<p>Fish communities in agricultural headwater streams are known to be impacted by a variety of factors, including water chemistry, habitat modification, and hydrology. Little research has been conducted on how climate change influences these communities, yet the effects of climate on lake and river fish have been well documented. I hypothesized that fish community metrics would be reduced by the effects of climate change. I examined the effects of climate and hydrology metrics on fish communities at nine sites in the Saint Joseph River, Indiana and Michigan and at 18 sites in the Upper Big Walnut Creek, Ohio watersheds, from 2006 to 2019. Air temperature, water temperature, precipitation, water discharge, width, velocity, and depth metrics were calculated seasonally for each sampling year. Fish were examined seasonally with backpack electrofishing and seine netting and identified to species level. Principal component analyses were used to create axes which represented gradients of climate and hydrology metrics. Linear mixed effect and logistic regression modeling suggested that hydrology is a stronger predictor than climate, but that both influence fish communities. Percent Percidae, percent herbivore, and percent open substrate spawner were positively correlated with precipitation and water temperature. Presence herbivore was negatively correlated with precipitation and positively correlated with water temperature. My data only somewhat supported the hypothesis that climate would reduce fish community metrics. Gradients of hydrology were observed to be stronger predictors than gradients of climate. However, one must acknowledge relationships between climate and hydrology and the potential for climate to have indirect effects on fish communities through influences on hydrology. This study increases understanding of how fish communities in agriculturally dominated headwater streams are influenced, and emphasizes the need for further research on how these fishes will be impacted by a changing climate. </p>

When a species is introduced outside their native range, the genetic diversity of the introduced population is generally decreased due to the founder effect, and the fitness of individuals in the introduced population may decrease due to inbreeding depression. Invasive species are a paradox to this paradigm because while the initial population size of an invasive species may be small in their non-native range, the individuals are able to survive, eat, and reproduce so successfully, that they have deleterious effects on native species. One mechanism that invasive species use to overcome a lack of genetic diversity and adapt to their new environment is CpG methylation, a heritable and environmentally influenced epigenetic modification that regulates the expression of certain genes to alter phenotypes without altering an organism’s DNA sequence.Bighead and silver carps, two species of bigheaded carp native to eastern Asia, are believed to have been introduced to the United States in the 1970s. Since that time, populations of both bighead and silver carp have surged, particularly in the Mississippi River drainage, where they compete with native planktivores for food, injure boaters, and threaten the multi-million dollar fisheries industry in the Great Lakes. In this study, methylation-sensitive amplified fragment length polymorphisms (MS-AFLPs) were used to analyze the genetic and epigenetic diversity of bighead and silver carp from the Gan, Pearl, and Yangtze rivers in their native China and from the Illinois River in the United States. While the heterozygosity of silver carp in Illinois was not found to be significantly lower than that of silver carp in China, the silver carp in Illinois did show a significantly higher level of methylation compared to Chinese silver carp. There is evidence that CpG methylation may play a significant role in allowing silver carp to adapt and thrive in an introduced environment.

