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Buffelgrass [Pennisetum ciliare (L.) Link] is an invasive C4 perennial bunchgrass that is a threat to biodiversity in aridlands in the Americas and Australia. Topography influences P. ciliare occurrence at large spatial scales, but further investigation into the relationship between local-scale topography and P. ciliare growth and reproduction would be beneficial. Further, density-dependent effects on P. ciliare growth and reproduction have been demonstrated in greenhouse experiments, but the extent to which density dependence influences P. ciliare in natural populations warrants further investigation. Here we present a study on the relationships between local-scale topography (aspect and slope gradient) and vegetation characteristics (shrub cover, P. ciliare cover, and P. ciliare density) and their interactions on individual P. ciliare plant size and reproduction. We measured slope gradient, aspect, shrub cover, P. ciliare cover, P. ciliare density, and the total number of live culms and reproductive culms of 10 P. ciliare plants in 33 4 by 4 m plots located in 11 transects at the Desert Laboratory at Tumamoc Hill, Tucson, AZ, USA. We modeled the relationships at the local scale of (1) P. ciliare cover and density with aspect and slope gradient and (2) P. ciliare size and reproduction with abiotic (slope gradient and aspect) and biotic (P. ciliare cover and density and native shrub and cacti cover) characteristics. Aspect and slope gradient were poor predictors of P. ciliare cover and density in already invaded sites at the scale of our plots. However, aspect had a significant relationship with P. ciliare plant size and reproduction. Pennisetum ciliare plants on south-facing aspects were larger and produced more reproductive culms than plants on other aspects. Further, we found no relationship between P. ciliare density and P. ciliare plant size and reproduction. Shrub cover was positively correlated with P. ciliare reproduction. South-facing aspects are likely most vulnerable to fast spread and infilling by new P. ciliare introductions.

Aim: Addressing global environmental challenges requires access to biodiversity data across wide spatial, temporal and taxonomic scales. Availability of such data has increased exponentially recently with the proliferation of biodiversity databases. However, heterogeneous coverage, protocols, and standards have hampered integration among these databases. To stimulate the next stage of data integration, here we present a synthesis of major databases, and investigate (a) how the coverage of databases varies across taxonomy, space, and record type; (b) what degree of integration is present among databases; (c) how integration of databases can increase biodiversity knowledge; and (d) the barriers to database integration. Location: Global. Time period: Contemporary. Major taxa studied: Plants and vertebrates. Methods: We reviewed 12 established biodiversity databases that mainly focus on geographic distributions and functional traits at global scale. We synthesized information from these databases to assess the status of their integration and major knowledge gaps and barriers to full integration. We estimated how improved integration can increase the data coverage for terrestrial plants and vertebrates. Results: Every database reviewed had a unique focus of data coverage. Exchanges of biodiversity information were common among databases, although not always clearly documented. Functional trait databases were more isolated than those pertaining to species distributions. Variation and potential incompatibility of taxonomic systems used by different databases posed a major barrier to data integration. We found that integration of distribution databases could lead to increased taxonomic coverage that corresponds to 23 years’ advancement in data accumulation, and improvement in taxonomic coverage could be as high as 22.4% for trait databases. Main conclusions: Rapid increases in biodiversity knowledge can be achieved through the integration of databases, providing the data necessary to address critical environmental challenges. Full integration across databases will require tackling the major impediments to data integration: taxonomic incompatibility, lags in data exchange, barriers to effective data synchronization, and isolation of individual initiatives.

