Article

Odonates as biological indicators of grazing effects on Canadian prairie wetlands

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Abstract

  1. Aquatic macro-invertebrates have frequently been used as biological indicators in lotic environments but much less commonly so in lentic habitats. Dragonflies and damselflies (Order Odonata) satisfy most selection criteria for lentic bioindicators of grazing impacts.2. Intensive cattle grazing affects most of the Canadian prairie pothole region but the effects of grazing on wetlands are poorly understood.3. Here the vegetation structure and invertebrate community composition of 27 prairie potholes in Alberta, Canada were studied and compared. Wetlands were evenly divided into three treatments of different grazing regimes.4. Removal of emergent vegetation by cattle grazing decreased odonate abundance and reproductive effort. Shorter Scirpus acutus stems resulted in significantly fewer damselflies (Suborder Zygoptera) and lower reproductive efforts.5. Overall odonate diversity was affected by the height of key plant species, highlighting the importance of the vegetation structure of both emergent vegetation for breeding and adjacent upland vegetation for nocturnal roosts. Wetland vegetation structure was more important than vegetation composition to the life history of odonates.6. Wetland water quality parameters of nitrogen, phosphorus, total dissolved solids (TDS), and chlorophyll-a concentration did not change due to the presence of grazing cattle at wetlands so water quality influences were rejected as mechanisms of change.7. Larval odonate diversity and abundance was positively correlated with overall aquatic macro-invertebrate diversity and abundance, hence it was concluded that the larval odonate community can be an accurate bioindicator of intactness and diversity of overall aquatic macro-invertebrate communities in Canadian prairie wetlands.

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... Hydrology is considered one of the most important factors in the capacity to manage wetland vegetation and diversity (Ma et al., 2010); thus wetlands often have systems in place to manipulate water levels. Water control structures (Gray et al., 1999) allow for flooding or drawdown of water in wetlands to mimic their dynamic water regimes (USDOI, 2000;Foote and Rice Hornung, 2005). Seasonally and interannually dynamic water regimes promote wetland plant establishment and growth and diversify habitats for aquatic invertebrates (Ma et al., 2010;Collins et al., 2015). ...
... In river systems that are unaltered by humans, riparian wetlands are dynamic because of periodic flooding events, some of which can be substantial and seasonally sustained (Mitsch et al., 2005;Mitsch and Gosselink, 2007). Flooding provides the transfer of nutrients and organisms that allow wetlands to diversify, while seasonal drying of the floodplain enables plant growth and provides food and habitat for invertebrates and other organisms (USDOI, 2000;Foote and Rice Hornung, 2005;Lyon et al., 2010;Conallin et al., 2016). However, in highly modified riparian systems used for transportation and flood reduction, historic flood and drought conditions have been removed, breaking the critical link between the energy-rich flood waters and nearby wetlands (Vannote et al., 1980). ...
... Invertebrates can serve as an indicator for wetland restoration and management success because they are the trophic foundation food for other organisms. In addition to measuring plant and vertebrate response, surveys of invertebrates provide opportunity to refine wetland management techniques because invertebrates are often habitat specific and sensitive to environmental perturbations (Foote and Rice Hornung, 2005;Suren et al., 2011;Collins et al., 2015). ...
Article
We investigated how water management and other covariates affected aquatic macroinvertebrate density and diversity of wetlands in the Montezuma Wetlands Complex (MWC) of the Lake Ontario watershed, New York, USA. We conducted aquatic macroinvertebrate sampling during May–July in 2016–2018 to coincide with when juvenile wetland birds require these protein foods. Models that best explained aquatic macroinvertebrate density and taxon richness included water drawdown treatment, water depth, and water drawdown treatment from the prior year. Predicted mean density of aquatic macroinvertebrates was 117.2% greater in partial drawdown than passive wetlands (i.e., wetlands without active water removal) and increased by 516.2% with 15.5–48 cm increase in water depth. Density of aquatic macroinvertebrates also was ≥ 2.6 times greater in wetlands with a full drawdown the year prior. Taxon richness and Shannon Wiener Diversity Index (H′) varied positively with water depth, and there was greater diversity in partial drawdown than passive wetlands. Taxon richness was nearly 2 times greater in areas with full drawdown the year prior than those with partial drawdowns and passive wetlands. Other competing models for H′ also included negative effects of percentage monotypic cattail and invasive plant taxa. These findings are consistent with aquatic macroinvertebrate adaptation to dynamic wetland hydrology, and we recommend that managers actively manipulate hydrology to provide abundant and diverse food resources for birds at managed wetlands in the Great Lakes region.
... Dragonflies (Insecta: Odonata) can be effective indicators of habitat integrity (Chovanec & Waringer, 2001;Golfieri, Hardersen, Maiolini, & Surian, 2016;Oertli, 2008;Oliviera-Júnior et al., 2015;Renner, Sahlén, & Périco, 2016;Silva, De Marco, & Resende, 2010), making them useful for questions in applied ecology and conservation biology (Bried & Samways, 2015;Córdoba-Aquilar, 2008;Villalobos-Jiménez, Dunn, & Hassall, 2016). With aquatic larvae and terrestrial adults, their abundance and diversity is usually greater in intact, heterogeneous, natural ecosystems that contain ponds, streams, lakes, forests, and meadows than in simplified, human-altered landscapes (Dolný & Harabiš, 2012;Foote & Rice Hornung, 2005;Kayoda, Suda, Nishihiro, & Washitani, 2008;Luke et al., 2017;Remsburg, 2007;Remsburg & Turner, 2009;Sahlén and Ekestubbe, 2001). Although many species are fairly tolerant of waterborne pollutants -one (Brachymesia contaminata (Fabricius)) is even an indicator species of contaminated *Corresponding author: Email: wade.worthen@furman.edu ...
... For example, the density of Aeshna viridis L. larvae -an endangered species that uses only one host plant (Stratiotes aloides) which is declining across Europe -correlates with patch size of the host plant on a scale of 1-100 m 2 (Suhonen, Suutari, Kaunisto, & Krams, 2013). Remsburg and Turner (2009) found that the abundance or species richness of odonate larvae and adults were positively affected by the presence of aquatic macrophytes and tall riparian plants in m 2 plots, and Foote and Rice Hornung (2005) found that dragonfly diversity declined with a decline in the height of both aquatic vegetation (for emergence) and upland vegetation (for roost sites) caused by cattle trampling around prairie potholes. Other parameters that affect the abundance and composition of adult dragonfly communities on a small scale include the type and heterogeneity of aquatic and terrestrial vegetation (Goertzen & Suhling, 2013;Niba & Samways, 2006;Schindler, Fesl, & Chovanec, 2003), the presence of detritus (Brasil, Batista, Giehl, Valadão, Santos, & Dias-Silva, 2014), and light availability (Clark & Samways, 1996;Remsburg, Olson, & Samways, 2008). ...
... We surveyed odonates three times at each plot from June to August 2017, between 1100 h and 1400 h, in accordance with the minimum survey recommendations of Foote and Rice Hornung (2005) and Chovanec, Schindler, Waringer, and Wimmer (2015). During each survey, we counted the number of dragonflies of each species that perched within a subplot during a three-minute observation period. ...
Article
Dragonflies (Insecta: Odonata) use both aquatic and terrestrial ecosystems, and the abundance and diversity of odonates should be good indicators of habitat integrity. To determine which environmental variables affect odonates, we sampled adult dragonflies three times at 12 sites in Pickens and Greenville Counties, SC, USA, in different habitats, at different spatial scales, across a landscape gradient from intact forest to urban locations. At each site, we established two 2 m × 20 m plots along the shoreline of each aquatic habitat. We sampled dragonflies in ten 2 m × 2 m subplots/plot, described the vegetation and substrate in these subplots and adjacent aquatic subplots, and measured the percent cover of different landforms within 500 m of each plot center. Using nested ANOVA and Akaike information criteria models, habitat type and correlating environmental variables (substrate type and bank vegetation) were the best predictors of community structure at all spatial scales. Streams and rivers had fewer individuals and species than lakes, and had a nested subset of species found in lake communities. Landscape elements were also important, with indices declining as barren land and grasslands increased. At the largest scale, anthropogenic changes to the landscape had mixed effects. Small habitats isolated in urban areas had a significantly depauperate, nested subset of species found in communities inhabiting larger natural areas. However, odonate abundance and diversity was highest at human-made lakes and ponds, suggesting that these anthropogenic features help maintain odonate communities.
... The extent to which physical vegetation management affects animal communities has been examined in many studies with varying results due to complicated and nonlinear responses. Previous studies have reported that intense physical vegetation management on terrestrial and aquatic environments reduced the abundance and diversity of macroinvertebrate predators (Foote and Hornung 2005;Hsu et al. 2011;Briggs et al. 2019;Chien et al. 2019), waterfowl (Fleming et al. 2015;Ramachandran et al. 2017) and small freshwater fish (Knorp and Dorn 2016). On the contrary, other studies have revealed that a reduction of aquatic vegetation coverage to a medium level raised the density and species richness of certain groups of animals, such as predatory fish (Miranda and Hodges 2000;Cunha et al. 2019). ...
... Nagy et al. (2019) discovered that the diversity of adult damselflies decreased when macrovegetation coverage increased. On the contrary, it might have a neutral or even negative effect on adult abundance and diversity when riparian vegetation height exceeded 80 cm (Foote and Hornung 2005). Previous research also mentioned that tall shore vegetation, emergent aquatic plants and pond area size were critical factors for maintaining high diversity of Odonata adults (Johansson et al. 2019). ...
... However, our results indicated that management imposed on both terrestrial and aquatic vegetation did not show a clear effect on adult abundance and species richness. Our results are not consistent with previous studies which demonstrated significant positive effects from riparian vegetation on adult diversity and abundance (Foote and Hornung 2005;Remsburg and Turner 2009;Giuliano and Bogliani 2019). This inconsistency might be because of different geographical scales and the high adaptation of adults in urban areas. ...
Article
Physical vegetation management has shown deep and diverse impacts on fauna diversity and abundance. However, it is still unclear to what degree management influences Odonata (dragonfly and damselfly) in urbanized ecosystems. In order to understand the crucial factors among Odonata (adults and larvae) and physical vegetation management in a highly urbanized environment, this study investigated the response of Odonata abundance and species richness to riparian and emergent aquatic vegetation management in artificial ponds. Our results showed that physical management of emergent macrophytes did have a significant effect on larval abundance. However, adult abundance and species richness did not show clear differences between different levels of riparian vegetation coverage. Water temperature, water pH value and the presence of emergent macrophytes were also crucial drivers of larval abundance though macrophytes had a stronger effect as compared to water quality. Overall, this study highlights the importance of marginal vegetation, especially emergent macrophytes, in highly urbanized environments. Our study suggests key management considerations for plant management in urban ponds which, when implemented, would work to enhance Odonata population and overall ecological value of artificial wetlands in cities.
... Several studies have shown that macroinvertebrate diversity in temporary wetlands located in protected areas such as national parks is generally high compared to areas exposed to agricultural activities (Chawaka et al., 2018;Dalu and Chauke, 2020;Dube et al., 2020). For example, dragonflies and damselflies (Odonata) larvae have shown to be good biological indicators of grazing impacts on wetlands (Lee Foote and Rice Hornung, 2005). The removal of emergent vegetation by grazers decreased odonate abundance and reproductive effort in the Prairie wetlands (Kostecke et al., 2005;Lee Foote and Rice Hornung, 2005). ...
