Effects of water temperature on freshwater macroinvertebrates: a systematic review

Water temperature is one of the main abiotic factors affecting the structure and functioning of aquatic ecosystems and its alteration can have important effects on biological communities. Macroinvertebrates are excellent bio-indicators and have been used for decades to assess the status of aquatic ecosystems as a result of environmental stresses; however, their responses to temperature are poorly documented and have not been systematically evaluated. The aims of this review are: (i) to collate and summarize responses of freshwater macroinvertebrates to different temperature conditions, comparing the results of experimental and theoretical studies; (ii) to understand how the focus of research on the effects of temperature on macroinvertebrates has changed during the last 51 years; and (iii) to identify research gaps regarding temperature responses, ecosystem types, organism groups, spatiotemporal scales, and geographical regions to suggest possible research directions. We performed a comparative assessment of 223 publications that specifically consider freshwater macroinvertebrates and address the effects of temperature. Short-term studies performed in the laboratory and focusing on insects exposed to a range of temperatures dominated. Field studies were carried out mainly in Europe, at catchment scale and almost exclusively in rivers; they mainly investigated responses to water thermal regime at the community scale. The most frequent biological responses tested were growth rate, fecundity and the time and length of emergence, whereas ecological responses mainly involved composition, richness, and distribution. Thermal research on freshwater macroinvertebrates has undergone a shift since the 2000s when studies involving extended spatiotemporal scales and investigating the effects of global warming first appeared. In addition, recent studies have considered the effects of temperature at genetic and evolutionary scales. Our review revealed that the effects of temperature on macroinvertebrates are manifold with implications at different levels, from genes to communities. However, community-level physiological, phenological and fitness responses tested on individuals or populations should be studied in more detail given their macroecological effects are likely to be enhanced by climate warming. In addition, most field studies at regional scales have used air temperature as a proxy for water temperature; obtaining accurate water temperature data in future studies will be important to allow proper consideration of the spatial thermal heterogeneity of water bodies and any effects on macroinvertebrate distribution patterns. Finally, we found an uneven number of studies across different ecosystems and geographic areas, with lentic bodies and regions outside the West underrepresented. It will also be crucial to include macroinvertebrates of high-altitude and tropical areas in future work because these groups are most vulnerable to climate warming for multiple reasons. Further studies on temperature–macroinvertebrate relationships are needed to fill the current gaps and facilitate appropriate conservation strategies for freshwater ecosystems in an anthropogenic-driven era.     

Extinction debt of cities and ways to minimise their realisation: a focus on Melbourne

The formation and growth of cities sets in train a slow process of local species extinction, although it can take a long time for that extinction to be realised. Using Melbourne as an example, the authors ask ‘What plant species are potentially at risk and what strategies and actions could minimise the predicted negative outcomes?’     

基于全域连通性识别气候变化风险下的生物多样性保护优先区——以京津冀为例

在保护优先区规划中,有必要考虑气候变化的潜在风险并关注物种在气候驱动下的扩散格局。基于未来生物气候数据、地形多样性数据以及土地利用数据,应用Omniscape算法,对21世纪中叶(2040-2061年)气候变化情景下京津冀地区陆生哺乳动物的扩散进行全域连通性建模并与当前情景对比分析,识别出生物多样性保护优先区。结果表明:区域尺度下,气候变化风险使得高连通性的区域逐渐从平原向山区转移,分布趋于集中;斑块尺度下,林缘连通性较高,而位于林地或草地边缘的耕地连通性低。在此基础上,共识别生物多样性保护优先区共51786 km²,其中涵养区(占56.4%)在当前和未来的连通状况均较为良好;优化区(占38.4%)应提升生境质量以满足未来连通性的更高需求;而修复区(占5.22%)面临的气候变化风险较高,亟需进行生态修复以免在未来出现连通性夹点。本研究通过评估京津冀地区两种情景下的全域连通格局,为生物多样性保护的气候适应性规划提供了科学依据。     

Biodiversity responses to land‐use and restoration in a global biodiversity hotspot: Ant communities in Brazilian Cerrado

