Predispersal seed predation of Wyethia amplexicaule, Crepis acuminata, and Agoseris glauca
Robert L. Johnson and Val Jo Anderson Brigham Young University
project
• Document seed predation in select forb species • Document occurrence of pest parasitoids • Effect of treatment with imidacloprid methods
• 3 plant populations • 20 plants – nearest plant to point on transect bisecting population • 5 random plants per imidacloprid treatment – soil drench – spray – control • Seed heads harvested following anthesis and reared in the lab • Following insect emergence, individual seed were examined for damage
Imidacloprid treatment
Soil drench: 0.5 gallons solution = 1.2 grams active ingredient
Spray: foliar spray until solution begins dripping from foliage
Wyethia amplexicaulis
Reared capitula 2,256 Neotephritis finalis 2256 Trupanea nigricornis 186 Melanagromyza sp. 15 Lepidoptera 24 Seed damage
average=39.0% 60
40 # samples # samples
20
0
e 0% 5% 0% 0% or 1 15% 20% 25% 30% 35% 40% 45% 50% 55% 60% 65% 70% 75% 8 85% 90% 95% M % seed damage Agoseris glauca
Reared capitula 575 Campiglossa sp. 155 Diptera (unknown) 18 Seed damage
600
500
400
average=8.1
300 # samples 200
100
0 0% 1-20% 21-40% 41-60% 61-80% 81-99% More % seed damage Imidacloprid treatment: site x treatment (p<0.01)
18.0% b 16.0%
14.0%
12.0%
10.0%
8.0% a a 6.0% a
percent seed damage 4.0% a a 2.0% a a a 0.0% Manti Ridge Teat Mountain Willow Creek habitat
control spray drench Crepis acuminata
Reared capitula: 2859 Campiglossa sp 52 Phycitodes albatella 133 subsp. mucidella
Seed damage
220
200
180
160 average=12.4% 140
120
100
# samples 80
60
40
20
0 0% 1-20% 21-40% 41-60% 61-80% More % seed damage Imidacloprid treatment: habitat x site x year (p<0.01)
10.0%
9.0%
8.0%
7.0%
6.0%
5.0%
4.0%
percent seed damage 3.0%
2.0%
1.0%
0.0% Squaw Peak Sheep Creek West Mountain Squaw Peak Sheep Creek West Mountain
2006 2007
control spray drench conclusions
• Significant seed damage can occur in wild plant populations – Year and site influence percent damage • A new seed predator, host associations, and parasitoids were discovered • Capitulum size of W. amplexicaulis influences pest abundance per capitulum but not total percent seed damage • Imidacloprid treatment can reduce seed damage – soil drench provides greater pest control but was not significant most of the time at the 95% confidence level. Impact of Habitat Alterations to Bee Diversity in Sagebrush and Pinyon/Juniper Communities of the Eastern Great Basin
Robert L. Johnson and Val Jo Anderson Brigham Young University
project
Hypothesis: introduced grassland habitats support lower bee diversity than neighboring native habitats
• quantify the differences/similarities in bee diversity between natural and altered habitats – 3 sites x 4 habitats x 3 traps per = 36 traps – Malaise traps – Continuous sampling – two week intervals • quantify vegetation in each habitat – flowering plant density – plant cover sagebrush pinyon/juniper cheatgrass crested wheatgrass Results
• 162 taxa • 44 singletons • 21 doubletons – 40.1 % rare Bee abundance – site x year (p=0.04)
100.0 b
90.0
80.0
70.0
60.0 ab 50.0 aa 40.0 a a 30.0
average bee abundance/trap 20.0
10.0
0.0 Antelope Valley Tintic Valley Yuba site
