Non-metric Multidimensional Scaling Ordination Research Articles

Spatiotemporal variation in the structure and diet types of bird assemblages in tropical dry forest in southwestern Mexico

ABSTRACT Tropical dry forest is one of the most threatened ecosystems in the Neotropics as a result of agriculture, cattle ranching, and timber extraction. The effects of disturbance on the bird communities of this ecosystem have not been well studied. In this study, we evaluated changes in the richness, abundance, and diversity of birds and their diet types in the following land uses in southwestern Mexico: agroecosystem, palm grove, forest edge, and undisturbed forest. Visual and auditory sampling was performed for 1 year (August 2014 to July 2015) in 40 circular plots with a radius of 30 m (10 plots per land use). Differences in the composition and the abundance of bird species in plots of distinct land use were analyzed by a non-metric multidimensional scaling (NMDS) ordination to determine similarity among the data. In total, 101 species from 29 families were found in the study sites. The agroecosystem presented the greatest species richness (70 species), followed by undisturbed forest (57). Overall ...

Patterns of Spatial Diversity and Structure of Mangrove Vegetation in Pacific West-Central Mexico

Mangrove ecosystems are important sources of goods and services to people, supporting ecological, biological, social and economic values. Nevertheless the scale of human-impact on mangroves in many countries has increased dramatically over the past years. Understanding their structure and plant composition is decisive for a proper design of conservation and management strategies, therefore we assessed patterns of floristic composition and structure together with their spatial and temporal environmental variability. Sixty-five 100 m2 permanent plots were established across the study area in order to cover the full range of structural and floristic variation. We sampled interstitial water properties (salinity, total dissolved solid, pH, oxygen dissolved and temperature) during the dry and the wet seasons. We ran non-metric multidimensional scaling ordinations (NMDS) to discern both floristic composition and structural changes related to interstitial water. We also ran multiple linear regression analyses, to determine the relationship between interstitial water with stand structural variables. Results showed a floristic gradient related to salinity while structure indicated by stand density and tree sizes, were explained primarily by salinity along the whole year; oxygen dissolved and pH were also significant in both wet and dry season while temperature was only important in the dry season.

Effects of Broussonetia papyrifera invasion and land use on vegetation characteristics in a tropical forest of Ghana

The purpose of this study was to evaluate the effects of Broussonetia papyrifera (paper mulberry) invasion and land use on the floristic composition of a dry semi-deciduous forest in Ghana. Forty-five plots (25 m × 25 m each), distributed among three land uses—selectively logged (SL); abandoned farmlands (AF); and an undisturbed reference (RF)—were surveyed. Results showed lower tree species richness (S), diversity (H′), evenness (S) and basal area (BA) in the SL (46, 0.78, 0.32 and 269.12 m2 ha−1, respectively) and AF (40, 0.53, 0.45, and 131.16 m2 ha−1) sites compared to the RF site (79, 2.66, 0.87, 963.72 m2 ha−1). Similar patterns were found at the shrub layer, but no differences were observed at the herb layer. Non-metric multidimensional scaling ordination revealed distinct species composition among the land uses. The two disturbed habitats, SL and AF, were associated with increased B. papyrifera invasion particularly in the overstory, with importance value index and mean relative density of 45 and 65.03%, and 42 and 53.29%, correspondingly. However, the species was only sparsely represented in the RF site. Tree density of B. papyrifera correlated negatively with H′, S, E, BA, and native tree density and richness. These findings highlight the strong link between human land use (i.e., logging and slash-and-burn farming), invasion, and vegetation characteristics, and suggest the need to limit these disturbances to conserve biodiversity within tropical forest ecosystems.

Effect of heat on soil seedbank of three contrasting physiognomies in Shasha forest reserve, Southwestern Nigeria