<p>U ovoj studiji su predstavljeni rezultati taksonomskog, fitogeografskog i ekolo&scaron;kog istraživanja urbane flore Novog Sada sa posebnim osvrtom na uče&scaron;će alohtonih vrsta, i&scaron;čezlih i ugroženih taksona i prirodne resurse lekovitog bilja. Sprovedene taksonomske analize su komparativno rađene na ukupnoj urbanoj flori (850) i flori ruderalnih stani&scaron;ta (344) Novog Sada. Zabeleženi su i&scaron;čezli i ugroženi biljni taksoni na teritoriji grada Novog Sada. Ukupno 79 vrsta se smatra da je nestalo sa područja grada Novog Sada do<br />dana&scaron;njeg period,a &scaron;to je 8,04% od ukupnog broja vrsta. Utvrđeno je&nbsp; 115 (12,85%) vrsta koje su ugrožene na području grada Novog Sada. Od ukupno 895 vrsta ruderalne flore invazivne vrste&nbsp; su zastupljene sa 74 predstavnika (8,25%). Analizom ukupne flore evidentirano je 123 lekovitih biljaka. Iz ukupne flore izdvojene su biljke sa etarskim uljem, alkaloidima, fenolima i vitaminima koje koristi zvanična medicina. Od ukupnog broja taksona, izdvojeno je 23 medonosne biljke, 25 krmnih biljaka, 60 ukrasnih vrsta, 35 industrijskih, 68 alergijskih biljaka i 7 vrsta koje vezuju tlo. Analizom odabranih biljnih organa invazivnih vrsta&nbsp; (<em>Solidago gigantea, Iva xanthifolia, Amorpha futicosa, Fallopia<br />japonica i Ailanthus altissima</em>)&nbsp; utvrđen je ukupni sadržaj fenola i flavonoida.<br />Najveći sadržaj analiziranih ukupnih sekundarnih biomolekula (fenola i flavonoida) je utvrđen u&nbsp;<em> Fallopia japonica, Ailanthus altissima&nbsp; i&nbsp; Amorpha fruticosa</em>.&nbsp; Antiradikalsko delovanje&nbsp; ispitivanih ekstrakata je utvrđeno na nivou neutralizacije reaktivnih kiseoničnih vrsta (OH, NO i DPPH radikala). Antiradikalsko delovanje na nivou neutralizacije&nbsp; OH radikala odnosno najsnažnije &bdquo;skevindžer&ldquo; delovanje ispoljeno je od strane ekstrakta lista <em>Fallopia japonica</em>&nbsp; (IC50=10,89 &mu;g/ml)&nbsp; dok je ne&scaron;to manju aktivnost pokazala&nbsp;cvast pomenute vrste (IC50=14,87 &mu;g/ml).</p> / null / <p>Results of taxonomy, phitogeogrphical and ecological analysis of ruderal flora of Novi Sad with special attention in alien species and medicinal plant as natural resorces of&nbsp; ruderal flora are presented in this Thesis. Floristic review involving, taxonomy,&nbsp; phitogeographical and ecological analysis of total (895) and ruderal flora (344) of Novi Sad. Extincted (79) and endangered (115) species were recorded in the urban flora of Novi Sad. Invasive species (74) were recorded in total flora (8,25 %).<br />Analysis&nbsp; of the total urban flora of Novi Sad as potential natural resorces recorded 123 medicinal herbs (32 alien and 91 native), 23 nectar and polen rich plants, 25 forage crops, 60 ornamental, 35 plants for industrial use, 68 allergic i 7 soil errosion control plants.<br />The analysis of sampled plant organs of invasive species (Solidago gigantea, Iva xanthifolia, Amorpha futicosa, Fallopia japonica i Ailanthus altissima) were determined total phenolic compounds and flavonoids. Antioxidant activity of plant extracts&nbsp; was determined at the level of neutralizing reactive oxygenspecies (OH,&nbsp; NO and DPPH radicals). The Content of total phenolics and flavonoids were determinated in&nbsp; Fallopia japonica, Ailanthus altissima&nbsp; and Amorpha fruticosa. The best values of OH radical&nbsp; neutralization indicated leaves of&nbsp; Fallopia japonica&nbsp; (IC50=10,89 &mu;g/ml) and flowers (IC50=14,87 &mu;g/ml).</p>

