Peak In Richness Research Articles

A new RASS galaxy cluster catalogue with low contamination extending to z ∼ 1 in the DES overlap region

ABSTRACT We present the MARD-Y3 catalogue of between 1086 and 2171 galaxy clusters (52 per cent and 65 per cent new) produced using multicomponent matched filter (MCMF) follow-up in 5000 deg2 of DES-Y3 optical data of the ∼20 000 overlapping ROSAT All-Sky Survey source catalogue (2RXS) X-ray sources. Optical counterparts are identified as peaks in galaxy richness as a function of redshift along the line of sight towards each 2RXS source within a search region informed by an X-ray prior. All peaks are assigned a probability fcont of being a random superposition. The clusters lie at 0.02 < z < 1.1 with more than 100 clusters at z > 0.5. Residual contamination is 2.6 per cent and 9.6 per cent for the cuts adopted here. For each cluster we present the optical centre, redshift, rest frame X-ray luminosity, M500 mass, coincidence with NWAY infrared sources, and estimators of dynamical state. About 2 per cent of MARD-Y3 clusters have multiple possible counterparts, the photo-z’s are high quality with σΔz/(1 + z) = 0.0046, and ∼1 per cent of clusters exhibit evidence of X-ray luminosity boosting from emission by cluster active galactic nuclei. Comparison with other catalogues (MCXC, RM, SPT-SZ, Planck) is performed to test consistency of richness, luminosity, and mass estimates. We measure the MARD-Y3 X-ray luminosity function and compare it to the expectation from a fiducial cosmology and externally calibrated luminosity- and richness–mass relations. Agreement is good, providing evidence that MARD-Y3 has low contamination and can be understood as a simple two step selection – X-ray and then optical – of an underlying cluster population described by the halo mass function.

Principal factors controlling biodiversity along an elevation gradient: Water, energy and their interaction

AbstractAimVariation in diversity is a well‐documented spatial pattern in biogeography, but an overarching climate‐based theory of diversity is lacking. We evaluate two models of species richness related to species‐richness‐energy theory. One is based on net primary production (NPP) or the more individuals hypothesis (MiH), and the other is a model based on water–energy dynamics (WED). We use taxa from three kingdoms along an extensive elevation‐temperature gradient. Both WED and NPP‐MiH are based on thermal energy, but the question is whether energy operates through regulating production and chemical (potential) energy only (NPP‐MiH), or if kinetic energy as regulator of available liquid water is needed (WED).LocationCentral Himalayas.MethodsThe biodiversity, that is, elevational gamma diversity, of 12 taxa containing animals, plants, and fungi was estimated from range data along an elevation gradient. Generalized linear models were fitted to the species richness data, and the Akaike information criterion (AIC) and deviance explained were used to evaluate the NPP‐MiH and WED models. In addition, we tested the relationships with precipitation and length of growing season (LGS) and their interaction.ResultsThe peaks in richness of the taxa are dispersed along the entire Himalayan bioclimatic gradient from the subtropics to the alpine zone. WED performs best for all taxa along the entire gradient. In the non‐tropical zone, NPP‐MiH is best for reptiles, and NPP‐MiH and WED are equally good for mammals and amphibians. Including the length of the growing season in the WED model improves the AIC for eight taxa, and WED is superior for combined cross‐taxon biodiversity along the entire gradient, but WED and NPP‐MiH are equally good in the non‐tropical zone.ConclusionWater–energy dynamics is able to predict peaks in species richness under different climate and primary production conditions; hence, WED is better and more general than NPP‐MiH. The interaction with precipitation and the length of the growing season, which also reflects primary production, improve the model for several organism groups. Hence, LGS may improve and unify future mechanistic first‐principle model of biodiversity.

