Molecular genetic assessment of bipolarity in the anchovy genus Engraulis

To test three hypotheses accounting for bipolar distributions in Engraulis , seven of eight taxa (except E. eurystole ) were surveyed with allozymes (34 loci) and 521 bp of the mitochondrial DNA cytochrome b gene. Both allozymes and mtDNA sequences revealed deep separations between New World and Old World anchovies with a mean allozyme genetic distance D  = 1·26 and net mtDNA sequence divergence d  = 15%. These values reflected separations of 5 to 10 million years. Contrary to previous phylogenetic hypotheses, which place north‐east Pacific E. mordax and south‐east Pacific E. ringens as sister taxa, the south‐west Atlantic E. anchoita and E. ringens are most closely related to each other. The north‐east Pacific E. mordax is the closest lineage to the Old World Engraulis , a group of taxa showing low divergences typical of population‐level separations (mean D  = 0·06; mean d  = 0·87%). Bipolarities of sister taxa in the east Atlantic and west Pacific reflect recent dispersals. Bipolarities in the east Pacific and west Atlantic represent paraphyletic taxa in lineages isolated since the Miocene. None of the bipolarities can be attributed to tectonic separations or competitive displacements from the tropics, but the latter situation should be re‐evaluated with comparisons to tropical anchovies of the New World.     

Multi-scale determinants of dung beetle assemblage structure across abiotic gradients of the Kalahari–Nama Karoo ecotone, South Africa

Aim Changing conditions across spatial gradients are primary determinants of biotic regions, local habitats, and distributional edges. We investigate how a climatic gradient and edaphic mosaic interact as multi‐scale drivers of spatial patterns in scarabaeine dung beetles. The patterns are tested for congruency with ecoregion and floral boundaries over the same gradient, as responses to physical factors often differ among higher taxa. Location Southern Africa and the Nama Karoo–Kalahari ecotone, Northern Cape, South Africa. Methods Data consisted of the climatic distributions of 104 species and their abundances at 223 sites in two ecoregions/floral biomes, four bioregions, and 13 vegetation units. Factor analyses determined the biogeographical composition of the species, and regional‐ to local‐scale patterns in species abundance structure. Hierarchical analysis of oblique factors determined the proportional contribution of spatial variance to patterns. One‐way anova was used to test for significant separation of patterns along factor axes. Stepwise multiple regression was used to determine correlations of five physical attributes with species richness, Shannon‐Wiener diversity, and factor loadings for the study sites. Results Four biogeographical influences overlap in the study region, although rank contribution declines from south‐west arid through north‐east savanna to widespread and south‐east highland taxa. Species abundance structure comprises five subregional patterns, two centred to the north‐east (Kalahari, Isolated Kalahari Dune) dominated by Kalahari influence, and three to the south‐west (Nama Karoo subdivisions: Bushmanland, ‘Upper’, ‘Stony Prieska’) dominated by south‐west arid influence. Kalahari deep sands are characterized especially by a warmer, moister climate, whereas the Nama Karoo mosaic of deep or stony soils is characterized especially by north‐west aridity (Bushmanland), south‐east cooler temperatures (‘Upper’), or excessively stony soils (‘Stony Prieska’). Four of the subregional patterns each comprised three localized patterns related primarily to relative stoniness, edge effects from geographical position, or incidence of rainfall. Species richness and diversity declined with decreasing rainfall and increasing stoniness. Main conclusions Climatic and edaphic factors are important multi‐scale determinants of spatial patterns in dung beetle assemblage structure, with edaphic factors becoming more important at local spatial scales. The patterns are roughly congruent with the Kalahari Savanna–Nama Karoo ecotone at the floral biome or ecoregion scale, but show limited coincidence with finer‐scale floral classification.     