2006 2007 Bee abundance by habitat (p<0.01)
120 c 100
80
60
40 a a 20 average bee abundance per trap b
0 cheatgrass crested wheatgrass juniper sagebrush habitat Bee richness by habitat (p<0.01)
35 c
30
25
20
a 15 a
10 b
average bee bee richness per trap 5
0 cheatgrass crested wheatgrass juniper sagebrush habitat 3D MDS of bee diversity by habitat
Transform: Log(X+1) Resemblance: S17 Bray Curtis similarity 3D Stress: 0.19 Habitat Cheatgrass Crested Juniper Sagebrush Prevalent and modal bee species
Cheatgrass modal habitat bee species % frequency rank species specific Lasioglossum (Dialictus) hyalinum 88.9% 1 x Lasioglossum (Lasioglossum) sisymbrii 83.3% 2 x Lasioglossum (Dialictus) incompletum 77.8% 3 x Eucera actuosa Cresson 1878 50.0% 4 Lasioglossum (Dialictus) albohirtum 50.0% 5 x x Lasioglossum (Dialictus) sed i 50.0% 6 Eucera lutziana (Cockerell) 1933 44.4% 7 Agapostemon angelicus Cockerell 1924 38.9% 8 x x Lasioglossum (Dialictus) pruinosiforme 38.9% 9 x x Lasioglossum (Evylaeus) pulveris 38.9% 10 x Lasioglossum (Dialictus) sp. 33.3% 11 Melissodes sp. 33.3% 12 Anthophora urbana Cresson 1878 27.8% 13 Lasioglossum (Dialictus) sp. 19 27.8% 14 Lasioglossum (Evylaeus) incompletum 27.8% 15 Perdita albonotata Timberlake 1954 27.8% 16 x x
Sagebrush modal habitat bee species % frequency rank species specific Eucera actuosa Cresson, 1878 55.6% 1 Eucera lutziana (Cockerell, 1933) 55.6% 2 Osmia sp. 55.6% 3 Lasioglossum (Dialictus) sp. K1 44.4% 4 Lasioglossum (Dialictus) hyalinum 38.9% 5 Lasioglossum (Lasioglossum) sisymbrii 38.9% 6 Eucera fulvitarsis Cresson, 1878 33.3% 7 Lasioglossum (Dialictus) sp. 33.3% 8 Andrena piperi Viereck, 1904 27.8% 9 x x Anthophora ursina Cresson, 1869 27.8% 10 Lasioglossum (Dialictus) sedi 27.8% 11 45 40 40
35
30 28
25 21 20 # species#
15 11 9 9 9 10 8 77
5 1 0 0 cheatgrass crested wheatgrass juniper sagebrush habitat
singletons habitat specific modal Plant richness – habitat x site (p=0.04)
14
12
10
8
6
4
2
0 Antelope Valley Tintic Valley Yuba site x habitat interaction
cheatgrass crested w heatgrass juniper sagebrush 3D MDS of flowering plant diversity by habitat
Transform: Log(X+1) Resemblance: S17 Bray Curtis similarity 3D Stress: 0.13 Habitat type Cheatgrass Crested Juniper Sagebrush Herbaceous cover
30%
25%
20%
15% % cover
10%
5%
0% Cheatgrass Crested wheatgrass Sagebrush Juniper habitat
3.5
Bee and 3 flowering plant 2.5 phenology 2
1.5 log10(x+1)
1
0.5
0
y l t a ct Apr Jul Oc M Jun Ju Aug Aug 4 8 5 Jun 3 4 8 9 O 3 abundance 2 22 May 19 17 31 Jul 1 2 11 Sep 25 Sep 2 total bee abundance mean flowering plants/hectare2
90
80
70
60
50
40 # species
30
20
10
0
l ay u ul Jun J Jul M Jun J Aug Aug Sep Sep 8 May 5 9 3 7 1 4 8 1 5 9 Oct 24 Apr 22 1 1 3 1 2 1 2 23 Oct
richness bee richness plant richness Conclusions
1. Bee diversity is influenced by habitat, site, and year 2. A strong relationship exists between flowering plant diversity and bee diversity 3. Pinyon/juniper habitat generally supports the greatest flowering plant and bee diversity 4. Crested wheatgrass supports the lowest bee abundance and diversity 5. Mature pinyon/juniper stands have high conservation value for bee populations 6. Metrics for restoration success should factor in forb abundance