Specific Habitat Research Articles

Threshold responses and relationships between waterbird distribution and habitat factors at Shengjin Lake, China

The wintering period is an essential part of the annual life history of waterbirds. The environmental conditions of habitats in winter directly affect the abundance and physical condition of waterbirds. Therefore, it is important to study the relationship between waterbird abundance and habitat factors. In this study, we conducted significance and threshold analyses between habitat factors and the waterbird community at Shengjin Lake, a Ramsar Site in China, using Redundancy Analysis (RDA), Spearman Correlation Analysis, and Threshold Indicator Taxa Analysis (TITAN). The results indicate that seven environmental variables significantly affected the abundance of waterbird communities, that is, fractional vegetation cover, degree of receding water, grassland area, mudflat area, shallow water area, deep water area, and distance to reeds. Waterbird communities exhibited significant threshold responses to all seven factors. The number of species significantly responding to different habitat factors varied among waterbird communities, with the highest number of species (15) responding to distance to reeds. Except for the deep water area and distance to reeds, waterbirds showed higher positive than negative thresholds for the remaining five factors. Different groups of waterbirds influenced the threshold responses of waterbird communities to habitat factors, and there were variations in how each waterbird group responded to these factors. The results of this study highlight the importance of habitat type, water recession degree, and shelter conditions in waterbird habitat selection. Minor differences in habitat structure can influence waterbird habitat preferences. Therefore, wetland management at Shengjin Lake should consider the specific habitat needs of different waterbird species.

An ecotype-specific effect of osmopriming and melatonin during salt stress in Arabidopsis thaliana

BackgroundNatural populations of Arabidopsis thaliana exhibit phenotypic variations in specific environments and growth conditions. However, this variation has not been explored after seed osmopriming treatments. The natural variation in biomass production and root system architecture (RSA) was investigated across the Arabidopsis thaliana core collection in response to the pre-sawing seed treatments by osmopriming, with and without melatonin (Mel). The goal was to identify and characterize physiologically contrasting ecotypes.ResultsVariability in RSA parameters in response to PEG-6000 seed osmopriming with and without Mel was observed across Arabidopsis thaliana ecotypes with especially positive impact of Mel addition under both control and 100 mM NaCl stress conditions. Two ecotypes, Can-0 and Kn-0, exhibited contrasted root phenotypes: seed osmopriming with and without Mel reduced the root growth of Can-0 plants while enhancing it in Kn-0 ones under both control and salt stress conditions. To understand the stress responses in these two ecotypes, main stress markers as well as physiological analyses were assessed in shoots and roots. Although the effect of Mel addition was evident in both ecotypes, its protective effect was more pronounced in Kn-0. Antioxidant enzymes were induced by osmopriming with Mel in both ecotypes, but Kn-0 was characterized by a higher responsiveness, especially in the activities of peroxidases in roots. Kn-0 plants experienced lower oxidative stress, and salt-induced ROS accumulation was reduced by osmopriming with Mel. In contrast, Can-0 exhibited lower enzyme activities but the accumulation of proline in its organs was particularly high. In both ecotypes, a greater response of antioxidant enzymes and proline accumulation was observed compared to mechanisms involving the reduction of Na+ content and prevention of K+ efflux.ConclusionsIn contrast to Can-0, Kn-0 plants grown from seeds osmoprimed with and without Mel displayed a lower root sensitivity to NaCl-induced oxidative stress. The opposite root growth patterns, enhanced by osmopriming treatments might result from different protective mechanisms employed by these two ecotypes which in turn result from adaptive strategies proper to specific habitats from which Can-0 and Kn-0 originate. The isolation of contrasting phenotypes paves the way for the identification of genetic factors affecting osmopriming efficiency.

