California North Research Articles

Bad dog: feral and free-roaming dogs as agents of conflict

Domestic dogs are ubiquitous where humans reside. While typically considered a companion animal, their ability to thrive as feral and free-roaming animals often results in conflict with wildlife and is an impediment to conservation goals (Gompper, 2013). Home, Bhatnagar & Vanak (2018) provides evidence for this in India, illustrating the role of feral and free-roaming dogs as an invasive species with negative impacts on endemic wildlife, including threatened and endangered species. The authors found that the majority of wildlife attacks by dogs happen when dogs are not with people. It seems that this is the true canine conundrum: humans value dogs as companions, but the consequences are high for endemic wildlife when dogs do not have human companions. While the study used data from India, the impacts of feral and free-roaming dogs are found globally (Young et al., 2011; Hughes & MacDonald, 2013). Indeed, conflicts between wildlife and free-roaming feral dogs happen even when government ordinances and laws exist that forbid owners from allowing dogs to be free roaming. For example, in Arizona, where these types of laws exist, during 2017, USDA-APHIS-Wildlife Services (WS) reported the removal or transfer of custody for 125 feral and free-roaming dogs in response to human conflicts. This was more than double the next most common species reported: the coyote (Canis latrans). With the existence of similar laws, the WS program in California has assisted county-level governments with feral and free-roaming dogs preying on livestock that were suspect releases from illegal marijuana grows along California's north coast. Dogs, which many agency employees suspect to have crossed the California–Mexico border, have also been removed to protect threatened avian species, especially those nesting on beaches. These incidents are not rare or new. Fowler (1979) showed the impacts of dogs on beaches where green sea turtles (Chelonia mydas) nested which have since been reported globally for nearly all species of sea turtles. In WS data, reported in the past 10 years (2008–2017), these types of conflicts have resulted in the removal or transfer of custody for 340 feral and free-roaming dogs in California. In the USA, WS is often tasked with responding to conflicts with feral and free-roaming dogs that are reported, but local animal control agencies may also respond, so these data likely represent the minimum amount of dog conflict in these two states with more laws and ordinances regarding dogs than many other states. Home et al. (2018) show that the respondents would opt for trap-neuter release (TNR) or euthanasia to mitigate conflict, but the percentage of respondents even in these top two categories was low. The authors already note the lack of success with TNR programs. Euthanasia may more effectively remove the dogs causing conflicts, but negative perceptions by the public often surround euthanasia because of human associations with dogs as companion animals. Thus, the solution likely circles back to the conundrum – educating people about the importance of human companionship to dogs to reduce the number of dogs without human companions in the landscape. Survey participants in the study believed that the problem has grown in recent years. With burgeoning human populations, this is undoubtedly true throughout the range of domestic dogs, which is most of the planet's human-inhabited landmasses. Studies like this highlight the problems but also begin to build the foundation for how to resolve them. The challenge is to ensure solutions are employed when the species put at risk are still able to recover.

Deciphering the sexual diploid members of the Boechera suffrutescens complex (Brassicaceae, Boechereae).

Boechera is a model genus that is of particular interest for understanding apomixis due to the presence of numerous apomictic diploid lineages that are tightly correlated with hybridisation events. Boechera includes many narrowly distributed endemics and apomictic hybrid lineages that obscure morphological boundaries amongst taxa. In this study, we focus on the Boechera suffrutescens complex, a phylogenetically well-supported but taxonomically complex north-western United States clade whose diploid species currently include the widespread B. suffrutescens and two narrowly distributed serpentine endemics, B. constancei and B. rollei. Using a 15-locus microsatellite dataset, we infer ploidy and sexual vs. apomictic reproduction for all individuals and then assess species limits for all sexual diploid samples. Our results support the recognition of B. rollei and B. constancei as distinct species and reveal three divergent sexual diploid lineages within B. suffrutescens sensu lato. The latter three lineages exhibit geographic, genetic and morphological coherence and consequently warrant recognition at the species rank. These include Boechera suffrutescens s.s., which is restricted to Idaho and eastern Oregon, Boechera botulifructa, a newly described species distributed along the Cascade Mountain Province from Lassen County, California north to Deschutes County, Oregon and the heretofore dismissed species Boechera duriuscula (basionym ≡ Arabis duriuscula), which occurs along the Sierra Nevada Province from Plumas County southwards to Fresno County, California. Our data also reveal substructure in B. constancei that is likely attributable to the highly fragmented distribution of its serpentine habitat. This refined taxonomic framework for the B. suffrutescens complex enhances Boechera as a model system, adds to our knowledge of speciation in edaphically extreme environments and provides information on ongoing conservation efforts for these taxa.

