Digital Commons Network^™

Wetland Biogeochemical Responses To Predicted Climate Change Scenarios, Angela R. Shaffer

College of Graduate Studies: Theses & Dissertations

Wetlands are one of the world's largest known carbon sinks while comprising only a small amount of the Earth's surface. However, the amount of carbon sequestered by wetlands is shrinking as droughts and human disturbance increases. Carbon in wetlands is stored through the contrast of decomposition and sedimentation of organic matter and absorption of CO₂ from the atmosphere by soil microbes. Understanding how changing hydrological regimes and increased wildfires will affect wetland soil and microbial processes is important in the face of predicted climate change for future wetland conservation practices. Specifically, I seek to understand the response of southeastern …

Applied Cognition Research To Improve Sheep Welfare, Kristina Horback

Animal Sentience

If a change is going to occur in the care and management of domestic sheep, there needs to be a collaborative effort across many disciplines. This review by Marino & Merskin of the literature on cognitive processing in domestic sheep is limited by the inherent bias of the authors, including the impracticable goal of eliminating sheep production. Animal welfare concerns about the management of commercial sheep are valid; however, in order to make a difference, we need to develop an application for this knowledge about cognitive abilities in sheep.

Animal Sentience Is Not Enough To Motivate Conservation, Irene M. Pepperberg

Animal Sentience

Chapman & Huffman suggest that humans’ views of their own superiority are a source of their callousness toward the environment. I do not disagree but point to a number of other issues that must be addressed for conservation efforts to succeed.

Ecological Consequences Of Sea Star Wasting Disease: Non-Consumptive Effects And Trait-Mediated Indirect Interactions From Pisaster Ochraceus, Timothy Ian Mcclure

Cal Poly Humboldt theses and projects

Consumptive effects (CEs) of predators are an important factor in structuring biological communities, but further work is needed to understand how the interaction between spatial and temporal differences in predator density affects non-consumptive effects (NCEs) on prey. NCEs can cause indirect effects on food resources, known as trait-mediated indirect interactions (TMIIs), and thus can also affect community structure. However, few studies have considered the relationships between spatial and temporal predator density variation and the strength of NCEs and TMIIs in the natural environment. The ochre star Pisaster ochraceus is common predator of the herbivorous black turban snail Tegula funebralis, imposing …

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 …

Shade Trees Preserve Avian Insectivore Biodiversity On Coffee Farms In A Warming Climate, Sarah L. Schooler

Cal Poly Humboldt theses and projects

Coffee is an important export in many developing countries, with a global annual trade value of $100 billion. Climate change is projected to drastically reduce the area where coffee is able to be grown. Shade trees may mitigate the effects of climate change through temperature regulation for coffee growth, temperature regulation for pest control, and increase in pest-eating bird diversity. The impact of shade on bird diversity and microclimate on coffee farms has been studied extensively in the Neotropics, but there is a dearth of research in the Paleotropics. I examined the local effects of shade on bird presence and …

Achromatic Plumage Patch Quality: Internal Organ And Skeletal Correlates In Aleutian Cackling Geese (Branta Hutchinsii Leucopareia), Matthew D. Delgado

Cal Poly Humboldt theses and projects

Sexual selection theory predicts unique plumage patches signaling quality or status evolve via mate-choice and competition for mates. A growing body of research supports evidence that achromatic plumage patches may act as honest indicators of quality. Irregularities in these patches are attributed to an individual’s phenotypic and genotypic quality as well as environmental wear and tear. Aleutian cackling geese (Branta hutchinsii leucopareia) display achromatic plumage patches on their heads and necks, which may signal information about an individual’s attributes. I tested the honest advertisement and status signaling hypotheses by determining whether size and irregularities in the transition between …

Estimating Space Sharing Between Seabird, Pinniped, And Human Use In The Northern California Coast, Claire Marie Nasr

Cal Poly Humboldt theses and projects

Rocky coastlines incur high impacts from human use, but these places are also essential habitat for marine wildlife including seabirds and pinnipeds (seals and sea lions). Marine wildlife use coastal rocks to breed, rest, and engage in social interaction and exhibit different habitat use during the breeding and non-breeding season. Peak timing of human use occurs in spring summer, coinciding with breeding seasons for colonial seabirds and gregarious pinnipeds. The high potential of spatial and temporal overlap between human and seabird use of rocky coastlines could lead to high risk of disturbance events. I investigated the relative risk of disturbance …

Life History Of The Coastal Tailed Frog (Ascaphus Truei) Across An Elevational Gradient, Adrian Daniel Macedo

Cal Poly Humboldt theses and projects

The life history of a species is described in terms of its growth, longevity, and reproduction. Unsurprisingly, life history traits are known to vary in many taxa across environmental gradients. In the case of amphibians, species at high elevations and latitudes tend to have shorter breeding seasons, shorter activity periods, longer larval periods, reach sexual maturity at older ages, and produce fewer and larger clutches per year.

