Broad-scale Surveys Research Articles

Potential Use of Radiometric Data for Wildlife Habitat Modelling

The potential use of existing radiometric data sets, previously collected for prospecting purposes, has very rarely been used as a variable predictor in wildlife habitat modelling. The utility of radiometric data for predicting vegetation community patterns and wildlife habitat was investigated in the Australian arid zone using the Burt Plain bioregion as a case study. Using spatial datasets and a Species Distribution Modelling Toolkit, arid zone vertebrate species were modelled with Generalised Linear Modelling (GLM) regression modelling techniques. These models were used to predict the probability of occurrence of a species at any given location, defined in terms of its environmental attributes. A statistical correlation between the radioactive elements uranium, thorium and potassium, and terrain aspect was found. No statistical correlations were established between the radioactive elements and vegetation patterns; although we suspect these exist at finer scales of mapping. Radiometric data were identified as explanatory variables in the habitat models of all of the 32 vertebrate species examined, and used as illustration in the development of probabilistic spatial predictions of three species (Red Kangaroo, Macropus rufus; Lesser Hairy-footed Dunnart, Sminthopsis youngsoni; and Rabbit, Oryctolagus cuniculus) in the bioregion. Our analyses suggest that radiometric data sets involving the radioactive elements: (uranium, thorium, and potassium), and vegetation could be used as predictors of biodiversity patterns at the bioregional and landscape level. This is an important finding given the challenges posed in undertaking broad-scale biological surveys in the arid zone of Australia.

Amphibian declines: promising directions in understanding the role of disease

The decline of amphibian populations worldwide is a recognized phenomenon. A variety of important causes have been linked to the declines but perhaps the most renowned cause, in terms of popular press exposure, funding dispersal and papers published, is disease. In particular, chytridiomycosis, a disease caused by the amphibian chytrid fungus Batrachochytrium dendrobatidis (Bd), is a lethal emerging infectious disease that has had profound effects in some amphibian species, but occurs without catastrophic effects in others (Fisher, Garner & Walker, 2009b). Bd affects species differentially. In many cases it is the major threat to animals already stressed by other critical challenges, such as habitat destruction, pollution, invasive species and climate change. In addition to its impact on amphibian populations, the spread and presence of Bd is likely to impact human activities via effects on the pet, bait and food trade (Schloegel et al., 2009, 2010).

Hybridization and introgression across different ploidy levels in the Neotropical orchidsEpidendrum fulgensandE. puniceoluteum(Orchidaceae)

The hypothesis of gene flow between species with large differences in chromosome numbers has rarely been tested in the wild, mainly because species of different ploidy are commonly assumed to be reproductively isolated from each other because of instantaneous and strong postzygotic barriers. In this study, a broad-scale survey of molecular variation was carried out between two orchid species with different ploidy levels: Epidendrum fulgens (2n = 2x = 24 chromosomes) and Epidendrum puniceoluteum (2n = 4x = 52 chromosomes). To test the strength of their reproductive barriers, we investigated the distribution of genetic variation in sympatric and allopatric populations of these two species and conducted crossing experiments. Nuclear and plastid microsatellite loci were used to genotype 463 individuals from eight populations across the geographical range of both species along the Brazilian coastal plain. All six sympatric populations analysed presented hybrid zones, indicating that hybridization between E. fulgens and E. puniceoluteum is a common phenomenon. Bayesian assignment analysis detected the presence of F(1) and F(2) individuals and also signs of introgression, demonstrating a high potential for interspecific gene flow. Introgression occurs preferentially from E. fulgens to E. puniceoluteum. Pure parental individuals of both species display strong genotype-habitat associations, indicating that environment-dependent selection could be acting in all hybrid zones. This study suggests that hybridization and introgression are evolutionary processes playing a role in the diversification of Epidendrum and indicates the importance of investigations of hybrid zones in understanding reproductive barriers and speciation processes in Neotropical orchid species.

