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Texas Cities Lead Nation in Population Growth, Census Bureau Reports
Texas Cities Lead Nation in Population Growth, Census Bureau Reports
Source: U.S. Census Bureau
Eight of the 15 fastest-growing large U.S. cities and towns for the year ending July 1, 2012 were in Texas, according to population estimates released today by the U.S. Census Bureau. The Lone Star State also stood out in terms of the size of population growth, with five of the 10 cities and towns that added the most people over the year.
The fastest-growing municipalities are spread across Texas, from the High Plains of West Texas to the Houston suburbs. San Marcos, along the Interstate 35 corridor between Austin and San Antonio, had the highest rate of growth among all U.S. cities and towns with at least 50,000 people. Its population rose 4.9 percent between 2011 and 2012. Completing the top five nationwide were Midland and Cedar Park, both in Texas; South Jordan, Utah; and Clarksville, Tenn. No state other than Texas had more than one city on the list of the 15 fastest-growing large cities and towns. However, all but one were in the South or West. (See Table 1 for complete list.)
The Texas cities that added the most people included Houston, San Antonio, Austin, Dallas and Fort Worth. New York, the nation’s largest city, topped the list and was the only city among the top 15 outside the South or West. It added 67,058 people over the year. Three cities were in California: Los Angeles, San Diego and San Jose. (See Table 2 for complete list.)
New York continued to be the nation’s most populous city by a wide margin, with 8.3 million residents in 2012, followed by Los Angeles and Chicago. The composition of the list of the 15 most populous cities has remained unchanged since last year; however, the list’s order has changed slightly. Between 2011 and 2012, Austin moved up from 13th to 11th in total population, supplanting Jacksonville, Fla., while Indianapolis moved down from 12th to 13th. Texas and California each had four cities on the list in both years. (See Table 3 for complete list.)
The estimates released today cover all local governmental units, including incorporated places (like cities and towns), minor civil divisions (such as townships) and consolidated cities (government units for which the functions of an incorporated place and its parent county have merged).
The Racial/Ethnic Distribution of Heat Risk-Related Land Cover in Relation to Residential Segregation
Source: Environmental Health Perspectives
Objective: To examine the distribution of heat risk-related land cover (HRRLC) characteristics across racial/ethnic groups and degrees of residential segregation.
Methods: Block group-level tree canopy and impervious surface estimates were derived from the 2001 National Land Cover Dataset for densely populated urban areas of the United States and Puerto Rico, and linked to demographic characteristics from the 2000 Census. Racial/ethnic groups in a given block group were considered to live in HRRLC if at least half their population experienced the absence of tree canopy and at least half of the ground covered by impervious surface (roofs, driveways, sidewalks, roads). Residential segregation was characterized for metropolitan areas in the United States and Puerto Rico using the multigroup dissimilarity index.
Results: After adjusting for ecoregion and precipitation, and holding segregation level constant, non-Hispanic blacks were 52% more likely (95% confidence interval (CI): 37% to 69%), non-Hispanic Asians 32% more likely (95% CI: 18% to 47%), and Hispanics 21% more likely (95% CI: 8% to 35%) to live in HRRLC conditions compared to non-Hispanic whites. Within each racial/ethnic group, HRRLC conditions increased with increasing degrees of metropolitan area-level segregation. Further adjustment for home ownership and poverty did not substantially alter these results, but adjustment for population density and metropolitan area population attenuated the segregation effects, suggesting a mediating or confounding role.
Conclusions: Land cover was associated with segregation within each racial/ethnic group, which may be partially explained by the concentration of racial/ethnic minorities into densely populated neighborhoods within larger, more segregated cities. In anticipation of greater frequency and duration of extreme heat events, climate change adaptation strategies, such as planting trees in urban areas, should explicitly incorporate an environmental justice framework that addresses racial/ethnic disparities in HRRLC.
