Spiny Shrub Research Articles

Should I stay or should I go? Indirect effects of livestock on bird nest-site selection in arid environments

Introduced livestock may indirectly affect bird species by decreasing vegetation structure and affecting the selection of nesting sites. This is especially true for birds that use shrubs as the raw material for nest construction or for nest placement. Nesting in inadequate supporting structures or the use of inadequate raw material for nest building may increase nest vulnerability (e.g. increasing structure weakness, falling and nest exposure to predation). Accordingly, bird species show a great variation in the selectivity of nesting sites and the raw material they use. Furnariidae family members exhibit an extraordinary diversity in nest placement and structure, which allows them to survive in different arid environments. I report here on a study of nest site selection of two common furnariid species, Leptasthenura aegithaloides and Pseudoseisura gutturalis, across a grazing gradient composed by nine independent paddocks within the same arid habitat. These species use large closed-nests (>40 cm long) built with thorny branches, placed on spiny shrubs. I measured nest abundance and supporting plants characteristics, vegetation structure, browsing intensity and compared the plants selected by the birds with the surrounding vegetation. These bird species used only few plant species for nest building and location. Livestock significantly reduced vegetation cover of the species used to build and place the nests, affecting nest site selection and reducing nest abundance. As livestock density increased, both species selected aggregated plants and the tallest plants for nesting, which may increase nest exposure. Therefore, livestock may indirectly affect nest-site selection of birds ultimately affecting their nesting ecology. This work illustrates how domestic livestock, through decreasing plant cover, may affect native biota with consequences on key species within an ecosystem.

Balanites aegyptiaca (L.) Del. for dermatophytoses: Ascertaining the efficacy and mode of action through experimental and computational approaches

Abstract Dermatophytoses, also known as tinea or ringworm, are superficial infections caused by a group of fungi, the dermatophytes, affecting skin, nail, hair, and wet areas of the body. Microsporum, Trichophyton and Epidermophyton are the three genera classified as dermatophytes. Balanites aegyptiaca, the “Desert date”, is an important medicinal plant. It is a spiny shrub or short tree with sweet fruits, stone-like seeds, and oily kernels. Various parts of this plant are used in treating many diseases in humans, especially skin disease, jaundice, intestinal worm infection, wounds, malaria, epilepsy, dysentery, hemorrhoid, stomachaches, and asthma. In the present study, different parts of the plant, viz. the aerial part, fruit pulp, epicarp, and kernel portions were separated and shade dried, and extracts of these portions were prepared using the Soxhlet apparatus. The antidermatophytic activity on M.gypseum and T.rubrum was tested using the poison food technique with five different concentrations (1,2,3,4,5 mg/ml) of each extract. The in vitro results were compared with the standard drug Ketaconazole used to treat dermatophytosis. From the results of the present study, the methanol extract of the pulp portion was found to inhibit the growth of M.gypseum and T.rubrum completely from the concentration of 3 mg/ml onwards. LC-MS was performed for fruit pulp, and the identified compounds were docked with the proteins involved in ergosterol biosynthesis, protein synthesis, and the cell wall of the pathogen, and compared with the specific drugs using Glide module of Schrodinger. Cyanidin-3-O-rhamnoside, Taurocholic acid, PRZ-M382, Papaverine and Mebeverine gave better interactions and dock score than the drug, and are available in the fruit mesocarp, which is edible. This study reveals that the active compounds from the fruit pulp of Balanites aegyptiaca may have potential activity against the growth of dermatophytes, and the edible part may be validated in vivo.

Nurse plants and the regeneration niche of tree seedlings in wood-pastures from Western and North-Western Romania

