Can taxonomic distinctness assess anthropogenic impacts in inland waters? A case study from a Mediterranean river basin

1. It is increasingly recognised that adequate measures of biodiversity should include information on the ‘relatedness’ of species within ecological assemblages, or the phylogenetic levels at which diversity is expressed. Taxonomic distinctness measures provide a series of indices to achieve this, which are independent of sample size. Taxonomic distinctness has been employed widely in marine systems, where it has been suggested that this index can provide a reliable measure of anthropogenic impact. 2. We tested the behaviour of three related taxonomic distinctiveness indices (Average Taxonomic Distinctness, Δ⁺; Variation in Taxonomic Distinctness, Λ⁺; and Total Taxonomic Distinctness, sΔ⁺) in relation to putative levels of anthropogenic impact in inland waters and their potential utility in environmental monitoring, using an extensive data set for aquatic beetles from the south‐east of the Iberian Peninsula. 3. Taxonomic distinctness measures were not able to identify human disturbance effects and there were no clear relationships between these new biodiversity measures and the disturbance level recorded at individual localities. Furthermore, the taxonomic distinctness measures used were apparently less sensitive to the effects of anthropogenic impact than other diversity metrics, such as species richness and rarity. 4. We conclude that taxonomic distinctness indices may not always perform as well as other metrics in the assessment of environmental quality. In addition, taxonomic distinctness measure should be interpreted with caution, as their performance and ability to detect anthropogenic disturbance may depend on the phylogenetic structure of sampled taxa within a region, and their evolutionary and ecological history.     

On the integrated frameworks of species concepts: Mayden’s hierarchy of species concepts and de Queiroz’s unified concept of species

Richard L. Mayden and Kevin de Queiroz have devised and developed ‘a hierarchy of species concepts’ and ‘a unified species concept’, respectively. Although their integrated frameworks of species concepts are rather different as to how to integrate the diverse modern concepts of species, the end result is that they are likely to agree on species recognition in nature, because they virtually share the same major components (i.e. evolutionary or lineage concept of species; same way of delimiting species), and have the same important consequences. Both the hierarchical and unified frameworks, however, are interpreted to have shortcoming regarding the way of integrating the modern species concepts. I reformulate these ideas into a framework of species concepts as follows: It treats the idea of species as population‐level evolutionary lineages (sensu Wiley 1978 ) as the concept for species category, and it adopts the contingent biological properties of species (e.g. internal reproductive isolation, diagnosability, monophyly) as operational criteria in delimiting species. I also suggest that existing and revised versions of the integrated framework of species concepts all are not new species concepts, but versions of the evolutionary species concept, because they treat the evolutionary (or lineage) species concept as the concept for species category.     

The influence of spatial scale on the congruence of classifications circumscribing morphological units of biodiversity

Aim The ‘taxonomic impediment’ has led to a growing trend in ecology and conservation biology to use operational surrogates for species within the context of a particular research project. Because such ‘parataxonomic’ classifications are typically spatially limited in scope, we examined the influence of increasing spatial scale on the congruence of two such approaches with a more traditional taxonomic classification. Location Sturt National Park, north‐western New South Wales, Australia. Methods Specimens of two ant genera, Camponotus and Rhytidoponera, were classified by three independent methods. The ‘parataxonomic’ classification assigned specimens to morphospecies without specialist taxonomic expertise; the ‘taxonomic’ classification assigned specimens to either described species or, where this was not possible, to operational taxonomic units (OTUs) using specialist taxonomic expertise; the ‘phenetic’ classification assigned specimens to putative species using a K‐means partitioning algorithm on basic morphometric data. Specimens of each genus were pooled into ‘assemblages’, which were defined at multiple spatial scales using a nested sampling design. Congruence in the interspecimen relationships of the different classifications was tested for each assemblage using pair‐wise Mantel correlations. Results Classification congruence tended to decrease with increasing spatial scale. There were, however, clear differences between the genera. Parataxonomic–taxonomic congruence was consistently greater for Camponotus, while phenetic–taxonomic congruence showed the opposite pattern. Conclusions Observed patterns in classification congruence are attributed to two principal causes: (i) within‐species morphological variation, including ecotypic variation in Rhytidoponera and caste polymorphism in Camponotus; and (ii) a limit to the morphological similarity of potentially competing species at small spatial scales. Regardless of cause, the decline in agreement as the spatial scale of observation is increased has important implications for the measurement of biodiversity, particularly when comparing samples over regional, continental, and global scales.     

