Home Range,Movement, and Distribution Patterns of the Threatened Dragonfly Sympetrum depressiusculum (Odonata: Libellulidae): A Thousand Times Greater Territory to Protect?

Dragonflies are good indicators of environmental health and biodiversity. Most studies addressing dragonfly ecology have focused on the importance of aquatic habitats, while the value of surrounding terrestrial habitats has often been overlooked. However, species associated with temporary aquatic habitats must persist in terrestrial environments for long periods. Little is known about the importance of terrestrial habitat patches for dragonflies, or about other factors that initiate or influence dispersal behaviour. The aim of this study was to reveal the relationship between population dynamics of the threatened dragonfly species Sympetrum depressiusculum at its natal site and its dispersal behaviour or routine movements within its terrestrial home range. We used a mark–release–recapture method (marking 2,881 adults) and exuviae collection with the Jolly–Seber model and generalized linear models to analyse seasonal and spatial patterns of routine movement in a heterogeneous Central European landscape. Our results show that utilisation of terrestrial habitat patches by adult dragonflies is not random and may be relatively long term (approximately 3 mo). Adult dragonflies were present only in areas with dense vegetation that provided sufficient resources; the insects were absent from active agricultural patches (p = 0.019). These findings demonstrate that even a species tightly linked to its natal site utilises an area that is several orders of magnitude larger than the natal site. Therefore, negative trends in the occurrence of various dragonfly species may be associated not only with disturbances to their aquatic habitats, but also with changes in the surrounding terrestrial landscape.     

Processes structuring amphibian assemblages along a subtropical arid gradient

Biotic assemblages are organized according to multiple factors, including environmental filtering and species interactions. However, the roles of abiotic and biotic factors in the organization of amphibian assemblages in arid regions are still not completely understood. Here, I examined the distribution patterns of seven species of amphibians that occur in Tunisia (north-western Sahara Desert) and the composition of 328 amphibian assemblages, including their meta-structural organization. The species showed different responses to environmental gradients, predominantly the aridity and vegetation gradients. The assemblages in xeric regions were composed of nested subsets of the species present in mesic regions. Most of the significant species associations were explained by shared environmental responses, indicating that they can be largely attributed to environmental filtering. The only exception was between two species of generalist bufonids, Bufotes boulengeri and Sclerophrys mauritanica, which showed a residual correlation greater than their shared association with the gradient. In this case, phylogenetic and morphological similarities could favour patterns of mutual exclusion in habitats such as desert oases, where the resources are limited.     

New gomphaeschnids and progobiaeshnids from the Yixian Formation in Liaoning Province (China) illustrate the tremendous Upper Mesozoic diversity of the aeshnopteran dragonflies

One new genus and five new species of dragonflies (Odonata) are described and figured from the Yixian Formation of northeastern China, viz. two gomphaeschnids Sinojoria magna nov. sp. and S. cancellosa nov. sp., plus three progobiaeshnids Mongoliaeshna hadrens nov. sp., M. exiguusens nov. sp., and Decoraeshna preciosus nov. gen., nov. sp. These new discoveries confirm the apparently sudden great diversification in China of the clade Aeshnoptera during the Middle-Upper Jurassic, together with the Upper Mesozoic to modern lineages of dragonflies. At the same time, some ‘ancient’ groups of Odonata became extinct.     

Conservation of a groundwater-dependent mire-dwelling dragonfly: implications of multiple threatening processes

Groundwater-dependent ecosystems and their dependent species are under increasing threat globally. Petalurid dragonflies are one such group. This review highlights processes that threaten the groundwater-dependent mire habitats of Petalura gigantea, a dragonfly with long-lived fossorial larvae. The species is reliant for successful reproduction on areas of emergent seepage, or at least, on a water table that is sufficiently high to cause saturation of the peaty substrate. These microhabitat characteristics are critical for successful oviposition and larval burrow establishment, making the species particularly vulnerable to any lowering of water tables. The effect of any lowering of water tables, due to groundwater abstraction or longwall coal mining, for example, will be compounded by the effects of more intense fire regimes in these mires and by projected climate change. These threatening processes act in conjunction with a range of other anthropogenic threats and are mirrored globally in threats to other groundwater-dependent mire ecosystems and their dependent species, including other petalurid dragonflies.     

