Wetland management strategies lead to tradeoffs in ecological structure and function

Abstract

Anthropogenic legacy effects often occur as a consequence of land use change or land management and can leave behind long-lasting changes to ecosystem structure and function. This legacy is described as a memory in the form of ecological structure or ecological interactions that remains at a location from a previous condition. We examined how forested floodplain restoration strategy , based on planting intensity , influenced wetland community structure and soil chemical and physical factors after 15 years. The site was divided into 15 strips , and strips were assigned to one of five restoration treatments: plantings of acorns , 2-year-old seedlings , 5-ft bareroot trees , balled and burlapped trees , and natural seed bank regeneration. Our community composition survey revealed that plots planted with bareroot or balled and burlapped trees developed closed tree canopies with little herbaceous understory , while acorn plantings and natural colonization plots developed into dense stands of the invasive species reed canary grass (RCG; Phalaris arundinacea). Restoration strategy influenced bacterial community composition but to a lesser degree compared to the plant community response , and riverine hydrology and restoration strategy influenced wetland soil conditions. Soil ammonium concentrations and pH were similar across all wetland restoration treatments , while total organic carbon was highest in forest and RCG-dominated plots compared to mixed patches of trees and open areas. The differences in restoration strategy and associated economic investment resulted in ecological tradeoffs. The upfront investment in larger , more mature trees (i.e. , bareroot , balled and burlapped) led to floodplain forested communities , while cheaper , more passive planting strategies (i.e. , seedlings , seedbank , or acorns) resulted in dense stands of invasive RCG , despite the similar floodplain hydrology across all sites. Therefore , recovery of multiple ecosystem services that encompass plant and microbial-derived functions will need to include additional strategies for the recovery of plants , microbes , environment , and functions