Thirty years of vegetation change in the coastal Santa Cruz Mountains of Northern California detected using landsat satellite image analysis

The Santa Cruz Mountains is a coastal landscape with a history of extensive forest logging, and a future with projected climate warming that may alter vegetation cover and surface water runoff in new ways. Results from Landsat satellite image time-series analysis since 1983 of this study area showed gradual, statistically significant increases in the normalized difference vegetation index (NDVI) in more than 90 % of the (predominantly second-growth) evergreen forest locations sampled. The cumulative distribution of NDVI values in 2013 was significantly different and higher overall from the cumulative distribution of NDVI values in 1983. The extreme drought year of 2013 (and other previous years of low precipitation) did not affect average NDVI growth rates in most drainage basins of the study area, with the exception of four relatively small basins that had less than 30 % forested land cover. Notably different patterns of NDVI change were detected in areas burned by wildfires in recent years. Within the perimeters of the 2008 Summit Fire and the 2009 Lockheed Fire, NDVI showed notable declines from pre-fire levels to those calculated in 2013 Landsat imagery. In contrast to these recent fires, the burned area from the 1985 Lexington Fire showed the highest rate of NDVI increase (over 27 years of regrowth) of any relatively large contiguous area within the Santa Cruz Mountains.     

Characteristics associated with high and low levels of ecological literacy in a western society

The integrity of the relationship between humanity and nature is fundamental to the health and survival of our species. Humans have always required knowledge and understanding of the planet’s life-supporting systems. Such knowledge and understanding form the basis of ecological literacy which, we suggest, is fundamental to the sustainability of human settlements. An assessment of South Australian adults showed positive correlations between ecological literacy and a number of socio-demographic and psychographic factors. An analysis of the most and least eco-literate individuals within a sample of over 1000 adults revealed significant distinguishing characteristics. Our findings indicate that high ecological literacy is strongly correlated with gender, age, education (and in particular, science-based education), employment status, engagement with nature both as children and adults, growing food, outdoor experiences and lifestyles, growing up in small communities and relational learning. In contrast, low ecological literacy is associated with a different set of socio-demographic and psychographic characteristics such as lower levels of education, growing up in large urban communities, and spending little time outdoors or in natural settings. In addition, perceptions about the major contributors to ecological knowledge and understanding were markedly different within the two groups. These patterns of difference between those with high and low ecological literacy among South Australian adults invite serious consideration for a society that aspires to cultivate an informed citizenry with capacity for making effective environmental decisions.     

ENVIRONMENTAL IMPACT MITIGATION UNDER THE CLEAN WATER ACT AND THE NATIONAL ENVIRONMENTAL POLICY ACT: THE CASE OF TWO FORKS DAM1

ABSTRACT: The role of environmental mitigation in permitting decisions under Section 404 of the Clean Water Act and the National Environmental Policy Act is examined, addressing the extent to which compensatory mitigation is acceptable. The role of mitigation is examined both generically and specifically: first in the requirements of the Clean Water Act and NEPA, and then in the case study of the proposed Two Forks Dam. In both cases, the paper describes dual purposes of environmental protection legislation and mitigation: to protect the biophysical environment and maintain associated human values. Mitigation is found to be sometimes necessary and acceptable as compensation for unavoidable impacts of project development. However, the Two Forks case exemplifies that compensatory mitigation has also been employed as a mechanism to facilitate project development when practicable alternatives entailing less environmental impact are available. Acceptance of compensatory mitigation in such cases violates both the Guidelines of the Clean Water Act and the intent of that Act and NEPA to protect the biophysical environment and human welfare. A recent memorandum of agreement between the Corps and the EPA clarifies this policy, and suggests that permit applications which rely on compensatory mitigation when impacts are available may be denied.     

Cumulative Impacts of Dock Shading on <Emphasis Type="Italic">Spartina alterniflora</Emphasis> in South Carolina Estuaries

Salt marshes dominated by Spartina alterniflora and the associated networks of tidal creeks that drain them are characteristic geographical features of southeastern estuaries, important nursery habitat areas, and preferred sites for residential development. As the size of the coastal population increases, so has the number of requests for dock permits. With each new request for a dock permit, public concerns about the cumulative environmental impacts of dock proliferation on the coastal environment have increased. The objective of this particular study was to evaluate the impacts of shading by dock structures on stem densities of S. alterniflora in South Carolina coastal marshes. Shading impacts under individual docks were extrapolated to the tidal creek (local), county, and statewide scales. Dock structures were sampled both under and next to the walkway in the Charleston Harbor area of South Carolina. The density of S. alterniflora under docks was significantly lower than that which occurred next to the docks (i.e., 5 m away) for the short-form, tall-form, and both forms combined. We estimated that shading effects from dock structures in South Carolina decreased the stem density of S. alterniflora by 71%. Dock shading effects were small when evaluated from the perspective of the amount of marsh that occurs within specific tidal creeks (0.03–0.72%), in coastal counties at a maximum dock length (0.01–0.98%), or statewide (0.01–0.13%) at a maximum dock length. However, approximately 7,000 docks have been permitted over the last decade, resulting in a loss of salt marsh equivalent to 60 ha.1Denise M. Sangers present address: Office of Ocean and Coastal Resource Management, South Carolina Department of Health and Environmental Control, 1362 McMillan Avenue, Suite 400 Charleston, South Carolina 29405, USA. 2 A. Frederick Hollands present address: Hollings Marine Laboratory, National Oceanic and Atmospheric Administration, 331 Fort Johnson Road, Charleston, South Carolina 29412, USA.     

