Great river wood dynamics in northern Canada

2016 Summer.Includes bibliographical references.Downed wood is a resource easily utilized by plants and animals from the forests to the sea and is essential for many ecosystems. The diverse benefits that wood brings to streams and riparian corridors are well documented by river scientists and wood re-introduction is commonly used as a river restoration tool. However, much of the existing work investigates the short-term impact of wood rather than its variability through time and legacy on the landscape. In this dissertation, I use the Slave River (water discharge=2-7 x103 m3 s −1 , channel widths=300-2000 m, drainage area=6x105 km2 ), and its receiving sedimentary basin, the Great Slave Lake (surface area=273 km2 , depths 20-600 m, volume 1000-2000 km3 ), in northern Canada to better understand wood transport dynamics of a major river basin across varied timescales from minutes to centuries and the influence of driftwood on shoreline landscape evolution. The four primary contributions of this work are: a comprehensive literature review and synthesis of wood transport in rivers worldwide (Chapter 1), new methods for monitoring and quantifying wood flux with timelapse cameras (Chapter 2), description of processes among driftwood, sediment, and vegetation that result in shoreline features that I have coined "driftcretions" (Chapter 3), and expansion of wood transport research into multiple timescales with a focus on how flow history impacts magnitude of wood flux (Chapter 4). In Chapter 1, I: qualitatively summarize existing transport research around flow, wood and reach characteristics, quantitatively consolidate and analyze wood mobility field data in relation to increasing channel size, identify disconnects between driving processes and how mobility is measured, and constrain and conceptualize thresholds between wood dynamic ii regimes. In Chapter 2, I introduce a cheap, useful and fast way to monitor and estimate wood flux with timelapse photography through the use of the metric p, the probability of seeing wood within a timeframe, and I provide statistical methods to estimate appropriate sampling intervals to minimize bias and variance. In Chapter 3, I describe processes and rates by which pulsed driftwood export are delivered and accreted to shorelines and I discuss how these processes influence rates of carbon sequestration, sediment storage and habitat formation. In Chapter 4, I use a variety of methods centered around repeat photography and anecdotes to assess temporal variability of pulsed driftwood flux through the Slave River in the past century. Findings in this dissertation provide useful information for understanding pulsed wood flux, shoreline dynamics and landforms in marine and terrestrial water bodies before widespread historical deforestation, damming of rivers, and wood removal along major waterways. I not only synthesize and link existing work on wood mobilization, transport and deposition to an intriguing case study, but challenge existing wood transport premises, provide new conceptual models describing processes of wood transport through drainage networks, and present new approaches and methods for quantifying and analyzing the variability in wood flux and influence of wood deposits on landforms. My descriptions of wood transport and shoreline processes prior to development of river corridors will be an invaluable resource to groups who seek to identify environmental impacts of dams and to scientists who are investigating the impact that past and future development of river corridors has had or will have on ecosystems

Phylogeographic Study of Apodemus ilex (Rodentia: Muridae) in Southwest China

BACKGROUND: The Mountains of southwest China have complex river systems and a profoundly complex topography and are among the most important biodiversity hotspots in the world. However, only a few studies have shed light on how the mountains and river valleys promote genetic diversity. Apodemus ilex is a fine model for investigating this subject. METHODOLOGY/PRINCIPAL FINDINGS: To assess the genetic diversity and biogeographic patterns of Apodemus ilex, the complete cytochrome b gene sequences (1,140 bp) were determined from 203 samples of A. draco/ilex that were collected from southwest China. The results obtained suggested that A. ilex and A. draco are sistergroups and diverged from each other approximately 2.25 million years ago. A. ilex could be divided into Eastern and Western phylogroups, each containing two sub-groups and being widespread in different geographical regions of the southern Hengduan Mountains and the western Yunnan - Guizhou Plateau. The population expansions of A. ilex were roughly from 0.089 Mya to 0.023 Mya. CONCLUSIONS: Our result suggested that A. ilex is a valid species rather than synonym of A. draco. As a middle-high elevation inhabitant, the phylogenetic pattern of A. ilex was strongly related to the complex geographical structures in southwest China, particularly the existence of deep river valley systems, such as the Mekong and Salween rivers. Also, it appears that the evolutionary history of A. ilex, such as lineage divergences and population expansions were strongly affected by climate fluctuation in the Late Pleistocene

EFFECTS OF FOREST MANAGEMENT PRACTICES ON RACCOON ECOLOGY IN A LONGLEAF PINE ECOSYSTEM

Raccoons (Procyon lotor) are ecological generalists common throughout a variety of habitats across their range. Although considered an economically important furbearer species in many regions, they are considered potentially important nest predators of certain species. Because raccoons may have a significant ecological impact on the landscape, it remains important to understand their ecology in a variety of ecosystems. We studied raccoon ecology in a longleaf pine ecosystem in southwestern Georgia, where little information for the species exists. Specifically, we assessed 269 daytime resting sites (i.e., refugia) associated with 31 radio-collared adult raccoons (18M, 13F) during 2014-2015 using an information theoretic approach. The top 2 predictive models included the variables tree diameter, tree type, presence of nearby hardwood, and distances to pine, hardwood, mixed forest and agriculture. However, tree type and diameter were the only informative variables, suggesting that for our study area, variables associated with the tree itself were more important than the landscape. Additionally, we evaluated raccoon home ranges and habitat selection on a study area in which longleaf pine forest restoration practices included substantial hardwood removal efforts spanning a 15-year time period (i.e. 1999 = pre-removal; 2015 = post-removal). Male raccoons maintained larger home ranges than females during both time periods, but there were no significant differences in home range size for either sex according to time period or the interaction. Raccoon habitat use differed by time period at 2 spatial scales. When selecting a home range (secondorder selection), mature pine forests were selected over all other habitat features before hardwood removal. Following hardwood removal, the only habitat selected differently was immature pine forest. When selecting habitats within the home range (third-order selection), hardwood forests were selected over all other habitat features before and after hardwood removal. Raccoons selected wetlands and primary roads differently following hardwood removal. Our findings suggest that habitat manipulation conducive to promoting longleaf pine restoration may impact raccoon populations by altering their space use

