QUANTIFICATION OF THE WATER BUDGET AND NUTRIENT LOADING IN A SMALL PEATLAND1

ABSTRACT: Few water budgets exist for specific types of wetlands such as peatlands, even though such information provides the basis from which to investigate linkages between wetlands and upland ecosystems. In this study, we first determined the water budget and then estimated nutrient loading from an upland farm field into a 1.5 ha, kettle-block peatland. The wetland contains highly anisotropic peat and has no distinct, active layer of groundwater flow. We estimated the depth of the active layer using Fick's law of diffusion and quantified groundwater flow using a chemical mass balance model. Evapotranspiration was determined using MORECS, a semi-physical model based on the Penman-Monteith approach. Precipitation and surface outflow were measured using physical means. Groundwater provided the major inflow, 84 percent (44,418 m³) in 1993 and 88 percent (68,311 m³) in 1994. Surface outflow represented 54 percent (28,763 m³) of total outflows in 1993 and 48 percent (37,078 m³) in 1994. A comparison of several published water budgets for wetlands and lakes showed that error estimates for hydrologic components in this study are well within the range of error estimates calculated in other studies. Groundwater inflow estimates and nutrient concentrations of three springs were used to estimate agricultural nutrient loading to the site. During the study period, nutrient loading into the peatland via groundwater discharge averaged 24.74 kg K ha^-1, 1.83 kg total inorganic P ha^d, and 21.81 kg NO₃-N ha^-1.     

Movements,behavior, and habitat utilization of yellowfin tuna (<Emphasis Type="Italic">Thunnus albacares</Emphasis>) in the northeastern Pacific Ocean,ascertained through archival tag data

Sixty-eight yellowfin tuna, Thunnus albacares, (60-135 cm fork length) were caught and released with implanted archival tags offshore off Baja California, Mexico, during October 2002 and October 2003. Thirty-six fish (53%) were recaptured and the data were downloaded from all 36 recovered tags. Time at liberty ranged from 9 to 1,161 days, and the data were analyzed for the 20 fish that were at liberty for 154 or more days. The accuracy in the position estimates, derived from light-level longitude data and sea-surface temperatures (SSTs) based latitude, is about 0.41° in longitude and 0.82° in latitude, in this region. The movement paths, derived from position estimates, for the 20 yellowfin indicated that 19 (95%) remained within 1,445 km of their release locations. The estimated mean velocity along movement paths was 77 km/day. The southern and northern seasonal movement paths observed for yellowfin off Baja California are influenced by the seasonal movements of the 18°C SST isotherm. Cyclical movements to and from suitable spawning habitat (≥24°C SST) was observed only for mature fish. For the 12 fish that demonstrated site fidelity, the mean 95 and 50% utilization distributions were 258,730 km² and 41,260 km², respectively. Evaluations of the timed depth records resulted in discrimination of four distinct behaviors. When exhibiting type-1 diving behavior (78.1% of all days at liberty) the fish remained at depths less than 50 m at night and did not dive to depths greater than about 100 m during the day. Type-2 diving behavior (21.2% of all days at liberty) was characterized by ten or more dives in excess of 150 m during the day. Type-2 diving behavior is apparently a foraging strategy for fish targeting prey organisms of the deep-scattering layer during the day, following nighttime foraging within the mixed layer on the same prey. Yellowfin tuna exhibited occasional deep-diving behavior, and some dives exceeded 1,000 m, where ambient temperatures were less than 5°C. Surface-oriented behavior, defined as the time fish remained at depths less than 10 m for more than 10 min, were evaluated. The mean number and duration of surface-oriented events per day for all fish was 14.3 and 28.5 min, respectively. Habitat utilization of yellowfin, presented as monthly composite horizontal and vertical distributions, indicates confined geographical distributions, apparently resulting from an affinity to an area of high prey availability. The vertical distributions indicate greater daytime depths in relation to a seasonally deeper mixed layer and a greater proportion of daytime at shallower depths in relation to a seasonally shallower mixed layer.     

Construction and demolition waste management process modeling: a framework for the Brazilian context

Journal of Material Cycles and Waste Management - In Brazil, municipal public authorities are responsible for construction and demolition (C&amp;D) waste management. However, there is a lack of...     

