Prehistoric or historic? What is the best baseline for #rewilding in the Neotropics? @JCSvenning and @FaurbySoren investigate the previous distribution of megafauna to inform future options of trophic rewilding in today’s #rewildingscience thread
Trophic rewilding – use of species to promote trophic cascades and self-regulating ecosystems often involves discussion around megafauna (large bodied species). Their high mobility, resitance to top-down effects, and ability to disperse nutrients makes them ecologically valuable
It is these species that have been subject to anthropogenic declines, including in the Neotropics. Historic baselines for species richness and distribution are now so intermingled with human effects that they may not represent a feasible point to base introductions on…
Despite this, the authors write, forward-looking rewilding agendas should be historically informed, using knowledge of regional species over long timescales to understand environmental conditions at which they are adapted to
This can take the form of Pleistocene rewilding (looking beyond historic baselines i.e. 5000-50,000 ya). Why? Whilst 5000-10,000y is a decent amount of time, biota adaptations will have occurred over much longer timescales, with faunal states developing across millions of years
This paper looks into the two baselines that can be used in the Neotropics. This part of the world has seen strong pre-historic late-quaternary losses including; ground sloths, giant armadillos, horses, and varied carnivores…
To research the suitability of the baselines, data from historically extinct (post-1500 AD) and extirpated extant megafauna, as well as extinct megafauna from the late Pleistocene-Holocene are used to map out rewilding potential and species richness
3 body size groups for herbivores were used in this analysis; meso- (10-99kg), macro- (100-999kg) and mega-herbivores (>1000kg). Carnivores are similarly categorised, with overall megafauna separated out into 3 diversities; current, historic baseline, and pre-historic baseline
The results suggest high potential for trophic rewilding across all of the Neotropics, particularly throughout the pre-historic baseline estimates. Extinct or extirpated species with large potential ranges include proboscideans, horses, camelids, large deer, and large canids...
The potential for rewilding varied across biomes, with the highest values being found for tropical and sub-tropical grasslands, savannahs, and shrublands under the prehistoric baseline. Potential was found to also be high for various tropical and subtropical biomes
Importantly, the estimated present-natural distributions show reduced diversities of meso-,macro-, and megacarnivores and herbivores relative to both prehistoric and historic baselines. No megaherbivores are left today in the region meaning missing ecosystem-engineer effects
There is therefore potential for use of trophic rewilding using recently extirpated species e.g. re-faunation of ‘empty’ forests. For prehistoric baselines, the biome of tropical/subtropical grasslands, savannas and shrublands have particularly high rewilding potential (>30 sp)…
Use of a prehistoric baseline may also provide greater functions due to higher group diversity. Within the megaherbivores, >20 sp are recorded from the region, compared to 10 extant sp globally. Including smaller herbivores, variability in effects on ecosystem structure increases
In terms of reintroductions, many small to moderately sized extant vertebrate species can be considered in restoration projects as relatively unproblematic options. This can be largely-based on a historic baseline due to widespread defaunation across the region…
However, data suggests that even a pre-defaunation historical baseline is still an unusually megafauna-poor state. There’s a strong argument for end-Pleistocene/early Holocene baseline as a starting point for restoration, as it was under these conditions that biodiversity evolved
They conclude by acknowledging that rewilding is dependent on biological and societal possibilities/constraints. Trophic rewilding must be compatible with society. Landscape circumstances will also effect how rewilding can be implemented; the amount of land available being key
Generally, reintroductions toward a historic baseline are more simple, using extant and often nearby species. However, they argue, it is worth considering if prehistoric losses could be partially overcome using taxon substitutions to reinstate lost processes
We unfortunately couldn’t cover everything in this paper, so please follow the link to have a read and a good look at the figures! We’d love to hear your thoughts and get a discussion going.

Full paper:…

• • •

Missing some Tweet in this thread? You can try to force a refresh

Keep Current with Rewilding Science

Rewilding Science Profile picture

Stay in touch and get notified when new unrolls are available from this author!

Read all threads

This Thread may be Removed Anytime!


Twitter may remove this content at anytime! Save it as PDF for later use!

