Transcending scale dependence in identifying habitat with resource selection functions

Multi-scale resource selection modeling is used to identify factors that limit species distributions across scales of space and time. This multi-scale nature of habitat suitability complicates the translation of inferences to single, spatial depictions of habitat required for conservation of species. We estimated resource selection functions (RSFs) across three scales for a threatened ungulate, woodland caribou (Rangifer tarandus caribou), with two objectives: (1) to infer the relative effects of two forms of anthropogenic disturbance (forestry and linear features) on woodland caribou distributions at multiple scales and (2) to estimate scale-integrated resource selection functions (SRSFs) that synthesize results across scales for management-oriented habitat suitability mapping. We found a previously undocumented scale-specific switch in woodland caribou response to two forms of anthropogenic disturbance. Caribou avoided forestry cut-blocks at broad scales according to first- and second-order RSFs and avoided linear features at fine scales according to third-order RSFs, corroborating predictions developed according to predator-mediated effects of each disturbance type. Additionally, a single SRSF validated as well as each of three single-scale RSFs when estimating habitat suitability across three different spatial scales of prediction. We demonstrate that a single SRSF can be applied to predict relative habitat suitability at both local and landscape scales in support of critical habitat identification and species recovery.     

Seasonal distribution patterns of juvenile loggerhead sea turtles (<Emphasis Type="Italic">Caretta caretta</Emphasis>) following capture from a shipping channel in the Northwest Atlantic Ocean

Thirty-four juvenile loggerhead sea turtles captured by trawling from the Charleston, South Carolina (USA), shipping channel (32°42′N; −79°47′W) between May 2004 and August 2007 were tagged with satellite transmitters to assess the extent to which they remained near the capture location given their collection along a seasonal migratory corridor. Seventy-five percent of juveniles were classified as seasonal residents. Migrants predominantly swam north in the spring and nomads wandered south in the summer, but predictive indicators for non-resident status were not identified. All but one juvenile generally remained south of 34°N, within 40 km of shore, and in waters <30 m deep throughout the year. Nine of 14 loggerhead sea turtles monitored during the winter remained exclusively over the continental shelf, three briefly occurred in oceanic habitats, and two foraged extensively in oceanic habitats. Residents distributed >15 km from shore between spring and autumn were three times as likely to occur in oceanic habitats in winter. Modest seasonal movements contrasted with adults tagged at similar latitudes and with juveniles tagged further north and suggest distinct foraging groups within a regional foraging ground.     

Soil nutrient supply modulates temperature-induction cues in mast-seeding grasses

Synchronous and intermittent reproduction in long-lived plants, known as mast seeding, is induced by climatic cues, but the mechanism explaining variation in masting among neighboring but edaphically segregated species is unknown. Soil nutrients can enhance flowering, and thus, populations on nutrient-rich soils may require less-favorable growing temperatures to flower. We tested this hypothesis by predicting the probability of flowering in response to air temperature for five species of alpine Chionochloa grasses in South Island, New Zealand, over 37 years and relating our predictions to soil N supply (NH4(+) + NO3(-)). Summer air temperatures better predicted flowering than spring air temperatures, which were correlated with soil N mineralization. Species on N-rich soils required lower mean temperatures to induce flowering and/or responded more consistently across a gradient of air temperatures, contributing to the higher probability of their tillers and tussocks flowering at low summer temperatures. Our results suggest that flowering primarily occurs in response to warm summer temperatures, but species on N-rich soils require less favorable growing conditions because they invest relatively less N in seeds. Thus, predicting masting requires a consideration of the interactions among climate, the internal resources of plants, and mineral nutrient uptake.     

Multi-scale foraging variability in Northern gannet (Morus bassanus) fuels potential foraging plasticity

The survival of marine predators depends on behavioural plasticity to cope with changes in prey distribution. Variability in behaviour might predict plasticity and is easier to assess than plasticity. Using miniaturized GPS loggers over several breeding seasons in two Norwegian Northern gannet (Morus bassanus) colonies, we investigated if and how the variability within and between individuals, but also between colonies and years, affected foraging strategies. Results revealed strong individual variability (foraging trip durations, foraging effort and different foraging areas). Individuals from both colonies showed preferred commuting routes, flight bearings and feeding hotspots. Individuals from the largest colony used larger and more foraging areas than individuals from the small colony. Feeding hotspots and foraging ranges varied amongst years in the largest colony only. Our study demonstrated that gannets show flexibility by changing prey fields that are driven by shifting oceanographic conditions.     

