Rubus Armeniacus Research Articles

Evaluating potential phytotoxicity of erythritol solution, a novel control method for Drosophila suzukii, in blueberry, cherry, and wild Himalayan blackberry

Drosophila suzukii, commonly referred to as spotted-wing drosophila, is a recent pest of small and stone fruits across the United States. While its control is commonly achieved through broad-spectrum pesticides, these chemicals are often harmful to beneficial insects. A new candidate for control is erythritol, a non-nutritive sugar alcohol with insecticidal properties. Erythritol solutions with a sucrose (E:S) or sucralose (E:Sul) phagostimulant reduce larval infestation and deter oviposition when applied to fruits pre-harvest, but lead to spotting and other damage to sprayed plant leaves. Our objectives were to determine the extent and physiological impacts of the damage in several plant systems and assess the role of individual components in potential phytotoxicity. In the first year, bulk or lab-grade erythritol were combined with a sucrose or sucralose phagostimulant to evaluate the effects of the solutions and a water control on visible damage, stomatal conductance, chlorophyll fluorescence, relative water content, and osmolality in blueberry, cherry, and blackberry leaves. When bulk erythritol did not have discernible impacts, second year trials evaluated solutions of lab-grade erythritol with a phagostimulant and solutions of individual chemicals on leaf damage and physiological factors. Solutions of E:S and E:Sul caused the greatest visible damage, but damage was highly variable between years, treatments, and plant systems. There were no consistent plant physiological effects associated with any formulation. These results suggest that while visible leaf damage may be a dose-dependent effect of erythritol solutions, the lack of associated physiological impacts make it a viable candidate for further testing.

A complex biosystematic approach to reveal evolutionary and diversity patterns in West Asian brambles (Rubus subgen. Rubus, Rosaceae)

West Asia, with its high mountain ranges and glacial refugia, stands out as a biodiversity hotspot for various plant taxa, including the taxonomically complex Rubus subgen. Rubus. Despite this significance, our understanding of the evolutionary processes shaping this group in the region has been limited. We employed an integrative approach combining flow cytometry, Sanger sequencing of two plastid regions, microsatellite genotyping, and double digest restriction-site associated DNA sequencing to characterize evolutionary and diversity patterns in West Asian brambles. We identified four diploid and two sexual tetraploid species, with the remaining diversity comprising apomictic tetra- and triploids, mostly belonging to R. ser. Discolores, and sexual pentaploid hybrids/hybridogens derived from R. caesius. Rubus dolichocarpus, newly reported here as diploid, emerged as a significant ancestor for many polyploids. Most apomictic genotypes are locally distributed and only three genotypes exhibit extremely large ranges from Armenia to Kyrgyzstan and from Georgia to Iran. These genotypes are probably of an ancient (Pleistocene) European origin and likely laid the foundations for the evolution of apomicts in West Asia, whose diversification was subsequently boosted by the genetic contribution of sexual taxa. DNA markers confirmed the West Asian origin of Rubus armeniacus, a globally significant invasive species, yet rare in its native range. We report on the first indigenous occurrence of this species based on microsatellite genotyping. Our findings contribute to filling existing gaps in understanding the evolution and diversity of Rubus subgen. Rubus in West Asia.

Process optimization for green synthesis of silver nanoparticles using Rubus discolor leaves extract and its biological activities against multi-drug resistant bacteria and cancer cells

Multi-drug resistant (MDR) bacteria are considered a serious public health threat. Also, increasing rate of resistance to anticancer drugs, as well as their toxicity, is another point of concern. Therefore, the new antibacterial and anticancer agents are always needed. The synthesizing silver nanoparticles (AgNPs) using medicinal plants, is an effective approach for developing novel antibacterial and anticancer agents. Rubus discolor, a native species of the Caucasus region, produces leaves that are typically discarded as a by-product of raspberry production. The present study has focused on optimizing the green synthesis of AgNPs using R. discolor leaves extract through response surface methodology. The optimal values for AgNPs synthesis were an AgNO3 concentration of 7.11 mM, a time of 17.83 h, a temperature of 56.51 °C, and an extract percentage of 29.22. The production of AgNPs was confirmed using UV–visible spectroscopy (λmax at 456.01 nm). TEM analysis revealed well-dispersed AgNPs (an average size of 37 nm). The XRD analysis confirmed the crystalline structure. The EDX detected a strong peak at 3 keV corresponded to Ag. The zeta potential value (− 44.2 mV) indicated the stability of nanoparticles. FT-IR spectra showed the presence of various functional groups from plant compounds, which play an important role in the capping and bio-reduction processes. The AgNPs revealed impressive antibacterial activities against MDR Escherichia coli and Pseudomonas aeruginosa (MIC ranging from 0.93 to 3.75 mg ml−1). The phytochemical analysis indicated the presence of phenolics, tannins, and flavonoids on the surface of AgNPs. They also showed significant cytotoxic effects on A431, MCF-7, and HepG2 cells (IC50 values ranging from 11 to 49.1 µg ml−l).

