Wild bees form diverse communities that pollinate plants in both native and agricultural ecosystems making them both ecologically and economically important. The growing evidence of bee declines has sparked increased interest in monitoring bee community and population dynamics using standardized methods. Here, we studied the dynamics of bee biodiversity within and across years by monitoring wild bees adjacent to four apple orchard locations in Southern Pennsylvania, USA. We collected bees using passive Blue Vane traps continuously from April to October for six years amassing over 26,000 bees representing 144 species. We quantified total abundance, richness, diversity, composition, and phylogenetic structure. There were large seasonal changes in all measures of biodiversity with month explaining an average of 72% of the variation in our models. Changes over time were less dramatic with years explaining an average of 44% of the variation in biodiversity metrics. We found declines in all measures of biodiversity especially in the last 3 years. Analyses of population trends over time for the 40 most abundant species indicate that about one third of species showed at least some evidence for declines in abundance. Bee family explained variation in species-level seasonal patterns but we found no consistent family-level patterns in declines, though bumble bees and sweat bees were groups that declined the most. Overall, our results show that season-wide standardized sampling across multiple years can reveal nuanced patterns in bee biodiversity, phenological patterns of bees, and population trends over time of many co-occurring species. These datasets could be used to quantify the relative effects that different aspects of environmental change have on bee communities and to help prioritize conservation efforts.
The response of communities to climate change is expected to vary among feeding guilds. To evaluate the response of guilds to environmental factors without considering the taxonomic specificities, it is useful to examine Aculeata bees and wasps, which consist of closely related taxa including different guilds, pollinators, predators, and parasitoids. In this study, we evaluated changes in species diversity (SD) and functional traits of each feeding guild along an elevational gradient in a boreal forest in northern Japan. We used yellow pan traps to collect Aculeata bees and wasps at 200–1600 m above sea level. We investigated six functional traits (trophic level, flight duration, body size, elevational range, nesting position, and soil dependency) and the horizontal distribution of the species. The SD of all Aculeata predators and parasitoids decreased with an increase in elevation; however, the SD of pollinators did not show any specific trend. Although the functional trait composition of all Aculeata species did not show any trend, that of each feeding guild responded to elevation in different ways. Pollinators increased in body size and showed a decrease in flight duration with increasing elevation, suggesting that tolerance and seasonal escape from physical stress at high elevations are important for shaping pollinator communities. Predators showed increased elevational range and above-ground nesting species with increasing elevation, suggesting that the ability to live in a wider range of environments and avoid unsuitable soil environments at high elevations might be important. Parasitoids changed their hosts and variable traits with increasing elevation, suggesting that brood parasitoids have difficulty in surviving at high elevation. The traits for each guild responded in different ways, even if they were dominated by the same environmental factors. Differences in the response of functional traits would produce different patterns of community formation in different guilds during further climate change.
Soil microorganisms are crucial contributors to the function of permafrost ecosystems, as well as the regulation of biogeochemical cycles. However, little is known about the distribution patterns and drivers of high-latitude permafrost microbial communities subject to climate change and human activities. In this study, the vertical distribution patterns of soil bacterial communities in the Greater Khingan Mountain permafrost region were systematically analyzed via Illumina Miseq high-throughput sequencing. Bacterial alpha diversity varied significantly at different soil depths, and the bacterial diversity and richness in the active layer were significantly higher than in the permafrost layer. The relative abundance of the dominant phyla Chloroflexi (17.92%–52.79%) and Actinobacteria (6.34%–34.52%) was significantly higher in the permafrost layer than in the active layer, whereas that of Acidobacteria (4.98%–38.82%) exhibited the opposite trend, and the abundance of Proteobacteria (2.49%–22.51%) generally decreased with depth. More importantly, the abundance of microorganisms linked to human infectious diseases was significantly higher in the permafrost layer according to Tax4Fun prediction analysis. Redundancy analysis (RDA) showed that NH4+-N, TOC and TP were major factors affecting the bacterial community composition. Collectively, our findings provide insights into the soil bacteria at different depths in high-latitude permafrost regions, as well as their vertical distribution patterns and major environmental drivers, which is key to grasping the response of cold region ecosystem processes to global climate changes.
