An Integrated Coral Reef Ecosystem Model to Support Resource Management under a Changing Climate

Millions of people rely on the ecosystem services provided by coral reefs, but sustaining these benefits requires an understanding of how reefs and their biotic communities are affected by local human-induced disturbances and global climate change. Ecosystem-based management that explicitly considers the indirect and cumulative effects of multiple disturbances has been recommended and adopted in policies in many places around the globe. Ecosystem models give insight into complex reef dynamics and their responses to multiple disturbances and are useful tools to support planning and implementation of ecosystem-based management. We adapted the Atlantis Ecosystem Model to incorporate key dynamics for a coral reef ecosystem around Guam in the tropical western Pacific. We used this model to quantify the effects of predicted climate and ocean changes and current levels of current land-based sources of pollution (LBSP) and fishing. We used the following six ecosystem metrics as indicators of ecosystem state, resilience and harvest potential: 1) ratio of calcifying to non-calcifying benthic groups, 2) trophic level of the community, 3) biomass of apex predators, 4) biomass of herbivorous fishes, 5) total biomass of living groups and 6) the end-to-start ratio of exploited fish groups. Simulation tests of the effects of each of the three drivers separately suggest that by mid-century climate change will have the largest overall effect on this suite of ecosystem metrics due to substantial negative effects on coral cover. The effects of fishing were also important, negatively influencing five out of the six metrics. Moreover, LBSP exacerbates this effect for all metrics but not quite as badly as would be expected under additive assumptions, although the magnitude of the effects of LBSP are sensitive to uncertainty associated with primary productivity. Over longer time spans (i.e., 65 year simulations), climate change impacts have a slight positive interaction with other drivers, generally meaning that declines in ecosystem metrics are not as steep as the sum of individual effects of the drivers. These analyses offer one way to quantify impacts and interactions of particular stressors in an ecosystem context and so provide guidance to managers. For example, the model showed that improving water quality, rather than prohibiting fishing, extended the timescales over which corals can maintain high abundance by at least 5–8 years. This result, in turn, provides more scope for corals to adapt or for resilient species to become established and for local and global management efforts to reduce or reverse stressors.     

Impacts of climate change on national biodiversity population trends

Climate change has had well‐documented impacts on the distribution and phenology of species across many taxa, but impacts on species’ abundance, which relates closely to extinction risk and ecosystem function, have not been assessed across taxa. In the most comprehensive multi‐taxa comparison to date, we modelled variation in national population indices of 501 mammal, bird, aphid, butterfly and moth species as a function of annual variation in weather variables, which through time allowed us to identify a component of species’ population growth that can be associated with post‐1970s climate trends. We found evidence that these climate trends have significantly affected population trends of 15.8% of species, including eight with extreme (> 30% decline per decade) negative trends consistent with detrimental impacts of climate change. The modelled effect of climate change could explain 48% of the significant across‐species population decline in moths and 63% of the population increase in winged aphids. The other taxa did not have significant across‐species population trends or consistent climate change responses. Population declines in species of conservation concern were linked to both climatic and non‐climatic factors respectively accounting for 42 and 58% of the decline. Evident differential impacts of climate change between trophic levels may signal the potential for future ecosystem disruption. Climate change has therefore already driven large‐scale population changes of some species, had significant impacts on the overall abundance of some key invertebrate groups and may already have altered biological communities and ecosystems in Great Britain.     

