How much land is needed to help biodiversity?

As we enter the decisive decade for biodiversity, researchers are sharing their findings to help shape policy
20 June 2022

Interview with 

David Williams, University of Leeds, Angela Brennan, University of British Columbia & James Allan, University of Amsterdam


Decision making that will decisively influence the coming decade of biodiversity preservation efforts is on the horizon, and conservationists know it. The 2020 CBD (Convention of Biological Diversity) was placed on hold, like many other events, due to the coronavirus pandemic, so many in the field are awaiting the announcement of its go ahead later this year. As such there has been a recent glut of research published in scientific journals, made up of what you could call big picture global analyses. Scientists are aware their findings could make a real difference at the convention, and with previous targets not being met, such as the 2020 goal of protecting 17% of terrestrial areas which we fell short of by 2%, the very latest research is vital. Harry Lewis pulled together three of the biggest authors from this past week, David Williams, lecturer in Sustainability and the Environment at the University of Leeds, Angela Brennan, Conservation Scientist at the University of British Columbia and James Allan, researcher at the University of Amsterdam’s Institute for Biodiversity and Ecosystem Dynamics, to find out if the new speculated target of protecting 30% of land coverage by 2030 will be enough to safehouse species across the globe…

James - Our analysis shows that 44% of terrestrial area is an absolute minimum, but it doesn't necessarily have to be a protected area. And I think it's really important to make that nuance clear. When we think about how much lands at risk from conversion to human land uses the numbers become much more manageable. We're looking at an area about the size of South Africa spread across the world. You know, that's big, but it's not too big. And so we can target that. We don't need to think about half the planet, you know, 60% of the planet, et cetera...

Harry - Angela.

Angela - These numbers, they don't really address the fragmentation when habitat loss results in discrete patches of habitat and animals can move through non-habit habitat. But the data that we used in our analysis shows that movement declines with increasing pressures. So we really need to mitigate the factors that are limiting or preventing them from moving in those spaces. More than 75% of the land has been modified in some way by humans and more than 90% of the world's protected areas are embedded in that matrix of human dominated land.

Harry - And James, back to your 44% of land that requires some sort of protection. Did you look at the locations that required such protection?

James - Yeah, so we overlaid sort of maps of land use projections for 2030 and 2050 and saw where's at risk. Most of that's in Africa, sadly, which is my home continent, but that's very much the front line of the next decade. And we also tracked this under different development scenarios. So if we followed a more green trajectory in line with meeting Paris agreement 1.5 degree style targets, we actually could have sort of a sevenfold decrease there. So we've got a huge window of opportunity to do something good here. We just need to act quickly.

Harry - Yeah, David.

David - Sorry, just to comment on that as well. That's a fantastic point. So I think it it's really important that we don't just focus on this active protection if you like, putting fences up around things or managing the land in some way, but also think about kind of more passive protection. If we can stop the underlying drivers of habitat loss of deforestation, of all of these pressures, then our whole job just gets so much easier. So looking at the root causes of why we have problems is potentially even more important than actually the protection.

Harry - And again, what are those root causes?

David - James highlights, Africa, as where a lot of things are going to happen in the future. And that's really a combination of massive population growth and quite rapid increases in or projective increases in GDP. And those two things combined mean that we're gonna need to produce a lot more food with really low agricultural yields, very slowly increasing. So you need a big area to produce that food.

Harry - James.

James - Often the people living on the ground in the conservation areas around them are also losing their livelihoods, their land to these bigger, you know, forces of change such as commercial agriculture. And so conservation is a very clear win-win if you partner with them in the right way and empower local people like that.

Harry - All in all with negotiations coming up for the CBD this year, what is it that you want to see? Or what is it that you're hoping to see David?

David - The paper that I had out this week looks at whether the protected areas that we have, basically, whether they're big enough to support populations of target species of mammals in particular. And what we found is that about half of the world's mammals, we don't have big enough protected areas or well connected enough areas to actually support a population that's gonna survive in the long term. So from a protected area point of view, what I would like to see is trying to get a measure of actually keeping populations alive, not just setting land aside.

Harry - James, you got anything to add.

James - I think the targets themselves are shaping up very nicely. And whether you have a number like 25%, 30%, 40%, I don't think that matters. It's big and it's in the right direction. And one of the tragedies of the last 10 years of targets was governments sign this, and then no one does anything until they get near the deadline. And we just don't have time for that anymore. We can't sign an agreement, you know, this year and wait until five years down the track to act, it'll be too late. That's my biggest push.

Harry - Angela

Angela - From a connectivity perspective, I hope that the CBD can go big and take on the issue of connecting ecosystems and protected areas. Currently, I believe they're discussing some global connectivity indicators and there's a few that are on the table. And in our analysis we kind of put forth this indicator that describes how connected protected areas are from the perspective of moving mammals. And that's an aspect of connectivity that hasn't been captured before. In other global indicators.


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