Given that land‐use change is the main cause of global biodiversity decline, there is widespread interest in adopting land‐use practices that maintain high levels of biodiversity, and in restoring degraded land that previously had high biodiversity value. In this study, we use ant taxonomic and functional diversity to examine the effects of different land uses (agriculture, pastoralism, silviculture and conservation) and restoration practices on Cerrado (Brazilian savanna) biodiversity. We also examine the extent to which ant diversity and composition can be explained by vegetation attributes that apply across the full land management spectrum. We surveyed vegetation attributes and ant communities in five replicate plots of each of 13 land‐use and restoration treatments, including two types of native vegetation as reference sites: cerrado sensu stricto and cerradão. Several land‐use and restoration treatments had comparable plot richness to that of the native reference habitats. Ant species and functional composition varied systematically among land‐use treatments following a gradient from open habitats such as agricultural fields to forested sites. Tree basal area and grass cover were the strongest predictors of ant species richness. Losses in ant diversity were higher in land‐use systems that transform vegetation structure. Among productive systems, therefore, uncleared pastures and old pine plantations had similar species composition to that occurring in cerrado sensu stricto. Restoration techniques currently applied to sites that were previously Cerrado have focused on returning tree cover, and have failed to restore ant communities typical of savanna. To improve restoration outcomes for Cerrado biodiversity, greater attention needs to be paid to the re‐establishment and maintenance of the grass layer, which requires frequent fire. At the broader scale, conservation planning in agricultural landscapes, should recognize the value of land‐use mosaics and the risks of homogenization.     

The Mediterranean Sea under siege: spatial overlap between marine biodiversity,cumulative threats and marine reserves

Aim A large body of knowledge exists on individual anthropogenic threats that have an impact on marine biodiversity in the Mediterranean Sea, although we know little about how these threats accumulate and interact to affect marine species and ecosystems. In this context, we aimed to identify the main areas where the interaction between marine biodiversity and threats is more pronounced and to assess their spatial overlap with current marine protected areas in the Mediterranean. Location Mediterranean Sea. Methods We first identified areas of high biodiversity of marine mammals, marine turtles, seabirds, fishes and commercial or well‐documented invertebrates. We mapped potential areas of high threat where multiple threats are occurring simultaneously. Finally we quantified the areas of conservation concern for biodiversity by looking at the spatial overlap between high biodiversity and high cumulative threats, and we assessed the overlap with protected areas. Results Our results show that areas with high marine biodiversity in the Mediterranean Sea are mainly located along the central and north shores, with lower values in the south‐eastern regions. Areas of potential high cumulative threats are widespread in both the western and eastern basins, with fewer areas located in the south‐eastern region. The interaction between areas of high biodiversity and threats for invertebrates, fishes and large animals in general (including large fishes, marine mammals, marine turtles and seabirds) is concentrated in the coastal areas of Spain, Gulf of Lions, north‐eastern Ligurian Sea, Adriatic Sea, Aegean Sea, south‐eastern Turkey and regions surrounding the Nile Delta and north‐west African coasts. Areas of concern are larger for marine mammal and seabird species. Main conclusions These areas may represent good candidates for further research, management and protection activities, since there is only a maximum 2% overlap between existing marine protected areas (which cover 5% of the Mediterranean Sea) and our predicted areas of conservation concern for biodiversity.     

A meta‐analysis of human disturbance impacts on Antarctic wildlife

Evidence‐based assessments are increasingly recognized as the best‐practice approach to determine appropriate conservation interventions, but such assessments of the impact of human disturbance on wildlife are rare. Human disturbance comprises anthropogenic activities that are typically non‐lethal, but may cause short‐ and/or longer‐term stress and fitness responses in wildlife. Expanding human activity in the Antarctic region is of particular concern because it increases the scope and potential for increased human disturbance to wildlife in a region that is often thought of as relatively untouched by anthropogenic influences. Here, we use a meta‐analytical approach to synthesise research on human disturbance to wildlife over the last three decades in the Antarctic and sub‐Antarctic region. We combine data from 62 studies across 21 species on the behavioural, physiological and population responses of wildlife to pedestrian, vehicle and research disturbances. The overall effect size indicated a small, albeit statistically significant negative effect of disturbance (?0.39; 95% CI: ?0.60 to ?0.18). Negative effects were found for both physiological and population responses, but no evidence was found for a significant impact on wildlife behavioural responses. Negative effects were found across pedestrian, vehicle and research disturbances. Significant and high among‐study heterogeneity was found in both disturbance and response sub‐groups. Among species, it remains unclear to what extent different forms of disturbance translate into negative population responses. Most current guidelines to limit wildlife disturbance impacts in Antarctica recommend that approaches be tailored to animal behavioural cues, but our work demonstrates that behavioural changes do not necessarily reflect more cryptic, and more deleterious impacts, such as changes in physiology. In consequence, we recommend that pedestrian approach guidelines in the Antarctic region be revisited. Due to the high heterogeneity in effects, management guidelines for different sites and species will need to be developed on a case‐by‐case basis, ideally in conjunction with carefully designed experiments. Guidelines to reduce the impact of research activities per se require development to reduce the potential impacts of conducting research. We identify research questions that, if answered, will further improve the evidence base for guidelines to manage human disturbance in Antarctica.     

