<p><em>Aim of study:</em><strong> </strong>Being the longest-lived of all European trees, capable of living significantly over 2,000 years, yew is highly likely to be negatively affected by climate change; this paper explores the changes in distribution and abundance. </p><p><em>Main results:</em> Yew is unlikely to migrate north due to its slow rate of invasion, its disjunct soil needs and an inability to cope with the expected rate of climate change. It will, however, retreat from the southern end of its range in Spain due to increased evapotranspiration allied to reduced rainfall. In the south, increased drought will be exacerbated by extreme drought and increased fire frequency. In drier areas at the northern edge of its range, yew will decline where growing on well-drained limestone outcrops with little shelter from the sun (increased evaporation) and reduced water availability due to limited root spread. On wetter northern sites, yew should find better climatic conditions but will be slow to invade new areas due to poorer reproduction affected by reduced pollen production, population fragmentation and limited seed movement. Overall, without our intervention, yew will survive by inertia in the short-term but eventual become extinct in most areas. Of equal concern will be the loss of old veteran individuals and associated biodiversity. </p><p><em>Research highlights:</em> There is an urgent need for interventionist management for both old and young trees, relieving the stress on old veteran trees, and planting and maintaining seedlings through vulnerable young age. A list of management priorities is given.</p><p><strong>Keywords: </strong>Yew; <em>Taxus baccata</em>; Temperature; Precipitation; Seedlings; Bioclimate envelope; Species range.</p>
<p class="Cos"><em>Aim of study: </em>In the Mediterranean region, yew (<em>Taxus baccata</em> L.) usually grows with other tree species in mixed forests. Yew recruitment and juvenile growth may depend on the structure of the forest and the net balance between competition for soil water and nutrients with neighbors and facilitation that these neighbors exert by protecting the plants from direct sun exposure. This study aims, at a regional scale, to analyze the structure of forests containing yew, and, on an individual level, to analyze the effect of the surrounding vegetation structure on the performance of yew juveniles.</p><p class="Cos"><em>Area of study: </em>The structural typologies of yew populations were defined based on field inventories conducted in 55 plots distributed in 14 localities in the North-Eastern (NE) Iberian Peninsula, covering a wide range of yew distribution in the area. In a second step, an analysis of neighboring species' effects on juveniles was conducted based on the data from 103 plots centered in yew juveniles in five localities.<em></em></p><p class="Cos"><em>Main Results: </em>A cluster analysis classified the inventoried stands into four forest structural types: two multi-stratified forests with scattered yew and two yew groves. Multiple regression modeling showed that the δ<sup>13</sup>C measured in last year's leaves positively relates to the basal area of conifer neighbors, but negatively with the cover of the yew crown by other trees.</p><p class="Cos"><em>Research highlights: </em>At a stand-level, the density of recruits and juveniles (625 ± 104 recruits ha<sup>-1</sup>, 259 ± 55 juveniles ha<sup>-1</sup>) in mixed forests was found to be higher than that on yew dominant stands (181 ± 88 recruits ha<sup>-1</sup> and 57 ± 88 juveniles ha<sup>-1</sup>). At an individual-level, the water stress (estimated from leaf δ<sup>13</sup>C) of yew juveniles seems alleviated by the crown cover by neighbors while it increases with the basal area of conifers. Yew conservation should focus on selective felling for the reduction of basal area of neighbors surrounding the target tree, but avoid affecting the canopy cover to contribute to enhanced yew juvenile growth.</p><p class="Cos"><strong>Keywords: </strong>Biodiversity conservation; δ<sup>13</sup>C; forest management; plant-plant interaction; recruitment; <em>Taxus baccata</em>; water use efficiency.</p>
Abstract:After prospecting the vast majority of the populations and consulting herbarium collections and literature, data of distribution and demography of the Mexican populations of Taxus globosa is presented. Besides, the global distribution as the status of the species and its ecology is reviewed. Some populations are well preserved, however most of the prospected populations are under risk of anthropogenic disturbances. No real direct use of the species is performed, but other activities put pressure in their very small populations. With the data compiled, a preliminary diagnosis of its natural state is exposed towards the management and conservation of the species.
Aim of study: Taxus globosa is the only species of Taxus genus that grows in Mexico, and is a tree which is protected by the Mexican Government. This plant shares, with the European species T. baccata, the ability to produce taxanes, such as taxol. The objective of this work was to compare representative samples from two Taxus species: T. globosa Schltdl.("Mexican yew"), and T. baccata L. ("European yew"), by employing different methodological chemical and pharmacological tests.Area of study: Representative samples of Mexican yew were collected from states of Nuevo León, Querétaro, Hidalgo, and Oaxaca. The samples of European yew were taken from a clonal live collection located in the CIEF-Vaersa-Valencia (Spain). Materials and Methods:The aerial parts of all samples were extracted with methanol and subjected to TLC and HPLC analysis. Five extracts were selected for their anti-inflammatory evaluation. The extracts were tested on male ICR mice with ear inflammation induced with TPA, at a dose of 3.2 mg/ear. For T. globosa, an acute toxicity assay in female mice, according to OECD, was also conducted.Main results: Taxol was only detected in the yew trees samples collected in States of Hidalgo and Nuevo León (Mexico). In the inflammatory assay, in all treatments (except for that of MX35) induced slight, but significant, inhibition of inflammation, and only European sample M-9 showed inhibition of edema of >50%. T. globosa in the acute toxicity test causes only mild symptoms associated with a general depression of CNS, without being lethal.Research highlights: The aim of the present study was to perform a chemical analysis through quantification of taxol in the Mexican yew compared to European yew. In this research work was evaluated too for the first time the anti-inflammatory effect from both the Mexican and European yew.Keywords: Acute toxicity; anti-inflammatory activity; European yew; HPLC; Mexican yew. Citation: Osuna-Torres, L., García-Martí, X., Ventura-Zapata, E., López-Upton, J., Zamilpa-Alvarez, A., González-Cortazar, M., Herrera-Ruiz, M., Tapia-Barrera, N. (2015). Taxus
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.