Shifts in the community composition of caddisflies (Insecta: Trichoptera) in a subtropical river over three decades

1. Trichoptera is an ecologically and taxonomically diverse order, and caddisfly species are under increasing pressure from anthropogenic threats to larval habitats, rivers, and streams. 2. This study evaluated long-term changes in caddisfly communities of the Ogeechee River, a subtropical blackwater river in the south-eastern U.S. Coastal Plain, to understand how changes manifest as a result of ongoing human impacts. Two datasets separated by more than 30 years were used, each representing a 2-year monthly quantitative sampling effort (1981–1983; 2015–2017). 3. Community structure of the Ogeechee River caddisflies significantly changed, though not in ways that were predicted. The average sensitivity values of the caddisfly community declined, contrary to the expectation that increasing human impacts on a river ecosystem would promote the survival of more pollution-tolerant taxa. 4. Generic richness increased in the 2010s from the 1980s, perhaps as a result of relaxed competition following declines of large, dominant taxa. The increases in various taxa have resulted in similar overall abundance metrics between time periods, although other studies of Ogeechee River invertebrates indicate that the biomass of the new taxa is far lower than that produced by the assemblages of the 1980s. Functional richness, evenness, and dispersion were higher in the 2010s, but divergence was not. 5. This suggests that more nuanced monitoring efforts, focused on the threats to ecological function and the role of caddisflies (and other sensitive freshwater organisms), will be required to evaluate the changes in community structure and determine which taxa are most adversely affected.     

The impact of rare taxa on a fish index of biotic integrity

The index of biotic integrity (IBI) is a commonly used bioassessment tool that integrates abundance and richness measures to assess water quality. In developing IBIs that are both responsive to human disturbance and resistant to natural variability and sampling error, water managers must decide how to weigh information about rare and abundant taxa, which in turn requires an understanding of the sensitivity of indices to rare taxa. Herein, we investigated the influence of rare fish taxa (within the lower 5% of rank abundance curves) on IBI metric and total scores for stream sites in two of Minnesota's major river basins, the St. Croix (n = 293 site visits) and Upper Mississippi (n = 210 site visits). We artificially removed rare taxa from biological samples by (1) separately excluding each individual taxon that fell within the lower 5% of rank abundance curves; (2) simultaneously excluding all taxa that had an abundance of one (singletons) or two (doubletons); and (3) simultaneously excluding all taxa that fell within the lower 5% of rank abundance curves. We then compared IBI metric and total scores before and after removal of rare taxa using the normalized root mean square error (nRMSE) and regression analysis. The difference in IBI metric and total scores increased as more taxa were removed. Moreover, when multiple rare taxa were removed, the nRMSE was related to sample abundance and to total taxa richness, with greater nRMSE observed in samples with a larger number of taxa or sample abundance. Metrics based on relative abundance of fish taxa were less sensitive to the loss of rare taxa, whereas those based on taxa richness were more sensitive, because taxa richness metrics give more weight to rare taxa compared to the relative abundance metrics.     

Application of r/K selection to macroinvertebrate responses to extreme floods

1. Due to climate change, contemporary climate scenarios forecast an increase in extreme weather, which may have considerable impacts on the world's riverine ecosystems. Because the flow regime is a primary determinant of the structure and function of lotic ecosystems, changes in the weather could fundamentally alter these ecosystems through changes in hydrologic disturbance regimes. 2. In this paper, we use the abundance/biomass comparison (ABC) method, based on r/K selection theory, and event probability distribution to characterise the responses of macroinvertebrates in Taiwan mountain streams to extreme floods. 3. Severe impacts on macroinvertebrates, resulting in a large shift in community structure toward r‐selected taxa, usually were observed the year after extreme floods. 4. Macroinvertebrate communities dominated by K‐selected taxa had more individuals with traits conferring resistance to flooding disturbance, while those dominated byr‐selected taxa had more individuals with traits conferring resilience. 5. This relationship between the changes in flow regime and the ecological response of r‐ and K‐selected taxa may be exploited to understand the potential effects of flood extremes in the future, and to keep decision makers informed about the ecological consequences of climate‐mediated changes to hydrological regimes.     

