Biodiversity and distribution patterns of freshwater invertebrates in farm ponds of a south-western French agricultural landscape

We assessed the importance for biodiversity of man-made farm ponds in an agricultural landscape in SW France lacking natural wetlands. The ponds were originally created to provide a variety of societal services (irrigation, visual amenity, water for cattle, etc.). We also assessed the environmental factors influencing invertebrate assemblages in these ponds. Only 18 invertebrate taxa out of 114 taxa occurring in the study area were common to ponds and rivers indicating that the contribution of farm ponds to freshwater biodiversity was potentially high. A Self-Organizing Map (SOM, neural network) was used to classify 36 farm ponds in terms of the 52 invertebrate families and genera they supported, and to specify the influence of environmental variables related to land-use and to pond characteristics on the assemblage patterns. The SOM trained with taxa occurrences showed five clusters of ponds, most taxa occurring only in 1–2 clusters of ponds. Abandoned ponds tended to support higher numbers of taxa, probably because they were allowed to undergo a natural succession. Nevertheless, abandoned ponds were also amongst the largest, so that it remained difficult to separate the effects of pond size and abandonment, although both factors were likely to interact to favour higher taxon richness. The invertebrate communities in the ponds appeared to be influenced mainly by widely acting environmental factors (e.g. area, regionalization of assemblages) with little evidence that pond use (e.g. cattle watering, amenity) generally influenced assemblage composition. Our results support the idea that agricultural landscapes containing man-made ponds make a significant contribution to freshwater biodiversity indicating that protection of farm ponds from threats such as in-filling and pollution can make a positive contribution to the maintenance of aquatic biodiversity. This added value for biodiversity should be considered when calculating the economic costs and benefits of constructing water bodies for human activities. Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. Guest editors: R. Céréghino, J. Biggs, B. Oertli & S. Declerck The ecology of European ponds: defining the characteristics of a neglected freshwater habitat     

A comparison of the catchment sizes of rivers,streams, ponds,ditches and lakes: implications for protecting aquatic biodiversity in an agricultural landscape

In this study we compared the biodiversity of five waterbody types (ditches, lakes, ponds, rivers and streams) within an agricultural study area in lowland England to assess their relative contribution to the plant and macroinvertebrate species richness and rarity of the region. We used a Geographical Information System (GIS) to compare the catchment areas and landuse composition for each of these waterbody types to assess the feasibility of deintensifying land to levels identified in the literature as acceptable for aquatic biota. Ponds supported the highest number of species and had the highest index of species rarity across the study area. Catchment areas associated with the different waterbody types differed significantly, with rivers having the largest average catchment sizes and ponds the smallest. The important contribution made to regional aquatic biodiversity by small waterbodies and in particular ponds, combined with their characteristically small catchment areas, means that they are amongst the most valuable, and potentially amongst the easiest, of waterbody types to protect. Given the limited area of land that may be available for the protection of aquatic biodiversity in agricultural landscapes, the deintensification of such small catchments (which can be termed microcatchments) could be an important addition to the measures used to protect aquatic biodiversity, enabling ‘pockets’ of high aquatic biodiversity to occur within working agricultural landscapes. Guest editors: R. Céréghino, J. Biggs, B. Oertli & S. Declerck The ecology of European ponds: defining the characteristics of a neglected freshwater habitat     

Urban ponds as an aquatic biodiversity resource in modified landscapes

Urbanization is a global process contributing to the loss and fragmentation of natural habitats. Many studies have focused on the biological response of terrestrial taxa and habitats to urbanization. However, little is known regarding the consequences of urbanization on freshwater habitats, especially small lentic systems. In this study, we examined aquatic macro‐invertebrate diversity (family and species level) and variation in community composition between 240 urban and 782 nonurban ponds distributed across the United Kingdom. Contrary to predictions, urban ponds supported similar numbers of invertebrate species and families compared to nonurban ponds. Similar gamma diversity was found between the two groups at both family and species taxonomic levels. The biological communities of urban ponds were markedly different to those of nonurban ponds, and the variability in urban pond community composition was greater than that in nonurban ponds, contrary to previous work showing homogenization of communities in urban areas. Positive spatial autocorrelation was recorded for urban and nonurban ponds at 0–50 km (distance between pond study sites) and negative spatial autocorrelation was observed at 100–150 km and was stronger in urban ponds in both cases. Ponds do not follow the same ecological patterns as terrestrial and lotic habitats (reduced taxonomic richness) in urban environments; in contrast, they support high taxonomic richness and contribute significantly to regional faunal diversity. Individual cities are complex structural mosaics which evolve over long periods of time and are managed in diverse ways. This facilitates the development of a wide range of environmental conditions and habitat niches in urban ponds which can promote greater heterogeneity between pond communities at larger scales. Ponds provide an opportunity for managers and environmental regulators to conserve and enhance freshwater biodiversity in urbanized landscapes whilst also facilitating key ecosystem services including storm water storage and water treatment.     