Interspecific pairwise relationships among body size, clutch size and latitude: deconstructing a macroecological triangle in birds

Aim Ecogeographical ‘rules’, large‐scale patterns in ecological variables across geographical space, can provide important insights into the mechanisms of evolution and ecological assembly. However, interactions between rules could obscure both the observation of large‐scale patterns and their interpretation. Here, we examine a system of three variables interrelated by ecogeographical rules – the latitudinal increase in body size within closely related homeotherms (Bergmann’s rule), the negative allometry of clutch size (Calder’s rule) and the latitudinal increase in clutch size (Lack’s rule) – in a global dataset of birds. Location Global. Methods We used linear regressions and meta‐analysis techniques to quantify the three rules across clades and through the taxonomic hierarchy. Path analysis was used to quantify interactions between rules at multiple taxonomic levels, as a function of both phylogenetic inheritance of traits and indirect feedbacks between the three rules. Independent contrasts analyses were performed on four clades with available phylogenies, and the taxonomic partitioning of variation in each trait was quantified. Results Standardizing across all clades, Lack’s and Bergmann’s rules were supported at all taxonomic levels, with Calder’s rule being supported at the order level. Lack’s rule was consistently stronger and more often detected than the other two rules. Path analysis showed that the indirect effects often outweighed the direct effects of Calder’s rule at the genus level and Bergmann’s rule at the order level. Strong interactions between Calder’s and Bergmann’s rules led to a trade‐off between the rules depending on taxonomic resolution. Main conclusions We found strong interactions between Bergmann’s, Lack’s and Calder’s rules in birds, and these interactions varied in strength and direction over the taxonomic hierarchy and among avian clades. Ecogeographical rules may be masked by feedbacks from other, correlated variables, even when the underlying selective mechanism is operating. The apparently conflicting pairwise relationships among clutch size, body size and latitude illustrate the difficulty of interpreting individual pairwise correlations without recognition of interdependence with other variables.     

Body‐size distribution and biogeographical patterns in non‐marine ostracods (Crustacea: Ostracoda)

The idea that free‐living minute organisms have ubiquitous distributions has been recently revitalized, causing significant controversy. The ubiquitous model predicts that a threshold where ubiquity leaves room to biogeography might exist somewhere along the animal body‐size range. In the present study, such a prediction is tested by analysing body‐size frequency distribution, species distribution, and local‐to‐global species ratio at the scale of biogeographical realms in cypridoidean non‐marine ostracods, a group with a body‐size range in the ubiquity–biogeography (U‐B) boundary. Data were gathered for all described extant cypridoidean ostracod species (N = 1761), with body‐size recorded for 1134 of them. Although local‐to‐global species ratios show significant over‐dispersal of small‐body ostracods for the Palaearctic and the Australasian regions, there are explanations alternative to the ‘Everything is Everywhere’ model that can account for such a result. Indicators of taxonomic structure do not support the hypothesis of a random distribution of cypridoidean species among realms. Nevertheless, the strong biogeography signal occurring at a large scale vanishes at the local scale (country‐level within the Palaearctic), and suggests wide dispersion within biogeographical realms. Additional factors, including inconsistent taxonomic criteria for species recognition, uneven sampling effort, and an excess of ‘single‐report’ occurrences, have been identified too as potential distorters of the observed patterns. Taxonomic harmonization, open databases of biogeographical data, and better ecological information are suggested as critical goals that need to be achieved for further understanding of ostracod global distribution patterns. © 2013 The Linnean Society of London, Biological Journal of the Linnean Society, 2013, 109 , 409–423.     