Assessing the effects of land-use change on plant traits, communities and ecosystem functioning in grasslands: a standardized methodology and lessons from an application to 11 European sites

BACKGROUND AND AIMS: A standardized methodology to assess the impacts of land-use changes on vegetation and ecosystem functioning is presented. It assumes that species traits are central to these impacts, and is designed to be applicable in different historical, climatic contexts and local settings. Preliminary results are presented to show its applicability. METHODS: Eleven sites, representative of various types of land-use changes occurring in marginal agro-ecosystems across Europe and Israel, were selected. Climatic data were obtained at the site level; soil data, disturbance and nutrition indices were described at the plot level within sites. Sixteen traits describing plant stature, leaf characteristics and reproductive phase were recorded on the most abundant species of each treatment. These data were combined with species abundance to calculate trait values weighed by the abundance of species in the communities. The ecosystem properties selected were components of above-ground net primary productivity and decomposition of litter. KEY RESULTS: The wide variety of land-use systems that characterize marginal landscapes across Europe was reflected by the different disturbance indices, and were also reflected in soil and/or nutrient availability gradients. The trait toolkit allowed us to describe adequately the functional response of vegetation to land-use changes, but we suggest that some traits (vegetative plant height, stem dry matter content) should be omitted in studies involving mainly herbaceous species. Using the example of the relationship between leaf dry matter content and above-ground dead material, we demonstrate how the data collected may be used to analyse direct effects of climate and land use on ecosystem properties vs. indirect effects via changes in plant traits. CONCLUSIONS: This work shows the applicability of a set of protocols that can be widely applied to assess the impacts of global change drivers on species, communities and ecosystems.     

Pyrosequencing Reveals Changes in Soil Bacterial Communities after Conversion of Yungas Forests to Agriculture

The Southern Andean Yungas in Northwest Argentina constitute one of the main biodiversity hotspots in the world. Considerable changes in land use have taken place in this ecoregion, predominantly related to forest conversion to croplands, inducing losses in above-ground biodiversity and with potential impact on soil microbial communities. In this study, we used high-throughput pyrosequencing of the 16S ribosomal RNA gene to assess whether land-use change and time under agriculture affect the composition and diversity of soil bacterial communities. We selected two areas dedicated to sugarcane and soybean production, comprising both short- and long-term agricultural sites, and used the adjacent native forest soils as a reference. Land-use change altered the composition of bacterial communities, with differences between productive areas despite the similarities between both forests. At the phylum level, only Verrucomicrobia and Firmicutes changed in abundance after deforestation for sugarcane and soybean cropping, respectively. In cultivated soils, Verrucomicrobia decreased sharply (~80%), while Firmicutes were more abundant. Despite the fact that local diversity was increased in sugarcane systems and was not altered by soybean cropping, phylogenetic beta diversity declined along both chronosequences, evidencing a homogenization of soil bacterial communities over time. In spite of the detected alteration in composition and diversity, we found a core microbiome resistant to the disturbances caused by the conversion of forests to cultivated lands and few or none exclusive OTUs for each land-use type. The overall changes in the relative abundance of copiotrophic and oligotrophic taxa may have an impact in soil ecosystem functionality. However, communities with many taxa in common may also share many functional attributes, allowing to maintain at least some soil ecosystem services after forest conversion to croplands.     

流域土地利用变化对不同重现期洪水的影响——以奉化江皎口水库流域为例

土地利用变化对流域洪水过程产生显著影响,并导致设计洪水发生变化。为进一步指导流域防洪及水库洪水设计,以浙东沿海奉化江皎口水库流域为例,应用HEC-HMS水文模型模拟分析土地利用/覆被变化(LUCC)对不同重现期暴雨洪水事件的影响。结果表明,流域内1985—2003年土地利用变化引起不同重现期洪水过程与洪水量级发生改变,其中,洪量和洪峰均增加,洪量较洪峰变化明显。LUCC对小洪水过程影响更明显,5年一遇以上洪水的洪峰和洪量分别平均增加3%和7.6%,而小于2年一遇洪水的洪峰和洪量分别平均增加5.41%和11.91%。同时,LUCC使100年、50年和25年一遇洪水重现期分别提前了15、6a和2a,即其对量级最高的特大洪水的重现期影响最大。此外,不同的土地利用转变方式对洪水的影响程度不一,其中,林地向裸地转变对洪水影响最大,林地向灌草地转变次之,林地向耕地变化对洪水影响最小,且这种差异性在低重现期洪水表现更明显。     

