Search

Warmer winters alter the dynamics of a local bird population and reduce immigration rate due to density-dependent feedback., Climate change will affect the population dynamics of many species, yet the consequences for the long-term persistence of populations are poorly understood. A major reason for this is that density-dependent feedback effects caused by fluctuations in population size are considered independent of stochastic variation in the environment. We show that an interplay between winter temperature and population density can influence the persistence of a small passerine population under global warming. Although warmer winters favor an increased mean population size, density-dependent feedback can cause the local population to be less buffered against occasional poor environmental conditions (cold winters). This shows that it is essential to go beyond the population size and explore climate effects on the full dynamics to elaborate targeted management actions.

The development of human civilisations has occurred at a time of stable climate. This climate stability is now threatened by human activity. The rising global climate risk occurs at a decisive moment for world development. World nations are currently discussing a global development agenda consequent to the Millennium Development Goals (MDGs), which ends in 2015. It is increasingly possible to envisage a world where absolute poverty is largely eradicated within one generation and where ambitious goals on universal access and equal opportunities for dignified lives are adopted. These grand aspirations for a world population approaching or even exceeding nine billion in 2050 is threatened by substantial global environmental risks and by rising inequality. Research shows that development gains, in both rich and poor nations, can be undermined by social, economic and ecological problems caused by human-induced global environmental change. Climate risks, and associated changes in marine and terrestrial ecosystems that regulate the resilience of the climate system, are at the forefront of these global risks. We, as citizens with a strong engagement in Earth system science and socio-ecological dynamics, share the vision of a more equitable and prosperous future for the world, yet we also see threats to this future from shifts in climate and environmental processes. Without collaborative action now, our shared Earth system may not be able to sustainably support a large proportion of humanity in the decades ahead.

This book focuses on the influence of climate variability on the marine ecosystems of the North Atlantic. The ecological impact of climate variability on population dynamics is addressed at the full range of trophic levels, from phytoplankton through zooplankton and fish to marine birds. Climate effects on biodiversity and community structure are also examined. The book discusses what is currently known about how climate affects the ecological systems of the North Atlantic, and then places these insights within a broader ecological perspective. Many of the general features of the North Atlantic region are also seen in other marine ecosystems as well as terrestrial and freshwater systems. The final section of the book makes these generalities more explicit, so as to stimulate communication and promote co-operation amongst researchers who may previously have worked in semi-isolation. The book comprises five main sections: background (general introduction, atmospheric and ocean climate of the North Atlantic, and modelling methodology), plankton populations (phytoplankton and zooplankton), fish and seabird populations, community ecology (phytoplankton, benthos and fish), and the final section consisting of six commentaries from scientists working in areas outside the North Atlantic marine sector. In order to enhance integration, a series of introductions link chapters and sections. Throughout the book, numerous examples highlight different aspects of ecology-climate interactions. They document recent progress and illustrate the challenges of trying to understand ecological processes and patterns in the light of climate variations.

The dynamics of Canadian lynx ( Lynx canadensis ) abundance are geographically structured according to the influence of large-scale climatic regimes. Here we demonstrate that this structuring matches zones of differential snow conditions, in particular surface hardness, as determined by the frequency of winter warm spells. Through a modified functional response curve, we show that various features of the snow may influence lynx interaction with its main prey species, the snowshoe hare ( Lepus americanus ). This study highlights the importance of snow, and exemplifies how large-scale climatic fluctuations can mechanistically influence population biological patterns.

Whereas the El Nino Southern Oscillation (ENSO) affects weather and climate variability worldwide, the North Atlantic Oscillation (NAO) represents the dominant climate pattern in the North Atlantic region. Both climate systems have been demonstrated to considerably influence ecological processes. Several other large-scale climate patterns also exist. Although less well known outside the field of climatology, these patterns are also likely to be of ecological interest. We provide an overview of these climate patterns within the context of the ecological effects of climate variability. The application of climate indices by definition reduces complex space and time variability into simple measures, 'packages of weather'. The disadvantages of using global climate indices are all related to the fact that another level of problems are added to the ecology-climate interface, namely the link between global climate indices and local climate. We identify issues related to: (i) spatial variation; (ii) seasonality; (iii) non-stationarity; (iv) nonlinearity; and (v) lack of correlation in the relationship between global and local climate. The main advantages of using global climate indices are: (i) biological effects may be related more strongly to global indices than to any single local climate variable; (ii) it helps to avoid problems of model selection; (iii) it opens the possibility for ecologists to make predictions; and (iv) they are typically readily available on Internet.

Climate influences a variety of ecological processes. These effects operate through local weather parameters such as temperature, wind, rain, snow, and ocean currents, as well as interactions among these. In the temperate zone, local variations in weather are often coupled over large geographic areas through the transient behavior of atmospheric planetary-scale waves. These variations drive temporally and spatially averaged exchanges of heat, momentum, and water vapor that ultimately determine growth, recruitment, and migration patterns. Recently, there have been several studies of the impact of large-scale climatic forcing on ecological systems. We review how two of the best-known climate phenomena—the North Atlantic Oscillation and the El Niño–Southern Oscillation—affect ecological patterns and processes in both marine and terrestrial systems.

Despite evidence of significant impacts from climate change, relatively few published papers in ecology, conservation biology, and biodiversity research deal with marine systems. This stark fact motivated a recent colloquium, hosted by the Advanced Study Program (ASP) at the National Center for Atmospheric Research (NCAR). The goal was to encourage graduate students to undertake research studies on understanding and predicting global climate variability and its impacts on marine ecosystems. An invited group of 18 international experts worked closely with 26 students from the climate, marine ecosystem, and impact communities.