bluuebunny/crossref_metadata_2025_split huggingface dataset:
Prioritizing land management efforts at a landscape scale: a case study using prescribed fire inWisconsin
Authors: Hmielowski Tracy L. , Carter Sarah K. , Spaul Hannah , Helmers David , Radeloff Volker C. , Zedler Paul 
Published: May 2016

AbstractOne challenge in the effort to conserve biodiversity is identifying where to prioritize resources for active land management. Cost–benefit analyses have been used successfully as a conservation tool to identify sites that provide the greatest conservation benefit per unit cost. Our goal was to apply cost–benefit analysis to the question of how to prioritize land management efforts, in our case the application of prescribed fire to natural landscapes in Wisconsin,USA. We quantified and mapped frequently burned communities and prioritized management units based on a suite of indices that captured ecological benefits, management effort, and the feasibility of successful long‐term management actions. Data for these indices came fromLANDFIRE, Wisconsin's Wildlife Action Plan, and a nationwide wildland–urban interface assessment. We found that the majority of frequently burned vegetation types occurred in the southern portion of the state. However, the highest priority areas for applying prescribed fire occurred in the central, northwest, and northeast portion of the state where frequently burned vegetation patches were larger and where identified areas of high biological importance area occurred. Although our focus was on the use of prescribed fire in Wisconsin, our methods can be adapted to prioritize other land management activities. Such prioritization is necessary to achieve the greatest possible benefits from limited funding for land management actions, and our results show that it is feasible at scales that are relevant for land management decisions.
Invasiveness of plant pathogens depends on the spatial scale of host distribution
Authors: Mikaberidze Alexey , Mundt Christopher C. , Bonhoeffer Sebastian 
Published: May 2016

AbstractPlant diseases often cause serious yield losses in agriculture. A pathogen’s invasiveness can be quantified by the basic reproductive number,R0. Since pathogen transmission between host plants depends on the spatial separation between them,R0is strongly influenced by the spatial scale of the host distribution.We present a proof of principle of a novel approach to estimate the basic reproductive number,R0, of plant pathogens as a function of the size of a field planted with crops and its aspect ratio. This general approach is based on a spatially explicit population dynamical model. The basic reproductive number was found to increase with the field size at small field sizes and to saturate to a constant value at large field sizes. It reaches a maximum in square fields and decreases as the field becomes elongated. This pattern appears to be quite general: it holds for dispersal kernels that decrease exponentially or faster, as well as for fat‐tailed dispersal kernels that decrease slower than exponential (i.e., power‐law kernels).We used this approach to estimateR0in wheat stripe rust (an important disease caused byPuccinia striiformis), where we inferred both the transmission rates and the dispersal kernels from the measurements of disease gradients. For the two largest datasets, we estimatedR0ofP. striiformisin the limit of large fields to be of the order of 30. We found that the spatial extent over whichR0changes strongly is quite fine‐scaled (about 30 m of the linear extension of the field). Our results indicate that in order to optimize the spatial scale of deployment of fungicides or host resistances, the adjustments should be made at a fine spatial scale. We also demonstrated how the knowledge of the spatial dependence ofR0can improve recommendations with regard to fungicide treatment.
Trade‐offs in water and carbon ecosystem services with land‐use changes in grasslands
Authors: Kim John H. , Jobbágy Esteban G. , Jackson Robert B. 
Published: May 2016

AbstractIncreasing pressures for food, fiber, and fuel continue to drive global land‐use changes. Efforts to optimize ecosystem services under alternative land uses are often hampered by the complex interactions and trade‐offs among them. We examined the effects of land‐use changes on ecosystem carbon storage and groundwater recharge in grasslands of Argentina and the United States to (1) understand the relationships between both services, (2) predict their responses to vegetation shifts across environmental gradients, and (3) explore how market or policy incentives for ecosystem services could affect land‐use changes. A trade‐off of ecosystem services was evident in most cases, with woody encroachment increasing carbon storage (+29 Mg C/ha) but decreasing groundwater recharge (−7.3 mm/yr) and conversions to rain‐fed cultivation driving opposite changes (−32 Mg C/ha vs. +13 mm/yr). In contrast, crops irrigated with ground water tended to reduce both services compared to the natural grasslands they replaced. Combining economic values of the agricultural products together with the services, we highlight potentials for relatively modest financial incentives for ecosystem services to abate land‐use changes and for incentives for carbon to drive land‐use decisions over those of water. Our findings also identify key opportunities and caveats for some win–win and lose–lose land‐use changes for more integrative and sustainable strategies for land management.
Prioritizing ecological restoration among sites in multi‐stressor landscapes
Authors: Neeson Thomas M. , Smith Sigrid D. P. , Allan J. David , McIntyre Peter B. 
Published: May 2016

