The Big Three

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The Big Three
The Big Three
Contribution of invasive non-native species and flow
regime to changes in native riparian vegetation
Zarah Pattison, Dr Jeroen Mindermen & Dr Nigel Willby,
Twitter: @ZarahPattison University of Stirling
The Big Three
Invasive non-native, riparian heavyweights
Fallopia japonica,
Japanese knotweed
Impatiens glandulifera,
Himalayan balsam
Heracleum mantegazzianum,
giant hogweed
Riparian habitats are dynamic and highly vulnerable
to invasion
River flows and flood events are increasing
27%
in mean annual flow
flow (cumecs)
Average daily mean flows on R Teith since 1970
45
40
35
30
25
20
15
10
5
0
1965 1970 1975 1980 1985 1990 1995 2000 2005 2010 2015
What we know so far
• Evidence of invasives impacting native communities and seedbanks Gioria et al
2009, 2014
• Variations in river flows mobilize, transport and deposit sediment
• Links between sediment and seed deposition
Goodson et al. River Res. Applic. 2003
• Potential for fluvial disturbance & downstream transport of invasives has
increased = possible interactive effects!
OVERALL AIM
1) How do changes to flow regime impact
invasives
2) What is the consequence of these changes on
the native community
Expect:
flooding and deposition to
invasives
Invasives to
native diversity
turnover and
Methods: Seasonal veg surveys & germination trial
Existing dataset: long
term temporal & spatial
Regional scale: 20 rivers
Vegetation surveys along
river bank :
• Summer 2013
• Spring 2014
• Summer 2014
Germination trial using
soil cores and Astroturf
mats
Long-term, large scale effects of invasives
Predictor
High
Low
Dry
invasive % altitude & summer
Response cover
slope
Invasive
P/A
Native
diversity
Native
turnover
Increased
floods
Short-term, small scale effects of invasives
Predictor
Response
Invasive
seedlings
Native
seedlings
Seasonal
turnover
High
invasive %
cover
High
Sediment*
Sediment previous years
deposition invasives cover
The story continues….
Thank you
Dr Nigel Willby and the Freshwater
Detective Agency, University of Stirling
Dr Jeroen Minderman, St Andrews
University
Field Assistance
Robbie Whytock, University of Stirling
Dr Mario Vallejo-Marin, University of
Stirling
Professor Phil Boon, SNH
Email: [email protected]
Twitter: @ZarahPattison
1.0
0.8
0.6
0.4
0.2
0.0
Probability of invasive presence
Where are the invasives?
-4
High
-2
0
2
low altitude
0.7
11.6
22.5
33.3
40.9
Flood frequency
invasives along low altitude sites and when there is more flooding
Changes in native diversity
Survey1 Survey2
Shannon diversity
3
2
Survey1 Survey2
Invasives:
Native diversity
marginally
when invasives
present
Absent
Present
BC dissimilarity index
Summer 2013 V spring 2014 turnover
0
15
30
45
60
75
2013 invasive % cover
invasive cover and sediment = turnover
Cluster 1
Survey 1
Species
Agrostis stolonifera***
Myosotis scorpioides**
Epilobium spp ***
Persicaria hydropiper***
Equisetum arvense***
Juncus bufonius***
Callitriche stagnalis**
Deschampsia cespitosa***
Marchantia polymorpha***
Alopecurus geniculatus***
Juncus inflexus*
Hygrohypnum ochraceum***
Ranunculus sceleratus**
Rorippa amphibia**
Carex hirta***
Jungermannia spp. ***
Nardus stricta*
Survey 2
indicator_value
0.5908
0.5086
0.4137
0.375
0.2981
0.2887
0.2455
0.1829
0.1624
0.1623
0.1385
0.133
0.1271
0.1136
0.1116
0.0606
0.0455
Species
Salix spp.**
Sparganium erectum*
Impatiens glandulifera***
Leptodictyum riparium***
Stachys palustris***
Conocephalum conicum s.l.*
Angelica sylvestris***
Scrophularia auriculata**
Galium palustre***
Pellia epiphylla***
Lunularia cruciata**
Sagina procumbens***
Equisetum palustre***
Lysimachia vulgaris***
Callitriche platycarpa*
Cardamine amara***
Fallopia japonica***
Phragmites australis**
Brachythecium plumosum*
indicator_value
0.5429
0.4868
0.4192
0.3494
0.3377
0.3013
0.2599
0.2586
0.2292
0.2154
0.2046
0.2031
0.1714
0.1675
0.1591
0.1357
0.1288
0.0962
0.0649
Cluster 2
Survey 1
Survey 2
Species
indicator_value
Agrostis stolonifera*
0.4979
Rhynchostegium riparioides***
0.4288
Equisetum arvense*
0.2705
Chiloscyphus polyanthos*
0.2654
Eleocharis palustris***
0.2317
Alopecurus geniculatus***
0.2225
Fissidens spp.***
0.143
Scapania spp.*
0.1402
Pohlia melanodon***
0.1347
Cratoneuron filicinum**
0.1296
Carex acuta***
0.1227
Carex acutiformis**
0.1111
Glyceria notata**
0.0698
Species
Deschampsia cespitosa***
Persicaria hydropiper*
Filipendula ulmaria**
Galium palustre***
Pellia epiphylla***
Leptodictyum riparium***
Senecio aquaticus***
Sagina procumbens*
Stachys palustris***
Brachythecium rivulare*
Thamnobryum alopecurum*
Impatiens glandulifera***
Stellaria uliginosa**
Lunularia cruciata*
Montia fontana*
Rorippa sylvestris***
Fallopia japonica***
Epilobium brunnescens***
indicator_value
0.4182
0.3692
0.3659
0.3378
0.3319
0.3212
0.3069
0.26
0.24
0.2399
0.2214
0.2194
0.1634
0.1452
0.1343
0.1284
0.0935
0.0791

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