential transience of exotics in a site and the role particular exotics might play in changing processes that influence the course of succession is essential to setting removal priorities and realistic management goals. Likewise, a greater understanding of the ecological role of introduced species might help to reduce controversy surrounding their purposeful use in restoration. Here we link gen-eralizations emerging from the invasion ecology liter-ature with practical restoration concerns, including circumstances when it is practical to use exotic species in restoration.
Millions of hectares of Wyoming big sagebrush (Artemisia tridentata Nutt. subsp. wyomingensis Beetle &Young) rangeland have been invaded by medusahead (Taeniatherum caput-medusae [L.] Nevski), an exotic annual grass that degrades wildlife habitat, reduces forage production, and decreases biodiversity. Revegetation of medusahead-invaded sagebrush plant communities is necessary to restore ecosystem services. Disagreement, however, exists over whether to seed native or introduced perennial species to revegetate communities after controlling medusahead. Though native species generally do not establish as well as introduced species, interference from co-seeded introduced species has often been attributed to the limited success of natives. The potential for seeding natives to revegetate communities after medusahead control is relatively unknown because they have been largely co-seeded with introduced species. We compared the results of seeding native and introduced perennial species after controlling medusahead with prescribed burning followed with an imazapic herbicide application at five sites. Perennial bunchgrass cover and density were 5- and 10-fold greater in areas seeded with introduced compared with native species 3 years post seeding. Furthermore, exotic annual grass cover and density were less in areas seeded with introduced compared with native species. Seeded introduced and native shrubs largely failed to establish. High perennial bunchgrass density (15 individuals · m- 2) in areas seeded with introduced species in the third year post seeding suggests that the succession trajectory of these communities has shifted to becoming perennial dominated. Average perennial bunchgrass density of 1.5 individuals · m- 2 with seeding native species will likely not limit medusahead and appears to already be converting back to exotic annual grass-dominated communities. These results suggest that seeding introduced compared with native species after medusahead control will likely be more successful. Our results also imply that if natives are selected to seed after medusahead control, additional resources may be necessary to recontrol medusahead and repeatedly sow native species.
The health and future of the earth's ecological systems (Dailey and Ehrlich 1992), their link to the well being of communities and nations (Raven 19901, and the ever-increasing rate of loss of species, communities, and ecological systems (Myers 1993) are among issues drawing biological diversity into the mainstream of conservation worldwide. Yet. in North America, there is no single, established priority in the conservation of biological diversity. In recent years, a great deal of attention has been paid to the problem of tropical and temperate deforestation in part because of profound consequences to the conservation of biological diversity (Harris 1984, Whitmore and Saver 1992.). Despite a broad consensus supporting the conservation of biological diversity (CEQ 1991), native prairie is largely neglected in this effort. This article suggests why native prairie in North America should be among the priorities in conservation of biological diversity. We further describe the extent and cause of the decline of North American prairie and offer recommendations for prairie conservation.
Perennial grassland restoration has become an important worldwide conservation objective due to ongoing reductions in biodiversity, ecosystem services, habitat, and landscape aesthetics. However, the success of grassland restoration strategies remains limited by many factors, including high cost. We present strip-seeding as a novel grassland restoration tool with the potential to be both ecologically and economically viable for a wide range of site conditions and management objectives. Strip-seeding refers to the application of seed in linear swaths to some fraction of total field area, as opposed to seeding uniformly across the entire field. Strip-seeding allows concentration of planting effort on a proportion of total field area to increase the probability of success in establishing desirable species while also decreasing seeding costs. Once established, desirable species should disperse and colonize unseeded areas over time without the need for further direct seeding. We reviewed existing literature on strip-seeding and related methods of spatially-patterned seeding. We discuss the potential advantages and underlying mechanisms of strip-seeding as a restoration method, including increased establishment, spread of seeded species into unseeded areas, and reduced restoration cost. We then propose four future research directions related to 1) designing strip configurations to match site conditions, 2) weed control in unseeded strips, 3) strip-seeding as a tool for grassland diversification, and 4) the scaling of restoration effects on ecosystem services. Strip-seeding has the potential to become an economically viable method for perennial grassland restoration and its adoption will be facilitated by future research that addresses these gaps in knowledge.