See: Racial minorities live on the front lines of heat risk, study finds (EurekAlert!)
Market-oriented education reforms’ rhetoric trumps reality
Market-oriented education reforms’ rhetoric trumps reality (PDF)
Source: Economic Policy Institute
Top-down pressure from federal education policies such as Race to the Top and No Child Left Behind, bolstered by organized advocacy efforts, is making a popular set of market-oriented education “reforms” look more like the new status quo than real reform. Reformers assert that test-based teacher evaluation, increased access to charter schools, and the closure of “failing” and under-enrolled schools will boost at-risk students’ achievement and narrow longstanding race- and income-based achievement gaps. This new report from the Broader, Bolder Approach to Education examines these assertions by comparing the impacts of these reforms in three large urban school districts – Washington, D.C., New York City, and Chicago – with student and school outcomes over the same period in other large, high-poverty urban districts. The report finds that the reforms deliver few benefits, often harm the students they purport to help, and divert attention from a set of other, less visible policies with more promise to weaken the link between poverty and low educational attainment.
Speed
Speed (PDF)
Source: University of Toronto
We investigate the determinants of driving speed in large us cities. We first estimate city level supply functions for travel in an econometric framework where both the supply and demand for travel are explicit. These estimations allow us to calculate a city level index of driving speed and to rank cities by driving speed. Our investigation of the determinants of speed provide the foundations for a welfare analysis. This analysis suggests that large gains in speed may be possible if slow cities can emulate fast cities and that the deadweight losses from congestion are sizeable.
See: A Need for Speed: Why Building More Roads Won’t Conquer Gridlock (Knowledge@Wharton)
Using Public Surveillance Systems for Crime Control and Prevention: A Practical Guide for Law Enforcement and Their Municipal Partners
Source: Urban Institute
Municipalities across the country are in a constant search for effective public safety interventions that will curb crime and improve the livability and economic well-being of their communities. This is particularly true among law enforcement agencies that embrace a community policing philosophy, which has become a key component of policing efforts in most mid- and large-sized law enforcement agencies across the United States. While many believe that the adoption of community policing has led to more efficient and effective policing strategies, law enforcement agencies continue to grapple with limited resources and are therefore interested in employing new, cost-effective tools that can enhance their community policing efforts. Among the latest wave of public safety tools is the use of public surveillance systems, often referred to as Closed-Circuit Television (CCTV). While public surveillance systems are widely employed in the business sector to improve security, until recently the use of cameras to monitor public spaces has been much less common in the United States, in part due to concerns about privacy and civil liberties. Community policing, which embodies a combination of proactive crime prevention and community engagement with more traditional policing functions, may benefit from this technology because public surveillance can enhance problem solving strategies, aid in arrests and investigations, and ultimately increase offenders’ perceptions that they will be both caught and prosecuted. Public surveillance systems might also yield a secondary impact, serving to increase legitimate users’ perceptions of safety and thus their presence in public areas, which in turn may increase guardianship, improve police-community partnerships, and reduce crime.
The potential contributions to policing and public safety of public surveillance systems perhaps explain why their use has expanded in recent years. Unfortunately, these investments of scarce public safety resources are being made in the absence of research documenting the decisions behind camera investment and use and the lessons learned by cities that have employed this technology.
This guidebook aims to fill that gap, detailing the results of an in-depth qualitative data collection effort to examine and synthesize the experiences of three large urban cities that have invested in public surveillance systems in recent years. It serves as a companion document to an evaluation of the impact of public surveillance cameras in three cities that found that cameras can have a significant and cost-effective impact on crime.10 While cameras hold promise as an effective crime prevention tool, however, it is important to note that their impact is not a given, and varies considerably based on where cameras are located and the degree to which they are monitored and integrated into other law enforcement activities. This report is therefore designed to guide city administrators, law enforcement agencies, and their municipal partners in making decisions regarding their public surveillance systems in a manner that will yield the greatest intended impact. The guidebook answers many of the important questions that arise when implementing or expanding a public surveillance system. It details the various aspects of a system that are integral in realizing a cost-beneficial impact on crime, including budgetary considerations, camera types and locations, how best to monitor cameras, and the role that video footage plays in investigations and prosecutions. This publication also highlights the most prominent lessons learned in an effort to guide both city administrators and jurisdictions that are currently investing in cameras for public safety purposes, as well as inform those that are contemplating doing so.
