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Plants of the Tamarix L. genus (Tamaricaceae) mainly occur in arid inlands of Asia, but a few species occur in the coastal areas of China, and the Yellow River may account for this. This study was conducted to elucidate whether and how the Yellow River affects the pattern and development of the Tamarix genus, involving two critical species of Tamarix austromongolica Nakai and Tamarix chinensis Lour. With geographical distribution data, relationships of T. austromongolica with the Yellow River and the pertaining watershed were examined using the method of random permutation. The base‐diameter structures of T. austromongolica populations were investigated and compared between different riparian lands that suffer discriminative water inundation. The nearest distances from T. austromongolica locations to the Yellow River and the pertaining watershed were significantly lower than the theoretical expectations in the condition of random distribution (p <.05). In many riparian lands along the Yellow River, wild T. austromongolica populations occurred with vigorous juveniles, despite frequent human disturbances. In coastal areas near the present estuary of the river, wild T. austromongolica plants were still found. In T. austromongolica populations near the Yellow River and sea, the rates of juvenile plants were significantly higher than in other populations situated farther from the river or sea. These findings suggest that the Yellow River can facilitate the eastward dispersal of Tamarix plants that reasonably caused the evolution from T. austromongolica to T. chinensis in ancient coasts in the China east. [ABSTRACT FROM AUTHOR]

Tamarix ramosissima has an important role in stabilizing sand dunes in desert ecosystems. Understanding the water use strategies of T. ramosissima is essential to understand its adaptations on coppice dunes. We utilized the stable isotopes δ2H and δ18O in soil water, groundwater, and xylem water to identify monthly differences in water sources. Additionally. we explored rooting depth using 2H2O as an artificial tracer. In May, T. ramosissima derived 75% of its water from shallow and middle soil layers. In July, it absorbed 90% water from middle and deep soil layers. In August and September, it acquired approximately 80% of its water from deep soil layers. The labelling using 2H as an artificial tracer indicated that the root system of T. ramosissima could reach depths >500 cm in the coppice dunes. 2H absorption was observed at depths of 100, 200, 300 and 400 cm. Soil water is the dominant water source for T. ramosissima in the coppice dunes because groundwater is at depths >30 m. The flexible water‐use strategies of T. ramosissima enable it to effectively utilize different available water sources to adapt to the arid environment. These findings improve our understanding of water uptake patterns and drought adaptation strategies of T. ramosissima in the coppice dunes of desert ecosystems. [ABSTRACT FROM AUTHOR]

The dominant woody plants of active floodplains in the northern temperate zone are various species of Salix (willows) and Populus (poplars and cottonwoods) in the tribe Saliceae of the family Salicaceae. In this review, I consider the traits that enable these species to thrive in the dynamic floodplain environment and ask why they are now declining in the northern hemisphere, yet spreading rapidly in the southern hemisphere. I reach four main conclusions. First, floodplain Saliceae exhibit traits, notably huge numbers of minute, wind‐ and water‐dispersed seeds and an exceptional capacity for vegetative propagation, that uniquely fit them for life on the active floodplain. Second, there are no functional equivalents to floodplain Salix and Populus in the southern hemisphere, which accounts for their remarkable success in invading riparian ecosystems. Third, the replacement of Saliceae by other species in the northern hemisphere has been caused mainly by changes in flow through dam construction, regulation and abstraction. The species that replace Saliceae vary according to site conditions: fertile sites in humid climates become occupied by various broadleaved trees (e.g., Acer negundo, Fraxinus pennsylvanica, Ailanthus altissima); nitrogen‐fixing shrubs dominate in areas where nitrogen is limiting but phosphorus is adequate (Amorpha fruticosa, Robinia pseudoacacia, Elaeagnus angustifolia); sites in more arid regions are occupied by various Tamarix spp. The different ecological groups of woody species are associated with contrasting changes to the floodplain ecosystem. [ABSTRACT FROM AUTHOR]

The breeding system and pollination ecology of Tamarix taklamakanensis, an endangered shrub occurring in sand dunes in the Taklamakan Desert, were examined by seven pollination treatments and observational studies in natural populations in 2019. The results showed that T. taklamakanensis exhibits an outcrossed breeding system that is dominated by insect‐pollination. It is largely self‐incompatible, with infrequent occurrence of anemophily, but relies strictly on pollinators in outcrossing. The pollen vitality could last about six days versus the stigma receptivity last about one day. Two effective pollinators were detected, and the peaks of visitation were 10:30–13:30, 16:30–17:30 and 18:30–19:30 h. Seed set by artificial cross‐pollination was significantly higher than natural pollination rates, and seed set for a population with high insect visitation rates was significantly higher than a population with low visitation rate, suggesting that pollen limitation is an important constraint on seed production for this species. Adverse weather conditions and habitat fragmentation were speculated to be the primary factors affecting the insect visitation of T. taklamakanensis in the Taklimakan Desert. [ABSTRACT FROM AUTHOR]

Understanding the effects of windbreaks on aeolian sediment transport rates, and the size distribution of aeolian sediments transported through them, is important for designing windbreaks to optimize their wind erosion mitigation benefits. This field study determines the size distribution of aeolian sediments upwind (x = −100 m), within (x = 100 and 256 m) and downwind (x = 448 and 560 m) (where x is the distance from the first row of windbreak) of a multi‐row Tamarix windbreak as the basis for further investigation of the influence of vegetation on aeolian sediment characteristics. The volumetric percentage of grains around the peaks of 100 and 20–30 µm showed variability with distance and between the three measured events. We found that the vertical distribution of grain size parameters indicated that mean grain size (Mz) may decrease with height upwind of the windbreak, and inflections were observed in the profiles of sorting (σ1), skewness (SK), and kurtosis (KG) within the windbreak, which may be attributable to blocking and trapping effect of the vegetation. Sediments were poorly sorted with the distributions of grain sizes being fine‐skewed and leptokurtic. The horizontal distribution of grain size indicated that Mz increased from x = −100 m to x = 100 m and then decreased at x = 256 m, indicating that the windbreak was unable to retain small particles. The windbreak could trap particle sizes <50 µm and particles >50 µm transported to downwind region of windbreak. Within the windbreak, SK and KG increased, and σ1 decreased. Downwind of the windbreak (at x = 448 and 560 m), Mz and KG increased, and σ1 and SK decreased. The results of the current study provide preliminary information on the variability of aeolian sediment grain sizes during transport relative to vegetation and suggest that multirow windbreaks could influence downwind particulate matter size concentrations and soil health. Core Ideas: Mean aeolian grain size decreased with height upwind of the windbreak.Sediments were poorly sorted with fine‐skewed and leptokurtic grain size distributions.Mean grain size increased within the windbreak.Skewness and kurtosis increased within the windbreak.Standard deviation in grain size decreased within the windbreak. [ABSTRACT FROM AUTHOR]

Predicting how increasing temperatures interact with other global change drivers to influence the structure and dynamics of Earth's ecosystems is a primary challenge in ecology. Our study made use of multiple simultaneous "natural experiments" to examine how rapid warming, declining nutrients, invasive consumers, and riparian invasive species management interact to influence leaf decomposition in a large and regulated river. Specifically, we compared the breakdown of cottonwood (Populus fremontii), willow (Salix exigua), and saltcedar (Tamarix sp.) leaf litter in 2022 to a previous experiment from 1998 that occurred under much cooler water temperatures, and had higher water phosphorus concentrations, low numbers of invasive New Zealand mudsnails (Potamopyrgus antipodarum), and unaltered litter chemistry from the herbivory of saltcedar leaf beetles (Diorhabda carinulata). We found that the effects of up to 10°C warmer temperatures on leaf decomposition were mediated by the establishment and management of invasive species and declining water nutrient concentrations arising from upstream reservoir lowering. Such interactions led to accelerated breakdown of saltcedar, but relatively minor effects of warming on the rate of cottonwood and willow decomposition. Additionally, our results demonstrate the potential for favorable invasive species management outcomes in the terrestrial environment to produce unintended responses in adjacent freshwater ecosystems. As temperatures continue to rise, it is critical that future studies consider how warming interacts with multiple stressors and environmental factors to influence processes such as decomposition in freshwater ecosystems. [ABSTRACT FROM AUTHOR]