Fish larvae assemblages in the Gulf of California

The distributional diversity and assemblages of fish larvae in the Gulf of California indicated two main seasonal stages and two transitional periods: in winter, the tropical water mass is confined to the south‐east portion of the mouth of the Gulf and larval fish assemblages are dominated by subtropical and temperate‐subarctic species; in summer; tropical water invades the Gulf and assemblages are dominated by tropical species. Both seasonal stages are separated by transitional periods coinciding with strong latitudinal temperature gradients. During the autumn and spring transitional periods, the Gulf of California splits into three regions: a northern region where temperate and subarctic species spawn from autumn to spring, a southern region dominated by tropical and subtropical species year round and a central region where tropical and temperate assemblages merge. Seasonal changes in the location of the regions, as well as the borders between them, show expansion and contraction of the northern and southern faunas related to the general oceanic circulation patterns during the year.     

Factors structuring reproductive habitat suitability of Engraulis encrasicolus in the south coast of Sicily

Egg and larval abundance, obtained from annual summer cruises carried out in the Strait of Sicily during 6 years (1997 to 2002), was used to identify the spawning and retention areas of the anchovy Engraulis encrasicolus . Larval amino acid composition was used to analyse the nutritional condition of the larvae collected during the 2002 survey. As the anchovy spawns along the south Sicilian coast, but mainly in the north‐west and middle parts of the coast, the higher number and larger size larvae in the south‐east end of the Sicilian coast indicated that larvae were transported by the main branch of the Atlantic‐Ionian Stream and retained in the south‐east end of the Sicilian coast (Cape Passero). This retention process, however, did not always favour the nutritional condition of the larvae, because the larvae were not transported to an area with a higher primary production or with a higher stability. In 2002 larval amino acid concentration was higher in the spawning areas than in those areas where the larvae were transported to, indicating a lower nutritional condition of the larvae in the nursery areas. The lack of enrichment and concentration processes, and low primary production in this area which limited body growth rate may explain the low locally reproducing anchovy population in the south coast of Sicily.     

Edaphic and climatic history has driven current dung beetle species pool and assemblage structure across a transition zone in central South Africa

We investigate biogeographical, regional and sub‐regional‐scale responses of scarabaeine dung beetles to late Cenozoic changes in edaphic and climatic character that created a Savanna/Karoo transition zone in the Northern Cape, South Africa. Across a 50 200 km² study area, the Northern Cape species pool comprised six biogeographical groups defined from distribution across southern Africa. These species groups contributed in different proportions to five regional assemblages defined from structural differences across the transition zone. Towards transition zone peripheries, regional assemblage structure was more strongly correlated to sandiness dating from Miocene to Pliocene deposition (Kalahari), aridity dating from Pliocene to Pleistocene climatic change (Bushmanland Karoo), or cooler temperatures dating from Miocene to Pliocene uplift (Upper Karoo). Correlates of sub‐regional assemblages trended to intensification of dominant drivers towards regional peripheries. Drivers of central transition zone, regional assemblages (‘Gariep Karoo’, ‘Gariep Stony Karoo’) showed no dominance. Biogeographically, endemism dominates the Northern Cape transition zone: south‐west arid groups in Nama Karoo regions; Kalahari plus north‐east savanna groups in the Kalahari. Regionally, transition drives assemblage structure: unique variance, 60% in the Kalahari, 21–30% in four Nama Karoo regions; shared variance (overlap), 25–65% between Kalahari and warmer Karoo regions, 11–71% between mainly cooler Karoo regions.     

Species turnover, community boundaries and biogeographical composition of dung beetle assemblages across an altitudinal gradient in South Africa