Intermediate disturbance promotes diversity and the conservation of dung beetles (Scarabaeoidea: Scarabaeidae and Aphodiidae) in the Eastern Cape,South Africa

Environmental fluctuations, such as changes in climate, agricultural management and anthropogenic land-use patterns can affect the diversity of organisms inhabiting an area. Losses of biodiversity alter ecosystems processes, eroding their capacity to deliver ecosystem services. Dung beetles are critical ecosystem service providers, making them an ideal ecological indicator to explore the effects of land-use change on biodiversity. Dung beetles were sampled across three land-use types, in the summers of 2015 and 2016 in the Eastern Cape province, South Africa. Game ranching is regarded as a relatively low-intensity land use type. It was compared with cattle ranching (medium intensity) and dairy farming (high intensity) to examine their effect on dung beetle assemblage metrics (abundance, species richness and true Shannon diversity index), guild diversity (as nesting guilds) and spatial turnover. The intermediate grazing intensity of cattle ranching supported a higher abundance and diversity of both whole dung beetle assemblage and the nesting guilds, followed by the game ranches and then dairy farms. Differences between the sampling years were dependent on the beetle nesting guild, and largely correlated with rainfall and temperature. Cattle and game ranches shared a higher number of species than either shared with dairy farms. Whittaker's Beta-diversity index showed the highest species turnover between game ranches and dairy farms. A mix of game and cattle ranching, minimising dairy farming or restricting it to already ecological degraded sites, appears the best alternative for maintenance of dung beetle diversity and their ecosystem services. The year-to-year trends of the data were in general consistent, confirming that dung beetles are reliable ecological indicators; but also suggest that climate change that affects rainfall will result in the reduction of the abundance and diversity of this key ecological group.     

Are there links between responses of soil microbes and ecosystem functioning to elevated CO2, N deposition and warming? A global perspective

In recent years, there has been an increase in research to understand how global changes’ impacts on soil biota translate into altered ecosystem functioning. However, results vary between global change effects, soil taxa, and ecosystem processes studied, and a synthesis of relationships is lacking. Therefore, here we initiate such a synthesis to assess whether the effect size of global change drivers (elevated CO₂, N deposition, and warming) on soil microbial abundance is related with the effect size of these drivers on ecosystem functioning (plant biomass, soil C cycle, and soil N cycle) using meta‐analysis and structural equation modeling. For N deposition and warming, the global change effect size on soil microbes was positively associated with the global change effect size on ecosystem functioning, and these relationships were consistent across taxa and ecosystem processes. However, for elevated CO₂, such links were more taxon and ecosystem process specific. For example, fungal abundance responses to elevated CO₂ were positively correlated with those of plant biomass but negatively with those of the N cycle. Our results go beyond previous assessments of the sensitivity of soil microbes and ecosystem processes to global change, and demonstrate the existence of general links between the responses of soil microbial abundance and ecosystem functioning. Further we identify critical areas for future research, specifically altered precipitation, soil fauna, soil community composition, and litter decomposition, that are need to better quantify the ecosystem consequences of global change impacts on soil biodiversity.     