Association is the basic unit of plant community classification. Exploring the distribution of plant associations can help improve the understanding of biodiversity conservation. Different associations depend on different habitats. Studying the association level is significant for ecological restoration, regional ecological protection, regulating the ecological balance, and maintaining biodiversity. However, previous studies have focused only on the suitable distribution areas of species and not on the distribution of plant associations. Larix gmelinii is a sensitive and abundant species spread in the southern margin of Eurasian boreal forests, and its distribution is closely related to permafrost. In this study, 420 original plots of L. gmelinii forests were investigated. We used Maxent model and ArcGIS software to project the potential geographical distribution of L. gmelinii associations in the future (by 2050 and 2070) according to the climate scenarios RCP 2.6, RCP 4.5, and RCP 8.5. The causes for the changes in spatial distribution were analyzed using multinomial logistic regression analysis. The results revealed that temperature is the most important factor affecting the distribution of L. gmelinii forests and most of its associations under different climate scenarios. Further, the suitable areas for each association type are shrinking by varying degrees, especially due to habitat loss at high altitudes in special terrains. For different L. gmelinii associations, management measures should also be different based on the different site conditions, composition structure, growth, development, and renewal succession trends. Furthermore, subsequent research should consider data on biological factors to obtain more accurate prediction results.
The rapid urbanization has caused changes in climate and environment and threatened the ecosystem with multiple risks. The ecological service capacity has shown a downward trend accordingly. It is significant to explore the spatio-temporal evolution of land use and ecological service value in mountainous counties at small scales, as it coordinates economic growth and ecological protection, and promotes sustainable and high-quality development. Based on the SD-PLUS model, taking Qianshan city as an example, the study simulated three scenarios of land use change: ecological protection, coordinated development, and economic priority, and studied the impacts of land use change on the value of ecosystem services. Results showed that: ① Under the three scenarios, the construction land in the study area increased significantly, the forest and water area have a decreasing trend, and the scale of gardens has partly increased. ② Construction land expands in clusters in the urban built-up areas and dots in mountainous areas; land use changes are primarily affected by roads, followed by areas where artificial facilities are relatively sparse, and DEM has the greatest impact on land use changes. ③ The overall ecosystem service value shows a downward trend, with the comprehensive coordination type dropping the least (8.79%). The value distribution changes little at space scale, and different regions demonstrate different degrees of changes. From the perspective of value type, the service values of climate regulation and water conservation are significantly reduced, while that of food production is relatively stable; and from the perspective of various lands with their ecological service values, cultivated land and forest remain stable. The study results can provide technical ideas for the coordinated economic development and ecological protection of mountainous cities, and boost the implementation of green development.
The horned gall aphid Schlechtendalia chinensis, is an economically important insect that induces galls valuable for medicinal and chemical industries. S. chinensis manipulates its host plant to form well-organized horned galls during feeding. So far, more than twenty aphid genomes have been reported; however, all of those are derived from free-living aphids. Here we generated a high-quality genome assembly of S. chinensis, representing the first genome sequence of a galling aphid. The final genome assembly was 280.43 Mb, with 97% of the assembled sequences anchored into thirteen chromosomes. S. chinensis presents the smallest aphid genome size among available aphid genomes to date. The contig and scaffold N50 values were 3.39 Mb and 20.58 Mb, respectively. The assembly included 96.4% of conserved arthropod and 97.8% of conserved Hemiptera single-copy orthologous genes based on BUSCO analysis. A total of 13,437 protein-coding genes were predicted. Phylogenomic analysis showed that S. chinensis formed a single clade between the Eriosoma lanigerum clade and the Aphidini+Macrosiphini aphid clades. In addition, salivary proteins were found to be differentially expressed when S. chinensis underwent host alternation, indicating their potential roles in gall formation and plant defense suppression. A total of 36 cytochrome P450 genes were identified in S. chinensis, considerably fewer compared to other aphids, probably due to its small host plant range. The high-quality S. chinensis genome assembly and annotation provide an essential genetic background for future studies to reveal the mechanism of gall formation and to explore the interaction between aphids and their host plants.