City-Level Decoupling: urban resource flows and the governance of infrastructure transitions (2013)
City-Level Decoupling: urban resource flows and the governance of infrastructure transitions (2013)
Source: United Nations Environmental Programme
Building upon previous work of the International Resource Panel on Decoupling Natural Resource Use and Environmental Impacts from Economic Growth, this report examines the potential for decoupling at the city level. While the majority of the world’s population now live in cities and cities are where most resource consumption takes place, both the pressures and potentials to find ways to reconcile economic growth, wellbeing and the sustainable use of natural resources will therefore be greatest in cities.
Analysing the role of cities as spatial nodes where the major resource flows connect as goods, services and wastes, the report ‘s focus is how infrastructure directs material flows and therefore resource use, productivity and efficiency in an urban context. It makes the case for examining cities from a material flow perspective, while also placing the city within the broader system of flows that make it possible for it to function.
The report also highlights the way that the design, construction and operation of energy, waste, water, sanitation and transport infrastructures create a socio-technical environment that shapes the “way of life” of citizens and how they procure, use and dispose of the resources they require. Its approach is innovative in that it frames infrastructure networks as socio-technical systems, examining pressures for change within cities that go beyond technical considerations. The importance of intermediaries as the dominant agents for change is emphasized, as well as the fact that social processes and dynamics need to be understood and integrated into any assessment of urban infrastructure interventions and the reconfiguration of resource flows.
A set of 30 case studies provide examples of innovative approaches to sustainable infrastructure change across a broad range of urban contexts that could inspire leaders of other cities to embrace similar creative solutions. Of course, innovations in and of themselves do not suffice if they are not integrated into larger strategic visions for the city, and as each city is unique, interventions need to be tailored to the set of challenges and opportunities present in each case.
Job Sprawl Stalls: The Great Recession and Metropolitan Employment Location
Job Sprawl Stalls: The Great Recession and Metropolitan Employment Location
Source: Brookings Institution
As policymakers and regional leaders work to grow jobs and connect residents to economic opportunity following the Great Recession, where jobs locate matters. The location of employment within a metro area intersects with a range of policy issues—from transportation to workforce development to regional innovation—that affect a region’s long-term health, prosperity, and social inclusion.
An analysis of the location of private-sector employment within 35 miles of a downtown in the nation’s 100 largest metropolitan areas from 2007 to 2010, and across the 2000s, finds:
Steep employment losses following the Great Recession stalled the steady decentralization of jobs that characterized the early to mid-2000s. After dropping 2 percentage points from 2000 to 2007, the share of metropolitan jobs within 3 miles of downtown stabilized from 2007 to 2010. However, by 2010 nearly twice the share of jobs was located at least 10 miles away from downtown (43 percent) as within 3 miles of downtown (23 percent).
Job losses in industries hit hardest by the downturn, including construction and manufacturing, helped check employment decentralization in the late 2000s. Together, construction, manufacturing, and retail—each among the most decentralized of major industries—accounted for almost 60 percent of all job losses between 2007 and 2010, with half of those losses occurring at least 10 miles from downtown.
In all but nine of the 100 largest metro areas, the share of jobs located within three miles of downtown declined during the 2000s. Only Washington, D.C. experienced an increase in both the number and share of jobs located in the urban core during the 2000s. At the same time, the share of jobs at least 10 miles from downtown rose in 85 regions between 2000 and 2010.