... For example, dragonflies and damselflies (Odonata) larvae have shown to be good biological indicators of grazing impacts on wetlands (Lee Foote and Rice Hornung, 2005). The removal of emergent vegetation by grazers decreased odonate abundance and reproductive effort in the Prairie wetlands (Kostecke et al., 2005;Lee Foote and Rice Hornung, 2005). Empididae and Mystacides, were also identified as indicator taxa of early grazed temporary wetlands, north of Strathmore, Alberta (Silver and Vamosi, 2012). ...
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This chapter introduces the diversity and community composition of macroinvertebrates occurring in wetlands with emphasis on the permanent and temporary wetlands in the Afrotropical region of the world. The chapter explores factors shaping the composition of macroinvertebrate communities of the permanent and temporary habitats, and the structuring role of dispersal mechanisms. The diversity and composition of macroinvertebrates is contrasted between different regions of the world and between permanent and temporary wetland types. Furthermore, the role of macroinvertebrates as indicators of habitat quality, ecosystem functions, and services provided by macroinvertebrates in wetlands is explored. Finally, the threats to macroinvertebrates in wetlands are highlighted.
... known that adults follow visual cues to detect breeding habitats, and that shorter and scarcer littoral vegetation can be perceived as lower habitat quality, affecting Odonata oviposition and reproduction (Lee Foote and Hornung 2005;Raebel et al. 2012). Furthermore, because dragonflies and particularly damselflies rely on aquatic vegetation for oviposition (Corbet 1980), declines observed in larval odonate richness have been linked to trampling and removal of vegetation from the littoral zone that can interrupt odonate emergence (Lee Foote and Hornung 2005). ...
... known that adults follow visual cues to detect breeding habitats, and that shorter and scarcer littoral vegetation can be perceived as lower habitat quality, affecting Odonata oviposition and reproduction (Lee Foote and Hornung 2005;Raebel et al. 2012). Furthermore, because dragonflies and particularly damselflies rely on aquatic vegetation for oviposition (Corbet 1980), declines observed in larval odonate richness have been linked to trampling and removal of vegetation from the littoral zone that can interrupt odonate emergence (Lee Foote and Hornung 2005). SEM analysis showed indirect negative effect of non-native ungulates on larval Odonates, mediated by a reduction in vegetation height (Fisher's C = 6.975, df = 12, P = 0.871; Fig. 2). ...
Article
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Herbivory by non-native species can create strong direct and indirect effects on plant and arthropods communities that can potentially cross ecosystem boundaries. Yet, the cross-ecosystems impacts of non-native species are poorly understood. We took advantage of ongoing invasions by non-native ungulates in Patagonia, Argentina, to examine their cross-ecosystem impacts on water parameters, littoral vegetation and aquatic macroinvertebrate assemblages in wetlands. We found a gradient of invasion by non-native ungulates from intact (non-invaded) to highly invaded wetlands. These highly invaded wetlands had ~ 24% less vegetation cover, which was 72% shorter in height than vegetation in intact wetlands. As a result, the abundance of predatory macroinvertebrates such as Odonata (dragonflies) was reduced by ~ 90%; while Diptera were ~ 170% more abundant, and Oligochaeta were recorded mostly at invaded sites. In contrast, we did not find evidence that non-native ungulates altered water parameters. Understanding the indirect consequences of invasive non-native species is crucial for quantifying the real impacts of global change. Our results show strong cross-ecosystem impacts of non-native ungulates on macroinvertebrate wetland communities, highlighting the importance of indirect interactions beyond ecosystem boundaries.
... Dragonflies are distributed irregularly on the stream [54], being more frequent in areas with resources, for example, places with spots of light (formed by holes in the dense riparian forest) [51], areas with perches [55] or specific substrates for oviposition [31]. However, despite this kind of distribution and the natural environmental variation found in aquatic systems, the 100 m stretch assessment at the streams was efficient, as we did not find significant differences in species composition in bigger transects. ...
... However, we believe this type of standardization per individual might not be very efficient for Odonata since the observed abundance in each water body is not high enough. Another problem is that Odonata often has a clustered distribution [55], which would probably affect standardization through abundance. ...
Article
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Odonata can be sampled following different types of protocols. In Brazil, the most used protocol is the scanning in fixed areas method, where a 100-meter transect is delimited in one of the stream margins, subdivided into 20 segments measuring 5 meters. Despite being universally used, the methodological efficiency or limitations of this protocol for Odonata has never been tested. In this scenario, our objective was to assess the efficiency of the sampling protocol to measure the richness and composition of Odonata in three fundamental aspects: the time of sampling and sampling effort over time and space. We show that the best sampling efficiency was achieved in collections performed at noon, in transects measuring 100 meters, requiring at least two samplings in the same location, supporting the procedures traditionally adopted by many studies with the group. While comparing species composition, we did not see any implication between the different treatments on the capture of the local species pool. However, we highlight and discuss some possible methodological flaws when using this protocol to sample specific Odonata groups. We believe the results obtained are fundamental in the inventory of species and to conduct future studies, as well as to aid conservative measures that use the order Odonata as a tool for environmental monitoring.
... A significant negative correlation exists between cattle grazing and Odonata species richness in wetlands. Due to excessive use of agrochemicals the abundance of dragonflies in rice fields is decreasing and the farmers claimed occurrence of dragonflies in low number in their rice fields could be those used to graze their cattle on harvested rice straw in rice fields and also overused the agrochemicals (Clark and Samways, 1996;Samways et al., 1996;Takamura, Results and Discussion Section 1 1996;Stewart and Samways, 1998;Westfall and May, 1999;Hornung and Rice, 2003;Foote and Hornung, 2005). ...
... to evaluate environmental quality producing comparable results to disturbances both at small and large spatial scales. On the basis of these features they are considered as very useful group of animals for habitat assessment and biodiversity monitoring (Stewart and Samways, 1998;Andreas and Johann, 2001;Jakab et al., 2002;Bried and Ervin, 2005;Catling, 2005;Foote and Hornung, 2005;Jenny, 2007;Sato and Riddiford, 2008). They are also considered as keystone taxa because of their controlling influence on the trophic interactions (Bambaradeniya et al., 2004). ...
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In this study, factors regarding the excessive use of pesticides and those particularly involved in the cultivation of high input and low input rice crop were investigated. Farmers’ sources of Basmati rice seed acquisition and perception of pest insects’ incidence and their management practices in rice crop were also evaluated. Results indicated that the main reason for farmers’ adoption of high input rice farming was to get better yields and profit. The main sources of rice seed acquisition were the home retained, local market and seed companies. Farmers were well aware of major pest insects of rice and reported moderate incidence of rice stem borers and high incidence of rice leaffolder but little was known about natural enemies and diseases. The most common reason for excessive use of insecticides was the misconception that pesticides were necessary to increase the yield. Farmers still relied to a great extent on chemicals to control the pests in rice crop and majority of them ignored economic threshold levels (ETL) recommended for the control. But the effective and economic suppression of insect pests in rice ecosystem by the judicial use of pesticides on the basis of ETL is utmost essential. Therefore, ETLs for the chemical control of rice stem borers (Scirpophaga incertulus Wlk. & S. innotata Wlk.) and rice leaffolder (Cnaphalocrosis medinalis Gn.) in the traditional Basmati rice growing area, the Kallar tract were also determined to be 5% dead-hearts (DH) and 3% folded leaves for stem borers and rice leaffolder respectively. The use of insecticides ignoring recommended ETLs along with higher doses of fertilizers is not only the cause of economic losses but also harmful to the insect biodiversity. So the effect of high inputs (HIP) farming practices on insect communities was also investigated. The higher number of species richness and abundance were measured for low input (LIP) systems. On the other hand some insects were abundant in HIP systems because of their adaptation to such kind of habitat. The insect species richness and abundance increased with rice crop age and showed close relationship with crop. All the major trophic guilds, except non rice pest (NRP), were also in abundance for LIP systems. Some species of insect were found sensitive to agrochemical pollution and were regarded as bioindicators. The higher Shannon’s value in some cases for HIP farms suggested that agrochemicals had a significant impact in eliminating the rare species and hence increased the Shannon’s and evenness values among the species. The overall effect of HIP rice farming on insect species richness and abundance was significantly negative. The LIP systems were found having greater diversity along with supporting a good number of rare species.
... The main wetland characteristics promoting a diverse odonate community were heterogenic vegetation and relatively high water transparency. This is in line with multiple previous studies showing positive relationships between diverse aquatic vegetation, abundance, and species richness of Odonata (Lenz, 1991;Clark & Samways, 1996;Stewart & Samways, 1998;Foote & Rice Hornung, 2005;Remsburg & Turner, 2009;Mabry & Dettman, 2010;Balzan, 2012;Pires et al., 2014;Janssen et al., 2018), as well as the importance of appropriate water quality for odonate diversity (Lenz, 1991;Vanacker et al., 2018). ...
... Although these wetlands supported mainly generalists, these common species are often very important to ecosystem functioning, and should be valued and supported alike (Gaston, 2010). Since Odonata are an important link in aquatic food webs (Wissinger, 1999;Corbet, 2004;Hornung & Foote, 2006), their presence may indicate the occurrence of other fauna, such as other invertebrates (Briers & Biggs, 2003;Foote & Rice Hornung, 2005) and waterfowl (Hornung & Foote, 2006;Patra et al., 2010;Horváth et al., 2012). Thus, further research on other taxa, such as amphibians and other macroinvertebrates, would be welcome to increase our knowledge of biodiversity in constructed agricultural wetlands. ...
... The present study was designed to determine the effect of water quality on a group of aquatic macroinvertebrates in stormwater ponds, Odonata, which are recognized bioindicators of wetland ecosystems (Briers and Biggs, 2003;Foote and Rice Hornung, 2005;Kutcher and Bried, 2014). We focused on the aquatic life stage of Odonata including dragonflies (Anisoptera) and damselflies (Zygoptera). ...
Article
Cities are increasingly using constructed ponds to mitigate flooding and downstream water pollution from urban runoff. As a result, these stormwater ponds can have poor water quality, yet they can also attract wildlife. In this study, the effects of water quality on dragonflies and damselflies (Odonata) were determined in stormwater ponds (n = 41) and natural reference ponds (n = 10) of similar size across the National Capital Region of Canada. A total of 38 chemical/physical water quality variables along with Odonata nymph abundance and taxonomic composition were sampled at each pond. Chloride concentrations exceeded the guideline for the protection of aquatic life at over two-thirds of the stormwater ponds. Among all the metals tested, only Cu exceeded guidelines at many stormwater ponds. Both dragonfly and damselfly nymphs were on average less abundant in the stormwater ponds in comparison to the natural ponds. Ponds with high concentrations of chloride and metals typically had lower dragonfly abundance. Dragonfly community structure was significantly influenced by high chloride (or conductivity), which likely originates from winter road salting. In contrast, damselfly community structure in the stormwater ponds was similar to that found in natural ponds, with nutrients and metals explaining a small percent of variation in community structure. A water quality index developed to assess habitats for the protection of aquatic life did not significantly explain Odonata abundance or measures of diversity and may not be suitable in assessing pond habitat quality. To improve pond habitats within cities, efforts should be directed at reducing the amount of impervious surface and road salt usage within catchment basins.