农田景观格局变化对昆虫的生态学效应

景观格局变化是全球变化的一个重要内容。农田是由人类赖以生存所种植的人工栽培作物组成的生态系统。在该景观系统中,多种植物-害虫-天敌相互作用、相互制约,形成有机整体。研究农田景观格局对害虫和天敌种群动态影响,不仅在害虫生物防治的实践中有重要意义,而且对于揭示人类活动对生物多样性结构与功能的影响,阐明农田景观中生物多样性整合、维持机理有重大的理论意义。本文从农田景观格局的"质、量、形、度"4个方面,系统地论述了农田景观格局变化对害虫和天敌的作用,分析了农田景观的生物控制服务功能,指出了未来研究发展的方向。     

Effects of environmental factors on the species composition of aquatic insects in irrigation ponds

Although irrigation ponds contribute to the conservation of aquatic biodiversity, they have experienced declines in recent years. We therefore examined the relationships between various environmental factors and the community composition of aquatic insects, specifically insect predators, in irrigation ponds to gain knowledge that would aid in the conservation and restoration of biodiversity. We selected Odonata, Hemiptera and Coleoptera as target taxonomic groups and conducted censuses of these groups in 21 ponds in Shiga, central Japan. In total, we collected 30 and 10 species (or species groups) of Odonata and Hemiptera, respectively, and 17 species of Coleoptera. A partial canonical correspondence analysis revealed that the following four environmental factors significantly affected the species composition of aquatic insect communities: the number of emergent plant species, percent concrete revetment, presence of litter and peripheral length. Among these variables, the number of emergent plant species was the most potent factor, perhaps because emergent plants serve as sites for oviposition and emergence, and provide refugia for aquatic insects (odonate nymphs in particular). In contrast, some species specifically inhabited sites poor in emergent plants. This study shows that reductions in concrete revetments are necessary for the conservation of biodiversity. This would lead to increases in the number of aquatic plant species, which provide habitats and oviposition sites for many aquatic insects. Furthermore, to enrich the local biodiversity of aquatic insects, groups of irrigation ponds with different environments are needed.     

Functional landscape heterogeneity and animal biodiversity in agricultural landscapes

Biodiversity in agricultural landscapes can be increased with conversion of some production lands into 'more-natural'- unmanaged or extensively managed - lands. However, it remains unknown to what extent biodiversity can be enhanced by altering landscape pattern without reducing agricultural production. We propose a framework for this problem, considering separately compositional heterogeneity (the number and proportions of different cover types) and configurational heterogeneity (the spatial arrangement of cover types). Cover type classification and mapping is based on species requirements, such as feeding and nesting, resulting in measures of 'functional landscape heterogeneity'. We then identify three important questions: does biodiversity increase with (1) increasing heterogeneity of the more-natural areas, (2) increasing compositional heterogeneity of production cover types and (3) increasing configurational heterogeneity of production cover types? We discuss approaches for addressing these questions. Such studies should have high priority because biodiversity protection globally depends increasingly on maintaining biodiversity in human-dominated landscapes.     

A new method to estimate aquatic invertebrate diversity in French shallow lakes and ponds

Shallow lakes and ponds are valuable ecosystems for conservation management. Aquatic invertebrates constitute a large proportion of diversity in these ecosystems, but their assessment is potentially time consuming and requires great expertise. The use of indicator taxa to estimate invertebrate diversity may resolve part of these difficulties. These indicators are rarely identified or their reliability is uncertain, i.e. they are based on partial inventories, neglecting groups with high diversity. In this study, invertebrate richness was assessed from 46 sites in France in various altitudinal, climatic, geological, human-impacted, and hydro-morphological contexts. Invertebrate identification was performed as accurately as possible in all taxonomic groups. Several potential indicators of diversity based on five key criteria were tested: strong direct correlation, identification facilities, strong cross-taxon congruence, low complementarity of the sampled habitats, and ubiquity for selected indicators. Three approaches were proposed to define these indicator groups: (1) a single taxonomic group as indicator, (2) a combination of targeted groups, and (3) a holistic inventory at low taxonomic resolution as a classical rapid assessment method for freshwater ecosystems. Results show that it is not recommended to use only one indicator group. The choice of several targeted groups could be a good intermediate solution but is not without bias. The rapid assessment inventory proposed is the most valuable method, and allows the estimation of invertebrate richness with a quasi-perfect correlation.     