Anti-Glioblastoma Potential and Phenolic Profile of Berry Juices

Glioblastoma is one of the most aggressive and lethal brain tumors. Due to the failure of conventional chemotherapies and targeted drugs pursuit of natural, less toxic agents is on the rise as well as their utilization in glioblastoma treatment. Consequently, this study explores the antiproliferative potential of selected berry juices (wild blackberry (Rubus discolor), dwarf elderberry (Sambucus ebulus), and raspberry (Rubus idaeus)) on glioblastoma cells (U87-MG and GBM43) in comparison to temozolomide. The juices were assessed for total phenolic content, proanthocyanins, polyphenol profiles, and antioxidant activity. Wild blackberry and dwarf elderberry juices exhibited higher total polyphenols, proanthocyanins, and monomeric anthocyanins compared to raspberry juice. HPLC analysis revealed distinctive anthocyanins, flavonoids, and phenolic acids in each juice. With the DPPH assay, the highest antioxidant potential had wild blackberry juice, while with other assays dwarf elderberry juice had the highest potential. Antiproliferative effects were dose-dependent, with wild blackberry juice demonstrating the highest potency, surpassing temozolomide in inhibiting GBM43 cell proliferation. In U87 cells, all juices exhibited antiproliferative effects, with wild blackberry showing the strongest impact. This study highlights the potential of wild blackberry juice as a potent natural agent against glioblastoma, suggesting its superiority over the conventional treatment.

Sipping on Nectar: Butterflies and Flowers in Oak Savannas on Vancouver Island, British Columbia

Photo 1. View of a Garry oak savanna field site in Camrose Park, Victoria, BC, Canada. Oak savannas in the region are characterized by rocky outcroppings, a dense understory of forbs, and an open canopy of mostly Garry oak trees (Quercus garryana) mixed in with Douglas Firs (Pseudotsuga menziesii) and Arbutus (Arbutus menziesii). In front of the treeline, the nectar-less yellow flowers of invasive Scotch Broom (Cytisus scoparius) can be seen. Photo credit: Stephanie A. Rivest. Photo 2. Examples of flowering plants recorded in Garry oak savannas around Victoria, BC. Western Buttercup (top left panel: Ranunculus occidentalis) and Sea Blush (top right panel: Plectritis congesta) are native to the region, while Himalayan Blackberry (bottom right panel: Rubus armeniacus) and Cornflower (bottom right panel: Centaurea cyanus) are non-native. Photo credit: Stephanie A. Rivest. Photo 3. A native Propertius Duskywing (Erynnis propertius) butterfly foraging for nectar on a native White Brodiaea (Triteleia hyacinthine) flower in an oak savanna in Victoria, BC. Photo credit: Stephanie A. Rivest. Photo 4. A native Painted Lady (Vanessa cardui) butterfly foraging for nectar on a native Oceanspray (Holodiscus discolor) flower in an oak savanna in Victoria, BC. Photo credit: Stephanie A. Rivest. Photo 5. A native Lorquin's Admiral (Limenitis lorquini) perched on a researcher's hand during a field survey of an oak savanna in Victoria, BC. The butterfly's proboscis explores the researcher's skin, hoping to collect the sodium from sweat. Photo credit: Stephanie A. Rivest. Source paper: These photographs illustrate the article “Flowering phenology influences butterfly nectar foraging on non-native plants in an oak savanna” by Stephanie A. Rivest, E.M. Wolkovich, and Heather M. Kharouba published in Ecology. https://doi.org/10.1002/ecy.4004

Genomics of the "tumorigenes" clade of the family Rhizobiaceae and description of Rhizobium rhododendri sp. nov.

