Source: UNIVERSITY OF CALIFORNIA, DAVIS submitted to
EXOTIC AND NATIVE SPECIES IN CALIFORNIA GRASSLAND RESTORATION
Sponsoring Institution
National Institute of Food and Agriculture
Project Status
TERMINATED
Funding Source
HATCH
Reporting Frequency
Annual
Accession No.
0183392
Grant No.
(N/A)
Project No.
CA-D-PLS-6599-H
Proposal No.
(N/A)
Multistate No.
(N/A)
Program Code
(N/A)
Project Start Date
Oct 1, 2008
Project End Date
Sep 30, 2013
Grant Year
(N/A)
Project Director
Young, T.
Recipient Organization
UNIVERSITY OF CALIFORNIA, DAVIS
410 MRAK HALL
DAVIS,CA 95616-8671
Performing Department
Plant Sciences
Non Technical Summary
The repair of California's natural and human-dominated ecosystems is increasingly a major goal of land managers, but until recently these efforts have been carried out with only rudimentary understanding of restoration goals and how best to achieve them. The University of California has been on the forefront of restoration research, and in particular applying the techniques, expertise, and multidisciplinary approaches of agricultural science to the recovery of these damaged ecosystems. My lab will continue to carry out applied research in ecological restoration, seeking to both help solve the practical problems faced by practicing restorationists, and to address the underlying concepts and principles of restoration. We use controlled experiments and descriptive data to analysis various aspects of restoration. We communicate our results in publications and through personal contacts with stakeholders, which has led to productive changes in the way that restorationists do their work. We are also beginning a collaborative research, outreach, and high school education project on rangeland restoration with Audubon California and the Center for Land-based Learning.
Animal Health Component
(N/A)
Research Effort Categories
Basic
(N/A)
Applied
(N/A)
Developmental
(N/A)
Classification

Knowledge Area (KA)Subject of Investigation (SOI)Field of Science (FOS)Percent
1210799107070%
1220699107010%
1220799107010%
1360799107010%
Knowledge Area
122 - Management and Control of Forest and Range Fires; 136 - Conservation of Biological Diversity; 121 - Management of Range Resources;

Subject Of Investigation
0699 - Trees, forests, and forest products, general; 0799 - Rangelands and grasslands, general;

Field Of Science
1070 - Ecology;
Goals / Objectives
The repair of California's natural and anthropogenic ecosystems is increasingly a major goal of land managers, but until recently these efforts have been carried out with only rudimentary understanding of restoration goals and how best to achieve them. The University of California has been on the forefront of restoration research, and in particular applying the techniques, expertise, and multidisciplinary approaches of agricultural science to the recovery of these damaged ecosystems. My lab will continue to carry out applied research in ecological restoration, seeking to both help solve the practical problems faced by practicing restorationists, and to address the underlying concepts and principles of restoration. In particular, our current research objectives are: 1. Quantify the environmental correlates of rangeland restoration success in California grassland and woodland. 2. Examine the cost-effectiveness of invasive control and native plant establishment in grasslands and woodlands, including seeding rates for over-seeding forbs into established native grass stands. 3. Test the magnitude of priority effects and year effects in the assembly of restored rangelands. 4. Examine the physiological, life history, and competitive differences between the annual and perennials grasses from both California and the Mediterranean, with an aim to developing more effective restoration techniques. 5. Extend our work to examine the effects of management and restoration of grasslands and woodlands in the developing world. Our expected outputs will be peer-reviewed publications and formal and informal reports and recommendation to restoration practitioners. We will continue to publish our research in the primary restoration and rangeland practitioner journals (Ecological Restoration and Restoration Ecology, Rangeland Ecology and Management) and in ecological journals (Ecology, Oecologia, Oikos, Journal of Ecology). We will also continue to make presentations at meetings directed toward "end-users", including the annual meetings of the California Native Grassland Association, the Society for Ecological Restoration, The Society for Conservation Biology, and the Laikipia Wildlife Forum.
Project Methods
At a variety of rangeland and woodland restoration sites and research restoration sites, our monitoring will include the assessment of local sites parameters and rainfall patterns. Parameters include land use (stocking rates), elevation, slope, aspect, soil type, seeding rate, total winter rainfall, onset of winter rains, and midwinter droughts. These will be covariates in statistical analyses of restoration success. We will carry out long-term monitoring of these sites, measuring cover (pin frame and biomass harvesting) by native and exotic species across soils types and topographic positions. A variety of field trails have been established at these sites. As the length of these trials increases, so does their value in elucidating promising vegetation management techniques. We will carry out detailed surveys of these plots, including measurement of percent cover (using a pin frame) and the density, survivorship, and growth of native and exotic species. At all our restoration and research sites, we will quantify both materials costs and labor costs for each phase of restoration projects. In sites with multiple planting schemes (different planting rates, different plant materials, different amendments) we will compare the success of the restoration plantings with the costs of those plantings (c.f. Palmerlee 2007). We will also examining the (cost) effectiveness of different seeding rates (1/2, full x2, x4 of recommended) for over-seeding native forbs into restored grassland sites. Species-specific density, cover, and reproduction will be measured in all sites. These results in particular will be communicated directly with practitioners, (Already, we have convinced several practitioners to use more direct seeding, and less container stock, based on our previous research.) We will be testing both priority effects with both spatial and temporal experiments. In the temporal experiments, we are planting different guilds of plants (native grasses, native forbs, invasive annuals with one-year temporal advantages in replicated 1.5 x 1.5 m plots in multiple sties in northern California. Some of these sites are active rangelands undergoing grassland restoration. To measure years effects, we are repeating these priority experiments each year for at least five years. In the spatial priority experiments, we will be planting polycultures (seed mixes) as well as a series of monocultures at different spatial scales, using restoration species mixes of more and less aggressive grasses and forbs. All plots will be monitored for at least five years. In collaboration with Robert Save of IRTA (Barcelona), we are quantifying various ecophysiological parameters (root hydraulic resistance, cuticular transpiration rates, relative water content and turgor loss point, specific leaf weight, and leaf perimeter/area ratio). We will also measure growth and reproductive rates, and responsiveness to summer rain. The three guild will be compared not only with ANOVAs, but also with discriminant analyses. We hypothesize that in many ways, California perennial; grasses are intermediate between Mediterranean annual and perennial.