A metro area’s total employment, and policy and planning decisions around land use, economic development, and zoning, help shape the location of its jobs. Employment is more decentralized in metro areas with at least 500,000 jobs. But even large metro areas with high degrees of job decentralization like Chicago and Detroit concentrate many of their jobs in dense locations outside the urban core.
Minneapolis-St. Paul Area Residents Most Likely to Feel Safe; Memphis area residents least likely to feel safe
Source: Gallup
Eighty percent of those living in the Minneapolis-St. Paul area say they feel safe walking alone at night in the area where they live, the highest percentage among the 50 largest U.S. metropolitan areas. Minneapolis is followed closely by Denver, Raleigh, Boston, Salt Lake City, and Austin.
Next Stop, Innovation: What’s Ahead for Urban Mobility?
Next Stop, Innovation: What’s Ahead for Urban Mobility?
Source: Knowledge@Wharton (University of Pennsylvania)
Transportation in the 21st century is entering a robust phase that mirrors the early years of the automobile, when gasoline, steam and electric technology vied for market share. Although electric cars led for a while, the internal-combustion engine reached dominance by 1920, with profound effects on American city-based public transportation — which atrophied as car ownership grew.
Today, urban transit is making a comeback, as is the electric car. Congested highways still face emission concerns, but consumers now often have the choice of light and heavy rail. Car sharing, which began as a European phenomenon, has prospered in U.S. urban centers, along with bicycle sharing, vanpooling and other options.
Government plays a major role in shaping efficient urban transportation systems. So far, regulations have proven an effective driver in the early development of new technology. But for ultimate success, environmentally friendly options also must satisfy consumers’ needs and meet economic goals. This special report, produced in coordination with Wharton’s Initiative for Global Environmental Leadership (IGEL), explores how cities are expanding their options for cleaner transportation, and how new technologies, innovations and incentives are revitalizing the sector.
Underground Engineering for Sustainable Urban Development
Underground Engineering for Sustainable Urban Development
Source: National Research Council
For thousands of years, the underground has provided humans refuge, useful resources, physical support for surface structures, and a place for spiritual or artistic expression. More recently, many urban services have been placed underground. Over this time, humans have rarely considered how underground space can contribute to or be engineered to maximize its contribution to the sustainability of society. As human activities begin to change the planet and population struggle to maintain satisfactory standards of living, placing new infrastructure and related facilities underground may be the most successful way to encourage or support the redirection of urban development into sustainable patterns. Well maintained, resilient, and adequately performing underground infrastructure, therefore, becomes an essential part of sustainability, but much remains to be learned about improving the sustainability of underground infrastructure itself.
At the request of the National Science Foundation (NSF), the National Research Council (NRC) conducted a study to consider sustainable underground development in the urban environment, to identify research needed to maximize opportunities for using underground space, and to enhance understanding among the public and technical communities of the role of underground engineering in urban sustainability.
Underground Engineering for Sustainable Urban Development explains the findings of researchers and practitioners with expertise in geotechnical engineering, underground design and construction, trenchless technologies, risk assessment, visualization techniques for geotechnical applications, sustainable infrastructure development, life cycle assessment, infrastructure policy and planning, and fire prevention, safety and ventilation in the underground. This report is intended to inform a future research track and will be of interest to a broad audience including those in the private and public sectors engaged in urban and facility planning and design, underground construction, and safety and security.
Worldwide cost of living index 2013
Worldwide cost of living index 2013
Source: Economist
After currency swings pushed Zurich to the top of the ranking last year, Tokyo has resumed its place as the world’s most expensive city. This is a familiar position for the Japanese capital which has been the world’s most expensive city for all but a handful of the last 20 years. In fact, since 1992 Tokyo has been the ranking city in every year bar six. Only Zurich, Paris and Oslo were dubbed the world’s most expensive city during this time.
