Las hormigas invasoras desplazan a las especies de hormigas nativas y otros artrópodos. Como consecuencia, las interacciones biológicas del sistema invadido y los servicios ecológicos prestados por las especies nativas son modificados. El objetivo de este trabajo fue investigar los efectos de la hormiga invasora Lasius neglectus sobre algunos de los componentes superficiales y subsuperficiales de un encinar urbano y compararlos con los efectos de las hormigas nativas, en particular con Lasius grandis. Lasius neglectus visita principalmente árboles aislados donde permanece más meses atendiendo áfidos. Por el contrario, las hormigas nativas no visitaron los árboles según su ubicación (aislado, borde o centro del bosque). Excepto en el caso de la hormiga nativa Lasius grandis, que permaneció más tiempo en los árboles aislados cuando Lasius neglectus no estaba presente en el fragmento. La riqueza de especies nativas de hormigas y su visita a los árboles fue menor en fragmentos de bosque con Lasius neglectus. Crematogaster scutellaris, Temnothorax lichtensteini y Lasius grandis lograron coexistir con la hormiga invasora. La estructura de la comunidad de hormigas nativas en fragmentos con o sin Lasius neglectus mostró un patrón aleatorio. Entre Mayo y Octubre, en las encinas se encontraron dos especies de áfidos, Hoplocallis picta, ocasionalmente atendido por las hormigas, y Lachnus roborisun un mirmecófilo obligado. En encinas visitadas por la hormiga invasora, se observó que la abundancia de Lachnus roboris tendió a duplicarse, como así también su producción de melaza, porcentaje de colonias atendidas comparado con los resultados obtenidos en encinas visitadas por la hormiga nativa Lasius grandis. Consecuentemente, durante el periodo estudiado la hormiga invasora duplicó su colecta de melaza por encina respecto de la hormiga nativa. Las colonias de Lachnus roboris se ubicaron principalmente sobre las bellotas. Sin embargo, no se detectó ningún efecto en la producción o calidad de bellotas y en la emergencia o calidad de las plántulas. Ambas especies de hormigas capturaron principalmente Pscópteros y Hoplocallis picta como fuente de proteínas. El porcentaje de obreras que llevaba insectos o trozos de artrópodos entre sus mandíbulas fue superior para Lasius grandis. La comunidad de artrópodos y el nivel de herbivoría no fueron modificados por la presencia de una u otra especie de hormiga. Sin embargo, en las encinas visitadas por Lasius neglectus las arañas, los curculiónidos y los áfidos tendieron a incrementar su abundancia mientras que las larvas de coccinélidos (predadores de áfidos) disminuyeron marcadamente. La melaza que no es recogida por las hormigas puede incorporarse al suelo disuelta en el agua de trascolación de la copa como carbono orgánico disuelto (COD). La colecta de melaza de Lasius neglectus disminuyó el COD disuelto en el agua de trascolación de las encinas lo cual indicaría una interrupción del flujo de materia y energía entre la copa de las encinas y el suelo aledaño. En relación a los efectos subsuperficiales se observó que el contenido de nutrientes en el suelo aledaño a las encinas visitas por Lasius neglectus fue mayor respecto del encontrado en encinas visitadas por hormigas nativas. Asimismo, la comunidad de microorganismos se diferenció según la presencia de hormigas nativas o de la invasora; tendiendo la biomasa microbiana del suelo a ser mayor en el caso de la presencia de Lasius neglectus. Según la localidad estudiada, la calidad de la hojarasca producida fue menor en los árboles visitados por Lasius neglectus. Sin embargo, la descomposición de la hojarasca de encina no fue modificada por la presencia de la hormiga invasora. Se concluye que la presencia de Lasius neglectus modifica aquellos componentes, superficiales y subsuperficiales, del sistema de la encina que están directa o indirectamente relacionados con la colecta de melaza. / Invasive ants displace native ant species and other arthropods. As a consequence, at the invaded system biological interactions and ecological services provided by native ant species are modified. The aim of this study was to investigate some of the above-belowground effects of the invasive ant Lasius neglectus in an urban holm oak forest and to compare these effects with those of native ant species, in particular related to Lasius grandis.Lasius neglectus mainly visited isolated trees where workers remained more months tending aphids and other insects. On the contrary, native ant tree visitation was not related to tree position in the fragments (isolated, edges or core trees). The only exception was the native ant Lasius grandis which remained more months at isolated trees in fragments where Lasius neglectus was not present. Native ant species richness and its tree visitation were lower at fragments where Lasius neglectus was present. Crematogaster scutellaris, Temnothorax lichtensteini y Lasius grandis were able to coexist with the invasive ant specie. Community structure of native ants did not differ from a random pattern with or without Lasius neglectus.Some effects of the ant presence were investigated in detail at the holm oak (Quercus ilex) since this tree was the most abundant at the studied