How Are the Mammals Doing?

00:00:00: The general rule is that whenever we leave space for mammals, they come back.

00:00:05: Except there have been also a few drawbacks.

00:00:08: the common hamster For example...the name says everything but it's now critically endangered.

00:00:15: It ranges from Germany to China But within this range populations have almost completely disappeared.

00:00:26: Welcome to Inside Biodiversity.

00:00:29: This podcast is hosted by iDiv, the German Centre for Integrative Biodiversity Research.

00:00:34: My name is Volker Hahn and I am head of the Impact Unit at iDiv. And my guest today is Carlo Rondinini.

00:00:41: Carlo is a professor of zoology at Sapienza University of Rome.

00:00:45: His work focuses on global biodiversity assessment, mammal conservation, extinction risk analysis... ...and the effects of land use change in climate change on wildlife.

00:00:57: Carlo coordinates the Global Mammal Assessment.

00:01:00: He has contributed his expertise to IPBES and he serves on the IUCN Red List Committee.

00:01:06: Enjoy this conversation with Carlo Rondinini!

00:01:10: Let's talk about mammals, why do you study mammals?

00:01:14: What got you into choosing mammals as your main object of your studies?

00:01:20: So when I was a kid, uh...I actually like to listen to radio program on ethology by an Italian ethologist who's called Danilo Mainardi.

00:01:31: But that was all about bugs.

00:01:33: so but then-that were my interest in ecology started and then childhood and the life during my secondary school And Then When I decided to start a bachelor in biology, I met a very influential professor, Professor Luigi Boitani, who was one of the wonderful zoologists and conservation biologists.

00:01:59: And there...I really found what i wanted to work on especially on mammals and especially on conservation because conservation is something that they've found useful.

00:02:11: so that's why it brought me here.

00:02:15: Is there specific mammal species you like best?

00:02:19: Like a favorite.

00:02:23: So I have so many species that i like, like lemures and marsupials from Oceania but really the one they worked with found very intriguing although it is very common everyone knows in Europe.

00:02:40: its the European Hedgehog that I studied.

00:02:46: I like it because, uh... It is one of the few mammals that are completely non-territorial.

00:02:52: They're not aggressive to each other.

00:02:54: they have this very open mating system so its incredibly peaceful anymore Unfortunately apparently now declining Europe wide for slightly unknown reasons.

00:03:08: Okay yeah we'll talk about a few species today That both are declining as the hedgehog but also some that are increasing.

00:03:18: And the hedgehog lives in Europe and will start in Europe as well, there a couple of species have expanded over the last decades.

00:03:31: when we think about wolf or the lynx or beaver another carnivore has expanded its territory into Europe is golden jackal.

00:03:44: Can you tell us a little bit about what is happening here?

00:03:47: Why did for instance that Golden Jackal, why does it expand into Europe?

00:03:54: and Is this larger phenomenon?

00:03:56: or are the cases that I mentioned.

00:03:58: Are they exceptions Or are

00:04:02: there the rule?

00:04:03: So well, there is never a rule in conservation.

00:04:06: There's certainly no rule with mammals but... ...there are big trends in Europe and North America as well other parts of developed countries that the abandonment of agro-pastoralism means abandonment rural areas or mountain areas return of forests that are naturally returning in many places across Europe.

00:04:35: And with forest come the herbivores, wild boars and deers and then many other herbivors... come the carnivores.

00:04:46: So, the wolf has been first from Italy spread all across Europe but the jackal is.

00:04:51: it's the last amazing expansion of a large carnivore that we're witnessing was confined to the Balkans in the sixties basically and because of hunting and persecution an intensive use of the countryside now without with more and more people living in the countryside.

00:05:19: The jackal first reestablished a little bit from the Balkans, it's re-established in the eighties as small population that also came on the verge of Italy under very far east And then at some point the population has just exploded.

00:05:35: In last few years they have been expanding all their way to Finland North Spain West Italy South Even in Italy, we are camera trapping year after year and seeing more and more jackals coming.

00:05:50: So it's one indicator just one species but a process that is actually applying to so

00:05:58: many.

00:05:59: The jackal the golden jackal is a species that expanding into Europe?

00:06:06: And some others that I have mentioned or making a comeback.

00:06:10: Is there a bigger trend other mammal species expanding in Europe then decreasing?

00:06:20: Yeah, that is probably the case for Europe overall.

00:06:23: We have.

00:06:26: some of them are conservation successes like the Iberian Lynx and it was target of specific conservation actions reintroductions management off of rabbits that other than most important prey further for that species And others have been re-expanding in Europe for a variety of reasons, like beavers that are being reintroduced somehow officially.

