Pyrosequencing of prey DNA in reptile faeces: analysis of earthworm consumption by slow worms

Little quantitative ecological information exists on the diets of most invertebrate feeding reptiles, particularly nocturnal or elusive species that are difficult to observe. In the UK and elsewhere, reptiles are legally required to be relocated before land development can proceed, but without knowledge of their dietary requirements, the suitability of receptor sites cannot be known. Here, we tested the ability of non-invasive DNA-based molecular diagnostics (454 pyrosequencing) to analyse reptile diets, with the specific aims of determining which earthworm species are exploited by slow worms (the legless lizard Anguis fragilis) and whether they feed on the deeper-living earthworm species that only come to the surface at night. Slow worm faecal samples from four different habitats were analysed using earthworm-specific PCR primers. We found that 86% of slow worms (N=80) had eaten earthworms. In lowland heath and marshy/acid grassland, Lumbricus rubellus, a surface-dwelling epigeic species, dominated slow worm diet. In two other habitats, riverside pasture and calciferous coarse grassland, diet was dominated by deeper-living anecic and endogeic species. We conclude that all species of earthworm are exploited by these reptiles and lack of specialization allows slow worms to thrive in a wide variety of habitats. Pyrosequencing of prey DNA in faeces showed promise as a practical, rapid and relatively inexpensive means of obtaining detailed and valuable ecological information on the diets of reptiles.     

Geographic and ecological patterns in Turkish land snails

The distribution of Turkish land snails has been examined, using data from a monograph by H. Schütt (1993). Turkey has been divided into eight regions for purposes of describing localization of fauna. On average, species occupy 1.7 regions. About 36% of the fauna is known from Turkey alone. There are affinities with Europe, the Caucasus, the eastern Mediterranean and the Levant and Middle East. The influence of neighbouring faunas shows up when the similarities of the eight regions are clustered. As usual, the fauna contains a high spired and a discoidal mode of shell shape, with species covering a wide range of sizes. Clausiliacea occupy a higher mode than other high spired species, while Helicacea become progressively more equidimensional from small to large species. The pattern of shell size and shape varies between regions, smaller and high spired species being most common in cooler and damper parts, larger discoidal species in parts with Mediterranean or continental dry climates. A test for evidence that animals of the same shape and size are more likely to be allopatric than sympatric failed to show that they were. The fauna is dominated by a few families to a greater extent than that of Europe, and is more like that of the isolated Madeiran archipelago. It is suggested that the Turkish fauna still shows evidence of external penetration with some local radiation, in the manner of the oceanic islands, and has not evolved to become a balanced assemblage such as is seen in Europe.     

Taxon-specific PCR for DNA barcoding arthropod prey in bat faeces

The application of DNA barcoding to dietary studies allows prey taxa to be identified in the absence of morphological evidence and permits a greater resolution of prey identity than is possible through direct examination of faecal material. For insectivorous bats, which typically eat a great diversity of prey and which chew and digest their prey thoroughly, DNA-based approaches to diet analysis may provide the only means of assessing the range and diversity of prey within faeces. Here, we investigated the effectiveness of DNA barcoding in determining the diets of bat species that specialize in eating different taxa of arthropod prey. We designed and tested a novel taxon-specific primer set and examined the performance of short barcode sequences in resolving prey species. We recovered prey DNA from all faecal samples and subsequent cloning and sequencing of PCR products, followed by a comparison of sequences to a reference database, provided species-level identifications for 149/207 (72%) clones. We detected a phylogenetically broad range of prey while completely avoiding detection of nontarget groups. In total, 37 unique prey taxa were identified from 15 faecal samples. A comparison of DNA data with parallel morphological analyses revealed a close correlation between the two methods. However, the sensitivity and taxonomic resolution of the DNA method were far superior. The methodology developed here provides new opportunities for the study of bat diets and will be of great benefit to the conservation of these ecologically important predators.     

