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Articles 2491 - 2520 of 6306

Full-Text Articles in Terrestrial and Aquatic Ecology

Freshwater And Marine Survival Of Coho Salmon (Oncorhynchus Kisutch) As A Function Of Juvenile Life History, Grace Katherine Ghrist Jan 2019

Freshwater And Marine Survival Of Coho Salmon (Oncorhynchus Kisutch) As A Function Of Juvenile Life History, Grace Katherine Ghrist

Cal Poly Humboldt theses and projects

Juvenile Coho Salmon (Oncorhynchus kisutch) in coastal California streams exhibit various life history strategies during their freshwater development. One strategy of interest to managers and conservationists is the early migrant. Juvenile early migrants emigrate from natal habitat into lower parts of the watershed or estuary during their first fall or winter, where they rear before migration to the ocean. By contrast, the more prevalent spring migrant resides in natal reaches over the winter and migrates directly to the ocean the following spring. Salmon monitoring programs generally estimate juvenile production and demographic rates using only spring migrants, and these …


Effects Of Longline Oyster Aquaculture On Benthic Invertebrate Communities In Humboldt Bay, California, Hannah C. Coe Jan 2019

Effects Of Longline Oyster Aquaculture On Benthic Invertebrate Communities In Humboldt Bay, California, Hannah C. Coe

Cal Poly Humboldt theses and projects

Oyster aquaculture has had a commercial presence in Humboldt Bay for nearly 60 years and has experienced changes in scope and methodology as the industry has grown. The traditional method of bottom-culture oyster beds has been phased out, with longline oyster aquaculture becoming the common replacement. However, this transition has preceded much of the research regarding potential impacts to the broader ecosystem. The benthic invertebrate community of Humboldt Bay is a vital food source for many commercially important fishes, as well as for the many shorebirds that utilize Humboldt Bay. The importance of the invertebrate community to the ecosystem highlights …


Using Environmental Dna And Occupancy Modeling To Estimate Rangewide Metapopulation Dynamics Of The Endangered Tidewater Goby Eucyclogobius Spp., Chad M. Martel Jan 2019

Using Environmental Dna And Occupancy Modeling To Estimate Rangewide Metapopulation Dynamics Of The Endangered Tidewater Goby Eucyclogobius Spp., Chad M. Martel

Cal Poly Humboldt theses and projects

Conservation of species is most effective when metapopulation dynamics are well understood and incorporated into management plans, allowing managers to target conservation efforts where they will be most effective. The development of environmental DNA (eDNA) methods provides an efficient and highly sensitive approach to generate presence and absence data needed to elucidate metapopulation dynamics. Combining sample detection histories from eDNA surveys with occupancy models that account for non-detection can offer unbiased estimates of rangewide metapopulation dynamics. However, traditional occupancy models do not allow direct evaluation of the drivers of site occupancy, extinction, and colonization. Herein, I utilize a novel dynamic …


Relationship Between Habitat And Barn Owl Prey Delivery Rate And Composition In A Napa Valley Vineyard Agroecosystem, Dane A. R. St. George Jan 2019

Relationship Between Habitat And Barn Owl Prey Delivery Rate And Composition In A Napa Valley Vineyard Agroecosystem, Dane A. R. St. George

Cal Poly Humboldt theses and projects

The provision of habitat for natural enemies of agricultural pests is common in integrated pest management approaches globally but has rarely been examined for vertebrate predators controlling vertebrate pests. To mitigate the economic and environmental costs of treating for rodent pests, winegrape producers in Napa Valley, California, have installed nest boxes to attract barn owls (Tyto alba) to their properties, but their effectiveness to control rodent pests in vineyards has not been thoroughly tested. A rigorous estimate of the number of rodents barn owls remove from the landscape is a necessary first step, and this study aimed to …


Effects Of Climate Variability: A Long-Term Perspective On Leaf Litter Processing In The Ogeechee River, Jose A. Sanchez Jan 2019

Effects Of Climate Variability: A Long-Term Perspective On Leaf Litter Processing In The Ogeechee River, Jose A. Sanchez

College of Graduate Studies: Theses & Dissertations

The Intergovernmental Panel for Climate Change (IPCC) predicts a rise in temperatures and changes to precipitation patterns for the 21st century. These changes are expected to lead to a higher frequency of extreme events such as drought and floods which lead to the alteration of the hydrology, communities, and processes of freshwater ecosystems. Leaf litter decomposition in stream ecosystems is an important component of the energy and nutrient cycle representing a food source for aquatic organisms. This has made it a tool for assessing long term responses to disturbance due to changes in the assemblage of macroinvertebrates that …