Identifying adult dragonfly prey items using DNA barcoding and stable isotope analysis

Using DNA barcoding and stable isotope analysis, we identified adult dragonfly prey items from the fecal pellets of five dragonfly species—Nannophya pygmaea, Ischnura asiatica, Sympetrum eroticum, Orthetrum albistylum, and Anax parthenope—collected from a mountain bog located in south‐eastern South Korea. Twelve operational taxonomic units (OTUs) belonging to four orders, Coleoptera, Diptera, Hemiptera, and Lepidoptera, were identified as prey items of adult dragonflies using DNA barcoding. Among prey items, Dipterans were the most common, comprising seven of the 10 OTUs. Based on stable isotope analysis, adult dragonflies and their nymphs were among the most numerous predators in both aquatic and terrestrial habitats. Additionally, dragonfly species with smaller adult sizes had different isotopic compositions to those reaching larger adult sizes. Both δ¹⁵N and δ¹³C values were significantly lower in smaller species than in larger species, indicating differences in their trophic levels and carbon sources.     

Conservation potential of semi-natural habitats for birds in intensively-used agricultural landscapes

Agricultural intensification resulted in substantial loss of farmland biodiversity. Semi-natural habitats may be viewed as potential buffers of these adverse impacts, but a rigorous assessment of their capacity for supporting farmland biodiversity is lacking. In this study, we explored conservation potential of two different types of semi-natural habitats for birds in intensively-used agricultural landscapes – farmland hedges (i.e., linear strips of shrubby and tree vegetation) and open scrubland (i.e., scattered shrubs and abandoned orchards). Specifically, we tested whether the abundance and species richness of birds differ between these habitats considering various species traits, such as habitat affinity (i.e., forest, farmland and urban species), diet specialization (i.e., animal eaters, plant eaters, and omnivores) and conservation status (Species of European Conservation Concern). We found that open scrubland hosted on average 37.9 bird species and 122.6 individuals per 1 km² of the transect, whereas farmland hedges hosted only 19 species and 61.8 individuals per 1 km² of the transect. However, results have substantially changed if we considered the area of suitable habitat into account. More specifically, open scrubland hosted more bird species and individuals when we considered open habitat species and the area of open habitats, whereas farmland hedges had higher species diversity and individuals of woodland bird species when we considered the area of woodland habitats. Similarly, analyses of habitat affiliations of individual species corresponded to the whole-community patterns; and revealed that several woodland bird species were mainly associated with farmland hedges (e.g., Chaffinch Fringilla coelebs, Common Nightingale Luscinia megarhynchos and Blackcap Sylvia atricapilla), whereas the open scrubland was preferred by open habitat bird species (e.g., Corn Bunting Emberiza calandra, Quail Coturnix coturnix and Skylark Alauda arvensis). These results demonstrate that semi-natural habitats, both open scrubland and farmland hedges, have large potential for promotion and conservation of bird communities within intensively used agricultural landscapes, as both may have represented suitable habitats for species with different ecological requirements. Therefore, management measures focused on the enlargement of the area of these habitats, in combination with suitable management (e.g., regulating the progress of natural succession in open scrubland; increasing structural diversity of existing farmland hedges), may substantially contribute to bird conservation within agricultural landscapes.     

Does the management of surrounding terrestrial habitats increase the tendency of odonates to leave aquatic habitats?

Generally, dragonflies and damselflies (odonates) are considered aquatic invertebrates. However, the ecological requirements of their adults are not different from those of fully, terrestrial insects. Surprisingly, there is a very little information on whether the management and structure of surrounding habitats has any influence on the diversity and seasonal dynamics of odonates. This is important to know because recently, a large proportion of freshwater habitats in Central Europe have becomes surrounded by intensively managed habitats. The aim of this study was to investigate the effects of different types of terrestrial habitats on their long-term utilization by dragonflies and damselflies. I assumed that this pattern varied over time; therefore, I used generalized additive mixed models to analyze the effects of management on seasonal changes in the abundance of individuals in terrestrial environments. From my results, it was evident that the management practices of surrounding terrestrial habitats had a significant impact on the population dynamics of dragonflies. The abundance of dragonfly adults in surrounding terrestrial habitats increased toward the end of the season. However, this was only, when the natal aquatic habitat was not affected by fish farming and was able to supply surrounding terrestrial habitats with offspring. This was evidenced by the fact that, compared to areas with extensive water management, in sites with fish farming, seasonal increases in abundance was negligible. There is no doubt that the structure of surrounding terrestrial habitats has a significant influence on the diversity of terrestrial invertebrates. However, we must not forget that terrestrial habitats, regardless of their management, are not able to replace the poor quality of the aquatic (natal) habitat. Interestingly, the abundance of damselflies decreased toward the end of the season, regardless of the management practices of the surrounding areas. This indicates that their dynamics is more controlled by time stress or other similar mechanisms than that of dragonflies.     