Analysis of Australian fur seal diet by pyrosequencing prey DNA in faeces

DNA-based techniques have proven useful for defining trophic links in a variety of ecosystems and recently developed sequencing technologies provide new opportunities for dietary studies. We investigated the diet of Australian fur seals ( Arctocephalus pusillus doriferus ) by pyrosequencing prey DNA from faeces collected at three breeding colonies across the seals' range. DNA from 270 faecal samples was amplified with four polymerase chain reaction primer sets and a blocking primer was used to limit amplification of fur seal DNA. Pooled amplicons from each colony were sequenced using the Roche GS-FLX platform, generating > 20 000 sequences. Software was developed to sort and group similar sequences. A total of 54 bony fish, 4 cartilaginous fish and 4 cephalopods were identified based on the most taxonomically informative amplicons sequenced (mitochondrial 16S). The prevalence of sequences from redbait ( Emmelichthys nitidus ) and jack mackerel ( Trachurus declivis ) confirm the importance of these species in the seals' diet. A third fish species, blue mackerel ( Scomber australasicus ), may be a more important prey species than previously recognised. There were major differences in the proportions of prey DNA recovered in faeces from different colonies, probably reflecting differences in prey availability. Parallel hard-part analysis identified largely the same main prey species as did the DNA-based technique, but with lower species diversity and no remains from cartilaginous prey. The pyrosequencing approach presented significantly expands the capabilities of DNA-based methods of dietary analysis and is suitable for large-scale diet investigations on a broad range of animals.     

Australian land snails: a review of ecological research and conservation approaches

Land snails are an important yet often neglected component of Australia's biological diversity. Despite high levels of diversity within this group and the identification of many narrow range endemic species as being of conservation concern, there have been few detailed studies that document the ecology and conservation requirements of the group. A range of threats has been suggested, yet relatively few have been rigorously assessed. Whilst factors such as land clearing are readily apparent and have resulted in extinctions, other threats such as climate change are not well understood. This paper reviews studies conducted on terrestrial molluscs in Australia and highlights the need for further targeted ecological research, given the likely level of on-going threats. We urge researchers to apply rigorous approaches to data collection that will enable a deeper understanding of the factors governing distribution and abundance. Approaches used in other areas of conservation biology offer considerable scope for application to land snails and for the development of appropriate conservation strategies.     

Layers of contingency shroud pervasive ecological divergence in a local radiation of land snails

The predictability of evolution depends on the roles that selection and historical contingency play in determining its outcomes, but the relative importance of these evolutionary mechanisms has attracted considerable debate. One view is that historical events have such a profound impact on the genetic structure of populations that patterns of phenotypic evolution are essentially unpredictable. The opposing view is that selection is so powerful that evolutionary change is primarily deterministic, and thus highly predictable. By controlling for the effects of phylogeny, geographic location and habitat, this study examined the relative roles of contingency and determinism in a local radiation of land snails, genus Rhagada, in a continental archipelago. Informed by previous studies on a single island, which revealed a strong association between low‐spired shells and rocky habitats, 28 population pairs were sampled in directly adjoining rocky and spinifex plain habitats. When considered in their respective pairs, the effect of habitat was remarkably consistent, with lower‐spired shells observed in the rocky habitat in 24 of the comparisons. However, when analyzed outside the context of those pairs, the association was obscured by broad variation in shell shape within habitat types and among lineages. These results reveal the complex nature of a morphological radiation; while the pattern of ecological divergence is highly predictable at the scale that selection acts, deterministic evolution is largely obscured by phylogenetic and population history.     

Responses of a carnivorous plant to prey and inorganic nutrients in a Mediterranean environment

We have analysed the effect of prey and fertilization by inorganic nutrients on the survival, growth, reproduction (sexual and vegetative) and mucilage secretion of Pinguicula vallisneriifolia (Lentibulariaceae), a carnivorous plant inhabiting rocky substrates of southern Spain. We tested the hypothesis that carnivorous plants are more prey dependent when root access to nutrients is strongly limited by (1) analysing the importance of the carnivorous habit to the fitness of P. vallisneriifolia in its natural rocky habitat, and (2) determining whether the effect of trapped prey varies with soil nutrient levels. Our 2-year experimental results indicated prey to be limiting to P. vallisneriifolia growth on its natural rocky substrate. Animal food supply substantially increased the chance of survival, growth, vegetative propagation, sexual reproductive success and mucilage secretion. The differences between prey levels were more evident at the end of the experiment when all the surviving Prey-exclusion plants had lost weight, and the probability of sexual reproduction and of vegetative propagation by axillary buds had accordingly diminished. Furthermore, there were clear benefits from carnivory at the population level, since both the expected individual life span and the lifetime vegetative and sexual output correlated positively with the quantity of prey trapped. Application of insects to non-fertilized plants stimulated growth, but similar application to fertilized plants grown on a complete nutrient solution failed to enhance growth. There was no obvious benefit from the provision of a balanced mineral nutrient solution (alone or with prey). The greatest absolute growth and sexual and vegetative output resulted from providing a surplus of insects to plants on their natural rocky substrate. The strong dependence of P. vallisneriifolia on prey can therefore be considered a useful preadaptation enabling colonization of rocky substrates. Received: 11 November 1996 / Accepted: 31 March 1997     

