Focal Taxa Research Articles

Surrogate species versus landscape metric: does presence of a raptor species explains diversity of multiple taxa more than patch area?

Prioritizing conservation areas is a central theme in conservation biology. The use of surrogate species and landscape metrics to identify areas with high conservation value is common. However, few studies have examined the relative efficacy of these two surrogates. In this study, we compared the efficacy of the presence/absence (PA) of a top predator (Eastern Marsh Harrier, Circus spilonotus) and wetland patch area on species richness, total abundance, and community composition of birds, plants, and small mammals, but species richness and community composition only for plants, in a fragmented wetland landscape. Although harrier PA was an effective indicator of the distribution of birds, it had no significant efficacy on the distributions of plants and small mammals. Patch area was more effective indicator of the distributions of plants and small mammals. These results suggest that surrogate species can be more effective indicators than landscape surrogates when there are ecological linkages between surrogate species and the focal taxa (e.g., similarity of habitat requirements between surrogate species and focal taxa or hetero-specific attraction). On the other hand, landscape surrogates would be useful when ecological knowledge about the relationships is limited.

Drivers and Patterns of Ground-Dwelling Beetle Biodiversity across Northern Canada.

Many macroecological patterns of biodiversity, including the relationship between latitude and species richness, are well-described. Data collected in a repeatable, standardized manner can advance the discipline beyond the description of patterns and be used to elucidate underlying mechanisms. Using standardized field methods and a hyper-diverse focal taxon, viz. Coleoptera, we aim to (1) describe large-scale latitudinal patterns of taxonomic diversity, functional diversity, and assemblage structure across northern Canada, and (2) determine which climatic, spatial, and habitat variables best explain these patterns. We collected terrestrial beetles at twelve locations in the three northernmost ecoclimatic zones in North America: north boreal, subarctic, and high arctic (51–81°N, 60–138°W). After identifying beetles and assigning them to a functional group, we assessed latitudinal trends for multiple diversity indices using linear regression and visualized spatial patterns of assemblage structure with multivariate ordinations. We used path analysis to test causal hypotheses for species and functional group richness, and we used a permutational approach to assess relationships between assemblage structure and 20 possible climatic and environmental mechanisms. More than 9,000 beetles were collected, representing 464 species and 18 functional groups. Species and functional diversity have significant negative relationships with latitude, which are likely explained by the mediating effects of temperature, precipitation, and plant height. Assemblages within the same ecoclimatic zone are similar, and there is a significant relationship between assemblage structure and latitude. Species and functional assemblage structure are significantly correlated with many of the same climatic factors, particularly temperature maxima and minima. At a large spatial extent, the diversity and assemblage structure of northern beetles show strong latitudinal gradients due to the mediating effects of climate, particularly temperature. Northern arthropod assemblages present significant opportunities for biodiversity research and conservation efforts, and their sensitivity to climate make them ideal targets for long-term terrestrial diversity monitoring.

Should invertebrates receive greater inclusion in wildlife research journals?

ABSTRACTInvertebrates are among the most diverse organisms on Earth, significantly contribute to ecosystem function and integrity, and possess high potential as bioindicators. By definition, invertebrates also are wildlife. Yet, inclusion of invertebrates in peer‐reviewed wildlife journals has not been investigated. As such, our objective was to assess inclusion of invertebrates in prominent wildlife journals published in the last decade. Based on our review and first‐hand experience, we also aimed to provide recommendations for integration of invertebrates into wildlife science, education, and peer‐reviewed literature. We performed a systematic literature review by manually searching all issues and articles from 2003–2013 of the following journals: European Journal of Wildlife Research, Journal of Wildlife Management, South African Journal of Wildlife Research, Wildlife Biology, Wildlife Research, and Wildlife Society Bulletin. We analyzed data derived from our review to elucidate trends in the inclusion of invertebrates in these journals. We identified 4,916 articles that involved animal taxa, of which 122 (2.5%) included invertebrates and <1% included invertebrates as focal taxa. Our results indicated invertebrates are included in a minute portion of articles in top wildlife journals. We recommend a paradigm shift to a less taxonomically homogenized and vertebrate‐centric approach to wildlife science and education, integrating invertebrates into wildlife studies, and publishing results of those studies in wildlife journals to facilitate effective management of all wildlife species. © 2015 The Wildlife Society.