The Coastal Tailed Frog (Ascaphus truei) is an ideal species for the study of geographic variation in life history because it ranges across most of the Pacific Northwest from northern California …

Drought And Coyotes Mediate The Relationship Between Mesopredators And Human Disturbance In California, Molly K. Parren

Cal Poly Humboldt theses and projects

Mesopredators in California are facing two major changes to their ecosystem: drought and the expansion of human disturbance. As a result, mesopredators are likely shifting their habitat use as well as their interspecies interactions to balance resource needs and risk-taking on the landscape. In response to severe drought, the California Department of Fish and Wildlife deployed 585 camera traps throughout the Mojave Desert and Central Valley documenting mammalian mesopredator presence in a drought year (2016) and a post-drought year (2017). The objectives of this study were to examine spatial patterns of mesopredator occurrence and co-occurrence with a dominant predator, the …

Autumn Roost Selection By Male Hoary Bats (Lasiurus Cinereus) In Northern California, Danielle (Skye) Salganek

Cal Poly Humboldt theses and projects

The hoary bat, Lasiurus cinereus, is a solitary bat that roosts in the foliage of trees throughout the western hemisphere. Roosts are subject to the ambient temperature of their surroundings, thus hoary bats undergo long-distance migrations between summer and winter ranges to avoid freezing temperatures. Habitat selection has been studied during the summer for maternal female hoary bats, but not during migration and winter. Autumn migration coincides with the hoary bat mating period and it has been proposed that male and female bats may rendezvous on migration paths. Individuals may select roosts in stopover locations that enhance fitness by providing …

Why Cod Don't Like To Sunbathe: Quantity And Quality In The Animal Kingdom, Christoph Jung

Animal Sentience

The difference between a cod and a lizard is not just a quantitative one. The recognition of qualitative differences between species does not imply a moral ranking. Our species’ special abilities to shape the earth mean we have a special responsibility for ensuring a liveable future for all organisms, human and non-human.

Diversity On Human Difference: Unanimity On Human Responsibility, Colin A. Chapman, Michael A. Huffman

Animal Sentience

Further commentaries on our original target article add important new points and expand our understanding of the differences between animals, particularly between non-human and human primates. But whether they affirm or deny that humans are unique, all commentators agree that our special abilities mean we should be taking responsibility for the care of nature and the plants and animals it supports. We ask: is humankind doing this?

Superior Or Inferior, Human Uniqueness Is Manifold, Scott Atran

Animal Sentience

Chapman & Huffman (C & H) contend that, as with all biological traits, there is evolutionary continuity underlying cognitive and social traits previously thought to be unique to humans. Yet C & H, like Darwin, appeal to a seemingly unique moral aptitude that enables humans to be kind to conspecific strangers and other species.

Population Health Of Spotted Salamanders (Ambystoma Maculatum) In Created Vernal Pools: An Integrative Approach, Alice R. Millikin

Graduate Theses, Dissertations, and Problem Reports (ETD)

Habitat creation is an important tool for conservation to counteract habitat loss and degradation. Vernal pools are susceptible to destruction due to limited detection, protection, and regulation. These wetlands provide fishless breeding habitat for many amphibian species including spotted salamanders (Ambystoma maculatum) in eastern North America. Determining whether created vernal pool habitat is successful is often determined by demographic data of colonizing populations. I suggest that hormone levels, population genetics, and disease prevalence can improve our understanding of population health in created habitat. The goal of this dissertation was to assess the health of spotted salamander larvae in …

On Neglected Taxa: Protostomes And The Evolution Of Myelination, Michaella P. Andrade, Charles Morphy D. Santos

Animal Sentience

Understanding the evolution of nervous and sensory systems in animals is key to understanding the distribution of animal sentience. However, the use of model organisms – mostly vertebrates, and especially mammals – often biases comparative analyses. Sneddon et al. (2018a,b) point out that using nonhuman animals as models helps us better understand the multifaceted aspects of animal pain and sentience. Several concerns need to be considered in dealing with model organisms. Here we discuss how models that are unrepresentative phylogenetically influence hypotheses about the evolution of the myelination in animals. Greater effort is needed to escape “vertebrate-centrism” in evolutionary research.

Sharing Emotions Builds Bridges Between Individuals And Between Species, Elisabetta Palagi

Animal Sentience

Many animal species express, perceive and share emotions. These abilities have been favoured by natural selection because they allow subjects to respond to various situations in an appropriate way, thus facilitating survival and increasing fitness. The same-face/same-emotion phenomenon is at the basis of sharing feelings and emotions. Recent studies show that this capacity is not unique to humans and that it plays an important role in creating cohesive societies in many different species.

