Is plant diversity on the skids? The scales of biodiversity loss

Paraguay2bImagine you want to monitor changes in plant diversity, to see whether diversity is increasing or decreasing over time. What spatial scale would you study?

Would you search for changes at the global scale, or at continental, regional or local scales? More importantly, would you expect to see the same trend or different trends if you examined changes at many scales?

At the global scale, biological diversity on Planet Earth is on the skids. Thousands of species face extinction and over a thousand hectares of forest are cleared every hour. Species diversity is falling because species are going extinct faster than new species can evolve. And we’re causing it.

At the continental scale, we see the opposite pattern. Continue reading

Monitoring ecological change: a view from the streets

1 Street View Young Red ExoticImagine you live in the year 2063. You want to understand how the distribution of tree species changed in the past 50 years, to help you to assess the impacts of climate change.

What kind of data would you wish you had from 2013?

Let’s brain-storm a few ideas. I’m sure it’d be helpful if, back in 2013, people had recorded the distribution of plants along transects that criss-crossed the countryside, crossing the wet-to-dry climate gradient. This information would allow you to see which species expanded, contracted or migrated during the period, and how these changes related to changes in rainfall. Continue reading

Taking stock of fencing

The exotic grass, Wild Oats (Avena barbata) is abundant in an ungrazed, fenced plot at Terrick Terrick National Partk.

The exotic grass Wild Oats (Avena barbata) dominates a fenced plot at Terrick Terrick National Park.

Stock grazing has reduced the conservation value of many native grasslands and woodlands in southern Australia. Not surprisingly, we often remove stock to help restore degraded areas. But how well does this work? Can damage caused by past grazing be reversed, or will the removal of stock create new, unexpected communities? Continue reading

Can livestock grazing benefit biodiversity?

The endangered Plains Wanderer needs an open grassland habitat. Photo source: The Internet Bird Collection.

Grazing by livestock (mainly sheep and cattle) has irreversibly degraded many natural ecosystems in Australia. Consequently, stock are usually removed from public land when new conservation reserves are declared. The damaging effects of livestock on ecosystems such as rivers, wetlands and the alps are well known.

On the other hand, ecologists have recommended that stock continue to graze in certain types of reserves. Continue reading