Tamarix Spp Research Articles

Salt Cedar Intake by Cattle, Sheep, and Goats Following 21 Days of Exposure

Salt cedar (Tamarix spp. L), is found across Texas and the western United States, primarily near riparian areas. Introduced in the 1800s as an ornamental plant, salt cedar escaped domestic gardens, invading native rangelands. Mechanical and chemical control options for salt cedar are available, but effective control can be difficult and cost prohibitive. Sheep and goats will readily consume salt cedar after exposure at weaning, and goats readily consume the plant when released on rangelands. Unfortunately, sheep and goats are not a viable option in many areas due to predation or lack of appropriate fencing. The objectives of this study were to determine if cattle would consume salt cedar at a similar level (body weight basis) as sheep and goats and to determine if preconditioning improved acceptance of salt cedar by cattle. Angus-Hereford cross heifers (n = 15), Rambouillet lambs (n = 15), and Boer-Spanish cross kids (n = 15) were placed in individual pens for 21 d and fed salt cedar leaves and tender stems daily. For the first 21 d, eight head from each species were fed a basal diet and salt cedar while 7 head only received the basal diet. The amount of salt cedar in the diet was increased from 5% of the diet to 10% of the diet after 7 d of feeding and fed until d 21. From d 22 to 28 both naïve and familiar animals were fed salt cedar daily. All animals readily increased intake of salt cedar. By d 7, cattle, sheep, and goats consumed the plant, but intake varied daily for cattle and sheep. After the first 7 d, goats consistently ate more (P < 0.05) salt cedar than cattle or sheep. While goats may consume more salt cedar, cattle may be a viable option to reduce salt cedar cover when goats are not a viable option.

Variation in salinity tolerance and water use strategies in an introduced woody halophyte (Tamarix spp.)

Abstract 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. 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. 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. 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. 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.

The Charming Threat Against the Groundwater Resources: Tamarix Trees Utilized for Landscaping

Datça peninsula has a limited water budget due to its geographical structure. Although many studies have been carried out to protect water resources, no study has been conducted on some specific plant species' excessive water consumption for the Datça region. The study identifies and evaluates the negative impacts of Tamarix spp (Tamaracaceae) across the coastal landscapes of Datça. As an invasive alien species, initially used as a short-term solution to flooding and increasing soil nutrients, Tamarix spp has more adversities than the anticipations held during its introduction. Tamarix plant has compromised several ecosystems hence rendering it an extremely repulsive plant that requires termination. The study utilized literature to garner relevant information regarding the topic and its associates with the ecological systems and the overall environment. The study points out that Tamarix is responsible for water scarcity, species displacement, fire hazards, inhospitality of riparian areas, and altered soil systems. Further, the study argues that control measures have been adopted to terminate and reduce the risks of Tamarix. Overall, this study underlines the requirement of lowering the depletion rate of the underground freshwater source by preventing the excessive water consumption of future threat, Tamarix parviflora trees, which start from the coastal regions and spread to the inner areas of Datça.

Episodic defoliation rapidly reduces starch but not soluble sugars in an invasive shrub, Tamarix spp.

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. 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. 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. 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.

Research of salt tolerance mechanism of sandy shrub Tamarix spp

&lt;p&gt;6.5% of the world's total land area is saline-alkali land, and more than 800 million hectares of saline soil are distributed worldwide. Soil salinization has become an important constraint on global food security and ecological security. &lt;em&gt;Tamarix&lt;/em&gt; is a typical salt-secreting halophyte, which can excrete the salt in the plant from the body. The use of plant resources to transform saline-alkali soils has fundamentally alleviated soil salinization compared with traditional methods. Therefore, the research on the salt tolerance mechanism of tamarisk is very important to alleviate the problem of the shortage of cultivated land resources.&lt;/p&gt;

Adaptive versus non-adaptive responses to drought in a non-native riparian tree / shrub, Tamarix spp