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Context-Aided Sensor Fusion for Enhanced Urban Navigation
Context-Aided Sensor Fusion for Enhanced Urban Navigation
Source: Sensors
The deployment of Intelligent Vehicles in urban environments requires reliable estimation of positioning for urban navigation. The inherent complexity of this kind of environments fosters the development of novel systems which should provide reliable and precise solutions to the vehicle. This article details an advanced GNSS/IMU fusion system based on a context-aided Unscented Kalman filter for navigation in urban conditions. The constrained non-linear filter is here conditioned by a contextual knowledge module which reasons about sensor quality and driving context in order to adapt it to the situation, while at the same time it carries out a continuous estimation and correction of INS drift errors. An exhaustive analysis has been carried out with available data in order to characterize the behavior of available sensors and take it into account in the developed solution. The performance is then analyzed with an extensive dataset containing representative situations. The proposed solution suits the use of fusion algorithms for deploying Intelligent Transport Systems in urban environments.
See: Precision of GPS in Cities Improved by 90 Percent (Science Daily)
Explaining Charter School Effectiveness
Explaining Charter School Effectiveness (PDF)
Source: American Economic Journal: Applied Economics (forthcoming)
Estimates using admissions lotteries suggest that urban charter schools boost student achievement, while charter schools in other settings do not. We explore student-level and school-level explanations for this difference using a large sample of lotteried applicants to charter schools in Massachusetts. In an econometric framework that isolates sources of charter effect heterogeneity, we show that urban charter schools boost achievement well beyond that of urban public school students, while non-urban charters reduce achievement from a higher baseline. Student demographics explain some of these gains since urban charters are most effective for non-whites and low-baseline achievers. At the same time, non-urban charter schools are uniformly ineffective. Our estimates also reveal important school-level heterogeneity within the urban charter sample. A non-lottery analysis suggests that urban charters with binding, well-documented admissions lotteries generate larger score gains than under-subscribed urban charter schools with poor lottery records. Using a detailed survey of school practices and characteristics, we link charter impacts to inputs such as instructional time, classroom techniques and school philosophy. The relative effectiveness of urban lottery- sample charters is accounted for by these schools’ embrace of the No Excuses approach to urban education.
What City Leaders Need to Know as Countries Rapidly Urbanize
What City Leaders Need to Know as Countries Rapidly Urbanize
Source: World Bank
Today’s developed countries urbanized mostly gradually, their cities expanding over a period of 100 years or more as jobs shifted from farms to factories. The pace allowed for trial and error in growth patterns and policies. Developing countries today don’t have that luxury. They’re facing rapid migration that will tilt some populations from less than 20 percent urban today to more than 60 percent in just 30 years.
City leaders must figure out now how they will provide the affordable homes, transportation, jobs, and basic infrastructure and services necessary to support already ballooning urban populations, do so with the least impact on the environment and prepare for increasing vulnerabilities stemming from climate change.
Getting this rapidly paced urbanization right is the key to resilient and sustainable growth. The challenge goes well beyond planning – governments must find innovative ways to finance infrastructure.
A new World Bank report, Planning, Connecting and Financing-Now: What City Leaders Need to Know, provides a framework for urban growth planning and finance, backed by case studies, to help leaders identify the impediments to urbanization and find the right combinations of policy options that would work politically, technically, and fiscally for their cities and countries. It helps them think through questions such as, What must be done to create jobs and expand basic services? What must be done to improve living conditions in slums and hazard-prone areas? What must be done to manage the city’s physical form?
A New ULI Publication, Shifting Suburbs, Examines Creative Use And Adaptation Of Infrastructure To Support Compa ct Development In America’s Suburbs
Source: Urban Land Institute
Successful strategies for creatively using and adapting infrastructure to support more dense development in America’s suburbs are highlighted in Shifting Suburbs: Reinventing Infrastructure for Compact Development, a new report from the Urban Land Institute (ULI).
