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Great Lakes Region (great + lake_region)
Kinds of Great Lakes Region Selected AbstractsHybridization dynamics of invasive cattail (Typhaceae) stands in the Western Great Lakes Region of North America: a molecular analysisJOURNAL OF ECOLOGY, Issue 1 2010Steven E. Travis Summary 1.,By increasing vigour and broadening ecological tolerances, hybridization between native and introduced species may serve as a primary driver of invasiveness. 2.,Cattails (Typha, Typhaceae) are clonal wetland graminoids that are known to hybridize where anthropogenic influences have resulted in distributional overlap. 3.,In order to gauge the relative performance of hybrid vs. pure Typha, we characterized hybridization and clonal growth where native Typha latifolia and introduced Typha angustifolia occur together in the Western Great Lakes Region of North America. 4.,Based on microsatellite markers, we documented F1 hybrids as the most common class at five intensively sampled sites, constituting up to 90% of the genets and 99% of the ramets. Backcrosses to one or the other parent constituted 5,38% of the genets. Pure T. latifolia was rare and never constituted more than 12% of the genets. 5.,F1 hybrid genets achieved the highest mean ramet numbers at three sites, and were second in size only to T. angustifolia at two sites; however, these differences were not significant based on site-specific one-way anovas. 6.,F1 hybrids exhibited little height advantage over other Typha classes, although there was a general tendency for hybrids in relatively mixed stands to be among the tallest genets in shallow water, but among the shortest genets in deeper water. 7.,Native T. latifolia was found growing at the shallowest water depths at the only site where it was sufficiently abundant to be included in statistical comparisons. 8.,Synthesis. The role of hybridization in plant invasions can be difficult to confirm in the absence of molecular data, particularly for clonal species where the boundaries separating individuals are otherwise difficult to discern. Here, we used molecular markers to document the prevalence and performance of hybrid genets in five invasive Typha stands covering a broad area of the Western Great Lakes Region. We found an extremely high prevalence of F1 hybrids within mixed Typha stands. This, coupled with the typically larger sizes of hybrid genets, suggests that hybrids are capable of outperforming other Typha spp. and that hybridization has played an influential role in the North American cattail invasion. [source] The influence of an upper-level frontal zone on the Mack Lake Wildfire environmentMETEOROLOGICAL APPLICATIONS, Issue 2 2007Tarisa Zimet Abstract Meteorological assessment of wildland fire danger has traditionally involved the identification of several synoptic weather types empirically determined to influence wildfire spread. Specifically, in the Great Lakes Region, high wildfire danger is often witnessed in association with northwesterly synoptic-scale flow aloft. Such synoptic-scale flow is regularly associated with the development of upper-level frontal zones also known as upper-level jet/front systems, which are often characterised by intrusions of stratospheric air into the troposphere. The notion that upper-frontal development can play an important role in promoting wildfire spread is advanced through interrogation of the output from a fine-scale numerical simulation of a documented explosive wildfire case; the Mack Lake Fire of May 1980. The Mack Lake case was characterised by a developing upper-level front embedded within a shortwave trough in the vicinity of the fire location. The upper-level front originated in northwesterly flow in central Canada as an upper-tropospheric ridge amplified over western North America. A thermally indirect circulation at the jet exit region both contributed to the intensification of the front and was associated with a maximum in quasi-geostrophic descent at mid-levels upstream of the fire region. The subsidence ushered dry air from the middle and upper-troposphere downward along sloping isentropes adiabatically warming and drying it along the way. A well-developed dry air intrusion associated with the operation of these processes extended to nearly the 750 hPa level far downstream from the actual upper-frontal zone supplying the fire environment with dry air that originated in the upper-troposphere/lower stratosphere. The organised subsidence was also responsible for downward advection of high momentum air from within the frontal zone into the fire environment, further influencing the wildfire spread. We conclude that upper-frontal processes, characteristic of northwesterly