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Browsing Gund Institute for Ecological Economics by Title

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  • Zencey, Eric (The North American ReviewUniversity of Northern Iowa, New York, NY., 2007
  • Erickson, Daniel L.; Lovell, Sarah Taylor; Mendez, V. Ernesto (Landscape and Urban Planning, 2011
      Throughout the world, urbanization is causing a loss of agricultural land as residential and commercial development expand. In Chittenden County, Vermont, U.S.A., this land use conversion has resulted in subdivision of farms into large residential parcels. Some of these residential parcels retain sizeable areas of undeveloped prime agricultural soil, yet the land is effectively removed from agricultural production. This study explored landowner willingness to enroll a portion of their land in a cooperative land management (CLM) scheme. Our results show support for embedding production agriculture and other cooperative land use options in residential parcels. Almost half of the respondents (45.6%) indicated they would enroll a portion of their land in a CLM program, while another 28.4% said "maybe". A cluster analysis partitioned the respondents into five clusters based on the following variables: percent agricultural land on parcel, parcel size, years in residence, and the population density of the town where the parcel is located. Willingness to participate in the CLM program and different land use options (livestock grazing, vegetables, fruit, field crops, biofuel, maple sugaring, wildflowers, medicinal plants, wildlife corridor, and recreational trails) varied across the clusters. A cluster containing a high percentage of agricultural land ("farms") had the highest support for production agriculture options, while a cluster of long term residents (old timers) had the lowest. These results are encouraging for farmers seeking access to affordable farmland and for planning efforts seeking increased regional landscape multifunctionality. (C) 2011 Elsevier B.V. All rights reserved.
  • Ricketts, T. H.; Regetz, J.; Steffan-Dewenter, I.; Cunningham, S. A.; Kremen, C.; Bogdanski, A.; Gemmill-Herren, B.; Greenleaf, S. S.; Klein, A. M.; Mayfield, M. M.; Morandin, L. A.; Ochieng, A.; Potts, S. G.; Viana, B. F. (Ecology Letters, 2008
      Pollination by bees and other animals increases the size, quality, or stability of harvests for 70% of leading global crops. Because native species pollinate many of these crops effectively, conserving habitats for wild pollinators within agricultural landscapes can help maintain pollination services. Using hierarchical Bayesian techniques, we synthesize the results of 23 studies – representing 16 crops on five continents – to estimate the general relationship between pollination services and distance from natural or semi-natural habitats. We find strong exponential declines in both pollinator richness and native visitation rate. Visitation rate declines more steeply, dropping to half of its maximum at 0.6 km from natural habitat, compared to 1.5 km for richness. Evidence of general decline in fruit and seed set – variables that directly affect yields – is less clear. Visitation rate drops more steeply in tropical compared with temperate regions, and slightly more steeply for social compared with solitary bees. Tropical crops pollinated primarily by social bees may therefore be most susceptible to pollination failure from habitat loss. Quantifying these general relationships can help predict consequences of land use change on pollinator communities and crop productivity, and can inform landscape conservation efforts that balance the needs of native species and people.
  • Windhausen, L. J.; Braun, D. C.; Wang, D. (Kluwer Academic/Plenum Publishers, New York, NY.New York, NY, 2004
      We used a landscape scale approach to examine phosphorus retention in wetlands of the LaPlatte River basin (13,723 ha), Vermont. Total phosphorus (TP) export from 15 study catchments (149-1,396 ha) was measured on 18 dates, representing a range in seasons and hydrologic conditions. Multiple regression models were developed to relate TP export to 14 possible explanatory variables based on land cover/use, quantified using a geographic information system. Most wetland variables had significant (p < 0.10) negative relationships with TP export on at least 1 date. These relationships were strongest on 2 spring snowmelt events, when 31% of the annual TP export from the LaPlatte River basin occurred. Overall, the percentage of nonagricultural poorly and very poorly drained soils was the best representation of phosphorus sinks in the study catchments. Identifying lands with poorly drained soils and no known sources of phosphorus may be a more functional and simpler method of delineating P sinks in the landscape than identifying wetlands using jurisdictional definitions.