Relating environmental change and species stability in Late Ordovician seas

Niche stability of a diverse suite of 21 invertebrate species and genera from the Cincinnatian Series (Katian Stage) of North America was examined using spatial distribution modeling across nine time slices, including abiotic and biotic environmental change. Niche stability varied through time. The focal taxa exhibited niche stability ( = no adaptive response) and tracked their preferred environment laterally to accommodate gradual sea-level fall. Niche evolution increased during the Richmondian Invasion. Species adjusted to the introduction of new competitors by contracting their niche into a subset of their previous niche parameters. In Cincinnatian species and genera, adaptive response (stability vs. evolution) was related to the tempo and mode of environmental change.

Phylogenetic paleobiogeography of Late Ordovician Laurentian brachiopods; pp. 189–194

Phylogenetic biogeographic analysis of four brachiopod genera was used to uncover large-scale geologic drivers of Late Ordovician biogeographic differentiation in Laurentia. Previously generated phylogenetic hypotheses were converted into area cladograms, ancestral geographic ranges were optimized and speciation events characterized as via dispersal or vicariance, when possible. Area relationships were reconstructed using Lieberman-modified Brooks Parsimony Analysis. The resulting area cladograms indicate tectonic and oceanographic changes were the primary geologic drivers of biogeographic patterns within the focal taxa. The Taconic tectophase contributed to the separation of the Appalachian and Central basins as well as the two midcontinent basins, whereas sea level rise following the Boda Event promoted interbasinal dispersal. Three migration pathways into the Cincinnati Basin were recognized, which supports the multiple pathway hypothesis for the Richmondian Invasion.

Uncovering cryptic diversity and refugial persistence among small mammal lineages across the Eastern Afromontane biodiversity hotspot

The Eastern Afromontane region of Africa is characterized by striking levels of endemism and species richness accompanied by significant conservation threat, a pattern typical across biodiversity hotspots. Using multi-locus molecular data under a coalescent species tree framework we identify major cryptic biogeographic patterns within and between two endemic montane small mammal species complexes, Hylomyscus mice and Sylvisorex shrews, co-distributed across the Albertine Rift and Kenya Highlands of the Eastern Afromontane Biodiversity Hotspot (EABH). Hypotheses put forward to account for the high diversity of the region include retention of older palaeo-endemic lineages across major regions in climatically stable refugia, as well as the accumulation of lineages associated with more recent differentiation between allopatric populations separated by unsuitable habitat during periods of Pleistocene aridification. Sympatric pairs of sister lineages were found to have significantly older divergence times than allopatric pairs. Genetic analyses and historical distribution modeling suggest that regional meta-populations have persisted since the Pliocene to mid-Pleistocene across a climatic gradient from the Albertine Rift in the west to the Kenya Highlands in the east for both focal taxa. Differing patterns of regional sub-division and demographic expansion were detected and are consistent with differing life histories as well as shared responses to regional variation in stability of suitable habitat. There is also strong support in both mice and shrew species for Late Miocene divergence with subsequent range expansion into sympatry in previously unidentified cryptic species pairs. These results highlight the broad temporal scale at which climatic and geological changes may have facilitated rare dispersal events between montane habitats as well as the long-term persistence of populations in both the Albertine Rift and the Kenyan Highlands that together contributed to the high species diversity and endemism in the EABH.