Climatic stability in the Brazilian Cerrado: implications for biogeographical connections of South American savannas,species richness and conservation in a biodiversity hotspot

Aim To investigate the historical distribution of the Cerrado across Quaternary climatic fluctuations and to generate historical stability maps to test: (1) whether the ‘historical climate’ stability hypothesis explains squamate reptile richness in the Cerrado; and (2) the hypothesis of Pleistocene connections between savannas located north and south of Amazonia. Location The Cerrado, a savanna biome and a global biodiversity hotspot distributed mainly in central Brazil. Methods We generated occurrence datasets from 1000 presence points randomly selected from the entire distribution of the Cerrado, as determined by two spatial definitions. We modelled the potential Cerrado distribution by implementing a maximum‐entropy machine‐learning algorithm across four time projections: current, mid‐Holocene (6 ka), Last Glacial Maximum (LGM, 21 ka) and Last Interglacial (LIG, 120 ka). We generated historical stability maps (refugial areas) by overlapping presence/absence projections of all scenarios, and checked consistencies with qualitative comparisons with available fossil pollen records. We built a spatially explicit simultaneous autoregressive model to explore the relationship between current climate, climatic stability, and squamate species richness. Results Models predicted the LGM and LIG as the periods of narrowest and widest Cerrado distributions, respectively, and were largely corroborated by palynological evidence. We found evidence for two savanna corridors (eastern coastal during the LIG, and Andean during the LGM) and predicted a large refugial area in the north‐eastern Cerrado (Serra Geral de Goiás refugium). Variables related to climatic stability predicted squamate richness better than present climatic variables did. Main conclusions Our results indicate that Bolivian savannas should be included within the Cerrado range and that the Cerrado’s biogeographical counterparts are not Chaco and Caatinga but rather the disjunct savannas of the Guyana shield plateaus. Climatic stability is a good predictor of Cerrado squamate richness, and our stability maps could be used in future studies to test diversity patterns and genetic signatures of different taxonomic groups and as a higher‐order landscape biodiversity surrogate for conservation planning.     

A new species of Hyphessobrycon (Characiformes,Characidae) from the upper Rio Jequitinhonha basin,Minas Gerais,Brazil, with comments on morphological similarities with Stethaprioninae species from headwater environments

A new species of Hyphessobrycon is described from a marshland area in the headwaters of Rio Jequitinhonha basin, Minas Gerais, Brazil. The new species differs from congeners by presenting a single well-delimited conspicuous humeral blotch, rounded to vertically oval, restricted to the area dorsal to the lateral-line row of scales, without a narrower downward extension, greatest body depth anterior to dorsal-fin origin, bony processes in anal and pectoral-fin rays of males and four teeth in the inner row of the premaxillary bone. The new species presents a set of morphological features shared by some species currently assigned to Hasemania, Myxiops and to the Astyanax scabripinnis complex. Some of these features are discussed.     

High focus on threatened species and habitats may undermine biodiversity conservation: Evidence from the northern Baltic Sea

Conservation policies and environmental impact assessments commonly target threatened species and habitats. Nevertheless, macroecological research provides reasons why also common species should be considered. We investigate the consequences of focussing solely on legally protected species and habitats in a spatial conservation planning context using a comprehensive, benthic marine data set from the northern Baltic Sea. Using spatial prioritization and surrogacy analysis, we show that the common approach in conservation planning, where legally listed threatened species and habitats are the focus of conservation efforts, could lead to poor outcomes for common species (and therefore biodiversity as a whole), allowing them to decline in the future. If conservation efforts were aimed solely at threatened species, common species would experience a loss of 62% coverage. In contrast, if conservation plans were based only on common species, threatened species would suffer a loss of 1%. Threatened species are rare and their ecological niches distinct, making them poor surrogates for biodiversity. The best results are achieved by unified planning for all species and habitats. The minimal step towards acknowledging common species in conservation planning would be the inclusion of the richness of common species, complemented by information on indicator species or species of high importance for ecosystem functioning. The trade-off between planning for rare and common species should be evaluated, to minimize losses to biodiversity.     