Progress 10/01/08 to 09/30/13

Outputs
Target Audience: Restoration practitioners (including agencies and NGOs); rangeland managers; graduate and undergraduate students Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided? Multiple graduate students and undergraduate students were involved in this project. All participants got experience in research design and implementation. The undergraduate students were involved in seed collections and weighing (including training in species identifications). The graduate students were involved as partners in the details of plot layout, seeding, watering, and weed control, contributing key insights that were incorporated into the research design. How have the results been disseminated to communities of interest? This research is published in major peer-reviewed journals (see below). My lab and I also have made multiple presentations at the annual meetings for the California Native Grasslands Society, Society for Ecological Restoration, the Ecological Society of America, and the Northern California Botanists. The audiences of the first two included large proportions of restoration practitioners. We have also given research presentations at the University of Wyoming, University of Montana, Colorado State University, University of California at Davis, and Utah State University. What do you plan to do during the next reporting period to accomplish the goals? Nothing Reported

Impacts
What was accomplished under these goals? We have published 35 peer-reviewed papers relating to this project over the past five years, about evenly split between our work on restoration in California rangelands/grasslands and our work in a similar savanna ecosystem in Africa. Recent outcomes/impacts of our work have been: 1) The demonstration that California native perennial grasses behave more like annuals than do Mediterranean perennial grasses, which may help explain the success of invasive annuals into California’s rangeland ecosystems. 2) Demonstration of multiple positive interactions between livestock management and biodiversity in Africa, which mitigate their negative effects (which we also document). 3) The demonstration that direct seeding is often more cost-effective than using container stock. 4) Creation of a restoration prescription (now in use) for repairing degraded rangelands in Kenya. 5) The demonstration that planting spatially heterogeneous patches of species can increase the resultant species diversity in restored grasslands, by creating temporal priority for subordinate species. 6) Demonstration of multiple positive and negative interactions between livestock management and biodiversity in Africa. 7) Graduate students and a post-doc in our lab created user manuals for rangeland monitoring in Africa. 8) I also handle numerous telephone and email queries each year concerning ecological restoration, and manage the "restecol" listserv, which is a local and regional clearinghouse for restoration meetings, jobs, and volunteer and internship opportunities to over 200 subscribers. 9) Several of the graduate students in my lab have been active every year as mentors for the SLEWS program that brings (often disadvantaged) high school students to local farms and ranches to assist in restoration and land management projects.

Publications

  • Type: Journal Articles Status: Published Year Published: 2013 Citation: Porensky, L.M. & T.P. Young. 2013. Edge interactions in fragmented and patchy landscapes. Conservation Biology 27:509-519.
  • Type: Journal Articles Status: Published Year Published: 2013 Citation: Porensky, L.M., S.F. Bucher, K.E. Veblen, A.C. Treydte, and T.P. Young. 2013. Megaherbivores and cattle alter edge effects around ecosystem hotspots in an African savanna. Journal of Arid Environments 96:55-63.
  • Type: Journal Articles Status: Published Year Published: 2013 Citation: Porensky, L.M., S.E. Wittman, C. Riginos & T.P. Young. 2013. Herbivory and drought interact to enhance diversity and spatial patterning in a savanna understory. Oecologia 173:591-602.
  • Type: Journal Articles Status: Published Year Published: 2013 Citation: Kirigia, A., J.T. Njoka, P.I.D Kinyua & T.P. Young. 2013. Characterizations of livestock manure marketing chain and the annual income contribution of manure trade in Mukogodo, Laikipia, Kenya. African Journal of Agricultural Research 8: 5864-5871.
  • Type: Journal Articles Status: Published Year Published: 2013 Citation: Wilkerson, M.L., L.M. Roche, & T.P. Young. 2013. Indirect effects of domestic and wild herbivores on butterflies in an African savanna. Ecology and Evolution 3:3672-3682.


Progress 01/01/12 to 12/31/12

Outputs
OUTPUTS: Our research examines various aspects of ecological restoration, particularly in the context of California's grassland/rangeland ecosystems, and also in nearby or ecologically similar ecosystems. In the past year, the three main areas of research (data collection, analysis and synthesis) in our lab have been 1) examination of the role of contingency in ecological restoration, including year effects and both spatial and temporal priority effects, 2) studies of post-fire regeneration of Sierra Nevada trees, 3) the potential use of ecological restoration in mitigating the effects of climate change, and 4) parallel research on the management and restoration of similar grassland/rangeland systems in Africa. This research is published in major peer-reviewed journals (see below). In the last year, my lab and I also have made multiple presentations at the annual meetings for the Society for Ecological Restoration, the Ecological Society of America, and the Northern California Botanists. PARTICIPANTS: PI: Truman Young, Professor Graduate Student researchers: Lauren McGeoch, Marit Wilkerson, Starry Sprenkle, Kevin Welch, Jen Balachowski, Emily Peffer, Kelly Gravuer, Steve Fick, Derek Young, Laura Morales, Mila Hickenbottom, Kristina Wolf, Grace Charles Undergraduate Research assistants: Alexander Kouxoukis, Alicia Pharr, Austen Apigo, Genevieve Perdue Post-doctoral associates: Wilfred Odadi, Corinna Riginos, Kurt Vaughn, Lauren McGeoch TARGET AUDIENCES: Target Audiences: Restoration practitioners (including agencies and NGOs); rangeland managers; graduate and undergraduate students. Efforts include teaching "Plant Communities of California", directing undergraduate internships in restoration, and managing the "restecol" listserv, which is a local and regional clearinghouse for restoration meetings, jobs, and volunteer and internship opportunities to over 150 subscribers. PROJECT MODIFICATIONS: Since 2012, part of a team lead by Val Eviner receiving grants from ANR and WSAREP: "Interactive effects of environment and management on multiple ecosystem services: decision-support for site-specific rangeland management". Also, renewed support from USFS for post-fire regeneration research.

Impacts
Recent outcomes/impacts of our work have been: 1) The demonstration that planting spatially heterogeneous patches of species can increase the resultant species diversity in restored grasslands, by creating temporal priority for subordinate species. 2) Demonstration of multiple positive and negative interactions between livestock management and biodiversity in Africa. 3) I also handle numerous telephone and email queries each year concerning ecological restoration, and manage the "restecol" listserv, which is a local and regional clearinghouse for restoration meetings, jobs, and volunteer and internship opportunities to over 200 subscribers. 4) Several of the graduate students in my lab were active in 2012 as mentors for the SLEWS program that brings (often disadvantaged) high school students to local farms and ranches to assist in restoration and land management projects.

Publications

  • Lab Publications Porensky, L.M., K.J. Vaughn & T.P. Young. 2012. Can initial intraspecific spatial aggregation increase multi-year diversity by creating temporal priority Ecological Applications 22:927-936.
  • Lulow, M.E. and T.P. Young. 2012. Is there still native diversity in California grasslands Fremontia 39(2/3):6-11.
  • Riginos, R., L.M. Porensky, K.E. Veblen, W.O. Odadi, R.L. Sensenig, F. Keesing, D. Kimuyu, M.L. Wilkerson, and T.P. Young. 2012. Lessons on the relationship between pastoralism and biodiversity from the Kenya Long-term Exclosure Experiment (KLEE). Pastoralism: Research, Policy and Practice 2012 2:10. http://www.pastoralismjournal.com/content/2/1/10
  • Isbell, L.A., T.P. Young, and A.H. Harcourt. 2012. Stag parties linger: continued gender bias in a female-rich scientific discipline. PLoS ONE 7(11):e49682.
  • Odadi, W.O.O., M. Jain, S.E. Van Wieren, H.H.T. Prins and D.I. Rubenstein. 2012. Facilitation between bovids and equids on an African savanna. Evolutionary Ecology Research 13:237-252.
  • Veblen, K.E. 2012. Savanna glade hotspots: Plant community development and synergy with large herbivores. Journal of Arid Environments 78:119-127.
  • Porensky, L.M. and K.E. Veblen. 2012. Grasses and large herbivores reinforce landscape heterogeneity by excluding a savanna tree from ecosystem hotspots. Oecologia 168:749-759.
  • Clary, J.J. 2012. Perennial grass persistence in California grasslands driven by distance from coast. Plant Ecology 213:1203-1209.