Conceptualizing Ecological Responses To Dam Removal: If You Remove It, What’S To Come?, J. Ryan Bellmore, G. R. Press, Jeffrey J. Duda, Jim E. O'Connor, Amy E. East, Melissa M. Foley, Andrew C. Wilcox, Jon J. Major, Patrick Shafroth, Sarah A. Morley, Christopher S. Magirl, Chauncey W. Anderson, James E. Evans, Laura Shawn Craig Jan 2019

Conceptualizing Ecological Responses To Dam Removal: If You Remove It, What’S To Come?, J. Ryan Bellmore, G. R. Press, Jeffrey J. Duda, Jim E. O'Connor, Amy E. East, Melissa M. Foley, Andrew C. Wilcox, Jon J. Major, Patrick Shafroth, Sarah A. Morley, Christopher S. Magirl, Chauncey W. Anderson, James E. Evans, Laura Shawn Craig

School of Earth, Environment and Society Faculty Publications

One of the desired outcomes of dam decommissioning and removal is the recovery of aquatic and riparian ecosystems. To investigate this common objective, we synthesized information from empirical studies and ecological theory into conceptual models that depict key physical and biological links driving ecological responses to removing dams. We define models for three distinct spatial domains: upstream of the former reservoir, within the reservoir, and downstream of the removed dam. Emerging from these models are response trajectories that clarify potential pathways of ecological transitions in each domain. We illustrate that the responses are controlled by multiple causal pathways and feedback …


Variability In Microphytobenthos Biomass And Carbon Isotopic Values In Shallow Coastal Waters Of The Northern Gulf Of Mexico, Sharil N. Deleon, Jeffrey W. Krause, Ronald Baker Jan 2019

Variability In Microphytobenthos Biomass And Carbon Isotopic Values In Shallow Coastal Waters Of The Northern Gulf Of Mexico, Sharil N. Deleon, Jeffrey W. Krause, Ronald Baker

Gulf and Caribbean Research

No abstract provided.


Ecological Benefits Of Watershed-Scale Restoration In Two Intensively Mined Cold- And Warm-Water Ecosystems, Rebecca Anne Long Jan 2019

Ecological Benefits Of Watershed-Scale Restoration In Two Intensively Mined Cold- And Warm-Water Ecosystems, Rebecca Anne Long

Graduate Theses, Dissertations, and Problem Reports (ETD)

Stream restoration projects are increasingly common. However, restoration projects that establish measurable goals, have pre- and post-restoration monitoring, and are implemented at the watershed scale are rare. We conducted a long-term (9-year) before-after-control-impact designed assessment of two watershed-scale acid mine drainage (AMD) remediation programs, one in a warm-water ecosystem and one in a cold-water ecosystem in West Virginia, USA. Restoration was strategically designed to recover biodiversity and improve the native fisheries by restoring chemically degraded water quality and re-establishing riverscape connectivity. We used analysis of variance to quantify responses in water chemistry, benthic macroinvertebrate communities, and fish community composition before …


Microplastic In Aquatic Food Webs: Museum Specimens And Ingestion Experiments Reveal Controls On Microplastic Ingestion By Freshwater Fish, Loren Hou Jan 2019

Microplastic In Aquatic Food Webs: Museum Specimens And Ingestion Experiments Reveal Controls On Microplastic Ingestion By Freshwater Fish, Loren Hou

Master's Theses

Plastic is pervasive in modern economies and ecosystems. Early research suggests freshwater fish commonly ingest microplastic (particles < 5 mm), which may influence fish digestive tissues, but no studies have examined historical patterns in microplastic consumption or rates of microplastic retention in fish. We measured microplastic in digestive tissue of specimens collected and preserved over the last century (Field Museum, Chicago). We selected Micropterus salmoides (largemouth bass), Notropis stramineus (sand shiner), Ictalurus punctatus (channel catfish), and Neogobius melanostomus (round goby) because each was well represented in the museum collection, with specimens from urban rivers. Specimens from 1900-2018 showed increases in microplastic concentration from the 1950's to present. in a second project, we collected round gobies from Lake Michigan in Chicago to conduct feeding experiments to measure microplastic ingestion and retention rates. the majority of microplastic was excreted within 72 hours of ingestion. Results will aid in understanding ecological interactions of microplastic and freshwater fish, informing further work on the movement of microplastic in aquatic food webs.