... The habitat heterogeneity hypothesis proposes that more heterogeneous habitat provides greater multidimensional niche space that can hold a higher diversity and abundance of organisms (MacArthur and MacArthur 1961). This scenario was found in the Forested Habitat, with its greater structural diversity in riparian vegetation that helps maintain high Odonata population sizes, because it affords greater protection against predators (Braccia et al. 2007;Luke et al. 2017;Raebel et al. 2012), a greater variety of prey and hunting habitats (perches) (Foote and Hornung 2005), and mating and oviposition sites (Corbet 1999). The more favorable conditions offered by the Forested Habitat are linked to a greater survival rates, life expectancy and odds of recapture in this Odonata population (Tables 1, 2). ...
Article
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Land use change, notably the conversion of natural habitats into agriculture, has strong negative effects on wild animal populations. Effects of disturbance and seasonality on demographic parameters of the damselfly Mesamphiagrion laterale Selys, 1876 were assessed to investigate how individual survival probability and over population size changed according to season and anthropogenic disturbance (agricultural habitat vs. forested habitat). For each habitat type, forest cover, area covered by vegetation, percentage of macrophytes and water physicochemical attributes were measured. Likewise, population parameters such as sex ratio, population size, life expectancy, survival and recapture rates were estimated using Cormark-Jolly-Seber (CJ-S) models. Life expectancy of the total population was lower during the rainy season, while population size and survival in males were lower in agricultural habitats during this same season. Human activities related to agriculture and livestock production in the Colombian Andes threaten the long-term viability of odonate populations through degradation of aquatic habitats. Contrary to our initially proposed hypotheses, these effects were more intense for males due to their closer association with riparian vegetation and thus greater exposure to aquatic pollutants.
... Data on the composition of littoral aquatic vegetation of the studied man-made water bodies are available, but were not considered since most Odonata species generally show little response to particular plant species (terrestrial or aquatic) (e.g. Foote and Hornung, 2005), and their abundance is often positively correlated with the local abundance of vegetation (as reviewed in Remsburg, 2007). Macrophyte structure and abundance are negatively affected by an increase of water level fluctuations (van Geest et al., 2005). ...
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Many studies have reported a negative impact of freshwater habitat modification on biota. Nevertheless, some man-made water bodies have proven to be valuable for biodiversity conservation as they can harbour many species. We investigated 36 man-made water bodies to determine their suitability as habitats for Odonata. Larvae were sampled in littoral, during the summer months of 2016 and 2017. At each sampling site, ten samples were collected using a benthos hand net. A total of 21 Odonata species was recorded. Odonata assemblages mainly consisted of common widespread species. Yet, at Vlačine Reservoir, located in the Dinaric Western Balkan ecoregion, we also recorded a rare and endangered Mediterranean species, Lindenia tetraphylla (Vander Linden, 1825). Aquatic and riparian vegetation, water level fluctuations and dissolved oxygen concentration had the highest influence on Odonata, showing that man-made water bodies with a well-developed riparian zone and aquatic vegetation, and with low daily and seasonal water level fluctuations, can provide suitable habitats for diverse Odonata species. Odonata are among the sensitive freshwater insects widely used as ecological indicators and umbrella species, therefore these results about their assemblages in heavily modified and man-made habitats could contribute to future conservation activities of freshwater biota and habitats. Keywords: Dragonflies / environmental factors / aquatic and riparian vegetation / anthropogenic habitats / Lindenia tetraphylla
... Taking into account this temporal pattern, it is unlikely that the species produces two generations per year (Mahdjoub et al. 2015;Khelifa 2017;Khelifa et al. 2019). Taking into account the length of the emergence season, cattle pasturing and trampling, which cause habitat fragmentation, should be prevented (Lee Foote and Rice Hornung 2005). In addition, given that adults occupy a large terrestrial area during the flight season (Khelifa et al. 2016), it is important that the size of the buffer zone of the wetland should be large and maintained throughout the season (Semlitsch 1998). ...
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Urothemis edwardsii is one of the most threatened dragonfly species in the Mediterranean. Recent investigations and conservation efforts have increased the local geographic distribution of the species in Northeast Algeria, where a new population (named El Graeate) has been discovered. In the absence of information about the biology and behavior of U. edwardsii in this new site, a study was conducted on the emergence ecology of the species taking into account the temporal pattern of emergence, sex ratio, body size and microhabitat selection. Emergence, which was quite asynchro-nous, lasted for 50 days, with 50% of the population emerging within the first half of the period. Sex ratio at emergence was slightly female biased despite the absence of sexual size dimorphism, suggesting that size is not the only driving force behind mortality bias during the larval stage. There was a slight seasonal increase in the body size of exuviae (exoskeletons) in both sexes. Microhabitat selection, assessed as the vertical stratification of exuviae at ecdysis, was positively correlated with the height of supporting plants, but the relationship reached a plateau suggesting that there are predetermined limits to the vertical distribution of exuviae. These data will be essential for the future species protection, restoration and management attempts in the region.
... They are widespread and abundant under a range of environmental conditions (Clark and Samways 1996;Smith et al. 2007;Silva et al. 2010). To complete their lifecycle, odonates require a land/water interface and as a result can be ideal indicators of wetland habitats (e.g., Foote and Rice Hornung 2005;Kutcher and Bried 2014). Overall, odonates are sensitive indicators of disturbance and anthropogenic impacts in aquatic environments (Butler and deMaynadier 2008;Dolný et al. 2012;Kutcher and Bried 2014). ...
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Urbanization significantly alters hydrological regimes in cities by reducing infiltration rates and increasing runoff. Stormwater ponds have been constructed in North American cities to mitigate the effects of increased urban runoff by dampening floods and filtering out contaminants. However, these ponds may also provide habitat for wetland species in cities. This study aimed at determining the significance of stormwater ponds as attractive habitats for the adult stages of Odonata (dragonflies and damselflies), widely considered bioindicators of aquatic and wetland ecosystem health. A total of 41 urban stormwater ponds and ten rural natural ponds were sampled across the National Capital Region of Canada. On average, stormwater ponds had fewer species and lower abundance of dragonflies but, in contrast, more species of damselflies. Stormwater ponds had a higher total plant species richness because of a higher number of non-native species. However, some stormwater ponds had similar odonate and plant species assemblages to natural ponds. The variation in odonate abundance and species composition was largely explained by plant community composition and significantly linked to the presence of specific obligate wetland plant species. Overall, this study highlights the importance of wetland features in cities and points to design elements of stormwater ponds that could be implemented to enhance biodiversity and ecosystem services.
... Transformations of agricultural practices, including both intensification and abandonment, are one of the main causes of global biodiversity loss (Green et al., 2005;Norris, 2008;Tscharntke et al., 2012). Considering dragonflies, there is increasing evidence that this taxon is substantially impacted by intensive farming practices, which determine deterioration of the matrix in which their freshwater habitats are found (Lee Foote & Rice Hornung, 2005;Raebel et al., 2012;Koch et al., 2014). In the study sites, and generally, in the Alps, intensive agriculture impacted freshwater biodiversity by: (i) active abstraction of water for irrigation, which influences water levels and hydroperiod; (ii) the dramatic increase in the use of fertilisers (both natural and chemical), driven by the intensification of livestock farming in the last 50 years (Marini et al., 2011;Scotton et al., 2014), which determined the eutrophication of water bodies; (iii) the use of pesticides, which are washed and taken up to water bodies (Zedler & Kercher, 2005;Bartzen et al., 2010). ...
Article
• Freshwater environments are experiencing high rates of species extinction due to human impacts, with aquatic insects thought to be strongly threatened by these changes; however, long‐term research on this topic is scant. Among aquatic insects, dragonflies are considered valuable indicators of human disturbance at multiple scales. • This study addresses transformations of odonate communities of low elevation mountain wetlands in the Alps over the last century, comparing historical and present assemblages based on past records derived from scientific collections or literature and present data derived from site resurveys. • About 32.6% of species have been extirpated or strongly declined in the area (mostly temporary lentic and lotic water specialists, or cold‐adapted species). Conversely, only 12.2% of species were new or considerably increased (mostly permanent lentic specialists and warm‐adapted species). Nearly half of historical populations have been lost. The great majority of species which disappeared from all the study sites also disappeared (or strongly declined) at the regional scale. • Although gamma species richness was higher in the historical period compared with the present, mean alpha species richness does not significantly differ between the two, likely suggesting homogenisation of communities from historical to the present period. • Present communities of dragonflies show a significantly higher community temperature index compared with historical ones. • These patterns are putatively explained by the joint effects of land‐use change (drainage and reclamation), land‐use intensification or abandonment, environmental pollution, and anthropogenic‐driven climate warming.
... Jansen and Healey (2003) found that heavily grazed floodplain wetlands in Australia (with >0.6 cattle ha −1 ) had reduced frog diversity. Lowered vegetation height and complexity increase the exposure of ranids and bird nestlings to predators (Bloom, Howerter, Emery, & Armstrong, 2013;Burton, Gray, Schmutzer, & Miller, 2009), and limit perching sites for odonates (Foote & Hornung, 2005). Furthermore, dissolved nutrient concentrations and the incidence of eutrophication are increased in wetlands with high cattle densities (Pettit et al., 2012). ...
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• Semi‐natural marshland is becoming increasingly prevalent in Asia as a result of the continuing abandonment of rice cultivation. Although these marshes are important habitats for aquatic animals, they are susceptible to terrestrialization. Large mammalian herbivores that can retard terrestrialization are in decline globally, but domesticated bovids may serve as their surrogates, and could be used for managing semi‐natural marshes. Relevant research in Asia is lacking, however. • Aquatic macroinvertebrates were sampled in both the wet and dry seasons from 26 freshwater marshes (abandoned paddy fields) across Hong Kong, encompassing 15 sites grazed by feral bovids (yellow cattle and water buffalo) and 11 ungrazed sites. The aim was to investigate seasonal variation in the effects of bovids on macroinvertebrate communities in monsoonal marshes. • Four decades after paddy cultivation had been abandoned, semi‐natural marshes with low‐intensity bovid grazing (0.06–0.14 cattle ha⁻¹) had significantly higher (16%) site‐scale γ‐diversity. Macroinvertebrate communities at grazed sites had more Coleoptera and larval Odonata, and differed markedly from those at ungrazed sites. The effects of grazing on diversity and composition were unaffected by season, but season itself was a significant predictor of α‐ and β‐diversity and species composition. • This study is the first to record the responses of aquatic macroinvertebrate diversity and composition to large‐mammal grazing in Asian marshlands. Given that bovid grazing at low intensity can control plant growth, with concomitant benefits for wetland diversity, it is suggested that targeted grazing of short duration could be used for conservation management of abandoned paddy fields.
... Lentic sites were sampled to allow for quantification of species richness and relative abundance of odonates by implementing a standardized 1-km transect methodology (Pollard, 1977). This method allows for a wide range of lentic habitat types to be included, thereby eliminating species-specific activity and habitat bias (Foote & Hornung, 2005;Remsburg & Turner, 2009). A 1-km transect was established at each lake by selecting the shoreline with the greatest amount of sunlight, as this is the preferred odonate habitat (Corbet, 1999). ...