This study was stimulated by a publication of Mr Mike Bosch (Bosch 2007) that Cereus jamacaru DC (Cactaceae) used by him on his farm is effective for gastrointestinal nematode control in livestock. This plant, widely known as Queen of the night, is a serious invasive weed. We evaluated this claim in in vitro assays and in vivo experiments in sheep experimentally infected with Haemonchus contortus and Trichostrongylus colubriformis. This is the first report of such an anthelmintic trial in livestock involving C. jamacaru. The first study was to repeat the farmer’s work under strictly controlled conditions. In vivo studies were conducted to determine the possible direct anthelmintic effects of C. Jamacaru on ovine gastrointestinal nematodes. Eighteen sheep were allocated to three groups and were infected with 4000 H. Contortus and 6000 T. Colubriformis infective larvae given in 3 divided doses over a period of three days. From day 0 until day 49 of the experiment, sheep were drenched once a week with fresh blended C. jamacaru plants with the core removed at the same (32.33 g/sheep) or double the dose (64.66 g/sheep) used by Mr Bosch. No negative effects of the double dose were observed during the period of the experiment. Faeces were collected twice a week for faecal egg count. Based on the in vivo experiments, C. Jamacaru was not effective in reducing H. Contortus and T. Colubriformis in sheep to the 70% reduction levels of the control treatments considered to be a useful reduction in FEC. Nevertheless, its in vivo activity was substantial at the higher dose and reduced the FECs by 65%. To investigate the matter further some additional experiments were carried out. Specimens of C. Jamacaru were collected and dried in the shade. For the phytochemical analysis and in vitro experiments, the dried material was milled to a fine powder, it was extracted with acetone and five fractions (hexane, butanol, water, chloroform and 35% water in methanol) were obtained by solvent-solvent fractionation. The chemical composition of the fractions and crude extract was analysed by thin layer chromatography using three solvent systems of varying polarity and pH. To detect the separated compounds, vanillin-sulphuric acid-methanol was sprayed on the chromatograms and heated at 110°C for optimal colour development. The antioxidant activity in plant extracts may influence the immune systems of animals and have an indirect effect. The antioxidant activity was therefore determined. For qualitative analysis of antioxidant activity, the 2,2, diphenyl-1-picrylhydrazyl (DPPH) assay on TLC plates was used as a test for the radical scavenging ability of the compounds present in the different extracts. In the DPPH qualitative analysis of antioxidant activity there were a number of antioxidant compounds present in some of the extracts and fractions but the activity appeared to be low. This observation was confirmed in the TEAC quantitative analysis of antioxidant activity. Even the fraction with the highest activity was about 8 times less active than trolox or ascorbic acid. It therefore appears that stimulation of the immune system by antioxidant activity does not explain the results found on the farm. The antibacterial and antifungal activities were determined against 4 bacteria (Staphylococcus aureus, Enterococcus faecalis, Escherichia coli and Pseudomonas aeruginosa) and 3 fungi (Aspergillus fumigatus, Candida albicans and Cryptococcus neoformans). The minimum inhibitory concentration (MIC) values for plant extracts varied from 0.04 to 2.5 mg/ml. E. coli was the most sensitive and the fungi were in general resistant to the extract and fractions. In general the activity was not very good, especially if the dosage in an aqueous system on the farm is considered. Antimicrobial activity also does not explain the results obtained. The nematocidal activity was evaluated by an egg hatch assay and larval development viability assay (LDVA) in vitro. The acetone extract inhibited egg hatchability and killed infective larvae of H. Contortus nematodes of sheep in a concentration-dependent manner. The percentage inhibition of egg hatching of the acetone extract and the butanol, chloroform, 35% water in methanol, hexane and water solvent-solvent fractions were 100%, 100%, 94%, 91%, 9% and 16%, respectively. The percentage inhibition of larval development of the acetone extract and chloroform, 35% water in methanol, hexane and water fractions were 93%, 84%, 49%, 85%, 31%, respectively. The chloroform fraction was significantly more active than all the other fractions (p<0.05). The extracts had in vitro activity against the nematodes. The activity was however much lower than the positive control, albendazole. It is disappointing that our results do not provide an explanation for the success obtained by Mr Bosch on his farm. Even if we do not understand how it works it may be useful to prepare suitable dosages (using low level technologies adaptable to rural conditions) for use by resource-poor rural communities where C. jamacaru occurs as an invasive weed. Copyright / Dissertation (MSc)--University of Pretoria, 2010. / Paraclinical Sciences / unrestricted

<p>Aquatic macroinvertebrates of channelized headwater streams in agricultural landscapes are exposed to alterations in chemistry and physical characteristics of benthic sediments. These habitat alterations are known to influence communities of aquatic macroinvertebrates. Benthic sediments can have a wide range of impacts and influences on aquatic macroinvertebrates. I hypothesized that sediments would play a significant role in determining macroinvertebrate community structure within agriculturally dominated headwater streams. I evaluated the influences of sediment chemistry characteristics and physical characteristics on aquatic macroinvertebrate communities in Cedar Creek, Indiana and Michigan, and the Upper Big Walnut Creek, Ohio, during 2017 and 2018. Macroinvertebrates were collected twice per year using artificial substrate and leaf pack samplers and identified to the family level. Sediments were sampled two times per year and analyzed for seven physical characteristics and twenty sediment chemistry characteristics. Principle component analyses were used to create axes that are indicators of gradients of sediment chemistry and physical characteristics that occur among the samples. Macroinvertebrate community metrics used in the analyses included abundance, Shannon Diversity Index, Hilsenhoff Biotic Index scores, Invertebrate Community Index scores, percentage of collector-filters, percentage of scrapers, percentage of Chironomidae and a Berger-Parker Reciprocal Index of dominance. Linear Mixed Effect Model analyses revealed that both sediment chemistry and physical characteristics influence macroinvertebrate community metrics. Aquatic macroinvertebrate abundance was negatively correlated with increasing concentrations of simazine and decreasing concentrations of calcium. Percentages of Chironomidae were positively correlated with increasing percentages of sand and decreasing percentages of clay and decreasing diversity of sediment particle sizes. My data supported the hypothesis that benthic sediments play an important role in determining aquatic macroinvertebrate community structure in headwater streams of agriculturally dominated landscapes. Gradients of chemical characteristics containing simazine and calcium were observed to be negatively correlated with macroinvertebrate abundance. Gradients of physical characteristics including percentages of sand and clay along with the diversity of particle sizes were observed to be positively correlated with percentage of chironomids. My research increases the knowledge that benthic sediments, chemically and physically, can lead to alterations in aquatic macroinvertebrate communities within Midwestern headwater streams. </p>

