The allelopathic, adhesive, hydrophobic and toxic latex of Euphorbia species is the cause of fairy circles investigated at several locations in Namibia
Abstract Background In this multidisciplinary study we present soil chemical, phytochemical and GIS spatial patterning evidence that fairy circles studied in three separate locations of Namibia may be caused by Euphorbia species. Results We show that matrix sand coated with E. damarana latex resulte...
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| Format: | Article |
| Language: | English |
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BMC
2020-08-01
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| Series: | BMC Ecology |
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| Online Access: | http://link.springer.com/article/10.1186/s12898-020-00313-7 |
| _version_ | 1830144330841456640 |
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| author | J. J. Marion Meyer Christiaan E. Schutte Jan W. Hurter Nicole S. Galt Petunia Degashu Greg Breetzke Denis Baranenko Nicole L. Meyer |
| author_facet | J. J. Marion Meyer Christiaan E. Schutte Jan W. Hurter Nicole S. Galt Petunia Degashu Greg Breetzke Denis Baranenko Nicole L. Meyer |
| author_sort | J. J. Marion Meyer |
| collection | DOAJ |
| description | Abstract Background In this multidisciplinary study we present soil chemical, phytochemical and GIS spatial patterning evidence that fairy circles studied in three separate locations of Namibia may be caused by Euphorbia species. Results We show that matrix sand coated with E. damarana latex resulted in faster water-infiltration rates. GC-MS analyses revealed that soil from fairy circles and from under decomposing E. damarana plants are very similar in phytochemistry. E. damarana and E. gummifera extracts have a detrimental effect on bacteria isolated from the rhizosphere of Stipagrostis uniplumis and inhibit grass seed germination. Several compounds previously identified with antimicrobial and phytotoxic activity were also identified in E. gummifera. GIS analyses showed that perimeter sizes and spatial characteristics (Voronoi tessellations, distance to nearest neighbour ratio, pair correlation function and L-function) of fairy circles are similar to those of fairy circles co-occurring with E. damarana (northern Namibia), and with E. gummifera (southern Namibia). Historical aerial imagery showed that in a population of 406 E. gummifera plants, 134 were replaced by fairy circles over a 50-year period. And finally, by integrating rainfall, altitude and landcover in a GIS-based site suitability model, we predict where fairy circles should occur. The model largely agreed with the distribution of three Euphorbia species and resulted in the discovery of new locations of fairy circles, in the far southeast of Namibia and part of the Kalahari Desert of South Africa. Conclusions It is proposed that the allelopathic, adhesive, hydrophobic and toxic latex of E. damarana, E. gummifera, and possibly other species like E. gregaria, is the cause of the fairy circles of Namibia in the areas investigated and possibly in all other areas as well. |
| first_indexed | 2024-12-17T10:04:24Z |
| format | Article |
| id | doaj.art-3eec57df6cac474d9aba3a58ed891ba6 |
| institution | Directory Open Access Journal |
| issn | 1472-6785 |
| language | English |
| last_indexed | 2024-12-17T10:04:24Z |
| publishDate | 2020-08-01 |
| publisher | BMC |
| record_format | Article |
| series | BMC Ecology |
| spelling | doaj.art-3eec57df6cac474d9aba3a58ed891ba62022-12-21T21:53:11ZengBMCBMC Ecology1472-67852020-08-0120112310.1186/s12898-020-00313-7The allelopathic, adhesive, hydrophobic and toxic latex of Euphorbia species is the cause of fairy circles investigated at several locations in NamibiaJ. J. Marion Meyer0Christiaan E. Schutte1Jan W. Hurter2Nicole S. Galt3Petunia Degashu4Greg Breetzke5Denis Baranenko6Nicole L. Meyer7Department of Plant and Soil Sciences, University of PretoriaDepartment of Plant and Soil Sciences, University of PretoriaDepartment of Plant and Soil Sciences, University of PretoriaDepartment of Plant and Soil Sciences, University of PretoriaDepartment of Plant and Soil Sciences, University of PretoriaDepartment of Geography, Geoinformatics and Meteorology, University of PretoriaITMO UniversityDepartment of Plant and Soil Sciences, University of PretoriaAbstract Background In this multidisciplinary study we present soil chemical, phytochemical and GIS spatial patterning evidence that fairy circles studied in three separate locations of Namibia may be caused by Euphorbia species. Results We show that matrix sand coated with E. damarana latex resulted in faster water-infiltration rates. GC-MS analyses revealed that soil from fairy circles and from under decomposing E. damarana plants are very similar in phytochemistry. E. damarana and E. gummifera extracts have a detrimental effect on bacteria isolated from the rhizosphere of Stipagrostis uniplumis and inhibit grass seed germination. Several compounds previously identified with antimicrobial and phytotoxic activity were also identified in E. gummifera. GIS analyses showed that perimeter sizes and spatial characteristics (Voronoi tessellations, distance to nearest neighbour ratio, pair correlation function and L-function) of fairy circles are similar to those of fairy circles co-occurring with E. damarana (northern Namibia), and with E. gummifera (southern Namibia). Historical aerial imagery showed that in a population of 406 E. gummifera plants, 134 were replaced by fairy circles over a 50-year period. And finally, by integrating rainfall, altitude and landcover in a GIS-based site suitability model, we predict where fairy circles should occur. The model largely agreed with the distribution of three Euphorbia species and resulted in the discovery of new locations of fairy circles, in the far southeast of Namibia and part of the Kalahari Desert of South Africa. Conclusions It is proposed that the allelopathic, adhesive, hydrophobic and toxic latex of E. damarana, E. gummifera, and possibly other species like E. gregaria, is the cause of the fairy circles of Namibia in the areas investigated and possibly in all other areas as well.http://link.springer.com/article/10.1186/s12898-020-00313-7Fairy circlesNamibiaEuphorbiaLatexAllelopathySpatial pattern |
| spellingShingle | J. J. Marion Meyer Christiaan E. Schutte Jan W. Hurter Nicole S. Galt Petunia Degashu Greg Breetzke Denis Baranenko Nicole L. Meyer The allelopathic, adhesive, hydrophobic and toxic latex of Euphorbia species is the cause of fairy circles investigated at several locations in Namibia BMC Ecology Fairy circles Namibia Euphorbia Latex Allelopathy Spatial pattern |
| title | The allelopathic, adhesive, hydrophobic and toxic latex of Euphorbia species is the cause of fairy circles investigated at several locations in Namibia |
| title_full | The allelopathic, adhesive, hydrophobic and toxic latex of Euphorbia species is the cause of fairy circles investigated at several locations in Namibia |
| title_fullStr | The allelopathic, adhesive, hydrophobic and toxic latex of Euphorbia species is the cause of fairy circles investigated at several locations in Namibia |
| title_full_unstemmed | The allelopathic, adhesive, hydrophobic and toxic latex of Euphorbia species is the cause of fairy circles investigated at several locations in Namibia |
| title_short | The allelopathic, adhesive, hydrophobic and toxic latex of Euphorbia species is the cause of fairy circles investigated at several locations in Namibia |
| title_sort | allelopathic adhesive hydrophobic and toxic latex of euphorbia species is the cause of fairy circles investigated at several locations in namibia |
| topic | Fairy circles Namibia Euphorbia Latex Allelopathy Spatial pattern |
| url | http://link.springer.com/article/10.1186/s12898-020-00313-7 |
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