synoptic-scale flow, are likely a contributing factor to the prevalence of wildfire spread under such synoptic-scale conditions. Copyright © 2007 Royal Meteorological Society [source] The role of Late Holocene climate variability in the expansion of yellow birch in the western Great Lakes regionDIVERSITY AND DISTRIBUTIONS, Issue 5 2002Stephen T. Jackson Abstract. Pollen records from the western Great Lakes region of North America show substantial increases in birch pollen percentages during the late Holocene. The vegetational and population dynamics underlying the birch increase have received little attention, in part because of the inability to discriminate among species of birch based on pollen morphology. We used analyses of pollen and plant macrofossils from four lakes in the Upper Peninsula of Michigan to document that the birch pollen increase represents a regional expansion of yellow birch (Betula alleghaniensis) populations, which was initiated c. 4500 years ago. Whether yellow birch invaded the region at this time or simply expanded from small, previously established populations is not clear, although it probably did not grow near our study sites before the expansion. The initial expansion occurred during an independently documented period of high moisture and high water levels in Lake Michigan. A subsequent expansion in yellow birch abundance and distribution occurred c. 3000 years ago, coinciding with a second period of increased moisture and high lake-levels. The yellow birch expansion may have been modulated by millennial-scale climate variability, with most rapid expansion occurring during relatively wet periods. [source] Assessing the potential for fish predation to impact zebra mussels (Dreissena polymorpha): insight from bioenergetics modelsECOLOGY OF FRESHWATER FISH, Issue 2 2004M. A. Eggleton Abstract,,, Rates of annual food consumption and biomass were modeled for several fish species across representative rivers and lakes in eastern North America. Results were combined to assess the relative potential of fish predation to impact zebra mussels (Dreissena polymorpha). Predicted annual food consumption by fishes in southern waters was over 100% greater than that in northern systems because of warmer annual water temperatures and presumed increases in metabolic demand. Although generally increasing with latitude, biomasses of several key zebra mussel fish predators did not change significantly across latitudes. Biomasses of some less abundant fish predators did increase significantly with latitude, but increases were not of the magnitude to offset predicted decreases in food consumption. Our results generally support the premise that fishes in rivers and lakes of the southern United States (U.S.) have inherently greater potential to impact zebra mussels by predation. Our simulations may provide a partial explanation of why zebra mussel invasions have not been as rapid and widespread in southern U.S. waters compared to the Great Lakes region. Resumen 1Modelamos la tasa de consumo anual de alimento y biomasa para varias especies de peces en una muestra representativa de ríos y lagos del este de Norte América. Combinamos los resultados para evaluar el potencial relativo que estas especies de peces pueden ejercer sobre la abundancia del mejillón asiático Dreissena polymorpha. Las predicciones sobre consumo para peces en lagos y ríos del sur fueron más del 100% comparadas con sistemas septentrionales. Esto se puede deber a las temperaturas anuales más altas y aumentos en la demanda metabólica de peces en ríos y lagos del sur de Norte América. 2La biomasa de varias especies claves de peces que consumen D. polymorpha no cambió apreciablemente con latitud. La biomasa de algunos peces que consumen D. polymorpha aumentó significativamente con latitud, pero este aumento no era de una magnitud suficiente para compensar la disminución en el consumo de alimento. 3Nuestros resultados apoyan generalmente la premisa de que los peces en ríos y lagos del sur de los Estados Unidos (EE.UU.) tienen un potencial inherente mayor para poder controlar D. polymorpha. Nuestras simulaciones proporcionan una explicación parcial de por qué las invasiones de D. polymorpha no han sido tan rápidas y ampliamente distribuidas en aguas sureñas comparado con la región de los Grandes Lagos. [source] Diel interactions between prey behaviour and feeding in an invasive fish, the round goby, in a North American riverFRESHWATER BIOLOGY, Issue 4 2006STEPHANIE M. CARMAN Summary 1. We studied the diet of the invasive round goby (Neogobius melanostomus) on a diel basis in the Flint River, a warmwater stream in Michigan, U.S.A. Diet and available prey samples were collected seven times over a 24 h period in four consecutive months. The section of river studied lacked zebra mussels (Dreissena polymorpha), the primary prey of adult round gobies elsewhere in the Great Lakes region. 