Aim To identify biogeographical boundaries which are obscured by faunal overlap and habitat modification. Location KwaZulu-Natal in south-east, South Africa beyond the southern tip of the Moçambique Coastal Plain. Methods Species abundance data for dung beetles (Scarabaeidae: Scarabaeinae) were collected at six levels from the coastal escarpment (30°16′S – 500 m) to the top of the nearby Drakensberg (29°35′S – 2850 m). Cross-altitudinal boundaries were identified using clustering techniques, beta-diversity indices, and range edge analysis. Biogeographical data for the species were drawn from an extensive reference collection and used to classify the biogeographical affinities of the assemblages. Results Three discrete communities are defined (<10% similarity) from species abundance distributions. These communities occur in coastal forest (500 m), coastal to highveld grassland (500–1500 m), and montane grassland (1900–2850 m). Two of these communities are biogeographically homogeneous comprising >89% east coast endemics (coastal forest) or >84% South African montane endemics (montane grassland) in terms of abundance. The third community in coastal to highveld grassland is biogeographically more heterogeneous. Predominant biota of this community comprise both South African highveld endemics and elements with distributions extending into the tropics. At highveld levels (1500 m), there are proportionately more highveld endemics whereas at lowland levels (500 m), there are proportionately more tropical elements. At 1000 m, there was a change in the balance between these two groups across an anthropogenic gradient due to a decline in the proportion of endemics in favour of temperate/tropical generalists. This gradient from a natural grassland fragment to improved pastures of Kikuyu grass also parallels a decline in species richness and abundance. Species turnover analyses showed three different cross-altitudinal patterns. Range-edge analysis showed a trimodal pattern of species turnover (peaks in forest and the Drakensberg foothills as in the community analysis but also at 1000 m). Five beta-diversity indices showed either a bimodal pattern of turnover (forest/grassland and foothills/middle Drakensberg slopes) or a trimodal turnover pattern (forest/grassland, highveld/Drakensberg foothills, Drakensberg peaks). Main conclusions Clear altitudinal zonation is revealed by community and biogeographical analysis but one natural biogeographical boundary may be obscured by the process of habitat modification. This boundary at 1000 m is revealed by range-edge analysis and is supported by findings for plant communities. Beta-diversity, species turnover patterns diverged slightly from those suggested by the community and range-edge analyses.     

Use of parasite and genetic markers in delineating populations of winter flounder from the central and south‐west Scotian Shelf and north‐east Gulf of Maine

Discriminant function analyses of infection parameters of parasitic helminths revealed that abundances of seven helminth species contributed significantly to the delineation of four host populations of winter flounder Pleuronectes americanus from the central and south‐west Scotian Shelf and the north‐east Gulf of Maine (NAFO subdivision 4WX‐5Z). These were adult digeneans, Derogenes varicus , Genolinea laticauda , Steganoderma formosum and Steringophorus furciger , metacercariae of the digenean, Stephanostomum baccatum , and larval nematodes, Anisakis simplex and Hysterothylacium aduncum . The correct classification rate was 84% overall, with Georges Bank (5Z) and Sable Island Bank (4W) winter flounder being the most accurately classified samples at 98 and 88%, respectively. Winter flounder from south‐west Nova Scotia (4X), an inshore sample from St Marys Bay and offshore fish from Browns Bank, had the lowest rates of correct classification (76 and 71%, respectively) due, primarily, to cross‐misclassification between the two samples. Winter pairwise comparisons of four microsatellite markers identified significant genetic differences between all populations sampled with the Georges Bank population being the most genetically distinct overall, and St Marys Bay and Browns Bank fish being the least dissimilar.     

Reproductive biology of gag in the southern Gulf of Mexico

Aspects of the reproductive biology of gag Mycteroperca microlepis in the southern Gulf of Mexico were studied by following seasonal variations in the gonado‐somatic index and through histological examination of gonads. Gag were collected from inshore and offshore waters of the Campeche Bank, Yucatan, Mexico, between April 1996 and December 2001. This species is a protogynous hermaphrodite, and appeared to be depth‐size distributed. The smallest gag (9–49 cm L _F) collected were all juvenile females, and were caught in inshore waters (1–10 m depth), while the largest (49–116 cm L _F), mainly adult females, males and transitionals, were captured in offshore waters (33–167 m depth). Overall the offshore male to female ratio was female‐biased (1 : 3·3) and differed significantly from unity. The species spawns at depths of c . 50–53 m, from early winter to mid‐spring, with peak spawning activity occurring between January and March. Fifty per cent of females reached first maturity at 72·1 cm L _F. At 103 cm L _F, 50% of sampled females had changed into males. Gag can be considered a monandric species, and sexual transition for this grouper seemed to occur in fish distributed within a narrow size range (85–111 cm L _F). The results are compared with those of other authors for gag stocks from the south‐east Atlantic coast of the U.S.A. and the north‐east Gulf of Mexico.     

