ScienceDaily (Jan. 12, 2012) — Wandering albatrosses have altered their foraging due to changes in wind fields in the southern hemisphere during the last decades. Since winds have increased in intensity and moved to the south, the flight speed of albatrosses increased and they spend less time foraging. As a consequence, breeding success has improved and birds have gained 1 kilogram. These are the results of the study of an international research team published in the latest issue of the Science journal. However, these positive consequences of climate change may last short if future wind fields follow predictions of climate change scenarios, researchers warn.
For this study, biologists had combined data on the duration of foraging trips and breeding success over the last 40 years, as well as foraging and body mass over the last 20 years of wandering albatross (Diomedea exulans) breeding in Crozet Islands. This archipelago lies approximately in the heart of the southern Indian Ocean (halfway between Madagascar and Antarctica). It belongs to the French Southern Territories and it is located in the windiest part of the Southern Ocean. The new findings are the result of an international research team from the French National Centre for Scientific Research (CNRS-CEBC) and the German Helmholtz-Centre for Environmental Research (UFZ).
Thanks to miniaturised tracking devices, researchers were able to track the foraging movement of albatrosses at a distance of 3500 kilometers from the colony. They found that albatross have altered their search patterns following changes in wind conditions over the past two decades. Females used increasingly more poleward and windy areas for foraging. As a consequence their travel speed increased while the total distance covered during foraging flights did not change. “This means that they spend less time at sea while incubating the egg and thus the breeding success increases” explains Dr. Henri Weimerskirch of the French National Centre for Scientific Research (CNRS-CEBC). Researchers were surprised that both females and males have increased their body mass in one kilogram, which corresponds approximately to one tenth of their total body weight. This could be not only a result of shorter incubation periods on the nest, but also an adaptation to windier conditions.
“The wandering albatross Crozet population has decreased as a result of adult mortality on longline fishing in subtropical waters, especially females since they favour warmer subtropical waters in the north compared to the more southerly distribution of males” says Dr. Maite Louzao Arsuaga, who has been modelling albatross movement from 2009 to 2011 at the UFZ. “Due to the changing wind conditions, females are now foraging in more southward areas where such fishing is not that widespread.” However, the positive effects of changing environmental conditions of the last decades will not last in the future. Climate scenarios predict that westerly winds will move even further south by 2080 and wandering albatrosses might have to fly further to find optimal conditions for flying.
The total population of the wandering albatross is currently estimated at around 8,000 breeding pairs. All populations have shown a decrease at some stage over the last 25 years. This endangered species is threatened primarily by incidental catch in fisheries, especially longline fishing at sea, whereas the introduction of alien species (such as rats or cats) are a key conservation threat for the species on breeding colonies. Additionally, the accumulation of anthropogenic debris such as plastic and fishing hooks on albatrosses have negative effects on their populations. Thus, it is important to continue with monitoring programs of population trends and distribution at sea, as well as to undertake effective conservation measures. The foraging habitat of wandering albatrosses is managed by more than one Regional Fisheries Management Organisations, which makes it difficult to implement conservation measures for the species.
The wandering albatross has fascinated people for centuries. With a wingspan of over three meters and a half, it is the largest seabird in the world, surpassing just the Andean condor (Vultur fulvus). This elegant sailor, which spends most of its life flying, breeds on remote subantarctic islands over the Southern Ocean. They travel thousand of kilometers searching for fish and cephalopods like squids, often following ships and feeding on offal. The plumage of wandering albatrosses is variable, whitening with age. The maximum known age is 55 years old. Since the rearing of chicks takes a whole year, they breed only every second year
Apart from the study published in the latest Science issue, the research team has identified the key marine areas for the conservation of wandering albatrosses in the southern Indian Ocean published in 2011 in the Journal of Applied Ecology. This study provided the first map to support the future development of a network of priority protected areas in the southern part of the Indian Ocean, which are based on habitat predictions. “Because the species has no natural enemies and is at the top of the food web, it is particularly well suited as an indicator of the health of marine ecosystems,” says Dr. Thorsten Wiegand from the UFZ, who supervised the work of Dr. Maite Louzao. “This could help not only a single species, but the underlying biodiversity associated with pelagic key habitats to protect Southern Ocean. Moreover, we have developed methods of habitat modelling broadly applicable and can be used to assess changes in species distribution within the current global change scenario.”