Butterfly diversity and effect of temperature and humidity gradients on butterfly assemblages in a sub-tropical urban landscape

The butterfly assemblages of urban ecosystems of Delhi were studied for a period of one year to investigate their diversity. The objective of the study was to understand the dynamics of the butterfly assemblages with respect to changing temperature and humidity levels. We tested the hypothesis that the diversity of butterflies would differ significantly across sampling period owing to pronounced temperature and relative humidity differences throughout the year. The Pollard walk method was used for butterfly survey. Twelve months of intensive sampling at four study sites with 24 temporal replicates per site yielded 14,913 individuals belonging to 75 species. Butterfly community showed a biannual peak of species richness and abundance. The maximum diversity was recorded in the pre-monsoon period between the months of April and May unlike most other studies from India which have reported April–May as the months of lowest diversity. The lowest diversity was observed during winter. Previous studies have shown that tropical insect communities have higher diversity during high precipitation periods. In this study, we found an additional peak of diversity during the pre-monsoon in addition to the post-monsoon months. The study quantitatively assessed community assemblages between ecosystems across a temperature gradient evaluating potential conservation role of natural areas and parks in urban landscapes.

Molecular diet analysis finds an insectivorous desert bat community dominated by resource sharing despite diverse echolocation and foraging strategies.

Interspecific differences in traits can alter the relative niche use of species within the same environment. Bats provide an excellent model to study niche use because they use a wide variety of behavioral, acoustic, and morphological traits that may lead to multi‐species, functional groups. Predatory bats have been classified by their foraging location (edge, clutter, open space), ability to use aerial hawking or substrate gleaning and echolocation call design and flexibility, all of which may dictate their prey use. For example, high frequency, broadband calls do not travel far but offer high object resolution while high intensity, low frequency calls travel further but provide lower resolution. Because these behaviors can be flexible, four behavioral categories have been proposed: (a) gleaning, (b) behaviorally flexible (gleaning and hawking), (c) clutter‐tolerant hawking, and (d) open space hawking. Many recent studies of diet in bats use molecular tools to identify prey but mainly focus on one or two species in isolation; few studies provide evidence for substantial differences in prey use despite the many behavioral, acoustic, and morphological differences. Here, we analyze the diet of 17 sympatric species in the Chihuahuan desert and test the hypothesis that peak echolocation frequency and behavioral categories are linked to differences in diet. We find no significant correlation between dietary richness and echolocation peak frequency though it spanned close to 100 kHz across species. Our data, however, suggest that bats which use both gleaning and hawking strategies have the broadest diets and are most differentiated from clutter‐tolerant aerial hawking species.

Plant richness pattern in an elevation gradient in the Eastern Himalaya

In spite of many theoretical explanations, the plant richness pattern along the mountain elevation gradient is still debatable. Here we considered East district of Sikkim state in the Eastern Himalaya to study plant richness pattern of vascular plants along an elevation gradient of 500–3300 m at 100, 200 and 300 m elevation steps. The study evaluates species-area relationships along the elevation gradient, spread over four major forest types i.e., low (tropical to sub-tropical, up to 900 m), middle (subtropical, 750–1500 m), upper (wet temperate, 1500–2700 m) and Rhododendron-Conifer Zone (cold temperate/sub-alpine, 2700–3600 m) with 664 species from 367 genera and 131 families. Pteridium aquilinum was found to be the most diverse species occurring in all 28-elevation steps along 500–3300 m, followed by Polystichum lentum, Polygonum runcinatum and Nephrolepis cordifolia those occured in 23 elevation steps. In general, a hump shaped pattern was observed for plant richness of all life forms along the elevation gradient. The peaks became prominent, with the increase in scale of extent from 100 m (R2 = 50%) to 300 m (R2 = 78%) through 200 m (R2 = 55%) elevation steps, using 2nd order polynomial fitting. The reduction in tree height and richness was noticed beyond 2300 m allowing dominance of herbs owing to climatic constraints. Using generalized additive model, temperature could explain the maximum deviance of > 47%. Soil explained 36.4% deviance, followed by precipitation (21.6% deviance) in the plant richness. However, the ecotone effect of different forest types explained the mid-elevation peaks in plant richness more prominently than the geographic area availability. Further, inclusion of disturbance and biotic interactions may improve ecological understandings on the plant richness pattern along the elevation gradient.

Drivers of elevational richness peaks, evaluated for trees in the east Himalaya.