Tumorigenic members of the family Rhizobiaceae, known as agrobacteria, are responsible for crown and cane gall diseases of various crops worldwide. Tumorigenic agrobacteria are commonly found in the genera Agrobacterium, Allorhizobium, and Rhizobium. In this study, we analyzed a distinct "tumorigenes" clade of the genus Rhizobium, which includes the tumorigenic species Rhizobium tumorigenes, as well as strains causing crown gall disease on rhododendron. Here, high-quality, closed genomes of representatives of the "tumorigenes" clade were generated, followed by comparative genomic and phylogenomic analyses. Additionally, the phenotypic characteristics of representatives of the "tumorigenes" clade were analyzed. Our results showed that the tumorigenic strains isolated from rhododendron represent a novel species of the genus Rhizobium for which the name Rhizobium rhododendri sp. nov. is proposed. This species also includes additional strains originating from blueberry and Himalayan blackberry in the United States, whose genome sequences were retrieved from GenBank. Both R. tumorigenes and R. rhododendri contain multipartite genomes, including a chromosome, putative chromids, and megaplasmids. Synteny and phylogenetic analyses indicated that a large putative chromid of R. rhododendri resulted from the cointegration of an ancestral megaplasmid and two putative chromids, following its divergence from R. tumorigenes. Moreover, gene clusters specific for both species of the "tumorigenes" clade were identified, and their biological functions and roles in the ecological diversification of R. rhododendri and R. tumorigenes were predicted and discussed.

First records of adventive populations of the parasitoids Ganaspis brasiliensis and Leptopilina japonica in the United States

We report the first known incidence of two parasitoid species of the invasive pest, Drosophila suzukii (Matsumura) (Diptera: Drosophilidae), in the United States (US). The discovery of Ganaspis brasiliensis (Ihering) (Hymenoptera: Figitidae) and Leptopilina japonica (Novković & Kimura) (Hymenoptera: Figitidae) in northwestern Washington State (US) was made shortly after their discovery in nearby southwestern British Columbia (Canada), indicating that contiguous populations of these species are established in both countries. The first specimen of L. japonica from Washington was collected in the fall of 2020, when it was found in a rice wine/orange juice trap deployed to survey for Vespa mandarinia Smith (Hymenoptera: Vespidae). Subsequent examination of trap contents from the 2020–2021 seasons indicated the presence of both L. japonica and G. brasiliensis. In September of 2021, live collections of both G. brasiliensis and L. japonica were made, reared from D. suzukii-infested Himalayan blackberry in Whatcom County, WA. Adult parasitoid identifications were based on morphology and COI DNA barcodes. All sequenced specimens to date from Washington and British Columbia belong to the G1 group of G. brasiliensis, the only group approved for release as a classical biological control agent in the US. This study provides an example of how even small changes in the geographic range of a natural enemy, now extending across an international border, may have significant consequences for the future of a biological control program.

First Report of Gnomoniopsis idaeicola Causing Cane Wilt and Canker in Commercial Blackberry Fields in Oregon.

