riparian restoration challenges: biocontrol and birds, genetics … · 2018. 4. 19. · riparian...
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Riparian restoration challenges: Biocontrol and birds, genetics-based
restoration strategies and an understudied non-native system
Sean M. Mahoney
Department of Biological Sciences, Northern Arizona University
April 9, 2018 Riparian Restoration & Tamarisk Beetle Workshop
Cochise College Benson Center
Changing landscape: How do native species respond?
Tamarisk Defoliated tamarisk
?
?
How do we restore riparian habitats?
Native-dominated
Defoliatedtamarisk
Other players in riparian systems
Russian olive Thorns!
Outline
• Tamarisk biological control
– How do birds respond to tamarisk biocontrol?
• Genetics-based approach to restoration
– How does cottonwood architecture affect tamarisk re-growth?
• Russian olive: “The new tammy”
– What are the bird communities in Russian olive-dominated habitat?
Study Area Virgin River
Mesquite, NV
Beaver Dam, AZ
Desert Springs, AZ
Gold Butte, NV
Big Bend, AZ
Gold butte
(2)
Mormon Mesa
(2)
Big
Bend
(2)
(2)
Native-dominated site (n=3) (~50-75% native)
Native-dominated site Tamarisk-dominated site (n=5)
(~75% tamarisk)
Biocontrol-affected site (n=3) (~90% dead tamarisk)
0
0.1
0.2
0.3
0 0.25 0.5 0.75 1
Enh
ance
d v
eget
atio
n in
dex
(EV
I)
% Biocontrol-affected tamarisk
R2 = 0.56, p = 0.007 (2013/2014)
Decreases in “greenness”
Temperature/humidity decreases
20
25
30
35
25
27
29
0.1 0.3 0.5 0.7 0.9
Rel
ativ
e h
um
idit
y (%
)
Tem
per
atu
re (
°C)
% Biocontrol-affected tamarisk
Temperature: R2 = 0.75, p = 0.007
Relative humidity: R2 = 0.67, p = 0.01
How do birds respond to tamarisk-biocontrol?
• 2 visits in 2013 and 2014 each
• 6 points per site
• 0500-1100, low wind, no rain
• estimated % tamarisk biocontrol-affected
• quantified community assemblages based on presence/absence
• calculated species richness
• modeled bird densities in Distance package (R)
Community assemblages differed overall
-0.1
0
0.1
0.2
-0.1 0 0.1 0.2
NM
DS2
NMDS1
Overall PERMANOVA: p < 0.0001
Native
Dead tam
Live tam
Species richness declines
0
10
20
30
0 0.25 0.5 0.75 1
Mea
n s
pec
ies
rich
nes
s
Biocontrol-affected tamarisk (%)
R2 = 0.41, p < 0.02
Complex responses to biocontrol
0
1
2
3
0 0.25 0.5 0.75 1
Bir
ds/
ha
R2 = 0.65 p < 0.005
0
1
2
3
0 0.25 0.5 0.75 1
R2 = 0.58 p = 0.01
0
1
2
3
0 0.25 0.5 0.75 1% Tamarisk biocontrol-affected
R2 = 0.05 p > 0.5
0
1
2
3
0 0.25 0.5 0.75 1
Bir
ds/
ha
% Tamarisk biocontrol-affected
R2 = 0.05 p > 0.5
% Tamarisk biocontrol-affected
% Tamarisk biocontrol-affected
Birds like weevils, hate beetles
Available Diet
Weevil TLB Larvae L.
hopper Other
Mahoney et al. 2017 Biological
Inv.
Rel
ativ
e av
aila
bili
ty
Management implications
• Birds respond differently to biocontrol
• Nesting behavior may be an effective way predict bird response to biocontrol –Caution: densities do not assess habitat
quality (productivity, food, etc.)
• Stress the need for restoration –Minimize loss of habitat for native species
Part 2: Genetics-based restoration
US Forest Service
Part 2: Genetics-based restoration
2 challenges in restoration
• How do we deal with interspecific competition between native and non-natives? (Sher et al. 2002, Dewine and Cooper 2008) – Architecture is genetics-based (Bailey et al. 2011) – Interaction between native architecture and tamarisk
architecture is not well understood (especially in relatively older trees)
• How do we deal with changing climates? (Tom Whitham’s NAU cottonwood group) – “Genes that are adaptive today and maladapted for
tomorrow”
• So what’s the best stock to select from given these two challenges?
How does cottonwood architecture affect tamarisk re-growth?