2. Diet changed on a diel basis with hydropsychid caddisfly and chironomid larvae predominating during the day, chironomid pupae dominating in the evening and heptageniid mayflies dominating at night. Simultaneous study of macroinvertebrate drift suggested that caddisfly and chironomid larvae were most likely picked from submerged rocks, chironomid pupae were most likely taken during their emergent ascent and mayflies were either captured from the drift or picked from rocks. 3. The Flint River lacks a diverse darter (Family: Percidae) and sculpin (Family: Cottidae) fauna and it appears that the round goby has occupied a generalised darter/sculpin niche. Our results indicate that round gobies have the potential to invade successfully riverine systems, particularly those lacking a diverse benthic fish assemblage. [source] Colored plastic and metal leg bands do not affect survival of Piping Plover chicksJOURNAL OF FIELD ORNITHOLOGY, Issue 3 2010Erin A. Roche ABSTRACT Leg bands are commonly used to mark shorebird chicks as young as 1-d old, but little is known about the possible impacts of bands on survival of prefledging shorebirds. We used a mark-recapture framework to assess the impact of bands and banding-related disturbance on prefledging survival in a federally endangered population of Piping Plovers (Charadrius melodus) breeding in the Great Lakes region from 2000 to 2008. We banded approximately 96% of all surviving chicks hatched prior to fledging, typically between 5 and 15 d of age. We used a multistate approach in program MARK whereby individuals contributed data as unbanded chicks before capture (N= 1073) and as banded chicks afterward (N= 780). The cumulative probability of surviving through 24 d of age was 0.63 and did not differ between banded and unbanded chicks. In addition, we found a positive effect of banding-related disturbance on survival up to 3 d following banding (,= 0.60 CI: 0.17,1.02), possibly due to increased postbanding vigilance on the part of chicks and adults. Our results indicate that banding has no detrimental effect on survival of Piping Plover chicks prior to fledging and that current capture and banding methods are appropriate for this endangered species. RESUMEN Los anillos son comúnmente utilizados para marcar los polluelos de aves playeras desde edades tempranas como un día de eclosionados, pero poco se conoce sobre los posibles impactos que estos anillos puedan tener sobre la supervivencia antes de abandonar el nido en aves playeras. Usamos técnicas de marca recaptura para estimar el impacto de los anillos y disturbios asociados a este proceso en la supervivencia antes de abandonar el nido en una población federal en peligro de Charadrius melodus anidando en la región de los grandes lagos desde el 2000 hasta el 2008. Anillamos aproximadamente 96% de todos los polluelos que sobrevivieron después de la eclosión y antes de abandonar el nido, normalmente entre 5,15 días de nacidos. Usamos una aproximación de estado múltiple en el programa MARK en el cual se dividieron los datos en polluelos sin anillar antes de la captura (N= 1073) y polluelos después de ser anillados (N= 780). La probabilidad acumulada de supervivencia a través de 24 días de edad fue 0.63 y no existieron diferencias entre polluelos anillados y no anillados. Adicionalmente, encontramos un efecto positivo relacionado con el disturbio creado durante le anillamiento en la supervivencia hasta tres días después del anillamiento (,= 0.60 CI: 0.17,1.02), posiblemente debido al incremento de vigilancia después del anillamiento por parte de los polluelos y adultos. Nuestros resultados indican que el anillamiento no tiene efectos negativos sobre la supervivencia de polluelos de Charadrius melodus antes de abandonar el nido y que los métodos de anillamiento y captura actualmente utilizados son apropiados para esta especie en peligro. [source] Effects of genotype, elevated CO2 and elevated O3 on aspen phytochemistry and aspen leaf beetle Chrysomela crotchi performanceAGRICULTURAL AND FOREST ENTOMOLOGY, Issue 3 2010Leanne M. Vigue 1Trembling aspen Populus tremuloides Michaux is an important forest species in the Great Lakes region and displays tremendous genetic variation in foliar chemistry. Elevated carbon dioxide (CO2) and ozone (O3) may also influence phytochemistry and thereby alter the performance of insect herbivores such as the aspen leaf beetle Chrysomela crotchi Brown. 