Certain G.,Norwegian Institute for Nature Research |
Certain G.,Norwegian Institute of Marine Research |
Skarpaas O.,Norwegian Institute for Nature Research |
Bjerke J.-W.,Norwegian Institute for Nature Research |
And 17 more authors.
PLoS ONE | Year: 2011
The magnitude and urgency of the biodiversity crisis is widely recognized within scientific and political organizations. However, a lack of integrated measures for biodiversity has greatly constrained the national and international response to the biodiversity crisis. Thus, integrated biodiversity indexes will greatly facilitate information transfer from science toward other areas of human society. The Nature Index framework samples scientific information on biodiversity from a variety of sources, synthesizes this information, and then transmits it in a simplified form to environmental managers, policymakers, and the public. The Nature Index optimizes information use by incorporating expert judgment, monitoring-based estimates, and model-based estimates. The index relies on a network of scientific experts, each of whom is responsible for one or more biodiversity indicators. The resulting set of indicators is supposed to represent the best available knowledge on the state of biodiversity and ecosystems in any given area. The value of each indicator is scaled relative to a reference state, i.e., a predicted value assessed by each expert for a hypothetical undisturbed or sustainably managed ecosystem. Scaled indicator values can be aggregated or disaggregated over different axes representing spatiotemporal dimensions or thematic groups. A range of scaling models can be applied to allow for different ways of interpreting the reference states, e.g., optimal situations or minimum sustainable levels. Statistical testing for differences in space or time can be implemented using Monte-Carlo simulations. This study presents the Nature Index framework and details its implementation in Norway. The results suggest that the framework is a functional, efficient, and pragmatic approach for gathering and synthesizing scientific knowledge on the state of biodiversity in any marine or terrestrial ecosystem and has general applicability worldwide. © 2011 Certain et al.
Martin J.,University of Lyon |
Martin J.,Norwegian University of Life Sciences |
Martin J.,University of Witwatersrand |
Martin J.,University Claude Bernard Lyon 1 |
And 9 more authors.
Journal of Animal Ecology | Year: 2013
Movement is fundamental to individual and population dynamics, as it allows individuals to meet their basic requirements. Although movement patterns reflect interactions between internal and external factors, only few studies have examined the effects of these factors on movement simultaneously, and they generally focused on particular biological contexts (e.g. dispersal, foraging). However, the relative importance of these factors in driving individual routine movements might reflect a species' potential flexibility to cope with landscape changes and therefore buffer their potential impact on fitness. We used data from GPS collars on Scandinavian brown bears to investigate the relative role of these factors, as well as an additional factor (period of the year) on routine movements at two spatial scales (hourly and daily relocations). As expected, internal factors played a major role in driving movement, compared to external factors at both scales, but its relative importance was greater at a finer scale. In particular, the interaction between reproductive status and period of the year was one of the most influential variables, females being constrained by the movement capacity of their cubs in the first periods of the year. The effect of human disturbance on movement was also greater for females with cubs than for lone females. This study showed how reciprocal modulation of internal and external factors is shaping space use of brown bears. We stress that these factors should be studied simultaneously to avoid the risk of obtaining context-dependent inferences. Moreover, the study of their relative contribution is also highly relevant in the context of multiple-use landscapes, as human activities generally affect the landscape more than they affect the internal states of an individual. Species or individuals with important internal constraints should be less responsive to changes in their environment as they have less freedom from internal constraints and should thus be more sensitive to human alteration of the landscape, as shown for females with cubs in this study. © 2012 The Authors. Journal of Animal Ecology © 2012 British Ecological Society.
News Article | April 7, 2016
Since the early 2000s when Research Associate Shawn Padgett pioneered the use of video cameras on nests to read bands, the Center for Conservation Biology (CCB) and other groups have used camera traps to identify breeding adult peregrine falcons.