Facilitation is a positive interaction demonstrated to be one of the important factors shaping the regeneration niche of trees, mostly under stressful conditions which is currently studied in the frame of complex ecological networks. The protection provided by benefactor plants for tree seedlings playing the role of beneficiaries is documented mainly in arid and semi-arid habitats or in situations where herbivores’ pressure constitutes the main stressful factor for tree regeneration. One of the iconic Transylvanian landscapes is the wood-pasture, also one of the oldest agro-forestry systems to which recent forest expansion in abandoned agricultural fields or pastures is added. The proposed work represents a preliminary investigation on the association between benefactor plants, mostly spiny shrubs (Rosa canina, Crataegus monogyna, Prunus spinosa as the most frequently encountered benefactors) and tree seedlings (Quercus spp., Tilia spp., Carpinus betulus, Fraxinus angustifolia, Pyrus pyraster as most frequently encountered beneficiaries), in four different locations from North-Western and Western Romania, wood-pastures, abandoned pastures and abandoned agricultural fields under the consideration that the main stressful factor is represented by livestock grazing. Bipartite, qualitative merged network was generated depicting the interaction between beneficiaries and benefactors. Commonly used metrics were calculated: connectivity, nestedness, modularity, betweenness centrality and centralization compared to similar facilitation networks presented in the literature. Facilitation network is characterized by high nestedness (N=0.896), lack of modularity, relatively high connectance (C=0.233), features encountered in mutualistic networks also. Betweenness centrality scores highlighted the keystone benefactor and beneficiary species, while betweenness centralization score (0.192) indicates the fact that there are several species sharing the dominant position in terms of interactions. The analysis of measurement data (seedlings’ and benefactor plants’ heights, distance from focal seedlings to nearest benefactor species and orientation) showed that there is common pattern in orientation (most of the benefactor species oriented toward South or South West) also in dimensional variability (MANOVA results).

A new species of Genista sect. Spartocarpus (Fabaceae) from Karaman (Turkey)

Genista Linnaeus (1753: 709) is a large genus of spiny and non-spiny shrubs including over 90 species, mainly distributed in the Mediterranean region but also represented throughout most of western and central Europe, and extending to the southeast of the former USSR, Turkey, Syria and North Africa. The genus is usually arranged into three subgenera and 10 sections (Gibbs 1966, 1968). Among these, Genista subg. Spartocarpus Spach (1844: 240) is widespread in the Balkan Peninsula and the eastern Mediterranean, but has a secondary centre in the Balearic Islands, Sardinia, Sicily, north Africa, and southern Spain (Pardo et al. 2004). According to the most recent generic revision (Gibbs 1966), G. subg. Spartocarpus includes four sections: sect. Spartocarpus, sect. Acanthospartum Spach (1844: 247), sect. Fasselospartum Gibbs (1966: 20) and sect. Cephalospartum Spach (1844: 254).

Variability in floral traits and reproductive success among and within populations of Berberis microphylla G. Forst., an underutilized fruit species

Abstract Berberis microphylla G. Forst. (calafate) is an evergreen and spiny shrub considered as a non-timber patagonian forest product, that is relevant for diversification of agrifood production, particularly interesting since its black–blue fruits are rich in phenolic compounds. The objective of this research is to analyze the variability in floral traits and reproductive success of Berberis microphylla G. Forst. among and within three populations of Tierra del Fuego along three growing seasons. The presence of variability in some floral traits as well as in the reproductive success of B. microphylla among and within three Tierra del Fuego populations was observed, in agreement with the environmental conditions i.e. mean daily temperatures and accumulated rainfall for the three populations and the three growing seasons. Flower dry weight and gynoecium area are good indicators of flower quality (i.e. ovule number), with positive and significant correlations between them (flower dry weight with gynoecium area, r = 0.551; p=

Antiproliferative and Apoptotic Activities of the Medicinal Plant Ziziphus obtusifolia.