Potential of ants and beetles as indicators of rainforest restoration: characterising pasture and rainforest remnants as reference habitats

SummaryAssessment of habitat restoration requires baseline information on the communities present in both converted and intact forms of the focal ecosystem to enable comparisons with restored sites. Ants and beetles are commonly used in ecological monitoring programmes, as they display assemblage‐level responses to habitat change and can be a more direct measure of the recommencement of some ecosystem functions than the presence of more obvious biota such as plants. However, as these taxa differ substantially in ecological traits, their response patterns and utility as potential bioindicators may vary. Using pitfall traps, we compared assemblages of ant and beetle species between two reference habitats, pasture and remnant rainforest in subtropical eastern Australia. The assemblage composition of both groups differed significantly between rainforest and pasture but only beetles showed accompanying differences in species richness and abundance, which were both significantly lower in pasture. We identified ant and beetle species characteristic of either pasture or rainforest remnants, which may be used as bioindicators in future monitoring programmes. These species, however, displayed patchy distributions, suggesting that the use of individual species as bioindicators is likely to be unreliable. These findings support the use of ‘composite habitat indices’, which combine information from sets of indicator species. Given that patterns of change in species composition were similar between ants and beetles, either is an appropriate focal taxon for future monitoring programmes. Beetles, however, displayed some limitations as no species were indicative of the disturbed pasture habitat. Ants and beetles are likely to respond in different ways to different aspects of habitat change; thus, using both together could strengthen assessments of rainforest degradation or recovery.

Optimising Bait for Pitfall Trapping of Amazonian Dung Beetles (Coleoptera: Scarabaeinae)

The accurate sampling of communities is vital to any investigation of ecological processes and biodiversity. Dung beetles have emerged as a widely used focal taxon in environmental studies and can be sampled quickly and inexpensively using baited pitfalls. Although there is now a wealth of available data on dung beetle communities from around the world, there is a lack of standardisation between sampling protocols for accurately sampling dung beetle communities. In particular, bait choice is often led by the idiosyncrasies of the researcher, logistic problems and the dung sources available, which leads to difficulties for inter-study comparisons. In general, human dung is the preferred choice, however, it is often in short supply, which can severely limit sampling effort. By contrast, pigs may produce up to 20 times the volume. We tested the ability of human and pig dung to attract a primary forest dung beetle assemblage, as well as three mixes of the two baits in different proportions. Analyses focussed on the comparability of sampling with pig or human-pig dung mixes with studies that have sampled using human dung. There were no significant differences between richness and abundance sampled by each bait. The assemblages sampled were remarkably consistent across baits, and ordination analyses showed that the assemblages sampled by mixed dung baits were not significantly different from that captured by pure human dung, with the assemblages sampled by 10% and 90% pig mixes structurally most similar to assemblages sampled by human dung. We suggest that a 10:90 human:pig ratio, or similar, is an ideal compromise between sampling efficiency, inter-study comparability and the availability of large quantities of bait for sampling Amazonian dung beetles. Assessing the comparability of assemblage samples collected using different baits represents an important step to facilitating large-scale meta-analyses of dung beetle assemblages collected using non-standard methodology.

Elevational Distribution and Conservation Biogeography of Phanaeine Dung Beetles (Coleoptera: Scarabaeinae) in Bolivia

Insect macroecology and conservation biogeography studies are disproportionately scarce, especially in the Neotropics. Dung beetles are an ideal focal taxon for biodiversity research and conservation. Using distribution and body size data on the ecologically important Phanaeini, the best-known Neotropical dung beetle tribe, we determined elevational patterns of species richness, endemism, body size, and elevational range in Bolivia, specifically testing Bergmann’s and Rapoport’s rule. Richness of all 39 species and of 15 ecoregional endemics showed a hump-shaped pattern peaking at 400 m, but overall declined strongly with elevation up to 4000 m. The relationship between endemic and total species richness appeared to be curvilinear, providing only partial support for the null hypothesis that species-rich areas are more likely to be centers of endemism by chance alone. An elevational increase in the proportion of ecoregional endemics suggests that deterministic factors also appear to influence endemism in the Andes. When controlling for the effect of area using different species-area relationships, the statistically significant richness peak became more pronounced and shifted upslope to 750 m. Larger species did not have higher elevational mid-points, and mean body size decreased significantly with elevation, contradicting Bergmann’s rule. Rapoport’s rule was supported: species with higher elevational mid-points had broader elevational ranges, and mean elevational range increased significantly with elevation. The elevational decrease of phanaeine richness is in accordance with studies that demonstrated the combined influence of temperature and water availability on species diversity, but also is consistent with niche conservatism. For invertebrates, confirmation of Rapoport’s and refutation of Bergmann’s rule appear to be scale-invariant general patterns. Analyses of biogeographic patterns across elevational gradients can provide important insights for identifying conservation priorities. Phanaeines with narrow elevational ranges on isolated low-elevation mountains in eastern Bolivia are at greatest climate-change related extinction risk from range-shift gaps and mountaintop extinctions.