Tiger Sharks Eat Songbirds: Reply, J. Marcus Drymon, K. Feldheim, A. M.V. Fournier, A. E. Jefferson, A. M. Kroetz, Sean P. Powers, E. A. Seubert

University Faculty and Staff Publications

In response to our recent paper (Drymon et al. 2019), Yosef (2019) questions the mechanism proposed to explain interactions between tiger sharks (Galeocerdo cuvier) and migratory songbirds, while offering an alternative mechanism based on a single observation. We appreciate the comments from Yosef and the opportunity to respond.

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, …

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.

The Perfecting Of The Octopus, Ila France Porcher

Animal Sentience

Cephalopods split away from the phylogenetic tree about half a billion years ago, and octopus evolution has been accelerated by an extremely low survival rate. This helps explain why this unusual animal presents qualities found in no other. It has a radially organized nervous system with a processing centre for each of its eight tentacles. Yet, although this might suggest that each tentacle has its own centre of consciousness, it remains just one animal, with one mouth to feed, and one life to lose, and it behaves as if it is centrally controlled. Its capacity for a range of intelligent …

‘Mind’ Is An Ill-Defined Concept: Considerations For Future Cephalopod Research, Alexandra Schnell, Giorgio Vallortigara

Animal Sentience

Scientific discussions about the ‘mind’ of an octopus are empirically vacuous and should be confined to folk psychology. This form of labelling is unhelpful for science and should be replaced by specific mechanistic accounts of behavior and associated neural structures, which are amenable to rigorous scientific investigation. Mather provides a detailed review of octopus behavior, but rather than making unquantifiable assumptions about what orchestrates octopus behavior, efforts should focus on investigating cognitive mechanisms that can be measured. In this commentary, we outline two lines of research that include quantifiable methods to facilitate a more robust understanding of cephalopod behaviors and …

The Octopus Mind And The Argument Against Farming It, Jennifer Jacquet, Becca Franks, Peter Godfrey-Smith

Animal Sentience

Mather is convincing about octopuses having ‘a controlling mind, motivated to gather information,’ but stops short of asking what having that mind means for octopus moral standing. One consequence of understanding the octopus mind should be a refusal to subject octopuses to mass production. Octopus farming is in an experimental phase and supported by various countries. We argue that it is unethical because of concerns about animal welfare as well as environmental impacts.

Pulling The Wool From Our Eyes, Jennifer Vonk

Animal Sentience

Marino & Merskin review evidence of the complexity of sheep cognition, concluding that researchers ought to feel sheepish about misrepresenting ovine cognitive capacities. However, the failure to situate the data in critical context risks pulling the wool over readers’ eyes.

Reflections On Sheep Rearing, Joyce D'Silva

Animal Sentience

Sheep rearing has an incredibly long history. Sometimes this alone can give credibility and status to a human practice. In the twenty-first century, it may be time to reassess our treatment of sheep and their place in nature. “Just because we’ve always done it” no longer has validity by itself. There are many other human practices which used to be accepted widely in certain societies and which we now may find abhorrent. With sheep intelligence now rightly regarded as an acceptable area of research within the academic community, it is a good time to reflect on our treatment of these …

Casting A Sheep’S Eye On Science, David M. Peña-Guzmán

Animal Sentience

Marino & Merskin review evidence that sheep are not just passive and reactive creatures. They have personalities that vary from individual to individual and endure over time. It follows that we must rethink what it means to study them scientifically.

Far More To Sheep Than Meets The Casual Eye, Bernard Rollin

Animal Sentience

Marino & Merskin’s survey of the cognitive and social capacities of sheep is an eye-opener about the individuality and emotionality of this most maligned of all farm animals. My own eyes had already been opened by an adopted orphaned lamb, so much more like a dog as a companion animal than the mindless robot I had been conditioned to expect. I am morally certain that Marino & Merskin’s survey will have a similar effect on readers open to changing their minds.

Sentient Animals Do Not Just Live In The Present, John Webster

Animal Sentience

Sheep are particularly well-equipped with the cognitive and emotional skills appropriate to their phenotype and natural environment. These include spatial memory, the benefits of safety in numbers, and the ability to recognise special individuals in large flocks by sight and by sound. Marino & Merskin’s target article reviews convincing evidence on whether sheep are more or less clever than other mammalian species. Sheep are very good at being sheep. But sentient animals do not just live in the present. Their emotional state is not simply dictated by events of the moment. If they learn, they can cope; if not, they …

Positive Sentience Is Underrated, Teya Brooks Pribac

Animal Sentience

My commentary focuses on two aspects of ovine (well-)being considered in the review: the developmental context and (un)fulfilled potentialities.

Using Sheep Psychology To Guide Sheep Policy, Ralph Adolphs

Animal Sentience

Marino & Merskin’s valuable review of the literature on sheep cognition shows how entrenched common views of these animals’ mental lives are disputed by the research literature. Yet the evidence they muster faces three challenges that their target article does not discuss: (1) the behavioral tasks are strongly anthropocentric; (2) neuroscientific data are absent; and (3) applications are not discussed. I touch on all three of these here.