The phrenologist’s guide to ecological competence

Since Darwin, scientists have been theorizing as to why there is variation in brain size between species and individuals. Does a larger brain, in say humans, indicate advanced cognitive abilities and complex language processing? Or is a smaller brain, such as the Olive-backed thrush’s, adapted to weigh less to accommodate lengthy flights?

In psychology, the field of phrenology has generally been dissolved, and with it, the idea that variations in brain size could indicate differences in intelligence, creativity or personality between humans. In the field of biology, however, scientists are discovering that brain variation across species might actually be linked to ecological competence. In this case, ecological competence describes the efficiency of a species to engage in ecological processes—such as flexible foraging abilities or advanced spatial memory for migration.

Read More

From the Community: Pika population sees a boost, birds not spreading West Nile and five women honored for their role as environmentalists

Pika found to be flourishing in the Sierra Nevada region, bird migration patterns suggest mosquitoes are to blame for spreading West Nile and mice courtship rituals could shed light on autism. Here are news stories and studies on ecological science from the first week in March.

Read More

Can birds affect tree growth?

Growing conditions, such as water and nutrient supply, are the major determinates of tree growth, but insectivorous birds can also play an important role, say scientists in a study published in the January issue of Ecology. Under the right conditions, birds contribute to whole tree growth by preying on herbaceous arthropods, such as leafhoppers, caterpillars and grasshoppers…

Read More

Laser-imaging bird habitats

A paper out in the October issue of Ecological Applications puts forth a new use for light detection and ranging technology, or LiDAR: the prediction of bird habitats. LiDAR technology uses laser imaging techniques to develop maps of forest vegetation structure by sending laser beams from aircrafts that fly over a study area. In this case, the scientists sampled the Cosumnes River Preserve in central California.  They then can use known data about bird habitat preferences to predict the diversity and abundance of birds in the area.  Said Joshua Viers, a researcher at UC Davis: By combining this advanced imaging technology with traditional field research, we are able to measure and predict ecosystem components in unprecedented ways. Not only can we provide managers with very detailed information about ecosystem services such as carbon storage and its associated biodiversity, but we can do so over very large areas. Not to mention saving graduate students months of painstaking vegetation sampling. Read the rest of the article here. Seavy, N., Viers, J., & Wood, J. (2009). Riparian bird response to vegetation structure: a multiscale analysis using LiDAR measurements of canopy height Ecological Applications, 19 (7), 1848-1857 DOI:...

Read More

The state of the union’s birds

A comprehensive analysis of the current condition of birds in the U.S. was released yesterday by The Nature Conservancy, USGS, the Audubon Society, the Cornell Lab of Ornithology and many other non-profit groups. Dubbed The State of the Birds, the document reports that of the nation’s approximately 800 bird species, 67 are federally listed as endangered, 184 are of conservation concern and many others are declining due to dwindling habitat. The report highlights precipitous declines in Hawaiian birds, where introduced predators have decimated native bird populations. Seabirds and shorebirds are also suffering from pollution, overfishing and warming oceans, according to the report, and lack of management in arid lands and grasslands have led to neglect and decline in birds adapted to these habitats. On the other hand, Wetland birds are shown to be quite resilient to disturbance. The report draws attention to several successful conservation efforts, such as for the bald eagle and peregrine falcon, and emphasizes the need for conservation programs tailored to threatened species. The report brings together data from three surveys that include biologists and citizen scientists: the North American Breeding Bird Survey, administered by the U.S. Geological Survey and Canadian Wildlife Service; the Christmas Bird Count, conducted by the National Audubon Society; and the Waterfowl Breeding Population and Habitat Survey, from the U.S. Fish and Wildlife Service and Canadian Wildlife Service. Listen to NPR’s All Things Considered story about the...

Read More

Climate change may reorganize Western fauna

Bioclimatic models attempt to draw correlations between species distributions and climate patterns.  As ecologists and climatologists hone these models, they become a useful tool for predicting future species distributions based on projected climate patterns. In the March issue of Ecology, Joshua Lawler of the University of Washington and his colleagues undertook a huge task: using a bioclimatic model, they estimated the effects of climate change on future species ranges of almost 3000 species of birds, mammals and amphibians in the Western hemisphere. Their comprehensive survey revealed that some areas could experience a 90 percent change in species representation. The authors conclude that “as a result of climate change, many areas in the western hemisphere will likely experience a significant reorganization of their vertebrate fauna over the coming century.” Some of these largest shifts have also been found to be in areas of high conservation concern, such as rainforests in the Bahia region of Brazil. While this might initially seem fortuitous, since funding may already be in place to conserve these areas, the authors point out that under this climate change scenario, there may be little we can do to abate these drastic faunal changes. Bioclimatic models are useful as a first step, but as the authors concede, they only correlate distributions with climate variables (e.g. temperature, air moisture, precipitation), and thus don’t take into account species interactions, habitat requirements and evolution of animals.  Especially in the case of amphibians, which have specific hydrological and habitat needs, these factors play a huge role in distributions.  Sadly, even without these ecological factors, the bioclimatic models predict that amphibians’ ranges will be the most affected of any group tested. Add in the ecological factors, and our frog and salamander friends have a very grim outlook. Read more here; subscribers can access the full paper. Joshua J. Lawler, Sarah L. Shafer, Denis White, Peter Kareiva, Edwin P. Maurer, Andrew R. Blaustein, Patrick J. Bartlein (2009). Projected climate-induced faunal change in the Western Hemisphere Ecology, 90 (3), 588-597 DOI:...

Read More

To fly or not to fly?

Evolution can do funny things. Like producing the amazing feat of flight in a lineage of reptiles, which over time led to an adaptive radiation seldom rivaled in the history of animals. And then producing, in some 30 species of birds, the loss of the adaptation altogether. It would seem a ridiculous thing to do, to give up the power of flight, when you can fly. Certainly, if I could fly, I wouldn’t bother giving it up. That’s Rory Wilson, a professor of aquatic biology at the University of Wales Swansea. He’s pictured here with his first love and the subject of his Ph.D.: the African penguin. His most recent work gets up-close and personal with another flightless bird, the Galápagos cormorant, sometimes known as – you guessed it – the flightless cormorant. Wilson and his colleagues wondered what led this bird to lose the ability to fly when none of the other 60 waterbirds in its order – including pelicans, frigatebirds and boobies – have done the same.  Listen to Dr. Wilson discuss why some birds have evolved flightlessness in this podcast, the November installment of ESA’s Field Talk series. In birds, flight most likely originated as an escape response. Reptilian predecessors to modern-day birds would scamper away from predators, leading to the evolution of wings, feathers and muscles that lifted the animals off the ground, much to the chagrin of frustrated four-legged carnivores. Once they took to the air, the resourceful birds then co-opted this adaptation for other functions to boost their survival, such as traveling much greater distances in search of food. In the Galápagos islands, though, the situation is a bit different. There are no terrestrial predators, so using flight as an escape response isn’t important. The warm Pacific water and nutrient upwelling surrounding the Galápagos also make the coasts rich in seafloor prey, potentially reducing the need to travel great distances to find food. Wilson’s team tested this idea by tagging 95 birds with GPS loggers and time-depth recorders to get a sense of their position and movement in the water over a 24-hour period. Sure enough, the birds routinely dove in shallow waters at depths of only 20 percent of their deepest dives. The combination of release from predation and the ability to find consistent food close to shore led to these birds kicking their flying habit in favor of a streamlined body suited for diving. Though his research is motivated by the love of these flightless birds, the new object of Wilson’s affection is of the electronic kind. He hopes that the loggers his team uses can someday be made small and...

Read More