Resistance to desiccation and distribution patterns in bush-dwelling land snails

Bush-dwelling land snails are exposed to desiccating conditions that are more severe than those of snails that seek the shelter of rock crevices, litter or the upper layers of the soil. We studied the resistance to desiccation in four bush-dwelling species of Israeli snails to evaluate a possible relation between their water economy and their distribution pattern. The resistance to desiccation decreased in the following order: Xeropicta vestalis (a widely distributed Mediterranean species), Trochoidea simulata (a desert species), Theba pisana (a Mediterranean species from the sand dunes of the coastal plain), and Monacha haifaensis (a Mediterranean species). Xeropicta vestalis also had the quickest response to the desiccating conditions. It is probably prevented from establishing itself in the desert, in spite of its superior water economy, because it is an annual, semelparous species, and the desert is a highly unpredictable environment. An immediate response to desiccating conditions may be a key factor in the success of desert-inhabiting land snails. Snails from more humid regions take several days to recruit their water preserving mechanisms, a delay which may be crucial to their water balance. The conchiometrics of X. vestalis and T. simulata suggest that the main water preserving mechanisms of these species are located in the mantle, rather than in the shell and epiphragm.     

DNA barcoding of stylommatophoran land snails: a test of existing sequences

DNA barcoding has attracted attention because it is a potentially simple and universal method for taxonomic assignment. One anticipated problem in applying the method to stylommatophoran land snails is that they frequently exhibit extreme divergence of mitochondrial DNA sequences, sometimes reaching 30% within species. We therefore trialled the utility of barcodes in identifying land snails, by analysing the stylommatophoran cytochrome oxidase subunit I sequences from GenBank. Two alignments of 381 and 228 base pairs were used to determine potential error rates among a test data set of 97 or 127 species, respectively. Identification success rates using neighbour‐joining phylogenies were 92% for the longer sequence and 82% for the shorter sequence, indicating that a high degree of mitochondrial variation may actually be an advantage when using phylogeny‐based methods for barcoding. There was, however, a large overlap between intra‐ and interspecific variation, with assignment failure (per cent of samples not placed with correct species) particularly associated with a low degree of mitochondrial variation (Kimura 2‐parameter distance < 0.05) and a small GenBank sample size (< 25 per species). Thus, while the optimum intra/interspecific threshold value was 4%, this was associated with an overall error of 32% for the longer sequences and 44% for the shorter sequences. The high error rate necessitates that barcoding of land snails is a potentially useful method to discriminate species of land snail, but only when a baseline has first been established using conventional taxonomy and sample DNA sequences. There is no evidence for a barcoding gap, ruling out species discovery based on a threshold value alone.     

新时期我国国土空间生态修复理念与模式探讨

国土空间生态修复以地理学、景观生态学理论为基础,是推进生态文明、建设美丽中国的重要举措.我国国土空间生态修复呈现理论体系多学科化、工作模式多元化、技术方法融合化、实践探索多样化的特征,工作总体成效显著与任务艰巨并存.本文基于国土空间生态修复的新挑战,对国土空间生态修复研究的总体框架和技术路径、区域国土空间生态修复的工作...     