Background:Ziziphus obtusifolia is a spiny shrub found in Northwest Mexico desert, with traditional medicinal use to treat several diseases including cancer.Objective:The aims of the present study were to evaluate the antiproliferative and apoptotic activities of the aerial parts of this plant.Materials and Methods:The methanol extract and its fractions were prepared using several solvents. The antiproliferative activity was evaluated by the (3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium) (MTT) assay on HeLa, A549, RAW 264.7, M12.C3.F6, and L-929 cell lines, and the apoptotic activity using Annexin V and (5,50,6,60-tetra-chloro-1,10,3,30-tetra-ethylbenzimidazol-carbocyanine iodide) staining. The most active fraction was further separated by column chromatography.Results:The most active fraction was hexane with an IC50 of 90.4 μg/mL against RAW 264.7, 94 μg/mL against M12.C3.F6, 165.5 μg/mL against HeLa and 187.7 μg/mL against A549 cell lines. In apoptotic activity assays the methanol extract and its n-hexane fraction were found to induce mitochondrial depolarization in HeLa cells (83 and 87% respectively), and both induced the externalization of the phosphatidylserine increasing the percentage of cells in early apoptosis from 1.4% in untreated control cells, to 1.9% and 3.5% for methanol extract and n-hexane fraction-treated cells, respectively, statistically different for the total percentage of apoptotic cells (P < 0.05).Conclusions:These results show that Z. obtusifolia has antiproliferative and apoptotic activities in vitro and confirms its use in traditional medicine.SUMMARYThe methanol extract and its fractions using several solvents were evaluated in the antiproliferative activity by the MTT assay on HeLa, A549, RAW 264.7, M12.C3.F6, and L-929 cell lines, and the apoptotic activity using Annexin V and (5,50,6,60-tetra-chloro-1,10,3,30-tetra-ethylbenzimidazol-carbocyanine iodide) staining. The most active fraction against cell lines was hexane. In apoptotic activity assays, the methanol extract and its n-hexane fraction were found to induce mitochondrial depolarization. This results we showed that Ziziphus obtusifolia has antiproliferative and apoptotic activities in vitro.Abbreviations Used: DMEM: Dulbecco's modified eagle's medium, DMSO: Dimethyl sulfoxide, MTT: (3-4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium), JC-1: (5,50,6,60-tetra-chloro-1,10,3,30-tetra-ethylbenzimidazol-carbocyanine iodide), FBS: Fetal bovine serum, CAPE: Caffeic acid phenethyl ester, PBS: Phosphate-buffered saline.

Facilitation by a Spiny Shrub on a Rhizomatous Clonal Herbaceous in Thicketization-Grassland in Northern China: Increased Soil Resources or Shelter from Herbivores.

The formation of fertility islands by shrubs increases soil resources heterogeneity in thicketization-grasslands. Clonal plants, especially rhizomatous or stoloniferous clonal plants, can form large clonal networks and use heterogeneously distributed resources effectively. In addition, shrubs, especially spiny shrubs, may also provide herbaceous plants with protection from herbivores, acting as ‘shelters’. The interaction between pre-dominated clonal herbaceous plants and encroaching shrubs remains unclear in thicketization-grassland under grazing pressure. We hypothesized that clonal herbaceous plants can be facilitated by encroached shrubs as a ‘shelter from herbivores’ and/or as an ‘increased soil resources’ under grazing pressure. To test this hypothesis, a total of 60 quadrats were chosen in a thicket-grassland in northern China that was previously dominated by Leymus chinensis and was encroached upon by the spiny leguminous plant Caragana intermedia. The soil and plant traits beneath and outside the shrub canopies were sampled, investigated and contrasted with an enclosure. The soil organic matter, soil total nitrogen and soil water content were significantly higher in the soil beneath the shrub canopies than in the soil outside the canopies. L. chinensis beneath the shrub canopies had significantly higher plant height, single shoot biomass, leaf length and width than outside the shrub canopies. There were no significantly differences between plant growth in enclosure and outside the shrub canopies. These results suggested that under grazing pressure in a grassland undergoing thicketization, the growth of the rhizomatous clonal herbaceous plant L. chinensis was facilitated by the spiny shrub C. intermedia as a ‘shelter from herbivores’ more than through ‘increased soil resources’. We propose that future studies should focus on the community- and ecosystem-level impacts of plant clonality.

Structural anti-herbivore defense reduction of two Patagonian spiny shrubs in response to long time exclusion of large herbivores

This work focuses on the structural defenses of the two dominant spiny shrub species of the Patagonian shrub-grass steppe. We compared the amount of structural defenses (spines and thorns) of Mulinum spinosum (Cav.) Pers. (Apiaceae) and Adesmia volckmannii Phil. (Fabaceae) between grazed and long term non-grazed plots. M. spinosum showed a higher spinescence than A. volckmannii. Moreover, both species plants located in grazed plots showed higher spinescence than those located in non-grazed ones. Therefore, we can conclude that (1) M. spinosum has higher spinescence than A. volckmannii, probably because sheep prefer M. spinosum flowers than A. volckmannii leaves; and (2) both M. spinosum and A. volckmannii showed an increase of spinescence induced by herbivory. These responses may be evidences of co-evolution between these shrub species and large wild browsers that guarantee an adequate capacity to tolerate herbivory disturbance. Such capacity would be important to maintain community functioning, because shrubs provide secure sites for seed germination and, in some cases, are able to set symbiotic interactions with N-fixing bacteria.

