2013-07-11_REPORT - M1988044 (2)

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military bases where a lot of field exercises occur. The persistent disturbance simply makes land highly vulnerable to these opportunistic "devil" plants and these plants are very good at capitalizing on opportunity. Individual Reclamation Areas: This new section which was added last year will not be used this year. As there are no new reclamation areas and the older ones were released upon approval by DRMS, this section will return to use in future annual reports as new reclamation is implemented. F. Description of animal impacts on revegetation: No significant animal impacts were noted. Pronghorn do graze the older revegetation, but the pronghorn population is small relative to the amount of land that produces food for them. Therefore, any impacts are negligible. Rodents, mainly prairie dogs, are not a problem in any of the revegetation areas. Prairie dog impacts on this land tend to be a mixture of both good and bad effects. First, prairie dogs, as is well known, tend to till the soil bringing nutrients locked deep in the soil to the surface and also improving water infiltration. Second, the prairie dog towns on this site, in recent years, have generally devastated the natural vegetation and often have inflicted more damage than was seen by overgrazing. One new prairie dog town adjacent to some old reclamation work exhibits very sparse growth and severely cropped grasses while, at the same time, the reclaimed mined land is in excellent condition with tall, dense grasses and forbs. In fact, it is so bad one person on a recent inspection thought the prairie dog town was the land that had been mined. That is not the case and, in fact, prairie dogs generally do not invade reclaimed land. It is not known why that is the case, but it probably has to do with the suitability of the reclaimed soil to be used for building burrows. The reclaimed soils are comparatively new and therefore lack the density and structural variations of natural soils and likely do not hold up when tunneled. This lower density may be a factor in determining the exact plant species composition on reclaimed soil as compared to unmined soil. As the plant species, irrespective of the numerical relationships, are certainly edible for prairie dogs, unsuitable vegetation composition can be ruled out as the factor limiting prairie dog invasion of reclaimed land. The plant species on reclaimed and unmined land may be the same, but the numerical structure of the vegetation components are almost always different until soil sorting processes can create the fine structure of the natural soils. So, even though the vegetation is attractive to prairie dogs, they avoid it because they do not want to be that far from home to find food for fear they would become food. A major soil development process that creates that structure is called illuviation. Illuviation is a process that carries fine particles deeper into the soil to produce higher density soils below the surface. This becomes a major factor in constructing mature soil profiles and different horizons in the soil. As this process only occurs to any significant degree when precipitation exceeds evaporation, the creation of dense deep soils capable of maintaining a prairie dog burrow without collapsing takes a very long time. If drought is the rule, as has been the case in the last decade, illuvial sorting is simply not occurring to any extent except in locations where runoff accumulates and Status report for 2013 due July 15, 2013 Page 9 of 16