Along elevational gradients, species richness often peaks at intermediate elevations and not the base. Here we refine and test eight hypotheses to evaluate causes of a richness peak in trees of the eastern Himalaya. In the field, we enumerated trees in 50 plots of size 0.1ha each at eight zones along an elevational gradient and compared richness patterns with interpolation of elevational ranges of species from a thorough review of literature, including floras from the plains of India. The maximum number of species peaks at similar elevations in the two data sets (at 500m in the field sampling and between 500m and 1,000m in range interpolation); concordance between the methods implies that statistical artefacts are unlikely to explain the peak in the data. We reject most hypotheses (e.g., area, speciation rate, mixing of distinct floras). We find support for a model in which climate (actual evapotranspiration [AET] or its correlates) sets both the number of species and each species optimum, coupled with a geometric constraint. We consider that AET declines with elevation, but an abrupt change in the association of AET with geographical distance into the plains means that the location of highest AET, at the base of the mountain, receives range overlaps from fewer species than the location just above the base. We formalize this explanation with a mathematical model to show how this can generate the observed low-elevation richness peak.

Drivers of Elevational Richness Peaks, Evaluated for Trees in the East Himalaya

Drivers of Elevational Richness Peaks, Evaluated for Trees in the East Himalaya

The type of nutrient limitation affects the plant species richness–productivity relationship: Evidence from dry grasslands across Eurasia

Abstract The species richness–productivity relationship is one of the most debated patterns in ecology. Species coexistence theory suggests that it could be tightly linked to the type of nutrient limitation (no limitation, single‐nutrient limitation, colimitation by several nutrients). Yet, the effects of nutrient limitation on the species richness–productivity relationship have been rarely studied at the regional and continental scales. Combining the predictions of the humped‐back model and the niche dimension hypothesis, we hypothesized that an increase in plant species richness with the number of different limiting nutrients is detectable only at higher productivity levels, at which competition for nutrients is more intense. Therefore, we expected the shape of the diversity–productivity relationship to differ between sites colimited by nitrogen (N) and phosphorus (P), sites limited by a single nutrient (either N or P), and sites not limited by any of these nutrients. To test this hypothesis, we used species richness data collected in 10 m × 10 m plots at 694 temperate dry grassland sites across eight regions in northern Eurasia. Productivity ranged from 10 to ~500 g/m2 of above‐ground standing biomass. The type of nutrient limitation was identified by critical nutrient ratios alone and their combination with critical nutrient concentrations measured in the plant tissue. Relationships were analysed using generalized linear and mixed‐effect models. In line with our expectations, species richness of Eurasian temperate dry grasslands increased more steeply and peaked higher under higher productivity levels at N&P‐colimited sites. When nutrient limitation was assessed by both ratios and concentrations, species richness at N&P‐colimited sites continued to increase monotonically until the maximum productivity sampled in this study. In contrast, at sites with a single‐nutrient limitation or no limitation, the peak in species richness was lower and occurred at a lower productivity of about 300–400 g/m2. Synthesis. We provide the first evidence that the species richness–productivity relationship may depend on the type of nutrient limitation as predicted by the species coexistence theory. To generalize these findings, the role of nutrient limitation needs to be tested in other ecosystems, including more productive plant communities.

A new tuskless walrus from the Miocene of Orange County, California, with comments on the diversity and taxonomy of odobenids.

We describe Titanotaria orangensis (gen. et. sp. nov.), a new species of walrus (odobenid) from the upper Miocene Oso Member of the Capistrano Formation of Orange County, California. This species is important because: (1) It is one of the best-known and latest-surviving tuskless walruses; (2) It raises the number of reported odobenid taxa from the Oso Member to four species making it one of the richest walrus assemblages known (along with the basal Purisima of Northern California); (3) It is just the second record of a tuskless walrus from the same unit as a tusked taxon. Our phylogenetic analysis places T. orangensis as sister to a clade that includes Imagotaria downsi, Pontolis magnus, Dusignathus spp., Gomphotaria pugnax, and Odobeninae. We propose new branch-based phylogenetic definitions for Odobenidae, Odobeninae, and a new node-based name (Neodobenia) for the clade that includes Dusignathus spp., G. pugnax, and Odobeninae. A richness analysis at the 0.1 Ma level that incorporates stratigraphic uncertainty and ghost lineages demonstrates maximum peaks of richness (up to eight or nine coeval lineages) near the base of Odobenidae, Neodobenia, and Odobenini. A more conservative minimum curve demonstrates that standing richness may have been much lower than the maximum lineage richness estimates that are biased by stratigraphic uncertainty. Overall the odobenid fossil record is uneven, with large time slices of the record missing on either side of the Pacific Ocean at some times and biases from the preserved depositional environments at other times. We recognize a provisional timescale for the transition of East Pacific odobenid assemblages that include “basal odobenids” (stem neodobenians) from the Empire and older formations (>7 Ma), to a mixture of basal odobenids and neodobenians from the Capistrano and basal Purisima (7–5 Ma), and then just neodobenians from all younger units (<5 Ma). The large amount of undescribed material will add new taxa and range extensions for existing taxa, which will likely change some of the patterns we describe.