Exploring the mesofilter as a novel operational scale in conservation planning

Summary Increased emphasis is being placed on developing effective biodiversity conservation tools for practical conservation planning. The mesofilter is such a biodiversity planning tool, but has yet to be fully explored to appreciate its effectiveness. The key premise of the mesofilter is that ecosystems contain certain physical elements that are specifically associated with a diversity of species. Identifying such mesofilters could therefore complement existing conservation planning tools such as coarse and fine filters. To explore the value of the mesofilter as an operational scale in conservation planning, we studied 18 remnant patches of endangered montane grassland in KwaZulu‐Natal, South Africa, using the physical landscape feature of patch rockiness as an abiotic surrogate for biodiversity. The objective was to determine whether the mesofilter of rockiness can predict variation in species richness and composition for three dominant grassland taxa (plants, butterflies and grasshoppers) at the landscape scale. Variable levels of rockiness had significant interactions with all three focal taxa. Higher species richness of all taxa was closely associated with higher levels of rockiness in a patch. The rocky mesofilter only predicted significant differences in species composition for butterflies. Elevation was also important, possibly another mesofilter for plants and grasshoppers in this landscape. Synthesis and applications. The results indicate that the use of an abiotic surrogate such as rockiness can predict biodiversity value across multiple taxa. The mesofilter is therefore a valuable surrogacy and congruency tool for practical biodiversity conservation across this landscape and would likely have similar value if explored elsewhere. It also has value in the design and management of protected areas.

Online appendix 1:Invertebrates on isolated peaks in the uKhahlamba-Drakensberg Park World Heritage Site, South Africa

A survey to document and describe the alpine flora and various focal faunal taxa on six isolated inselberg-like peaks (total area of 31.9 ha), all 3000 m or higher, located in the uKhahlamba-Drakensberg Park World Heritage Site, South Africa, was undertaken in early summer in 2005. Study of the fauna of these peaks should be informative because the impacts of controllable anthropogenic threats on the invertebrate communities on them should be minimal or absent in comparison with those on the main massif. A total of 341 invertebrate individuals representing 61 species were recorded from the focal taxa (Oligochaeta, Gastropoda and certain groups of Insecta, i.e. focal taxa within the Blattoidea, Dermaptera, Orthoptera, Hemiptera, Diptera, Lepidoptera, Coleoptera and Hymenoptera). The 61 species recorded consisted of two species from the Oligochaeta, one species from the Gastropoda and 58 species from the Insecta. Eleven species (one from the Oligochaeta, ten from the Insecta) are endemic and 11 species (one from the Oligochaeta, ten from the Insecta) are probably endemic to the Drakensberg Alpine Centre, constituting 36.1% of the total species recorded. The results suggest that the Drakensberg Alpine Centre (DAC), as for plants, is a centre of endemism for invertebrates. Cluster analysis showed that the species composition of the two northern peaks, Sentinel and Eastern Buttress, clustered together, separate from a cluster formed by the Outer Horn, Inner Horn and Dragon’s Back and from the cluster formed by the southernmost peak, Cathkin. Non-metric multi-dimensional scaling results indicated that distance from the Sentinel, the most northerly peak sampled, and mean minimum temperature for July had the strongest correlations with the species data, reflecting change over a straight-line distance of nearly 60 km in a south-easterly direction.Conservation implications: Only a small proportion (ca. 5.5%) of the DAC is conserved, the majority of which lies in the uKhahlamba-Drakensberg Park World Heritage Site. Conservation of more of the DAC, including more of its latitudinal extent, is required to adequately conserve its unique plant and invertebrate communities.

