Macrophysiology for a changing world

The Millennium Ecosystem Assessment (MA) has identified climate change, habitat destruction, invasive species, overexploitation and pollution as the major drivers of biodiversity loss and sources of concern for human well-being. Understanding how these drivers operate and interact and how they might be mitigated are among the most pressing questions facing humanity. Here, we show how macrophysiology--the investigation of variation in physiological traits over large geographical, temporal and phylogenetic scales--can contribute significantly to answering these questions. We do so by demonstrating, for each of the MA drivers, how a macrophysiological approach can or has helped elucidate the impacts of these drivers and their interactions. Moreover, we illustrate that a large-scale physiological perspective can provide insights into previously unrecognized threats to diversity, such as the erosion of physiological variation and stress tolerance, which are a consequence of the removal of large species and individuals from the biosphere. In so doing we demonstrate that environmental physiologists have much to offer the scientific quest to resolve major environmental problems.     

Protected areas: a prism for a changing world

The centrality of protected areas in biodiversity conservation has not changed over the past three decades, but we now know that biodiversity conservation represents a much more complex and dynamic picture than was once thought. In contrast to the earlier primarily aesthetic motivation (and still valid in its own right), the role of protected areas in biodiversity conservation is now widely accepted. Internationally, their importance has been recognized by the Convention on Biological Diversity and by the creation of intergovernmental funding agencies such as the Global Environmental Facility. As I discuss here, the rate of creation of new protected areas has increased rapidly to meet the need for a protected representative set of the ecosystems of the world. But that is only the start of the task.     

Bioerosion in a changing world: a conceptual framework

Bioerosion, the breakdown of hard substrata by organisms, is a fundamental and widespread ecological process that can alter habitat structure, biodiversity and biogeochemical cycling. Bioerosion occurs in all biomes of the world from the ocean floor to arid deserts, and involves a wide diversity of taxa and mechanisms with varying ecological effects. Many abiotic and biotic factors affect bioerosion by acting on the bioeroder, substratum, or both. Bioerosion also has socio‐economic impacts when objects of economic or cultural value such as coastal defences or monuments are damaged. We present a unifying definition and advance a conceptual framework for (a) examining the effects of bioerosion on natural systems and human infrastructure and (b) identifying and predicting the impacts of anthropogenic factors (e.g. climate change, eutrophication) on bioerosion. Bioerosion is responding to anthropogenic changes in multiple, complex ways with significant and wide‐ranging effects across systems. Emerging data further underscore the importance of bioerosion, and need for mitigating its impacts, especially at the dynamic land–sea boundary. Generalised predictions remain challenging, due to context‐dependent effects and nonlinear relationships that are poorly resolved. An integrative and interdisciplinary approach is needed to understand how future changes will alter bioerosion dynamics across biomes and taxa.     

Understanding effects of global change on river ecosystems: science to support policy in a changing world

This study explores the past, present and future ecological changes in the highest Mediterranean temporary pond (Omalos pond) in western Crete, Greece. Data from downcore pollen analysis (including pollen and spores from both aquatic vegetation, and terrestrial herbaceous, arboreal and shrub vegetation), modern vegetation monitoring and existing climate scenarios have been combined to provide a picture of the ecological changes in the pond over the last 13,600 years. Downcore pollen analysis throughout the last 13,600 years indicated the presence of species typical of Mediterranean Temporary Pond (MTP) habitats and suggested relatively drier conditions towards the present. The low number of non-native, cultivated species (such as herbaceous Trifolium and Plantago species) observed over this period suggested relatively low impact from crop agriculture, despite the increasing grazing pressure in the area. In the absence of independent proxies, we cannot reliably distinguish between natural and human-induced changes. The presence of aquatic Isoetes in the palaeo-record indicates the existence of an ephemeral pond in the area as early as the beginning of the Holocene suggesting resilience of the ecosystem over time. However, the degraded state of pollen in depths over 55 cm (i.e. 3600 year BP) increases the uncertainty of the interpretation. Currently, the pond holds 76 plant species belonging to 25 families. Therophytes and chamaephytes were the most frequent, suggesting a typical ephemeral habitat life form spectrum. Species richness was found to increase during spring surveys whereas the highest turnover was observed between summer surveys of consecutive years. Cluster analysis demonstrated a distinct zonation in four vegetation belts from the periphery to the centre of the pond which is typical of these environments. Modelling, based on two IPPC scenarios (A2 and B2), predicted relatively low climate change impacts on the pond’s hydroperiod for the next 100 years (i.e. a decrease of 16 and 24 days, respectively). This reduction in the hydroperiod of the pond will have an effect on the physiognomy and spatial extent of vegetation, particularly for the transitional belts between the core and its outer area, while it will exert more pressure on the pond as a water resource for sheep in the region. However, cumulative effects and complex interactions of climate-driven environmental changes and other anthropogenic disturbances might act synergistically to accelerate impacts in the future.     