Zehn Jahre Vegetationsdynamik auf der Waldbrandfläche von Leuk (Wallis)

Ten years of vegetation dynamics in a forest fire patch in Leuk (Valais) The stand-replacing forest fire of Leuk (2003) extends from 900 to 2100 m a.s.l. and covers an area of 300 ha, which represents a big disturbance event in Switzerland, although it is small in a global perspective. Its location along a wide elevational gradient has offered a unique opportunity to study the dynamics of plant species richness and natural tree regeneration in relation to different environmental drivers. The vegetation was assessed on a systematic grid including 148 relevé plots and 5 time steps. Results show a peak of species richness in the fourth year after the disturbance and a distinctly higher number of species compared to the pre-fire forests. The increase of species richness during the first four years was slower on plots with highest fire severity. Above 1600 m a.s.l. species richness rose quickly above average due to the appearance of various mountain species. Tree regeneration has advanced in all studied elevation belts. Ten years after the disturbance, sapling densities ≥25 cm reached a rather low level of 1800 to 3000 stems per hectare. Aspen (Populus tremula), willow (Salix appendiculata and S. caprea), as well as birch (Betula pendula) are most abundant up to 1700 m a.s.l., where up to 95% of the regeneration consists of broadleaves. Above, European larch (Larix decidua) and Norway spruce (Picea abies) each constitute 12% of the regenerating saplings. At lowest elevations, oaks (Quercus pubescens) have established more frequently (6.4%) after ten years than Scots pine (Pinus sylvestris; 3.7%), even though the proportion of these formerly stand-forming tree species is still quite modest compared to the total number of stems per ha. Looking ahead, a young forest will grow on the forest fire patch, developing towards a larch-spruce forest at high elevations and towards a mixed forest with a considerable proportion of oak at low elevations. It may take quite a while until prevailing aspen, willow and birch will be overgrown by conifers and oaks.

Landscape-scale effects of Christmas-tree plantations in an intensively used low-mountain landscape – Applying breeding bird assemblages as indicators

Novel ecosystems are characterised by recent establishment due to human activities and new species combinations. A characteristic example in farmlands are Christmas-tree plantations. The aim of this study is to evaluate the landscape-scale effects of the novel ecosystem Christmas-tree plantation on breeding bird assemblages in an important European stronghold of Christmas-tree production, the intensively used low-mountain landscape of the Hochsauerland (Central Europe), in comparison with currently competing land-use types.The study revealed that the five studied landscape types differed in habitat composition and landscape diversity. Landscape diversity was significantly highest in the two types of Christmas-tree plantation landscapes and windthrow landscapes, differing from grassland and forest landscapes. Bird species assemblages clearly responded to the differences in habitat composition. This was especially true for threatened species having a peak of species richness and breeding-pair density in the two types of Christmas-tree plantation landscapes and slightly weakened at windthrow landscapes.The high species richness of threatened breeding bird species in Christmas-tree plantation landscapes was driven mainly by high landscape heterogeneity. Densities of the threatened indicator species of the Christmas-tree plantation landscapes were probably promoted by (i) high availability of suitable food (arthropods, seeds) and (ii) high accessibility to the food resources due to bare ground (tree pipit [Anthus trivialis], woodlark [Lullula arborea]) or low-growing vegetation (linnet [Carduelis cannabina], yellowhammer [Emberiza citronella]) in the Christmas-tree plantations. For the woodlark, Christmas-tree plantations are even among the most important strongholds in the German Federal State of North Rhine-Westphalia.

