328 research outputs found
"We are all Here to Stay"; Addressing Aboriginal Title Claims after Delgamuukw v British Columbia
This article outlines how the Canadian courts dealt with the interface between aboriginal title and common law notions of property throughout the various Delgamuukw decisions. Through examination of the different judgments in the case, at different judicial levels, the article traverses issues around the source of aboriginal title, and subsequent limitations on the content of aboriginal title which arise from that. The article concludes that the unique concept of aboriginal title cannot be interpreted within the paradigm of the common law. The article further concludes that courts are the wrong forum for adjudicating aboriginal claims. 
Is Hyde Park Hiding the Truth? An Analysis of the Public Interest Defence to Copyright Infringement
The existence, or not, of a public interest defence in the sphere of copyright law has been an issue of contention for many years. Due to the comprehensive statutory fair dealing defences available, only a handful of defendants have sought to rely on this defence, which exists at common law. However, when the defence has been raised, the judges have been unable to reach a consensus on its status, scope and indeed availability as a defence to breach of copyright.This paper analyses the extent to which public interest concerns are addressed in statutory copyright law, and presents arguments in support of extending the common law public interest defence to copyright law. However, any such defence must be limited in its scope and applicability, so as to avoid becoming a "thieves charter"
A New 76Ge Double Beta Decay Experiment at LNGS
This Letter of Intent has been submitted to the Scientific Committee of the
INFN Laboratori Nazionali del Gran Sasso (LNGS) in March 2004. It describes a
novel facility at the LNGS to study the double beta decay of 76Ge using an
(optionally active) cryogenic fluid shield. The setup will allow to scrutinize
with high significance on a short time scale the current evidence for
neutrinoless double beta decay of 76Ge using the existing 76Ge diodes from the
previous Heidelberg-Moscow and IGEX experiments. An increase in the lifetime
limit can be achieved by adding more enriched detectors, remaining thereby
background-free up to a few 100 kg-years of exposure.Comment: 67 pages, 19 eps figures, 17 tables, gzipped tar fil
Spatial, temporal and within-species variation in the foraging ecology of a marine predator across a dynamic seascape
Spatial, temporal and within-species variation in the foraging ecology among consumers add to the complexities of trophic structure and its processes across all biomes on Earth. In this dissertation, I investigated the foraging ecology and plasticity of an ice-adapted marine predator, the ringed seal (Pusa hispida), inhabiting the Arctic marine environment – a dynamic seascape undergoing rapid climatic changes – across age, space and time using stable isotope analysis and animal satellite telemetry. I used a long-term dataset (1990 – 2013) of ringed seal muscle (n = 630) and liver (n = 558) samples, as well as satellite telemetry data (1999-2013; n= 132) collected from seven locations across the Arctic of varying latitude (56ºN – 76ºN) and longitude (-117ºW – -61ºW). I first quantified the general increase in δ13C and δ15N values of three tissues from eight arctic marine mammal species after chemical lipid extraction with results varying across species, developed species- and tissue-specific lipid normalization models, and a species-tissue-specific decision framework for the best lipid correction approach. I then quantified spatial and temporal variation of ringed seal dietary prey contributions, isotopic niche size and trophic position during ontogeny across the Arctic. I found a general latitudinal trend where the level of fish consumption and trophic position of ringed seals decreased due to increased prevalence of sub-arctic fish species and less trophic complexity in the zooplankton community at lower latitudes. As well, isotopic niche size for ringed seals and beluga whales (Delphinapterus leucas) increased at lower latitudes and level of individual specialization in ringed seals increased at lower latitudes as a response to large-scale spatial variation in ecological opportunity (i.e. prey species richness) which is higher at lower latitudes. Using satellite telemetry, I found that individuals from higher latitudes, which undergo shorter ice-free seasons, spend more time traveling and less time foraging than individuals from lower latitudes where the ice-free season is longer. Also, smaller individuals spent more time transiting between habitat patches than their larger conspecifics due to competitive exclusion. Overall, these findings highlight the foraging plasticity of ringed seals to changing environmental conditions and resource availability
Seasonal Movements and Diving of Ringed Seals, Pusa hispida, in the Western Canadian Arctic, 1999–2001 and 2010–11