Rainfall and the population dynamics of elephant dung‐piles in the forests of southern Ghana

Decaying dung‐piles were observed at three sites in the lowland forests of southern Ghana. Time to disappearance was inversely related to rainfall in the month of deposition. The monthly survival of each age‐class decreased with age and was inversely proportional to rainfall in the month of deposition. A simulation revealed that if elephant numbers and defaecation rates are constant, then dung density in a given month will be governed by rainfall in the two preceding months. Changes in annual rainfall and its monthly distribution in southern Ghana mean that dung‐pile densities will vary from one month to the next, and between the same months in different years, even if elephant numbers are constant. Thus dung counters must take rainfall into account. A new method of censusing elephants in Ghana is presented, and suggestions are made for improving elephant counts in central African forests.     

Promiscuous spawning behaviour of the tropical herring Spratelloides gracilis

Spawning behaviour of the blue sprat Spratelloides gracilis was observed at shallow reefs of Kuchierabu‐jima Island, southern Japan. The fish carried out promiscuous spawning behaviour on substrata covered with algal mats mainly in the intertidal region of a shallow inlet. The spawning events occurred only at predawn (20–50 min before sunrise) and daily for c . 25 days from mid‐June to mid‐July.     

Systematics of the dung beetle tribe Sisyphini Mulsant (Scarabaeidae: Scarabaeinae) inferred from a molecular phylogeny and biogeography of southern African species

The tribe Sisyphini Mulsant was recently redefined following the transfer of the endemic southern African genus Epirinus Dejean from the polyphyletic tribe Deltochilini Lacordaire. A molecular phylogeny of the southern African members of Sisyphini supports Epirinus as sister to Sisyphus Latreille and recovered three major clades in Sisyphus classified here as subgenera Sisyphus (Neosisyphus Müller) stat. rev. , Sisyphus (Parasisyphus Barbero, Palestrini & Zunino) stat.n. and Sisyphus (Sisyphus) stat.n. A molecular clock analysis suggests that Sisyphus and Epirinus diverged from their last common ancestor during the Lower to Middle Oligocene (c. 29.37 Ma). Biogeographical analysis indicated that southern African Sisyphus species are centred in the east and northeast in Highveld grassland and warmer savannah regions. By contrast, Epirinus species are largely restricted to the southwest and southeast in the cooler winter and bimodal rainfall regions plus arid highland Karoo and Highveld grasslands. Based on morphological and biogeographical differences between Epirinus and Sisyphus, we propose that the monogeneric Epirinus be placed in its own tribe, Epirinini van Lansberge stat. rev.     

Extensive genetic differentiation in Gobiomorphus breviceps from New Zealand

Partial mitochondrial DNA sequences for parts of the cytochrome b gene and control region were obtained for 89 upland bullies Gobiomorphus breviceps from 19 catchments in New Zealand. There were two highly distinctive mtDNA clades: a northern clade corresponding to the North Island, northern South Island and west coast South Island, and a south‐east clade, in the southern and eastern South Island. Within these major clades there were further distinct clades that correlated with geographic sub‐regions and catchments. The marked genetic differentiation has occurred in the absence of obvious morphological divergence. Based on cytochrome b sequence divergences and the molecular clock hypothesis, the northern and southeastern clades correspond with the uplift of the Southern Alps during the Pliocene, while populations in the North Island and northern South Island were estimated to have diverged during the Pleistocene. The widescale geographic divergences were similar to those observed in the galaxiids, Galaxias vulgaris and Galaxias divergens , but biogeographic management boundaries may not be the same, reflecting different evolutionary histories for non‐diadromous species occupying the same areas.     

