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Hydrogeomorphic (HGM) functional assessment models were used to assess whether function in created wetlands of two ages (1 year
old and >12 years old) was equivalent to that of natural (reference) mainstem floodplain wetlands. Reference wetlands scored
higher than both created age classes for providing energy dissipation and short-term surface water storage. Reference wetlands scored higher in maintaining native plant community and structure than 1-year-old sites, and 12-year-old wetlands scored higher than reference sites for providing vertebrate habitat structure. Analysis of individual model variables showed that reference wetlands had greater vegetative biomass and higher soil organic
matter content than both created wetland age classes. Created wetlands were farther from natural wetlands and had smaller
mean forest patch sizes within a 1-km-radius circle around the site than did the reference sites, indicating less hydrologic
connectivity. Created wetlands also had less microtopographic variation than reference wetlands. The 1-year-old created sites
were placed in landscape settings with greater land use diversity and road density than reference sites. The 12-year-old sites
had a higher gradient and a higher percentage of their surrounding area in urban land use. These results show that the created
wetlands were significantly structurally different (if not functionally so) from reference wetlands even after 12 years. The
most profound differences were in hydrology and the characteristics of the surrounding landscape. More attention needs to
be focused on placing created wetlands in appropriate settings to encourage proper hydrodynamics, eliminate habitat fragmentation,
and minimize the effects of stressors to the site. 相似文献
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Wild rodents were collected using live snap traps in pistachio gardens of Kerman Province, Southeast Iran from 2007 to 2009, then some physiological parameters of them were measured. The samples were identified as follow: Nesokia indica, Meriones persicus, Meriones lybicus and Tatera indica. Blood samples were obtained from the heart, then the blood parameters (glucose, cholesterol, triglyceride, total protein, HDL, red and white blood cell number) in wild species of rodents and laboratory rat were compared. The results showed that there were no significant differences in serum glucose, triglyceride, HDL and total protein levels among different experimental groups. The concentration of cholesterol in T. indica was more than that in N. indica (P < 0.01). The total numbers of red blood cells also showed significant difference between wild garden rodent species and laboratory rat (P < 0.01), while the numbers of white blood cells showed no significant difference. 相似文献
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In the United States, the Clean Water Act requires mitigation for wetlands that are negatively impacted by dredging and filling
activities. During the mitigation process, there generally is little effort to assess function for mitigation sites and function
is usually inferred based on vegetative cover and acreage. In our study, hydrogeomorphic (HGM) functional assessment models
were used to compare predicted and potential levels of functional capacity in created and natural reference wetlands. HGM
models assess potential function by measurement of a suite of structural variables and these modeled functions can then be
compared to those in natural, reference wetlands. The created wetlands were built in a floodplain setting of a valley in central
Pennsylvania to replace natural ridge-side slope wetlands. Functional assessment models indicated that the created sites differed
significantly from natural wetlands that represented the impacted sites for seven of the ten functions assessed. This was
expected because the created wetlands were located in a different geomorphic setting than the impacted sites, which would
affect the type and degree of functions that occur. However, functional differences were still observed when the created sites
were compared with a second set of reference wetlands that were located in a similar geomorphic setting (floodplain). Most
of the differences observed in both comparisons were related to unnatural hydrologic regimes and to the characteristics of
the surrounding landscape. As a result, the created wetlands are not fulfilling the criteria for successful wetland mitigation. 相似文献
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