Plant and Soil Responses to Created Microtopography and Soil Treatments in Bottomland Hardwood Forest Restoration

Abstract

Although microtopographic heterogeneity is common in bottomland hardwood forests, it is rarely considered in bottomland restoration efforts. The objective of this study was to determine the responses of hydrologic condition, soil physiochemical properties, and introduced and colonizing vegetation to created microtopography and soil treatments at a landfill borrow pit in northern Texas. A series of mounds and pools were created and planted with fast-growing pioneer species as well as more desirable, later-successional species. Erosion control mats were installed on half the plots as a source of organic matter. Erosion control mats had little influence on introduced seedling survival or colonizing species abundance, but microtopography strongly influenced hydrologic condition, soil properties, seedling survival and growth, and colonizing species abundance and distribution. Pools were flooded during much of the summer months and had significantly higher nitrate and total nitrogen concentrations than mounds. Topographic position had little effect on survival of pioneer species, but mortality of most latersuccessional species was highest in pools. Colonizing species distribution and abundance were also strongly related to topographic position. Despite differences in soil nutrient concentration among topographic zones, hydrologic condition likely had the strongest influence on growth and survival of planted species and distribution of colonizing species. Creating microtopography resulted in a spatially heterogeneous system that reflected variations in natural bottomlands, and introducing a mix of species (pioneer and later-successional) across topographic and hydrologic gradients may improve the establishment and survival of a diverse community when hydrologic condition is highly variable or difficult to predict.

Artificial microtopography and herbivory protection facilitates wetland tree (Thuja occidentalis L.) survival and growth in created wetlands

“…However, this limits the site to a single water table depth, which can limit species diversity and create a greater risk of mortality of planted seedlings from seasonal high water. Research of Bruland and Richardson (2005) and Simmons et al (2011) have highlighted the importance of topographic heterogeneity in restored bottomland hardwood forests in the southern United States. Our results suggest that the same may be true for northern white-cedar wetlands.…”

“…For this reason, elevated microtopography could be an important component in natural regeneration of northern white-cedar in wetlands, especially during the critical stages of germination and seedling establishment. Previous studies investigating the effects of artificially-created microtopography on tree growth and survival have primarily taken place in bottomland hardwood swamps, which have shown that the drier conditions of hummock tops and ridges increase performance and survival of certain tree species (Simmons et al 2011(Simmons et al , 2012. Studies involving microtopography in northern whitecedar wetlands have been of natural systems, where microtopography is primarily composed of organic material (Chimner and Hart 1996).…”

“…The success of some species can be facilitated by mimicking the topographic heterogeneity of natural wetlands (Stanturf et al 2001); thus, artificially-created microtopography has become an important tool in wetland creation and restoration in recent years (Barry et al 1996;Bruland and Richardson 2005;Ahn and Dee 2011;Simmons et al 2011). Microtopography, defined as small-scale topographic variation at the scale of up to 1 m (Moser et al 2007), is a common feature of many types of natural wetlands.…”

“…Simmons et al 2011, Results of the mixed model ANOVA and Tukey-Kramer post hoc tests for northern white-cedar survival in Petoskey (a) and Isabella (b) by microtopography and fencing. Bars on columns represent SE, letters represent significant differences at p \ 0.05.…”

A Biogeochemical Examination of Ontario’s Boreal Forest Ecosite Classification System

“…However, given the practical limitations related to sampling strategies in both the ecosite classification process and this study, it is difficult to characterize fine scale variability. For example, Simmons et al [33] found in a study of bottomland forests that microtopography at scales of decimeters or less affected hydrologic conditions, nutrient concentrations, and species composition. Microbial communities, another important control on many soil processes, also vary substantially at fine scales; Snajdr et al [34] assessed the spatial variability of enzyme activities and microbial biomass in upland hardwood forest soils and found significant differences between samples taken only 1 cm apart.…”