The effects of soil heating which usually occur during forest fires on the floristic composition and seed density of the soil seed bank of Shasha forest reserve in Southwestern Nigeria was investigated and the potential of the soil seedbank in forest restoration process (especially after a fire) was examined. Three distinct sites (Regrowth forest, Gmelina and Pinus plantations) were selected in the forest reserve. Species enumeration, identification and distribution into families of the standing vegetation were carried out. Soil samples were collected at 0–15 cm depth from each plot in March 2012. One set of replicate samples was heated in an oven until the soil reached 80 °C (to simulate typical temperature at soil surface during forest fires) while the other serves as a control. They were subjected to seedling emergence for six months to determine the density and species composition of the seed banks of the study sites. Seedling emergence result for heated and unheated soil samples showed that the seedbank density was higher in control than heated samples in the three sites. Few woody species emerged from the soil seedbank of three study sites and in both control and heated samples. There was a significant difference in total seed density when treatments were compared (P < 0.05) and no significant difference (P > 0.05) when sites were compared. Diversity and evenness indices follow the order Regrowth forest > Pinus plantation > Gmelina plantation. NMDS (non-metric multi-dimensional scaling) ordination revealed low similarity in the species composition of extant vegetation and seedbank. The potential of vegetation restoration of the disturbed forest reserve from seed bank is limited, and heat from fire had negative effects on the seed bank characteristics of the forest but selectively enhanced the emergence of species like Pinus carribaea.

Influences of diel and tidal cycles on fish assemblage in eelgrass (Zostera marina) bed of southern Korea during autumn

Short-term tidal and diel variations of autumn fish assemblage in a Zostera marina bed were investigated using 3 h interval samplings for 24 h in both spring and neap tide using a small beam trawl. A total of 1 346 fishes belonging to 19 species were collected at spring tide, whereas 1 115 fishes belonging to 17 species were at neap tide. The common fish species were Nuchequula nuchalis, Acanthogobius flavimanus, Takifugu niphobles, Acentrogobius pflaumii, and Pholis nebulosa with the former three species dominating at spring tide, while the latter two species being abundant at neap tide. Diel variation in abundance was significant with higher abundance at night than day, but there were no significant differences between spring and neap tides, and between ebb and flood tides (three-way ANOVAs). Diel variation in the abundance of fishes may be influenced by tidal range and cycle, and day-night differences of food availability and behaviors of fishes indirectly. Non-metric multidimensional scaling (nMDS) ordination and analysis of similarity (ANOSIM) results revealed significant differences in species compositions both between day and night, and between spring and neap tide. Eelgrass beds are highly productive marine ecosystem, and thus, our results will contribute to conservation of seagrass ecosystem in the study area.

Naturally recruited herbaceous vegetation in abandoned Belgian limestone quarries: towards habitats of conservation interest analogues?

We examined if naturally recruited herbaceous vegetation in abandoned Belgian limestone quarries tend towards plant communities analogous to semi-natural habitats of conservation interest. We studied taxon-based assemblages (using two-dimensional non-metric multidimensional scaling ordination) and functional patterns (relative to Grime’s competitor, stress tolerator and ruderal plant strategies (CSR) classification) of plant communities (n = 360 plots) among three different time periods after quarry abandonment ( 20 y). We compared those successional assemblages with those of habitat of conservation interest plant communities (n = 53 plots): lowland hay meadows and rupicolous, xerophilous and mesophilous calcareous grasslands. Our results indicate that naturally recruited herbaceous vegetation compositionally resembled mesophilous grassland, even though initial substrate conditions were more similar to rupicolous or xerophilous grasslands. The specific successional pathway we found in CSR state-space differs from Grime's predictions because there was a functional shift in plant assemblages from dominance by ruderals to dominance by stress-tolerant species. The differences in successional trajectories we found on different types of rock substrate suggest that conservation management should adopt a site-specific approach, recognizing that the highest probabilities of success on hard limestone will be restoration to calcareous grassland analogues.

Feeding Relationships among Six Seagrass-associated Fishes in the Northeastern Gwangyang Bay, Southern Korea

We conducted dietary analyses of six seagrass-associated fish species inhabiting northeastern Gwangyang Bay, Korea. These six species consumed a variety of benthic invertebrates and teleosts, but their preferences for different food resources varied. Although all species consumed crustaceans, the contributions of different crustacean taxa differed among the species’ diets. Caridean shrimps and crabs were a significant part of the Hexagrammos agrammus and H. otakii diets, respectively, while amphipods were consumed mainly by Sebastes inermis. Caridean shrimps and prawns were abundant within the Lateolabrax japonicas diet, but were not common prey resources for Pseudopleuronectes yokohamae or S. schlegelii. Polychaetes and ophiurids were ingested by P. yokohamae, and the former prey taxon also made moderate contributions to the diets of H. agrammus and L. japonicus. With the exception of P. yokohamae, the diets of all species included teleosts. Teleosts contributed the largest proportion of the S. schlegelii diet, followed by the S. inermis and L. japonicas diets; however, H. agrammus and H. otakii rarely consumed teleosts. Non-metric multidimensional scaling (nMDS) ordination plots and permutational analysis of variance (PERMANOVA) revealed the variation in dietary composition among species and the contributions of each prey taxon. These interspecific differences in diet increase the range of food resources available to these fishes, thereby reducing competition for resources within the fish community in this region.

