Changes In Distribution Of Species Research Articles

Effects of human and nonhuman predation risk on antipredator movement behaviors of an upland game bird

AbstractPredators elicit antipredator behaviors such as proactive and reactive movements in prey, but both are rarely investigated simultaneously. Impacts of human predation risk on antipredator behaviors can be greater than those of nonhuman predators, resulting in increased effects on populations and community structure. We compared the influence of human and nonhuman predation risk on proactive and reactive antipredator movement behaviors of male Eastern wild turkeys (Meleagris gallopavo, hereafter turkey). We used simultaneously collected GPS locations from 31 turkeys and 36 coyotes (Canis latrans) to investigate the antipredator behavior of turkeys to coyotes. To assess antipredator behaviors of turkeys to hunters, we used 1661 hunting tracks collected while monitoring 109 turkeys. For proactive movements, we quantified how predation risk influenced resource selection. To investigate reactive movements, we quantified changes in movement behavior of turkeys after encountering hunters and coyotes. Coyote and turkey home range overlap was high, but lack of core area overlap, encounters, and similar resource selection suggested the use of different areas on the landscape. Turkeys selected areas associated with decreased coyote risk and closer to hardwoods. Coyotes preferred shrubs and open areas, suggesting turkeys avoided coyote risk and the habitats coyotes preferred. We detected 17 coyote and turkey contacts, and the probability of contact decreased by 16.6% for every 100 m farther from a forest edge. Turkeys did not display reactive movement behaviors after a direct encounter with coyotes, as step lengths were similar prior to and after encounters, which did not differ from random step lengths. After hunting, turkeys selected areas farther from public access points and closer to private property, suggesting proactive avoidance of hunter risk. We detected 31 hunter and turkey contacts; increased step lengths after hunter contacts suggested fleeing behavior. The probability of a hunter–turkey contact decreased by 5.5% for every 100 m farther from a secondary road. Antipredator movement behaviors by turkeys suggest coyote risk to be low over a broad temporal window, while hunter risk is high for a narrow temporal window. We provide insight into how human‐induced fear can cause antipredator behavioral responses greater than nonhuman fear, potentially causing changes in species distribution and community structure.

Changes in parasite species distributions could be driven by host range expansions: the case of hybridisation between two Australian reptile ticks

Anthropogenic stressors such as climate change and diminishing habitats cause widespread disturbances in species distributions for a variety of taxa. Range shifts and hybridisation following secondary contact become of particular importance when it comes to parasites such as ticks, as they are dependent on their host distributions and can carry numerous harmful pathogens. We aimed to determine if two parapatric reptile tick species, Amblyomma albolimbatum and A. limbatum, hybridise at their parapatric boundary by comparing morphological and genomic variation using single nucleotide polymorphisms. Our results show that both tick species were genomically distinct, but hybridisation has occurred. We found a hybrid and an A. limbatum outside of their previously known range, suggesting there could have been a shift in tick distribution. What were thought to be hybrids due to intermediate morphological traits were not hybrids but morphological variants of the parental species. This information suggests more distinctive morphological features are needed for identifying these tick species and that novel environmental conditions and a broadening of tick niche due to hybridisation could increase host exposure to different pathogens.

Long term changes in aquaculture influence migration, regional abundance, and distribution of an avian species.

Agricultural development has been causing changes to the environment and the abundance and distribution of avian species. Agriculture is dynamic with changes in products occurring at large scales over relatively short time periods. The catfish aquaculture industry is one such agriculture industry that has undergone dramatic changes over the last 25 years. The double-crested cormorant (Nannopterum auritum) is a piscivorous bird that has an extensive history with the aquaculture industry of Mississippi due to its depredation of cultured catfish. A large-scale monitoring program began in 1989 to estimate the abundance and location of cormorants at every known roost in the primary catfish producing region of the state, regionally known as the Delta. We used this data set to address hypotheses pertaining to cormorant ecology within the Delta over time, particularly in relation to aquaculture. We found that, although the Midwest breeding population of cormorants has been increasing, the abundance of cormorants wintering in the Delta has been decreasing, closely following the decline of aquaculture, suggesting aquaculture area is the primary reason for cormorant inhabitation of the region. We also modeled cormorant presence and abundance at all roost sites to determine what factors most influenced cormorant distribution. Aquaculture area around roosts was a significant predictor of both cormorant presence and abundance. However, the influence of aquaculture area was seasonally dependent, with greater positive influences occurring prior to migration. Lastly, we found peak cormorant abundance in the Delta is occurring 2.14 days earlier each year, which may be indicative of changes to migration phenology. Information gained using this large dataset aids in cormorant damage mitigation and to further our understanding of cormorant ecology. Data indicate changes in agriculture, and potentially climate change, can influence phenology, distribution, and abundance of avian species at large geographic scales.

