This is Japanese Knotweed in winter on the Dochart.
INVASIVE SPECIES IN THE TAY WESTERN CATCHMENTS AREA
Summary
During our survey work, the opportunity was taken to record information on invasive species, concentrating initially on the three highest profile invasives on Tayside; Japanese knotweed, Himalayam Balsam and giant hogweed. A 2006 survey by the Tay District Salmon Fisheries Board suggested only one record in the three glens, as did a survey by SNH a few years beforehand. We were potentially in a position to gather more comprehensive information on invasive species as we were targeting minor tributaries as well as the main rivers, and invasive species often establish themselves from gardens set back from the main rivers in catchments, and travelling along these minor watercourses. We could therefore give an early warning of potential hidden sources.
The occurrence of such species in these catchments is indeed very low.
During the survey we located seven areas of Japanese knotweed (1000 sq metres max) and two concentrations of himalayam balsam (< 100 sq m total). There is no Giant Hogweed in this area.
Rhododendrons were found in 21 main locations. They were not easily correlated with watercourses as such, and therefore no overall quantity can be given. However, we have tried to identify the priority locations.
An additional invasive species, white butterbur, is present in the lower part of Glenlyon, found at 17 locations (400 sq m). A much larger (but unmapped) area of this species occurs along the roadsides in lower Glenlyon, with smaller concentrations also apparently present within Killin, but unassociated with the rivers.
Three other records were made of potentially invasive garden plants totalling c 300 sq m.
Finally, signs of mink were found throughout each of the three glens, the importance of this being documented elsewhere. There will also be a section on non-native tree species, with particularly good information on the spread of sycamore and beech within riparian habitats in the area. On the Dochart, it appears that small areas of grey alders, seemingly originating from Tyndrum, are spreading by natural regeneration, and it may be appropriate to also treat these as an “invasive” species.
Limitations of data
Overall, we believe this data to be very good, the overall survey protocol and potential outputs justified us searching along very minor watercourses set back from the main rivers. In addition, in summer 2008, the main stems of the Fillan/ Dochart and the Lyon were searched again for a second time using a pair of canoes, specifically just looking for other records of invasive species. The records of the three main invasives are therefore likely to be fairly accurate.
White butterbur is concentrated mostly along roadsides, and therefore the greater area of this species, potentially several thousand square metres, will not have been picked up by our survey.
Finally, while the main invasives were closely associated with watercourses, rhododendrons showed no such correlation, and our survey protocol did not warrant the additional time that would be required to accurately measure their distribution. Our survey therefore only recorded those concentrations intersected by watercourses. Rhododendrons are not regarded as being as invasive on Tayside as on the west coast (FCS pers comm.) and do not seem to spread with the same alarming speed here.
It is anticipated that other potentially invasive species may be present in these catchments, in and around the main areas of settlements. Surveyors did not have the necessary botanical skills to recognize the full range of potentially invasive species, nor did our protocol allow for much time to be spent on this aspect of the survey work.
Use for the Information Gathered
We anticipate that given the low levels of invasive species present in these three glens, that it should be possible to eradicate them within the next few years before they become a more significant issue.
The angling clubs in the three glens are well placed for them to monitor the catchments for any subsequent incursions, and it is one of our priority recommendations that their capacity to deliver this function be properly developed and supported.
Accessing the Information
The information gathered on invasive species has been passed to FCS on Tayside who employ a project officer who is to specialize in invasive species, and to the LLTNPA.
Summary
During our survey work, the opportunity was taken to record information on invasive species, concentrating initially on the three highest profile invasives on Tayside; Japanese knotweed, Himalayam Balsam and giant hogweed. A 2006 survey by the Tay District Salmon Fisheries Board suggested only one record in the three glens, as did a survey by SNH a few years beforehand. We were potentially in a position to gather more comprehensive information on invasive species as we were targeting minor tributaries as well as the main rivers, and invasive species often establish themselves from gardens set back from the main rivers in catchments, and travelling along these minor watercourses. We could therefore give an early warning of potential hidden sources.
The occurrence of such species in these catchments is indeed very low.
During the survey we located seven areas of Japanese knotweed (1000 sq metres max) and two concentrations of himalayam balsam (< 100 sq m total). There is no Giant Hogweed in this area.
Rhododendrons were found in 21 main locations. They were not easily correlated with watercourses as such, and therefore no overall quantity can be given. However, we have tried to identify the priority locations.
An additional invasive species, white butterbur, is present in the lower part of Glenlyon, found at 17 locations (400 sq m). A much larger (but unmapped) area of this species occurs along the roadsides in lower Glenlyon, with smaller concentrations also apparently present within Killin, but unassociated with the rivers.
Three other records were made of potentially invasive garden plants totalling c 300 sq m.
Finally, signs of mink were found throughout each of the three glens, the importance of this being documented elsewhere. There will also be a section on non-native tree species, with particularly good information on the spread of sycamore and beech within riparian habitats in the area. On the Dochart, it appears that small areas of grey alders, seemingly originating from Tyndrum, are spreading by natural regeneration, and it may be appropriate to also treat these as an “invasive” species.
Limitations of data
Overall, we believe this data to be very good, the overall survey protocol and potential outputs justified us searching along very minor watercourses set back from the main rivers. In addition, in summer 2008, the main stems of the Fillan/ Dochart and the Lyon were searched again for a second time using a pair of canoes, specifically just looking for other records of invasive species. The records of the three main invasives are therefore likely to be fairly accurate.
White butterbur is concentrated mostly along roadsides, and therefore the greater area of this species, potentially several thousand square metres, will not have been picked up by our survey.
Finally, while the main invasives were closely associated with watercourses, rhododendrons showed no such correlation, and our survey protocol did not warrant the additional time that would be required to accurately measure their distribution. Our survey therefore only recorded those concentrations intersected by watercourses. Rhododendrons are not regarded as being as invasive on Tayside as on the west coast (FCS pers comm.) and do not seem to spread with the same alarming speed here.
It is anticipated that other potentially invasive species may be present in these catchments, in and around the main areas of settlements. Surveyors did not have the necessary botanical skills to recognize the full range of potentially invasive species, nor did our protocol allow for much time to be spent on this aspect of the survey work.
Use for the Information Gathered
We anticipate that given the low levels of invasive species present in these three glens, that it should be possible to eradicate them within the next few years before they become a more significant issue.
The angling clubs in the three glens are well placed for them to monitor the catchments for any subsequent incursions, and it is one of our priority recommendations that their capacity to deliver this function be properly developed and supported.
Accessing the Information
The information gathered on invasive species has been passed to FCS on Tayside who employ a project officer who is to specialize in invasive species, and to the LLTNPA.
3 comments:
I work for a weed control company based in Scotland. We do a lot of weed treatment work on the banks of major watercourses. If you require any advice regarding removal of invasive weeds then please let me know, I'd be more than happy to help.
Drop me a message on victor.clements@scottishnativewoods.org.uk so that I have your contact details on record.
Thanks.
VC
Thanks.
Email sent.
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