The spatial structure of phylogenetic and functional diversity in the United States and Canada: An example using the sedge family (Cyperaceae)

AbstractSystematically quantifying diversity across landscapes is necessary to understand how clade history and ecological heterogeneity contribute to the origin, distribution, and maintenance of biodiversity. Here, we chart the spatial structure of diversity among all species in the sedge family (Cyperaceae) throughout the USA and Canada. We first identify areas of remarkable species richness, phylogenetic diversity, and functional trait diversity, and highlight regions of conservation priority. We then test predictions about the spatial structure of this diversity based on the historical biogeography of the family. Incorporating a phylogeny, over 400 000 herbarium records, and a database of functional traits mined from online floras, we find that species richness and functional trait diversity peak in the Northeastern USA, while phylogenetic diversity peaks along the Gulf of Mexico. Floristic turnover among assemblages increases significantly with distance, but phylogenetic turnover is twice as rapid along latitudinal gradients as along longitudinal gradients. These patterns reflect the expected distribution of Cyperaceae, which originated in the tropics but radiated in temperate regions. We identify assemblages with an abundance of rare, range‐restricted lineages, and assemblages composed of species generally lacking from diverse regions. We argue that both of these metrics are useful for developing targeted conservation strategies. We use the data generated here to establish future research priorities, including the testing of a series of hypotheses regarding the distribution of chromosome numbers, photosynthetic pathways, and resource partitioning in sedges.

Turnover and nestedness in subtropical dung beetle assemblages along an elevational gradient

AbstractAimWe investigated changes in dung beetle β‐diversity components along a subtropical elevational gradient, to test whether turnover or nestedness‐related processes drive the dissimilarity of assemblages at spatial and temporal scales.LocationAn elevational gradient (200–1,600 m a.s.l.) of the Atlantic Forest in southern Brazil.MethodsWe investigated the extent to which β‐diversity varied along the elevational gradient (six elevations) at both spatial (among sites at different elevations) and temporal (different months at the same site) scales. We compared both the turnover and nestedness‐related dissimilarity of species and genera using multiple‐site or multiple‐month measures and tested whether these measurements were different from random expectations.ResultsA mid‐elevation peak in species richness along the elevational gradient was observed, and the lowest richness occurred at the highest elevations. We found two different groups of species, lowland and highland species, with a mixing of groups at intermediate elevations. The turnover component of β‐diversity was significantly higher for both spatial (i.e. elevational) and temporal changes in species composition. However, when the data for genera by site were considered, the elevational turnover value decreased in relative importance. Nestedness‐related processes are more important for temporal dissimilarity patterns at higher elevation sites.Main conclusionsSpatial and temporal turnover of dung beetle species is the most important component of β‐diversity along the elevational gradient. High‐elevation assemblages are not subsets of assemblages that inhabit lower elevations, but this relationship ceases when β‐diversity is measured at the generic level. Environmental changes across elevations may be the cause of the differential establishment of distinctive species, but these species typically belong to the same higher taxonomic rank. Conservation strategies should consider elevational gradients in case‐specific scenarios as they may contain distinct species assemblages in lowlands vs. highlands.

Elevational and phytophysiognomic gradients influence the epiphytic community in a cloud forest of the Atlantic phytogeographic domain