It's a trust thing: Assessing fishermen's perceptions of the California North Coast marine protected area network

The California's Marine Life Protection Act (MLPA) is a recent high-profile initiative that led to the implementation of a network of 124 marine protected areas (MPAs) encompassing 16% of state waters. The effort was conducted through six different regional processes that incorporated stakeholder and scientific involvement, ending with the North Coast region. While the initiative has been described as a success in terms of implementation, there has been relatively little empirical research about social perceptions of the MPA network in order to examine whether stakeholders view the effort as successful. Our research team conducted surveys with 178 commercial and charter fishermen and held five focus groups in each of the major ports of the region in order to assess fishermen's perceptions of the California North Coast MPA network – including perceptions of both the process of implementation and potential outcomes from the network. Among fishermen, satisfaction with the overall process was low; however, the level of satisfaction with the inclusion of local input and the final location of the MPAs was more evenly divided. Levels of trust in management entities, including those who implemented the MPA network, were low. Additionally, in focus group discussions, fishermen described several perceived shortcomings of the process, including an overall “top-down” approach, a failure to consider the local context, and the appearance of being dismissive of fishermen's perspectives. In terms of outcomes, fishermen overwhelmingly did not believe that the MPA network would improve ocean health or their income from fishing. Qualitatively, fishermen reported that while they were experiencing some minor adverse effects from the MPA network, overall they did not believe that socioeconomic impacts on the fishing industry from the MPA network would be substantial. Many expressed relief that the location of MPAs avoided many important fishing grounds. Trust emerged as an important variable. For example, the reported level of trust by fishermen in the entity that implemented the MPA network had a statistically significant correlation with their level of satisfaction with the overall process, including the final location of the MPA network. Findings complicate initial assessments of the MLPA implementation process as an overall success, and highlight the importance of trust to building successful and lasting marine conservation initiatives.

Abstracts From the 2017 Annual Meeting of the Society For Northwestern Vertebrate Biology, Held Jointly With the California North Coast Chapter of the Wildlife Society, and Northwest Partners In Amphibian and Reptile Conservation, At Blue Lake Casino And Hotel, Blue Lake, California, 28 February–3 March 2017

Abstracts From the 2017 Annual Meeting of the Society For Northwestern Vertebrate Biology, Held Jointly With the California North Coast Chapter of the Wildlife Society, and Northwest Partners In Amphibian and Reptile Conservation, At Blue Lake Casino And Hotel, Blue Lake, California, 28 February–3 March 2017

Getting to the bottom of fishery interactions with living habitats: spatiotemporal trends in disturbance of corals and sponges on the US west coast

