Soil‐plant Diversity Relationships on a Disturbed Site in Northwestern Colorado

Abstract

A 5‐yr‐old revegetation plot in the Piceance Basin of northwestern Colorado was used to study the relationship between several soil properties and plant species diversity. Soil properties, including coarse fragment content, topography, depth to bedrock, rooting depth, soil volume, fertility, and salt content, were quantified for 108 subplots. Using simple and multiple regression techniques, plant diversity on the subplots was correlated with the various soil properties. A seed mixture composed of introduced grasses and forbs was used most extensively to study diversity‐soil physical property relationships. For these plots, percent large coarse fragments (> 4.76 mm) within the rooting depth had a high positive correlation with the Shannon‐Weiner diversity index. Depth to bedrock, rooting depth, total soil volume, soil volume within the rooting depth, and a topographic index all exhibited negative correlations with the Shannon‐Weiner index. On plots seeded with a native grass‐forb seed mixture, where variation in salt content was greatest, SAR, ESP, and EC had positive correlations with species richness. When all seed mixtures were considered, rate of fertilizer application had a negative correlation with the Shannon‐Weiner index. In every case where a regression was significant, soil properties normally associated with high production resulted in low diversity and soil properties normally associated with low production resulted in high diversity. Mechanisms are proposed to explain the relationships between soil factors and diversity. Management techniques are also suggested which could be incorporated into the reclamation process to increase plant diversity.

Plant community dynamics in a semi-arid ecosystem in relation to nutrient addition following a major disturbance

“…The climate is semi-arid, characterized by a relatively dry period from mid-May through mid-September (Stark, 1983). The study plots are located on Yamac loams (fine-loamy mixed, Borollic Camborthids) which normally support a big sagebrush (Artemisia tridentata) steppe vegetation type.…”

“…Tilman (1984) showed that nutrient additions to a lowfertility Minnesota sand plain caused plant species composition to differ from unfertilized controls. In a semi-arid ecosystem, Stark and Redente (1985) and Biondini and Redente (1986) found that large single applications of mineral nitrogen and phosphorus reduced plant species diversity five years after disturbance. The overall objective of this research was to determine if effects of increased availability of mineral nutrients observed in more mesic systems would occur in a semi-arid, shrub-dominated system where plant growth is largely limited by water availability.…”

Long‐Term Plant Community Development on Topsoil Treatments Overlying a Phytotoxic Growth Medium

“…The reclamation of mined lands in the western USA must achieve specific goals in terms of total production and plant species diversity; however, research has shown that productive, yet diverse plant communities are difficult to re·create (DePuit, 1984;Stark and Redente, 1985;Biondini and Redente, 1986). Some authors have successfully obtained both by increasing the number of species in an all-native seed mixture (DePuit and Coenenberg, 1979), or by using irrigation to manipulate composition of the seeded community (Redente and DePuit, 1988).…”

“…Some authors have successfully obtained both by increasing the number of species in an all-native seed mixture (DePuit and Coenenberg, 1979), or by using irrigation to manipulate composition of the seeded community (Redente and DePuit, 1988). Other authors (DePuit, 1984;Stark and Redente, 1985) have suggested the application of various depths of topsoil across the landscape as a potential strategy for obtaining productive and diverse plant communities. The results of the current study indicate that productive and relatively species-rich native plant communities can be established and maintained over phytotoxic mine waste materials with the use of at least 30 em of topsoil, a diverse seed mixture of native species, and no initial fertilization.…”

Effects of soil and wood depletion on biodiversity

“…If several resources are depleted simultaneously, biodiversity losses could also be significantly greater because of synergistic effects. Plant communities, for instance, are likely to experience large changes in species composition if both soil and water resources are depleted concurrently, because soil conditions and water availability are key determinants of the performance of individual plant taxa (Stark and Redente, 1985;Crawley, 1986). Finally, resource depletion could interact with other stresses, such as acid rain, ozone depletion, pollution or climate change, to accelerate biodiversity losses.…”