Carduus Nutans Research Articles

Working smarter, not harder: objective-dependent management of an invasive thistle, Carduus nutans

AbstractMany invasive species managers state that their objective is to “control” an invader. However, the appropriate choice of a management option requires a more explicit statement of management objectives, in terms of both the relevant time horizon and spatial scale. Using data from a 2-yr mowing experiment, we show that the most effective management strategy for controlling an invasive thistle depends fundamentally on the management goals. We integrate field data from a two-cohort experiment with modeling to assess 14 mowing treatments (differing in intensity, frequency, and timing, and thus also in their required logistical effort) based on their effectiveness in (1) reducing population density of the existing cohort, (2) decreasing projected long-term population growth, and (3) limiting projected population spread of an invasive thistle, musk thistle (Carduus nutans L.). The treatment with high intensity and a single late mow caused the largest reduction in plant survival (and density of existing adult plants); the treatment with high intensity and an early mow in addition to a late mow was most effective at reducing population growth rate and population spread. Against expectation and conventional wisdom, the most frequent mowing treatment did not provide the most effective management outcome for any stated objective. This study highlights the necessity of clearly defined management aims; the term “control” is too vague to be truly useful. The results also provide important insights for the management of this invasive species.

Three prospective agents instead of one? Cryptic diversity of the biological control agent Psylliodes chalcomera

The flea beetle, Psylliodes chalcomera, was previously permitted as a biological control agent of Carduus nutans (musk thistle) in the USA. However, during subsequent exploration for prospective biological control agents of Centaurea solstitialis (yellow starthistle), we observed individuals attacking this plant in southern Russia. We also observed this insect on Onopordum spp. (Scotch thistle), which raised the question whether this beetle is polyphagous, or whether it is comprised of biotypes, host races or cryptic species that are specialized on different host plants. We analyzed a fragment of the cox1 mitochondrial gene of adult and larval specimens collected from these three plants in Bulgaria, Italy, Russia and Turkey to study the population structure of this beetle. The results indicate at least three different groups: 1) associated with C. solstitialis in Bulgaria, Russia and Turkey, 2) associated with Onopordum spp. in Bulgaria, Russia and Turkey, and 3) associated with Carduus spp., Onopordum spp., and possibly C. solstitialis, in Bulgaria, Italy, Russia and Turkey. Adult specimens indicated a fourth group associated with Onopordum spp. and C. solstitialis in Turkey, but we did not have any larval specimens to confirm the host plant of this group. Our results suggest that three of these biotypes could be interesting to evaluate as prospective candidates for classical biological control of these three weed targets.

Analysis of phenolic compounds and antioxidant activity of methanolic extracts from inflorescences of Carduus sp

In the present study, the phenolic compounds in 70% (v/v) methanol extracts from the inflorescences of Carduus carlinoides Gouan, Carduus nigrescens Vill, Carduus defloratus L., Carduus nutans L., and Carduus crispus Gouan were identified. The extracts were tested by the RP-HPLC and HPLC/ESI-QTOF/MS methods. Flavonoids and phenolic acids were extracted from the inflorescences by ASE. HPLC profiles (fingerprints) of methanolic Carduus sp. extract were correlated with flavonoid and phenolic acid content by using chemometric methods. The obtained results revealed that various species showed characteristic profiles of phenolic acids and flavonoids. These compounds included nine flavonoids (isorhamnetin-3-glucoside, kaempferol-3-rhamnoglucoside, luteolin-7-glucoside, luteolin-7-glucuronide, apigenin-7-glucoside, kaempferol-3-rutinoside, kaempferol-3-rhamnoglucoside, apigenin, and luteolin) and five phenolic acids (neochlorogenic, chlorogenic, caffeic, protocatechuic, and p-hydroxybenzoic acids). Also the evaluation of antioxidant activity of 70% (v/v) methanolic extracts, which was expressed both as a percentage of DPPH radical inhibition and EC50 values (mg/mL). The EC50 values for all obtained extracts were as follows: C. nutans (EC50 = 0.46 mg/mL), C. carlinoides (EC50 = 0.60 mg/mL), C. crispus (EC50 = 0.70 mg/mL), C. nigrescens (EC50 = 0.78 mg/mL), and C. nigrescens (EC50 = 0.80 mg/mL). Chemometric analysis of the RP-HPLC chromatograms allowed to extract four independent trends in the content of the identified components. The most identical extracts came from two species: C. nigrescens and C. deccusatus.

