Climate Matching Map
| Attachment | Size |
|---|---|
| ClimateMatch_CA_Senecio_angustifolius.pdf (1.09 MB) | 1.09 MB |
1. Question 1
Yes
1
High
The species is now well established at widely scattered locations in the North San Diego area (USMC Camp Pendleton) and at 1-3 locations in Orange County. (Calflora & CCH2)
The species has established in agricultural rooibos tea (Aspalathus linearis) plantations in South Africa slightly North and West of its native range. Although possibly only an agricultural weed here, I am including these South African occurrences as "where it is not native". (Senecio angustifolius as the major source . . .)
iNaturalist shows no occurrences outside of South Africa, other than those in California. (iNaturalist)
Outside of its native range in South Africa, there dubious records from Mexico, Germany, Spain and Taiwan, which are all considered to be in error and are ignored in this assessment. For a discussion of these, please see the "Notes" at the end of this assessment
Other than California and in tea plantations outside its native South African range (and unlikely in Mexico, Germany, Spain or Taiwan), I could find no other documentation of the species naturalizing.
The species is referenced as a common "weed" in tea plantations adjacent to but outside its native South African range. (Senecio a. - rooibos tea)
The species has established in agricultural rooibos tea (Aspalathus linearis) plantations in South Africa slightly North and West of its native range. Although possibly only an agricultural weed here, I am including these South African occurrences as "where it is not native". (Senecio angustifolius as the major source . . .)
iNaturalist shows no occurrences outside of South Africa, other than those in California. (iNaturalist)
Outside of its native range in South Africa, there dubious records from Mexico, Germany, Spain and Taiwan, which are all considered to be in error and are ignored in this assessment. For a discussion of these, please see the "Notes" at the end of this assessment
Other than California and in tea plantations outside its native South African range (and unlikely in Mexico, Germany, Spain or Taiwan), I could find no other documentation of the species naturalizing.
The species is referenced as a common "weed" in tea plantations adjacent to but outside its native South African range. (Senecio a. - rooibos tea)
“GBIF Backbone Taxonomy. Checklist Dataset Https: Doi.org 10.15468 39omei Accessed via GBIF.Org on 09-2022”. 2022. https://www.gbif.org/species/8043963.
Calflora,. 2022. “Observation Search - Senecio Angustifolius”. https://www.calflora.org/entry/observ.html$\#$srch=t\&taxon=Senecio+angustifolius\&cols=b\&inma=t\&y=36.7126\&x=-119.6126\&z=6\&cch=t\&inat=r.
Raza-Zarate, Ramon. (2019) 2019. “Laurel Regeneration in the Presence of Disturbance Events: A Case Study”. Forest Science 2019.
Van Wyk, B.E., M.A. Stander, and H.S. Long. 2017. “Senecio Angustifolius As the Major Source of Pyrrolizidine Alkaloid Contamination of Rooibos Tea (Aspalathus Linearis)”. South African Journal of Botany 110: 124-31. doi:10.1016/j.sajb.2017.01.013.
2022. “INaturalist Observations: Senecio Angustifolius”. https://www.inaturalist.org/observations?place_id=any\&taxon_id=594182.
“SEINet Portal Network Collections Search Results Accessed 9-2022”. 2022. https://swbiodiversity.org/seinet/collections/listtabledisplay.php?collector=Tlapa+Almonte\&sortfield1=o.sciname\&sortfield2=\&sortorder=\&page=3.
“CCH2 Portal Collections Results for Senecio Angustifolia Accessed 9-2022”. 2022. https://www.cch2.org/portal/collections/listtabledisplay.php.
2. Question 2
Yes
2
High
The species is now well established at widely scattered locations in the North San Diego area (USMC Camp Pendleton) and at 1-3 locations in Orange County. (Calflora, CCH2, and Simpson, et al)
Outside of its native range in South Africa, occurrences on GBIF from Mexico, Germany, Spain and Taiwan are all likely in error and omitted. See the "Notes" section for further discussion.
The species has established in agricultural tea plantations in South Africa slightly North and West of its native range. Although possibly only an agricultural weed here, I am including these South African occurrences as "naturalized in a similar climate". (Senecio a. - rooibos tea)
iNaturalist shows no occurrences outside of South Africa, other than those in California. (iNaturalist)
Other than California and in tea plantations outside its native South African range, I could find no documentation of the species naturalizing. However, the species is referenced as a common "weed" in tea plantations outside but adjacent to its native South African range.
A Climate Match SHOULD include plants that have naturalized, even in a horticultural or agricultural environment (although not necessarily invasive). Because of it being naturalized outside of its native range in South Africa, this question must be answered as a "YES".
Outside of its native range in South Africa, occurrences on GBIF from Mexico, Germany, Spain and Taiwan are all likely in error and omitted. See the "Notes" section for further discussion.
The species has established in agricultural tea plantations in South Africa slightly North and West of its native range. Although possibly only an agricultural weed here, I am including these South African occurrences as "naturalized in a similar climate". (Senecio a. - rooibos tea)
iNaturalist shows no occurrences outside of South Africa, other than those in California. (iNaturalist)
Other than California and in tea plantations outside its native South African range, I could find no documentation of the species naturalizing. However, the species is referenced as a common "weed" in tea plantations outside but adjacent to its native South African range.
A Climate Match SHOULD include plants that have naturalized, even in a horticultural or agricultural environment (although not necessarily invasive). Because of it being naturalized outside of its native range in South Africa, this question must be answered as a "YES".