Legacy effects of prescribed fire season and frequency on soil properties in a Pinus resinosa forest in northern Minnesota

Abstract Prescribed fire is a widely used ecosystem management approach and the vast majority of burns are conducted during the dormant season; however, these burning conditions (and therefore the type and persistence of fire effects) often differ from those of natural or historical fire regimes. Therefore, we leveraged a historical study (conducted 1959–70) with remeasurements in 2015 to evaluate effects of fire season (dormant, summer), frequency (annual, biennial, periodic), and their interaction on soil physical and chemical properties in a red pine (Pinus resinosa Ait.) forest in northern Minnesota, USA. To protect against across-year differences in sampling and analysis, we used a meta-analysis approach to evaluate treatment effects on soil properties. We also used non-metric multidimensional scaling (NMDS) ordination to investigate legacy (>45 years post-fire) treatment effects. The greatest effects of fire occurred in organic horizons, and decreased with depth. In the short-term, fire decreased organic horizon depths and nitrogen (N) and increased base cations (K, Ca, Mg) and pH in the mineral soil, whereas effects on phosphorus (P) were variable. Prescribed fire treatments had legacy effects on organic horizon and mineral soil properties >45 years post-fire. In general, summer burns decreased nutrient stocks, whereas dormant season burns increased nutrient stocks, and the majority of legacy effects occurred in annual burn treatments, in both seasons. Legacy effects of summer burns decreased organic horizon depths, organic matter, nutrient stocks (N, P, K), and pH, as well as lower (0–15 cm) mineral soil N; whereas, the dormant annual burn increased Ca in the total forest floor and N and P in the upper (15–91 cm) mineral soil. In contrast, the summer annual burn increased P, whereas the dormant annual burn decreased pH in the lower mineral soil. Trends in short- and long-term effect sizes appeared to differ by season of burning and further magnified by increased fire frequency within season. Relative to dormant season burns, summer burns resulted in immediate and long-lasting desirable effects for red pine ecosystems (e.g., decreased forest floor depths and nutrient stocks) without persistent undesirable effects (e.g., increased nutrient stocks or changes in cation exchange capacity, soil texture, and bulk density) in the mineral soil. Our results suggest that summer burns may be a valuable approach to increase the variability in burn schedules representative of historical regional fire regimes in red pine forests, and may help promote soil characteristics that support overall ecosystem health.

Ecological differentiation, speciation, and rarity: How do they match in Tephroseris longifolia agg. (Asteraceae)?

Tephroseris longifolia agg. is a complex group of outcrossing perennials distributed throughout Central Europe. Recent morphological study revealed six morphotypes corresponding to five previously distinguished subspecies, together with Alpine and Pannonian morphotypes of T. longifolia subsp. longifolia. The delimited morphotypes differ in relative DNA content, geographical range, and rarity. We compared ecological niches of the six morphotypes in order to assess the impact of ecological differentiation on the speciation processes within the T. longifolia agg. Further, we examined whether morphotypes with small range are more ecologically specialized than their widespread relatives. The distribution area of the aggregate includes the Alps, Apennines, Carpathians, and the Pannonian Basin. Ecological variables linked to climate, topography, soil, and vegetation were gathered from 135 circular plots recorded in 35 localities. Related variables were grouped to describe the partial ecological niches: climatic, topographic, pedological, biotic, and coenotic (based either on vascular plants or on bryophytes), each of them visualized as an envelope in the two‐dimensional nonmetric multidimensional scaling ordination space. Each partial ecological niche for a given morphotype was characterized by its position (location of the envelope centroid), breadth (surface of the envelope), and overlaps with envelopes of the other morphotypes. Mantel statistics based on Spearman correlation coefficients were used to quantify differentiation of morphotypes in ecological parameters represented by the partial ecological niches. The significant niche differentiation was confirmed for climatic, topographic, pedological, and vascular plant‐based coenotic niches. Ecological niche differentiation corresponded well to morphological and partially also to karyological differentiation. Narrowly distributed morphotypes occupied more specific habitats and had narrower ecological niches than their widespread relatives. Ecological differentiation could be considered an important driver in allopatric speciation within the T. longifolia agg. Our results demonstrate that quantification of ecological divergence is helpful in assessing evolutionary history of closely related taxa.

