Context-dependent success of restoration of a key species, biodiversity and community composition

Abstract

Increasingly, restoration is seen as a management and conservation tool, with aims of restoring not just a single species but a natural functioning community. In marine soft sediment systems, biodiversity and communities are often strongly related to the presence of key species, suggesting that restoration of a single species could result in restoration of communities/biodiversity. The success of such a restoration is likely to be context-dependent, driven by hydrodynamics, local diversity and ambient communities. A transplant experiment with adult Austrovenus stutchburyi was conducted in 2 different hydrodynamic compartments of a large New Zealand harbour. After 1 yr, densities of transplant sized individuals and smaller adults were enhanced at both sites, although enhancement of juveniles only occurred at 1 site. Measures of diversity did not increase in the experimental plots; however, at 1 site the benthic macrofaunal community had changed. Probable reasons for the location-dependent results are differences in hydrodynamic connectivity and ambient communities, although density-dependent effects driven by small differences in the success of adult enhancement may also have been important.

The bivalve loop: Intra-specific facilitation in burrowing cockles through habitat modification

“…Thrush et al, 1996Thrush et al, , 2000Wright et al, 2006). However, the lower experimental densities and smaller spatial scales considered in previous studies, as well as landscape factors such as site connectivity and habitat fragmentation, could also be the cause (Hewitt and Cummings, 2013;Hewitt et al, 1997), as both the densities and the spatial and temporal extent of ecosystem engineers affect the magnitude of habitat modification (Cuddington et al, 2009;Jones et al, 1997), and the patchiness of bivalve populations may influence local availability of recruits. In our study, thirty-two 25 m −2 cockle-dominated communities were created and monitored over one year, offering an unprecedented opportunity to investigate engineering effects of adult cockles on recruitment success of juveniles, defined here as the result of settlement and survival of 3 to 6 month individuals.…”

Multiple stressors, nonlinear effects and the implications of climate change impacts on marine coastal ecosystems

“…Adult Macomona control macrofaunal community composition, pore water pressure gradients, the presence of anoxic water at the sediment – water interface and nutrient fluxes (Thrush et al ., , , ; Volkenborn et al ., ). Austrovenus , while a lesser driver of macrofaunal community composition, does control primary productivity, nutrient fluxes and sedimentation rates (Thrush et al ., , ; Sandwell et al ., ; Hewitt & Cummings, ). A positive feedback loop has been demonstrated to exist between mud content, sediment chlorophyll a and Austrovenus density in clear water that is broken when light levels are decreased (Thrush et al ., ).…”

Seagrass Restoration Is Possible: Insights and Lessons From Australia and New Zealand

“…Heavier emphasis is given to Australian restoration work in this review, largely due to the fact that although there has been recent activity with regards to seagrass restoration in New Zealand, the New Zealand effort to date, lags far behind Australia and the world. With the exception of the research undertaken by Matheson, restoration efforts in New Zealand are typically focused upon shellfish (e.g., Marsden and Adkins, 2010;Hewitt and Cummings, 2013), which are important taonga for Māori (e.g., Paul-Burke et al, 2018). Seagrass research in New Zealand has focused on understanding fundamental community ecology and biology (e.g., Dos Santos et al, 2012;Kohlmeier et al, 2014;Morrison et al, 2014;Sørensen et al, 2018;Cussioli et al, 2019Cussioli et al, , 2020, macroinvertebrate and fish communities interactions (e.g., Mills and Berkenbusch, 2009;Lundquist et al, 2018) and impacts upon these communities (e.g., Bulmer et al, 2016;Cussioli et al, 2019;Li et al, 2019;Matheson et al, submitted).…”