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Ökologie

Die Stabilisotopenanalyse einer Vielzahl von Materialien im Bereich der Ökologie erlaubt es Forschern, Informationen zu gewinnen, die mit anderen analytischen Methoden nicht erzielt werden können. Stabile Isotope werden von Ökologen häufig als Tracer in biologischen Systemen eingesetzt, um Elementkreisläufe in einem Ökosystem nachzuvollziehen. Variationen in der Isotopensignatur in unterschiedlichen geographischen Regionen erlauben es, Isotopen als Tracer für Migration zu nutzen, während mit Hilfe des Prinzips der Isotopenfraktionierung biogeochemische Prozesse in einer solchen Detailgenauikgeit analysiert werden können, die von der Betrachtung der Elementzusammensetzung alleine nicht erreicht werden kann.

So können z.B. Kohlenstoffisotope genutzt werden, um die Primärenergiequelle in einem Ökosystem zu bestimmen, wohingegen Stickstoffisotope nützlich sind, um die trophische Ebene eines Organismus zu identifizieren. Schwefelisotope können benthische Produzenten von pelagischen unterscheiden, ebenso wie Sumpfpflanzen von Phytoplanktonproduzenten.

Die Entwicklung unseres Verständnisses dieser immanenten Beziehungen zwischen lebenden Organismen und ihrer Umgebung durch die Stabilisotopenanalyse unterstützt unseren sorgfältigen Umgang mit der natürlichen Welt um zu gewährleisten, dass künftige Generationen die gleichen Wunder erleben wie wir heute.

Publikationen zum Thema Ökologie mit unseren Geräten

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155 Ergebnisse:

Applicability of Perinereis aibuhitensis Grube for fish waste removal from fish cages in Sanggou Bay, P. R. China
Journal of Ocean University of China (2016)
Jinghui Fang, Zengjie Jiang, Henrice M. Jansen, Fawen Hu, Jianguang Fang, Yi Liu, Yaping Gao, Meirong Du

The present study investigated the applicability of integrated polychaete-fish culture for fish waste removal to offset negative impact induced by organic benthic enrichment. A field study demonstrated that deposition rate was significantly higher underneath the fish farm than that in control area. The material settling under the farm was characterized by a high amount of fish feces (45%) and uneaten feed (27%). Both feeding rate (FR) and apparent digestibility rate (ADR) increased with decreasing body weight, as was indicated by significantly a higher rate observed for the groups containing smaller individuals in a lab study. The nutrient in fresh deposited material (De) was higher than that in sediments collected under the farm (Se), resulting in lower feces production but higher apparent digestibility rate for the De group as feeding rate was similar. Consequently, higher nutrient removal efficiency was observed in the De group. A mass balance approach indicated that approximately 400–500 individuals m−2 is required for removing all waste materials deposited underneath the fish farm, whereas abundance can be lower (about 300–350 individuals m−2) when only the fish waste needs to be removed. The results showed that a significant amount of waste had been accumulated in the fish cages in Sanggou Bay. The integration of fish with P. aibuhitensis seems promising for preventing organic pollution in the sediment and therefore is an effective strategy for mitigating negative effect of fish farms. Thus such integration can become a new IMTA (integrated multi-trophic aquaculture) model in Sanggou Bay.
Schlagworte: carbon , nitrogen , ecol , ocea , elem

Stable isotopes predict reproductive performance of European starlings breeding in anthropogenic environments
Ecosphere (2016)
Elizabeth Yohannes, Helga Gwinner, Raymond W. Lee, Hubert Schwabl

Understanding reproductive performance in ecologically impoverished vs. more sustained anthropogenic habitats is critical to assess population health status and to develop land use and conservation management strategies. We compared resource-based maternal effects, reproductive performance, and offspring quality in a model migratory passerine bird, the European starling (Sturnus vulgaris). We assessed female condition, quantity of egg constituents, quality of diet consumed during egg formation, and nestling growth and survival in two habitats: cultivated farmland and meadows. Egg, albumin, and shell mass were greater at the meadow site, while yolk mass did not differ significantly between sites; albumin mass most strongly predicted egg mass. Stable isotope enrichment (δ15N and δ13C) in yolk but not albumin suggests a broader range of diet for yolk formation at the meadow site but could also reflect different hydric conditions between sites. δ13C and δ15N enrichment did not predict yolk, albumin, or egg mass. Concentration of yolk testosterone was higher at the meadow site and correlated with δ13C enrichment in yolk. Nestling survival was higher in the meadow than in the farmland site and corresponded to egg mass and δ13C enrichment in lipid-free yolk. Surviving nestlings were larger in the meadow than in the farmland site. Results indicate that agricultural practice influences reproductive output through resource-based maternal effects. The analyses of isotopic and biochemical composition of small samples of yolk and albumin may provide a minimally invasive tool to assess individual reproductive performance and predict impacts of habitat quality on population health.
Schlagworte: carbon , nitrogen , ecol , elem

