Native Functional Groups, Seeding Methods, and Maintenance Methods Determine Native Establishment in Trait-Based Restoration

Sarah Kimball, Megan Lulow, Quinn Sorenson

Functional Groups(species grouped by their traits)

Ruderals: early seral, colonizers, annuals, high relative growth rate

Perennials: late seral, competitors or stress tolerators, slower growth rate

Plant Traits and RestorationPlant Traits and Restoration

• Select plants based on traits (Select plants based on traits (Pywell et al. 03Pywell et al. 03))• Communities resistant to invasion contain Communities resistant to invasion contain

natives with traits similar to invasives natives with traits similar to invasives (limiting similarity hypothesis, (limiting similarity hypothesis, Emery 07Emery 07) )

• Plant natives with a range of traits and esp. Plant natives with a range of traits and esp. with traits similar to invasives (with traits similar to invasives (Funk et al. 08Funk et al. 08))

Research QuestionsResearch Questions

• What native functional group (ruderals, What native functional group (ruderals, perennials, or a mix) results in the best native perennials, or a mix) results in the best native establishment? establishment?

• Mechanics of restoration (Seeding Method? Weed Mechanics of restoration (Seeding Method? Weed removal methods?)removal methods?)

Grow and kill cycle:•Mow Nov 2009 •Spray Feb2010 •Mow June 2010•Spray Nov 2010•Seed Dec 2010

West Loma Ridge

Seed MixesSeed MixesDrill SeedingDrill Seeding Hand Seeding & TampingHand Seeding & Tamping

RuderalsRuderals PerennialsPerennials

Manual & MowingManual & Mowing Wick HerbicideWick Herbicide

Weed Removal TechniquesWeed Removal Techniques

Seeding MethodsSeeding Methods

Seed Mixes

Ruderals     Perennials    

Species  PLS lb/ac

Species  PLS lb/ac

Malacothrix saxatilis MASA 0.25 Artemesia californica ARCA 2Deinandra fasciculata DEFA 0.75 Eriogonum fasciculatum ERFA 3Calandrinia ciliata CACI 0.75 Encelia californica ENCA 3Phacelia cicutaria PHCI 2 Salvia apiana SAAP 2Eschscholzia californica ESCA 1 Lotus scoparius LOSC 3Lupinus succulentus LUSU 2 Leymus condensatus LECO 2Total   6.75 Total   15

Maintenance Treatments Every 4 weeks-standardized time/plot

1. Man/Mow: Hand Weeding (Manual) & weed-eating (Mow)

2. Wick: Herbicide-Wicking

First hand weeding, later weed eating to height of natives

Experimental DesignExperimental Design

6 replicates of all treatment 6 replicates of all treatment combinationscombinations

Data Collection & Analysis

Emergent Seedlings- One month post-seeding

Number of individuals- Late spring

Cover- Late spring (point intercepts)

Seed set & height - Summer

Mixed-model ANOVAs with block as a random factor and seeding method, maintenance treatment, and seed mix as fixed factors

Emergent Seedlings in Feb.Emergent Seedlings in Feb.

• Hand seeding resulted in greater emergence than drill seeding (FHand seeding resulted in greater emergence than drill seeding (F1,1021,102=24.03, =24.03, PP<0.0001).<0.0001).

• More perennial seedlings than ruderals (FMore perennial seedlings than ruderals (F1,1021,102=5.9, =5.9, PP=0.004). =0.004).

Emergent Seedlings: Emergent Seedlings: Seed MixesSeed Mixes

• • More perennials when seeded alone than in mixed group More perennials when seeded alone than in mixed group (F(F1,631,63=5.87, P=0.0183).=5.87, P=0.0183).

Emergent Emergent Non-NativeNon-Native Seedlings in Feb. Seedlings in Feb.

• Hand seeding resulted in greater germination of BRNI (FHand seeding resulted in greater germination of BRNI (F 1,971,97=55.37, =55.37, PP<0.001).<0.001).

• Drill seeding resulted in greater germination of invasive grasses (FDrill seeding resulted in greater germination of invasive grasses (F 1,971,97=11.58, =11.58, PP=0.01). =0.01).

Cover in Late Spring: Cover in Late Spring: Maintenance TechniquesMaintenance Techniques

• Wick was most effective at reducing non-nativesWick was most effective at reducing non-natives. .

• Native Cover increased with weed removalNative Cover increased with weed removal (F (F2,852,85=42.06, =42.06, PP<0.0001).<0.0001).

Late Spring Cover: Late Spring Cover: Seed MixesSeed Mixes

• Ruderals had greater overall cover during first growing seasonRuderals had greater overall cover during first growing season

• Each functional group had greater cover when planted alone (Perennials Each functional group had greater cover when planted alone (Perennials FF1,551,55=36.31, =36.31, PP<0.0001, Ruderals F<0.0001, Ruderals F1,551,55=10.38, =10.38, PP=0.002)=0.002)

Late Spring Late Spring DensityDensity: : Seed MixesSeed Mixes

• Perennials had greater overall Perennials had greater overall densitydensity during first growing season during first growing season

• Each group had greater density when planted alone (Perennials FEach group had greater density when planted alone (Perennials F1,551,55=29.67, =29.67,

P<0.0001, Ruderals FP<0.0001, Ruderals F1,601,60=8.62, P=0.005)=8.62, P=0.005)

Late Spring: Ordination of Plots in Species SpaceLate Spring: Ordination of Plots in Species Space

• Salvia apiana Salvia apiana correlated with axis 1 (r=0.962)correlated with axis 1 (r=0.962)

• Phacelia ciliata Phacelia ciliata negatively correlated with axis 1 (r=-0.72)negatively correlated with axis 1 (r=-0.72)

Native Species Seed Production

• Phacelia had reduced seed production when grown with perennials (F1,40=6.68, P=0.014)

• Malacothrix had reduced seed production when grown with perennials (F1,40=11.9, P=0.002).

Reproduction & Size of Perennials

• Eriogonum only reproduced in the wick treatment plots without ruderals.

• ERFA individuals were taller in plots without ruderals (F1,32=9.21, P=0.005).

• Lemus was larger in plots without ruderals (F1,23=4.63, P=0.04).

ConclusionsConclusions

• Each native functional group did best aloneEach native functional group did best alone

• Hand Seeding resulted in more native seedlings (and more BRNI)Hand Seeding resulted in more native seedlings (and more BRNI) • Wick herbicide removed more non-natives and resulted in higher Wick herbicide removed more non-natives and resulted in higher

reproduction of native species, but man/mow resulted in higher reproduction of native species, but man/mow resulted in higher cover and density of nativescover and density of natives

Implications for Trait-based RestorationImplications for Trait-based Restoration

• Importance of considering interactions among native Importance of considering interactions among native functional groups (not just between natives and functional groups (not just between natives and invasives) invasives)

• Contrary to coexistence theory, greater trait diversity Contrary to coexistence theory, greater trait diversity increased competitionincreased competition

• Seeding methods Seeding methods

Next StepsNext Steps

• Collecting data this year on germination in plots.Collecting data this year on germination in plots.• Return to marked perennials to measure Return to marked perennials to measure

survivorship, size, & fecundity survivorship, size, & fecundity • Seeded much larger area surrounding initial Seeded much larger area surrounding initial

experiment. experiment.

West Loma Restoration

Acknowledgements

Irvine Ranch Conservancy Staff: Isaac Oliva, Isaac Ostmann, Yi-Chin Fang

UCI CEB Faculty

UC Irvine student interns: Rosemary Garcia, Roxanne Murillo, Ashley Brutto

Funding: Orange County Parks, Donald Bren Foundation