No description available.

Alien invasive plants are of concern in the world because of their potential to spread into the natural environment. Invasion patterns observed in plant species can be attributed among other things to favourable environmental conditions. Understanding invasion dynamics of alien invasive plants can help in timely intervention initiatives. In Mpumalanga, Lilium formosanum (Liliaceae) appears to be an emerging plant invader and is spreading in the natural environment. The study investigated the invasion extent and predictor variables which could explain abundance patterns of L. formosanum in the invasive range in Mpumalanga province in South Africa and further predict regions of the world that could be climatically suitable. Lilium formosanum was surveyed along 11 major routes leading into the towns of Sabie and Graskop in Mpumalanga from a slow moving vehicle. A total of 241 kilometres was surveyed. Lilium formosanum was found to be invasive from the towns of Sabie and Graskop. Climatically suitable areas were predicted using DIVA-GIS and climate data was obtained from WORLDCLIM database while occurrence records were obtained from the Southern African Plant Invaders Atlas, Australia’s virtual herbarium and the Global Biodiversity Information Facility. In conclusion, distance, altitude and route were found to have an influence on the abundance of L. formosanum in Mpumalanga Province. Climatically suitable areas included the eastern coastal belt, northern provinces and the interior parts of South Africa including major parts of Limpopo and Mpumalanga. / Dissertation (MSc)--University of Pretoria, 2014. / Plant Production and Soil Science / MSc / Unrestricted

No description available.

Premise: Invasive plant species can integrate into native plant–pollinator communities, but the underlying mechanisms are poorly understood. Competitive interactions between invasive and native plants via heterospecific pollen (HP) and differential invasive HP effects depending on HP arrival time to the stigma may mediate invasion success, but these have been little studied. Methods: We evaluated patterns and effects of HP receipt on pollen tube growth in two native and one invasive species in the field. We also used hand-pollination experiments to evaluate the effect of invasive HP pollen and its arrival time on native reproductive success. Results: Native species receive smaller and less-diverse HP loads (5–7 species) compared to invasive species (10 species). The load size of HP had a negative effect on the proportion of pollen tubes in both native species but not in the invasive, suggesting higher HP tolerance in the latter. Invasive HP arrival time differentially affected pollen tube success in native species. Conclusions: Our results highlight the need to study reciprocal HP effects between invasive and native species and the factors that determine differential responses to HP receipt to fully understand the mechanisms facilitating invasive species integration into native plant–pollinator communities.

The cold water of Antarctica has a unique endemic fauna, where durophagous predators are rare or absent. Due to climate change the water is heating up and the predators have begun to return to the Southern Ocean, which could bring a lot of changes to the food web. There is a high risk it will lead to losses in the unique marine fauna of Antarctica. The aim of this study is therefore to examine the potential effect these invasive species has on the food web structure in the Weddell Sea. To study this, several general network metrics were used (connectance, number of interactions, vulnerability and generality, trait distributions), as well as a number of centrality metrics (betweenness, closeness, PageRank). The analyses showed that none of the invasive species become important in the Weddell Sea food web. Nor do they significantly change the food web structure in any way which impact the importance of the native species. Their great opportunism regarding their prey species, and thereby their connectedness and thus their position in the network, are probably the main reason why theses invasive species did not become important in this food web. The lack of changes in the food web structure due to the presence of these invasive species are probably also a result of not including factors such as abundances and network dynamics in the analyses, which seem to be the driving forces when it comes to changes in food web structure caused by invasion of species.