  • Zia, A. (Sustainability, 2012
      Global climate change, especially the phenomena of global warming, is expected to increase the intensity of land-falling hurricanes. Societal adaptation is needed to reduce vulnerability from increasingly intense hurricanes. This study quantifies the adaptation effects of potentially policy driven caps on housing densities and agricultural cover in coastal (and adjacent inland) areas vulnerable to hurricane damages in the Atlantic and Gulf Coastal regions of the U.S. Time series regressions, especially Prais-Winston and Autoregressive Moving Average (ARMA) models, are estimated to forecast the economic impacts of hurricanes of varying intensity, given that various patterns of land use emerge in the Atlantic and Gulf coastal states of the U.S. The Prais-Winston and ARMA models use observed time series data from 1900 to 2005 for inflation adjusted hurricane damages and socio-economic and land-use data in the coastal or inland regions where hurricanes caused those damages. The results from this study provide evidence that increases in housing density and agricultural cover cause significant rise in the de-trended inflation-adjusted damages. Further, higher intensity and frequency of land-falling hurricanes also significantly increase the economic damages. The evidence from this study implies that a medium to long term land use adaptation in the form of capping housing density and agricultural cover in the coastal (and adjacent inland) states can significantly reduce economic damages from intense hurricanes. Future studies must compare the benefits of such land use adaptation policies against the costs of development controls implied in housing density caps and agricultural land cover reductions.
  • Trudel, R. E.; Bomblies, A. (Parasites & VectorsParasites Vectors, 2011
      Background: Synthetic insecticides are employed in the widely-used currently favored malaria control techniques involving indoor residual spraying and treated bednets. These methods have repeatedly proven to be highly effective at reducing malaria incidence and prevalence. However, rapidly emerging mosquito resistance to the chemicals and logistical problems in transporting supplies to remote locations threaten the long-term sustainability of these techniques. Chinaberry (Melia azederach) extracts have been shown to be effective growth-inhibiting larvicides against several insects. Because several active chemicals in the trees' seeds have insecticidal properties, the emergence of resistance is unlikely. Here, we investigate the feasibility of Chinaberry as a locally available, low-cost sustainable insecticide that can aid in controlling malaria. Chinaberry fruits were collected from Asendabo, Ethiopia. The seeds were removed from the fruits, dried and crushed into a powder. From developmental habitats in the same village, Anopheles arabiensis larvae were collected and placed into laboratory containers. Chinaberry seed powder was added to the larval containers at three treatment levels: 5 g m(-2), 10 g m(-2) and 20 g m(-2), with 100 individual larvae in each treatment level and a control. The containers were monitored daily and larvae, pupae and adult mosquitoes were counted. This experimental procedure was replicated three times. Results: Chinaberry seed powder caused an inhibition of emergence of (3% at the 5 g m(-2) treatment level, and 100% inhibition of emergence at the two higher treatment levels. The Chinaberry had a highly statistically significant larvicidal effect at all treatment levels (chi(2) = 184, 184, and 155 for 5 g m(-2), 10 g m(-2) and 20 g m(-2), respectively; p < 0.0001 in all cases). In addition, estimates suggest that sufficient Chinaberry seed exists in Asendabo to treat developmental habitat for the duration of the rainy season and support a field trial. Conclusions: Chinaberry seed is a very potent growth-inhibiting larvicide against the major African malaria vector An. arabiensis. The seed could provide a sustainable additional malaria vector control tool that can be used where the tree is abundant and where An. arabiensis is a dominant vector. Based on these results, a future village-scale field trial using the technique is warranted.
