Browsing by Subject "Biogeography"

Now showing 1 - 7 of 7
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    Communities in freshwater coastal rock pools of Lake Superior, with a focus on chironomidae (Diptera)
    (2014-05) Egan, Alexander
    Exposed freshwater shores have received little ecological attention. At Isle Royale, an archipelago in Lake Superior, coastal areas have a moderated climate due to the large, deep lake. This project was instigated because 1) little was known about coastal ecosystems at Isle Royale, 2) unique aquatic species were expected in this habitat, 3) potentially disastrous impacts from shipping accidents could cause population losses of sensitive species, and 4) long-term shifts in climate could influence communities via warming conditions and erratic precipitation. Focal habitats were pools on the open shore, formed in bedrock depressions from precipitation, ground water, overland flow, and wave wash. The focal study taxon was Chironomidae, a diverse family of aquatic flies, well-known for variable responses to pollution and ecological gradients. Results showed a surprisingly species-rich (n = 102) and diverse assemblage. Moderate to extreme range expansions and novel habitat use were documented. Distinct communities were observed between two vertical zones, based on distance from the lake. Differences in seasonal emergence occurred close to the lake, but emerging assemblages were similar across seasons above lake influence. Some evidence supported both biogeographic community variation based on distances between islands and control of emergence events by water temperature. However, there was no evidence that pool depth or potential for desiccation influenced chironomid occupancy. Nutrients (phosphorus, nitrogen, and carbon) were the most important factors driving chironomid assemblage differences. Pools higher on the shore showed nutrient input from upland habitats, while pools lower on the shore appeared to have nutrients flushed out by wave action and replaced with low-nutrient water. Comprehensive habitat mapping revealed high pool densities, with an extraordinary number on Passage Island, arguably the most threatened locality to shipping pollution. Also, Passage Island had the highest density of Pseudacris triseriata, a frog species with a remarkably narrow habitat use at Isle Royale. Overall, a diverse community was revealed in what superficially looks like unremarkable habitat. Apparent similarities to northern and western shores of Lake Superior suggest this study of basic aquatic ecology and physical structure describes reference conditions for coastal management across much of the lake.
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    Global biogeography and local adaptation of Streptomyces
    (2013-10) Schlatter, Daniel Cameron
    Streptomyces play crucial roles in key ecosystem processes including nutrient and plant disease suppression in natural and agricultural systems. Moreover, Streptomyces are major producers of clinically relevant antibiotic compounds. Despite the importance of Streptomyces in natural, agricultural, and clinical settings, we have a limited understanding of Streptomyces ecology and evolutionary biology in natural habitats. Here we characterize the function diversity and biogeography of Streptomyces to shed light on the roles of local adaptation and coevolution in structuring soil Streptomyces communities. Specifically, this work focuses on patterns of antibiotic inhibition, antibiotic resistance, resource use, and phylogeny among sympatric and allopatric Streptomyces communities from across the globe. This work documents the extensive functional diversity of Streptomyces antibiotic inhibitory, resistance, and resource use phenotypes and provides strong evidence that local adaptation, coevolution, and resource competition are crucial drivers of antibiotic inhibition and resistance among Streptomyces.