Calflora,. 2022. “Observation Search - Senecio Angustifolius”. https://www.calflora.org/entry/observ.html$\#$srch=t\&taxon=Senecio+angustifolius\&cols=b\&inma=t\&y=36.7126\&x=-119.6126\&z=6\&cch=t\&inat=r.
Van Wyk, B.E., M.A. Stander, and H.S. Long. 2017. “Senecio Angustifolius As the Major Source of Pyrrolizidine Alkaloid Contamination of Rooibos Tea (Aspalathus Linearis)”. South African Journal of Botany 110: 124-31. doi:10.1016/j.sajb.2017.01.013.
“GBIF Backbone Taxonomy. Checklist Dataset Https: Doi.org 10.15468 39omei Accessed via GBIF.Org on 09-2022”. 2022. https://www.gbif.org/species/8043963.
2022. “INaturalist Observations: Senecio Angustifolius”. https://www.inaturalist.org/observations?place_id=any\&taxon_id=594182.
“CCH2 Portal Collections Results for Senecio Angustifolia Accessed 9-2022”. 2022. https://www.cch2.org/portal/collections/listtabledisplay.php.
Simpson, Michael S., and Ron Vanderhoff. (2023) 2022. “Taxonomic Identity of a Recently Naturalized Senecio Species in California”. Madrono. https://doi.org/10.3120/0024-9637-69.3.286.
3. Question 3
No
0
Medium
The species is now well established at widely scattered locations in the North San Diego area at USMC Camp Pendleton, and at 1-3 locations in Orange County. (Calflora & CCH2) At USMC Camp Pendleton it is rather well established. Brief conversations with Jon Rebman, San Diego Natural History Museum (J. Rebman, pers. comm.) and one of the Pendleton staff biologists who is working on the management. There is certainly concern on their part, but there is no public documentation as yet. There are now at least nine populations (each separated by at least 2 km) and it has spread over several kilometers and through at least four different watersheds.
It has certainly naturalized there and it's footprint is expanding. However, it's environmental impacts at USMC Pendleton are not yet likely understood or quantified since it has only been on the site for perhaps little over a decade.
The species has established in agricultural tea plantations in South Africa slightly North and West of its native range. Although possibly only an agricultural weed here, I am including these South African occurrences as "being invasive". (Senecio a. - rooibos tea)
Outside of its native range in South Africa, occurrences on GBIF from Mexico, Germany, Spain and Taiwan are all likely in error and omitted. See the "Notes" section for further discussion. (GBIF) (Forest Science) (SEINet)
iNaturalist shows no occurrences outside of South Africa, other than those in California. (iNaturalist)
Other than California and in tea plantations outside its native South African range (and likely misidentifications in Mexico), I could find no documentation of the species naturalizing. However, the species is referenced as a common "weed" in tea plantations adjacent to its native South African range.
In summary, "Invasiveness", as defined by PRE, is not thoroughly established here, at least not yet. Based on the PRE definition of "invasive", this question must be answered as a "NO".
It has certainly naturalized there and it's footprint is expanding. However, it's environmental impacts at USMC Pendleton are not yet likely understood or quantified since it has only been on the site for perhaps little over a decade.
The species has established in agricultural tea plantations in South Africa slightly North and West of its native range. Although possibly only an agricultural weed here, I am including these South African occurrences as "being invasive". (Senecio a. - rooibos tea)
Outside of its native range in South Africa, occurrences on GBIF from Mexico, Germany, Spain and Taiwan are all likely in error and omitted. See the "Notes" section for further discussion. (GBIF) (Forest Science) (SEINet)
iNaturalist shows no occurrences outside of South Africa, other than those in California. (iNaturalist)
Other than California and in tea plantations outside its native South African range (and likely misidentifications in Mexico), I could find no documentation of the species naturalizing. However, the species is referenced as a common "weed" in tea plantations adjacent to its native South African range.
In summary, "Invasiveness", as defined by PRE, is not thoroughly established here, at least not yet. Based on the PRE definition of "invasive", this question must be answered as a "NO".
Razo-Zárate, Ramón, Laura Berenice Retama-Cázares, Rodrigo Rodríguez-Laguna, Abraham Palacios-Romero, Joel Meza-Rangel, Juan Capulín-Grande, Pablo Irving Fragoso-López, and Hermann Jesús Cortés-Blobaum. 2019. “Laurel (Litsea Glaucescens Kunth) Regeneration in the Presence of Disturbance Events: A Case Study”. Forest Science 65: 688\textendash692. doi:10.1093/forsci/fxz032.
Calflora,. 2022. “Observation Search - Senecio Angustifolius”. https://www.calflora.org/entry/observ.html$\#$srch=t\&taxon=Senecio+angustifolius\&cols=b\&inma=t\&y=36.7126\&x=-119.6126\&z=6\&cch=t\&inat=r.
“SEINet Portal Network Collections Search Results Accessed 9-2022”. 2022. https://swbiodiversity.org/seinet/collections/listtabledisplay.php?collector=Tlapa+Almonte\&sortfield1=o.sciname\&sortfield2=\&sortorder=\&page=3.
Van Wyk, B.E., M.A. Stander, and H.S. Long. 2017. “Senecio Angustifolius As the Major Source of Pyrrolizidine Alkaloid Contamination of Rooibos Tea (Aspalathus Linearis)”. South African Journal of Botany 110: 124-31. doi:10.1016/j.sajb.2017.01.013.
“GBIF Backbone Taxonomy. Checklist Dataset Https: Doi.org 10.15468 39omei Accessed via GBIF.Org on 09-2022”. 2022. https://www.gbif.org/species/8043963.
2022. “INaturalist Observations: Senecio Angustifolius”. https://www.inaturalist.org/observations?place_id=any\&taxon_id=594182.