With the intensification of global warming, uncertainty regarding ecosystem evolution trends in drylands has increased. The objective of this article was to test whether the desertification process of tamarisk shrubland was intensified by comparing fertile island effects and soil ecological stoichiometry characteristics at different time periods. The tamarisk shrubland in the "shrubland" and "shrub duneland" stages in the northern Tarim Basin was selected, and soil samples were collected from the tamarisk nabkhas and from the interspaces between tamarisk nebkhas at the 0‐ to 30‐cm soil layers in 2009 and 2018. Soil carbon (C), nitrogen (N), and phosphorous (P) were analyzed, and the C/N, C/P, and N/P ratios were calculated. In comparison with 2009, fertile island effects were completely collapsed in the shrub duneland stage, with no obvious changes in the shrubland stage in 2018. The average soil C/N ratio decreased from a value greater than 25 in both stages. The average value of soil C/P ratio was below 200 in the shrubland and shrub duneland stages, with almost no marked change after nine years. The soil N/P ratio in our study significantly increased in 2018 than in 2009, but the soil N/P ratio was still much less than 11.9. Significantly positive correlations were observed between the relative interaction index (RII) of soil organic carbon (SOC) and soil total nitrogen (TN) and the soil C/P and N/P ratios in the tamarisk nebkhas. These results suggested that (1) fertile island effects were positive in relation to soil stoichiometry in tamarisk nebkhas in most cases; (2) the desertification process was accelerated in the shrub duneland stage, with no obvious progress during the shrubland stage; and (3) the loss of soil C from the collapsed fertile islands could therefore accelerate global warming. [ABSTRACT FROM AUTHOR]

Background: Antimony (Sb) is considered a priority pollutant and its removal from the environment is of great importance. Among the various treatments, phytoremediation is considered an efficient method when the accumulation of this metalloid in plant tissues is sufficiently high. This work focused on removal of Sb(III) from aqueous solution at two Sb concentrations (5 and 10 ppm) and using salt as stressor (100 mmol L−1) only at the lowest Sb concentration (5 ppm). The response of two salt‐tolerant plant species – Tamarix smyrnensis and Nerium oleander – was monitored when subjected to Sb‐contaminated hydroponic solutions. Results: Plant growth and water content remained unaltered within the 15‐day experimental period, while the chlorophyll content declined significantly at the higher Sb level (10 ppm) only for N. oleander. The antioxidant enzymatic activity in T. smyrnensis with respect to guaiacol peroxidase (GPOD) and catalase (CAT) was significantly increased in the treatment under Sb and salt stress. In N. oleander there was a strong increase in GPOD activity by the exposure to Sb, whereas the CAT activity was increased considerably with the presence of salinity. Sb concentration was detected on the surface of the leaves, indicating that excretion occurred in both plants. Increased accumulation was observed in N. oleander in the absence of salinity whereas, under salt stress, Sb accumulation was considerably higher (60%) in T. smyrnensis. Notably, both plants could accumulate a high amount of Sb, preferentially in the roots, with the concentrations in the leaves being significantly lower. Conclusion: The experimental results from this study demonstrate that both plants are suitable for phytoremediation due to substantial Sb accumulation without visible Sb toxicity. © 2023 The Authors. Journal of Chemical Technology and Biotechnology published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry (SCI). [ABSTRACT FROM AUTHOR]

Efforts to conserve the pond network in the Doñana National Park are being threatened by groundwater overexploitation. The dramatic expansion of farming and tourism in nearby areas has caused a severe lowering of the water table, reducing pond hydroperiod length or even instigating pond desiccation. It is important to document the link between groundwater abstraction and pond deterioration with a view to decreasing human pressures on the park and preserving the pond network's singular biodiversity.Here, the gradual deterioration of one of the network's main ponds is described in detail by characterizing vegetation patterns within the pond's basin using orthophotos taken between 1956 and 2019.In the earliest images, the pond contained a wide central area of bare soil during its dry phase. This area was surrounded by reeds and had a line of Tamarix canariensis trees along its southern edge. Starting in 2000, the orthophotos showed the pond's gradual colonization by terrestrial vegetation. In tandem, pond hydroperiod decreased, as did the length of time the pond retained certain depths of water. In recent years, Tamarix trees finally fully invaded the pond's central area, which is surrounded by reeds and has scattered terrestrial bushes and pines.This invasion resulted from the pond's sparse inundation over recent decades, being the cover of trees related to the depth of groundwater, and is a clear sign of pond deterioration. More broadly, colonization by terrestrial vegetation has been observed in approximately 60% of the network's ponds.Colonization of temporary pond basins by terrestrial vegetation can be used as an indicator of deterioration and highlights the need for active restoration and management. [ABSTRACT FROM AUTHOR]

Biological soil crusts (biocrusts) are important components of dryland ecosystems. Vegetation strongly affects the distribution of biocrusts by influencing the soil stability, moisture and light availability. The Loess Plateau has been subjected to large‐scale restoration efforts; however, the type, coverage, and biomass of biocrusts responses to different types of vegetation restoration remain uncertain. Here, we investigated the biocrust characteristics (type, coverage, thickness, biomass, dominant cryptogam species, and relative abundance of major cyanobacteria and algae) in areas restored with different types of vegetation (Caragana korshinskii, Platycladus orientalis, Armeniaca sibirica, Populus hopeiensis, Pinus tabuliformis, Tamarix chinensis) and in a natural grassland on the Loess Plateau. Our results showed that the coverage, thickness, and biomass of the biocrusts were higher in the natural grassland than in the afforested areas, which suggests that the natural grassland is more suitable than the afforested areas for biocrust distribution. The biocrusts were composed mainly of mosses in the Pi. tabuliformis area and of cyanobacteria and algae in most of the other vegetation restoration areas. However, no biocrusts were observed in the T. chinensis area, probably because the dense canopy prevented light from reaching the soil. In addition, soil properties influenced by vegetation restoration may also affect the characteristics of biocrusts. Overall, our study suggests that natural grassland recovery, rather than afforestation, is likely the most suitable method for the development of biocrusts and provides suggestions for restoration and reconstruction on the Loess Plateau. [ABSTRACT FROM AUTHOR]

Major challenges for plant conservation are predicting the effect of habitat loss on pollination success and plant reproduction potential. Most studies report that pollinator movement is affected by quantitative and spatial characteristics of landscapes. However, little is known about the role of pollinator movement, impacted by floral volatiles and intraspecies interaction, on plant reproduction in fragmented landscapes.To clarify the effect of pollinator movement on plant reproduction relative to habitat loss, we developed an integrated model incorporating pollinator's foraging response with its dispersal process mediated by a density‐dependent dispersal (DDD) strategy. This model performed better in capturing behaviour response of pollinators than do current methods. The integrated model was verified with field results of pollinator visitation and plant reproduction of saltcedar Tamarix chinensis inhabiting the Yellow River Delta, and then was compared against a dispersal strategy called density‐independent dispersal (DID). The model was applied to landscapes with various non‐habitat percentage (NHP) to explore the effect of habitat loss on plant reproduction.Results suggested that saltcedar populations differ in their responses to habitat loss, which depended on the spatial scales considered. At landscape scale, increasing NHP significantly inhibited dispersion extent of floral volatiles and therefore reduced pollinator visitation and subsequent seed production, especially when NHP exceeded the critical threshold of 0.6. However, at patch scale, comparing with DID strategy, the DDD strategy enabled pollinators to increase their utilization of flowers by 43.42% and 6.79% in low‐density and distant plant patches, whereas their utilization was reduced by 7.75% and 2.24% in high‐density and central patches, respectively. Plant reproduction was improved correspondingly in low‐density and distant patches under different NHPs.Consequently, habitat loss inhibits the volatile dispersion and interferes the foraging success of pollinators, a major factor influencing plant reproduction at landscape scale. At patch scale, adaptive utilization of pollinators exhibiting DDD strategy alleviates the negative effect of habitat loss on plant production, and maintain plant population persistence. Since pollinator behavioural response is critical to plant reproduction, we recommend the use of the here presented integrated model to assess the impact of habitat loss on plant reproduction. Read the free Plain Language Summary for this article on the Journal blog. [ABSTRACT FROM AUTHOR]

Although I FEBS Open Bio i does not seek to judge the importance of submissions, our reviewers carefully scrutinize the experimental design and results of all papers and challenge authors about their conclusions. The editors of I FEBS Open Bio i would like to thank all those who have given their time and expertise to review articles submitted for publication in Volume 12. [Extracted from the article]

Predicting species geographic distributions is key to managing invasive species, conserving biodiversity, and understanding species' environmental requirements. Species distribution models (SDMs) commonly focus on climatic predictors, but other environmental factors can also be essential, particularly for species with specialized habitats defined by hydrologic, topographic, or edaphic conditions (e.g., riparian, wetland, alpine, coastal, serpentine). Here, we demonstrate a novel approach for capturing strong effects of both hydrologic and climatic predictors in SDMs for riparian plants, by merging analyses targeted at environmental drivers within riparian ecosystems and across the western USA (3.8 × 106 km2). We developed presence‐background SDMs from five algorithms for three invasive riparian trees (Tamarix ramossisima/chinensis [saltcedar], Elaeagnus angustifolia [Russian olive], and Ulmus pumila [Siberian elm]) and three native Populus spp. (cottonwoods). We used separate background datasets to develop models with different spatial scales of inference: (1) spatially filtered random points to represent available habitat across the study area and (2) target‐group points from Salix (willow) occurrences to represent available riparian habitat. Random‐background models captured hydrologic drivers of riparian tree distributions relative to the largely upland western USA, whereas Salix‐background models captured climatic drivers within the context of riparian ecosystems. Combining predictions from the two backgrounds identified hydrologically suitable habitats within climatically suitable regions, resulting in fewer false "absences" than either background alone, improving predictions over previous SDMs, and providing more complete information to guide management decisions. Surprisingly, the predicted habitat for U. pumila, a newly recognized riparian invader, was as or more extensive than Populus deltoides/fremontii, T. ramossisima/chinensis, and E. angustifolia, the most common riparian tree complexes in the western USA. Watersheds constituting 20% of U. pumila predicted habitat contained no occurrence records, indicating high risk of future and unrecognized invasions. Combining models from random and ecosystem‐specific target‐group backgrounds may improve SDMs for species from many specialized habitats, providing a method to link predicted distributions to localized geographic features while capturing broad‐scale climatic requirements. [ABSTRACT FROM AUTHOR]