Metabarcoding has improved the way we understand plants within our environment, from their ecology and conservation to invasive species management. The notion of identifying plant taxa within environmental samples relies on the ability to match unknown sequences to known reference libraries. Without comprehensive reference databases, species can go undetected or be incorrectly assigned, leading to false positive and negative detections. To improve our ability to generate reference sequence databases we developed a targeted capture approach using the OZBaits_CP V1.0 set, designed to capture chloroplast gene regions across the entirety of flowering plant diversity. We focused on generating a reference database for coastal temperate plant species given the lack of reference sequences for these taxa. Our approach was successful across all specimens with a target gene recovery rate of 92% which was achieved in a single assay (i.e., samples were pooled), thus making this approach much faster and more efficient than standard barcoding. Further testing of this database highlighted 80% of all samples could be discriminated to family level across all gene regions with some genes achieving greater resolution than others – which was also dependant on the taxon of interest. Thus, we demonstrate the importance of generating reference sequences across multiple chloroplast gene regions as no single loci is sufficient to discriminate across all plant groups. The targeted capture approach outlined in this study provides a way forward to achieve this.
In long-lived species, reproductive skipping is a common strategy whereby sexually mature animals skip a breeding season, potentially reducing population growth. This may be an adaptive decision to protect survival, or a non-adaptive decision driven by individual-specific constraints. Understanding the presence and drivers of this behaviour is key to effective population management, yet in many species such as the endangered African penguin (Spheniscus demersus), these factors remain unknown. This study uses multistate mark-recapture methods to estimate African penguin survival and breeding probabilities at two colonies between 2013 and 2020. Overall, survival was higher at Stony Point (0.82) than Robben Island (0.77). Inter-colony differences were linked to food availability; under decreasing sardine (Sardinops sagax) abundance, survival decreased at Robben Island and increased at Stony Point. Additionally, reproductive skipping was evident across both colonies; at Robben Island ~22% of breeding individuals skipped reproduction each year, versus ~10% at Stony Point. Penguins skipping reproduction had a lower probability of future breeding than breeding individuals; this lack of adaptive benefit suggests reproductive skipping is driven by individual-specific constraints. Lower survival and breeding propensity at Robben Island places this colony in greater need of conservation action. However, further research on the drivers of inter-colony differences is needed.
Ecological restoration of former agricultural land can improve soil condition, recover native vegetation, and provide fauna habitat. However, restoration benefits are often associated with time lags, as many attributes, such as leaf litter and coarse woody debris, need time to accumulate. Here we experimentally tested whether adding fine and coarse woody debris to a decade-old restoration sites can accelerate restoration benefits. We used a Multi-site Before-After / Control-Impact design to test the effects on 30 response variables over a period of two years, including those describing soil physical and biochemical properties, herbaceous vegetation and ant communities. We analysed the data using linear mixed-effect models and perMANOVAs. Of the 30 response variables, a significant effect of mulch or log additions was found for just four variables: volumetric water content, decomposition of tea leaves, native herbaceous species cover and species richness of opportunistic ants. Mulch addition had a positive effect on soil moisture when compared to controls but suppressed growth of native (but not exotic) herbaceous plants. Whilst other soil properties such as organic matter and dissolved organic carbon showed a positive response to mulch addition, the effect was not statistically significant. On plots with log additions, decomposition rates of tea leaves decreased, and species richness of opportunistic ants increased. However, we found no effect on total species richness and abundance of other ant functional groups. The benefit of mulch to soil moisture was offset by its disbenefit to native herbs in our study. Logs increased species richness of opportunistic ants, but given time, may provide habitat for cryptic species. Indeed, benefits to other soil biophysical properties, vegetation and ant fauna may require longer timeframes to be detected. Further research is needed to determine whether the type, quantity and context of mulch and log additions may improve restoration outcomes.
