Dietary composition of endangered seahorses determined by stable isotope analysis

2017 ◽  
Vol 68 (5) ◽  
pp. 831 ◽  
Author(s):  
S. Valladares ◽  
D. X. Soto ◽  
M. Planas
Keyword(s):  
Stable Isotope ◽  
Environmental Changes ◽  
Conservation Status ◽  
Management Strategies ◽  
Isotope Analysis ◽  
Primary Source ◽  
Habitat Characteristics ◽  
Conservation Actions ◽  
Isotope Mixing Models ◽  
North Western

The lack of integrated measures for assessing the feeding ecology of seahorses may restrict the effectiveness of conservation actions on wild populations of worldwide threatened seahorse species. Identifying dietary sources will allow researchers to determine their degree of vulnerability to environmental changes, redefine their conservation status and apply appropriate management strategies. The resource use of the seahorse Hippocampus guttulatus inhabiting coastal waters of Galicia (north-western Iberian Peninsula) was assessed for three populations and 2 years using stable isotope mixing models. The Bayesian mixing model (MixSIAR) estimated the relative contributions of the dietary sources to the seahorse diet and revealed that Caprellidea were the primary source, followed by Gammaridea and Caridea. Mysidae and Annelida represented the less dominant prey. This prey preference can be explained by the foraging behaviour of seahorses. Different contributions of Gammaridea and Caridea to the diet were found among sites, indicating different habitat characteristics and hence different habitat use by seahorses within each site. In addition, differences were encountered among sexes. Caprellidea was the dominant prey for females, whereas Gammaridea was the dominant prey for males. The findings of the present study will contribute to the knowledge of feeding patterns of H. guttulatus, providing relevant data for conservation of this endangered species.

scholarly journals Monitoring and conservation of the rare orchid Didimoplexis verrucosa in the face of change

Bothalia ◽  
2021 ◽  
Vol 51 (2) ◽  
Author(s):  
T.H.C. Mostert ◽  
R.E. Mostert
Keyword(s):  
Conservation Status ◽  
Management Strategies ◽  
Population Monitoring ◽  
Environmental Indicators ◽  
Habitat Characteristics ◽  
Similar Degree ◽  
Suitable Habitat ◽  
Individual Plant ◽  
Accurate Identification ◽  
Term Survival

Abstract Background: Didymoplexis verrucosa is a cryptic leafless saprophytic ground orchid (~70 mm tall) growing on the coastal forest floors of southern Zululand and classified as Vulnerable (D2). As part of a population monitoring programme, 960 man-hours of species specific searching over five consecutive flowering seasons were conducted, yielding only one individual plant. Objective: The aim of this study was to increase detection rate by developing a profile of environmental indicators for the accurate identification of suitable habitat. Methods: A detailed description of suitable habitat was compiled based on the Braun-Blanquet approach. Results: The results showed that key attributes shared by localities include similar topographic position in the landscape, hydrology, soils, vegetation composition and structure, forest age, leaf-litter composition of the forest floor, the co-occurrence of Isoglossa woodii, and a similar degree of protection from sunlight, wind and desiccation. Significance of the findings: This profile of essential habitat characteristics can be used as a surrogate in the absence of actual locality data when identifying target conservation areas and compiling management strategies for this very cryptic species. A by-product of this habitat analysis was the discovery of a long list of impacts on the long term survival of D. verrucosa. The combination of these stochastic and deterministic events will drive habitat change at rates beyond the species’ ability to adapt. Managing these variables forms the crux of its successful conservation. A conservation status revision, based on the formal IUCN criteria, indicate that D. verrucosa should be reclassified as Critically Endangered Category B2a and D.  