Article
The role of biotic interactions in shaping species distributions is a cornerstone of biogeographic theory; yet, it remains elusive. Such interactions are more likely to have an influence on organisms with obligate associations, such as hosts and their parasites. Whereas abiotic conditions may affect the abundance and distribution of parasites in ways similar to free‐living species, attributes of the host could also play a part. Here, we focus on parasitic water mites and their dragonfly and damselfly hosts, and use a hierarchical Bayesian model to examine the relative influence of the abiotic environment and biotic factors such as local host community structure and individual host characteristics on parasite intensity along a broad‐scale environmental gradient. Specifically, we assessed how climate, surrounding vegetation, water chemistry, host community structure as well the relative abundance and body mass of host species affected the intensity of parasitism on individual hosts along a latitudinal gradient. We found that water chemistry and body mass of the host were the best predictors of variation in parasite intensity among hosts. High parasite intensity was observed in hosts sampled from lakes with high pH, dissolved oxygen, and conductivity. Additionally, we found that the intensity of parasitism was strongly influenced by host species identity. In particular, body mass, which shows strong phylogenetic signal, was negatively related to parasite intensity. It may be that larger species, or individuals within species, are more immune to high level of parasitism and/or body mass is correlated with other traits of the host which relate to immunity. Considering both the abiotic environment and attributes of host species is necessary to understand why certain host individuals and locations exhibit more intense parasitism. Amid widespread decline of insect populations worldwide, some of which are attributed to pathogens and parasites, models predicting rates of parasitism in space and time could become an essential tool for guiding management and conservation efforts.
... Se ha sugerido que los odonatos muestran determinada correspondencia con la composición vegetal, ya sea terrestre o acuática (Cordero & al. 1999, Foote & Hornung 2005, Remsburg & Turner 2009). Debido a que la emergencia es la fase más vulnerable del ciclo de vida de los odonatos, la preferencia en el uso de las hojas como estructura de emergencia, constituye una estrategia conductual que permite reducir la influencia negativa de factores bióticos y abióticos. ...
Article
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The transference of biomass to terrestrial ecosystems is carried out in part by the adults of aquatic insects after their emergence from water, as it is in the case of odonates. The aim of this study is to characterize the emergence pattern of an odonate assemblage in an artificial lentic habitat of the National Botanical Garden of Cuba, from the harvest of exuviae. Fifty two samplings were carried out with a frequency of once a week, and an interval of seven to nine days, in four transect of 8 m². To characterize the emergence, the seasonal climate model was considered: rainy, poorly rainy and transition seasons. The change in climatic variables and habitat characteristics was registered, and was related to the emergence pattern. The variation in the use of resources during emergence was described. The emergence with a constant volume of water turned out to be asynchronous, with a predominance of accidental species and unequal abundance distribution. The rainy period was the season with the highest percentage of emergence, in which rainfall and relative humidity were the factors that most influenced the emergence pattern. The plants were the most used emergence substrate, and the decrease in vegetation cover corresponded to the alternative use of other substrates.
... In recent years, research in the field of ecological impacts has turned increasingly to the analysis of groups of indicator organismsbioindicatorsbecause of their specific, and known responses to changes in environmental conditions (Lee-Foote & Rice, 2005;Bevilacqua et al., 2009;Souza et al., 2018;Godoy et al., 2019;Molineri et al., 2020). The order Odonata (dragonflies and damselflies) is considered to be a model group in this sense, due primarily to the amphibious life cycle of these insects, which have aquatic larvae and terrestrial/flying adults, and the rapid response of this group to environmental changes in both aquatic (García-García et al., 2017;Mendes et al., 2019) and terrestrial systems (Dolný et al., 2012;Calvão et al., 2018). ...
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The insects of the order Odonata have been widely used as bioindicators of environmental quality in different types of ecological research. In general, the taxonomic level used is the species, but higher taxa, such as the family, have received less attention. Assuming that higher taxa can reproduce the impacts that occur at the species level, we use facets of diversity at the community to assess if Odonata families could be an efficient tool for the assessment of environmental impact in Amazon streams. We first assessed to what extent each family retains ecological information from the ecological diversity of the species of the suborder (Anisoptera or Zygoptera). We then quantified the degree of congruence between different taxonomic levels in the Odonata. Next, we evaluated the effects of environmental integrity on the facets of diversity of the families. Finally, we evaluated whether ecological thresholds can be detected using a family-level approach. We sampled adult odonates in 98 streams in the eastern Amazon, in the municipalities of Paragominas, Santarém, and Belterra, in the Brazilian state of Pará. The habitat integrity index (HII) was used to assess the environmental integrity of each stream. The congruence between the different taxonomic levels was evaluated using a Procrustes analysis. The degree of correlation of diversity facets was evaluated between families and each suborder. Linear mixed models and matrix regressions were used to measure the influence of environmental integrity on the diversity facets of the families. Higher-level ecological thresholds were detected using the TITAN analysis. The results of the analyses indicated a high degree of congruence between species-level and higher levels (family and suborder). The ability of the families to represent the diversity facets of the suborder is influenced by the abundance of individuals and the number of species in the family. The environmental integrity of the streams affects the facets of diversity of the families systematically, although cumulative measurements, such as abundance, appeared to be more advantageous as biomonitoring tools. The similarity of the responses observed at species and family levels supports the use of odonate families for the detection of ecological thresholds in stream environments. The sum of the evidence indicates that a family-level approach is effective for the identification of alterations in the environmental integrity of streams, providing valuable insights into the facets of diversity of the odonate community. The adoption of a family-level approach in environmental monitoring programs could optimize the investment of resources, in particular through the identification of specimens by non-specialists, permitting a significant increase in sampling effort and replication.
... Nevertheless, the occurrence of submerged and littoral vegetation might provide food, refuge and structure (e.g. for reproduction) for some macroinvertebrates (Fuentes-Rodríguez et al., 2013) and amphibians (Swartz and Miller, 2019). In our study, the lack of aquatic vegetation in the tanks could have prevented the proper establishment of odonate species (see Foote and Hornung, 2005;Hykel et al., 2020), as well as the occurrence of other aquatic species (e.g., aquatic beetle and bug species, see Deacon et al., 2018). Additionally, it is not known if tanks located at greater distances from the protected areas would also act as refuge habitats of macroinvertebrate assemblages. ...
Article
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The Azorean islands have been historically affected by human activities, mainly due to the combined effects of habitat degradation and fragmentation, and the introduction of exotic species. We here aim to analyze the role of environmental characteristics and spatial descriptors in supporting regional biodiversity of macroinvertebrates by considering natural ponds and artificial tanks. After the monthly variation of macroinvertebrate assemblages was assessed in three temporary and two permanent ponds in the Azorean island of Terceira during a complete inundation-desiccation annual cycle, the assemblage differences of 12 ponds (three temporary and nine permanent ponds) and 8 closely-located artificial tanks were analyzed across a range of landscape disturbances. Macroinvertebrate assemblages were found to differ according to hydroperiod and sampled months. Although the former explained the highest variance, macroinvertebrate differentiation by hydroperiod was also dependent on the study month. Our results also revealed a consistent monthly pattern of species replacement. However, the contribution of nestedness to the macroinvertebrate β-diversity was notable when temporary ponds were close to desiccation, probably indicating a deterministic loss of species due to the impoverished water conditions of the ponds facing desiccation. When the macroinvertebrate assemblages were analyzed in relation to physico-chemical variations and spatial descriptors, the artificial tanks were not clearly segregated from the natural ponds, and only differentiated by pH differences. In contrast, those natural ponds exhibiting high concentrations of total phosphorous (likely signs of anthropization) also discriminated the ordination of ponds in a distance-based redundancy analysis, and showed impoverished assemblages in comparison with well-preserved ponds. The macroinvertebrate assemblages of the natural ponds showed a significant spatial pattern, but this spatial influence was not significant when tanks and ponds were considered together. Our results suggest that tanks may act as possible reservoirs of biodiversity during the desiccation period of temporary ponds, but are unable to establish successful populations. These fishless permanent tanks can complement the conservation of a biodiversity that is largely maintained by the pristine high-altitude natural ponds. The establishment of a guideline for conservation management that also considers the artificial tanks is necessary to benefit the local and regional Azorean macroinvertebrate diversity.
... However, when the effects of transformation are severe, other variables related to anthropogenic disturbance may override the more natural drivers of heterogeneity in shaping dragonfly assemblages. For example, the severe negative influences cattle presence has on dragonfly diversity has been recorded in Canada (Hornung and Rice, 2003;Lee Foote and Rice Hornung, 2005), various parts of Europe (Rudolph, 1978;Declerck et al., 2006), and South Africa (Kinvig and Samways, 2000). Shading of habitats, including that caused by alien trees, negatively influenced dragonfly assemblages in Kenya (Clausnitzer, 2003), Brazil (Renner et al., 2016), and South Africa (Samways and Grant, 2006;Magoba and Samways, 2010). ...
Article
Landscape transformation and subsequent habitat loss locally extirpate populations and threaten ecosystem health. Timber plantations are a major threat to grassland ecosystems globally. An effective mitigation measure is the instigation of webs of large conservation corridors as ecological networks in plantation mosaics. These ecological networks incorporate natural water courses along with their matrices of natural grassland. Dragonflies are highly sensitive to habitat condition and are effective bioindicators of water quality. Here, we compare dragonfly diversity in conservation corridors, with nearby protected areas as controls, to determine the effectiveness of ecological networks for maintaining river ecosystem integrity, in the KwaZulu-Natal Midlands, South Africa. We also investigate the effect of ecological network corridor width on dragonfly assemblages. Lastly, we explore the importance of 18 environmental variables as drivers of dragonfly diversity. Dragonfly abundance, species richness, and Dragonfly Biotic Index scores (a scoring system based on dragonfly range of extent, threat status, and environmental sensitivity) did not differ between ecological network and protected area sites. Dragonfly abundance and species richness were positively correlated with ecological network corridor width. Landscape and water variables were the most important drivers of dragonfly assemblage composition in both ecological networks and protected areas. Management variables and those related to anthropogenic disturbance were not as important. This highlights the conservation success of these well-managed ecological networks for maintaining dragonfly biodiversity in forestry plantations, provided that corridors are wide enough. Implementation of ecological networks as a mitigation measure for plantation forestry is highly effective for lotic systems, and should be implemented more widely in environmental protection plans for transformed landscapes.
... concession (Coelho and Ribeiro 2006;Samways et al. 2010;Adu-Acheampong et al. 2016Kyerematen et al. 2018a). This is in line with other studies using very sensitive insect groups such as grasshoppers, ( Adu-Acheampong et al. 2016; Adu-Acheampong and Samways 2019a, 2019b), butterflies ( Bonfantti et al. 2009;Kyerematen et al. 2018aKyerematen et al. , 2018b), dragonflies (Lee Foote and Rice Hornung 2005;Acquah- Lamptey et al. 2013) and ants (Coelho and Ribeiro 2006;Majer et al. 2007) as surrogates to measure the impact of environmental stressors. Orthoptera and Hymenoptera are among the most important insect groups known for being environmentally sensitive and hence any change in their diversity or abundance can directly be linked to the health status of the environment in which they are located (McGeoch 1998;Samways et al. 2010) and additional reason that they are very conspicuous, easy to sample, and their biology has been well studied and can easily be related to conditions within the environment (McGeoch 1998;Samways et al. 2010). ...