Distinct invasion strategies operating within a natural annual plant system

Alien plant species are known to have a wide range of impacts on recipient communities, from resident species’ exclusions to coexistence with resident species. It remains unclear; however, if this variety of impacts is due to different invader strategies, features of recipient communities or both. To test this, we examined multiple plant invasions of a single ecosystem in southwestern Australia. We used extensive community data to calculate pairwise segregation between target alien species and many co‐occurring species. We related segregation to species’ positions along community trait hierarchies and identified at least two distinct invasion strategies: ‘exploiters’ which occupy high positions along key trait hierarchies and reduce local native species diversity (particularly in nutrient‐enriched situations), and ‘coexisters’ who occupy intermediate trait positions and have no discernable impact on native diversity. We conclude that trait hierarchies, linked to measures of competition, can provide valuable insights about the processes driving different invasion outcomes.     

A Constant of temporal structure in the human hierarchy and other systems

The levels that compose biological hierarchies each have their own energetic, spatial and temporal structure. Indeed, it is the discontinuity in energy relationships between levels, as well as the similarity of sub-systems that support them, that permits levels to be defined. In this paper, the temporal structure of living hierarchies, in particular that pertaining to Human society, is examined. Consideration is given to the period defining the lifespan of entities at each level and to a periodic event considered fundamental to the maintenance of that level. The ratio between the duration of these two periods is found to be approximately 2.5 × 10⁴. A similar relationship is found when lower, non-living levels of molecules and atoms are considered. This suggests that there is a constant factor of amplification between analogous periodic events at successive levels of the Human hierarchy.     

Hormonal Correlates of Social Rank in an Asocial Species, the Common Brushtail Possum (Trichosurus vulpecula)

Dominance hierarchies play an important role in access to mates or resources in many species. Rank is sometimes correlated with circulating testosterone levels or morphological traits such as body weight. The relationship of glucocorticoid secretion and rank, however, is less clear. In this study, we investigated the relationship of male rank to body weight, circulating testosterone and cortisol concentrations in captive possum triads (Trichosurus vulpecula). We carried out two experiments to examine hierarchy formation and the effects of castration of the dominant male during the non‐breeding season. A third experiment measured the effects of removal of the dominant male from a stable hierarchy during the breeding season. We found that dominant male rank was significantly correlated with higher circulating testosterone levels during periods of hierarchy formation and during the breeding season but not during periods of hierarchy stability in the non‐breeding season. Lack of correlation between plasma testosterone concentration and rank after male castration suggests that stable social rank is not dependent on hormone level and may be more dependent on behavioural traits. Any biocontrol measures that rely on manipulation of hormone levels may be unreliable when applied to unstable hierarchical situations, including the establishment of territories by subadult males, and the pre‐breeding season when circulating testosterone concentrations peak in males and a period of hierarchy establishment may occur.     

Freshwater fish introductions in mediterranean‐climate regions: are there commonalities in the conservation problem?

Aim To compare patterns and drivers of freshwater fish introductions across five climatically similar regions and evaluate similarities and differences in the non‐native species introduced. Location Five mediterranean‐climate regions: California (USA), central Chile, south‐western Australia, the Iberian peninsula (Spain and Portugal) and the south‐western Cape (South Africa). Methods Species presence–absence for native and non‐native fishes were collated across the regions, and patterns of faunal change were examined using univariate and multivariate statistical approaches. Taxonomic patterns in freshwater fish introductions were evaluated by comparing the number of species introduced by order to the numbers expected from binomial probabilities. Factors influencing multiple introductions of freshwater fish species in mediterranean regions were determined using generalized linear modelling. Results High levels of endemism (70–90%) were revealed for south‐western Cape, south‐western Australia and Chile. Despite their high rates of endemism, all regions currently have more non‐native species than endemic species. Taxonomic selection was found for five orders, although this was only significant for Salmoniformes across regions. The average increase in regional compositional similarity of fish faunas resulting from non‐native fish introductions was 8.0%. Important factors predicting multiple introductions of a species include previous introduction success and mean latitude of its distribution Main conclusions The mediterranean‐climate regions of the world, separated by vast distances, originally had a few fish species in common but are now more similar, owing to species introductions, illustrating the extent and importance of taxonomic homogenization. Introductions are largely driven by taxonomically biased human interests in recreational fisheries, aquaculture and ornamental pet species.     

