Species richness has been shown to decrease, and elevational range increase (the Rapoport effect), with elevation as a consequence of biotic and abiotic factors, but patterns are inconsistent across taxonomic groups. Despite being an important indicator taxon and component of local communities, Orthoptera distributions at higher elevations in Europe remain unclear. We investigated the relationship of Orthoptera species richness and elevational range with elevation by conducting field studies at 28 sites across three study areas in the Pyrenees mountains, Europe. We found that species richness declined with elevation. Study area and the site-specific factors of sampling effort, topography (slope) and vegetation structure (density and cover) were also important predictors of species richness. We did not observe a Rapoport effect, with elevational range peaking at mid-elevation instead. Smaller elevational ranges found at high elevations may be due to a combination of sampling over a restricted elevational range and the presence of specialist high-elevation species. We also explored the composition of Orthoptera assemblages using multivariate methods, finding no clear effect of elevation, slope or vegetation structure on these communities, although study area somewhat influenced assemblages. To our knowledge, this is the first study of the Rapoport effect along an elevational gradient using insects as a study system in Europe. We argue that our findings are useful for understanding species distributions with elevation at the interface between local and regional scales. Clarifying the biotic and abiotic predictors of species distribution is important for informing conservation efforts and predicting consequences of climate change.

Fish play vital roles in river ecosystems; however, traditional investigations of fish usually cause certain ecological damage. Extracting DNA from aquatic environments and identifying DNA sequences offers an alternative, non-invasive approach for detecting fish species. In this study, environmental DNA (eDNA), coupled with PCR and next-generation sequencing, and electrofishing were used to compare their effects in identifying fish community characteristics. In three subtropical rivers of southern China, fish specimens and eDNA in water were collected from headwaters to estuaries. Both eDNA OTU richness and individual abundance (including number and biomass) could group 38 sampling sites into eight spatial zones with significant differences in local fish community composition. Compared with the order-/family-level grouping, the genus-/species-level grouping could more accurately recognize the differences between upstream zones I − III, midstream zones IV − V, and downstream zones VI – VIII. From headwaters to estuary, two environmental gradients significantly influenced the longitudinal distribution of fish species, including the first gradient composed of habitat and physical water parameters and the second gradient composed of chemical water parameters. The high regression coefficient of alpha diversity between eDNA and electrofishing methods as well as the accurate recognition of dominant, alien, and biomarker species at each spatial zone indicated that eDNA could characterize fish community attributes at a similar level of traditional approach. Generally, our results demonstrated that eDNA metabarcoding can be used as an effective tool in revealing fish composition and diversity, which is important for using the eDNA technique in aquatic field monitoring.

Root system architecture is limited by phylogenetic relationships and ultimately affect the biomass allocation of resource acquisition organs. However, many studies have only focused on the impact of environmental driven trait variation and biomass allocation on root system architecture, neglecting the impact of phylogenetic relationships. Therefore, biomass allocation and phylogenetic relationship affect the root system architecture and its variation patterns were investigated in annual ephemerals. We found that the interspecific variation of root tissue density (RTD) was the highest (51.63%), and the topological index (TI) was the lowest (5.92%). Moreover, the range of intraspecific variation for specific root length (SRL) and specific surface area (SRA) is high, and the TI is low. This convergence and divergence of root traits reflect the Phenotypic plasticity of roots and their adaptation to environmental filtering and interspecific competition. Maximum root depth (MRD) was detected significantly and weakly phylogenetic signal (0