Nutrient Uptake Among Urban And Non-Urban Streams Within The Piedmont Physiographic Province Of Virginia, Joseph T. Famularo Jan 2019

Nutrient Uptake Among Urban And Non-Urban Streams Within The Piedmont Physiographic Province Of Virginia, Joseph T. Famularo

Theses and Dissertations

To assess how urbanization impacts stream nutrient uptake, a series of instantaneous (i.e. slug) nutrient additions were conducted in 3 urban and 3 non-urban streams during open and closed canopy conditions. Single additions of N, P, and combined additions of N and P were performed at each site. These data were used to test the hypothesis that high N:P concentrations in urban streams would result in P-limited conditions, and to assess differences in nutrient uptake kinetics (i.e., the relationship between uptake and concentration) between urban and non-urban streams. The results show that there were no consistent differences in N vs. …


Assessment Of Microbial Carbon Processing And Its Implications To The Carbon Budget Of Lake Superior, Lindsey Michelle Koren Jan 2019

Assessment Of Microbial Carbon Processing And Its Implications To The Carbon Budget Of Lake Superior, Lindsey Michelle Koren

Theses and Dissertations

Over the past few decades, there has been increased research focus on carbon cycling within aquatic systems, especially with the changing global climate. Inland waters play a major role in the global carbon cycle, but the fundamental features remain poorly understood, particularly the large lakes of the world. Our experimental approach assessing the carbon budget of Lake Superior, the largest freshwater lake by area, provides spatial and temporal variability that has been previously overlooked but may be critical to our understanding on the biogeochemical processes controlling the lake. Multiple stations were chosen across the lake, both nearshore and offshore, to …


Colloidal And Truly Dissolved Metal(Loid)S In Wastewater Lagoons And Their Removal With Floating Treatment Wetlands, Lauren Sullivan Jan 2019

Colloidal And Truly Dissolved Metal(Loid)S In Wastewater Lagoons And Their Removal With Floating Treatment Wetlands, Lauren Sullivan

Graduate Student Theses, Dissertations, & Professional Papers

Climate change is predicted to cause continuing declines in late-season streamflow, thus increasing the relative contribution of wastewater effluent to surface water flows. Wastewater effluent represents a critical point source of metal and metalloid contamination to aquatic ecosystems and wastewater lagoons are the most common wastewater treatment system in the rural United States. Although the fraction of total wastewater metals and metalloids in "dissolved" forms (defined here asnm) likely drives the potential for negative effects on receiving waters, this broad operational definition lumps truly dissolved solutes (nm) with small colloids and nanomaterials (1-450 nm; hereafter colloids). This size distinction may …


Population Dynamics And Control Of Exotic South African Oryx In The Chihuahuan Desert, South-Central New Mexico, Louis Bender, Patrick Morrow, Mara Weisenberger, Bryce Krueger Jan 2019

Population Dynamics And Control Of Exotic South African Oryx In The Chihuahuan Desert, South-Central New Mexico, Louis Bender, Patrick Morrow, Mara Weisenberger, Bryce Krueger

Human–Wildlife Interactions

Introductions of exotic species can benefit certain publics but can also have many unanticipated consequences. South African oryx (Oryx gazella gazella) were introduced into the Chihuahuan Desert on White Sands Missile Range (WSMR), New Mexico, USA to alleviate a perceived lack of large mammal hunting opportunities. Because of conflicts with oryx as the population increased, we modeled population growth and determined survival of radio-collared oryx to identify rates of population increase, limiting factors to population growth, and levels of harvest necessary to control population growth. Following introductions in 1969–1977, oryx significantly increased their range and showed a rate …


Who Takes The Bait? Non-Target Species Use Of Bear Hunter Bait Sites, Ellen M. Candler, William J. Severud, Joseph K. Bump Jan 2019

Who Takes The Bait? Non-Target Species Use Of Bear Hunter Bait Sites, Ellen M. Candler, William J. Severud, Joseph K. Bump

Human–Wildlife Interactions

Hunting bears (Ursus spp.) over baits is legal in many countries, states, and provinces, but the practice remains a controversial topic among wildlife managers, hunting groups, and the general public. The baits used to attract bears may also provide a pulsed resource on the landscape that can be used by other wildlife species, particularly carnivores. To determine what other species might use bear bait sites, we constructed and monitored 21 bear bait sites with camera traps from August to October 2016 in the western Upper Peninsula of Michigan, USA. The sites mimicked typical American black bear (U. americanus …


Comparing Live-Capture Methods For Nutria: Single- Versus Multiple-Capture Cage Traps, Trevor R. Sheffels, Jacoby Carter, Mark D. Sytsma, Jimmy D. Taylor Jan 2019

