Wildlife in Yellowstone National Park is undergoing dramatic shifts with consequences that are beginning to return the landscape to conditions not seen in nearly a century, according to a series of new studies. In the park's northeast section, elk have decreased in number in their historic winter range in the Lamar Valley and are now more numerous outside the park. This change in elk numbers and distribution can be traced back to the reintroduction of wolves in 1995-96. Scientists have hypothesized that wolves affect both the numbers and the behavior of elk, thereby reducing the impact of browsing on vegetation, a concept known as a "trophic cascade."

Tropical forest restoration projects are exciting research sites for scientists studying factors that affect ecosystem recovery. Here, scientists are trying to understand plant community succession, i.e. the process of recovery after cleared lands are abandoned and allowed to regrow naturally. One of the most important components of this recovery process is seed dispersal, since seeds from nearby forests allow a deforested habitat to become populated again by native plants and trees.

Good news for aquatic life: the oceans just got a little bit safer. Okay, so most of the ocean remains vulnerable to human devastation, but on Thursday, President Barack Obama used his authority to create the most massive ocean reserve in the world. In a single day, the amount of the world’s ocean protected from commercial interests has effectively doubled. Originally, the Pacific Remote Islands Marine National Monument was something that George W. Bush established during his last weeks in office. However, Obama has taken the symbolic ocean protection and turned it into something useful by growing the area to six times its original size.

Herbivores, not herbicides, may be the most effective way to combat the spread of one of the most invasive plants now threatening East Coast salt marshes, a new Duke University-led study finds. Phragmites australis, or the common reed, is a rapid colonizer that has overrun many coastal wetlands from New England to the Southeast. A non-native perennial, it can form dense stands of grass up to 10 feet high that block valuable shoreline views of the water, kill off native grasses, and alter marsh function.

This week, dignitaries from U.S. Tribes and Canadian First Nations signed a treaty-the first among them in more than 150 years-to establish intertribal alliances for cooperation in the restoration of American buffalo (or bison) on Tribal/First Nations Reserves or co-managed lands within the U.S. and Canada. This historic signing of the "Northern Tribes Buffalo treaty" occurred in Blackfeet territory in Browning, Montana, and brought together members of the Blackfeet Nation, Blood Tribe, Siksika Nation, Piikani Nation, the Assiniboine and Gros Ventre Tribes of Fort Belknap Indian Reservation, the Assiniboine and Sioux Tribes of Fort Peck Indian Reservation, the Salish and Kootenai Tribes of the Confederated Salish and Kootenai Indian Reservation, and the Tsuu T’ina Nation.

Four whooping crane chicks raised in captivity began their integration into the wild Saturday as part of the continuing effort to increase the wild population of this endangered species. The cranes, hatched and raised by their parents at the U.S. Geological Survey's Patuxent Wildlife Research Center in Laurel, Maryland, were released on the U.S. Fish and Wildlife Service's Necedah National Wildlife Refuge in Wisconsin.

Rewarding landowners for converting farmland into forest will be key to sequestering carbon and providing wildlife habitat, according to a new study by Oregon State University and collaborators. Current land-use trends in the United States will significantly increase urban land development by mid-century, along with a greater than 10 percent reduction in habitat of nearly 50 at-risk species, including amphibians, large predators and birds, said David Lewis, co-author of the study and an environmental economist in OSU's College of Agricultural Sciences.

Interior Secretary Sally Jewell announced today the recovery of the Delmarva Peninsula fox squirrel, previously protected as an endangered species. The Interior Department made its finding based on an increase in distribution since 1967 from 4 to 10 counties where the squirrel can be found, and an overall population of 20,000. But despite these modest population gains, sea-level rise remains a severe threat to the species. "No one should discount the heroic conservation work that has been done to keep this squirrel from going extinct," said Brett Hartl, endangered species policy director at the Center for Biological Diversity. "But most of the places where the squirrel lives will eventually be underwater due to climate change and sea-level rise, and unfortunately most of the places on higher ground have already been lost to development."

Depictions of animals in ancient Egyptian artefacts have helped scientists assemble a detailed record of the large mammals that lived in the Nile Valley over the past 6,000 years. A new analysis of this record shows that species extinctions, probably caused by a drying climate and growing human population in the region, have made the ecosystem progressively less stable. The study, published in Proceedings of the National Academy of Sciences (PNAS), found that local extinctions of mammal species led to a steady decline in the stability of the animal communities in the Nile Valley.

Clownfish spend their entire lives nestling in the protective tentacles of host anemones, but new research shows that as babies they sometimes travel hundreds of kilometres across the open ocean. Although the process of long-distance dispersal by reef fish has been predicted, this is the first time that the high level exchange of offspring between distant populations has been observed. Dr Steve Simpson, Senior Lecturer in Marine Biology and Global Change in Biosciences at the University of Exeter, and colleagues from the Australian Research Council Centre of Excellence for Coral Reef Studies (ARC COE CRS), Sultan Qaboos University (Oman) and the Centre National de la Recherche Scientifique (France) have published their findings on the dispersal of Omani clownfish larvae in the journal PLOS ONE.