Editorial

Natural disturbances alter the biophysical conditions of ecosystems, influencing patterns of structure, composition, and successional dynamics. Following high severity natural disturbance in forest ecosystems, land-managers sometimes employ salvage harvesting to harvest trees killed or damaged by the disturbance agent. Despite its widespread practice, the effects of salvage harvesting on many ecosystem functions and species assemblages are still poorly understood. This study presents the first attempt to document and analyze the effects of salvage harvesting on macrofungal communities following catastrophic wind disturbance. On 27 April 2011, an EF3 tornado damaged forest stands within the Oakmulgee Ranger District of the Talladega National Forest in west-central Alabama, USA. Following the event, portions of some stands were subject to salvage harvesting. In 2016, we established three treatments, undisturbed, tornado disturbed, and salvage harvested, in stands that were dominated by Pinus palustris P. Miller prior to the 2011 disturbance events. Throughout the sample period, 546 occurrences of 84 macrofungal species were recorded. Tornado disturbed areas hosted the highest macrofungal species richness overall. Undisturbed areas hosted the highest species richness for ectomycorrhizal macrofungi. Salvage harvested areas had reduced species richness for both saprotrophic and ectomycorrhizal macrofungi compared to tornado disturbed plots. Non-metric multidimensional scaling ordination and permutational multivariate analysis of variance indicated that all three treatments differed in macrofungal community composition. The results indicated that salvage harvesting following catastrophic wind disturbance has the capacity to reduce macrofungal species richness and fruiting abundance. The reduction in deadwood volume and alterations to the ectomycorrhizal-associating plant community documented at salvage harvested sites is likely responsible for the observed differences in macrofungal fruiting patterns. The implications of reduced macrofungal richness in the early stages of forest development following catastrophic disturbance should be subject to long-term studies.

Wetland microhabitats support distinct communities of aquatic macroinvertebrates

ABSTRACTThe drivers of aquatic macroinvertebrate distribution in Prairie Pothole Region wetlands are not as well understood as in other aquatic ecosystems (e.g. rivers or lakes). We collected aquatic macroinvertebrates from 35 fishless prairie pothole wetlands in Alberta, including two habitat zones: the emergent zone and the open-water zone. Within each zone, we collected a vegetation sample and a water column sample, thus capturing four distinct microhabitats. We tested for community differences among these microhabitats with nested ANOVAs, looking at macroinvertebrate abundance, taxa richness, and evenness. We also visualized trends in community composition among the microhabitats with nonmetric multidimensional scaling ordination. Interestingly, we observed no difference in macroinvertebrate communities between the open-water and the emergent habitat zones. However, we found significant differences in richness and evenness between water column and vegetation sample types nested within habitat zones. Additionally, we observed high taxonomic turnover between sample types. Our results emphasize the importance of within-zone microhabitats in structuring aquatic macroinvertebrate communities in prairie pothole wetlands, and the relative insignificance of emergent and open-water habitat zone distinctions. Future analyses of macroinvertebrates in wetlands should sample both the vegetation and the water column, regardless of habitat zone, to prevent biased surveys of macroinvertebrate communities.