Environmental temperature is a key driver of malaria transmission dynamics. Using detailed temperature records from four sites (1800-3200m) in the western Himalaya, we model how temperature regulates parasite development rate (the inverse of the extrinsic incubation period, EIP) in the wild. Using a Briére parametrization of the EIP, combined with Bayesian parameter inference, we study the thermal limits of transmission for avian (P. relictum) and human Plasmodium parasites (P. vivax and P. falciparum) as well as for two malaria-like avian parasites, Haemoproteus and Leucocytozoon. We demonstrate that temperature conditions can substantially alter the incubation period of parasites at high elevation sites (2600-3200m) leading to restricted parasite development or long transmission windows. We then compare estimates of EIP based on measures of mean temperature versus hourly temperatures to show that EIP days vary in cold versus warm environments. We found that human Plasmodium parasites experience a limited transmission window at 2600m. In contrast, for avian Plasmodium transmission was not possible between September to March at 2600m. In addition, temperature conditions suitable for both Haemoproteus and Leucocytozoon transmission were obtained from June to August and in April, at 2600m. Finally, we use temperature projections from a suite of climate models to predict that by 2040, high elevation sites (~ 2600 m) will have a temperature range conducive for malaria transmission, albeit with a limited transmission window. Our study highlights the importance of accounting for fine-scale thermal effects in the expansion of the range of the malaria parasite with global climate change.
Climate change and fisheries exploitation are dramatically changing the species composition, abundances, and size spectra of fish communities. We explore whether variation in abundance-size spectra, a widely studied ecosystem feature, is influenced by a critical parameter thought to govern the shape of size-structured ecosystems—the relationship between the sizes of predators and their prey (predator-prey mass ratios, or PPMRs). PPMR estimates are lacking for vast numbers of fish species, including at the broader trophic guild scale. Using measurements of 8,128 prey items in gut contents of 97 reef fish species, we established PPMRs for four major trophic guilds (piscivores, invertivores, planktivores and herbivores) using linear mixed effects models. To assess theoretical predictions that higher mean community-level PPMR leads to shallower size spectrum slopes, we compared observations of mean community-level PPMR with size spectrum slopes for coastal reef sites distributed around Australia. PPMRs of individual fishes were remarkably high (median ~71,000), with significant variation between different trophic guilds (~890 for piscivores; ~83,000 for planktivores), and ~8,700 for whole communities. Community-level PPMRs were positively related to size spectrum slopes, broadly consistent with theory, however, this pattern was also influenced by the latitudinal temperature gradient. Tropical reefs showed a stronger relationship between community-level PPMRs and community size spectrum slopes than temperate reefs. The extent that these patterns apply outside Australia, and consequences for community structure and dynamics, are key areas for future investigation.
The South American temperate forests have been subjected to drastic past topographic and climatic changes during the Pliocene – Pleistocene linked to Andean orogeny and glacial cycles. These changes are common drivers of genetic structure and adaptation process. Embothrium coccineum, a member of the Proteaceae family and an emblematic tree of the South American temperate forest with a distribution spanning 20° of latitude, has been strongly affected by these topographic and climatic changes. Previous studies have shown that the species presents a marked genetic structure with distinct ecotypes described; yet, little is known about their adaptive genetic responses. The main goal of this study was to investigate the effects of historical and contemporary landscape features affecting the genetic diversity and connectivity of E. coccineum throughout its natural distribution. Using more than 2000 SNPs, two genetic groups (North and Center-South) that have diverged some 2.8 million years ago were observed. The level of genetic structure was higher between populations within the North genetic group than within the Center-South group. We propose that these contrasting patterns of genetic structure are related to differences in pollinator’s assemblage and evolutionary histories between genetic groups. Moreover, we observed the existence a strong patter of isolation by environment in E. coccineum, suggesting that selection could have leaded to adaptive divergence among localities. We propose that, within the Chilean temperate forest, the patterns of genetic variation in E. coccineum reflect both a Quaternary phylogenetic imprint and the impact of selection to the strong environmental gradient.