Progress 01/01/11 to 12/31/11

Outputs
OUTPUTS: Our research examines various aspects of ecological restoration, particularly in the context of California's grassland/rangeland ecosystems, and also in nearby or ecologically similar ecosystems. In the past year, the three main areas of research (data collection, analysis and synthesis) in our lab have been 1) examination of the role of contingency in ecological restoration, including year effects and both spatial and temporal priority effects, 2) the potential use of ecological restoration in mitigating the effects of climate change, and 3) parallel research on the management and restoration of similar grassland/rangeland systems in Africa. This research is published in major peer-reviewed journals (see below). In the last year, my lab and I also have made multiple presentations at the annual meetings for the Society for Ecological Restoration, the Ecological Society of America, the Society for Conservaton Biology, and the Northern California Botanists. PARTICIPANTS: PI: Truman Young, Professor Graduate Student researchers: Kurt Vaughn, Lauren McGeoch, Marit Wilkerson, Starry Sprenkle, Kevin Welch, Jen Balachowski, Emily Peffer, Kelly Gravuer, Steve Fick, Derek Young, Laura Morales Undergraduate Research assistants: Alexander Kouxoukis, Alicia Pharr Post-doctoral associates: Wilfred Odadi, Corinna Riginos Partner Organizations: Mpala Research Centre. Training: Graduate training provided for Kurt Vaughn, Lauren McGeoch, Marit Wilkerson, Starry Sprenkle, Wilfred Odadi, Kevin Welch, Jen Balachowski, Amy Wolf, Emily Peffer, Kelly Gravuer, Steve Fick, Derek Young, and Laura Morales. Undergraduate training for Alexander Kouxoukis and Alicia Pharr, and via field course, "Plant Communities of California". Oversaw the Restoration Practicum. Field Assistant Training for Frederick Erii, John Lochukuya, and Matthew Lokidongoi. TARGET AUDIENCES: Restoration practitioners (including agencies and NGOs); graduate and undergraduate students. Efforts include teaching "Plant Communities of California", directing undergraduate internships in restoration, and managing the "restecol" listserv, which is a local and regional clearinghouse for restoration meetings, jobs, and volunteer and internship opportunities to over 150 subscribers. PROJECT MODIFICATIONS: In 2011, received an five-year NSF grant, "Historical contingency in ecology and restoration: climate change, year effects, and priority effects in California grasslands"

Impacts
Recent outcomes/impacts of our work have been: 1) The demonstration that California native perennial grasses behave more like annuals than do Mediterranean perennial grasses, which may help explain the success of invasive annuals into California's rangeland ecosystems. 2) Demonstration of multiple positive interactions between livestock management and biodiversity in Africa, which mitigate their negative effects (which we also document). 3) Graduate students and a post-doc in our lab created user manuals for rangeland monitoring in Africa. 4) I also handle numerous telephone and email queries each year concerning ecological restoration, and manage the "restecol" listserv, which is a local and regional clearinghouse for restoration meetings, jobs, and volunteer and internship opportunities to over 175 subscribers

Publications

  • Young, T.P. & K.J. Vaughn. 2011. Restoration. Pp. 594-597 in: Encyclopedia of Invasive Introduced Species. D. Simberlof & M. Rejmanek (eds.), University of California Press. Augustine, D.J., K.E. Veblen, J.R. Goheen, C. Riginos & T.P. Young. 2011. Pathways for positive cattle-wildlife interactions in semi-arid rangelands. Smithsonian Contributions to Zoology 632:55-71. Vaughn, K.J., C. Biel, F. de Herralde, X. Aranda, J.J. Clary, R.Y. Evans, T.P. Young & R. Save. 2011. California perennial grasses are physiologically distinct from both Mediterranean annual and perennial grasses. Plant & Soil 345:37-46. Odadi, W.O., S.A. Abdulrazak, M.M. Karachi & T.P. Young. 2011. African wild ungulates compete with or facilitate cattle depending on season. Science 333:1753-1755.


Progress 01/01/10 to 12/31/10

Outputs
OUTPUTS: Our research examines various aspects of ecological restoration, particularly in the context of California's grassland/rangeland ecosystems, and also in nearby or ecologically similar ecosystems. In the past year, the three main areas of research (data collection, analysis and synthesis) in our lab have been 1) examination of the role of contingency in ecological restoration, including year effects and both spatial and temporal priority effects, 2) evaluation of the cost effectiveness of different seeding and planting techniques in various restoration settings, and 3) parallel research on the management and restoration of similar grassland/rangeland systems in Africa. This research is published in major peer-reviewed journals (see below). In the last year, my lab and I also have made multiple presentations at the annual meetings for the Society for Ecological Restoration, the Ecological Society of America, and the Northern California Botanists. PARTICIPANTS: Individuals: PI: Truman Young, Professor Graduate Student researchers: Kurt Vaughn, Lauren McGeoch, Marit Wilkerson, Wilfred Odadi, Starry Sprenkle, Kevin Welch, Jen Balachowski, Emily Peffer Undergraduate Research assistant: Laura Calbert Partner Organizations: Mpala Research Centre. Training: Graduate training provided for Kurt Vaughn, Lauren McGeoch, Marit Wilkerson, Starry Sprenkle, Wilfred Odadi, Kevin Welch, Jen Balachowski, Amy Wolf, and Emily Peffer. Undergraduate training via field course, "Plant Communities of California". Oversaw the Restoration Capstone Experience. Field Assistant Training for Frederick Erii, John Lochukuya, and Matthew Lokidongoi. TARGET AUDIENCES: Target Audiences: Restoration practitioners (including agencies and NGOs); graduate and undergraduate students. Efforts include teaching "Plant Communities of California", directing undergraduate internships in restoration, and managing the "restecol" listserv, which is a local and regional clearinghouse for restoration meetings, jobs, and volunteer and internship opportunities to over 150 subscribers. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.

Impacts
Recent outcomes/impacts of our work have been 1) our recent experiments designed to test the cost effectiveness of different species and different planting techniques, 2) in particular, demonstrating that direct seeding is often more cost-effective than using container stock, and 3) creating a restoration prescription (now in use) for repairing degraded rangelands in Kenya. I also handle numerous telephone and email queries each year concerning ecological restoration.

Publications

  • Palmerlee, A.P. & T.P. Young. 2010. Direct seeding is more cost-effective than planting container stock across ten woody species in California. Native Plants Journal 11:89-102.
  • Young, T.P. & E. Peffer. 2010. "Recalcitrant understory layers" revisited: arrested succession and the long life spans of clonal mid-successional species. Canadian Journal of Forest Research 40:1184-1188.
  • Kinyua, D.M., L.E. McGeoch, N. Georgiadis & T.P. Young. 2010. Short-term and long-term effects of tilling, fertilization, and seeding on the restoration of a tropical rangeland. Restoration Ecology 18S1:226-233.
  • Vaughn, K.J. & T.P. Young. 2010. Contingent conclusions: year effects influence the results of ecological field experiments, but temporal replication is rare. Restoration Ecology 18S1:59-64.
  • Veblen K.E. & T.P. Young. 2010. Contrasting effects of cattle and wildlife on the vegetation development of a savanna landscape mosaic. Journal of Ecology 98:993-1001.
  • Vaughn, K.J., L.M. Porensky, M.L. Wilkerson, J. Balachowski, E. Peffer, C. Riginos & T.P. Young. 2010. Restoration Ecology. Nature Education Knowledge 1(8):66. http://www.nature.com/scitable/knowledge/library/restoration-ecology- 13339059
  • Erwin, T.L. & T.P. Young. 2010. A native besieged: the effects of non-native frugivores and ground vegetation on fruit removal in a highly endangered Hawai'ian shrub, Delissea rhytidosperma (Campanulaceae). Pacific Science 64:33-43.