Satellite-linked time-depth recorders were deployed on 17 ringed seals in early summer in 1999, 2000, and 2010, near the Inuvialuit community of Ulukhaktok, Northwest Territories, Canada. The main objective was to investigate movements and diving behaviour of ringed seals in the Prince Albert Sound (PAS) and eastern Amundsen Gulf (EAG) regions in relation to season, sex, and age-class. Tags performed well on 16 of 17 tagged seals, with average tracking periods of 256 d (SD 69, range: 134 – 352). Adult and subadult ringed seals traveled considerable distances throughout the open water period (mean = 5844 km, range = 1232 – 9473 km), using vast home ranges during this season, shown with 90 Percent Volume Contours (90 PVC) averaging 122 854 km2 for subadults, 76 658 km2 for adult females, and 21 649 km2 for adult males. Overall, adults spent 69.5% of the observed open water days in foraging/resident mode and 22.8% in traveling mode. The majority (75%) of total observed foraging/resident time was spent in PAS and EAG. Eleven of 12 adults made forays outside EAG and PAS to distant areas, including Prince of Wales Strait (7 seals), Viscount Melville Sound (6), Minto Inlet (4), western Amundsen Gulf (4), and six other zones. During open water season, subadults spent 36.8% traveling and 51.4% foraging/ resident, also mainly in EAG and PAS (61%), but they all traveled to distant zones, eight in total. During winter, all tagged adult females, five of seven adult males, and three of four subadults returned to PAS and EAG to occupy winter home ranges that were on average 15% of the size of the open water home range (mean winter ranges = 1299 km2 for adult males, 3599 km2 for adult females, and 30 499 km2 for subadults). The mean size of the winter home ranges varied by as much as a factor of 10 among the three winters examined. Seal movements were most restricted during the winters with extensive fast ice (1999 – 2000 and 2010 – 11) and least restricted during the winter (2000 – 01) when fast ice did not form in EAG. In winter, adult females made more long, deep dives than either adult males or subadults.Des enregistreurs de profondeur temporelle en liaison avec un satellite ont été déployés sur 17 phoques annelés au début des étés 1999, 2000 et 2010 près de la collectivité inuvialuite d’Ulukhaktok, dans les Territoires du Nord-Ouest, au Canada. L’objectif principal consistait à étudier les déplacements et les comportements de plongée des phoques annelés des régions du détroit de Prince-Albert (DPA) et de la partie est du golfe Amundsen (EGA) en fonction de la saison, du sexe et de la classe d’âge. Les étiquettes ont donné des résultats valables dans le cas de 16 des 17 phoques étiquetés, les périodes moyennes de pistage ayant atteint 256 jours (SD 69, étendue : 134 – 352). Les phoques annelés adultes et jeunes adultes parcouraient des distances considérables pendant la période des eaux libres (moyenne = 5 844 km, étendue = 1 232 – 9 473 km), dans de vastes domaines vitaux au cours de la saison. Les pourcentages du volume des contours de 90 (90 PVC) s’établissaient en moyenne à 122 854 km2 pour les jeunes adultes, à 76 658 km2 pour les femelles adultes et à 21 649 km2 pour les mâles adultes. Dans l’ensemble, les adultes ont passé 69,5 % des journées observées en eaux libres en mode d’alimentation et de résidence, et 22,8 % en mode de déplacement. La majorité (75 %) du temps total observé en mode d’alimentation et de résidence était dans le DPA et l’EGA. Onze adultes sur 12 se sont aventurés en dehors du DPA et de l’EGA pour atteindre des endroits éloignés, dont le détroit du Prince-de-Galles (7 phoques), le détroit du Vicomte de Melville (6), l’anse Mintot (4), l’ouest du golfe Amundsen (4) et six autres zones. Pendant la saison des eaux libres, les jeunes adultes ont passé 36,8 % du temps en mode de déplacement et 51,4 % du temps en mode d’alimentation ou de résidence, également principalement dans le DPG et l’EGA (61 %), mais ils se sont tous rendus dans des zones éloignées, huit en tout. Durant l’hiver, toutes les femelles adultes étiquetées, cinq mâles adultes sur sept et trois jeunes adultes sur quatre sont revenus dans le DPA et l’EGA pour occuper des domaines vitaux hivernaux qui correspondaient, en moyenne, à 15 % de la taille du domaine vital en eaux libres (étendues moyennes des domaines hivernaux = 1 299 km2 pour les mâles adultes, 3 599 km2 pour les femelles adultes et 30 499 km2 pour les jeunes adultes). La taille moyenne des domaines vitaux hivernaux a varié en fonction d’un facteur de 10 au cours des trois hivers à l’étude. Le déplacement des phoques était plus restreint pendant les hivers où la glace était rapide (1999-2000 et 2010-2011) et moins restreint pendant l’hiver (2000-2001) où la glace rapide ne s’est pas formée dans l’EGA. L’hiver, les femelles adultes faisaient plus de plongées longues et profondes que les mâles adultes ou les jeunes adultes
Multi-cusped postcanine teeth are associated with zooplankton feeding in phocid seals