DNA barcoding allows the identification of an organism by comparing the sequence of selected DNA regions (barcodes) with a previously compiled database, and it can be useful for taxonomic identification of species in complex genera, such as Tamarix. Many species of this genus show convergent morphology, which leads to frequent errors in their identification. Highly variable genetic markers, such as microsatellites or short sequence repeats (SSR), could be used to differentiate species where DNA barcodes fail. Here, we tested the ability of both, 5 different marker regions (rbcL, matK, ITS, trnH‐psbA, and ycf1), and 14 microsatellites, to properly identify Tamarix species, especially those from the Mediterranean Basin, and compared the pros and cons of the different analytical methods for species identification. DNA barcoding allows the genetic identification of certain species in Tamarix. The two‐locus barcodes matK + ITS and ITS + ycf1 were the best‐performing combinations, allowing up to 69% and 70%, respectively, correct identification. However, DNA barcoding failed in phylogenetically close groups, such as many Mediterranean species. The use of SSR can aid the identification of species, and the combination of both types of data (DNA barcoding and SSR) improved the success. The combination of data was especially relevant in detecting the presence of hybridization processes, which are common in the genus. However, caution must be exercised when choosing the clustering methods for the SSR data since different methods can lead to very different results. [ABSTRACT FROM AUTHOR]

The effects of river regulation on the flow patterns of rivers in western North America often mimic the impacts of naturally occurring episodic drought. On the Dolores River in southwestern Colorado, two distinct periods of flow modification have occurred, with very different drought‐like consequences for downstream habitat. The first period of major irrigation diversions (1889–1984) led to extreme low flows during the summer months with little change to spring peak flows. The second period after dam construction (1984 to present) caused a decline in peak flows but an increase in summer minimum flows. We studied the role of these different flow regimes in promoting the recruitment of non‐native tamarisk, since understanding historic patterns of recruitment may inform current and future flow management. We used dendrochronology to determine tamarisk establishment dates and tested the connection between establishment years and a suite of hydroclimatic variables. Tamarisk recruitment occurred between 1952 and 2002, with 92% of trees establishing during the first flow diversion period. The strongest hydroclimate predictor was low minimum flow for a given year, especially when coupled with higher peak flows in the year of, or before, establishment. Almost no tamarisk recruitment has occurred in the second, dam‐controlled period, where lowered peak flows and elevated minimum flows prevail. In spite of the drought tolerance of tamarisk, drought‐like conditions below this dam did not promote its invasion. Instead, the combination of lowered peaks but increased summer baseflows post‐dam has driven channel narrowing and vegetation encroachment by native willows. What current and future meteorologic drought conditions, coupled with dam‐controlled flows, will bring to the channel and adjacent riparian vegetation is uncertain, but this work may help to forecast the impacts of future river flows on riparian vegetation community evolution. [ABSTRACT FROM AUTHOR]

With the global rise of human‐mediated translocations and invasions, it is critical to understand the genomic consequences of hybridization and mechanisms of range expansion. Conventional wisdom is that high genetic drift and loss of genetic diversity due to repeated founder effects will constrain introduced species. However, reduced genetic variation can be countered by behavioral aspects and admixture with other distinct populations. As planned invasions, classical biological control (biocontrol) agents present important opportunities to understand the mechanisms of establishment and spread in a novel environment. The ability of biocontrol agents to spread and adapt, and their effects on local ecosystems, depends on genomic variation and the consequences of admixture in novel environments. Here, we use a biocontrol system to examine the genome‐wide outcomes of introduction, spread, and hybridization in four cryptic species of a biocontrol agent, the tamarisk beetle (Diorhabda carinata, D. carinulata, D. elongata, and D. sublineata), introduced from six localities across Eurasia to control the invasive shrub tamarisk (Tamarix spp.) in western North America. We assembled a de novo draft reference genome and applied RADseq to over 500 individuals across laboratory cultures, the native ranges, and the introduced range. Despite evidence of a substantial genetic bottleneck among D. carinulata in N. America, populations continue to establish and spread, possibly due to aggregation behavior. We found that D. carinata, D. elongata, and D. sublineata hybridize in the field to varying extents, with D. carinata × D. sublineata hybrids being the most abundant. Genetic diversity was greater at sites with hybrids, highlighting potential for increased ability to adapt and expand. Our results demonstrate the complex patterns of genomic variation that can result from introduction of multiple ecotypes or species for biocontrol, and the importance of understanding them to predict and manage the effects of biocontrol agents in novel ecosystems. [ABSTRACT FROM AUTHOR]

1. The form and function of terrestrial plants is largely governed by the availability of water, with plants in water-limited environments expressing traits minimizing water loss and tissue damage during drought. Areas with high salinity are analogous to those with low water availability, even where water is abundant. We evaluated variation in salinity tolerance and water use strategies in an introduced halophytic shrub, Tamarix spp by measuring gas exchange rates, biomass accumulation and turgor loss points. We hypothesized that salinity tolerance is not uniformly expressed, with high salinity ecotypes expressing more conservative water use traits that maximize hydraulic safety over high conductance rates. 2. We studied two populations of Tamarix spp. along the lower Colorado River, where groundwater salinity differed by nearly sixfold. Cuttings collected from the sites were grown in a greenhouse with five salinity levels from 0 to 32 parts per thousand (ppt), imposing increasing water limitation. 3. In situ measurements of leaf water potentials (Ψ) and branch xylem anatomy were taken on ecotypes sourced from high- and low-salinity sites. In the greenhouse, biomass and gas exchange rates were evaluated over the 0-32 ppt salinity gradient, and a separate dry down experiment was performed to determine turgor loss points and stomatal responses to drying soils. 4. In the greenhouse, the low salinity population accumulated 72% more biomass when grown at 4 ppt compared to 16 ppt, while the high salinity population produced 50% more biomass when grown at 16 ppt. Net carbon assimilation was greater at lower salinities in the low salinity population but independent of salinity in the high salinity population. The high salinity population had a lower turgor loss point and exhibited greater stomatal control relative to the low salinity population. 5. Synthesis. Results provide evidence for divergence of traits related to plant water use across salinity gradients in this recently introduced halophyte. Local adaptation to increased salinity has implications in aridland riparian ecosystems, where water management or drought may lead to altered soil salinities. The interaction of trait variation within Tamarix spp. and increasing salinity is likely to favour its continued dominance. [ABSTRACT FROM AUTHOR]

Non‐structural carbohydrate (NSC) storage may be under strong selection in woody plant species that occur across broad environmental gradients. We therefore investigated carbon (C) allocation strategies in a widespread non‐native woody plant, Tamarix. We predicted that genotypes with exposure to episodic freeze events would show elevated NSC concentrations compared to warm‐adapted genotypes with the trade‐off of reduced growth and reproduction relative to warm‐adapted populations.We established an experimental common garden using genotypes of Tamarix, sourced across a strong thermal gradient within the introduced range. We measured seasonal NSC storage in coarse roots and stems, above‐ground growth and flower production.Autumn NSC concentrations were 50% higher in genotypes from sites with episodic spring freeze events compared to genotypes from warmer sites. These cold‐adapted genotypes also had a 2.3‐fold higher starch to soluble sugar ratio than warm‐adapted genotypes. Across all genotypes and seasons, NSC storage was inversely correlated with growth and reproduction.Results suggest that Tamarix from colder locations cope with freeze events by maintaining large storage pools to support tissue regrowth, but with the trade‐off of overall reduced growth and reproduction. Our results are consistent with rapid selection in C allocation strategies in response to climate in introduced woody species. A free Plain Language Summary can be found within the Supporting Information of this article. [ABSTRACT FROM AUTHOR]