forest fragments. Between May and October, two aphid species were found feeding at holm oak canopy: Hoplocallis picta, which was occasionally tended and Lachnus roboris which was the main tended species. At holm oaks visited by the invasive ant, the abundance of Lachnus roboris tended to increase twice, as well as their honeydew production related to results obtained at holm oaks visited by the native ant Lasius grandis. The percentage of tended colonies tended by Lasius neglectus was higher compared to the percentage tended by Lasius grandis. As a consequence, at the studied period, the invasive ant collected two fold of honeydew per tree related to the native ant. At holm oaks visited by Lasius neglectus or Lasius grandis colonies of Lachnus roboris fed mainly on acorn petiole or on their cap. However, there was not any difference of acorn production acorn or quality and sapling emergency or quality between these holm oaks.Both ant species mainly captured Pscoptera and Hoplocallis picta as source of proteins. The percentage of workers carrying insects or pieces of arthropods in its jaws was higher for Lasius grandis. Arthropod community and herbivory level was not modified due the presence of the invasive or the native ant. However, some particular groups showed differences of its abundance. At holm oaks visited by Lasius neglectus, spiders, weevils and aphids tended to increase its abundance while ladybird larvae (aphid predators) decreased markedly.Honeydew production that was not collected by ants may reach the soil dissolved in throughfall as dissolved organic carbon (DOC). Honeydew collection by Lasius neglectus decreased DOC content in throughfall. This result suggests that the invasive ant interrupts the flux of energy and matter between canopy and the soil surrounding holm oaks.In relation with belowground effects of Lasius neglectus soil nutrient content was higher beneath holm oaks visited by the invasive ant in relation to those trees visited by native ants. Soil microbial community was characterized by the presence of Lasius neglectus and microbial biomass tended to increase beneath holm oaks visited by this invasive ant. Depending on the study site, litter quality was lower at holm oaks visited by Lasius neglectus. Litter decomposition was not modified by the presence of the invasive ant.I conclude that Lasius neglectus presence modifies those below-aboveground components of the holm oak system that are directly or indirectly related to honeydew collection.

Degut als impactes ecològics i socioeconòmics causats per les invasions biològiques, la seva gestió s’ha convertit en un repte important i una prioritat pels gestors mediambientals. A Espanya, la informació sobre la gestió de les plantes exòtiques està força dispersa i, en general, no hi ha gaire flux d’informació entre el món acadèmic i el món de la gestió. Per aquests motius, el principal objectiu d’aquesta tesi ha estat aprofundir en les mesures de gestió de plantes exòtiques a Espanya, identificant les seves principals limitacions. Conèixer aquestes limitacions ens ha dut a plantejar‐nos els següents objectius específics: 1) Identificar les principals plantes exòtiques problemàtiques a Espanya i avaluar els criteris utilitzats a l’hora de prioritzar la seva gestió; 2) Identificar i classificar les espècies potencialment invasores per Espanya; 3) A nivell global, quantificar mitjançant un metaanalisi els impactes de les plantes invasores i les conseqüències de la seva eliminació en les comunitats natives; i 4) Com a cas d’estudi, avaluar l’eficàcia de l’eliminació manual de Carpobrotus sp. a la costa d’Andalusia, i la recuperació de la vegetació nativa. Tenint en compte que les mesures de control i eradicació d’espècies exòtiques són extremadament costoses és molt important prevenir l’entrada i l’establiment d’espècies potencialment invasores, així com garantir l'eficàcia de les mesures de gestió aplicades. Aquesta tesi omple una mica el buit d’informació entre el món acadèmic i el de la gestió, proporcionant informació als gestors ambientals per tal de millorar l’eficàcia de les mesures de gestió aplicades. Les principals conclusions són: I. Les invasions biològiques són considerades pels gestors ambientals un problema de prioritat mitjana i un total de 109 plantes exòtiques problemàtiques han estat gestionades. II. La gestió de les plantes exòtiques s'ha centrat principalment en l'aplicació de mesures de control mecànic o químic a escala local i dissenyades, normalment, amb objectius a curt termini. Existeix, per tant, una manca de mesures de prevenció, mesures de seguiment a llarg termini i de pautes per a la priorització de la gestió d’espècies exòtiques. III. Mitjançant l'ús d'esquemes d'avaluació de riscos, s'ha elaborat una llista preliminar de 80 espècies potencialment invasores per Espanya, sent la jardineria la principal via d’entrada d’aquestes espècies. Les espècies amb les puntuacions més altes han resultat ser principalment plantes aquàtiques, i s’hauria de prohibir la seva entrada i comerç. Chromolaena odorata (Asteraceae) és l’espècie amb les puntuacions més altes i, per tant, podria ser considerada l'espècie amb major risc d'esdevenir invasora a Espanya, en cas que