  • Keeton, W. S.; Whitman, A. A.; McGee, G. C.; Goodale, C. L. (Forest Science, 2011
      Managing the contribution of forest ecosystems to global carbon cycles requires accurate predictions of biomass dynamics in relation to stand development. Our study evaluated competing hypotheses regarding late-successional biomass dynamics in northern hardwood-conifer forests using a data set spanning the northeastern United States, including 48 mature and 46 old-growth stands. Continuous data on dominant tree ages were available for 29 of these and were used as an indicator of stand development. Aboveground live biomass was significantly (P < 0.001) different between mature (195 Mg/ha) and old-growth (266 Mg/ha) sites. Aboveground biomass was positively (P < 0.001) and logarithmically correlated with dominant tree age; this held for live trees (r(2) = 0.52), standing dead trees (r(2) = 0.36), total trees (r(2) = 0.63), and downed woody debris (r(2) = 0.24). In a Classification and Regression Tree analysis, stand age class was the strongest predictor of biomass, but ecoregion and percent conifer accounted for similar to 25-33% of intraregional variability. Biomass approached maximum values in stands with dominant tree ages of similar to 350-400 years. Our results support the hypothesis that aboveground biomass can accumulate very late into succession in northern hardwood-conifer forests, recognizing that early declines are also possible in secondary forests as reported previously. Empirical studies suggest a high degree of variability in biomass development pathways and these may differ from theoretical predictions. Primary forest systems, especially those prone to partial disturbances, may have different biomass dynamics compared with those of secondary forests. These differences have important implications for both the quantity and temporal dynamics of carbon storage in old-growth and recovering secondary forests. FOR. SCI 57(6):489-505.
  • Stovall, J. P.; Keeton, W. S.; Kraft, C. E. (Canadian Journal of Forest Research-Revue Canadienne De Recherche Forestiere, 2009
      Late-successional riparian forests often regulate autotrophic microhabitats in low-order streams through shading provided by canopies. However, few studies have linked forest structure with periphyton microhabitat in adjoining streams. Our hypotheses were that (1) the heterogeneous horizontal structure in old-growth forests creates more spatially variable below-canopy light environments compared with mature forests and (2) site-specific light availability over streams correlates with spatial distributions of periphyton microhabitat. We surveyed 15 low-order stream reaches in late-successional northern hardwood-hem lock forests in the Adirondack Mountains of New York, USA. We measured forest structure and the below-canopy light environment at all reaches and the periphyton chlorophyll a concentration on artificial substrates in eight reaches. While stand age was not statistically significant, multivariate models of horizontal forest structure (e.g., gap distribution) and topography showed strong relationships (R(2) > 0.70) with the below-canopy light environment across all late-successional forests. Furthermore, metrics of below-canopy light availability explained a small but statistically significant proportion of the variation in chlorophyll a concentration. This variation in chlorophyll a indicates that complex late-successional riparian forests, both mature and old-growth, create a mosaic of heterotrophic (shaded) and autotrophic (lighted) microhabitats along low-order streams. These results reveal important and previously unrecognized links between stream habitat heterogeneity and the horizontal heterogeneous late-successional forest structure.
  • Negra, C.; Wollenberg, E. (CGIAR Research Program on Climate Change, Agriculture and Food Security, Copenhagen, Denmark.Copenhagen, Denmark, 2011
  • Bormann, B. T.; Keller, C. K.; Wang, D.; Bormann, F. H. (Ecosystems, 2002
      In their review of 24 studies of forest nitrogen (N) budgets, Binkley and others (2000) found that only one of them supported the conclusion that an N accumulation of more than 25 kg N ha(-1) y(-1) is possible without known symbiotic N-2-fixing plants. They contended that, given how well the N cycle is known, new N accumulation pathways are unlikely. They also concluded that the Hubbard Brook sandbox study (Bormann and others 1993) was insufficiently replicated and had low precision in vegetation and soil estimates. Here we reevaluate and extend the sandbox analysis and place the findings in a broader context. Using multiple methods of estimating vegetation N accumulation in pine sandboxes, we arrived at results that differed from the reported rates but still strongly supported large biomass N accumulation. The original study's conclusions about soil N changes were strengthened when new evidence showed that N accumulated in lower horizons and that the sandboxes were successfully homogenized at the beginning of the experiment. Unexplained ecosystem N accumulation ranged from about 40 to 150 kg ha(-1) y(-1), with 95% confidence intervals that did not include zero. No evidence was found that could balance the sandbox ecosystem N budgets without adding unexplained N. Unreplicated experiments, such as the sandboxes, can explore the possibility that N can accumulate in ways not explainable by mass balance analysis, but they cannot quantify the frequency and extent of the phenomenon. New studies should combine substantive microbiological, mass balance, and process research using multiple direct measures of N-2 fixation.
  • Roman, J.; Dunphy-Daly, M. M.; Johnston, D. W.; Read, A. J. (Trends in Ecology & Evolution, 2015
      Biologists and policymakers are accustomed to managing species in decline, but for the first time in generations they are also encountering recovering populations of ocean predators. Many citizens perceive these species as invaders and conflicts are increasing. It is time to celebrate these hard-earned successes and lift baselines for recovering species.