ABSTRACT Rapidly colonizing species often thrive in a wide-range of conditions due to a high degree of phenotypic plasticity that results in populations of “general purpose” genotypes. Alternatively, species with high genetic variation could rapidly respond to forces of selection such that a local population evolves traits that provide an advantage in its local environment. We tested this generalist versus local adaptation paradigm in a widely distributed, recently introduced riparian tree / shrub, Tamarix spp. Using an eighty-day, mid-summer common garden drought experiment, we tested three inter-related hypotheses: 1) stomatal sensitivity to soil water depletion is lower in genotypes from a low-elevation, ephemerally flowing river than genotypes from a low-elevation, perennially flowing river, indicative of local adaptation to hydrological conditions, 2) stomatal sensitivity to soil water depletion is lower in genotypes from high-elevations with regular freeze-thaw exposure than genotypes sourced from locations with no freeze-thaw exposure, indicative of local adaptation to temperature conditions, and 3) differences among genotypes in drought sensitivity are correlated with differences in fine root area to leaf area ratios (Ar:Al). For the most part, results did not support hypothesis 1, but largely supported hypotheses 2 and 3. Specifically, sap-flux scaled canopy transpiration (El) declined 14 days earlier in the low-elevation populations after drought initiation compared to El of the highest elevation population with the highest freeze-thaw exposure. Root area to leaf area ratios of the two low-elevation populations were also only 42% and 55% of Ar:Al in the highest elevation population. Results indicate that the high degree of reported Tamarix hybridization since its introduction to North America has largely produced a swarm of “generalist” genotypes in terms of drought sensitivity. Nevertheless, rapid changes in ecohydrologic conditions may result in some Tamarix populations becoming maladapted sooner to reductions in available water than others in the western US.

An Herbivore-Induced Plant Volatile From Saltcedar (Tamarix spp.) Is Repellent to Diorhabda carinulata (Coleoptera: Chrysomelidae).

The leaf beetle Diorhabda carinulata Desbrochers (Coleoptera: Chrysomelidae) was introduced into the United States in 1999 for classical biological control of the exotic woody invader saltcedar (Tamarix spp. L. [Caryophyllales: Tamaricaceae]). The recent southern expansion of the range of D. carinulata in the United States has precipitated conflict between proponents of biological control of Tamarix and those with concerns over habitat conservation for avian species. Several semiochemicals that mediate aggregations by this species have been reported, but no repellent compounds have been recorded thus far. We now report a repellent compound, 4-oxo-(E)-2-hexenal, induced by adult D. carinulata feeding on saltcedar foliage. Collection of headspace volatiles, gas chromatography mass spectrometry, and electroantennographic analyses identified 4-oxo-(E)-2-hexenal as an insect-induced compound that is antennally active. Behavioral and exposure assays were conducted to test for repellency and toxicity in adults and larvae. Headspace volatiles were also collected from adult males exposed to 4-oxo-(E)-2-hexenal to determine the impact exposure might have on the emission of the aggregation pheromone. 4-Oxo-(E)-2-hexenal elicited electrophysiological responses in adults of both sexes. Behavioral responses indicated repellency across multiple doses for reproductive D. carinulata adults but not in nonreproductive adults. Exposure assays indicated altered behaviors in first instar larvae and adults, but not in third instar larvae. Collection of headspace volatiles indicated that exposure to 4-oxo-(E)-2-hexenal did not alter emission of the D. carinulata aggregation pheromone by adult males. The continued development and field deployment of this repellent compound may provide a new tool for the management of D. carinulata.

Evaluating the impacts of combating-action programs on desertification hazard trends: A case study of Taybad-Bakharz region, northeastern Iran

Abstract In Iran, desertification is usually caused by both nature and humans greedy behaviors such that, more than 75% of the country’s area is dominated by arid zones, and most of the ecosystems are being destroyed due to human activities currently known as the main environmental hazard in Taybad-Bakharz region located in northeastern Iran. Thus, the present study was conducted to evaluate the effects of these measures on the desertification phenomenon generated from climate, soil, vegetation, socio-economic, erosion, and groundwater factors in the Taybad-Bakharz region over the past 40 years (1977–2016). Besides mechanical actions e.g., the establishment of water-saving structures, gabions, and check-dams, a wide array of biological action plans was set out across the prone-regions over the last few years such as vegetation restoration plans utilizing resistant species like Haloxylon persicum and Tamarix spp. Results indicated an ascending trend in desertification hazard (from 2.17 to 2.25) despite the supports devoted to environmental protection and management of desertification. Despite partially stabilized dunes and decreased Aeolian activities, the lack of attention to the anthropogenic activities such as agricultural practices, mining, over-pumping the groundwater resources, overgrazing, etc., either directly or indirectly related to people’s livelihood has led to a rise in desertification hazard.