Museum genomics provide insight into the extinction of a specialist North American warbler species

Museum genomics provide an opportunity to investigate population demographics of extinct species, especially valuable when research prior to extinction was minimal. The Bachman’s warbler (Vermivora bachmanii) is hypothesized to have gone extinct due to loss of its specialized habitat. However, little is known about other potential contributing factors such as natural rarity or changes to connectivity following habitat fragmentation. We examined mitochondrial DNA (mtDNA) and genome-wide SNPs using specimens collected from breeding and migration sites across the range of the Bachman’s warbler. We found no signals of strong population structuring across the breeding range of Bachman’s warblers in both mtDNA and genome-wide SNPs. Thus, long-term population isolation did not appear to be a significant contributor to the extinction of the Bachman’s warbler. Instead, our findings support the theory that Bachman’s warblers underwent a rapid decline likely driven by habitat destruction, which may have been exacerbated by the natural rarity, habitat specificity and low genetic diversity of the species.

Habitat suitability modelling to predict the distribution of deep coral ecosystems: The case of Linosa Island (southern Mediterranean Sea, Italy)

In areas with limited field data, predictive habitat mapping is a valuable method for elucidating species-environment relationships and enhancing our knowledge of the spatial distribution and complexity of benthic habitats. Species distribution models (SDMs) can be an important tool to support in science-based ecosystem management. The availability of direct observations of mesophotic species, including gorgonians and black corals, during costly surveys is generally limited. Therefore, predicting the distribution of mesophotic species in relation to key physical parameters of the seafloor would help improving conservation strategies in existing and new Marine Protected Areas (MPAs). This study aims to assess the distribution of gorgonians and black corals off Linosa Island, in the Strait of Sicily, a biogeographic boundary area between the western and eastern Mediterranean. The volcanic island of Linosa represents a small, naturally preserved area, with very limited human pressure, hosting rich marine benthic biodiversity on its wide submarine portions. Distribution of the most common coral species off Linosa Island was modelled under an SDM framework, relying on direct observations collected during two research cruises in 2016 and 2017 and a series of terrain parameters acquired through geophysical techniques. We used the so-called “ensemble of small models” approach to calibrate SDMs, which achieved fair-to-excellent results (AUC >0.7). In addition to identifying depth as the primary factor influencing coral distribution, our study also highlighted ruggedness as a significant terrain variable. Specifically, the depth range of 110–230 m emerged as the critical parameter determining habitat suitability for all modelled species, also highlighting peculiar and specie–specific habitat requirements.

Climate Change Threatens Barringtonia racemosa: Conservation Insights from a MaxEnt Model

Barringtonia racemosa (L.) Spreng. (Lecythidaceae), a crucial species in mangrove ecosystems, is facing endangerment primarily due to habitat loss. To address this issue, research is imperative to identify suitable conservation habitats for the endangered B. racemosa within mangrove ecosystems. The utilization of the optimized Maximum Entropy (MaxEnt) model has been instrumental in predicting potential suitable regions based on global distribution points and environmental variables under current and future climates conditions. The study revealed that the potential distribution area of B. racemosa closely aligns with its existing range with an Area Under the Curve (AUC) greater than 0.95. The Jackknife, AUC, percent contribution (PC), and permutation importance (PI) tests were employed alongside the optimized MaxEnt model to examine the influence of environmental variables on the distribution of B. racemosa. The primary factors identified as significant predictors of B. racemosa distribution included the average temperature of the ocean surface (Temperature), average salinity of the ocean surface (Salinity), precipitation of the warmest quarter (Bio18), precipitation of the driest month (Bio14), seasonal variation coefficient of temperature (Bio4), and isothermality (Bio3). Currently, the habitat range of B. racemosa is predominantly found in tropical and subtropical coastal regions near the equator. The total suitable habitat area measures 246.03 km2, with high, medium, low, and unsuitable areas covering 3.90 km2, 8.57 km2, 16.94 km2, and 216.63 km2, respectively. These areas represent 1.58%, 3.48%, 6.88%, and 88.05% of the total habitat area, respectively. The potential distribution area of B. racemosa demonstrated significant variations under three climate scenarios (SSP126, SSP245, and SSP585), particularly in Asia, Africa, and Oceania. Both low and high suitable areas experienced a slight increase in distribution. In summary, the research suggests that B. racemosa primarily flourishes in coastal regions of tropical and subtropical areas near the equator, with temperature and precipitation playing a significant role in determining its natural range. This study offers important implications for the preservation and control of B. racemosa amidst habitat degradation and climate change threats. Through a comprehensive understanding of the specific habitat needs of B. racemosa and the implementation of focused conservation measures, efforts can be made to stabilize and rejuvenate its populations in their natural environment.