СОРНЯКИ - ВОЗМОЖНЫЕ РЕЗЕРВАТОРЫ ПАТОГЕНОВ ПОДСОЛНЕЧНИКА

The article presents the results of a survey of wild and weed plants in the Tambov region, many of which until recently were considered ruderal (garbage), growing only in the wasteland and away from sunflower crops, and do not affect the damage to the culture of diseases. It was found that most of the affected grass samples collected in sunflower crops, along the edges of the fields, along the roadsides, along forest belts, reservoirs, on vacant lots and other places of their habitat, belong to the family of Asteraceae. This is yarrow, wormwood, sow Thistle, burdock small, Carduus nutans, common chicory, Thistle field collagen durnishnika, jastrebinka umbrella, common tansy, common cocklebur and amaranth thrown back from the Amaranth family (Amaranthaceae). Botanical features of these herbs are briefly given. Studied and described the symptoms of their leaves and stems. From the fragments of the affected samples, pathogens of diseases common to these herbs and cultivated sunflower were isolated. Isolation of pathogens from the affected organs was carried out in the laboratory according to the generally accepted methods in Mycology and Phytopathology. Their species composition and taxonomic position are established. It was found that the most common pathogen was sunflower Phomopsis - Phomopsis/Diaporthe helianthi Munt. - Cvet. et al. It is noted that the symptoms of Phomopsis, fusariosis, downy mildew, Septoria, ascochitosis and spotting are similar to those on cultivated sunflower. The pathogenic properties of the isolated fungi were determined in laboratory conditions, in accordance with the Koch triad. As a result of artificial infection of seeds and five-day sunflower seedlings with isolates of phytopathogenic fungi isolated from these herbs, their ability to cause infection of various organs of culture has been established. Re-isolation of fungi in all cases showed their complete identity with isolates isolated from natural material. This circumstance allows to draw a conclusion about the possibility of the described herbs to be potential reserves of pathogens for cultivated sunflower.

Exploring population responses to environmental change when there is never enough data: a factor analytic approach

Abstract Temporal variability in the environment drives variation in vital rates, with consequences for population dynamics and life‐history evolution. Integral projection models (IPMs) are data‐driven structured population models widely used to study population dynamics and life‐history evolution in temporally variable environments. However, many datasets have insufficient temporal replication for the environmental drivers of vital rates to be identified with confidence, limiting their use for evaluating population level responses to environmental change. Parameter selection, where the kernel is constructed at each time step by randomly selecting the time‐varying parameters from their joint probability distribution, is one approach to including stochasticity in IPMs. We consider a factor analytic (FA) approach for modelling the covariance matrix of time‐varying parameters, whereby latent variable(s) describe the covariance among vital rate parameters. This decreases the number of parameters to estimate and, where the covariance is positive, the latent variable can be interpreted as a measure of environmental quality. We demonstrate this using simulation studies and two case studies. The simulation studies suggest the FA approach provides similarly accurate estimates of stochastic population growth rate to estimating an unstructured covariance matrix. We demonstrate how the latent parameter can be perturbed to show how selection on reproductive delays in the monocarp Carduus nutans changes under different environmental conditions. We develop a demographic model of the fire dependent herb Eryngium cuneifolium to show how a putative driver of the variation in environmental quality can be incorporated with the addition of a single parameter. Using perturbation analyses we determine optimal management strategies for this species. This approach estimates fewer parameters than previous approaches and allows novel eco‐evolutionary insights. Predictions on population dynamics and life‐history evolution under different environmental conditions can be made without necessarily identifying causal factors. Putative environmental drivers can be incorporated with relatively few parameters, allowing for predictions on how populations will respond to changes in the environment.

Bioactive potential of Indian stinging plants leaf extract against pathogenic fungi.