Identifying the genetic diversity, genetic structure and a core collection of Ziziphus jujuba Mill. var. jujuba accessions using microsatellite markers.

Ziziphus is a genus of spiny shrubs and small trees in the Rhamnaceae family. This group has a controversial taxonomy, with more than 200 species described, including Chinese jujube (Ziziphus jujuba Mill. var. jujuba) and Indian jujube (Z. mauritiana), as well as several other important cultivated fruit crops. Using 24 SSR markers distributed across the Chinese jujube genome, 962 jujube accessions from the two largest germplasm repositories were genotyped with the aim of analyzing the genetic diversity and structure and constructing a core collection that retain high genetic diversity. A molecular profile comparison revealed 622 unique genotypes, among which 123 genotypes were genetically identical to at least one other accessions. STRUCTURE analysis and multivariate analyses (Cluster and PCoA) roughly divided the accessions into three major groups, with some admixture among groups. A simulated annealing algorithm and a heuristic algorithm were chosen to construct the core collection. A final core of 150 accessions was selected, comprising 15.6% of the analyzed accessions and retaining more than 99.5% of the total alleles detected. We found no significant differences in allele frequency distributions or in genetic diversity parameters between the chosen core accessions and the 622 genetically unique accessions. This work contributes to the understanding of Chinese jujube diversification and the protection of important germplasm resources.

Goat pasturing—A biological solution to counteract shrub encroachment on abandoned dry grasslands in Central Europe?

Shrub encroachment is one of the main causes of dry grassland loss in Central Europe. Abandoned semi-natural grasslands are often overgrown by thorny or spiny shrubs. Such unpalatable shrubs have frequently established by selective foraging during periods with low grazing pressure, particularly if sheep herding was performed. Feeding behaviour and diet selection vary between different livestock species and especially browsing goats are increasingly recognized for preventing woody encroachment. However, little is known about the appropriate timing of the grazing regime and the selection of woody species on abandoned dry grasslands already dominated by thorny and spiny shrubs.We quantified the foraging behaviour of Boer goats by direct observation on three encroached paddocks in the lower Saale River valley (Central Germany), which were grazed yearly from spring to autumn with a high stocking rate (0.6–0.8 LU/ha/yr). Feeding activities, the proportion of browsed woody species and identity of the browsed species were recorded in five minute intervals during a total of 30days in spring and 30days in summer/autumn. Dry grassland vegetation and woody coverage were observed on grazed and ungrazed 25-m2 plots for seven years.Contrary to other studies on grazing animals, we found that goats frequently browsed on spiny or thorny shrub species, if these species exhibited a high share of the shrub coverage. Altogether we detected a significant relationship between the abundance of woody species and browsing time on the respective species. The goats tended to spend more time browsing in spring than in summer/autumn. As a result of the browsing activity, we observed a significant decrease of woody coverage within pastures from 69.8% to 37.4% over seven years, which was positively related to the frequency of typical and endangered dry grassland species. An opposite trend was recorded on ungrazed plots.Therefore, goat pasturing with high-stocking rates and an early start in spring can be an efficient method for improving shrub-encroached dry grasslands during the restoration phase.

Direct versus indirect facilitation (herbivore mediated) among woody plants in a semiarid Chaco forest: A spatial association approach

AbstractIn arid environments, direct facilitation (microhabitat amelioration) and indirect facilitation (‘associational resistance’ via protection from herbivory) among plants of different species may act simultaneously. Little is known about their relative effects. One way to disentangle the effects is by evaluating spatial associations. We examined the relative importance of these two mechanisms of facilitation in the semiarid Chaco vegetation of north‐central Argentina, through an eight‐way observational study in which we quantified the degree of spatial association between saplings of each of two key tree species, Schinopsis lorentzii (Anacardiaceae) and Aspidosperma quebracho‐blanco (Apocynaceae), with shrub neighbours either possessing spines or without spines and in both an ungrazed site and a site with a long history of cattle grazing. We analysed data across 400 subparcels at each site with spatial analysis by distance indices. Saplings of both tree species showed positive spatial associations with spiny shrubs in the grazed site but not in the ungrazed site, and never with non‐spiny shrubs. This result suggests that spiny shrubs may indeed provide associational resistance for saplings of key tree species in grazed habitats in these dry subtropical forests, that is, that indirect facilitation may predominate over direct facilitation. If confirmed by experimental studies, this result can have implications for the silvopastoral management of rapidly expanding ranches in the semiarid Chaco, where current practice includes the near elimination of native shrubs.