The importance of blue and green landscape connectivity for biodiversity in urban ponds

The negative impact of urbanization on biodiversity can be buffered by blue (e.g., rivers, ponds) and green (e.g., parks, forests) spaces. However, to prevent biodiversity loss and reduce the risk of local extinctions, blue and green spaces need to be connected by corridors, so that organisms may disperse between sites. Landscape connectivity affects local community composition and metacommunity dynamics by facilitating dispersal. The goal of this study was to test the relative roles of pond environmental properties, spatial structure, and functional landscape connectivity on differentiation of invertebrate metacommunities in urban ponds in the city of Stockholm, Sweden. We characterized functional connectivity as blue connectivity (distance to water bodies), green connectivity (land use), and combined blue-green connectivity. We estimated functional connectivity by using electrical circuit theory to identify dispersal corridors. Interestingly, while circuit theory is often used in single-taxon studies, this method has rarely been applied to multiple taxa forming a metacommunity, as we have done in this study. Indeed, our study contributes toward an increased focus on the role of dispersal at the metacommunity level. We determined that functional connectivity was the most important factor in explaining community differentiation, with the local environment contributing comparatively little, and spatial structure the least. Combined blue-green functional connectivity had a major influence on structuring urban pond communities, explaining 7.8% of the variance in community composition across ponds. Furthermore, we found that increased functional connectivity was associated with an increase in the number of species. In summary, our results suggest that to preserve biodiversity in urban ponds, it is important to enhance functional connectivity, and that open green spaces could augment blue corridors in maintaining functional connectivity in urban pond metacommunities. To generalize these findings, future urban biodiversity studies should compare how functional connectivity affects metacommunities across multiple major cities.     

A pragmatic approach for improving invertebrate biodiversity assessment in the agricultural landscape

Assessments of invertebrate biodiversity in the agricultural landscape have been inconsistent and sometimes contradictory. There is a requirement to improve assessments, especially when quantifying the beneficial effects of low input and organic farming on biodiversity. To generate an improved understanding, data from four crops (organic leek, cabbage and broccoli, conventional calabrese), sampled in eastern England with both pitfall and pan traps, was used. Eight Orders, 55 ground beetle (Carabidae) species, 12 Coleoptera families and 66 Higher taxa (tribes, subfamilies and families) were used to calculate four diversity-related metrics and two fidelity metrics, using data from pitfall traps and from pitfall and pan traps combined. Diversity metrics were taxa richness, Shannon diversity index and Quantitative totals and indexes based on the number of each taxa recorded. Fidelity totals and indexes were used to assess deviations from the basic vegetable field habitat. Order was the least consistent taxa and the Shannon index was a poor diversity indicator. Taxa richness and Quantitative totals were more accurate and the use of quantifications based on the number of appropriate taxa recorded improved metric quality and Fidelity index was an improvement on the Fidelity total. In general, the highest metric values were in broccoli and cabbage, the crops with most weeds, and there were positive correlations between most metrics and weed cover. Metrics using combined epigeal and aerial invertebrate data, utilising the most taxa and the number recorded, were most appropriate for comparisons between crop types.     

Effects of biodiversity in agricultural landscapes on the protective microbiome of insects – a review