Nutrient composition and food availability determine food choices and foraging strategies of animals. Altitude affects species distribution and food availability, whereas primate food needs increase with body size. However, the mechanism of food selection in large primates at low altitudes requires further investigation. As the largest species in the genus Macaca, the Tibetan macaque (Macaca thibetana) has sophisticated foraging strategies. In this study, we researched a group of 29 wild Tibetan macaques (Tianhu Mountain Group) that live in a low-altitude area around Mt. Huangshan, Anhui Province, China. We used instantaneous and scan sampling for observing the foraging behavior of these macaques from September 2020 to August 2021. We recorded the dietary composition and food availability, compared the nutrient content of staple food and non-food items, and analyzed the role of key nutrients in food selection. We found that Tibetan macaques forage on 111 plants belonging to 93 genera and 55 families. The food types included 52.5% fruits, 17.0% mature leaves, 6.3% young leaves, 1.9% stems, 4.5% flowers, 14.4% bamboo shoots, 1.3% tender shoots, and 2.1% other. Tibetan macaques forage for a maximum total of 76 plant species during spring. However, dietary diversity was highest during summer (H’=3.052). Monthly fruit consumption was positively correlated with food availability. Staple foods are lower in fiber and tannins than non-foods. In addition, there was a positive correlation between the time spent foraging for specific foods and sugar content of the food. The results showed that the plant species and food types fed by Tibetan macaques were diverse, and their foraging strategies varied seasonally. Our findings confirm the effect of nutrients on food choice in Tibetan macaques, highlighting the importance of sugar in their food choices and suggesting that the foraging behavior of Tibetan macaques is highly flexible and adaptive.
Human disturbance directly affects animal populations but indirect effects of disturbance on species behaviors are less well understood. Camera traps provide an opportunity to investigate variation in animal behaviors across gradients of disturbance. We used camera trap data to test predictions about predator-sensitive behavior in three ungulate species (caribou Rangifer tarandus; white-tailed deer, Odocoileus virginianus; moose, Alces alces) across two boreal forest landscapes varying in disturbance. We quantified behavior as the number of camera trap photos per detection event and tested its relationship to predation risk between a landscape with greater industrial disturbance and predator abundance (Algar) and a “control” landscape with lower human and predator activity (Richardson). We also assessed the influence of predation risk and habitat on behavior across camera sites within the disturbed Algar landscape. We predicted that animals in areas with greater predation risk (more wolf activity, less cover) would travel faster and generate fewer photos per event, while animals in areas with less predation risk would linger (rest, forage), generating more photos per event. Consistent with predictions, caribou and moose had more photos per event in the landscape where predation risk was reduced. Within the disturbed landscape, no prey species showed a significant behavioral response to wolf activity, but the number of photos per event decreased for white-tailed deer with increasing line of sight (m) along seismic lines (i.e. decreasing visual cover), consistent with a predator-sensitive response. The presence of juveniles was associated with shorter behavioral events for caribou and moose, suggesting greater predator sensitivity for females with calves. Only moose demonstrated a positive association with vegetation productivity (NDVI), suggesting that for other species influences of forage availability were generally weaker than those from predation risk. Behavioral insights can be gleaned from camera trap surveys and provide information about animal responses to predation risk and the indirect impacts of human disturbances.
Species distributions are one of the fundamental factors needed for understanding and conserving wildlife. While the IUCN Red List of Threatened Species is the primary applied reference for biodiversity conservation, limitations in data availability and analyses of the distributions of some species may limit accurate threat classification assessments and conservation recommendations. Improving the accuracy of species distributions in light of growing data and analytical methods is a key step to increasing the efficacy of the Red List. In this study, we reassessed the distribution of takin (Budorcas taxicolor tibetana), a large ungulate in Sichuan Province, southwest China , classified by the IUCN as vulnerable. Using species distribution models and reported habitat requirements, we updated the takin distribution map. Our updated distribution range in the study area (79,449km2) was 61.31% of current distribution range (CDR) on the IUCN red list. This reduction was in large part due to the inclusion in the CDR of substantial areas of lowland plains, high human disturbance, and non-forest habitat, which provide no suitable habitat for takin. According to our results, suitable takin habitat covered 18.97% of the CDR, suggesting a substantially over-estimated distribution. However, there are high proportions of habitat (40%) still covered by the nature reserve network, indicating the importance of protected areas (PAs) in conservation threaten species. We recommend that experts apply the basic approach presented herein to update the Red List distributions for more species to increase the accuracy of assessments and resulting conservation applications.
