Climate‐change impacts on sandy‐beach biota: crossing a line in the sand

Sandy ocean beaches are iconic assets that provide irreplaceable ecosystem services to society. Despite their great socioeconomic importance, beaches as ecosystems are severely under‐represented in the literature on climate‐change ecology. Here, we redress this imbalance by examining whether beach biota have been observed to respond to recent climate change in ways that are consistent with expectations under climate change. We base our assessments on evidence coming from case studies on beach invertebrates in South America and on sea turtles globally. Surprisingly, we find that observational evidence for climate‐change responses in beach biota is more convincing for invertebrates than for highly charismatic turtles. This asymmetry is paradoxical given the better theoretical understanding of the mechanisms by which turtles are likely to respond to changes in climate. Regardless of this disparity, knowledge of the unique attributes of beach systems can complement our detection of climate‐change impacts on sandy‐shore invertebrates to add rigor to studies of climate‐change ecology for sandy beaches. To this end, we combine theory from beach ecology and climate‐change ecology to put forward a suite of predictive hypotheses regarding climate impacts on beaches and to suggest ways that these can be tested. Addressing these hypotheses could significantly advance both beach and climate‐change ecology, thereby progressing understanding of how future climate change will impact coastal ecosystems more generally.     

A laboratory technique to speed processing of samples with large numbers of invertebrates

The amount of time needed to process samples with large numbers of terrestrial invertebrates in the laboratory has been a long‐standing obstacle impeding progress in invertebrate conservation biology and applied ecology. Laboratory subsampling of samples with large numbers of invertebrates is one method that saves time and reduces processing cost. In this study, a laboratory vacuum processing technique, consisting of a vacuum pump, aspirator and voice recognition software, was compared with a subsampling technique, and a conventional whole sample counting method. Vacuum processing was the most efficient technique; on average, more than five times more insects were processed per minute compared with whole sample counting and subsampling techniques. Differences in efficiencies among techniques were affected by trap type and invertebrate abundance. The vacuum technique was most efficient when processing high abundance pitfall trap samples, and was less efficient in processing pan trap samples that had invertebrates entangled by algae and other materials. Caution should be exercised when using the technique on soft‐bodied or poorly preserved specimens; a subsampling technique may be more appropriate in these cases, especially if specimens must be identified to genus or species level at a later time. The efficiency of the vacuum technique is reduced relative to the amount of time it takes to locate invertebrates in a sample; therefore, the technique does not save substantial time when processing samples with large amounts of substrate or debris, such as is the case with some aquatic invertebrate samples. However, if flotation or another method that separates invertebrates from other materials is used first, then the vacuum method would be useful for these types of samples as well.     

陆地生态系统中马陆的生态功能

马陆是陆地生态系统中物种多样性极高的大型土壤无脊椎动物类群。作为营腐生动物, 马陆在陆地生态系统中具有不可替代的重要功能。通过大量取食及随后的肠道过程, 马陆在很大程度上决定着陆地生态系统凋落物的破碎、转化和分解过程, 从而驱动碳和关键养分元素的循环周转。然而, 目前对马陆生态功能的研究还非常有限, 远远落后于其他土壤动物类群(如蚯蚓等)。本文初步总结了马陆的生态功能: (1)通过破碎、取食凋落物来加速凋落物的分解。马陆偏好取食半分解的凋落物, 其同化效率受到凋落物来源、温度和凋落物中微生物含量的影响。(2)主要通过取食和排泄等活动影响养分循环。但对于马陆如何影响土壤碳循环, 存在两种不同的观点: 一是马陆粪球的分解速率比凋落物更快, 加速了碳的循环; 二是马陆粪球更难分解, 有助于碳的固存和稳定。马陆破碎凋落物后, 凋落物释放氮素进入土壤。此外, 马陆的活动也影响土壤磷的循环, 提高土壤中有效磷的含量。(3)调控微生物特性, 与蚯蚓也有互作关系。通过以上三个方面的总结, 展望了未来马陆的主要研究方向, 以期引起更多思考和研究。     