Symbiotic bacteria in herbivorous insects can have strong beneficial impacts on their host's survival, including conferring resistance to natural enemies such as parasitoid wasps or pathogens, while also imposing energetic costs on the host, resulting in cost‐benefit trade‐offs. Whether these trade‐offs favour the hosting of symbionts depends on the growth environment of the herbivore. Long‐term experimental grassland studies have shown that increasing plant species richness leads to an increased diversity of associated herbivores and their natural enemies. Such a change in natural enemy diversity, related to changes in plant diversity, could also drive changes in the community of symbionts hosted by the herbivorous insects. Aphids are one model system for studying symbionts in insects, and effects of host‐plant species and diversity on aphid‐symbiont interactions have been documented. Yet, we still understand little of the mechanisms underlying such effects. We review the current state of knowledge of how biodiversity can impact aphid‐symbiont communities and the underlying drivers. Then, we discuss this in the framework of sustainable agriculture, where increased plant biodiversity, in the form of wildflower strips, is used to recruit natural enemies to crop fields for their pest control services. Although aphid symbionts have the potential to reduce biological control effectiveness through conferring protection for the host insect, we discuss how increasing plant and natural enemy biodiversity can mitigate these effects and identify future research opportunities. Understanding how to promote beneficial interactions in ecological systems can help in the development of more sustainable agricultural management strategies.     

农业景观异质性对生物多样性与生态系统服务的影响研究进展

农业景观是人类生活所需资料的最主要来源地,农业景观及其提供的生物多样性和生态系统服务是影响人类福祉的最主要因素之一。系统梳理了景观异质性变化对生物多样性和生态系统服务影响的相关研究,总结指出:(1)农业景观格局变化会强烈的影响着区域生物多样性和生态系统服务,但总体上更关注了空间异质性,对于时间和功能异质性的研究仍需加强;(2)尺度效应、大尺度上景观背景的差异、种间差异、营养级联效应等会对景观异质性和生物多样性、生态系统服务间的关系产生显著的、综合的、交互的影响效应。未来区域农业景观中如何通过景观构建和管理措施的施行来确保生物多样性与生态系统服务供给的持续稳定仍需进一步加强以下内容的研究:景观异质性变化在时间上和功能上的影响效应及其阈值的探讨;跨尺度、多因素、多物种类群与多生态系统服务的综合及其交互作用;不同生物类群和不同生态系统服务间的权衡;景观异质性提高与有效生境面积下降及其引起的生物随机丧失间的权衡等问题。     

The contribution of standing waters to aquatic biodiversity: the case of water beetles in southeastern Iberia

The southeast of the Iberian Peninsula is a recognized area of high aquatic biodiversity, water beetles being one of the most well-known groups contributing to such biodiversity. The standing waters of this area show a high habitat diversity, occurring fresh, saline, temporary, permanent, karstic, endorheic, and artificial small water bodies. Despite this, there has been no attempt to analyze their contribution to local biodiversity. In this work, we identify the species inhabiting standing waters, analyze their contribution to the checklist from the study area, and recognize the species exclusive to this kind of habitat. We also highlight the most threatened species, identify the habitats which constitute biodiversity hotspots for this group, explore patterns of water beetle assemblage composition, and identify indicator species associated with each habitat type. We collected 125 species, 55 of them being typical to lentic habitats, in the set of 26 sampled standing water bodies, which means the 57% of the 218 species recorded in the most recent checklist for the study area. A total of 10 species are Iberian endemics and four can be considered threatened, Ochthebius irenae falling in both categories. Natural ponds showed the highest species richness (91 species), while saline water bodies (endorheic lagoons and continental salt-pans) contributed the most threatened species: Nebrioporus baeticus, Ochthebius delgadoi, Ochthebius tudmirensis and Ochthebius irenae. The most representative species for continental salt-pans was Ochthebius notabilis, for endorheic lagoons Ochthebius marinus and Hygrotus pallidulus, while Hydroglyphus geminus played this part in rice fields. Our results suggest that rice fields, endorheic lagoons, and continental salt-pans have specific water beetles assemblages, which could be used in bioassessment and conservation studies. In general, standing waters are seriously threatened in this area, particularly as a result of intensive agricultural activities. Thus, taking into account these ecosystems hold a high number of species, their continued degradation is likely to result in a significant loss of biodiversity, including key populations of a number of threatened and endemic species.     

