2.4 Introduction of toxic chemicals into the site's soils 



2.5 Displacement of sensitive wildlife species from adjacent areas 

 due to treatment processes and periodic human activity 



Attribute alterations 



Conversion of a well to production status creates few additional 

 site alterations. All activities occur around the wellhead and 

 central pad area. Operation consists of periodic maintenance and 

 inspection visits. Equipment repair may occasionally require 

 limited activity on the pad. Outlying portions of the pad revege- 

 tate following reduced disturbance levels. Consequently, considera- 

 tions of the primary ecological alterations are concerned primarily 

 with the construction and operation of a central treatment complex 

 and pipeline pumping station. 



Attribute alterations are similar in scope but smaller in scale than 

 for wellsite preparation. Site preparation for the treating complex 

 and pumping station removes all biotic components within the con- 

 struction boundaries through cutting and clearing, grading, filling, 

 and excavation activities. Similar effects are produced in all 

 three community types. A direct loss of approximately 0.4 ha (1 acre) 

 of sustaining habitat results for primary and secondary consumers. 

 Food and cover elimination is particularly significant for small 

 mammals, nesting songbirds, and soil invertebrates as proportionally 

 larger portions of their resource bases are altered. Secondary 

 consumers are affected indirectly by the removal or reduction of 

 herbivorous prey organisms as well as loss of cover. Nesting, 

 foraging, escape, and resting areas are altered or destroyed. Avian 

 and mammalian species vary widely in their tolerance to habitat 

 disturbance. Some species tolerate little alteration, while others 

 are found only in severely disturbed situations. In each case, 

 species response is a function of time elapsed and the creation or 

 destruction of the required niche. Impact magnitude is a function 

 of the species' resource base and the importance of the removed 

 vegetation. 



Removal of plant cover encourages surface-water runoff from barren, 

 newly exposed sediments into adjacent upland systems. The resultant 

 effects, as partially regulated by slope and elevation, are usually 

 restricted in areal extent. Interruption of detrital and nutrient 

 cycles, with subsequent nutrient reserve depletion through runoff 

 and leaching, inhibit rapid plant recovery following site abandon- 

 ment and restoration attempts. 



Soil structure within the construction easement is decreased by the 

 compaction due to vehicular traffic and concrete foundations and 



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