Invasive Saltcedar and Drought Impact Ant Communities and Isopods in South-Central Nebraska.

The establishment and spread of non-native species often results in negative impacts on biodiversity and ecosystem function. Several species of saltcedar, Tamarix spp. L., have been recently naturalized in large portions of the United States where they have altered plant and animal communities. To test the prediction that saltcedar negatively affects invertebrates, we measured ant genera diversity and the activity density of the exotic isopod Armadillidium vulgare Latrielle (Isopoda: Oniscoidea) for 2 yr using pitfall traps located within 30 5-m2 plots with or without saltcedar at a south-central Nebraska reservoir. From 2005 to 2006, we collected 10,837 ants representing 17 genera and 4,953 A. vulgare. Per plot, the average number of ant genera was not different between saltcedar (x̅ = 3.9) and non-saltcedar areas ( x̅ = 3.9); however, saltcedar plots were compositionally different and more similar from plot to plot (i.e., they had lower beta diversity than control plots) in 2005, but not in 2006. Isopods were likewise temporally affected with higher activity density (+89%) in control plots in 2005, but higher activity density (+27%) in saltcedar plots in 2006. The observed temporal differences occurred as the drought that initially enabled the saltcedar invasion became less severe in 2006. Combined, our results suggest that invertebrate groups like ants, which are generally omnivorous, may be better equipped than more specialized taxa like detritivores to withstand habitat changes due to invasions by non-native species, especially during extreme weather events such as prolonged droughts.

Encuentros y desencuentros de los comités de ética con la investigación ambiental y artística: ¿cómo pensar una forma de articulación?

En este artículo se describen algunas de las dificultades presentadas cuando se postulan, para su evaluación y aval de parte de comité de ética, proyectos de investigación de áreas de conocimiento con lenguajes y lógicas que se alejan de la investigación clínica. Se presentan dos casos, cuyos objetos de conocimiento tienen epistemologías disímiles a los que usualmente se deliberan en estas instancias. El primero trata de una instalación de arte que permitió el estudio del vínculo afectivo entre seres humanos y ratones de laboratorio. Se analizan las solicitudes puntuales de parte del comité de ética y las respuestas emitidas por la artista para obtener su aprobación. El segundo consiste en la introducción de la planta invasora Támarix spp en el ecosistema ribereño de los Estados Unidos, convirtiéndose en el sitio de anidamiento del ave atrapamoscas Empidonax trailii extimus en peligro de extinción. Este fenómeno suscitó cuestiones éticas desafiantes para los restauradores ecológicos en su búsqueda por el significado de lo natural. Se concluye que los comités de ética podrían acoger la perspectiva de los conocimientos situados de Donna Haraway y la teoría del actor-red de Bruno Latour, que sugieren que, en el afán de alcanzar una universalidad, la ciencia ha tendido a buscar una estandarización reduccionista de la diversidad de significados.

Phenology and Abundance of Northern Tamarisk Beetle, Diorhabda carinulata Affecting Defoliation of Tamarix