MEPS Marine Ecology Progress Series Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsTheme Sections MEPS 574:29-47 (2017) - DOI: https://doi.org/10.3354/meps12195 Getting to the bottom of fishery interactions with living habitats: spatiotemporal trends in disturbance of corals and sponges on the US west coast Lewis A. K. Barnett1,*, Shannon M. Hennessey2, Timothy E. Essington2, Andrew O. Shelton3, Blake E. Feist3, Trevor A. Branch2, Michelle M. McClure4 1School of Aquatic & Fishery Sciences, University of Washington, Seattle, WA 98195, USA; under contract to Fishery Resource Analysis and Monitoring Division, Northwest Fisheries Science Center, NOAA, Seattle, WA 98112, USA 2School of Aquatic and Fishery Sciences, University of Washington, Seattle, WA 98195, USA 3Conservation Biology Division, Northwest Fisheries Science Center, National Marine Fisheries Service, NOAA, Seattle, WA 98112, USA 4Fishery Resource Analysis and Monitoring Division, Northwest Fisheries Science Center, National Marine Fisheries Service, NOAA, Seattle, WA 98112, USA *Corresponding author: lewisakbarnett@gmail.com ABSTRACT: Despite evidence that mobile bottom fishing gear causes physical damage to habitat-forming organisms on the seafloor, likely indirectly affecting associated fishes, it is difficult to determine how conservation and management policies influence such effects because researchers do not typically systematically quantify the extent and intensity of gear-habitat interactions. Here, we estimated spatiotemporal trends in bottom trawling in areas containing biogenic habitat (sponges and corals) on the US west coast to evaluate the effect of spatial closures, catch shares, and vessel buybacks. We predicted highest probabilities of biogenic habitat occurrence in moderate to deep depths north of Cape Mendocino and off southern California, and highest gear-habitat interaction frequencies in moderate depths off Oregon and Washington. Temporal trends in total biogenic habitat contacts tracked changes in fishing effort, mostly declining between 2003 and 2014 (declines between start and end year ranged from 51-55% across taxa). However, the predicted frequency of contacts per unit effort increased by 17-56% across taxa from 2003-2009, coinciding with implementation of spatial closures, and our results indicate this was due to effort displacement and shifting spatial distribution of fishing. These relative interaction rates then declined by 10-34% after implementation of catch shares. Thus, although spatial closures may protect habitat within protected areas, without complementary policies, spatial closures may increase gear-habitat interactions in adjacent areas due to changes in fisher behavior and fishing effort displacement. KEY WORDS: Bottom trawling · Biogenic habitat · Catch shares · Spatial closures Full text in pdf format Supplementary material PreviousNextCite this article as: Barnett LAK, Hennessey SM, Essington TE, Shelton AO, Feist BE, Branch TA, McClure MM (2017) Getting to the bottom of fishery interactions with living habitats: spatiotemporal trends in disturbance of corals and sponges on the US west coast. Mar Ecol Prog Ser 574:29-47. https://doi.org/10.3354/meps12195 Export citation RSS - Facebook - Tweet - linkedIn Cited by Published in MEPS Vol. 574. Online publication date: July 04, 2017 Print ISSN: 0171-8630; Online ISSN: 1616-1599 Copyright © 2017 Inter-Research.

Implications for the structure of the Hat Creek fault and transfer of right-lateral shear from the Walker Lane north of Lassen Peak, northern California, from gravity and magnetic data

Interpretation of magnetic and new gravity data provides constraints on the geometry of the Hat Creek fault, the amount of right-lateral offset in the area between Mount Shasta and Lassen Peak (northern California, USA), and confirmation of the influence of preexisting structure on Quaternary faulting. Neogene volcanic rocks coincide with short-wavelength magnetic anomalies of both normal and reversed polarity, whereas a markedly smoother magnetic field occurs over the Klamath Mountains and Paleogene cover there. Although the magnetic field over the Neogene volcanic rocks is complex, the Hat Creek fault, which is one of the most prominent normal faults in the region and forms the eastern margin of the Hat Creek Valley, is marked by the eastern edge of a north-trending magnetic and gravity high 20–30 km long. Modeling of these anomalies indicates that the fault is a steeply dipping (∼75°–85°) structure. The spatial relationship of the fault as modeled by the potential-field data, the youngest strand of the fault, and relocated seismicity suggest that deformation continues to step westward across the valley, consistent with a component of right-lateral slip in an extensional environment. Filtered aeromagnetic data highlight a concealed magnetic body of Mesozoic or older age north of Hat Creek Valley. The body’s northwest margin strikes northeast and is linear over a distance of ∼40 km. Within the resolution of the aeromagnetic data (1–2 km), we discern no right-lateral offset of this body. Furthermore, Quaternary faults change strike or appear to end, as if to avoid this concealed magnetic body and to pass along its southeast edge, suggesting that preexisting crustal structure influenced younger faulting, as previously proposed based on gravity data.