The occurrence of Acanthurus monroviae(Perciformes: Acanthuridae) in the south‐western Atlantic, with comments on other eastern Atlantic reef fishes occurring in Brazil

The presence of 'vagrants' of the eastern Atlantic surgeonfish Acanthurus monrovia e is confirmed for the south‐eastern coast of Brazil. Three other species, Aulostomus strigosus (Aulostomidae), Parablennius pilicornis (Blenniidae) and Epinephelus marginatus (Serranidae) have apparently also crossed the Atlantic from east to west, whereas the great majority of 'amphi‐Atlantic' species appears to have their origin in the western Atlantic.     

Historical biogeography of scarabaeine dung beetles

Abstract Aim (1) To review briefly global biogeographical patterns in dung beetles (Coleoptera: Scarabaeidae: Scarabaeinae), a group whose evolutionary history has been dominated by ecological specialization to vertebrate dung in warmer climates. (2) To develop hypotheses accounting for the evolution of these patterns. Location Six principal biogeographical regions: Palaearctic, Oriental, Afrotropical, Australasia, Neotropical, Nearctic and five outlying islands or island groups harbouring endemic genera: Caribbean, Madagascar, Mauritius, New Caledonia, New Zealand. Methods Major patterns of tribal, generic and species distribution are investigated using cluster analysis, ordination, parsimony analysis of endemism and track analysis. Attempts are made to resolve biogeographical patterns with findings in the fields of plate tectonics, fossil and evolutionary history, plus phylogeny of both mammals and dung beetles. Results Because of conflict between published findings, it is uncertain at what point in time density of dinosaur dung, mammal dung or both became sufficiently great to select for specialized habits in dung beetles. However, biogeographical evidence would suggest a Mesozoic origin followed by further taxonomic radiation during the Cenozoic, possibly in response to the increasing size and diversity of mammalian dung types in South America and Afro‐Eurasia. Proportional generic distribution in fourteen tribes and subtribes showed four principal biogeographical patterns: (1) southerly biased Gondwanaland distribution, (2) Americas or (3) Madagascar endemism, and (4) northerly biased, Afro‐Eurasian‐centred distribution with limited numbers of genera also widespread in other regions. Proportional composition of faunas in eleven geographical regions indicated three principal distributional centres, East Gondwanaland fragments, Afro‐Eurasia and the Americas. These patterns probably result from three principal long‐term range expansion and vicariance events (Mesozoic: Gondwanaland interchange and fragmentation, Cenozoic: Afro‐Eurasian/Nearctic interchange and the Great American interchange). It is suggested that old vicariance caused by the Mesozoic fragmentation of Gondwanaland leads to a high degree of regional endemism at generic or tribal level across one or more Gondwanaland tracks. In contrast, it is suggested that the more recent Cenozoic range expansions occurred primarily towards northern regions leading to endemism primarily at species level. These Cenozoic radiations were facilitated by the re‐linking of continents, either because of tectonic plate movements (Africa to Eurasia in Miocene), climatically induced sea‐level change (Afro‐Eurasia to Nearctic in Miocene and Pleistocene), or similar coupled with orogenics (Nearctic to Neotropical in Pliocene). Speciation has followed vicariance either because of climatic change or physical barrier development. These recent range expansions probably occurred principally along an Afro‐Eurasian land track to the Nearctic and Neotropical and an Americas land track northwards from the Neotropics to the Nearctic, with limited dispersal from Eurasia to Australia, probably across a sea barrier. This accounts for the overall, spatially constrained, biogeographical pattern comprising large numbers of species‐poor genera endemic to a single biogeographical region and fewer more species‐rich genera, many of which show wider biogeographical distributions. In most southerly regions (Australasia, Madagascar, Neotropical), faunal composition and generic endemism is primarily dominated by elements with Gondwanaland ancestry, which is consistent with the Gondwanaland origin claimed for Scarabaeinae. In Afro‐Eurasia (Palaearctic, Oriental, Afrotropical), generic endemism of monophyletically derived Afro‐Eurasian and widespread lineages is centred in the Afrotropical region and faunal composition is numerically dominated by Afro‐Eurasian and widespread elements. In the Nearctic region, the fauna is jointly dominated by widespread elements, derived from Afro‐Eurasia, and Gondwanaland and Americas elements derived from the Neotropical region. Main conclusions Global biogeographical patterns in scarabaeine dung beetles primarily result from Mesozoic and Cenozoic range expansion events followed by vicariance, although recent dispersal to Australia may have occurred across sea barriers. Detailed phylogenetics research is required to provide data to support dispersal/vicariance hypotheses.     

