Forested buffers in agricultural landscapes : mitigation effects on stream–riparian meta-ecosystems

Stream–riparian meta-ecosystems are strongly connected through exchanges of energy, material and organisms. Land use can disrupt ecological connectivity by affecting community composition directly and/or indirectly by altering the instream and riparian habitats that support biological structure and function. Although forested riparian buffers are increasingly used as a management intervention, our understanding of their effects on the functioning of stream–riparian metaecosystems is limited. This study assessed patterns in the longitudinal and lateral profiles of streams in modified landscapes across Europe and Sweden using a pairedreach approach, with upstream unbuffered reaches lacking woody riparian vegetation and with downstream reaches having well-developed forested buffers. The presence of buffers was positively associated with stream ecological status as well as important attributes, which included instream shading and the provision of suitable habitats for instream and riparian communities, thus supporting more aquatic insects (especially EPT taxa). Emergence of aquatic insects is particularly important because they mediate reciprocal flows of subsidies into terrestrial systems. Results of fatty acid analysis and prey DNA from spiders further supported the importance of buffers in providing more aquatic-derived quality food (i.e. essential fatty acids) for riparian spiders. Findings presented in this thesis show that buffers contribute to the strengthening of cross-ecosystem connectivity and have the potential to affect a wide range of consumers in modified landscapes

Forested riparian buffers change the taxonomic and functional composition of stream invertebrate communities in agricultural catchments

Riparian zones form the interface between stream and terrestrial ecosystems and play a key role through their vegetation structure in determining stream biodiversity, ecosystem functioning and regulating human impacts, such as warming, nutrient enrichment and sedimentation. We assessed how differing riparian vegetation types influence the structural and functional composition (based on species traits) of stream invertebrate communities in agricultural catchments. We characterized riparian and stream habitat conditions and sampled stream invertebrate communities in 10 independent site pairs, each comprising one “unbuffered” reach lacking woody riparian vegetation and a second downstream reach with a woody riparian buffer. Forested riparian buffers were associated with greater shading, increased gravel content in stream substrates and faster flow velocities. We detected changes in invertebrate taxonomic composition in response to buffer presence, with an increase in sensitive Ephemeroptera, Plecoptera and Trichoptera (EPT) taxa and increases in key invertebrate species traits, including species with preference for gravel substrates and aerial active dispersal as adults. Riparian vegetation independently explained most variation in taxa composition, whereas riparian and instream habitat together explained most variation in functional composition. Our results highlight how changes in stream invertebrate trait distributions may indirectly reflect differences in riparian habitat, with implications for stream health and cross-ecosystem connectivity

Assessing the Benefits of Forested Riparian Zones: A Qualitative Index of Riparian Integrity Is Positively Associated with Ecological Status in European Streams

Developing a general, predictive understanding of ecological systems requires knowing how much structural and functional relationships can cross scales and contexts. Here, we introduce the CROSSLINK project that investigates the role of forested riparian buffers in modified European landscapes by measuring a wide range of ecosystem attributes in stream-riparian networks. CROSSLINK involves replicated field measurements in four case-study basins with varying levels of human development: Norway (Oslo Fjord), Sweden (Lake Malaren), Belgium (Zwalm River), and Romania (Arge River). Nested within these case-study basins include multiple, independent stream-site pairs with a forested riparian buffer and unbuffered section located upstream, as well as headwater and downstream sites to show cumulative land-use impacts. CROSSLINK applies existing and bespoke methods to describe habitat conditions, biodiversity, and ecosystem functioning in aquatic and terrestrial habitats. Here, we summarize the approaches used, detail protocols in supplementary materials, and explain how data is applied in an optimization framework to better manage tradeoffs in multifunctional landscapes. We then present results demonstrating the range of riparian conditions present in our case-study basins and how these environmental states influence stream ecological integrity with the commonly used macroinvertebrate Average Score Per Taxon (ASPT) index. We demonstrate that a qualitative index of riparian integrity can be positively associated with stream ecological status. This introduction to the CROSSLINK project shows the potential for our replicated study with its panoply of ecosystem attributes to help guide management decisions regarding the use of forested riparian buffers in human-impacted landscapes. This knowledge is highly relevant in a time of rapid environmental change where freshwater biodiversity is increasingly under pressure from a range of human impacts that include habitat loss, pollution, and climate change

New molecular methods to assess biodiversity. Potentials and pitfalls of DNA metabarcoding: a workshop report