Biological communities vary in composition and structure according to changes in the environment, such as in mountainous areas where temperature and moisture change with elevation, leading to gradual changes in vegetation. The altitudinal gradient is considered mirrors of the latitudinal gradient, although the richness peak can occur in the middle of the gradient, due to the greater total availability of moisture and/or due to the mid-domain effect. We aimed to test whether there was an intermediary peak in the richness of vascular epiphytes in two environmental gradients represented by elevation (around 1200–1700 m.s.m.) and by three subphysiognomies of cloud dwarf-forest in the Brazilian Atlantic Forest. For this purpose, 24 plots of 10 × 20 m were established and divided into eight sets in each subphysiognomy, along the altitudinal gradient. The community structure was analyzed by calculating the Shannon diversity index (H′), the Pielou uniformity index (J), and taxonomic diversity indices (Δ+ and Λ+). In total, 568 phorophytes were sampled, resulting in 3771 occurrences of epiphytes, distributed in 146 species. The diversity was different between the physiognomies of dwarf-forest and along the elevation gradient, and was specifically greater with higher elevation. The value of Δ+ was lower than expected in one plot, and represented a potential human impact. The obtained results highlight the diversity of this region and the important contribution of the epiphytes, as well as the sensitivity of epiphytic communities to the different vegetation physiognomies and the climatic variations caused by the elevation.

Patterns of diversity along a habitat size gradient in a biodiversity hotspot

AbstractHabitat destruction and loss are the gravest threats to wildlife worldwide. We examined the correlation between habitat patch size and species richness and abundance of mammals and reptiles in a biodiversity hotspot in California. Within nine forest fragments standardized for age, topography, climate, and vegetation cover, we tested the effects of patch size and isolation on biodiversity. To measure species richness and abundance, we used wildlife cameras for meso‐and‐large vertebrates, mark‐and‐recapture analyses for small mammals, mark‐and‐resight analysis for reptiles, and standard dragging techniques for tick collections because they are frequent ectoparasites on vertebrates in oak woodland habitats. Our results show that meso‐and‐large vertebrate richness and abundance increase with patch area as does tick density. Surprisingly, small mammal species richness and abundance peak in intermediate‐sized fragments. Resource limitation and competition at the smallest habitats and predation at the largest patches may be responsible for this pattern. Further, there is a significant decrease in invasive species richness with habitat patch size. We found that habitat destruction and fragmentation are acting upon species and communities in context‐dependent ways that is critical to conservation planning, land use design, and ecosystem function.

Overlap in avian communities produces unimodal richness peaks on Bornean mountains

Abstract:Altitudinal gradients provide tractable, replicated systems in which to study changes in species richness and community composition over relatively short distances. Previously, richness was often assumed to follow a monotonic decline with altitude, but recent meta-analyses show that more complex patterns, including mid-altitude richness peaks, are also prevalent in birds. In this study, we used point counts to survey birds at multiple altitudes on three mountains on the island of Borneo in Sundaland, an area for which quantitative analyses of avian altitudinal distribution are unavailable. In total we conducted 1088 point counts and collected associated habitat data at 527 locations to estimate species richness by altitude on Mt Mulu (2376 m), Mt Pueh (1550 m) and Mt Topap Oso (1450 m). On Mulu, the only mountain with an intact habitat gradient, bird species richness peaks at 600 m. Richness appeared to peak at 600 m on Totap Oso as well, but on Pueh it peaked several hundred metres higher. The richness peak on Mulu differs from that predicted by null models and is instead caused by the overlap of distinct lowland and montane avifaunas, supporting the faunal overlap hypothesis. This finding provides further evidence that a lack of coincidence between peak turnover and peak richness is not sufficient evidence to rule out faunal overlap as a causal factor.

Global elevational diversity and diversification of birds.

Mountain ranges harbour exceptionally high biodiversity, which is now under threat from rapid environmental change. However, despite decades of effort, the limited availability of data and analytical tools has prevented a robust and truly global characterization of elevational biodiversity gradients and their evolutionary origins. This has hampered a general understanding of the processes involved in the assembly and maintenance of montane communities. Here we show that a worldwide mid-elevation peak in bird richness is driven by wide-ranging species and disappears when we use a subsampling procedure that ensures even species representation in space and facilitates evolutionary interpretation. Instead, richness corrected for range size declines linearly with increasing elevation. We find that the more depauperate assemblages at higher elevations are characterized by higher rates of diversification across all mountain regions, rejecting the idea that lower recent diversification rates are the general cause of less diverse biota. Across all elevations, assemblages on mountains with high rates of past temperature change exhibit more rapid diversification, highlighting the importance of climatic fluctuations in driving the evolutionary dynamics of mountain biodiversity. While different geomorphological and climatic attributes of mountain regions have been pivotal in determining the remarkable richness gradients observed today, our results underscore the role of ongoing and often very recent diversification processes in maintaining the unique and highly adapted biodiversity of higher elevations.