Submerged macrophytes play a key role in maintaining a clear-water phase and promoting biodiversity in shallow aquatic ecosystems. Since their abundance has declined globally due to anthropogenic activities, it is important to include them in aquatic ecosystem restoration programs. That macrophytes establish in early spring is crucial for maintaining the macrophyte communities for the remainder of the year. However, factors affecting this early establishment of submerged macrophytes have not been fully explored yet. Here, we conducted an outdoor experiment from winter to early spring using the submerged macrophytes Potamogeton crispus and Vallisneria spinulosa to study the effects of shading, nutrient loading, snail herbivory (Radix swinhoei) and their interactions on the early growth and stoichiometric characteristics of macrophytes. The results show that the effects strongly depend on macrophyte species. Biomass and number of shoots of P. crispus decreased, and internode length increased during low light conditions, but were not affected by nutrient loading. P. crispus shoot biomass and number showed hump-shaped responses to increased snail biomass under full light. In contrast, the biomass of the plant linearly decreased with snail biomass under low light. This indicates an interaction of light with snail herbivory. Since snails prefer grazing on periphyton over macrophytes, a low density of snails promoted growth of P. crispus by removing periphyton competition, while herbivory on the macrophyte increased during a high density of snails. The growth of V. spinulosa was not affected by any of the factors, probably because of growth limitation by low temperature. Our study demonstrates that the interaction of light with snail herbivory may affect establishment and growth of submerged macrophytes in early spring. Macrophyte restoration projects may thus benefit from lowering water levels to increase light availability and making smart use of cold-adapted herbivores to reduce light competition with periphyton.
Adaptive habitat construction is a process by which individuals alter their environment so as to increase their (inclusive) fitness. Such alterations are a subset of the myriad ways that individuals condition their environment. We present an individual-based model of habitat construction to explore what factors might favor selection when the benefits of environmental alterations are shared by individuals of the same species. Our results confirm the predictions of inclusive fitness and group selection theory and expectations based on previous models that construction will be more favored when its benefits are more likely to be directed to self or near kin. We found that temporal variation had no effect on the evolution of construction. For spatial heterogeneity, construction was disfavored when the spatial pattern of movement did not match the spatial pattern of environmental heterogeneity, especially when there was spatial heterogeneity in the optimal amount of construction. Under those conditions, very strong selection was necessary to favor genetic differentiation of construction propensity among demes. We put forth a constitutive theory for the evolution of adaptive habitat construction that unifies our model with previous verbal and quantitative models into a formal conceptual framework.
Aims Although minor climatic forest refuges were important as key areas for the long-term persistence of species and genetic diversity, and can again function as refuges during present and future climatic changes, they have received little attention in sub-Saharan Africa. The objectives in this paper were to assess the Togolese montane riparian forests as minor sub-Saharan forest refugia, examine the contribution of minor sub-Saharan forest refugia to the larger forest refugia using the Togolese montane riparian forests as a model, and discuss the implication of these results for biogeography and forest biodiversity conservation in sub-Saharan tropical Africa based on the floristic approach. Location Southwest Togo, West Africa, sub-Saharan Upper Guinea Region Methods Floristic data were collected across Togolese mountain riparian forests through an intensive botanical inventory using the survey approach (n=198; 50×10 m2). A comparative analysis was performed on the basis of floristic criteria and attributes related to climatic forest refuges. Results According to floristic attributes, the riparian forests of the subhumid Togolese mountains were important minor refuges for rainforests during Pleistocene warming. They share about 60% of their current species richness (868 species) with the large sub-Saharan forest refuges. Main conclusions The floristic data were similar to that of previous studies focusing on the forest refugia around the DG and elsewhere worldwide. However, they seem to be incompatible with the ideas that the DG forest flora may be essentially a relic of the early Holocene, when the geographical distribution of the Guinean-Congolian forest was maximum. Efforts to maintain maximum species diversity in sub-Saharan Africa should therefore pay particular attention to the conservation of minor forest refugia. This study asks important questions about the patterns of disjunction, which should be focused on in further studies. Keywords Tropical biodiversity, Forest refuges, Floristic approach, Dahomey Gap (DG), Togolese Mountain, Vegetation