Progress 01/01/09 to 12/31/09

Outputs
OUTPUTS: Our research examines various aspects of ecological restoration, particularly in the context of California's grassland/rangeland ecosystems, and also in nearby or ecologically similar ecosystems. In the past year, the three main areas of research (data collection, analysis and synthesis) in our lab have been 1) examination of the role of contingency in ecological restoration, including year effects and both spatial and temporal priority effects, 2) evaluation of the cost effectiveness of different seeding and planting techniques in various restoration settings, and 3) parallel research on the management and restoration of similar grassland/rangeland systems in Africa. This research is published in major peer-reviewed journals (see publications). In the last year, my lab and I also have made multiple presentations at the annual meetings for the Society for Ecological Restoration, the Ecological Society of America, and the California Native Grasslands Association (where I gave a plenary talk in 2009). PARTICIPANTS: PI: Truman Young, Professor. Graduate Student researchers: Kurt Vaughn, Lauren McGeoch, Marit Wilkerson, Starry Sprenkle, Wilfred Odadi. Undergraduate Research assistant: Laura Calbert. Partner Organizations: IRTA, University of Barcelona; Mpala Research Centre. Training: Graduate training provided for Kurt Vaughn, Lauren McGeoch, Marit Wilkerson, Starry Sprenkle, Wilfred Odadi, Bell Okello, Kevin Welch, Jen Balachowski, Amy Wolf, and Emily Peffer. Undergraduate training via field course, "Plant Communities of California". Field Assistant Training for Frederick Erii, John Lochukuya, and Matthew Lokidongoi. TARGET AUDIENCES: Target Audiences: Restoration practitioners (including agencies and NGOs), graduate and undergraduate students. Efforts include teaching "Plant Communities of California", directing undergraduate internships in restoration, and managing the "restecol" listserv, which is a local and regional clearinghouse for restoration meetings, jobs, and volunteer and internship opportunities to over 150 subscribers. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.

Impacts
Recent outcomes/impacts of our work have been 1) our recent experiments designed to test the cost effectiveness of different species and different planting techniques, 2) in particular, demonstrating that direct seeding is often more cost-effective than using container stock, and 3) creating a restoration prescription (now in use) for repairing degraded rangelands in Kenya. I also handle numerous telephone and email queries each year concerning ecological restoration.

Publications

  • Odadi, W., Young, T.P., and Okeyo-Owuor, J. 2009. The effects of wild herbivores on cattle intake and movement rates in Laikipia rangeland, Kenya. Applied Animal Behavior Research 116:120-125.
  • Veblen, K.E. and Young, T.P. 2009. A California grasslands alkali specialist, Hemizonia pungens ssp. pungens prefers non-alkali soil. Journal of Vegetation Science 20:170-176.
  • Lulow, M.E. and Young, T.P. 2009. High native forb richness in Central Valley "grassland" sites in the western Sacramento Valley and adjacent foothills. Grasslands 14(3):7-11.
  • Riginos, C., Grace, J.B., Augustine, D.J., and Young, T.P. 2009. Local versus landscape-scale effects of savanna trees on grasses. Journal of Ecology 97:1337-1345.


Progress 01/01/08 to 12/31/08

Outputs
OUTPUTS: Our research examines various aspects of ecological restoration, particularly in the context of California's grassland/rangeland ecosystems, and also in nearby or ecologically similar ecosystems. In the past year, the three main areas of research in our lab have been 1) examination of the role of contingency in ecological restoration, including year effects and both spatial and temporal priority effects, 2) evaluation of the cost effectiveness of different seeding and planting techniques in various restoration settings, and 3) parallel research on the management and restoration of similar grassland/rangeland systems in Africa. PARTICIPANTS: Nothing significant to report during this reporting period. TARGET AUDIENCES: Restoration practitioners, graduate students, undergraduate students. Efforts: Classes Taught: Foundations of Restoration Ecology (ECL 290- 10 graduate students) Introduction to Environmental Plants (EHN6- 80 undergraduate students) Fire Ecology (ERS 141-25 graduate and undergraduate students) California's Plant Communities (PLS 147-30 undergraduate students; lecture and field course). Guest lectures in: Agroforestry (AMR 160) and Tropical Ecology (DES 220). Innovative teaching/ experiential learning opportunities: Developed a capstone experience in restoration for a select groups of motivated graduate and undergraduate students, who were matched with local restoration practitioners (at Bobcat Ranch and Yolo Audubon) for field days with active restoration projects. PROJECT MODIFICATIONS: Not relevant to this project.

Impacts
Recent applications of our research to practitioners ("change in actions") have been 1) our demonstration of the survivability of restoration plantings in the face of weed control burns, 2) our recent experiments designed to test the cost effectiveness of different species and different planting techniques, and 3) in particular, demonstrating that direct seeding is often more cost-effective than using container. I handle numerous telephone and email queries each year concerning ecological restoration. I manage the "restecol" listserv, which is a local and regional clearinghouse for restoration meetings, jobs, and volunteer and internship opportunities to over 100 subscribers. In the last year, my lab and I also have made ten presentations at the annual meetings for the Society for Ecological Restoration, the Ecological Society of America, and the Society for Conservation Biology.

Publications

  • Infalt, S.B. and Young, T.P. 2008. Forest restoration of campsites at Kings Canyon National Park, California. Ecological Restoration 26:302-310.
  • Holmes, K.A., Veblen, K.E., Young, T.P. and Berry, A.M. 2008. California oaks and fire: a review and case study. Pages 551-565 in: Merenlender, A., D. McCreary, and K.L. Purcell, eds. Proceedings of the Sixth California Oak Symposium. General Technical Report PSW-GTR-217. Albany, CA.
  • Ingolia, M., Young, T.P. and Sutter, E.G. 2008. Germination ecology of Rorippa subumbellata (Tahoe yellow cress), an endangered, endemic species of Lake Tahoe. Seed Science and Technology 36:621-632.
  • Riginos, C. and Young, T.P. 2008. Positive and negative effects of grasses and wild and domestic herbivores on Acacia saplings. Oecologia 153:985-995.
  • Palmer, T.M., Stanton, M.L., Young, T.P., Goheen, J.R., Pringle, R.M. and Karban, R. 2008. Breakdown of an ant-plant mutualism following the loss of large herbivores from an African savanna. Science 319:192-195.
  • Ogada, D., Gadd, M.E., Ostfeld, R.S., Young, T.P. and Keesing, F. 2008. Impacts of large herbivores on bird diversity and abundance in an African savanna. Oecologia 156:387-397.
  • Okello, B.D., Young, T.P., Riginos, C., Kelly, D. and O'Connor. T. 2008. Short-term survival and long-term mortality of Acacia drepanolobium after a controlled burn in Laikipia, Kenya. African Journal of Ecology 46:395-401.
  • Veblen, K.E. 2008. Season- and herbivore-dependent competition and facilitation in a semi-arid savanna. Ecology 89:1532-1540.
  • Sprenkle, S.D. 2008. Restoration in a failed state: community-based agroforestry in Haiti. Ecological Restoration 26:97-100.
  • Riginos, C. and Grace, J.B. 2008. Tree density affects wild ungulate habitat use and herbaceous community characteristics in a Kenyan savanna. Ecology 89:2228-2238.
  • Sprenkle, S.D. 2008. Community-based agroforestry as restoration: the Haiti timber re-introduction project methods and framework. Ecological Restoration 25:201-203.


