title: eDNA is a useful environmental monitoring tool for assessing stream ecological health

authors: Suren, Alastair

abstract: Environmental DNA (eDNA) is increasingly used in biodiversity assessments, but there remain uncertainties regarding its congruence with data based on traditional approaches involving habitat sampling and morphological‐based taxonomy. Using eDNA for biomonitoring has several advantages, including improved processing efficiencies and precision of taxonomic identification. In contrast, traditional biomonitoring is time‐consuming and expensive, often limiting the number of sites monitored. Establishing that eDNA‐derived metrics are congruent with their traditional equivalents on a national scale would support its wider use in biomonitoring. Our study compared ecosystem health assessments made by traditional biomonitoring techniques to those using eDNA from 53 sites throughout Aotearoa New Zealand. Because eDNA sampling was not done concurrently with benthic sampling at most sites, we used the average community composition at each site based on previous sampling occasions. We also allocated species identified by eDNA to the traditional level of identification to allow comparisons with eDNA data identified to broader taxonomic groups. We assessed similarities between the three datasets and found a high degree of correlation and convergence between biotic indices calculated from the different methods. eDNA did, however, appear to under‐represent some taxa, reflecting challenges in matching barcodes with an often‐incomplete sequence library. eDNA data did not always perform better in terms of showing the effects of land use on invertebrate community composition, but all datasets produced similar patterns. Multivariate analyses (redundancy analysis and variation partitioning) identified congruent relationships between environmental and spatial variables with the invertebrate community structure described by the three methods. eDNA data replicated the environmental responses and showed the same overall patterns in community composition as the traditionally collected data. We suggest that eDNA biomonitoring can complement traditional methods, and will perform at least as well as traditional data at detecting patterns in invertebrate community composition and ecosystem health at a national scale.

text: eDNA is a useful environmental monitoring tool for assessing stream ecological health Environmental DNA (eDNA) is increasingly used in biodiversity assessments, but there remain uncertainties regarding its congruence with data based on traditional approaches involving habitat sampling and morphological‐based taxonomy. Using eDNA for biomonitoring has several advantages, including improved processing efficiencies and precision of taxonomic identification. In contrast, traditional biomonitoring is time‐consuming and expensive, often limiting the number of sites monitored. Establishing that eDNA‐derived metrics are congruent with their traditional equivalents on a national scale would support its wider use in biomonitoring. Our study compared ecosystem health assessments made by traditional biomonitoring techniques to those using eDNA from 53 sites throughout Aotearoa New Zealand. Because eDNA sampling was not done concurrently with benthic sampling at most sites, we used the average community composition at each site based on previous sampling occasions. We also allocated species identified by eDNA to the traditional level of identification to allow comparisons with eDNA data identified to broader taxonomic groups. We assessed similarities between the three datasets and found a high degree of correlation and convergence between biotic indices calculated from the different methods. eDNA did, however, appear to under‐represent some taxa, reflecting challenges in matching barcodes with an often‐incomplete sequence library. eDNA data did not always perform better in terms of showing the effects of land use on invertebrate community composition, but all datasets produced similar patterns. Multivariate analyses (redundancy analysis and variation partitioning) identified congruent relationships between environmental and spatial variables with the invertebrate community structure described by the three methods. eDNA data replicated the environmental responses and showed the same overall patterns in community composition as the traditionally collected data. We suggest that eDNA biomonitoring can complement traditional methods, and will perform at least as well as traditional data at detecting patterns in invertebrate community composition and ecosystem health at a national scale.

year: 2024-07

title: Mapping the value chain of imported shellfish in China

authors: Wang, Ou

subjects: Science & Technology

abstract: This study explores the value chain structure and chain activities of the imported shellfish industry in China. Data were collected from face-to-face semi-structured interviews in Guangzhou (n = 30) and Shanghai (n = 23) and a face-to-face survey in Shanghai (n = 71). Data analysis employed both content and descriptive analyses. Results show that the value chain is composed of several important members including foreign exporters, Chinese importers, wholesalers, resellers and clearance companies. Business partnership is the main channel by which marketing information is gained by chain members. Relationships are quite stable among the chain members, with quality, price and credit items being the most important factors that influence chain relationships. It seems that imported shellfish from some developed countries (e.g. Canadian and U.S. lobsters) have reached a market saturation in China's first-tier cities (e.g. Guangzhou and Shanghai) and relevant chain members face fierce competition. E-commerce is still not mature enough as a tool for the marketing development of imported shellfish in China.

text: Mapping the value chain of imported shellfish in China This study explores the value chain structure and chain activities of the imported shellfish industry in China. Data were collected from face-to-face semi-structured interviews in Guangzhou (n = 30) and Shanghai (n = 23) and a face-to-face survey in Shanghai (n = 71). Data analysis employed both content and descriptive analyses. Results show that the value chain is composed of several important members including foreign exporters, Chinese importers, wholesalers, resellers and clearance companies. Business partnership is the main channel by which marketing information is gained by chain members. Relationships are quite stable among the chain members, with quality, price and credit items being the most important factors that influence chain relationships. It seems that imported shellfish from some developed countries (e.g. Canadian and U.S. lobsters) have reached a market saturation in China's first-tier cities (e.g. Guangzhou and Shanghai) and relevant chain members face fierce competition. E-commerce is still not mature enough as a tool for the marketing development of imported shellfish in China.

year: 2019

title: Maori preservice primary teachers’ responses to mathematics investigations

authors: Hāwera, Ngārewa

subjects: mathematics

abstract: There has been concern for some years about the low mathematics achievement of Maori students in New Zealand. This case study reports on the responses of 18 Maori preservice teachers to investigative approaches to learning mathematics during their compulsory Year 1 mathematics education course, as a possible aid towards helping improve the achievement level of Maori in mathematics.

text: Maori preservice primary teachers’ responses to mathematics investigations There has been concern for some years about the low mathematics achievement of Maori students in New Zealand. This case study reports on the responses of 18 Maori preservice teachers to investigative approaches to learning mathematics during their compulsory Year 1 mathematics education course, as a possible aid towards helping improve the achievement level of Maori in mathematics.

year: 2006