Benthic habitat mapping for estimating seagrass carbon stock across Takabonerate Islands, Indonesia

Data on benthic habitat cover are essential for monitoring and managing coastal areas, providing valuable ecosystem services for local communities. Moreover, seagrass extent is crucial for estimating carbon stock using Tier-1 calculations. On the other side, remote sensing technology has proven effective in mapping benthic habitat cover, including seagrass, over large local areas. Therefore, this research aims to map specific benthic habitats in a local area to obtain high-accuracy estimates of seagrass extent for carbon stock estimation. The study was conducted in the Takabonerate Islands, Indonesia, using Sentinel-2A imagery. The study involved field data processing, which enabled the mapping of eight benthic habitat classes using Sentinel-2A images, along with the steps for Sentinel-2A image processing for benthic habitat mapping. The benthic habitat map was produced following image correction steps, including atmospheric, sunglint, and water column corrections, followed by image classification using a Neural Net Classifier (NNC). Seagrass carbon stock estimation was performed using the Tier-1 equation from IPCC 2013. The study revealed a total benthic habitat area of 57,538.04 ha, with a seagrass area of 3127.42 ha for carbon stock estimation. The potential seagrass carbon stock in the study area was estimated to range from 337.76 GgC/ha to 31.27 GgC/ha using the Tier-1 equation. The overall accuracy of the benthic habitat map was 80.5 %, calculated using a confusion matrix table. The spatial information from this study can be used by local coastal managers and governments for baseline and monitoring purposes. The key interpretations from this study provide valuable findings that can be adapted and improved for future local mapping purposes.

Ten lessons for rare wildlife species conservation when coming from a common species background

AbstractEfforts to slow biodiversity loss have ushered in an era of proactive conservation for rare species, or species that have any combination of low relative abundance, high habitat specificity, and limited geographic range. Approaches to wildlife management and conservation were often developed for more abundant, generalist species, and frequently do not translate well to rare species. Conservation for rare species therefore requires adapting knowledge, action and inquiry tools for common species to rare species. We therefore present 10 lessons for adapting conservation tools to rare species, each with advice to implement the lessons. Several themes emerge from these lessons. Information scarcity necessitates high standards of information for rare species. Missing rare species information can be complemented with multiple forms of knowledge, particularly when the need for conservation action precludes additional data collection. Investment in depth (over breadth) of information for individuals of rare species can provide alternatives to population trend, which has lower reliability for rare species. Natural history documentation can improve rare species conservation strategies. Finally, curiosity‐driven inquiry can inspire rare species conservation innovation. We hope providing guidance that addresses challenges for rare species will help others bridge the gap between common wildlife approaches and proactive rare species conservation.