Premise: Plants rely on pools of internal nonstructural carbohydrates (NSCs: soluble sugars plus starch) to support metabolism, growth, and regrowth of tissues damaged from disturbance such as foliage herbivory. However, impacts of foliage herbivory on the quantity and composition of NSC pools in long‐lived woody plants are currently unclear. We implemented a controlled defoliation experiment on mature Tamarix spp.—a dominant riparian woody shrub/tree that has evolved with intense herbivory pressure—to test two interrelated hypotheses: (1) Repeated defoliation disproportionately impacts aboveground versus belowground NSC storage. (2) Defoliation disproportionately impacts starch versus soluble sugar storage. Methods: Hypotheses were tested by transplanting six Tamarix seedlings into each of eight cylinder mesocosms (2 m diameter, 1 m in depth). After 2.5 years, plants in four of the eight mesocosms were mechanically defoliated repeatedly over a single growing season, and all plants were harvested in the following spring. Results: Defoliation had no impact on either above‐ or belowground soluble sugar pools. However, starch in defoliated plants dropped to 55% and 26% in stems and roots, respectively, relative to control plants, resulting in an over 2‐fold higher soluble sugar to starch ratio in defoliated plants. Conclusions: The results suggest that defoliation occurring over a single growing season does not impact immediate plant functions such as osmoregulation, but depleted starch could limit future fitness, particularly where defoliation occurs over multiple years. These results improve our understanding of how woody plants cope with episodic defoliation caused by foliage herbivory and other disturbances. [ABSTRACT FROM AUTHOR]

Groundwater is increasingly becoming a permanent and steady water source for the growth and reproduction of desert plant species due to the frequent channel cutoff events in arid inland river basins. Although it is widely acknowledged that the accessibility of groundwater has a significant impact on plant species maintaining their ecological function, little is known about the water use strategies of desert plant species to the groundwater availability in Daryaboyi Oasis, Central Tarim Basin. This study initially determined the desirable and stressing groundwater depths based on ecological and morphological parameters including UAV-based fractional vegetation cover (FVC) images and plant growth status. Then, leaf δ13C values of small- and bigsized plants were analyzed to reveal the water use strategies of two dominant woody species (Populus euphratica and Tamarix ramosissima) in response to the groundwater depth gradient. The changes in FVC and growth status of plants suggested that the actual groundwater depth should be kept at an appropriate range of about 2.1-4.3 m, and the minimum groundwater depth should be less than 7 m. This will ensure the protection of riparian woody plants at a normal growth state and guarantee the coexistence of both plant types. Under a desirable groundwater condition, water alternation (i.e., flooding and rising groundwater depth) was the main factor influencing the variation of plant water use efficiency. The obtained results indicated that bigsized plants are more salt-tolerant than small ones, and T. ramosissima has strong salt palatability than P. euphratica. With increasing groundwater depth, P. euphratica continuously decreases its growth status to maintain hydraulic efficiency in drought condition, while T. ramosissima mainly increases its water use efficiency first and decreases its growth status after then. Besides, in a drought condition, T. ramosissima has strong adaptability than P. euphratica. This study will be informative for ecological restoration and sustainable management of Daryaboyi Oasis and provides reference materials for future research programs. [ABSTRACT FROM AUTHOR]

Coal-mined areas are often associated with hostile environmental conditions where the scarcity of water and key nutrient resources negatively affect plant growth and development. In this study we specifically addressed how different combinations of water (W), nitrogen (N) and phosphorus (P) might affect morpho-physiological and biochemical attributes of a native shrub species, Tamarix chinensis, grown on coal mine spoils. Our results show that under greenhouse conditions the application of moderate-to-high doses of W, N and P considerably improved growth-associated parameters (i.e. plant height, stemdiameter, dryweight), aswell as gas-exchange parameters, photosynthetic pigment contents and leafwater status of T. chinensis. Under field conditions high W and low N, P doses led to significant increases in plant growth-associated traits, gas-exchange parameters and leaf water status. Plant growth was generally higher under greenhouse conditions mainly because seedlings facedmultiple stress when growing under field conditions. Low W-regime, regardless of N-P additions, improved osmotic adjustments in leaf tissues and also boosted the activity of several antioxidant enzymes to reduce the oxidative stress associated with W scarcity under greenhouse conditions. Importantly, our study shows how maximum growth performance of T. chinensis under field conditions was achieved at W, N and P doses of 150 mm year-1, 80 kg ha-1 and 40 kg ha-1, respectively. Our findings suggest that achieving optimal rates of W, N and P application is crucial for promoting the ecological restoration of coal-mined areas with T. chinensis under arid environmental conditions. [ABSTRACT FROM AUTHOR]

Here, we studied the evolution of salt glands in 11 species of Tamarix and determined their role in adaptation to saline environments by measuring the effect of NaCl on plant growth and salt gland characteristics. Cluster analysis divided Tamarix species into three types (types I–III) according to salt‐gland characteristics. A phylogenetic tree based on ITS sequences indicated an evolutionary relationship consistent with the geographical distribution of Tamarix. We measured growth under different NaCl conditions (0, 100, 200, and 300 mM) for 40 days in three species (T. gallica, T. ramosissima, and T. laxa) representing the three Tamarix types. With increasing NaCl concentration, the biomass of all species was significantly reduced, especially that of T. gallica. Salt secretion ability and salt‐gland density showed similar trends in three types. The order of salt tolerance was type I > type II > type III. We conclude that during Tamarix adaptation to salinity, salt‐gland evolution followed two directions: one increasing salt‐gland density, and the other increasing salt secretion rate per salt‐gland. This study provides a basis for potential mechanisms of recretohalophyte adaptation to salinity. [ABSTRACT FROM AUTHOR]

Biological control of Tamarix spp. (tamarisk) with Diorhabda spp. (tamarisk beetle) was initiated in several states in the Western United States in 2001. We analysed 12 years of evapotranspiration (ET), net ecosystem production (NEP), and beetle abundance data from a tamarisk‐invaded site in Western Nevada along the Truckee River. Diorhabda carinulata (northern tamarisk beetle) appeared at the site in 2007. Large beetle outbreaks and associated defoliation of the tamarisk occurred in 2008 and 2009, then the beetle population was highly variable from year to year. Since 2016, the beetle population declined. Growing season ET noticeably declined from direct beetle herbivory in 2008, 2009, and 2010, but the decline in ET was seasonally transient as trees regrew leaves. In 2012 and 2013, total growing season ET was low, likely due to the combined effects of drought and beetle herbivory pressure. Total seasonal ET losses and NEP were primarily driven by annual precipitation with higher values in wetter years and reduced values when precipitation fell below 100 mm. In the last 2 years of the study, 2017–2018, there were few to no beetles observed at the site, and we measured increased tamarisk leaf area index, ET, and NEP. Since 2010 at the study site, no further releases of the beetles have occurred due to wildlife concerns, and subsequent declines in beetle populations where such that the "outbreak" conditions apparently required to impair tamarisk physiological function and significantly reduce ET have not occurred. ET and photosynthesis were highly correlated (r2 ≥.91) to the Landsat‐satellite normalized difference vegetation index (NDVI). Using a relationship between growing season ET and NDVI, we estimated ET for five additional tamarisk sites along several southwestern U.S. rivers. In the 2005 to 2018 analysis period, NDVI‐estimated ET declined at all sites after beetle arrival with three sites showing a recovery in pre‐beetle ET rates in subsequent years. At the other three sites, ET rates have not recovered to pre‐beetle levels. [ABSTRACT FROM AUTHOR]

Lead and arsenic are regarded as the significant heavy metal ions which have a great contribution in the pollution of industrial wastewaters. In this research, the adsorption of Pb (II) and As (III) ions from the aqueous solution was studied using activated carbon prepared from Tamarix leaves as a new adsorbent. The adsorbent was characterized by Brunauer, Emmett, and Teller (BET), X‐ray fluorescence spectrometer (XRF), scanning electron microscope (SEM), energy dispersive X‐ray and mapping (EDX/Map), X‐ray diffraction (XRD), and Raman techniques. Batch experiments were designed to investigate the significance of adsorption parameters including pH, adsorbent dosage, time, temperature, and initial concentration on Pb and As ions removal efficiencies. The experiments indicated that the highest adsorption efficiencies were 97.86% for lead and 96.18% for arsenic ions in pH values of 6 for Pb and 7 for As, adsorbent dosage of 3 g/L and initial concentration of 10 mg/L for both of them, and contact time of 60 min and 40 min for Pb and As ions, respectively. Additionally, the results of adsorption kinetics showed that the pseudo second‐order model was more effective for the description of adsorption mechanism of both metals compared to the pseudo first‐order model. The equilibrium behavior of arsenic and lead ions were described well by Langmuir and Freundlich models, respectively. In addition, thermodynamic studies showed that the current adsorption processes were exothermic and spontaneous. Based on the results, the prepared adsorbent can be considered as a good adsorbent for the removal of Pb and As ions from aqueous solutions. [ABSTRACT FROM AUTHOR]