Progress 01/01/07 to 12/31/07

Outputs
Our research examines various aspects of ecological restoration, particularly in the context of California's grassland/rangeland ecosystems, and also in nearby or ecologically similar ecosystems. In the past year, the three main areas of published research to come out of our lab have been 1) how biogeographic evolutionary history affects the eco-physiology and morphology of native and invasive grasses in the context of California grasslands, 2) the examination of germination and planting techniques in various restoration settings, and 3) the role of commercial nurseries in controlling the spread of invasive species. 1) In an intercontinental comparison, Jeffrey Clary has demonstrated that the dominance of California's Central Valley by Mediterranean annual grasses was explicable in part by its exceedingly low summer rainfall, relative to Iberia (Clary, in press), and a survey of coast-interior climatic gradients in the California also support this. We are now in the process of demonstrating that native California perennial grasses are in many ways intermediate between Mediterranean annuals and perennials eco-physiologically and morphologically, and in other ways are distinctly more drought adapted than either of them. 2) We carried out field trials and research on the propagation limiting restoration in a wide variety of ecosystems, including Lake Tahoe shorelines and Sierra Nevada forests. We did the first cost-effectiveness analysis of the relative values of direct seeding and container stock in native California native woody species in wooded grasslands that demonstrated that direct seeding was always more cost-effective, and that this advantage increased with increasing seed size. All of these are being prepared for publication. 3) Commercial nurseries are one of the primary sources of new invasive plant species in the United States, and particularly in California. One of the students in my lab, Kari Veblen, was part of a study examining the level of awareness of this problem among Bay Area nurseries, and their willingness to be part of the solution (Burt et al. 2007). In addition, I continue to carry our parallel research on the management and restoration of similar grassland/rangeland systems in Africa (Odadi et al. 2007)

Impacts
The repair of California's natural and anthropogenic ecosystems in increasingly a major goal of land managers, but until recently these efforts have been carried out with only rudimentary understanding of restoration goals and how best to achieve them. My lab continues to carry out applied research in ecological restoration, seeking to both help solve the practical problems faced by practicing restorationists, and to address the underlying concepts and principles of restoration ecology. Specifically: 1) As of this year, we now have two separate demonstrations of greater success in restoration of large-seeded species, one for native perennial grasses (Lulow et al. 2007), and one for native woody species (Palmerlee 2007). The former is useful in calculating seeding rates. The latter helps support our recommendations favoring direct seeding of woody species over planting container stock, especially for large-seeded species, which are being adopted by more and more restoration practitioners, resulting in considerable cost savings. 2) Mia Ingolia's more effective germination prescriptions of endangered Tahoe Yellow Cress (Ingolia 2006) are being implemented by recovery projects. 3) My talk at the 2007 annual meeting of the Society for Ecological restoration on establishment niches has changed the way at least one colleague implements restoration projects in Australia. I handle numerous telephone and email queries each year concerning ecological restoration. I manage the "restecol" listserv, which is a local and regional clearinghouse for restoration meetings, jobs, and volunteer and internship opportunities, with hundreds of postings each year to over 100 subscribers. In the last year, my lab and I also have made ten presentations at the annual meetings for the Society for Ecological Restoration, the Ecological Society of America, and the Society for Conservation Biology.

Publications

  • Burt, J.W., Muir, A.A., Piovia Scott, J., Veblen, K.E., Chang, A.L., Grossman, J.D. and Weiskel, H.W. 2007. Preventing horticultural introductions of invasive plants: potential efficacy of voluntary initiatives. Biological Invasions 9:909-923.
  • Odadi, W.O., Young, T.P. and Okeyo-Owuor, J.B. 2007. The effects of wild herbivores on cattle diet in Laikipia rangeland. Rangeland Ecology and Management 60:179-185.
  • Clary, J.J. 2008. Rainfall seasonality determines annual/perennial grass balance in vegetation of Mediterranean Iberian. Plant Ecology (in press).


Progress 01/01/06 to 12/31/06

Outputs
Our research examines various aspects of ecological restoration. in the past year, the three mian areas of published work have been 1)restoration of California grasslands, 2) an analysis of the socio-economic underpinnings of land abandonment, and 30 to implications of controlled burns for restoration plantings. Our research in California grasslands restoration has included both conceptual and applied work. Publication #2 examines alkali ecotypes of the invasive grass Lolium multiflorum. generally, harsh edaphic sites (such as serpentine outcrops, vernal pools an dalkali sinks) have been very resistant to the wholesale invasion that characterizes so much of California's rangelands, making them important refuges for native species, many of which are endemic. for the first time, we provide evidence that at least one invasive species is evolving ecotypes that may foretell their invasion into these edaphic refuge communities. Publication #3 is a review of the current state of our knowledge of the ecological restoration of California grasslands. In it, we review the ecological history of these grasslands and the disturbances that have degraded them, discuss the various restoration goals and what limits their success, and outline some guidelines for grassland restoration. Publication #6 reports on a grassland restoration project in Yolo County. We show that the most planted native grass species fared far better on north-facing slopes and in areas free from Erodium, but that this was not true of nassella pulchra. this may explain both the popularity of Nassella among restorationists, and its abundance in relict grassland sites, which may therefore be revealed to be atypical. We also did the first cost-effectiveness analysis of California native grass restoration that demonstrates that larger-seed species fare better than smaller-seeded species, but (generally) in direct proportion to their size and cost.The socio-economic context of restoration is also an interest of mine. Agricultural land abandonment has long been recognized as one of the drivers of ecological restoration in the developed world. I have recently analyzed this same phenomenon in the developing world. I demonstrate that extractive economies are unlikely to be engines of significant rural poverty reduction at current population densities, and that rural population sizes consequently are already in decline in much of the developing world. The resultant land abandonment provides a growing global opportunity for ecological restoration and biodiversity conservation. Publications 4 & 5 report on how (controlled) burns affect restoration planting of oaks and grasses. Fire is an increasingly important management tool for invasives in restoration setting, but little is known about its effects on planted species. Publication 4 is a review and meta-analysis of past research on oaks and fire in California, supported by preliminary data from our own burn experiments, showing that although smaller oaks are prone to top-kill, oaks of all sizes and all species have high overall survival rates.