RANGE EXPANSION AND POPULATION PATTERNS ON THE WAVE OF COLONIZATION: THE MIDDAY GERBIL (<i>MERIONES MERIDIANUS</i> PALLAS 1773, MURIDAE, RODENTIA) IN KALMYKIA TAKEN AS A MODEL

The mechanisms of species dispersal and colonization that drive the process of range expansion have always been in the focus of fundamental ecology. Normally, species ranges change slowly, but human activities through global processes (landscape transformations, climate warming, and biological invasions) have speeded up changes in species distributions, thus providing opportunities to observe and study range shifts in real time. In Kalmykia, southern European Russia, human-induced landscape transformations from desert to steppe and vice versa, allowed us to study the colonization process as a result of range expansion in the desert-dwelling rodent, Midday gerbil (Meriones meridianus). We studied the population dynamics, demographic characteristics of gerbils, their physical conditions, and infestation with fleas on the wave of colonization compared to the source population. We found that, during recent years, the species range has been rapidly expanding to the west, where gerbils have formed new colonies. The colonists differed significantly from the residents of the source population in a lower average body weight, this being associated not with the poorer physical condition, but with age structure: the fertility rate of female colonists was much higher, and the population of colonists was much younger, compared to the source population. In addition, colonists were much less infested with fleas. Our findings indicate that the population of colonists on the wave of colonization does not experience the negative effects of low numbers, whereas the age structure and high reproductive rate of the younger population accounts for its rapid growth and expansion.This research was supported by the Russian Science Foundation (project number 22-14-00223, https://rscf.ru/project/22-14-00223/).

Climate change-related growth improvements in a wide niche-breadth tree species across contrasting environments.

The vulnerability and responsiveness of forests to drought are immensely variable across biomes. Intraspecific tree responses to drought in species with wide niche breadths that grow across contrasting climatically environments might provide key information regarding forest resistance and changes in species distribution under climate change. Using a species with an exceptionally wide niche breath, we tested the hypothesis that tree populations thriving in dry environments are more resistant to drought than those growing in moist locations. We determined temporal trends in tree radial growth of 12 tree populations of Nothofagus antarctica (Nothofagaceae) located across a sharp precipitation gradient (annual precipitation of 500-2000 mm) in Chile and Argentina. Using dendrochronological methods, we fitted generalized additive mixed-effect models to predict the annual basal area increment as a function of year and dryness (De Martonne aridity index). We also measured carbon and oxygen isotope signals (and estimated intrinsic water-use efficiency) to provide potential physiological causes for tree growth responses to drought. We found unexpected improvements in growth during 1980-1998 in moist sites, while growth responses in dry sites were mixed. All populations, independent of site moisture, showed an increase in their intrinsic water-use efficiency in recent decades, a tendency that seemed to be explained by an increase in the photosynthetic rate instead of drought-induced stomatal closure, given that δ18O did not change with time. The absence of drought-induced negative effects on tree growth in a tree species with a wide niche breadth is promising because it might relate to the causal mechanisms tree species possess to face ongoing drought events. We suggest that the drought resistance of N. antarctica might be attributable to its low stature and relatively low growth rate.