Trans-generational immune priming is not mediated by the sex of the parent primed: a meta-analysis of invertebrate data

Traditionally, only vertebrates were thought capable of acquired immune responses, such as the ability to transfer immunological experience vertically to their offspring (known as trans-generational immune priming, TGIP). Increasing evidence challenges this belief and it is now clear that invertebrates also have the ability to exhibit functionally equivalent TGIP. This has led to a surge in papers exploring invertebrate TGIP, with most focusing on the costs, benefits or factors that affect the evolution of this trait. Whilst many studies have found support for the phenomenon, not all studies do, and there is considerable variation in the strength of positive results. To address this, we conducted a meta-analysis to answer the question: what is the overall effect of TGIP in invertebrates? Then, to understand the specific factors that affect its presence and intensity, we conducted a moderator analysis. Our results corroborate that TGIP occurs in invertebrates (demonstrated by a large, positive effect size). The strength of the positive effect was related to if and how offspring were immune challenged (i.e. whether they were challenged with the same or different insult as their parents or not challenged at all). Interestingly, there was no effect of the ecology or life history of the species or the sex of the parent or the offspring primed, and responses were comparable across different immune elicitors. Our publication bias testing suggests that the literature may suffer from some level of positive-result bias. However, even after accounting for potential bias, our effect size remains positive. Publication bias testing can be influenced by diversity in the data set, which was considerable in our data, even after moderator analysis. It is therefore conceivable that differences among studies could be caused by other moderators that were unable to be included in our meta-analysis. Nonetheless, our results suggest that TGIP does occur in invertebrates, whilst providing some potential avenues to examine the factors that account for variation in effect sizes.     

Promise and progress in environmental genomics: a status report on the applications of gene expression-based microarray studies in ecologically relevant fish species

The advent of any new technology is typically met with great excitement. So it was a few years ago, when the combination of advances in sequencing technology and the development of microarray technology made measurements of global gene expression in ecologically relevant species possible. Many of the review papers published around that time promised that these new technologies would revolutionize environmental biology as they had revolutionized medicine and related fields. A few years have passed since these technological advancements have been made, and the use of microarray studies in non‐model fish species has been adopted in many laboratories internationally. Has the relatively widespread adoption of this technology really revolutionized the fields of environmental biology, including ecotoxicology, aquaculture and ecology, as promised? Or have these studies merely become a novelty and a potential distraction for scientists addressing environmentally relevant questions? In this review, the promises made in early review papers, in particular about the advances that the use of microarrays would enable, are summarized; these claims are compared to the results of recent studies to determine whether the forecasted changes have materialized. Some applications, as discussed in the paper, have been realized and have led to advances in their field, others are still under development.     

Habitat, isolation and the evolution of Madeiran Iandsnails

The Madeiran archipelago consists of Madeira itself, Porto Santo and the Deserta islands. On Madeira, the forest arid the coastal floral associations are so different that their faunas are effectively isolated and have undergone largely independent development. There are different faunal associations on the eastern peninsula and in the SE coastal region, which may have been separated from each other in the past. On Porto Santo, western and eastern hills have different faunas. Most observations on the fauna are compatible with evolution by allopatric speciation, consequent upon isolation on different islands or mountains, as opposed to parapatric or sympatric processes following disruptive selection. Some cases where the taxonomy is difficult to unravel may, however, indicate parapatric speciation; examples belong to the genera Discula and Heterostoma (Helicidae) and Amphorella (Ferussaciidae). Most evidence relating to species composition in communities is compatible with a balance of random immigration and extinction, rather than selective interaction, allowing clusters of similar sympatric species to accumulate. However, this impression may indicate that test procedures are insufficiently sensitive to detect interactions, and detailed ecological studies are required. Questions about speciation and distribution would be clarified if dates of divergence were established.     

Are there adequate data to assess how well theories of rarity apply to marine invertebrates?

