Martha D. Graf

Spontaneous revegetation of cutwaway peatlands of North America

Modern extraction methods permit peat to be extracted to the minerotrophic layer of ombrotrophic peatlands (bogs). As the environmental conditions of these harvested peatlands are similar to minerotrophic peatlands (fens), such sites should be restored towards a fen system. However, it is not known whether fen species would recolonize such harvested sites on their own. We surveyed vegetation and environmental variables in 28 harvested peatlands with minerotrophic residual peat across Canada and in Minnesota, USA, and compared them to 11 undisturbed fens. Compared to harvested bogs previously studied, the harvested fens sampled in this study revegetated remarkably quickly (50%–70% vegetation cover) when the hydrological conditions were suitable. However, revegetation was less extensive for sites that were still drained (25% vegetation cover). A high water table and a thin layer of residual peat were the most important factors contributing to rapid recolonization rates. Although the harvested fens were rapidly recolonized, species composition was not the same as observed on undisturbed fens. Carex and Sphagnum, dominant in undisturbed fens, generally did not recolonize harvested fens. Thus, whether the goal is to increase species richness or to ensure the return of peat accumulating functions, fen species may have to be actively introduced.

How Fen Vegetation Structure Affects the Transport of Oil Sands Process-affected Waters

Oil sands mining in the Athabasca oil sands region disturbs large tracts of peatlands as the vegetation-soil layer must be removed. Processing oil sands produces large volumes of wet material containing oil sand process-affected water (OSPW) that has elevated concentrations of sodium (Na) and naphthenic acids (NAs). Attempts to reclaim mined landscapes to peat-forming systems command knowledge of the transport, fate and impact of OSPW in organic soils. Four mesocosms placed in a greenhouse were randomly assigned with two treatments: 1) a moss carpet (Bryum pseudotriquetrum) and 2) graminoids (Carex aquatilis and Calamagrostis stricta). Transport of Na and NAs through peat was significantly delayed by sorption and diffusion in peat matrix. After two growing seasons of receiving OSPW, the graminoid plants continued to grow without showing stress from OSPW, while mosses showed a considerable decline in health. Microorganisms were more active under sedges than mosses and their activity varied over time either because of seasonal variation or as a consequence of variation in Na concentration. The findings of this study are limited due to the small number of replicates and the lack of a control, but represent a first step towards the creation of peatlands in the post-mined areas.

Techniques for restoring fen vegetation on cut-away peatlands in North America

ABSTRACT Question: Which restoration measures (reintroduction techniques, reintroduction timing and fertilization) best enable the establishment of fen species on North American cut-away peatlands? Location: Rivière-du-Loup peatland, southern Québec, Canada. Methods: In total, eight treatments which tested a combination of two reintroduction techniques, two reintroduction timings and the use of phosphorus fertilization were tested in a field experiment within a completely randomized block design. Results: Sphagnum transfer, a reintroduction technique commonly used for bog restoration in North America, was effective for establishing Sphagnum and Carex species. The hay transfer method, commonly used for fen restoration in Europe, was much less successful, probably due to questionable viability of reintroduced seeds. The treatments which included light phosphorus fertilization, had a higher Carex cover after three growing seasons. The timing of the reintroductions had no impact on the success of vegetation establishment. However, vegetation reintroduction should be carried out in the spring while the ground is still frozen to minimize other ecological impacts. Conclusions: The success of the diaspore reintroduction technique on small-scale units indicates that a large-scale restoration of fens using this technique is feasible. Nomenclature: Scoggan (1978) for vascular plants; Anderson (1990) for Sphagnum; Anderson et al. (1990) for other mosses.

Examining the peat-accumulating potential of fen vegetation in the context of fen restoration of harvested peatlands

Abstract: In order to focus efforts towards specific vegetation groups in fen restoration, knowledge of the peat-accumulating function of dominant fen species is critical. The decomposition rates of 3 species typical to undisturbed fens and 3 species that spontaneously colonize harvested fens were assessed. These species were incubated in both a restoration site (harvested fen) and an undisturbed fen to compare decomposition according to different environmental conditions. The average exponential decay coefficient (k) for all material types was slightly higher (circa 0.04·y-1 higher) in the harvested fen than those observed in the undisturbed fen. However, the litter type (leaves, roots/rhizomes, or bryophyte fragments) had the largest impact on the decomposition rates. The 2 tested bryophytes had lower k-values (between 0.14 and 0.11 for Polytrichum strictum and 0.06 for Sphagnum centrale) than the vascular plant litter (between 0.25 and 0.50). The annual primary production of the tested species was also measured to estimate the peat-accumulating capacity of each species. Scirpus cyperinus had an annual primary production that was 3 times higher (1500 g·m-2·y-1) than the other species (between 300 and 550 g·m-2·y-1). Estimates show that the harvested fen has a high peat-accumulating potential due to the high biomass production observed at this site. Nomenclature: Scoggan, 1978; Anderson, 1990; Anderson, Crum & Buck, 1990.