Use of Habitats as Surrogates of Biodiversity for Efficient Coral Reef Conservation Planning in Pacific Ocean Islands

Marine protected areas (MPAs) have been highlighted as a means toward effective conservation of coral reefs. New strategies are required to more effectively select MPA locations and increase the pace of their implementation. Many criteria exist to design MPA networks, but generally, it is recommended that networks conserve a diversity of species selected for, among other attributes, their representativeness, rarity, or endemicity. Because knowledge of species' spatial distribution remains scarce, efficient surrogates are urgently needed. We used five different levels of habitat maps and six spatial scales of analysis to identify under which circumstances habitat data used to design MPA networks for Wallis Island provided better representation of species than random choice alone. Protected-area site selections were derived from a rarity-complementarity algorithm. Habitat surrogacy was tested for commercial fish species, all fish species, commercially harvested invertebrates, corals, and algae species. Efficiency of habitat surrogacy varied by species group, type of habitat map, and spatial scale of analysis. Maps with the highest habitat thematic complexity provided better surrogates than simpler maps and were more robust to changes in spatial scales. Surrogates were most efficient for commercial fishes, corals, and algae but not for commercial invertebrates. Conversely, other measurements of species-habitat associations, such as richness congruence and composition similarities provided weak results. We provide, in part, a habitat-mapping methodology for designation of MPAs for Pacific Ocean islands that are characterized by habitat zonations similar to Wallis. Given the increasing availability and affordability of space-borne imagery to map habitats, our approach could appreciably facilitate and improve current approaches to coral reef conservation and enhance MPA implementation.

Disruption of an exotic mutualism can improve management of an invasive plant: varroa mite, honeybees and biological control of Scotch broomCytisus scopariusin New Zealand

Summary 1. A seed-feeding biocontrol agent Bruchidius villosus was released in New Zealand (NZ) to control the invasive European shrub, broom Cytisus scoparius, in 1988 but it was subsequently considered unable to destroy sufficient seed to suppress broom populations. We hypothesized that an invasive mite Varroa destructor, which has caused honeybee decline in NZ, may cause pollinator limitation, so that the additional impact of B. villosus might now reach thresholds for population suppression. 2. We performed manipulative pollination treatments and broad-scale surveys of pollination, seed rain and seed destruction by B. villosus to investigate how pollinator limitation and biocontrol interact throughout the NZ range of broom. 3. The effect of reduced pollination in combination with seed-destruction was explored using a population model parameterized for NZ populations. 4. Broom seed rain ranged from 59 to 21 416 seeds m )2 from 2004 to 2008, and was closely correlated with visitation frequency of honeybees and bumblebees. Infestation of broom seeds by B. villosus is expected to eventually reach 73% (the average rate observed at the localities adjacent to early release sites). 5. The model demonstrated that 73% seed destruction, combined with an absence of honeybee pollination, could cause broom extinction at many sites and, where broom persists, reduce the intensity of treatment required to control broom by conventional means. 6. Nevertheless, seed rain was predicted to be sufficient to maintain broom invasions over many sites in NZ, even in the presence of the varroa mite and B. villosus, largely due to the continued presence of commercial beehives that are treated for varroa mite infestation. 7. Synthesis and applications. Reduced pollination through absence of honeybees can reduce broom seed set to levels at which biocontrol can be more effective. To capitalize on the impact of the varroa mite on feral honeybees, improved management of commercial beehives (for example, withdrawal of licences for beekeepers to locate hives on Department of Conservation land) could be used as part of a successful integrated broom management programme at many sites in NZ.