Background & methods We investigated the in vitro antioxidant and antifungal activity by agar disc diffusion assay of leaf extract of some stinging plants namely, Urtica dioica L., Tragia involucrate L., Carduus nutans L. and Mucuna pruriens (L.) DC., against pathogenic fungi causing infections/diseases. Results M. pruriens (Disc 4), T. involucrate (Disc 2), U. dioica (Disc 1) showed significant antifungal activity against all tested pathogens, while C. nutans (Disc 3) showed intermediate activity against only Chaetomium globosum (Cg). The leaf extract of M. Pruriens showed maximum total phenol content (~1004 µg g-1 dry wt) followed by T. involucrate, C. nutans and U. dioica. However, the ascorbate was observed highest in T. involucrate (~10.3 µg g-1 dry wt) followed by M. pruriens (~9.2 µg g-1 dry wt) but the difference was not significant (p ≤ 0.05). Likewise, M. pruriens showed maximum anthocyanin content (~0.3 µg g-1 dry wt). The activity of antioxidant enzymes revealed that M. Pruriens showed maximum ascorbate peroxidase (APX) activity, while the highest guaiacol peroxidase (GPX) and catalase (CAT) activities were observed in C. nutans and U. dioica, respectively. Conclusions M. Pruriens showed potential in vitro antioxidant and antifungal activity against studied pathogens that may be used for ethno-pharmacological uses.

Biological Control of Musk Thistle (Asteraceae) by the WeevilRhinocyllus conicus(Coleoptera: Curculionidae) and its Establishment on Nontarget Thistles in Georgia, USA1

Abstract The weevil Rhinocyllus conicus Froelich was introduced in Georgia, USA as a biological control agent of musk thistle, Carduus nutans L. (Asteraceae) in 1991. Musk thistle populations and R. conicus infestations were monitored over 10 yr at four sites in central Georgia. Musk thistle populations declined substantially as R. conicus populations increased at all sites, but thistle infestations remained problematic at some sites. A laboratory cage study found that R. conicus would lay eggs on flower buds of yellow thistle, Cirsium horridulum Michaux, bull thistle Cirsium vulgare (Savi) Tenore, and blessed milkthistle, Silybum marianum (L.) Gaertner in no-choice and choice tests with and without Ca. nutans. Carduus nutans was preferred over the other thistle species, but the other thistle species were acceptable for oviposition by R. conicus. One or more mixed field infestations of musk thistle and yellow, bull, or blessed milkthistles were sampled for R. conicus infestation. Rhinocyllus conicus was n...

Phytoremediation of Cadmium by Native Plants Grown on Mining Soil.

The Gümüsköy mining area is located about 25km west of Kutahya and is the largest silver deposit in Turkey. The present study investigated translocation and accumulation of cadmium (Cd) from the soil into 11 native plants. Plant and soil samples were collected from the field, and Cd concentrations were analyzed by inductively coupled plasma mass spectroscopy. Mean Cd values in the soil, root, and shoot of native plants in the study area were 82.8 ± 5, 55.4 ± 6, and 43.5 ± 4mg kg- 1, respectively. Plants were separated into several groups according to the enrichment coefficients for shoot and root values of plants. These groups showed Carduus nutans and Phlomis could be potentially bioaccumulator plants useful for phytoremediation of mining soils contaminated by Cd.

Genetic diversity of Bulgarian representatives of genus Carduus L. (Asteraceae) as revealed by variability in sequences of internal transcribed spacers region

ABSTRACTThe biodiversity of genus Carduus in Bulgaria is grossly under-studied with modern methods, which leads to unclear status of species and hampers the assessment of their habitats and conservation status. In this study, we used the variability of internal transcribed spacers (ITS) to investigate the biodiversity of Carduus species collected from different floristic regions of Bulgaria. Thirty-three samples were processed. Among the studied species, C. acanthoides exhibited the highest ITS variability (eight single nucleotide polymorphisms were found). High ITS variability was also found in C. crispus and C. hamulosus, demonstrating that some of the local Carduus species possesses unique genetic diversity, which can serve as source for future divergence of new forms and subspecies. For each species, unique nucleotides suitable as molecular taxonomy markers were identified. However, C. nutans and C. thoermeri displayed completely identical ITS sequences, which is in agreement with all ITS sequences of these species collected elsewhere in the world and deposited in the NCBI database. After careful analyses of both molecular and morphological data, we propose to restore C. nutans and C. thoermeri as one species with two subspecies. Namely, Carduus nutans subsp. nutans and Carduus nutans subsp. thoermeri. We recommend diameter of capitulum, length of peduncle, width of peduncle and width of bract as diagnostic features of taxonomic significance for distinguishing the two subspecies.

