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Articles 5911 - 5940 of 19760

Full-Text Articles in Ecology and Evolutionary Biology

Seagrass Blue Carbon Stocks And Sequestration Rates In The Colombian Caribbean, Oscar Serrano, Diana I. Gómez-López, Laura Sánchez-Valencia, Andres Acosta-Chaparro, Raul Navas-Camacho, Juan González-Corredor, Cristian Salinas, Pere Masque, Cesar A. Bernal, Núria Marbà Jan 2021

Seagrass Blue Carbon Stocks And Sequestration Rates In The Colombian Caribbean, Oscar Serrano, Diana I. Gómez-López, Laura Sánchez-Valencia, Andres Acosta-Chaparro, Raul Navas-Camacho, Juan González-Corredor, Cristian Salinas, Pere Masque, Cesar A. Bernal, Núria Marbà

Research outputs 2014 to 2021

Seagrass ecosystems rank amongst the most efficient natural carbon sinks on earth, sequestering CO2 through photosynthesis and storing organic carbon (Corg) underneath their soils for millennia and thereby, mitigating climate change. However, estimates of Corg stocks and accumulation rates in seagrass meadows (blue carbon) are restricted to few regions, and further information on spatial variability is required to derive robust global estimates. Here we studied soil Corg stocks and accumulation rates in seagrass meadows across the Colombian Caribbean. We estimated that Thalassia testudinum meadows store 241 ± 118 Mg Corg ha−1 (mean ± SD) in the top 1 m-thick soils, …

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Deep Ocean Metagenomes Provide Insight Into The Metabolic Architecture Of Bathypelagic Microbial Communities, Silvia G. Acinas, Pablo Sánchez, Guillem Salazar, Francisco M. Cornejo-Castillo, Marta Sebastián, Ramiro Logares, Marta Royo-Llonch, Lucas Paoli, Shinichi Sunagawa, Pascal Hingamp, Hiroyuki Ogata, Gipsi Lima-Mendez, Simon Roux, José M. González, Jesús M. Arrieta, Intikhab S. Alam, Allan Kamau, Chris Bowler, Jeroen Raes, Stéphane Pesant, Peer Bork, Susana Agustí, Takashi Gojobori, Dolors Vaqué, Matthew B. Sullivan, Carlos Pedrós-Alió, Ramon Massana, Carlos M. Duarte, Josep M. Gasol Jan 2021

Deep Ocean Metagenomes Provide Insight Into The Metabolic Architecture Of Bathypelagic Microbial Communities, Silvia G. Acinas, Pablo Sánchez, Guillem Salazar, Francisco M. Cornejo-Castillo, Marta Sebastián, Ramiro Logares, Marta Royo-Llonch, Lucas Paoli, Shinichi Sunagawa, Pascal Hingamp, Hiroyuki Ogata, Gipsi Lima-Mendez, Simon Roux, José M. González, Jesús M. Arrieta, Intikhab S. Alam, Allan Kamau, Chris Bowler, Jeroen Raes, Stéphane Pesant, Peer Bork, Susana Agustí, Takashi Gojobori, Dolors Vaqué, Matthew B. Sullivan, Carlos Pedrós-Alió, Ramon Massana, Carlos M. Duarte, Josep M. Gasol

Research outputs 2014 to 2021

The deep sea, the largest ocean’s compartment, drives planetary-scale biogeochemical cycling. Yet, the functional exploration of its microbial communities lags far behind other environments. Here we analyze 58 metagenomes from tropical and subtropical deep oceans to generate the Malaspina Gene Database. Free-living or particle-attached lifestyles drive functional differences in bathypelagic prokaryotic communities, regardless of their biogeography. Ammonia and CO oxidation pathways are enriched in the free-living microbial communities and dissimilatory nitrate reduction to ammonium and H2 oxidation pathways in the particle-attached, while the Calvin Benson-Bassham cycle is the most prevalent inorganic carbon fixation pathway in both size fractions. Reconstruction of …

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Factors Driving The Compositional Diversity Of Apis Mellifera Bee Venom From A Corymbia Calophylla (Marri) Ecosystem, Southwestern Australia, Daniela Scaccabarozzi, Kenneth Dods, Thao T. Le, Joel P. A. Gummer, Michele Lussu, Lynne Milne, Tristan Campbell, Ben Pan Wafujian, Colin Priddis Jan 2021

