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- Brogt, Erik, et al.
(författare)
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Using Institutional Research Data on Tertiary Performance to Inform Departmental Advice to Secondary Students
- 2011
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Ingår i: Australasian Association for Institutional Research (AAIR) Journal. - 1443-2110. ; 16:2, s. 26-41
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Tidskriftsartikel (refereegranskat)abstract
- This article examines the use of institutional research data on tertiary academic success of students in the first-year Biology program at the University of Canterbury in relation to their secondary school performance in English, Mathematics with Statistics, Biology and Chemistry. This study was commissioned by the School of Biological Sciences to examine the validity of the advice they gave to secondary students considering studying biology at university and was carried out as a joint venture between institutional researchers and departmental academics. We found that students with higher overall first-year university biology performance were more likely to also have taken Chemistry at secondary school. Controlling for overall performance, students taking both Chemistry and Biology as domains for the New Zealand University Entrance qualification (UE) did significantly better in two out of three first-year biology courses than those who had taken only one or neither subject as a domain. The extent of the advantage depended on the type of course; being greatest in the biochemistry-related course and least in ecology-related. We concluded that the advice the School of Biological Sciences had been giving students in secondary school as to the best preparation for (first-year) university studies in biology (emphasising the need to take both the subjects of Biology and Chemistry) was consistent with the institutional performance data of first-year students at university.
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| 2. |
- McIntosh, Angus R., et al.
(författare)
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The impact of trout on galaxiid fishes in New Zealand
- 2010
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Ingår i: New Zealand Journal of Ecology. - 0110-6465. ; 34:1, s. 195-206
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Tidskriftsartikel (refereegranskat)abstract
- Compared with the effect of invaders on the native terrestrial fauna of New Zealand, interactions between native fishes and introduced trout (sports fish in the genera Salmo, Oncorhynchus and Salvelinus) are less well known and there have been fewer efforts to remedy their effects. Trout have caused widespread reductions in the distribution and abundance of native galaxiid fishes, a family dominated by threatened species. The effects have been most severe on non-diadromous species (those lacking a marine migratory stage), which are commonly eliminated from streams by trout. Galaxiid populations in lakes, and those with migratory 'whitebait' stages, have also been affected, but the extent of the impacts are less understood. The mechanisms controlling negative interactions between trout and native fish, and how the environment modifies those interactions, will be important for future management. Experiments and field comparisons indicate size-specific predation by trout is the main driver of negative interactions. Large trout (> 150 mm long) do the greatest damage and small galaxiids (those with adult sizes < 150 mm long) are the most at risk. The fry stage of non-diadromous galaxiids is particularly vulnerable. Despite galaxiid fry production in some trout-invaded reaches, often no fry survive making them population 'sinks' that must be sustained by adult dispersal. Trout are also associated with changes in galaxiid behaviour and alterations to stream benthic communities. However, effects on galaxiid growth and fecundity have been little studied. Recent work also indicates that habitat conditions, especially floods, low flows and natural acidity, can mediate trout-galaxiid interactions. We argue that managers should be more proactive in their response to the plight of galaxiids, and we identify avenues of research that will benefit native fish conservation activities in the future.
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| 5. |
- Shumilova, Oleksandra, et al.
(författare)
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Simulating rewetting events in intermittent rivers and ephemeral streams : A global analysis of leached nutrients and organic matter
- 2019
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Ingår i: Global Change Biology. - : WILEY. - 1354-1013 .- 1365-2486. ; 25:5, s. 1591-1611
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Tidskriftsartikel (refereegranskat)abstract
- Climate change and human pressures are changing the global distribution and the extent of intermittent rivers and ephemeral streams (IRES), which comprise half of the global river network area. IRES are characterized by periods of flow cessation, during which channel substrates accumulate and undergo physico-chemical changes (preconditioning), and periods of flow resumption, when these substrates are rewetted and release pulses of dissolved nutrients and organic matter (OM). However, there are no estimates of the amounts and quality of leached substances, nor is there information on the underlying environmental constraints operating at the global scale. We experimentally simulated, under standard laboratory conditions, rewetting of leaves, riverbed sediments, and epilithic biofilms collected during the dry phase across 205 IRES from five major climate zones. We determined the amounts and qualitative characteristics of the leached nutrients and OM, and estimated their areal fluxes from riverbeds. In addition, we evaluated the variance in leachate characteristics in relation to selected environmental variables and substrate characteristics. We found that sediments, due to their large quantities within riverbeds, contribute most to the overall flux of dissolved substances during rewetting events (56%-98%), and that flux rates distinctly differ among climate zones. Dissolved organic carbon, phenolics, and nitrate contributed most to the areal fluxes. The largest amounts of leached substances were found in the continental climate zone, coinciding with the lowest potential bioavailability of the leached OM. The opposite pattern was found in the arid zone. Environmental variables expected to be modified under climate change (i.e. potential evapotranspiration, aridity, dry period duration, land use) were correlated with the amount of leached substances, with the strongest relationship found for sediments. These results show that the role of IRES should be accounted for in global biogeochemical cycles, especially because prevalence of IRES will increase due to increasing severity of drying events.
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