Recent shoreline evolution and beach erosion along the central Adriatic coast of Italy: the case of Molise region

A study on the modern dynamics and shoreline changes from 1954 to 2014 of the Molise coast (central Adriatic Sea) has been carried out. Short to long-term shoreline changes and associated surface area variations have been assessed in GIS environment for the study coast, subdivided in nine coastal segments (S1-S9), by using 100-m regularly spaced transects. In addition, the possible influence of natural and anthropogenic factors, especially of climatic variability and engineered shoreline defense structures, has been investigated. The Molise coast has experienced notable long-term erosion (period 1054-2014) that caused an overall coastal land loss of approximately 940,000 m². Erosion was, yet, limited to coastal segments S1 and S7, nearest to the mouths of major rivers, namely Trigno and Biferno, while the major part of the study coast has remained essentially stable or even advanced. Increased shoreline protection by defense structures has generally favoured shoreline stability and frequently generated shoreline advance, except for segments S1 and S7. Observed differences in shoreline change rates over time at the decadal to interannual scale, have not find a response in the analysis of available data on meteo-marine conditions of the Molise coast and climate variability indices, pointing out the need to improve knowledge on meteomarine conditions and on climatic variability forcing of the study area. From 2004 to 2014, the Molise shoreline remained essentially stable. Nonetheless, most recent shoreline changes (period 2011-2014) and modern shoreline dynamics indicate that erosion has become more widespread, involving at least part of segments S2-S3 and S8-S9, located south of the river mouth segments. The localized long-term shoreline retreat and most recent shoreline erosion appear to be primarily related to channel adjustments of the Biferno and Trigno rivers that occurred since the 1950s under the control of human interventions on the rivers, especially the construction respectively of a dam and a check dam along their lower courses, that trap of most of their solid load, affecting so adversely the sediment budget of the river mouths areas and adjacent beaches. Overall data acquired on the recent shoreline evolution and modern shoreline dynamics of the Molise coast and on related causal factors provide a good basic knowledge for regional coastal management purposes, and for further scientific purposes. Particularly, they suggest the opportunity to deepen a number of aspects such as the relationship between the coast and river catchments feeding it, the possible influences on the Molise shoreline dynamics of the neighbouring coasts, the efficiency/obsolescence of defense structures and the present-day vulnerability to coastal erosion of the Molise coast.     

Development and environmental application of a genus-specific quantitative PCR approach for Pseudo-nitzschia species

Quantitative polymerase chain reaction (qPCR) for the identification and quantification of microbes has become a common tool for the study of harmful algal blooms (HABs). We developed a qPCR method for the diatom genus Pseudo-nitzschia. Several species of this genus form toxic blooms through the production of the neurotoxin domoic acid (DA). Outbreaks of toxicity attributed to DA along the US west coast have caused sickness and death of marine mammals and seabirds through food web contamination. The method developed here quantifies Pseudo-nitzschia spp. at low abundances in natural samples, thereby, providing a method to improve our understanding of the environmental conditions leading to blooms of these species. This has been accomplished previously by techniques for identification and quantification that are slow and laborious compared to qPCR. The approach was successfully tested and validated using eight species of Pseudo-nitzschia and 33 non-target organisms and employed to follow local bloom dynamics.     

Effects of temperature variation on TSD in turtle (C. picta) populations

We formulate a two-sex model of temperature-dependent sex determination (TSD) for a freshwater turtle (C. picta) population. The aim is to understand how environmental temperature variations and nest heat conduction properties affect the long term dynamics of the population. This is a key to understanding how global temperature changes may affect their survival. With stochastic inputs of ambient temperature and solar radiation, the model uses the heat equation to determine the temperature in the egg layer in the nest; in turn, this determines the sex ratio in the egg clutch using a variable degree-day model. Finally, a nonlinear Leslie type, stage-based, two-sex model, is used to determine the long term male and female populations. A two-sex model is required because of different development rates for males and females. The model is flexible enough to enable other researchers to examine the effects of temperature variation variations on other species with TSD, e.g., crocodilians, reptilians, as well as other turtle species. It can be adapted to study effects of nest location, soil type, rain events, different incubation periods, and density effects, for example, the dependence of the mating function on the ratio of males to females and each’s contribution to the sex of hatchlings. Modifications can be easily made to fit a specific life history traits. The model is a beginning step in understanding the long term, high fitness shown by many reptile species with TSD, and it may suggest to experimentalists what data may be relevant to these issues; it can also be useful to wildlife managers in developing strategies for intervention if needed. Among the principal findings are that temperature variability and detailed nest heat conduction properties may buffer projected negative effects on a population.     