The problem of peers in Vietnamese interaction

In Vietnamese, address (second‐person reference) is typically accomplished by the use of a kin term regardless of whether the talk's recipient is a genealogical relative or not. All Vietnamese kin terms encode a specification of either relative age or relative generation of participants, and there are no reciprocal terms akin to English ‘brother’ or ‘sister’; rather, a speaker must select between terms such as ‘older brother’ (anh) or ‘younger sibling’ (em). Since generation is normatively associated with a difference in age, the result is a ubiquitous indexing of age and status hierarchies in all acts of address. This results in a problem for peers. How, in such a system, should they address one another (and also self‐refer)? In this article, we describe the various practices that speakers use to subvert the system and thus avoid indexing differences of age or station. Specifically, we describe four practices: (1) the use of true pronouns in address and self‐reference; (2) the use of proper names in address and self‐reference; (3) the use of kin terms in address and pronouns in self‐reference; and (4) the ironic use of kin terms in address. We conclude that the Vietnamese system well illustrates what is likely a universal tension between hierarchy and equality in acts of address and self‐reference, by showing how speakers deconstruct the vector of age and indicate that they consider one another peers. We further suggest that although the literature in this area has focused on the ways in which languages convey differences of status and rank, social order is built as much upon relations of parity and sameness – on identification of the other as neither higher nor lower than me – as it is upon relations of hierarchy.     

Evolution of heteroneuran Lepidoptera (Insecta) and the utility of dopa decarboxylase for Cretaceous-age phylogenetics

This study tests the utility of the nuclear gene encoding dopa decarboxylase (DDC) for recovering Cretaceous‐age divergences within the lepidopteran clade Heteroneura, which contains 98% of lepidopteran species. A 709‐bp fragment of DDC has been sequenced in 32 species, including representatives of all major lineages of Heteroneura plus outgroups from more basal lepidopteran groups and the related order Trichoptera. Pairwise divergences across the first and second codon positions and amino acids increase with depth throughout the taxonomic hierarchy, indicating that non‐synonymous substitutions are not fully saturated; whereas, divergences across the third codon position level off at the family to superfamily level. Inclusion of non‐neolepidopteran outgroups results in phylogeny estimates that contradict well established groups, almost surely due to sparse taxon sampling and high character divergence. When these taxa and an equivalently divergent basal ditrysian are excluded, DDC trees show nearly complete recovery of ten uncontroversial basal heteroneuran ‘test clades’ of family rank and higher, about half with strong bootstrap support. Thus, DDC clearly carries phylogenetic signal at these levels. Bootstrap support for resolution of the controversial relationships among the five main heteroneuran groups (four monotrysian superfamilies plus Ditrysia) is individually low, but two of three previous hypotheses were statistically rejected overall by DDC. DDC trees within the primitive heteroneuran superfamily Incurvarioidea, though modestly supported, closely resemble a previous morphological hypothesis, while removing the requirement for reversal in a possible ‘key adaptation’, the larval case. Taxon overlap with a previous mtDNA study of Prodoxidae (Incurvarioidea), which includes much‐ studied mutualist pollinators, permits a comparison of substitution rates with the conservative mitochondrial COI+COII region, as well as combined‐data re‐examination of generic reltionships. Non‐synonymous substitution is about 25% slower in DDC than in COI+COII, though synonymous substitution is faster. With additional taxon sampling, and in combination with other genes, DDC promises to be a powerful tool for reconstructing among‐superfamily relationships within Lepidoptera and probably other insect groups.     

