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The Antarctic silverfish Pleuragramma antarctica is a key species in the Southern Ocean ecosystem, and it is potentially threatened by the climate change affecting Antarctic ecosystems. Assessing the possible exposure to similar or different environmental conditions at early life stages and gathering information about connectivity or segregation between local populations of P. antarctica can be key for planning sound management strategies for this species. By using Laser Ablation Inductively Coupled Plasma Mass Spectrometry, we characterized the otolith chemical composition of 163 adult Antarctic silverfish collected from three areas located thousands of kilometers apart from each other: Cape Hallett, Adelie Land, and Joinville Island. Otoliths were analyzed for chemical composition of both the edge (reflecting the exposure of individuals to environmental conditions at the site where they were sampled) and the core (reflecting exposure to environmental conditions during early life periods after the egg fertilization). We found that the chemical composition along otolith edges was heterogeneous between samples collected at Joinville Island and those collected at the other two sampling areas. In contrast, the chemical composition of otolith cores was homogenous. Our study suggests that adult Antarctic silverfish inhabiting areas very distant from each other have been exposed to similar environmental conditions at early life stages, and could have experienced similar growth rates and physiological processes. This would imply that environmental drivers probably do not play a role in determining potential spatial variability in individual fitness at early life stages, and should not have a major impact on population replenishment.

This is an eclectic review and analysis of contemporary and promising stable isotope methodologies to study the biology and ecology of arthropods. It is augmented with literature from other disciplines, indicative of the potential for knowledge transfer. It is demonstrated that stable isotopes can be used to understand fundamental processes in the biology and ecology of arthropods, which range from nutrition and resource allocation to dispersal, food-web structure, predation, etc. It is concluded that falling costs and reduced complexity of isotope analysis, besides the emergence of new analytical methods, are likely to improve access to isotope technology for arthropod studies still further. Stable isotopes pose no environmental threat and do not change the chemistry or biology of the target organism or system. These therefore represent ideal tracers for field and ecophysiological studies, thereby avoiding reductionist experimentation and encouraging more holistic approaches. Considering (i) the ease with which insects and other arthropods can be marked, (ii) minimal impact of the label on their behaviour, physiology, and ecology, and (iii) environmental safety, we advocate more widespread application of stable isotope technology in arthropod studies and present a variety of potential uses.

Like many native endemic desert freshwater fish species, the June Sucker (Chasmistes liorus) is currently listed as endangered. Managers have increasingly turned to habitat restoration as a key component to recovery plans. For endangered species, one of the primary outcomes of habitat restoration is that it should result in successful reproduction and recruitment of individuals into the adult population. Confirmation of natural recruitment as a function of habitat restoration can only be achieved by establishing natal origins. Recent research has proven the validity of otolith microchemistry, a technique that analyzes small quantities of elements, to trace potamodromous fish to their natal tributaries. Previous studies have documented that localized habitats in terms of microchemistry are reflected in otolith composition, thereby potentially making this a valuable way of determining fish origins. The primary goal of this study is to use otolith microchemistry to establish natal origins of June Sucker, ultimately in order to evaluate whether tributary habitat restoration results in natural recruitment. To accomplish this I first determined if the water chemistry among the three main spawning tributaries differed from one another. Second, I determined if the otolith chemistry reflected the otolith chemistry. Lastly, I developed a statistical model capable of classifying fish to their respective tributary based the element:calcium ratios in the otolith microchemistry. Water chemistry differed significantly among all three spawning tributaries, and I observed a strong and significant relationship between otolith chemistry and water chemistry. The classification models based on otolith element:Ca signatures were capable of accurately classifying individual fish to their natal tributary (classification tree 89% accuracy; random forest model 91% accuracy), increasing the ability to determine if the fish���s origin is wild vs. hatchery. The data obtained from this study will advance the current understanding of the June sucker recruitment dynamics and result in a fundamental improvement in our ability to determine where natural recruitment into the adult spawning population is occurring. In addition, this knowledge may help evaluate factors limiting recruitment in Utah Lake tributaries, identify future restoration localities, and assist effectiveness monitoring of spawning habitat restoration efforts.

Strontium isotopes simultaneously delineate fine-scale natal habitats and migrations of Pacific salmon harvested during a coastal commercial fishery., Highly migratory organisms present major challenges to conservation efforts. This is especially true for exploited anadromous fish species, which exhibit long-range dispersals from natal sites, complex population structures, and extensive mixing of distinct populations during exploitation. By tracing the migratory histories of individual Chinook salmon caught in fisheries using strontium isotopes, we determined the relative production of natal habitats at fine spatial scales and different life histories. Although strontium isotopes have been widely used in provenance research, we present a new robust framework to simultaneously assess natal sources and migrations of individuals within fishery harvests through time. Our results pave the way for investigating how fine-scale habitat production and life histories of salmon respond to perturbations—providing crucial insights for conservation.