AbstractMost ecosystems are impacted by multiple local and long‐distance stressors, many of which interact in complex ways. We present a framework for prioritizing ecological restoration efforts among sites in multi‐stressor landscapes. Using a simple model, we show that both the economic and sociopolitical costs of restoration will typically be lower at sites with a relatively small number of severe problems than at sites with numerous lesser problems. Based on these results, we propose using cumulative stress and evenness of stressor impact as complementary indices that together reflect key challenges of restoring a site to improved condition. To illustrate this approach, we analyze stressor evenness across the world's rivers and the Laurentian Great Lakes. This exploration reveals that evenness and cumulative stress are decoupled, enabling selection of sites where remediating a modest number of high‐intensity stressors could substantially reduce cumulative stress. Just as species richness and species evenness are fundamental axes of biological diversity, we argue that cumulative stress and stressor evenness constitute fundamental axes for identifying restoration opportunities in multi‐stressor landscapes. Our results highlight opportunities to boost restoration efficiency through strategic use of multi‐stressor datasets to identify sites that maximize ecological response per stressor remediated. This prioritization framework can also be expanded to account for the feasibility of remediation and the expected societal benefits of restoration projects.
The cost and feasibility of marine coastal restoration
Authors: Bayraktarov Elisa , Saunders Megan I. , Abdullah Sabah , Mills Morena , Beher Jutta , Possingham Hugh P. , Mumby Peter J. , Lovelock Catherine E. 
Published: May 2016

AbstractLand‐use change in the coastal zone has led to worldwide degradation of marine coastal ecosystems and a loss of the goods and services they provide. Restoration is the process of assisting the recovery of an ecosystem that has been degraded, damaged, or destroyed and is critical for habitats where natural recovery is hindered. Uncertainties about restoration cost and feasibility can impede decisions on whether, what, how, where, and how much to restore. Here, we perform a synthesis of 235 studies with 954 observations from restoration or rehabilitation projects of coral reefs, seagrass, mangroves, saltmarshes, and oyster reefs worldwide, and evaluate cost, survival of restored organisms, project duration, area, and techniques applied. Findings showed that while the median and average reported costs for restoration of one hectare of marine coastal habitat were around US$80 000 (2010) and US$1 600 000 (2010), respectively, the real total costs (median) are likely to be two to four times higher. Coral reefs and seagrass were among the most expensive ecosystems to restore. Mangrove restoration projects were typically the largest and the least expensive per hectare. Most marine coastal restoration projects were conducted in Australia, Europe, andUSA, while total restoration costs were significantly (up to 30 times) cheaper in countries with developing economies. Community‐ or volunteer‐based marine restoration projects usually have lower costs. Median survival of restored marine and coastal organisms, often assessed only within the first one to two years after restoration, was highest for saltmarshes (64.8%) and coral reefs (64.5%) and lowest for seagrass (38.0%). However, success rates reported in the scientific literature could be biased towards publishing successes rather than failures. The majority of restoration projects were short‐lived and seldom reported monitoring costs. Restoration success depended primarily on the ecosystem, site selection, and techniques applied rather than on money spent. We need enhanced investment in both improving restoration practices and large‐scale restoration.
Dynamic optimal foraging theory explains vertical migrations of Bigeye tuna
Authors: Thygesen Uffe H. , Sommer Lene , Evans Karen , Patterson Toby A. 
Published: May 2016

AbstractBigeye tuna are known for remarkable daytime vertical migrations between deep water, where food is abundant but the water is cold, and the surface, where water is warm but food is relatively scarce. Here we investigate if these dive patterns can be explained by dynamic optimal foraging theory, where the tuna maximizes its energy harvest rate. We assume that foraging efficiency increases with body temperature, so that the vertical migrations are thermoregulatory. The tuna's state is characterized by its mean body temperature and depth, and we solve the optimization problem numerically using dynamic programming. With little calibration of model parameters, our results are consistent with observed data on vertical movement: we find that small tuna should display constant‐depth strategies while large tuna should display vertical migrations. The analysis supports the hypothesis that the tuna behaves such as to maximize its energy gains. The model therefore provides insight into the processes underlying observed behavioral patterns and allows generating predictions of foraging behavior in unobserved environments.
Increased stem density and competition may diminish the positive effects of warming at alpine treeline
Authors: Wang Yafeng , Pederson Neil , Ellison Aaron M. , Buckley Hannah L. , Case Bradley S. , Liang Eryuan , Julio Camarero J. 
Published: May 2016