Understanding the biology of rare species is a very important part of conservation biology. Most of our current understanding of rarity has, however, come from studies of terrestrial plants, birds, mammals and some insects. Freshwater and marine habitats are underrepresented in published studies of rare species or conservation biology. We therefore have little knowledge about how well our understanding of what makes particular species rare and how rare species persist applies to marine invertebrates which form a major component of coastal biodiversity. In this review, I examine some theories about rarity with respect to intertidal and shallow subtidal invertebrates to identify whether there are adequate data to apply these theories to marine invertebrates and how well such theories apply. The general conclusions are that the lack of quantitative data on abundances, ranges, habitat-requirements, dispersal and connectedness among populations for marine invertebrates means that their status as rare species cannot really be assessed appropriately. It is also unlikely that, without extensive sampling programmes and considerable expense, adequate data could be obtained for these small, cryptic animals, which typically have very patchy, variable and unpredictable patterns of distribution and abundance. Intertidal and subtidal assemblages are diverse, including species with many different life-histories from many phyla, occupying the same suite of habitats. It is therefore suggested that future research on rare organisms in marine habitats should build upon the long and successful history of experimental marine studies to test specific hypotheses about processes influencing rarity in the field. Such studies would not only add a new dimension to our current understanding of rarity, but would also provide badly-needed data on the status of rare marine invertebrates. abundances, invertebrates, marine, range, rarity     

Predator impacts on stream benthic prey

The impact that predators have on benthic, macroinvertebrate prey density in streams is unclear. While some studies show a strong effect of predators on prey density, others show little or no effect. Two factors appear to influence the detection of predator impact on prey density in streams. First, many field studies have small sample sizes and thus might be unable to detect treatment effects. Second, streams contain two broad classes of predators, invertebrates and vertebrates, which might have different impacts on prey density for a variety of reasons, including availability of refuge for prey and prey emigration responses to the two types of predators. In addition, predatory vertebrates have more complex prey communities than predatory invertebrates; this complexity might reduce the impact that predatory vertebrates have on prey because of indirect effects. I conducted a meta-analysis on the results of field studies that manipulate predator density in enclosures to determine (1) if predators have a significant impact on benthic prey density in streams, (2) if the impacts that predatory invertebrates and vertebrates have differ, and (3) if predatory vertebrates have different impacts on predatory prey versus herbivorous prey. The results of the meta-analysis suggest that on average predators have a significant negative effect on prey density, predatory invertebrates have a significantly stronger impact than predatory vertebrates, and predatory vertebrates do not differ in their impact on predatory versus herbivorous invertebrate prey. Three methodological variables (mesh size of enclosures, size of enclosures, and experimental duration) were examined to determine if cross correlations exist that may explain the differences in impact between predatory invertebrates and vertebrates. No correlation exists between mesh size and predator impact. Over all predators, no correlation exists between experimental duration and predator impact; however, within predatory invertebrates a correlation does exist between these variables. Also, a correlation was found between enclosure size and predator impact. This correlation potentially explains the difference in impact between predatory invertebrates and predatory vertebrates. Results of the meta-analysis suggest two important areas for future research: (1) manipulate both types of predators within the same system, and (2) examine their impacts on the same spatial scale.     

The invertebrates of heather and heathland

WEBB, N. R., 1989. The invertebrates of heather and heathland. The southern heathlands of Great Britain have long been renowned amongst entomologists. The invertebrates fall into two groups: species which feed on heathland plants–about 40 in the case of Calluna–and a second group which depends on the particular physical conditions provided by heathland, such as hot dry sandy areas or the micro-topography of Sphagnum bogs. The ecology of representative examples will be described, and the effects of fragmentation and isolation of the heathlands on the distribution and abundance of invertebrates discussed.     