The first phase of Operation Woodpecker went off without a hitch, but it's too early to call it a success. Bryan Watts explained that the point of the exercise is to establish a breeding population of red-cockaded woodpeckers within the Great Dismal Swamp National Wildlife Refuge. It would be the second population of the endangered birds in Virginia. A closely watched group of the birds have been doing well in the Piney Grove preserve in Sussex County. Watts is the director of the Center for Conservation Biology. The CCB collaborated in the operation with the U.S. Fish and Wildlife Service, The Nature Conservancy, Virginia Department of Game and Inland Fisheries, North Carolina Department of Transportation and J. Carter and Associates. Biologists captured four male and four female birds from healthy populations in the Carolina Sandhills National Wildlife Refuge in South Carolina and in the Palmetto-Peartree Preserve in North Carolina. The collaborators identified individual birds for the translocation, selecting birds that had hatched this year and therefore would disperse this fall. The birds were caught in the evening of Oct. 22, just after they entered their nesting cavity for the night. Birds were captured using telescopic net poles that cover the cavity entrance. The boxed woodpeckers were driven to their new home in the Great Dismal, where 32 artificial cavities had been installed in trees there. Each bird was placed in a new home, and the cavity opening was covered with a screen. "At dawn, we pulled the screens off, and let the birds disperse," Watts said. The relocation technique for these birds is not new. The CCB used essentially the same process in the early 2000s to boost the woodpecker population in the Piney Grove habitat. "It worked really well," Watts said. "The retention rates have been similar to the natural retention rates—birds that have hatched in that population have stayed at a similar rate to ones that we brought in." CCB biologist Mike Wilson noted that the relocated woodpeckers joined an existing population at Piney Grove and had no trouble mingling with the resident birds. "That translocation to Piney Grove was really important," Wilson said. "Twenty-five birds were moved up; five of those birds became breeders." Watts explained that before their habitat was lost to clearing and logging, red cockaded woodpeckers were fairly plentiful—but probably not common—south of the James. Virginia is at the northern fringe of the species' range, and until the relocation, Piney Grove had Virginia's only breeding population of red-cockaded woodpeckers. The birds are doing quite well in their Sussex County home, Watts said. "But they are all in one place," he added. "That makes them vulnerable to catastrophic impacts like a hurricane, which could flatten Piney Grove. And that would be that." The translocation was a major undertaking, with a slate of logistics that wouldn't be unfamiliar to Seal Team Six. Watts explained that the red cockaded woodpecker is a species that needs a number of special conditions to thrive. In the first place, he said, the birds are cavity nesters and quite selective about the trees they choose. "This species requires live pine, and older-age live pine," he said. When it comes to nest, they have a preference for a mature pine that's 80 years old or more. Watts explained that the woodpeckers are the only bird in North America that excavates cavities in live pine trees. "It's a very unusual strategy," he said. "The birds choose trees that are infected with red heart disease, which softens the heartwood of the tree." It takes a red-cockaded woodpecker months to hammer out a home, Watts explained, so the group prepared the Great Dismal site for woodpeckers by constructing artificial cavity boxes that were fitted into the trunks of appropriate trees. A total of 32 cavities were prepared for the eight birds. Watts said that the cavities were separated into eight separate neighborhoods, or "recruitment clusters," to accommodate woodpecker lifestyle preferences. "When these birds are released, they may settle within that cluster or they may leave altogether or they may mix up," he explained. "So we don't know who is going to like whom and what areas they're going to like." Good red-cockaded woodpecker habitat also has a clear understory; the brushy undergrowth is usually kept to a minimum by fire, Watts explained. Piney Grove is kept in top shape by regular controlled burns, but he said the peaty soil of the Great Dismal precludes such a management technique for the relocated population. "Once you get a peat fire going, it's almost impossible to put out," Watts said. "So they're going to have to keep the understory clear by other means." The birds also have a complex social structure and are one of the few North American bird species that are cooperative breeders: Young birds often help to raise the new chicks. "This behavior evolves in species with very restricted habitat," Watts explained." When the young reach a certain age, there's often no place to go, because the habitat is bottled up." He noted other birds with similar parenting behavior include brown-headed nuthatch, purple gallinule and the Harris hawk. Wilson said that when it comes to forage, the red cockaded woodpeckers are known as "ant specialists," especially when young. They move up to wood roaches as adults. In winter, when the bugs are scarce, the birds get by on pine nuts. Their eating habits also affect habitat preferences, he said. "Each group, or cluster, generally requires anywhere from a quarter- to a half-mile radius foraging zone," Wilson said. "Definitely a larger area than a red bellied or a red headed woodpecker." Watts explained that the establishment of a second population of Virginia's red-cockaded woodpeckers has been a goal of several conservation groups for a decade. But, he said, the yardstick of the success of Operation Woodpecker will be in the reproduction. "It's a milestone," Watts said. "But we need to keep in mind the distinction between introducing birds, like we did last week, versus birds establishing a population, which we won't know until we see breeding in the spring."
Ellstrand N.C.,Center for Conservation Biology |
Kaus A.,Institute for Mexico |
Lubinsky P.,U.S. Department of Agriculture |
McDade L.A.,Claremont Graduate University |
And 6 more authors.
BioScience | Year: 2010
Hybridization in the wild between closely related species is not unusual. In some cases, hybridization may prove beneficial for a rare taxon. Under certain conditions, however, a rare taxon can be driven rapidly to extinction by hybridizing with a more common taxon. This problem is urgent because human activities are increasingly bringing together cross-compatible species that were previously geographically isolated. US conservation policy has yet to address how to deal with hybrid-derived individuals whose ancestry includes an endangered species. Developing sound science-based conservation policy that addresses hybridization requires cross-disciplinary social-science and life-science research to address the following two questions: (1) How do human decisions with regard to species protection, trade, transportation, land use, and other factors affect the opportunities for, and rates of hybridization between, rare species and more common relatives? and (2) How do the positive or negative perceived values regarding hybrids and hybrid-derived individuals compare with values regarding their nonhybridized counterparts from social, cultural, economic, and environmental perspectives? In this article we explore the ways to inform such policy using a multidisciplinary approach. © 2010 by American Institute of Biological Sciences. All rights reserved.