海拔变化对凤阳山针阔混交林地土壤微生物群落的影响

PDF HTML阅读 XML下载 导出引用 引用提醒 海拔变化对凤阳山针阔混交林地土壤微生物群落的影响 DOI: 10.5846/stxb201708211503 作者: 作者单位: 南方现代林业协同创新中心，江苏省水土保持与生态修复重点实验室，南京林业大学林学院,南方现代林业协同创新中心，江苏省水土保持与生态修复重点实验室,南方现代林业协同创新中心，江苏省水土保持与生态修复重点实验室，南京林业大学林学院,南方现代林业协同创新中心，江苏省水土保持与生态修复重点实验室，南京林业大学林学院,南方现代林业协同创新中心，江苏省水土保持与生态修复重点实验室,浙江凤阳山—百山祖国家级自然保护区凤阳山管理处,浙江凤阳山—百山祖国家级自然保护区凤阳山管理处,浙江凤阳山—百山祖国家级自然保护区凤阳山管理处 作者简介: 通讯作者: 中图分类号: 基金项目: 林业科学技术推广项目[2015]17号；江苏省高校自然科学研究重大项目（15KJA220004）；江苏省高校研究生科研创新项目（KYZZ16-0323） Effects of altitude on soil microbial community in Fengyang Mountain coniferous and broad-leaved forest Author: Affiliation: Jiangsu Province Key Laboratory of Soil and Water Conservation and Ecological Restoration,Co-Innovation Center for the Sustainable Forestry in Southern China,College of Forestry,Nanjing Forestry University,Jiangsu Province Key Laboratory of Soil and Water Conservation and Ecological Restoration,Co-Innovation Center for the Sustainable Forestry in Southern China,College of Forestry,Nanjing Forestry University,Jiangsu Province Key Laboratory of Soil and Water Conservation and Ecological Restoration,Co-Innovation Center for the Sustainable Forestry in Southern China,College of Forestry,Nanjing Forestry University,Jiangsu Province Key Laboratory of Soil and Water Conservation and Ecological Restoration,Co-Innovation Center for the Sustainable Forestry in Southern China,College of Forestry,Nanjing Forestry University,Jiangsu Province Key Laboratory of Soil and Water Conservation and Ecological Restoration,Co-Innovation Center for the Sustainable Forestry in Southern China,College of Forestry,Nanjing Forestry University,The Fengyangshan Management Office of Fengyang Mountain-Baishanzu National Nature Reserve in Zhejiang Province,Longquan,China,The Fengyangshan Management Office of Fengyang Mountain-Baishanzu National Nature Reserve in Zhejiang Province,Longquan,China,The Fengyangshan Management Office of Fengyang Mountain-Baishanzu National Nature Reserve in Zhejiang Province,Longquan,China Fund Project: 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:风阳山自然保护区是森林生态类型自然保护区，针阔混交林是保护区内的重要森林类型。为明确海拔变化对高山针阔混交林地土壤微生物群落的影响及初步影响机理，了解气候变暖后典型林分土壤微生物群落结构的变化。以黄山松在凤阳山的分布范围800-1800 m为准，选取900、1100、1300、1500、1700 m 5个海拔梯度，在每个海拔梯度的阳坡内选取排水较好、坡度较缓、长势适中的3个标准样地（20 m×20 m），于2016年8月用蛇形法于每块样地取样，用冰盒带回实验室，测定土壤理化性质及微生物群落。采用磷脂脂肪酸（PLFA）图谱分析确定土壤微生物群落组成及其丰度，同时对土壤微生物群落组成进行非度量多维标度（NMDS）排序，对土壤微生物群落组成结构进行分析。结果表明：随着海拔升高，针阔混交林样地内植物种类组成有所变化。土壤养分含量呈先升高后降低的趋势，差异性显著（P < 0.05）；土壤微生物群落丰度之间存在显著差异，革兰氏阴性细菌丰度在高海拔处较大；土壤微生物群落组成非度量多维标度（NMDS）排序显示，随海拔升高，土壤微生物群落组成发生明显改变，可以分为三个类群，各海拔土壤微生物群落结构在两个NMDS轴上均呈现出显著差异（P < 0.05）。通过对土壤微生物群落丰度与土壤理化性质的冗余分析（RDA），发现土壤pH、容重、含水量、及有效磷含量对对土壤微生物群落丰度有不同程度的影响，土壤革兰氏阳性细菌、放线菌丰度与各土壤因子之间均有显著相关关系；革兰氏阴性细菌受土壤含水量及有效磷的含量影响较大；真菌丰度与土壤pH及有机碳含量之间存在相关关系；厌氧菌及16：1ω5c丰度与土壤因子间相关性较弱。海拔变化所引起的土壤理化性质的改变，是影响土壤微生物群落丰度的因素；6个微生物群落对海拔的适应程度是不同的，革兰氏阴性细菌对高海拔的低温环境适应能力较强。 Abstract:Fengyang Mountain Nature Reserve is a natural reserve of forest ecological type, coniferous and broad-leaved forest is an important forest type in the nature reserve. To understand the impacts of altitude change on soil microbial communities and soil physicochemical properties, we explored the physicochemical properties and microbial community composition of alpine coniferous and broad-leaved forest, the main vegetation types of Fengyang Mountain. Based on the distribution range of Pinus taiwanensis in Fengyang mountain, 900 m, 1100 m, 1300 m, 1500 m, and 1700 m were selected as five altitudinal gradients, and three standard plots were set at each elevation gradient (20 m×20 m), which were sampled in August 2016. Using phospholipid fatty acids (PLFA) spectrum analysis to determine the composition and abundance of soil microbial community, and the soil microbial community composition of non-metric multidimensional scaling (NMDS) ordination, on soil microbial community structure was analyzed. The results showed that the composition of plant species in coniferous and broad-leaved forests has changed. The soil nutrient content first increased and then decreased, and was significantly reduced at high altitudes (P < 0.05), and there were significant differences between soil microbial community abundance. Gram-negative bacterial abundance was higher at high altitudes. NMDS analysis show that the increase in altitude changed the soil microbial community, which can be divided into three groups. Soil microbial community structure at different altitudes showed significant differences in the two NMDS axes (P < 0.05). The redundancy analysis showed that soil bulk density, water content, and pH effected soil microbial composition in different ways:soil gram-positive bacterial and antino bacterial abundance were significantly influenced by the soil properties we studied, whereas soil water content and available phosphorus content mainly affected soil gram-negative bacterial abundance, and the abundance of anaerobic bacteria and 16:1ω5c was weakly correlated with soil properties. The change in soil physicochemical properties caused by altitude was the main factor affecting soil microbial community abundance. The adaptability of six microbial communities to altitude was different; and the gram-negative bacteria have the strongest adaptability to high altitude and low temperature environment. 参考文献 相似文献 引证文献