Citation Patterns of a Controversial and High-Impact Paper: Worm et al. (2006) “Impacts of Biodiversity Loss on Ocean Ecosystem Services”

Citation patterns were examined for Worm et al. 2006 (Science 314∶787–790), a high-impact paper that focused on relationships between marine biodiversity and ecosystem services. This paper sparked much controversy through its projection, highlighted in the press release, that all marine fisheries would be collapsed by 2048. Analysis of 664 citing papers revealed that only a small percentage (11%) referred to the 2048 projection, while 39% referred to fisheries collapse in general, and 40% to biodiversity and ecosystem services. The 2048 projection was mentioned more often in papers published soon after the original paper, in low-impact journals, and in journals outside of fields that would be expected to focus on biodiversity. Citing papers also mentioned the 2048 projection more often if they had few authors (28% of single-author papers vs. 2% of papers with 10 or more authors). These factors suggest that the more knowledgeable the authors of citing papers were about the controversy over the 2048 projection, the less likely they were to refer to it. A noteworthy finding was that if the original authors were also involved in the citing papers, they rarely (1 of 55 papers, 2%) mentioned the 2048 projection. Thus the original authors have emphasized the broader concerns about biodiversity loss, rather than the 2048 projection, as the key result of their study.     

Cumulative consumption of the lake macrophyte Elodea by abundant generalist invertebrate herbivores

Previous investigations have shown that macrophyte biomass can be substantially reduced by invertebrate herbivores but have not provided evidence for the links between the magnitude of the observed damage and the densities of herbivores. The results of this study support the hypothesis that the abundant occurrence of the epiphytic generalist herbivores may result in their cumulative consumption which, in turn, can be regarded as the mechanism responsible for often observed relatively high level of herbivory on freshwater macrophytes. The percentage of Elodea sp. biomass consumed by invertebrates was estimated for six European lakes, based on analysis of gut contents, daily rations and the density of epiphytic herbivores. Although the daily ration of these invertebrates when feeding upon Elodea averaged only 14.6% of their dry mass, their biomass was relatively high (from 0.163 to 1.161 g DW per 100 g DW plant). The estimated percentage of Elodea biomass consumed during one summer month by epiphytic invertebrates ranged from 0.5 to 5.9%. These values, after extrapolating to the whole growing season would mean that the biomass of Elodea lost to herbivory was between about 2 and 23%, an estimate which are within the range of consumption reported by other authors.     

What would have happened if Darwin had known Mendel (or Mendel's work)?

The question posed by the title is usually answered by saying that the "synthesis" between the theory of evolution by natural selection and classical genetics, which took place in 1930s-40s, would have taken place much earlier if Darwin had been aware of Mendel and his work. What is more, it nearly happened: it would have been enough if Darwin had cut the pages of the offprint of Mendel's work that was in his library and read them! Or, if Mendel had come across Darwin in London or paid him a visit at his house in the outskirts! (on occasion of Mendel's trip in 1862 to that city). The aim of the present paper is to provide elements for quite a different answer, based on further historical evidence, especially on Mendel's works, some of which mention Darwins's studies.     

The influence of invasive earthworms on indigenous fauna in ecosystems previously uninhabited by earthworms

Recent studies on earthworm invasion of North American soils report dramatic changes in soil structure, nutrient dynamics and plant communities in ecosystems historically free of earthworms. However, the direct and indirect impacts of earthworm invasions on animals have been largely ignored. This paper summarizes the current knowledge on the impact of earthworm invasion on other soil fauna, vertebrates as well as invertebrates.Earthworm invasions can have positive effects on the abundance of other soil invertebrates, but such effects are often small, transient, and restricted to habitats with harsh climates or a long history of earthworm co-occurrence with other soil invertebrates. Middens and burrows can increase soil heterogeneity and create microhabitats with a larger pore size, high microbial biomass, and microclimates that are attractive to micro- and mesofauna. Under harsh climatic conditions, the aggregates formed by earthworms may increase the stability of soil microclimates. Positive effects can also be seen when comminution and mucus secretion increase the palatability of unpalatable organic material for microorganisms which are the main food of most micro- and mesofaunal groups. For larger invertebrates or small vertebrates, invasive earthworms may become important prey, with the potential to increase resource availability. In the longer-term, the activity of invading earthworms can have a strong negative impact on indigenous faunal groups across multiple trophic levels. Evidence from field and laboratory studies indicates that the restructuring of soil layers, particularly the loss of organic horizons, physical disturbance to the soil, alteration of understory vegetation, and direct competition for food resources, lead directly and indirectly to significant declines in the abundance of soil micro- and mesofauna. Though studies of invasive earthworm impacts on the abundance of larger invertebrates or vertebrates are generally lacking, recent evidence suggests that reduced abundance of small soil fauna and alteration of soil microclimates may be contributing to declines in vertebrate fauna such as terrestrial salamanders. Preliminary evidence also suggests the potential for earthworm invasions to interact with other factors such as soil pollution, to negatively affect vertebrate populations.     