High Tolerance to Salinity and Herbivory Stresses May Explain the Expansion of Ipomoea Cairica to Salt Marshes

Background

Invasive plants are often confronted with heterogeneous environments and various stress factors during their secondary phase of invasion into more stressful habitats. A high tolerance to stress factors may allow exotics to successfully invade stressful environments. Ipomoea cairica, a vigorous invader in South China, has recently been expanding into salt marshes.

Methodology/Principal Findings

To examine why this liana species is able to invade a stressful saline environment, we utilized I. cairica and 3 non-invasive species for a greenhouse experiment. The plants were subjected to three levels of salinity (i.e., watered with 0, 4 and 8 g L⁻¹ NaCl solutions) and simulated herbivory (0, 25 and 50% of the leaf area excised) treatments. The relative growth rate (RGR) of I. cairica was significantly higher than the RGR of non-invasive species under both stress treatments. The growth performance of I. cairica was not significantly affected by either stress factor, while that of the non-invasive species was significantly inhibited. The leaf condensed tannin content was generally lower in I. cairica than in the non-invasive I. triloba and Paederia foetida. Ipomoea cairica exhibited a relatively low resistance to herbivory, however, its tolerance to stress factors was significantly higher than either of the non-invasive species.

Conclusions/Significance

This is the first study examining the expansion of I. cairica to salt marshes in its introduced range. Our results suggest that the high tolerance of I. cairica to key stress factors (e.g., salinity and herbivory) contributes to its invasion into salt marshes. For I. cairica, a trade-off in resource reallocation may allow increased resources to be allocated to tolerance and growth. This may contribute to a secondary invasion into stressful habitats. Finally, we suggest that I. cairica could spread further and successfully occupy salt marshes, and countermeasures based on herbivory could be ineffective for controlling this invasion.     

An avifaunal survey of mesic manmade ecosystems “Oases” in algerian hot-hyperarid lands

Man made ecosystems of dry lands are key habitats due to their ecological characteristics to survey biodiversity. This study investigated bird diversity in three oases of the Northern Algerian Sahara (i.e., Biskra in 2006, Oued Souf in 2008 and Ouargla in 2009), by using the spot-mapping method. Bird density “D” (pairs/10 ha), species richness “S” (number species), diversity (Shannon index) “H′” (in bits), and evenness “E” varied from one oasis to another (Biskra: D = 98.5, S = 47, H′ = 4.49, E = 0.81; Oued Souf: D = 96, S = 33, H′ = 3.9, E = 0.77; Ouargla: D = 91.5, S = 44, H′ = 4.39, E = 0.80). Differences in bird diversity between the monitored palm groves are due to the ecological characteristics of each environment. Documented literature outlined close taxonomic similarities between bird assemblages of the study area with many Northern Saharan oases. The Hybrid Sparrow Passer domesticus x Passer. hispaniolensis and some Columbidae species including Columba livia, Streptopelia turtur, Streptopelia senegalensis, and Streptopelia decaocto were the abundant species throughout surveyed oases in which they represented more than half (55.6%) of the sum of species densities (D = 286 pairs/10 ha). These synthropic species have known a huge expansion of their distribution range throughout Algerian oases. The correspondence analysis allowed the aggregation of both families and species into oasis they belong to. One-way ANOVA was tested to analyse variations of both family and species densities between studied oases. The ANOVA revealed there was no significant variation either in family densities (p = 0.937) or in bird densities (p = 0.622) between the surveyed oases because of the small size of bird populations.     

Stictocardia tiliifolia (Convolvulaceae) re-evaluated

Stictocardia tiliifolia (Desr.) H. Hall. is accepted as the correct name for the type species ofStictocardia. An earlier name,Ipomoea campanulata L., regarded as a synonym of S.tiliifolia for the last 50 years, is found to be synonymous withIpomoea illustris (C. B. Clarke) Prain, a species occurring in coastal/tidal riverine habitats of South Asia. Material from interior habitats, calledI. campanulata by authors of Indian floras, is believed to represent a variety of trueI. campanulata or a closely related species.     

Dragonflies (Odonata) of thermal springs in Central Asia

Sixteen species of dragonflies were recorded in 12 thermal springs of Central Asia. Of these, Ischnura forcipata, I. pumilio, Orthetrum anceps, O. brunneum, and Sympetrum haritonovi were widely distributed in hydrothermal waters. In the high mountains of Pamir, dragonflies can develop only in hot springs. The maximum altitude recorded for the habitat of O. brunneum was 3950 m a.s.l.     