Biostimulation of nutrient additions on indigenous microbial community at the stage of nitrogen limitations during composting

Microorganisms can play a crucial role in the efficiency for composting, which are essential for converting the organic wastes into a well-stabilized, value added product. However, the activity of most of the key functional microorganisms were inhibited due to the limited special nutrient substances or other physiochemical factors during composting, which further affected the quality of compost. The study was conducted to investigate the effects of enriched ammonium (NH4+-N) and organic nitrogen (Org-N) on indigenous microbial community and whether nitrogen (N) nutrient additions could modify the special species during composting. The results showed that the abundance and structure of bacterial community had distinctly diverse responses to different N nutritional treatments (no nutrient addition, NH4+-N addition, and Org-N addition). The addition of N sources enhanced the abundance of corresponding uncultured indigenous species negatively related to the factor of NH4+ and Org-N in redundancy analysis (RDA) during composting but the effect of NH4+ was more significant than Org-N. Nonmetric multidimensional scaling ordination (NMDS) demonstrated that both the two N additions changed bacterial community but had different duration for affecting bacterial composition. Conclusively, an optimized method for regulating the key stains with special biological capacity is proposed by controlling the single limiting-nutrient factor sharply decreasing at one of composting stages and negatively related to the key species in RDA.

Comparisons between Cambrian Lagerstätten assemblages using multivariate, parsimony and Bayesian methods

Exceptional fossil deposits exhibiting soft-part preservation, or Konservat-Lagerstätten, are prevalent in Cambrian rocks and provide detailed information on fossil assemblages not available from conventional deposits. It has long been recognised that many of these assemblages exhibit certain taxonomic similarities, with many elements seemingly having cosmopolitan distributions. These types of assemblages, particularly those of Cambrian age, have become known as Burgess Shale-type (BST) biotas, named for the famous deposit in the Canadian Rocky Mountains where fossils preserved in this way were first discovered. This study provides the first broad-scale analysis of the assemblage relationships between all major BST biotas. We compiled a database of the presences and absences of over 600 genera within 12 Lagerstätten from Laurentia, Siberia, South China and East Gondwana, ranging in age from Cambrian Series 2 through Series 3 (late-early to middle Cambrian; c. 518–502Ma), and analysed this using a variety of quantitative methods in order to investigate the relationships between these sites. Non-metric multidimensional scaling (NMDS) ordination, cluster analysis and Parsimony Analysis of Endemicity (PAE) were used to group localities and examine relationships. We also used Bayesian inference and illustrate the benefits of this approach to biogeographic studies. Results suggest that both space and time have important effects on the taxonomic constitution of BST biotas, and that the similarity of these assemblages appears to increase from Series 2 through Series 3, largely driven by increases in cosmopolitanism of biomineralised taxa such as trilobites and brachiopods. There is also evidence of higher-level taxonomic turnover across this period. Endemic taxa help amplify these patterns, despite their frequent exclusion from biogeographic analyses.