00:06:56: Somehow unofficially and in different countries but certainly an expanding... We had authors expanding For example.

00:07:04: I know well the situation with the author in Italy.

00:07:07: It was almost exerpated when i was at university.

00:07:11: When finished my University it came back from a small population in southern Italy.

00:07:18: Probably because of the slightly different reason, but again linked to a reduction of pressures that was brought by European regulations on river quality and water-quality reductions of pollutants naturally re-expanded.

00:07:38: so let's say general rule is whenever we leave space for mammals, they come back.

00:07:45: Except that there have been also a few drawbacks.

00:07:49: I mentioned the European Hedrick but it's not the only one.

00:07:53: There are others The common hamster for example and their name says everything But is now critically endangered.

00:08:01: It ranges from Germany to China And within this range populations almost completely disappeared.

00:08:09: Yeah, its complex picture.

00:08:13: Some good news, at least in Europe.

00:08:15: Let's take a step back and look at the situation on the globe because obviously Europe is just small part of the globe.

00:08:25: if you had to describe this status off mammals On The Globe how would you describe it?

00:08:35: So we have one quarter Of the mammals globally that are at risk of extinction And the proportion increases slightly at every reassessment that we do.

00:08:47: So this is overall not a good situation at all and We have clear, very clear North-South or even better temperate to tropical trends Or differences in trends because populations tend to be stable temperate caused areas and still declining fast in tropical areas.

00:09:16: And this is basically, this means reforestation of real naturalization that we're witnessing in Europe and then North America and Canada et cetera.

00:09:27: improvements in China in nature.

00:09:30: but these are the expense or extraction resources from developing countries so we increasing our impacts on the tropics.

00:09:39: So that's why we see this nice picture locally, let's say if Europe is local.

00:09:46: But it's not an overall trend.

00:09:50: and

00:09:51: are the pressures different?

00:09:53: For Europe?

00:09:54: you said that its decreasing pressure from hunting, decreasing pressures for agriculture conservation successes.

00:10:03: what would be the drivers in the tropics?

00:10:06: Are they different or are just the same drivers but going the other direction.

00:10:12: The drivers are the same and most important driver remains conversion of forests, another natural land to agriculture to sustain an increasing human population as an increase per capita consumption.

00:10:31: So that remains the most important threat for most species.

00:10:35: For some of the mammoths and drivers are also related to over-exploitation, this is partly for food again like in bush meat in sub-Saharan Africa and Southeast Asia and other regions of the world And partly for more specific needs linked to trade like Chinese traditional medicine, still a lot of illegal trade off trophies and more direct threats.

00:11:07: Like this one?

00:11:10: The trends are more worrying in the tropics.

00:11:13: can we also make distinct distinctions between what type Animals are mostly threatened.

00:11:21: We hear a lot that it's the large mammals, uh... ...that are threatened more than small mammals or other broader categories.

00:11:30: what mammals are threaten more then others apart from tropics versus temperate regions

00:11:38: The picture is getting as always heterogeneous.

00:11:41: Large mammals, it is true are generally more threatened than small mammals and the reason is related to several factors so concurrent in the same direction.

00:11:52: The first one instead of course large mammals need more space and conserving species that need more spaces like for example African megafauna or even in Europe the brown bear for example is always more difficult.

00:12:09: The second one is that these species have life history traits, which make them particularly slow in recovering if populations are impacted by a threat.

00:12:21: So why for small mammals to think of small rodents?

00:12:24: For example it's very quick and fast to have a comeback after population reduction.

00:12:30: They reproduce several times per year, they start reproducing very young many young per female for the large mama cc opposite.

00:12:39: so this is a clear trend.

00:12:42: but then besides that there are also specific situations that impact relatively smaller species.

00:12:48: I think for example of all the lemurs in Madagascar Lemurs are impacted by deforestation in a place that has been already largely deforested In the nineteen fifties with forests remaining on the mountain ranges On the east coast of Madagascar, and these are still deforestered to the point at almost no forests left.

00:13:16: So this is declining fast.

00:13:19: Think of the pangolins.

00:13:21: There are eight species of pangolin, and they're all threatened with extinction in very high categories of risk because... ...of use their scales on Chinese medicine.

00:13:34: And now only recently China has taken measures to remove the scales from the official parmakopeia of China.

00:13:43: Hopefully this will have an impact.

00:13:46: Think about great apes.

00:13:49: All seven great apes, except us are either endangered or critically endangered.

00:13:55: They're large animals too but they are again threatened by direct persecution as for orangutans in Southeast Asia and by conversion of forests to plantations.