Gut content and stable isotope analysis of tadpoles in floodplain wetlands

2018 ◽  
Vol 66 (4) ◽  
pp. 261 ◽  
Author(s):  
J. F. Ocock ◽  
K. J. Brandis ◽  
B. J. Wolfenden ◽  
K. M. Jenkins ◽  
S. Wassens
Keyword(s):  
Stable Isotope ◽  
Stable Isotope Analysis ◽  
Management Strategies ◽  
Isotope Analysis ◽  
Food Sources ◽  
Gut Contents ◽  
Floodplain Wetlands ◽  
Gut Content ◽  
Larval Amphibians ◽  
Aquatic Food

Larval amphibians (tadpoles) are an important link in aquatic food webs, as they can be highly abundant consumers and prey for a wide variety of predators. Most tadpoles are considered omnivores, predominately grazing on algae, detritus and macrophytes, though recent work has identified greater plasticity and breadth in diet than previously considered. We used gut content and stable isotope analysis (SIA) in a baseline study to determine the important dietary items (ingested material) and food sources (assimilated material) for tadpoles of two abundant generalist frog species in regulated floodplain wetlands of the Murrumbidgee River, south-east Australia. We identified a wide variety of dietary items in the gut contents, including whole microcrustaceans, filamentous algae and macrophytes. The composition of several ingested food items was correlated with their availability in each wetland. However, SIA identified biofilm as the food source most consistently assimilated across several wetlands, though microcrustaceans and algae contributed when abundant. Biofilm is likely the most important basal food item for tadpoles in floodplain wetlands because it is ubiquitous and has a high nutritional quality. Identifying important food sources is a crucial step towards developing management strategies for promoting tadpole recruitment in regulated wetlands.

scholarly journals Are Bumblebees Relevant Models for Understanding Wild Bee Decline?

2021 ◽  
Vol 2 ◽  
Author(s):  
Guillaume Ghisbain
Keyword(s):  
Environmental Changes ◽  
Conservation Status ◽  
Diet Breadth ◽  
Activity Period ◽  
Population Declines ◽  
Wild Bees ◽  
Wild Bee ◽  
Conservation Actions ◽  
Level Of Understanding ◽  
Bee Decline

The unsustainable use of ecosystems by human societies has put global biodiversity in peril. Bees are, in this context, a popular example of a highly diversified group of pollinators whose collapse is a major concern given the invaluable ecosystem services they provide. Amongst them, bumblebees (Bombus) have increasingly drawn the attention of scientists due to their dramatic population declines globally. This regression has converted them into popular conservation entities, making them the second most studied group of bees worldwide. However, in addition to have become relevant models in the fields of ecology, evolution and biogeography, bumblebees have also been used as models for studying wild bee decline and conservation worldwide. Integrating evidence from the comparative ecology and resilience of bumblebees and wild bees, I discuss the relevance of using Bombus as radars for wild bee decline worldwide. Responses of bumblebees to environmental changes are generally not comparable with those of wild bees because of their relatively long activity period, their inherent sensitivity to high temperatures, their relatively generalist diet breadth and many aspects arising from their eusocial behavior. Moreover, important differences in the available historical data between bumblebees and other bees make comparisons of conservation status even more arduous. Overall, these results reinforce the need for conservation actions that consider a higher level of understanding of ecological diversity in wild bees, highlight the need for an updated and more extensive sampling of these organisms, and emphasize that more caution is required when extrapolating trends from model species.

scholarly journals δ13C and δ18O Stable Isotope Analysis Applied to Detect Technological Variations and Weathering Processes of Ancient Lime and Hydraulic Mortars

Geosciences ◽  
2018 ◽  
Vol 8 (9) ◽  
pp. 339 ◽  
Author(s):  
Elissavet Dotsika ◽  
Dafni Kyropoulou ◽  
Vassilios Christaras ◽  
Georgios Diamantopoulos
Keyword(s):  
Stable Isotope ◽  
Stable Isotope Analysis ◽  
Isotope Analysis ◽  
Primary Source ◽  
Core Material ◽  
Weathering Processes ◽  
Lime Mortars ◽  
Primary Water ◽  
Carbonate Matrix ◽  
Δ13c And Δ18o