  • Farber, S.; Costanza, R.; Childers, D. L.; Erickson, J.; Gross, K.; Grove, M.; Hopkinson, C. S.; Kahn, J.; Pincetl, S.; Troy, A.; Warren, P.; Wilson, M. (Bioscience, 2006
      This article outlines an approach, based on ecosystem services, for assessing the trade-offs inherent in managing humans embedded in ecological systems. Evaluating these trade-offs requires an understanding of the biophysical magnitudes of the changes in ecosystem services that result from human actions, and of the impact of these changes on human welfare. We summarize the state of the art of ecosystem services-based management and the information needs for applying it. Three case studies of Long Term Ecological Research (LTER) sites-coastal, urban, and agricultural-illustrate the usefulness, information needs, quantification possibilities, and methods for this approach. One example of the application of this approach, with rigorously established service changes and valuations taken front the literature, is used to illustrate the potential for full economic valuation of several agricultural landscape management options, including managing for water quality biodiversity, and crop productivity.
  • Yamana, T. K.; Bomblies, A.; Laminou, I. M.; Duchemin, J. B.; Eltahir, E. A. B. (Parasites & VectorsParasites Vectors, 2013
      Background: Individuals continuously exposed to malaria gradually acquire immunity that protects from severe disease and high levels of parasitization. Acquired immunity has been incorporated into numerous models of malaria transmission of varying levels of complexity (e. g. Bull World Health Organ 50: 347, 1974; Am J Trop Med Hyg 75: 19, 2006; Math Biosci 90:385-396, 1988). Most such models require prescribing inputs of mosquito biting rates or other entomological or epidemiological information. Here, we present a model with a novel structure that uses environmental controls of mosquito population dynamics to simulate the mosquito biting rates, malaria prevalence as well as variability in protective immunity of the population. Methods: A simple model of acquired immunity to malaria is presented and tested within the framework of the Hydrology, Entomology and Malaria Transmission Simulator (HYDREMATS), a coupled hydrology and agent-based entomology model. The combined model uses environmental data including rainfall, temperature, and topography to simulate malaria prevalence and level of acquired immunity in the human population. The model is used to demonstrate the effect of acquired immunity on malaria prevalence in two Niger villages that are hydrologically and entomologically very different. Simulations are conducted for the year 2006 and compared to malaria prevalence observations collected from the two villages. Results: Blood smear samples from children show no clear difference in malaria prevalence between the two villages despite pronounced differences in observed mosquito abundance. The similarity in prevalence is attributed to the moderating effect of acquired immunity, which depends on prior exposure to the parasite through infectious bites - and thus the hydrologically determined mosquito abundance. Modelling the level of acquired immunity can affect village vulnerability to climatic anomalies. Conclusions: The model presented has a novel structure constituting a mechanistic link between spatial and temporal environmental variability and village-scale malaria transmission. Incorporating acquired immunity into the model has allowed simulation of prevalence in the two villages, and isolation of the effects of acquired immunity in dampening the difference in prevalence between the two villages. Without these effects, the difference in prevalence between the two villages would have been significantly larger in response to the large differences in mosquito populations and the associated biting rates.
  • Mwakalila, S.; Burgess, N.; Ricketts, T.; Olwero, N.; Swetnam, R. D.; Mbilinyi, B. P.; Marchant, R.; Mtalo, F.; White, S.; Munishi, P. K.; Marshall, A.; Malimbwi, R. E.; Smith, C. M.; Jambiya, G.; Madoffe, S.; Fisher, B.; Kajembe, G.; Morse-Jones, S.; Kulindwa, K.; Green, J. M. H.; Balmford, A. (2009
  • Wollenberg, E.; Colchester, M.; Mbugua, G.; Griffiths, T. (International Forestry Review, 2006
      International networks in community forestry face challenges in linking with local social movements. We examine four efforts of international networks to overcome these challenges and better link with local people in Peru, Brazil, India and Kenya. The examples demonstrate that the networks created effective links by making funds available for meetings and local data collection; providing international analyses that helped people understand their own situation better; sharing strategies for media, policy and letter campaigns; helping to disseminate information about local people's priorities, providing independent assessments and building local people's confidence. Efforts to improve communications technologies required a better understanding of local conditions. Networks will be more relevant to local movements to the extent that they are regularly active at the local level, can respond flexibly to local needs and small-scale events, and work with an array of national partners. The effectiveness of networks in carrying out these tasks may require a careful balance between linking to versus working at the local level.