Factors Driving The Compositional Diversity Of Apis Mellifera Bee Venom From A Corymbia Calophylla (Marri) Ecosystem, Southwestern Australia, Daniela Scaccabarozzi, Kenneth Dods, Thao T. Le, Joel P. A. Gummer, Michele Lussu, Lynne Milne, Tristan Campbell, Ben Pan Wafujian, Colin Priddis

Research outputs 2014 to 2021

Bee venom (BV) is the most valuable product harvested from honeybees ($30 - $300 USD per gram) but marginally produced in apiculture. Though widely studied and used in alternative medicine, recent efforts in BV research have focused on its therapeutic and cosmetic applications, for the treatment of degenerative and infectious diseases. The protein and peptide composition of BV is integral to its bioactivity, yet little research has investigated the ecological factors influencing the qualitative and quantitative variations in the BV composition. Bee venom from Apis mellifera ligustica (Apidae), collected over one flowering season of Corymbia calophylla (Myrtaceae; marri) was characterized …

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Quantifying 210po/210pb Disequilibrium In Seawater: A Comparison Of Two Precipitation Methods With Differing Results, Montserrat Roca-Martí, Viena Puigcorbé, Maxi Castrillejo, Núria Casacuberta, Jordi Garcia-Orellana, J. Kirk Cochran, Pere Masqué Jan 2021

Quantifying 210po/210pb Disequilibrium In Seawater: A Comparison Of Two Precipitation Methods With Differing Results, Montserrat Roca-Martí, Viena Puigcorbé, Maxi Castrillejo, Núria Casacuberta, Jordi Garcia-Orellana, J. Kirk Cochran, Pere Masqué

Research outputs 2014 to 2021

The disequilibrium between lead-210 (210Pb) and polonium-210 (210Po) is increasingly used in oceanography to quantify particulate organic carbon (POC) export from the upper ocean. This proxy is based on the deficits of 210Po typically observed in the upper water column due to the preferential removal of 210Po relative to 210Pb by sinking particles. Yet, a number of studies have reported unexpected large 210Po deficits in the deep ocean indicating scavenging of 210Po despite its radioactive mean life of ∼ 200 days. Two precipitation methods, Fe(OH)3 and Co-APDC, are typically used to concentrate Pb and Po from seawater samples, and deep …

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What Lies Beneath: Predicting Seagrass Below-Ground Biomass From Above-Ground Biomass, Environmental Conditions And Seagrass Community Composition, C. J. Collier, L. M. Langlois, Kathryn M. Mcmahon, J. Udy, M. Rasheed, E. Lawrence, A. B. Carter, M. W. Fraser, L. J. Mckenzie Jan 2021

What Lies Beneath: Predicting Seagrass Below-Ground Biomass From Above-Ground Biomass, Environmental Conditions And Seagrass Community Composition, C. J. Collier, L. M. Langlois, Kathryn M. Mcmahon, J. Udy, M. Rasheed, E. Lawrence, A. B. Carter, M. W. Fraser, L. J. Mckenzie

Research outputs 2014 to 2021

© 2020 Seagrass condition, resilience and ecosystem services are affected by the below-ground tissues (BGr) but these are rarely monitored. In this study we compiled historical data across northern Australia to investigate biomass allocation strategies in 13 tropical seagrass species. There was sufficient data to undertake statistical analysis for five species: Cymodocea serrulata, Halophila ovalis, Halodule uninervis, Thalassia hemprichii, and Zostera muelleri. The response of below-ground biomass (BGr) to above-ground biomass (AGr) and other environmental and seagrass community composition predictor variables were assessed using Generalized Linear Models. Environmental data included: region, season, sediment type, water depth, proximity to land-based sources …

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Evidence Of Large Increases In Sedimentation Rates Due To Fish Trawling In Submarine Canyons Of The Gulf Of Palermo (Sw Mediterranean), Sarah Paradis, Claudio Lo Iacono, Pere Masqué, Pere Puig, Albert Palanques, Tommaso Russo, The Island Cruise Tem Jan 2021

Evidence Of Large Increases In Sedimentation Rates Due To Fish Trawling In Submarine Canyons Of The Gulf Of Palermo (Sw Mediterranean), Sarah Paradis, Claudio Lo Iacono, Pere Masqué, Pere Puig, Albert Palanques, Tommaso Russo, The Island Cruise Tem