Article
One of the most important bioindicators of change in habitat conditions, especially in tropical Africa, is change in insect diversity. In line with that, the dynamics of Orthoptera and Hymenoptera insect orders were studied and used as evidence of change in ecosystem health after a similar study on Lepidopteran groups revealed some level of degradation in the Tarkwa Gold Mine (TGM). Orthopteran and Hymenopteran species assemblages were sampled within the mine and characterised based on family diversity. Transect counts, sweep netting, malaise trapping and flight interception trapping methods were employed to sample abundance and diversity of insect assemblages of the above-mentioned insect orders. Results showed that few species belonging to these two orders were recorded within the mine, although the records were dominated by more aggressive and habitat degradation tolerant members as reported for the Lepidopteran group in a previous study. We conclude that records of diversity of these insect orders in this study shows a reduction in the ecosystem health within TGM. This finding is further proof that there is a general decline in biodiversity within the concession and hence care must be taken to encourage environmentally-friendly mining practices to avoid further degradation. Recommendations are made for environmental management to maintain more natural vegetation to serve as refugia for impacted animals within the concession.
... effects on Canadian prairie wetlands(Lee Foote & Rice Hornung, 2005), the assessment of habitat suitability(Harabiš & Dolný, 2012), and to determine environmental impacts in streams in the eastern Brazilian Amazon (deOliveira-Junior et al., 2015). Also, the comparison of adult and larvae responses is a valuable indicator of shallow lake restoration(D'Amico et al., 2004) and the examination of changes in both Odonata species diversity and number of individu- ...
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Genetic and morphological identification of dragonflies' larvae species in three high‐elevation Andean tropical lakes was done using DNA barcoding of the cytochrome oxidase 1 gene (COI). Phylogeny allowed inferring the evolutionary relationships of at least five species (from 74 samples) that belong to two different families within the Odonata order. Abstract in Spanish is available with online material. Resumen Los lagos Andinos son de gran importancia para comprender el pasado, presente y futuro de los estos ecosistemas de altura. Estos ecosistemas son únicos y se encuentran expuestos a una alta variación de temperatura y radiación solar cada día. Sin embargo, se conoce muy poco sobre la composición genética de los grupos taxonómicos que viven en estos lagos andinos de altura. El objetivo de este estudio fue la identificación de especies de libélulas en tres lagos andinos ubicados entre los 2000 a 3800 metros sobre el nivel del mar. Utilizando códigos de barras de ADN del gen de la subunidad 1 de la citocromo oxidasa (COI), analizamos y clasificamos 74 muestras recolectadas de los tres diferentes puntos de muestreo. El análisis filogenético permitió inferir las relaciones evolutivas para confirmar la presencia de al menos 5 especies que pertenecen a dos familias diferentes dentro del orden Odonata; Aeshnidae y Coenagrionidae, respectivamente. Basándonos en los registros disponibles de las bases de datos públicas GenBank y BOLD, llegamos a la conclusión de que existen al menos dos especies nuevas no descritas previamente, ya que nuestros resultados no coinciden con ningún registro previo. Este estudio intenta proporcionar evidencia para el uso de códigos de barras de ADN (por ejemplo, gen COI) con el fin de mejorar la precisión de los estudios de biomonitoreo. Más estudios son necesarios para proporcionar más información para la conservación de áreas ambientalmente amenazadas y la rehabilitación de zonas perturbadas antropogénicamente.
... grazing; Fig. 1.4b). Previous studies showed that odonate were very sensible to grazing during summer, with a strong impact on larval abundance and diversity (Foote et al. 2005). Here, cattle pressure on agricultural ponds may have been responsible for the non-significant link between vegetation structure observed in spring and odonate occurrence and abundance. ...
Thesis
Au cours des dernières décennies, le nombre de mares a connu un déclin de plus de 50 % dans les pays européens, atteignant parfois jusqu'à 90 % dans certaines régions. Cette diminution a entraîné une forte perte de connectivité entre les mares. Pourtant, ces écosystèmes petits et dispersés sont essentiels au cycle de vie d'une grande diversité d'espèces d'eau douce. Les politiques d'aménagement du territoire, comme la création des Trames Vertes et Bleues en France, visent à améliorer les continuités écologiques pour permettre le maintien des populations existantes et les échanges entre elles. Cependant, les études de connectivité entre les mares doivent prendre en compte les capacités de dispersion des espèces et cette information fait souvent défaut pour orienter les mesures de restauration. Dans le présent travail, nous avons étudié les capacités de dispersion des libellules à plusieurs échelles spatiales ainsi que les caractéristiques biologiques et les facteurs environnementaux qui façonnent leurs mouvements. Dans la première partie, nous avons évalué la colonisation par les libellules de 20 mares normandes pendant les trois années suivant leur création ou leur restauration. Les résultats mettent en évidence des taux de colonisation élevés pendant la première année et aucune différence de richesse spécifique n'a été constatée entre les mares nouvellement créées ou restaurées. Cela suggère que la restauration des mares après un assèchement total ne devrait pas toujours être prioritaire par rapport à la création de nouvelles mares dans les stratégies de gestion. Nous avons constaté que les espèces généralistes étaient davantage présentes la première année après la création ou la restauration des mares, alors que la présence d’espèces spécialistes des forêts augmentait avec l'âge du plan d’eau. Les résultats ont également mis en évidence que le contexte paysager autour des mares (i.e. milieu forestier ou ouvert) avait un effet sur la composition des communautés de libellules. Enfin, l'abondance totale des espèces d'odonates était liée à la densité des plans d’eau alentours. Ce résultat souligne que les mares très connectées peuvent abriter des populations plus importantes que les mares isolées et donc être plus résistantes aux perturbations. La deuxième partie fournit des éléments sur le développement larvaire d'Anax imperator et la relation entre les caractéristiques morphologiques des larves et des adultes. Les résultats suggèrent que la survie de cette espèce pendant la période de maturation pourrait dépendre de la longueur des individus. Nous avons également essayé d'étudier la dispersion natale en marquant 87 individus à l'émergence, mais seuls deux mâles ont été retrouvés après la période de maturation. Enfin, l'effet de deux polluants de l'eau (Round-up et DEET) sur le développement larvaire et les adultes d'Aeshna cyanea a également été étudié à différentes concentrations. Les larves ont été élevées dans des conditions de laboratoire et exposées à des concentrations allant jusqu'à 30 mg.L-1 des deux polluants. Aucun effet des polluants sur les conditions morphologiques des larves ou des ténéraux n'a été détecté, ce qui suggère que A. cyanea est une espèce tolérante aux potentielles pollutions de l'eau dans les mares. Le niveau de la protéine de stress HSP70 était également similaire selon les différents traitements, mais les adultes ténéraux présentaient des niveaux de stress plus élevés que les larves, ce qui suggère que l'émergence a provoqué un stress élevé chez les individus.
... Odonata survey goals and objectives can take many forms, ranging from those that are complex and challenging to attain (e.g., obtaining comprehensive checklists of species for large and complex suites of habitats) to those that are comparatively simple (e.g., determining presence/ absence of selected species at spatially restricted or ecologically simple sites). In addition to obtaining a checklist or representative assessment of species at a site, surveys can also be designed to assess habitat quality (Carle 1979, Foote and Hornung 2005, Oertli 2008). BENJI PIERSON In any survey, the investigators must determine the level of thoroughness and accuracy they are willing to accept. ...
Article
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Various logistical questions must be addressed when surveying or monitoring dragonflies and damselflies (Odonata) in Wisconsin. These include: 1) when, how often, and for how long the sampling should be done, 2) what sampling gears and how many observers should be used, 3) what habitats should be sampled, and 4) on what life stages a survey should focus. In this report I review and synthesize the relevant literature on Odonata sampling protocols to provide guidance for Odonata surveys in Wisconsin. Any survey design should be driven by the goals for the effort including the levels of accuracy and thoroughness the investigators are willing to accept; no single survey design will meet all possible goals. Obstacles to survey goals include complications with species identification, difficulties in detecting rare species, influences of season, weather, time of day, and habitat, limitations of sampling gear, issues related to sampling frequency and duration, and the peculiarities of various species. Surveys should primarily target adults, usually males, but nymphs and exuviae should be sought for some taxa, particularly if confirmation of reproduction at a site is needed. All aquatic habitats should be targeted in property surveys. The most effective way to increase the detection of rare species is to increase effort. Recommendations for survey timing and sampling frequency are provided.
... grazing; Fig. S2b). Previous studies showed that odonates can be very sensible to grazing during summer, with a strong impact on larval abundance and diversity (Foote et al. 2005). Here, cattle pressure on agricultural ponds may have been responsible for the non-significant link between vegetation structure observed in spring and odonate occurrence and abundance. ...
Article
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Ponds are lentic waterbodies with a high conservation value for biodiversity that have long been overlooked by management policies. Recent initiatives aimed to promote the conservation of these ecosystems by restoring or creating new ponds throughout Europe. Therefore, studying responses of aquatic invertebrates to local pond characteristics and connectivity between them is determinant to understand community dynamics and colonization processes of these scattered ecosystems. We studied larval communities of odonates in 20 created or restored ponds to assess their colonization during the first 2 or 3 years. Community dynamics in relation to pond vegetation, landscape context and connectivity with other ponds were also investigated. No difference in species richness was found between restored and created ponds. Most species colonized the ponds during the first year, but a different pattern in colonization was observed between Anisoptera and Zygoptera. Community composition was related to the landscape context of ponds and the time since pond creation or restoration. Abundances were positively related to pond connectivity, especially in the suborder Zygoptera. No relationship was found between vegetation and Anisopteran larvae, while Zygoptera seem more sensible to the vegetation structure due to their endophytic oviposition. This work confirms the high colonization capacity of odonates and shows that creation of new ponds could be as efficient as pond restoration to enhance the conservation of freshwater species. It also highlights that landscape characteristics and connectivity between ponds are determinant to support higher abundances and a posteriori increase population viability at the landscape scale.
... They either live attached to the macrophytes or bottom substrates and play a significant role in the food web's predator and prey population. They serve as biological indicators since these communities are sensitive to changes in the environment (Watson et al., 1982;Clark and Samways, 1996;Samways and Steytler, 1996;Foote and Rice Hornung, 2005;Stewart and Samways, 2008;Al-Shami et al., 2014;Buss et al., 2015;Gebrehiwot et al., 2017). They also function as biological controlling agents, and the effectiveness of larvae and adults of Odonata, Bradinopyga germinata (Anisoptera: Libellulidae) against the dengue vectors was identified by Tyagi (2013, 2015). ...
Research
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The Journal publishes invited review articles, special issues and original contributions dealing with all aspects of Aquatic Biology and Fisheries, and appreciates multidisciplinary research papers on emerging and frontier areas of research in Aquatic Biology and Fisheries. The contributions can be in the form of original research papers and short communications relevant to freshwater, brackishwater and marine environments.
... They either live attached to the macrophytes or bottom substrates and play a significant role in the food web's predator and prey population. They serve as biological indicators since these communities are sensitive to changes in the environment (Watson et al., 1982;Clark and Samways, 1996;Samways and Steytler, 1996;Foote and Rice Hornung, 2005;Stewart and Samways, 2008;Al-Shami et al., 2014;Buss et al., 2015;Gebrehiwot et al., 2017). They also function as biological controlling agents, and the effectiveness of larvae and adults of Odonata, Bradinopyga germinata (Anisoptera: Libellulidae) against the dengue vectors was identified by Tyagi (2013, 2015). ...
