Drought and Phytophthora Are Associated With the Decline of Oak Species in Southern Italy
Forest decline induced by climate change is a global phenomenon that affects many tree species, mainly in drought-prone areas as the Mediterranean region. In southern Italy, several oak species have shown decline symptoms and elevated mortality since the 2000s due to drought stress. However, it rema...
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| Format: | Article |
| Language: | English |
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Frontiers Media S.A.
2018-11-01
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| Series: | Frontiers in Plant Science |
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| Online Access: | https://www.frontiersin.org/article/10.3389/fpls.2018.01595/full |
| _version_ | 1828340850119147520 |
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| author | Michele Colangelo Michele Colangelo J. Julio Camarero Marco Borghetti Tiziana Gentilesca Jonàs Oliva Jonàs Oliva Miguel-Angel Redondo Francesco Ripullone |
| author_facet | Michele Colangelo Michele Colangelo J. Julio Camarero Marco Borghetti Tiziana Gentilesca Jonàs Oliva Jonàs Oliva Miguel-Angel Redondo Francesco Ripullone |
| author_sort | Michele Colangelo |
| collection | DOAJ |
| description | Forest decline induced by climate change is a global phenomenon that affects many tree species, mainly in drought-prone areas as the Mediterranean region. In southern Italy, several oak species have shown decline symptoms and elevated mortality since the 2000s due to drought stress. However, it remains to be answered whether decline occurred alone or whether a pathogen was also involved. To this aim, we compared two coexisting oak species in a forest located in southern Italy which are assumed to be less (Quercus cerris) and more tolerant to drought (Quercus pubescens). We sampled fifteen couples of neighboring declining (D) and non-declining (ND) trees of both species. Wood cores were taken from all trees to perform dendrochronological analyses to detect the decline onset and link it to potential climatic drivers. Carbon isotope ratios (d13C) were analyzed in wood of the two vigor classes to compare their water-use efficiency. Phytophthora presence was also assessed in soil samples from ten D-ND couples of trees per species. The oak species most affected by drought-induced decline in terms of leaf shedding and mortality was Q. cerris, i.e., the least tolerant to drought. In both species, the D trees showed a reduced growth rate compared with ND trees from 2000 onward when drought and warming intensified. Q. pubescens showed higher growth sensitivity to precipitation, temperature and drought than Q. cerris. This sensitivity to climate was magnified in D trees whose growth decreased in response to warm and dry conditions during the prior winter and the late summer. The Q. pubescens D trees were more efficient in their water use than ND trees before the growth divergence between D and ND trees amplified. In the studied area, Phytophthora quercina was isolated from 40% of the sampled trees, and tended to be more frequent amongst ND than amongst D trees. Our data suggests that droughts and warm summer conditions triggered oak decline. The high prevalence of P. quercina in the studied area warrants further study as a potential predisposing factor. |
| first_indexed | 2024-04-13T23:03:46Z |
| format | Article |
| id | doaj.art-1be34fddf57b4ead93044a411b2be1b2 |
| institution | Directory Open Access Journal |
| issn | 1664-462X |
| language | English |
| last_indexed | 2024-04-13T23:03:46Z |
| publishDate | 2018-11-01 |
| publisher | Frontiers Media S.A. |
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| series | Frontiers in Plant Science |