Site preparation severity influences lodgepole pine plant community composition, diversity, and succession over 25 years

Lodgepole pine (Pinus contorta var. latifolia Engelm.) ecosystems of central British Columbia face cumulative stresses, and management practices are increasingly scrutinized. We addressed trade-offs between “light-on-the-land” versus more aggressive silvicultural approaches by examining plant communities and indicator species (non-natives, berry producers, epiphytes, mycotrophs, pine rust alternate hosts) across a gradient of five or six site preparation treatments at the Bednesti trial (established 1987). We tested whether more severe site preparation (i) caused plant community composition to diverge from a 35- to 46-year-old reference forest, (ii) accelerated succession by hastening crown closure, or (iii) delayed succession by promoting seral species. Nonmetric multidimensional scaling (NMDS) ordination showed all treatments converging toward the reference forest composition. At 10 years, succession was incrementally delayed by more severe treatments; at 25 years, only burned windrows were still delayed. Mixed-effects models based on site preparation severity were better than crown closure models for 11 of 13 variables tested, suggesting that mostly belowground processes drive succession in these infertile ecosystems. Invasive hawkweeds persisted on all treatments at 25 years. Limited, contradictory data did not support using mechanical or fire treatments to reduce alternate hosts of pine stem rusts. Long-term trials such as Bednesti highlight the need for ecosystem-specific strategies and diverse approaches to accommodate conflicting benefits and risks of disturbance in forests.

Assessment of Wildlife Habitat Attributes at Restoration Projects on Northern Wisconsin Lakeshores

Abstract Housing development along lakeshores typically results in the loss of native shoreline vegetation, which can negatively impact habitat structure and associated wildlife populations. We evaluated vegetation restoration efforts on 2 lakeshores in Vilas County, WI, and contrasted them with undeveloped reference lakeshores. The primary goal of the restoration activities was to restore native understory vegetation and habitat structure. Initial measurements made at reference lakeshores showed greater visual obstruction density, greater sapling and shrub densities, greater abundance of downed woody material, and higher canopy coverage relative to initial measurements made at developed lakeshore sites. Three years post-restoration we observed significant increases in visual obstruction density and increased shrub and sapling density at restoration sites. While restoration of complex understory habitats is a slow and uncertain process, a nonmetric multi-dimensional scaling ordination of wildlife habitat ...

Distribution Patterns of the Freshwater Oligochaete Limnodrilus hoffmeisteri Influenced by Environmental Factors in Streams on a Korean Nationwide Scale

Aquatic oligochaetes are very common in streams, and are used as biological assessment indicators as well as in the biological management of organic-enriched systems. In this study, we analyzed the effects of environmental factors influencing the distribution of aquatic oligochaetes Limnodrilus hoffmeisteri in streams. We used 13 environmental factors in three categories (i.e., geography, hydrology, and physicochemistry). Data on the distribution of oligochaetes and environmental factors were obtained from 1159 sampling sites throughout Korea on a nationwide scale. Hierarchical cluster analysis (HCA) and nonmetric multidimensional scaling (NMDS) were performed to analyze the relationships between the occurrence of aquatic oligochaetes and environmental factors. A random forest model was used to evaluate the relative importance of the environmental factors affecting the distribution of oligochaetes. HCA classified sampling sites into four groups according to differences in environmental factors, and NMDS ordination reflected the differences of environmental factors, in particular, water depth, velocity, and altitude, among the four groups defined in the HCA. Furthermore, using a random forest model, turbidity and water velocity were evaluated as highly important factors influencing the distribution of L. hoffmeisteri.

Macroinvertebrate‐based bioassessment of rivers in Addis Ababa, Ethiopia

AbstractChemical‐based studies have shown pollution of rivers in Addis Ababa, Ethiopia. However, as bioassessment is not a component of the river assessment and monitoring programmes, information on the ecological status of the rivers is limited. The study assessed the ecological status of the Little and Greater Akaki Rivers using macroinvertebrates. Macroinvertebrates were collected from twelve sites twice in the dry and wet seasons. There was abundance of few tolerant, collector‐gatherer taxa with a loss of most sensitive taxa that used to be part of the river systems. Macroinvertebrate communities from upper and lower reaches showed complete differentiation on the nonmetric multidimensional scaling (NMS) ordination graph with upstream reaches composed of relatively sensitive taxa while the lower reaches dominated by tolerant taxa. Multiresponse permutation procedure (MRPP) showed significant difference between the two reaches. Macroinvertebrate communities from the dry and wet seasons did not show differentiation on the NMS ordination graph and MRPP did not show significant difference. Both rivers scored low in the South African Scoring System (SASS 5) and ETHbios, indicating ecological degradation. The results suggest that several decades of environmental degradation might have led to impoverished regional species pool, consisting mainly tolerant and generalist taxa constant throughout the year.