Testing morphology-based delimitation of Vulpicida juniperinus and V. tubulosus (Parmeliaceae) using three molecular markers

AbstractThe delimitation of two morphologically similar and not easily separable Vulpicida species, V. juniperinus and V. tubulosus, is analyzed using nuclear ITS and Mcm7, and mitochondrial SSU DNA sequences. Seventy-nine Vulpicida specimens, most from the two focal taxa, are included in the three-locus gene tree. The results from Bayesian and parsimony analyses are presented. There are strong conflicts between the single locus gene trees. Vulpicida juniperinus and V. tubulosus are divided into two clearly distinguished groups in the ITS and concatenated B/MCMC tree. However, these species are mixed in both clades, appearing polyphyletic. Currently accepted V. juniperinus and V. tubulosus are not distinct according to the loci studied. Vulpicida pinastri appears monophyletic based on the available sequences.

Biogeographic patterns and conservation priorities for the dung beetle tribePhanaeini (Coleoptera:Scarabaeidae:Scarabaeinae) inBolivia

AbstractThe New World Phanaeini are the best known Neotropical dung beetle tribe and a conservation priority among the Scarabaeinae, an ideal focal taxon for biodiversity research and conservation.We compiled a comprehensive distributional database for 39 phanaeine species in Bolivia and assessed patterns of species richness, body size and endemism in relation to abiotic variables and species richness and body mass of medium to large mammals across nine ecoregions.Pair‐wise linear regressions indicated that phanaeine richness, mean size and endemism are determined by different factors. In all cases mammal body mass had greater explanatory power than abiotic variables or mammal richness. Phanaeine richness was greater in ecoregions with on average smaller mammals and greater mammal richness. Mean phanaeine size increased with mean body mass of the largest herbivorous and omnivorous mammals. Endemism was greater in ecoregions with on average smaller herbivorous and omnivorous mammals. On average, smaller phanaeines had more restricted distributions than larger species; ecoregional endemism and mean body size were negatively correlated.Large phanaeines probably depend on large mammals to provide adequate food resources. Greater richness of smaller mammal species may allow for greater temporal and spatial resource partitioning and therefore greater phanaeine species richness. Low numbers of large mammal species may favour the persistence of geographically restricted phanaeine species by reducing interspecific competition with larger, more geographically widespread and presumably dominant phanaeines.Cerrado, Southwest Amazonia and Yungas are priority ecoregions for phanaeine conservation due to high total and endemic species richness.

Present taxonomic work on Staphylinidae (Coleoptera) in Canada: progress against all odds

Present taxonomic work on Staphylinidae (Coleoptera) in Canada: progress against all odds

Novel discovery of lamellar papillae on the grooming organ in Synsphyronus (Garypidae: Pseudoscorpiones)

The chelicerae, the first pair of appendages in Chelicerata, exhibit morphological and functional variation across arachnid orders. The two-segmented chelicerae of pseudoscorpions serve multiple functions including grooming, courtship, and grasping prey. Scanning electron microscopy was used to investigate structures found on the chelicera; the serrulae interiores and exteriores, grooming organs, were given special attention. Functional analogies were made between the cheliceral structures documented in pseudoscorpions and those found in other arthropods. The novel discovery of vestitural papillae and a patch of elongate papillae on the serrula exterior are reported. The focal taxon for the study is Synsphyronus (Garypidae), an Australasian genus.