The science‐practice gap is often cited as a limitation to successful restoration outcomes; however, the existence of such a gap in information exchange is rarely measured. Here, we quantify the gap by focusing on common recommendations from both scientists (i.e. researchers) and managers (i.e. practitioners, land managers) on what is needed for successful restoration. We surveyed 45 managers associated with 244 invasive species (Tamarix spp.) removal projects across the southwestern U.S. to determine the degree to which they have utilized four strategies advocated by scientists: (1) collaborate widely, (2) monitor beyond cursory visual methods, (3) use a variety of information sources, and (4) consider project goals beyond invasive species removal. Half of these managers were also interviewed to assess managers' perceptions of the role of science in restoration. Twenty‐three scientists specializing in Tamarix‐related research in this region were also surveyed to assess how much they understood and/or shared the concerns of land managers. We found that managers were following scientists' recommendations and that managers' perceptions of the role of science in land management did not have any bearing on the management actions taken. Scientists reported being influenced by managers, and the concerns of scientists and managers were more overlapping than expected. Boundary organizations and river‐wide partnerships were often cited as important in facilitating effective communication between land managers and scientists. A lack of funding for monitoring and for longer‐term projects was cited by both groups as a limitation to incorporating scientists' recommendations into restoration. [ABSTRACT FROM AUTHOR]

Tamarix is one of the taxonomically most complex genera among the angiosperms, and there is little consensus regarding its infrageneric classification. Here we present the most complete phylogenetic reconstruction of the genus to date. This includes a DNA phylogenetic tree based on nuclear ribosomal ITS, and a plastid DNA phylogeny based on three intergenic spacers (trnS‐trnG, ndhF‐rpl32, and trnQ‐rps16). In total, both nuclear and plastid phylogenetic analyses include more than 70 samples of 39 species from 27 countries, which represent close to 60% of the diversity of the genus. Two complementary trees, based only on one plastid marker, are also included. The first, based on trnS‐trnG, is used to increase the number of species related to T. amplexicaulis. The second, based on ndhF‐rpl32, is used to investigate the separation between T. tetrandra and T. parviflora. The incongruence between the available infrageneric classifications and the molecular results is confirmed. A reticulate evolution is inferred from the trees, showing characters such as vaginate leaves appearing at different stages along the evolutionary history of the genus. The presence of T. canariensis outside the Canary Islands is cast into doubt, and all such records from NW Africa and Europe are here considered to belong to T. gallica. The results also suggest independence of T. karelinii from T. hispida, and T. parviflora from T. tetrandra. Relationships between a number of species are still not resolved, and additional studies will be needed to further refine the complex taxonomy of Tamarix. [ABSTRACT FROM AUTHOR]

Summary: The exotic Tamarix chinensis and T. ramosissima, believed to have been introduced into South Africa in the early 1900s to control erosion on mine dumps, are invading riparian zones and have been proven to hybridise with T. usneoides, which is native to southern Africa. In this study, we document the abundance of invasive Tamarix genotypes in South Africa. Eleven riparian zones from the Northern, Eastern and Western Cape Provinces were surveyed. Three quadrats of 600 m2 each were selected per site. Plant density, canopy cover and tree height were recorded to quantify invasiveness. Leaf samples were randomly collected from an average of eight individuals per site to record genotypes of the invaders. Tamarix density and canopy cover were significantly greater than those of co‐occurring trees and shrubs in Olifants River in De Rust (Western Cape Province). A linear correlation between percentage Tamarix spp. cover and other co‐occurring tree and shrub species showed a strong negative relationship (R2 = 0.78). Genetic analysis showed that the Western and Eastern Cape Provinces have the highest proportion of the exotic Tamarix species and their hybrids. This suggests that these two provinces require urgent management intervention to contain the spread of the weed. The distinctions made between the native and the exotic Tamarix species and their hybrids should also facilitate the testing and future release of potential biological control agents. [ABSTRACT FROM AUTHOR]

The taxonomy and phylogenetic relationships of related taxa are important for understanding the biology of a species. Also, spatial distribution of genetic variation may offer insights into history of range shifts and demographic changes. The genus Tamarix L. from the Old World is a taxonomically challenging group that has widely expanded its range in the recent past. We examined genomic diversity patterns and the taxonomic identities of Korean Tamarix species whose taxonomy has remained unresolved. We used a total of 1773 SNP data from genotyping by sequencing for 37 Tamarix plants representing two species; T. chinensis and T. ramosissima to infer species delimitation and the geographic distribution of genomic diversity. Clustering (STRUCTURE; PCA, neighbor joining) and phylogenetic tree results indicated that the two morphologically similar species T. chinensis and T. ramosissima are genetically distinct and the two Korean populations (Sihwa & Songdo) are clustered closely with T. chinensis. Approximate Bayesian Computation based hypothesis testing results suggested that one of the two Korean populations, Songdo might have primarily been derived from the native area, China, followed by range expansion to Sihwa with a secondary admixture event between an established population, Songdo, and a native population, Beijing. [ABSTRACT FROM AUTHOR]

Environmental flow releases are an effective tool to meet multiple management objectives, including maintaining river conveyance, restoring naturally functioning riparian plant communities, and controlling invasive species. In this context, predicting plant mortality during floods remains a key area of uncertainty for both river managers and ecologists, particularly with respect to how flood hydraulics and sediment dynamics interact with the plants' own traits to influence their vulnerability to scour and burial.To understand these processes better, we conducted flume experiments to quantify different plant species' vulnerability to flooding across a range of plant sizes, patch densities, and sediment condition (equilibrium transport versus sediment deficit), using sand‐bed rivers in the U.S. southwest as our reference system. We ran 10 experimental floods in a 0.6 m wide flume using live seedlings of cottonwood and tamarisk, which have contrasting morphologies.Sediment supply, plant morphology, and patch composition all had significant impacts on plant vulnerability during floods. Floods under sediment deficit conditions, which typically occur downstream of dams, resulted in bed degradation and a 35% greater risk of plant loss compared to equilibrium sediment conditions. Plants in sparse patches dislodged five times more frequently than in dense patches. Tamarisk plants and patches had greater frontal area, larger basal diameter, longer roots, and lower crown position compared to cottonwood across all seedling heights. These traits were associated with a 75% reduction in tamarisk seedlings' vulnerability to scour compared to cottonwood.Synthesis and applications. Tamarisk's greater survivability helps to explain its vigorous establishment and persistence on regulated rivers where flood magnitudes have been reduced. Furthermore, its documented influence on hydraulics, sediment deposition, and scour patterns in flumes is amplified at larger scales in strongly altered river channels where it has broadly invaded. Efforts to remove riparian vegetation using flow releases to maintain open floodways and/or control the spread of non‐native species will need to consider the target plants' size, density, and species‐specific traits, in addition to the balance of sediment transport capacity and supply in the river system. [ABSTRACT FROM AUTHOR]

Climate change and competition from invasive species remain two important challenges in restoration. We examined the hypothesis that non‐native tamarisk (Tamarix spp.) reestablishment after aboveground removal is affected by genetics‐based architecture of native Fremont cottonwood (Populus fremontii) used in restoration. As cottonwood architecture (height, canopy width, number of stems, and trunk diameter) is, in part, determined by genetics, we predicted that trees from different provenances would exhibit different architecture, and mean annual maximum temperature transfer distance from the provenances would interact with the architecture to affect tamarisk. In a common garden in Chevelon, AZ, U.S.A. (elevation 1,496 m), with cottonwoods from provenances spanning its elevation distribution, we measured the performance of both cottonwoods and tamarisk. Several key findings emerged. On average, cottonwoods from higher elevations were (1) two times taller and wider, covered approximately 3.5 times more basal area, and were less shrubby in appearance, by exhibiting four times fewer number of stems than cottonwoods from lower elevations; (2) had 50% fewer tamarisk growing underneath, which were two times shorter and covered 6.5 times less basal area than tamarisk growing underneath cottonwoods of smaller stature; and (3) the number of cottonwood stems did not affect tamarisk growth, possibly because the negative relationship between cottonwood stems and basal area. In combination, these findings argue that cottonwood architecture is affected by local conditions that interact with genetics‐based architecture. These interactions can negatively affect the growth of reinvading tamarisk and enhance restoration success. Our study emphasizes the importance of incorporating genetic and environmental interactions of plants used in restoration. [ABSTRACT FROM AUTHOR]