“CCH2 Portal Collections Results for Senecio Angustifolia Accessed 9-2022”. 2022. https://www.cch2.org/portal/collections/listtabledisplay.php.
4. Question 4
No
0
Medium
The species is now well established at widely scattered locations in the North San Diego area (USMC Camp Pendleton) and at 1-3 locations in Orange County. (Calflora and CCH2)
The species has established in agricultural tea plantations in South Africa slightly North and West of its native range, but within a California climate match. Although possibly only an agricultural weed here, these occurrences are interesting but "invasiveness" is not necessarily certain. This is an agricultural weed in an irrigated environment. The plants ability to move outside of this environment is not established. I am not including these South African occurrences as "being invasive . . . in a similar climate". (Senecio a. - rooibos tea)
Occurrences in Mexico, Germany, Spain and Taiwan are all considered erroneous (see Notes for further discussion). (GBIF)
iNaturalist shows no occurrences outside of South Africa, other than those in California. (iNaturalist)
In summary, "Invasiveness", as defined by PRE, is not thoroughly established here, at least not yet. Secondly, a Climate Match should probably NOT include plants in a horticultural or agricultural environment. In irrigated agricultural situations, we should be pretty strict with the climate match. Based on the definition of invasive and discounting agricultural weed occurrences, this question must be answered as a "NO".
The species has established in agricultural tea plantations in South Africa slightly North and West of its native range, but within a California climate match. Although possibly only an agricultural weed here, these occurrences are interesting but "invasiveness" is not necessarily certain. This is an agricultural weed in an irrigated environment. The plants ability to move outside of this environment is not established. I am not including these South African occurrences as "being invasive . . . in a similar climate". (Senecio a. - rooibos tea)
Occurrences in Mexico, Germany, Spain and Taiwan are all considered erroneous (see Notes for further discussion). (GBIF)
iNaturalist shows no occurrences outside of South Africa, other than those in California. (iNaturalist)
In summary, "Invasiveness", as defined by PRE, is not thoroughly established here, at least not yet. Secondly, a Climate Match should probably NOT include plants in a horticultural or agricultural environment. In irrigated agricultural situations, we should be pretty strict with the climate match. Based on the definition of invasive and discounting agricultural weed occurrences, this question must be answered as a "NO".
Calflora,. 2022. “Observation Search - Senecio Angustifolius”. https://www.calflora.org/entry/observ.html$\#$srch=t\&taxon=Senecio+angustifolius\&cols=b\&inma=t\&y=36.7126\&x=-119.6126\&z=6\&cch=t\&inat=r.
“SEINet Portal Network Collections Search Results Accessed 9-2022”. 2022. https://swbiodiversity.org/seinet/collections/listtabledisplay.php?collector=Tlapa+Almonte\&sortfield1=o.sciname\&sortfield2=\&sortorder=\&page=3.
Van Wyk, B.E., M.A. Stander, and H.S. Long. 2017. “Senecio Angustifolius As the Major Source of Pyrrolizidine Alkaloid Contamination of Rooibos Tea (Aspalathus Linearis)”. South African Journal of Botany 110: 124-31. doi:10.1016/j.sajb.2017.01.013.
“GBIF Backbone Taxonomy. Checklist Dataset Https: Doi.org 10.15468 39omei Accessed via GBIF.Org on 09-2022”. 2022. https://www.gbif.org/species/8043963.
2022. “INaturalist Observations: Senecio Angustifolius”. https://www.inaturalist.org/observations?place_id=any\&taxon_id=594182.
“CCH2 Portal Collections Results for Senecio Angustifolia Accessed 9-2022”. 2022. https://www.cch2.org/portal/collections/listtabledisplay.php.
5. Question 5
Yes
1
Very High
Several other species in the genus Senecio are invasive. In California, the Jepson eflora lists 8 Senecio as naturalized. The Cal-IPC inventory lists four species. (Cal-IPC) GISD lists seven species as invasive and CABI lists several species as invasive. (GISD)
“The Cal-IPC Inventory Access 9-2022”. 2022. https://www.cal-ipc.org/plants/inventory/.
“Global Invasive Species Database: Senecio Species, Accessed 09-22”. 2022.
“Jepson EFlora, Https: Ucjeps.berkeley.edu Eflora [accessed Sept, 2022]”. 2022. https://ucjeps.berkeley.edu/eflora/search_eflora.php?name=.
6. Question 6
Yes
2
Very High
The large majority of world occurrences are INSIDE a California climate match, as shown in the climate matching map and compared with valid GBIF and iNaturalist occurrences. Approximately 80% match to California. Ignoring invalid points in Mexico, Europe, Asia as discussed in prior questions. (GBIF & iNaturalist)
I am also including occurrences where it is documented as a weed in agricultural tea plantations in South Africa slightly North and West of its native range. Although possibly only an agricultural weed here, these occurrences are included. (Senecio a. - rooibos tea)
I am also including occurrences where it is documented as a weed in agricultural tea plantations in South Africa slightly North and West of its native range. Although possibly only an agricultural weed here, these occurrences are included. (Senecio a. - rooibos tea)
Van Wyk, B.E., M.A. Stander, and H.S. Long. 2017. “Senecio Angustifolius As the Major Source of Pyrrolizidine Alkaloid Contamination of Rooibos Tea (Aspalathus Linearis)”. South African Journal of Botany 110: 124-31. doi:10.1016/j.sajb.2017.01.013.
“GBIF Backbone Taxonomy. Checklist Dataset Https: Doi.org 10.15468 39omei Accessed via GBIF.Org on 09-2022”. 2022. https://www.gbif.org/species/8043963.