Invertebrates on isolated peaks in the uKhahlamba-Drakensberg Park World Heritage Site, South Africa

A survey to document and describe the alpine flora and various focal faunal taxa on six isolated inselberg-like peaks (total area of 31.9 ha), all 3000 m or higher, located in the uKhahlamba-Drakensberg Park World Heritage Site, South Africa, was undertaken in early summer in 2005. Study of the fauna of these peaks should be informative because the impacts of controllable anthropogenic threats on the invertebrate communities on them should be minimal or absent in comparison with those on the main massif. A total of 341 invertebrate individuals representing 61 species were recorded from the focal taxa (Oligochaeta, Gastropoda and certain groups of Insecta, i.e. focal taxa within the Blattoidea, Dermaptera, Orthoptera, Hemiptera, Diptera, Lepidoptera, Coleoptera and Hymenoptera). The 61 species recorded consisted of two species from the Oligochaeta, one species from the Gastropoda and 58 species from the Insecta. Eleven species (one from the Oligochaeta, ten from the Insecta) are endemic and 11 species (one from the Oligochaeta, ten from the Insecta) are probably endemic to the Drakensberg Alpine Centre, constituting 36.1% of the total species recorded. The results suggest that the Drakensberg Alpine Centre (DAC), as for plants, is a centre of endemism for invertebrates. Cluster analysis showed that the species composition of the two northern peaks, Sentinel and Eastern Buttress, clustered together, separate from a cluster formed by the Outer Horn, Inner Horn and Dragon’s Back and from the cluster formed by the southernmost peak, Cathkin. Non-metric multi-dimensional scaling results indicated that distance from the Sentinel, the most northerly peak sampled, and mean minimum temperature for July had the strongest correlations with the species data, reflecting change over a straight-line distance of nearly 60 km in a south-easterly direction.Conservation implications: Only a small proportion (ca. 5.5%) of the DAC is conserved, the majority of which lies in the uKhahlamba-Drakensberg Park World Heritage Site. Conservation of more of the DAC, including more of its latitudinal extent, is required to adequately conserve its unique plant and invertebrate communities.

Does delaying the first mowing date benefit biodiversity in meadowland?

Background: Meadows are regularly mown in order to provide fodder or litter for livestock and to prevent vegetation succession. However, the time of year at which meadows should be first mown in order to maximize biological diversity remains controversial and may vary with respect to context and focal taxa. We carried out a systematic review and meta-analysis on the effects of delaying the first mowing date upon plants and invertebrates in European meadowlands. Methods: Following a CEE protocol, ISI Web of Science, Science Direct, JSTOR, Google and Google Scholar were searched. We recorded all studies that compared the species richness of plants, or the species richness or abundance of invertebrates, between grassland plots mown at a postponed date (treatment) vs plots mown earlier (control). In order to be included in the meta-analysis, compared plots had to be similar in all management respects, except the date of the first cut that was (mostly experimentally) manipulated. They were also to be located in the same meadow type. Meta-analyses applying Hedges’d statistic were performed. Results: Plant species richness responded differently to the date to which mowing was postponed. Delaying mowing from spring to summer had a positive effect, while delaying either from spring to fall, or from early summer to later in the season had a negative effect. Invertebrates were expected to show a strong response to delayed mowing due to their dependence on sward structure, but only species richness showed a clearly significant positive response. Invertebrate abundance was positively influenced in only a few studies. Conclusions: The present meta-analysis shows that in general delaying the first mowing date in European meadowlands has either positive or neutral effects on plant and invertebrate biodiversity (except for plant species richness when delaying from spring to fall or from early summer to later). Overall, there was also strong between-study heterogeneity, pointing to other major confounding factors, the elucidation of which requires further field experiments with both larger sample sizes and a distinction between taxon-specific and meadow-type-specific responses.

