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Derya Esen - One of the best experts on this subject based on the ideXlab platform.
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effect of invasive Rhododendron ponticum l on natural regeneration and structure of fagus orientalis lipsky forests in the black sea region
Forests, 2020Co-Authors: Zdeněk Vacek, Derya Esen, Stanislav Vacek, Oktay Yildiz, Jan Kral, Josef GalloAbstract:Biological invasions threaten global biodiversity and forest ecosystems; therefore, it is necessary to use appropriate strategies for combating the spread of invasive species. Natural regeneration of eastern beech (Fagus orientalis Lipsky) is considerably limited by an aggressive invasive shrub, pontic Rhododendron (Rhododendron ponticum L.), in the Black Sea Region of Turkey. Therefore, the future character of the region’s forests is uncertain. The aim of this research was to evaluate the structure of beech forests with different management regimes of rhododedron and to determine the interaction among tree layer, Rhododendron cover, and natural regeneration in Duzce Province using the FieldMap technology. The following variants of forests were compared: without intervention (control) and three and six years after Rhododendron clearance. The results showed that tree density ranged between 175–381 trees ha−1 and stand volume between 331–589 m3 ha−1. The horizontal structure of the tree layer was mostly random, and the spatial pattern of natural regeneration was aggregated. Recruit density and height in the beech stands were significantly differentiated due to the influence of presence or absence of invasive Rhododendron. Rhododendron cover ranged between 81%–97%, and woody stems amounted to 72,178–86,884 ha−1 in unmanaged forests. Canopy in the overstory did not have a significant effect on the density of regeneration and Rhododendron cover. Tree layer had a significant negative influence on natural regeneration within a 4 m radius on the plots without Rhododendron. However, on the plots with dense Rhododendron cover, tree layer had a positive influence on regeneration within a 1.5 m radius. Natural regeneration density was significantly higher when Rhododendron was cleared than the plots without intervention. On the plots without woody clearance, there was an insufficient regeneration (113–619 recruits ha−1); however, they had higher mean height compared to the sites without Rhododendron. After three and six years of Rhododendron clearance, the numbers of recruits in natural regeneration were 63,981 ha−1 and 105,075 ha−1, respectively. In conclusion, invasive spread of Rhododendron was a limiting factor of the prosperous regeneration and tree species diversity, and manual clearance of Rhododendron is recommended in managed beech forests of the study region.
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soil and site factors influencing purple flowered Rhododendron Rhododendron ponticum l and eastern beech forests fagus orientalis lipsky in turkey
Forest Ecology and Management, 2004Co-Authors: Derya Esen, Shepard M Zedaker, Jeffrey L Kirwan, Paul P MouAbstract:Abstract Eastern beech (Fagus orientalis Lipsky) is the major timber species growing in the Black Sea Region (BSR) forests of Turkey. Purple-flowered Rhododendron (Rhododendron ponticum L.) is native to the region and currently dominates the understory of almost the entire eastern beech forest, reducing tree regeneration and growth. An aging beech overstory with little or no regeneration is the current state of most of the beech–Rhododendron forests. We examined whether and how major environmental and disturbance factors have influenced the distribution and growth of Rhododendron and beech in the region by determining the effects of canopy light, topography (aspect, elevation, slope), soil (moisture content, depth, texture, pH), and disturbance (anthropogenic and fire) on the establishment, abundance, and growth rate of Rhododendron and beech in two Rhododendron-invaded beech forests with different anthropogenic disturbance histories in the western BSR. We also studied the age and size structures of current beech stands and Rhododendron to understand their origins and their future under varying levels of anthropogenic pressure. The two sites had different stem-size class distributions. A weak relationship was found between diameter at breast height and age for beech, whereas there was a strong correlation between groundline diameter and age for Rhododendron. The Rhododendron understory was established after the beech overstory. Charcoal-density analysis and beech stem ages suggested that fire has not been a major regenerative disturbance for these sites, at least in the past 150–200 years. Rhododendron reduced both beech regeneration and long-term growth. The Rhododendron-population structure suggested continuing domination in the near future, with increasing density and proportion of small stems. Soil moisture was an important environmental factor affecting Rhododendron and beech abundance and growth. Adequate soil aeration was critical for Rhododendron. Use of foliar herbicides with burning during tree-regeneration efforts will probably provide greater success on Rhododendron control. Establishing mixed beech-conifer stands might lower expansion of current and future Rhododendron populations in the long term.