2022. “INaturalist Observations: Senecio Angustifolius”. https://www.inaturalist.org/observations?place_id=any\&taxon_id=594182.
7. Question 7
No
0
Low
I can find no published evidence of this species overtopping or smothering other vegetation. Collection details from CA (CCH2) do not mention this. But its mere presence does imply at least some displacement of native biomass.
The plant is variably described as:
"Erect or straggling, slender-stemmed shrublet, up to 500 mm tall". (Senecio angustifolius Thunb. in ref.)
"Twiggy, glabrous shrublet to 60 cm." (Senecio angustifolius Thunb. in ref.)
"Perennial herb to shrub, up to 1 m tall, 2 m wide, at maturity woody at base" (Simpson, M.S.)
Given the size and habit of the plant it would be reasonably significant in mass when compared to other species within its chosen plant community, thus displacing, shading and interrupting an equivalent amount of native vegetation. However, without more published evidence I am remaining conservative and assigning a No answer.
The plant is variably described as:
"Erect or straggling, slender-stemmed shrublet, up to 500 mm tall". (Senecio angustifolius Thunb. in ref.)
"Twiggy, glabrous shrublet to 60 cm." (Senecio angustifolius Thunb. in ref.)
"Perennial herb to shrub, up to 1 m tall, 2 m wide, at maturity woody at base" (Simpson, M.S.)
Given the size and habit of the plant it would be reasonably significant in mass when compared to other species within its chosen plant community, thus displacing, shading and interrupting an equivalent amount of native vegetation. However, without more published evidence I am remaining conservative and assigning a No answer.
“CCH2 Portal Collections Results for Senecio Angustifolia Accessed 9-2022”. 2022. https://www.cch2.org/portal/collections/listtabledisplay.php.
Simpson, Michael S., and Ron Vanderhoff. (2023) 2022. “Taxonomic Identity of a Recently Naturalized Senecio Species in California”. Madrono. https://doi.org/10.3120/0024-9637-69.3.286.
Online, World Flora. 2022. “Senecio Angustifolius (Thunb.) Willd”. http://worldfloraonline.org/taxon/wfo-0000004601.
8. Question 8
No
0
Medium
No evidence anywhere in the literature of impacts to fire regimes. Leaving unanswered.
The stature of this plant is described as up to 1 m high and 1-2 m wide at maturity and as an "Erect or straggling, slender-stemmed shrublet" (Senecio angustifolius Thunb. in ref.), "Twiggy, glabrous shrublet" (Senecio angustifolius Thunb. in ref.), or
"Perennial herb to shrub . . . at maturity woody at base" (Simpson, M.).
Images on Calflora (Calflora 2022) indicate that although the leaves of the shrub are small to very small, the accumulated dead branches could create some fuels. Since this plant is currently growing in areas with ample fuels, it does not change the fire regime.
The stature of this plant is described as up to 1 m high and 1-2 m wide at maturity and as an "Erect or straggling, slender-stemmed shrublet" (Senecio angustifolius Thunb. in ref.), "Twiggy, glabrous shrublet" (Senecio angustifolius Thunb. in ref.), or
"Perennial herb to shrub . . . at maturity woody at base" (Simpson, M.).
Images on Calflora (Calflora 2022) indicate that although the leaves of the shrub are small to very small, the accumulated dead branches could create some fuels. Since this plant is currently growing in areas with ample fuels, it does not change the fire regime.
Simpson, Michael, and Ron Vanderhoff. (2023) 2022. “Taxonomic Identity of a Recently Naturalized Senecio Species in California”. Madrono. https://doi.org/10.3120/0024-9637-69.3.286.
Online, World Flora. 2022. “Senecio Angustifolius (Thunb.) Willd”. http://worldfloraonline.org/taxon/wfo-0000004601.
Calflora,. 2022. “Observation Search - Senecio Angustifolius”. https://www.calflora.org/entry/observ.html$\#$srch=t\&taxon=Senecio+angustifolius\&cols=b\&inma=t\&y=36.7126\&x=-119.6126\&z=6\&cch=t\&inat=r.
9. Question 9
Yes
1
High
A strong reference to the plant in a paper documenting its occurrence in rooibos tea production agricultural fields in South Africa states:
"Further investigation revealed an explanation for the presence of PAs (pyrrolizidine alkaloids) in rooibos plants, namely that it can be absorbed from the soil where rooibos plants co-occur with Senecio plants. Soil collected at the roots of Senecio species contained relatively high levels of senecionine and senecionine N-oxide. This preliminary study of carefully collected soil samples showed that soil can be contaminated with PAs and that this offers the only plausible explanation for the presence of PAs in rooibos tea plants."
The same South African paper states the following about toxins found in this species:
"Pyrrolizidine alkaloids (PAs) and their N-oxides (PANOs) are amongst the most widely distributed natural toxins produced by plants and are known to be hepatotoxic to humans and animals (Bull et al., 1968, Mattocks, 1986)." The striking part of that paper was the german BfR, similar to our FDA or EPA, found these toxic alkaloids in rooibos tea products across the nation, and the paper's authors tracked down the source, which is this weed.
Lastly, the same paper later offers this about livestock:
". . . the plant causes chronic PA (pyrrolizidine alkaloid) poisoning in livestock . . .". (Senecio a. - rooibos tea)
However, the tea contamination may be site specific and species specific and does not necessarily confirm this would occur with other plant species or in natural areas. Nonetheless, the commente re livestock poisoning is with merit. Based on the livestock poisoning reference and the pyrrolizidine alkaloid documentation I am answering YES, with a HIGH confidence.