Invasive plants can have significant negative effects on human and ecological communities, including reduced productivity and biodiversity and increased fire risk. Effective mitigation of invasive species likely requires action by heterogeneous actors who span jurisdictions, sectors, and levels of governance. While there has been significant research to develop targeted mitigation techniques that slow or halt the spread of specific invasive plants, there has been relatively little complementary work to develop knowledge about the implementation of these management techniques through effective governance systems. To address this gap, we interviewed and conducted archival research on land managers involved in the mitigation of buffelgrass (Pennisetum ciliare, syn: Cenchrus ciliarus) invasion in southern Arizona to investigate how existing and emerging governance arrangements encourage or undermine individual and collective action to manage invasive plants. Our results show that a key challenge of managing invasive species is identifying the mechanisms that will allow heterogeneous actors to overcome internal barriers to coordination with others and enable collective action. These internal barriers are multifaceted, involving laws and policies, cultural traditions and mandates, the availability of monetary and human resources, and information on causes and consequences of species invasion and effective approaches to mitigation. Approaches to solving these problems must include improved knowledge of internal institutional structures and the opportunities and barriers they present to collective action, the preferences of heterogeneous actors when presented with information about future ecosystem conditions absent coordination, the factors that prevent individuals within different organizations from following through on commitments to participate in collective action institutions, and how each of these conditions affects the availability and persistence of resources for mitigation. Together, improved knowledge of the relationships between these factors may provide new approaches to proactive management of emerging resource management challenges, from invasive species to emerging diseases.

We show the strong substitutes product-mix auction bidding language provides an intuitive and geometric interpretation of strong substitutes as Minkowski differences between sets that are easy to identify. We prove that competitive equilibrium prices for agents with strong substitutes preferences can be computed by minimizing the difference between two linear programs for the positive and the negative bids with suitably relaxed resource constraints. This also leads to a new algorithm for computing competitive equilibrium prices which is competitive with standard steepest descent algorithms in extensive experiments.

INTRODUCTION AND OBJECTIVE:The novel thulium fiber laser (TFL) has advantages compared to the Holmium laser (HL) including smaller fiber size (150 μm) and higher frequency settings (up to 2000 Hz)....

In many policy arenas, decision makers have supplemented or even replaced traditional forms of bureaucratic decision making with more participatory approaches to governance. While theory suggests that participatory governance can have an instrumental effect on policy outcomes, there have been few efforts to systematically test these theories across multiple jurisdictions. This study asks whether and how participatory governance in electric sector regulation affects utilities’ energy savings. Using a mixed-methods research design, this study develops hypotheses drawn from participatory governance theory, analyzes regulatory documents to operationalize a set of participatory governance variables, and uses a multilevel fixed effects model to test whether these participatory governance variables have an effect on electricity consumption by customers of 250 utilities across 42 states between 2000 and 2015. Model results show that deliberation among stakeholders has a significant decrease in electricity use by consumers, but that this effect must be realized over time as stakeholders gain experience with the deliberative process. To explore why deliberation produces this effect, the study presents qualitative evidence from Connecticut and Maryland, two states that have used participatory governance to regulate utilities’ energy efficiency plans. Results suggest that information exchange among participants has a direct effect on utilities’ energy efficiency plans. Participatory governance also contributes to a network of engaged stakeholders who can help hold utilities accountable for achieving their savings goals.

The international environmental community and many donor countries have encouraged developing countries to adopt renewable energy (RE) policies that will encourage low-carbon energy development. While the drivers of RE policy adoption have been well-studied in the U.S. and Europe, we know little about the factors that drive RE policy adoption in developing countries. Both theory and anecdotal evidence suggest that policies often spread when one country emulates another’s policy, but scholars of policy diffusion have tended to focus on emulation of political and ideological peers, overlooking other factors that may be particularly critical for driving RE policy adoption, including emulation of peers with similar electric sector conditions and emulation that is driven by coercive donor-recipient aid relationships. We use a directed dyadic analysis to assess the factors that prompt a country to emulate another’s policies and to determine whether emulation patterns differ across developed and developing countries. We find that both sets of countries tend to emulate the policies of their political peers, and that developing countries tend to emulate the policies of donors. The effect of electric sector similarities varies by policy type. Countries emulate feed-in tariffs of countries with similar electric sector conditions, but they emulate quota policies of countries with dissimilar levels of reliance on renewable energy. Results suggest that different policies may diffuse via different emulation patterns.