Spatial and temporal associations between recovering populations of common ravenCorvus coraxand British upland wader populations

1. Recovering populations of predators and scavengers have often given rise to concerns about the impact they may have on prey species. Particularly, this is the case when the prey species are of economic or conservation importance. 2. Recovery of common raven Corvus corax populations in the UK and Europe has given rise to a conflict with some stakeholders over their concerns for both the protection of livestock and the possible detrimental impact on some upland bird species, particularly ground nesting waders. This has led to demands by some land managers for licences to lethally control ravens to protect upland breeding birds. 3. We used data from broad scale surveys of distribution and abundance of upland breeding birds in the UK carried out in 1980–1993 and 2000–2002 to test whether variation in raven abundance or change in raven abundance was negatively associated with changes in abundance of five species of waders. 4. We found no significant negative spatial or temporal relationships between ravens and any of the five species of waders. However, weak (0·05 < P < 0·1) negative relationships between raven abundance and trends of curlew Numenius arquata and lapwing Vanellus vanellus may warrant further investigation. 5. Synthesis and applications. Our study found no significant negative associations between raven abundance and population changes in upland waders, and so does not provide support to justify granting of licences for the lethal control of ravens in the interest of population-level conservation of these upland wader species. However, the near significant negative associations with lapwing and curlew merit further investigation. This study emphasizes the importance of making a thorough evaluation of the evidence base before making decisions regarding predator control.

The biology and ecology of the ocean sunfish Mola mola: a review of current knowledge and future research perspectives

Relatively little is known about the biology and ecology of the world’s largest (heaviest) bony fish, the ocean sunfish Mola mola, despite its worldwide occurrence in temperate and tropical seas. Studies are now emerging that require many common perceptions about sunfish behaviour and ecology to be re-examined. Indeed, the long-held view that ocean sunfish are an inactive, passively drifting species seems to be entirely misplaced. Technological advances in marine telemetry are revealing distinct behavioural patterns and protracted seasonal movements. Extensive forays by ocean sunfish into the deep ocean have been documented and broad-scale surveys, together with molecular and laboratory based techniques, are addressing the connectivity and trophic role of these animals. These emerging molecular and movement studies suggest that local distinct populations may be prone to depletion through bycatch in commercial fisheries. Rising interest in ocean sunfish, highlighted by the increase in recent publications, warrants a thorough review of the biology and ecology of this species. Here we review the taxonomy, morphology, geography, diet, locomotion, vision, movements, foraging ecology, reproduction and species interactions of M. mola. We present a summary of current conservation issues and suggest methods for addressing fundamental gaps in our knowledge.

What limits the distribution and abundance of the native conifer Callitris glaucophylla (Cupressaceae) in the West MacDonnell Ranges, central Australia?

The conifer Callitris glaucophylla J.Thompson &amp; L.A.S.Johnson (Cupressaceae) is a fire-sensitive obligate seeder with a heavily fragmented distribution across the Australian continent. We undertook a broad-scale biophysical survey and analysed the population structure of 21 populations in the West MacDonnell Ranges of central Australia. C. glaucophylla had a patchy distribution associated with steep, rocky metamorphic areas with limited evidence of fire. Variation in population structures was clearly related to recent fire history. Nearly half of ‘adult’ C. glaucophylla trees (&gt;5-cm stem diameter) from the sampled stands were dead, with the proportion at individual sites related to evidence of fire. Fire scars were evident on 48% of all live trees we measured. The overall density of live adult trees conformed to a negative exponential size-class distribution, consistent with a regionally stable population structure. However, we found higher sapling densities and lower seedlings densities than expected by this distribution. This regional peak in the sapling size class reflects a pulse of recruitment, possibly associated with a wet period in the 1970s. Low seedling densities are probably due to subsequent drought. We conclude that fire controls the distribution of Callitris on the West MacDonnell Ranges, and the timing of recruitment depends on rainfall patterns.