This report presents the outcome of the joint work of PhD students and senior researchers working with DNA-based biodiversity assessment approaches with the goal to facilitate others the access to definitions and explanations about novel DNA-based methods. The work was performed during a PhD course (SLU PNS0169) at the Swedish University of Agricultural Sciences (SLU) in Uppsala, Sweden. The course was co-organized by the EU COST research network DNAqua-Net and the SLU Research Schools Focus on Soils and Water (FoSW) and Ecology - basics and applications. DNAqua-Net (COST Action CA15219, 2016-2020) is a network connecting researchers, water managers, politicians and other stakeholders with the aim to develop new genetic tools for bioassessment of aquatic ecosystems in Europe and beyond. The PhD course offered a comprehensive overview of the paradigm shift from traditional morphology-based species identification to novel identification approaches based on molecular markers. We covered the use of molecular tools in both basic research and applied use with a focus on aquatic ecosystem assessment, from species collection to the use of diversity in environmental legislation. The focus of the course was on DNA (meta)barcoding and aquatic organisms. The knowledge gained was shared with the general public by creating Wikipedia pages and through this collaborative Open Access publication, co-authored by all course participants

Forested riparian buffers change the taxonomic and functional composition of stream invertebrate communities in agricultural catchments

Riparian zones form the interface between stream and terrestrial ecosystems and play a key role through their vegetation structure in determining stream biodiversity, ecosystem functioning and regulating human impacts, such as warming, nutrient enrichment and sedimentation. We assessed how differing riparian vegetation types influence the structural and functional composition (based on species traits) of stream invertebrate communities in agricultural catchments. We characterized riparian and stream habitat conditions and sampled stream invertebrate communities in 10 independent site pairs, each comprising one “unbuffered” reach lacking woody riparian vegetation and a second downstream reach with a woody riparian buffer. Forested riparian buffers were associated with greater shading, increased gravel content in stream substrates and faster flow velocities. We detected changes in invertebrate taxonomic composition in response to buffer presence, with an increase in sensitive Ephemeroptera, Plecoptera and Trichoptera (EPT) taxa and increases in key invertebrate species traits, including species with preference for gravel substrates and aerial active dispersal as adults. Riparian vegetation independently explained most variation in taxa composition, whereas riparian and instream habitat together explained most variation in functional composition. Our results highlight how changes in stream invertebrate trait distributions may indirectly reflect differences in riparian habitat, with implications for stream health and cross-ecosystem connectivity

Genetic Variation of Juniperus squamata var. morrisonicola Based on ISSR Markers

玉山圓柏（Juniperus squamata var. morrisonicola）生長在海拔3,000公尺以上高山，是台灣針葉樹種分布最高者，群落的形態有極大差異，生長型的變異範圍由匍伏灌木至直立喬木。以13個ISSR引子研究玉山圓柏10個族群160個個體，共得到173個條帶，其中83為多型性條帶（48.98%）。AMOVA分析顯示，地理區域間變方成分佔3.85%（P=0.0933），地區內族群間佔9.06%（P < 0.001），族群內個體間變方成分佔87.09%（P <0.001）。POPGENE的分析結果顯示，各族群內之基因歧異度值由0.294- 0.372，總的Nei’s基因歧異度（Ht）為0.384，遺傳分化係數（Gst）為0.117，基因流（Nm）為3.765。由這些結果看來，玉山圓柏族群基因流暢通，族群間分化程度與一般針葉樹相近。比較關山族群喬木與灌木兩種不同生長型個體，發現兩種生長型間無顯著遺傳差異。南湖大山地區的南湖池直立喬木族群與南湖大山北峰匍伏灌木族群間，有顯著的遺傳分化。Juniperus squamata var. morrisonicola is distributed in mountains above 3,000m in altitude and is the conifer species with highest altitudinal distribution in Taiwan. The species is highly variable in growth forms, ranging from low procumbent to tall tree. One hundred and sixty individuals from ten populations were studied for ISSR variation. One hundred and seventy-three bands were observed using 13 primers. Eighty-three (48.98%) were polymorphic bands. AMOVA analysis revealed that the percentages of variance components attributable to variation among regions, among populations within regions, and among individuals within populations were 3.85% (p=0.0933), 9.06% (p<0.001), and 87.09% (p<0.001), respectively. The result indicated that there was a slight but signification differentiation among populations. However, the major variation existed among individuals within populations. POPGENE analysis revealed that the total gene diversity (Ht) of the species was 0.384 and the gene diversities of populations ranged from 0.294 to 0.372. The population genetic diversity index (Gst) was 0.117 while the gene flow index (Nm) was 3.765. The result indicated that the gene flow among populations was relatively unrestricted. Population differentiation was similar to other conifer species. No genetic differentiation between shrub and tree growth forms was observed in Kuanshan population. However, a significat genetic differentiation existed betweet tree-form Nanhuchi population and shrub-form Nanhutashanbefeng population in Nanhutashan region.中文摘要----------------------------------------------Ⅰ 英文摘要----------------------------------------------Ⅱ 壹、前言---------------------------------------------- 1 貳、前人研究------------------------------------------ 3 參、材料與方法----------------------------------------12 肆、結果--------------------------------------------- 22 伍、討論--------------------------------------------- 35 陸、結論--------------------------------------------- 46 柒、引用文獻----------------------------------------- 4