Monitoring ecological change: a view from the streets

Imagine 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.

You’d also be keen to know how the demography, or age distribution, of plants changed. How abundant were seedlings and saplings back in 2013? Did recruitment become more, or less, common over time? At the other extreme, how many big old plants were there in 2013, especially old trees that provide hollows for birds and animals? Did hollow-bearing trees decline or increase over the 50 year period?

What chance do we have to collect such a dataset for the denizens of 2063?

It’d be awesome to have a network of continuous transects from one end of the continent to the other. Especially if the transects contained information on individual trees and shrubs, including how big each plant was. This dataset would let future ecologists answer questions like: how quickly did exotic species migrate across the countryside? How localized were the original seed trees?  Which routes were most and least important for migration and invasion?

It’d be even better if this dataset was freely available for everyone to use: planners, practitioners, researchers, farmers, community groups and students. And I don’t want to sound greedy, but it would be cool if it extended across the entire world, so future citizens can compare changes across latitudes and continents.

Does this sound like a fairy tale? A romantic whim? A dreamer’s lament? Well, guess what? We’ve already got it! 

Well, not quite, but we do have a huge, free dataset that we can use for many of these purposes. It’s called Google Street View.

Sitting in my study on a wet winter evening, I’ve just returned from a virtual road trip around south-east Australia. Along the way, I took these holiday snaps. Actually, Google took all the photos – a continuous stream of them, along every main road in every continent of the world. I just cut, pasted, manipulated the colors and added the captions. If I air-brushed out Google’s road markers, would you have known that I hadn’t left my room?

As the photos show, Street View can be used to assess tree cover and vegetation structure along virtually every roadside in the world. If you know the flora, you can identify the dominant trees and shrubs, and sometimes even the ground plants. In many cases, the number of young and old plants can be counted, as in the snapshots of the regenerating Saw Banksias and the old, hollow-bearing Grey Box.

For conspicuous species, like the young, red-leaved exotic, we can detect not just big stands, but lone, young plants: the first invaders that may seed future migrations and invasions. We can’t do any of that from an air photo, a satellite image, or by collecting widely scattered quadrats on the ground. Fortunately we all have free access to this extraordinary network of continuous, high-quality, geo-referenced images of vegetation and land use patterns across the globe. What we do with it is limited, not by the technology, nor the cost, but by our imagination.

From snapshot to global chronology?

The satellite images in Google Earth let everyone investigate recent ecological changes, by comparing patterns between recent Landsat images. These comparisons will become increasingly useful as the duration between the oldest and most recent satellite images extends. By contrast, the current implementation of Google Street View lets users see the most recent images, not older ones. But imagine how valuable this dataset will be in the future, if we can compare Street View images across time.

It might be fun in 2063 to find out when the old house down the street was last painted. But it’d be much more interesting to find out how quickly species migrated across continents, and how ecosystems changed over time.

Street View is an amazing resource that we can all use to document and better understand changes in vegetation patterns across local, regional, continental and indeed, global scales.

So go to it, head off on your own, cross-continental, ecological road trip. The traffic, and the vegetation, will probably be a lot worse in another 50 years time.

Acknowledgements

Thanks to Dale Nimmo and Peter Neaum for sparking my interest in the endless ecological possibilities of Google Street View. All of the images in this post were taken from Google Street View before being manipulated.

Observations from The Big Wet

Many readers sent in detailed observations describing how their local vegetation changed after the 2000s drought, in response to my last blog, What did you get from the Big Wet? If you haven’t read all the comments, please do, as they contain a fascinating array of outcomes. Please add some more observations, especially if the comments remind you of other changes in your area. I’ll synthesize the many responses in a future blog. Thanks again to everyone who submitted their observations, I’m most grateful.