Comparing Live-Capture Methods For Nutria: Single- Versus Multiple-Capture Cage Traps, Trevor R. Sheffels, Jacoby Carter, Mark D. Sytsma, Jimmy D. Taylor

Human–Wildlife Interactions

Herbivory and burrowing by nutria (Myocastor coypus) cause substantial ecological and economic damage. Trapping is a common, effective practice for reducing nutria damage; however, trapping approaches must continually be adapted to keep pace with evolving animal welfare and ethical issues and to more effectively target pest species of interest. Our objective was to evaluate the efficacy of 2 nonlethal trap types for nutria: single-capture (SCT) and multi-capture (MCT) cage traps. We established 3 MCTs and 3 SCTs at each of 7 sites on a 10,500-ha mixed-use island located 15 km northwest of Portland, Oregon, USA. We pre-baited using …


Comparison Of Conservation Policy Benefits For An Umbrella And Related Sagebrush-Obligate Species, Jonathan B. Dinkins, Jeffrey L. Beck Jan 2019

Comparison Of Conservation Policy Benefits For An Umbrella And Related Sagebrush-Obligate Species, Jonathan B. Dinkins, Jeffrey L. Beck

Human–Wildlife Interactions

Many conservation strategies promote the potential of multiple species benefitting from protection of large areas necessary for the continued viability of 1 species. One prominent strategy in western North America is Wyoming’s Sage-grouse Core Area Policy, which was designed to conserve greater sage-grouse (Centrocercus urophasianus; hereafter, sage-grouse) breeding habitat, but may also serve as an umbrella to conserve other sagebrush (Artemisia spp.)-obligate wildlife, including songbirds. Sagebrush-obligate songbirds and sage-grouse have undergone population declines throughout the western United States attributed to similar habitat issues. We compared trends of sagebrush-obligate songbirds from the Breeding Bird Survey and sage-grouse lek …


Justice For Nature, Haydn Washington Jan 2019

Justice For Nature, Haydn Washington

Animal Sentience

Eight points are made in this commentary: (1) Ecocentrism is the preferable term. (2) Indigenous societies have long used a kinship ethics. (3) Earth jurisprudence and ecodemocracy should be considered. (4) Assumptions can be better defined. (5) Ethical pluralism is open to question. (6) The ethics of individuals vs. ecosystems needs further discussion. (7) Including justice for nature within social justice may be a serious mistake. (8) Trustees need to be ethically sophisticated.


Just Preservation, Adrian Treves, Francisco J. Santiago-Ávila, William S. Lynn Jan 2019

Just Preservation, Adrian Treves, Francisco J. Santiago-Ávila, William S. Lynn

Animal Sentience

We are failing to protect the biosphere. Novel views of conservation, preservation, and sustainability are surfacing in the wake of consensus about our failures to prevent extinction or slow climate change. We argue that the interests and well-being of non-humans, youth, and future generations of both human and non-human beings (futurity) have too long been ignored in consensus-based, anthropocentric conservation. Consensus-based stakeholder-driven processes disadvantage those absent or without a voice and allow current adult humans and narrow, exploitative interests to dominate decisions about the use of nature over its preservation for futurity of all life. We propose that authentically non-anthropocentric …


Granting Political Representation To Non-Humans, Joe Gray Jan 2019

Granting Political Representation To Non-Humans, Joe Gray

Animal Sentience

This commentary discusses the representation of individuals versus populations — human and nonhuman, present and future — in Treves et al.’s proposed trusteeship for futurity. Terminological questions are also discussed.


To Preserve Or To Conserve?, Liv Baker Jan 2019

To Preserve Or To Conserve?, Liv Baker

Animal Sentience

Treves et al. propose the notion of trusteeship to help meet our responsibility to nature and individual animals, their homes, cultures, and societies. This proposal is grounded in a real-world framework that reveals how conservation has become distorted by anthropocentrism, human exceptionalism, and ethical hypocrisy.


Just Reductionism: In Defense Of Holistic Conservation, Bradley J. Bergstrom Jan 2019

Just Reductionism: In Defense Of Holistic Conservation, Bradley J. Bergstrom

Animal Sentience

Treves et al. (2019) argue that individual organisms should be protected by the courts. This already happens in many countries for rare and endangered species and for symbolically important species (e.g., raptors, songbirds, and bats in the U.S.), and through the international treaty for whales. But protection of these individuals stems from a focus on preserving their populations, whereas hunting of individuals is still a culturally accepted practice. Killing of individuals should be limited to valid reasons (e.g., eating the meat) and covered by fair-chase and humane-killing laws (which is not always the case). But “futurity” will not inherit present-day …


Just Preservation And The Half-Earth View, Helen Kopnina Jan 2019

Just Preservation And The Half-Earth View, Helen Kopnina

Animal Sentience

For interspecies justice, animal welfare, and animal rights, the planet needs to be divided on the basis of species' natural resource requirements. The Half-Earth View is that to maintain viable populations of the Earth's remaining species, half of landscapes and seascapes need protection from intensive economic activity. This protection is needed outside the nature preserve system, such as in agricultural areas or cities, so nature can co-exist with local communities.