Large‐scale environmental flow results in mixed outcomes with short‐term benefits for a semi‐arid floodplain plant community

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A multi-modeling approach to evaluating climate and land use change impacts in a Great Lakes River Basin

River ecosystems are driven by linked physical, chemical, and biological subsystems, which operate over different temporal and spatial domains. This complexity increases uncertainty in ecological forecasts, and impedes preparation for the ecological consequences of climate change. We describe a recently developed “multi-modeling” system for ecological forecasting in a 7600 km² watershed in the North American Great Lakes Basin. Using a series of linked land cover, climate, hydrologic, hydraulic, thermal, loading, and biological response models, we examined how changes in both land cover and climate may interact to shape the habitat suitability of river segments for common sport fishes and alter patterns of biological integrity. In scenario-based modeling, both climate and land use change altered multiple ecosystem properties. Because water temperature has a controlling influence on species distributions, sport fishes were overall more sensitive to climate change than to land cover change. However, community-based biological integrity metrics were more sensitive to land use change than climate change; as were nutrient export rates. We discuss the implications of this result for regional preparations for climate change adaptation, and the extent to which the result may be constrained by our modeling methodology.     

Habitat Selection by African Buffalo (Syncerus caffer) in Response to Landscape-Level Fluctuations in Water Availability on Two Temporal Scales

Seasonal fluctuations in water availability cause predictable changes in the profitability of habitats in tropical ecosystems, and animals evolve adaptive behavioural and spatial responses to these fluctuations. However, stochastic changes in the distribution and abundance of surface water between years can alter resource availability at a landscape scale, causing shifts in animal behaviour. In the Okavango Delta, Botswana, a flood-pulsed ecosystem, the volume of water entering the system doubled between 2008 and 2009, creating a sudden change in the landscape. We used African buffalo (Syncerus caffer) to test the hypotheses that seasonal habitat selection would be related to water availability, that increased floodwater levels would decrease forage abundance and affect habitat selection, and that this would decrease buffalo resting time, reduce reproductive success and decrease body condition. Buffalo selected contrasting seasonal habitats, using habitats far from permanent water during the rainy season and seasonally-flooded habitats close to permanent water during the early and late flood seasons. The 2009 water increase reduced forage availability in seasonally-flooded habitats, removing a resource buffer used by the buffalo during the late flood season, when resources were most limited. In response, buffalo used drier habitats in 2009, although there was no significant change in the time spent moving or resting, or daily distance moved. While their reproductive success decreased in 2009, body condition increased. A protracted period of high water levels could prove detrimental to herbivores, especially to smaller-bodied species that require high quality forage. Stochastic annual fluctuations in water levels, predicted to increase as a result of anthropogenically-induced climate change, are likely to have substantial impacts on the functioning of water-driven tropical ecosystems, affecting environmental conditions within protected areas. Buffer zones around critical seasonal resources are essential to allow animals to engage in compensatory behavioural and spatial mechanisms in response to changing environmental conditions.     

Flood effects on invertebrates, sediments and particulate organic matter in the hyporheic zone of a gravel-bed stream

1. We investigated the effects of a flood on the fauna and physical habitat of the hyporheic zone of the Kye Burn, a fourth order gravel‐bed stream in New Zealand. 2. Freeze core hyporheic samples (to 50 cm depth) and benthic samples (to 10 cm) were taken, along with measurements of vertical hydrological gradient, before, 2 days after and 1 month after the flood (estimated return period: 1.5 years, estimated Q_max = 10.4 m³ s^?1). 3. The composition of the hyporheos differed over the three sampling occasions with fewer taxa collected immediately postflood than preflood. The equitability of the community was higher on both postflood occasions, consistent with the reduced densities of two abundant taxa (Leptophlebiidae and Copepoda). 4. Total invertebrate abundance was lower on the postflood occasions than preflood in both benthic (0–10 cm) and hyporheic (10–50 cm) sediments. Several taxa, including asellotan isopods and amphipods, recovered within 1 month of the event. Hyporheic densities of larval Hydora and nematodes did not differ among the three sampling occasions, but the water mite Pseudotryssaturus was more abundant 1 month after the flood than preflood. There was no evidence of vertical movements (to 50 cm) by any taxa in response to the flood. 5. The proportion of fine sediments (<1 mm) in the subsurface sediments (10–50 cm) increased over the three sampling occasions and median particle size declined, but sediment porosity did not change. More particulate organic matter was found in the sediments after the flood. 6. Our study provides little evidence that the hyporheic zone (to 50 cm) acted as a significant refuge during the flood event, although movements to or recolonisation from sediments deeper than 50 cm could explain the recovery of many crustacean and mite taxa within 1 month.     