AbstractThe most widespread response to global warming among alpine treeline ecotones is not an upward shift, but an increase in tree density. However, the impact of increasing density on interactions among trees at treeline is not well understood. Here, we test if treeline densification induced by climatic warming leads to increasing intraspecific competition. We mapped and measured the size and age of Smith fir trees growing in two treelines located in the southeastern Tibetan Plateau. We used spatial point‐pattern and codispersion analyses to describe the spatial association and covariation among seedlings, juveniles, and adults grouped in 30‐yr age classes from the 1860s to the present. Effects of competition on tree height and regeneration were inferred from bivariate mark‐correlations. Since the 1950s, a rapid densification occurred at both sites in response to climatic warming. Competition between adults and juveniles or seedlings at small scales intensified as density increased. Encroachment negatively affected height growth and further reduced recruitment around mature trees. We infer that tree recruitment at the studied treelines was more cold‐limited prior to 1950 and shifted to a less temperature‐constrained regime in response to climatic warming. Therefore, the ongoing densification and encroachment of alpine treelines could alter the way climate drives their transitions toward subalpine forests.
Competitive release and outbreaks of non‐target pests associated with transgenic Bt cotton
Authors: Zeilinger Adam R. , Olson Dawn M. , Andow David A. 
Published: May 2016

AbstractThe adoption of transgenic Bt cotton has, in some cases, led to environmental and economic benefits through reduced insecticide use. However, the distribution of these benefits and associated risks among cotton growers and cotton‐growing regions has been uneven due in part to outbreaks of non‐target or secondary pests, thereby requiring the continued use of synthetic insecticides. In the southeastern USA, Bt cotton adoption has resulted in increased abundance of and damage from stink bug pests, Euschistus servus and Nezara viridula (Heteroptera: Pentatomidae). While the impact of increased stink bug abundance has been well‐documented, the causes have remained unclear. We hypothesize that release from competition with Bt‐susceptible target pests may drive stink bug outbreaks in Bt cotton. We first examined the evidence for competitive release of stink bugs through meta‐analysis of previous studies. We then experimentally tested if herbivory by Bt‐susceptible Helicoverpa zea increases stink bug leaving rates and deters oviposition on non‐Bt cotton. Consistent with previous studies, we found differences in leaving rates only for E. servus, but we found that both species strongly avoided ovipositing on H. zea‐damaged plants. Considering all available evidence, competitive release of stink bug populations in Bt cotton likely contributes to outbreaks, though the relative importance of competitive release remains an open question. Ecological risk assessments of Bt crops and other transgenic insecticidal crops would benefit from greater understanding of the ecological mechanisms underlying non‐target pest outbreaks and greater attention to indirect ecological effects more broadly.
Spatial processes structuring riparian plant communities in agroecosystems: implications for restoration
Authors: Bourgeois Bérenger , González Eduardo , Vanasse Anne , Aubin Isabelle , Poulin Monique 
Published: May 2016

AbstractThe disruption of hydrological connectivity by human activities such as flood regulation or land‐use changes strongly impacts riparian plant communities. However, landscape‐scale processes have generally been neglected in riparian restoration projects as opposed to local conditions, even though such processes might largely influence community recovery. We surveyed plant composition of field edges and riverbanks in 51 riparian zones restored by tree planting (565 1‐m2 plots) within two agricultural watersheds in southeastern Québec, Canada. Once the effects of environmental variables (hydrology, soil, agriculture, landscape, restoration) were partialled out, three models of spatial autocorrelation based on Moran's eigenvector maps and asymmetric eigenvector maps were compared to quantify the pathways and direction of the spatial processes structuring riparian communities. The ecological mechanisms underlying predominant spatial processes were then assessed by regression trees linking species response to spatial gradients to seed and morphological traits. The structure of riparian communities was predominantly related to unidirectional spatial gradients from upstream to downstream along watercourses, which contributed more to species composition than bidirectional gradients along watercourses or overland. Plant traits selected by regression trees explained 22% of species response to unidirectional upstream–downstream gradients in field edges and 24% in riverbanks, and predominantly corresponded to seed traits rather than morphological traits of the adult plants. Our study showed that even in agriculturally open landscapes, water flow remains a major force structuring spatially riparian plant communities by filtering species according to their seed traits, thereby suggesting long‐distance dispersal as a predominant process. Preserving hydrological connectivity at the watershed‐scale and restoring riparian plant communities from upstream to downstream should be encouraged to improve the ecological integrity of rivers running through agricultural landscapes.
Combining statistical inference and decisions in ecology
Authors: Williams Perry J. , Hooten Mevin B. 
Published: May 2016