A comparison of the effectiveness of camera trapping and live trapping for sampling terrestrial small-mammal communities

Context. There is an increasing reliance on the use of camera-trap technologies for surveys of medium to large terrestrial mammals. Camera trapping may, however, also have significant applications for broad-scale surveys of small mammals. Aims. The present study aims to compare results from camera-trapping surveys to those of the more traditional live-trapping techniques. Specifically, it aims to test the effectiveness of the techniques for detecting species, and the cost effectiveness of both approaches. Methods. Surveys were conducted across 36 sites in the Grampians National Park, Victoria, Australia, between April and July 2009. At each site, independent surveys were conducted for small mammals by using a combination of Elliot and cage trapping, then camera trapping. Results for the two different approaches were compared for both their ability to generate small-mammal presence data and their cost effectiveness. Key results. Camera-trapping surveys of 36 sites in the Grampians National Park compared favourably with those of live-trapping surveys. Similar species were detected across the sites, and camera trapping was a considerably more cost effective than live trapping. Conclusions. Camera-trapping surveys of small terrestrial mammals may provide a new and cost-effective technique for surveying terrestrial small mammals. This is particularly the case when presence data are the main requirement of the survey, with no requirement to capture and tag animals. Implications. Given the cost-effective nature of camera trapping, there is potential to use this approach to increase the level of replication and spatial coverage of small-mammal surveys. Improving the replication and spatial coverage of studies has the potential to significantly increase the scope of research questions that can be asked, thus providing the potential to improve wildlife management.

Oyster and Macroalgae Bioindicators Detect Elevated δ15N in Maryland’s Coastal Bays

Nitrogen loading from anthropogenic sources, including fertilizer, manure, and sewage effluents, has been linked with declining water quality in coastal lagoons worldwide. Freshwater inputs to mid-Atlantic coastal lagoons of the USA are from terrestrially influenced sources: groundwater and overland flow via streams and agricultural ditches, with occasional precipitation events. Stable nitrogen isotopes ratios (δ15N) in bioindicator species combined with conventional water quality monitoring were used to assess nitrogen sources and provide insights into their origins. Water quality data revealed that nutrients derived from terrestrial sources increased after precipitation events. Tissues from two bioindicator species, a macroalgae (Gracilaria sp.) and the eastern oyster (Crassostrea virginica) were analyzed for δ15N to determine spatial and temporal patterns of nitrogen sources. A broad-scale survey assessment of deployed macroalgae (June 2004) detected regions of elevated δ15N. Macroalgal δ15N (7.33 ± 1.15‰ in May 2006 and 6.76 ± 1.15‰ in July 2006) responded quickly to sustained June 2006 nutrient pulse, but did not detect spatial patterns at the fine scale. Oyster δ15N (8.51 ± 0.89‰) responded slowly over longer time periods and exhibited a slight gradient at the finer spatial scale. Overall, elevated δ15N values in macroalgae and oysters were used to infer that human and animal wastes were important nitrogen sources in some areas of Maryland’s coastal bays. Different nitrogen integration periods across multiple organisms may be used to indicate nitrogen sources at various spatial and temporal scales, which will help focus nutrient management.

Using marine mammal habitat modelling to identify priority conservation zones within a marine protected area

One common approach to marine conservation is the designation of marine protected areas (MPAs). Marine mammals have been proposed as a target species for such areas due to their role as indicators of ecosystem processes. In NE Scotland, a large multiple-use MPA has been desig- nated to protect bottlenose dolphins Tursiops truncatus. We used broad-scale surveys throughout this MPA to model habitat preferences of different marine mammals. We aimed to investigate the degree of overlap between distributions of different species, the environmental factors influencing their dis- tributions, and the effect of spatial scale on the significance of different environmental predictors. Bottlenose dolphins had a primarily coastal distribution with localised areas of intense use, in contrast to harbour porpoises Phocoena phocoena, harbour seals Phoca vitulina and grey seals Halichoerus grypus, which were widely dispersed throughout the MPA. At larger scales (4 × 4 km grid cells), seal distribution was significantly related to depth, seabed slope, distance to shore and mean sea surface salinity, whereas at the smallest scale (1 × 1 km grid cells), sediment type was also important. This study demonstrated the hierarchical pattern of distributions, with areas of high relative density occur- ring within a broader protected area that the animals were known to regularly frequent. Habitat pref- erence models therefore provide a valuable tool for determining which areas should be given high- est conservation priority and for identifying key locations for further research on interactions between these species and anthropogenic stressors.

