Mason’s : Ten Years Monitoring a Lilaeopsis Metapopulation on the Napa River Megan Keever1, Peggy L. Fiedler2, Jeremy Sarrow3 1Stillwater Sciences, 2855 Telegraph Avenue, Suite 400, Berkeley, CA, 94705, 2Consulting Botanist, 3Watershed and Flood Control Resources Specialist, Napa County Flood Control and Water Conservation District Correspondence should be addressed to [email protected] Want more information? Visit our Lilaeopsis masonii data mashup: http://web.stillwatersci.com/napa/botanicalsurvey.html

Background Lilaeopsis masonii (Mason’s lilaeopsis) Methods Annual surveys conducted by foot during low tide between April and Since the mid-1900s, a series of over-bank flooding events CNPS List 1B.1 by the Napa River resulted in over $500 million of economic July. At each occurrence, we: • Diminutive, nondescript herbaceous perennial • Mapped with GPS damage. As a result, the Flood Protection Project was member of the Apiaceae family • Collected basic data (shown to left) initiated in 1964 by Napa County Flood Control and Water • Flowers April–October, fruits mature June–October • Entered into GIS to evaluate annual trends Conservation District along 6 miles of Napa River and 1.4 • Can spread rapidly by creeping rhizomes; water dis- miles of Napa Creek. Implementation began in 1999 and persal over greater distances likely The simple, turf-like life form of L. masonii, combined with its popula- included restoring riparian and floodplain ecosystems of the • Capable of self-fertilization (Affolter 1985); minute At each occurrence of tion biology, makes it extremely difficult to differentiate distinct ‘pop- Napa River to minimize future flood risks. black scavenger flies Ectaetia( sp.) may enhance ulations’ – population dynamics are best described by a ‘metapopu- pollination and seed set L. masonii we recorded: lation’. • Occurrences distinguished by a 50-ft break or habitat change Objectives of the 10-year rare plant monitoring are to: > Patch size • Length and width of each patch was recorded • Investigate effects of flood protection construction along (From Mathias and Constance 1977) > Phenology • Site quality based on non-native cover, stability of substrate, and Napa River During 2010, the team doc- observed threats • Mitigate for impacts to the rare Lilaeopsis masonii umented Ectaetia sp. visit- > Habitat • Threats included bank sloughing, sedimentation, trampling, goose ing L. masonii flowers and grazing, and encroaching vegetation • Track L. masonii occurrences and extent against collecting pollen. > Site quality Mitigation Targets > Threats

Lilaeopsis masonii (far left): Considered restrict- ed to inland brackish/ •• Metapopulation: A Population of Populations - Sources, Sinks, and Unoccupied Habitat freshwater habitats of the Golden Gate Estuary. Lil- •• Metapopulations are composed of relatively smaller ‘patch’ populations that establish and extinguish aeopsis occidentalis (near in what appears to be an unpredictable pattern. Large patches are not necessarily more important than left): Considered charac- smaller ones – location of a teristic of salt/brackish marshes of the Pacific particular patch may be as occupied Coast and larger/more important as patch size in robust than L. masonii unoccupied (maps taken from Hick- maintaining the metapopula- population boundary man 1993) tion. Both small and large migration/colonization patches serve as source pop- modified from Harrison 1991 In 2008, Fiedler et al. (2010) initiated a taxonomic genetic study to determine if L. ulations, which is particularly occidentalis and L. masonii should continue to be considered as two taxonomically true in fluvial systems such Field surveys were conducted during distinct units: as the Napa River. low tides when intertidal vegetation ••L. occidentalis and L. masonii are not distinct along Napa River river banks was ex- •• Small clods of soil with L. masonii that break from the river bank and disperse may be instrumental in posed. ••L. masonii should be subsumed under the widespread taxon L. occidentalis founding new populations within adjacent, nearby, or even relatively distant suitable habitat. ••These conclusions corroborated by field observations and overlap in geographic •• Populations at the river bank margin are not necessarily longer lived (nor more secure) than those distribution in this area closer to the high tide line.