Sample Size in the Study of Behaviour

The choice of an appropriate sample size for a study is a notoriously neglected topic in behavioural research, even though it is of utmost importance and the rules of action are more than clear – or are they? They may be clear if a formal power analysis is concerned. However, with the educated guesswork usually applied in behavioural studies there are various trade‐offs, and the degrees of freedom are extensive. An analysis of 119 original studies haphazardly chosen from five leading behavioural journals suggests that the selected sample size reflects an influence of constraints more often than a rational optimization process. As predicted, field work involves greater samples than studies conducted in captivity, and invertebrates are used in greater numbers than vertebrates when the approach is similar. However, it seems to be less important for determining the number of subjects if the study employs observational or experimental means. This is surprising because in contrast to mere observations, experiments allow to reduce random variation in the data, which is an essential precondition for economizing on sample size. By pointing to inconsistent patterns the intention of this article is to induce thought and discussion among behavioural researchers on this crucial issue, where apparently neither standard procedures are applied nor conventions have yet been established. This is an issue of concern for authors, referees and editors alike.     

Response of the foraging behaviour of red wood ants (Formica rufa group) to exclusion from trees

Abstract 1 Because of the large numbers within a colony and their aggressive nature, red wood ants (Formica rufa group) have a potential to greatly influence the cold‐temperate forest ecosystem. Wood ants are omnivorous and hunt in trees as well as on the forest floor. 2 A field experiment in a mixed forest in central Sweden was carried out to examine (i) the foraging behaviour of wood ants on the forest floor and (ii) the impact of increased numbers of wood ants on the soil fauna. The foraging behaviour of wood ants was manipulated by excluding the ants from their food resources in the tree canopy, with the intention to increase ant activity on the forest floor. To estimate this activity, the number of trees with foraging ants, the numbers of ants going to and from their nests and the prey carried by home‐running wood ants were determined during the summer period. Pitfall traps were placed in the soil to determine effects on mobile soil invertebrates. 3 When excluded from local trees, wood ants searched other trees further away from the nests rather than searching more intensively for prey on the forest floor. By contrast to the initial hypothesis, more soil‐living prey were caught by ants in the control plots than in the plots where the local trees were not accessible to the wood ants. The proportion of soil‐living to tree‐living prey tended to be greater in the control plots. 4 In the treated plots (no access to the trees), wood ants had a negative effect on the activity of Linyphiidae spiders. There was little effect of wood ants on other soil invertebrates. 5 This study suggests that the role of wood ants as top predators in the forest soil food‐web in central Sweden is limited.     

Do Scientific Advancements Lean on the Shoulders of Giants? A Bibliometric Investigation of the Ortega Hypothesis

Background

In contrast to Newton''s well-known aphorism that he had been able “to see further only by standing on the shoulders of giants,” one attributes to the Spanish philosopher Ortega y Gasset the hypothesis saying that top-level research cannot be successful without a mass of medium researchers on which the top rests comparable to an iceberg.

Methodology/Principal Findings

The Ortega hypothesis predicts that highly-cited papers and medium-cited (or lowly-cited) papers would equally refer to papers with a medium impact. The Newton hypothesis would be supported if the top-level research more frequently cites previously highly-cited work than that medium-level research cites highly-cited work. Our analysis is based on (i) all articles and proceedings papers which were published in 2003 in the life sciences, health sciences, physical sciences, and social sciences, and (ii) all articles and proceeding papers which were cited within these publications. The results show that highly-cited work in all scientific fields more frequently cites previously highly-cited papers than that medium-cited work cites highly-cited work.