Comparing Global Sentinel-2 Land Cover Maps for Regional Species Distribution Modeling

Mapping the spatial and temporal dynamics of species distributions is necessary for biodiversity conservation land-use planning decisions. Recent advances in remote sensing and machine learning have allowed for high-resolution species distribution modeling that can inform landscape-level decision-making. Here we compare the performance of three popular Sentinel-2 (10-m) land cover maps, including dynamic world (DW), European land cover (ELC10), and world cover (WC), in predicting wild bee species richness over southern Norway. The proportion of grassland habitat within 250 m (derived from the land cover maps), along with temperature and distance to sandy soils, were used as predictors in both Bayesian regularized neural network and random forest models. Models using grassland habitat from DW performed best (RMSE = 2.8 ± 0.03; average ± standard deviation across models), followed by ELC10 (RMSE = 2.85 ± 0.03) and WC (RMSE = 2.87 ± 0.02). All satellite-derived maps outperformed a manually mapped Norwegian land cover dataset called AR5 (RMSE = 3.02 ± 0.02). When validating the model predictions of bee species richness against citizen science data on solitary bee occurrences using generalized linear models, we found that ELC10 performed best (AIC = 2278 ± 4), followed by WC (AIC = 2367 ± 3), and DW (AIC = 2376 ± 3). While the differences in RMSE we observed between models were small, they may be significant when such models are used to prioritize grassland patches within a landscape for conservation subsidies or management policies. Partial dependencies in our models showed that increasing the proportion of grassland habitat is positively associated with wild bee species richness, thereby justifying bee conservation schemes that aim to enhance semi-natural grassland habitat. Our results confirm the utility of satellite-derived land cover maps in supporting high-resolution species distribution modeling and suggest there is scope to monitor changes in species distributions over time given the dense time series provided by products such as DW.

How future climate and tree distribution changes shape the biodiversity of macrofungi across Europe

AbstractAimClimate change is affecting biodiversity at an accelerating rate. Despite the importance of fungi in ecosystems in general, and in the global carbon and nitrogen cycle in particular, there is little research on the response of fungi to climate change compared with plants and animals. Earlier studies show that climatic factors and tree species are key determinants of macrofungal diversity and distribution at large spatial scales. However, our knowledge of how climate change will affect macrofungal diversity and distribution in the future remains poorly understood.LocationEurope.MethodsUsing openly available occurrence data of 1845 macrofungal species from eight European countries (i.e. Norway, Sweden, Finland, Denmark, Netherlands, Germany, France and Spain), we built ensemble species distribution models to predict macrofungal response to climate change alone and combined climate and tree distribution change under the IPCC special report on 2080 emissions scenarios (SRES A2 and B2).ResultsConsidering climate change alone, we predict that about 77% (74.1%–80.7%) of the modelled species will expand their distribution range, and around 57% (56.1%–58.4%) of the modelled area will have an increase in macrofungal species richness. However, when considering the combined climate and tree species distribution change, only 50% (50%–50.9%) of the species are predicted to expand their distribution range and 49% (47.4%–51.1%) of the modelled area will experience an increase in macrofungal species richness.Main ConclusionsOverall, our models projected that large areas would exhibit increased macrofungal species richness under future climate change. However, tree species distribution might play a restrictive role in the future distributional shifts of macrofungi. In addition, macrofungal responses appear heterogeneous, varying among species and regions. Our findings highlight the importance of including tree species in the projection of climate change impacts on the macrofungal diversity and distribution on a continental scale.

UAV-Hyperspectral Imaging to Estimate Species Distribution in Salt Marshes: A Case Study in the Cadiz Bay (SW Spain)