2The present study aimed to relate genetic- and atmospheric-based variation in aspen phytochemistry to C. crotchi performance (larval development time, adult mass, survivorship). The experiment was conducted at the Aspen Free-Air CO2 Enrichment (FACE) site in northern Wisconsin. Beetles were reared on three aspen genotypes under elevated CO2 and/or O3. Leaves were collected to determine chemical characteristics. 3The foliage exhibited significant variation in nitrogen, condensed tannins and phenolic glycosides among genotypes. CO2 and O3, however, had little effect on phytochemistry. Nonetheless, elevated CO2 decreased beetle performance on one aspen genotype and had inconsistent effects on beetles reared on two other genotypes. Elevated O3 decreased beetle performance, especially for beetles reared on an O3 -sensitive genotype. Regression analyses indicated that phenolic glycosides and nitrogen explain a substantial amount (27,45%) of the variation in herbivore performance. 4By contrast to the negative effects that are typically observed with generalist herbivores, aspen leaf beetles appear to benefit from phenolic glycosides, chemical components that are largely genetically-determined in aspen. The results obtained in the present study indicate that host genetic variation and atmospheric concentrations of greenhouse gases will be important factors in the performance of specialist herbivores, such as C. crotchi, in future climates. [source] Selective manipulation of predators using pheromones: responses to frontalin and ipsdienol pheromone components of bark beetles in the Great Lakes regionAGRICULTURAL AND FOREST ENTOMOLOGY, Issue 3 2005Brian H. Aukema Abstract 1,One proposed approach to improving biological control of bark beetles (Coleoptera: Scolytidae; alt. Curculionidae: Scolytinae) is to manipulate predator movement using semiochemicals. However, selective manipulation is impeded by attraction of both predators and pests to bark beetle pheromones. 2,The primary bark beetle affecting pine plantations in Wisconsin, U.S.A., is the pine engraver, Ips pini (Say). Other herbivores include Ips grandicollis (Eichhoff) and Dryophthorus americanus Bedel (Curculionidae). The predominant predators are the beetles Thanasimus dubius (Cleridae) and Platysoma cylindrica (Histeridae). 3,We conducted field assays using two enantiomeric ratios of ipsdienol, and frontalin plus ,-pinene. Ipsdienol is the principal pheromone component of I. pini, and frontalin is produced by a number of Dendroctonus species. ,-Pinene is a host monoterpene commonly incorporated into commercial frontalin lures. 4,Thanasimus dubius was attracted to frontalin plus ,-pinene, and also to racemic ipsdienol. By contrast, I. pini was attracted to racemic ipsdienol, but showed no attraction to frontalin plus ,-pinene. Platysoma cylindrica was attracted to 97%-(,)-ipsdienol and, to a lesser extent, racemic ipsdienol, but not to frontalin plus ,-pinene. Ips grandicollis was attracted to frontalin plus ,-pinene but not to ipsdienol. Dryophthorus americanus was attracted to both ipsdienol and frontalin plus ,-pinene. 5,This ability to selectively attract the predator T. dubius without attracting the principal bark beetle in the system, I. pini, provides new opportunities for research into augmentative biological control and basic population dynamics. Moreover, the attraction of T. dubius, but not P. cylindrica, to frontalin plus ,-pinene creates opportunities for selective manipulation of just one predator. 6,Patterns of attraction by predators and bark beetles to these compounds appear to reflect various degrees of geographical and host tree overlap with several pheromone-producing species. [source] Effect of varying monoterpene concentrations on the response of Ips pini (Coleoptera: Scolytidae) to its aggregation pheromone: implications for pest management and ecology of bark beetlesAGRICULTURAL AND FOREST ENTOMOLOGY, Issue 4 2003Nadir Erbilgin Abstract 1,Host plant terpenes can influence attraction of conifer bark beetles to their aggregation pheromones: both synergistic and inhibitory compounds have been reported. However, we know little about how varying concentrations of individual monoterpenes affect responses. 2,We tested a gradient of ratios of ,-pinene, the predominant monoterpene in host pines in the Great Lakes region of North America, to Ips pini's pheromone, racemic ipsdienol plus lanierone. 3,Ips pini demonstrated a parabolic response, in which low concentrations of ,-pinene had no effect on attraction to its pheromone, intermediate concentrations were synergistic and high concentrations were inhibitory. These results suggest optimal release rates for population monitoring and suppression programmes. 