Research outputs 2014 to 2021

Bottom trawling in submarine canyons can affect their natural sedimentation rates, but studies addressing this issue are still scarce. In the Gulf of Palermo (SW Mediterranean), bottom trawling occurs on the slope around Oreto, Arenella and Eleuterio canyons. Analyses of excess 210Pb concentrations and grain size fractions in sediment cores from their canyon axes revealed that sedimentation rates and silt contents increased in all canyons in the 1980s, due to the expansion of more powerful trawlers ( > 500 HP) to deeper fishing grounds. In Eleuterio and Arenella canyons, sedimentation rates increased by an order of magnitude (0.1-1.4 cm·yr-1), whereas they …

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Journal Of Ecology 2021 Global Rainfall-Seagrass Resilience-Swan River, Chanelle L. Webster, Kathryn M. Mcmahon, Paul S. Lavery, Simone Strydom, Marta Sánchez Alarcón, Kieryn L. Kilminster, Katherine Bennet, Sian Mcnamara Jan 2021

Journal Of Ecology 2021 Global Rainfall-Seagrass Resilience-Swan River, Chanelle L. Webster, Kathryn M. Mcmahon, Paul S. Lavery, Simone Strydom, Marta Sánchez Alarcón, Kieryn L. Kilminster, Katherine Bennet, Sian Mcnamara

Research Datasets

The excel file contains: summary of daily maximum precipitation from global rainfall analysis, monthly change in seagrass indicators (biomass, leaf density etc); water quality data including salinity, temperature and light data. There are also .nc files containing precipitation data from 1979-2019.

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Nitrogen Dynamics And Transport Along Flowpaths In A Rural Wetland-Stream Complex, Colton Kyro Jan 2021

Nitrogen Dynamics And Transport Along Flowpaths In A Rural Wetland-Stream Complex, Colton Kyro

Graduate Student Theses, Dissertations, & Professional Papers

Human activities have doubled the rate of nitrogen inputs onto the landscape resulting in elevated nitrogen concentrations in our streams. Anthropogenically applied nitrogen is largely transported to stream networks via groundwater movement. Groundwater discharge occurs in distinct points along a stream but whose influences can often persist far beyond that area due to insufficient biogeochemical removal of imported nitrogen potentially causing alterations in community structure and precipitating large algae blooms. To understand the factors governing nitrogen abundance in a historical polluted stream, I used a mass-balance approach to quantify groundwater-surface water interaction and the magnitude of groundwater nitrogen input and …

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Concentration And Composition Of Nanoparticles And Colloidal Particles In A Mine-Waste Contaminated River, Kaitlin Rose Perkins Jan 2021

Concentration And Composition Of Nanoparticles And Colloidal Particles In A Mine-Waste Contaminated River, Kaitlin Rose Perkins

Graduate Student Theses, Dissertations, & Professional Papers

Metals and metalloids (metal(loid)s) in aquatic ecosystems are often described through measures of their concentrations in whole and filtered waters. The filtered fraction is operationally defined as “dissolved,” and assumed to be primarily composed of free metal(loid) ions or of ions bound by low molecular weight organic matter. This definition ignores that the dissolved fraction also likely contains colloidal particles (1 to 1000 nm) that can pass through commonly used filters. This colloidal fraction can also be preferentially removed from the water column by algae and other aquatic organisms compared to free metal(loid) ions and organic bound metal(loid)s. Though they …

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Why Advertise In Hwi? Jan 2021

Why Advertise In Hwi?

Human–Wildlife Interactions

The benefits of advertising with Human–Wildlife Interactions and how to do so.

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Follow Us On Social Media Jan 2021

Follow Us On Social Media

Human–Wildlife Interactions

How to follow HWI on social media.

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In The News, Ike Ionel, Jessica Tegt Jan 2021

In The News, Ike Ionel, Jessica Tegt

Human–Wildlife Interactions

Items in the news.