Timing and spatial dynamics of tamarisk (Tamarix spp. L.) defoliation by the biological control agent Diorhabda carinulata (Desbrochers) were evaluated. Relative abundance of D. carinulata and the phenology of tamarisk along the San Juan and Colorado rivers were recorded in 2011–2012. D. carinulata began reproducing in the spring when temperatures were >15°C. Variation in spring temperature-rise affected the timing of development of larvae of the first summer generation and initial defoliation of tamarisk at each site. Shortening day lengths in mid- to late-summer cued D. carinulata to enter reproductive diapause resulting in cessation of defoliation. The critical day length for inducing reproductive diapause was 33–47 minutes shorter than that of populations of D. carinulata released into North America in 2001. Variation in spring temperature-rise combined with timing of shortening day length resulted in differences in D. carinulata voltinism per site. During the active season, larvae were less likely to establish in areas where defoliation was >70%. Lack of reestablishment of larvae led to temporary loss of D. carinulata from the locations and allowed tamarisks to sprout new canopies. Defoliation of tamarisk was dictated by environmental cues and abundance of D. carinulata, and in turn large amounts of defoliation negatively affected abundance of D. carinulata.

Native species recovery after reduction of an invasive tree by biological control with and without active removal

Removal of invasive species is often an important, if not central, component of many riparian restoration projects, however little is known about the response of plant communities following this practice. In particular, active control of the exotic, dominant tree Tamarix spp is often a focus of riparian restoration, much of which occurring against a backdrop of biological control by a folivore beetle. Our research employed controls in both time and space to investigate the impact of active Tamarix removal methods in sites subjected to biological control in 40 sites sampled three times over a period of five years. We found that reduction in Tamarix cover was much greater over time with active means of removal, however the native understory increased both with and without active removal. Importantly, change in the relative cover of understory native species was significantly negatively correlated with change in Tamarix cover, with those sites that received a combination of low-disturbance-mechanical, chemical and bio-control showing greater increases in native understory dominance than those sites with biological control alone or high-disturbance mechanical control. Sites with only bio­control still contained 10% live Tamarix cover >7 yr since the beetle was released there. Taken together, these results suggest that the reduction of this exotic tree, even by biological control that leaves some canopy intact, can facilitate recovery of the native plant community. As such, this study supports the Field of Dreams hypothesis that states that once niches are restored, native plants should be able to recolonize.

Acceptability ofDiorhabda carinulata, an Introduced Biological Control Agent ofTamarix, as Prey for Selected Resident Native Arthropod Predators

Although biological control agents are imported without the constraints exerted by their native natural enemies, many native, generalist arthropod predators might use the new food source after release in the field. Predation by native arthropods is a potential obstacle to establishment of Diorhabda spp. as a biological control agent against saltcedar, Tamarix spp. Arboreal predaceous insects were surveyed at the Great Salt Plains National Wildlife Refuge to identify possible predators that could affect establishment of the northern tamarisk beetle, Diorhabda carinulata (Desbrochers), in Oklahoma. Results of the survey showed that 57% of the arthropods were represented by five insects, Zelus tetracanthus (Stal) (Hemiptera: Reduviidae) (21%); several species of Chrysoperla (Neuroptera: Chrysopidae) (11%); the insidious flower bug, Orius insidiosus (Say) (Hemiptera: Anthocoridae) (10%); Collops quadrimaculatus (F.) Coleoptera: Melydridae) (8%); and the sevenspotted lady beetle, Coccinella septempunctata L. (Coleoptera: Coccinellidae) (6%), in saltcedar stands. No-choice feeding studies demonstrated that eggs and larvae of D. carinulata were accepted prey for larvae of Chrysoperla rufilabris (Burmeister) and sevenspotted lady beetle adults but not larvae. Northern tamarisk beetle larvae were accepted prey for Z. tetracanthus.

Caracterización palinológica de mieles del Valle de Mexicali, Baja California, México