Integrating genetic and stable isotope analyses to infer the population structure of the White-winged Snowfinch Montifringilla nivalis in Western Europe
Journal of Ornithology (2016)
Jaime Resano-Mayor, Ángel Fernández-Martín, Sergio Hernández-Gómez, Ignasi Toranzo, Antonio España, Juan Antonio Gil, Miguel de Gabriel, Isabel Roa-Álvarez, Eliseo Strinella, Keith A. Hobson, Gerald Heckel, Raphaël Arlettaz

The population structure and seasonal movements of alpine birds in Europe are still largely unknown. Species living in high mountains now face acute risks of habitat loss, range contractions and local extinction due to current and projected climate change. Therefore, a better understanding of the spatial structuring and exchange among populations of European mountain birds is important from both ecological and conservation points of view. The White-winged Snowfinch Montifringilla nivalis is one of the most characteristic passerines of alpine habitats in Europe. Despite the fact that its breeding nuclei are relatively well defined, we still know little about the species’ population structure and movements in Western Europe. By analysing two mitochondrial loci (cytochrome b and the control region) and stable isotopes of hydrogen (δ2H), we assessed to what extent breeding populations of White-winged Snowfinches in the Cantabrian Mountains (CM), the Pyrenees and the Alps, and also a wintering population in the Eastern Pyrenees, function as a metapopulation. We first show the phylogenetic relationships of the White-winged Snowfinch (Montifringilla nivalis subsp. nivalis) within the Snowfinch complex. When assessing the population structure in Western Europe, most mitochondrial haplotypes were present in all breeding populations, but one was only found in the CM where it predominated. The most widespread haplotypes at the breeding grounds were found in the majority of the wintering individuals, but none of them showed the haplotype specific to the CM. We did not find differences in δ2H for the primary feathers among breeding populations, but rectrices of individuals wintering in the Pyrenees had considerably lower δ2H values: isotopic analysis could thus be useful to assign wintering birds to their Alpine breeding grounds. Further studies combining ringing and the analyses of intrinsic markers are an essential step in better appraising the species’ metapopulation dynamics and guiding conservation.
Schlagworte: hydrogen , ecol , elem

Topography of the Andes Mountains shapes the wintering distribution of a migratory bird
Diversity and Distributions (2016)
Ana M. González-Prieto, Nicholas J. Bayly, Gabriel J. Colorado, Keith A. Hobson

Aim In birds, patterns of migratory connectivity are influenced by landscape structure experienced throughout the annual cycle. Assessing how landscape patterns drive the movements and distributions of migratory species is important for understanding the evolution of migration and determining conservation priorities. We determined migratory connectivity in the Canada Warbler (Cardellina canadensis), a declining Neotropical migratory bird, and evaluated the degree to which the Andean mountains influence winter population distribution in this montane forest specialist. Location Seven study regions across the Western, Central, and Eastern Andes of Colombia. Methods We inferred breeding and natal origins of Canada Warblers overwintering in Colombia by analysing stable hydrogen isotope values (δ2H) in feathers and assigning wintering populations to breeding origins using an established feather δ2H isoscape for North America. Results We found strong evidence for parallel migration between breeding and wintering sites, giving rise to moderately strong migratory connectivity between breeding and wintering regions. The model best explaining population distribution in the Colombian Andes implied that populations were most similar within basins or valleys. Such segregation is notable, given that basins are separated by less than 300 km on the wintering grounds, while breeding populations may be separated by more than 3000 km from east to west. Main conclusions Our results suggest that the high spine of each Andean cordillera acts to shape the winter distribution of individuals from different breeding populations. To our knowledge, this is the first demonstration that the topography of the Andean mountains can act to shape the winter distribution of populations of a migratory bird. The strength of migratory connectivity found in Canada Warblers may inhibit evolutionary responses to environmental change, and the more rapid population declines recorded in some eastern breeding populations may be related to habitat loss and local environmental conditions in the Eastern Andes, where individuals from these populations were more likely to overwinter.
Schlagworte: hydrogen , ecol , elem

Body size drives allochthony in food webs of tropical rivers
Oecologia (2016)
Timothy D. Jardine, Thomas S. Rayner, Neil E. Pettit, Dominic Valdez, Douglas P. Ward, Garry Lindner, Michael M. Douglas, Stuart E. Bunn