Rewilding with large herbivores: The importance of grazing refuges for sapling establishment and wood-pasture formation

Rewilding is a novel nature management type that aims at restoring natural processes with minimal human intervention. It is increasingly employed on abandoned agricultural lands in Europe, but empirical studies are scarce. Rewilding may lead to formation of wood-pastures, arguably the primeval landscape in parts of Europe before Neolithic times. We investigated sapling establishment, a key process for wood-pasture formation, in the Oostvaardersplassen: Europe’s oldest large-scale rewilding area, with high densities of free-roaming large herbivores. We transplanted saplings of pioneers, spiny shrubs, and hardwood species and studied how herbivore accessibility (grazed control, partial and full exclosure), vegetation type (tall roughs; short lawns) and soil-tillage (mimicking wild boar rooting) affected sapling survival for four years. No single sapling survived in grazed controls, while survival in exclosures was 25%. Differences in survival between partial and full exclosures were minor, indicating that reduced herbivore access is sufficient for sapling survival. Survival was higher in lawn than in rough in both exclosure types and for all species, indicating positive effects of preceding grazing. Soil tillage initially benefitted all species, but effects lasted for pioneers only, suggesting that – once introduced – wild boar rooting may affect woody species composition. We conclude that rewilding with herbivores can successfully form wood-pasture landscapes on abandoned agricultural land as long as grazing refuges are present that allow for sapling establishment. As grazing refuges are generally lacking on abandoned agricultural lands, where most rewilding is foreseen, we recommend that future projects consider the presence – or creation – of grazing refuges.

Shrub-oak seedling spatial associations change in response to the functional composition of neighbouring shrubs in coastal dune forest communities

The abundance and distribution of tree regeneration is driven by several processes acting at both the seedling establishment and survival stages. Plant– plant interactions highly contribute to regeneration dynamics through seed dispersal and competition or facilitation processes. The aim of the present study was to assess the relative importance of different functional groups of shrubs for the early establishment of oak seedlings in the coastal forest communities of south-western France. We applied spatial and non-spatial analysis methods in eleven 315-m2 regeneration plots. Within each plot, oak seedlings (height 50 cm and DBH <4 cm) were mapped to ±1 cm. The spatial distribution patterns of the oak seedlings (Quercus robur, Quercus suber and Quercus ilex) were analysed for each species while the association patterns were detected between the seedlings of the three oaks and four functional groups of shrubs (Fagaceae, Ericaceae, Fabaceae and spiny shrubs) known to have contrasting effects on other species. Oak seedling species were very often spatially aggregated at short distances (<1 m). Oak seedlings were also positively associated with shrubs of the same species within the Fagaceae group, whereas we detected negative associations with Ericaceae and no dominant significant pattern for Fabaceae and spiny shrubs. The aggregated distribution of seedlings of the three oak species was due to short-distance seed dispersal, which also explained their positive spatial associations with Fagaceae shrubs. Thus, in order to enhance oak recruitment in these ecosystems, forest managers should focus on the control of Ericaceae shrubs, while preserving Fagaceae shrubs.

&lt;p align="left"&gt;Lycium ningxiaense, a replacement name for Lycium parvifolium T.Y. Chen &amp;amp; Xu L. Jiang (Solanaceae)

The genus Lycium Linnaeus (1753: 191) is one of the largest genera in Solanaceae Jussieu (1789: 124), with approximately 92 species in the monogeneric tribe Lycieae Hunziker (1977: 28; Levin et al. 2011). It is disjunctly distributed in temperate to subtropical regions between the northern and southern hemispheres, mainly in North America, South America, southern Africa, and Eurasia (Zhang et al. 1994, Fukuda et al. 2001). It is characterized by spiny shrubs and small trees, fasciculate leaves, campanulate calyx, and by fleshy and juicy berry. Traditionally Lycium berry has been used medicinally worldwide.

Nest-site selection by the Woodchat Shrike (Lanius senator) in Boroyeh Wildlife Sanctuary, Inner Iran

We studied nest site selection by the Woodchat Shrike, Lanius senator, in a wildlife sanctuary in semi-arid central Iran. Habitat variables such as plant species, relative vegetation cover, height and number of plant species, distance to the closest water source in nest-site areas were compared with randomly selected non-used areas. The results showed that the most important factors influencing nest-site selection by this bird were vegetation cover, especially the number and height of spiny shrub species such as Atraphaxis spinosa and Amygdalus reuteri which were significantly more abundant in Woodchat Shrike breeding areas compared to control areas.