A practical technique for non-destructive monitoring of soil surface invertebrates for ecological restoration programmes

Summary This study investigates the suitability of using wooden discs as facsimiles for natural fallen logs to non‐destructively monitor invertebrates. Wooden discs cut from tree trunks were placed on the ground at five sites and monitored. A diverse range of species was found under the discs including large numbers of some species. On Quail Island, Pine, Macrocarpa, Oak and Beech discs were compared. Beech discs had significantly fewer invertebrates and recognizable taxonomic units than other disc types. Pine discs had significantly more flatworms than the other three disc types. A comparison of invertebrate numbers when discs were placed directly on soil or grass indicated that larger numbers of individuals and recognizable taxonomic units were found under discs placed on bare soil compared with those on grass. Discs with a soil cavity beneath had significantly fewer individuals and recognizable taxonomic units than discs without cavities. Carabids showed considerable seasonal variation, with highest numbers in spring and lowest in winter, and larger numbers were found under discs at moist sites. Skinks over‐wintered under discs in drier open sites at Lincoln and Quail Island. Disc condition was assessed after 28 months and showed Macrocarpa had deteriorated the most of the four disc types. Wooden discs are a useful tool for the ecological management of terrestrial invertebrate fauna in restoration programmes for monitoring and considerable potential exists for discs to provide habitat for restoration of terrestrial invertebrate taxa.     

Spatio-temporal changes of photosynthesis in carnivorous plants in response to prey capture,retention and digestion