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Common Raven Nesting And Spatial Distancing On Power Lines In Southeast Idaho, Usa, Quinn R. Shurtliff, Jericho C. Whiting Jan 2021

Common Raven Nesting And Spatial Distancing On Power Lines In Southeast Idaho, Usa, Quinn R. Shurtliff, Jericho C. Whiting

Human–Wildlife Interactions

Common raven (Corvus corax; raven) abundance and distribution have increased in western North America in recent decades, facilitated by anthropogenic subsidies and other environmental changes. Electrical power transmission line structures provide nesting substrates for ravens. When these structures transect landscapes where natural nest substrates are limited, they may facilitate raven predation on eggs and juveniles of sensitive avian and reptile species. Little information is available regarding raven nest density trends on adjacent power lines or how raven territorial behavior influences spatial partitioning of nests, and hence, nest density. This knowledge would be valuable for managers of sensitive prey …

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Occurrence, Resource Use, And Demography Of The Common Raven In North America: A Research Synthesis, William C. Webb, Peter S. Coates, Seth J. Dettenmaier, David J. Delehanty Jan 2021

Occurrence, Resource Use, And Demography Of The Common Raven In North America: A Research Synthesis, William C. Webb, Peter S. Coates, Seth J. Dettenmaier, David J. Delehanty

Human–Wildlife Interactions

We reviewed the scientific literature to inventory existing studies of common raven (Corvus corax; raven) ecology in western North America. We conducted an intial literature review between June 2015 and March 2018. Prior to completing our review, we revisited the published literature for any additional relevant studies in July 2021. Our goal was to identify knowledge gaps and to synthesize the current understanding of environmental features that may support raven populations that pose general threats to biodiversity and sensitive species in particular. We focused our review on studies with direct conservation applications related to 3 processes of raven …

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Common Raven Impacts On The Productivity Of A Small Breeding Population Of Snowy Plovers, Matthew J. Lau, Benjamin H. Becker, David T. Press Jan 2021

Common Raven Impacts On The Productivity Of A Small Breeding Population Of Snowy Plovers, Matthew J. Lau, Benjamin H. Becker, David T. Press

Human–Wildlife Interactions

Common ravens (ravens; Corvus corax), an adaptable, synanthropic generalist, have thrived coincident with increasing human landscape modifications and fragmentation, consequently affecting their prey, which are often sensitive native and protected species. Ravens are a conservation concern for the protected western snowy plover (plover; Charadrius nivosus nivosus), causing low nest and chick survival in some breeding areas along the Pacific coast of North America. We used a long-term dataset from a breeding snowy plover monitoring program in Point Reyes National Seashore (PRNS) to investigate potential impacts of ravens on snowy plover nest and fledging success. Between 2002 and 2020, …

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A Desert Tortoise–Common Raven Viable Conflict Threshold, Kerry L. Holcomb, Peter S. Coates, Brian G. Prochazka, Timothy Shields, William I. Boarman Jan 2021

A Desert Tortoise–Common Raven Viable Conflict Threshold, Kerry L. Holcomb, Peter S. Coates, Brian G. Prochazka, Timothy Shields, William I. Boarman

Human–Wildlife Interactions

Since 1966, common raven (Corvus corax; raven) abundance has increased throughout much of this species’ Holarctic distribution, fueled by an ever-expanding supply of anthropogenic resource subsidies (e.g., water, food, shelter, and nesting substrate) to ecoregion specific raven population carrying capacities. Consequently, ravens are implicated in declines of both avian and reptilian species of conservation concern, including the California (USA) endangered and federally threatened Mojave desert tortoise (Gopherus agassizii; desert tortoise). While ravens are a natural predator of desert tortoises, the inter-generational stability of desert tortoise populations is expected to be compromised as annual juvenile survival is …

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A Rapid Assessment Function To Estimate Common Raven Population Densities: Implications For Targeted Management, Brianne E. Brussee, Peter S. Coates, Shawn T. O'Neil, Seth J. Dettenmaier, Pat J. Jackson, Kristy B. Howe, David Delehanty Jan 2021

A Rapid Assessment Function To Estimate Common Raven Population Densities: Implications For Targeted Management, Brianne E. Brussee, Peter S. Coates, Shawn T. O'Neil, Seth J. Dettenmaier, Pat J. Jackson, Kristy B. Howe, David Delehanty

Human–Wildlife Interactions

Common raven (Corvus corax; raven) populations have increased over the past 5 decades within the western United States. Raven population increases have been largely attributed to growing resource subsidies from expansion of human enterprise. Concomitantly, managers are becoming increasingly concerned about elevated adverse effects on multiple sensitive prey species, damage to livestock and agriculture, and human safety. Managers could benefit from a rapid but reliable method to estimate raven densities across spatiotemporal scales to monitor raven populations more efficiently and inform targeted and adaptive management frameworks. However, obtaining estimates of raven density is data- and resource-intensive, which renders …