4,Inhibition of bark beetle attraction to pheromones may be an important component of conifer defences. At terpene to pheromone ratios emulating emissions from trees actively responding to a first attack, arrival of flying beetles was low. This may constitute an additional defensive role of terpenes, which are also toxic to bark beetles at high concentrations. 5,Reduced attraction to a low ratio of ,-pinene to pheromone, as occurs when colonization densities become high and the tree's resin is largely depleted, might reflect a mechanism for preventing excessive crowding. 6,Thanasimus dubius, the predominant predator of I. pini, was also attracted to ipsdienol plus lanierone, but its response differed from that of its prey. Attraction increased across all concentrations of ,-pinene. This indicates that separate lures are needed to sample both predators and bark beetles effectively. It also provides an opportunity for maximizing pest removal while reducing adverse effects on beneficial species. This disparity further illustrates the complexity confronting natural enemies that track chemical signals to locate herbivores. [source] Wolves in the Great Lakes region: a phylogeographic puzzleMOLECULAR ECOLOGY, Issue 20 2010ETTORE RANDI Empirical studies demonstrate that natural hybridization in animals is more common than thought so far (Mallet 2005), particularly among species that originated recently through cycles of population contraction,expansion arising from climate changes over the last glacial period, the Pleistocene. In addition, the post-glacial global growth of human populations has fostered anthropogenic hybridization events, mediated by habitat changes, the persecution of large predators and the introduction of alien species (Allendorf et al. 2001). The Canis lineage shows cases of both natural and anthropogenic hybridization, exacerbating the controversy about the number of species that should be formally validated in the taxonomic lists, the evolutionary role of genetic introgression and the ways to manage hybrids with invading wild or domesticated populations. The study by Wheeldon et al. (2010), published in this issue of Molecular Ecology, adds a new piece to the intricate puzzle of evolution and taxonomy of Canis in North America. They show that sympatric wolves (C. lupus) and coyotes (C. latrans) are not (extensively) hybridizing in the western North American Great Lakes region (GLR). Widespread hybridization between coyotes and a genetically distinct, but closely related, wolf-like population (the eastern wolf) occurred in the northeastern regions of North America. In Wheeldon et al.'s (2010) opinion, these data should prove definitely that two different species of wolf (the western gray wolf C. lupus and the eastern wolf C. lycaon) and their hybrids are distributed across the GLR. [source] Distinctiveness in the face of gene flow: hybridization between specialist and generalist gartersnakesMOLECULAR ECOLOGY, Issue 18 2008BENJAMIN M. FITZPATRICK Abstract Patterns of divergence and polymorphism across hybrid zones can provide important clues as to their origin and maintenance. Unimodal hybrid zones or hybrid swarms are composed predominantly of recombinant individuals whose genomes are patchworks of alleles derived from each parental lineage. In contrast, bimodal hybrid zones contain few identifiable hybrids; most individuals fall within distinct genetic clusters. Distinguishing between hybrid swarms and bimodal hybrid zones can be important for taxonomic and conservation decisions regarding the status and value of hybrid populations. In addition, the causes of bimodality are important in understanding the generation and maintenance of biological diversity. For example, are distinct clusters mostly reproductively isolated and co-adapted gene complexes, or can distinctiveness be maintained by a few ,genomic islands' despite rampant gene flow across much of the genome? Here we focus on three patterns of distinctiveness in the face of gene flow between gartersnake taxa in the Great Lakes region of North America. Bimodality, the persistence of distinct clusters of genotypes, requires strong barriers to gene flow and supports recognition of distinct specialist (Thamnophis butleri) and generalist (Thamnophis radix) taxa. Concordance of DNA-based clusters with morphometrics supports the hypothesis that trophic morphology is a key component of divergence. Finally, disparity in the level of differentiation across molecular markers (amplified fragment length polymorphisms) indicates that distinctiveness is maintained by strong selection on a few traits despite high gene flow currently or in the recent past. [source] Charisma, creativity, and cosmopolitanism: a perspective on the power of the new radio broadcasting in Uganda and Rwanda,THE JOURNAL OF THE ROYAL ANTHROPOLOGICAL