中国保护区分类的研究

保护区是一个泛称,由于其建立的目的、要求和本身所具备的条件不同,所以具有多种多样的类型,不同类型管理的侧重点也有所区别.以保护区管理的目标为原则划分第一级分类单位,共有5个类型,即:严格的保护区、国家公园、保护景观、栖息地/物种管理区、资源管理保护区.再以保护对象原则划分第二、三级分类单位,共同构成一个完整的分类系统,以适应保护区事业日益发展的要求.     

Decline of unique Pontocaspian biodiversity in the Black Sea Basin: A review

The unique aquatic Pontocaspian (PC) biota of the Black Sea Basin (BSB) is in decline. The lack of detailed knowledge on the status and trends of species, populations, and communities hampers a thorough risk assessment and precludes effective conservation. This paper reviews PC biodiversity trends in the BSB (Bulgaria, Romania, Moldova, Ukraine, and Russia) using endemic mollusks as a model group. We aim to assess changes in PC habitats, community structure, and species distribution over the past century and to identify direct anthropogenic threats. The presence/absence data of target mollusk species were assembled from literature, reports, and personal observations. Pontocaspian biodiversity trends in the northwestern BSB coastal regions were established by comparing 20th‐ and 21st‐century occurrences. The direct drivers of habitat and biodiversity change were identified and documented. We found that a pronounced decline of PC species and communities is driven by (a) damming of rivers, (b) habitat modifications that disturbed previous natural salinity gradients and settings in the studied area, (c) pollution and eutrophication, (d) invasive alien species, and (e) climate change. Four out of the 10 studied regions, namely, the Danube Delta–Razim Lake system, Dniester Liman, Dnieper–Bug estuary, and Taganrog Bay–Don Delta, contain favorable ecological conditions for PC communities and still host threatened endemic PC mollusk species. Distribution data are incomplete, but the scale of deterioration of PC species and communities is evident from the assembled data, as are major direct threats. Pontocaspian biodiversity in the BSB is profoundly affected by human activities. Standardized observation and collection data as well as precise definition of PC biota and habitats are necessary for targeted conservation actions. This study will help to set the research and policy agenda required to improve data collection to accommodate effective conservation of the unique PC biota.     

Insights into the origin and distribution of biodiversity in the Brazilian Atlantic forest hot spot: a statistical phylogeographic study using a low-dispersal organism

The relative importance of the processes that generate and maintain biodiversity is a major and controversial topic in evolutionary biology with large implications for conservation management. The Atlantic Forest of Brazil, one of the world''s richest biodiversity hot spots, is severely damaged by human activities. To formulate an efficient conservation policy, a good understanding of spatial and temporal biodiversity patterns and their underlying evolutionary mechanisms is required. With this aim, we performed a comprehensive phylogeographic study using a low-dispersal organism, the land planarian species Cephaloflexa bergi (Platyhelminthes, Tricladida). Analysing multi-locus DNA sequence variation under the Approximate Bayesian Computation framework, we evaluated two scenarios proposed to explain the diversity of Southern Atlantic Forest (SAF) region. We found that most sampled localities harbour high levels of genetic diversity, with lineages sharing common ancestors that predate the Pleistocene. Remarkably, we detected the molecular hallmark of the isolation-by-distance effect and little evidence of a recent colonization of SAF localities; nevertheless, some populations might result from very recent secondary contacts. We conclude that extant SAF biodiversity originated and has been shaped by complex interactions between ancient geological events and more recent evolutionary processes, whereas Pleistocene climate changes had a minor influence in generating present-day diversity. We also demonstrate that land planarians are an advantageous biological model for making phylogeographic and, particularly, fine-scale evolutionary inferences, and propose appropriate conservation policies.     