Climate warming impacts on ringed seal breeding habitat in Svalbard

Global warming is occurring at an accelerated rate in the Arctic compared to other parts of the planet with sea-ice declines being among the most striking manifestations of Arctic climate-related changes. Impacts of ongoing Arctic environmental change have been documented for biota throughout marine ecosystems from protists to top predators. Ice-dependent species with specific habitat needs are particularly vulnerable to the ongoing changes. The ringed seal (Pusa hispida) is an ice-associated Arctic endemic species that gives birth and rests in snow caves built in drifts of snow over holes in the sea ice created and maintained by these seals. In this study we create a snow-on-sea-ice reproductive lair habitat model for ringed seals in the Svalbard Archipelago (Norway), a hot-spot of Arctic warming. We use SnowModel, a physics-based snow distribution and evolution simulation system, as the core for a lair habitat model. The model quantifies snow depth and blowing snow fluxes and also relates these variables to snow availability for seal lair habitat. This was accomplished by developing an ecologically informed snow variable that quantifies potential seal lair habitat availability as a function of blowing snow fluxes. Model simulations were performed for the period September 1987 – August 2021 (34 years) on a 500 m × 500 m grid using a daily time-step. Field observations of snow depth and gridded analyses of sea-ice concentration and near-surface (+10 m) atmospheric forcing (air temperature, relative humidity, precipitation, and wind speed and direction) were incorporated within the model simulations. The results show that both snow depth and potential seal lair habitat have been decreasing in Svalbard for the last two decades. If current trends continue, as expected, ringed seal lair habitat will cease to exist across much of the Svalbard Archipelago in the next decade, putting this important Arctic species at risk of regional extirpation.

Biogeographical distribution and community assembly of Myxococcota in mangrove sediments

BackgroundMyxococcota, characterized by their distinct social lifestyles, are widely distributed micro-predators in global sediments. They can feed on a wide range of bacterial, archaeal, and fungal prey. Myxococcota are capable of producing diverse secondary metabolites, playing key roles in microbial food webs, and regulating the microbial community structures in different ecosystems. However, Myxococcota are rarely pure cultured due to the challenging and stringent culturing conditions. Their natural distribution, niche differentiation, and predator–prey relationships in a specific habitat are poorly understood.ResultsIn this study, we conducted a comprehensive analysis of the 16S rRNA gene sequence data from public databases and our collection. We compared the abundance, diversity, and distribution patterns of Myxococcota in various habitats, with a specific focus on mangroves. We found that Myxococcota accounted for 1.45% of the total prokaryotes in global sediments based on the abundance of 16S rRNA genes. Myxococcota are abundant and diverse in mangrove sediments. They tend to be more generalistic in mangroves than in other habitats due to their wide niche breadth. Besides, the deterministic processes (variable selection) influenced the assembly of mangrove Myxococcota communities significantly more than stochastic processes. Further, we determined that environmental factors explained a greater amount of total community variation in mangrove Myxococcota than geographical variables (latitude and sediment depth). In the end, through the analysis of microbial co-occurrence networks, Myxococcota emerges as a key component and functions as a connector in the mangrove microbial community.ConclusionsOur study enhances comprehension of mangrove Myxococcota's biogeography, assembly patterns, driving factors, and co-occurrence relationships, as well as highlights their unique niche and ecological importance in mangrove sediments.

Contrasting patterns of spatial genetic structure in endangered southern damselfly (Coenagrion mercuriale) populations facing habitat fragmentation and urbanisation

AbstractAimHuman‐induced environmental changes result in habitat loss and fragmentation, impacting wildlife population genetic structure and evolution. Urbanised and geographically peripheral areas often represent unfavourable environments, reducing connectivity among populations and causing higher population genetic differentiation and lower intra‐population genetic diversity. We examined how geographic peripherality and anthropogenic pressures affect genetic diversity and genetic differentiation in the protected southern damselfly (Coenagrion mercuriale, Odonata), which has low dispersal capabilities and specific habitat requirements and whose populations are declining.LocationWe studied two areas: one in semi‐natural habitats at the periphery of the species geographic range (northern France) and the other more central to the species' range, in an urbanised area surrounding the city of Strasbourg (Alsace, eastern France).MethodsWe genotyped 2743 individuals from 128 populations using 11 microsatellite loci. We analysed the spatial distribution of neutral genetic diversity (allelic richness, heterozygosity, levels of inbreeding and genetic relatedness), the extent of genetic differentiation and population affiliations (sPCAs) within the two areas. We also examined fine‐scale patterns of gene flow in the urbanised area of Alsace by investigating patterns of isolation by distance and estimating effective migration surfaces (EEMS) method.ResultsNorthern peripheral populations showed lower levels of genetic diversity and higher levels of genetic differentiation than central Alsacian populations. Although located in anthropised habitats, geographically central Alsacian populations showed high levels of gene flow, with dispersal events mainly occurring overland and not restricted to watercourses. However, the highly urbanised city of Strasbourg negatively impacted nearby populations by reducing levels of genetic diversity and increasing population genetic differentiation.Main ConclusionsThese results showed the need for management action by restoring breeding sites and creating migratory corridors for peripheral southern damselfly populations. However, our results also highlighted the resilience of southern damselfly in central range populations facing strong urbanisation pressures.