Climate change is likely to drive widespread species range shifts and extirpations, mostly on the warm distribution edges, where habitat tends to be fragmented, of lower quality, support lower population density, and at greater risk from extreme weather events. In the Intermountain West, future climate will likely be warmer and drier, driving a reduction in sagebrush (Artemesia sp.) and other shrubland cover. Among the species threatened by more xeric climate is the Greater sage-grouse (Centrocercus urophasianus), which depends on sagebrush for forage and shelter, though their response to temperature is not well studied. We deployed 75 data loggers across two valleys in southern Utah and Nevada, near the southern edge of sage-grouse distribution, and collected temperature data for 27 months. We used random forest models to test the impacts of temperature, land cover, and topography on sage-grouse habitat selection and found that temperature influenced selection in all seasons and both sites. In Utah, the warmer site, sage-grouse selected areas near trees during the extremes of both winter and summer. In autumn and spring those extremes were rarer and sage-grouse avoided habitat near trees. Conversely, sage-grouse in the cooler Nevada site selected contiguous patches of sagebrush in extremes periods but only selected habitat near trees during winter cold, avoiding trees during summer. Our findings show that extreme temperatures drive sage-grouse to select habitat near trees despite the risk likely posed by avian predators. The difference between the Utah and Nevada sites suggests that sage-grouse prefer sagebrush as thermal shelter but that it may be inadequate during the hottest times, forcing riskier selection. These models point toward a more mechanistic understanding of how sage-grouse distribution may retract at its warm edges. This will refine our understanding of seasonal habitat requirements and inform management decisions to prioritize thermal refugia for an imperiled species.

Although natural flooding plays a crucial role in shaping the composition of aquatic communities, most rivers around the world have been regulated or dammed for anthropogenic purposes. This affects the biological and chemical composition of these ecosystems. Although studies have demonstrated the negative effects of river regulation on aquatic invertebrate communities globally, there is a scarcity of research in Africa, despite its vulnerability to anthropogenic use. This study aimed to compare aquatic invertebrate communities between the regulated Phongolo River and the unregulated Usuthu River, South Africa and to determine whether the largest lake in the region (Lake Nyamithi), which receives water from both rivers, would show a stronger resemblance to either of the two rivers. Aquatic invertebrate and water samples were collected from 2012 to 2018 over several seasons. The Usuthu River demonstrated a diverse and sensitive aquatic invertebrate community, emphasising its high conservation value. Despite maintaining relatively high aquatic invertebrate diversity, the Phongolo River demonstrated effects of anthropogenic impact, with more resilient taxa to changes in water quality and flow compared to the Usuthu River. Mismanagement and excessive water use may lead to the loss of any remaining sensitive aquatic invertebrate communities in this river. The presence of invasive molluscan species such as Physella acuta and Tarebia granifera in the Phongolo River and Lake Nyamithi also poses a threat to the aquatic invertebrate community in the system. These invasive species are currently absent from the Usuthu River although other invasive species, such as the Australian redclaw crayfish, are found in both river systems. Lake Nyamithi displayed a unique aquatic invertebrate community, distinct from both rivers and their floodplains. This study provides important baseline information on the Usuthu River’s aquatic invertebrates and emphasises the need to maintain adequate water flow in rivers and floodplains to protect biodiversity and sensitive species.

Ectotherms are expected to be particularly vulnerable to climate change driven increases in temperature. Understanding how populations adapt to novel thermal environments will be key for informing mitigation plans. We took advantage of threespine stickleback (Gasterosteus aculeatus) populations inhabiting adjacent geothermal (warm) and ambient (cold) habitats to test whether their evolutionary divergence was adaptive using field reciprocal transplant experiment. We found evidence for adaptive morphological divergence, as growth (length change) in the non-native habitat was found to relate to head, posterior and total body shape. Higher growth in fish transplanted to a non-native habitat was found to be associated with shape profiles closer to that of the native fish. The consequences of transplantation were asymmetric with cold sourced fish transplanted to the warm habitat suffering from lower survival rates and greater parasite prevalence than warm sourced fish transplanted to the cold habitat. We also found evidence for divergent shape allometries that related to growth. Our findings suggest that wild populations can adapt quickly to thermal conditions. However, immediate transitions to warmer conditions may be particularly difficult.