s'introduís al medi natural. IV. Aquesta tesi presenta un marc conceptual que compara llocs envaïts, llocs de referència no envaïts i llocs on una determinada espècie invasora ha estat eliminada. Aquestes comparacions permeten quantificar el impacte de l’espècie invasora en qüestió i supervisar la recuperació de les plantes natives després de la seva eliminació. En estudis científics, aquestes comparacions no solen ser utilitzades de manera combinada, i els llocs de referència són poc emprats per avaluar la recuperació d'espècies natives després de l'eliminació. Creiem que l’ús d’aquest enfocament comparatiu hauria de ser més emprat per supervisar l’eficàcia de les mesures de gestió, perquè a més, permet avaluar els possibles efectes secundaris de les tècniques d'eliminació, així com la necessitat de dur a terme mesures de restauració específiques a posteriori. V. La revisió bibliogràfica global demostra que les plantes invasores són responsables d'una disminució local en la riquesa i abundància d'espècies natives. Això, ha estat corroborat pel cas d’estudi sobre l’eliminació de Carpobrotus, on aquesta espècie també redueix significativament la riquesa d'espècies natives en les comunitats que envaeix. VI. En general, després de l'eliminació de les plantes invasores, la vegetació nativa té el potencial de recuperar‐se fins arribar als nivells desitjats previs a la invasió. / Now that the increasing impacts and costs of invasive species are being recognized, management of alien species has become an important challenge and a high priority for environmental managers. However, in Spain, management information on alien plants is quite scattered and, in general, there is a lack of communication between managers and scientists. The general aim of this thesis has been to investigate the management measures on alien plants carried out in Spain and to identify the main limitations of these measures. Once knowing these limitations the following specific objectives have been addressed: 1) To identify the most problematic invasive plant species in Spain and to assess the main criteria used to prioritize their management; 2) To identify and rank potentially invasive species in Spain, not present in the wild yet; 3) To quantify at a global scale, by means of a meta‐analysis, the impacts of invasive plants as well as the consequences of their removal over native communities, and 4) To evaluate, as a case study, the efficacy of the manual removal of Carpobrotus sp. in the coast of Andalucía, and the recovery of the native vegetation after the alien plant removal. Given that management measures are extremely costly in terms of human, technical and economic resources, it is really important to prevent potential invasive species as well as to guarantee management effectiveness in those cases where prevention is no longer a solution. This thesis have provided clear direction for bridging the current gap between the availability in information on alien plant species and the need for environmental managers to successfully prevent and control invasive species. Specifically, the main conclusions are: 1) Biological invasions are considered by Spanish environmental managers a medium priority problem and a total of 109 noxious alien species are being managed. 2) Management of alien plants in Spain has mainly focused, so far, in the application of either mechanical or chemical control measures at a local scale and mostly with short‐term goals in mind. Thus, there is a lack of preventive measures, absence of long‐term monitoring of control actions and few guidelines for prioritization. 3) By using risk assessment schemes, we have identified a preliminary list of 80 potential invasive species, being gardening the most common pathway of introduction. The species with the highest scores, were mainly aquatic plants, and should be prohibited or kept out of trade. Chromolaena odorata (Asteraceae) obtained the highest scores and therefore it might be the species with the highest risk to become invasive in Spain if introduced. 4) We have presented a conceptual framework that compares invaded, non‐invaded and removal sites to quantify invaders’ impacts and to monitor native plant recovery after their removal. In scientific studies, these comparisons are rarely used in concert, and reference sites are scarcely employed to assess native species recovery after removal. Thus, we believe that this comparative approach should be more frequently used to evaluate management effectiveness because it may also be useful to determine possible side‐effects of removal techniques and whether further restoration measures are necessary. 5) Our global literature review has demonstrated that invasion by alien plants is responsible for a local decline in native species richness and abundance. This has been corroborated by monitoring Carpobrotus invaded sites in coastal dunes of Andalucía, where this species has significantly decreased species richness in the communities it invades. 6) Our global literature review has also indicated that, in general, after alien plant removal, the native vegetation has the potential to recover to a pre‐invasion state. The same trend has been found in the case study of Carpobrotus.