Invasive forest pest surveillance: survey development and reliability

Worldwide, a large number of potential pest species are introduced to locations outside their native ranges; under the best possible prevention scheme, some are likely to establish one or more localized populations. A comprehensive early detection and rapid-response protocol calls for surveillance to determine if a pest has invaded additional locations outside its original area of introduction. In this manuscript, we adapt and spatially extend a two-stage sampling technique to determine the required sample size to substantiate freedom from an invasive pest with a known level of certainty. The technique, derived from methods for sampling livestock herds for disease presence, accounts for the fact that pest activity may be low at a coarse spatial scale (i.e., among forested landscapes) but high at a fine scale (i.e., within a given forested landscape). We illustrate the utility of the approach by generating a national-scale survey based on a risk map for a hypothetical forest pest species threatening the United States. These techniques provide a repeatable, cost-effective, practical framework for developing broad-scale surveys to substantiate freedom from non-native invasive forest pests with known statistical power.

Distribution and multi-annual abundance trends of the copepod Temora longicornis in the US Northeast Shelf Ecosystem

The average spatial distribution and annual abundance cycle are described for the copepod Temora longicornis from samples collected on broadscale surveys (1977-2006) and along continuous plankton recorder transects (1961-2006) of the US Northeast continental shelf ecosystem. After its annual low in winter, T. longicornis abundance begins to increase in coastal waters with the northern progression of spring conditions. Annual maximum shelf concentrations were found in the more southern inshore waters of the region during the summer months. Abundance throughout most of the ecosystem increased sharply in the early 1990s and remained high through 2001. During this period, the copepod became more numerous and widespread in offshore shelf waters. Abundance declined to approximately average levels in 2002 for the remainder of the time series, but its extended offshore range remained intact. Correlation analysis found that the copepods interannual abundance variability had a significant negative relationship with surface salinity anomalies throughout the ecosystem, with higher correlations found in the northernmost subareas. Temora longicornis abundance in the ecosystem's southernmost subarea (Middle Atlantic Bight) did not increase in the 1990s and was found to be negatively correlated to surface temperature, indicating that continued global warming could adversely impact the copepods annual abundance cycle in this region.

What Makes Industrial Sites Heritage Significant and How Can they be Managed to Retain Their Heritage Value in an Operating System? The Heritage of Hydro Tasmania–a Case Study

Over three years, I have undertaken a comprehensive heritage survey of all aspects of the Hydro Tasmanian system, including one former private power scheme and one remaining private scheme. The objective was to assess each place, building, feature and major element for its heritage value, and to make comparative assessments across the whole system. Each site and element was visited and recorded. I was selected to undertake the work partially as a non-engineer who had no detailed knowledge of the system, but also on the basis that I had undertaken extensive broad-scale heritage surveys of regions and building types, including studies of railway sites, the hop industry, lighthouses, jails, port facilities and fortifications. This is important as the assessments incorporated a broad range of values that extend well beyond the technical achievements of the place or item. Often industrial heritage is recognised only for its technical achievement or innovation, but major achievements, such as Hydro Tasmania, are significant for the impact they have had on the economic achievement of the state, for the social changes brought about by bringing a large workforce into the country from overseas, for the creation of towns and local infrastructure, for the impact of construction on major (in this case) wilderness areas, for innovations in rehabilitation, and for the political action taken to prevent development in places such as the Gordon below Franklin, etc., as well as the often extraordinary solutions developed to solve unique engineering problems. Significance is also not always in the large or impressive, but is found in small elements that tell stories of human endeavour. Often abandoned sites or ruins contain significance and the Hydro system contains excellent examples of abandoned and closed sites. This paper explores some of those themes with numerous examples taken across the system to demonstrate how industrial sites have a broad range of heritage values.