INSTITUTE, Issue 4 2007Richard Vokes From the mid-1980s onwards, the number of charismatic leaders operating in the Great Lakes region of Eastern-Central Africa has risen dramatically. This article draws a connection between this rapid expansion of charismatic authority and the concurrent proliferation of new radio broadcasting cultures across the zone. It notes that practically every new leader who has emerged over the last two decades has engaged in some form of radio broadcasting, and that in a number of instances, such broadcasts have been central to a particular leader's very claim to power. It then examines the reasons why radio broadcasting has emerged as so important here. Through a detailed study of one charismatic leader, Kihura Nkuba , who rose to prominence in Southwestern Uganda in 1999 , the article argues that the power of the new radio broadcasting stems from the ,cosmopolitan' subject position it engenders amongst listeners. However, this is a quite different form of cosmopolitanism which is at least partly unintended, or involuntary (and stems from the insertion of a ,global' technology , i.e. the physical radio set , into the listening context). Yet it is still compelling, a fact which helps us to understand why some listeners of these broadcasts have been motivated , after listening to charismatic leaders' broadcasts , to engage in extreme, socially abnormal, acts. The article goes on to argue that this provides a perspective from which to understand events in Rwanda in 1994, when radio listeners were induced, by a group of charismatic radio presenters (on the station Radio-Télévision Libre des Mille Collines, RTLM) to participate in genocidal killings. Résumé Depuis le milieu des années 1980, le nombre de chefs charismatiques a considérablement augmenté dans la région des Grands Lacs d'Afrique centrale et orientale. L'auteur établit ici un lien entre l'expansion rapide de l'autorité charismatique et la prolifération en parallèle de nouvelles cultures de la radiodiffusion dans cette zone. Il note que tous les nouveaux chefs, ou presque, qui sont apparus au cours des deux dernières décennies sont présents sur les ondes de multiples manières. Cette présence radiophonique est souvent un élément essentiel de leurs revendications de pouvoir. Il examine ensuite les raisons de l'importance des émissions de radio dans cette région. Par le biais d'une étude détaillée de l'un de ces chefs charismatiques, Kihura Nkuba, qui s'est fait connaître en 1999 dans le Sud-ouest de l'Ouganda, l'article montre que le pouvoir des nouvelles émissions de radio tient au positionnement en tant que sujet « cosmopolite » qu'elles suscitent parmi leurs auditeurs. Il s'agit toutefois d'une forme de cosmopolitisme très différente, au moins partiellement fortuite ou involontaire (et née de l'insertion d'une technologie « globale », le récepteur de radio lui-même, dans le contexte d'audition). Cette captivation peut nous aider à comprendre comment les auditeurs de ces émissions ont pu être incités, après avoir écouté les émissions de leurs chefs charismatiques, à s'engager dans des actes extrêmes et anomiques. L'auteur affirme que cette approche peut éclairer les événements de 1994 au Rwanda, qui ont vu les auditeurs des radios incités par un groupe de présentateurs charismatiques (ceux de la Radio-Télévision Libre des Mille Collines, RTLM), à participer à des massacres génocidaires. [source] A Place Where I Can Let My Hair Down: from social club to cultural center in an urban Indian communityCITY & SOCIETY, Issue 1 2001Deborah Davis Jackson The "Riverton" Indian Center was established in the 1950s as large numbers of Native Americans migrated to the city from reservations around the Great Lakes and beyond, and underwent significant changes throughout the second half of the twentieth century. These changes, and the conflicts that resulted from them, were shaped by far larger political,economic and cultural forces: on the one hand, River ton's economy, along with the economies of many midsized cities in the Great Lakes region,was undergoing rapid deindustrialization with devastating consequences to local residents, including American Indians; on the other hand, social and cultural changes in the U.S., starting in the 1960s, made Native Americans,or at least a romanticized image of Native Americans,increasingly popular with non-Natives. These forces converged to create the three distinct phases in the Riverton Indian Center's history, each associated with a particular age cohort,a trajectory that might well be typical of deindustrializing cities in the Great Lakes region. [American Indians; community and identity; deindistrialivng cities; Upper Great Lakes region] [source] | ||||||||||||||||