The ecological equivalence of quarry floors to alvars

Abstract

Question: Are the biophysical conditions of abandoned limestone quarry floors and natural alvars sufficiently similar to each other for alvars to be used as a model for quarry floor restoration? Location: Ontario, Canada. Methods: We measured plant species frequency and environmental and soil variables in 13 abandoned limestone quarries and used ANOVA to compare them with data previously collected from seven natural alvars. We used multivariate ordinations on the quarry floor data alone and on the combined quarry floor and alvar data to determine how plant community structure was controlled by the abiotic environment in both habitats. Results: Except for higher levels of many nutrients, the physical characteristics were similar between quarry floors and alvars. 246 plant species were found on quarry floors as compared to 283 on alvars, with 79 species in common between the two habitat types. While quarry floors supported fewer bryophytes and more exotic vascular plants compared with alvars, five alvar endemics and 24 characteristic alvar species were found to grow there. The age of the site, nutrient levels, and presence of standing water and bare rock were important factors influencing species composition in both habitats. Conclusions: Through natural revegetation alone, the abandoned quarry floors surveyed in this study have already taken on many physical and vegetation characteristics of natural alvars. This makes alvars very suitable as the restoration goal for abandoned limestone quarries.

Fine‐scale spatial heterogeneity and incoming seed diversity additively determine plant establishment

“…Mean soil depth was approximately 4 cm but highly variable, ranging from 0 cm to more than 30 cm. Quarry substrates were alkaline (mean pH = 7.8), of low to moderate fertility, and contained a mineral fraction of crushed CaCO 3 residual from quarrying (for further details on soil properties, see Tomlinson et al. 2008).…”

MINI‐REVIEW: Habitat analogues for reconciliation ecology in urban and industrial environments

“…However, some types of industrial sites have analogues in natural ecosystems, suggesting that rehabilitation goals can be met even if restoration to a historical state is never achieved, by using ecosystem analogues as reconstruction targets and industrial sites as habitat for conservation‐priority species and community types (Richardson, Lundholm & Larson 2010). As with urban ecosystems, evidence for such analogues comes from industrial sites attracting consistent biota which are locally novel but regionally confined to specific ecosystem types (Tomlinson et al 2008; Tropek et al 2010). To a greater degree than in urban ecosystems, many experiments testing the idea that native species can thrive in post‐industrial ecosystems provided that microhabitat conditions are matched and propagules are made available, have already been performed (Ash, Gemmell & Bradshaw 1994; Herath et al 2009).…”

Can we Create Alvars or Fully Restore those Damaged?

“…(5) Tomlinson et al (2008) This article projects that conditions on the floors of abandoned limestone quarries are similar to those on alvars and some of the species that are found on alvars also occur on abandoned quarry floors. Although observations were not new (see text box), it was of interest because it suggested that alvars could be used as a model, or analogue, for efficiently greening quarries and simultaneously protecting some rare and at-risk alvar species (extended by Richardson et al 2010).…”

“…The work of Tomlinson et al (2008) was not designed to compare alvar and quarry floor vegetation; otherwise it would have used information such as cover, fruiting condition, number of individuals and biodiversity measures instead of just presence or absence. Nevertheless, the paper does indicate that alvars are biologically quite different from quarry floors: (1) Figure 1a shows all the alvar samples on the left side with almost no overlap between these and quarry samples; (2) In Figure 2c there are two major groups of species, the one with few exotics evidently represents the alvars.…”