Bioassessment of streams with macroinvertebrates: effect of sampled habitat and taxonomic resolution

Two difficult decisions in the design of any bioassessment program based on stream macroinvertebrates are the number and types of habitats that should be sampled and the taxonomic level to which specimens should be identified. We used a large data set from biomonitoring of streams in the greater Sydney region, New South Wales, Australia, to compare bioassessment results obtained with an average-score-per-taxon type of biotic index among several habitats and between the taxonomic levels of family and genus. We evaluated the sensitivity of family- and genus-level indices calculated for 5 habitats (edges of pools, rocks in pools, riffles, aquatic macrophytes, and submerged wood) by considering relationships to chemical and microbial indicators of anthropogenic stress and capacity to distinguish sites affected by human activities from reference sites. Samples from rocks in pools did best on both criteria, and samples from edges of pools also did well. Genus-level index scores were slightly more strongly correlated with environmental variables than were family-level index scores, but taxonomic resolution had virtually no average effect on the degree to which samples from test sites differed from reference status, even though tolerance values for genera differed widely within some families. We attributed the weak effect of greater taxonomic resolution to the small number of identified genera in most families and the fact that many specimens could be identified to family but not to genus. The cost of discrete sampling from multiple habitats might sometimes be justified by its potential to detect habitat-specific impacts at particular sites. However, we conclude that it might be more cost-effective in broad-scale surveys to restrict sampling to the edges of pools, a habitat that occurs widely, or to consider assessment using composites of samples across multiple habitats. The small difference in sensitivity between the family- and genus-level indices suggests that, given its greater cost, bioassessment with fine-level taxonomy may be justified only in special circumstances, such as detection of subtle impacts. A tiered approach, in which only those families with wide intrafamilial variation in tolerance are identified to finer levels, is likely to be more cost-effective than identifying all taxa with fine-level resolution.

Predation Hot Spots: Large Scale Impact of Local Aggregations

Broad scale survey distributions of fish are dominated by some extremely high catches. With a novel survey design we resolved the small-scale fish distribution in the spatio-temporal vicinity of these extreme hauls and showed that in the North Sea they generally do not occur in isolation. An additional case study where stomach contents of fish predators were analyzed revealed that they actually indicate aggregations of piscivorous fish predators on prey aggregations. We show that the predation impact can reach immense dimensions, an aggregation of more than 50 million juvenile cod (Gadus morhua) was entirely wiped out in 5 days by predatory whiting (Merlangius merlangus), aggregating on these juveniles in an area of approximately 18 km2. The consumption of only 32 hot spots of similar magnitude as observed in our study adds up to the average size of an incoming North Sea cod year class. These findings support the hypothesis of predation as the major source of mortality in young-of-the-year demersal fish species and questions the generality of fish aggregation as an effective anti-predator strategy. This study highlights the system-wide structuring force of small-scale predation hot spots and further points to the importance of a more realistic implementation of local high-intensity predation events in food web models.

Field Margin Weed-Species Diversity in Relation to Landscape Attributes and Adjacent Land Use

The importance of managing weeds in seminatural habitats that are adjacent to farm fields is unclear. Weedy-margin vegetation may harbor pests or pathogens and may ALSo serve as source populations for ongoing immigration of weeds into the field. It is ALSo possible, however, that margin vegetation provides habitat for organisms that consume weed seeds or suppress the likelihood of pest or pathogen outbreak. We examined the nature of margin habitat using spatial-scaling of Weed-Species richness as an ecological assay. In 2003, we recorded the occurrence of weedy species along the perimeters of 63 fields in Wisconsin. The fields were distributed within six counties that differed in topography, geological history, local climate, and soil type and which spanned the range of variability in the agricultural landscape. We identified seven habitats that differed in geology and land use. The relationship between species richness and margin class was estimated using an analog of the power law. Additionally, we investigated broadscale correlates of habitat heterogeneity at the field level, using a modeling strategy that included additional explanatory factors logically connected to plant diversity. Using a model-confrontation approach, the survey supported the inclusion of two topographical diversity indices, elevation gradient and a field-shape index, into our model. Our broadscale survey provides information on one of a suite of important considerations needed to make decisions about the importance of managing weeds in field margins.