The northward march of summer low cloudiness along the California coast

AbstractA new satellite‐derived low cloud retrieval reveals rich spatial texture and coherent space‐time propagation in summertime California coastal low cloudiness (CLC). Throughout the region, CLC is greatest during May–September but has considerable monthly variability within this summer season. On average, June is cloudiest along the coast of southern California and northern Baja, Mexico, while July is cloudiest along northern California's coast. Over the course of the summer, the core of peak CLC migrates northward along coastal California, reaching its northernmost extent in late July/early August, then recedes while weakening. The timing and movement of the CLC climatological structure is related to the summer evolution of lower tropospheric stability and both its component parts, sea surface temperature and potential temperature at 700 hPa. The roughly coincident seasonal timing of peak CLC with peak summertime temperatures translates into the strongest heat‐modulating capacity of CLC along California's north coast.

Challenges and opportunities in synthesizing historical geospatial data using statistical models

We classified land cover types from 1940s historical aerial imagery using Object Based Image Analysis (OBIA) and compared these maps with data on recent cover. Few studies have used these kinds of maps to model drivers of cover change, partly due to two statistical challenges: 1) appropriately accounting for spatial autocorrelation and 2) appropriately modeling percent cover which is bounded between 0 and 100 and not normally distributed. We studied the change in woody cover at four sites in California's North Coast using historical (1948) and recent (2009) high spatial resolution imagery. We classified the imagery using eCognition Developer and aggregated the resulting maps to the scale of a Digital Elevation Model (DEM) in order to understand topographic drivers of woody cover change. We used Generalized Additive Models (GAMs) with a quasi-binomial probability distribution to account for spatial autocorrelation and the boundedness of the percent woody cover variable. We explored the relative influences on current percent woody cover of topographic variables (grouped using principal component analysis) reflecting water retention capacity, exposure, and within-site context, as well as historical percent woody cover and geographical coordinates. We estimated these models for pixel sizes of 20, 30, 40, 50, 60, 70, 80, 90, and 100m, reflecting both tree neighborhood scales and stand scales. We found that historical woody cover had a consistent positive effect on current woody cover, and that the spatial autoregressive term in the model was significant even after controlling for historical cover. Specific topographic variables emerged as important for different sites at different scales, but no overall pattern emerged across sites or scales for any of the topographic variables we tested. This GAM framework for modeling historical data is flexible and could be used with more variables, more flexible relationships with predictor variables, and larger scales. Modeling drivers of woody cover change from historical ecology data sources can be a valuable way to plan restoration and enhance ecological insight into landscape change.

Where the Pavement Ends: An Assessment of the Near Absence of Haliotis rufescens in the Archaeological Record on Alta California's North Coast

Red abalone (Haliotis rufescens) is a common constituent in coastal middens south of San Francisco Bay and was such an important part of the diet there that red abalone middens or pavements are the most common site type in some areas at various periods in prehistory. The record north of San Francisco Bay stands in stark contrast—abalone are all but absent even in rich shell midden deposits. We explore four possible explanations for the lack of red abalone in the record, such as return rate discrepancies, competition with sea otters (Enhydra lutris), a lack of boat-based foraging, and the draw of terrestrial resources. We conclude that a combination of factors limited the appeal of red abalone for north coast foragers, including the inadequacy of boats as a platform for diving, competition with sea otters and, most importantly, enhanced terrestrial returns—including anadromous fish runs on coastal rivers—in northern California compared to southern California.

‘Oregon Snowflake’ Flowering Currant

Flowering currant (Ribes sanguineum Pursh.), also known as winter currant, is native to the West Coast of the United States, primarily west of the Coast Range from southern California north to British Columbia with populations also occurring in Idaho. The species is prized for its early spring flowers in pendulous racemes of 7 to 10 cm in colors including white, pink, and rose red. Improved cultivars have been selected primarily based on floral traits. These include White Icicle (= ‘Ubric’) with profuse white flowers on a shrub that reaches 2.5 m high and 1.8 m wide. ‘Pokey’s Pink’ and ‘King Edward VII’ are grown for their clear pink and red flowers, respectively. The growth habit of the species and most of its cultivars is larger than desired and the plants tend to become leggy and exhibit an overall poor form. ‘Oregon Snowflake’ was developed at Oregon State University (OSU) and released by the Oregon Agriculture Experiment Station for its improved plant habit, which is mounding and semidwarf as well as its unique leaf shape.

