The influence of diet on the distribution of nitrogen isotopes in animals was investigated by analyzing animals grown in the laboratory on diets of constant nitrogen isotopic composition. 
The isotopic composition of the nitrogen in an animal reflects the nitrogen isotopic composition of its diet. The δ^(15)N values of the whole bodies of animals are usually more positive than those of their diets. Different individuals of a species raised on the same diet can have significantly different δ^(15)N values. The variability of the relationship between the δ^(15)N values of animals and their diets is greater for different species raised on the same diet than for the same species raised on different diets. Different tissues of mice are also enriched in ^(15)N relative to the diet, with the difference between the δ^(15)N values of a tissue and the diet depending on both the kind of tissue and the diet involved. The δ^(15)N values of collagen and chitin, biochemical components that are often preserved in fossil animal remains, are also related to the δ^(15)N value of the diet. 
The dependence of the δ^(15)N values of whole animals and their tissues and biochemical components on the δ^(15)N value of diet indicates that the isotopic composition of animal nitrogen can be used to obtain information about an animal's diet if its potential food sources had different δ^(15)N values. The nitrogen isotopic method of dietary analysis probably can be used to estimate the relative use of legumes vs non-legumes or of aquatic vs terrestrial organisms as food sources for extant and fossil animals. However, the method probably will not be applicable in those modern ecosystems in which the use of chemical fertilizers has influenced the distribution of nitrogen isotopes in food sources. 
The isotopic method of dietary analysis was used to reconstruct changes in the diet of the human population that occupied the Tehuacan Valley of Mexico over a 7000 yr span. Variations in the δ^(15)C and δ^(15)N values of bone collagen suggest that C_4 and/or CAM plants (presumably mostly corn) and legumes (presumably mostly beans) were introduced into the diet much earlier than suggested by conventional archaeological analysis.

Influence of Diet On the Distribtion of Nitrogen Isotopes in Animals

This study describes and validates a new method for metagenomic biomarker discovery by way of class comparison, tests of biological consistency and effect size estimation. This addresses the challenge of finding organisms, genes, or pathways that consistently explain the differences between two or more microbial communities, which is a central problem to the study of metagenomics. We extensively validate our method on several microbiomes and a convenient online interface for the method is provided at http://huttenhower.sph.harvard.edu/lefse/.

Metagenomic biomarker discovery and explanation

The identification of the genetic structure of populations from multilocus genotype data has become a central component of modern population-genetic data analysis. Application of model-based clustering programs often entails a number of steps, in which the user considers different modelling assumptions, compares results across different predetermined values of the number of assumed clusters (a parameter typically denoted K), examines multiple independent runs for each fixed value of K, and distinguishes among runs belonging to substantially distinct clustering solutions. Here, we present CLUMPAK (Cluster Markov Packager Across K), a method that automates the postprocessing of results of model-based population structure analyses. For analysing multiple independent runs at a single K value, CLUMPAK identifies sets of highly similar runs, separating distinct groups of runs that represent distinct modes in the space of possible solutions. This procedure, which generates a consensus solution for each distinct mode, is performed by the use of a Markov clustering algorithm that relies on a similarity matrix between replicate runs, as computed by the software CLUMPP. Next, CLUMPAK identifies an optimal alignment of inferred clusters across different values of K, extending a similar approach implemented for a fixed K in CLUMPP and simplifying the comparison of clustering results across different K values. CLUMPAK incorporates additional features, such as implementations of methods for choosing K and comparing solutions obtained by different programs, models, or data subsets. CLUMPAK, available at http://clumpak.tau.ac.il, simplifies the use of model-based analyses of population structure in population genetics and molecular ecology.

/pdf/clumpak-a-program-for-identifying-clustering-modes-and-4ljqxgdc53.pdf

Clumpak: a program for identifying clustering modes and packaging population structure inferences across K

Generalized Linear Models (2nd ed.)