Effect of highway construction on plant diversity of grassland communities in the permafrost regions of the Qinghai - Tibet plateau

During 2002–2004, a broad-scale survey on the plant diversity of grassland communities along a natural elevation gradient in the permafrost regions of the Qinghai–Tibet plateau, China, was conducted to investigate the effect of highway construction nearly 30 years ago. Richness index was not significantly different among undisturbed communities (Kobresia pygmaea meadow, K. humilis meadow, Stipa purpurea steppe, Carex moorcroftii steppe), but significant differences (P &lt; 0.05) were observed for evenness and diversity indices among four undisturbed communities. Three indices significantly decreased from communities 100 m (lightly disturbed communities), 200 m (undisturbed communities), and 50 m (severely disturbed communities) from the Qinghai–Xicang Highway, and three indices of severely disturbed communities were similar to that of 30 m communities (extremely-severely disturbed communities). Diversity and richness indices peaked at intermediate elevations of 4720 m in undisturbed communities and lightly disturbed communities, but were uniform in the severely disturbed communities and extremely-severely disturbed communities along with the increase of elevation. β-Diversity decreased in communities at 30, 50, and 100–200 m distance from the highway. This indicated that β-diversity of communities was enhanced with the increase of disturbance for each grassland type in the study region. Both undisturbed and disturbed communities showed the same changeable bell-shaped trend with elevation increase, increasing from 4320–4620 m, decreasing from 4720 to 4920 m, and peaking at 4620 to ~4720 m, indicating that elevation from 4620–4720 m was a transition zone in permafrost region.

Biological control of the vernal population increase of Calanus finmarchicus on Georges Bank

Abstract An adjoint data assimilation approach was used to quantify the physical and biological controls on Calanus finmarchicus N3–C6 stages on Georges Bank and its nearby environs. The mean seasonal cycle of vertically averaged distributions, from 5 years of the GLOBEC Georges Bank Broad-Scale Surveys between January and June, was assimilated into a physical–biological model based on the climatological circulation. Large seasonal and spatial variability is present in the inferred supply sources, mortality rates, computed molting fluxes, and physical transports. Estimated mortalities fall within the range of observed rates, and exhibit stage structure that is consistent with earlier findings. Inferred off-bank initial conditions indicate that the deep basins in the Gulf of Maine are source regions of early stage nauplii and late-stage copepodids in January. However, the population increase on Georges Bank from January to April is controlled mostly by local biological processes. Magnitudes of the physical transport terms are nearly as large as the mortality and molting fluxes, but their bank-wide averages are small in comparison to the biological terms. The hypothesis of local biological control is tested in a sensitivity experiment in which upstream sources are set to zero. In that solution, the lack of upstream sources is compensated by a decrease in mortality that is much smaller than the uncertainty in observational estimates.

A*CENSUS (Archival Census and Education Needs Survey in the United States)

The A*CENSUS—Archival Census and Education Needs Survey in the United States—is the first broadscale survey of individual archivists in the United States in nearly thirty years. The survey, conducted by mail and online during a two-month period in 2004, asked archivists about their positions, employers, demographics, credentials, job functions and specialization, salaries, career paths, issues, professional identity, and affiliation. There were additional questions for those with management responsibilities, and specific questions for members of certain professional associations. Inclusive in scope and deep in detail, A*CENSUS has produced a comprehensive picture of the archival profession and its people early in the twenty-first century.