Baltimore Ecosystem Study Institute of Ecosystem Studies

2011 BES Annual Meeting Presentation and Poster Abstracts

Does habitat management explain multi-scale biodiversity patterns in built ecosystems?
Suski, Jamie
Co-Authors: Salice, C.J and Swan, C.M.

Urban environments continue to expand, and exhibit shifts in environmental characteristics that can provide novel habitat at different spatial scales. Stormwater ponds are common in urban landscapes, and serve as functional habitat for many organisms. Humans often manage these ponds for aesthetic reasons, but the implications of such management for biodiversity unknown. Aquashade is a blue dye that absorbs sunlight within the water column to inhibit primary production and is added to many ponds to improve clarity. Ponds also receive nutrients from fertilized yards, parks and waterfowl feces. We were interested in the zooplankton community dynamics of managed ponds, where nutrient loading is likely occurring and primary productivity is limited due to Aquashade application. We hypothesized that: (1) Aquashade acts as an environmental filter that constrains zooplankton community composition by altering their food base, (2) nutrients increase primary production in the absence of Aquashade, altering composition of zooplankton, and (3) dispersal increases local zooplankton diversity, but decreases compositional turnover among ponds. To address our hypotheses we conducted a full-factorial experiment using 600-L mesocosms with two Aquashade treatments (present, absent), two nutrient treatments, (supplemented, unsupplemented) and two dispersal treatments (dispersal, no- dispersal). Our results suggest Aquashade and nutrients increase local diversity, but decreases compositional shifts of zooplankton communities between ponds. Our results support that management of algae significantly constrains assemblage structure in space. Active management of these ponds may enhance local diversity, but reduce compositional turnover among ponds, suggesting a mechanism by which diversity is maintained in built ecosystems.