Food web subsidies from external sources (“allochthony”) can support rich biological diversity and high secondary and tertiary production in aquatic systems, even those with low rates of primary production. However, animals vary in their degree of dependence on these subsidies. We examined dietary sources for aquatic animals restricted to refugial habitats (waterholes) during the dry season in Australia’s wet–dry tropics, and show that allochthony is strongly size dependent. While small-bodied fishes and invertebrates derived a large proportion of their diet from autochthonous sources within the waterhole (phytoplankton, periphyton, or macrophytes), larger animals, including predatory fishes and crocodiles, demonstrated allochthony from seasonally inundated floodplains, coastal zones or the surrounding savanna. Autochthony declined roughly 10% for each order of magnitude increase in body size. The largest animals in the food web, estuarine crocodiles (Crocodylus porosus), derived ~80% of their diet from allochthonous sources. Allochthony enables crocodiles and large predatory fish to achieve high biomass, countering empirically derived expectations for negative density vs. body size relationships. These results highlight the strong degree of connectivity that exists between rivers and their floodplains in systems largely unaffected by river regulation or dams and levees, and how large iconic predators could be disproportionately affected by these human activities
Schlagworte: carbon , nitrogen , ecol , elem

Distribution and attachment characteristics of Sida crystallina (O.F. Müller, 1776) in lentic freshwater ecosystems of South Korea
Journal of Ecology and Environment (2016)
Jong-Yun Choi, Kwang-Seuk Jeong, Seong-Ki Kim, Se-Hwan Son, Gea-Jae Joo

Background Macrophytes are commonly utilised as habitat by epiphytic species; thus, complex macrophyte structures can support high diversities and abundances of epiphytic species. We tested the hypothesis that the presence of aquatic macrophytes is an important factor determining Sida crystallina (O.F. Müller, 1776) distribution. Results An ecological survey was conducted in 147 lentic freshwater bodies. S. crystallina was frequently observed, and its density was strongly associated with macrophyte abundance. S. crystallina was found on emergent plant species such as Phragmites australis and Paspalum distichum, attached to the stem surfaces by adhesive substances secreted by the nuchal organ. Thus, S. crystallina was more strongly attached to macrophytes than to other epiphytic cladoceran species. We found higher densities of S. crystallina in filtered water with increased macrophyte shaking effort (i.e. 10, 20, 40, or 80 times). S. crystallina attachment was not related to fish predation. Stable isotope analysis showed that S. crystallina utilises epiphytic organic matter (EOM) on macrophytes as a food source. Conclusions Consequently, S. crystallina seems to have a strong association with species-specific macrophyte biomass than with other cladoceran species, which may contribute to this species’ predominance in various freshwater ecosystems where macrophytes are abundant.
Schlagworte: carbon , nitrogen , ecol , elem

Using the stable isotope marker 13 C to study extrafloral nectar uptake by parasitoids under controlled conditions and in the field
Entomologia Experimentalis et Applicata (2016)
Anna Pollier, Simon Dosdat, Yann Tricault, Armin Bischoff, Manuel Plantegenest, Bruno Jaloux

Parasitic wasps are prominent natural enemies of crop pests. They usually feed on floral resources during the adult stage (nectar, pollen, or honeydew). Extrafloral nectar is an alternative source of sugar easily accessible to adult parasitoids. We developed an original method of nectar labelling based on the injection of labelled sugar solution into the plant stem in order to analyse the nectar uptake by parasitoids (cotton wick method). This method was used to artificially enrich extrafloral cornflower, Centaurea cyanus L. (Asteraceae), nectar with the stable isotope 13C. We analysed (1) the transfer of 13C from the sugar solution into extrafloral nectaries, (2) the uptake of labelled nectar by parasitoids under laboratory conditions, and (3) the ability of the method to discriminate, in an oilseed rape (Brassica napus L., Brassicaceae) field, between labelled parasitoids (i.e., those who have fed on labelled cornflowers located adjacent to the field) and unlabelled parasitoids to track parasitoid movements from the margin into the field. The extrafloral nectar of all test plants was 13C-labelled. Most (66%) of the parasitoids were identified as marked after 96 h of exposure to labelled plants in the laboratory. We could also detect labelled parasitoids inside the field, but the detection rate was only 1%. The experiments clearly demonstrate that the cotton wick method is appropriate to label extrafloral nectar and parasitoids feeding on this labelled nectar. Further research is needed on the amount of labelled extrafloral nectar required to obtain a sufficient marker level to track parasitoid movements in the field.
Schlagworte: carbon , ecol , elem

Species-specific accumulation of polybrominated diphenyl ethers (PBDEs) and other emerging flame retardants in several species of birds from Korea
Environmental Pollution (2016)
Xiangzi Jin, Sunggyu Lee, Yunsun Jeong, Jae-Pyoung Yu, Woon Kee Baek, Kyung-Hoon Shin, Kurunthachalam Kannan, Hyo-Bang Moon

