DOI: 10.5061/dryad.s1f95
title: Data from: Designed habitat heterogeneity on green roofs increases seedling survival but not plant species diversity

description: Urban areas benefit from the ecosystem services provided by low input
 green roofs. However, limited substrate depth on these green roofs creates
 challenging conditions for plant establishment and survival, leading to
 industry reliance on non-native succulents. Through a green roof and
 glasshouse study, we assessed the impact of simple design modifications to
 the green roof surface, including redistribution of substrate and addition
 of logs and pebble piles, on both substrate temperature and moisture
 content. We added seeds of 26 native species and quantified seedling
 density, species richness and composition over a single growing season.
 Overall effects of microsite heterogeneity on species diversity were
 assessed using species accumulation curves. The modifications altered
 substrate temperature and moisture. Deep substrate (10-12 cm) and the
 presence of surface features reduced temperature by 14.6°C and, while
 surface features had mixed effects on substrate moisture on the green
 roof, pebble piles slowed moisture loss during a six-week drought in the
 glasshouse. Following drought conditions, seedling density and species
 richness was greatest, relative to seeded controls, where substrate was
 deep on the green roof and where pebbles were present in glasshouse
 modules, despite high mortality overall. Design modifications did not
 result in differentiation of seedling communities among different
 microsite types. Species accumulation curves showed no difference in
 species richness between aggregates of modified vs. unaltered microsites.
 Synthesis and applications. Redistribution of green roof substrate and the
 addition of logs and pebble piles altered microsite conditions and created
 habitat heterogeneity on a green roof. These design modifications
 represent a minimalist strategy to ameliorate growing conditions, improve
 seedling survival and decrease species loss on shallow substrate green
 roofs.
description: Atrium green roof
 temperature, moisture, seedling density, and species richness 2014
 dataData pertaining to
 Tables 2 & 3 and Figure 4. Includes data from the Atrium green roof
 collected in June and September of 2014. Data measured per quadrat
 (100cm2), with experimental quadrats assigned to 12 distinct microsite
 types relating to substrate depth (shallow, control, deep) and substrate
 features (none, logs, pebble pile center, pebble pile edge); abiotic data:
 substrate temperature (degrees Celsius), substrate volumetric water
 content (VWC, %), biotic data: seedling density (number of
 seedlings/100cm2), and species richness (species/100cm2). Covariate data
 (% cover of vegetation, total solar radiation) are also included
 here.Atrium
 green roof temperature, moisture, seedling density, and species richness
 2014.txtAtrium green roof
 species richness data 2014 - EstimateS outputSpecies richness output
 from EstimateS - used to create Figure 5. Microsites categorized as seeded
 controls (homogeneous conditions) or heterogeneous (mixed microsites).
 Combined homogeneous area sampled = 2400 cm2, combined heterogeneous area
 sampled = 9600 cm2.glasshouse module
 temperature, moisture, seedling density, species richness
 2015Data from glasshouse
 modules, used to create Figure 6. Contains data according to treatment
 (surface feature type) and time, including substrate temperature (degrees
 Celsius), volumetric moisture content (VWC, %), seedling density
 (seedlings/1296 cm2), and species richness (per 1296
 cm2).