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    Human Influences on Water Quality in Great Lakes Coastal Wetlands
    (2008) Morrice, John A; Danz, Nick; Regal, Ronald R; Kelly, John R; Niemi, Gerald J; Reavie, Euan; Hollenhorst, Thomas; Axler, Richard P; Trebitz, Annet; Cotter, Anne C; Peterson, Gregory S
    This peer-reviewed article discusses water quality and chemistry issues with anthropogenic causes. Geographically, it covers the US coastal region of the Great Lakes. A map in the article suggests that only one sampling point was within Minnesota’s coastal region. The article focuses on water chemistry in coastal wetlands across the Great Lakes, but not specifically for Minnesota. Key points in the abstract are extracted and reproduced below. A better understanding of relationships between human activities and water chemistry is needed to identify and manage sources of anthropogenic stress in Great Lakes coastal wetlands. The objective of the study described in this article was to characterize relationships between water chemistry and multiple classes of human activity (agriculture, population and development, point source pollution, and atmospheric deposition). We also evaluated the influence of geomorphology and biogeographic factors on stressor-water quality relationships. We collected water chemistry data from 98 coastal wetlands distributed along the United States shoreline of the Laurentian Great Lakes and GIS-based stressor data from the associated drainage basin to examine stressor-water quality relationships. The sampling captured broad ranges (1.5–2 orders of magnitude) in total phosphorus (TP), total nitrogen (TN), dissolved inorganic nitrogen (DIN), total suspended solids (TSS), chlorophyll a (Chl a), and chloride; concentrations were strongly correlated with stressor metrics. Hierarchical partitioning and all-subsets regression analyses were used to evaluate the independent influence of different stressor classes on water quality and to identify best predictive models. Results showed that all categories of stress influenced water quality and that the relative influence of different classes of disturbance varied among water quality parameters. Chloride exhibited the strongest relationships with stressors followed in order by TN, Chl a, TP, TSS, and DIN. In general, coarse scale classification of wetlands by morphology (three wetland classes: riverine, protected, open coastal) and biogeography (two eco-provinces: Eastern Broadleaf Forest [EBF] and Laurentian Mixed Forest [LMF]) did not improve predictive models. This study provides strong evidence of the link between water chemistry and human stress in Great Lakes coastal wetlands and can be used to inform management efforts to improve water quality in Great Lakes coastal ecosystems.
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    Systematic studies of the caddisfly subfamily Protoptilinae (Trichoptera: Glossosomatidae)
    (2010-06) Robertson-Thompson, Desiree Ruth
    Protoptilinae Ross 1956, is the most diverse subfamily [268 species (including 5 fossil spp.) and 17 genera] belonging to the saddle- or tortoise-case making family Glossosomatidae. The subfamily has a disjunct distribution: 4 genera are known from the East Palaearctic and Oriental regions; the remaining 13 are restricted to the Nearctic and Neotropical regions. Monophyly of Protoptilinae and each of the 17 genera was tested using 80 taxa, 99 morphological characters, and mitochondrial DNA (COI). Additionally, homologies of morphological characters were assessed across genera and a standardized terminology for those structures was established. Mitochondrial DNA (COI) data was unavailable for 55 of the 80 taxa included in this study. To test the effects of including a large set of highly incomplete taxa, 5 different datasets were analyzed using both parsimony and Bayesian methods: TOTAL COMBO (80 taxa, morphology and COI); TOTAL MORPH (80 taxa, morphology); SUBSET COMBO (25 taxa, morphology and COI); SUBSET MORPH (25 taxa, morphology); and SUBSET COI (25 taxa, COI). There was incongruence between the COI and morphological data, but results suggest the inclusion of COI data in a combined analysis, although incomplete, improved the overall phylogenetic signal. Bayesian and parsimony analyses of all 5 datasets strongly supported the monophyly of Protoptilinae. Monophyly of the following genera was also supported: Canoptila, Culoptila, Itauara, Mastigoptila, Mortoniella, Protoptila, and Tolhuaca. Monophyly for the genera Campsiophora, Cariboptila, Cubanoptila, Nepaloptila, Padunia, and Poeciloptila was not supported. Several taxonomic changes were necessary for classification to reflect phylogeny. Accordingly, I proposed that Matrioptila (Ross 1938), Poeciloptila Schmid 1991, Temburongpsyche Malicky 1992, and Nepaloptila Kimmins 1964 all become new junior synonyms of Padunia Martynov 1910. Additionally, I proposed to that the endemic Caribbean genera Cariboptila Flint 1964 and Cubanoptila Sykora 1973 become new junior synonyms of Campsiophora Flint 1964. A key to the world genera of Protoptilinae incorporating these taxonomic changes was provided. Using a fossil-calibrated relaxed molecular clock analysis (based on mitochondrial DNA and ribosomal RNA), independent geologic evidence, climatology, and Bayesian dispersal-vicariance analysis (DIVA), I constructed a biogeographic scenario for Protoptilinae. Divergence time estimates indicated that Protoptilinae arose at