| spelling | doaj.art-1be34fddf57b4ead93044a411b2be1b22022-12-22T02:25:45ZengFrontiers Media S.A.Frontiers in Plant Science1664-462X2018-11-01910.3389/fpls.2018.01595412447Drought and Phytophthora Are Associated With the Decline of Oak Species in Southern ItalyMichele Colangelo0Michele Colangelo1J. Julio Camarero2Marco Borghetti3Tiziana Gentilesca4Jonàs Oliva5Jonàs Oliva6Miguel-Angel Redondo7Francesco Ripullone8School of Agricultural, Forest, Food and Environmental Sciences, University of Basilicata, Potenza, ItalyPyrenean Institute of Ecology (IPE-CSIC), Zaragoza, SpainPyrenean Institute of Ecology (IPE-CSIC), Zaragoza, SpainSchool of Agricultural, Forest, Food and Environmental Sciences, University of Basilicata, Potenza, ItalySchool of Agricultural, Forest, Food and Environmental Sciences, University of Basilicata, Potenza, ItalyDepartment of Crop and Forest Sciences, Agrotecnio Center, University of Lleida, Lleida, SpainDepartment of Forest Mycology and Plant Pathology, Swedish University of Agricultural Sciences, Uppsala, SwedenDepartment of Forest Mycology and Plant Pathology, Swedish University of Agricultural Sciences, Uppsala, SwedenSchool of Agricultural, Forest, Food and Environmental Sciences, University of Basilicata, Potenza, ItalyForest decline induced by climate change is a global phenomenon that affects many tree species, mainly in drought-prone areas as the Mediterranean region. In southern Italy, several oak species have shown decline symptoms and elevated mortality since the 2000s due to drought stress. However, it remains to be answered whether decline occurred alone or whether a pathogen was also involved. To this aim, we compared two coexisting oak species in a forest located in southern Italy which are assumed to be less (Quercus cerris) and more tolerant to drought (Quercus pubescens). We sampled fifteen couples of neighboring declining (D) and non-declining (ND) trees of both species. Wood cores were taken from all trees to perform dendrochronological analyses to detect the decline onset and link it to potential climatic drivers. Carbon isotope ratios (d13C) were analyzed in wood of the two vigor classes to compare their water-use efficiency. Phytophthora presence was also assessed in soil samples from ten D-ND couples of trees per species. The oak species most affected by drought-induced decline in terms of leaf shedding and mortality was Q. cerris, i.e., the least tolerant to drought. In both species, the D trees showed a reduced growth rate compared with ND trees from 2000 onward when drought and warming intensified. Q. pubescens showed higher growth sensitivity to precipitation, temperature and drought than Q. cerris. This sensitivity to climate was magnified in D trees whose growth decreased in response to warm and dry conditions during the prior winter and the late summer. The Q. pubescens D trees were more efficient in their water use than ND trees before the growth divergence between D and ND trees amplified. In the studied area, Phytophthora quercina was isolated from 40% of the sampled trees, and tended to be more frequent amongst ND than amongst D trees. Our data suggests that droughts and warm summer conditions triggered oak decline. The high prevalence of P. quercina in the studied area warrants further study as a potential predisposing factor.https://www.frontiersin.org/article/10.3389/fpls.2018.01595/fullcarbon isotopesdendroecologydrought stressforest diebackPhytophthora speciesQuercus cerris |
| spellingShingle | Michele Colangelo Michele Colangelo J. Julio Camarero Marco Borghetti Tiziana Gentilesca Jonàs Oliva Jonàs Oliva Miguel-Angel Redondo Francesco Ripullone Drought and Phytophthora Are Associated With the Decline of Oak Species in Southern Italy Frontiers in Plant Science carbon isotopes dendroecology drought stress forest dieback Phytophthora species Quercus cerris |
| title | Drought and Phytophthora Are Associated With the Decline of Oak Species in Southern Italy |
| title_full | Drought and Phytophthora Are Associated With the Decline of Oak Species in Southern Italy |
| title_fullStr | Drought and Phytophthora Are Associated With the Decline of Oak Species in Southern Italy |
| title_full_unstemmed | Drought and Phytophthora Are Associated With the Decline of Oak Species in Southern Italy |
| title_short | Drought and Phytophthora Are Associated With the Decline of Oak Species in Southern Italy |
| title_sort | drought and phytophthora are associated with the decline of oak species in southern italy |
| topic | carbon isotopes dendroecology drought stress forest dieback Phytophthora species Quercus cerris |
| url | https://www.frontiersin.org/article/10.3389/fpls.2018.01595/full |
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