Climate Dynamics, Invader Fitness, and Ecosystem Resistance in an Invasion-Factor Framework

As researchers and land managers increasingly seek to understand plant invasions and the external (climate) and internal (plant genetics) conditions that govern the process, new insight is helping to answer the elusive question of what makes some invasions successful and others not. Plant invasion success or failure is based on a combination of evolutionary and ecological processes. Abiotic (e.g., climate) and biotic (e.g., plant competition) conditions in the environment and plant genetics (e.g., fitness) combine in either decreasing or increasing invasion, yet it has proven challenging to know exactly which of these conditions leads to success for a given species, even when a wealth of empirical data is available. Further, current regional distribution models for invasive plant species rarely consider biotic and fitness interactions, instead focusing primarily on abiotic conditions. The crucial role of all three factors (climate dynamics, invader fitness, and ecosystem resistance) must not be ignored. Here we construct a three-factor invasion framework from which we develop conceptual models using empirical studies for yellow starthistle, nonnative common reed, and musk thistle, three dissimilar but commonly occurring invasive plant species in North America. We identify how components of the invasion process—rapid population increase, established local dominance, and rapid range expansion—are influenced by ecosystem resistance, invader fitness, and/or climate dynamics, a set of broadly defined factors for each of the three invasive plant species. Our framework can be used to (1) establish research priorities, (2) address gaps in theoretical understanding, and (3) identify invasion process components that can be targeted to improve management. Building on previous models, our unifying framework, which can be used for assessing any invasive plant species having sufficient empirical data, simultaneously shows the influence of ecosystem resistance, invader fitness, and climate dynamics factors on the invasion process.

Carduus nutans L and the Effect on the Heavy Metals and Microenvironment Biota

The aim of the study was to identify the effect of Carduus nutans L on the heavy metals and microenvironment biota. Ten plants of Carduus nutans L were collected togheter with the rhizosphere soil and as reference the soil was collectued from an abandonated pasture where no vegetation was growing. The metal concentrations in the filtrate were determined by flame atomic absorption spectrophotometry and the total number of bacteria and actinomycetes from the average soil samples was established. Based on the mathematical models we managed to identify the effects of the heavy metals present in the Carduus nutans L rhizosphere soil samples on the development and presence of bacteria and actinomycetes colonies. We can state that iron and manganese influence the CFU of bacteria and actinomycetes and these in their turn have an impact on the zinc concentration in soil which will influence total chromium content and copper concentrations.

Characterization of four wild edible Carduus species from the Mediterranean region via phytochemical and biomolecular analyses

Carduus species (Compositae) are widely distributed in the Mediterranean area, and traditionally used for both food and medicinal purposes.The hydroalcoholic extracts of four wild edible Carduus species collected in Sardinia (Carduus argyroa Biv., Carduus nutans subsp. macrocephalus (Desf.) Nyman, Carduus pycnocephalus L., Carduus cephalanthus Viv.) were analyzed and characterized by HPLC-PDA-MS/MS and PCR-RFLP of the nrDNA internal transcribed spacer (ITS).Flavonoids and caffeoylquinic acid derivatives were the predominant classes of secondary metabolites characterizing the extracts. The ITS region was sequenced in parallel, and a PCR-RFLP method was applied with three selective restriction enzymes. Statistical analyses, on both chemical and biomolecular results, revealed that individuals clustered according to their taxonomic classification.The combination of the two techniques discriminates the four species within the genus, giving further information on these little-investigated plants, traditionally used in the Mediterranean area and in Sardinia.

