Grevillea at Pine Island to Point Hut
Identification history
| Grevillea juniperina | 23 Jul 2018 | MichaelMulvaney | ||
| Grevillea juniperina | 23 Jul 2018 | michaelb |
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Significant sighting
michaelb noted:
24 Jul 2018
The number of these plants has increased from just a few 20 years ago to an alarming number of over 1000 at the moment. It is crowding out the smaller native shrubs and forbs. It can grow to up to three metres tall and the foliage is quite dense. It is significant because up to now the species has not been regarded as invasive. Also see comments.
User's notes
Abundant on the east side of the Murrumbidgee River, from well south of Pine Island right thru the Pine Island main area and extending well to the north also.
14 comments
michaelb
wrote:
23 Jul 2018
These photos were taken to show how dense the spread of this weedy species is along the river south of Pine Island. To the north of Pine Island is a similar spread. The small shrubs in the foreground are Leucopogon attenuatus and are being crowded out by the much larger grevillea.
I wish to emphasise that this sighting shows only a small portion of the extent of the population of this Grevillea explosion. It extends further to the south several hundred metres and to the north up through Pine Island and way beyond that to the north. It has a range of at about three kilometres that I know of with several thousand plants.
I wish to emphasise that this sighting shows only a small portion of the extent of the population of this Grevillea explosion. It extends further to the south several hundred metres and to the north up through Pine Island and way beyond that to the north. It has a range of at about three kilometres that I know of with several thousand plants.
michaelb
wrote:
16 Aug 2018
While this sighting has been identified as Grevillea juniperina, it is not 100% accurate. The primary resemblance is to that species, but there is evidence of hybridising with other species including G. rosmarinifolia and G. lanigera. This has been verified by Rainer Rehwinkel, who describes the population as a "'hybrid swarm', showing the characteristic 'hybrid vigour'". While this sighting is to the south of Pine Island, note that the population extends to the north of Pine Island as well, covering quite a large area.
michaelb
wrote:
16 Aug 2018
See Rainer Rehwinkel's FaceBook post which he recorded after I showed him to the site on 14 August 2018:
https://www.facebook.com/100004693938376/posts/1112998632199924/?comment_id=1113016548864799
https://www.facebook.com/100004693938376/posts/1112998632199924/?comment_id=1113016548864799
rainer
wrote:
16 Aug 2018
An article about this will appear in the next FOG newsletter. My Facebook post on the subject garnered many many well-informed comments. A general feeling of agreement has arisen and this is that the grevilleas should all be removed from this site. If resources for that are not available, then those populations impacting on the grassland (community r8) with the high density of Small-leaved Beard-heath (Leucopogon attenuatus) should be targeted as a priority.
michaelb
wrote:
16 Aug 2018
Thanks Rainer. It is very good of you to bring this to public attention. The plant community to the north of Pine Island is different and may be worth checking out at a later date.
MichaelMulvaney
wrote:
17 Aug 2018
I sent these links to Darren Roso the ranger responsible for this area who replied
"‘just had a read. This is good work
Not quite as simple as that. The population explosion is a response to our rabbit control. True we do have hybrids there.
All the G.rosmanifolia X juniperinum “Canberra gem” can now go. There aren’t very many now. We have controlled the vast majority. That’s how we are aware of the hybrids. No one could tell us what they are hybrids of and they never seeded so we /I don’t attach any urgency.
But the G. lanigera X G. juniperinum are probably natural. And I argue tolerable. Simply a symptom of the massive population reduction during the sheep and rabbit years.
The G.rosmanifolia X juniperinum “Canberra gem” planted in the 80’s during the forward plantings are a problem and the amount to which they have expressed in the genetics…………..really hard to judge. As I mention above, they can go now that the Lanigera and juniperinum has recovered.
The G. juniperinum and lanigera are so important for our birds, since they bridge the Winter nectar gap, and are good nesting/refuge sites, that I propose a very careful removal program if at all. The suite of avi fauna of the Murrumbidgee is a remarkable thing and we should only very carefully manage habitat.