Electricity access in sub-Saharan Africa is the lowest amongst all regions of the world. In response, since the 1990s, the World Bank and other donors have pushed African countries to reform their electricity sectors. While a “standard model” of liberalization reforms has been endorsed, the timing, pace and extent of reform adoption and implementation undertaken by countries varies significantly. This paper asks: why do some countries adopt electricity sector reforms more quickly and more fully than others? The paper uses a comparative historical analysis of Ghana, Tanzania and Uganda to answer this question. Each country’s experience with reform varies. Our study finds that the timing of reform was largely contingent on economic factors, primarily the need for financing to improve sector efficiency. The pace of reform was shaped largely by international political considerations, namely differences in the countries’ reliance on aid from key donors, especially the World Bank. And the extent of reform was determined primarily by internal national political factors. Specifically, where elite decision-makers faced a historically-grounded national ideology that created citizen expectations that the state provide electricity, a competitive democratic regime, and stronger civil society, electricity sector reforms were less extensive. The paper makes an important contribution to understanding the politics of institutional change. We show how African governments exercise autonomy and resistance, both internationally with donors, and domestically, in the rewriting of institutional rules; that reforms are contingent on political calculations by national political elites about domestic conditions and needs; and that global norms are not sufficient to cause policy change. Overcoming energy poverty in Africa is expected to remain a challenge for the foreseeable future. As new development partners replace or complement the World Bank’s role in African energy sectors, attention to how domestic institutions and politics engage with global norms is critical.

The National Environmental Policy Act (NEPA) of 1969 requires federal agencies to analyze the environmental impacts of proposed actions that could impact the human environment, as well as c...

We show that, with indivisible goods, the existence of competitive equilibrium fundamentally depends on agents' substitution effects, not their income effects. Our Equilibrium Existence Duality allows us to transport results on the existence of competitive equilibrium from settings with transferable utility to settings with income effects. One consequence is that net substitutability---which is a strictly weaker condition than gross substitutability---is sufficient for the existence of competitive equilibrium. We also extend the ``demand types'' classification of valuations to settings with income effects and give necessary and sufficient conditions for a pattern of substitution effects to guarantee the existence of competitive equilibrium., Comment: 46 pages, 1 figure

Over the past several decades, prominent public management and policy scholars have repeatedly identified institutional analysis as a promising tool for empirical research, particularly for...

Smallholder agriculturalists employ a range of strategies to adapt to climate variability. These adaptive strategies include decisions to plant different seed varieties, changes to the array of cultivated crops, and shifts in planting dates. Smallholder access to irrigation water is crucial to the adoption of such strategies, and uncertainty of water availability may prove to be a stimulating force in a smallholder’s decision to adjust their on-farm practices. Within smallholder irrigation systems, attributes at multiple levels influence water availability and collective action, and in the process play a role in adaptation: community-level governance institutions may influence trust in others and the ability to overcome appropriation and provisioning dilemmas, and, at the household-level, the availability of irrigation water and socioeconomic and demographic factors may influence farmer willingness to take on the risk of altering their on-farm practices. In this study we investigate smallholder adaptation in Kenya from multiple levels. Specifically, we identify the role of household- and community-level characteristics in shaping smallholder experimentation with different seed varieties. Standard ordinary least squares and logistic regressions are constructed to assess the influence of these interactions on smallholder adaptation. We further discuss the ability of smallholders to respond to poor water provisioning. Among the study’s findings is evidence that smallholders are more willing to employ adaptive measures if they have a limited capacity to irrigate.

The electric sector has undergone a remarkable transition over the past several decades, witnessing dramatic changes in the range of technologies used to provide power to consumers, the diversity of actors that have a stake in the sector, and the regulatory institutions that structure governance. In this paper, we argue that the centralized, formal, quasi-judicial regulatory approach traditionally used to regulate utilities among U.S. states is ill-suited to manage the emergent transition toward increased use of distributed resources such as demand-side management. Indeed, as the use of distributed resources has grown, states have begun to develop formal and informal ways to meaningfully engage market participants and other stakeholders in regulatory decision making. We call this trend “distributed governance,” embodying the idea that the new paradigm for electricity regulation is no longer centralized, but rather is distributed among state, market, and civic participants. In this paper, we examine distributed governance within the context of U.S. states’ demand-side management policies and programs. Using regulatory documents from Public Utility Commissions across the U.S., interviews with electric sector stakeholders in two states, and literature from public policy and management scholars, we develop propositions about distributed governance for distributed resources in the electric sector.