Integrative analyses of speciation and divergence in Psammodromus hispanicus (Squamata: Lacertidae)

BackgroundGenetic, phenotypic and ecological divergence within a lineage is the result of past and ongoing evolutionary processes, which lead ultimately to diversification and speciation. Integrative analyses allow linking diversification to geological, climatic, and ecological events, and thus disentangling the relative importance of different evolutionary drivers in generating and maintaining current species richness.ResultsHere, we use phylogenetic, phenotypic, geographic, and environmental data to investigate diversification in the Spanish sand racer (Psammodromus hispanicus). Phylogenetic, molecular clock dating, and phenotypic analyses show that P. hispanicus consists of three lineages. One lineage from Western Spain diverged 8.3 (2.9-14.7) Mya from the ancestor of Psammodromus hispanicus edwardsianus and P. hispanicus hispanicus Central lineage. The latter diverged 4.8 (1.5-8.7) Mya. Molecular clock dating, together with population genetic analyses, indicate that the three lineages experienced northward range expansions from southern Iberian refugia during Pleistocene glacial periods. Ecological niche modelling shows that suitable habitat of the Western lineage and P. h. edwardsianus overlap over vast areas, but that a barrier may hinder dispersal and genetic mixing of populations of both lineages. P. h. hispanicus Central lineage inhabits an ecological niche that overlaps marginally with the other two lineages.ConclusionsOur results provide evidence for divergence in allopatry and niche conservatism between the Western lineage and the ancestor of P. h. edwardsianus and P. h. hispanicus Central lineage, whereas they suggest that niche divergence is involved in the origin of the latter two lineages. Both processes were temporally separated and may be responsible for the here documented genetic and phenotypic diversity of P. hispanicus. The temporal pattern is in line with those proposed for other animal lineages. It suggests that geographic isolation and vicariance played an important role in the early diversification of the group, and that lineage diversification was further amplified through ecological divergence

Node-weighted Steiner tree and group Steiner tree in planar graphs

We improve the approximation ratios for two optimization problems in planar graphs. For node-weighted Steiner tree, a classical network-optimization problem, the best achievable approximation ratio in general graphs is Θ [theta] (logn), and nothing better was previously known for planar graphs. We give a constant-factor approximation for planar graphs. Our algorithm generalizes to allow as input any nontrivial minor-closed graph family, and also generalizes to address other optimization problems such as Steiner forest, prize-collecting Steiner tree, and network-formation games. The second problem we address is group Steiner tree: given a graph with edge weights and a collection of groups (subsets of nodes), find a minimum-weight connected subgraph that includes at least one node from each group. The best approximation ratio known in general graphs is O(log3 [superscript 3] n), or O(log2 [superscript 2] n) when the host graph is a tree. We obtain an O(log n polyloglog n) approximation algorithm for the special case where the graph is planar embedded and each group is the set of nodes on a face. We obtain the same approximation ratio for the minimum-weight tour that must visit each group

Power Aware Routing Protocol for MANETs Based on Swarm Algorithm

Creating any standard protocol having 2 or more QoS limitations might be described as an NP-complete. Swarm technology is used to solve such problem. Even so, to fix difficult problems using swarm algorithms, how many iterations essential is going to be proportional for you to problem complexity. In this a standard protocol is presented depending on hybrid swarm algorithm standard protocol. This protocol has higher bundle overheads which more often than not bring about devouring higher battery power. In the present work to reduce the higher battery power , power aware routing protocol is developed based on Swarm algorithm

Biological control of the chestnut gall wasp with \emph{T. sinensis}: a mathematical model

The Asian chestnut gall wasp \emph{Dryocosmus kuriphilus}, native of China, has become a pest when it appeared in Japan, Korea, and the United States. In Europe it was first found in Italy, in 2002. In 1982 the host-specific parasitoid \emph{Torymus sinensis} was introduced in Japan, in an attempt to achieve a biological control of the pest. After an apparent initial success, the two species seem to have locked in predator-prey cycles of decadal length. We have developed a spatially explicit mathematical model that describes the seasonal time evolution of the adult insect populations, and the competition for finding egg deposition sites. In a spatially homogeneous situation the model reduces to an iterated map for the egg density of the two species. While the map would suggest, for realistic parameters, that both species should become locally extinct (somewhat corroborating the hypothesis of biological control), the full model, for the same parameters, shows that the introduction of \emph{T. sinensis} sparks a traveling wave of the parasitoid population that destroys the pest on its passage. Depending on the value of the diffusion coefficients of the two species, the pest can later be able to re-colonize the empty area left behind the wave. When this occurs the two populations do not seem to attain a state of spatial homogeneity, but produce an ever-changing pattern of traveling waves