Sensations of dizziness or fainting (pre-syncope or syncope) on standing up from a lying or a seated position are usually associated with impaired blood pressure regulation leading to inadequate perfusion of the brain. The purpose of this project was to develop a simple method to provide scientists and doctors a convenient way to monitor cardiovascular control during orthostatic stress with the non-invasive FinometerTM device. This apparatus provides a continuous estimate of arterial blood pressure (BP) contour from the finger and computes brachial blood pressure contours (systolic (SBP) and diastolic (DBP) blood pressure), heart rate (HR), stroke volume and cardiac output (Q) from the Modelflow equation. In this thesis, a method was implemented to obtain an estimate of central venous pressure (CVP) to provide greater insight into cardiovascular control. The accuracy and potential errors resulting from measurement of finger arterial pressure were also evaluated. The thesis first examined whether key variables essential to monitor cardiovascular control can be reliably measured by the FinometerTM in comparison to independent methods. HR was accurate and precise at rest and during stress (difference between methods: 0.05± 0.18 beats/min). According to standards established by the American Association for the Advancement of Medical Instrumentation (AAMI); at rest, DBP was accurate but not precise (1.6± 8.8 mmHg) and SBP was not accurate but precise (14.2± 8.0 mmHg). These errors could be due to an improper use of our reference method. The post-test correction for individual characteristics proposed by the FinometerTM developers did improve overall Q estimation (0.255± 0.441 L/min (6.9%) instead of 0.797± 0.441 L/min (22.4%)) when compared with Doppler ultrasound but did not account for the increasing error with a greater orthostatic stress induced by lower body negative pressure. Using finger BP instead of aortic BP to calculate Q did not explain this error as revealed by a new approach that compared the simultaneous pulse contours from different methods. Indeed, there was no significant difference between the error of the estimation of Q from the finger arterial pulse compared to the estimation of Q from the independent measurement by tonometry on the brachial artery at rest (-1.13± 14.67%) and at the maximum orthostatic stress used (-0.61± 9.33%) (p>0.05). Using brachial BP to calculate Q did not improve the result found with finger BP. The first hypothesis of this thesis that CVP could be estimated from outputs of the FinometerTM compared to direct venous pressure measurement was supported for the individual (0.2± 1.7 mmHg) and test specific (0.1± 1.2 mmHg) equations. The general equations derived from group data were accurate but not precise enough (0.4± 2.8 mmHg) to be used in clinical and research setting. The success of the individual equations suggests that it might be possible to derive a personal equation that will be useful over a long period for similar tests by using a catheter only once. The second and third hypotheses related to the cause of discrepancy between Q from FinometerTM and Q from Doppler, were not supported by the data. However, a new contour analysis method introduced here in a graphical format might provide an opportunity for systematic analyses of the deviation between methods. It could reveal sources of error allowing future improvements in the accuracy and precision of Q from FinometerTM during orthostatic or physical stress.