Diversity of terrestrial isopod species in the Chambi National Park (Kasserine, Tunisia)

AbstractDiversity of terrestrial isopods across habitats and altitude was studied in the National Park of Chambi (central Tunisia). Samples were collected over five years in seven sites (S1–S7), within an altitudinal range from 750 to 1,500 m a.s.l. Twelve species belonging to five families were identified, with one endemic species (Porcellio djahizi) to this area, and three species were present in all sites (P. djahizi, Leptotrichus panzerii and Armadillidium tunisiense). Agnaridae represented by Hemilepistus reaumurii species was the most abundant family (58.77%) and found in only one site. Our results showed differences in species richness between sites. Indeed, S2 and S3 (900 and 1,050 m) showed the highest species richness with 11 species each. This result validates the hypothesis of mid‐elevational richness peak and contradicts the theory of large sampling regimes in determining the relationship between species richness and elevation. Terrestrial isopod species richness in the Chambi Mountain tends to decrease with altitude: 11 species in S2 and S3 to four species in S7. The highest Shannon–Wiener diversity index value was observed in S2 (H′ = 3.21 bits). Canonical correspondence analysis revealed that H. reaumurii was positively correlated with temperature whereas A. tunisiense and P. djahizi were the only species positively correlated with altitude.

Role of short-range order in manipulating light absorption in disordered media

Structural correlations have a significant effect on light propagation in disordered media. We numerically investigate the role of short-range order in light absorption in thin films with disordered nanoholes. Two types of disordered distributions, including stealthy hyperuniform (SHU) and hard disk (HD) patterns with different degrees of short-range order, are studied. We find that Bragg scattering induced by short-range order results in the appearance of a gradually sharper absorption peak with the increasing of degrees of short-range order ($\chi$, $\phi$). A physical model is proposed to calculate the in-plane angularly differential scattering cross section $d \sigma^*/d \theta$ of thin-film nanostructures with consideration of {the} structure factor $S(q)$. Results reveal that higher level of short-range order can enhance in-plane Bragg scattering in certain wavelengths and directions corresponding to rich and sharp peaks in {the} structure factor $S(q)$, which can further modify morphology-dependent-like resonances of an individual scatterer {and leads } to {large} improvement of absorptivity in thin films. Besides, the comparison results show that SHU structures exhibit better integrated absorption ($IA$) enhancement than both HD and periodic structures. And there is a transition of local-order phase between hexagonal lattice{s} and square lattice{s for SHU structures}, leading to an optimal absorption performance when $\chi$ is around 0.5 of interest. The present study paves a way in controlling light absorption and scattering using novel disordered nanostructures.

Variation in the species richness of parasitoid wasps (Ichneumonidae: Pimplinae and Rhyssinae) across sites on different continents

Abstract The old idea that parasitoid wasps (Ichneumonidae) show an inverse latitudinal diversity gradient has recently been challenged, but how ichneumonid species richness varies across the globe is still not well understood. We carried out field inventories in 21 sites on three continents to clarify this question, focusing on the subfamilies Pimplinae and Rhyssinae. Our total sampling effort was 628 Malaise trap months and the total catch exceeded 65 000 individuals. Our main focus was in two intensively inventoried areas in Amazonia, together yielding 257 Malaise trap months and 26 390 ichneumonid individuals. To expand the scope and assess global species diversity patterns of the Pimplinae and Rhyssinae, we compiled published species lists from a total of 97 study localities around the world. The highest observed species richness in any locality, 105 species, was found in one of our field sites in Peruvian Amazonia. None of the other localities reported more than 70 species, even the ones with a sampling effort comparable to ours. Despite the local thoroughness of our field inventories in Amazonia, data analyses indicated that a substantial proportion of the parasitoid wasp species occurring in each site remained unobserved. The highest local species richness values were reported from the tropics. Nevertheless parasitoid wasps are still too sparsely sampled to draw solid conclusions about whether or not their species richness follows a particular latitudinal trend, and if so, where their richness peaks.