Nature Bytes

Nature Bytes

Size of forest matters for lemurs

The occurrence probability of some of the lemur species in a tropical dry forest increases with fragment size but can increase or decrease with fragment isolation depending on the species, according to a study published in PLOS ONE. Lemurs live only in Madagascar, and nearly all species are at risk of extinction primarily due to habitat loss and fragmentation. The effects of forest loss and of forest fragmentation are not well understood, however. To assess their impact, researchers from University of Toronto surveyed lemurs in fragmented dry deciduous forest in Ankarafantsika National Park, Madagascar between June and November 2011, observing six lemur species in 42 forest fragments. They then used incidence function models to examine whether the lemurs formed metapopulations, spatially-separated populations within a species, in a fragmented landscape. In their simulations, the researchers found that three of the lemur species did form metapopulations in forest fragments. Within these metapopulations, occurrence was affected by forest fragment size and isolation. However, fragment size appeared to be more important in determining lemur occurrence, with larger forest patches being associated with increased lemur occurrence. Madagascar forests are becoming increasingly fragmented, and this work helps clarify how lemurs respond.

India’s rivers contaminated by metals

According to a recent report published by the Central Water Commission, 42 rivers in India are polluted with at least two toxic heavy metals. Ganga, the national river, is polluted with five heavy metals — chromium, copper, nickel, lead and iron. Contaminants are finding their way to the rivers and are adversely affecting their health. Lack of monitoring and enforcement also makes it difficult for countries and regions to understand and deal with this challenge. Metal contamination in the environment is one of the persistent global environmental problems. This contamination is caused by continuous growth of industries like mining, tannery, and electroplating. Unlike organic contaminants, heavy metals are nonbiodegradable and also carcinogenic. Heavy metals such as zinc, copper, nickel, mercury and arsenic tend to accumulate in organisms, which may lead to a reduction in species diversity. The present report attempts to provide the water quality scenario of Indian rivers.

Plastic Paradise

The invention of synthetic plastic created an era of disposable products. Watertight and endlessly malleable, plastic is the perfect invention yet, its miraculous durability is also its curse because it never goes away. The documentary, Plastic Paradise, takes a look at some of the damages that it does on the environment. Plastic Paradise begins with a disturbing image of a dead bird being cut open, as plastic objects are removed from its stomach. This leads to a brief history of plastic. Anyone who has visited a beach has encountered plastic residue, but viewers may not realise the extent of the problem. The centrepiece of the film is a journey that Angela Sun, the director, takes to the Midway Atoll, USA. The large island in the Pacific has become a massive garbage dump that Sun’s camera explores. The enormous amount of waste has proved deadly to the large population of albatrosses that are one of the island’s primary residents. To watch the documentary, visit