The report focuses on the growing trend for suburbs to be redesigned and redeveloped to be more people-oriented than car-dependent, offering more options for walking, cycling or using public transit to get from one place to another. With the U.S. population anticipated to grow by 95 million people over the next 30 years, and with the vast majority of this growth expected to occur in the suburbs of metropolitan areas, the challenge of providing the appropriate infrastructure to encourage compact growth has never been more important, notes Shifting Suburbs. Specifically, suburban arterials and first ring suburbs would benefit from the development of new approaches to solving infrastructure and land use challenges, it says.
The steady movement toward more compact suburban growth is being driven in part by Generation Y, a key demographic group (numbering 80 million) entering the housing and jobs market. These young professionals tend to favor the convenience and choices provided by urban-style environments, but often live outside of city centers for employment or financial reasons. Fitting their lifestyle preferences into a suburban setting has, in many markets, triggered a movement to rethink traditional infrastructure design, the report says.
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Shifting Suburbs examines in extensive detail eight suburban infrastructure projects: Bridge Street Corridor in Dublin, Ohio; Aurora Corridor in Shoreline, Wash.; Belmar in Lakewood, Colo.; State Route 7 in Broward and Miami-Dade Counties, Fla.; White Flint/Rockville Pike in Montgomery County, Md.; Richardson, Texas; CityCentre in Houston, Tex.; and West End in St. Louis Park, Minn. The report evaluates the significant challenges faced by these places in trying to establish themselves as more compact suburban locations, including overcoming community resistance, obtaining the necessary funding, negotiating cross-jurisdictional planning issues, and establishing the required skill sets among the public and private organizations delivering redevelopment projects.
As Traffic Jams Worsen, Commuters Allowing Extra Time for Urgent Trips
As Traffic Jams Worsen, Commuters Allowing Extra Time for Urgent Trips
Source: Texas Transportation Institute (Texas A&M University)
As traffic congestion continues to worsen, the time required for a given trip becomes more unpredictable, and researchers now have a way to measure that degree of unreliability, introduced for the first time as part of the annual Urban Mobility Report (UMR), published by the Texas A&M Transportation Institute (TTI).
The Planning Time Index (PTI), a measure of travel reliability, illustrates the amount of extra time needed to arrive on time for higher priority events, such as an airline departure, just-in-time shipments, medical appointments or especially important social commitments. If the PTI for a particular trip is 3.00, a traveler would allow 60 minutes for a trip that typically takes 20 minutes when few cars are on the road. Allowing for a PTI of 3.00 would ensure on-time arrival 19 out of 20 times.
PTIs on freeways vary widely across the nation, from 1.31 (about nine extra minutes for a trip that takes 30 minutes in light traffic) in Pensacola, Florida, to 5.72 (almost three hours for that same half-hour trip) in Washington, D.C., according to the study by TTI, a member of The Texas A&M University System.
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Rankings of the nation’s most congested cities vary slightly from year to year, and many of this year’s top 10 are repeat performers. Washington, D.C. tops the list, followed by Los Angeles, San Francisco-Oakland, New York-Newark and Boston. The second five include Houston, Atlanta, Chicago, Philadelphia and Seattle. The report provides a detailed illustration of traffic problems in a total of 498 U.S. urban areas.In addition to PTI, the 2012 UMR also debuts an estimate of the additional carbon dioxide (CO2) emissions attributed to traffic congestion: 56 billion pounds – about 380 pounds per auto commuter.
Patenting Prosperity: Invention and Economic Performance in the United States and its Metropolitan Areas
Source: Brookings Institution
“Patenting Prosperity: Invention and Economic Performance in the United States and its Metropolitan Areas” is the first analysis of its kind to present patenting trends on a regional level from 1980 to 2012. The report ranks all of the nation’s roughly 360 metropolitan areas on patenting levels and growth, while noting the firms and organizations responsible. It also analyzes how patenting has affected productivity levels in each region, comparing patents—which embody novel inventions—to other sources of economic dynamism, such as educational attainment.