Preemergence Control of Nine Invasive Weeds with Aminocyclopyrachlor, Aminopyralid, and Indaziflam

There are an estimated 400 million hectares of non-cropland in the United States primarily designated as rangeland and pastureland, and there are more than 300 invasive weeds found on these sites, causing an estimated annual loss of $5 billion. Among the most invasive and problematic weeds are Dalmatian toadflax, diffuse knapweed, downy brome, and musk thistle. Currently, herbicides are the most common management strategy for broadleaf weeds and invasive winter annual grasses. Indaziflam, a new herbicide for invasive plant management in non-crop areas, is a cellulose-biosynthesis inhibitor capable of providing residual invasive winter annual grass control up to 3 yr after treatment (YAT). A field experiment was conducted to determine whether residual Dalmatian toadflax and downy brome control by aminocyclopyrachlor, imazapic, and picloram could be extended by tank mixing these herbicides with indaziflam. Indaziflam tank mixed with aminocyclopyrachlor, imazapic, and picloram provided increased Dalmatian toadflax (84% to 91%) and downy brome (89% to 94%) control 4 YAT, compared with treatments excluding indaziflam. Treatments without indaziflam controlled 50% to 68% of Dalmatian toadflax and <25% downy brome 4 YAT. Based on these results, a greenhouse dose–response experiment was conducted with aminocyclopyrachlor, aminopyralid, and indaziflam to compare preemergence control of nine common non-crop weeds. Averaged across species, aminocyclopyrachlor and aminopyralid GR50values (herbicide concentration resulting in 50% reduction in plant biomass) were 29 and 52 times higher compared with indaziflam, respectively. These data suggest that indaziflam could be used for residual control of non-crop weeds as a tank-mix partner with other foliar-applied broadleaf herbicides.

Individually mark–mass release–resight study elucidates effects of patch characteristics and distance on host patch location by an insect herbivore

1. How organisms locate their hosts is of fundamental importance in a variety of basic and applied ecological fields, including population dynamics, invasive species management and biological control. However, tracking movement of small organisms, such as insects, poses significant logistical challenges.2. Mass‐release and individual–mark–recapture techniques were combined in an individually mark–mass release–resight (IMMRR) approach to track the movement of over 2000 adult insects in an economically important plant–herbivore system. Despite its widespread use for the biological control of the invasive thistle Carduus nutans, the host‐finding behaviour of the thistle head weevil Rhinocyllus conicus has not previously been studied. Insects were released at different distances from a mosaic of artificially created host patches with different areas and number of plants to assess the ecological determinants of patch finding.3. The study was able to characterize the within‐season dispersal abilities and between‐patch movement patterns of R. conicus. Weevils found host plant patches over 900 m away. Large patches, with tall plants, situated close to the nearest release point had the highest first R. conicus resights. Patch area and plant density had no effect on the number of weevils resighted per plant; however, R. conicus individuals were more likely to disperse out of small patches and into large patches.4. By understanding how R. conicus locates host patches of C. nutans, management activities for the control of this invasive thistle can be better informed. A deeper mechanistic understanding of host location will also improve prediction of coupled plant–herbivore spatial dynamics in general.

Phytochemical Analysis of Indian Stinging Plants: An Initiative Towards Development of Future Novel Biothreat Agents for Self-defence

This manuscript discusses the phytochemical analysis of stinging plants and/or their biological toxins as novel future bio-threat agents that may be used for self-defence purpose. The selected stinging plants namely, Urtica dioica L., Tragia involucrata L., Carduus nutans L. and Mucuna pruriens (L.) DC, have dual role as nutraceutical and ethno-pharmacological uses apart from their less-explored stinging property. The phytochemical analyses of their secondary metabolites including phenolics, terpene and N-containing compounds were measured. M. pruriens showed maximum total phenolic content (~1004 µg g−1 dry wt) followed by those of T. involucrata, C. nutans and U. dioica. Similarly, the flavonoid content was also found highest (~500 µg of QE g−1 dry wt) in M. pruriens. However, the tannin content was maximum (~654 µg g−1 dry wt) in T. involucrata followed by M. pruriens. Likewise, the terpenoid content was maximum (~350 µg of Lil g−1 dry wt) in U. dioica followed by M. pruriens, T. involucrata and C. nutans. FRSA was maximum (~31%) in M. pruriens. However, the oil content was highest in T. involucrata followed by U. dioica, M. pruriens and C. nutans. In addition, the alkaloid content was maximum (~523 µg of AE g−1 dry wt) in M. pruriens. These findings clearly suggest that M. pruriens has higher potential for harvesting of toxic compounds as compared to other studied plants for the formulation of novel future bio-threat agents for self-defence. However, detailed work is required for identification of the precise stinging chemical components.