Geological events and historical environmental change can strongly affect the genetic structures and differentiation of fish populations. Although the central region of the Yunnan-Guizhou Plateau contains the highest concentration of rift-subsidence lakes in China, the effects of key geological events on the distributions and genetic structures of the regional fauna remain poorly understood. Fishes of the genus Sinocyclocheilus are endemic to the Yunnan-Guizhou Plateau, where they are found in karst landforms. As a result of environmental pollution and other human activities, Sinocyclocheilus populations have decreased sharply, and the genus is currently listed under Class II of the nationally protected animals classification in China. Examining the phylogeographic patterns of Sinocyclocheilus fishes can be useful for elucidating the spatio-temporal dynamics of their population size, dispersal history and extent of geographical isolation, thereby providing a theoretical basis for their protection. Here, we used Restriction Site Associated DNA Sequencing (RAD-seq) to investigate the evolution of Sinocyclocheilus fishes. Our analysis supports the endemicity of Sinocyclocheilus, and identifies the formation of Dianchi Lake and Fuxian Lake as key geological events shaping Sinocyclocheilus population structure. We estimate that the most recent common ancestor (MRCA) of Sinocyclocheilus fish occurred in the Central Yunnan Basin 3.75~3.11 Ma. It is the first time to prove that the altitude change has a great influence on the genetic variation among the populations of Sinocyclocheilus. We discuss the implications of our results for the protection and management of Sinocyclocheilus grahami and other cave fishes.

Habitat fragmentation can increase the chance of population bottlenecks and inbreeding, and may ultimately lead to reduced fitness and local extinction. Notelaea lloydii is a native olive species endemic to Australia and listed as vulnerable due to its restricted distribution. A recent molecular systematics study has revealed there might be some geographic structuring among the N. lloydii populations. Therefore, we undertook a genome wide Single Nucleotide Polymorphism (SNP) analysis to determine levels and patterns of genetic diversity, inbreeding and gene flow within and among N. lloydii populations in south-eastern Queensland (SE-QLD). Furthermore, as the reproductive phase of a plant’s life history has a profound influence on genetic diversity, life history reproductive traits were also studied. Our SNP analysis revealed low genetic diversity, inbreeding and significant genetic structuring even among proximate populations. Results of a flower and fruit bagging experiment in two consecutive seasons revealed that N. lloydii produced many flowers but only a few fruits survived to maturity. There were no differences in bagged and un-bagged flowering and fruiting rates and therefore, we conclude that the high fruit abortion rate was probably due to inbreeding depression and/or suboptimal conditions, rather than pollinator availability and insect attack. Overall, results of this study indicate that the populations of N. lloydii are small, inbred and genetically isolated and represent unique management units that require local conservation management due to ongoing threats associated with urbanisation.

Distyly, a floral dimorphism that promotes outcrossing, is controlled by a hemizygous genomic region known as the S-locus. Disruptions of genes within the S-locus are responsible for the loss of distyly and the emergence of homostyly, a floral monomorphism that favors selfing. Using whole genome resequencing data of distylous and homostylous individuals from populations of Primula vulgaris and leveraging high-quality reference genomes of Primula we tested, for the first time, predictions about the evolutionary consequences of transitions to selfing on S-locus genes. Our results confirm the presence of previously reported homostyle-specific, loss-of-function mutations in the exons of the S-locus gene CYPᵀ, while also revealing a previously undetected structural rearrangement in CYPᵀ associated with the shift to homostyly. Additionally, we discovered that the promoter region of CYPᵀ in distylous and homostylous individuals is identical, suggesting that down-regulation of CYPᵀ via mutations in its promoter region is not a cause of shift to homostyly. Furthermore, we found that hemizygosity leads to reduced genetic diversity and less efficient purifying selection in S-locus genes compared to genes outside the S-locus, and that the shift to homostyly further lowers genetic diversity, as expected for mating-system shifts. Finally, we tested, for the first time, long-standing theoretical models of changes in S-locus genotypes during early stages of the transition to homostyly, supporting the assumption that two (diploid) copies of the S-locus might reduce homostyle viability.

