This book is the first snapshot of the state of scientific knowledge on the Prince Edward Islands since the Van Zinderen Bakker-led baseline volume of 1971, and, given the research efforts there over the 40 years, is long overdue. The first chapter by the volume editors sets the scene in a very topical way by highlighting major global themes and environmental drivers and then placing the research from the islands into this context, thus establishing a well argued case for the islands as useful model systems and the science outcomes of more general value. The authors are correct in recognizing that the scientific output from these islands has been exceptionally high over these 40 years.
The next three chapters on oceanography, climate and climate change, and geology and geomorphology continue the theme of scene setting and synthesis. The le Roux chapter is an excellent description of current knowledge of the islands' climate in context, but extends beyond synthesis with one of the best descriptions of the mechanisms driving climate change, including both the Semi-Annual Oscillation and the Southern Annual Mode. It is refreshing to read such a deep understanding of climate and climate change and I predict that this chapter will become a standard citation for any sub-Antarctic climate or ecological studies. The oceanography and geology/geomorphology chapters unfortunately are somewhat less accessible, and are also hampered by poor illustrations. However, substantive information can still be gleaned from them including details of a rise in sea surface temperature around the islands of 1.4°C over the last 50 years and the importance of the role of animals in shaping the landscape of these islands. For example, it was fascinating to that read that prions and petrels can excavate 5 to 9 m3/ha and that for the islands this collectively exceeds over 60 000 m3 of peat moved through burrowing activity.
The oceanography chapter, coupled with chapters on biology in the oceanic environment, pelagic predators and oceanic nutrient cycling, do convey successfully the complex interactions associated with an island ecosystem sandwiched between the Sub-Antarctic Front (SAF) and Antarctic Polar Front and interacting with the terrestrial environment and the “island mass effect”. Collectively the question of how millions of top predators are supported in what are generally low nutrient waters is handsomely answered. The last pages of the McQuaid & Froneman chapter in conjunction with the detailed description of population directions in the pelagic predator chapter leaves a chilling aftertaste as they review recently documented decadal changes in the marine environment, including a reduction by 20% in the contribution of Antarctic species to local zooplankton composition and a concomitant increase in subtropical species. The local shift in the primary carbon source of the shrimp Nauticus marionis reflects an overall decrease in regional primary productivity. This is of concern as N. marionis is a major food source of inshore feeders including rockhopper and gentoo penguins and Crozet shags, which have all experienced substantial declines in their island populations. Such changes are related to shifts in the position of the SAF associated with global climate change.
Smith & Froneman successfully link the surrounding sea to the terrestrial system through their discussions of marine-derived nutrient subsidies in the terrestrial realm from seal and sea bird activity. Emphasising the land/sea boundary theme of the book, this chapter creates an effective segue into the terrestrial chapters, beginning with Smith's second chapter on terrestrial nutrient cycling where he conveniently summarises his seminal 1980–90s papers and the aquatic ones of Grobelar from the 1970s describing the intricate chasing of prime nutrients through key habitats. I greatly appreciate now having all the information in one place with the added bonus of wisdom gained with the passage of time. Considering the current climate changes occurring on the island, I look forward to an update on how the significant drying on the island has impacted nutrient cycling. Finally, Smith provides a salient reminder of how alien species, particularly from different functional groups, can impact across trophic levels and ecosystem processes, highlighting the way in which mice are now the cardinal determinants of macroinvertebrate population dynamics on Marion Island with effects on the rates of nutrient release and, in turn, on plant productivity.
Three middle chapters build up a picture of islands in which decades of carefully crafted research have yielded substantial knowledge of terrestrial ecosystem structure and function, including spatial variation at multiple levels and predicted pathways of plant communities with various future climate change scenarios. Furthermore, there has been a critical evaluation of the islands' biogeography and hints at what will be the outcome of future research, in particular an understanding of the evolutionary pathways of the islands' biota. The penultimate chapters describe the islands' conservation and management setting and include a brief, though delightful foray into the islands' human history, complete with reflections of how South African history has been mirrored in the microcosm of sub-Antarctic station life. The final chapter focuses on various levels and types of change, in both marine and terrestrial ecosystems, as well as complexity across realms.
So does this book belong in your library? Yes if you work at all with terrestrial and marine sub-Antarctic and Antarctic ecosystems, but also if you work in ecosystems in general. The book demonstrates the worth of cumulative detail in scientific investigations, as well as the importance of long term ecological research and asking cutting edge questions. It also reflects the value of continuity of research access to such remarkable sentinels of change as the Prince Edward Islands, and their value through postgraduate training and research in the education of younger scientists. The volume is beautifully produced, a very reasonable price and a major tangible outcome of the investment in sub-Antarctic science, an effort of which South Africa can be justifiably proud.