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control of Rhododendron Rhododendron ponticum and r flavum in the eastern beech fagus orientalis forests of turkey
New Forests, 2004Co-Authors: Derya Esen, Shepard M ZedakerAbstract:Because purple-flowered Rhododendron (Rhododendron ponticum L.) and yellow-flowered Rhododendron (R. flavum Don.) significantly reduce seedling growth and regeneration of eastern beech (Fagus orientalis Lipsky) as well as local floristic diversity in northern Turkey, effective and cost-efficient woody control is needed. Various manual (cut and grub) and herbicide (foliar and cut-stump spray) woody control techniques were used in two different beech-Rhododendron sites in the Black Sea Region (BSR) of Turkey. Two years later, biological and economic effectiveness were substantially greater with foliar-applied herbicide and grubbing treatments than with the cutting, cut-stump, and check treatments. Yet, grubbing showed a great potential for sprout crown reduction. Cut-stump spray was intermediate in effectiveness. Cutting had the least woody control and economic effectiveness among all of the treatments. Foliar-applied Arsenal SL (imazapyr) had significantly greater Rhododendron control than foliar-appliied Garlon 4 (triclopyr ester). Increasing rates did not enhance herbicide efficacy. Reducing rates further may provide the same level of control at less cost.
Larrue Sébastien - One of the best experts on this subject based on the ideXlab platform.
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Effets de l’arbuste envahissant Rhododendron ponticum L. sur quelques espèces indigènes de l’île de Rùm (Ecosse du nord-ouest)
Société nationale de protection de la nature, 2015Co-Authors: Arthur Messerli, Larrue SébastienAbstract:International audienceIntroduit dans les îles britanniques en 1763 pour sa valeur ornementale, Rhododendron ponticum (L.) est aujourd’hui un arbuste naturalisé dans tout le Royaume-Uni. Cette espèce est considérée comme l’une des plus envahissantes de Grande-Bretagne. Cette étude tente in situ de mettre en évidence les effets de Rhododendron ponticum sur quelques espèces indigènes de l’île de Rùm (Nord-Ouest de l’Écosse, Grande Bretagne) où les gestionnaires se sont notamment engagés dans des programmes de reboisement en espèces ligneuses indigènes. Nous avons comparé la diversité végétale (i.e., la richesse spécifique, l’abondance, et les indices de diversité de Shannon, Simpson et d’équitabilité) dans (1) des placettes de 100 m² situées en landes envahies et non envahies par Rhododendron ponticum, et (2) des îlots de sous-bois formés par des individus d’Ilex aquifolium (indigène) versus Rhododendron ponticum (introduite). Les placettes envahies par Rhododendron ponticum présentent globalement des indices de Shannon, Simpson et une équitabilité plus faibles. Dans les îlots, on observe la même tendance, les indices de diversité sont plus faibles sous les îlots à Rhododendron ponticum que sous ceux à Ilex aquifolium. Ces résultats laissent à penser que Rhododendron ponticum perturbe l’établissement des espèces indigènes avec notamment une moindre abondance des ptéridophytes telles que Dryopteris dilatata et Dryopteris filix-mas. Par ailleurs, les îlots à Ilex aquifolium présentent une diminution significative dans l’abondance de Rhododendron ponticum en sous-bois. Ilex aquifolium devrait donc accompagner les programmes de reboisement en espèces indigènes afin de diminuer l’invasion de Rhododendron ponticum en sous-bois
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EFFETS DE L’ARBUSTE ENVAHISSANT Rhododendron PONTICUM L. SUR QUELQUES ESPECES INDIGENES DE L’ILE DE RÙM (ÉCOSSE DU NORD-OUEST)