the Paleocene-Eocene Boundary, well after the initial Mesozoic break-up of Gondwanaland. Most major protoptiline lineages diverged during the Eocene and most modern genera arose during the Oligocene. DIVA analyses suggested Tolhuaca to be a relict of a more widespread protoptiline ancestor whose distribution encompassed Central and South America. The timing of many lineage divergences were correlated to geologic events that would have facilitated faunal movement between land-masses. Island corridors between South and Central America allowed migration northward. The GAARlandia landspan (Greater Antilles + Aves Ridge) provided a route for protoptiline range expansion from northern South America to the Greater Antilles and its subsequent re-submergence led to the divergence of Campsiophora. The presence of Padunia in Asia resulted from migration across Beringia. Pleistocene glaciation may have caused the extinction of northern populations, resulting in Padunia’s present disjunct distribution. Nearly a third of all speciation events appear to be the result of dispersal, range expansion, or subsequent re-colonization. Species-level revisions of Canoptila, Itauara, and Tolhuaca were also presented, including generic diagnoses, illustrations, and descriptions of males. Females of Canoptila and Tolhuaca were described for the first time. Additionally, the first known record of Protoptila in Bolivia was reported and a review of the occurrence of scales and androconia in Trichoptera was provided. A total of 28 species were treated, 22 vii distribution. Nearly a third of all speciation events appear to be the result of dispersal, range expansion, or subsequent re-colonization. Species-level revisions of Canoptila, Itauara, and Tolhuaca were also presented, including generic diagnoses, illustrations, and descriptions of males. Females of Canoptila and Tolhuaca were described for the first time. Additionally, the first known record of Protoptila in Bolivia was reported and a review of the occurrence of scales and androconia in Trichoptera was provided. A total of 28 species were treated, 22 described as new: Canoptila williami (Brazil), new species, Itauara alexanderi, new species (Brazil), I. bidentata, new species (Guyana), I. blahniki, new species (Brazil), I. charlotta, new species (Brazil), I. emilia, new species (Brazil), I. flinti, new species described as new: Canoptila williami (Brazil), new species, Itauara alexanderi, new species (Brazil), I. bidentata, new species (Guyana), I. blahniki, new species (Brazil), I. charlotta, new species (Brazil), I. emilia, new species (Brazil), I. flinti, new speciesdescribed as new: Canoptila williami (Brazil), new species, Itauara alexanderi, new species (Brazil), I. bidentata, new species (Guyana), I. blahniki, new species (Brazil), I. charlotta, new species (Brazil), I. emilia, new species (Brazil), I. flinti, new species (Brazil), I. guianensis, new species (Guyana), I. jamesii, new species (Brazil), I. julia, new species (Brazil), I. lucinda, new species (Brazil), I. ovis, new species (Guyana, Venezuela), I. peruensis, new species (Peru), I. rodmani, new species (Brazil), I. simplex, new species (Brazil), I. spiralis, new species (Guyana), I. stella, new species (Brazil), I. tusci, new species (Brazil), I. unidentata, new species (Guyana), Protoptila diablita, new species (Bolivia), P. julieta, new species (Bolivia), and Tolhuaca brasiliensis, new species (Brazil).
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    Systematics, Biogeography, and Phylogeography of Thylamys Mouse Opossums, a Recent Radiation of Neotropical Marsupials
    (2013-08) Giarla, Thomas Christopher
    This project broadly explores the systematics, biogeography, and phylogeography of Thylamys mouse opossums, a genus of Neotropical marsupials from central and southern South America. Chapter 1 is part of a collaborative work with Robert Voss and Sharon Jansa (Chapter 1). In it, we resolve longstanding issues surrounding Thylamys taxonomy and nomenclature using mitochondrial DNA sequences and morphology, and provide the first phylogenetic hypothesis for all recognized species in this genus. We recognize nine species but also uncover numerous morphologically cryptic mitochondrial haplogroups within four species. In Chapter 2, I assess the evolutionary independence of a subset of these morphologically cryptic lineages within the montane species Thylamys pallidior, T. sponsorius, and T. venustus. I find evidence to support the existence of two lineages within each of the three species, and also conduct tests to determine the number of nuclear loci needed to confidently test species limits. In Chapter 3, I examine the biogeographic history of Thylamys and its monotypic sister-genus Lestodelphys, considering the impact of habitat type and physical barriers on range evolution and cladogenesis. In Chapter 4, I test predictions regarding the impact of late Quaternary glacial cycles on the evolutionary history of six montane cryptic lineages. I estimate divergence times and demographic shifts for each lineage, and find limited support for the core predictions. Two supplementary files are provided online as part of this dissertation: a file containing 15 phylogenetic trees for each of the loci considered in Chapter 2 (Online Supplementary File 1) and a file containing GenBank accession numbers and tissue voucher numbers for the sequences included in the supermatrix in Chapter 3 (Online Supplementary File 2).