A Novel Method of Assessing Dominance Hierarchies Shows Nuance,Linearity and Stability in the Dinosaur Ant Dinoponera quadriceps

Many social species with relatively simple societies have dominance hierarchies of individuals, with dominant individuals achieving fitness and subordinate individuals either queuing to obtain fitness or achieving only indirect fitness by helping relatives. Assessing the dominance hierarchy in a social group is generally based upon observing dyadic interactions as and when they occur spontaneously within the whole‐group setting. However, this method can be very time‐consuming because many dyads interact only very rarely, necessitating either extremely long observation periods or many dyadic relationships being unresolved. Here, we report an alternative method using the queenless dinosaur ant Dinoponera quadriceps, which lives in colonies containing tens of individuals. We removed all individuals from their nest and observed the dominance behaviours expressed in isolated dyadic interactions for every pairwise combination of individuals. Individuals showed a classic dominance behaviour in this setting, and the rapid nature of the assay allowed us to observe every dyadic relationship on a weekly basis over 4 weeks. The dominance hierarchies based on these isolated dyadic interactions correlated well with those produced by the conventional method of colony observations. They showed the hierarchies to be highly linear and stable, and also revealed that dominance relationships may extend further down the hierarchy than previously thought. Although highly manipulative, the isolated dyadic interaction method works well and will likely make more feasible the study of other social species in which pairs of individuals can be isolated together.     

Latitude, elevation and body mass variation in Andean passerine birds

• 1 Relationships between body mass and latitude, and body mass and elevation are examined in the assemblage of Andean passerine birds.
• 2 Across species, body mass is positively correlated with the mid‐point of the species elevational distribution, but there is no significant relationship between body mass and latitudinal range mid‐point.
• 3 When the assemblage is separated into Andean endemic and non‐endemic species, the former group shows a significant positive relationship between body mass and elevation, and the latter a significant positive relationship between body mass and latitude (‘Bergmann’s rule’). Andean endemic species exhibit Bergmann’s rule once elevation is controlled for using multiple regression.
• 4 These relationships are not a consequence of the phylogenetic non‐independence of species. All the effects shown are very weak, with latitude and elevation explaining only a few per cent of the variation in body mass. Relationships are strongest when phylogenetically controlled analyses are performed just within genera.
• 5 The implications of these results for the mechanistic understanding of Bergmann’s rule are discussed.

     

A critique of 'countryside biogeography' as a guide to research in human‐dominated landscapes

Proliferation of redundant terms in ecology and conservation slows progress and creates confusion. ‘Countryside biogeography’ has been promoted as a new framework for conservation in production landscapes, so may offer a replacement for other concepts used by landscape ecologists. We conducted a systematic review to assess whether the 'countryside biogeography' concept provides a distinctive framing for conservation in human‐dominated landscapes relative to existing concepts. We reviewed 147 papers referring to countryside biogeography and 81 papers that did not. These papers were divided into categories representing three levels of use of countryside biogeography concepts (strong, weak, cited only) and two categories that did not use countryside biogeography at all but used similar concepts including fragmentation and matrix. We revealed few distinctions among groups of papers. Countryside biogeography papers made more frequent use of the terms 'ecosystem services', 'intensification' and 'land sparing' compared with non‐countryside biogeography papers. Papers that did not refer to countryside biogeography sampled production areas (e.g. farms) less often, and this related to their focus on habitat specialist species for which patch‐matrix assumptions were reasonable. Countryside biogeography offers a conceptual wrapper rather than a distinctive framework for advancing research in human‐modified landscapes. This and similar wrappers such as ‘conservation biogeography’ and ‘agricultural biogeography’ risk creating confusion among new researchers, and can prevent clear communication about research. To improve communication, we recommend using the suite of well‐established terms already applied to conservation in human‐modified landscapes rather than through an interceding conceptual wrapper.     

An integrative approach to species delineation incorporating different species concepts: a case study of Limnadopsis (Branchiopoda: Spinicaudata)

