Hunting responsible for mammal declines in half of intact tropical forests

MAY 14, 2019

by Public Library of Science

Defaunation—the loss of species or decline of animal populations—is reaching even the most remote and pristine tropical forests. Within the tropics, only 20% of the remaining area is considered intact, where no logging or deforestation has been detected by remote sensing. However, a new study publishing May 14 in the open-access journal PLOS Biology, led by Ana Benítez-López from Radboud University, the Netherlands, predicts that even under the seemingly undisturbed canopy, hunting is reducing populations of large mammals by 40% on average, largely due to increased human accessibility to these remote areas.

Overhunting, as opposed to deforestation, is undetectable by remote-sensing techniques, and to date, there were vast understudied areas in the tropics where hunting impacts on mammal communities were unknown. In this study, the authors have projected for the first time the spatial patterns of hunting-induced mammal defaunation in the tropics and have identified areas where hunting impacts on mammal communities are expected to be high.

Read on

Animal populations are shrinking due to their high-risk food-finding strategies

It hasn't been clear why certain animal populations are taking a hit, until now

Date:  November 15, 2018

Source:  Swansea University

A study using animal-attached technology to measure food consumption in four very different wild vertebrates has revealed that animals using a high-risk strategy to find rarer food are particularly susceptible to becoming extinct, as they fail to gather food for their young before they starve.

In the first study of its kind, a team of researchers led by Swansea University used thumbnail-sized electronic tags to record the movement of a number of individual condors, cheetahs, penguins and sheep in Argentina, South Africa and Northern Ireland over a six-year period.

Nicknamed the "Daily Diary," the tags record a mass of data -- everything from the animal's minute movements through space and time, to the temperature of its environment and light levels.

The results from the tags were used to measure:

The probability that each animal finds food items.

The size of the food items.

The effort used to find the food.

The effort used for all other activities such as rest, play etc.

Professor Rory Wilson of Swansea University, a world-leading expert on animal movement and lead author of the study, said: "We know that animal populations across the world are taking a hit, with the most charismatic animals like lions and cheetahs being among the worst affected, but up until now it hasn't been clear why.

Read on  

Declines in large wildlife lead to increases in disease risk

Date:

April 29, 2014

Source:

University of California - Santa Barbara

Summary:

In the Middle Ages, fleas carried by rats were responsible for spreading the Black Plague. Today in East Africa, they remain important vectors of plague and many other diseases, including Bartonellosis, a potentially dangerous human pathogen. The researchers concluded that the "spike in disease risk results from explosions in the number of rodents that benefit from the removal of the larger animals."

Continued