Oregon is the leading producer of blackberries in the United States (USDA 2021). In November 2020, we visited a seven-year-old, 5.6 HA field of thornless trailing cultivar 'Columbia Star' in Marion County, Oregon in response to grower reports of rapid plant death that they called 'Blackberry Collapse.' The pattern of disease in the field was semi-circular patches of dead plants. We estimate that ca. 17% of the plants were killed. Symptoms included fewer and stunted primocanes, floricane reddening, premature floricane senescence, or elliptical or irregular brown to purple cane lesions often near the base of necrotic petioles clasping the cane. Twenty-two cane lesions were collected, surface-disinfested, and placed on potato dextrose agar with streptomycin. In addition to common Rubus cane pathogens (Kalmusia coniothyrium, Botrytis spp., Diaporthe spp., and Seimatosporium lichenicola), Gnomoniopsis idaeicola was isolated from 23% of the samples. After isolation of G. idaeicola from 'Columbia Star', we also isolated the pathogen from symptomatic 'Black Diamond' blackberry in fields in Washington and Linn Counties in Oregon. G. idaeicola grew as white- to cream-colored circular colonies on the agar surface with sparse to dense aerial hyphae. Some isolates produced cream-colored exudate from irregular conidiomata. Conidia were single-celled, hyaline, oval to ellipsoid, and ranged from 4.9 to 6.9 µm long and 1.2 to 2.5 µm wide (n = 100). Perithecia and ascospores were not seen on canes or in culture; molecular methods were used to identify the fungus. Genomic DNA was extracted from nine isolates and β-tubulin, ITS region, and tef-1α were amplified using the primers and conditions described by Walker et al. (2010). Amplicons were Sanger sequenced in both directions by the Core Facilities of the Center for Quantitative Life Sciences of Oregon State University, Corvallis, OR. Sequences were deposited in GenBank (β-tubulin OK539758-OK539766; ITS OK348854-OK348862; tef-1α OK539767-OK539775). β-tubulin sequences (737 bp) were 100% identical to sequence of G. idaeicola from Rubus procerus, Oregon (GU320783). ITS sequences (518 bp) were 99.2 to 100% identical to G. idaeicola CBS125674T (GU320796). tef-1α sequences (860 bp) were 99.9 to 100% identical with reference sequences of G. idaeicola. Phylogenetic analyses of concatenated sequences using Tamura-Nei neighbor-joining (Tamura et al. 2004) confirmed identity. Pathogenicity of G. idaeicola isolates was tested in repeated experiments on four to five detached 'Black Diamond' primocanes and potted 'Columbia Star' plants with 4 mm hyphal plugs placed on fresh wounds and wrapped in parafilm; controls were treated with sterile agar plugs (Ellis et al. 1984; Stevanović et al. 2019). By 14 days, in each experiment, expanding necrotic lesions were observed on canes inoculated with G. idaeicola, but not with sterile agar plugs. ITS-sequence of fungi isolated from lesions confirmed identity as G. idaeicola, fulfilling Koch's postulate. G. idaeicola was described as a new species by Walker et al. (2010) from perithecia collected from wild Rubus spp. in the Pacific Northwest. Despite its presence on native Rubus, G. idaeicola has not been reported in commercial blackberry fields in OR. Stevanović et al. (2019) identified G. idaeicola as an important pathogen causing canker, wilt, and death of blackberry in Serbia. Surveys of Oregon blackberry fields for G. idaeicola are ongoing, along with research on the epidemiology and management of this emerging pathogen.

Epidemiology of Grapevine Red Blotch Disease Progression in Southern Oregon Vineyards

Grapevine red blotch disease (GRBD) is an emerging disease caused by grapevine red blotch virus (GRBV). It is widespread in most United States winegrape production regions and differential spread dynamics have been reported between the regions. This study surveyed eight vineyard sites in southern Oregon over four years for the progression of GRBD incidence. The vineyards included five sites that were five years or older and three sites that were three-years-old. The disease incidence in the older blocks ranged from 2.81 to 58.78%, while in the younger blocks it ranged from 0.29 to 1.11%. Some vineyards implemented frequent disease scouting, removing infected vines and replanting. The disease incidence in these blocks remained &lt;5% over the survey period. However, in vineyards with no roguing and replanting, the disease incidence increased nearly 30-fold after three years. We analyzed the spatial distribution of the disease in vineyards surveyed in 2020 and found that the disease distribution is highly aggregated based on Spatial Analysis by Distance Indices (SADIE). In a separate study, we also tested the GRBV infection status of asymptomatic vines next to symptomatic vines to inform decision-making when roguing and replanting. Out of 410 asymptomatic vines surrounding 41 symptomatic vines, only two tested positive for GRBV. Additionally, in 2020 and 2021, we tested the GRBV status of previously identified possible alternative host species: blackberries (<i>Rubus armeniacus</i>) and wild/feral grapes (<i>Vitis</i><i>riparia</i>) collected from areas surrounding the four survey sites. GRBV was present in 10 to 70% of wild grape samples in both years and in 10% of the blackberry samples in 2020. However, the virus titer was low in blackberry samples and it was not detected in 2021 samples. These results indicate the potential importance of wild grapes as alternative hosts on GRBD incidence and spread in southern Oregon vineyards, while blackberry is unlikely to be an alternative host with epidemiological significance.