Ancient behaviors of larval amphibians in response to an emerging fungal pathogen, <Emphasis Type="Italic">Batrachochytrium dendrobatidis</Emphasis>

Behaviors have evolved in response to various selection pressures over evolutionary time. However, not all behaviors are adaptive. Some presumably “ancient” behaviors, persistent for millions of years, may be detrimental in the face of novel selection pressures in modern times. These pressures include a multitude of emerging infectious diseases which may be stimulated by environmental changes. We examined how a globally emerging amphibian pathogen, Batrachochytrium dendrobatidis (BD), affected two key evolutionarily persistent behaviors displayed by amphibian larvae: aggregation and thermoregulation. Larval aggregation behavior is often essential for foraging, thermoregulation, and antipredator defense, but varies among species. Thermoregulatory behavior speeds larval development in ephemeral habitats. Specifically, we examined whether aggregation and thermoregulatory behaviors changed when exposed to the BD pathogen in two species (Bufo boreas and Rana cascadae) whose larvae aggregate in nature. In laboratory choice tests, larvae of neither species avoided infected conspecifics. BD-exposed B. boreas larvae aggregated, while unexposed R. cascadae larvae associated more frequently with BD-exposed conspecifics. There was no evidence of behavioral fever or altered thermoregulation in larvae of four species we examined (Pseudacris regilla, Rana aurora, B. boreas, R. cascadae). The absence of behavioral fever may suggest an inability of the larvae of some host species to mediate infection risk by this pathogen. Thermoregulatory behaviors may exhibit a high degree of evolutionary inertia in amphibian hosts because they are linked with host physiology and developmental rates, while altered aggregation behaviors could potentially elevate pathogen transmission rates, leading to increased infection risk in social amphibian species.     

A moral panic over cats

Some conservationists believe that free-ranging cats pose an enormous risk to biodiversity and public health and therefore should be eliminated from the landscape by any means necessary. They further claim that those who question the science or ethics behind their arguments are science deniers (merchants of doubt) seeking to mislead the public. As much as we share a commitment to conservation of biodiversity and wild nature, we believe these ideas are wrong and fuel an unwarranted moral panic over cats. Those who question the ecological or epidemiological status of cats are not science deniers, and it is a false analogy to compare them with corporate and right-wing special interests that perpetrate disinformation campaigns over issues, such as smoking and climate change. There are good conservation and public-health reasons and evidence to be skeptical that free-ranging cats constitute a disaster for biodiversity and human health in all circumstances. Further, there are significant and largely unaddressed ethical and policy issues (e.g., the ethics and efficacy of lethal management) relative to how people ought to value and coexist with cats and native wildlife. Society is better served by a collaborative approach to produce better scientific and ethical knowledge about free-ranging cats.     

Work-related deaths in Washington State, 1998-2002

INTRODUCTION: In Washington State, 87 workers are killed each year, on average, while in work status. To understand these incidents and to assist in focusing on and development of potential prevention measures, they must be well characterized. METHODS: Work-related fatalities between the years 1998 and 2002 are described by the demographics of the victims, types of incidents, the victims' occupations, and industries and location in which they worked. RESULTS: Motor vehicle- and machinery-related incidents accounted for nearly 33% and 14% of the incidents, respectively. Agriculture, forestry, fishing, hunting, and mining (n=87), and construction (n=83) had the most fatalities. Fatality rates per 100,000 workers for these industries were 25.7 and 8.7, respectively, compared to the state-wide average of 3.1 fatalities/100,000 workers. DISCUSSION: These data indicate numerous areas for prevention of work-related traumatic injuries and fatalities.     

Differences in olfactory species recognition in the females of two Australian songbird species

Although birds have recently been shown to possess olfactory abilities and to use chemical cues in communication, limited effort has been made to demonstrate the use of odorants in social contexts. Even less is known regarding the use of odorants in species recognition. The ability to recognize conspecifics should be more pronounced in social species. This study investigated the importance of olfactory cues in species recognition in females of two estrildid finch species with different levels of sociality. Combining odor preference tests with chemical analyses, we surveyed whether female zebra finches and diamond firetails are able to distinguish between the species based on volatile traits and whether individuals exhibit species-specific differences in body odorants. Zebra finches are more social than diamond firetails; nevertheless, both species have an overlapping distribution area. Applying an experimental Y-maze paradigm, we showed that zebra finches can use differences in their species odor fingerprints and displayed a significant preference for the odor of conspecifics over that of heterospecifics, whereas diamond firetails did not reveal a preference. Using gas chromatography and mass spectrometry, we demonstrated that body odorants of the two species were significantly different in relative composition. This finding demonstrates the potential importance of olfactory cues in species recognition, at least in social bird species. Even these two closely related species displayed remarkable differences in their responsiveness to similar chemical cues, which might be caused by species-specific differences in ecology, physiology, or evolution.