An ecological-evolutionary perspective on the genomic diversity and habitat preferences of the Acidobacteriota.

Members of the phylum Acidobacteriota inhabit a wide range of ecosystems including soils. We analyzed the global patterns of distribution and habitat preferences of various Acidobacteriota lineages across major ecosystems (soil, engineered, host-associated, marine, non-marine saline and alkaline, and terrestrial non-soil ecosystem) in 248,559 publicly available metagenomic datasets. Classes Terriglobia, Vicinamibacteria, Blastocatellia, and Thermoanaerobaculia were highly ubiquitous and showed clear preference to soil over non-soil habitats, class Polarisedimenticolia showed comparable ubiquity and preference between soil and non-soil habitats, while classes Aminicenantia and Holophagae showed preferences to non-soil habitats. However, while specific preferences were observed, most Acidobacteriota lineages were habitat generalists rather than specialists, with genomic and/or metagenomic fragments recovered from soil and non-soil habitats at various levels of taxonomic resolution. Comparative analysis of 1930 genomes strongly indicates that phylogenetic affiliation plays a more important role than the habitat from which the genome was recovered in shaping the genomic characteristics and metabolic capacities of the Acidobacteriota. The observed lack of strong habitat specialization and habitat transition driven lineage evolution in the Acidobacteriota suggest ready cross colonization between soil and non-soil habitats. We posit that such capacity is key to the successful establishment of Acidobacteriota as a major component in soil microbiomes post ecosystem disturbance events or during pedogenesis.

The influence of humidity gradient in a forest on ground spider assemblages: a preliminary study

A forest is a dynamic formation developed through evolutionary transformations that have progressed over a long time. Bioindication can help us understand changes occurring in a forest. Spiders play a significant role in biomonitoring. The presence of stenotopic spiders is affected by several factors, of which water availability is vital. According to the assumptions underlying water retention programs, water accumulated in retention reservoirs is expected to stimulate higher biodiversity of habitats. An analysis of the effect of a moisture gradient on the appearance of epigeic spiders in the Dąbrówka Forest Subdistrict has demonstrated the highest species diversity in the transect located closest to retention reservoirs (93 species). The species diversity of epigeic spiders decreased with the growing distance from these water reservoirs (transect B: 84 species; transect C: 70). Inverse relationships were determined with regard to the numbers of captured spiders (transect A: 927 specimens; B: 1134; C:1288). The spider species that dominated quantitatively was the forest species Pardosa lugubris, caught most abundantly in the area assigned to transect C (76.28%). A higher humidity gradient of a habitat (transects A and B) favors the occurrence of characteristic species with specific habitat and moisture requirements, which are ecologically valuable.

Spatial Pathology of Earthquake Management in Salas Babajani County, Kermanshah, Iran

