Gene immigration continues despite fragmented landscapes

Dec 06, 2013
Gene immigration continues despite fragmented landscapes
Calothamnus quadrifidus ssp teretifolious is a woody shrub, two to four metres tall that flowers profusely in spring and winter and is an important source of nectar for birds. Credit: WikiMedia Commons

Human activity like clearing land for agriculture and mining does not threaten the ability of some plants to share genes via pollen carried by birds.

That's the finding of a recent study by WA researchers investigating gene flow in the rare endemic shrub Calothamnus quadrifidus ssp teretifolious in Western Australia's South West region.

Department of Parks and Wildlife research scientist Jane Sampson says many past studies in plant have come from America and Europe and the general 'rules' they produce around species fragmentation leading to genetic isolation and reductions in diversity and evolutionary potential don't always apply to Australian species.

"We have a lot of species that occur naturally in small isolated populations; that's just the nature of our landscape, so a lot of our species have been naturally fragmented for a long time," Dr Sampson says.

"With new genetic techniques, we can determine the source of pollen in seed crops, just like paternity analyses in humans.

"We found that the movement of pollen by birds was similar in fragmented and intact vegetation and the historical connectivity between populations has not been impacted by land clearing.

"So it is important to look after all patches of remnant vegetation in agricultural systems because all vegetation helps maintain connections across the landscape."

Calothamnus quadrifidus ssp teretifolious is a woody shrub, two to four metres tall that flowers profusely in spring and winter and is an important source of nectar for birds.

Dr Sampson says genetics theory also suggests that 'in-breeders' or plants that self pollinate like Calothamnus quadrifidus ssp teretifolious build up 'genetic load' in their populations creating an 'evolutionary dead-end in terms of breeding systems'.

But this wasn't the case in the research, providing evidence for maintaining genetic diversity and showing it is important to understand the biology of local species that can be different to those elsewhere in the world.

The study surveyed a 50sq metre area near Busselton. Two groups of four populations 19km apart were selected ranging from intact to highly degraded.

Leaf material was collected from adult plants from each of the eight populations to assess .

Seed capsules collected from 10 randomly selected plants were dried, germinated and grown in a glasshouse for one month before tissue was harvested for DNA extraction.

The findings are detailed in a report in the journal Heredity titled 'Contemporary pollen-mediated gene immigration reflects the historical isolation of a rare, animal-pollinated shrub in a fragmented landscape'.

Explore further: Urban bushland vital to Perth's birds

add to favorites email to friend print save as pdf

Related Stories

Urban bushland vital to Perth's birds

Nov 20, 2013

In a unique study of Perth and its surrounds, researchers have found the fragmentation of natural bushland is linked to an alarming decline in the numbers of native land birds.

Grazers and pollinators shape plant evolution

Oct 21, 2013

It has long been known that the characteristics of many plants with wide ranges can vary geographically, depending on differences in climate. But changes in grazing pressure and pollination can also affect the genetic composition ...

How does inbreeding avoidance evolve in plants?

Jun 10, 2013

Inbreeding is generally deleterious, even in flowering plants. Since inbreeding raises the risk that bad copies of a gene will be expressed, inbred progeny suffer from reduced viability.

Recommended for you

Alaska refuge proposes killing invasive caribou

1 hour ago

Federal wildlife officials are considering deadly measures to keep an Alaska big game animal introduced more than 50 years ago to a remote island in the Aleutians from expanding its range.

Five ways to stop the world's wildlife vanishing

10 hours ago

Full marks to colleagues at the World Wildlife Fund and the Zoological Society of London for the Living Planet Report 2014 and its headline message which one hopes ought to shock the world out of its com ...

User comments : 0