Low‐Cost Restoration Techniques for Rapidly Increasing Wood Cover in Coastal Coho Salmon Streams

AbstractLike many rivers and streams in forests of the Pacific Northwest, California north coast rivers and streams have been depleted of downed wood through timber harvest and direct wood removal. Due to the important role of wood in creating and maintaining salmonid habitat, wood augmentation has become a common element of stream restoration. Restoration efforts in North America often focus on building anchored, engineered wood structures at the site scale; however, these projects can fail to meet restoration goals at the watershed scale, do not closely mimic natural wood loading processes or dynamics, and can be expensive to implement. For critically imperiled populations of Coho Salmon Oncorhynchus kisutch in California, there is a strong impetus to achieve as much habitat restoration as possible in priority watersheds in the shortest time and with limited resources, so cost‐efficient techniques are necessary. In this multi‐site project, we investigated unanchored techniques for wood loading to evaluate cost and contribution to salmonid habitat in Mendocino County, California. Over a period of 6 years, 72.4 km of stream were treated with 1,973 pieces of strategically placed wood. We found that unanchored wood loading techniques were much less costly than commonly used anchored techniques, reliably improved habitat, and retained wood at high rates (mean = 92%) in small‐ to moderate‐sized streams, at least over the short term (<6 years). The average cost of design and construction for the unanchored projects was US$259 per log, equivalent to 22% of the cost associated with the anchored wood augmentation methods examined here. Our results suggest that this unanchored wood loading approach has the potential to increase the pace and scale at which wood augmentation projects are implemented in the Pacific Northwest and beyond.Received January 22, 2014; accepted June 25, 2014

Interview with Jeffrey L. Dangl.

Jeff Dangl was born in Grand Rapids, Michigan, USA. His family moved to Redding, in the beautiful north of California, when Jeff was aged 5. He grew up fishing in the lakes and streams of the great North State and hunting ducks and geese on the Pacific Flyway. This introduction to field biology spurred Jeff's interest, and he studied Biological Sciences and English, with a specialization in Modern Literature, at Stanford University as an undergraduate, earning dual Bachelor's degrees in 1981. Jeff had the good fortune to find a summer job in 1978, learning how to run and manage the fluorescence-activated cell sorter (FACS) in the lab of its creator, Prof.

The Changing Size Distribution of California's North Coast Wineries

AbstractIn this paper, we use three different goodness-of-fit tests for log-normality in conjunction with kernel nonparametric density estimation methods to examine both the size distribution of California North Coast wineries over time and by age. Our kernel density estimates indicate that the size distribution of wineries has changed from positively skewed to bimodal. These results are inconsistent with those in other industries, but are consistent with recent empirical research in the wine industry, which finds that smaller firms are comprising a larger component of market share. In terms of the distribution of firm size by age, our results indicate that as wineries age, the size distribution of firms becomes less skewed and more bimodal, which is also inconsistent with the research on other industries which finds that as firms age, the size distribution becomes more normal. Our results indicate that unlike other industries, where entry is very difficult, small firms can enter the wine industry and survive. (JEL Classifications: L11, L22, L25)