Protecting Patients Who Lack A Voice, Rainer Spiegel Jan 2019

Protecting Patients Who Lack A Voice, Rainer Spiegel

Animal Sentience

Neither human young today nor future human generations nor non-human species have a voice in protecting the biosphere. Treves et al. propose courts and trustees for defending their interests. I describe an analogy with attempts to represent the interests of children and comatose patients in medicine.


Human Interests, Helen Tiffin Jan 2019

Human Interests, Helen Tiffin

Animal Sentience

Treves et al.’s proposal is welcome, but it will have to face at least four challenges: the interconnectedness of the human and the nonhuman portions of the biosphere, conflicts of interest, human overpopulation, and capitalism itself.


The Intrinsic Value Of Nature, Joanna E. Lambert Jan 2019

The Intrinsic Value Of Nature, Joanna E. Lambert

Animal Sentience

Treves et al. explain the need to preserve the rights of nonhuman species, human youth, and future generations. Although conservation biology has claimed to have an intrinsic valuation ethic since its inception in the 1980s, many aspects of the field have taken a decidedly anthropocentric and instrumentalist trajectory. This has important consequences for conservation-related policy and practice at all scales: local, regional, and global.


What Is In An Octopus's Mind?, Jennifer Mather Jan 2019

What Is In An Octopus's Mind?, Jennifer Mather

Animal Sentience

It is difficult to imagine what an animal as different from us as the octopus ‘thinks’, but we can make some progress. In the Umwelt or perceptual world of an octopus, what the lateralized monocular eyes perceive is not color but the plane of polarization of light. Information is processed by a bilateral brain but manipulation is done by a radially symmetrical set of eight arms. Octopuses do not self-monitor by vision. Their skin pattern system, used for excellent camouflage, is open loop. The output of the motor system of the eight arms is organized at several levels — brain, …


Octopus Umwelt Or Umwelten?, Luis H. Favela Jan 2019

Octopus Umwelt Or Umwelten?, Luis H. Favela

Animal Sentience

Even if its intelligent behaviors are the product of decentralized control systems, Mather argues that the octopus has an “Umwelt,” and, thus, a mind. I argue that Umwelt does not provide a conceptual basis for understanding the octopus as having a mind. First, Umwelt does not refer only to an organism’s perceptual abilities. Second, in providing evidence for decentralized control systems that underlie intelligent behaviors, Mather makes a case against an octopus Umwelt. Instead, the octopus is more akin to a collection of systems, or Umwelten, than a single system with an Umwelt.


A Community Of Minds, Bennett L. Schwartz Jan 2019

A Community Of Minds, Bennett L. Schwartz

Animal Sentience

Mather (2019) provides an excellent overview of the literature on octopus perception, cognition, memory, and behavior. Anyone interested in cephalopod cognition and brain organization will find her target article informative and interesting. In this commentary, I challenge the idea that an individual organism must have an individual mind. Given the structure of the octopus brain and their complex behavior, one must consider the possibility that an octopus is a community of minds rather than a single mind.


Octopi-Ing A Unique Niche In Comparative Psychology, Jennifer Vonk Jan 2019

Octopi-Ing A Unique Niche In Comparative Psychology, Jennifer Vonk

Animal Sentience

Mather’s work has been fundamental in informing scientists of the relatively mysterious behavior and cognition of an understudied group of animals – the cephalopods. This work helps to fill a gap in the comparative literature that has historically sought evidence for complex behavior only in species that are closely related to humans or share important ecological features such as social complexity.


What Is Good For An Octopus?, Heather Browning Jan 2019

What Is Good For An Octopus?, Heather Browning

Animal Sentience

Mather (2019) has brought together the current empirical research in support of the claim that octopuses possess minds; and the weight of the evidence does appear to support octopus sentience. Being sentient means an organism has welfare concerns, a subjective experience of life that can go well or poorly. Protecting welfare requires knowing what conditions will have a positive or negative impact. Understanding what is in the mind of an octopus will give us valuable insight into what is good for an octopus.