Carnivorous plants have evolved modified leaves into the traps that assist in nutrient uptake from captured prey. It is known that the traps of carnivorous plants usually have lower photosynthetic rates than assimilation leaves as a result of adaptation to carnivory. However, a few recent studies have indicated that photosynthesis and respiration undergo spatio-temporal changes during prey capture and retention, especially in the genera with active trapping mechanisms. This study describes the spatio-temporal changes of effective quantum yield of photochemical energy conversion in photosystem II (Φ_PSII) in response to ant-derived formic acid during its capture and digestion.Key words: action potential, carnivorous plants, formic acid, photosynthesis, respiration, animal-plant interactionCarnivorous plants have evolved their leaves into the modified structures called traps, which assist in nutrient uptake from prey bodies.¹ The traps attract, catch and digest the animal prey; however, some species obtain substantial amount of nutrients from leaf litter (Nepenthes ampullaria), algae (Utricularia) or from faeces of tree shrew Tupaia montana (Nepenthes lowii, N. rajah, N. macrophylla) as a result of adaptive radiation with regard to nitrogen sequestration.^2–5 Carnivorous plants are mainly restricted to sunny, moist and nutrient-poor environment, because only in this environment would the cost of producing traps be lower than the benefits gained from prey.⁶ From carbon metabolism point of view, the benefit is in term of increased rate of photosynthesis per unit leaf mass as a result of increased nitrogen concentration in the leaf or an increase in the total leaf mass that can be supported.^6–8 The costs of carnivory include reduced rate of net photosynthesis (A_N) in traps as a result of leaf adaptation to carnivory or increased rate of respiration (R_D) as a result of extra energy requirements for attracting, capturing and digesting the prey.⁹ Whereas the reduced A_N in the traps has been confirmed several times, the higher R_D in traps is still ambiguous.^9–12Until now studies assessing the cost of carnivory have usually been confined to measurements of A_N and R_D in carnivorous traps vs. non-carnivorous leaves, to the construction costs and payback times for carnivorous organs or to the carbon costs of sticky mucilage secretion by glands.^9–16 There is a growing body of evidences that prey-catching is active process involving spatio-temporal changes in A_N and R_D in traps, at least in carnivorous plants with active trapping mechanisms.¹⁷ First evidence, however not convincing, came from the work of Knight.⁹ She found that bladders of aquatic bladderwort Utricularia macrorhiza had a slightly greater R_D (10%) than assimilation leaves, but these differences were not significant. Later Adamec found that R_D of bladders in six Utricularia species was 75–200% greater than that in the leaves.¹⁸ The action of Utricularia bladder is one of the fastest movement in plant kingdom. When the trap of Utricularia is set, ready for trapping, it looks shrunken due to negative hydrostatic pressure. When the trapdoor is stimulated by prey it opens, sucks the water with prey and the door rapidly shuts. This firing process takes about 30 ms. Then the bladder restores its negative hydrostatic pressure by the removal of water from trap lumen through the glands. The resetting of bladders is a respiration-dependent process accompanied by the consumption of ATP.^1,19,20 Adamec suggests that the bladders of Utricularia were in post-firing state and were therefore pumping water and is possible that their R_D in this state was much higher than in their resting state.¹⁸ Adaptative changes in cytochrome c oxidase in the genus Utricularia may provide respiratory power for bladder function.²¹ The most famous carnivorous plant the Venus flytrap (Dionaea muscipula) also uses active trapping mechanism for prey capture. Recently, Hájek and Adamec published that the traps of D. muscipula had lower A_N, whereas the R_D in lamina and trap was comparable.¹² This is in accordance with the classical interpretation of cost/benefit model of carnivory. However, in our previous study we have shown that trigger hair irritation in the open as well as in closed trap of Dionaea muscipula resulted in the rapid increase of R_D and decrease of effective quantum yield of photochemical energy conversion in photosystem II (Φ_PSII).¹⁷ We have suggested that this is a result of generation of action potentials upon trigger hair irritation.^22–25The link between electrical signals and inhibition of photosynthesis and stimulation of respiration has been described in several plant species, however it has not been known in carnivorous plants.^26–30 Another genus of carnivorous plants that generates action potentials in response to mechanical irritation is sundew (Drosera). In the Dionaea traps, the action potential originates in any one of the six trigger hair and the potential propagates over the entire trap blade more rapidly across the lower (abaxial) surface. In the Drosera tentacle, action potentials are initiated by a receptor potential just below the swollen head of the tentacle and propagate only to its base and do not reach the leaf lamina.^31–33 This is in accordance with the results that separated D. prolifera tentacles have many times greater R_D in comparison with that of leaf lamina. This proves a very high metabolic and physiological activity of tentacles probably as a results of electrical irritability.¹¹ It has been suggested that at least some of the energy connected with the rise of R_D after action potential is utilized for the restoration of the state of ionic balance (i.e., restore the resting state).²⁶ Except the electrical signals, chemical substances seem to be also effective in effecting photosynthesis in carnivorous plants. This study describes negative impact of ant-derived formic acid on effective quantum yield of photochemical energy conversion in PSII (Φ_PSII), which is a sensitive indicator of plant photosynthetic performance.We measured the chlorophyll fluorescence in response to prey capture (ant Lasius niger L.) by the leaf of Drosera capensis L. Ten one-year-old Drosera capensis L plants were grown in growth chamber at a irradiance 200 µmol m⁻² s⁻¹ photosynthetic active radiation (PAR), 14/10 h day/night cycle and daily temperature ∼25°C. Before the measurement, the plant was adapted to light intensity 100 µmol m⁻² s⁻¹ PAR for 10 minutes (time required for steady state values of chlorophyll fluorescence in light-adapted state, F_t). The actinic light was provided by fluorcam FC-1000 LC (Photon System Instruments, Czech Republic) using red emitting LED diodes (λ = 620 nm). The experiment started by application of first saturation pulse (4,000 µmol m⁻² s⁻¹ PAR, 800 ms duration, λ = 620 nm). Then (after 10 seconds) one ant (Lasius niger) was gently put on the D. capensis leaf. During the first two hours, saturation pulses were applied every three minute, thereafter every hour and later every 24 hour. After each saturation flash the visible pictures were taken by camera Nikon D60 (Nikon, Thailand). The Φ_PSII, which indicates the proportion of the light absorbed by chlorophyll associated with photosystem II that is used in photochemistry, was calculated as (F_m′ - F_t)/F_m′.^34,35 The experiment was repeated without ant''s abdomen (the abdomen was cut by scalpel but ants survive and their moving was not affected). In the last experiment 1 µL 15 M formic acid (Fluka) was dropped on the leaf. All experiments were repeated four times independently and data presented are representative.The inhibition of Φ_PSII occurred within a few minutes after the ant was trapped by Drosera tentacles and then again after 96 hours (Fig. 1). Repeating the experiment without ant''s abdomen had no negative impact on Φ_PSII in spite of ant-induced leaf folding (Fig. 2). The most common substance in ant''s abdomen is formic acid.³⁶ This indicates that the inhibition of Φ_PSII was caused first by the spraying of the formic acid on the leaf by the struggling ant and then by releasing the formic acid after 96 hours from ant''s abdomen as a result of digestion. Therefore, the preliminary observation in Drosera mentioned at the end of discussion of our previous study was not associated with electrical signals.¹⁷ The inhibition was caused by the ant Lasius niger, which inhibits the Φ_PSII in D. capensis by releasing the formic acid from its abdomen. This is consistent with the findings that propagation of action potentials in Drosera is restricted only to the tentacles and therefore had no effect on photosynthesis in leaf blade (Fig. 2). Further, application of 1 µL 15 M formic acid resulted in very similar effect like the living ant with intact abdomen (Fig. 3). The concentration of formic acid was chosen according to data that the venom of Formica rufa contains 5–17 M formic acid.³⁶Open in a separate windowFigure 1The visible response (A) and the response of effective quantum yield of photochemical energy conversion in photosystem II (Φ_PSII, B) of Drosera capensis leaf to prey capture (intact ant Lasius niger). The ant was put on the leaf in time 10 seconds.Open in a separate windowFigure 2The response of effective quantum yield of photochemical energy conversion in photosystem II (Φ_PSII) of Drosera capensis leaf to prey capture (ant Lasius niger without abdomen). The ant without abdomen was put on the leaf in time 10 seconds. Note that no changes in Φ_PSII occurred in spite of leaf folding.Open in a separate windowFigure 3The response of effective quantum yield of photochemical energy conversion in photosystem II (Φ_PSII) of Drosera capensis leaf to 1 µL of 15 M formic acid. The drop of formic acid was put on the leaf in time 10 seconds.The production of formic acid by ants is thought to have evolved to improve capture of invertebrate prey and aid colony defence.³⁷ Some examples document that negative effect of ant-derived formic acid on plant growth is not novel, but it has not been described in carnivorous plants previously. It is known that ants Myrmelachista schumanni use formic acid as a herbicide. The ants live inside the hollow stems of Duroia hirsuta, kill all plants other than their host plant by injecting formic acid into the leaves. By killing these others plants, the ants gain more nest sites and they create a single species stand of plants.³⁸ Also, weaver ants (Oecophylla smaragdina) damage mango fruit by deposition of formic acid as a result of fighting between weaver colonies.³⁹The mechanism of action is very similar to the well known herbicide 3-(3,4-dichlorophenyl)-1,1-dimethylurea (DCMU). Formic acid causes significant inhibition of the electron transfer on the acceptor side of photosystem II, particularly from plastoquinone A to plastoquinone B.^40,41 From the data analysis of carnivorous plants published recently the genera with the highest proportions of ants in their diets are Brocchinia (90%), Nepenthes (73%) and Sarracenia (55%).⁴² All the mentioned genera have pitcher traps, with the permanent level of digestive fluid, in which the formic acid is diluted during digestion and thus the pitchers are probably prevented against its toxic effect. Captures of ants is much less frequent for sticky traps of Drosera (3.4%) and Pinguicula (0.5%); however it may have deteriorate effect.Carnivorous plants are not just killers but are a fascinating group of plant. They do not just eat the animals but may form a complicated social network with them. Complicated animal-plant interaction, as has been described e.g. between carnivorous pitcher plant Nepenthes bicalcarata and ants may have direct impact on physiological processes similar as a well known relationship between acacia and ants.⁴³ The possible impact of formic acid of ant species co-occurring with carnivorous plants in their natural habitat on photosynthesis remains to be elucidated.     