  • Roman, J. (Harvard University Press , Cambridge, MA.Cambridge, MA, 2011
      The first listed species to make headlines after the Endangered Species Act was passed in 1973 was the snail darter, a three-inch fish that stood in the way of a massive dam on the Little Tennessee River. When the Supreme Court sided with the darter, Congress changed the rules. The dam was built, the river stopped flowing, and the snail darter went extinct on the Little Tennessee, though it survived in other waterways. A young Al Gore voted for the dam; freshman congressman Newt Gingrich voted for the fish. A lot has changed since the 1970s, and Joe Roman helps us understand why we should all be happy that this sweeping law is alive and well today. More than a general history of endangered species protection, Listed is a tale of threatened species in the wild—from the whooping crane and North Atlantic right whale to the purple bankclimber, a freshwater mussel tangled up in a water war with Atlanta—and the people working to save them. Employing methods from the new field of ecological economics, Roman challenges the widely held belief that protecting biodiversity is too costly. And with engaging directness, he explains how preserving biodiversity can help economies and communities thrive. Above all, he shows why the extinction of species matters to us personally—to our health and safety, our prosperity, and our joy in nature.
  • Mendez, V. E.; Castro-Tanzi, S.; Goodall, K.; Morris, K. S.; Bacon, C. M.; Laderach, P.; Morris, W. B.; Georgeoglou-Laxalde, M. U. (Routledge, New York, NY.New York, NY, 2012
  • Loh, J.; Green, R. E.; Ricketts, T.; Lamoreux, J.; Jenkins, M.; Kapos, V.; Randers, J. (Philosophical Transactions of the Royal Society B-Biological Sciences, 2005
      The Living Planet Index was developed to measure the changing state of the world's biodiversity over time. It uses time-series data to calculate average rates of change in a large number of populations of terrestrial, freshwater and marine vertebrate species. The dataset contains about 3000 population time series for over 1100 species. Two methods of calculating the index are outlined: the chain method and a method based on linear modelling of log-transformed data. The dataset is analysed to compare the relative representation of biogeographic realms, ecoregional biomes, threat status and taxonomic groups among species contributing to the index. The two methods show very similar results: terrestrial species declined on average by 25% from 1970 to 2000. Birds and mammals are over-represented in comparison with other vertebrate classes, and temperate species are over-represented compared with tropical species, but there is little difference in representation between threatened and non-threatened species. Some of the problems arising from over-representation are reduced by the way in which the index is calculated. It may be possible to reduce this further by post-stratification and weighting, but new information would first need to be collected for data-poor classes, realms and biomes.
  • Todd, John (Nature’s Operating Instructions: The true biotechnologies. Sierra Club Books, San Francisco, 2004
  • Stevens, L.; Rizzo, D. M. (Ecological Complexity, 2008
      Spatial and temporal variability in the application of biological control agents such as parasites or pathogenic bacteria can cause the evolution of resistance in pest organisms. Because biocontrol will be more effective if organisms are not resistant, it is desirable to examine the evolution of resistance under different application strategies. We present a computational method that integrates a genetic algorithm with experimental data for predicting when local populations are likely to evolve resistance to biocontrol pathogens. The model incorporates parameters that can be varied as part of pest control measures such as the distribution and severity of the biocontrol agent (e.g., pathogenic fungi). The model predicts the evolution of pathogen defense as well as indirect selection on several aspects of the organism's genetic system. Our results show that both variability of selection within populations as well as mean differences among populations are important in the evolution of defenses against biocontrol pathogens. The mean defense is changed through the pest organism's genotype and the variance is affected by components of the genetic system, namely, the resiliency, recombination rate and number of genes. The data-driven model incorporates experimental data on pathogen susceptibility and the cost of defense. The results suggest that spatial variability rather than uniform application of biological control will limit the evolution of resistance in pest organisms. (c) 2008 Elsevier B.V. All rights reserved.

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