SECONDARY METABOLITES EXTRACTION USING POTENT BIOLOGICALS &amp; PHYTOCHEMICAL SCREENING

Antioxidants present in the diet may have a significant effect on the prophylaxis and progression of various diseases associated with oxidative stress like cancer diabetes, cardiovascular and neurodegenerative. Berries and fungal species contain a range of secondary metabolites with antioxidant properties, including phenolic compounds. The objective of this study is to extract secondary metabolites from biologicals (wild berries and fungal species from the Himalaya region) and to conduct the preliminary phytochemical screening, total flavonoid and phenolic contents assays of various solvent extracts.&#x0D; In this study, wild species were collected from the Himalayan region and extracted with different solvents by Soxhlet extraction. Phytochemical screening was carried out using standard procedures, total flavonoid content was measured by the aluminum chloride colorimetric assay and total phenolic content was estimated spectrophotometrically by the Folin-Ciocalteau method. Preliminary phytochemical screening reveals that except a few all extracts show the presence of alkaloids, tannin, carbohydrate, glycosides phenol, and flavonoid. Only Water, methanolic, and Chloroform extract of Rubus indicus (RIW, RIM, RIC) and water, methanolic extract of Solanum nigrum (SNW and SNM) contains steroids. Saponins are found only in extracts of Solanum nigrum and Morchella esculenta. Water extract of Rubus armeniacus, Solanum nigrum, Morchella esculenta and methanolic extract of Rubus indicus, Lycium barbarum (RAW, SNW, MEW, RIM, and LBM) shows higher content of flavonoid and phenol.&#x0D; Methanolic extract of Lycium barbarum and Rubas armeniacus has the richest content of phenolics and flavonoids i.e. (102.16 mg GAE/g and 2.95 mg QE/g) respectively, on the contrary, hexane extract of Morchella esculenta and chloroform extract of Lycium arbarum was the least i.e. (6.64 mg GAE/g and 0.59 mg QE/g). All the extracts were not significantly different from one another (p &gt; 0.05). It can be hypothesized that the high contents of phenolic compounds of these sample extracts indicated that these compounds contribute to the antioxidant activity and can be regarded as promising plant species for natural sources of radical scavenging activity with potential value for the treatment of many life-threatening diseases.

Rubus armeniacus (Himalayan blackberry)

This datasheet on Rubus armeniacus covers Identity, Overview, Distribution, Dispersal, Diagnosis, Biology &amp; Ecology, Environmental Requirements, Natural Enemies, Impacts, Uses, Prevention/Control, Further Information.

Effect of extraction solvents on total phenolic compound, lipid peroxidation, antioxidant and cytotoxic activity of leaves of Rubus armeniacus (Himalayan blackberry)

Effect of extraction solvents on total phenolic compound, lipid peroxidation, antioxidant and cytotoxic activity of leaves of Rubus armeniacus (Himalayan blackberry)

Phenolic profile and biological potential of wild blackberry (Rubus discolor) fruits

The berries of Rubus discolor are considered a rich source of phytochemicals which could play an important role in the prevention of prevalent contemporary chronic diseases. Thus, the goal of the presented study was to determine the profile of phenolic acids and anthocyanins of aqueous and ethanol extracts of R. discolor fruit, and their free radical scavenging, antiproliferative, antidiabetic and antimicrobial activities. LC-MS/MS analyses confirmed the presence of 11 phenolic acids with protocatechuic and gallic acids being the major compounds. Additionally, cyanidin- glucoside/galactoside was the most abundant among the five identified anthocyanins. The ethanol extract was more efficient in scavenging free radicals than the aqueous extract. The absence of antiproliferative activity was observed for both extracts. However, they inhibited carbohydrate hydrolysing digestive enzymes associated with type-2 diabetes. Furthermore, the obtained results for ?-glucosidase inhibitory activity (IC50 values 44.52 and 80.72 ?g/mL, for the aqueous and ethanol extracts, respectively) indicate significantly higher activity than the positive control, GlucobayR (233.38 ?g/mL). The ethanol extract was more effective against all of the examined bacteria (Bacillus cereus, Staphylococcus aureus and Enterobacter cloacae) than the aqueous extract. On the contrary, the aqueous extract showed better antifungal properties, particularly against Trihoderma viride and Penicillium verrucosum var. cyclopium. The quantified phenolics and presented bioactivities of R. discolor fruit extracts candidate them as a potential source of bioactive compounds which might be used in the food, pharmacy and cosmetic industries.

