The ecology of restoration: historical links, emerging issues and unexplored realms

Abstract

Restoration ecology is a young academic field, but one with enough history to judge it against past and current expectations of the science's potential. The practice of ecological restoration has been identified as providing ideal experimental settings for tests of ecological theory; restoration was to be the Ôacid testÕ of our ecological understanding. Over the past decade, restoration science has gained a strong academic foothold, addressing problems faced by restoration practitioners, bringing new focus to existing ecological theory and fostering a handful of novel ecological ideas. In particular, recent advances in plant community ecology have been strongly linked with issues in ecological restoration. Evolving models of succession, assembly and state-transition are at the heart of both community ecology and ecological restoration. Recent research on seed and recruitment limitation, soil processes, and diversity-function relationships also share strong links to restoration. Further opportunities may lie ahead in the ecology of plant ontogeny, and on the effects of contingency, such as year effects and priority effects. Ecology may inform current restoration practice, but there is considerable room for greater integration between academic scientists and restoration practitioners. Ecological restoration is Ôintentional activity that initiates or accelerates the recovery of an ecosystem with respect to its health, integrity and sustainabilityÕ SER (2004). Restoration ecology is the field of science associated with ecological restoration. The practice of ecological restoration is many decades old, at least in its more applied forms, such as erosion control, reforestation, and habitat and range improvement. However, it has only been in the last 15 years that the science of restoration ecology has become a strong academic field attracting basic research and being published in indexed peer-reviewed journals (Fig. 1). Associated with this growth has been an increasing desire to define a scientific identity for restoration ecology and its relationship to ecological restoration.Early on, far-sighted ecologists recognized that the practice of ecological restoration could be an Ôacid testÕ of ecological theory (Bradshaw 1987), and conversely, recognized that the highly manipulative nature of ecological restoration provided an ideal setting for hypothesis generation and testing in ecology (Jordan et al. 1987b). One of the first attempts to delineate an ecological discipline centred on restoration was the seminal volume by Jordan et al. (1987a). In recent years, there has been considerable discussion of the conceptual bases of restoration ecology (Cairns & Heckman 1996;Hobbs & Norton 1996;Allen et al. 1997;Perrow & Davy 2002;Peterson & Lipcius 2003;Temperton et al. 2004; van Andel & Grootjans 2005;Aronson & van Andel 2005). There emerge two kinds of questions about the links between conceptual ecology and ecological restoration. First, what set of ecological principles and concepts serve as an essential basis for ...

Cluster planting facilitates survival but not growth in early development of restored tropical forest

“…Understanding structuring forces in tropical plant communities is important to develop efficient restoration model based on scientific results, since theoretical basis of restoration ecology derives from basic concepts of community ecology (Young et al 2005). Evaluating performance of tropical trees requires a longer time to observe consistent patterns, and results presented here may show just the first step of the undergoing processes.…”

“…Following the framework presented above, we predicted that (1) fast growing plants (pioneers) would provide shade for slow growing species (non-pioneers) and facilitate their survival and growth in degraded areas (Yang, Ren, Liu, & Wang 2010); thus non-pioneers would respond more positively in the aggregated planting; and (2) pioneers should be in competitive disadvantage for nutrients and hence would benefit more from nutrient enrichment. Such manipulative experiments in restoration projects represent excellent opportunities to test and refine ecological theories, which in turn may contribute to new insights in developing restoration models (Young, Petersen, & Clary 2005). Despite the theory and empirical bases for those predictions, they have never been tested in a multi-species restoration context in the tropics.…”

Plant traits explain the success of vacuum harvesting as a method of seed collection for the restoration of species-rich grasslands

“…Where priority effects linked to the order of species establishment have long-term consequences, such differences may be either hard to overcome using subsequent management, or even permanent (Young et al 2005). For example, the high emergence rates of competitive grass species from the collected material (e.g.…”

“…While these problems have received limited attention in the literature, such sampling bias could potentially affect what species become established during grassland restoration (Stevenson et al 1997;Riley et al 2004;Kiehl et al 2010). The order with which species establish into new grasslands, so called 'priority effects', can have long-term ramifications for the structure of plant communities (Young et al 2005). If suction sampling of seeds preferentially biases certain plant functional types then such priority effects may undermine the validity of vacuum harvesting as a method for promoting grassland restoration (Young et al 2005).…”

“…The order with which species establish into new grasslands, so called 'priority effects', can have long-term ramifications for the structure of plant communities (Young et al 2005). If suction sampling of seeds preferentially biases certain plant functional types then such priority effects may undermine the validity of vacuum harvesting as a method for promoting grassland restoration (Young et al 2005).…”