Try unrolling a thread yourself!

how to unroll video
  1. Follow @ThreadReaderApp to mention us!

  2. From a Twitter thread mention us with a keyword "unroll"
@threadreaderapp unroll

Practice here first or read more on our help page!

More from @RewildingS

5 Apr
1/ Are you interested in how to carry out a reintroduction based #rewilding project? Then this paper (& thread) is for you. Zamboni et al introduce the reintroductions of giant anteater, collared peccaries, tapirs and more to The Iberá Rewilding Program IRP (Argentina) Image
2/ The Iberá rewilding project is part of the 13,000km2 Iberá Reserve; made up of public & private land. It has marshes, lagoons, small rivers, temporarily flooded grasslands, savannas, and forests. The Conservation Land Trust bought 1500km2 of private land in 1999 to restore. Image
3/ The project uses this definition of #rewilding “species reintroduction to restore ecosystem functioning” from…
Read 17 tweets
3 Dec 20
Kicking off the afternoon session of the #RewildingSymposium is @JCSvenning talking about 'restoring the role of megafauna in European ecosystems'
He begins by highlighting that current megafauna is unusually poor. Last at this level >30 million years ago. Historically, super diverse megafauna was the norm.
He points out that most current species are 100,000 to >1m years old. Meaning they have a complex evolutionary background with the landscape and complex ecological characteristics
Read 31 tweets
3 Dec 20
Today we're virtually at the @RewildingEurope #RewildingSymposium and will be bringing you updates throughout the day on the latest science from european landscapes #rewilding
Paul Jepson of ecosulis the first speaker of the day, stating that #rewilding presents a new narrative in conservation fit for the 21st century. There are many actors shaping it, but in particlar its an opportunity for young people to shape and define their future environment
He says the science behind current laws in particular Natura2000 are based on science which is 50 years out of date. We need to redesign laws across Europe based on a new narrative and incorporating modern scientific thinking on rewilding
Read 22 tweets
8 Nov 20
1/ This week we end with the future directions of conservation paper by Jozef Keulartz (2016). #rewilding has varied forms, which rather than competing, can be complementary. Read this #rewildingscience thread and join in the discussion
2/ Which historical baseline is used as a reference state is one of the central debates in #rewilding. This can depend on cultural and ecological context of where rewilding takes place….
3/ It has been argued that historic baselines are irrelevant due to current anthropogenic drivers e.g. climate change making it difficult to recreate historical ecosystems. There are two thoughts; to abandon history entirely, or to move the baseline to a more distant past
Read 23 tweets
10 Oct 20
1/ An exploration into the role of megafauna, ecosystem functioning and #rewilding is the topic of #rewildingscience today. Can we learn from the Pleistocene to influence today’s world for the better?
2/ As discussed in previous threads, megafauna have been in a state of decline and extinction since the late Pleistocene. Such large animals would surely have an impact on the environment so what are the consequences of their declines on ecosystem function?
3/ Understanding not only why they went extinct but how their loss effects ecosystem functioning is important for many reasons. Arguably the most pressing of which is how their legacy has an impact on the functioning of the current biosphere
Read 21 tweets
8 Oct 20
1/ #Rewildingscience with rewilding as a new framework in management by P. Jepson (2016)

-People can experience ‘ecological boredom’ and show indifference to wildlife issues⬇️

-Rewilding embraces change around current management and reinvigorates 21st century #conservation⬆️
2/ Since ~2008 the number of rewilding articles has shown a sharp incline, highlighting the growing interest in this ‘radical’ form of ecological management. This challenges existing conservation frameworks…
3/ Conservation frames are shaped by scientific technologies, media, management practices and legislative practices. This dictates how we manage the environment. Rewilding could be introduced as a new frame, opening up debate on how nature ‘management’ should be approached
Read 7 tweets

Did Thread Reader help you today?

Support us! We are indie developers!

This site is made by just two indie developers on a laptop doing marketing, support and development! Read more about the story.

Become a Premium Member ($3/month or $30/year) and get exclusive features!

Become Premium

Too expensive? Make a small donation by buying us coffee ($5) or help with server cost ($10)

Donate via Paypal Become our Patreon

Thank you for your support!

Follow Us on Twitter!