Temporal coexistence of dung-dweller and soil-digger dung beetles (Coleoptera, Scarabaeoidea) in contrasting Mediterranean habitats

The western part of the Mediterranean basin is a transitional biogeographical region for the distribution of the representatives of the main guilds of dung beetles; towards the south, Aphodiinae (dung-dwellers) become scarce, whereas northwards Scarabaeinae (soil-diggers) progressively disappear. The number of species in local dung beetle assemblages is enhanced by this double faunistic contribution. Annual dung beetle assemblages were sampled in two sub-Mediterranean sites, which differed by 600 m in elevation, in order to determine the phenological dynamics related to the way of using dung (dung-dwellers/Aphodiinae vs. soil-diggers/Scarabaeinae and Geotrupinae). Aphodiids were active all year round, although they were affected by summer drought and, at high elevation, by the length of the cold season. This reduced activity was related to an impoverishment of Aphodiinae and to reduced temporal segregation between species. In contrast, soil-diggers were not active all year round and showed different species assemblages in the two sites. An extension of the activity period of these beetles was observed due to the occurrence of cold resistant species at high elevation. Our results suggested that the occurrence of soil-diggers seemingly did not affect the seasonality of dung-dwellers; their local abundance showed no negative correlation and, most importantly, phenological differences between dung-dwellers were always significantly higher than the seasonal differences between dwellers and diggers.     

How dung beetles respond to a human‐modified variegated landscape in Mexican cloud forest: a study of biodiversity integrating ecological and biogeographical perspectives

Aim To analyse how the dung beetles (Scarabaeinae) respond to a modified, variegated landscape, taking into account the biogeographical peculiarities of the Mexican Transition Zone. Location This study covers cloud forest (CF) of the Sierra Norte de Puebla mountain range and part of the Sierra Madre Oriental mountain range (Mexico). Methods We applied proportional sampling based on the landscape variegation model with Scarabaeinae as the indicator group, and using two approaches: structural units (vegetation type) and spatial units (windows). We used two measures – richness and Shannon diversity – and applied multiplicative diversity partitioning to obtain independent alpha and beta diversities for the landscape, windows and vegetation types. We grouped species by biogeographical distribution pattern for the biogeographical analysis and by whether they were originally from CF. Results The transformation of CF into secondary forest, pastures and other types of vegetation increases the Scarabaeinae diversity of the landscape, in vegetation types and windows. This increase is the result of species arriving from the tropical lowlands. However, the original dung beetle community of the CF dominates at different scales in the number of species, abundance and biomass. With increasing habitat modification, beta diversity increases in the windows, and species with the Tropical Palaeoamerican distribution pattern increase in abundance in vegetation types and windows. Main conclusions The variegated character of the landscape explains well the distribution and diversity of this dung beetle community. The peculiar characteristics of the Mexican Transition Zone have an effect owing to the overlap of fauna with different biogeographical origins. The conversion of fragmented landscapes to variegated landscapes could be a conservation goal in human‐modified mountain landscapes. Sampling proportional to the area of different types of vegetation and the use of windows offer an alternative experimental design in variegated landscapes.     