Colonization of Wild Blackberry Plants in California by Fusarium oxysporum f. sp. mori.

Fusarium oxysporum f. sp. mori, the causal agent of Fusarium wilt of blackberry, was first reported in California and Mexico in 2016. A limited survey of the population revealed this pathogen to be one of the most diverse formae speciales of F. oxysporum. We explored the possibility that strains of F. oxysporum pathogenic to commercial blackberry could also be recovered from wild blackberry (Rubus spp.) in California. For this purpose, wild Rubus species in blackberry nurseries, fruit production fields, and nearby areas were collected between 2017 and 2019. Thirty-four isolates of F. oxysporum were recovered from asymptomatic Rubus armeniacus and Rubus ursinus plants. Based on sequence of the translation elongation factor 1-α, somatic compatibility, and pathogenicity to blackberry, 16 isolates were confirmed as F. oxysporum f. sp. mori. These isolates were associated with three somatic compatibility groups, one of which was first identified in this study. Recovery of the pathogen confirmed that wild blackberry plants can act as a reservoir of inoculum of F. oxysporum f. sp. mori and that it can move from wild blackberry plants to commercial cultivars or vice versa.

New Records of Vascular Plant Distribution in the Polish Part of the Lithuanian Lakeland, North-Eastern Poland

AbstractThe paper presents new localities of 15 vascular plants recorded in the Polish part of the Lithuanian Lakeland, north-eastern Poland in 2017–2018, using the ATPOL cartogram method. Crepis capillaris, Diplotaxis tenuifolia, Eragrostis albensis, Matthiola longipetala, Oenothera fruticosa, Oenothera glazioviana and Rubus armeniacus are listed as new species for the regional flora.

Biosystematic revision of the native and naturalised species of Rubus L. (Rosaceae) in the Cape Floristic Region, South Africa

Rubus L. is a highly diverse and taxonomically complex genus with a worldwide distribution. Although southern Africa is not a major centre of Rubus diversity, a number of indigenous and naturalised taxa have been recorded from the region, although their taxonomy, nomenclature and evolution are either confused or poorly studied at best. This paper represents the first results of a wider project focusing on the biosystematics of the southern African Rubus flora, and presents a taxonomic revision of the brambles of the Cape Floristic Region, including an estimation of ploidy levels. A total of eight taxa are recognised, including the two indigenous taxa R. pinnatus and R. rigidus agg., the four introduced species R. armeniacus, R. bergii, R. rosifolius and R. titanus, and two hybrids between indigenous and introduced taxa. Rubus rigidus agg. is an unresolved and variable species complex with at least two ploidy levels (5x, 6x). The hybrid taxon R. bergii × R. rigidus appears to be widespread and behaves as an independent apomictic complex. In addition, hybridization between R. bergii and R. pinnatus is relatively common in the contact zones between the two species. The two introductions Rubus armeniacus and R. titanus are recorded from South Africa for the first time. The invasive potential of the introduced species is regarded as low but the potential for hybridization by R. bergii seems to be high. An identification key, morphological descriptions, and notes on nomenclature, distribution and ecology are provided, and all taxa are illustrated.

Decay patterns of invasive plants and plastic trash in urban streams

Urban streams are impacted by invasion of exotic riparian plants and the accumulation of plastic trash, which alter in-stream litter subsidies, and cause changes that cascade up the aquatic food web. The impacts of these factors on urban streams is poorly understood. We compared decay rates and invertebrate colonizers of 5 litter pack types in 4 urban streams in Victoria, British Columbia, Canada: Native Red alder (Alnus rubra) and Sitka willow (Salix sitchensis), invasive English ivy (Hedera sp.), Himalayan blackberry (Rubus armeniacus) and plastic trash (i.e. Styrofoam (polystyrene (PS)), plastic bag (high-density polyethylene (HDPE)), and Mylar (polyethylene terephthalate (PET). We tested 4 hypotheses: 1) exotic ivy and blackberry leaves would decay more slowly than native leaves; 2) exotic ivy and blackberry leaves would attract fewer and less diverse stream invertebrates than native leaves; 3) plastic trash would decay more slowly than leaves; and, 4) plastic trash would attract fewer and less diverse stream invertebrates than leaves. We found no difference between the leaf litter decay rates, however plastic trash decayed more slowly than leaves. Trash decay rates were faster than reported in marine environments, suggesting that plastic trash removal should be a management priority. Stream invertebrates colonized all pack types equally. We observed significant differences in litter decay rates and invertebrate assemblage alpha and Shannon–Wiener diversities across the 4 streams - likely related to differences in stream-specific environmental attributes including flashiness, stream discharge, and biological decay. We conclude that site-specific decay forces supersede litter quality in Pacific Coast urban streams.