The Elusive West and the Contest for Empire, 1713-1763

Paul W. Mapp reframes the conventional US-centered history of the American West by studying the region’s claimants during the century preceding American supremacy. In the eighteenth century, three European nations (Great Britain, France, and Spain) and occasionally a fourth (Russia) strove to claim the territory that now forms the midwestern and western United States. According to Mapp, the failure of these powers to secure accurate geographical knowledge about the terrain (especially the Rocky Mountains) played a crucial role in their inability to establish hegemony over the territory. Of the three major powers, Britain remained the least interested in exploration overland into the interior of the continent, devoting its efforts instead to finding a northern water route from the Atlantic to the Pacific (the nonexistent Northwest Passage) and a second water route across the Pacific to the western coast of the present-day United States.France and Spain pursued the most aggressive land surveys of this territory prior to 1763. To explain how explorers from both countries failed to acquire sufficiently accurate geographic knowledge, Mapp points to the absence of a common language among the natives of the West. Indeed, no lingua franca existed among the many indigenous groups that served as informants for explorers from both countries. In California, where Spanish authorities expended most of their efforts, no common language or even language group existed. Even within today’s California there are more unrelated indigenous languages spoken than in any other state. Mapp also affirms that the French found similar linguistic diversity among the natives that they encountered as they journeyed south to the Gulf of Mexico and even New Mexico.In addition to these linguistic obstacles, Mapp notes the often violent push-back from resident natives. However, all Europeans faced armed opposition to their presence, including the British (and later the Americans). From the plains of Canada to Chile, subjugation of spread-out communities and especially nomadic groups remained slow, with conquests accumulating only over the course of decades and even centuries. In this respect, it would seem as though the perceived desirability of a territory would have influenced any decision to commit valuable military resources to it over an extended period of time. Most Latin American historians would have stressed the absence of valuable commodities to attract Spaniards to the West, especially when contrasted with the continuing wealth of silver pouring out of mines at this time in Mexico and Peru. Mapp, however, relegates this reason to a lesser place in the hierarchy of explanations.Additional factors highlighted by Mapp include the distance of the West from the established colonial centers of each group and the difficulties in reaching the interior of what is now the United States. Spaniards faced a lengthy and difficult overland trek to reach California, Arizona, New Mexico, and Texas. Coastal voyages were equally challenging: only a few reached as far north as an area near what is now San Francisco. Despite this struggle, Mapp faults Spanish explorers for failing to travel north of California, where they would have discovered the Columbia River and hence a path to the interior. French explorers in North America had a considerably less strenuous journey. They succeeded in traveling south from present-day Canada by following the flow of rivers into the vast Mississippi. Mapp also asserts that the French fundamentally misunderstood native mapping conventions. However, he suggests that by the time France ceded Louisiana to Spain in 1762, French explorers had learned enough to know that no easy path to the Pacific existed.Mapp does an excellent job of placing Spanish Bourbon political aims and actions in a multilateral and multinational context, moving the history of the American West toward a pluralistic vision encompassing the histories of French, Spanish, British, and, occasionally, Russian efforts that preceded the westward movement of people from the United States.

Making do with what we have: use your bootstraps

Key Points a jack knife is a pocket knife that is put to many tasks, because it's ready to hand. Often there could be a better tool for the job, such as a screwdriver, a scraper, or a can-opener, but these are not usually pocket items. In statistical terms, the expression implies making do with

The size distribution of California's north coast wineries: 1984‐2009

PurposeThe purpose of the paper is to examine the structure of California's north coast wine industry from 1984 to 2009, to determine if there are significant changes in the size distribution of wineries.Design/methodology/approachChi‐squared tests in conjunction with the Hoelter index are used to determine whether the changes in the market share for various size classes are significant.FindingsThe authors find a statistically significant trend in terms of smaller wineries becoming an increasing percentage of the total number of wineries and of market share.Originality/valueUnlike most other industries, small wineries are able to meet the changing market and technological conditions of the industry. These results augur well for the growing area of wine tourism which is highly dependent on boutique wineries. The results are also encouraging to new start up wineries considering entering the industry.

An integrated ecosystem trophic model for the North and Central Gulf of California: An alternative view for endemic species conservation