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    Taxonomic Revision of the Pirate Perches (Percopsiformes: Aphredoderidae) Reveals Three New Species and Elevates Two Subspecies
    (2023-07) Muller, Tyler
    The Southeastern United States is home to exceptionally high fish diversity among temperate latitudes. Species richness and endemism in this region is commonly attributed to historic biogeographic processes dating back to the Pliocene or earlier, and influences of sea levels through a relatively old though stochastic landscape and drainage basins. Specific and subspecific differentiation within the Southeastern United States occurs over a small geographic area and is well documented, though several species of lowland fishes seemingly defy biogeographic and phylogeographic models and expand well beyond other species ranges without any hypotheses for dispersal. Pirate Perches, Aphredoderus, are a widespread lowland freshwater fish native to the Eastern half of the United States. Aphredoderus was thought to contain a single species divided into an Eastern and Western subspecies on either side of the Appalachian Mountains with a widespread intergrade zone through much of the Eastern Gulf of Mexico and Southern Atlantic drainages. I use morphology and ddRADseq from specimens spanning the entire range of the genus to determine species limits within Aphredoderus. I find evidence of five species, four of which exhibit widespread sympatry in the Southeastern United States. I elevate A. sayanus sayanus and A. sayanus gibbosus to species, supplement previous descriptions, and describe three new species, A breviopercularis sp. nov., A. retrodorsalis sp. nov., and A. ornatus sp. nov. This research suggests that expansion through the Pliocene and Pleistocene was differential and several different historic refugia existed to facilitate allopatric speciation similar to what is proposed in earlier biogeographic and phylogeographic studies.
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    Three keys to the radiation of angiosperms into freezing environments
    (Nature Publishing Group, 2014) Zanne, Amy E; Tank, David C; Cornwell, William K; Eastman, Jonathan M; Smith, Stephen A; FitzJohn, Richard G; McGlinn, Daniel J; O’Meara, Brian C; Moles, Angela T; Reich, Peter B; Royer, Dana L; Soltis, Douglas E; Stevens, Peter F; Westoby, Mark; Wright, Ian J; Aarssen, Lonnie; Bertin, Robert I; Calaminus, Andre; Govaerts, Rafaël; Hemmings, Frank; Leishman, Michelle R; Oleksyn, Jacek; Soltis, Pamela S; Swenson, Nathan G; Warman, Laura; Beaulieu, Jeremy M
    Early flowering plants are thought to have been woody species restricted to warm habitats1, 2, 3. This lineage has since radiated into almost every climate, with manifold growth forms4. As angiosperms spread and climate changed, they evolved mechanisms to cope with episodic freezing. To explore the evolution of traits underpinning the ability to persist in freezing conditions, we assembled a large species-level database of growth habit (woody or herbaceous; 49,064 species), as well as leaf phenology (evergreen or deciduous), diameter of hydraulic conduits (that is, xylem vessels and tracheids) and climate occupancies (exposure to freezing). To model the evolution of species’ traits and climate occupancies, we combined these data with an unparalleled dated molecular phylogeny (32,223 species) for land plants. Here we show that woody clades successfully moved into freezing-prone environments by either possessing transport networks of small safe conduits5 and/or shutting down hydraulic function by dropping leaves during freezing. Herbaceous species largely avoided freezing periods by senescing cheaply constructed aboveground tissue. Growth habit has long been considered labile6, but we find that growth habit was less labile than climate occupancy. Additionally, freezing environments were largely filled by lineages that had already become herbs or, when remaining woody, already had small conduits (that is, the trait evolved before the climate occupancy). By contrast, most deciduous woody lineages had an evolutionary shift to seasonally shedding their leaves only after exposure to freezing (that is, the climate occupancy evolved before the trait). For angiosperms to inhabit novel cold environments they had to gain new structural and functional trait solutions; our results suggest that many of these solutions were probably acquired before their foray into the cold.