Samples of mortars were collected from lime and hydraulic mortars affected by environmental degradation. A total of 63 samples were obtained from Hellenistic, Late Roman and Byzantine historic constructions located at Kavala, Drama and Makrygialos in North Greece. Samples were collected in sections from the surface up to 6 cm deep using a drill-core material. The first sample was collected from the external layer, while the internal samples were collected each 1cm beeper from the previous, in order to monitor the moisture ingress. Isotopic data will make it possible to create an ideal Hellenistic and Byzantine mortar layer and to provide weathering gradients. The isotopic values comprise a range of δ13C and δ18O values from −17.1‰ to 1.2‰ and −25.9‰ to −2‰, respectively. The weathering process of Hellenistic and Byzantine are expressed, by the regression lines δ18Ocalcite matrix = 0.6 × δ13Ccalcite matrix − 1.9 and δ18Ocalcite matrix = 0.6 × δ13Ccalcite matrix − 2.0 for hydraulic and Lime mortars respectively. Pronounced isotopic shift to heavy or light δ13C and δ18O in the carbonate matrix was attributed to the primary source of CO2 (atmospheric versus biogenic) and H2O (evaporation of local primary water), in residual limestone and in secondary processes such as recrystallization of calcite with pore water and salts attack. Exogenic processes related to biological growth are responsible for further alterations of δ18O and δ13C in lime mortars. This study indicated that stable isotope analysis is an excellent tool to fingerprint the origin of carbonate, the environmental setting conditions of mortar, origin of CO2 and water during calcite formation and to determine the weathering depth and the potential secondary degradation mechanisms.

scholarly journals Cold-blooded indifference: a case study of the worsening status of threatened reptiles from Victoria, Australia

2015 ◽  
Vol 21 (1) ◽  
pp. 15 ◽  
Author(s):  
Nick Clemann
Keyword(s):  
Habitat Loss ◽  
Conservation Status ◽  
Management Strategies ◽  
Single Species ◽  
Mitigation Strategies ◽  
Terrestrial Vertebrate ◽  
Australian State ◽  
The World ◽  
Conservation Actions ◽  
History Of

For the first time in the history of life, a biodiversity extinction crisis is being driven by a single species – humans. Humans also have unprecedented control over both the threats and conservation actions that influence this crisis. When prioritising conservation actions, innate human bias often favours endothermic vertebrates over other fauna. Reptiles are the least popular terrestrial vertebrate class, and consequently are particularly disadvantaged in terms of being listed as threatened and receiving conservation management. Despite 30 years of formally evaluating and listing threatened vertebrates in the Australian State of Victoria, there is a strong worsening trend in the conservation status of all faunal groups. The deteriorating status of Victorian reptiles mirrors worrying documented trends in reptile conservation status around the world. I review the history of listing threatened reptiles in Victoria, detail worsening trends in their conservation status, and suggest that, as in other parts of the world, the threats common to most listed taxa are climate change, habitat loss and degradation, and elevated rates of predation by exotic predators. I also identify poor advice and planning as a considerable threat to Victorian reptiles; this threat is rarely reported, but may be more pervasive than currently recognised. I argue that what is needed for most reptiles to have the greatest chance of persisting in the long term is prevention of habitat loss and degradation, research to underpin listing and management, improved policy so that unproven management strategies are not sanctioned, and vetting of consultant’s reports so that unproven ‘mitigation’ strategies and inadequate preimpact surveys do not mask the true cost of loss and degradation of habitat.

Influence of environmental changes in the north-western Atlantic Ocean on a parasite, Echinorhynchus gadi (Acanthocephala) of Atlantic cod (Gadus morhua) occurring off coastal Labrador, Canada

2008 ◽  
Vol 82 (3) ◽  
pp. 203-209 ◽  
Author(s):  
R.A. Khan
Keyword(s):  
North Atlantic ◽  
Marine Mammals ◽  
Gadus Morhua ◽  
Small Schools ◽  
Environmental Changes ◽  
Atlantic Cod ◽  
Primary Source ◽  
Western Atlantic ◽  
The North ◽  
North Western