Impacts of traditional land uses on biodiversity outside conservation areas: effects on dung beetle communities of Vaalbos National Park

Grazing is one of the key processes in terrestrial ecosystems and this can be provided by both indigenous and domestic ungulates. However, a question remains whether or not traditional forms of land use such as the grazing of domestic animals support the maintenance of biodiversity. If it does not, then the second question becomes to what extent does grazing of domestic animals alter the systems and processes that support biodiversity? This study demonstrates that in attempting to answer this question, small organisms like dung beetles are ideal indicators that can be used to express significant differences between conserved (indigenous) and non‐conserved (domestic) land. As a general trend, studies that investigated these differences displayed differences through analysis of the diversity indices. This method has in most cases demonstrated a lack of contrast between conserved and non‐conserved land. In the existence of such uncertainty this study has demonstrated that in such cases, where the analysis of biodiversity indices fail to demonstrate significant differences a closer examination of actual species such as guilds and functional groups could confirm significant differences between conserved and non‐conserved land. These apparently conflicting findings reflect the need to consider the actual elements of biodiversity (e.g. species) when assessing conservation issues rather than just the statistical measures of biodiversity.     

A multigene molecular assessment of cryptic biodiversity in the iconic freshwater blackfishes (Teleostei: Percichthyidae: Gadopsis) of south‐eastern Australia

Freshwater biodiversity is under ever increasing threat from human activities, and its conservation and management require a sound knowledge of species‐level taxonomy. Cryptic biodiversity is a common feature for aquatic systems, particularly in Australia, where recent genetic assessments suggest that the actual number of freshwater fish species may be considerably higher than currently listed. The freshwater blackfishes (genus Gadopsis) are an iconic group in south‐eastern Australia and, in combination with their broad, naturally divided distribution and biological attributes that might limit dispersal, as well as ongoing taxonomic uncertainty, they comprise an ideal study group for assessing cryptic biodiversity. We used a multigene molecular assessment including both nuclear (51 allozyme loci; two S7 introns) and matrilineal markers (cytb) to assess species boundaries and broad genetic substructure within freshwater blackfishes. Range‐wide examination demonstrates the presence of at least six candidate species across two nominal taxa, Gadopsis marmoratus and Gadopsis bispinosus. Phylogeographical patterns often aligned to purported biogeographical provinces but occasionally reflected more restricted and unexpected relationships. We highlight key issues with taxonomy, conservation, and management for a species group in a highly modified region. © 2014 The Linnean Society of London, Biological Journal of the Linnean Society, 2014, 111 , 521–540.     

Effect of host plant on the fitness of the spittlebug Notozulia entreriana: alternative method for rearing

Among the species belonging to 11 genera of Neotropical spittlebugs attacking graminaceous plants, Notozulia entreriana (Berg) (Hemiptera: Cercopidae) is one of the most important pests of grasses in several countries of South America. In this study, we evaluate the influence of three economically relevant species of host plants (Poaceae) on life-cycle traits of N. entreriana. We tested for differences in fitness responses (survival and fecundity) of insects on forage species which are frequent hosts for wild populations of spittlebugs. Comparison of life cycles on three host plants showed that only 2.5% of nymphs completed their development on Zea mays L., 22.5% on Chloris gayana Kunth, and 95% on Brachiaria decumbens Stapf. All the above suggests that C. gayana and B. decumbens are able to sustain complete development, behaving like natural hosts; the latter species is superior for artificial colonies because a shorter developmental period, higher survivorship in nymphs, and longer lifespan of adults were observed. Zea mays did not allow proper development, causing high mortality instead. We also developed a new approach for small-scale breeding of N. entreriana, which will enable subsequent biological and behavioral studies on this important pest species.     

Using a multi‐model ensemble approach to determine biodiversity hotspots with limited occurrence data in understudied areas: An example using freshwater mussels in México

Species distribution models (SDMs) are an increasingly important tool for conservation particularly for difficult‐to‐study locations and with understudied fauna. Our aims were to (1) use SDMs and ensemble SDMs to predict the distribution of freshwater mussels in the Pánuco River Basin in Central México; (2) determine habitat factors shaping freshwater mussel occurrence; and (3) use predicted occupancy across a range of taxa to identify freshwater mussel biodiversity hotspots to guide conservation and management. In the Pánuco River Basin, we modeled the distributions of 11 freshwater mussel species using an ensemble approach, wherein multiple SDM methodologies were combined to create a single ensemble map of predicted occupancy. A total of 621 species‐specific observations at 87 sites were used to create species‐specific ensembles. These predictive species ensembles were then combined to create local diversity hotspot maps. Precipitation during the warmest quarter, elevation, and mean temperature were consistently the most important discriminatory environmental variables among species, whereas land use had limited influence across all taxa. To the best of our knowledge, our study is the first freshwater mussel‐focused research to use an ensemble approach to determine species distribution and predict biodiversity hotspots. Our study can be used to guide not only current conservation efforts but also prioritize areas for future conservation and study.