00:14:11: So yes we see trends But the situation is always region-dependent regionally different and different groups of species are threatened in different places.

00:14:25: Yeah, historically speaking many of the extinctions that have been documented among mammals were happened on islands.

00:14:33: is it the same reason?

00:14:35: That you know the area available Is limited on Islands as compared to the mainland is at The reason why we have so many or We had I don't know if we still have, but we used to have many extinctions on islands.

00:14:50: Yes that is certainly one of the most important reasons.

00:14:54: it's not the only one.

00:14:56: another important one is that in many cases species on islands were completely unprepared for humans and completely unprepared to them invasive species that are brought by human on ships like rats cats and other important invasives so they didn't evolve the capacity to respond, survive this new alien threat.

00:15:26: Another one is related And again, this brings more complexity to the picture.

00:15:35: Other reasons are related to the shape of the island, the heterogeneity or geography.

00:15:40: so there are islands that just flat and small can completely amenable for agriculture.

00:15:46: it is very easy to extirpate species from those islands There.

00:15:50: other islands that are volcanic with higher elevation ranges and mountain areas that aren't reachable.

00:15:57: So these islands do better.

00:15:59: The point is that we have seen many, many extinctions in the islands from... In the last say five hundred years.

00:16:07: But now we are starting to see the extensions on land.

00:16:10: Now that apparently my take.

00:16:14: of course there's no formal analysis of this but my take off these Is once we brought to extinction species at work easier to bring to extinction on islands.

00:16:26: We have started to expand our impact on land, the extent that... The land is an island.

00:16:32: at this point I mean with the impact of humans.

00:16:35: it's so pervasive.

00:16:37: even a large expanse of area acts as an Island in terms of response from other species and we are starting to witness the extinctions on land too.

00:16:49: I think it's remarkable that if you go back a few thousand years when there were very few humans on the planet, we already had quite a few extinction events driven by humans.

00:17:06: So even a small population really has this large impact on biodiversity and on mammal species If you take these more historic View on what's happening.

00:17:20: Where is the trend going?

00:17:22: Well, you already said it's more like shifting from the islands to the mainland but in terms of number of extinctions or the number of species threatened Is that increasing or decreasing?

00:17:36: Or do we even know

00:17:42: Two bits of evidence, one is a comparison between the historical extinctions since fifteen hundreds more or less and background rates of extinction from known periods outside of mass extinction events.

00:18:05: For mammoths, we have around two percent species extinct in the last five hundred years while based on the fossil records and rate of extinction in the fossil record.

00:18:15: The best estimate would be that it should expect zero point to so at least ten times higher than what one would expect from natural extinctions.

00:18:24: On the other bit of evidence is not from extinctions themselves but by changing risk of extinction and we have data for mammals, we've had data for the last thirty years more or less since nineteen ninety six to two thousand eight so a very short time period but let's say that every ten species that approach extinction there is one that gets farther from extinction than recovers.

00:18:53: And overall out of six thousand mammals there has been five hundred species who have approached extinction in these thirty years.

00:19:02: So they're not extinct yet.

00:19:04: Some of them may be very close, but that the they are sliding overall towards extinction.

00:19:09: so The number of mammal species that are threatened with extinction is increasing.

00:19:14: Is that what you're saying?

00:19:16: Yes

00:19:17: When you compare mammals to other species groups like birds fishes insects How how do they compare?

00:19:27: or they doing better worst?

00:19:29: So mamas are in this sense, probably close a little above the global average.

00:19:37: and these global averages is made of course off very different situations.

00:19:44: Birds have

00:19:46: always been... Sorry Carlo you mean above?

00:19:49: In the sense more threatened or less threatened?

00:19:52: More threatened.

00:19:53: Okay.

00:19:54: More threatened slightly more.

00:19:57: Birds are typically, overall less threatened with extinction than the other groups.

00:20:02: And I can only imagine possible reasons for this Certainly birds more mobile so they suffer less fragmentation of habitats.

00:20:13: barriers Can more easily find refuge Than then other species.

00:20:20: and because their more mobile They have much larger distributions about ten times larger than the average mammal.

00:20:30: So that means there might be part of the range where this species is less threatened and persists, And maybe there has also been more action earlier on birds being catalyzed.

00:20:43: if you think of Europe for example The European Birds Directive as in the first Nature-Legislation Conservation legislation in Europe and the Habitats Directive that includes mammals.

00:20:54: There are other groups that do a lot worse, amphibians.

00:20:57: The big crisis globally.

00:20:59: Forty-three percent of the amphibian species are at risk of extinction and there are more than one hundred species that are officially classified critically endangered possibly extinct because there hasn't been yet the proof or of the extinction.