This report examines the importance of patents as a measure of invention to economic growth and explores why some areas are more inventive than others. Why should we expect there to be a relationship between patenting and urban economic development? As economist Paul Romer has written, the defining nature of ideas, in contrast to other economic goods, is that they are non-rival: their use by any one individual does not preclude others from using them. Although useful ideas can be freely transmitted and copied, the patent system guarantees, in principle, temporary protection from would-be competitors in the marketplace (i.e. excludability). Thus, one would expect regions to realize at least some of the value of invention, as has been shown for individual inventors and companies that patent. Yet there is no guarantee that patents generated in a specific location will generate wealth in that same location—a set of conditions (the presence of a skilled and diverse labor force, an “ecosystem” of businesses providing complementary goods and services, financing and marketing capabilities among them) have to be met for invention to be commercialized. Research has established that patents are correlated with economic growth across and within the same country over time. Yet, metropolitan areas play a uniquely important role in patenting, and the study of metropolitan areas within a single large country—the United States—allows one to isolate the role of patents from other potentially confounding factors like population size, industry concentration, and workforce characteristics.
Municipal Equality Index
Municipal Equality Index
Source: Human Rights Campaign
The Municipal Equality Index (MEI), the first ever rating system of LGBT inclusion in municipal law, finds that while many U.S. cities lag behind in protections for LGBT people, some of the most LGBT-friendly policies in the country have been innovated and implemented at the municipal level, including in states with laws that are unfriendly to the LGBT community.
The MEI rates cities based on 47 criteria falling under six broad categories: non-discrimination laws; relationship recognition; the municipality’s employment practices; inclusiveness of city services; law enforcement; and municipal leadership. Key findings from the MEI create a snapshot of LGBT equality in 137 municipalities of varying sizes drawn from every state in the nation – these include the 50 state capitals, the 50 most populous cities in the country, and the 25 large, 25 mid-size, and 25 small municipalities with the highest proportion of same-sex couples. Seattle and other 100-point cities serve as shining examples of LGBT inclusivity, with excellent policies ranging from non-discrimination laws, equal employee benefits, and cutting-edge city services.
Bird song and anthropogenic noise: vocal constraints may explain why birds sing higher-frequency songs in cities
Source: Proceedings of the Royal Society B
When animals live in cities, they have to adjust their behaviour and life histories to novel environments. Noise pollution puts a severe constraint on vocal communication by interfering with the detection of acoustic signals. Recent studies show that city birds sing higher-frequency songs than their conspecifics in non-urban habitats. This has been interpreted as an adaptation to counteract masking by traffic noise. However, this notion is debated, for the observed frequency shifts seem to be less efficient at mitigating noise than singing louder, and it has been suggested that city birds might use particularly high-frequency song elements because they can be produced at higher amplitudes. Here, we present the first phonetogram for a songbird, which shows that frequency and amplitude are strongly positively correlated in the common blackbird (Turdus merula), a successful urban colonizer. Moreover, city blackbirds preferentially sang higher-frequency elements that can be produced at higher intensities and, at the same time, happen to be less masked in low-frequency traffic noise.
See: Clamorous City Blackbirds: Birds Can Sing Louder at Higher Frequencies to Make Themselves Heard Over Traffic Noise (Science Daily)
US Forest Service Forecasts Trends and Challenges for Next 50 Years
US Forest Service Forecasts Trends and Challenges for Next 50 Years
Source: U.S. Forest Service
A comprehensive U.S. Forest Service report released today examines the ways expanding populations, increased urbanization, and changing land-use patterns could profoundly impact natural resources, including water supplies, nationwide during the next 50 years.
Significantly, the study shows the potential for significant loss of privately-owned forests to development and fragmentation, which could substantially reduce benefits from forests that the public now enjoys including clean water, wildlife habitat, forest products and others.