Twenty-four articles by biologists, ecologists, and other scientists represent a year's progress in the field. Among the topics addressed: the effects of introduced species, paleobiogeography, genetics and geographic structure, marine fisheries management, time as an ecological resource, genetic var

Annual Review of Ecology, Evolution and Systematics

The red panda (Ailurus fulgens) is an endangered species distributed in the Himalaya and Hengduan Mountains and extremely difficult to monitor because it is elusive, wary and nocturnal. However, recent advances in noninvasive genetics are allowing conservationists to indirectly estimate population size of this animal. Here, we present a pilot study of individual identification of wild red pandas using DNA extracted from faeces. A chain of optimal steps in noninvasive studies were used to maximize genotyping success and minimize error rate across sampling, selection of microsatellite loci, DNA extraction and amplification and data checking. As a result, 18 individual red pandas were identified successfully from 33 faecal samples collected in the field using nine red panda-specific microsatellite loci with a low probability of identity of 1.249 × 10−3 for full siblings. Multiple methods of tracking genotyping error showed that the faecal genetic profiles possessed very few genotyping errors, with an overall error rate of 1.12 × 10−5. Our findings demonstrate the feasibility and reliability of using faeces as an effective source of DNA for estimating and monitoring wild red panda populations.

Genotyping faeces of red pandas (Ailurus fulgens): implications for population estimation

Digital Noah’s Ark: last chance to save the endangered species

Understanding how population density relates to habitat underlies basic ecological theory and is pertinent to conservation issues. Chiru (Pantholops hodgsonii) are an endangered steppe-dwelling ungulate endemic to the Tibetan plateau. To prepare effective conservation and management strategies for this species, we require detailed knowledge of the relationship between group size and habitat conditions. We surveyed the Chang Tang region of Tibet and used data collected along vehicular line transects to record the presence and group size of chiru. Using ecological niche factor analysis, we inferred the ecological requirements of chiru in relation to a large number of topographic, vegetation, and anthropogenic variables. We used these analyses to estimate habitat suitability models and describe their optimum range. Areas favored by chiru had moderate grazing by domestic animals, gentle slopes, and villages present only at lower altitudes. Chiru showed a high level of specialization regarding the presence of villages and gentle slopes, and were negatively associated with areas of those easily accessed by people. We suggest new management measures for the long-term conservation of chiru. Specifically, we focus on the rehabilitation of natural plains for grazing by chiru, recognizing that conservation of large groups may require special efforts. For smaller groups and solitary chiru, the large tracts of unsuitable or marginal areas may expose them to different threats that could pose greater challenges for conservation management. © 2015 The Wildlife Society.

Habitat suitability for chiru (Pantholops hodgsonii): Implications for conservation management across the Tibetan region of Chang Tang

Abstract Marine biodiversity plays important roles in ocean ecosystem services and has substantial economic value. Species diversity, genetic diversity and phylogenetic diversity, which reflect the number, evolutionary potential and evolutionary history of species in ecosystem functioning, are three important dimensions of biodiversity. Marine-protected areas have been demonstrated as an effective area-based tool for protecting marine biodiversity, but only 2.8% of the ocean has been fully protected. It is urgent to identify global conservation priority areas and percentage of the ocean across multiple dimensions of biodiversity based on Post-2020 Global Biodiversity Framework. Here, we investigate the spatial distribution of marine genetic and phylogenetic diversity using 80 075 mitochondrial DNA barcode sequences from 4316 species and a newly constructed phylogenetic tree of 8166 species. We identify that the Central Indo-Pacific Ocean, Central Pacific Ocean and Western Indian Ocean harbor high levels of biodiversity across three dimensions of biodiversity, which could be designated as conservation priority areas. We also find that strategically protecting ∼22% of the ocean would allow us to reach the target of conserving ∼95% of currently known taxonomic, genetic and phylogenetic diversity. Our study provides insights into the spatial distribution pattern of multiple marine diversities and the findings would help to design comprehensive conservation schemes for global marine biodiversity.

https://academic.oup.com/nsr/advance-article-pdf/doi/10.1093/nsr/nwac241/46700536/nwac241.pdf

Yibo Hu

Papers

Genotyping faeces of red pandas (Ailurus fulgens): implications for population estimation

Digital Noah’s Ark: last chance to save the endangered species

Habitat suitability for chiru (Pantholops hodgsonii): Implications for conservation management across the Tibetan region of Chang Tang

Conservation priorities for global marine biodiversity across multiple dimensions

Patterns and effects of GC3 heterogeneity and parsimony informative sites on the phylogenetic tree of genes.