Control is not a big job. We are talking a 000 plants. Cut and dab with Glyphosate only. The vegetation here is very interesting and poorly known. And even more poorly understood.
Let me go have another look this week end………………….
cheers
Darren Roso
Senior Ranger - Murrumbidgee
"‘just had a read. This is good work
Not quite as simple as that. The population explosion is a response to our rabbit control. True we do have hybrids there.
All the G.rosmanifolia X juniperinum “Canberra gem” can now go. There aren’t very many now. We have controlled the vast majority. That’s how we are aware of the hybrids. No one could tell us what they are hybrids of and they never seeded so we /I don’t attach any urgency.
But the G. lanigera X G. juniperinum are probably natural. And I argue tolerable. Simply a symptom of the massive population reduction during the sheep and rabbit years.
The G.rosmanifolia X juniperinum “Canberra gem” planted in the 80’s during the forward plantings are a problem and the amount to which they have expressed in the genetics…………..really hard to judge. As I mention above, they can go now that the Lanigera and juniperinum has recovered.
The G. juniperinum and lanigera are so important for our birds, since they bridge the Winter nectar gap, and are good nesting/refuge sites, that I propose a very careful removal program if at all. The suite of avi fauna of the Murrumbidgee is a remarkable thing and we should only very carefully manage habitat.
Control is not a big job. We are talking a 000 plants. Cut and dab with Glyphosate only. The vegetation here is very interesting and poorly known. And even more poorly understood.
Let me go have another look this week end………………….
cheers
Darren Roso
Senior Ranger - Murrumbidgee
michaelb
wrote:
19 Aug 2018
A comment by Steve Taylor posted on FaceBook:
"Some quotes from #InvasionDynamics regarding the impacts of hybridisation initiated by alien or non-local species: "Hybridisation initiated by alien species invasions provides some of the most unambiguous cases of rapid evolutionary diversification." "Results of any of these hybridisation events can include the formation of new species, introgression of genetic material into one or both of original species, or the formation of hybrid swarms, depending on the genetics and ecology of the two species." These impacts are hard to manage for urban reserves surrounding by suburbs planted with a wide range of non-local natives. But it can be managed more easily in Namadgi NP - there is a new project that is checking all the plantings at the tracking stations and huts. Non-local Grevilleas have started to be removed along with known invasive plants like Oregon grape and English ivy. Any species that can be classed as a "transformer" has the highest priority for removal or control. See this article for definitions:
https://drive.google.com/open?id=1fjW4UwsXzEiOzkjhE29QYcwRGJVO8R4T ".
"Some quotes from #InvasionDynamics regarding the impacts of hybridisation initiated by alien or non-local species: "Hybridisation initiated by alien species invasions provides some of the most unambiguous cases of rapid evolutionary diversification." "Results of any of these hybridisation events can include the formation of new species, introgression of genetic material into one or both of original species, or the formation of hybrid swarms, depending on the genetics and ecology of the two species." These impacts are hard to manage for urban reserves surrounding by suburbs planted with a wide range of non-local natives. But it can be managed more easily in Namadgi NP - there is a new project that is checking all the plantings at the tracking stations and huts. Non-local Grevilleas have started to be removed along with known invasive plants like Oregon grape and English ivy. Any species that can be classed as a "transformer" has the highest priority for removal or control. See this article for definitions:
https://drive.google.com/open?id=1fjW4UwsXzEiOzkjhE29QYcwRGJVO8R4T ".