- H. Weimerskirch, M. Louzao, S. de Grissac, K. Delord.Changes in Wind Pattern Alter Albatross Distribution and Life-History Traits. Science, 2012; 335 (6065): 211 DOI: 10.1126/science.1210270
- Maite Louzao, David Pinaud, Clara Péron, Karine Delord, Thorsten Wiegand, Henri Weimerskirch. Conserving pelagic habitats: seascape modelling of an oceanic top predator. Journal of Applied Ecology, 2011; 48 (1): 121 DOI: 10.1111/j.1365-2664.2010.01910.x
ScienceDaily (Dec. 18, 2011) — By 2100, global climate change will modify plant communities covering almost half of Earth’s land surface and will drive the conversion of nearly 40 percent of land-based ecosystems from one major ecological community type — such as forest, grassland or tundra — toward another, according to a new NASA and university computer modeling study.
Researchers from NASA’s Jet Propulsion Laboratory and the California Institute of Technology in Pasadena, Calif., investigated how Earth’s plant life is likely to react over the next three centuries as Earth’s climate changes in response to rising levels of human-produced greenhouse gases. Study results are published in the journal Climatic Change.
The model projections paint a portrait of increasing ecological change and stress in Earth’s biosphere, with many plant and animal species facing increasing competition for survival, as well as significant species turnover, as some species invade areas occupied by other species. Most of Earth’s land that is not covered by ice or desert is projected to undergo at least a 30 percent change in plant cover — changes that will require humans and animals to adapt and often relocate.
In addition to altering plant communities, the study predicts climate change will disrupt the ecological balance between interdependent and often endangered plant and animal species, reduce biodiversity and adversely affect Earth’s water, energy, carbon and other element cycles.
“For more than 25 years, scientists have warned of the dangers of human-induced climate change,” said Jon Bergengren, a scientist who led the study while a postdoctoral scholar at Caltech. “Our study introduces a new view of climate change, exploring the ecological implications of a few degrees of global warming. While warnings of melting glaciers, rising sea levels and other environmental changes are illustrative and important, ultimately, it’s the ecological consequences that matter most.”
When faced with climate change, plant species often must “migrate” over multiple generations, as they can only survive, compete and reproduce within the range of climates to which they are evolutionarily and physiologically adapted. While Earth’s plants and animals have evolved to migrate in response to seasonal environmental changes and to even larger transitions, such as the end of the last ice age, they often are not equipped to keep up with the rapidity of modern climate changes that are currently taking place. Human activities, such as agriculture and urbanization, are increasingly destroying Earth’s natural habitats, and frequently block plants and animals from successfully migrating.
To study the sensitivity of Earth’s ecological systems to climate change, the scientists used a computer model that predicts the type of plant community that is uniquely adapted to any climate on Earth. This model was used to simulate the future state of Earth’s natural vegetation in harmony with climate projections from 10 different global climate simulations. These simulations are based on the intermediate greenhouse gas scenario in the United Nations’ Intergovernmental Panel on Climate Change Fourth Assessment Report. That scenario assumes greenhouse gas levels will double by 2100 and then level off. The U.N. report’s climate simulations predict a warmer and wetter Earth, with global temperature increases of 3.6 to 7.2 degrees Fahrenheit (2 to 4 degrees Celsius) by 2100, about the same warming that occurred following the Last Glacial Maximum almost 20,000 years ago, except about 100 times faster. Under the scenario, some regions become wetter because of enhanced evaporation, while others become drier due to changes in atmospheric circulation.
The researchers found a shift of biomes, or major ecological community types, toward Earth’s poles — most dramatically in temperate grasslands and boreal forests — and toward higher elevations. Ecologically sensitive “hotspots” — areas projected to undergo the greatest degree of species turnover — that were identified by the study include regions in the Himalayas and the Tibetan Plateau, eastern equatorial Africa, Madagascar, the Mediterranean region, southern South America, and North America’s Great Lakes and Great Plains areas. The largest areas of ecological sensitivity and biome changes predicted for this century are, not surprisingly, found in areas with the most dramatic climate change: in the Northern Hemisphere high latitudes, particularly along the northern and southern boundaries of boreal forests.
“Our study developed a simple, consistent and quantitative way to characterize the impacts of climate change on ecosystems, while assessing and comparing the implications of climate model projections,” said JPL co-author Duane Waliser. “This new tool enables scientists to explore and understand interrelationships between Earth’s ecosystems and climate and to identify regions projected to have the greatest degree of ecological sensitivity.”
“In this study, we have developed and applied two new ecological sensitivity metrics — analogs of climate sensitivity — to investigate the potential degree of plant community changes over the next three centuries,” said Bergengren. “The surprising degree of ecological sensitivity of Earth’s ecosystems predicted by our research highlights the global imperative to accelerate progress toward preserving biodiversity by stabilizing Earth’s climate.”
JPL is managed for NASA by the California Institute of Technology in Pasadena.
- Jon C. Bergengren, Duane E. Waliser, Yuk L. Yung. Ecological sensitivity: a biospheric view of climate change. Climatic Change, 2011; 107 (3-4): 433