A heuristic approach to predicting water beetle diversity in temporary and fluctuating waters

An understanding of the causal mechanisms and processes that shape macroinvertebrate communities at a local scale has important implications for the management and conservation of freshwater biodiversity. Here we compare the performance of linear and non-linear statistics to explore diversity-environment relationships using data from 76 temporary and fluctuating ponds in two regions of southern England. We focus on aquatic beetle assemblages, which have been shown to be excellent surrogates of wider freshwater macroinvertebrate diversity. Ponds in the region contained a rich coleopteran fauna, totaling 68 species, which provided an excellent model system with which to compare the performance of two non-linear procedures (artificial neural networks—ANNs and generalised additive models—GAMs) and one more traditional linear approach (Multiple linear regression—MLR) to modelling diversity-environment relationships. Of all approaches employed, the best fit was obtained using an ANN model with only four input variables (conductivity, turbidity, magnesium concentration and depth). This model accounted for 82% of the observed variability in Shannon diversity index across ponds. In contrast, the best GAM and MLR models only explained 50% and 14% of this variation, respectively. Contribution profile analysis of conductivity, turbidity, magnesium concentration and depth, obtained from the best fit ANN through a hierarchical cluster analysis, allowed the identification of direct and proxy effects in relation to the environmental variables measured in this study. In each case, distinct clusters of ponds were identified in contribution profile analysis, suggesting that ponds across the two regions fall into a number of discrete groups, whose beetle faunas respond in subtly yet significantly different ways to key environmental variables. Aquatic coleopteran diversity in ponds in the two regions appears to be driven at a local scale by changes in relatively few physicochemical gradients, which are related to diversity in a clearly non-linear manner.     

Handheld-Assisted Field Data Collection for Occupational Risk Assessment

A computerized handheld procedure is presented in this paper. It is intended as a database complementary tool, to enhance prospective risk analysis in the field of occupational health. The Pendragon forms software (version 3.2) has been used to implement acquisition procedures on Personal Digital Assistants (PDAs) and to transfer data to a computer in an MS-Access format. The data acquisition strategy proposed relies on the risk assessment method practiced at the Institute of Occupational Health Sciences (IST). It involves the use of a systematic hazard list and semi-quantitative risk assessment scales. A set of 7 modular forms has been developed to cover the basic need of field audits. Despite the minor drawbacks observed, the results obtained so far show that handhelds are adequate to support field risk assessment and follow-up activities. Further improvements must still be made in order to increase the tool effectiveness and field adequacy.     

The Indigenous Fisherman Divers of Thailand: Diving-Related Mortality and Morbidity

The Urak Lawoi are indigenous fishermen on Thailand’s west coast. The population includes an estimated 400 divers who dive using surface-supplied compressed air. In a cross-sectional survey conducted among the 6 major communities of Urak Lawoi, questionnaire-based interviews were administered to active divers, ex-divers, and families or colleagues of divers who had died in the previous 5 years. Six deaths resulting from diving-related accidents were identified, indicating a diving-related mortality rate of approximately 300 per 100,000 person-years, while in the same 5-year period 11 divers had been disabled owing to diving-related events, indicating a diving-related disabling event rate of approximately 550 per 100,000 person-years. Among 342 active divers interviewed, one third reported having suffered from decompression illness, although based on reported current symptoms over 50% were classified as suffering from recurring non-disabling decompression illness. Physical examination conducted on a subset of 98 active divers revealed the presence of spinal injury (clonus, raised muscle tone, and heightened reflexes) and of joint damage (pain in one or more joint, crepitus, or restricted movement) in 24 and 30% respectively. Improved primary prevention and medical treatment are needed to reduce mortality and morbidity among this population.