Tree regeneration under high levels of wild ungulates: The use of chemically vs. physically-defended shrubs

Wild ungulate populations have increased dramatically in the last decades, limiting tree regeneration. However, how different types of shrubs (chemically vs. physically-defended) act as seedlings facilitators under different types of ungulate damage (browsing or rooting) remains largely unknown. Here, we integrate both biotic and abiotic stress to assess seedling survival in three microsites [open, under chemically-defended (aromatic) shrubs and under physically-defended (spiny) shrubs]. We studied seedling survival of a Mediterranean oak (Quercus pyrenaica) for two contrasting levels of abiotic stress (dry vs. wet growing seasons) in environments where deer (Cervidae) and wild boar (Sus scrofa) are abundant. After the first summer 24.7% of seedlings were still alive in a wet year whereas only 9.0% seedlings survived in a dry year. Seedling survival was higher under shrub cover, independently of the annual weather conditions and the shrub type. Shrubs, on average, reduced seedling mortality by ungulates approximately 75% in a wet year and only 50% in a dry year due to the greater and earlier impact of browsers (deer) in drier years, when preferred food (green grass) is scarce. Physically-defended shrubs prevent wild boar damage better than other microsites, reducing 35–59% boar damage in comparison to other types of shrubs and 70–77% in comparison to open microsites and, therefore, serve as good nurse shrubs in environments where wild boar are abundant. Physically-defended shrubs also worked well as defense against browsers at low abiotic stress (wet years) but diminished its efficiency in comparison to chemically-defended shrubs at high abiotic stress due to the greater browsing activity of deer on spiny shrubs in dry years. Thus, we recommend the use of chemically-defended shrubs as seedling protectors against browsers. Restoration efforts (e.g. reforestation) under high level of ungulates should take into account the type of ungulate damage (browsing vs. rooting) and the predominant type of shrub mechanism against herbivores (chemical vs. physical) to use shrub cover more efficiently in future restoration practices.

Genetic characterization of Berberis species collected from Kunhar River catchment using morphological and molecular markers

The Berberis genus represents perennial spiny shrubs with reddish brown to pale yellowish stem bark. From Pakistan Berberis have been classified on morphological characters but no attempt was made to classify it on molecular traits. The first documented report of using molecular as well as numerical parameters for dissecting the genus from different localities of Kunhar River catchment. The assessment of Berberis is genus based upon 19 morphological characters. The data obtained from numerical analysis was computed for getting dendrogram, which classified 24 collections into two major groups i.e. group A and B. All the genotypes of group-A was having red fruits whereas the collections clustered into group-B produce black fruits. Molecular characterization was done with the help of 12 RAPD primes to elaborate genetic polymorphism in Berberis colletions. The primers based amplification in the collections revealed high level of genetic polymorphism, i.e. 6-86%. The genetic diversity estimated as genetic distances computed into dendrogram, separated the collections into 5 distinct groups A, B, C, D and E, disseminated as Berberis parkeriana, B. lycium, B. pachyacantha, B. kunwarensis and B. orthobotrys, respectively. However the collection B-8, which closely resembles B. parkeriana morphology was out grouped and needs future elaboration with more markers assorted discrimination.

Determination of toxic heavy metals in indigenous medicinal plants used in Rawalpindi and Islamabad cities, Pakistan

Ethnopharmacological relevanceHistory of medicinal plants used in local healthcare systems dates back centuries as the user considers them safe from toxic effects. Present study was aimed to document the commonly used indigenous medicinal plants and to investigate the metal toxicity and impact of pollution load in most frequently used medicinal plants from study area. Material and methodsSemi-structured interviews and rapid appraisal approach were employed to record the ethnomedicinal information and toxic metals were analyzed through flame atomic absorption spectrophotometer. Results and discussionA total of 21 wild medicinal plants was reported, and 7 were screened for toxic metal analysis. Oral mode of application (93%) was the chief route of herbal remedy administration, and leaves were found to be used as major plant part against different diseases. Main sources of remedies were wild herb (68%) followed by wild trees (18%), wild spiny shrubs (09%) and wild shrubs (5%). Trend of metal concentration was found as Fe>Ni>Cr>Pb>Cu>Zn>Mn>Cd. Indigenous medicinal plants of both cities posed the toxicity risk for Ni, Cu, Fe and crossed the safety limits set by WHO. ConclusionMedicinal plants of Rawalpindi were more toxic compared to the medicinal plants of Islamabad. Prolonged intake or over dose of these medicinal plants may lead to chronic accumulation of various elements that may cause severe hazardous effect upon human health.