The response of two arctic tundra plant communities to human trampling disturbance

A 4-year study was conducted to evaluate the consequences of human trampling on dryas and tussock tundra plant communities. Treatments of 25, 75, 200 and 500 trampling passes were applied in 0.75 m2 vegetation plots at a time of approximately peak seasonal biomass. Immediately after and 1 and 4 years after trampling, plots were evaluated on the basis of plant species cover, percent bare ground, vegetation height, and soil penetration resistance. One year after trampling, soils were collected for nitrogen analysis in highly disturbed and control plots. Immediately after trampling, 500 trampling passes resulted in approximately 50% cover loss in the dryas tundra and 70% cover loss in tussock tundra, but both communities showed a substantial capacity for regrowth. Plots where low and moderate levels of trampling were applied returned to pre-disturbance conditions by 4 years after trampling, but impact was still evident in plots subjected to high levels of disturbance. These results suggest that these tundra communities can tolerate moderate levels of hiking and camping provided that use is maintained below disturbance thresholds and that visitors employ appropriate minimum-impact techniques. By utilizing this information in a visitor education program combined with impact monitoring and management, it is possible to allow dispersed camping and still maintain these vegetation communities with a minimum of observable impact.     

Ammonia,methane, and nitrous oxide emission from pig slurry applied to a pasture in New Zealand

Much animal manure is being applied to small land areas close to animal confinements, resulting in environmental degradation. This paper reports a study on the emissions of ammonia (NH3), methane (CH4), and nitrous oxide (N2O) from a pasture during a 90-d period after pig slurry application (60 m3 ha-1) to the soil surface. The pig slurry contained 6.1 kg total N m-3, 4.2 kg of total ammoniacal nitrogen (TAN = NH3 + NH4) m-3, and 22.1 kg C m-3, and had a pH of 8.14. Ammonia was lost at a fast rate immediately after slurry application (4.7 kg N ha-1 h-1), when the pH and TAN concentration of the surface soil were high, but the loss rate declined quickly thereafter. Total NH3 losses from the treated pasture were 57 kg N ha-1 (22.5% of the TAN applied). Methane emission was highest (39.6 g C ha-1 h-1) immediately after application, as dissolved CH4 was released from the slurry. Emissions then continued at a low rate for approximately 7 d, presumably due to metabolism of volatile fatty acids in the anaerobic slurry-treated soil. The net CH4 emission was 1052 g C ha-1 (0.08% of the carbon applied). Nitrous oxide emission was low for the first 14 d after slurry application, then showed emission peaks of 7.5 g N ha-1 h-1 on Day 25 and 15.8 g N ha-1 h-1 on Day 67, and decline depending on rainfall and nitrate (NO3) concentrations. Emission finally reached background levels after approximately 90 d. Nitrous oxide emission was 7.6 kg N ha-1 (2.1% of the N applied). It is apparent that of the two major greenhouse gases measured in this study, N2O is by far the more important tropospheric pollutant.     

Risk Management of Sediment Stress: A Framework for Sediment Risk Management Research

Research related to the ecological risk management of sediment stress in watersheds is placed under a common conceptual framework in order to help promote the timely advance of decision support methods for aquatic resource managers and watershed-level planning. The proposed risk management research program relies heavily on model development and verification, and should be applied under an adaptive management approach. The framework is centered on using best management practices (BMPs), including eco-restoration. It is designed to encourage the development of numerical representations of the performance of these management options, the integration of this information into sediment transport simulation models that account for uncertainty in both input and output, and would use strategic environmental monitoring to guide sediment-related risk management decisions for mixed land use watersheds. The goal of this project was to provide a sound scientific framework based on recent state of the practice in sediment-related risk assessment and management for research and regulatory activities. As a result, shortcomings in the extant data and measurement and modeling tools were identified that can help determine future research direction. The compilation of information is beneficial to the coordination of related work being conducted within and across entities responsible for managing watershed-scale risks to aquatic ecosystems.