Biodiversity matters in a changing world

It is now widely accepted that the climate of our planet is changing, but it is still hard to predict the consequences of these changes on ecosystems. The impact is worst at the poles, with scientists concerned that impacts at lower latitudes will follow suit. Canada has a great responsibility and potential for studying the effects of climate changes on the ecological dynamics, given its geographical location and its scientific leadership in this field. The 5th annual meeting of the Canadian Society for Ecology and Evolution was held in the International Year of Biodiversity, to share recent advances in a wide variety of disciplines ranging from molecular biology to behavioural ecology, and to integrate them into a general view that will help us preserve biodiversity and limit the impact of climate change on ecosystems.     

Biological diversity in a changing world

From the pioneering explorations of Joseph Banks (later a President of the Royal Society), to the present day, a great deal has been learnt about the extent, distribution and stability of biological diversity in the world. We now know that diverse life can be found even in the most inhospitable places. We have also learned that biological diversity changes through time over both large and small temporal scales. These natural changes track environmental conditions, and reflect ecological and evolutionary processes. However, anthropogenic activities, including overexploitation, habitat loss and climate change, are currently causing profound transformations in ecosystems and unprecedented loss of biological diversity. This series of papers considers temporal variation in biological diversity, examines the extent of human-related change relative to underlying natural change and builds on these insights to develop tools and policies to help guide us towards a sustainable future.     

The family in a changing world

Increasing numbers of young mothers in the work force, more and more children requiring extrafamilial care, high rates of divorce, lower rates of remarriage, increasing numbers of female-headed households, growing numbers of zero-parent families, and significant occurrences of child maltreatment are just some of the social indicators indicative of the family in a changing world. These trends and their consequences for children are described and then examined from the perspectives of microeconomic theory, the relative-income hypothesis, sex-ratio theory, and one form of modernization theory. The paper concludes with a preliminary examination of the added explanatory power provided by evolutionary theory.     

Trophic interactions in a changing world

Across the biosphere, rapid and accelerating changes in land use, climate and atmospheric composition driven primarily by anthropogenic forces are known to exert major influences on the productivity, biodiversity and sustainable provision of ecosystem goods and services. Thus far, many studies assessing the ecological consequences of global change have focussed on single trophic levels. However, understanding these changes and predicting their consequences may benefit from unravelling how interactions between primary producers, primary, and secondary consumers (plants, herbivores and carnivores) are being affected. Conservation and restoration may be improved when assessing species and their interactions on appropriate scales, while acknowledging that above- and belowground biota are ecologically linked. Selection pressures on one species may depend on others, so that species loss means more for diversity than just loss of a single taxon. It may also result in the loss of other species of the same or different trophic levels and in the dilution, or even loss, of various selection pressures. We review a number of discussions on trophic interactions in a changing world in relation to (i) the scale of ecosystem response to environmental change with emphasis on the soil subsystem, (ii) the linkage of above- and belowground subsystems and (iii) natural selection and the stability of community structure and ecosystem functioning. We discuss the need to bring together isolated sub-disciplines of ecology in order to understand the implications of global changes for ecosystem processes.