Société nationale de protection de la nature, 2015Co-Authors: Messerli Arthur, Larrue SébastienAbstract:International audienceEffects of the invasive shrub Rhododendron ponticum L. on some native species on Rùm Island (Northwest Scotland).-In 1763, the shrub Rhododendron ponticum L. has been introduced on the British Isles for its ornamental value. The species is currently naturalized in many islands and is considered as one of the most invasive species of Great Britain. This study highlights the effects of Rhododendron ponticum on some native species on the Isle of Rùm (Northwest Scotland, Great Britain) in the frame of reforestation programs with native woody species. We compared plant diversity, species richness, abundance, and diversity indices in (1) 100 m² plots located in both invaded and not invaded heathlands by Rhododendron ponticum, and (2) under thickets of either Ilex aquifolium (indigenous species) or Rhododendron ponticum (invasive species) in understory environment. Our results show that plant diversity decreases with Rhododendron ponticum establishment and particularly for Dryopteris dilatata and Dryopteris filix-mas in the understory. Plots invaded by Rhododendron ponticum have lower diversity indices and these indices are greater under Ilex aquifolium thickets than those of Rhododendron ponticum in the understory. These findings lead us to consider that Rhododendron ponticum decreases native species diversity on the Isle of Rùm. Furthermore, our results also show that the indigenous species Ilex aquifolium seems to reduce the abundance of Rhododendron ponticum in the understory environment. We suggest that Ilex aquifolium can be viewed as a key species in reforestation programs against Rhododendron ponticum invasion on the Isle of Rùm.RÉSUMÉ. Introduit dans les îles britanniques en 1763 pour sa valeur ornementale, Rhododendron ponticum (L.) est aujourd'hui un arbuste naturalisé dans tout le Royaume-Uni. Cette espèce est considérée comme l'une des plus envahissantes de Grande-Bretagne. Cette étude tente in situ de mettre en évidence les effets de Rhododendron ponticum sur quelques espèces indigènes de l'île de Rùm (Nord-Ouest de l'Écosse, Grande Bretagne) où les gestionnaires se sont notamment engagés dans des programmes de reboisement en espèces ligneuses indigènes. Nous avons comparé la diversité végétale (i.e., la richesse spécifique, l'abondance, et les indices de diversité de Shannon, Simpson et d'équitabilité) dans (1) des placettes de 100 m² situées en landes envahies et non envahies par Rhododendron ponticum, et (2) des îlots de sous-bois formés par des individus d'Ilex aquifolium (indigène) versus Rhododendron ponticum (introduite). Les placettes envahies par Rhododendron ponticum présentent globalement des indices de Shannon, Simpson et une équitabilité plus faibles. Dans les îlots, on observe la même tendance, les indices de diversité sont plus faibles sous les îlots à Rhododendron ponticum que sous ceux à Ilex aquifolium. Ces résultats laissent à penser que Rhododendron ponticum perturbe l'établissement des espèces indigènes avec notamment une moindre abondance des ptéridophytes telles que Dryopteris dilatata et Dryopteris filix-mas. Par ailleurs, les îlots à Ilex aquifolium présentent une diminution significative dans l'abondance de Rhododendron ponticum en sous-bois. Ilex aquifolium devrait donc accompagner les programmes de reboisement en espèces indigènes afin de diminuer l'invasion de Rhododendron ponticum en sous-bois