Seed release in a changing climate: initiation of movement increases spread of an invasive species under simulated climate warming

AbstractAimReliable estimates of how species will move under future climatic conditions are lacking, and the ability of species to track suitable habitat under climate change is strongly predicated on dispersal. In wind‐dispersed plants, initiation of movement by maternal seed release characteristics can affect the ultimate shape of the dispersal kernel. If seed dispersal traits respond to altered local abiotic conditions induced by climate change during development, the effects could have major impacts on projections of future population spread.LocationCentral Pennsylvania, USA.MethodsTo quantify how seed release characteristics might be affected by climate change, we experimentally manipulated temperature in a field study of the wind‐dispersed, invasive plant Carduus nutans (Asteraceae). We quantified seed release in a series of trials conducted in a full‐size experimental wind tunnel, and we examined the effect of the probability of seed release on the projected population spread rate (c*).ResultsExperimental warming over the growing season significantly increased the probability of seed release in wind tunnel trials by 7%. When these data were incorporated into matrix integro‐differential equation models of population spread for this species, the measured increase in seed release, combined with previously reported increases in plant height, resulted in a projected increase in the population spread rate of C. nutans of 38% per year due to increased temperature.Main conclusionsIgnoring altered seed release dynamics significantly underestimates the increase in potential spread rate by 11%. This increase could allow this species to reach suitable habitat more quickly than expected from existing models of population spread, and could require management timing to shift in the future. More generally, our results suggest that models of future distributions of other wind‐dispersed species that do not include information about species' dispersal responses to climate may incur significant errors and could result in poorly applied management or inadequate spatial risk assessment.

Calcium oxalate crystals in some species of the Tribe Cardueae (Asteraceae)

In this study, calcium oxalate (CaOx) crystals in the tissues and organs of 18 species that belong to tribe Cardueae (Asteraceae), Arctium minus, Silybum marianum, Cirsium vulgare, Cirsium creticum, Cirsium arvense, Carduus nutans, Carduus candicans, Carduus pycnocephalus, Tyrimnus leucographus, Jurinea consanguinea, Centaurea diffusa, Centaurea solstitialis, Centaurea iberica, Centaurea salonitana, Centaurea cyanus, Carthamus lanatus, Carthamus dentatus and Xeranthemum annuum , were investigated, and their morphologies and distribution were determined using a light microscope. Two morphological types of crystals, styloids and prismatics, were the most found crystals in the species examined. Raphides were only observed in the stem cortex and pith parenchyma cells of Silybum marianum, while druses were only viewed in the stem pith cells of Carduus pycnocephalus. Styloids were observed (if present) in the leaf, corolla, anther, filament, and style tissues. Prismatic crystals were seen almost in all the ovaries of the species investigated, except for Xeranthemum annuum. Prismatics, styloids, raphides, and druses were present in the stems of the species. It is considered that crystal formation within the cell is under genetic control. Thus the type, and presence or absence of crystals may be represented as a taxonomic character. In conclusion, it is suggested that the shape and location of CaOx crystals in the Cardueae constitute a diagnostic character and they may have taxonomic significance in this tribe.