Article
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The spatial variation of benthic odonate community assemblage in various zones (upper, middle, and lower zones) of the urban river Killiyar was assessed using the tools of geographic information system (GIS) and investigated their interaction with select water quality parameters. Benthic odonate larvae collected during this study belong to predators–engulfers of the functional feeding groups. A total of 147 individuals of 12 genera across nine families of benthic odonate taxa were recorded in this study. Out of the total taxa observed, Gomphidae comprised 34% individuals, followed by Libellulidae (33%). The former taxa were the dominant family in all the zones except the lower zone. The spatial analysis demonstrated high diversity and richness in the stations of the middle zone while moderate diversity in the rest of the stations. The population density observed was high at station Idappazhanjhi (K10). The distribution of taxa was relatively higher in the middle zone than that of other zones. The taxa Libellulidae was observed in most stations and directly associated with water temperature, pH, and dissolved oxygen. The major drivers that govern benthic odonate community assemblages in Killiyar were pH and dissolved oxygen. Investigating the community assemblage using GIS tools is novel and provides a better understanding of the ecology of odonate larval communities and their association with water quality. The outcome of this study supports the formulation of management strategies to protect the odonate diversity and conservation of their habitats, the riverine ecosystems in the urban landscapes in particular.
... This may be impactful for species whose distribution is largely limited by abiotic characteristics of freshwater habitats whose data are not available in certain parts of the world. Factors that are known to influence odonate distributions include sunlight availability [36,37], water turbidity [38,39], substrate type [40], vegetation [41], and the water pH [42,43]. In regard to Vanuatubasis, prior observations seemed to show that streams where the genus was collected had large mineral deposits, likely a result of high amounts of calcium carbonate, which can lead to basic pH levels [44]. ...
Article
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Vanuatubasis Ober and Staniczek is a genus of damselfly endemic to Vanuatu. Little is known about the distribution and general natural history of the genus. We present the results of 14 weeks of fieldwork in Vanuatu to provide a better understanding of the biology of this genus. Specifically, we tested ecological niche models to predict the presence of Vanuatubasis throughout the region and explored how water pH may play a role in their distribution and ecology. The results of this fieldwork refined our model and further predicted the presence of this genus on additional islands. We also found stream pH as a strong predictor for the presence of Vanuatubasis, with their presence in alkaline streams significantly higher (p < 0.001). The mean pH for those streams where the genus was collected was 8.44 (n = 53).
... Sampling of adult dragonflies and damselflies took place in March 2012, September 2012, and January 2013 to cover both seasons: dry (March 2012 and January 2013) and rainy (September 2012). We captured mature adults in tandem (males and females), or mature male adults that exhibited territorial behavior, to facilitate taxonomic identification and avoid counting nonresident adults (Foote and Rice Hornung 2005;Chovanec et al. 2015;Patten et al. 2019). We know that the more accurate way to estimate species abundance is by counting only breeding adults that can reproduce in the sampling site. ...
Article
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Human activities have impacted many environments on earth, and thus several species are facing an increased risk of extinction. The environmental crisis requires rapid tools to assess the ecosystem health accurately. Studies have been conducted with visual indices that quantify habitat integrity by predicting species richness and diversity. However, whether a diverse clade can predict habitat integrity has not been used. The genus Argia (Rambur, 1842) is one of the most locally diverse groups in southeastern Mexico. In this context, we hypothesized that the occurrence, species richness, and diversity of adults Argia spp. could be a better predictor of the Visual-Based Habitat Assessment Score (VBHAS) than the other taxonomic levels or less diverse clades. We found that the richness and diversity of Argia spp. are positively correlated with VBHA scores, as same as taxonomic ratios. Simultaneously, VBHA scores increase to 23.51 times when Argia spp. diversity increases. We discuss the possible use of a diverse Odonata clade, as Argia spp. could surrogate habitat integrity for local long-term biomonitoring programs. This approach requires testing with other indices and verifying a reliable and consistent relationship between diverse clades and environmental assessment scores.
... Vegetation structure benefits Odonata through resource availability and shelter (Buchwald, 1992), with positive relationships between Odonata and plant species richness observed at multiple spatial scales (Honkanen et al., 2011). Moreover, the height of key plant species also determines Odonate diversity, emphasizing the importance of vegetation structure for fliers and perchers (Lee Foote and Rice Hornung, 2005). The use of agrochemicals (e.g., high rate of fertilizer application) to sustain crop productivity is one of the leading causes of water quality impairment in oil palm waterways (Khatun et al., 2017). ...
Article
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Large-scale oil palm agriculture has caused deforestation in the tropics, but also degrades stream water quality and reduces aquatic biodiversity. Though the outcomes of industrial-scale oil palm plantations for biodiversity have been explored extensively, the consequences of small-scale oil palm agriculture for freshwater macroinvertebrate fauna are poorly understood. Here, we explored the impacts of small-scale oil palm agriculture on aerial adult Odonata (the dragonflies and damselflies), which, due to their inherent sensitivity to habitat degradation, represent useful indicators of wider ecosystem health. We surveyed riparian corridors of man-made waterways in natural habitats converted into agricultural lands in both peat swamp and mangrove forest, comprising a total of 60 sampling units across a region of Peninsular Malaysia where such small-scale agricultural practices are widespread. We hypothesized that physicochemical water quality of oil palm waterways together with riparian vegetation influence Odonata species richness and composition. Our results revealed that Odonata species richness increased with dissolved oxygen, water temperature and vegetation cover, but decreased with water level, pH, and total dissolved solids. Species composition was influenced by both dissolved oxygen and pH. The present study provides valuable insights into the effects of small-scale oil palm agriculture for water quality of associated aquatic habitats, and subsequent responses of adult Odonata. Therefore, smallholders should reduce the use of chemical pesticides and fertilizers to improve the conservation value of oil palm waterways for both Odonata and aquatic fauna more generally, in order to be certified as biodiversity-friendly agriculture.
... However, studies comparing the communities of highway ponds and surrounding non-highway ponds are rare and comprise amphibians (Le Viol et al., 2012) and aquatic macroinvertebrates (Le Viol et al., 2009;Meland et al., 2020). Adult Odonata have been neglected, although these amphibiotic insects are versatile and widely used indicators of freshwater and the terrestrial health (e.g., Foote and Hornung, 2005;Oertli, 2008). They highlight environmental changes, with different species responding differently to particular changes (Samways and Sharratt, 2010); this feature is exploited in commonly used indices such as the dragonfly biotic index (DBI; Samways and Simaika, 2016;Simaika and Samways, 2011). ...
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Stormwater management ponds, which are constructed to retain excess runoff and pollutants from traffic, play an important role in the freshwater biodiversity in highly modified areas. However, their roles in agricultural and semi-natural landscapes remain largely unexplored. In this study, we used Odonata as a bioindicator to compare a set of highway stormwater ponds and surrounding ponds within an agricultural and semi-natural landscape to examine the extent to which stormwater ponds act as biodiversity refuges. We analyzed the differences in environmental parameters and the richness, compositions, and conservation values of the odonate communities of stormwater and surrounding ponds. We also examined the factors controlling the differences in the communities of both pond types. The stormwater ponds were smaller, less eutrophicated, less shaded by trees, less stocked with fish, and less connected with other waterbodies than the surrounding ponds. However, they had a higher plant diversity and pH values and were more densely overgrown with vegetation. Compared with surrounding ponds, stormwater ponds had a higher Odonata richness and β-diversity, but their taxonomic distinctness was significantly lower. Therefore, stormwater ponds hosted more variable communities but their assemblages were taxonomically similar. Indicator species were only identified in stormwater ponds. Furthermore, stormwater ponds harbored more species with higher conservation values. The most important factors affecting the differences between stormwater and surrounding ponds were the trophic state, relative tree shading, and fish stocking intensity. With their increase, the richness and rarity decreased. Our results highlight the potential of stormwater ponds to enhance the biodiversity outside urban areas by providing specific habitat conditions that are unique to the surrounding agricultural landscape. In addition, we suggest management practices that can be used to enhance their biodiversity conservation function.
... Libellen eignen sich aufgrund ihrer semiaquatischen Lebensweise und ihrer engen Bindung an bestimmte Umweltbedingungen hervorragend als Indikatoren für die Untersuchung von Umwelteinflüssen auf die Biodiversität von Gewässerökosystemen (Foote & Hornung 2005, Samways 2008). Libellen reagieren sensibel auf Veränderungen abiotischer und biotischer Umweltfaktoren (Corbet 2004, Crumrine et al. 2008, Oertli 2008. ...
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Owing to the drastic loss of natural freshwater habitats over recent decades, anthropogenic waterbodies are taking on an increased significance for the conservation of biodiversity. The value of traditionally managed carp-pond complexes for biodiversity is well known. Nevertheless, the periodic draining of ponds for harvesting and high fish-stocking intensities are assumed to have negative effects on biodiversity. However, empirical studies of the impact of carp farming on pond biodiversity are still scarce. In this study, we analyzed the effects of habitat quality and pond management on odonate communities in an extensively managed carp-pond complex in Upper Lusatia (Saxony, Germany). The study stites included farmed carp ponds characterized by various habitat structures and stocking bintensities as well as abandoned carp ponds and new ponds created for species conservation. The carp-pond complex hosted a very high diversity of dragonflies, which can mainly be attributed to the small-scale coexistence of different management regimes and habitat structures. The most important factors for a high species diversity of odonates were a high structural diversity and a short duration of the drained period. The different pond types harbored distinct odonate assemblages. Owing to the sensitivity of several odonate species to drought, the existence of perennial conservation ponds had a substantial significance for preserving species richness in the study area. Nevertheless, even the ponds with the longest drainage phases hosted odonate species of high conservation concern. The results of this study underline that traditional carp farming can promote odonate diversity in Central European anthropogenic landscapes. Based on our results, we outline recommendations for pond management to maintain the biodiversity of carp ponds.
... Long-term monitoring is vital for bioindicator identification and their use as surrogates in monitoring diversity and assessing perturbation effects on insect populations (Conrad et al., 2007;McGeoch, 2007;Samways, McGeoch, & New, 2010; but see Likens & Lindenmayer, 2018 for potential pitfalls of indicator species use in monitoring programmes). The Odonata are excellent indicators of the health of freshwater and its terrestrial surroundings (Foote & Hornung, 2005;Dijkstra, 2007;Butler & deMaynadier, 2008). However, continuous, long-term studies of these charismatic insects are scarce, as reported by Moore (1991). ...
Article
• Most ecological studies involving insects are based on medium‐ and short‐term observations; however, the extent to which such data captures reality remains unclear. • We investigated the long‐term dynamics of two Odonata communities (disturbed and undisturbed sites) over 18 years and analysed the differences in the short‐ and long‐term results. We also focused on the sampling methodology to enhance the efficacy and objectivity of long‐term monitoring involving Odonata. • During one year, we captured only 53% of the overall species richness; during three consecutive sampling years, it was 65%. To capture 95%, we needed 16 years. Changes in quantitative similarity (Renkonen index, P) were more pronounced within sites over time than between sites. Species constancy significantly increased with the maximum abundance class but decreased with increasing fluctuation ratio and specialisation (Dragonfly Biotic Index). Based on exuviae, we detected half of the species compared to adults, but the species accumulation curves peaked after a few sampling years. • Long‐ and short‐term monitoring yield different results, both qualitatively (species richness, specialisation) and quantitatively (abundance, dominance). Ideal sampling should be sequential, lasting at least 10 years (capturing >80% of species). Intermittent sampling (one‐year interspersed with pauses), allowing the inclusion of multiple sites in monitoring programme, may also provide satisfactory results when performed over a longer period. • Over the long term, sampling adults semi‐quantitatively and exuviae qualitatively provided sufficient information, while being feasible in terms of both personnel and costs, thereby overcoming the main pitfalls of long‐term monitoring programmes.