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Effects of the invasive shrub Rhododendron ponticum L. on some native species on Rùm Island (Northwest Scotland)
Société nationale de protection de la nature et d'acclimatation de France Paris (FRA), 2015Co-Authors: Messerli Arthur, Larrue SébastienAbstract:Introduit dans les îles britanniques en 1763 pour sa valeur ornementale, Rhododendron ponticum (L.) est aujourd’hui un arbuste naturalisé dans tout le Royaume-Uni. Cette espèce est considérée comme l’une des plus envahissantes de Grande-Bretagne. Cette étude tente in situ de mettre en évidence les effets de Rhododendron ponticum sur quelques espèces indigènes de l’île de Rùm (Écosse du Nord-Ouest, Grande Bretagne) où les gestionnaires se sont notamment engagés dans des programmes de reboisement en espèces ligneuses indigènes. Nous avons comparé la diversité végétale (i.e., la richesse spécifique, l’abondance, et les indices de diversité de Shannon, Simpson et d’équitabilité) dans (1) des placettes de 100 m² situées en landes envahies et non envahies par Rhododendron ponticum, et (2) des îlots de sous-bois formés par des individus d’Ilex aquifolium (indigène) versus Rhododendron ponticum (introduite). Les placettes envahies par Rhododendron ponticum présentent globalement des indices de Shannon, Simpson et une équitabilité plus faibles. Dans les îlots, on observe la même tendance, les indices de diversité sont plus faibles sous les îlots à Rhododendron ponticum que sous ceux à Ilex aquifolium. Ces résultats laissent à penser que Rhododendron ponticum perturbe l’établissement des espèces indigènes avec notamment une moindre abondance des ptéridophytes telles que Dryopteris dilatata et Dryopteris filix-mas. Par ailleurs, les îlots à Ilex aquifolium présentent une diminution significative dans l’abondance de Rhododendron ponticum en sous-bois. Ilex aquifolium devrait donc accompagner les programmes de reboisement en espèces indigènes afin de diminuer l’invasion de Rhododendron ponticum en sous-bois.In 1763, the shrub Rhododendron ponticum L. has been introduced on the British Isles for its ornamental value. The species is currently naturalized in many islands and is considered as one of the most invasive species of Great Britain. This study highlights the effects of Rhododendron ponticum on some native species on the Isle of Rùm (Northwest Scotland, Great Britain) in the frame of reforestation programs with native woody species. We compared plant diversity, species richness, abundance, and diversity indices in (1) 100 m² plots located in both invaded and not invaded heathlands by Rhododendron ponticum, and (2) under thickets of either Ilex aquifolium (indigenous species) or Rhododendron ponticum (invasive species) in understory environment. Our results show that plant diversity decreases with Rhododendron ponticum establishment and particularly for Dryopteris dilatata and Dryopteris filix-mas in the understory. Plots invaded by Rhododendron ponticum have lower diversity indices and these indices are greater under Ilex aquifolium thickets than those of Rhododendron ponticum in the understory. These findings lead us to consider that Rhododendron ponticum decreases native species diversity on the Isle of Rùm. Furthermore, our results also show that the indigenous species Ilex aquifolium seems to reduce the abundance of Rhododendron ponticum in the understory environment. We suggest that Ilex aquifolium can be viewed as a key species in reforestation programs against Rhododendron ponticum invasion on the Isle of Rùm
Paul P Mou - One of the best experts on this subject based on the ideXlab platform.
