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Publications

NIBIOs employees contribute to several hundred scientific articles and research reports every year. You can browse or search in our collection which contains references and links to these publications as well as other research and dissemination activities. The collection is continously updated with new and historical material.

2020

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Abstract

Purpose Sorption could be a way to concentrate nutrients in diluted waste streams to bring more nutrients back to agriculture. The aim of this work was to model the fate of sorbed NH4+ content in liquid waste streams by adding nitrogen (N) sorbed to a sorbent, zeolite, and study its effect on early growth and potential leaching losses. Methods A pot experiment with two soil types and wheat as test crop was conducted. Mineral N in soil was measured, and a leaching experiment performed. 15N labelled ammonium was sorbed to zeolite. The fertilizer effect was then compared to ammonium fertilizer applied the conventional way, with and without zeolite. Results Early uptake of sorbed ammonium was reduced by 56% compared to ammonium applied conventionally, and soil uptake compensated only very early. Nitrate concentration in leachates was reduced by 12% in sandy soil when N was applied sorbed to zeolite. However, leaching of water through the profile increased 71% when N was applied sorbed to zeolite, so that there was only a tendency to lower N losses when N was applied sorbed to zeolite. Conclusion Ammonium-N sorbed to zeolite is less plant available than conventionally applied N but may also be less prone to leaching losses.

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Abstract

Spatiotemporal variation in natural selection is expected, but difficult to estimate. Pollinator‐mediated selection on floral traits provides a good system for understanding and linking variation in selection to differences in ecological context. We studied pollinator‐mediated selection in five populations of Dalechampia scandens (Euphorbiaceae) in Costa Rica and Mexico. Using a nonlinear path‐analytical approach, we assessed several functional components of selection, and linked variation in pollinator‐mediated selection across time and space to variation in pollinator assemblages. After correcting for estimation error, we detected moderate variation in net selection on two out of four blossom traits. Both the opportunity for selection and the mean strength of selection decreased with increasing reliability of cross‐pollination. Selection for pollinator attraction was consistently positive and stronger on advertisement than reward traits. Selection on traits affecting pollen transfer from the pollinator to the stigmas was strong only when cross‐pollination was unreliable and there was a mismatch between pollinator and blossom size. These results illustrate how consideration of trait function and ecological context can facilitate both the detection and the causal understanding of spatiotemporal variation in natural selection.

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Abstract

Red-listed species are often used as target species in selection of sites for conservation. However, limitations to their use have been pointed out, and here we address the problem of expected high spatio-temporal dynamics of red-listed species. We used species data (vascular plants, bryophytes, macrolichens and polypore fungi) from two inventories 17 years apart to estimate temporal turnover of red-listed and non-red-listed species in two forest areas (147 and 195 ha) and of plots (0.25 ha) within each area. Furthermore, we investigated how turnover of species afected the rank order of plots regarding richness of red-listed species, using two diferent national Red List issues (1998 and 2015). In both study areas, temporal turnover was substantial, despite minor changes in the overall number of species. At plot level, temporal turnover in red-listed species was higher than in non-red-listed species, but similar to non-red-listed species of the same frequency of occurrence. Adding the efect of changing identities of species red-listed according to the two Red List issues, further increased the estimated spatio-temporal dynamics. Recorded spatio-temporal turnover also resulted in substantial changes in the rank order of plots regarding richness of red-listed species. Using rare red-listed species for site selection may therefore be accompanied by a higher loss of conservation efectiveness over time than for more common species, and particularly at fner scales. Red-listed species · Site selection · Spatio-temporal dynamics · Temporal turnover