Place-Based Pathways to Proenvironmental Behavior: Empirical Evidence for a Conservation–Recreation Model     

Lincoln R. Larson  Caren B. Cooper  Richard C. Stedman  Daniel J. Decker  Ryan J. Gagnon 《社会与自然资源》2018,31(8):871-891

This study expands existing models of proenvironmental behavior (PEB) to examine the potentially important and interacting influences of nature-based recreation and sense of place on participation in conservation-oriented activities. We tested hypothesized relationships using a structural equation modeling approach that accounted for common behavioral antecedents within a sample of 1,124 nature-based recreationists and property owners in rural counties of New York, USA. We found that place attachment played an important role in strengthening connections between nature-based recreation and PEB. Birdwatching and hunting participation contributed independently and significantly to PEB, both directly and indirectly through effects on place meanings and place attachment. While birdwatching appeared to influence place attachment by impacting environmental place meanings, hunting exerted similar effects by affecting sociocultural place meanings. Ultimately, our synthesis results in the articulation of a comprehensive conservation–recreation model that could help researchers and practitioners identify and explore novel pathways to PEB.  相似文献   

Supernova bounds on neutrino radiative decays     

Lothar Oberauer  Caren Hagner

Georg Raffelt

Erich Rieger 《Astroparticle Physics》1993,1(4):377-386

The Solar Maximum Mission satellite did not record any γ-ray counts in excess of the background for a time interval of 223 s after the arrival of the first _e's from the supernova 1987A. On the basis of the original data we derive a new 3σ upper limit on the γ fluence for this period and derive improved bounds on the ν_i → ν_jγ and ν_T → ν_ee⁻e⁺γ radiative decay channels for neutrino masses up to the experimentally allowed value of around 30 MeV.  相似文献   

Forest carbon in North America: annual storage and emissions from British Columbia's harvest, 1965- 2065     

CC Dymond 《Carbon balance and management》2012,7(1):8

ABSTRACT: BACKGROUND: The default international accounting rules estimate the carbon emissions from forest products by assuming all harvest is immediately emitted to the atmosphere. This makes it difficult to assess the greenhouse gas (GHG) consequences of different forest management or manufacturing activities that maintain the storage of carbon. The Intergovernmental Panel on Climate Change (IPCC) addresses this issue by allowing other accounting methods. The objective of this paper is to provide a new model for estimating annual stock changes of carbon in harvested wood products (HWP). RESULTS: The model, British Columbia Harvested Wood Products version 1 (BC-HWPv1), estimates carbon stocks and fluxes for wood harvested in BC from 1965 to 2065, based on new parameters on local manufacturing, updated and new information for North America on consumption and disposal of wood and paper products, and updated parameters on methane management at landfills in the USA. Based on model results, reporting on emissions as they occur would substantially lower BC[RIGHT SINGLE QUOTATION MARK]s greenhouse gas inventory in 2010 from 48 Mt CO2 to 26 Mt CO2 because of the long-term forest carbon storage in-use and in the non-degradable material in landfills. In addition, if offset projects created under BC[RIGHT SINGLE QUOTATION MARK]s protocol reported 100 year cumulative emissions using the BC-HWPv1 the emissions would be lower by about 11%. CONCLUSIONS: This research showed that the IPCC default methods overestimate the emissions North America wood products. Future IPCC GHG accounting methods could include a lower emissions factor (e.g. 0.52) multiplied by the annual harvest, rather than the current multiplier of 1.0. The simulations demonstrated that the primary opportunities for climate change mitigation are in shifting from burning mill waste to using the wood for longer-lived products.  相似文献   

Nested structure of plankton communities from Chilean freshwaters   总被引：1，自引：1，他引：0  

Rodrigo Ramos-Jiliberto  J. Pablo Oyanedel  Caren Vega-Retter  Fernanda S. Valdovinos 《Limnologica》2009,39(4):319-324

1. Nestedness has been recognized as a characteristic pattern of community organization. In a nested metacommunity, species-poor sites are proper subsets of relatively richer sites, implying that the conservation of many poor habitats can be ineffective.

2. Here we compiled the last 30 years of published limnological research on Chilean lakes, in order to determine whether or not species distribution of freshwater plankton communities exhibit a nested structure, and which habitat features best explain the observed biogeographic order.

3. We built presence–absence matrices for diatoms, green algae, blue-green algae, cladocerans, copepods, rotifers, as well as for the grouped phytoplankton and zooplankton. For each matrix, we calculated their degree of nestedness and tested whether or not they differ from matrices assembled according to two alternative null models. From nestedness results, we identified a minimal set of lakes that contain 75% of the regional species pool. After that, we evaluated whether nestedness is maintained when the community structure is organized according to latitude, altitude, area and isolation of lakes.

4. Our analyses reveal that total phytoplankton, total zooplankton, as well as diatom, cladoceran, copepod, and rotifer assemblages of Chilean lakes are not randomly assembled but highly nested. Conversely, green and blue-green algae did not show a clear nested structure. A few sites (3–5) ranked by nestedness for each taxonomic group, covered 75% of the species pool. Finally, we found that surface area and isolation of lakes were the two variables more likely to affect nestedness.