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soil and site factors influencing purple flowered Rhododendron Rhododendron ponticum l and eastern beech forests fagus orientalis lipsky in turkey
Forest Ecology and Management, 2004Co-Authors: Derya Esen, Shepard M Zedaker, Jeffrey L Kirwan, Paul P MouAbstract:Abstract Eastern beech (Fagus orientalis Lipsky) is the major timber species growing in the Black Sea Region (BSR) forests of Turkey. Purple-flowered Rhododendron (Rhododendron ponticum L.) is native to the region and currently dominates the understory of almost the entire eastern beech forest, reducing tree regeneration and growth. An aging beech overstory with little or no regeneration is the current state of most of the beech–Rhododendron forests. We examined whether and how major environmental and disturbance factors have influenced the distribution and growth of Rhododendron and beech in the region by determining the effects of canopy light, topography (aspect, elevation, slope), soil (moisture content, depth, texture, pH), and disturbance (anthropogenic and fire) on the establishment, abundance, and growth rate of Rhododendron and beech in two Rhododendron-invaded beech forests with different anthropogenic disturbance histories in the western BSR. We also studied the age and size structures of current beech stands and Rhododendron to understand their origins and their future under varying levels of anthropogenic pressure. The two sites had different stem-size class distributions. A weak relationship was found between diameter at breast height and age for beech, whereas there was a strong correlation between groundline diameter and age for Rhododendron. The Rhododendron understory was established after the beech overstory. Charcoal-density analysis and beech stem ages suggested that fire has not been a major regenerative disturbance for these sites, at least in the past 150–200 years. Rhododendron reduced both beech regeneration and long-term growth. The Rhododendron-population structure suggested continuing domination in the near future, with increasing density and proportion of small stems. Soil moisture was an important environmental factor affecting Rhododendron and beech abundance and growth. Adequate soil aeration was critical for Rhododendron. Use of foliar herbicides with burning during tree-regeneration efforts will probably provide greater success on Rhododendron control. Establishing mixed beech-conifer stands might lower expansion of current and future Rhododendron populations in the long term.
Helge Bruelheide - One of the best experts on this subject based on the ideXlab platform.
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invasibility or invasiveness effects of habitat genotype and their interaction on invasive Rhododendron ponticum populations
Biological Invasions, 2010Co-Authors: Alexandra Erfmeier, Helge BruelheideAbstract:The extent and nature of biological invasions are mainly influenced by either the genotype of the invading species, the suitability of the new habitat or by genotype-habitat interactions expressed in adaptations to the new environment. The relevance of these factors was assessed for the invasive evergreen shrub Rhododendron ponticum. Habitat characteristics of soil, climate and community properties were analysed in six native populations in both Georgia (Caucasus) and Spain and in six invasive ones in Ireland. Growth variables of Rhododendron individuals and seedling occurrences in the field served as response variables. We performed a reciprocal transplant experiment with Rhododendron cuttings and determined survival of transplants in all countries. Due to low survival rates in Georgia and Spain, vegetative increase was only analysed for Ireland. The Irish sites benefited from significantly higher nutrient supply than the Spanish and Georgian sites. We found both strong positive correlations of nutrient supply and negative correlations of seasonal temperature amplitude with growth variables of shoots and seedling density. Origin, target site and interaction effects were significant in the survival of transplanted Rhododendron individuals. The Irish site was more favorable for all genotypes, but the invasive genotypes did not perform better than the native ones. The total increase in shoot length of transplants in Ireland was highest in the Irish genotypes, which might suggest adaptation of the Irish populations to their new area. In conclusion, we found evidence for invasiveness of Irish Rhododendron ponticum populations, but only in the invaded habitat. Nonetheless, habitats in the new range also seem to be well suited to native Spanish populations, supporting the idea that invasibility of these new sites also contributes to Rhododendron invasion success.
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comparison of native and invasive Rhododendron ponticum populations growth reproduction and morphology under field conditions
Flora, 2004Co-Authors: Alexandra Erfmeier, Helge BruelheideAbstract:Summary The objective of this paper is to identify the factors that promote the invasiveness of Rhododendron ponticum L. by the means of comparative field observations. Rhododendron ponticum (Ericaceae) is an evergreen shrub with a natural distribution in the Mediterranean and Black Sea area and was introduced to the British Isles in 1763. Thenceforward, the species has been considered as a major threat to natural ecosystems there. We compared native and invasive populations of Rhododendron ponticum with respect to trait patterns that are associated with invasiveness. Six populations each in the natural part of its range, in Georgia (Caucasus) and Spain as well as six invasive ones in Ireland were examined with regard to biometrical, morphological and ecological characteristics. Invasive Irish populations differed from non-invasive ones mainly in growth patterns and showed much higher rates of annual shoot growth in the field and higher rates of seedling recruitment. In contrast, native Spanish populations were discriminated by their shape and age; whereas native Georgian Rhododendron, above all, showed distinctive leaf characteristics. In general, the relationship between Irish and Spanish populations was closer than to the Georgian ones. Our results suggest that both genotype and environment account for the trait pattern found in Irish populations. Differences in genetically fixed traits had a greater effect in morphological differences to Georgian provenances. In contrast, the invasive Irish Rhododendron were favoured by a more benign environment than the Spanish populations.