"Further investigation revealed an explanation for the presence of PAs (pyrrolizidine alkaloids) in rooibos plants, namely that it can be absorbed from the soil where rooibos plants co-occur with Senecio plants. Soil collected at the roots of Senecio species contained relatively high levels of senecionine and senecionine N-oxide. This preliminary study of carefully collected soil samples showed that soil can be contaminated with PAs and that this offers the only plausible explanation for the presence of PAs in rooibos tea plants."
The same South African paper states the following about toxins found in this species:
"Pyrrolizidine alkaloids (PAs) and their N-oxides (PANOs) are amongst the most widely distributed natural toxins produced by plants and are known to be hepatotoxic to humans and animals (Bull et al., 1968, Mattocks, 1986)." The striking part of that paper was the german BfR, similar to our FDA or EPA, found these toxic alkaloids in rooibos tea products across the nation, and the paper's authors tracked down the source, which is this weed.
Lastly, the same paper later offers this about livestock:
". . . the plant causes chronic PA (pyrrolizidine alkaloid) poisoning in livestock . . .". (Senecio a. - rooibos tea)
However, the tea contamination may be site specific and species specific and does not necessarily confirm this would occur with other plant species or in natural areas. Nonetheless, the commente re livestock poisoning is with merit. Based on the livestock poisoning reference and the pyrrolizidine alkaloid documentation I am answering YES, with a HIGH confidence.
Van Wyk, B.E., M.A. Stander, and H.S. Long. 2017. “Senecio Angustifolius As the Major Source of Pyrrolizidine Alkaloid Contamination of Rooibos Tea (Aspalathus Linearis)”. South African Journal of Botany 110: 124-31. doi:10.1016/j.sajb.2017.01.013.
10. Question 10
No
0
Low
This plant is variably described as:
"Erect or straggling, slender-stemmed shrublet, up to 500 mm tall". (Senecio angustifolius Thunb. in ref.)
"Twiggy, glabrous shrublet to 60 cm." (Senecio angustifolius Thunb. in ref.)
"Erect or straggling, slender-stemmed shrublet, up to 500 mm tall." (Plants of the Greater Cape)
"Perennial herb to shrub, up to 1 m tall, 2 m wide, at maturity woody at base" (Simpson, M.S.)
These characters are inconclusive re its fire ecology. In observation and from limited comments in California collections it appears to become a naturalized component of the pre-existing plant community. None of the Calflora or CCH records indicate dense, thick or impenetrable stands (Calflora & CCH2). The comments that are included state "uncommon" and "rare", which would not imply thickets. Without more references, I am giving a "No" and a low confidence score.
In the rooibos tea paper (Senecio angustifolius Thunb.) some of the farms are described as "heavily infested." While this may be because of soil disturbance at the tea farms, it is possible we could see this type of dense infestations in California.
"Erect or straggling, slender-stemmed shrublet, up to 500 mm tall". (Senecio angustifolius Thunb. in ref.)
"Twiggy, glabrous shrublet to 60 cm." (Senecio angustifolius Thunb. in ref.)
"Erect or straggling, slender-stemmed shrublet, up to 500 mm tall." (Plants of the Greater Cape)
"Perennial herb to shrub, up to 1 m tall, 2 m wide, at maturity woody at base" (Simpson, M.S.)
These characters are inconclusive re its fire ecology. In observation and from limited comments in California collections it appears to become a naturalized component of the pre-existing plant community. None of the Calflora or CCH records indicate dense, thick or impenetrable stands (Calflora & CCH2). The comments that are included state "uncommon" and "rare", which would not imply thickets. Without more references, I am giving a "No" and a low confidence score.
In the rooibos tea paper (Senecio angustifolius Thunb.) some of the farms are described as "heavily infested." While this may be because of soil disturbance at the tea farms, it is possible we could see this type of dense infestations in California.
Simpson, Michael S., and Ron Vanderhoff. (2023) 2022. “Taxonomic Identity of a Recently Naturalized Senecio Species in California”. Madrono. https://doi.org/10.3120/0024-9637-69.3.286.
“African Plant Database - Jacobeaea Angustifolia Thunb. Accessed 9-2022”. 2022. https://africanplantdatabase.ch/en/nomen/97996.
Snijman, D.A. 2013. Plants of the Greater Cape Floristic Region: 2. The Extra Cape Flora. Vol. 30. South African National Biodiversity Institute (SANBI Publishing). https://www.sanbi.org/documents/plants-of-the-greater-cape-floristic-region-the-extra-cape-flora-strelitzia-30/.
“CCH2 Portal Collections Results for Senecio Angustifolia Accessed 9-2022”. 2022. https://www.cch2.org/portal/collections/listtabledisplay.php.
Calflora,. 2022. “Observation Search - Senecio Angustifolius”. https://www.calflora.org/entry/observ.html$\#$srch=t\&taxon=Senecio+angustifolius\&cols=b\&inma=t\&y=36.7126\&x=-119.6126\&z=6\&cch=t\&inat=r.
“GBIF Backbone Taxonomy. Checklist Dataset Https: Doi.org 10.15468 39omei Accessed via GBIF.Org on 09-2022”. 2022. https://www.gbif.org/species/8043963.
Online, World Flora. 2022. “Senecio Angustifolius (Thunb.) Willd”. http://worldfloraonline.org/taxon/wfo-0000004601.
