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The Daily Barometer: Researchers Study Effects Of Forest Fragmentation On Hummingbird Behavior

The Daily Barometer | Nov. 6, 2013 2:36 a.m. | Updated: Nov. 6, 2013 10:55 a.m.

Contributed By:

Dacotah-Victoria Splichalova

Hummingbirds flitting through the fragmented forests of Costa Rica have caught the attention of Oregon State University researchers.

Matthew Betts and Adam Hadley of the Betts Laboratory and the College of Forestry are both landscape ecologists whose research has primarily revolved around birds.

Betts and Hadley investigate the effects of habitat loss and fragmentation of species across 37 distinct isolated patches of forest in Costa Rica, seeking an understanding of how forest fragmentation affects pollination services.

Hummingbirds take on the role of “the pollinator,” wherein there exists a careful plant and pollinator interaction. The major goal of the group’s research is to examine how landscape changes are affecting the hummingbirds as pollinators.

The research involves a translocation study to see what the difference was between hummingbird’s journey across forests that were either fragmented or not.

“Interestingly, we discovered that the hummingbirds arrived at their pollination sites in the exact same amount of time, which is kind of amazing,” said Sarah Frey-Hadley, a doctoral researcher and logistical coordinator of the hummingbird research within the Betts lab.

The research team found that when the hummingbirds were traveling within the fragmented forests, the birds elected to take a considerably squigglier route to arrive at their final destination in order to avoid crossing large open gaps of forest patches.

“It shows that forest fragmentation does indeed alter the hummingbirds’ movement patterns,” Frey-Hadley said.

The Betts team also will collect the stiles (female part of the plant) of the heliconia flower, a bright red inflorescence that the hummingbird is highly attracted to for its beauty, nectar and shape.

Hadley discovered that overall seed sets (the number of seeds produced by flowers) were lower in the smaller, more fragmented forest patches than in non-fragmented patches.

The data implies that there’s some limitation occurring.

Hadley hypothesized that it’s potentially the quality of the pollen that’s being brought to the smaller forest patches by the hummingbirds, and perhaps the hummingbirds may not be visiting as many plants, fostering less-diverse pollen for the flowers — due to the fact that the hummingbirds do not want to cross the largely exposed patches of forest.

Partnering with the Organization for Tropical Studies and Las Cruzas Biological Station in Costa Rica, Hadley began carrying out field research on the hummingbird project with the Betts Lab in 2008 at the start of his Ph.D.

At that time, the group proved to be successful pioneers in placing the very first VHF radio transmitters on the hummingbirds to monitor their pollination routes in Costa Rica.

“No one even knew it worked at the time,” Hadley said. “We needed a large pollinator for the size of the transmitter. We couldn’t just place a transmitter on a tiny little bee … and from this collected data, we could then investigate a lot of the pollination concerns, which relates to systems here, like the pollination activity of bumblebees.”

Data from the radio transmitters has provided the group with the ability to track the actual movements of the hummingbirds, whereas with most pollinators, until recently, researchers had not been able to track movement patterns.

“The information we’ve collected informs on a lot of the processes, which are important over larger areas, like the forest and agricultural systems we have here, locally,” Hadley said.

In addition to radio transmitters, Betts research team member Evan Jackson, a doctoral candidate, has recently implemented the use of RFID tags or “PIT” tags on the hummingbirds.

The tags are about the size of a grain of rice. It’s the same technology that people use with pet microchips. Jackson investigates what kind of habitats the hummingbirds will or won’t use.

The Betts research team facilitates an educational outreach project with 11 local Corvallis schools.

“The conservation of natural habitats is important to be made aware (of),” Hadley said. “When habitats are altered or disturbed, we see the affect it has on the hummingbirds, but also on the plants that they are responsible for pollinating.”

Dacotah-Victoria Splichalova

Science reporter


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