Shepard M Zedaker - One of the best experts on this subject based on the ideXlab platform.
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soil and site factors influencing purple flowered Rhododendron Rhododendron ponticum l and eastern beech forests fagus orientalis lipsky in turkey
Forest Ecology and Management, 2004Co-Authors: Derya Esen, Shepard M Zedaker, Jeffrey L Kirwan, Paul P MouAbstract:Abstract Eastern beech (Fagus orientalis Lipsky) is the major timber species growing in the Black Sea Region (BSR) forests of Turkey. Purple-flowered Rhododendron (Rhododendron ponticum L.) is native to the region and currently dominates the understory of almost the entire eastern beech forest, reducing tree regeneration and growth. An aging beech overstory with little or no regeneration is the current state of most of the beech–Rhododendron forests. We examined whether and how major environmental and disturbance factors have influenced the distribution and growth of Rhododendron and beech in the region by determining the effects of canopy light, topography (aspect, elevation, slope), soil (moisture content, depth, texture, pH), and disturbance (anthropogenic and fire) on the establishment, abundance, and growth rate of Rhododendron and beech in two Rhododendron-invaded beech forests with different anthropogenic disturbance histories in the western BSR. We also studied the age and size structures of current beech stands and Rhododendron to understand their origins and their future under varying levels of anthropogenic pressure. The two sites had different stem-size class distributions. A weak relationship was found between diameter at breast height and age for beech, whereas there was a strong correlation between groundline diameter and age for Rhododendron. The Rhododendron understory was established after the beech overstory. Charcoal-density analysis and beech stem ages suggested that fire has not been a major regenerative disturbance for these sites, at least in the past 150–200 years. Rhododendron reduced both beech regeneration and long-term growth. The Rhododendron-population structure suggested continuing domination in the near future, with increasing density and proportion of small stems. Soil moisture was an important environmental factor affecting Rhododendron and beech abundance and growth. Adequate soil aeration was critical for Rhododendron. Use of foliar herbicides with burning during tree-regeneration efforts will probably provide greater success on Rhododendron control. Establishing mixed beech-conifer stands might lower expansion of current and future Rhododendron populations in the long term.
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control of Rhododendron Rhododendron ponticum and r flavum in the eastern beech fagus orientalis forests of turkey
New Forests, 2004Co-Authors: Derya Esen, Shepard M ZedakerAbstract:Because purple-flowered Rhododendron (Rhododendron ponticum L.) and yellow-flowered Rhododendron (R. flavum Don.) significantly reduce seedling growth and regeneration of eastern beech (Fagus orientalis Lipsky) as well as local floristic diversity in northern Turkey, effective and cost-efficient woody control is needed. Various manual (cut and grub) and herbicide (foliar and cut-stump spray) woody control techniques were used in two different beech-Rhododendron sites in the Black Sea Region (BSR) of Turkey. Two years later, biological and economic effectiveness were substantially greater with foliar-applied herbicide and grubbing treatments than with the cutting, cut-stump, and check treatments. Yet, grubbing showed a great potential for sprout crown reduction. Cut-stump spray was intermediate in effectiveness. Cutting had the least woody control and economic effectiveness among all of the treatments. Foliar-applied Arsenal SL (imazapyr) had significantly greater Rhododendron control than foliar-appliied Garlon 4 (triclopyr ester). Increasing rates did not enhance herbicide efficacy. Reducing rates further may provide the same level of control at less cost.