00:21:15: but most of those pieces might be actually already extinct And this also depends on our right to reason.

00:21:22: so amphibia again in this case much smaller distribution, it is one-tenth of the distribution of a mammal.

00:21:29: They are linked to every specific habitat because they're linked to water for parts of their life cycle and unfortunately permeable skin.

00:21:39: that means that sensitive pollution more than others.

00:21:45: they have this ketridiomycosis that is wiping out populations for many of the species, so there are many problems that converge together in for these extinction crises.

00:22:03: For other groups we don't even know.

00:22:05: you mentioned fish.

00:22:07: We know something for the freshwater ones, because there are not so many species.

00:22:13: For marine species we have an idea of some of them.

00:22:17: but a lot is data deficiency in the seas as it's more complicated to collect information and for insects on land its even worse.

00:22:29: We have still huge taxonomic problems and we'll know very little of the distributions, let alone trends.

00:22:36: So it's difficult to... There are indications of large declines in some parts of the world but really it is hard for us to get a global picture like we do with vertebrates.

00:22:54: I recently came across numbers that I found quite astonishing that if you look at the biomass of mammals worldwide, The global share of wild mammals is only five percent.

00:23:09: Meaning that ninety-five percent Of global biomass Is humans and livestock And pets!

00:23:19: I also found another estimate That says Wild biomass is estimated to have declined since the rise of humans by eighty five percent.

00:23:28: So huge declines when we look at biomass.

00:23:32: and then

00:23:32: what I find interesting is that, We don't see it in species extinctions.

00:23:38: you mentioned that less than two percent of mammal species have been extirpated since fifteen hundred?

00:23:46: We already talked about there's a complex picture but having such different stories That You See When You Look At Different Metrics like biomass on the one hand, maybe population sizes and then species that I have become globally extinct less than two percent.

00:24:05: What does it tell us?

00:24:06: How do we make sense of

00:24:07: that?".

00:24:11: This is an important technical question.

00:24:15: We see the same for example in the seas And we know very well That many of these species will likely not go extinct at all in the near future but have been so depleted that fishermen don't go for those species anymore.

00:24:33: Usually, the shape of decline of species is not linear and it's a negative exponential.

00:24:41: So if the decline is at constant rate you expect big declines when population is bigger small declines never approaching extinction.

00:24:51: What brings extinction then?

00:24:55: a stochastic process, something that is actually completely random and happens in very small populations where whatever random external factor or environmental factors are some change in the loss of specific allele of genes.

00:25:22: Extinction may take a long time after the population has actually been depleted or as some say, even if I don't particularly like that term, afghan functionally extinct.

00:25:35: So we tend to have many functioning extinct species that might survive for centuries or even millennia just because of trends.

00:25:44: so We've talked a lot about Trends, trends for different areas in the world island species, mainland species transfer large and smaller mammals.

00:25:59: And also insects fishes etc.. We've touched a little bit on the different drivers if what we have mentioned so far is The pressure through hunting & poaching there's land use change So the agricultural pressure on habitat...we haven't talked much about climate yet, and certainly there are some other drivers as well.

00:26:29: You've mentioned invasive species especially on islands.

00:26:32: how would you rank the different drivers?

00:26:35: That is fairly easy because that's one of the information collected by the UCM Red List.

00:26:41: so we know from the red list that habitat loss definitely ranks first our exploitation ranks second.

00:26:49: then for now.

00:26:53: Then climate change is something that it's a bit complicated, for a variety of reasons.

00:26:59: the first reason deforestation for example.

00:27:09: to a declining population or overexploitation, it is not so easy to attribute changing climate.

00:27:17: that means change in many variables locally which don't necessarily all go the same direction and act over long time because its not an extreme event.

00:27:27: It's easier to attribute something to an extreme climatic event but if there are long-term changes then trigger long-term changes in populations and the interactions among populations.

00:27:40: So there is a lot of modelling on climate, but still a lot uncertainty.

00:27:47: I have to say that vast majority of models forecasts at current levels or speed of climate change it could become main threat for mammals in few decades.

00:28:04: But I still feel that the uncertainty is very large because we know little of actual response from each mammal population to change.

00:28:13: Some may be able just cope with a change, some maybe able to track climate.

00:28:20: others might go but I suspect at least for more time there are other immediate threats might wipe out populations before climate heats in.

00:28:37: So knowing about the drivers is important also for conservation to help mammals thrive?

00:28:44: What are the solutions, what other most efficient conservation tools that we have?

00:28:50: here?

00:28:50: I would divide the problem into.