11. Question 11
No
0
High
No evidence or literature to support this. Basal branching, non succulence, lack of geophytic organs, all lead to no top vegetative reproduction. Additionally, other non succulent members of the Senecio genus are almost always obligate seeders and do not naturally reproduce vegetatively. (Anonymous - CABI) (Walter et al)
“CABI Search Results for Senecio, Accessed 9-2022”. 2022. https://www.cabidigitallibrary.org/action/doSearch?AllField=Senecio.
Walter, Greg M., Richard J. Abbott, Adrian C. Brennan, Jon R. Bridle, Mark Chapman, James Clark, Dmitry Filatov, Bruno Nevado, Daniel Ortiz-Barrientos, and Simon J. Hiscock. 2020. “Senecio As a Model System for Integrating Studies of Genotype, Phenotype and Fitness”. New Phytologist 226: 326-44. doi:10.1111/nph.16434.
12. Question 12
No
0
High
Almost certainly an obligate seeder, as with almost all non succulent Senecio. No evidence of any other form of reproduction in the literature. (Anonymous - CABI) (Walter)
“CABI Search Results for Senecio, Accessed 9-2022”. 2022. https://www.cabidigitallibrary.org/action/doSearch?AllField=Senecio.
Walter, Greg M., Richard J. Abbott, Adrian C. Brennan, Jon R. Bridle, Mark Chapman, James Clark, Dmitry Filatov, Bruno Nevado, Daniel Ortiz-Barrientos, and Simon J. Hiscock. 2020. “Senecio As a Model System for Integrating Studies of Genotype, Phenotype and Fitness”. New Phytologist 226: 326-44. doi:10.1111/nph.16434.
13. Question 13
Yes
1
High
Yes, the species is almost certainly an obligate seeder. (Senecio a. - anonymous), (Strelitzia) (Simpson) (Walter)
Seeds were abundant on a plant examined in Orange County (8,200 potential seeds). It would be assumed that with such high seed production that a good number would be viable. (Observation of Senecio angustifolius – Calflora)
Seeds were abundant on a plant examined in Orange County (8,200 potential seeds). It would be assumed that with such high seed production that a good number would be viable. (Observation of Senecio angustifolius – Calflora)
Simpson, Michael S., and Ron Vanderhoff. (2023) 2022. “Taxonomic Identity of a Recently Naturalized Senecio Species in California”. Madrono. https://doi.org/10.3120/0024-9637-69.3.286.
Snijman, D.A. 2013. Plants of the Greater Cape Floristic Region: 2. The Extra Cape Flora. Vol. 30. South African National Biodiversity Institute (SANBI Publishing). https://www.sanbi.org/documents/plants-of-the-greater-cape-floristic-region-the-extra-cape-flora-strelitzia-30/.
Online, World Flora. 2022. “Senecio Angustifolius (Thunb.) Willd”. http://worldfloraonline.org/taxon/wfo-0000004601.
Walter, Greg M., Richard J. Abbott, Adrian C. Brennan, Jon R. Bridle, Mark Chapman, James Clark, Dmitry Filatov, Bruno Nevado, Daniel Ortiz-Barrientos, and Simon J. Hiscock. 2020. “Senecio As a Model System for Integrating Studies of Genotype, Phenotype and Fitness”. New Phytologist 226: 326-44. doi:10.1111/nph.16434.
“Observation of Senecio Angustifolius \textendash Calflora”. n.d. https://www.calflora.org/entry/occdetail.html?seq_num=po145181.
14. Question 14
Yes
1
Very High
A single semi-mature plant was counted for seeds in Orange County. +-50-60 seeds were counted per head. Counted +-150 heads on the semi-mature plant. That is a total of approximately 8,250 potential seeds on this plant at that moment. Considering that this species flowers and seeds almost continually throughout the year, the total seed production is well over 1,000/year. (Observation of Senecio angustifolius – Calflora)
Limited other documentation about seed production. However, the very long flowering and seeding period, being year-round or nearly so (CCH2 and Calflora), abundance of flower heads (Simpson et al and Observation of Senecio angustifolius – Calflora.) would indicate well over >1,000 achenes per year per plant.
Other shrubby Senecio species (S. jacobaea) have high seed viability rates, and its likely this species also has similar high viability rates, producing over 1,000 viable seeds per year. Viability in a study of shrubby Senecio jacobaea was typically from 20-70%. Seed viability was fairly long, at 6 years viability was still >5% in many soil samples. The time for seed viability to decline to 1% was estimated to be at least 4-5 years in the 0-2 cm surface layer and 10-16 years below 4 cm soil depth. (Thompson, A)
Limited other documentation about seed production. However, the very long flowering and seeding period, being year-round or nearly so (CCH2 and Calflora), abundance of flower heads (Simpson et al and Observation of Senecio angustifolius – Calflora.) would indicate well over >1,000 achenes per year per plant.
Other shrubby Senecio species (S. jacobaea) have high seed viability rates, and its likely this species also has similar high viability rates, producing over 1,000 viable seeds per year. Viability in a study of shrubby Senecio jacobaea was typically from 20-70%. Seed viability was fairly long, at 6 years viability was still >5% in many soil samples. The time for seed viability to decline to 1% was estimated to be at least 4-5 years in the 0-2 cm surface layer and 10-16 years below 4 cm soil depth. (Thompson, A)
“CCH2 Portal Collections Results for Senecio Angustifolia Accessed 9-2022”. 2022. https://www.cch2.org/portal/collections/listtabledisplay.php.
Calflora,. 2022. “Observation Search - Senecio Angustifolius”. https://www.calflora.org/entry/observ.html$\#$srch=t\&taxon=Senecio+angustifolius\&cols=b\&inma=t\&y=36.7126\&x=-119.6126\&z=6\&cch=t\&inat=r.
