A test of multiple hypotheses for the function of call sharing in female budgerigars, Melopsittacus undulatus

In many social species group, members share acoustically similar calls. Functional hypotheses have been proposed for call sharing, but previous studies have been limited by an inability to distinguish among these hypotheses. We examined the function of vocal sharing in female budgerigars with a two-part experimental design that allowed us to distinguish between two functional hypotheses. The social association hypothesis proposes that shared calls help animals mediate affiliative and aggressive interactions, while the password hypothesis proposes that shared calls allow animals to distinguish group identity and exclude nonmembers. We also tested the labeling hypothesis, a mechanistic explanation which proposes that shared calls are used to address specific individuals within the sender–receiver relationship. We tested the social association hypothesis by creating four–member flocks of unfamiliar female budgerigars (Melopsittacus undulatus) and then monitoring the birds’ calls, social behaviors, and stress levels via fecal glucocorticoid metabolites. We tested the password hypothesis by moving immigrants into established social groups. To test the labeling hypothesis, we conducted additional recording sessions in which individuals were paired with different group members. The social association hypothesis was supported by the development of multiple shared call types in each cage and a correlation between the number of shared call types and the number of aggressive interactions between pairs of birds. We also found support for calls serving as a labeling mechanism using discriminant function analysis with a permutation procedure. Our results did not support the password hypothesis, as there was no difference in stress or directed behaviors between immigrant and control birds.     

A new approach to investigate the interactions between sediment transport and ecotoxicological processes during flood events

Purpose

The 'step-by step' principle was introduced into the European Union legislation on genetically modified organisms as a means to cope with uncertainty about environmental risks from the release of genetically modified organisms into the environment. The approval process is orientated along the stepwise reduction of containment which reflects a precautionary approach towards the risks of genetically modified organism release. Thus, the gradual reduction of containment should keep pace with the gradual generation of risk-related knowledge. This paper strives to clarify the meaning, legal status and practical importance of the principle. It also looks at whether non-European Union countries have adopted the principle as well, and how they practice it.

Methods

The article is based on research of the relevant legal texts, court cases and legal literature. In addition, a number of dossiers of applications for the European Union authorisation of release and placing on the market of genetically modified seed were analysed.

Results and conclusions

Although 'step-by-step' is not a precise legal rule it does have legal meaning as a principle guiding the risk assessment and management of genetically modified organism introduction into the environment. Assuming a process of gradual reduction of containment and scaling up of release ranging from closed systems via experimental release to cultivation the 'step-by-step principle' requires that the knowledge on environmental risks of genetically modified organisms should be generated on stages previous to the ones where the risk can result in damage. The analysis of the legislation of China, the United States of America and Brazil showed a differentiated approach towards the step-by-step principle.     

Effects of Liming on the Aquatic Fauna in a Norwegian Watershed: Why Do Crustaceans and Fish Respond Differently?

We studied the effects of liming on fish and crustaceans in a watershed which is in a region known to have one of the highest diversity of aquatic biota in Norway. This watershed, Enningdal, is shared between Norway (1/3) and Sweden (2/3) and includes 61 lakes  >  1.0 ha in Norway. Liming started on a large scale in the 1980s. Currently, a total of 26 of lakes (43%) are limed, covering 93% of the total lake area. The mean value ± S.D. of pH and the concentration of inorganic labile Al in these lakes is 6.62 ± 0.35 and 3 ± 4 μg l⁻¹, respectively. Historical data of fish communities have been obtained from surveys, while test-fishing and sampling of crustaceans were conducted in 24 lakes in recent years (2002–2004). The present study shows that crustaceans to a greater extent than fish has responded to improved water quality after more than 20 years of liming. Of a total of 120 fish populations, 42 (35%) have gone extinct. Only five of the lost fish populations (12%) have been re-established, all due to human re-introductions. Physical barriers are considered to be the main factor preventing fish from invading limed lakes. In contrast, crustaceans have been re-established in most limed lakes. This may be mainly due to their good spreading capacity. However, they might also have survived in refuges within the watershed, or as resting-eggs in the sediment.     

Demographic Analyses of a Hunted Black Bear Population with Access to a Refuge

Studying one of two bear species not experiencing widespread population decline, provides insight into the population responses of the six bear species that are in decline and into responses of other long-lived species for which data are difficult to collect. Black bear ( Ursus americanus ) sanctuaries were established in North Carolina (U.S.) in 1971 to protect core populations of bears and to provide dispersing bears for hunting. Population index values, derived from counts of bears visiting bait stations, were significantly greater inside the Pisgah Bear Sanctuary than outside and were greater along trails than along roads. Survivorship of bears outfitted with transmitter collars was greater for sanctuary bears alone than for sanctuary plus non-sanctuary bears. Monte Carlo analyses of Leslie matrices showed that the bear population in the sanctuary would be stable if cub survivorship, p ₀, was about O.7, and the population in the sanctuary plus the surrounding area would be stable if p ₀ was about 0.83. Estimates of litter survivorship in North Carolina indicate, however, that p ₀ can not exceed O.71. Overall, the matrix analyses indicated an ultimate population decline in the total bear population (sanctuary plus surrounding area). The population index of the bait station did not show a discernible decline. The Pisgah Bear Sanctuary provides dispersing bears for hunters and provides some protection for the resident bears. The sanctuary may not, however, provide resident bears with enough protection to maintain a viable breeding population within its boundaries. Reducing human access to bears and their habitat appears crucial, either by making large sanctuaries or by eliminating roads.     