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A Novel Technique To Improve Capture Success Of Common Ravens, Lindsey R. Perry, Terrah M. Owens, Zachary T. Slick, Jimmy D. Taylor, Jonathan B. Dinkins Jan 2021

A Novel Technique To Improve Capture Success Of Common Ravens, Lindsey R. Perry, Terrah M. Owens, Zachary T. Slick, Jimmy D. Taylor, Jonathan B. Dinkins

Human–Wildlife Interactions

Traditional trapping techniques for common ravens (Corvus corax; raven) require significant effort, often produce low capture rates, and cannot be used in some situations. We designed a 3-m noose pole to secure ravens from nocturnal roost locations while using a strobe spotlight to temporarily disorient them. We collected measures of trapping efficiency and contrasted them with padded leghold traps also used in the study. We effectively implemented our noose pole method in July and August of 2018, 2019, and 2020 in the Baker and Cow Lakes sage-grouse (Centrocercus urophasianus) Priority Areas of Conservation in eastern Oregon, …

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Visual Marking Of Ground Nests Might Attract Corvids, Emily M. O'Donovan, Mark S. Boyce Jan 2021

Visual Marking Of Ground Nests Might Attract Corvids, Emily M. O'Donovan, Mark S. Boyce

Human–Wildlife Interactions

For ground-nesting birds such as waterfowl, estimating nest survival is a crucial step in assessing population dynamics, and marking nests facilitates continuous monitoring. A conventional method for marking ground nests is to use an inconspicuous rod at the nest bowl and a wooden lathe 10 m away. Nests are visually marked to allow for greater efficiency when revisiting nests and to facilitate subsequent nest searching sessions. Anecdotal evidence suggests that common ravens (Corvus corax) and American crows (C. brachyrhynchos) might learn to recognize these nest markers, resulting in artificially inflated rates of nest predation. In 2017 …

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Efficacy Of Manipulating Reproduction Of Common Ravens To Conserve Sensitive Prey Species: Three Case Studies, Corina A. Sanchez, Brianne E. Brussee, Peter S. Coates, Kerry L. Holcomb, Seth M. Harju, Timothy A. Shields, Mercy Vaughn, Brian G. Prochazka, Steven R. Mathews, Steffen Cornell, Chad V. Olson, David J. Delehanty Jan 2021

Efficacy Of Manipulating Reproduction Of Common Ravens To Conserve Sensitive Prey Species: Three Case Studies, Corina A. Sanchez, Brianne E. Brussee, Peter S. Coates, Kerry L. Holcomb, Seth M. Harju, Timothy A. Shields, Mercy Vaughn, Brian G. Prochazka, Steven R. Mathews, Steffen Cornell, Chad V. Olson, David J. Delehanty

Human–Wildlife Interactions

Expansion of human enterprise across western North America has resulted in an increase in availability of anthropogenic resource subsidies for generalist species. This has led to increases in generalists’ population numbers across landscapes that were previously less suitable for their current demographic rates. Of particular concern are growing populations of common ravens (Corvus corax; ravens), because predation by ravens is linked to population declines of sensitive species. Ecosystem managers seek management options for mitigating the adverse effects of raven predation where unsustainable predator–prey conflicts exist. We present 3 case studies examining how manipulating reproductive success of ravens influences …

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A Temporal Record Of Microplastic Pollution In Mediterranean Seagrass Soils, Martin Dahl, Sanne Bergman, Mats Björk, Elena Diaz-Almela, Maria Granberg, Martin Gullström, Carmen Leiva-Dueñas, Kerstin Magnusson, Candela Marco-Méndez, Nerea Piñeiro-Juncal, Miguel Ángel Mateo Jan 2021

A Temporal Record Of Microplastic Pollution In Mediterranean Seagrass Soils, Martin Dahl, Sanne Bergman, Mats Björk, Elena Diaz-Almela, Maria Granberg, Martin Gullström, Carmen Leiva-Dueñas, Kerstin Magnusson, Candela Marco-Méndez, Nerea Piñeiro-Juncal, Miguel Ángel Mateo