rainer
wrote:
19 Aug 2018
After much debate on FB, it’s still not clear what is to be done with these grevilleas. As Darren Ruso argues, the grevilleas appear to be an important nectar resource, however the issue is that that population at Pine Island is most probably much larger than the original local population of G. juniperina is likely to have been and the plants here are pretty much all along a continuum of hybridisation, from almost pure G. juniperina, to plants all-but indistinguishable from G. rosmarinifolia. In addition, there are genes from G. lanigera, there, and as Darren mentions, from G. “Canberra Gem”, which is itself a hybrid of juniperina and rosmarinifolia. So what we have is the classic hybrid swarm, showing the classic hybrid vigour, and it is most likely this that is causing the population explosion and the resulting invasion into the native systems here, at least one of which is a CEEC (NTG SEH). The added boon for local populations of honeyeaters and other small passerines that may be using this site need to be carefully weighed up with the likely dis-benefits, especially the risk of the spread of genes from the hybrid swarm into more intact populations of both juniperina and lanigera, as I understand it, both upstream and downstream from this site. Ian Fraser, in his comment on my FB post was unequivocal - to paraphrase, no argument, get rid of them all!
michaelb
wrote:
21 Aug 2018
Following is the full text of Rainer Rehwinkel's post on Facebook on 14 August and later edits.
Note that the text is too long to fit in the required space and will need 4 comments,
Nature Notes from the Murrumbidgee, 14 August,... - Rainer Rehwinkel
Today, I joined some Friends of Grasslands, Margaret Ning, Michael Bedingfield and Dave Mallinson, on an inspection of some potentially “feral” grevilleas in the gorge of the river near the suburb of Bonython. Michael had recorded this population in Canberra’s NatureMap app, but was uncertain of the identity of the plants. Apparently, there had been a planting of Juniper Grevilleas (Grevillea juniperina) at the site many years before, but since the site had suffered damage from a bushfire some years ago, a new much larger population has emerged, and it appears, from our inspection, that plants with hybrid parentage are present.
A major issues here is that large groves of grevilleas are encroaching on, and threatening the integrity of, a significant plant community growing on some rocky knolls. That community, possibly allied to, or even part of the grassland community that grows in steep rocky sites in our region (community r8), is here augmented by a population of the Small-leaved Beard-Heath (Leucopogon attenuatus), which today were seen flowering beautifully. Also present were plants of Barbed-wire Grass (Cymbopogon refractus), a grass allied to the culinary Lemongrass, and an indicator species of Community r8).
Continued below....
Note that the text is too long to fit in the required space and will need 4 comments,
Nature Notes from the Murrumbidgee, 14 August,... - Rainer Rehwinkel
Today, I joined some Friends of Grasslands, Margaret Ning, Michael Bedingfield and Dave Mallinson, on an inspection of some potentially “feral” grevilleas in the gorge of the river near the suburb of Bonython. Michael had recorded this population in Canberra’s NatureMap app, but was uncertain of the identity of the plants. Apparently, there had been a planting of Juniper Grevilleas (Grevillea juniperina) at the site many years before, but since the site had suffered damage from a bushfire some years ago, a new much larger population has emerged, and it appears, from our inspection, that plants with hybrid parentage are present.
A major issues here is that large groves of grevilleas are encroaching on, and threatening the integrity of, a significant plant community growing on some rocky knolls. That community, possibly allied to, or even part of the grassland community that grows in steep rocky sites in our region (community r8), is here augmented by a population of the Small-leaved Beard-Heath (Leucopogon attenuatus), which today were seen flowering beautifully. Also present were plants of Barbed-wire Grass (Cymbopogon refractus), a grass allied to the culinary Lemongrass, and an indicator species of Community r8).
Continued below....
michaelb
wrote:
21 Aug 2018
Continued from above (Rainer Rehwinkel on FaceBook)....
Close inspection of the grevilleas here revealed resemblances of some of them to commonly planted garden species, including the Rosemary Grevillea (G. rosmarinifolia) and Woolly Grevillea (G. lanigera). We questioned too, whether the original plantings of G. juniperina, which by the way has natural populations in the ACT, including upriver from this site, were indeed here of the local provenance plants. Margaret pointed out that this widespread species has, according to PlantNet, no fewer than nine subspecies. The species has long been in the nursery trade, and those original plantings here at the Murrumbidgee may very easily have been sourced from nursery plants from anywhere within the species’ range.