Bubble CPAP (BCPAP) is used in the neonatal intensive care unit (NICU) as a form of non-invasive ventilation and is commonly employed in neonates demonstrating respiratory distress. BCPAP may be used to avoid the need for intubation and mechanical ventilation thereby reducing lung injury and other morbidities as well as decrease hospital stay. PURPOSE: The purpose of this study is to retrospectively investigate the length of stay on bubble CPAP (BCPAP) considering gestational age, birth weight, and surfactant delivery in the neonatal population born at an urban tertiary high load level three (NICU). METHODS: A retrospective study using existing data from an urban tertiary high load level three NICU was completed. DATA ANALYSIS: Data analysis was performed using SPSS 16.0. Descriptive statistics were run for each variable. Contingency tables were run to determine if gestational age at birth, birth weight, and length of time on BCPAP had significance compared to surfactant delivery. Intercorrelations were run to determine if gestational age at birth, birth weight, and length of time on BCPAP had an effect on each other. Davis conventions were used to analyze the results. RESULTS: Descriptive statistics indicated the mean gestational age at birth to be 32.263 weeks, SD = +2.978, mean neonatal weight to be 1.899 kg, SD = +0.728, and mean length of time on BCPAP to be 124.430 hours, SD = +185.474. Contingency statistics showed a substantial association (reta = 0.562) between the gestational age at birth and surfactant delivery, a very strong association (reta = 1.000) between the birth weight and surfactant delivery, and a very strong association (reta = 0.914) between the length of time the neonate was on BCPAP and surfactant delivery. Pearson product-moment correlation coefficients showed gestational age at birth had a very strong positive association with birth weight (r = 0.811, p < 0.01) and a moderate negative association with length of time on BCPAP (r = -0.439, p < 0.01). Intercorrelations also showed birth weight had a moderate negative association with length of time on BCPAP (r = -0.306, p < 0.01). CONCLUSIONS: The neonate was less likely to receive surfactant if, their gestational age was older at birth, they had a heavier birth weight, and their length of time on BCPCP was shorter. The data also demonstrated that the older the neonate’s gestational age at birth and the heavier the neonatal birth weight equated to a shorter length of time on BCPAP. Lastly the data demonstrated that the heavier the neonate’s birth weight, the shorter length of time on BCPAP.

Roadsides in Sweden offer suitable habitats for species that naturally occur in the old agricultural landscape, a habitat that is less common today. These species are favored by small-scale disturbance such as of mowing which is to some extent applied in roadsides for management of the road surface. The Swedish Transport Administration has worked according to the environmental directives for sustainable populations of threatened species that occur along roadsides. Roadsides with threatened species and species that represent the old agriculture landscape have been located and described. Such roadsides have been named species rich roadsides (artrik vägkant) and can be found in different environments spread across the country. The Swedish Transport Administration has developed recommendations for special management to support species of old agricultural landscape in roadsides. Previous studies have shown a negative development of the species rich roadsides, with reduced numbers of species rich roadsides.  This project has analyzed whether there is a relationship between the management of species rich roadsides and the negative development of species rich roadsides, and also make recommendations for improving management methods needed for improving the development of species rich roadsides. Data have been used from previous inventories of species rich roadsides, the study area restricted to Region Mitt.  The present management of species rich roadsides has a significant negative effect of the development of species rich roadsides. To improve the development of species rich roadsides, management must be adapted to the environment the roadside is located to.

Sensations of dizziness or fainting (pre-syncope or syncope) on standing up from a lying or a seated position are usually associated with impaired blood pressure regulation leading to inadequate perfusion of the brain. The purpose of this project was to develop a simple method to provide scientists and doctors a convenient way to monitor cardiovascular control during orthostatic stress with the non-invasive FinometerTM device. This apparatus provides a continuous estimate of arterial blood pressure (BP) contour from the finger and computes brachial blood pressure contours (systolic (SBP) and diastolic (DBP) blood pressure), heart rate (HR), stroke volume and cardiac output (Q) from the Modelflow equation. In this thesis, a method was implemented to obtain an estimate of central venous pressure (CVP) to provide greater insight into cardiovascular control. The accuracy and potential errors resulting from measurement of finger arterial pressure were also evaluated. The thesis first examined whether key variables essential to monitor cardiovascular control can be reliably measured by the FinometerTM in comparison to independent methods. HR was accurate and precise at rest and during stress (difference between methods: 0.05± 0.18 beats/min). According to standards established by the American Association for the Advancement of Medical Instrumentation (AAMI); at rest, DBP was accurate but not precise (1.6± 8.8 mmHg) and SBP was not accurate but precise (14.2± 8.0 mmHg). These errors could be due to an improper use of our reference method. The post-test correction for individual characteristics proposed by the FinometerTM developers did improve overall Q estimation (0.255± 0.441 L/min (6.9%) instead of 0.797± 0.441 L/min (22.4%)) when compared with Doppler ultrasound but did not account for the increasing error with a greater orthostatic stress induced by lower body negative pressure. Using finger BP instead of aortic BP to calculate Q did not explain this error as revealed by a new approach that compared the simultaneous pulse contours from different methods. Indeed, there was no significant difference between the error of the estimation of Q from the finger arterial pulse compared to the estimation of Q from the independent measurement by tonometry on the brachial artery at rest (-1.13± 14.67%) and at the maximum orthostatic stress used (-0.61± 9.33%) (p>0.05). Using brachial BP to calculate Q did not improve the result found with finger BP. The first hypothesis of this thesis that CVP could be estimated from outputs of the FinometerTM compared to direct venous pressure measurement was supported for the individual (0.2± 1.7 mmHg) and test specific (0.1± 1.2 mmHg) equations. The general equations derived from group data were accurate but not precise enough (0.4± 2.8 mmHg) to be used in clinical and research setting. The success of the individual equations suggests that it might be possible to derive a personal equation that will be useful over a long period for similar tests by using a catheter only once. The second and third hypotheses related to the cause of discrepancy between Q from FinometerTM and Q from Doppler, were not supported by the data. However, a new contour analysis method introduced here in a graphical format might provide an opportunity for systematic analyses of the deviation between methods. It could reveal sources of error allowing future improvements in the accuracy and precision of Q from FinometerTM during orthostatic or physical stress.