The profitability of apiculture and the health of bee populations depend on landscapes rich in nectariferous and polleniferous flowers. Therefore it is clear that knowledge on local bee flora constitutes the basic information necessary to determine the apiculture potential of a region. Nevertheless, there is no research to date showing the floral sources of honey in the State of Baja California. Thus a melissopalynological study of the honey produced in the Valley of Mexicali, Baja California was undertaken to identify the main sources of pollen and nectar utilized by Apis mellifera and determine the botanical origin during the two principal harvest periods around year. The pollen of 52 honey samples was analyzed, these were collected from 13 apiaries on June and August of 2010 and of 2011. To identify the types of pollen, a reference collection was made containing 150 species pollen prepared via the acetolysis method. 78 types of pollen were identified, corresponding to 33 families. 65% of the honeys were unifloral, mainly from Tamarix spp. , and Prosopis spp. , and to a lesser extent of Pluchea sericea. Sysimbrium irio , Myrtaceae , Phoenix dactylifera , Coriandrum sativum , and Washingtonia filifera were found a single time. Prosopis spp. honeys were most abundant in June harvests, while Tamarix spp. honeys were the most common august harvests. Quantitative analysis allowed to allocate 52% of the samples on class III, 34% on class II, 8% on class V, 4% on class IV and 2% on class I. According to the analysis carried out, it is concluded that the main nectar sources used by A. mellifera in the Valley of Mexicali are Tamarix spp. Propsopis spp. and P. sericea , which are also the most representative elements of honeys.

Tamarix ramosissima stand evapotranspiration and its association with hydroclimatic factors in an arid region in northwest China

There is currently only limited quantitative data available on riparian forest evapotranspiration (ET) of saltcedar (Tamarix spp.) in northwest China. We measured ET over a two year period using eddy covariance (EC) in Tamarix ramosissima stands in the lower Heihe River basin, China. We found that during the growing season, measured ET was approximately 520 mm yr−1 with a mean of 2.82 mm d−1. This was comparable to results from the lower Tarim River basin in central Asia where Tamarix spp is a native species. Comparisons between measured and estimated daily ET yielded an underestimation of approximately 30%, which could be partly due to errors in EC and nighttime transpiration. Whether directly measured or estimated, T. ramosissima stands were lower in its native environments compared to the western U.S.. Moreover, environmental parameters, such as climate and soil water content, accounted for at least 68%–78% of hourly and daily ET variation, respectively. Soil water factors were more important in accounting for daily ET variation than climate factors, but the opposite was true on a hourly timescale. Results showed that lower water use in T. ramosissima stands in the central Asia likely resulted from its long-term adaptation to hydroclimatic regimes.

Effect of salt and drought on growth, physiological and biochemical responses of two Tamarix species

Abstract: Tamarix trees are considered of particular interest for afforestation and reforestation of degraded areas prone to salinity and drought. In this study, a comparison of the performance and physiological responses of two species of Tamarix grown in saline and dried soils was carried out. Stem cuttings of T. aphylla and T. jordanis were collected from a location in the Negev desert and the plantlets obtained were subjected to four different soil treatments under semi-controlled conditions for 14 days. The treatments were: fresh water (C); salt (S: 150 mM of NaCl); drought (D: 50% field capacity); and a combined stress (DS: 150 mM of NaCl + 50% FC). Results showed a higher tolerance to salt stress of T. jordanis as compared with T. aphylla. The maintenance of high amount of cell carbohydrates, the high capacity of carbon assimilation and the active growth were considered as markers of salt tolerance in Tamarix spp. T. aphylla showed better performances in terms of growth and biomass production than T. jordanis in dry conditions. The high accumulation of sugars found in the leaves of T. aphylla under mild drought is considered a mechanism of acclimatization. The combined stress (salt+drought) lowered the performance of plants as compared to salt and drought stress applied alone. The possible role of the accumulation of proline observed in the leaves of both species under stressful conditions is discussed.

Evapotranspiration and its main controlling mechanism over the desert riparian forests in the lower Tarim River Basin