Here then, we have a typical situation where a new population has emerged, with genes infused from nearby garden plantings of clearly non-locally indigenous species, and into plants that may also not have been of local provenance. We have a a so-called “hybrid swarm”, showing the characteristic “hybrid vigour” of such situations.
Question remain: what to do about this? Should the whole population be removed, including seedlings that will continue to emerge after these plants are killed? Should only plants threatening the rare plant community be removed? Should the plants that are clearly hybrids be removed and plants showing characteristics of the “true” species be kept? Should the plants be left to continue to thrive, creating a novel ecosystem that may be better suited to a changing environment, given its hybrid vigour and the thought that it may also provide habitat for fauna? If the decision is made to take some of the control steps above, are the significant resources even available to undertake the task?
Continued below....
Close inspection of the grevilleas here revealed resemblances of some of them to commonly planted garden species, including the Rosemary Grevillea (G. rosmarinifolia) and Woolly Grevillea (G. lanigera). We questioned too, whether the original plantings of G. juniperina, which by the way has natural populations in the ACT, including upriver from this site, were indeed here of the local provenance plants. Margaret pointed out that this widespread species has, according to PlantNet, no fewer than nine subspecies. The species has long been in the nursery trade, and those original plantings here at the Murrumbidgee may very easily have been sourced from nursery plants from anywhere within the species’ range.
Here then, we have a typical situation where a new population has emerged, with genes infused from nearby garden plantings of clearly non-locally indigenous species, and into plants that may also not have been of local provenance. We have a a so-called “hybrid swarm”, showing the characteristic “hybrid vigour” of such situations.
Question remain: what to do about this? Should the whole population be removed, including seedlings that will continue to emerge after these plants are killed? Should only plants threatening the rare plant community be removed? Should the plants that are clearly hybrids be removed and plants showing characteristics of the “true” species be kept? Should the plants be left to continue to thrive, creating a novel ecosystem that may be better suited to a changing environment, given its hybrid vigour and the thought that it may also provide habitat for fauna? If the decision is made to take some of the control steps above, are the significant resources even available to undertake the task?
Continued below....
michaelb
wrote:
22 Aug 2018
Continued from above (Rainer Rehwinkel on FaceBook)....
Since first appearing on Facebook, this post has generated a vigorous discussion, ranging between the extremes: 1. Remove all non-locally sourced plants; 2. Remove only the plants that are threatening the rare grassland community; and, several points lying somewhere in the middle, including, 3. Remove all plants that are clearly hybrids, but keep extensive areas of non-hybrid plants to continue to provide nectar resources for honeyeaters, because the site is in an important migration route for honeyeaters.
No doubt the debate will continue, because this issue is not confined to this site; it is also found in various permutations elsewhere. For example, I have previously FB-posted about non-local and hybrid swarming wattles at another site down-river!
The following concluding remarks were written a week after the above notes, in response to much debate on FB, and on Canberra NatureMap. It is still not clear what is to be done with these grevilleas. As one ACT Government staff member argues, the grevilleas appear to be an important nectar resource, however the issue is that the population at Pine Island is most probably now much larger than the original local population of G. juniperina is likely to have been. Furthermore, the plants here are pretty much all along a continuum of hybridisation, from almost pure G. juniperina, to plants all-but-indistinguishable from G. rosmarinifolia. In addition, there are genes from G. lanigera, there, and as the ACT staffer mentions, also from G. “Canberra Gem”, which is itself a hybrid of juniperina and rosmarinifolia. This will have implications for their progeny should they recruit here.
Continued below....
Since first appearing on Facebook, this post has generated a vigorous discussion, ranging between the extremes: 1. Remove all non-locally sourced plants; 2. Remove only the plants that are threatening the rare grassland community; and, several points lying somewhere in the middle, including, 3. Remove all plants that are clearly hybrids, but keep extensive areas of non-hybrid plants to continue to provide nectar resources for honeyeaters, because the site is in an important migration route for honeyeaters.
