How Mediterranean Deciduous Trees Cope with Long Summer Drought? The Case of Quercus pyrenaica Forests in Western Spain

AbstractHoverflies are frequently used as biodiversity indicators and are targets of ecological studies across Europe. How hoverfly diversity responds to ecological variables is essential for species and habitat conservation. The present study is a first attempt to assess the hoverfly diversity of deciduous woodlands of Pyrenean oak (Quercus pyrenaica) in La Vera (Central-Western Spain), a habitat in need of conservation and a region that is poorly known in terms of hoverflies. Hoverflies were sampled with hand net in a mature-woodland site, a young-woodland site, and two close-by grassland sites. A higher number of species and individuals was recorded in woodland sites than in grassland sites, with only two species exclusive to the grasslands and thus, suggesting that woodland sites might be acting as a hoverfly reservoir and source. The proportion of species with phytophagous and saprophagous larvae in woodland sites was higher than outside the woodlands, probably due to a higher availability of resources in woodland sites for phytophagous and saprophagous species. The mature woodland was found to have a higher number of species and individuals than the young woodland, possibly due to the presence of grassy clearings and rotting materials in the trees of the mature woodland. The highest number of species was found in the predatory guild (Syrphinae), and smaller-bodied species within this guild were found to be more frequent in grassland than in woodland sites; possible explanations for this result are discussed. Further investigation is required to confirm and expand the results and conclusions found in this initial study on the hoverfly community of the poorly studied Q. pyrenaica woodlands of Central-Western Spain.

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White clover sensitivity to UV-B radiation - biochemical relationships and interaction with drought

Proceedings of the New Zealand Grassland Association ◽

10.33584/jnzg.2003.65.2503 ◽

2003 ◽

pp. 273-277

Author(s):

R.W. Hofmann ◽

B.D. Campbell ◽

E.E. Swinny ◽

S.J. Bloor ◽

K.R. Markham ◽

...

Keyword(s):

New Zealand ◽

White Clover ◽

Ultraviolet B ◽

Summer Drought ◽

Stress Protection ◽

Trade Offs ◽

Population Comparisons ◽

Potential Benefits ◽

Quercetin Glycosides ◽

Balance Trade

During summertime in New Zealand, white clover experiences high levels of ultraviolet-B (UV-B) radiation. This frequently coincides with periods of summer drought. We investigated responses to UV-B and to the combination of UV-B and drought in various white clover populations, including New Zealand cultivars and ecotypes as well as overseas germplasm. The results were obtained under controlled environmental conditions in three independent trials. Overall, white clover growth was reduced by UV-B. The population comparisons indicated that low growth rate and adaptation to other forms of stress may be related to UV-B tolerance under well-watered conditions, but not during extended periods of drought. Flavonoid pigments that are involved in stress protection were strongly increased under UV-B and were further enhanced in the combination of UV-B and drought. The responses among these flavonoids were highly specific, with more pronounced UV-B-induced increases in quercetin glycosides, compared to their closely related kaempferol counterparts. UV-B toler ance of the less productive white clover populations was linked to the accumulation of quercetin compounds. In conclusion, these studies suggest (i) that slow-growing white clover ecotypes adapted to other stresses have higher capacity for biochemical acclimation to UV-B under well-watered conditions and (ii) that these biochemical attributes may also contribute to decreased UV-B sensitivity across white clover populations under drought. The findings alert plant breeders to potential benefits of selecting productive germplasm for high levels of specific flavonoids to balance trade-offs between plant productivity and stress tolerance. Keywords: Drought, flavonoids, genetic variation, HPLC, kaempferol, quercetin, str ess, Trifolium repens L., ultraviolet-B, white clover

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Coexistence mechanisms of evergreen and deciduous trees based on to-pographic factors in Tiantong region, Zhejiang Province, eastern China

Biodiversity Science ◽

10.3724/sp.j.1003.2012.09242 ◽

2013 ◽

Vol 20 (2) ◽

pp. 159-167

Author(s):

Xie Yubin ◽

Ma Zunping ◽

Yang Qingsong ◽

Fang Xiaofeng ◽

Zhang Zhiguo ◽

...