AbstractStatistical decision theory (SDT) is a sub‐field of decision theory that formally incorporates statistical investigation into a decision‐theoretic framework to account for uncertainties in a decision problem. SDT provides a unifying analysis of three types of information: statistical results from a data set, knowledge of the consequences of potential choices (i.e., loss), and prior beliefs about a system. SDT links the theoretical development of a large body of statistical methods, including point estimation, hypothesis testing, and confidence interval estimation. The theory and application of SDT have mainly been developed and published in the fields of mathematics, statistics, operations research, and other decision sciences, but have had limited exposure in ecology. Thus, we provide an introduction to SDT for ecologists and describe its utility for linking the conventionally separate tasks of statistical investigation and decision making in a single framework. We describe the basic framework of both Bayesian and frequentist SDT, its traditional use in statistics, and discuss its application to decision problems that occur in ecology. We demonstrate SDT with two types of decisions: Bayesian point estimation and an applied management problem of selecting a prescribed fire rotation for managing a grassland bird species. Central to SDT, and decision theory in general, are loss functions. Thus, we also provide basic guidance and references for constructing loss functions for an SDT problem.
Carbon‐equivalent metrics for albedo changes in land management contexts: relevance of the time dimension
Authors: Bright Ryan M. , Bogren Wiley , Bernier Pierre , Astrup Rasmus 
Published: May 2016

AbstractSurface albedo is an important physical property by which the land surface regulates climate. A wide and growing body of literature suggests that failing to account for surface albedo can result in suboptimal or even counterproductive climate‐motivated policies of the land‐based sectors. As such, albedo changes are increasingly included in climate impact assessments of forestry and other land sector projects through conversion of radiative forcings into carbon or carbon dioxide equivalents. However, the prevailing methodology does not sufficiently accommodate dynamic albedo changes on land or CO2 in the atmosphere. We present two new metrics designed to address these deficiencies, referring to them as the time‐dependent emissions equivalent and the time‐independent emissions equivalent of albedo changes. We demonstrate their application in various land management contexts and discuss their merits and uncertainties.
Within‐ and among‐population variation in vital rates and population dynamics in a variable environment
Authors: Vincenzi Simone , Mangel Marc , Jesensˇek Dusˇan , Garza John C. , Crivelli Alain J. 
Published: May 2016

AbstractUnderstanding the causes of within‐ and among‐population differences in vital rates, life histories, and population dynamics is a central topic in ecology. To understand how within‐ and among‐population variation emerges, we need long‐term studies that include episodic events and contrasting environmental conditions, data to characterize individual and shared variation, and statistical models that can tease apart shared and individual contribution to the observed variation. We used long‐term tag–recapture data to investigate and estimate within‐ and among‐population differences in vital rates, life histories, and population dynamics of marble troutSalmo marmoratus, an endemic freshwater salmonid with a narrow range. Only ten populations of pure marble trout persist in headwaters of Alpine rivers in western Slovenia. Marble trout populations are also threatened by floods and landslides, which have already caused the extinction of two populations in recent years. We estimated and determined causes of variation in growth, survival, and recruitment both within and among populations, and evaluated trade‐offs between them. Specifically, we estimated the responses of these traits to variation in water temperature, density, sex, early life conditions, and extreme events. We found that the effects of population density on traits were mostly limited to the early stages of life and that growth trajectories were established early in life. We found no clear effects of water temperature on vital rates. Population density varied over time, with flash floods and debris flows causing massive mortalities (>55% decrease in survival with respect to years with no floods) and threatening population persistence. Apart from flood events, variation in population density within streams was largely determined by variation in recruitment, with survival of older fish being relatively constant over time within populations, but substantially different among populations. Marble trout show a fast to slow continuum of life histories, with slow growth associated with higher survival at the population level, possibly determined by food conditions and age at maturity. Our work provides unprecedented insight into the causes of variation in vital rates, life histories, and population dynamics in an endemic species that is teetering on the edge of extinction.