00:28:52: one is the emergencies And we know reasonably well what are the best solutions for the emergencies.

00:28:59: from research that has been done on counterfactual analysis of sanctions prevented, and then conservation actions that are associated to those few improvements in conservation status as I was mentioning before.

00:29:16: Based upon this evidence it is pretty clear reintroductions and translocations are important just to escape extinction when numbers are very small, and also captive breeding associated with both reintroduction and trans location.

00:29:36: It seems that legislation can be associated many improvements things for example of the CITES,

00:29:43: the Convention on International Trade in Endangered Species regulates trade for many species and it does so effectively at least in many countries.

00:29:57: But this is all reactive conservation, investing a lot of money on one specific species can be good but still its single species.

00:30:10: So the big difference are indirect drivers.

00:30:14: The big societal changes are those that make a difference.

00:30:17: We've seen them in Europe if you like, a natural experiment because no one decided to leave the countryside.

00:30:23: Because we wanted to save the mammals but just people decided to move to the cities because there was work in the cities and working on the countryside wasn't economically viable anymore.

00:30:37: And this has brought a big change.

00:30:39: All of these scenarios that were used to forecast potential effects on mammals as well.

00:30:46: other species say that changes in how we produce food, how we consume food.

00:30:55: Changes in diets are those that would have the largest impact.

00:31:00: so what you need to do it will be leave more space for nature.

00:31:05: basically design a society that is capable of reducing overall impacts.

00:31:10: and some species still needs reactive conservation interventions but for many others, like the jackals.

00:31:20: Like the other large mammals that we've seen expanding in Europe but just leaving space would suffice.

00:31:28: That basically means that we need to produce more food for humans from less land.

00:31:35: Yeah!

00:31:37: The big challenge is feeding ten billion people and trying to preserve some nature somewhere And that means probably a mix of intensification over the culture in some places.

00:31:53: Maybe novel foods, maybe lab meat... Any solution?

00:32:00: I don't know any solutions and no expert on these solutions but I think technology could help us a lot.

00:32:09: Yeah i looked up numbers before our conversation.

00:32:13: Forty-five percent of the world's habitable land is agriculture.

00:32:20: Land used for agriculture, and eighty percent of that is used for livestock meat and dairy.

00:32:28: so really changing diets and changing agriculture could spare a lot of land for wilderness and for mammals to come back.

00:32:39: would you agree with

00:32:40: it?

00:32:41: Yes, our scenarios also say the same.

00:32:45: We made projections based on agricultural production for feeding these ten billion people in twenty fifty together with David Tilman and single most effective action is probably changing diet really and closing the yield gap, together with closing that is producing as much as possible where agriculture is carried out.

00:33:15: But changing diet would be a crucial element because it will require much less space.

00:33:21: I mean if we feed on agriculture rather than cattle.

00:33:25: Because of thermodynamics

00:33:28: The efficiency

00:33:29: of the diet is much higher.

00:33:31: The developed countries have made a lot progress grow a lot more food on an hectare.

00:33:38: But there are other regions in the world where agriculture is still very inefficient and then it uses a lot of land that could be spared for wildlife, especially with a growing population.

00:33:49: but that's maybe to different podcast episodes.

00:33:53: I think its important.

00:33:56: so may be last question already kind-of answered?

00:33:59: Its not the last one.

00:34:03: those people listening to this podcast, individuals what can they do today?

00:34:08: To help mammals thrive.

00:34:10: So well certainly diet is an important one.

00:34:14: less meat doesn't necessarily mean to become all vegetarian but just a bit less meat in the diet helps with all the wild mammals and then we have another well-meaning impact on the other species.

00:34:28: so we have to be very careful for example Domestic cats, keep domestic cats at home.

00:34:34: They are a big source of damage for wildlife.

00:34:39: they kill millions or billions small mammals every year.

00:34:44: Be careful with other pets.

00:34:46: that might be alien species and many invasive alien species have been introduced as pets.

00:34:53: Yeah, in general we need to think of living space and minimizing our actions for the rest of nature.

00:35:03: Great!

00:35:04: We've touched a lot very interesting topics during this conversation.

00:35:09: Carlo what would you like the audience remember from this conversation?

00:35:14: What is most important?

00:35:16: take home message your point.

00:35:19: Yeah, mamas are not just beautiful.

00:35:22: They're beautiful But they were also an important indicator of nature because some of them are very big.

00:35:30: and then conserving mammals means that we probably conserving many other species together with them And the important message is about space.

00:35:42: We need to leave space for the mammals.

00:35:45: Thank you very much Carlo for this very interesting conversation.

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