Impacts
The repair of California's natural and anthropogenic ecosystems in increasingly a major goal of land managers, but until recently these efforts have been carried out with only rudimentary understanding of restoration goals and how best to achieve them. My lab continues to carry out applied research in ecological restoration, seeking to both help solve practical problems faced by practicing restorationists and to address the underlying concepts and principles of restoration ecology. Specifically: 1)Our grassland research is providing useful guidelines for more effective restoration, including specific prescriptions for restoring California grasslands that are currently severely invaded by exotic annual plants. 2)Our fire research suggests that weed control burns can be carried out even after restoration plantings, although at some cost to both woody species and grasses. I handle numerous telephone and email queries each year concerning ecological restoration. I manage the 'restecol' listserv, which is a local and regional clearinghouse for restoration meetings, jobs, and volunteer and internship opportunities, with hundreds of postings each year to over 100 subscribers. My lab also has made presentations at meetings directed toward end-users, including the 6th California Oak Symposium and the Laikipia Wildlife Forum annual meeting. I was interviewed for an article on ecological restoration that appeared in the Fall 2004 issue of California Coast & Ocean, and for a June 2005 article in ScienceAction, the CalFed newsletter.

Publications

  • Young, T.P. 2005. Assembly Rules and Restoration Ecology, by V.K. Temperton et al. Journal of Environmental Management 32:98-99. Young, T.P. 2006. Restoration Ecology, by J. Van Andel and J. Aronson. Environmental Conservation 33:82-83.
  • Young, T.P. 2006. Declining rural economies and the future of biodiversity: missing the forest for the trees? Journal of International Wildlife Law & Policy, in press.
  • Dawson, K., T.P. Young & K.E. Veblen. 2006. Alkali ecotypes in an invasive annual grass, Lolium multiflorum. Biological Invasions, in press.
  • Stromberg, M., T.P. Young, J. Wirka & P. Kephart. 2007. California Grassland Restoration. To appear in: Stromberg, M., J.D. Corbin, and C.M. D Antonio (eds). Ecology and Management of California Grasslands. University of California Press.
  • Veblen, K.E., K.A. Holmes, K.A., T.P. Young, & A.M. Berry. 2007. Effects of prescribed fires on native grass plugs at a research restoration site in the Sacramento Valley. Ecological Restoration, in press.
  • Holmes, K.A., K.E. Veblen, T.P. Young, & A.M. Berry. 2007. Effects of fire on oaks of different sizes. Proceedings of the 6th California Oak Symposium. In press.
  • Lulow, M.E., T.P. Young, J.L. Wirka & J.H. Anderson. 2007. Variation in the initial success of seeded native bunchgrasses in the rangeland foothills of Yolo County, California. Ecological Restoration, in press.


Progress 01/01/05 to 12/31/05

Outputs
Our research examines various aspects of ecological restoration. In the past year, the three main areas of research have been 1) restoration of California grasslands, 2) synthetic review of restoration ecology, and 3) woody plant restoration. All of the people mentioned below are graduate students in my lab. 1) Debbie Petersen's annual grassland research ahs found that most species are seed-limited in the Vina annual grasslands, but that guilds are not, nor is the community as a whole. Seeding of individual species increased the abundance of that species, but always at the expense of (only) other species in the same guild (i.e., grass, forbs). We are also extending our physiological comparisons of native perennial grasses, Mediterranean perennial grasses, and Mediterranean annual grasses. These studies are beginning to show anomalous physiologies and life histories for California native perennial grasses, which might be related to the unique climate of the Central Valley. 2) With help from two of my graduate students, I wrote a major synthetic review of the past, present, and future conceptual bases for restoration ecology as an invited paper for Ecology Letters. We suggest that the science of restoration ecology has been more effective in influencing the practice of ecological restoration than its sister science, conservation biology, has been in influencing the practice of biological conservation. We also highlight several areas of conceptual ecology that we think are particularly relevant to restoration, and for which restoration may provide the ideal experimental settings. These include the roles of historical contingency and ontogeny on the ecologies of populations. 3) Our research on the restoration of woody species has proceeded on several fronts. A) We continue to oak survival and growth in monitor our replicated fire plots. We are particularly interested in seeing whether and how heavily coppicing oaks reduce their coppices down to one or a two leader. One surprise is that several individuals that appeared dead during the several months after the fire have now resprouted in a hitherto undescribed delayed coppicing This suggests that traditional (short-term) post-fire monitoring overestimates oak mortality. B) Susan Infalt's work at King's Canyon has revealed that direct seedling is a viable option for campground restoration, and that gypsum and humus interact in strikingly synergistic ways as soil modifiers for restoration. C) Alex Palmerlee has shown that direct seeding is more cost effective than container stock for an entire suite of Central Valley riparian trees and shrubs.

Impacts
Our research is designed to help restoration projects be more effective. The Vina Plains research was done specifically to assist The Nature Conservancy in developing post-fire seed mixes for this annual grassland habitat. Debbie Petersen's final report to TNC has already been widely distributed, and well-received. The work at King's Canyon was also elicited by a specific request from the National Park Service. Susan Infalt's results are already beginning to affect campground restoration in the Park, an we plan to disseminate this information more broadly to agencies with similar problems. Our several research projects demonstrating that direct seeding is more cost-effective than container stock (at least for woody plants) is supporting a broad change in the way the woody plant restoration is done. As part of my public outreach, I made the presentation 'Restoration Ecology: Agriculture in the Service of Nature' at the Plant Sciences Symposium, 'Plant Sciences in the 21st Century on 26 September 2005.' I also field dozens of calls and emails each year, providing information and contacts on various restoration issues.

Publications

  • Young, T.P., D.A. Petersen & J.J. Clary. 2005. The ecology of restoration: historical links, emerging issues, and unexplored realms. Ecology Letters 8:662-673.
  • Huddleston, R.T & T.P. Young. 2005. The effects of weed control and soil amendments on exotic species and planted native grasses in an Oregon grassland. Western North American Naturalist 65:507-515.
  • Deering, R.H. & T.P. 2005 The potential use of seed priming to reduce the initial advantage of exotic annual grasses over native perennials in restoration. Grasslands, in press.
  • Publications since last report 2005 (not including those listed as "in press" in last years report)
  • Young, T.P. & R.Y. Evans. 2005. Effects of containers and irrigation regimes on initial seedling survival and growth in Valley Oak (Quercus lobata). Native Plants Journal 6:83-90.