马鞍列岛多种生境中鱼类群聚的昼夜变化

为了解岛礁水域鱼类群聚的昼夜变化特征,以便更全面地设计采样方法和掌握采样的时间尺度,于2009年9月对马鞍列岛7种生境进行了共计24网次的刺网昼夜采样,结合排序和聚类方法,从种类组成、相对生物量和丰度、种类丰富度、多样性和相似性等方面对研究海域鱼类群聚特征的昼夜变化作了探讨.在采获的55种鱼类中,昼夜出现的分别为41和46种,数量差别不大,但其昼夜组成却随栖息水层的变化而不同,底层鱼类更趋向于夜间在硬相生境集群活动;近底层鱼类的昼夜集群随生境变化而变化,在同一生境中既有偏向白天也有趋向夜间的;中上层鱼类更多地出现在白天的人工生境(AH).AH白天的丰度渔获率显著大于晚上,而天然生境(NH)昼夜差别不大;生物量渔获率无论NH还是AH皆无显著昼夜差异.具体到种类,仅有小黄鱼Larimichthys polyactis和赤鼻棱鳗Thryssa kammalensis等少数种类的数量在AH有显著的昼夜差别,其他多数种类虽然昼夜的出现率大多有别,但渔获率昼夜差异皆不明显.多样性差异更多的表现在不同生境之间,而同一生境的昼夜差异往往不甚显著.各个生境中鱼类的昼夜种类交替现象非常明显,形成了以褐菖(鲐)Sebastiscus marmoratus和鳗鲇Plotosus anguillaris为代表的夜间优势类群为主的硬相生境群聚格局、以丝背细鳞鲀Stephanolepis cirrhifer和细刺鱼Microcanthus strigatus为代表的白天优势类群为主的硬相生境群聚格局以及缺乏底层优势类群、以石首鱼科鱼类为代表的近底层鱼类为绝对优势类群的软相生境群聚格局.因此,采用被动性渔具在近岸典型生境进行鱼类等相关生物调查时,应使采样时间覆盖昼夜两个时段,且至少保证24h.     

Effect of loach consumption on the reproduction of giant water bug Kirkaldyia deyrolli: dietary selection, reproductive performance, and nutritional evaluation

Rice fields provide major habitats for lentic aquatic insects including the giant water bug Kirkaldyia (=Lethocerus) deyrolli (Heteroptera: Belostomatidae) in Japan. Previous researchers have emphasized that conserving populations of the frogs, Hyla japonicus and Rana nigromaculata, is very important for preserving K. deyrolli because these frogs were found to be a major component of the diet of K. deyrolli adults. However, these previous studies were carried out in rice fields with no loaches, Misgurnus anguillicaudatus, which were probably been inhabited by loaches in the past. A series of field surveys and laboratory experiments were conducted to determine the dietary preference of K. deyrolli adults for loaches, frogs, and aquatic insects; the reproductive effects of consuming these foods; and their protein content. In the rice fields, K. deyrolli adults ate loaches when they were available. When the three prey species (frog: R. nigromaculata, loach: M. anguillicaudatus, and dragonfly: Orthetrum albistylum speciosum) were supplied in laboratory conditions, K. deyrolli adults ate more loaches than frogs or dragonflies. In addition, K. deyrolli adults provided with loaches or frogs laid more egg masses within the limited breeding season than when provided with dragonflies. The edible parts of the loach bodies were the largest of the three prey types. It is possible that K. deyrolli adults have been forced to eat frogs due to reductions in the population density of loaches because modern rice cultivation obstructs loach migration routes and reduces their spawning grounds.     

Ants of Three Adjacent Habitats of a Transition Region Between the Cerrado and Caatinga Biomes: The Effects of Heterogeneity and Variation in Canopy Cover

Habitat heterogeneity and complexity associated with variations in climatic conditions are important factors determining the structure of ant communities in different terrestrial ecosystems. The objective of this study was to describe the horizontal and vertical distribution patterns of the ant community associated with three adjacent habitats in a transition area between the Cerrado and Caatinga biomes at the Pandeiros River, state of Minas Gerais, Brazil. We tested the following hypotheses: (1) the richness and composition of ant species and functional group structure changes between different habitats and strata; (2) habitats with higher tree species richness and density support higher ant species richness; and (3) habitats with lower variation in canopy cover support higher ant species richness. Sampling was conducted in three adjacent habitats and at three vertical strata. Ant species richness was significantly different among vertical strata. Ant species composition was different among both habitats and vertical strata and functional group structure was divergent among habitats. Partitioning of the diversity revealed that the diversity for the three components was statistically different from the one expected by the null model; α and β ₂ were higher and β ₁ was lower than the values expected by chance. Tree density and variation in canopy cover negatively affected ant species richness. The occurrence of different species and the changing of functional group structures in different habitats and strata suggest an ecological–evolutionary relationship between ants and their habitats and emphasize the need to implement local conservation strategies in the ecotones between biomes.     