Thompson, A., and W. Makepeace. 1983. “Short Note: Longevity of Buried Ragwort (Senecio Jacobaea L) Seed”. New Zealand Journal of Experimental Agriculture 11: 89-90. doi:10.1080/03015521.1983.10427734.
“Observation of Senecio Angustifolius \textendash Calflora”. n.d. https://www.calflora.org/entry/occdetail.html?seq_num=po145181.
15. Question 15
Yes
1
Low
I can find no documentation on germination of this specific species.
However, these papers which are for different Senecio shrubby and similar species (S. jacobaea) and each show high germination of seeds, greater than 25% after one year. It is speculative that this species may also has have high germination as well, but it is reasonable. (Thompson, A) (Anonymous)
Without specific documentation of this species answering Yes, but with Low confidence.
However, these papers which are for different Senecio shrubby and similar species (S. jacobaea) and each show high germination of seeds, greater than 25% after one year. It is speculative that this species may also has have high germination as well, but it is reasonable. (Thompson, A) (Anonymous)
Without specific documentation of this species answering Yes, but with Low confidence.
Thompson, A., and W. Makepeace. 1983. “Short Note: Longevity of Buried Ragwort (Senecio Jacobaea L) Seed”. New Zealand Journal of Experimental Agriculture 11: 89-90. doi:10.1080/03015521.1983.10427734.
“The Establishment of Seedlings from Primary and Regrowth Seeds of Ragwort (Senecio Jacobaea) on JSTOR”. n.d. https://www.jstor.org/stable/2259781$\#$metadata_info_tab_contents.
16. Question 16
Yes
1
High
Little published information. One Calflora record mentions a 4-5 year old plant in seed. (Calflora. Observation Search)
Another Calflora record documents abundant seed in a two to three year old plant. (Observation of Senecio angustifolius – Calflora)
This offers good information and warrants a "yes" answer for a woody plant, with a "high" confidence.
Another Calflora record documents abundant seed in a two to three year old plant. (Observation of Senecio angustifolius – Calflora)
This offers good information and warrants a "yes" answer for a woody plant, with a "high" confidence.
Calflora,. 2022. “Observation Search - Senecio Angustifolius”. https://www.calflora.org/entry/observ.html$\#$srch=t\&taxon=Senecio+angustifolius\&cols=b\&inma=t\&y=36.7126\&x=-119.6126\&z=6\&cch=t\&inat=r.
“Observation of Senecio Angustifolius \textendash Calflora”. n.d. https://www.calflora.org/entry/occdetail.html?seq_num=po145181.
17. Question 17
Yes
1
Very High
Seed production is likely most or all of the year as referenced by several sources:
"It germinates and grows throughout the year (unlike most other weeds, which are highly seasonal), and is therefore more difficult to control". (Senecio a. as a source . . .)
Flowering "all months" in CA (Simpson et al)
Calflora lists a flowering period of April through November, which would imply well over three months of seed production. (Calflora)
CCH records list flowering between the months of April and Nov., also implying well over three months of seed production. (CCH2)
"It germinates and grows throughout the year (unlike most other weeds, which are highly seasonal), and is therefore more difficult to control". (Senecio a. as a source . . .)
Flowering "all months" in CA (Simpson et al)
Calflora lists a flowering period of April through November, which would imply well over three months of seed production. (Calflora)
CCH records list flowering between the months of April and Nov., also implying well over three months of seed production. (CCH2)
Simpson, Michael S., and Ron Vanderhoff. (2023) 2022. “Taxonomic Identity of a Recently Naturalized Senecio Species in California”. Madrono. https://doi.org/10.3120/0024-9637-69.3.286.
“CCH2 Portal Collections Results for Senecio Angustifolia Accessed 9-2022”. 2022. https://www.cch2.org/portal/collections/listtabledisplay.php.
Calflora,. 2022. “Observation Search - Senecio Angustifolius”. https://www.calflora.org/entry/observ.html$\#$srch=t\&taxon=Senecio+angustifolius\&cols=b\&inma=t\&y=36.7126\&x=-119.6126\&z=6\&cch=t\&inat=r.
Van Wyk, B.E., M.A. Stander, and H.S. Long. 2017. “Senecio Angustifolius As the Major Source of Pyrrolizidine Alkaloid Contamination of Rooibos Tea (Aspalathus Linearis)”. South African Journal of Botany 110: 124-31. doi:10.1016/j.sajb.2017.01.013.
18. Question 18
No
0
Low
No specific documentation. However, no evidence of bristles or appendages on the seed (to attach to clothing, equipment, fur, etc.) and no indication of an attachment structure of pappus. Would make this method of dispersal unlikely.
Further, its pattern of occurrence in California seems as likely or likelier to come from animal-mediated or human dispersal. In California, it is present in dry canyons that are animal (and human) corridors as well as areas where wind or water could disperse them. These modes of dispersal are all inference but potential. It's mode of transport in Southern CA in fairly widely scattered populations, some separated by 35 km (CCH2 Portal), is a bit mysterious.
Further, its pattern of occurrence in California seems as likely or likelier to come from animal-mediated or human dispersal. In California, it is present in dry canyons that are animal (and human) corridors as well as areas where wind or water could disperse them. These modes of dispersal are all inference but potential. It's mode of transport in Southern CA in fairly widely scattered populations, some separated by 35 km (CCH2 Portal), is a bit mysterious.
“CCH2 Portal Collections Results for Senecio Angustifolia Accessed 9-2022”. 2022. https://www.cch2.org/portal/collections/listtabledisplay.php.