Honey bees play a vital role in providing essential ecosystem services and contributing to global agriculture. However, the potential effect of climate change on honey bee distribution is still not well understood. This study aims to identify the most influential bioclimatic and environmental variables, assess their impact on honey bee distribution, and predict future distribution. An ensemble modelling approach using the BIOMOD2 package in R was employed to develop three models, i.e., a climate-only model, an environment-only model, and a combined climate and environment model. The climate-only model focused on the bioclimatic factors: radiation of the wettest and driest quarters, and temperature seasonality. By utilizing bioclimatic data from 1990 to 2009, combined with observed honey bee presence and pseudo absence data, this model predicted honey bee distribution for two future time spans: 2020-2039 and 2060-2079. The climate-only model exhibited a True Skill Statistic (TSS) value of 0.85, underscoring the pivotal role of radiation and temperature seasonality in shaping honey bee distribution. The environment-only model incorporated environmental variables: proximity to regional ecosystems (floral resources), foliage projective cover, and elevation. This model demonstrated strong predictive performance, with a TSS of 0.88, emphasizing the significance of environmental variables in determining habitat suitability for honey bees. Remarkably, the combined model had a higher TSS of 0.96, indicating that the combination of climate and environmental variables enhances the model’s performance. Predictions for the 2060-2079 period revealed a concerning trend of 100% transition of highly suitable land into moderately (0.54%), marginally (17.56%) or not suitable areas (81.9%) for honey bees. These results emphasize the critical need for targeted conservation efforts and the implementation of policies aimed at safeguarding honey bees and the vital apiary industry.

Plant secondary metabolites (PSMs) are produced by plants to overcome environmental challenges, both biotic and abiotic. We were interested in characterizing how autumn seasonality in temperate and subtropical climates affects typical PSM production in comparison to herbivory. Herbivory is commonly measured from spring to summer when plants have high resource availability and are prioritizing growth and reproduction. However, autumn seasonality also challenges plants as they cope with limited resources and prepare survival for winter. This suggests a potential gap in knowledge on how autumn seasonality affects PSM production differently from herbivory. Using meta-analysis, we recorded production of 22 different PSM subgroups from 58 published papers to detect a typical response across all PSMs. We also compared production of five phenolic subgroups – hydroxybenzoic acids, flavan-3-ols, flavonols, hydrolysable tannins, and condensed tannins. We calculated effect sizes from herbivory studies (absence to presence) and temperate to subtropical seasonal studies (summer to autumn), while considering other variables (e.g., plant type, increase in time since herbivory, temperature, and precipitation). We did not detect a shared effect of herbivory or season on PSM production across all subgroups. However, we discovered herbivory having a positive effect on flavonol production and autumn seasonality having a positive effect on flavan-3-ol and condensed tannin production. We discuss how these responses might stem from three factors: 1. some PSMs are constitutively produced by plants in autumn whereas others are induced only following herbivory, 2. plants produce metabolites with higher costs only during seasons when other resources for growth and reproduction are less available, and 3. some PSM subgroups serve more than one function for plants and such functions can be season dependent. The outcome of our meta-analysis is that autumn seasonality changes PSM production differently from herbivory, and we see value in further investigating seasonality-herbivory interactions with plant chemical defense.

A document by Ellen Yasumiishi. Click on the document to view its contents.