Can Thistles (Carduus nutans L.) be Considered as Silage with Some Additives

The aim of this study was to assess nutritional characteristics of thistle silages with additives. Thistle plant material collected around the faculty of Agriculture, Ataturk University in 2010 were ensiled without and with 1% salt, 5% barley meal, 1% molasses and 10% wheat straw in triplicates. Dry matter, crude protein contents and pH values varied from 51.77 to 60.16%, 8.54 to 11.84%, and 4.69 to 4.92, respectively. The fleigh score was determined as very good, although the physical grades of silages were medium. Acid detergent fiber and neutral detergent fiber contents and relative roughage value varied from 39.00 to 47.8%, 57.23 to 65.32% and 73.57 to 94.31, respectively. The obtained silages was found rich in term of macro and micro minerals. The effects of additives on nutrient content and physical characteristics were variable. In conclusion, thistle silage can be used in feeding dry cows and young ruminants due to its protein, fiber, and mineral contents. Further harvesting stage and digestibility studies are needed to determine proper additive to improve nutritional characteristics. Keywords: molasses, silage, fleigh score Bazi Katki Maddelerinin Ilavesi ile Deve Dikeni Bitkisi ( Carduus nutans L.) Silaj Olarak Degerlendirilebilir mi? OZET: Bu calismanin amaci katki maddeleri ile birlikte deve dikeni bitkisinin beslenme ozelliklerinin belirlenmesidir. Bitki materyali 2010 yilinda Ataturk Universitesi Ziraat Fakultesi arazisinden toplanmis, 3 tekerrurlu olarak kontrol, %1 tuz, %5 arpa kirmasi, %1 melas ve %10 bugday samani kullanilmistir. Kuru madde, ham protein icerikleri ve pH degerleri sirasiyla % 51.77-60.16, % 8.54-11.84 ve 4.69-4.92 arasinda degismistir. Silajlarin fiziksel dereceleri orta duzeyde olmasina ragmen Fleigh puani cok iyi olarak tespit edilmistir. Asit cozuculerde cozunmeyen lif, Notr cozuculerde cozunmeyen lif ve nispi yem degerleri sirasiyla % 39.00-47.82, %57.23-65.32 ve %73.57-94.31 arasinda degismistir. Elde edilen silaj makro ve mikro elementler bakimindan zengindi Besin icerikleri ve fiziksel ozellikler uzerine katki maddelerinin etkileri degiskenlik gostermistir. Deve dikeni silaji besin, lif ve protein iceriklerinden dolayi sigirlarin ve genc gevis getiren hayvanlar icin besin maddesi olarak kullanilabilecegi tespit edilmistir. Bununla birlikte hasat zamani, besleme degeri ve katki maddeleri uzerine ileri calismalara ihtiyac vardir. Anahtar kelimeler: melas, silaj, fleigh puani

Plant community associations of two invasive thistles.

In order to combat the growing problems associated with biological invasions, many researchers have focused on identifying which communities are most vulnerable to invasion by exotic species. However, once established, invasive species can significantly change the composition of the communities that they invade. The first step to disentangling the direction of causality is to discern whether a relationship with other vegetation exists at all. Carduus nutans and C. acanthoides are similar invasive thistles, which have caused substantial economic damage worldwide. We assessed the associations between the thistles and the standing flora in four sites in central Pennsylvania in which they co-occur. After sampling nearly 2000 plots of 1 m(2), we used partial Mantel tests to assess the differences in vegetation between thistle and non-thistle plots after accounting for location, and non-metric multidimensional scaling to visualize differences among plots and sites. We found significant differences in community composition in plots with and without Carduus thistles. The non-native species Sisymbrium officinale and Coronilla varia were consistently associated with the presence of Carduus thistles. Several species were associated with areas that were free of Carduus thistles, including an important non-native pasture species (Trifolium repens). We found no evidence for differences in composition between plots with C. nutans versus C. acanthoides, suggesting that they have similar associations with the vegetation community. We conclude that even at the within-field scale, areas invaded by Carduus thistles have different vegetation associations than uninvaded areas, allowing us to target future research about the role of vegetation structure in resisting and responding to invasion.

Post‐dispersal seed removal of Carduus nutans and C. acanthoides by insects and small mammals

AbstractThe journey of wind‐dispersed seeds does not necessarily end when they land. Secondary dispersal and/or predation can positively or negatively affect the spread of invasive plants. Here we studied post‐dispersal seed removal of nodding and plumeless thistle (Carduus nutans and C. acanthoides) in part of their invaded range in Pennsylvania, USA. The relative impact of small mammals and insects was determined using exclusion treatments in the field. In cages that allowed insect access, 88 % of the seeds were removed after 1 day, and 99.9 % were removed after the 6‐day trial. When insects were excluded, the removal rate was significantly lower (18 % after 1 day, 40 % after 6 days). The seed removal rates provide an upper limit to the seed predation rate, with the understanding that it is also possible for seed removal to be an important secondary dispersal mechanism. We discuss a combined empirical‐theoretical approach to evaluate the impact of these alternative seed fates on the spread and management of these thistles.