Heat shock proteins and resistance to desiccation in congeneric land snails

Land snails are subject to daily and seasonal variations in temperature and in water availability and depend on a range of behavioral and physiological adaptations for coping with problems of maintaining water, ionic, and thermal balance. Heat shock proteins (HSPs) are a multigene family of proteins whose expression is induced by a variety of stress agents. We used experimental desiccation to test whether adaptation to different habitats affects HSP expression in two closely related Sphincterochila snail species, a desiccation-resistant, desert species Sphincterochila zonata, and a Mediterranean-type, desiccation-sensitive species Sphincterochila cariosa. We examined the HSP response in the foot, hepatopancreas, and kidney tissues of snails exposed to normothermic desiccation. Our findings show variations in the HSP response in both timing and magnitude between the two species. The levels of endogenous Hsp72 in S. cariosa were higher in all the examined tissues, and the induction of Hsp72, Hsp74, and Hsp90 developed earlier than in S. zonata. In contrary, the induction of sHSPs (Hsp25 and Hsp30) was more pronounced in S. zonata compared to S. cariosa. Our results suggest that land snails use HSPs as part of their survival strategy during desiccation and as important components of the aestivation mechanism in the transition from activity to dormancy. Our study underscores the distinct strategy of HSP expression in response to desiccation, namely the delayed induction of Hsp70 and Hsp90 together with enhanced induction of sHSPs in the desert-dwelling species, and suggests that evolution in harsh environments will result in selection for reduced Hsp70 expression.     