Zusammenfassung

In der gesamten Biosphäre üben schnelle und sich beschleunigende Veränderungen in der Landnutzung, des Klimas und der atmosphärischen Zusammensetzung, die vor allem durch anthropogene Kräfte angetrieben werden, größten Einfluss auf die Produktivität, die Biodiversität und die nachhaltige Bereitstellung von Ökosystemgütern und –leistungen aus. Bisher konzentrierten sich viele Untersuchungen, die ökologische Konsequenzen des globalen Wandels abschätzen, auf einzelne trophische Level. Das Verständnis dieser Veränderungen und die Vorhersage ihrer Konsequenzen kann jedoch davon profitieren, dass enträtselt wird, wie die Interaktionen zwischen den Primärproduzenten und den primären und sekundären Konsumenten (Pflanzen, Herbivore und Karnivore) beeinflusst werden. Naturschutz und –wiederherstellung kann verbessert werden, wenn die Arten und ihre Interaktionen auf angemessenen Skalen und unter Berücksichtigung, dass ober- und unterirdische Biota ökologisch miteinander verbunden sind, eingeschätzt werden. Der Selektionsdruck auf eine Art kann von anderen Arten abhängen, so dass der Verlust einer Art mehr für die Diversität bedeutet als nur den reinen Verlust eines Taxons. Er kann ebenso den Verlust anderer Arten des gleichen oder eines anderen trophischen Levels zur Folge haben sowie die Abschwächung oder sogar den Verlust von verschiedenen Selektionsdrücken. Wir geben einen Überblick über die Diskussionen zu trophischen Interaktionen in einer sich verändernden Welt in Bezug auf (i) die Skala der Ökosystemantwort auf Umweltveränderungen mit Betonung des Bodensubsystems, (ii) die Verbindung zwischen ober- und unterirdischen Subsystemen und (iii) die natürliche Selektion und die Stabilität der Gemeinschaftsstruktur sowie der Ökosystemfunktion. Wir diskutieren die Notwendigkeit isolierte Subdisziplinen der Ökologie zusammen zu führen, um die Implikationen des globalen Wandels für Ökosystemprozesse zu verstehen.     

Mate choice in a changing world

Human activities by altering environmental conditions are influencing the mate choice of animals. This is by impacts on: (i) the production and expression of traits evaluated by mate choosers; (ii) the transmission of information about potential mates to choosers; (iii) the reception and processing of the information by choosers; and (iv) the final mate choice. Here, I first discuss how these four stages of the mate‐choice process can be altered by environmental change, and how these alterations, in turn, can influence individuals, populations, and communities. Much evidence exists for human‐induced environmental changes influencing mate choice, but the consequences for the fitness of courters and choosers are less well known, and even less is known about the impact on population dynamics, species interactions and community composition. More evidence exists for altered mate‐choice systems influencing interspecific matings and thereby community composition and biodiversity. I then consider whether plastic adjustments and evolutionary changes can rescue adaptive mate‐choice systems, and reflect on the possibility of non‐adaptive mate‐choice systems becoming less maladaptive under environmental change. Much evidence exists for plastic adjustments of mate‐choice systems, but whether these are adaptive is seldom known, as is the contribution of genetic changes. Finally, I contemplate the possibility of mate‐choice systems rescuing populations from decline in changing environments. I explain how this is context dependent with both positive and negative outcomes possible. In summary, while much evidence exists for human‐induced environmental changes influencing mate‐choice systems, less is known about the consequences for ecological and evolutionary processes. Considering the importance that mate choice plays in determining individual fitness and population viability, the effects of environmental change on mate‐choice systems should be considered in studies on the ecological and evolutionary consequences of human disturbances to habitats.