2021 State of the Environment Report Marine Chapter – Expert Assessment – State and Trend – Trophic structures and relationships

Researchers: Bulman, Catherine (Author) ,  Emma Flukes (Point of contact) ,  Fulton, Beth (Author) ,  Fulton, Elizabeth (Author) ,  Hobday, Alistair (Author)

Brief description The Marine chapter of the 2021 State of the Environment (SoE) report incorporates multiple expert templates developed from streams of marine data. This metadata record describes the Expert Assessment "State and Trend of trophic structures and relationships". ***A PDF of the full Expert Assessment, including figures and tables (where provided) is downloadable in the "On-line Resources" section of this record as "EXPERT ASSESSMENT 2021 - Trophic structures and relationships"*** ---------------------------------------- DESCRIPTION OF COMMUNITY/PROCESS FOR EXPERT ASSESSMENT Trophic relationships indicate linkages between species in food webs – who eats who. Consumers in open-ocean pelagic food webs rely on plankton at their base (Griffiths et al.., 2010; Antoine et al., 2020); inshore, benthic food webs may also have a heavy reliance on plankton (Truong et al., 2017) but can also be based on macrophytes, detritus and many invertebrate prey species (Abrantes et al., 2015). Historically, our understanding of these relationships was based on dietary studies (particularly stomach content analysis), which were undertaken sporadically in space and time. More recently, DNA techniques have been applied to stomach contents to detect prey that might not be normally identified from visual analyses, thereby expanding the food web (Berry et al., 2015). These studies may span a large number of species or focus on a subset of interest. Thus, to assemble a food web for a region, and then to assess change, requires many years of sampling, often combining data from different studies. In contrast, diet studies of single species are relatively common, and may be observed through visual observations, imagery, stomach contents, or scat analysis. These studies can reveal geographic, interannual, or long-term change, and indicate wider ecosystem change (e.g. see examples based around little penguins and pinnipeds; Chiaradia et al., 2010; Kirkwood et al., 2008). DATA STREAM(S) USED IN EXPERT ASSESSMENT No raw data analyses were used in this assessment, instead it represents a synthesis of literature published in the last 5 years. ---------------------------------------- 2021 SOE ASSESSMENT SUMMARY [see attached Expert Assessment for full details] • 2021 • Assessment grade: Poor-good. Variable. Assessment trend: Unclear. Variable. Confidence grade: Adequate Confidence trend: Limited Comparability: Comparable • 2016 • Assessment grade: Poor-Good Assessment trend: Unclear Confidence grade: Adequate high quality evidence or high level of consensus Confidence trend: Adequate high quality evidence or high level of consensus Comparability: Grade and trend are comparable to the 2011 assessment • 2011 • Assessment grade: Good Assessment trend: Stable Confidence grade: Limited evidence or limited consensus Confidence trend: Limited evidence or limited consensus ---------------------------------------- CHANGES SINCE 2016 SOE ASSESSMENT Assessment is in line with what was found in 2016.

Lineage Statement: QUALITY OF DATA USED IN THE ASSESSMENT not supplied

Lineage

Notes Credit
Peer reviews of this assessment were provided by: Adriana Vergés (University of New South Wales)

162.42188,-7.20703 162.42188,-47.46094 102.65625,-47.46094 102.65625,-7.20703 162.42188,-7.20703

132.5390625,-27.333984375

text: westlimit=102.65625000000001; southlimit=-47.4609375; eastlimit=162.421875; northlimit=-7.207031249999999