Salt marshes are one of the most productive ecosystems and provide numerous ecosystem services. However, they are seriously threatened by human activities and sea level rise. One of the main characteristics of this environment is the distribution of specialized plant species. The environmental conditions governing the distribution of this vegetation, as well as its variation over time and space, still need to be better understood. In this way, these ecosystems will be managed and protected more effectively. Low-altitude remote sensing techniques are excellent for rapidly assessing salt marsh vegetation coverage. By applying a high-resolution hyperspectral imaging system onboard a UAV (UAV-HS), this study aims to differentiate between plant species and determine their distribution in salt marshes, using the salt marshes of Cadiz Bay as a case study. Hyperspectral processing techniques were used to find the purest spectral signature of each species. Continuum removal and second derivative transformations of the original spectral signatures highlight species-specific spectral absorption features. Using these methods, it is possible to differentiate salt marsh plant species with adequate precision. The elevation range occupied by these species was also estimated. Two species of Sarcocornia spp. were identified on the Cadiz Bay salt marsh, along with a class for Sporobolus maritimus. An additional class represents the transition areas from low to medium marsh with different proportions of Sarcocornia spp. and S. maritimus. S. maritimus can be successfully distinguished from soil containing microphytobenthos. The final species distribution map has up to 96% accuracy, with 43.5% of the area occupied by medium marsh species (i.e., Sarcocornia spp.) in the 2.30–2.80 m elevation range, a 29% transitional zone covering in 1.91–2.78 m, and 25% covered by S. maritims (1.22–2.35 m). Basing a method to assess the vulnerability of the marsh to SLR scenarios on the relationship between elevation and species distribution would allow prioritizing areas for rehabilitation. UAV-HS techniques have the advantage of being easily customizable and easy to execute (e.g., following extreme events or taking regular measurements). The UAV-HS data is expected to improve our understanding of coastal ecosystem responses, as well as increase our capacity to detect small changes in plant species distribution through monitoring.

Climate‐influenced shifts in a highly migratory species recreational fishery

AbstractThe distribution of marine species is changing as a direct result of climate change. Large pelagic highly migratory species (HMS), like tunas, billfishes, and sharks, are particularly sensitive to environmental change due to their migratory nature and use of large‐scale ocean features. These temporal and spatial shifts are likely reflected in the Atlantic HMS recreational fishery and could have downstream effects on coastal communities. We utilized dockside intercept data from the Large Pelagics Survey (LPS) from 2002 to 2019, which conducts sampling from June to October and spans Maine to Virginia, USA. We assessed how species catch composition has changed and developed spatiotemporal models to understand latitudinal and temporal shifts in the recreational catch of 12 HMS groups. Latitudinal shifts were significantly affected by Northeast Shelf SST for 11 of the 12 HMS groups and ranged from 3 ± 1 km°C−1 for the large bluefin tuna to 40 ± 1 km°C−1 for the blue shark. In addition, the estimated day of the year when the first 25% of bigeye tuna intercepts occurred, happened over 50 days earlier in 2019 compared to 2002, suggesting the initial catch is happening earlier in recent years. These results suggest that changes in species distribution and phenology are affecting where and when HMS recreational catch occurs. Understanding these shifts would allow managers to be more responsive and flexible and also help communities prepare for changes, whether it would be a switch to a new species or shifts in the fishing season.

Status and Distribution of Freshwater Mussels in the Louisiana Section of Bayou Bartholomew

As a major tributary to the species-rich Ouachita River and one of the few remaining non-channelized rivers in the Alluvial Plains physiographic division, Bayou Bartholomew is a key ecosystem for the freshwater mussel diversity of southeast Arkansas and northeast Louisiana. Bayou Bartholomew is known to contain 16 mussel Species of Greatest Conservation Need (SGCN) but the mussel assemblage of the Louisiana section of Bayou Bartholomew has not been assessed since the early 2000s. In 2021, we sampled over 100 river km on the main channel of Bayou Bartholomew and four tributaries from just downstream of the Louisiana/Arkansas border to the confluence with the Ouachita River. We used a novel two-phase timed-search protocol to characterize the mussel assemblage and measured shell length (long axis) to determine the size distribution of each species encountered. A suite of relevant habitat variables and site attributes were also quantified or qualitatively noted. One site was selected for sampling using a grid survey to determine quantitative estimates of mussel density. Our survey confirmed the presence of 35 species including 12 SGCN in the Louisiana section of the Bayou Bartholomew drainage. In total, 3,292 live mussels representing 33 species were collected in the main channel, 234 live mussels representing 18 species were found in a quantitative grid, and four species were found in tributaries. Two additional species were only found in tributaries as dead shells. Length frequencies of all common and abundant species indicated ongoing annual recruitment. Patterns of ubiquity in the main channel of Bayou Bartholomew varied by species, and mussels were rare in the tributaries. Generalized linear modelling and non-metric multidimensional scaling analyses identified relationships between mussel assemblage composition and the distance from the confluence with the Ouachita River and habitat variables including substrates, depth, and mesohabitat types. A comparison with previous studies did not provide any evidence of major changes in overall mussel species distributions or occurrence in Bayou Bartholomew in Louisiana. We attribute the apparent stability in the mussel assemblage to the fact that major anthropogenic alterations such as channelization, impoundments, and watershed urbanization have been minimal since the earlier studies, and we conclude that Bayou Bartholomew will likely continue to be a hotspot of regional mussel diversity and a haven for several of Louisiana's SGCN if large-scale anthropogenic alterations to the system do not occur and management actions are taken to protect and allow for the persistence of heterogenous habitats.