Habitat selection of riparian birds at restoration sites along the Trinity River, California

Riparian habitats in the western United States are imperiled, yet they support the highest bird diversity in arid regions, making them a conservation priority. Riparian restoration efforts can be enhanced by information on species response to variation in habitat features. We examined the habitat selection of four riparian birds known as management indicators at restoration and reference sites along the Trinity River, California. We compared vegetation structure and composition at nest sites, territories, and random points to quantify used versus available habitat from 2012 to 2015. Vegetation in focal species' territories differed between site types, and from available habitat, indicating nonrandom site choice. Birds selected aspects of more structurally complex habitats, such as greater canopy cover, canopy height, and tree species richness. Yellow‐breasted Chats preferred greater shrub cover, and Yellow Warblers preferred greater cover by non‐native Himalayan blackberry. Territory preferences on restoration sites were often a subset of those on reference sites. One exception was canopy height, which was taller on restoration site territories than random points for all species, suggesting that birds preferentially used patches of remnant habitat. Few variables were significant in nest site selection. Restoration plantings along the Trinity River were only 3–10 years old during this study, and have not developed many of the characteristics of mature riparian habitat preferred by birds, but may improve in habitat value over time. Understanding habitat selection is especially important in recently human‐modified environments, where indirect cues used to assess habitat quality may become disassociated from actual habitat quality, potentially creating ecological traps.

Invasive Blackberry Species in Oregon: Their Identity and Susceptibility to Rust Disease and the Implications for Biological Control

Two of the five species of European blackberry (Rubus fruticosus L. aggregate) along the West Coast of the United States are considered invasive. They are also similar in appearance. Biological control of invasive blackberry by Phragmidium violaceum, causal agent of a rust disease, had been under consideration when rust-diseased blackberry was discovered in Oregon in 2005. An investigation was initiated to determine whether this disease would be an important factor affecting population density of these blackberries. Surveys were made over a 5-yr period at more than 30 field sites in the Willamette Valley and along the Pacific coast of Oregon. Diseased and nondiseased blackberry specimens were collected for artificial greenhouse inoculations and for identification. The two blackberry species, Rubus armeniacus and R. praecox, were identified as the most invasive. They were readily distinguished morphologically on the basis of inflorescence and flower characteristics and to a certain extent by differences in primocane leaf and leaflet shape. Artificial greenhouse inoculation studies revealed that R. praecox was susceptible to the rust disease and that R. armeniacus was not. These results were confirmed during a field survey. Results of this investigation revealed that the rust disease will not be effective for biological control of R. armeniacus and other approaches to management of this particular species will be required.

Nest-site preference and reproductive performance of Song Sparrows (Melospiza melodia) in historically extant and colonist shrub species

Many studies report mixed results on the influence of invasive plants on native animals, partly due to uncertainties about habitat preference and reproductive performance in native animals before and after plant invasion. We used vegetation surveys 20 years apart and 18 years of breeding data from Song Sparrows (Melospiza melodia (A. Wilson, 1810)) to compare nest-site preference and reproductive performance during the colonization of Mandarte Island, British Columbia, by one shrub species native to the region but historically absent from the island (red elderberry, Sambucus racemosa L.) and another species that is exotic to North America (Himalayan blackberry, Rubus armeniacus Focke = Rubus bifrons Vest). Nest-site preference declined where red elderberry increased but was unrelated to change in the cover of Himalayan blackberry. Song Sparrows nested in trailing blackberry (Rubus ursinus Cham. and Schltdl.) and its exotic congener Himalayan blackberry in preference to two common shrubs native to Mandarte Island (Nootka rose, Rosa nutkana C. Presl; snowberry, Symphoricarpos albus (L.) S.F. Blake) and built just 1 of 1051 nests in red elderberry. In contrast, reproductive performance was similar in all shrub species used regularly as nest substrates. Our results show that Song Sparrow nest-site preference and reproductive performance were independent of plant species origin.