Taphonomy and palaeoecology in the upper Barremian of the SW Iberian chain (Spain): A model to compare taxonomy and diversity of biotas from different coeval basins

A detailed study of the floral and faunal diversity of an upper Barremian lentic ecosystem was performed by examining 50,000microfossils. The study provides an assemblage of 41 species of charophytes, spermatophytes, ostracods, molluscs, and vertebrates (including eggshells). The main goal of this study is to reconstruct the palaeoecology of a fluvio-lacustrine and associated carbonate depositional system, by integrating the sedimentology, taphonomy, and diversity from twelve horizons cropping out in the Buenache de la Sierra and the Las Hoyas basins. The studied area corresponds to the lowermost succession of the Tragacete Formation (Serranía de Cuenca, Iberian chain). Four facies associations (polymictic alluvial; carbonate palustrine and lacustrine; eutrophic lacustrine; and calcarenitic drainage facies) were correlated to the composition of the fossil assemblages, which have yielded a set of taphofacies confirmed by the non-metric multidimensional scaling ordination test of all the horizons. The taphofacies are: (α) dominated by bones and plant leaves, (β) by charophytes-ostracods-bivalves and eggshells, and (γ) by coal-leaves and bones. The Tragacete depositional system consists of demic and mostly autochthonous (non-catastrophic) fossil associations. A mixture of aquatic and terrestrial plants, freshwater molluscs and ostracods coupled with aquatic and terrestrial vertebrate species fosters a biodiversity typical of depositional environments that are congruent with modern floodplain wetland systems. These floodplain wetlands are characterised by a combination of periodically inundated ponds, small lakes, and floodplain areas with terrestrial habitats. As such, they provide suitable environments for the diversification and colonisation of charophytes, ostracods, gastropods, fish, and an ample herpetofauna. The abundance and diversity of eggshells also suggest the development of nesting areas, whereas the occurrence of charred cheirolepidiacean conifer would indicate intermittent wild fires linked to drought events. The taxonomic breadth of this ecosystem is characterised by the taxonomic distinctness index, which, in turn, becomes a referential model to which other Lower Cretaceous microfossil sites may be compared.

Effects of wind disturbance and salvage harvesting on macrofungal communities in a Pinus woodland

Abstract Natural disturbances alter the biophysical conditions of ecosystems, influencing patterns of structure, composition, and successional dynamics. Following high severity natural disturbance in forest ecosystems, land-managers sometimes employ salvage harvesting to harvest trees killed or damaged by the disturbance agent. Despite its widespread practice, the effects of salvage harvesting on many ecosystem functions and species assemblages are still poorly understood. This study presents the first attempt to document and analyze the effects of salvage harvesting on macrofungal communities following catastrophic wind disturbance. On 27 April 2011, an EF3 tornado damaged forest stands within the Oakmulgee Ranger District of the Talladega National Forest in west-central Alabama, USA. Following the event, portions of some stands were subject to salvage harvesting. In 2016, we established three treatments, undisturbed, tornado disturbed, and salvage harvested, in stands that were dominated by Pinus palustris P. Miller prior to the 2011 disturbance events. Throughout the sample period, 546 occurrences of 84 macrofungal species were recorded. Tornado disturbed areas hosted the highest macrofungal species richness overall. Undisturbed areas hosted the highest species richness for ectomycorrhizal macrofungi. Salvage harvested areas had reduced species richness for both saprotrophic and ectomycorrhizal macrofungi compared to tornado disturbed plots. Non-metric multidimensional scaling ordination and permutational multivariate analysis of variance indicated that all three treatments differed in macrofungal community composition. The results indicated that salvage harvesting following catastrophic wind disturbance has the capacity to reduce macrofungal species richness and fruiting abundance. The reduction in deadwood volume and alterations to the ectomycorrhizal-associating plant community documented at salvage harvested sites is likely responsible for the observed differences in macrofungal fruiting patterns. The implications of reduced macrofungal richness in the early stages of forest development following catastrophic disturbance should be subject to long-term studies.