Northern tamarisk beetles (Diorhabda carinulata) were released in the Upper Colorado River Basin in the United States in 2004–2007 to defoliate introduced tamarisk shrubs (Tamarix spp.) in the region's riparian zones. The primary purpose was to control the invasive shrub and reduce evapotranspiration (ET) by tamarisk in an attempt to increase stream flows. We evaluated beetle–tamarisk interactions with MODIS and Landsat imagery on 13 river systems, with vegetation indices used as indicators of the extent of defoliation and ET. Beetles are widespread and exhibit a pattern of colonize–defoliate–emigrate, so that riparian zones contain a mosaic of completely defoliated, partially defoliated, and refoliated tamarisk stands. Based on satellite data and ET algorithms, mean ET before beetle release (2000–2006) was 416 mm/year compared to postrelease (2007–2015) ET of 355 mm/year (p < 0.05) for a net reduction of 61 mm/year. This is lower than initial literature projections that ET would be reduced by 300–460 mm/year. Reasons for the lower‐than‐expected ET reductions are because baseline ET rates are lower than initially projected, and percentage ET reduction is low because tamarisk stands tend to regrow new leaves after defoliation and other plants help maintain canopy cover. Overall reductions in tamarisk green foliage during the study are 21%. However, ET in the Upper Basin has shown a steady decline since 2007 and equilibrium has not yet been reached. Defoliation is now proceeding from the Upper Basin into the Lower Basin at a rate of 40 km/year, much faster than initially projected. [ABSTRACT FROM AUTHOR]

Invasion of riparian habitats by non-native plants is a global problem that requires an understanding of community-level responses by native plants and animals. In the Great Plains, resource managers have initiated efforts to control the eastward incursion of Tamarix as a non-native bottomland plant ( Tamarix ramosissima) along the Cimarron River in southwestern Kansas, United States. To understand how native avifauna interact with non-native plants, we studied the effects of Tamarix removal on riparian bird communities. We compared avian site occupancy of three foraging guilds, abundance of four nesting guilds, and assessed community dynamics with dynamic, multiseason occupancy models across three replicated treatments. Community parameters were estimated for Tamarix-dominated sites (untreated), Tamarix-removal sites (treated), and reference sites with native cottonwood sites ( Populus deltoides). Estimates of initial occupancy ( ψ2006) for the ground-to-shrub foraging guild tended to be highest at Tamarix-dominated sites, while initial occupancy of the upper-canopy foraging and mid-canopy foraging guilds were highest in the treated and reference sites, respectively. Estimates of relative abundance for four nesting guilds indicated that the reference habitat supported the highest relative abundance of birds overall, although the untreated habitat had higher abundance of shrub-nesters than treated or reference habitats. Riparian sites where invasive Tamarix is dominant in the Great Plains can provide nesting habitat for some native bird species, with avian abundance and diversity that are comparable to remnant riparian sites with native vegetation. Moreover, presence of some native vegetation in Tamarix-dominated and Tamarix-removal sites may increase abundance of riparian birds such as cavity-nesters. Overall, our study demonstrates that Tamarix may substitute for native flora in providing nesting habitat for riparian birds at the eastern edge of its North American range. [ABSTRACT FROM AUTHOR]

Most studies assessing vegetation response following control of invasive Tamarix trees along southwestern U.S. rivers have been small in scale (e.g., river reach), or at a regional scale but with poor spatial-temporal replication, and most have not included testing the effects of a now widely used biological control. We monitored plant composition following Tamarix control along hydrologic, soil, and climatic gradients in 244 treated and 172 reference sites across six U.S. states. This represents the largest comprehensive assessment to date on the vegetation response to the four most common Tamarix control treatments. Biocontrol by a defoliating beetle (treatment 1) reduced the abundance of Tamarix less than active removal by mechanically using hand and chain-saws (2), heavy machinery (3) or burning (4). Tamarix abundance also decreased with lower temperatures, higher precipitation, and follow-up treatments for Tamarix resprouting. Native cover generally increased over time in active Tamarix removal sites, however, the increases observed were small and was not consistently increased by active revegetation. Overall, native cover was correlated to permanent stream flow, lower grazing pressure, lower soil salinity and temperatures, and higher precipitation. Species diversity also increased where Tamarix was removed. However, Tamarix treatments, especially those generating the highest disturbance (burning and heavy machinery), also often promoted secondary invasions of exotic forbs. The abundance of hydrophytic species was much lower in treated than in reference sites, suggesting that management of southwestern U.S. rivers has focused too much on weed control, overlooking restoration of fluvial processes that provide habitat for hydrophytic and floodplain vegetation. These results can help inform future management of Tamarix-infested rivers to restore hydrogeomorphic processes, increase native biodiversity and reduce abundance of noxious species. [ABSTRACT FROM AUTHOR]

Questions To what extent may impact vary according to the invaded community, region or sites? Do impact thresholds exist, above which native species richness and/or cover declines rapidly? Does impact following invasion by the exotic shrub Baccharis halimifolia differ from that of a native shrub ( Tamarix gallica) during natural successions? Location Mediterranean coast, SE France. Methods Vegetation was sampled on 120 4-m² quadrats, half of which were in areas invaded by B. halimifolia and the other half in nearby non-invaded areas, in two distinct community types nested in three sites in each of two regions. Mixed models were built to explain variations in impacts on native vegetation according to community types, sites and regions. Next, 85 additional plots variously invaded by B. halimifolia were used to assess the nature of the relationships between B. halimifolia cover and impact in Juncus communities. Linear regressions were compared to polynomial regressions, and when relevant, regression trees were built to identify threshold values. Finally, we compared the vegetation from 90 plots either dominated by B. halimifolia, by T. gallica (a native shrub) or without a shrub layer (control) using dissimilarity indices in wet meadows. Results The magnitude of B. halimifolia impacts depended mainly on community type, with no differences between regions. Community structure (species richness, Shannon's diversity) declined linearly with increasing cover of B. halimifolia, with the most rapid decline in annual species. Native species cover fitted better with a cubic regression, with an impact threshold of around 86% cover of B. halimifolia. Impact of B. halimifolia on community diversity was higher than that of the native shrub T. gallica. While the magnitude of species composition changes was comparable for both shrubs, the higher nestedness component of dissimilarity found for B. halimifolia may indicate a higher short-term impact. Conclusion Improved understanding of the impacts of exotic shrubs on community structure and composition can be gained via comparisons with the impacts caused by native shrubs. Higher impacts of the exotic B. halimifolia on Mediterranean salt marsh vegetation are likely explained by a denser canopy, shorter juvenile period and more frequent recruitment. [ABSTRACT FROM AUTHOR]

Afforestation of shelterbelts is a sustainable practice to protect highways from shifting sand dunes in desert areas. The Taklimakan Desert Highway Shelterbelt ( TDHS) in China is known as 'the Great Green Wall of Taklimakan Desert' and borders a 436-km distance along the highway. This study assessed the early survival, above-ground growth, and root growth of three salt- and drought-tolerant plant species ( Calligonum aborescens Litv. , Tamarix ramosissima Ledeb. , and Haloxylon ammodendron (C. A. Mey.) Bunge) in TDHS; those were drip-irrigated with local high saline groundwater. The results demonstrated that more than 80% of Haloxylon ammodendron seedlings could survive regardless of irrigation water salinities ranging from 2.82 to 29.70 g/L. In contrast, survival rates of Calligonum aborescens seedlings were greater than 65% when using irrigation water salinities ≤13.99 g/L and less than 50% when irrigated with water having salinities of 20.99-29.70 g/L, respectively. However, plant survival rates of Tamarix ramosissima were much lower than 50% when irrigated with water having salinities >4.82 g/L. Furthermore, under the same salinity, the height, crown width, and maximum width of basal stems were the greatest for Calligonum aborescens plants and the lowest for Tamarix ramosissima plants. Root length varied among the species depending on tree age and the applied water characteristics. We conclude that afforestation is feasible with saline water in this extreme arid shifting desert, particularly Calligonum aborescens plants should be grown at the outer margin of the shelterbelt due to its faster growth to more quickly stabilize the shifting sand. Our study may provide a good resolution for afforestation and marginal saline water utility in most arid and semiarid regions. [ABSTRACT FROM AUTHOR]