Evapotranspiration (ET) and its controlling mechanism over the desert riparian forests in arid regions are the important scientific basis for the water resources managements of the lower reaches of the inland rivers of China. Nearly three years of continuous measurements of surface ET, soil water content at different depths and groundwater table over a typical Tamarix spp. stand and a typical Populus euphratica stand were conducted in the lower reach of the Tarim River. The ET seasonal trends in the growing season were controlled by plant phenology, and ET in non-growing season was weak. The diurnal variations of ET resulting from the comprehensive effects of all atmospheric factors were significantly related with reference ET. The spatial pattern of ET was determined by vegetation LAI, more vegetation coverage, more ET amount. Groundwater is the water source of surface ET, and the soil water in shallow layers hardly took part in the water exchange in the groundwater-soil-plant-air system. The temporal processes of ET over the Tamarix stand and the Populus stand were similar, but the water consumption of the well-grown Populus euphratica was higher than that of the well-grown Tamarix spp. Further analysis indicates that plant transpiration accounts for most of the surface ET, with soil evaporation weak and negligible; groundwater table is a crucial factor influencing ET over the desert riparian forests, groundwater influences the processes and amounts of ET by controlling the growth and spatial distribution of desert riparian forests; quantifying the water stress of desert riparian forests using groundwater table is more appropriate, rather than soil water content. Based on the understanding of ET and water movements in the groundwater-soil-plant-air system, a generalized framework expressing the water cycling and its key controlling mechanism in the lower reaches of the inland rivers of China is described, and a simple model to estimate water requirements of the desert riparian forests is presented.

Interactions among Tamarix (Tamaricaceae), Opsius stactogalus (Cicadellidae), and Litter Fungi Limit Riparian Plant Establishment

One of the most significant plant invasions in the U.S. has been that of the Old World genus Tamarix. While Tamarix spp. is widely studied, surprisingly little is known about more complex trophically-linked community mechanisms influencing under-canopy succession. We investigated multi- trophic interactions among Tamarix spp., nonnative host-specific Opsius stactogalus leafhopper distribution and honeydew production, and the Tamarix spp. canopy floor fungal assemblage. We quantified leafhopper abundance and honeydew throughfall, and tested under-canopy seed viability and seedling mortality across a 1600 m elevation gradient in the lower Colorado River basin in 2007. We conducted field and laboratory experiments in 2007-08 to test the effects of Tamarix spp. litter fungi, synthetic honeydew, and the combination of those variables on germination and seedling survivorship of three common, co-occurring phreatophyte (riparian groundwater-dependent plant) species. Tamarix spp. litter and honeydew treatments reduced understory seed viability and recruitment of two native, woody riparian species (Populus fremontii and Baccharis salicina), as well as Tamarix spp. Four major patterns were detected. 1) Litter fungi alone and synthetic honeydew alone reduced seed viability and seedling survivorship of all three species by two- to four-fold. 2) Synthetic honeydew + litter reduced Tamarix spp. and P. fremontii seed and seedling viability by up to 10-fold. 3) Synthetic honeydew concentration and seedling mortality were positively related among all three plant species. 4) B. salicina was less susceptible to all treatments than Tamarix spp. and P. fremontii. These results indicate that complex interactions among nonnative Tamarix spp., nonnative Opsius leafhopper honeydew production, and soil fungi may influence riparian phreatophyte recruitment and succession.

Bioenergy that supports ecological restoration

Bioenergy development can offer beneficial ecological and economic synergies through the expansion of ecological 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 53 000–180 000 Mg of biomass per year for several decades. Thermochemical analyses revealed that the elevated nitrogen, sulfur, and ash content 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.

Life History Characteristics ofDiorhabda CarinulataUnder Various Temperatures

Tamarisk leaf beetles, Diorhabda spp., have been released in the western United States as a biological control agent for the invasive weed Tamarix spp. There have been a few studies on the life cycle, host preferences, and field observations of Diorhabda; however, their ecophysiological characteristics under various temperature regimes are not clearly understood. In this study, life history characteristics such as growth, fecundity, and mortality of Diorhabda Carinulata (Desbrochers), the species established in the Colorado River basin, were investigated under various temperatures. Beetles were housed at various temperatures (room, constant high, and variable high) and their life cycle from eggs to reproductive adult was observed. Body size at various larval and adult stages, as well as their developmental time decreased with increasing temperature. Between the two temperature treatments, beetles at diurnally fluctuating temperature (variable high treatment) grew slower and produced fewer eggs per clutch when compared with the constant high treatment. Despite smaller in size, beetles grew fastest at the constant high temperature and produced most eggs per clutch compared with the other two treatments. Overall, severely high temperatures seem to have a debilitating effect on Diorhabda at early larval stages with nearly 50% mortality. The study has potential implications for the tamarisk beetle biocontrol program in the southwestern United States.