Progress 01/01/04 to 12/31/04

Outputs
Our research examines various aspects of ecological restoration. In the past year, the three main areas of research have been 1) the effects of fire on regenerating restoration plantings of valley oak (Quercus lobata); 2) restoration of California grasslands, and 3) a comparison of annual and perennial grasses in the context of restoration in California and Catalonia. 1) We carried out our first controlled burns at these plots in July 2003. In June 2004, we carried out our second of three planned burns. Initial results suggest fires are rarely fatal to oaks of any size. Smaller oaks may experience top-kill, and larger trees can experience bark damage, both of these classes readily coppice to produce healthy new shoots. In our first burn we estimated fire temperature using standard method: temperature -sensitive paints on ceramic tiles placed in the fire zone. Estimates of fire temperatures from these tiles seemed low (<250 degrees C), and we wondered whether fast-burning grass fire may not have enough time to heat up these thick tiles to actual fire temperatures. In our second burn (2004) we paired ceramic tiles with aluminum tags. We found that the aluminum tags recorded fire temperatures that were 50-100 degrees C higher than their paired ceramic tiles. It is not yet clear, however, which methods most accurately records 'effective' temperatures for these thick-barked trees. 2) Our grassland restoration projects continue to be productive. Our studies of priority effects have run for another year, and these show continued community convergence. A series of burning/mowing/herbicide experiments in both restored perennial grasslands in Yolo County and native annual grasslands in Lassen have shown mixed results that are context-dependent on plant guild, treatment timing, treatment combination, and year effects. These 'year effects' have profound effects on restoration success, and we plan to study them in more detail in coming years. 3) Jeffrey Clary's regional surveys in Spain and Portugal have now been formally analyzed with logistic fits. They show that both summer rain and (to a much lesser extent) disturbance explain much of the variation in relative annual/perennial grass cover in the Iberian peninsula. Ordination analyses support this pattern, and also show that bare ground was positively associated with the perennial grass stands. One of the key questions in California grassland restoration is what originally occurred in the interstices between perennial grass tussock now filled by exotic annual grasses. These results suggest that there may have been considerable bare ground in these microsites. California surveys completed this year suggest that here, too, summer precipitation is a key to the annual/perennial grass composition, but here the analysis is complicated by the occult (mist) summer precipitation of coastal sites, which have been more resistant to invasion by exotic annuals.

Impacts
Our research is specifically designed to help restoration projects be more effective. Each of our projects has direct and indirect implications for restoration, and we have been active in disseminating this information. In the past 12 months, we have made the following presentations: 1) Megan Lulow gave a presentation on components of the forb study was given at the annual meeting for the Society of Ecological Restoration International November 22, 2003. 2) Our lab (Megan Lulow, Jeffrey Clary, and I) participated in an Audubon mini-symposium in Dec 2003, summarizing the results of our three years CalFed research. 4) I served as the Moderator of the Restoration Panel at the California Grasslands Conference at Berkeley, 2-3 April 2004, at which Megan Lulow and I presented an oral paper. 5) I presented a summary of the last four years of our restoration research at the 3rd Biennial CalFed Bay-Delta Science Conference on 8 October 2004. 6) I gave a presentation on rangeland restoration to the Agronomy Continuing Conference at UC Davis on 5 May 2004. 7) I presented a paper on rangeland stability at the 2004 annual meeting of the Ecological Society of America in August of this year. In addition, I was a contributor to ten seminar and poster sessions in the last two years, and was the presenter for five of these.

Publications

  • Young, T.P. and Johnson, D. 2004. Restoration. Noxious Times 5(4):10.
  • Huddleston, R.T. and Young, T.P. 2004. Spacing and competition between planted grass plugs and pre-existing perennial grasses. Restoration Ecology 12:545-550.
  • Kostel-Hughes, F., Young, T.P. and Weir, J.D. 2005. Emergence and seedling growth of native and non-native trees species in response to leaf litter depth. Journal of the Torrey Botanical Society (In press)
  • Young, T.P. 2005. Assembly Rules and Restoration Ecology. Journal of Environmental Management (Book Review, In press).


Progress 01/01/03 to 12/31/03

Outputs
Our research examines various aspects of ecological restoration. The three main areas of research are 1) the effects of horticultural practice on ecological restoration, in the context of valley oak (QUERCUS LOBATA); 2) the effects of competition on the success of restoration, particularly in the context of California's grasslands and oak woodlands, and 3) a comparison of restoration issues in California and Catalonia. 1) Our initial oak research project is now in press in the Native Plants Journal. We carried out our first controlled burns at these plots in July 2003. Initial results suggest fires may top-kill to smaller oaks, but that oaks of all sizes survive such burns, though sprouting if necessary. 2) Our grassland restoration projects continue to be productive. It appears that giving initial priority (earlier planting) to grasses has little long-term impact on community structure, but that the only communities where forbs are retained in substantial numbers are those where the forbs got a year's head start on the competing vegetation. This has important implications for how we think about priority effects, and also for how we may need to modify our planting schedules for grassland restoration. We also have the first experimental confirmation of the suspicion that there are good forb years and good grass years, and that these differ. 3) Jeffrey Clary's regional surveys in Spain have now demonstrated that throughout the Iberian Peninsula, the proportion of species in grasslands that are annuals is strongly negatively correlated with the amount of summer rainfall. This a) may explain the susceptibility to invasion by annuals of Central Valley grasslands, and b) suggests that summer watering may be an effective tool for shifting the balance from exotic annuals to native perennials in California. We are beginning studies to address this latter possibility.

Impacts
Our research is specifically designed to help restoration projects be more effective. Megan Lulow was a presenter in a Grass Identification and Revegetation Workshop with the Solano County RCD on September 25, 2003. In addition, a presentation on components of the forb study was given at the annual meeting for the Society of Ecological Restoration International November 22, 2003. Our lab (Megan Lulow, Jeffrey Clary, and I) participated in an Audubon mini-symposium in Dec 2003, summarizing the results of our three years CalFed research.

Publications

  • LULOW, M.E. and YOUNG, T.P. 2003. Calfed Annual Report 2, Project 01-N31, "Correlates of Successful Native Perennial Grass Establishment and Enhancing Biodiversity with Native Forbs in Ecological Restoration of Annual Rangelands" YOUNG, T.P. and EVANS, R.Y. Effects of containers and irrigation regimes on initial seedling survival and growth in Valley Oak (QUERCUS LOBATA). Native Plants Journal, in press.


Progress 01/01/02 to 12/31/02

Outputs
Our research examines various aspects of ecological restoration. The three main areas of research are 1) the effects of horticultural practice on ecological restoration, in the context of valley oak (Quercus lobata); 2) the effects of competition on the success of restoration, particularly in the context of California's grasslands and oak woodlands, and 3) a comparison of restoration issues in California and Catalonia. Our initial oak research project has been completed. We are now using these plantings to do a field trial on the effects on the survivorship of valley oak saplings of controlled burns (used to reduce weed cover). Our field experiments in grassland restoration are showing some great results. We have shown that the success of grassland restoration plantings is influenced by pre-emergent herbicide treatment, slope, and soil type, and that these factors affects different species in different ways. In particular, it appears that NASELLA PULCHRA, the most common native species used in California grassland restoration, has much broader tolerances than other native bunch grasses. Our Catalonia research has also begun to bear fruit. Regional surveys in Spain suggest that the predominance of annuals in invaded California grasslands may be in part due to the severity of our dry summers here, compared with most Mediterranean sites. In addition, our greenhouse experiments in Spain have shown pronounced priority effects between native bunch grasses and native shrubs, suggesting that the order in which these are planted will have profound effects on their relative success in restoration.

Impacts
Our research is specifically designed to help restoration projects be more effective. Our interests in Oak propagation led to a very successful conference for restoration nurseries, attended by over 60 professionals. The grassland research is beginning to reveal the kinds of information needed by restoration practitioners in this critical California ecosystem. We have several mss in preparation for submission to international peer-reviewed journals.

