Tapir populations threatened by slow reproductive rates and fragmented habitats

Tapir populations threatened by slow reproductive rates and fragmented habitats



In Brazil, calling someone a tapir is considered a derogatory term. However, there are several reasons why it should be seen as a praise.

Tapirus terrestris, South America’s largest native land mammal and one of the planet’s most efficient supporters of biodiversity, is one of the most important, underappreciated, and persecuted species.

The tapir, like the elephant, is an intelligent animal with a high concentration of neurons, contrary to popular belief in Brazil. It was once persecuted to the point of being classified a vulnerable species in the Atlantic Forest.

The tapir has gained its reputation as the “gardener of the forest” after being discovered to be a crucial player in sustaining plant diversity by disseminating important seeds over broad distances in a study conducted by So Paulo State University (UNESP).

However, in order to ensure its own survival, the Brazilian tapir of the Atlantic Forest requires immediate intervention to combat the difficulties associated with population fragmentation. A vast road network runs through their habitat, making it difficult for tapirs to move between forest sections and frequently resulting in the animals being injured and killed by vehicles.

These are the findings from a recent study carried out by Kevin Flesher, a researcher at the Center for Biodiversity Studies at the Michelin Ecological Reserve in Brazil’s Bahia state, and Patrícia Medici, co-founder of the Ecological Research Institute (IPÊ) and one of the world’s leading tapir specialists. The study assessed tapir distribution and conservation status in the Atlantic Forest, which spans parts of Brazil, Argentina and Paraguay.

Published in the journal Neotropical Biology and Conservation, the study shows that even though tapirs are restricted to 1.78% of their original habitat in the Atlantic Forest, it seems that most populations are stable or showing signs of growth.

Patrícia Medici photographing a newly released tapir. Image by João Marcos Rosa/IPÊ.
Patrícia Medici photographing a newly released tapir. Image by João Marcos Rosa/IPÊ.

“Tapirs persist in tiny areas with small, disconnected populations that are far from being in a secure state of conservation,” Medici says. “The truth is that the situation is better than in the past, when tapirs were extinguished in many parts of the Atlantic Forest. The population has remained stable over the last few decades, but if we don’t take careful action, the situation will get worse.”

Medici chairs the tapir specialist group at the IUCN, the global conservation authority. The group comprises 130 members in 27 countries, and focuses on the four known tapir species: the South American or lowland tapir (Tapirus terrestris), the mountain tapir (T. pinchaque), found in the Andes; the Central American tapir (T. bairdii); and the Malayan tapir (T. indicus), found in Southeast Asia. The latter three are considered endangered on the IUCN Red List, while the lowland tapir is listed as vulnerable.

Few viable populations remaining

Already wiped out along the lower slopes of the coastal range in southern Rio de Janeiro state and in parts of the Brazilian northeast by the late 19th century, the lowland tapir was confined to the Atlantic Forest, where it faced a critical period from the 1950s to the 1970s. Hunting during this time slashed the remaining population, and isolated small groups of tapirs into ever more fragmented patches of forests.

Current research shows there are at least 48 populations peppered across 26,654 square kilometers (10,291 square miles) of the Atlantic Forest — just a fraction of the biome’s original expanse of 1.5 million km2 (579,000 mi2). The estimated number of tapirs in the biome ranges from 2,665 to 15,992, with the largest group (numbering between 1,000 and 6,000 individuals) found in the forests that straddle Iguaçu National Park in Brazil’s Paraná state and the province of Misiones in Argentina.

This map shows the current distribution of the 48 known populations of lowland tapirs in the Atlantic Forest. Image courtesy of Flesher et al. (2022).
This map shows the current distribution of the 48 known populations of lowland tapirs in the Atlantic Forest. Image courtesy of Flesher et al. (2022).

But this population group is an outlier; most of the other groups are much smaller, some numbering only around six animals. This is the case in the Mata Escura Biological Reserve in the state of Minas Gerais, where the local population is nearing extinction.

In fact, of the 48 tapir populations studied, only three to 14 groups are considered viable in the long term, both from a demographic point of view — that is, if there are enough individuals to survive when faced with existing threats in the region — and a genetic one. Genetically, the risk is that individuals from the same family interbreed, degrading genetic diversity and raising the risk of disorders caused by recessive genes.

This population viability analysis, used to estimate the number of animals in a given location, and whether this number is enough to survive over a 100-year period, paints a worrying picture for the tapir.

“The population viability analysis is what tells us if an animal will merely persist in a place or if it belongs to a population that should still exist 100 years [from now],” Medici says. “The magic number is to have between 200 and 250 tapirs [per population group]. This is the necessary amount for stabilizing a healthy population considering normal impacts and for maintaining their genetic viability.”

The lowland tapir (Tapirus terrestris) is the largest native land mammal in South America. Image by João Marcos Rosa/IPÊ.
The lowland tapir (Tapirus terrestris) is the largest native land mammal in South America. Image by João Marcos Rosa/IPÊ.

Flesher says small populations are at high risk when they have to cross roads to find enough food to eat. The tapir’s reproductive cycle also poses a risk factor. Females typically get pregnant only once in three years. The pregnancy lasts 14 months and produces just one calf. This leaves populations susceptible to rapid decline, especially if the number of animals in a given area is small. The loss of a single individual can mean local extinction.

Medici says there’s an urgent need to adopt measures to guarantee the safety of animals moving from one patch of forest to another. Many end up as roadkill when trying to cross busy highways like the BR-101, which cuts through the Brazilian section of the Atlantic Forest from north to south.

“I have no qualms or doubts in saying that the greatest threat to tapirs in our country today is from cars on the highway,” Medici says. “The road network will only expand and the problem will increase with it. Our strategy is to prepare mitigation plans such as underpasses, fences, signs and radars at the critical places where many tapirs are known to die from crossing the highway. We have very efficient tools. What we don’t have is the political drive to pressure the concessionaires running these highways to do what needs to be done.”

Despite the prevailing risks, Medici and Flesher say they still harbor some optimism about the situation of the tapir in the Atlantic Forest, especially the larger populations and in areas where agriculture and livestock farming have declined.

“From what we have seen in the field, there is less hunting going on, especially in the southern and southeastern mountains,” Flesher says. “Land colonized there many years ago is being abandoned, so forests are able to grow back and the tapirs occupy these areas.”

He adds that in São Paulo state’s Serra do Mar State Park, home to one of the largest tapir populations in Brazil, “the animals are starting to descend the mountains almost far enough to enter the city of Caraguatatuba.”

Citation:

Flesher, K. M., & Medici, E. P. (2022). The distribution and conservation status of Tapirus terrestris in the South American Atlantic Forest. Neotropical Biology and Conservation, 17(1), 1-19. doi:10.3897/neotropical.17.e71867

This article by Luís Patriani was first published by Mongabay.com on 9 March 2022 | Translated by Maya Johnson. Lead Image by João Marcos Rosa/IPÊ.


What you can do

Support ‘Fighting for Wildlife’ by donating as little as $1 – It only takes a minute. Thank you.


payment

Fighting for Wildlife supports approved wildlife conservation organizations, which spend at least 80 percent of the money they raise on actual fieldwork, rather than administration and fundraising. When making a donation you can designate for which type of initiative it should be used – wildlife, oceans, forests or climate.

close
Vanished - Megascops Choliba by Jose Garcia Allievi

Discover hidden wildlife with our FREE newsletters

We don’t spam! Read our privacy policy for more info.

Supertrooper

Founder and Executive Editor

Share this post with your friends




Facebook Comments

Leave a Reply

guest
2 Comments