Patterns of rare fish and aquatic insects in a southwestern French river catchment in relation to simple physical variables

Most of our current understanding of rarity has come from studies of terrestrial plants and animals, whereas freshwater habitats remain poorly documented under this topic. Here we considered the spatial distribution patterns of rarity at the river catchment scale, for five freshwater taxa (fish, Ephemeroptera, Plecoptera, Trichoptera and Coleoptera) in southwestern France. The data were collected at 554 and 155 sampling sites for fish and aquatic insects, respectively. General Linear Modelling was used to assess the influence of some typological variables (elevation, stream order, distance from source, and reach slope) on local numbers of rare species (restricted range). The relative numbers of rare species per taxa varied from 16% (Plecoptera) to 59% (Trichoptera). GLM chiefly yielded highly significant correlations between rarity and distance from the source and/or elevation for all taxa, showing that numbers of rare stream species increase towards downstream areas within the stream system. The spatial patterns in rarity for the different study taxa were rather concordant, probably as a result of similar responses to environmental conditions. By focusing on integrative variables, we emphasized the influence of river typology on the rarity of aquatic animals. Areas which carry rare species may concentrate an important fraction of the regional biodiversity. If end-users need geographic models (i.e. maps) to design river management frameworks, numerical patterning is needed to provide theoretical backgrounds: by predicting what the rarity should be like in a given area, we can provide explicit spatial schemes that may be useful to target further research, and to implement management options.     

Water quality of rural ponds in the extensive agricultural landscape of the Cerrado (Brazil)

The Brazilian Cerrado, one of the world’s 34 biodiversity hotspots, is today under increasing pressure from the intensification of agriculture, with the replacement of traditional extensive pastures by arable crops. Manmade ponds are currently widespread in rural areas of the Cerrado and provide many ecosystem services such as cattle watering, fish production, irrigation and erosion protection. As in other parts of the world, ponds are also likely to play a critical role in the conservation of freshwater biodiversity, although in the Cerrado there is still very little known about their biota. Good water quality, in particular the level of eutrophication, is a key factor in maintaining aquatic biodiversity at the regional scale. Therefore, we aimed here to assess the water quality of ponds in the Cerrado. We also assessed whether the main types of socioeconomic pond uses have an impact on their water quality. We focused on measures of primary production and conducted socioeconomic inquiries for 56 waterbodies in the Goiânia Cerrado region (GO, Brazil) at the beginning of the 2012 dry season. Overall, differences in water quality appeared to be linked to the type of pond use. The trophic level, as indicated by the chlorophyll concentration and conductivity, was greater in fish ponds and seemed to be related to management practices such as fish feeding and the type of water supply, in particular relatively low inflow volume. This contrasted with ponds used for cattle watering in extensive agricultural landscapes characterized by a low trophic level potentially beneficial for regional biodiversity. Good water quality in pasture ponds may be maintained by spring water inflow or heavy precipitation. Overall, the water quality of the Cerrado ponds was good compared with the same type of waterbodies in other regions of the world. These results highlight the high potential of the Cerrado ponds in extensive agricultural landscapes to provide an important habitat for aquatic biodiversity. Biodiversity inventories and assessments are now needed to increase our knowledge of these waterbodies and inform management activities at the local and regional scale.     

Relative importance of Conservation Reserve Programs to aquatic insect biodiversity in an agricultural watershed in the Midwest,USA

Hydrobiologia - The Conservation Reserve Program (CRP) and the Conservation Reserve Enhancement Program (CREP) in the USA offer farmers government financial incentives to take erosive agricultural...     

Habitat engineering by beaver benefits aquatic biodiversity and ecosystem processes in agricultural streams

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Diversity and distribution of aquatic insects in Southern Brazil wetlands: implications for biodiversity conservation in a Neotropical region

The selection of priority areas is an enormous challenge for biodiversity conservation. Some biogeographic methods have been used to identify the priority areas to conservation, and panbiogeography is one of them. This study aimed at the utilization of panbiogeographic tools, to identify the distribution patterns of aquatic insect genera, in wetland systems of an extensive area in the Neotropical region (approximately 280 000km2), and to compare the distribution of the biogeographic units identified by the aquatic insects, with the conservation units of Southern Brazil. We analyzed the distribution pattern of 82 genera distributed in four orders of aquatic insects (Diptera, Odonata, Ephemeroptera and Trichoptera) in Southern Brazil wetlands. Therefore, 32 biogeographic nodes corresponded to the priority areas for conservation of the aquatic insect diversity. Among this total, 13 were located in the Atlantic Rainforest, 16 in the Pampa and three amongst both biomes. The distribution of nodes showed that only 15% of the dispersion centers of insects were inserted in conservation units. The four priority areas pointed by node cluster criterion must be considered in further inclusions of areas for biodiversity conservation in Southern Brazil wetlands, since such areas present species from different ancestral biota. The inclusion of such areas into the conservation units would be a strong way to conserve the aquatic biodiversity in this region.