Trait structure and redundancy determine sensitivity to disturbance in marine fish communities

Trait diversity is believed to influence ecosystem dynamics through links between organismal traits and ecosystem processes. Theory predicts that key traits and high trait redundancy—large species richness and abundance supporting the same traits—can buffer communities against environmental disturbances. While experiments and data from simple ecological systems lend support, large‐scale evidence from diverse, natural systems under major disturbance is lacking. Here, using long‐term data from both temperate (English Channel) and tropical (Seychelles Islands) fishes, we show that sensitivity to disturbance depends on communities’ initial trait structure and initial trait redundancy. In both ecosystems, we found that increasing dominance by climatically vulnerable traits (e.g., small, fast‐growing pelagics/corallivores) rendered fish communities more sensitive to environmental change, while communities with higher trait redundancy were more resistant. To our knowledge, this is the first study demonstrating the influence of trait structure and redundancy on community sensitivity over large temporal and spatial scales in natural systems. Our results exemplify a consistent link between biological structure and community sensitivity that may be transferable across ecosystems and taxa and could help anticipate future disturbance impacts on biodiversity and ecosystem functioning.     

Dominant control of climate variations over land-use change on net primary productivity under different urbanization intensities in Beijing,China

Climate variations and land-use change induced by rapid urbanization can lead to crucial impacts on ecosystem Net Primary Productivity (NPP), especially in regions with intensive human activity. However, the relative contributions of land-use change and climate variations to NPP changes under different urbanization intensities are still a topic of debate. This study reports on a case study in Beijing, which is undergoing rapid urbanization, to estimate the effects of land-use change and climate variations on NPP in regions with diverse urbanization intensities in recent decades using remote-sensing data and the Carnegie-Ames-Stanford Approach (CASA) model. The results reveal obvious land-use changes in Beijing, showing an increase in both built-up and forested areas in the two inner, highly urbanized regions and a dramatic conversion from built-up area and grassy bush to forest in the two outer, less urbanized regions. Factorial experiments were performed to estimate the contributions of land-use change and climate variations to NPP changes for different regions and land-use types. An increasing trend in regional NPP was observed with decreasing urbanization intensity in all experiments. However, the increment in NPP between 2002 and 2009 tended to decrease with decreasing urbanization intensity in most experiments. Climate variation was the dominant factor in increasing NPP in the study region during 2002–2009, with a mean contribution of ∼89.5% over different regions and land-use types. However, land-use change contributed to a certain extent to NPP changes for specific land-use types (e.g., ∼28.1% for forests) in regions of intensive urbanization. Eco-engineering approaches such as increasing vegetation cover, especially forest, in built-up areas and reforestation and afforestation in non-built-up areas may be useful in mitigating the impacts of urbanization on NPP, especially in intensively urbanized regions.     

基于B-IBI指数的温榆河生态健康评价

基于温榆河底栖动物和水质采样数据,采用底栖动物完整性指数(B-IBI)方法,进行温榆河生态健康评价,并探求河流水质与B-IBI指数的相关性。通过分布范围、判别能力以及相关性分析等,确定研究区B-IBI指标体系,包括总分类单元数、总生物量、优势分类单元个体相对丰度、敏感类群分类单元数、生物指数和粘附者个体丰度6个指标。根据参照点25%分位数确定温榆河底栖动物完整性评价标准,即B-IBI>1.821为健康,1.366—1.821为亚健康,0.910—1.366为一般,0.455—0.910为较差,0—0.455为极差。结果表明,温榆河27.3%河段处于健康状态,9.1%河段处于亚健康状态,13.6%河段处于一般状态,50%河段处于较差和极差状态。河流水质与B-IBI指数的相关系数为-0.549,表明生物指标作为水体评价的补充指标十分必要。     