A review of the genus Malakichthys Döderlein (Perciformes: Acropomatidae) with the description of a new species

Malakichthys Döderlein, 1883, comprises seven species: type species Malakichthys griseus Döderlein 1883, from southern Japan to north‐western Australia; Malakichthys barbatus Yamanoue & Yoseda, 2001 , from southern Japan, the South China Sea, north‐western Australia and the Coral Sea; Malakichthys elegans Matsubara & Yamaguti, 1943 , from southern Japan south to the Arafura Sea; Malakichthys levis Yamanoue & Matsuura, 2001 , from northern Australia; Malakichthys mochizuki Yamanoue & Matsuura, 2001 , from the Coral Sea; Malakichthys similis sp. nov. from the Bohol Sea, Philippines; Malakichthys wakiyae Jordan & Hubbs, 1925 , from southern Japan and Taiwan. Species of Malakichthys are very similar to each other in general appearance but are distinguishable by spination on the lower jaw, features of the proximal‐middle radial of the first anal‐fin pterygiophore, the number of anal‐fin soft rays and body depth.     

Temporal and spatial variation in potential and realized growth rates of age‐0 year northern rock sole

The possibility of prey limitations on the growth performance of age‐0 year northern rock sole Lepidopsetta polyxystra was evaluated at three sites along the north‐east coast of Kodiak Island, Alaska, U.S.A., by comparison of observed to potential growth rates. Growth potential was measured in the laboratory across the range of temperatures encountered by this species during the first summer of life. Growth potential ( g _L, mm day⁻¹) increased with water temperature (T) between 2 and 13° C, according to: g _L = 0·0151 + 0·3673·log₁₀(T). There were significant differences in growth rate between the three field sites such that Holiday Beach fish were 7·1 mm longer than Shakmanof Beach fish by mid‐September, with Pillar Creek Cove fish of intermediate size. Temperature differences between sites accounted for less than half of this variation. The remainder may have been related to differences in prey availability among the sites in association with observed differences in sediment characteristics. In addition to the spatial variability, there was significant monthly variation in growth performance. Realized growth rates between July and August were in excess of 85% of potential. Between August and September, however, realized growth fell to 43–71% of potential indicating a decline in conditions for growth. The spatial variation in growth rates was not density‐dependent as the site with the highest fish densities (Holiday Beach) also supported the highest growth rates. The available data indicates that for this subtidal species, interannual variation in growth may be more important than site variation.     

Historical vs. ecological factors influencing global patterns of scarabaeine dung beetle diversity

Abstract. There has been much debate concerning the relative influence on biodiversity of historical vs. current ecological factors. Although both are important, we suggest that historical influences might be greater at higher taxonomic level, since one is looking further back into evolutionary history than at lower taxonomic level. Although we are unable to separate ecological from historical effects in the present global study on scarabaeine dung beetles, we are able to demonstrate differences in correlations between major environmental influences (climatic area, numbers of dung types) and major components of diversity (taxon richness, taxon diversity, functional composition) at different taxonomic levels (tribe, genus, species). Current global variation in taxon richness is correlated strongly to current biogeographical variation in the area of suitable climate at all three taxonomic levels. However, generic and species richness is correlated most strongly to climatic combinations which include tropical and warm summer rainfall climate types (I, II). In contrast, tribal richness is correlated most strongly to climatic combinations which include both warm summer rainfall and temperate climate types (II, VI, X). Regional variation in the number of available dung types shows a strong positive correlation to regional variation in taxon richness at higher tribal level but not at lower generic and species levels. Similarly, biogeographical differences in the number of available dung types show a strong negative correlation to dominance indices for taxon diversity at tribal level (distribution of generic numbers between tribes) but none at generic level (species numbers per genus). As functional diversification is linked closely to taxonomic diversification at tribal level, proportions of both ball‐rolling genera and ball‐rolling species also show strong negative correlations to the number of dung types available in each region. In conclusion, the presence of dung type correlations only at higher taxonomic level may reflect historical effects on scarabaeine taxon diversification, whereas differences in correlations to climate type with taxonomic level may reflect both current ecological and historical effects.