The purpose of this article is to review and synthesize recent scholarship on stakeholder engagement in electric sector governance, placing research within a framework for understanding the role that stakeholders play in regulation and governance. Collaborative, multi-actor forums have developed to assist in the governance of electricity transmission and state-level clean energy activities, allowing stakeholders with divergent interests to help resolve political and technical challenges related to increased use of renewable and distributed electricity. The traditional approaches to electric sector regulation are ill-suited to address the opportunities and challenges facing the sector today. In response to changing conditions in the electric sector, many jurisdictions and regions have developed more flexible, cooperative, deliberative, and inclusive approaches to governance that encourage diverse stakeholders to work together to resolve emerging issues and coordinate between policy venues.

State renewable portfolio standard (RPS) mandates, competitive wholesale electricity markets, and cooperative regional transmission planning have all been identified as potential drivers of RE production. However, these factors are typically studied in isolation, and studies come to mixed conclusions about their actual effects on RE deployment. In this article, we a) use a novel “networks of action situations” (NAS) approach to examine the way that state RPS mandates, competitive markets, and regional transmission planning interact to jointly affect RE production; and b) ask whether these patterns differ across traditionally regulated and “deregulated” jurisdictions. We analyze and compare interactions between mandates, markets, and regional planning processes across two state-region dyads, both of which have achieved high levels of RE deployment but represent different institutional contexts. We find that RPS mandates are key drivers of RE deployment, but that these effects are realized through regional markets and planning processes. RPS mandates are similarly embedded in markets and networks in both cases with similar effects on RE production, but Minnesota's more traditional approach gives regulators greater authority over the type and location of RE production compared to Connecticut's more market-driven approach. Our analysis suggests that policy analysts should pay closer attention to the institutional environments in which policy instruments are embedded, and we offer several testable propositions about how mandate, market, and network interactions likely shape RE production.

We investigate (i) the impact of emission reduction policy on investment in polluting infrastructure, such as coal-fired power stations and (ii) optimal subsidies for “clean” alternatives with “learning” spillovers. We build a general theoretical model, and embed it in a fully calibrated integrated assessment model. Because emission reduction policy reduces investments in polluting assets, short-term emission reductions are enhanced—our “irreversibility effect”. Thus, “stranded assets” in this fuel-using sector have distinctive properties. We also provide a simple formula for how the optimal subsidy to deployment of a “clean” sector depends on its rate of “learning-by-doing” and on its socially-optimal growth. So, if the sector should grow faster for other reasons, its optimal subsidy is increased, showing that its optimal growth rate is faster still—our “acceleration effect”. Our calibrations show that, to limit global climate change to 2○C warming, investments in coal-fired power stations must end very soon. Considering second-best settings, we show that carbon taxes achieve stringent policy targets more efficiently, but subsidies to the “clean” sector deliver higher welfare, and are more efficient, when policy targets are more mild.

An Equivalence Theorem between geometric structures and utility functions allows new methods for understanding preferences. Our classification of valuations into “Demand Types” incorporates existing definitions (substitutes, complements, “strong substitutes,” etc.) and permits new ones. Our Unimodularity Theorem generalizes previous results about when competitive equilibrium exists for any set of agents whose valuations are all of a “demand type.” Contrary to popular belief, equilibrium is guaranteed for more classes of purely‐complements than of purely‐substitutes, preferences. Our Intersection Count Theorem checks equilibrium existence for combinations of agents with specific valuations by counting the intersection points of geometric objects. Applications include matching and coalition‐formation, and the “Product‐Mix Auction” introduced by the Bank of England in response to the financial crisis.

Why did the Ghanaian state go to such extraordinary lengths to facilitate the reliable broadcast of the World Cup in 2014? During a period of frequent power outages, Ghana swapped power with regional neighbours and directed major domestic industries to reduce production in order to allow Ghanaians to watch their national soccer team compete in the World Cup. This paper investigates the politics of the public service provision of electricity in Ghana. We focus on the short-term crisis during the 2014 World Cup to reveal the citizens' and politicians' expectations about electricity as a public good. Drawing on an analysis of archival documents, Ghanaian newspapers, and interviews with government, business, and NGO officials in the energy sector, we argue that the Ghanaian state historically has created the expectation of electricity as a right of national citizenship and explore how this intersects with competitive party politics today.