The existence of adult sexual dimorphism is typically explained as a consequence of sexual selection, yet coevolutionary drivers of sexual dimorphism frequently remain untested. Here, I investigate the role of sexual dimorphism in host-parasite interactions of the brood parasitic diederik cuckoo, Chrysococcyx caprius. Female diederik cuckoos are more cryptic in appearance and pose a threat to the clutch, while male diederik cuckoos are conspicuous and not a direct threat. Specifically, I examine whether sexual dimorphism in diederik cuckoos provokes threat-level sensitive responses in Southern red bishop, Euplectes orix, hosts. I use experimentally simulated nest intrusions to test whether hosts have the capacity to differentially (i) detect, and/or (ii) discriminate between, male and female diederik cuckoos, relative to controls. Overall, I found no evidence that diederik cuckoos differ in detectability, since both sexes are comparable to controls in the probability and speed of host detection. Furthermore, neither male nor female hosts discriminate between sexually dimorphic diederik cuckoos when engaging in frontline nest defences. However, hosts that witnessed a male diederik cuckoo during the trial were more than twice as likely to reject odd eggs compared to those that saw a control. Moreover, hosts were more likely to reject experimental eggs when exposed to a male compared to a female diederik cuckoo: the reverse of a beneficial threat-level sensitive response. While the cryptic appearance of female diederik cuckoos does not differentially avoid detection by hosts, it does appear to provide the benefit of anonymity given the egg rejection costs of male-like appearance in the nest vicinity. These findings have implications for the evolution and maintenance of sexual dimorphism across the Cuculidae, and highlight the value of testing assumptions about the ecological drivers of sexual dimorphism.

Ecological stoichiometry is an important approach to understand the nutrient cycling and balance through the leaf-litter-soil system of Mongolian pine among different stand origins in desert regions. To reveal the variations in Mongolian pine carbon (C), nitrogen (N), and phosphorus (P) stoichiometry and stoichiometric homeostasis among different stand origins, we measured C, N, and P concentrations of leaves, litter, and soil, and analyzed the nutrient resorption efficiencies of leaves in differently aged plantations and natural forests from semi-arid and dry sub-humid regions. The results showed that (a) the stand origin had a significant effect on the C-N-P stoichiometry, and also significantly affected leaf N and P reabsorption efficiencies. Leaf N/P ratios indicated that Mongolian pine was co-limited by N and P in the NF, HB and HQ, and was mainly limited by P in MU. (2) With increasing stand age, C concentrations in the leaf-litter-soil system initially increased and then decreased, the N and P concentrations and reabsorption efficiencies in the leaf-litter-soil system were gradually increased. Overall, stand age had a significant effect on N concentrations, C/N and C/P ratios in the leaf-litter-soil system. (3) The C and N elements between the leaf-litter-soil system had a strong coupling relationship, and the P element between litter-soil had a strong coupling relationship. In addition, plantations exhibited greater N/P homeostasis than natural forests, and N/P exhibited greater homeostasis than N and P alone, which may be a nutrient utilization strategy for forests to alleviate N or P limitation. (4) Environmental factors have a significant influence on C-N-P stoichiometry in the leaf-litter-soil system, the most important soil properties and meteorological factors being soil water content and precipitation, respectively. These results will be essential to provide guidance for plantation restoration and management in desert regions.

Plant reproductive ecology is one of the research hotspots in ecology. With the increasing attention paid to the conservation of plant diversity, the research on reproductive characteristics and flowering biological characteristics of more species has attracted more attention. However, plant reproduction is affected by multiple interacting factors such as pollen limitation and resource availability. Vitex negundo var. heterophylla (Franch.) Rehder (Lamiaceae) is a significant species for water and soil conservation. Previous studies have revealed its mating system by the biological characteristics of flowering and SSR markers, but its reproductive strategies remain to be further studied. We evaluated reproductive success through artificial pollination to explore the reproductive characteristics of V. negundo var. heterophylla for the first time. From the results of fruit set, there is a mixed mating system dominated by outcrossing in V. negundo var. heterophylla accompanied by self-compatibility, and it cannot carry out autonomous selfing. Our data shows the pollinator-mediated interaction in the success of reproduction, whereas the effect of anemophily is very weak. And the seed germination rate of inbred line progenies was lower than that of hybrid progenies, which is suspected to be caused by inbreeding depression. The research will provide scientific information for the protection and conservation of V. negundo var. heterophylla from the point of view of reproduction. In sum, the results are necessary to protect animal vectors in the background of insect decline.