Tamarisk ( Tamarix spp.) is an invasive shrubby tree native to Eurasia. Since its introduction to the United States, it has established itself along Southwestern American riparian systems. Control programs aimed at removing tamarisk were initiated in an effort to restore riparian areas, and potentially salvage water. Biological control of tamarisk with the Diorhabda spp. (leaf beetles) defoliates tamarisk and reduces evapotranspiration (ET). In 2009, the beetle arrived at Mesquite, Nevada, along the Virgin River, and dispersed to the Lower Virgin River riparian area in 2011. This study estimates reduced Lower Virgin River riparian ET caused by leaf beetle activity. Multi-temporal spectral angle mapper was used to detect established leaf beetle communities in the Lower Virgin River riparian area. The Mapping Evapotranspiration at High Resolution with Internal Calibration (METRIC) land surface energy balance model was used to estimate Lower Virgin River riparian ET. METRIC ET results were compared with eddy covariance ET estimates made in tamarisk along the Lower Virgin River. Comparisons indicated that METRIC accurately estimates pre-beetle ET and post-beetle reduced ET. The 2007-2010 (pre-beetle) average ET for the Lower Virgin River riparian area was 1245 mm/yr compared with 1041 mm/yr for the 2011-2012 (post-beetle) period. Given the 4700 acre riparian area, leaf beetle induced defoliation results in a mean annual ET reduction of 3161 acre-ft. In 2011 and 2012, volumetric reductions to ET were estimated to be 817 and 5505 acre-ft, respectively. The METRIC model was shown to be a useful tool for monitoring ET during pre-beetle and post-beetle defoliation periods. Copyright © 2015 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Diorhabda carinulata (northern tamarisk beetle) has been released in the western United States as a biological control agent for the invasive plant Tamarix spp. (tamarisk). A few studies have been conducted analysing the effects of beetle defoliation on tamarisk water consumption, but predefoliation and post-defoliation comparison based on field data is scarce. The question of whether beetles substantially alter tamarisk water consumption is still open for discussion. In this study, an eddy covariance station and groundwater monitoring well were installed in a tamarisk stand along the Virgin River near Mesquite, NV, in 2010 to observe the impacts of tamarisk defoliation on evapotranspiration (ET) and groundwater levels. ET was calculated using the eddy covariance method and the White method and supported by Landsat remote sensing estimates. Data collected in 2010 established a baseline since the beetles arrived at the site in late 2010 and started feeding on foliage causing tamarisk trees to turn to brown during 2011. Repeated defoliations in 2011 and 2012 show that post-defoliation ET values and magnitude of diurnal groundwater-level fluctuations decreased compared with the predefoliation values. Estimated annual ET and annual average daily groundwater fluctuations were reduced by 18% and 35%, respectively. However, the magnitude of effects of defoliation was dependent on the growth stage of tamarisk at the time of defoliation. Also, ET recovered within a month as tamarisk established new leaves. Results from this study suggest that long-term changes in ET are highly dependent on repeated defoliation occurrences over several years. [ABSTRACT FROM AUTHOR]

Ethylene responsive factors (ERFs) are plant-specific transcription factors that are involved in a variety of biological processes. We previously demonstrated that an ERF gene from Tamarix hispida, ThERF1, encodes a protein binding to GCC-box and DRE motifs and negatively modulates abiotic stress tolerance. In the present study, microarray analysis was performed to study the genes regulated by ThERF1 on a genomic scale. There were 154 and 307 genes (respectively representing 134 and 260 unique genes) significantly up- and downregulated by ThERF1 under salt stress conditions, respectively. A novel motif, named TTG, was identified to be recognized by ThERF1, which commonly presents in the promoters of ThERF1-targeted genes. The TTG motif is also bound by other ERFs of a different subfamily from T. hispida and Arabidopsis, indicating that it is commonly recognized by ERF proteins. The binding affinities of ERFs to the TTG motif are significantly induced by salt stress. The TTG motif is more enriched than the GCC-box and DRE motifs in the promoters of ThERF1-targeted genes. Taken together, these studies suggested that the TTG motif plays an important role in the gene expression regulated by ERFs in response to salt stress. [ABSTRACT FROM AUTHOR]

The earlier typifications of 12 names of Tamarix ( T. arabica, T. aralensis, T. boveana, T. chinensis, T. hohenackeri, T. karelinii, T. kotschyi, T. leptopetala, T. laxa var. araratica, T. laxa var. subspicata, T. mannifera var. persica and T. pycnocarpa) are discussed. In eight cases, a second-step lectotype was selected, because several specimens of the type collection were found at the herbaria where the first-step lectotypes were indicated. Five previous indications of holotypes were corrected to lectotype designations, as no particular specimens had been explicitly mentioned in the protologue. The typifications of T. hampeana and T. mascatensis are clarified. Moreover, four additional names ( T. bengalensis, T. gallica var. arborea, T. mannifera var. purpurascens and T. passerinoides var. macrocarpa) are lectotypified, and an epitype is selected for T. pallasii var. macrostemon. Lectotypes are designated from the material present at G-BOIS, P, P-LOUR, PRC, and W. Most of the 19 names treated in this work were described in the 18th and 19th centuries by important European botanists such as Bunge (12), Boissier (1), Candolle (1), Ehrenberg (3) and Loureiro (1). [ABSTRACT FROM AUTHOR]

Invasive species may be viewed as 'passengers' that spread in response to environmental changes rather than 'drivers' of ecological impacts. To date, however, there has been no examination of how these alternative models affect public risk perception, sense of responsibility, and willingness to take action. We report on an experimental study of how these models affected respondents' ( N = 456) willingness to take action to address two invasive species: tamarisk and garlic mustard. We found that the traditional driver model, compared to the passenger model, increased perception of risk to humans and the environment, both of which contributed to willingness to take action. The driver model, however, also decreased personal causal responsibility, though only when human responsibility for introduction was not mentioned. Our findings suggest that these alternative models create trade-offs for communication that necessitate contextual framing that attends to audience sense of risk and responsibility. [ABSTRACT FROM AUTHOR]

Ethylene-responsive factor ( ERF) family is one of the largest families of plant-specific transcription factor that can positively or negatively regulate abiotic stress tolerance. However, their functions in regulating abiotic stress tolerance are still not fully understood. In this study, we characterized the functions of an ERF gene from Tamarix hispida, ThERF1, which can negatively regulate abiotic stress tolerance. The expression of ThERF1 was induced by salinity, PEG-simulated drought and abscisic acid (ABA) treatments. ThERF1 can specifically bind to GCC-box and DRE motifs. Overexpression of ThERF1 in transgenic Arabidopsis plants showed inhibited seed germination, and decreased fresh weight gain and root growth compared with wild-type (WT) plants. In addition, the transcript levels of several superoxide dismutase (SOD) and peroxidase (POD) genes in transgenic plants were significantly inhibited compared with in WT plants, resulting in decreased SOD and POD activities in transgenic plants under salt and drought stress conditions. Furthermore, the reactive oxygen species (ROS) levels, malondialdehyde (MDA) contents and cell membrane damage in ThERF1-transformed plants were all highly increased relative to WT plants. Our results suggest that ThERF1 negatively regulates abiotic stress tolerance by strongly inhibiting the expression of SOD and POD genes, leading to decreased ROS-scavenging ability. [ABSTRACT FROM AUTHOR]

ABSTRACT Understanding mechanisms of exotic species' invasions is essential to managing riparian landscapes throughout the world. In the southwestern USA, the two most dominant invaders of riparian habitats are the exotic tree species tamarisk ( Tamarix ramosissima, Tamarix chinensis, and their hybrids) and Russian olive ( Elaeagnus angustifolia). These plants were introduced around 1900, and their success may be facilitated by river regulation, river channel changes, and precipitation patterns. We hypothesized that riparian invasion in Canyon de Chelly, Arizona, was initiated by a change point event such as plantings, dam construction, or channel incision and that establishment near a change point was tied to flood events. We aged tamarisk, Russian olive, and native cottonwood trees from study sites in Canyon de Chelly and used tree ring analysis to determine the year of establishment and the elevation of the germination point relative to the channel. We used Bayesian Poisson regression and information theoretics to identify change points and precipitation variables driving annual tree establishment. We found that most tamarisk and Russian olive trees established in the late 1980s, and most cottonwoods established in 1930-1950 and 1980-2000. Regression models indicated that change points occurred in 1983 for Russian olive and 1988 for tamarisk, and precipitation was important for establishment. Although plantings and river regulation probably played a role in tree invasion, our results suggest that these species required precipitation and stream channel change for widespread establishment in Canyon de Chelly. The factors driving riparian invasions may not be those often associated with degraded rivers, such as altered hydrographs and land management changes, thus requiring analyses of the full range of ecological and physical processes. Copyright © 2012 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Bioenergy development can offer beneficial ecological and economic synergies through the expansion of eco-logical restoration projects. Such synergies are demonstrated by means of a case study conducted in central Washington State, where a 52.4-ha ecological restoration site on the Yakama Reservation generated 34 mega-grams (Mg) of invasive tree biomass per hectare, costing $988 ha"1. A geospatial model of transportation costs estimated that extracted invasive tree biomass can generate revenues throughout 1103 803 ha when delivered to a proposed bioenergy facility in White Swan, Washington, providing 53 000-180000 Mg of biomass per year for several decades. Thermochemical analyses revealed that the elevated nitrogen, sulfur, and ash con-tent in two prolific invasive trees - Russian olive (Elaeagnus angustifolia) and salt cedar (Tamarix spp) - will limit demand for either of these invasive species. We compare our regional data to national estimates, and show the broader potential for expanding ecological restoration activities and biomass supplies through the revenues generated by the sale of invasive tree wood-waste into bioenergy markets. [ABSTRACT FROM AUTHOR]

