Ecology Buys Time for Evolution: Climate Change Disrupts Songbird's Timing Without Impacting Population Size (Yet)

Apr. 25, 2013 — Songbird populations can handle far more disrupting climate change than expected. Density-dependent processes are buying them time for their battle. But without (slow) evolutionary rescue it will not save them in the end, says an international team of scientists led by the Netherlands Institute of Ecology (NIOO-KNAW) in Science this week. 

Yes, spring started late this year in North-western Europe. But the general trend of the four last decades is still a rapidly advancing spring. The seasonal timing of trees and insects advance too, but songbirds like Parus major, or the great tit, lag behind. Yet without an accompanying decline in population numbers, it seems, as the international research team shows for the great tit population in the Dutch National Park the Hoge Veluwe. 

"It's a real paradox," explain Dr Tom Reed and Prof Marcel Visser of the Netherlands Institute of Ecology. "Due to the changing climate of the past decades the egg laying dates of Parus major have become increasingly mismatched with the timing of the main food source for its chicks: caterpillars. The seasonal timing of the food peak has advanced over twice as fast as that of the birds and the reproductive output is reduced. Still, the population numbers do not go down." On the short term, that is, as Reed, Visser and colleagues from Norway, the USA, and France have now calculated using almost 40 years of data from this songbird. 

The solution to the paradox is that although fewer offspring now fledge due to food shortage, each of these chicks has a higher chance of survival until the next breeding season. "We call this relaxed competition, as there are fewer fledglings to compete with," first author Reed points out. Out of 10 eggs laid, 9 chicks are born, 7 fledge and on average only one chick survives winter. That last number increases with less competitors around. 

Continued: http://www.sciencedaily.com/releases/2013/04/130425142348.htm

Symbiotic survival of rare birds and rain forests

On the coast of Ecuador, along the Pacific Ocean, on the western side of the Andes Mountains, lies the Choco rain forest. Here, Jordan Karubian, his students and local residents, whom he’s enlisted as “environmental ambassadors,” study an endangered species of bird — the long-wattled umbrellabird.
Karubian, an assistant professor of ecology and evolutionary biology at Tulane University, is looking at how the long-wattled umbrellabird eats the fruits of rain forest trees and disperses their seeds. “The trees depend upon that dispersal in order to propagate and replace themselves,” says Karubian.

He is researching the mating habits, seed-dispersal activities and migratory patterns of birds in Ecuador, Australia, Papua New Guinea and the Gulf South of the United States.

The birds that Karubian studies dwell in fragile ecosystems that are in peril. And he has discovered that to have a lasting impact on protecting the birds and their habitats from disappearance, he must do more than function as a traditional researcher.
Continued: http://tulane.edu/news/newwave/092812_karubian.cfm

Sea remains key to survival for migrating birds

NILAND — It began as an accident — a huge inland lake created more than 100 years ago when an irrigation-canal breach flooded a lonely corner of California desert with rushing Colorado River water.

But despite its unplanned start, the Salton Sea now serves a crucial ecological purpose.

It’s one of the last rest stops and breeding grounds left for millions of migrating birds, representing more than 400 species, that travel the Pacific Flyway — a bird superhighway that runs the western length of North America.

The birds, some of which are already endangered, rely on the Salton Sea’s tilapia-filled waters to survive as wetlands, rivers and lakes elsewhere have been lost to development in the past century. Experts have warned for years that more species would see their numbers plummet — with more becoming endangered and even extinct — if nothing is done to curb the rising salinity at the sea.

“Tilapia are the last game fish in the sea. If we hit their salt limit — and I think it will be soon — suddenly they are all going to go belly up in a short period of time,” University of Redlands Professor Timothy Krantz, an expert on the troubled sea, said last week. “And talk about a stink — that’s not going to be a pretty picture at all.”

Birds flying across the hemisphere feed on those fish at the sea, essentially a large oasis planted favorably in the middle of the desert. According to the U.S. Fish and Wildlife Service, 70 percent of all bird species in California are seen at the Salton Sea’s waters and one third of all bird species that breed in the state breed there.


Continued: http://www.mydesert.com/article/20120923/NEWS0701/309230036/Sea-remains-key-survival-migrating-birds?nclick_check=1