Potentialities of plants with underground storage organs in the Egyptian desert flora

Plants with underground storage organs in the natural flora of Egypt appeared promising as raw materials for various economic uses. As basic information for any future industrial, pharmaceutical, or agricultural uses, we must understand their inorganic constituents in relation to variations of habitats and life cycle events. Fourteen species have been collected from different habitats along the Mediterranean coast and examined for their chemical element composition and correlated with the environmental conditions. One of these species,Asphodelus microcarpus Salzm. and Viv., has been critically studied to determine the uptake and distribution of the different mineral elements during its different phenophases. The importance of this study on the rational uses of the different parts of this plant is discussed.     

Hidden in the mangrove forest: the cryptic intertidal mite Carinozetes mangrovi sp. nov. (Acari,Oribatida, Selenoribatidae)

The small archipelago of Bermuda is a geologically young landmass in the Western Atlantic Ocean and recently turned out to be inhabited by a number of intertidal oribatid mites. One newly described species, Carinozetes bermudensis, showed an unusual vast range of habitats like sandy beaches, rocky substrate and mangroves. In the present study, 13 Bermudian populations of C. bermudensis were analysed to verify species integrity of specimens from different microhabitats. A morphometric analysis of 17 continuous variables as well as a molecular genetic investigation of the mitochondrial cytochrome oxidase subunit I revealed the existence of a new species Carinozetes mangrovi sp. nov., inhabiting exclusively intertidal algae growing on mangrove roots. Although both species are morphologically nearly identical, the configuration of the genus-specific ventral carinae represents a clear diagnostic character. The high genetic divergence of approximately 12 % of the cytochrome oxidase subunit I gene sequence between C. bermudensis and C. mangrovi sp. nov. suggests that these two species diverged before the emergence of the Bermuda islands. Accordingly, both of them are older than the geologically young archipelago of Bermuda.     

Habitat requirements, short-term population dynamics and coexistence of native and invasive Impatiens species: a field study

The genus Impatiens (Balsaminaceae) includes three widespread species in the Czech Republic, central Europe: the native I. noli-tangere, and two invasive species, I. parviflora and I. glandulifera, differing in the dynamics of invasion. They all occur in similar habitats and share basic life-history characteristics, which make them a suitable model for studying species traits associated with invasiveness. In this study we investigated differences in habitat requirements of these Impatiens species, their coexistence and short-term population dynamics in the field. We established 84 1 × 1 m permanent plots in five localities where all three species co-occurred. In each plot vascular plant species were determined, their cover estimated and all individuals of Impatiens species counted. Site characteristics including tree canopy cover, soil moisture, nitrogen and carbon content, and slope were measured directly. Nutrients, light, humidity and soil reaction were estimated using Ellenberg indicator values. The presence of I. noli-tangere was strongly correlated with high soil moisture, that of I. parviflora with high tree canopy cover and low soil moisture. Impatiens glandulifera exhibited a unimodal response to tree canopy cover, avoiding both very shaded and fully open sites. The current-year abundances of all species were negatively related to those of congeneric species. These results suggest that the coexistence of Impatiens species in the same habitat is due to microsite differentiation. Further spread of I. glandulifera to new habitats, and reduction of the native I. noli-tangere niche, can be expected in areas where the latter species co-occurs with competitively strong invasive congeners.     

Determinant landscape‐scale factors on pond odonate assemblages

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Recording of Retinal Action Potentials from Single Cells in the Insect Compound Eye

Electrical responses were recorded intracellularly from the compound eyes of a fly (Lucilia) and of several dragonflies (Copera, Agriocnemis, and Lestes). An ommatidium of the dragonflies is made up of four retinula cells and a rhabdom composed of three rhabdomeres while the Lucilia has an ommatidium of seven independent retinula cells and rhabdomeres. The intracellular responses presumably recorded from the retinula cell had the same wave form in the two groups of insects: The responses were composed of two components or phases, a transient spike-like potential and a slow one maintained during illumination. The membrane potential, in the range of -25 to -70 mv., was influenced by the level of adaptation, and it was transiently depolarized to zero by high levels of illumination.     

贵州茂兰自然保护区蜻蜓多样性初步研究

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