Tooth morphologies often reflect diet in animals. Among marine mammals, a well-known example is krill-feeding crabeater seals (Lobodon carcinophaga), in which complex, comb-like postcanine teeth function as a sieve by retaining krill inside their mouth while expelling water. However, information on teeth morphology and function is scarce for other seal species. A recent bio-logging study found that Baikal seals (Pusa sibirica) feed on tiny pelagic amphipods at remarkably high rates with highly multi-cusped postcanine teeth, highlighting the need for comparative analyses on teeth morphologies and diets in phocid seals. Here, we quantified postcanine teeth morphology for 13 seal species based on museum skull specimens, with a particular focus on Baikal seals and their related species (genus Pusa and Phoca). The species in Pusa, including Baikal seals, had more specialized multi-cusped postcanine teeth than Phoca species, reflecting higher zooplankton proportions in their diets. Postcanine teeth of Baikal seals exhibited the highest degree of specialization among Pusa, even when the effect of age-related wear is controlled for. This result agrees with the highest zooplankton preference in this species. Further, we found a strong positive correlation between the degree of specialization in postcanine teeth and zooplankton reliance across phocid seal species. Our findings indicate that the functional role of multi-cusped postcanine teeth as a sieve is not limited to crabeater seals but prevail in many phocid seals feeding on zooplankton.journal articl
Comparing temporal patterns in body condition of ringed seals living within their core geographic range with those living at the edge
Ecological theory suggests that demographic responses by populations to environmental change vary depending on whether individuals inhabit central or peripheral regions within the species’ geographic range. Here, we tested this prediction by comparing a population of ringed seals Pusa hispida located at high latitudes as part of their core range (core) with a population located at the southern extremity of their range (peripheral). First, we compared the two regions’ environmental trends in timing of sea-ice breakup and freeze-up, open-water duration and the North Atlantic Oscillation (NAO). We found that the core region shifted to progressively warmer conditions in the early 1990s; whereas, in the peripheral region, the warming trend shifted in 1999 to one with no warming trend but high inter-annual variability. Next, we examined how body condition, inferred from blubber depth, responded to temporal changes in sea-ice and climatic variables – variables that have been shown to influence ringed seal demography. Core seals displayed minimal seasonal changes in body condition; whereas peripheral seals displayed a 20–60% amplitude seasonal change in body condition with a phase shift to earlier initiation of fat accumulation and loss. Finally, we tested for interannual differences and found that both core and peripheral seals responded similarly with decreased body condition following more positive NAO. Environmental variables influenced body condition in opposite directions between the two regions with core seals declining in body condition with later spring breakup and shorter open-water duration, whereas peripheral seals showed opposite relationships. Seals living at the core likely benefit from an evolved match between adaptation and environmental variation resulting in dampened seasonal and interannual fluctuations in body condition. Knowledge of how different populations respond to environmental change depending on geographic location within a species range can assist in anticipating population specific responses to climate warming
A review of statistical models used to characterize species-habitat associations with animal movement data
Understanding species-habitat associations is fundamental to ecological
sciences and for species conservation. Consequently, various statistical
approaches have been designed to infer species-habitat associations. Due to
their conceptual and mathematical differences, these methods can yield
contrasting results. In this paper, we describe and compare commonly used
statistical models that relate animal movement data to environmental data.
Specifically, we examined selection functions which include resource selection
function (RSF) and step-selection function (SSF), as well as hidden Markov
models (HMMs) and related methods such as state-space models. We demonstrate
differences in assumptions of each method while highlighting advantages and
limitations. Additionally, we provide guidance on selecting the most
appropriate statistical method based on research objectives and intended
inference. To demonstrate the varying ecological insights derived from each
statistical model, we apply them to the movement track of a single ringed seal
in a case study. For example, the RSF indicated selection of areas with high
prey diversity, whereas the SSFs indicated no discernable relationship with
prey diversity. Furthermore, the HMM reveals variable associations with prey
diversity across different behaviors. Notably, the three models identified
different important areas. This case study highlights the critical significance
of selecting the appropriate model to identify species-habitat relationships
and specific areas of importance. Our comprehensive review provides the
foundational information required for making informed decisions when choosing
the most suitable statistical methods to address specific questions, such as
identifying expansive corridors or protected zones, understanding movement
patterns, or studying behaviours
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