Stomatal Abundance and Distribution in &amp;lt;i&amp;gt;Prosopis strombulifera&amp;lt;/i&amp;gt; Plants Growing under Different Iso-Osmotic Salt Treatments

Changes in several environmental parameters are thought to affect stomatal development. Under salt stress, plants can regulate their transpiration flux through a better control of the stomatal opening (as a short-term response) and through modifications of leaf anatomy (as a long-term response). We investigate how leaf micromorphology (stomatal abundance and distribution) of the halophyte Prosopis strombulifera (a spiny shrub particularly abundant in high-salinity areas of central Argentina) responds to different water status when plants are subjected to different salt treatments (NaCl, Na2SO4 and their iso-osmotic mixture). Different salt treatments on P. strombulifera plants influenced leaf micromorphological traits differently. In this study, Na2SO4-treated plants showed an increase in stomatal density (SD) and epidermal cell density (ECD) (with smaller stomata) at moderate and high salinity (-1.9 and -2.6 MPa), whereas in NaCl and NaCl + Na2SO4 treated plants, a decrease in these variables was observed. In Na2SO4-treated plants, transpiration was the highest at moderate and high salinity, with the highest content of ABA registered. A possible explanation is that, despite of these high ABA levels, there is no inhibition in stomatal opening, resulting in increased water loss, growth inhibition, and acceleration of senescence processes. We demonstrate that P. strombulifera responds to progressive salt stress by different salts changing the leaf development, particularly in Na2SO4-treated plants, leading to structural modifications in leaf size and micro-morphology of leaf cells.

Plant competition and facilitation after extreme drought episodes in Mediterranean shrubland: does damage to vegetation cover trigger replacement by juniper woodland?

AbstractQuestionWe analyse the contribution of plant–plant interactions, particularly the outcome of plant competition and plant facilitation, on vegetation dynamics as a result of extreme drought episodes. These events will likely become more frequent under climate change, can induce vegetation die‐off and alter community dynamics. We study succession in a shrubland that tends to be replaced by juniper (Juniperus phoenicea) woodland. Due to drought, shrubland die‐off may result in competition release favouring J. phoenicea juveniles, and accelerating shrubland replacement. Alternatively, deleterious abiotic stress may increase after loss of vegetation cover protection.LocationMediterranean coastal shrublands, South Spain (Doñana National Park).MethodsField estimates of plant growth, production of needle‐like leaves, water‐use efficiency (WUE; leaf δ13C) and N leaf content of J. phoenicea juveniles in relation to plant size, drought‐induced damage, cover and habit characteristics of surrounding vegetation, and drought‐induced defoliation of the surrounding vegetation.ResultsJuniperus phoenicea juveniles growing beneath a dense vegetation canopy, particularly trees and large shrubs, were less damaged during the extreme drought episode. Plant size correlated negatively with damage. Post‐drought growth was higher in juveniles partially released from the vegetation canopy, supporting the existence of a balance between competition and facilitation. Cover of pines, large shrubs and spiny shrubs favoured growth of juveniles. Needle‐like juvenile leaves were more abundant in plants covered by the surrounding vegetation or in moderately damaged plants, but less abundant in plants without damage. Higher leaf δ13C values – indicating water stress – were measured in plants more damaged by drought and in those without canopy protection, or under vegetation strongly affected by drought. Leaf N content was lower in undamaged plants and individuals covered by surrounding vegetation.ConclusionWe did not find evidence that gaps opened by drought promoted growth of the potential replacing J. phoenicea. Thus, drought‐induced enhancement of successional replacement of shrublands with woodlands was not supported; instead, our findings foresee shrubland prevalence under future climate change conditions. Plant facilitation will play a relevant role in this process. Thus, we herein extend the relevance of plant–plant interactions to extreme drought episodes related to climate change, highlighting their role as drivers of community dynamics.