The horticultural industry is responsible for approximately half of the invasive plant introductions in North America. To reduce these introductions, voluntary initiatives are preferred over government regulations. This thesis aims to evaluate the effectiveness of two types of voluntary initiatives. At the gardener level, I investigated the effectiveness of alternative species promotion campaigns, called “Grow Me Instead” programs. Adult gardeners visiting the Royal Botanical Gardens in Hamilton, Ontario, as well as customers at two garden centres, participated in a conjoint analysis which measured their preferences for various traits of potential ground cover species. Results showed that gardeners generally prefer plant species having invasive characteristics, suggesting these programs may not be as effective as initially believed. At the retailer level, this study aimed to build upon the work done by Burt and colleagues (2007) to obtain further understanding of the relative strength of internal (ethical motivations) and external (legislation, stakeholder pressures and economic opportunities) factors for motivating participation in voluntary initiatives. Telephone interviews were conducted with 30 industry professionals from southern Ontario to assess their adoption of the St. Louis Voluntary Codes of Conduct. Results found that participation rates of industry professionals in southern Ontario were lower for every specific initiative than those interviewed by Burt et al. (2007). Industry professionals presently experience the most pressure to participate from a sense of personal responsibility and the desire to create a green business image. Pressure was significantly higher from these sources than from pressure from employees. Together these two studies identified several barriers to the efficacy of voluntary initiatives as well as some reasons for optimism. To ensure the success of future voluntary initiatives, efforts must be made to encourage these two groups to work together. Understanding how both retailers and gardeners respond to voluntary initiatives will assist in the development of more effective programs and lead to fewer horticultural invasive species introductions in the future.

A lake-wide benthic survey of Lake Erie during summer 2002 indicated that Dreissena bugensis is the dominant dreissenid in Lake Erie, especially in the east basin where this species was found at every station but no Dreissena polymorpha were collected. Mean (±SD) densities of dreissenid mussels were comparable between the west (601±2,110/m2,n=49) and central (635±1,293/m2; n=41) basins, but were much greater in the east basin (9,480±11,173/m2;n=17). The greater variability in mussel density among stations and replicate samples in the central and west basins than in the east basin is attributable to the preponderance of fine-grained substrata in the nearshore, higher episodic rates of sediment deposition and periodic hypoxia in bottom waters. Although there was little change in lake-wide mean dreissenid densities between 1992 and 2002 (declining from ca. 2,636 individuals/m2 to 2,025 individuals/m2), basin-averaged shell-free dry tissue mass increased by almost four-fold from ca. 6.8±15.6 g /m2 to 24.7±71.3 g/m2 in the same interval. Up to 90% of this biomass is in the eastern basin. Other changes in 2002 include the virtual absence of mussels in the 3 to 12 mm size range, probably because of predation by round gobies, and an increase in the average size of mature mussels. The substantial changes observed between 1992 and 2002 suggest that dreissenid populations in Lake Erie were still changing rapidly in abundance and biomass, as well as species composition. The results of this survey suggest that a direct link between Dreissena spp. and hypolimnetic hypoxia in the central basin is unlikely. The dominant organisms of Lake Erie in 2002 were D. rostriformis bugensis (38%), Oligochaeta (33%), Chironomidae (18%), Sphaeriidae (2.7%), Amphipoda (2.3%) and Hydrozoa (2.2%). Mean invertebrate density was greater in the east basin, especially on hard substrates, than either the west or central basin. In the central basin, sites ≥5m supported greater numbers of organisms, than shallow (≤2m) sites in the nearshore wave zone. The greatest number of taxa were observed in the central basin, likely a resutlt of greater sampling effort there. Gammarus fasciatus comprised 80% of all amphipods, being most abundant on Dreissena-dominated hard substrates in the east basin. The introduced species, Echinogammarus ischnus occured at only 11 of 69 sites, and was the only amphipod found at 4 east basin sites, but at relatively low densities. Diporeia were not found in our survey. Hexagenia was collected at only 4 stations, all in the west basin. Chironomids were dominated by Tanytarsus and Chironomus, with Procladius, Dicrotendipes and Polypedilum also being relatively common. Oligochaete Trophic Index for 2002 indicates a similarly mesotrophic condition throughout the lake and marginal nutrient enrichment of sediments between years 1979-2002. Multivariate ordination of community data indicates clear separation of sites by year and basin as expected given the extirpation of Diporeia and the introduction of Dreissena and E. ischnus, but also reveals subtle changes in benthic structure over the last 2 decades. The benthic community of Lake Erie in 2002 does not likely represent an equilibrium condition.