Using ecological niche modelling to evaluate niche stability in deep time

AbstractAim To investigate relative niche stability in species responses to various types of environmental pressure (biotic and abiotic) on geological time‐scales using the fossil record.Location The case study focuses on Late Ordovician articulate brachiopods of the Cincinnati Arch in eastern North America.Methods Species niches were modelled for a suite of fossil brachiopod species based on five environmental variables inferred from sedimentary parameters using GARP and Maxent. Niche stability was assessed by comparison of (1) the degree of overlap of species distribution models developed for a time‐slice and those generated by projecting niche models of the previous time‐slice onto environmental layers of a second time‐slice using GARP and Maxent, (2) Schoener’s D statistic, and (3) the similarity of the contribution of each environmental parameter within Maxent niche models between adjacent time‐slices.Results Late Ordovician brachiopod species conserved their niches with high fidelity during intervals of gradual environmental change but responded to inter‐basinal species invasions through niche evolution. Both native and invasive species exhibited similar levels of niche evolution in the invasion and post‐invasion intervals. Niche evolution was related mostly to decreased variance within the former ecological niche parameters rather than to shifts to new ecospace.Main conclusions Although the species examined exhibited morphological stasis during the study interval, high levels of niche conservatism were observed only during intervals of gradual environmental change. Rapid environmental change, notably inter‐basinal species invasions, resulted in high levels of niche evolution among the focal taxa. Both native and invasive species responded with similar levels of niche evolution during the invasion interval and subsequent environmental reorganization. The assumption of complete niche conservatism frequently employed in ecological niche modelling (ENM) analyses to forecast or hindcast species geographical distributions is more likely to be accurate for climate change studies than for invasive species analyses over geological time‐scales.

Macroecology of unicellular organisms – patterns and processes

Macroecology examines the relationship between organisms and their environment at large spatial (and temporal) scales. Typically, macroecologists explain the large-scale patterns of abundance, distribution and diversity. Despite the difficulties in sampling and characterizing microbial diversity, macroecologists have recently also been interested in unicellular organisms. Here, I review the current advances made in microbial macroecology, as well as discuss related ecosystem functions. Overall, it seems that microorganisms suit surprisingly well to known species abundance distributions and show positive relationship between distribution and adundance. Microbial species-area and distance-decay relationships tend to be weaker than for macroorganisms, but nonetheless significant. Few findings on altitudinal gradients in unicellular taxa seem to differ greatly from corresponding findings for larger taxa, whereas latitudinal gradients among microorganisms have either been clearly evident or absent depending on the context. Literature also strongly emphasizes the role of spatial scale for the patterns of diversity and suggests that patterns are affected by species traits as well as ecosystem characteristics. Finally, I discuss the large role of local biotic and abiotic variables driving the community assembly in unicellular taxa and eventually dictating how multiple ecosystem processes are performed. Present review highlights the fact that most microorganisms may not differ fundamentally from larger taxa in their large-scale distribution patterns. Yet, review also shows that many aspects of microbial macroecology are still relatively poorly understood and specific patterns depend on focal taxa and ecosystem concerned.

Weak responses to dietary enrichment in a specialized aphid predator

Some ladybeetles are specialist predators of aphids, coccids or other prey, although they often eat a variety of species from their focal prey taxon. In addition, the diet is often supplemented with alternative prey. How larvae of the aphidophagous Coccinella septempunctata L. utilize a non‐aphid alternative prey (fruit‐fly larvae Drosophila melonogaster Meigen) is compared with adequate (i.e. high‐quality) aphid prey provided alone (monotypic diet) or in mixed diets. The alternative prey are presented either nutrient‐enriched (i.e. raised on dog food supplemented medium) or not (raised on pure medium). Ladybird performance (survival, growth and development) is poor on the pure fly larvae diets, and also reduced when given mixed diets compared with the pure aphid diet. Nutrient enrichment of the fly larvae has no positive effects. The physiological background for the differences in food value, as indicated by performance in life‐history parameters, is a strong pre‐ingestive effect (i.e. reduced consumption of fly larvae compared with aphids) and a post‐ingestive effect (i.e. reduced utilization of assimilated larval fly tissue), whereas the assimilation efficiency of the consumed fly larvae is as high as that of aphids. The results show a physiological trade‐off resulting from prey specialization that reduces the possibility of utilizing alternative prey when the availability of aphids is scarce. Connected with this is a high robustness against variation in prey nutrient diversity and composition; the ladybird shows little positive response to dietary mixing (i.e. neither mixing of adequate aphids, nor of aphids and alternative prey) or to nutrient enrichment of prey. This contrasts with the results from generalist predators (spiders), where similar treatments lead to strong effects on life‐history parameters.