Understanding of the intricate interactions of endemic species with anthropogenic impacts of diverse economic interests on ecosystems is of paramount importance to the implementation of effective conservation programs. A trophic mass-balance model was used to analyze the structural properties of the North and Central Gulf of California (NC-GulfCal) ecosystem, the most important fishing area in Mexico and where conservation efforts for protecting the endangered endemic porpoise known as vaquita (Phocoena sinus) have been carried out for the last two decades. Results allowed to discuss the role of fisheries in the ecosystem and its implications for conservation of the endangered endemic porpoise. The trophic model was constructed with 166 functional groups and 3 regional fishing fleets. Abundance and catch from the early 1980s were used for balancing the model. Maturity indices of ascendency and production to respiration ratio indicate this ecosystem had a relatively high resilience and a high potential for development; this is in accordance with the highly variable environment found in the NC-GulfCal ecosystem. Mixed trophic impacts analysis confirms that pelagic and plankton groups have the most generalized impacts in this ecosystem. The model also shows that fisheries in the NC-GulfCal ecosystem, by the early 80s, were already operating in multiple habitats and landing a great variety of species. However, the highest exploitation pressure was focused on a few species. Although vaquita, since then, has also been under a high incidental mortality by gillnet fisheries, results suggest that predation should also be considered as a key factor on vaquita population dynamics and regulations focused exclusively on fisheries probably are not enough to achieve a successful vaquita recovery program.

Voltage Source Converter Based High-voltage DC System Modeling for Optimal Power Flow Studies

This article presents an enhanced model of a two-terminal voltage source converter based high-voltage DC system suitable for optimal power flow analysis in electric power systems. Both the back-to-back and the point-to-point voltage source converter and high-voltage DC schemes are addressed. Unlike to other proposals, the new model considers the operational constraints associated with the MVA ratings of the converters. The proposed model is implemented in a Newton-based optimal power flow approach and tested on the Baja California North 160-bus realistic power system. Simulation results show that a practically feasible optimal power flow solution can be obtained by considering the MVA converters' limits.

Felt Intensity versus Instrumental Ground Motion: A Difference between California and Eastern North America?

We examine the question of whether a single ground-motion intensity correlation equation (GMICE) is applicable to both eastern North America (ENA; intraplate) and California (interplate). We initially address this issue with the datasets from previous studies and separate them into central United States (CUS), California, and Canada datasets. We then add data from the 2008 M 5.2 Mt. Carmel, Illinois, and the 2005 M 4.7 Riviere du Loup earthquakes to the CUS and Canada datasets, respectively. For each dataset, the median of ground-motion values at each modified Mercalli intensity (MMI) level and their 95% confidence limits are calculated for peak ground velocity (PGV), peak ground acceleration (PGA), and spectral acceleration (SA) at 0.3, 1.0, and 2.0 s. The California median value is relatively higher than the CUS and Canada for PGV and SA at 1.0 and 2.0 s. Based on the median values and the associated uncertainty, we combine all datasets for PGA and 0.3-s SA in order to determine a GMICE. The CUS and Canada datasets are combined separately from California for PGV, 1.0-s SA, and 2.0-s SA. ENA earthquakes have a different spectral shape than those in California, particularly at intermediate periods (∼1.0 s) where ENA spectral amplitudes are reduced, which may explain the difference we see at longer periods. Finally, a log-linear-fit of MMI to the median values of ground motion is used to determine GMICE.

Landscape-Scale Vegetation Change Following Fire in Point Reyes, California, USA

Fire is an important factor in determining plant community composition and distribution. This study quantifies landscape-scale vegetation change following a large fire at Point Reyes National Seashore, California, USA. Vegetation in the Point Reyes region is characterized by a complex mosaic of grassland, shrub, and forest plant communities, and by high levels of plant diversity. Although large fires are relatively rare on the coast of California north of San Francisco Bay, they are important in determining the distributions of plant communities at the landscape scale. We mapped vegetation communities throughout the study area using aerial imagery and analyzed how vegetation shifted following fire. We found substantial areas had transitioned from coastal scrub to ceanothus scrub (Ceanothus thyrsiflorus Eschsch.) or Bishop pine (Pinus muricata D. Don) forest following fire. Transitions from shrub to tree vegetation following fire have rarely been documented in this region. Logistic regression analysis was used to examine the factors influencing the post-fire distribution of Bishop pine and ceanothus scrub. Proximity to pre-fire Bishop pine stands and pre-fire vegetation type were the most important predictors of post-fire Bishop pine regeneration. Pre-fire vegetation type, burn severity, and topography were the most important predictors of post-fire ceanothus scrub distribution. This study demonstrates the capacity of these ecosystems for substantial change over short time periods in response to fire, and identifies some of the factors driving this change.