Background and objective Human settlements are formed and developed in a specific natural environment. Social, political, cultural, and economic systems that govern the societies can affect residential spaces. Therefore, the special natural and human habitats cause the formation of special spaces, which require their own management system. After the earthquake on November 12, 2017, in Salas Babajani County, Kermanshah, Iran, whose epicenter was Ezgeleh district, the presence of natural areas in the county caused the crisis management in this region to face special problems. In addition, the sectoral and centralized management structure governing the country and thus the Salas Babajani County added to the complexity of these problems and caused the residents of this region to suffer a deep crisis. The aim of the current study is a spatial pathology of earthquake management in urban and rural settlements of Salas Babajani County. Method This is a descriptive-analytical study. Data were collected using the documentary method and a researcher-made questionnaire. Participants were the residents of Salas Babajani County. Results The findings showed that the earthquake management in the County has a high compliance with the centralized and sectoral management model. In addition, it was found that the crisis management in the four stages (prevention, preparedness, response, and recovery) was in an unfavorable situation. the highest weakness was in the prevention stage and the lowest weakness was related to the preparedness stage. Conclusion Overall, the results showed that crisis management has worsened by moving away from the center towards the outskirts, especially towards the southwestern borders. In other words, by moving away from the political center of the County (Tazeh Abad district), the crisis management became very unfavorable. Also, it was found that the crisis management was greatly influenced by the spatial factors of elevation, land slope, transportation network, distribution of human settlements, and population density.

Response of the subalpine bunchgrasses to wildfires and its effects in the relative abundance of the volcano rabbit in the Ajusco-Chichinautzin Mountain Range.

The volcano rabbit (Romerolagus diazi) is a lagomorph endemic to the central mountains of the Trans-Mexican Volcanic Belt and is classified as threatened at extinction risk. It is a habitat specialist in bunchgrass communities. The annual wildfires that occur throughout its distribution range are a vulnerability factor for the species. However, the effects of wildfires on volcano rabbit populations are not fully understood. We evaluated the occupancy and change in the volcano rabbit relative abundance index in the burned bunchgrass communities of the Ajusco-Chichinautzin Mountain Range during an annual cycle of wildfire events. Additionally, we assessed the factors that favor and limit occupation and reoccupation by the volcano rabbit using the relative abundance index in burned plots as an indicator of these processes. The explanatory factors for the response of the volcano rabbit were its presence in the nearby unburned bunchgrasses, the height of three species of bunchgrass communities, the proportion of different types of vegetation cover within a 500 m radius around the burned plots, heterogeneity of the vegetation cover, and the extent of the wildfire. Statistical analyses indicated possible reoccupation in less than a year in burned bunchgrass communities adjacent to unburned bunchgrass communities with volcano rabbits. The relative abundance index of volcano rabbits was not favored when the maximum height of the Muhlenbergia macroura bunchgrass community was less than 0.77 m. When the vegetation around the burned plots was dominated by forest (cover >30% of the buffer) and the fire was extensive, the number of latrines decreased per month but increased when the bunchgrass and shrub cover was greater around the burned plots. While the statistical results are not conclusive, our findings indicate a direction for future projects, considering extensive monitoring to obtain a greater number of samples that contribute to consolidating the models presented.

Flowering Plant Diversity of Differentially Disturbed Region of Terai Sal (Shorea robusta) Forest in Eastern Nepal

Terai Sal (Shorea robusta C.F.Gaertn.) forest, characteristic forest of lowland of Nepal, faces direct and indirect impacts from various anthropogenic activities. The present work aimed to study and document the flowering plant diversity within differentially disturbed sites of Charali Sal forest. Additionally, we accessed the habitat condition, analyzed the invasion status and prioritize the threats faced by the plant communities and recommended ways to mitigate the prevalent threats. We employed purposive sampling technique to sample the forest areas and nested plot design for vegetation sampling. Thirty sample plots, each measuring 10 m × 10 m, were established on two differentially disturbed sites (disturbed and undisturbed) of Charali Sal forest. A total of 111 flowering plant species belonging to 39 families were documented in the sampling sites, with 90 total species (89 identified) in disturbed sites and 86 species (80 identified) in undisturbed sites. Although the disturbed sites contained higher number of flowering plants, the diversity indices (Simpson and Shannon-wiener’s) indicated higher diversity on undisturbed site. Disturbed site exhibited higher human encroachment and higher invasion of alien species compared to undisturbed site. Specific habitat management plans should be devised for the control and eradication of invasive species from the Charali Sal forest. We highly recommend to delimit a buffer zone all around the forest perimeter to regulate local access inside the forest. Collecting and harvesting various forest products should be restricted to the buffer zone, while the inner forest areas should be under careful and strict management. Implementing these strict managemental strategies would be challenging, but it is crucial for preserving the natural integrity of the forest.