Misdefining “climate change”: consequences for science and action

The restricted definition of “climate change” used by the Framework Convention on Climate Change (FCCC) has profoundly affected the science, politics, and policy processes associated with the international response to the climate issue. Specifically, the FCCC definition has contributed to the gridlock and ineffectiveness of the global response to the challenge of climate change. This paper argues that the consequences of misdefining “climate change” create a bias against adaptation policies and set the stage for the politicization of climate science. The paper discusses options for bringing science, policy and politics in line with a more appropriate definition of climate change such as the more comprehensive perspective used by the Intergovernmental Panel on Climate Change.     

The effects of climate change on landscape diversity: an example in Ontario forests

The predicted increase in climate warming will have profound impacts on forest ecosystems and landscapes in Canada because of increased temperature, and altered disturbance regimes. Climate change is predicted to be variable within Canada, and to cause considerable weather variability among years. Under a 2 × CO₂ scenario, fire weather index (FWI) is predicted to rise over much of Ontario by 1.5 to 2 times. FWI may actually fall slightly, compared to current values, in central eastern Ontario (Abitibi), but for central-south Ontario it is expected to rise sharply by as much as 5 times current values. We predict that the combination of temperature rise and greater than average fire occurrence will result in a shrinkage of area covered by boreal forest towards the north and east; that some form of Great Lakes forest type will occupy most of central Ontario following the 5 C isotherm north; that pyrophilic species will become most common, especially jack pine and aspen; that patch sizes will initially decrease then expand resulting in considerable homogenization of forest landscapes; that there will be little 'old-growth' forest; and that landscape disequilibrium will be enhanced. If climate change occurs as rapidly as is predicted, then some species particularly those with heavy seeds may not be able to respond to the rapid changes and local extinctions are expected. Anthropogenically-altered species compositions in current forests, coupled with fire suppression over the past 50 years, may lead to forest landscapes that are different then were seen in the Holocene period, as described by paleoecological reconstructions. In particular, forests dominated by white pine in the south and black spruce in the middle north may not be common. Wildlife species that respond at the landscape level, i.e., those with body sizes >1 kg, will be most affected by changes in landscape structure. In particular we expect moose and caribou populations to decline significantly, while white-tailed deer will likely become abundant across Ontario and Quebec.     

Extent of H-atom abstraction from OH + p-cymene and upper limits to the formation of cresols from OH + m-xylene and OH + p-cymene

Aromatic hydrocarbons are important constituents of vehicle exhaust and of non-methane volatile organic compounds in ambient air in urban areas. It has recently been proposed that dealkylation is a significant pathway for the OH radical-initiated reactions, leading to the formation of phenolic compounds and/or oxepins (Noda, J., Volkamer, R., Molina, M.J., 2009. Dealkylation of alkylbenzenes: a significant pathway in the toluene, o-, m-, and p-xylene + OH reaction. Journal of Physical Chemistry A 113, 9658–9666.). We have investigated the formation of cresols from the reactions of OH radicals with m-xylene and p-cymene, and obtain upper limits of <1% for formation of each cresol isomer from OH + m-xylene and <2% for formation of each cresol isomer from OH + p-cymene. In addition, we have measured the formation yield of 4-methylacetophenone (the major product formed subsequent to H-atom abstraction from the CH(CH₃)₂ group) in the OH + p-cymene reaction to be 14.8 ± 3.2%, and estimate that H-atom abstraction from the CH₃ and CH(CH₃)₂ groups in p-cymene accounts for 20 ± 4% of the overall OH radical reaction. We also used a relative rate technique to measure the rate constant for the reaction of OH radicals with 4-methylacetophenone to be (4.50 ± 0.43) × 10^?12 cm³ molecule^?1 s^?1 at 297 ± 2 K.     

Influence of fur trade,famine, and forest fires on moose and woodland caribou populations in northwestern Ontario from 1786 to 1911

Hudson’s Bay Company records were used to estimate the 1786–1911 annual number of moose (Alces alces andersonii) and caribou (Rangifer tarandus caribou) involved in trade by northern Ojibwa natives to the company post at Osnaburgh House (51°10′N 90°15′W) in northwest Ontario, Canada. The human population for the early 19th century, and the number and severity of human starvations from 1786 to 1911 were estimated. The extent of forest fires in the region around Osnaburgh was documented using a “fire-day” index computed from Hudson’s Bay Company journals and using qualitative archival information. It is argued that the human population was too small to have caused the observed early 19th century moose and caribou population decline solely through predation. Likewise, severe early 19th century famines were caused by climatic factors rather than by declines in moose and caribou numbers. Habitat change caused by increased forest fires correlates with the observed decline of caribou, while moose increased and subsequently collapsed as winter shelter was destroyed. A burgeoning human population, sustained during winter food shortages on potatoes donated by the Hudson’s Bay Company, then kept ungulate populations to low levels until the late 19th century. Only then did maturing forests and a new outbreak of fires provide renewed habitat for resurgences of, respectively, caribou and moose.