Research outputs 2014 to 2021

© 2021 Elsevier Ltd Plastic pollution is emerging as a potential threat to the marine environment. In the current study, we selected seagrass meadows, known to efficiently trap organic and inorganic particles, to investigate the concentrations and dynamics of microplastics in their soil. We assessed microplastic contamination and accumulation in 210Pb dated soil cores collected in Posidonia oceanica meadows at three locations along the Spanish Mediterranean coast, with two sites located in the Almería region (Agua Amarga and Roquetas) and one at Cabrera Island (Santa Maria). Almería is known for its intense agricultural industry with 30 000 ha of plastic-covered …

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Management And Conservation Of Westslope Cutthroat Trout In An Impacted, Connected River System, Troy Weant Smith Jan 2021

Management And Conservation Of Westslope Cutthroat Trout In An Impacted, Connected River System, Troy Weant Smith

Graduate Student Theses, Dissertations, & Professional Papers

Westslope cutthroat trout Oncorhynchus clarkii lewisi (WCT) is a native species of high conservation value that historically exhibited partially migratory behavior throughout its range. Long-term persistence of WCT is threatened by human habitat modification, fragmentation, introduction of non-native species, and hybridization. As a result of these changes, remnant populations in Montana have shifted toward resident populations in headwater systems and away from migratory populations in larger connected river networks. This is compounded by the historic introduction of rainbow trout O. mykiss (RBT) that hybridize with WCT, especially in larger river habitats. Rock Creek in western Montana, USA was historically managed …

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Monitoring The Wetland Landscape: White-Faced Ibis (Plegadis Chihi) Breeding Habitat As A Model Assemblage, Shea P. Coons Jan 2021

Monitoring The Wetland Landscape: White-Faced Ibis (Plegadis Chihi) Breeding Habitat As A Model Assemblage, Shea P. Coons

Graduate Student Theses, Dissertations, & Professional Papers

Wetlands structure landscape biodiversity by providing critical habitat to numerous fish and wildlife species. However, climate change, growing human populations, and shifting land use practices strain limited water supplies that sustain wetlands in the semi-arid western US. Conserving a wetland network with prominent value to wildlife is paramount to ensure future security of habitat and ecosystem processes. Here, I use white-faced ibis (Plegadis chihi; hereafter ‘ibis’) breeding colonies as a model system to identify and monitor a landscape-scale wetland network across the semi-arid western US. Ibis serve an important role in marking ecologically important wetland networks because they require a …

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A Reintroduction Retrospective: Comparative Fisher (Pekania Pennanti) Survival And Prey Habitat Use In The Cascade Mountains Of Washington State, Tanner S.T. Humphries Jan 2021

A Reintroduction Retrospective: Comparative Fisher (Pekania Pennanti) Survival And Prey Habitat Use In The Cascade Mountains Of Washington State, Tanner S.T. Humphries

Graduate Student Theses, Dissertations, & Professional Papers

Increasing human impacts on biodiversity highlight the global need for ecological restoration. For many wildlife species, reintroduction is necessary to re-establish populations in parts of their historic range where they have been extirpated. Reintroduction efforts are commonly used to help restore ecosystem integrity, but are often expensive, time consuming, and unsuccessful at generating self-sustaining populations. Thus, a more complete understanding of the factors affecting restoration success is important for ensuring successful outcomes and responsible stewardship. Fishers (Pekania pennanti) are one of the most commonly reintroduced carnivores in North America, but the success of such efforts is highly variable, …

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Noninvasive Genetic Sampling With A Bayesian Spatial Capture-Recapture Analysis To Estimate Abundance Of Roosevelt Elk (Cervus Canadensis Roosevelti), Makenzie Henk Jan 2021

Noninvasive Genetic Sampling With A Bayesian Spatial Capture-Recapture Analysis To Estimate Abundance Of Roosevelt Elk (Cervus Canadensis Roosevelti), Makenzie Henk

Cal Poly Humboldt theses and projects

Determining abundance of Roosevelt elk (Cervus canadensis roosevelti) in central Humboldt County, California has presented a unique challenge to wildlife managers due to the dense forest habitat and the animals’ elusive behavior. As the elk population has increased, so has human-wildlife conflict, and wildlife agencies need efficient and repeatable methods for determining abundance to inform management decisions. Traditional monitoring methods such as helicopter surveys are ineffective due to low sighting probability and strong behavioral responses to the aircraft. They also often lead to biased sex ratios when the distribution of males and females varies across the landscape. Non-invasive …