Question Do soils impacted by Tamarix spp. affect the growth of plants used for restoration through altered soil chemistry and/or plant-soil feedbacks? Location The Bighorn River, the Yellowstone River and the Fort Peck Reservoir, Montana, western USA. Methods Soil was collected from paired subsites where Tamarix was either present or absent along three water bodies. To evaluate chemical and biological soil effects on plant growth, eight plant species ( Achnatherum hymenoides, Astragalus cicer, Dalea candida, Elymus lanceolatus, Leymus cinereus, Pascopyrum smithii, Ratibida columnifera and Trifolium pratense) commonly used in restoration projects at Tamarix-invaded sites were grown in the collected soil. Plant-soil feedbacks were evaluated by growing two species ( D. candida and P. smithii) in greenhouse soils inoculated with small amounts of the field soils. Germination, emergence and growth characteristics were compared between Tamarix-invaded and un-invaded subsites and across water bodies. Results Seedling emergence and plant relative growth rate, total biomass production and allocation of resources to roots and shoots were not negatively affected in field soils or in greenhouse soil inoculated with soil from areas where Tamarix was present. In fact, overall, plants emerged earlier and produced more biomass in soils affected by Tamarix than in soils from where Tamarix was not present. These results indicate that for sites in the northern range of Tamarix, restoration would not be inhibited by Tamarix-induced soil changes. Conclusions Tamarix is a relatively new invader in the northern USA, and little is known about its impacts in this area or the potential implications for restoration. However, our results indicate that neither altered soil chemistry nor plant-soil feedbacks negatively impact native plant growth, and restoration efforts would not be hindered by Tamarix-induced changes to soil chemistry or microbiota. [ABSTRACT FROM AUTHOR]

Tamarix leaf beetles ( Diorhabda carinulata) have been widely released on western United States rivers to control introduced shrubs in the genus Tamarix, with the goals of saving water through removal of an assumed high water-use plant, and of improving habitat value by removing a competitor of native riparian trees. We review recent studies addressing three questions: (1) to what extent are Tamarix weakened or killed by recurrent cycles of defoliation; (2) can significant water salvage be expected from defoliation; and (3) what are the effects of defoliation on riparian ecology, particularly on avian habit? Defoliation has been patchy at many sites, and shrubs at some sites recover each year even after multiple years of defoliation. Tamarix evapotranspiration ( ET) is much lower than originally assumed in estimates of potential water savings, and are the same or lower than possible replacement plants. There is concern that the endangered southwestern willow flycatcher ( Empidonax trailli extimus) will be negatively affected by defoliation because the birds build nests early in the season when Tamarix is still green, but are still on their nests during the period of summer defoliation. Affected river systems will require continued monitoring and development of adaptive management practices to maintain or enhance riparian habitat values. Multiplatform remote sensing methods are playing an essential role in monitoring defoliation and rates of ET on affected river systems. [ABSTRACT FROM AUTHOR]

In Mediterranean coastal areas, changes in precipitation patterns and seawater levels are leading to increased frequency of flooding and to salinization of estuaries and freshwater systems. Tamarix spp. are often the only woody species growing in such environments. These species are known for their tolerance to moderate salinity; however, contrasting information exists regarding their tolerance to flooding, and the combination of the two stresses has never been studied in Tamarix spp. Here, we analyse the photosynthetic responses of T. africana Poiret to temporary flooding (45 days) with fresh or saline water (200 m m) in two Italian provenances (Simeto and Baratz). The measurements were conducted before and after the onset of flooding, to test the possible cumulative effects of the treatments and effects on twig aging, and to analyse the responses of twigs formed during the experimental period. Full tolerance was evident in T. africana with respect to flooding with fresh water, which did not affect photosynthetic performances in either provenance. Saline flooding was differently tolerated by the two provenances. Moreover, salinity tolerance differently affected the two twig generations. In particular, a reduction in net assimilation rate (−48.8%) was only observed in Baratz twigs formed during the experimental period, compared to pre-existing twigs. This reduction was a consequence of non-stomatal limitations (maximum carboxylation rate and electron transport), probably as a result of higher Na transport to the twigs, coupled with reduced Na storage in the roots. [ABSTRACT FROM AUTHOR]

In the Mediterranean basin, Tamarix spp. constitute important populations along rivers and sea coasts, and might be primarily subjected to water level fluctuations and salinization, as a consequence of global climate change. Here, we analyze leaf gas exchange and xylem anatomy during a water level decrease below the soil surface after short-term flooding with fresh- and saline-water (200 mM) in order to predict Tamarix africana Poiret responses under future environmental conditions. Fresh-water level reduction negatively affected stomatal conductance (−56.3 %), but only when water decreased to the lowest level (15 cm below the soil surface). No effects on assimilation rates and xylem vessel dimensions occurred. Under saline conditions, the rate of the water level decrease was lower compared to the non-saline treatment, as stomatal conductance was negatively affected by salinity (−59.5 %) and significantly declined over time. Moreover, decreases in mean xylem vessel area (−51.3 %), assimilation rates (−52.2 %) and stomatal conductance (−76.0 %) were also observed compared to the control, indicating both an osmotic stress and a toxic effect of NaCl on leaf gas exchange. These leaf responses were probably induced by greater belowground-root salt absorption and transport compared to previous flooding conditions, as confirmed by the increase in salt excretion (+473.2 %). The results emphasize the survival risk of Tamarix spp. to water level variation under both saline and non-saline conditions, and the need of management practices focused on the conservation of these populations. [ABSTRACT FROM AUTHOR]

Fertile islands are created and maintained by a combination of physical and biologically mediated processes. Plants have been shown to be very important in the formation of fertile islands, and recent research indicates that the activities of burrowing animals have a significant influence on the physiochemical properties of soil that can promote the development of fertile islands. In this paper, we chose tamarisk ( Tamarix spp.)-a constructive species that grows in the oasis-desert ecotone, and the great gerbil ( Rhombomys opimus)-a widely distributed rodent in Central Asia to study the influence of great gerbils on soil nutrient dynamics in tamarisk mounds. Results indicate that fertile islands exist in tamarisk mounds without burrows of the great gerbil. However, the great gerbil's burrowing activities promote the fertile island effect in tamarisk mounds: soil nutrients under shrubs with great gerbil activity were significantly higher than inter-mound areas in both surface soil and deep soil from 15 to 50 cm. Available nitrogen in mounds with rodent burrows was over twice as high as in tamarisk mounds without burrows at the same depth. The great gerbil's burrowing activities promote the concentration of soil nutrients in the tamarisk mounds. [ABSTRACT FROM AUTHOR]

In classical weed biological control, small collections of arthropods are made from one or a few sites in the native range of the target plant and are introduced to suppress the plant where it has become invasive, often across a wide geographic range. Ecological mismatches in the new range are likely, and success using the biocontrol agent may depend on postrelease evolution of beneficial life history traits. In this study, we measure the evolution of critical day length for diapause induction (day length at which 50% of the population enters dormancy), in a beetle (Diorhabda carinulata) introduced into North America from China to control an exotic shrub, Tamarix spp. Beetle populations were sampled from four sites in North America 7 years after introduction, and critical day length was shown to have declined, forming a cline over a latitudinal gradient At one field site, decreased critical day length was correlated with 16 additional days of reproductive activity, resulting in a closer match between beetle life history and the phenology of Tamarix. These findings indicate an enhanced efficacy and an increasingly wider range for D. carinulata in Tamarix control. [ABSTRACT FROM AUTHOR]

Nonnative Tamarix spp. (saltcedar) is among the most invasive and common trees along riparian habitats in the western U S, impacting native plant communities and habitat quality. Tamarix dominance causes a reduction in habitat physiognomic heterogeneity in riparian habitats. Animal abundance, diversity and habitat associations in monotypic stands of saltcedar remain largely unexplored for non-avian communities. We sampled small vertebrate and ground arthropod communities in monotypic Tamarix stands and in mixed stands of Tamarix and native ( Populus, Salix, and Prosopis spp.) trees in riparian habitats along the Virgin River in the Mojave Desert. Our survey of faunal communities suggests that many species of arthropods, reptiles and small mammals utilize both Tamarix-dominated and mixed habitats along the Virgin River. Small mammal and lizard communities were dominated by generalist species. Mixed stands had greater arthropod abundance, lizard abundance and small mammal diversity; whereas, monotypic and mixed stands had similar lizard diversity. The habitat of mixed sites was characterized by 'nativeness' (areas with native riparian trees) and less 'shady exotic thickets' (areas with Tamarix and high overstory cover) compared to Tamarix-dominated stands. There were species-specific responses to habitat physiognomy. Peromyscus maniculatus (deer mouse) was associated with shady exotic thickets. Sceloporus magister (desert spiny lizard) and Neotoma lepida (desert woodrat) were associated with native trees and woody debris. Seven rodent and lizard species' abundances were explained by habitat physiognomy variables. Rare and specialist species were more impacted by nonnative vegetation. These results contribute to the body of research on animal utilization of nonnative habitats and relation to habitat physiognomy. Management of nonnative plants should consider how control activities could impact habitat physiognomy and native animal communities in riparian habitat. [ABSTRACT FROM AUTHOR]