... In the present study, we present and assess the quality of the database of water beetles from Morocco (Bennas 2002;Benamar 2015;Bennas et al. 2016;Benamar et al. 2021aBenamar et al. , b, c, 2022aGuellaf et al. 2021). Water beetles have been used as tools for conservation purposes, mainly identifying priority areas for freshwater biodiversity conservation in Europe, USA, South America, Australia, and Morocco (Abellán et al. 2005Bennas et al. 2009;Sánchez-Fernandez et al. 2006, 2013Zamora-Marin et al. 2016), as they have been recognised as suitable surrogates of freshwater biodiversity (Lee Foote and Rice Hornung 2005;Sánchez-Fernández et al. 2006;Slimani et al. 2019). ...
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Conservation-planning approaches must be supported by a good understanding of the geographical distribution of species. Despite the efforts conducted so far to compile data on aquatic insects, the information on the distribution of water beetles in Morocco is scarce. In this study, we assess for the first time the degree of inventory quality of aquatic insects in Africa. Using an exhaustive database of Moroccan water beetles, likely the most complete database for any group of aquatic insects in Africa (with 11,229 records for 305 species), we specifically aim to explore the patterns of species richness, sampling effort and inventory completeness at four different spatial resolutions, identifying those spatial units that can be considered as sufficiently surveyed, and locating areas in need of further sampling effort. Our results showed a lack of complete and extensive inventory data; as less than 12% of Moroccan cells at the coarsest resolution assessed (45′) can be considered as well surveyed (slope < 0.1 and survey completeness > 70%), while at the finest resolution (7′), only 1% of Moroccan cells could be identified as being well prospected. Finally, we highlight the importance of these procedures to improve monitoring planning of aquatic fauna and to improve their effective conservation and management. Implications for insect conservation Considerable information is still required to provide an accurate picture of the richness patterns of aquatic insects in North-Western Africa. Thus, results on the pattern of species richness must be used cautiously, as they could be just mirroring the pattern of sampling effort carried out. We recommend the use of modelling procedures as a shortcut to improve our knowledge on the biodiversity patterns of aquatic insects in North-Western Africa and to establish efficient conservation strategies for their protection.
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Assessment of surface waters based on odonatological investigations (Odonata)-methods for standing and running waters with an exemplary application at the river Mattig (Upper Austria).-In recent decades, the importance of odonatological studies in water management has greatly increased, since Odonata are good indicators of morphological and hydrological conditions of water bodies. The application of this guideline is intended to ensure the standardisation of dragonfly-based studies and thus the comparability of results. The aim of the field survey method described is to obtain as complete a picture as possible of the species spectrum reproducing at a given site by monitoring and recording adult dragonflies. Sightings of tenerals, additional recording of exuviae, estimates of the number of individuals as well as observations of reproductive behaviour serve to determine whether or not species are autochthonous to the site. According to the legal requirements of the EU Water Framework Directive and the Austrian Water Law (Wasser-rechtsgesetz, WRG), the assessment is based on a comparison of the water-type-specific dragonfly fauna with the status quo. In accordance with WRG, various methodological approaches have been developed for standing and running waters, to which reference is made in this paper. As an example, the restructuring measures at the hyporhithron stretch of the river Mattig (Upper Austria) near its mouth into the river Inn have been evaluated by means of a study on dragonflies carried out in 2019. The longitudinal classification of the Odonata represents the methodological basis for determining the Odonata reference species and any deviations. K e y w o r d s :
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Background: The Odonata, dragonflies and damselflies, constitute one of the more charismatic and better-studied orders of insects. The approximately 6,000 extant species on Earth can be variously found on all continents, except Antarctica. A relatively stable taxonomy, a relative ease of species identification and an aquatic immature stage has made the Odonata a taxon of interest in documenting the symptoms of global environmental change, especially at higher latitudes. The Odonata fauna of the north-temperate Canadian province of Quebec includes 150 species, many of which are at the northern limits of their geographic distribution. New information: Quebec hosts multiple entomological specimen depositories, including seven publicly-accessible research collections. One of these, the University of Montreal's Ouellet-Robert Entomological Collection, houses an exceptionally large collection of Odonata. An initial specimen data capture project for this collection gathered 31,595 Quebec Odonata occurrence records, but several Quebec species were missing and geographic coverage was biased towards the Montreal region. To complement this dataset, we undertook to digitise the Odonata records of six other public research collections. They are, in order of Quebec Odonata collection size, the Laval University Entomological Collection, McGill University's Lyman Entomological Museum, the Insectarium of Montreal Research Collection, the Quebec Government's Insect Collection, Bishop's University's Insect Collection and the Laurentian Forestry Centre's René-Martineau Insectarium. Of the 40,447 total specimen occurrence records, 36,951 are identified to the species level, including 137 of the 150 species officially-recorded in Quebec and 2 non-nominotypical subspecies. We here summarise the data and highlight the strengths and weaknesses of the datasets. The complete dataset is available with this publication (Suppl. material 1), whereas the specimen data associated with each collection are available as Darwin Core archives at Canadensys.net and will be updated as appropriate.
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Salinity is a limiting factor for many invertebrates, especially for Odonata which are typically associated with freshwater ecosystems. In Europe, 15 Odonata species inhabit brackish wetlands and only few detailed data on their tolerance toward salinity are available. We investigated Odonata fauna in 11 sampling stations situated in three estuarine areas (northern Adriatic coastline) which differed in salinity conditions (freshwater- polyhaline habitats) in order to assess affinity of Odonata species to brackish habitats and to describe their distribution pattern in coastal wetlands. Adults, exuviae (the remains of the exoskeleton after the last larval instar), and the main chemical and physical water parameters were sampled every two weeks for one year in each station. In total, 25 species were detected and 56% of them were able to complete their life cycle in brackish water environments. Our results showed that freshwater and oligohaline ponds were the most favorable for dragonflies, with an overall higher species richness. There was a high species turnover along the salinity gradient, with a strong differentiation among the communities along the gradient. Considering the exuviae, we observed a high specificity with respect to the habitat conditions (7 species exclusive of freshwater sites and 6 of oligohaline ones, respectively). Among the adults, 4 species were found exclusively in freshwater habitats and no species seemed to be strictly connected with oligohaline habitats. Coastal wetlands, composed by a mosaic of different habitats, especially when freshwater and seawater are close together, support many Odonata species with different tolerance towards salinity conditions. They also provide useful insights for conservation and management actions.
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The relative role of biological and abiotic filters in the assembly of co‐occurring taxa is of broad interest to ecologists. While some authors point to biological interactions (e.g., competition) as the stronger driver of ecological selection, others assert that abiotic conditions are more important because they filter species at the regional level. Because communities influenced by a dominant abiotic filter (e.g., Prairie Pothole Region [PPR] wetlands, each varying in their ponded water permanence) often have strong cross‐taxon relationships, we can study these communities to better understand the relative influence of abiotic versus biotic filters on community structure. Using functional dispersion as our measure of communities, we test six alternate hypotheses about the relative importance of various pathways representing influence of biological and permanence filters on birds, aquatic macroinvertebrates, and wetland plants in the northwest PPR using structural equation modeling. We aimed to understand whether (1) ponded water permanence alone explained functional dispersion; (2) the influence of permanence on functional dispersion was direct or mediated; and (3) abiotic filtering by permanence was stronger than biotic filtering by co‐occurring taxa. The best model suggests that there is a direct influence of permanence on the functional dispersion of each taxonomic group and that both bird and macroinvertebrate functional dispersion are causally related to plant functional dispersion, though for invertebrates, the influence of plants is much less than that of permanence. Thus, the relative importance of wetland permanence and the functional dispersion of co‐occurring taxa depend on which taxon is considered in PPR wetlands.
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Odonata is considered a "flagship" group of insects and its investigation is of primary importance especially for protected areas where freshwater ecosystems occur. In this study, we focused on Odonate fauna in the "Cansiglio Forest" (Veneto, Italy), a karst area where the only checklist available dates back more than 40 years ago. In order to update the Odonate adult distribution in the area, we selected 21 ponds that were sampled monthly, from May to August, during a 2-years survey. In total, 21 species (belonging to 14 genera and 5 families) have been recorded: we confirmed 15 species from the previous species list and we added to the whole species list 6 new species. Dominant families were represented by Libellulidae (33%) and Aeshnidae (23%), the most common genus was Sympetrum (19%), and the most frequent species was Coenagrion puella (63%). In term of patterns of species richness, highly grazed and pastured ponds exhibited the lower number of species and individuals, as a probable response to the high level of animal disturbance on the vegetation and due to the eutrophication processes. Our results are important also in terms of conservation and management of freshwater sites belonging to Natura 2000 site.
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1. Wetlands are ecologically and economically important ecosystems but are threatened globally by many forms of human disturbance. Understanding the responses of wetland species to human disturbance is essential for effective wetland management and conservation. 2. We undertook a study to determine (i) whether anurans can be used effectively to assess the ecological integrity of wetlands affected by groundwater withdrawal and, if so, (ii) what effect increasing urbanization might have on the utility of anurans as wetland indicators. We monitored the intensity of anuran calls at 42 wetlands in south-western Florida throughout 2001-2002 and 2005-2009. 3. We first validated the use of anurans to assess wetland integrity using a small group of wetlands by comparing anuran calling and subsequent tadpole development with an established index employing vegetation composition and structure. We then verified that the results could be expanded to a variety of sites throughout the region. Finally, we focused on urbanized wetlands to determine whether urbanization could interfere with the use of anurans to assess wetland integrity. 4. We used PRESENCE to estimate occupancy and detection probabilities and to examine the relationship between occupancy and five covariates expected to influence individual species occurrence. We used FRAGSTATS to calculate the mean proximity index for urbanized wetlands, which assesses the size and distribution of land use types within a specified area. 5. Our results showed that the group of species including oak toad Anaxyrus quercicus, southern cricket frog Acris gryllus, pinewoods treefrog Hyla femoralis, barking treefrog Hyla gratiosa, and little grass frog Pseudacris ocularis is a reliable indicator of wetland integrity. However, this same group of species, which is sensitive to wetland health, is selectively excluded from urbanized wetlands. 6. Synthesis and applications. Although anurans are effective indicators of wetland health and complement vegetation surveys, the usefulness of this group for monitoring the ecological integrity of wetlands can be substantially reduced, or eliminated, as a consequence of urbanization. We urge for careful consideration of confounding factors in any studies examining the utility of indicator species.
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The community structure of lotic odonates (Insecta: Odonata) changes downstream, but it is difficult to untangle natural and anthropogenic causes. We surveyed larvae and adults at 15 sites along the Reedy River in Greenville Co., SC, USA, from sites in forested suburban landscapes through the urban core of the city of Greenville. We used principal component analyses and Akaike information criteria models to describe the relationships between larval and adult community descriptors (abundance, richness, and diversity) and habitat characteristics at several spatial scales, including water chemistry, sediment and detritus, aquatic and streamside vegetation, and the percent cover of landforms in the surrounding landscape. At all scales, larval abundance, richness, and diversity correlated with the amount of detritus. At a small scale, adult indices correlated with the amount of sunlight and streamside vegetation. Zygopteran community composition was nested at a large scale; richness and diversity did not correlate with changes in the landscape but increased downstream. Anisopteran composition was also nested, but richness correlated with the percent cover of field, wetland, and open water in the habitat and was unrelated to downstream site position. Landscape transformation affected anisopterans more than zygopterans by opening habitats that facilitate these generalist heliotherms.