The unambiguous delineation and identification of species remain central problems in systematic and taxonomic studies. Species delineation depends on the data utilized and the species concept applied. In recent years, morphology‐based species delineation has been complemented by DNA sequence data, leading to an integrative taxonomy. Such integrative approaches, however, are hampered by the partial incongruence of the various data types with certain species concepts. In this study, we delineated Australian Limnadopsis species employing one mitochondrial (cytochrome c oxidase subunit I, COI) and one nuclear (elongation factor 1α, EF1α) marker and a morphological character apparently part of the specific mate recognition complex, and therefore potentially indicative of reproductive isolation. By integrating the data over various species concepts (e.g. the ‘biological’, ‘Hennigian’, ‘recognition’, ‘phylogenetic’ and ‘evolutionary’ species concepts), the delineation of most species becomes straightforward and unambiguous. Conflicts are particularly interesting as they reveal different aspects of speciation considering the various species concepts. Our study emphasizes the benefits of a truly integrative approach to taxonomy. By combining molecular data with morphological characters indicative of reproductive isolation, it is possible to delineate species integrating not only different data types, but also different underlying species concepts. Overall, 11 Limnadopsis species could be delineated, including all eight currently recognized species, and three so far undescribed species. Most species were congruently delineated under all species concepts. A strict application of the evolutionary species concept, however, would have further split L. parvispinus into two species on the basis of the COI data. In addition, Limnadopsis tatei is consistently split into two sympatrically occurring species under all applied species concepts. © 2011 The Linnean Society of London, Biological Journal of the Linnean Society, 2011, 104 , 575–599.     

European Settlement and the Making and Unmaking of Aboriginal Identities

This paper explores variation and change in Aboriginal people's connections to places, and place‐related identity, as a function of their differential historical relationship to a town. Among Aboriginal people who have lived for some decades in camps around Katherine, Northern Territory, descendants of those who appear to have the most clearly discernable long‐term relationship with the area in the vicinity of the town do not relate to places, nor conceptualise them, in stereotypically ‘traditional’ terms. Their relationships to town and nearby places tend to be of an ideologically unelaborated, homely sort. Kinds of territorial relationships their antecedents can be shown to have had to the area have undergone dissolution. The paper seeks to develop discussion of such variation and the historical and sociological processes involved. The Katherine case brings the social and historical significance of ‘towns’ as sites of Aboriginal/non‐Aboriginal interrelationship into focus, and also requires a critical view of notions of ‘group’ that have tended to dominate recent public process and understanding in Australia.     

Empirical evidence for source–sink populations: a review on occurrence,assessments and implications

Assessing the role of local populations in a landscape context has become increasingly important in the fields of conservation biology and ecology. A growing number of studies attempt to determine the source–sink status of local populations. As the source–sink concept is commonly used for management decisions in nature conservation, accurate assessment approaches are crucial. Based on a systematic literature review of studies published between 2002 and 2013, we evaluated a priori predictions on methodological and biological factors that may influence the occurrence of source or sink populations. The review yielded 90 assessments from 73 publications that included qualitative and quantitative evidence for either source or sink population(s) for one or multiple species. Overall, sink populations tended to occur more often than source populations. Moreover, the occurrence of source or sink populations differed among taxonomic classes. Sinks were more often found than sources in mammals, while there was a non‐significant trend for the opposite to be true for amphibians. Univariate and multivariate analyses showed that the occurrence of sources was positively related to connectivity of local populations. Our review furthermore highlights that more than 25 years after Pulliam's widely cited publication on ‘sources, sinks, and population regulation’, in‐depth assessments of the source–sink status of populations based on combined consideration of demographic parameters such as fecundity, survival, emigration and immigration are still scarce. To increase our understanding of source–sink systems from ecological, evolutionary and conservation‐related perspectives, we recommend that forthcoming studies on source–sink dynamics should pay more attention to the study design (i.e. connectivity of study populations) and that the assessment of the source–sink status of local populations is based on λ values calculated from demographic rates.     

The multiple meanings of moongo: on the conceptual character of doorways and backbones in Kilimanjaro

By means of ‘connective analysis’, this article explores the multiple meanings of moongo among the Chagga‐speaking people of Rombo district, Kilimanjaro region, which resemble neglected meanings of the vernacular terms translated as ‘lineage’ elsewhere. These meanings were eclipsed by an analytical move that privileged ‘the political’ at the expense of other relations. By suspending the question of politics, it is shown how moongo is central to bridewealth exchanges and reproductive relationships, which provides new impetus to classic anthropological discussions of the house‐property complex. The result is to treat moongo as a concept in its own right, which enunciates and concerns how persons and houses are transformations of each other and effects of particular relationships.