Publications

  • SMITH, S. and YOUNG, T.P. 2002. EH faculty host conference on restoration issues at UCD. Growing Points 6(2):8.
  • YOUNG, T.P., IMMEL, D.L. and CLARY, J. 2003. Historical Ecology, by Egan & Howell. Journal of Environmental Management, in press (book review).
  • YOUNG, T.P. 2003. The State of Restoration. Cal EPPC News (in press).


Progress 01/01/01 to 12/31/01

Outputs
Our research examines various aspects of ecological restoration. The three main areas of research are 1) the effects of horticultural practice on ecological restoration projects has three components, in the context of valley oak (QUERCUS LOBATA); 2) the effects of competition on the success of restoration, particularly in the context of California's grasslands and oak woodlands, and 3) a comparison of restoration issues in California and Catalonia. 1) Our field trail of valley oaks is wrapping up. Three years ago, we planted out several hundred valley oaks plants of differing production history: one year old container stock, three-month old container stock from small containers, three-month old container stock from large containers, and acorns. This experiment is nested into three irrigation treatments: overhead, drip, and none. In the past year, we did root excavations of all combinations of source stock and irrigation regimes. Oaks planted from containers virtually all had malformed roots at depths corresponding to the pot depths. These deformations included severely bent roots and tap root branching (probably related to the death of the original tap root). Water potentials did not differ among treatments (taken after all irrigation had ceased). 2) Our field experiments in grassland restoration are beginning to bear fruit. It appears that the effectiveness of Telar in increasing the establishment of native grasses is strongly related to the first year suppression of annual exotics. These exotics rebounded in the second year, but the perennials were going best in microsites where annuals had been most suppressed in the previous year. Ongoing research is examining additional correlates of restoration success, including local habitat characteristics, and the relative timing of planting. 3) Our Catalonia research has only just begun, but initial research suggests that the Mediterranean species of annual grasses that are so invasive in California are not invasive in Catalonia. The generality of this pattern and its causes are currently under investigation.

Impacts
Our research is specifically designed to help restoration projects be more effective. Our valley oak results suggest that the use of container stock may not be preferable to direct seeding, although this cost appears to be limited to the first year after planting. On the other hand, irrigation does increase growth rates without an apparently weaning cost. The grassland research will continue to refine restoration techniques in this critical California ecosystem.

Publications

  • Hobbs, T. and Young, T.P. 2001. Growing valley oak. Ecological Retoration 19:165-171.
  • Young, T.P. 2001. What is a native? Noxious Times (California Interagency Noxious Weed Coordinating Committee) 3(4):11.
  • Young, T.P. and Evans, R.Y. 2001. Container stock versus direct seeding for woody species in restoration sites. Comb. Proc. International Plant Propagation Society 50:21-25.


Progress 01/01/00 to 12/31/00

Outputs
Our research examines various aspects of ecological restoration. The two main areas of research are 1) the effects of horticultural practice on ecological restoration projects has three components, in the context of valley oak (QUERCUS LOBATA); and 2) the effects of competition on the success of restoration, particularly in the context of California's grasslands and oak woodlands. 1) Our field trail of valley oaks is now in its third year. We planted out several hundred valley oaks plants of differing production history: one-year old container stock, three-month old container stock from small containers, three-month old container stock from large containers, and acorns. We have confirmed our initial finding that oaks planted as acorns have higher survivorship than container stock, especially in unirrigated treatments, but this effect was limited to the first year. Mortality is now limited to the smallest plants. Surviving plants from containers continue to be taller than plants grown from seed. This experiment is nested into three irrigation treatments: overhead, drip, and none. Growth is strongly correlated with the amount of water provided. This year we removed irrigation from half of the irrigated plants. These conditions simulate the techniques of actual restoration projects in the field. It appears that for valley oaks, there is no weaning mortality cost associated with the discontinuation of irrigation (although growth slows appreciably). 2) Our field experiments in grassland restoration are just beginning. Initial results indicate that timely application of herbicide (Telar) greatly reduces cover by exotic annual grasses to the benefit of planted native perennial grasses. Localized application of nitrogen did increase growth rates of planted grasses without increasing the growth of exotic grasses, but this effect was both small and apparently transient. Ongoing research is examining additional correlates of restoration success, including local habitat characteristics, and the relative timing of planting.

Impacts
Our research is specifically designed to help restoration project be more effective. Our valley oak results suggest that the use of container stock may not be preferable to direct seeding, at least for tap-rooting species. On the other hand, irrigation does increase growth rates without an apparent weaning cost. The grassland research will continue to refine restoration techniques in this critical California ecosystem.

Publications

  • Young, T.P. and D.B. Leroy. 2000. Restoration in education - at UC-Davis, the emphasis is on growing a restoration ecology program for the future. Society for Ecological Restoration News 13(1):8.
  • Young, T.P., J.M Chase and R.T. Huddleston. 2001. Community succession and assembly -- comparing, contrasting and combining paradigms in the context of ecological restoration. Ecological Restoration 19:5-18.
  • Hobbs, T. and T.P. Young. 2001. Effects of seed size and condition on germination and early growth in Valley Oak (QUERCUS LOBATA). Ecological Restoration, in press.


Progress 01/01/99 to 12/31/99

Outputs
Our research into the effects of horticultural practice on ecological restoration projects has three components, all in the context of valley oak (QUERCUS LOBATA). 1) We have examined the effects of seed size and condition, and container size, on the germination and early growth of oaks. Although seed weight, cracking, and beetle infestation all significantly effect germination and initial growth, none of these effects were large enough to warrant the time-consuming process of sorting seeds. Seedlings grown in larger containers grew far more quickly than seedlings grown in smaller containers. Even in the large containers, however, tap roots reached the bottoms of the containers very quickly (within seven weeks), at which point they were prone to die. 2) We have now planted out several hundred valley oaks plants of differing production history: one-year old container stock, three-month old container stock from small containers, three-month old container stock from large containers, and acorns. Initial data from the first year of the experiment already shows that oaks planted as acorns have a far higher survivorship than container stock, especially in unirrigated treatments, perhaps because of tap root loss in containers. Surviving plants from containers are taller than plants grown from seed, but only by an amount similar to their initial advantage. There were initial losses to herbivores of both container stock (shoots eaten, but little mortality) and seeds (about 40 percent removed, eaten, and killed), highlighting the need to protect new plantings of some species. 3) We have nested the experiment above into three irrigation treatments: drip, flood, and none. Initial results indicate that oaks in the two irrigated treatments have similar growth rates that are far higher than for oaks in unirrigated treatments. The real test will come this summer, when we plan to stop irrigating half of the irrigated plots (the other half will be irrigated for an additional summer). These conditions simulate the techniques of actual restoration projects in the field.

Impacts
The planting and support of container stock are usually the most expensive and unpredictable parts of restoration projects. Our research is beginning to provide evidence of more cost effective ways of establishing woody species in xeric sites. In particular, initial results suggest that it may be preferable to establish valley oaks from (unsorted) seeds than from (far more expensive) container stock.

Publications

  • Young, T.P. 1999. Restoration ecology takes root at UC Davis. Growing Points 3(1)4.
  • Young, T.P. 2000. Restoration ecology and conservation biology. Biological Conservation 9273 83.