The effect of mixing litter on decomposition has received considerable attention in terrestrial and aquatic (but rarely in both) ecosystems, with a striking lack of consensus in the obtained results. We studied the decomposition of a mixture of poplar and alder in three terrestrial:aquatic exposures to determine (1) if the effect of mixing litter on mass loss, associated decomposers and detritivores differs between the stream (fully aquatic exposure) and when litter is exposed to a period of terrestrial exposure prior to immersion and (2) the global effect of the mixture across exposure scenarios. The effect of the mixture was additive on mass loss and synergistic on decomposers and detritivores across exposure scenarios. Within scenarios, mass loss and decomposers showed synergistic effects only in the fully aquatic exposure, detritivores showed synergistic effects only when the period of terrestrial was shorter than the period of aquatic exposure, and when the period of terrestrial was equal to the period of aquatic exposure the effect of the mixture was additive on mass loss, decomposers, and detritivores. The species-specific effects also differed among exposure scenarios. Alder affected poplar only when there was a period of terrestrial exposure, with increased sporulation rates and fungal richness in exposure 25:75, and increased mass loss in exposure 50:50. Poplar affected alder only under fully aquatic exposure, with increased mass loss. In conclusion, the synergistic effects of the mixture changed with a period of terrestrial exposure prior to immersion. These results provide a cross-boundary perspective on the effect of mixing litter, showing a legacy effect of exposure to terrestrial decomposition on the fate of plant litter in aquatic ecosystems and highlighting the importance of assessing the effect of mixing litter on the associated biota and not only on mass loss.

Insect herbivores, such as lepidopteran larvae, often have close evolutionary relationships with their host plants, with which they may be locked in an evolutionary arms race. Larval grouping behaviour may be one behavioural adaptation that improves host plant feeding, but aggregation also comes with costs, such as higher competition and limited resource access. Here, we use the Heliconiini butterfly tribe to explore the impact of host plant traits on the evolution of larval gregariousness. Heliconiini almost exclusively utilise species from the Passifloraceae as larval host plants. Passifloraceae display incredible diversity of form, leaf shape and a range of anti-herbivore defences, suggesting they are locked in an arms race with Heliconiini larvae. By analysing larval social behaviour as both a binary (solitary or gregarious) and categorical (increasing larval group size) trait, we revisit the multiple origins of larval gregariousness across Heliconiini. We investigate whether host habitat, leaf defences and leaf size are important drivers of, or constraints on, larval gregariousness. Whereas our data do not reveal links between larval gregariousness and the host plant traits included in this study, we do find an interaction between larval host specialisation and behaviour, revealing gregarious larvae to be more likely to feed on a narrower range of host plant species than solitary larvae. We also find evidence that this increased specialisation typically precedes the evolutionary transition to gregarious behaviour. The comparatively greater host specialisation of gregarious larvae suggests that there are specific morphological and/or ecological features of their host plants that favour this behaviour.

1. Cyanobacterial blooms in freshwater sources are a global concern, and gaining insight into their causes is crucial for effective resource management and control. 2. In this study, we present a computational framework for the causal analysis of cyanobacterial harmful algal blooms (cyanoHABs) in Lake Kinneret. Our framework integrates Convergence Cross Mapping (CCM) and Extended CCM (ECCM) causal networks with Bayesian Network (BN) models. 3. The constructed CCM - ECCM causal networks and BN models unveil significant interactions among factors influencing cyanoHAB formation. These interactions have been validated by domain experts and supported by evidence from peer-reviewed publications. Our findings suggest that M. flos-aquae levels are influenced not only by community structure but also by nitrate, nitrite, ammonium, phosphate, oxygen, and temperature levels in the weeks preceding bloom occurrences. 4. We have demonstrated a non-parametric computational framework for the causal analysis of a multivariate ecosystem. Our framework offers a more comprehensive understanding of the underlying mechanisms driving M. flos-aquae in Lake Kinneret. It captures complex interactions and provides an explainable prediction model. By considering causal relationships, temporal dynamics, and joint probabilities of environmental factors, the proposed framework enhances our understanding of cyanoHABs in Lake Kinneret.