Point Pelee National Park in Ontario, Canada has been affected by a long history of human activity. This activity has encouraged the establishment of approximately 276 exotic invasive plant species. These plants decrease biodiversity and effective function of ecosystems within the Park. A 5 Year Exotic Plant Species Management Plan for the Park was written in 1990. Since that time inventories have been done on some of the species but a monitoring of all the high priority exotic invasive plants has not. As part of this study an inventory of the high priority exotic invasive plants and their spatial extent in the Park, was created. From May to September, 2011 a comprehensive inventory took place within a 5.5km stretch in the terrestrial area at the southern end of the Park. Systematic belt transects were performed, on foot, from west to east at 100 m intervals. Within the quadrats percent cover of each plant species was determined. The data collected in the field were compiled using geographic information systems (GIS), resulting in maps of the extent of the most abundant species studied. Analysis as part of this study included using the data to determine which plants and areas are higher priorities for management within the Park. Quadrats were analysed for diversity using the Simpson Index and, since the data was non-parametric, comparisons were made across diversity and native richness using the Kruskal Wallis test. Alliaria officinalis is the only non-native species that is widespread within the study area. Other non-native species with a high potential for invasiveness were observed but only consisted of a few individuals along roads and paths. Some non-native species were present along or near roads and paths in denser patches (17-100% plot coverage). Recommendations include removal of some non-native species deemed to be a potential threat to native richness and diversity, followed by re-vegetation with native species, and continued monitoring. Future restoration efforts are best directed at the area around DeLaurier, along west beach and at the Tip. These areas have the lowest diversity and native richness and therefore need the most improvement.

Invasive species are capable of causing considerable damage to natural ecosystems, agricultures and economies throughout the world. These invasive species must be identified and adequate control measures should be investigated to prevent and reduce the negative effects associated with exotic species. A recent introduction of an exotic ant, Paratrechina sp. nr. pubens, has caused tremendous economic and ecological damage to southern Texas. Morphometric and phylogenetic procedures were used to identify this pest ant, P. sp. nr. pubens, to Southern Texas. The populations in Texas were found to be slightly different but not discriminating from P. pubens populations described in previous literature. Analysis of the distribution and expansion of P. sp. nr. pubens found numerous geographically discrete populations and moderately expanding territories. These expansion rates were determined to be ~20 and ~30 m per mo for a neighborhood and industrial area, respectively. Several laboratory and field control strategies were implemented for control of this intensely pestiferous species. Dinotefuran exhibited high laboratory efficacy against P. sp. nr. pubens, while treatments using novaluron were inconclusive. The use of expanded-use Termidor� demonstrated trends in these data that suggest it as the treatment of choice. Other field treatments, such as Termidor and Top Choice�, Termidor and Advance Carpenter Ant BaitTM, and Transport� and Talstar� G, did not attain the success found in the expanded-use Termidor treatment. Most treatments examined were determined ineffective against high populations of P. sp. nr. pubens. Additional and more intensive population management regimes should be investigated. Abating further P. sp. nr. pubens population proliferation to other regions will only be realized from additional control research supplemented with state and federal interdiction policies.