Engineering novel habitats on urban infrastructure to increase intertidal biodiversity

Abstract

Urbanization replaces natural shorelines with built infrastructure, seriously impacting species living on these "new" shores. Understanding the ecology of developed shorelines and reducing the consequences of urban development to fauna and flora cannot advance by simply documenting changes to diversity. It needs a robust experimental programme to develop ways in which biodiversity can be sustained in urbanized environments. There have, however, been few such experiments despite wholesale changes to shorelines in urbanized areas. Seawalls--the most extensive artificial infrastructure--are generally featureless, vertical habitats that support reduced levels of local biodiversity. Here, a mimic of an important habitat on natural rocky shores (rock-pools) was experimentally added to a seawall and its impact on diversity assessed. The mimics created shaded vertical substratum and pools that retained water during low tide. These novel habitats increased diversity of foliose algae and sessile and mobile animals, especially higher on the shore. Many species that are generally confined to lowshore levels, expanded their distribution over a greater tidal range. In fact, there were more species in the constructed pools than in natural pools of similar size on nearby shores. There was less effect on the abundances of mobile animals, which may be due to the limited time available for recruitment, or because these structures did not provide appropriate habitat. With increasing anthropogenic intrusion into natural areas and concomitant loss of species, it is essential to learn how to build urban infrastructure that can maintain or enhance biodiversity while meeting societal and engineering criteria. Success requires melding engineering skills and ecological understanding. This paper demonstrates one cost-effective way of addressing this important issue for urban infrastructure affecting nearshore habitats.

Differential patterns of distribution of limpets on intertidal seawalls: experimental investigation of the roles of recruitment, survival and competition

“…Thus, the material used to build artificial structures may influence rates of recruitment, the amounts and types of food resources, or the quality of habitat due to the lack of many macro-habitats , Chapman & Blockley 2009). Here, 2 species of limpets that have complex competitive interactions with numerous other species on natural shores showed similar complex interactions on plates attached to vertical seawalls, which varied according to the material of the plate.…”

Cool barnacles: Do common biogenic structures enhance or retard rates of deterioration of intertidal rocks and concrete?

“…At the same time, a recognition that artificial structures are often poor ecological surrogates for the natural rocky shores they may replace (e.g., Bulleri and Chapman, 2004;Gacia et al, 2007;Firth et al 2013;Firth et al 2016) is fuelling considerable international effort to develop and test ways of encouraging their colonisation. This includes structural design interventions and retrofit solutions aimed at facilitating settlement and recruitment of benthic species, to support biodiversity and maintain ecological function (e.g., Chapman and Blockley, 2009;Evans et al, 2015;Firth et al, 2014, Firth et al 2016Sella and Perkol-Finkel, 2015).…”

Ecology of freshwater shore zones

“…As the ecological services provided by shore zones have received greater visibility, it has been natural to ask whether shore zones could be engineered to increase the ecological services that they provide while at the same time satisfying human needs for flood control, etc. The ecological engineering of shore zones is still a young field, and has been focused mainly on marine shores (e.g., Airoldi et al 2005;Martin et al 2005;National Research Council 2007;Chapman and Blockley 2009). Marine ecologists have made suggestions about which design features of engineered structures will affect their ecological value (Table 1), as well as principles that might be used to manage shore zones taking ecological services into account (Table 2).…”