AbstractA study was conducted to determine the influence of environmental change on an endoparasite, Echinorhynchus gadi (Acanthocephala) of Atlantic cod (Gadus morhua) over a 30-year period off the coast of Labrador in the north-western Atlantic, North Atlantic Fisheries Organization subareas 2J–3K. Cod, once an abundant fish species that had been commercially exploited for many decades, declined precipitously during the mid-1980s onwards. This decline was attributed to climatic changes that affected the entire food chain from zooplankton to fish, sea birds and marine mammals. A monitoring programme was introduced, sampling cod by otter trawling using research vessels. The fish, after capture, were frozen at − 20°C, subsequently thawed and the digestive tract removed and examined for the parasite in 2006. Data from samples taken in 1976, 1980–81, 1986, 1990, 2000 and 2003 were compared statistically with those collected in 2006. The results indicate a decline in the prevalence and mean abundance of E. gadi in 1986 with a minimum in 2000 but increasing gradually in 2003 and 2006. These changes were coincident initially with a decline of oceanic temperature and the entire food web, including capelin (Mallotus villosus), a preferred prey of cod and primary source of E. gadi. The increase in prevalence and mean abundance of the parasite in 2006 were associated with an increase of oceanic temperature and the return of small schools of capelin to offshore areas. Cod older than 4 years harboured a greater abundance of E. gadi than younger fish, while no difference was observed between the sexes. The results suggest that the abundance of E. gadi can be useful as a bioindicator of environmental changes in the north-western Atlantic.

Stable isotope analysis as a tool for elasmobranch conservation research: a primer for non-specialists

2012 ◽  
Vol 63 (7) ◽  
pp. 635 ◽  
Author(s):  
D. S. Shiffman ◽  
A. J. Gallagher ◽  
M. D. Boyle ◽  
C. M. Hammerschlag-Peyer ◽  
N. Hammerschlag
Keyword(s):  
Stable Isotope ◽  
Stable Isotope Analysis ◽  
Anthropogenic Impacts ◽  
Management Strategies ◽  
Isotope Analysis ◽  
Cost Effective ◽  
Diet Breadth ◽  
Global Scale ◽  
Population Declines ◽  
Conservation And Management

Many elasmobranch species are undergoing population declines on a global scale; however, implementation of effective conservation and management strategies is hindered, to a large extent, by a lack of sufficient data on diet, life history and behaviour. This work is a primer of how stable isotope analysis can be used as a cost-effective, relatively simple tool for examining resource use patterns (e.g. diet, habitat) and generating relevant data in support of science-based elasmobranch conservation and management. Specifically, isotopes can resolve the feeding niches of elasmobranchs, detect ontogenetic trophic shifts and calculate relative diet breadth of different species. Stable isotope analysis can also be employed to investigate the extent of anthropogenic impacts on diet or to infer the source of toxins affecting elasmobranchs. Additionally, this tool can be used to study migration patterns and habitat usage. Depending on the tissue analysed, this technique can also be non-lethal and minimally invasive. The limitations of stable isotope analysis are discussed, and recommendations for future work are presented.

scholarly journals Recent Progresses in Stable Isotope Analysis of Cellulose Extracted from Tree Rings

Plants ◽  
2021 ◽  
Vol 10 (12) ◽  
pp. 2743
Author(s):  
Silviu-Laurentiu Badea ◽  
Oana Romina Botoran ◽  
Roxana Elena Ionete
Keyword(s):  
Stable Isotope ◽  
Hydrogen Isotope ◽  
Environmental Changes ◽  
Isotope Analysis ◽  
Isotope Ratio Mass Spectrometry ◽  
Hydrogen Atoms ◽  
Surrounding Water ◽  
Analytical Tools ◽  
Technical Sample

In this work, the challenges and progression in stable isotope investigation, from the analytical tools and technical sample preparation procedures to the dendroclimatological experiments, were reviewed in terms of their use to assess tree physiological responses to environmental changes. Since the isotope signature of whole wood is not always a reliable tool in studying the climate changes, cellulose is often preferred as the study material in paleoclimatic studies. Nevertheless, the isotope analysis of cellulose is challenging due to the difficulty to remove the other wood components (extractives, lignin, pectin, and hemicelluloses). Additionally, in the case of hydrogen isotope analysis, about 30% of the hydrogen atoms of cellulose are exchanged with the surrounding water, which complicates the isotope analysis. In recent years, more automated isotope analysis methods were developed based on high temperature pyrolysis of cellulose, followed by the chromatographic separation of H2 from CO and by their individual isotope analysis using isotope ratio mass spectrometry. When used to investigate climate factors, the combined isotope analysis δ13C and δ18O appears to be the most promising isotope tool. In contrast, the role of δ2H values is yet to be elucidated, together with the development of new methods for hydrogen isotope analysis.

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