Combining biotelemetry and genetics provides complementary insights relevant to the management and conservation of a freshwater predator (Esox lucius) living in brackish lagoons

To inform the management of wild fish populations, it is equally important to understand both the ecological connectivity of habitat patches, apparent at annual and seasonal scales, and the genetic connectivity, emerging at evolutionary scales across generations. Ecological connectivity indicates the potential for rapid recolonization upon local depletion, while genetic connectivity informs about the conservation needs related to the evolution of subpopulations and ecotypes in metapopulations. We combined acoustic biotelemetry and pooled-genome sequencing to study a northern pike (Esox lucius) population as a model of a freshwater piscivore that inhabits a network of shallow brackish lagoons in the southern Baltic Sea. We found limited ecological connectivity among genetically similar subpopulations of pike, suggesting a metapopulation structure characterized by discrete local subpopulations with infrequent migrations between them. Connectivity of different lagoons increased during spawning, suggesting directed spawning migrations to either freshwater rivers or low salinity patches in connected lake-like bays. Spawning site fidelity to either brackish or freshwater spawning sites was observed, further contributing to the reproductive isolation of certain subpopulations. The genetic population structure aligned with salinity gradients and geographical distance and was significant between pairs of rivers draining into the lagoon network, but it was unrelated to ecological connectivity. The results collectively suggest that local subpopulations may not rapidly replenish upon local depletion and that even weak connectivity among subpopulations was sufficient to maintain genetic homogeneity across lagoons with similar salinity levels. Effective management and conservation of species forming metapopulations, such as the coastal northern pike studied here, necessitate localized approaches that adapt fishing mortality to local abundance and promote access to specific habitats, especiallyrivers, during spawning to conserve the entire genetic biodiversity and foster resilience of the metapopulation.

Species-specific erosion of genetic diversity in grassland butterflies depends on landscape land cover

Changes in land cover, particularly agricultural intensification, are a primary cause of pollinator decline. Decline and isolation can reduce genetic diversity, reducing adaptive potential and unmasking genetic load. Maintenance of functional connectivity in changing landscapes is necessary to ensure persistence, but how land cover impacts genetic diversity and functional connectivity in butterflies remains poorly understood. We assess to which extent land cover functionally isolates grassland butterfly populations and what consequences isolation has for genetic diversity using whole genome and land cover data. We assess species-specific patterns across three butterfly species that vary in habitat specialization and mobility - Polyommatus icarus, Plebejus argus and Cyaniris semiargus - using samples from 6 to 11 populations across a ~25,000 km2 area in southern Sweden. We find that while generalist Po. icarus is nearly panmictic and heathland specialist Pl. argus maintains modest functional connectivity, grassland specialist C. semiargus exists in largely isolated populations. Genetic diversity in all species is positively related to grassland extent in the surrounding landscape. Arable and forest extent are positively and negatively related to genetic diversity in Po. icarus, while the inverse is true in C. semiargus. Lower functional connectivity in C. semiargus is coupled with higher rates of inbreeding, suggesting more urgent need of conservation action aimed at restoring functional connectivity in this species, illustrating how genetic data can reveal threats that may go unnoticed with abundance data alone. We conclude that specialist butterfly genetic diversity relies upon preservation of well-connected semi-natural grasslands to maintain functional connectivity at longer distances.