Few studies have been conducted on the alternatives to legacy flame retardants in avian species worldwide. In this study, polybrominated diphenyl ethers (PBDEs) and alternative flame retardants such as novel brominated flame retardants (NBFRs) and dechlorane plus (DP) were determined in livers of 10 species of birds from Korea to elucidate species-specific accumulation, biological factors that affect accumulation, and bioaccumulation potentials of these contaminants. Among the emerging alternative flame retardants, the highest occurrence was found for bis(2-ethylhexyl)-3,4,5,6-tetrabromo-phthalate (BEHTBP), syn-DP, anti-DP, and decabromodiphenyl ethane (DBDPE). PBDE concentrations (median: 17.1 ng/g lipid wt) measured in our study were within the ranges reported in previous studies, while the concentrations of BEHTBP, BTBPE and DP were greater than those reported earlier. Residential predatory birds showed significantly greater concentrations of PBDEs and NBFRs than migratory predators and passerine birds. The concentrations of PBDEs, BEHTBP, and DP in residential predatory birds were significantly correlated with increasing stable nitrogen isotope ratio (δ15N), which indicated biomagnification potentials of these contaminants. Our results suggest that the concentrations and accumulation patterns of PBDEs, NBFRs, and DP depend on the feeding habits and migration patterns of avian species. This is the first report on the accumulation of emerging alternatives to PBDEs in birds from Korea.
Schlagworte: nitrogen , ecol , poll , elem

The feasibility of assessing the diets of minke whale (Balaenoptera acutorostrata) in the East Sea through fatty acid composition in blubber and stable isotopic ratio of skin
Ocean Science Journal (2016)
Ah-Ra Ko, Se-Jong Ju, Seok-Gwan Choi, Kyung-Hoon Shin

To track the diet of minke whale (Balaenoptera acutorostrata) in the East Sea (Japan Sea), a conjoint analysis of fatty acids and C and N stable isotopes was performed on blubber and skin from the whale and its potential prey. The total lipid content in the blubber of minke whales ranged from 37.9% to 82.7% of wet mass (mean ± SD, 63.1 ± 17.2%), with triacylglycerols being the dominant lipids (96.9%–99.2% of total lipids). The lipid and fatty acid (FA) contents were systematically stratified throughout the depth of the blubber layers; contents of the dominant monounsaturated FAs (MUFAs), including 18:1ω9 and 16:1ω7, increased from the innermost layer to the outermost layer, whereas contents of saturated FAs (SFAs) and polyunsaturated FAs (PUFAs) were higher in the innermost layer than in the outermost layer. This stratification is related to the different physiological roles of the blubber layers; e.g., thermoregulation, streaming, and buoyancy. A comparison of the FA compositions of the innermost layer of minke whales with those of potential prey indicates that FA compositions in the whales are similar to those of Pacific herring. In addition, stable isotope ratios (δ13C and δ15N) suggest that minke whale and Pacific herring have the same or similar diets. Therefore, the diets of minke whale from the East Sea (Japan Sea) could be inferred from information on the diet of the Pacific herring, although FA compositions and stable isotope ratios for Pacific herring would not exactly reflect the whale’s diet. Although the very limited number of samples was used in this study, our preliminary findings are very promising to help understand the feeding ecology of minke whales in the East Sea (Japan Sea).
Schlagworte: carbon , nitrogen , ecol , elem

Behavior of Migratory Tree Bats in the Western Basin of Lake Erie Using Telemetry and Stable Isotope Analysis
Thesis (2015)
Shaylyn K Hatch

New technologies are allowing researchers to more accurately quantify migratory movement and stopover behavior for a variety of species, including bats. Better understanding of the spatial and temporal scale of migration can inform conservation decisions related to sensitivity of particular locations for migratory species, especially in the face of ongoing development and climate change. Improved quantification of movement corridors can lead to proactive strategies for conservation by prioritizing areas that facilitate movement. Using passive and active telemetry, we were able to identify movement patterns of long distance migrants from east to west along Lake Erie’s western basin and determine stopover duration for Lasiurus borealis and Lasiurus noctivagans (5.6 and 1 days respectively) during spring migration. Bats were more likely to move east to west along the shoreline of Lake Erie as opposed to flying long distances over open water. Departures of migratory bats were more likely to occur on nights with higher barometric pressure, higher dew point, and a lower wind differential (difference between wind gust and sustained wind speed). In addition, we used stable isotope analysis of bat fur to learn more about the ecology of bats captured in the western basin of Lake Erie. We determined that big brown, silver-haired, and red bats were isotopically distinct in carbon and nitrogen, while migrant and resident eastern red bats (as determined by telemetry) were not. This study adds to our knowledge of bat migration and should be useful for future decisions related to conservation and management of natural resources within the western basin of Lake Erie
Schlagworte: carbon , nitrogen , ecol , elem