No doubt the debate will continue, because this issue is not confined to this site; it is also found in various permutations elsewhere. For example, I have previously FB-posted about non-local and hybrid swarming wattles at another site down-river!
The following concluding remarks were written a week after the above notes, in response to much debate on FB, and on Canberra NatureMap. It is still not clear what is to be done with these grevilleas. As one ACT Government staff member argues, the grevilleas appear to be an important nectar resource, however the issue is that the population at Pine Island is most probably now much larger than the original local population of G. juniperina is likely to have been. Furthermore, the plants here are pretty much all along a continuum of hybridisation, from almost pure G. juniperina, to plants all-but-indistinguishable from G. rosmarinifolia. In addition, there are genes from G. lanigera, there, and as the ACT staffer mentions, also from G. “Canberra Gem”, which is itself a hybrid of juniperina and rosmarinifolia. This will have implications for their progeny should they recruit here.
Continued below....
michaelb
wrote:
19 Sep 2018
Continued from above (Rainer Rehwinkel on FaceBook)....
So what we have is the classic hybrid swarm, showing the classic hybrid vigour, and it is most likely this that is causing the population explosion and the resulting invasion into the native systems here, at least one of which is a Critically Endangered Ecological Community (CEEC), the Natural Temperate Grassland of the South Eastern Highlands (NTG SEH, see the link, below).
The added boon for local populations of honeyeaters and other small passerines that may be using this site need to be carefully weighed up with the likely dis-benefits, especially the risk of the spread of genes from the hybrid swarm into more intact populations of both G. juniperina and G. lanigera, as I understand it, both upstream and downstream from this site. Respected Canberra naturalist, Ian Fraser, in his comment to the original FB post, was unequivocal: to paraphrase him, no argument, get rid of them all!
Possibly the most important lesson here, is, that when undertaking plantings in or near bush settings, extreme care must be taken in sourcing plants, and choosing the planting densities and the planting locations.
Rainer Rehwinkel, 19 August, 2018.
To see the photos from the site, and the interesting comments generated by the original post, see my FB page.
So what we have is the classic hybrid swarm, showing the classic hybrid vigour, and it is most likely this that is causing the population explosion and the resulting invasion into the native systems here, at least one of which is a Critically Endangered Ecological Community (CEEC), the Natural Temperate Grassland of the South Eastern Highlands (NTG SEH, see the link, below).
The added boon for local populations of honeyeaters and other small passerines that may be using this site need to be carefully weighed up with the likely dis-benefits, especially the risk of the spread of genes from the hybrid swarm into more intact populations of both G. juniperina and G. lanigera, as I understand it, both upstream and downstream from this site. Respected Canberra naturalist, Ian Fraser, in his comment to the original FB post, was unequivocal: to paraphrase him, no argument, get rid of them all!
Possibly the most important lesson here, is, that when undertaking plantings in or near bush settings, extreme care must be taken in sourcing plants, and choosing the planting densities and the planting locations.
Rainer Rehwinkel, 19 August, 2018.
To see the photos from the site, and the interesting comments generated by the original post, see my FB page.
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Nearby sightings
Location information
- Coordinates 149.071843-35.437783
- Altitude 557.7m
- Maps Pine Island to Point Hut
- Places Bonython, ACT
Sighting information
- 1,001 - 10,000 Abundance
- 17 Jul 2018 06:45 PM Recorded on
- michaelb Recorded by
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Collections
michaelb's Flagged sightings
Additional information
- 1 metre to 5 metres Plant height
Species information
- Grevillea juniperina Scientific name
- Grevillea Common name
- Not Sensitive
- Local native
- Non-Invasive
- Up to 801.09m Recorded at altitude
- Machine learning
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In flower
- External link More information
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- Overall Fit for scientific/research use
- Images or audio
- More than one media file
- Confirmed by an expert moderator
- Nearby sighting(s) of same species
- GPS evidence of location
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