Estimating Biogeochemical Rates Using a Computationally Efficient Lagrangian Approach

Nutrient concentrations in many estuaries have increased over the past century due to increases in wastewater discharge and increased agricultural intensity, contributing to multiple environmental problems. Numerous biogeochemical and physical processes in estuaries influence nutrient concentrations during transport, resulting in complex spatial and temporal variability and challenges identifying predominant processes and their rates. Mechanistic models which require these rates to quantify biogeochemical processes become complex and difficult to calibrate as the number of processes and parameters grows, owing to the high dimensionality of the parameter space and the computational cost of simultaneously modeling the transport and transformations of constituents. We developed a modeling approach that decouples transport from transformations, enabling fast, data-driven exploration of the parameter space. The approach extracted information including water age, cumulative exposure to specific habitats, and mean water depth exposure from a hydrodynamic model. Using this information, a biogeochemical model was implemented to predict ammonium and nitrate concentrations in a Lagrangian frame. The model performed each simulation in milliseconds on a laptop computer, allowing the fitting of rate parameters for key transformations by optimization. The optimization used fixed station nitrate observations and the model was then validated against high-resolution mapping observations of ammonium and nitrate. The results suggest that the observed spatial and temporal variation can be largely represented with five transformation processes and their associated rates. Dissolved inorganic nitrogen (DIN) losses occurred only in shallow vegetated areas in the model, highlighting that biogeochemical processes in these areas should be included in DIN models.

Pleistocene and modern distribution of the subterranean rodent Myospalax myospalax (Rodentia, Myospalacidae) in response to environmental factors

The question of the modern and past distribution of Siberian zokor Myospalax myospalax (Laxmann, 1773) continues to be an unresolved puzzle. This Western Siberian endemic species belongs to the family Myospalacidae, a group of subterranean rodents. The distribution of M. myospalax went through dramatic changes due to mass hunting in the first half of the 20th century and later development of agriculture. Because of this, data from various studies executed in different years do not always match, making it difficult to determine the natural limiting factors in the distribution of Siberian zokors. In turn, paleontological data from different regions are fragmentary and have not been summarized in a single study. We aimed to review the past and modern distribution of M. myospalax and examine its relationship with environmental factors such as climate and soils distribution. We hypothesized that this species may be a good indicator of past environmental conditions because of its special habitat characteristics. We gathered and revised published data to reconstruct the distribution before the anthropogenic influence of the 20th century and during the Pleistocene and Holocene epochs. The modern preanthropogenic range was compared with the distribution of soil complexes and provinces. We also examined M. myospalax molars from Late Pleistocene – Holocene localities and compared them with the modern population. The Siberian zokor distribution data provided herein will be useful for researchers from other regions who use fragmentary or doubtful data on the topic. We also identified climatic and soil parameters of M. myospalax habitat. These parameters can be used to reconstruct past environmental conditions from paleontological findings of the Siberian zokor.

Contrasting diversity patterns and drivers of aquatic macroinvertebrates in floodplain and non-floodplain wetlands

Understanding diversity patterns and underlying drivers is one of the central topics in the fields of biogeography and community ecology. Aquatic macroinvertebrates are widely distributed in various wetlands and play vital ecological roles. Previous studies mainly have focused on macroinvertebrate diversity in a single type of wetland. Our understanding of the differences in diversity patterns and underlying drivers between different wetland types remains limited. Here, we compared diversity patterns and community assembly of floodplain wetlands (FWs) and non-floodplain wetlands (NWs) in the Sanjiang Plain, Northeast China. We found that the taxonomic richness and abundance were higher in NWs than those in FWs. Nineteen taxa were identified as habitat specialists in the NWs, whereas only four taxa were designated as habitat specialists in the FWs. In addition, the FW and NW assemblages exhibited contrasting compositions. Spatial and environmental variables explained the largest variations in the macroinvertebrate assemblages of NWs and FWs, respectively. Normalised stochasticity ratios and Sloan neutral models confirmed that the macroinvertebrate community assembly of both wetland types was driven largely by stochastic processes. Stochastic processes were more prominent in shaping macroinvertebrate communities of FWs, whereas a stronger dispersal limitation was detected in NWs. Our results revealed contrasting diversity patterns and assembly mechanisms of macroinvertebrate communities in FWs and NWs. We underscore the importance of flood disturbance in shaping wetland ecosystems in the Sanjiang Plain and highlight that conservation and restoration actions cover different types of wetland habitats.