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Comparison Of Standard And Environmental Dna Methods For Estimating Chinook Salmon Smolt Abundance In The Klamath River, California, Doyle Joseph Coyne Jan 2021

Comparison Of Standard And Environmental Dna Methods For Estimating Chinook Salmon Smolt Abundance In The Klamath River, California, Doyle Joseph Coyne

Cal Poly Humboldt theses and projects

Evaluating abundance of juvenile salmonids is critical to conservation and management. Current abundance estimation involves use of rotary screw traps and mark-recapture studies. Use of environmental DNA (eDNA) in water samples offers a noninvasive and less expensive approach that may potentially improve or eventually replace traditional monitoring. Here I evaluate the utility of eDNA to predict weekly abundance estimates of outmigrating Chinook salmon (Oncorhynchus tshawytscha) smolts in the Klamath River, California. A total of 15 water samples were collected per week over the 17-week smolt outmigration in both 2019 and 2020. Chinook salmon eDNA concentration in each water …

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The Homology Of Sarcopterygian Gills, Kyle Orr Jan 2021

The Homology Of Sarcopterygian Gills, Kyle Orr

Cal Poly Humboldt theses and projects

Vertebrate gills may be either external (protruding from the body surface) or internal (enclosed in a chamber). Among living amphibians, external gills are found in salamander larvae and neotenes, early frog larvae, and caecilian embryos; internal gills are found only in later-stage frog larvae. Evidence for internal gills has also been found in stem tetrapods, and amphibian-like external gills have been found in some fossil temnospondyls and anthracosaurs. Gill homology among these groups and life stages has long been questioned. To address this, scanning electron microscopy, vascular casting, and paraffin sectioning were utilized to study the morphology of gills and …

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Seed Bank Composition Within Two Sagebrush Communities: A Comparison Of Drought, Microsite, And Aboveground Community Effects, Allison Marie Nunes Jan 2021

Seed Bank Composition Within Two Sagebrush Communities: A Comparison Of Drought, Microsite, And Aboveground Community Effects, Allison Marie Nunes

Cal Poly Humboldt theses and projects

Soil seed banks are critical biodiversity repositories for many dryland plant communities. Understanding how environmental factors alter seed bank composition can provide valuable information on ecological processes within a community and be useful for creating land management strategies. Using the seedling emergence method, I characterized the seed bank of two adjacent dryland plant communities that vary in dominant sagebrush species, structure, and function. Specifically, within an Artemisia arbuscula dominated community and Artemisia cana dominated community, I assessed the influence of three environmental factors on each seed bank: experimentally imposed drought, shrub microsites (compared to interspaces), and aboveground vegetation. Within the …

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Recreation, Vegetation Management, And Disease Impact Sympatric Carnivore Activity In California's East Bay Parks, Leigh J. Douglas Jan 2021

Recreation, Vegetation Management, And Disease Impact Sympatric Carnivore Activity In California's East Bay Parks, Leigh J. Douglas

Cal Poly Humboldt theses and projects

East Bay Regional Park District designated over 1000 ha of protected wildland-urban interface habitat in the hills of California’s East Bay Area for invasive tree removal to reduce fire risk and restore native habitat over a 10-year period starting in 2016. From June to November 2019, 36 camera traps were deployed using a stratified two-pronged detection approach of surveying recreation and wildlife trails to assess the impact of vegetation management on the spatiotemporal distribution of sympatric carnivore species while accounting for potential impacts of human activity and proximity to development. The sampling effort resulted in 5,191 cumulative trap nights, 2,739 …

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Evaluating Immaturity Risk In Young Stands Of The Serotinous Knobcone Pine (Pinus Attenuata), Katherine Marlin Jan 2021

Evaluating Immaturity Risk In Young Stands Of The Serotinous Knobcone Pine (Pinus Attenuata), Katherine Marlin

Cal Poly Humboldt theses and projects

As wildfire becomes increasingly frequent, many plant populations risk local extirpation if fire recurs too soon, a problem dubbed “immaturity risk”. We studied the regeneration of a serotinous conifer species, knobcone pine (Pinus attenuata), as a function of the time between high-severity fires (6-79 years). We evaluated age, cone production, and regeneration at two burned sites in northern California, the Ranch Fire (2018) in Mendocino National Forest, and the Carr Fire (2018) in Whiskeytown National Recreation Area. We found an average of 30.5 filled seeds in closed, brown cones (42% viability of filled seeds). The bulk of the …

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