19. Question 19
Yes
1
Medium
Little if any specific documentation. Presumed dispersal by water from its occurrences in CA that are well correlated with washes and water corridors. (CCH2) (Calflora)
The achenes of the species are attached to a long pappus as seen in photographs (Calflora). However, the pappus does not appear to be feathery or plumose, which would make wind dispersal limited over long distances. The similar species, S. jacobaea, which has a similar pappus does not disperse seeds beyond 20 m. (McEvoy, P.B.)
Likely water dispersal as pappus and seeds should be able to float, a trait of S. jacobaea dispersal. (McEvoy, P.B.)
Answering yes, based upon likelihood of water dispersal and likely at least short distance wind dispersal.
The achenes of the species are attached to a long pappus as seen in photographs (Calflora). However, the pappus does not appear to be feathery or plumose, which would make wind dispersal limited over long distances. The similar species, S. jacobaea, which has a similar pappus does not disperse seeds beyond 20 m. (McEvoy, P.B.)
Likely water dispersal as pappus and seeds should be able to float, a trait of S. jacobaea dispersal. (McEvoy, P.B.)
Answering yes, based upon likelihood of water dispersal and likely at least short distance wind dispersal.
“CCH2 Portal Collections Results for Senecio Angustifolia Accessed 9-2022”. 2022. https://www.cch2.org/portal/collections/listtabledisplay.php.
Calflora,. 2022. “Observation Search - Senecio Angustifolius”. https://www.calflora.org/entry/observ.html$\#$srch=t\&taxon=Senecio+angustifolius\&cols=b\&inma=t\&y=36.7126\&x=-119.6126\&z=6\&cch=t\&inat=r.
2022. “INaturalist Observations: Senecio Angustifolius”. https://www.inaturalist.org/observations?place_id=any\&taxon_id=594182.
McEvoy, P.B., and C.S. Cox. 1987. “Wind Dispersal Distances in Dimorphic Achenes of Ragwort, Senecio Jacobaea”. Ecology 68: 2006-15.
20. Question 20
No
0
Low
A thorough paper about S. angustifolius invasion in agricultural South African tea plantations makes several references to the species invading these plantations. However, the contamination of the tea harvest only references contamination via chemical soil properties and the accumulation of toxins from the Senecio via soil, not seed. The paper stops short of saying the seed is present in the harvest and thus dispersed during harvest. (Senecio a. as the source . . .)
In California the known populations are rather widely scattered, with San Diego populations separated from Orange County populations by 20 miles. Within the San Diego occurrences, populations are as much as 5-10 miles separated, and in Orange County they are separated by 2 miles. (CCH2)
The question asks if long-distance dispersal is "frequent", which it does not seem to be, it is certainly happening, and quite possibly via people, clothes or footwear. How the plant moved from its native South Africa to USMC Camp Pendleton is possible via equipment, vehicles or clothing. However, this is speculative and warrants the Low confidence scoring.
In California the known populations are rather widely scattered, with San Diego populations separated from Orange County populations by 20 miles. Within the San Diego occurrences, populations are as much as 5-10 miles separated, and in Orange County they are separated by 2 miles. (CCH2)
The question asks if long-distance dispersal is "frequent", which it does not seem to be, it is certainly happening, and quite possibly via people, clothes or footwear. How the plant moved from its native South Africa to USMC Camp Pendleton is possible via equipment, vehicles or clothing. However, this is speculative and warrants the Low confidence scoring.
Van Wyk, B.E., M.A. Stander, and H.S. Long. 2017. “Senecio Angustifolius As the Major Source of Pyrrolizidine Alkaloid Contamination of Rooibos Tea (Aspalathus Linearis)”. South African Journal of Botany 110: 124-31. doi:10.1016/j.sajb.2017.01.013.
“CCH2 Portal Collections Results for Senecio Angustifolia Accessed 9-2022”. 2022. https://www.cch2.org/portal/collections/listtabledisplay.php.
Evaluation Notes
These is a scarcity of published date about this species natural history or invasiveness, making several of these questions either unanswered or with a low confidence score. Outside of its native South Africa, California appears to be the only location the species has naturalized, making us perhaps an early indicator for other similar climate areas of the world.
Briefly mentioned in Questions 1, 2, 3, and 4 are what I am considering dubious occurrence records in Mexico, Germany, Spain, and Taiwan:
Outside of its native range in South Africa, there are eight georeferenced occurences on GBIF from Mexico. Each of these are +- in the central or the Northern Central portion of the country, outside of any climate match to California. Two of the occurrences indicate "abundant" (at two different locales) and "dominant" at the same site and date (1990). Another collection (1973) many miles away also indicates "dominant". One other unrelated occurrence indicates "scarce". Others have no abundance information. (GBIF)
A very brief mention of Senecio angustifolius in Mexico is in a research paper discussing a co-occuring plant. It is mentioned as a component of the "shrub stratum" in an area about 125km NE of Mexico City (in a non-climate matched area). (Forest Science)
However, all of these Mexican occurrences are suspect. Based on date, institution, and location, collections by Tlapa Almonte appear to be a match to locality for Senecio cinerarioides collections on SEINet on that date. The collection by Rodriguez from 1986 also appears to match another specimen identified as S. cinerarioides on SEINet. I suspect at least some or all of these collections were, or will be later redetermined as S. cinerarioides, not angustifolius. (SEINet)
Two occurences in Germany are without any abundance information or details and are inconclusive.
A single very old record (1890) from Spain and a 1932 record from Taiwan are also inconclusive, with no additional information. The former could refer to a different species. (GBIF)
Total PRE Score
13
20
70