Effects of a simulated upwelling event on the littoral epilithic diatom community of an ancient tropical lake (Lake Matano,Sulawesi Island,Indonesia)

Currently accepted paradigms in ecology dictate that disturbances at all temporal scales exert a significant influence on community structure and ecosystem stability. Microbial community resistance and resilience to perturbations are largely dependent on the physiological flexibility and taxonomic richness of the pre-perturbation community. Can a microbial community dominated by late-successional endemic taxa exhibit resistance and/or functional redundancy? In this study, intact littoral epilithic diatom communities from an ancient, tropical lake were exposed to oxygenated, filtered hypolimnetic water to simulate a lake upwelling event. Filtered lake surface water was used as a control. Discriminant function models based on changes in density and relative abundance of taxa after both treatments assigned samples to their correct treatment groups 100% of the time. A change in relative abundance of taxa between the two treatments indicated that competitive outcomes varied with a shift in the water chemistry, with different taxa exhibiting positive, negative, or neutral numerical responses. These results suggest that highly endemic diatom communities can maintain community function through shifts in competitive dynamics. We conclude that condition-specific competition models can be invoked to explain diatom community dynamics despite the inability of diatoms to use behavior to respond to changes in the abiotic environment.     

Flow‐related disturbances in forested and agricultural rivers: influences on benthic macroinvertebrates

Flow disturbances and conversions of land‐use types are two major factors that influence river ecosystems. However, few studies have considered their interactions and separated their individual effects on aquatic organisms. Using monthly monitoring data from two streams with different land‐use types (i.e. forest and agriculture) in the subtropical Central China over three years, we accurately predicted the changes of macroinvertebrate communities under flood disturbances and land‐use type conversions. The dominant taxa and main community metrics significantly declined following flash floods. Several mayflies and chironomid had rapid rates of recovery, which could reach high abundance in three months after floods. And most of the community metrics recovered more rapidly in the forested river than that in the agricultural river. Stepwise multiple regression (SMR) models were used to investigate the relationships between biotic metrics and hydrological and temporal variables. For example, SMR revealed that floods reduced the stability of benthic communities, and the length of low flow period was of considerable importance to the recovery of the fauna. Two‐way ANOVA indicated that intra‐annual fluctuation had more (e.g. the total abundance and wet biomass), equal (e.g. total richness, EPT richness, percent EPT abundance, and Margalef index), or less (e.g. tolerant value) influence on macroinvertebrate communities than land‐use types. Consequently, the effects of floods on macroinvertebrates should be taken into account when macroinvertebrates are used as indicators for assessing river ecosystem. (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Late holocene human impact on two coastal environments in New South Wales,Australia: a comparison of Aboriginal and European impacts

There are few historical analyses quantifying impacts of human activity in Australia. This paper compares vegetation change, fire regime, erosion and eutrophication rates between the European period and the recent prehistoric past in two lake systems on the south coast of New South Wales. The variance in pollen abundance and hence species population changes increased markedly in the historical period, especially amongst understorey taxa, and this could be related to changes in the local fire regimes and to the effects of grazing. Local fire activity decreased from the prehistorical period at both sites. Erosion rates increased in the historical period and both organic and inorganic components were deposited in the lakes. Erosion episodes could be related to fire during some periods but are clearly controlled by forest disturbance and land-use at other periods. The trophic status of the lakes was increasing from before European settlement but accelerated in the recent past. This was in part due to the increased erosion rates and in part due to fertiliser application. The results suggest that lower rates of erosional and eutrophic change occur in catchments with basaltic than with Holocene sand substrata.