• Chevelon Creek common garden/restoration project, Winslow AZ
• Collected and planted cottonwoods from broad elevational/latitudinal/temperature ranges
• 3 years old • Measured: cottonwood
height, canopy width, basal area, stems
• Measured: understory tamarisk height, stems
Mahoney et al. in revision Restoration Ecology
Cottonwoods exhibit different architecture
PERMANOVA: p < 0.001
Mahoney et al. in revision Restoration Ecology
Source population
within 3°C from Chevelon
0
100
200
300
400C
ott
on
wo
od
hei
ght
(cm
)
0
100
200
300
NCC OV SP AL ML
Co
tto
nw
oo
d w
idth
(cm
)
0
25
50
75
Co
tto
nw
oo
d b
asal
are
a (c
m2)
0
2
4
6
8
NCC OV SP AL ML
Co
tto
nw
oo
d s
tem
s
a a
b,c b
c
b b
b
b
a
a
b
c b,c
c
a
a,b b
b,c c
Height Basal Area
Canopy Width Stems
Source pop. Source pop.
Cottonwood architecture affects tamarisk re-growth R2 = 0.27, p < 0.001 R2 = 0.21, p = 0.003
R2 = 0.14, p = 0.02 R2 = 0.2, p = 0.004
Tam
aris
k H
T Ta
mar
isk
stem
s
Cottonwood HT Cottonwood canopy Mahoney et al. in revision Rest. Ecol.
Part 2 Conclusions
• Cottonwood architecture differed by source population at Chevelon Creek
• Cottonwood architecture negatively affected understory tamarisk re-growth – Possibly driven by response to frost
• Therefore, selecting proper cottonwood genotypes are critical for restoration success – Local stock may be best for short-term gains
– Stock within 3°C best for long-term gains
• Introduced in late 1800s (Christiansen 1963).
• Native to Europe and Asia (Little 1961).
• Occurs in riparian areas (Fischer et al. 2012).
• May be replacing native riparian vegetation (Currier 1982).
• 4th most dominant woody plant species in western US riparian areas (Friedman et al. 2005).
• Conservation implications: Riparian habitat is important for birds, mammals, and herps (Finch and Ruggiero 1993).
• Biocontrol agent has been identified and trials are being conducted to test efficacy
Russian olive
Part 3: Russian olive: “The new tammy”
Study sites • Sites varied in amount of Russian olive.
– RO site = ≥75% Russian olive cover/≤25% native cover. – Native site = ≥50% native cover/≤50% Russian olive cover.
• Tamarisk was also present at all sites, but not dominate cover type.
Mixed site (n=10) Russian olive site (n=20)
Presence/Absence surveys
• Conducted bird presence/absence surveys in May, June, July, August
• Presence=Any bird seen or heard by at least one observer
Peter J. Motyka
Willow flycatcher
Peter J. Motyka
Bullock’s oriole
Species richness similar among Russian olive- and native-dominated sites
Number of sites
Rar
efie
d S
pec
ies
rich
nes
s (±
95
% C
I)
Native Russian olive
Mahoney et al. in revision J. Arid Environs
Russian olive-dominated habitats support similar bird communities as native-dominated
PERMANOVA: p = 0.2 Dispersion: p = 0.1
Native Russian olive
Mahoney et al. in revision J. Arid Environs
Russian-olive dominated habitats support similar distribution of foraging
guilds to native-dominated
0
0.25
0.5
0.75
Insectivore Granivore Generalist Driller Frugivore
Perc
en
tage
Dis
trib
uti
on
Native Russian olive
K-S Goodness of Fit test: D = 0.4, p = 0.8
Mahoney et al. in revision J. Arid Environs
Part 3 Conclusions
• Russian olive may provide habitat and food for native species (Olson and Knopf 1986, Fischer et al. 2012).
• Like tamarisk, Russian olive biocontrol may progress faster than restoration – removing habitat and food.
• Russian olive control must be coupled with restoration (Bateman and Paxton 2010).
Final considerations
• Riparian areas are undergoing many changes – Biological control
– Multiple non-native species
• Our understanding of the ecology of some players is not well known
• Effective management should consider response of native species as well as the interaction between genetics and the environment
Acknowledgements • Part 1
– Matthew J. Johnson (NAU CPRS)
– Jennifer A. Holmes (NAU CPRS)
• Part 2
– Jesse B. Mike (NAU SOF)
– Jackie L. Parker (NAU BIO)
– Linda S. Lassiter (NAU BIO)
– Thomas G. Whitham (NAU BIO)
• Part 3
– Anna Nellis B. Smith (CPRS NAU)
– Peter J. Motyka (NAU BIO)
– Erick Lundgren (UT Sydney, AUS)
– Matthew J. Johnson (NAU CPRS)
– Raemy R. Winton (NAU CPRS)
– Bo Stevens (NAU BIO)
Yellow-breasted chat maintains densities after biocontrol
0
0.1
0.2
0.3
0
1
2
3
0 0.25 0.5 0.75 1
Enh
ance
d V
eget
atio
n In
dex
(EV
I)
Bir
d d
ensi
ty (
bir
ds/
Ha)
% Tamarisk cover
R2 = 0.21, p = 0.17