Trace elemental signatures incorporated into calcified structures in fish and mollusk larvae have been used to reveal population connectivity and larval dispersal trajectories. To determine whether trace element analysis could be applied to larvae that do not permanently retain calcified structures, we raised larvae of the porcelain crab Petrolisthes cinctipes from multiple locations along the northern California, USA, coast in a common water source for up to 8 wk. We analyzed 20 elements in extractions of soft tissues from embryos and the 2 larval and 1 postlarval stages. Elemental signatures of individuals in each developmental stage were compared to an atlas of signatures from each collection site using discriminant analysis to determine whether larvae could be accurately assigned to their site of origin in 2 ways. First, postlarvae were classified using a natal site atlas constructed using embryonic signatures from each site, and this classification had poor success (average 39.7% correct). Second, larvae of each stage were classified using a natal site atlas constructed using signatures of larvae from that same stage. This yielded considerably better classification success (81.7% correct overall). Thus, the same trace element signatures were not consistently maintained from embryos to postlarvae, but differences in signatures among natal sites were maintained during the larval period. Trace element signatures in soft tissues could be useful in tracking dispersal between stages and determining how many sites, rather than which sites, contributed to a cohort of larvae or settlers. © Inter-Research 2013.

Despite a commitment by the European Union to protect its migratory bat populations, conservation efforts are hindered by a poor understanding of bat migratory strategies and connectivity between breeding and wintering grounds. Traditional methods like mark-recapture are ineffective to study broad-scale bat migratory patterns. Stable hydrogen isotopes (dD) have been proven useful in establishing spatial migratory connectivity of animal populations. Before applying this tool, the method was calibrated using bat samples of known origin. Here we established the potential of dD as a robust geographical tracer of breeding origins of European bats by measuring dD in hair of five sedentary bat species from 45 locations throughout Europe. The dD of bat hair strongly correlated with well-established spatial isotopic patterns in mean annual precipitation in Europe, and therefore was highly correlated with latitude. We calculated a linear mixed-effects model, with species as random effect, linking dD of bat hair to precipitation dD of the areas of hair growth. This model can be used to predict breeding origins of European migrating bats. We used d13C and d15N to discriminate among potential origins of bats, and found that these isotopes can be used as variables to further refine origin predictions. A triple-isotope approach could thereby pinpoint populations or subpopulations that have distinct origins. Our results further corroborated stable isotope analysis as a powerful method to delineate animal migrations in Europe

We analyzed mtDNA control region sequences of green turtles (Chelonia mydas) from Arvoredo Island, a foraging ground in southern Brazil, and identified eight haplotypes. Of these, CM-A8 (64%) and CM-A5 (22%) were dominant, the remainder presenting low frequencies (< 5%). Haplotype (h) and nucleotide ( π) diversities were 0.5570 ± 0.0697 and 0.0021 ± 0.0016, respectively. Exact tests of differentiation and AMOVA ΦST pairwise values between the study area and eight other Atlantic foraging grounds revealed significant differences in most areas, except Ubatuba and Rocas/Noronha, in Brazil (p > 0.05). Mixed Stock Analysis, incorporating eleven Atlantic and one Mediterranean rookery as possible sources of individuals, indicated Ascension and Aves islands as the main contributing stocks to the Arvoredo aggregation (68.01% and 22.96%, respectively). These results demonstrate the extensive relationships between Arvoredo Island and other Atlantic foraging and breeding areas. Such an understanding provides a framework for establishing adequate management and conservation strategies for this endangered species.

Beetle exoskeletons contain chitin, a poly amino-sugar that is biosynthesized incorporating hydrogen isotopes from diet and water. As the stable isotope ratios D/H (or H-2/H-1, expressed as delta D values) of precipitation and diet are jointly influenced by climate, the biochemically recorded hydrogen-isotope ratio in fossil beetle exoskeleton has the potential to be used for paleoclimatic reconstruction. New delta D data from modern beetles are presented as a preliminary database for Europe, with a re-evaluation of earlier North American data. We present correlated matrices of delta D values in modern beetle chitin and modern precipitation to demonstrate the concept. We review the pertinent literature to highlight the history, utility, and likely future research directions for the use of chitin's stable isotopes in entomological paleoclimatology. (c) 2006 Elsevier Ltd. All rights reserved.