Keyword(s):

Eastern China ◽

Zhejiang Province ◽

Deciduous Trees ◽

Coexistence Mechanisms

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An analysis of a spontaneous ingrowth of deciduous trees in 70 year old stands of Scots pine

Silva Gandavensis ◽

10.21825/sg.v52i0.916 ◽

1987 ◽

Vol 52 ◽

Cited By ~ 1

Author(s):

N. Lust

Keyword(s):

Scots Pine ◽

Red Oak ◽

Deciduous Trees ◽

Pedunculate Oak ◽

Black Cherry ◽

Height Distribution ◽

Stem Number ◽

Pine Stands ◽

Spontaneous Regeneration ◽

Scots Pine Stands

In 70 years old homogeneous Scots pine stands, bordered by a hardwood belt, an analysis was made about the spontaneous ingrowth of natural seedlings. The analysis involved especially the following points: species and stem number, influence of the hardwood belts, diameter and height distribution, age, growth and structure. From the age of 30 years, a spontaneous regeneration of hardwoods established in Scots pine stands. There are on average 7,000 plants per ha, 80 % of which are black cherry and another fair number are red oak and pedunculate oak. The regeneration has an average age of 25 to 30 years, it is uneven aged, contains several diameter and height classes and has already partially penetrated the upper stratum. The spontaneous ingrowth allows to convert in a simple way the homogeneous coniferous stands into mixed hardwood stands.

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Design and Construction of a Tailings Dam over an Ancient Tailings Facility at La Parrilla Mine

Mine Water and the Environment ◽

10.1007/s10230-021-00756-4 ◽

2021 ◽

Author(s):

José Miguel Galera ◽

Fernando de la Fuente ◽

Juan García ◽

Manuel Calleja ◽

Vanesa Pozo

Keyword(s):

Ground Improvement ◽

Tailings Dam ◽

Main Design ◽

Total Capacity ◽

Western Spain ◽

Design And Construction

AbstractLa Parrilla is a tungsten and tin mine located in western Spain. The tailings facility has a total capacity for 3 Mm3 and will be executed in four different phases. The main constraint for the design and construction of the tailings dam is that it has been constructed over an existing one from the 1980s. The construction activities involved removal and substitution of the old tailings from the southern portion of the facility, ground improvement with gravel columns over an area of about 10,000 m2, and construction of the dyke’s dam. This article describes the main design and construction aspects, including monitoring, until the dam’s completion in June 2019.

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West Nile and Usutu virus infections in wild birds admitted to rehabilitation centres in Extremadura, western Spain, 2017–2019

Veterinary Microbiology ◽

10.1016/j.vetmic.2021.109020 ◽

2021 ◽

Vol 255 ◽

pp. 109020

Author(s):

Daniel Bravo-Barriga ◽

Pilar Aguilera-Sepúlveda ◽

Fátima Guerrero-Carvajal ◽

Francisco Llorente ◽

David Reina ◽

...

Keyword(s):

Wild Birds ◽

Virus Infections ◽

West Nile ◽

Usutu Virus ◽

Western Spain

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Regeneration dynamics in fragmented landscapes at the leading edge of distribution: Quercus suber woodlands as a study case

Plant and Soil ◽

10.1007/s11104-021-05077-7 ◽

2021 ◽

Author(s):

Jorge Luis Montero-Muñoz ◽

Carmen Ureña ◽

Diego Navarro ◽

Valentín Herrera ◽

Pilar Alonso-Rojo ◽

...

Keyword(s):

Tree Growth ◽

Quercus Suber ◽

Forest Recovery ◽

Tree Cover ◽

Distribution Area ◽

Soil Parameters ◽

Old Fields ◽

Summer Drought ◽

Regeneration Dynamics ◽

Positive Effect

Abstract Aims We studied the regeneration dynamics of woodlands and abandoned old fields in a landscape dominated by Quercus suber in its lower limits of rainfall and temperature. Two hypotheses were established: (1) regeneration of Quercus species is strongly favored by the presence of tree cover; and (2) growth of Q. suber is driven by the climatic variables that represent the lower ecological limit of its leading distribution edge. Methods We selected woodlands and old fields with and without tree remnants (n = 3 per type), and analyzed stand structure, soil parameters and tree growth. Results Succession was arrested in old fields without tree remnants. By contrast, remnant trees were accelerators of forest recovery in old fields. Tree cover played a fundamental role in Quercus recruitment throughout seed dispersal and facilitation that mitigate the effects of summer drought on seedlings. Also, tree cover improved soil parameters (e.g., organic matter) that are important factors for understanding differences in regeneration. Winter/spring precipitation exerted a positive effect on tree growth, as well as temperatures during winter/spring and September. Conclusions Regeneration dynamics are modeled by the density of tree cover in the cold and dry edge of the distribution area of Q. suber where Q. ilex is increasing in abundance. Although temperature has a positive effect on the tree growth of Q. suber, when demographic processes are considered, decreases in water availability likely play a critical role in Q. ilex recruitment. This in turn changes dominance hierarchies, especially in abandoned areas with little or no tree cover.

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