Results Discussion A robust metapopulation persists; L. masonii flourished in Conservation recommendations for Lilaeopsis masonii were newly created habitat on restored floodplain, primarily within based upon a landscape-level approach to managing rare Literature Cited plant populations. Results indicate: Affolter, J. M. 1985. A monograph of the depositional areas with greater hydraulic complexity and slower genus Lilaeopsis (Umbelliferae). Sys- • velocities. Final 2010 monitoring documented: Lilaeopsis masonii has persisted and flourished in the tematic Botany Monographs, Vol. 6. • 28% increase in occurrences from 2009 Napa River 140 pp. 2 • Annual variability: No one-year is predictable from previous California Department of Fish and • Total area occupied of 8,963 ft , over double 2009 Game (CDFG). 2002. Memorandum • 74% increase in occurrences (2001-2010) years of Understanding by and between • Napa County Flood Control and Water • 13% increase in area occupied (2001-2010) Occurrences declined due to direct habitat loss from con- Conservation District and California • Never below mitigation targets two consecutive years struction; this was followed by reduced areal extent due Department of Fish and Game, June • Large inter-annual fluctuations; patches established/ to secondary effects of increased sediment, algal growth 2002. Reference number 1802-2002- due to an abundance of nitrogen from newly exposed sedi- 010-03. extinguished unpredictably Fiedler, P. L., E. K. Crumb, and A. K. ments, and wrack loads in the river Knox. 2010. Reconsideration of the • Recruits primarily within depositional areas of the flood- taxonomic status of Mason’s lilaeop- plain – in areas of greater hydraulic complexity and slower sis – a state-protected rare species in MITIGATION TARGETS (from CDFG 2002) California. October 2010; in revision. velocities In any two consecutive years, L. masonii populations should not fall below 10% of: Madroño. • Roughness features (e.g., large Scirpus sp. stands, large Harrison, S. 1991. Local extinction in a • 69 total occurrences metapopulation context: an empiri- 2 • Total area occupied ≥ 4,036 ft woody debris) facilitate founding of new populations by cal evaluation. Biol. J. Linnean Soc. providing habitat and/or lower velocity zones to settle out 42:73-88. 12,000 120 The majority (79%) of Lilaeopsis patches are between 0.25 and 4.0 ft2. Hickman, J., edition 1993. The Jepson 118 Over time, the most obvious population trend is the coalescence of smaller Manual. Higher Plants of California. 105 10,473 104 occurrences into larger ones. In 2010, 1% of patches observed (11 out of University of California Press, Berke- 2 ley, CA. Jepson Interchange: http:// 10,000 100 1,294) were over 150 ft . 92 ucjeps.berkeley.edu/interchange/I_ 8,963 . treat_indexes.html 8,246 Mathias, M.E. and L. Constance. 1977. 81 7,912 78 Two new local Umbelliferae from Cali- 8,000 80 fornia. Madroño 24: 78-83. 68 6,950 Acknowledgements 63 68 6,300 We would like to thank the following 65 6,000 60 people for their assistance and expertise related to this study: Doug Partridge, 5,489 5,600 Esa Crumb, Chris Grinter, Anthea Carmi- 5,007 chael, Erin Elsey, Nicole Jurjavcic, and 4,000 40 This shows the results of 2010 surveys in a portion of the Sebastian Araya. We also thank Sebas- Areal Extent (sq feet) Areal Extent

Number of Occurrences Project Area. Filled circles depict occurrences observed in tian Araya and Sapna Khandwala for 3,240 2010; open circles depict occurrences not observed in 2010; design assistance.

2,000 20 and, the color of the circle indicates the year the occurrence was first established. Finally, the merged lines depict the lin- ear extent of each occurrence as observed in 2010 - some New riprap is generally unsuitable Propagation and outplanting is 2 occurrences have grown from small, separate patches into habitat for Lilaeopsis, but after several difficult: In winter ‘04–05, 190 ft of 0 0 long linear stretches of uninterrupted L. masonii. years of twice daily inundation with transplanted material was installed. 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 Populations on small clods of concomitant sedimentation, suitable By 2010 only 1.8 ft2 remained. Documented areal extent (sq. ft.) Mitigation target (4,036 sq. ft.) soil that break from river bank habitat may form. At the end of the Inadequate securing led to large Documented occurrences Mitigation target (69) and disperse at high tide are ten-year study, riprap developed into losses by spring ‘05; inappropriate Trends of Lilaeopsis masonii occurrence and areal extent from 2001-2010 instrumental in founding new some marginally suitable habitat. scale and placement of logjams led to throughout the project area. populations. steady decline 2006–2010.