Conclusions/Significance

We demonstrate that papers contributing to the scientific progress in a field lean to a larger extent on previously important contributions than papers contributing little. These findings support the Newton hypothesis and call into question the Ortega hypothesis (given our usage of citation counts as a proxy for impact).     

Biochemical Screening Programme in General Practice: A Clinical Follow-up

Follow-up studies of findings obtained during a short programme of biochemical screening conducted on 1,041 patients attending their general practitioners in January 1967 showed that this yielded 64 results that led to a change in diagnosis or method of treatment. These results were obtained in 57 patients (5·5% of patients screened), whereas only 15 abnormal results would have been revealed on 14 of the 1,041 patients if the tests performed had been restricted to those requested on the basis of clinical features. Hence a screening programme can make an important contribution to the recognition of otherwise unsuspected disease.     

Genetic research with nonhuman primates: serving the needs of mankind Symposium summary and future prospects

The wide array of papers delivered at this symposium, ranging from population genetics to molecular genetics, is convincing evidence that genetic research with nonhuman primates is in full bloom. In fact, progress has been quite remarkable considering that a significant number of pedigreed colonies of nonhuman primates have been available for less than 25 years, which is hardly enough time to raise 3 generations of chimpanzees, 5 generations of baboons or 6 generations of rhesus monkeys. Were it not for these pedigreed colonies, we would not have been privileged to have this assemblage of papers on behavior, social structure, predisposition to disease and management of breeding colonies. It is indeed exciting that preliminary evidence has been obtained for major genes that play a role in susceptibility to dyslipoproteinemias in baboons, and that monoclonal antibodies and DNA markers are helping us to understand cholesterol metabolism. And thanks to computers, we can now rank animals in a colony in terms of their useful genotypes as well as their productivity. One can not help but be impressed with the commonality of humans and nonhuman primates at the structural and functional levels. For example, the major histocompatibility systems and the maternal-fetal relationships are very similar. We heard that this similarity is even more striking at the chromosomal, biochemical and DNA levels. A provocative question yet to be answered is, “what accounts for the obvious differences between humans and nonhuman primates in view of these incredible similarities?” In light of these advances, this symposium was at the cutting edge of primate genetics and the papers published in this issue of Genetica are certain to be hallmarks in the literature.     

Exposure of seawalls to waves within an urban estuary: effects on intertidal assemblages

Abstract Despite being largely protected from sea swell by headlands, shores within Sydney Harbour, New South Wales, Australia are subjected to considerable wave action from wind waves and the numerous recreational and commercial boats and ships using the waterways. The aim of this study was to test whether assemblages on artificial shores, that is, seawalls, either exposed to or sheltered from waves would show similar patterns to those published for natural shores exposed to or sheltered from sea swell. Specifically, the hypotheses were tested that sheltered seawalls would have greater cover of algae, whereas exposed seawalls would have greater cover of sessile invertebrates and greater abundance of mobile invertebrates. It was found that encrusting algae had greater cover on sheltered seawalls, whereas cover of turfing algae was greater on exposed walls. Sessile filter‐feeders generally had greater cover on exposed seawalls, although a dominant space occupier, the oyster Saccostrea glomerata, showed either no difference, or greater cover on sheltered seawalls among different locations. The pattern for the dominant grazer on seawalls, the pulmonate limpet Siphonaria denticulata showed the predicted pattern low on the shore, but the opposite pattern at mid‐tidal levels. Despite some inconsistencies the results were similar to those predicted from studies on natural shores, showing that assemblages on urban structures respond to wave action in a way that is predictable from studies on natural shores. Experiments were carried out where assemblages were transplanted to sites with differing exposure to waves to determine whether differences in recruitment or post‐recruitment mortality were responsible for patterns of difference. We found that some sessile invertebrates did not survive when transplanted to sheltered seawalls, suggesting that difference in survival of organisms was responsible for observed patterns. This was not, however, found when the experiment was repeated at other locations. It is likely that processes affecting the assemblages are temporally and spatially very variable, or that more than one process interacts to cause observed patterns. Identifying such complexity requires rigorously structured sampling designs and appropriate manipulative experiments.