Metabolism of cholecalciferol in land snails.

1. Radioactively labelled cholecalciferol was injected into the land snails Levantina hiersolyma and Theba pisana. Three metabolites (C, D and E), more polar than cholecalciferol, were found. 2. Metabolite C was found to be identical with 25-hydroxycholecalciferol. On injection of 25-hydroxy[26,27-3H]cholecalciferol, metabolite E was predominantly formed. Metabolite D was predominantly formed from cholecalciferol. Metabolites D and E differ from any known cholecalciferol metabolites. 3. The intestine was found to be the tissue capable of carrying out the transformation of 25-hydroxycholecalciferol into metabolite E. 4. 25-Hydroxycholecalciferol and metabolite E were localized in the digestive gland of the snail, the tissue responsible for the absorption of Ca2+ and its storage. Metabolite D was not localized in any specific tissue.     

Cold-hardiness in several species of land snails

1. 1.|Mean supercooling points (SCP) of Anguispira alternata (Say) gradually declined in autumn and increased in spring. SCP also declined in autumn in Discus conrkhitei (Newcomb) and Gastrocopta armifera (Say).

2. 2.|Supercooling ability varied among the species, being the greatest in G. armifera.

3. 3.|Prolonged exposure of winter animals to high temperatures resulted in only a modest increase in SCP.

4. 4.|Low temperature survival of D. cronkhitei and G. armifera was slightly poorer than predicted by the mean SCP.

Contribution of genetics to ecological restoration

Ecological restoration of degraded ecosystems has emerged as a critical tool in the fight to reverse and ameliorate the current loss of biodiversity and ecosystem services. Approaches derived from different genetic disciplines are extending the theoretical and applied frameworks on which ecological restoration is based. We performed a search of scientific articles and identified 160 articles that employed a genetic approach within a restoration context to shed light on the links between genetics and restoration. These articles were then classified on whether they examined association between genetics and fitness or the application of genetics in demographic studies, and on the way the studies informed restoration practice. Although genetic research in restoration is rapidly growing, we found that studies could make better use of the extensive toolbox developed by applied fields in genetics. Overall, 41% of reviewed studies used genetic information to evaluate or monitor restoration, and 59% provided genetic information to guide prerestoration decision‐making processes. Reviewed studies suggest that restoration practitioners often overlook the importance of including genetic aspects within their restoration goals. Even though there is a genetic basis influencing the provision of ecosystem services, few studies explored this relationship. We provide a view of research gaps, future directions and challenges in the genetics of restoration.     

国土综合整治与生态修复对区域生态系统服务价值的影响评估

国土整治与生态修复对保障区域生态质量、优化生态安全格局和提升生态系统服务价值有积极的促进作用。定量化测算国土综合整治与生态修复对区域生态质量的影响是领域的研究热点和难点。以广西壮族自治区贺州市为例,提出了国土综合整治与生态修复对区域生态系统服务价值的影响评估方法,主要结论如下:(1)不同地类由于其质量不同,单位面积生态系统服务价值差距较大,研究提出了基于地类质量的单位面积生态系统服务价值确定方法,并据此测算了各地类通过整治修复质量的提升潜力;(2)贺州市整治修复前生态系统服务总价值为411.80亿元,经过评估,整治修复后生态系统服务总价值可以增加到458.06亿元,增加比例为11.23%。贺州市林地生态系统服务价值增加潜力最大,其次是草地、耕地。生态系统服务价值增加潜力在空间上呈现了东西两翼高于中部、南部地区高于东部地区的趋势;(3)贺州市各区县整治修复潜力差距较大,潜力最大的为八步区和昭平县,潜力提升比例最高的是富川县,不同区县可以根据结果确定整治修复的工程布局。研究结果对于区域国土空间整治与生态修复工程安排及整治修复绩效评估有重要的指导意义。