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Human activities have impacted many different habitat types on Earth, and there is a requirement for tools with which to accurately assess the level of damage incurred by ecosystems. For environmental analyses and monitoring, rapid stream assessment techniques emphasize geomorphological characteristics, biological potential, and habitat integrity characteristics. Using the principles and concepts of aquatic biology and ecology, we determined whether the visual-based habitat evaluation score is related to Odonata species diversity at different taxonomic levels. We hypothesized that habitat assessment is correlated positively with the local diversity of one Odonata taxonomic group. We found that the abundance, species richness, and diversity of Argia , one of the most locally diverse genera in southeastern Mexico, are positively correlated with habitat integrity scores. High richness (of up to eight species per site) corresponds to high integrity scores. Simultaneously, habitat integrity scores increase 23.51 times when Argia diversity (surface area) increases. We discuss the possible advantages of using a diverse Odonata clade ( Argia ) as a surrogate for local habitat assessments. Long-term biomonitoring programs could be applied using this novel approach in this specific Neotropical area. This study is framed within the focus of biodiversity and ecosystem functioning (BEF), however, it must be tested with other indices and a reliable and consistent relationship must be verified between diverse clades and environmental assessment scores.
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Con el fin de evaluar la diversidad del orden Odonata y relacionarla con la calidad del ambiente, en San Cristóbal de Las Casas (Chiapas) se eligieron cuatro humedales de acuerdo con su accesibilidad y permisibilidad. Para la tipología ambiental se consideró, entre otras características, la calidad visual, estimada a través del Índice del Estado de Conservación de Humedales (IECH). Recolectas sistemáticas mensuales de los odonatos adultos fueron realizadas entre julio de 2014 y junio de 2015. Un total de 14 especies, distribuidas en cinco familias y 10 géneros fueron encontradas. El género Argia fue el de mayor riqueza, mientras que Ischnura denticollis y Enallagma rua representaron las especies dominantes. Las Cañadas, humedal con calidad visual subóptima, presentó la mayor diversidad de libélulas al integrar un ambiente lótico. El grado de alteración de la vegetación acuática, como uno de los parámetros evaluados en la calidad visual, fue muy importante en las diferencias encontradas en la diversidad y abundancia de Odonata en los cuatro humedales. María Eugenia y La Kisst catalogados como ambientes con calidad visual óptima y regular, respectivamente, obtuvieron la mayor similitud en su odonatofauna relacionada con las distintas formas de vida de su vegetación acuática y por el tamaño equivalente de estos dos humedales.
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A major challenge in ecology is understanding what enables certain species to persist, while others decline, in response to environmental change. Trait-based comparative analyses are useful in this regard as they can help identify the key drivers of decline, and highlight traits that promote resistance to change. Despite their popularity trait-based comparative analyses tend to focus on explaining variation in range shift and extinction risk, seldom being applied to actual measures of species decline. Furthermore they have tended to be taxonomically restricted to birds, mammals, plants and butterflies. Here we utilise a novel approach to estimate trends for the Odonata in Britain and Ireland, and examine trait correlates of these trends using a recently available trait dataset. We found the dragonfly fauna in Britain and Ireland has undergone considerable change between 1980 and 2012, with 33 and 39% of species showing significant declines and increases respectively. Distribution type was the key trait associated with these trends, where southern species showed significantly higher trends than widespread and northern species. We believe this reflects the impact of climate change as the increased ambient temperature in Britain and Ireland better suits species that are adapted to warmer conditions. We conclude that northern species are particularly vulnerable to climate change due to the combined pressures of a decline in climate suitability, and competition from species that were previously limited by lower thermal tolerance.
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O presente trabalho objetivou-se a: avaliar a importância das áreas de Veredas na predição de ocorrência das espécies de Odonata; avaliar se a riqueza de Odonata se relaciona com a distribuição de áreas de Vereda no país; conhecer a odonatofauna associada a uma Vereda no município de Uberlândia, MG; construir um checklist com dados biológicos de habitat e de distribuição.
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The relatively rare freshwater ecosystems in the arid southwestern United States serve as biodiversity hotspots, yet they remain among the most threatened systems in the world due to human impacts and climate change. Globally, arid region wetlands remain understudied with respect to their ecology, making assessments of quality or restoration efforts challenging. To address these needs, this project aims to better understand the factors that drive water quality and macroinvertebrate community composition of wetlands of the US desert Southwest. Water quality and macroinvertebrate data were collected over three years from 14 different wetland and riparian sites spanning across West Texas, New Mexico and Arizona. Principal Component Analysis (PCA) indicated that salinity related variables such as chloride, sulfate and conductivity were the greatest drivers of environmental variance (32%) among sampled desert wetlands. Nutrients such as nitrate and phosphate described a second axis, with 22% of variation in environmental data explained, where we found a clear distinction between wastewater and non-wastewater wetlands. Nutrients were shown to have the greatest impact on macroinvertebrate communities with wetlands receiving wastewater showing more uneven distribution of functional feeding groups and lower Simpson Index scores. These sites were dominated by filter feeders and had lower relative abundances of predator and collector-gatherer taxa. There was also a significant decrease in metrics related to diversity and environmental sensitivity such as % Ephemeroptera-Odonata-Tricoptera (EOT) within high nutrient sites. Increased salinity levels were also shown to correlate with lower Simpson Index scores indicating that increased salinity resulted in a decline in macroinvertebrate diversity and evenness. To enhance the water quality and diversity in their sites, we suggest that managers of these valuable created habitats that are fed with wastewater might try to find less nutrient-rich water sources, or dilute effluent with another water source such as groundwater. Overall, the nutrients within effluent water have shown to significantly alter community composition especially in desert wetlands where macroinvertebrates may be more adapted to salinity. Though macroinvertebrate communities in wastewater sites may not fully resemble those of natural wetlands over time, creation of these sites can still benefit landscape level diversity.
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The accelerated development of industrial activities in Taza City implies the appearance of new sources of pollution that directly affect the quality of surface water. This is reflected in the structure and biodiversity of the city’s Oueds, particularly Oued Lârbaa, which receives the majority of the pollution load produced. Therefore, the study of the benthic fauna can be an effective tool to characterize the state of the waters of Oued Lârbaa. The objective of our study is to assess the impact of anthropogenic activities on Oued Lârbaa, through the monitoring of physicochemical parameters (hydrogen potential (pH), salinity, conductivity, total dissolved solids (TDS), and oxidation–reduction potential) and biological biodiversity represented by benthic macroinvertebrates at 10 stations, during two periods of the year: a wet period (December 2018) and a dry period (June 2019). The spatial variations of recorded physicochemical parameters, as well as the effect of anthropogenic activities, control the diversity of macroinvertebrates at Oued Lârbaa. In relation to these data, the first stations of our study (S1-S2-S3) are moderately polluted, characterized by an important biodiversity, which includes sensitive species (Crustacea, Trichoptera, Ephemeroptera), and other resistant species (Diptera). The stations S4-S5-S6-S7-S8-S9 and S10 are characterized by a low biodiversity represented mainly by macroinvertebrates that colonize waters of critical quality (Diptera). The statistical study by principal component analysis consisting of a projection of the biological (benthic macroinvertebrates) and physicochemical variables obtained from each of the two study periods on a two-dimensional factorial plane shows the existing correlations between these variables.
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Lebak swamp in Bukit Baru has been lost largely degraded and lost through reclamation activity. Lebak swamp plays important role as land resource in Bukit Baru, Palembang. The study was sonducted to study the composition of Odonata in lebak swamps in Bukit Baru, Palembang, Indonesia. The transect line (1 km) was used to collect odonata in the study area. This study recorded 8 species during the study period. 8 species were found at Site A1, 6 species at site A2, 3 species at site A3, and 6 species at site A4. The highest diversity of odonata was found in site A1, however the other sites have lower odonata diversity. The highest abundance of odonata was recorded at site A2 and A4 and dominated by Ceriagrion coromandelianum and Orthetrum sabina. Neurothemis ramburii had the lowest abund ance at site A1 and A2, but absent at site A3 and A4. The occurrence of odonate species are lower at site around anthropogenic activity suggests the need to protect the lebak swamp so that such uncommon species will not go into local extinction. Neurothemis ramburii can become potential species to evaluate the rate of disturbed environment.
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Water quality data should be examined carefully before assigning a cause and effect relationship between cattle grazing and non point pollution. Natural background levels of nutrient and pathogen loading can be quite high during storm events. Non point pollution from pastured and rangeland livestock depends on the stock rate, length of grazing period, the season of use, manure deposition sites and concentration. Normally, pastures and rangelands have not presented water quality problems caused by cattle excrement, except under special circumstances. The main water quality concerns are from cattle feces and urine deposited directly into the water. Potential problems occur in cases where animals congregate for feeding, watering, resting, in proximity to waters. There is little scientific evidence that excrement from beef cattle on rangelands significantly impacts water quality. When significant nutrient contaminations do occur, especially phosphorus, they are more likely explained by erosion and sediment processes in the watershed. Cattle can effect the erosion and sediment process through vegetation removal. The scientific evidence implicating beef cattle as a significant source of C. Parvum or G. duodenalis for surface water contamination. Rangeland beef cattle excrement may increase pathogen contamination in water ways beyond background levels, but studies have shown that background levels are not zero. Wildlife species, including muskrats, coyotes, mule deer, waterfowl, elk, etc. shed pathogenic bacteria such as Campylobacter jejuni. Giardia has been repeatedly isolated from wildlife. Furthermore, high counts of indicator bacteria are often found upstream from grazed areas and are attributed to wildlife. Rangeland water quality can be managed by implementing spatial distribution of cattle through salting, upland water developments, fences for pasture rotation, and even by training or selection of the cattle grazed. These methods address the deposition of excrement near waterways, and also other, hydrologic, ecologic, and economic issues.
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Mapping of biodiversity elements to expose gaps in conservation networks has become a common strategy in nature-reserve design. We review a set of critical assumptions and issues that influence the interpretation and implementation of gap analysis, including: (1) the assumption that a subset of taxa can be used to indicate overall diversity patterns, and (2) the impact of uncertainty and error propagation in reserve design. We focus our review on species diversity patterns and use data from peer-reviewed literature or extant state-level databases to test specific predictions implied by these assumptions. Support for the biodiversity indicator assumption was varied. Patterns of diversity as reflected in species counts, coincidence of hot spots, and representativeness were not generally concordant among different taxa, with the degree of concordance depending on the measure of diversity used, the taxa examined, and the scale of analysis. Simulated errors in predicting the occurrence of individual species indicated that substantial differences in reserve-boundary recommendations could occur when uncertainty is incorporated into the analysis. Furthermore, focusing exclusively on vegetation and species distribution patterns in conservation planning will contribute to reserve-design uncertainty unless the processes behind the patterns are understood. To deal with these issues, reserve planners should base reserve design on the best available, albeit incomplete, data; should attempt to define those ecological circumstances when the indicator assumption is defensible; should incorporate uncertainty explicitly in mapped displays of biodiversity elements; and should simultaneously consider pattern and process in reserve-design problems.
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