A conceptual framework for ecosystem restoration applied to industrial peatlands

Introduction The extraction of peat for fuel on an industrial basis started in the seventeenth century in eastern and northern Europe as the supply of wood for energy declined. The use of peat for energy in North America has always been small in scale. The demand for horticultural peat rose steadily after World War II on both continents (http://peatmoss.com/what-is-peat-moss/the-history-of-peat/). Currently, Europe and North America use peatmoss-peat extensively for landscaping, professional greenhouse production, hydrocarbon spills and waste water treatment. To date, in Canada, the main horticultural peat producers have impacted close to 20 000 ha. To place this into context, Canadas peatland extent is estimated to be around 125 000 000 ha with industrial activities mostly located on the southern margins of the peatland distribution. Most of the industrial peatlands are still in operation (16 000 ha), whereas close to 2000 ha have been restored according to the approach described below. With the rising awareness of goods and services provided by wetlands in the 1980–90s (Costanza et al. 1997), the international industrial peat sector recognised the impacts their activities had on peatland functions and developed a strategy for responsible peatland management. Several countries have since developed their own strategy and encourage the restoration of industrial peatlands (Clarke and Rieley 2010). For the case of Canada, peatland restoration is particularly driven by their main US horticultural clients, who demand responsible management of wetlands, driven by their interior policy on wetlands (NAWCA 1989). Based on two decades of trial-and-error experiments on restoring industrial peatlands, we have created a restoration framework. This framework draws on the ideas of assembly rules and restoration ecology. In this chapter, the framework is applied to restoring peatlands, but it should be applicable to the restoration of any ecosystem. Assembly rules and restoration ecology The union of assembly rules and restoration ecology should be beneficial for both areas of ecology (Keddy 1999; Temperton et al. 2004). Assembly rules are a helpful tool for restoration because, if the constraints of community membership are defined, restoration efforts can focus on manipulating these constraints to steer succession towards the desired community (Temperton et al. 2004). Restoration ecology has been criticised for being a haphazard collection of individual cases (Keddy 1999).

Foundations of Restoration Ecology

Mountain goats are an odd looking beast; a mixture between sheep and goats, their white coats and small curved horns give them a devilish appearance. They live in the cold Rocky Mountains and are emblematic of the region, but, as with many ungulate species, they are subject to controversy accused of decimating landscape on one hand and threatened by local extinction because they are valued as a trophy animal on the other. Much of this comes from a limited of understanding of their biology, ecology and behaviour and the lack of inclusion of science-based information in management. This book by Festa-Bianchet and Côté goes some way to overcoming this issue by presenting the results of a fascinating study of a population of mountain goats in the foothills of the Rocky Mountains in Canada. The study is one of a growing number that takes an approach which follows the life history of known individual animals to attempt an understanding of how variation in morphology, diet, physiology and behaviour between individuals affect fitness and population dynamics. The book summarises the output of 16 years study, much of it already published. Festa-Bianchet and Côté give insights into not only the evolution, ecology and behaviour of mountain goats but also gives a flavour of the difficulties of studying an animal in the harsh mountain environments of North America. I found much to ponder, for example, that, in this species, males and females lead very different lives, only coming together to mate. In many other ungulate species, including the members of the Caprinae, you would expect substantial differences in sexual dimorphism, but male and female mountain goats are difficult to tell apart; males are larger than females but their horns are very similar in size and shape. This may relate to differences in fighting strategies between mountain goats and many other Caprinae species but the question of the limited degree of sexual dimorphism in this species is still open. An important issue for management is the impact of hunting on population viability and the “quality” of the population. This is one area where this study gives insights that are not addressed by other individual-based studies of ungulates across the globe. Festa-Bianchet and Côté argue that poor regulation of hunting is a major threat to mountain goat populations across their range. The results of their study suggest that populations are particularly vulnerable if females are shot as they have a low recruitment rate and do not have a compensatory response in birth kid survival or adult survival in response to hunting. Also, the difficulty of accessing the terrain can mean that hunters target their activities on easily accessed populations threatening these populations because of limited dispersal and high site fidelity of the species. There is much else in the body of the book to interest and excite the reader however, I have to point out that there are a couple of limitations to the study. Firstly, the harsh winter conditions in the study area mean that the research only happens between May and September each year missing out on what could be a very important period of mountain goat mortality; secondly, the limited ability of the researchers to trap adult male mountain goats constrains their understanding of the behaviour, ecology, mating success and fitness of this sex. So who should be interested in reading the book? Firstly, researchers interested in the behaviour and ecology of ungulates; secondly, undergraduates who want to get a feeling for what fieldwork is like in tough conditions and how scientists try to overcome the limitations of the circumstances in which they work; and finally, wildlife managers who need a summary of how scientific insights can be brought to bear on the management of species that are vulnerable to overexploitation. Studies such as the one described in this book are rare, mainly because of the difficulties of sustaining funding in the face of administrative, political, personal and emotional vagaries of the academic world; Festa-Bianchet and Côté’s study has survived and the result is a book that demonstrates the value of long term data collected on individual animals not only for science but also for management. Long may this continue.