Changes in Community Composition and Functional Traits of Bumblebees in an Alpine Ecosystem Relate to Climate Warming

Climate warming has been observed as the main cause of changes in diversity, community composition, and spatial distribution of different plant and invertebrate species. Due to even stronger warming compared to the global mean, bumblebees in alpine ecosystems are particularly exposed to these changes. To investigate the effects of climate warming, we sampled bumblebees along an elevational gradient, compared the records with data from 1935 and 1936, and related our results to climate models. We found that bumblebee community composition differed significantly between sampling periods and that increasing temperatures in spring were the most plausible factor explaining these range shifts. In addition, species diversity estimates were significantly lower compared to historical records. The number of socio-parasitic species was significantly higher in the historical communities, while recent communities showed increases in climate generalists and forest species at lower elevations. Nevertheless, no significant changes in community-weighted means of a species temperature index (STI) or the number of cold-adapted species were detected, likely due to the historical data resolution. We conclude that the composition and functionality of bumblebee communities in the study area have been significantly affected by climate warming, with changes in land use and vegetation cover likely playing an additional important role.

Whole genome demographic models indicate divergent effective population size histories shape contemporary genetic diversity gradients in a montane bumble bee.

Understanding historical range shifts and population size variation provides an important context for interpreting contemporary genetic diversity. Methods to predict changes in species distributions and model changes in effective population size (N e) using whole genomes make it feasible to examine how temporal dynamics influence diversity across populations. We investigate N e variation and climate-associated range shifts to examine the origins of a previously observed latitudinal heterozygosity gradient in the bumble bee Bombus vancouverensis Cresson (Hymenoptera: Apidae: Bombus Latreille) in western North America. We analyze whole genomes from a latitude-elevation cline using sequentially Markovian coalescent models of N e through time to test whether relatively low diversity in southern high-elevation populations is a result of long-term differences in N e. We use Maxent models of the species range over the last 130,000 years to evaluate range shifts and stability. N e fluctuates with climate across populations, but more genetically diverse northern populations have maintained greater N e over the late Pleistocene and experienced larger expansions with climatically favorable time periods. Northern populations also experienced larger bottlenecks during the last glacial period, which matched the loss of range area near these sites; however, bottlenecks were not sufficient to erode diversity maintained during periods of large N e. A genome sampled from an island population indicated a severe postglacial bottleneck, indicating that large recent postglacial declines are detectable if they have occurred. Genetic diversity was not related to niche stability or glacial-period bottleneck size. Instead, spatial expansions and increased connectivity during favorable climates likely maintain diversity in the north while restriction to high elevations maintains relatively low diversity despite greater stability in southern regions. Results suggest genetic diversity gradients reflect long-term differences in N e dynamics and also emphasize the unique effects of isolation on insular habitats for bumble bees. Patterns are discussed in the context of conservation under climate change.

Staying in situ or shifting range under ongoing climate change: A case of an endemic herb in theHimalaya‐HengduanMountains across elevational gradients

AbstractAimHow species respond to ongoing climate change has been a hot research topic, especially with the controversy in shifting range (movement) or persisting in local habitat (in situ) as the primary response. Assessing the relative roles of range shifts, phenotypic plasticity and genetic adaptation helps us predict the evolutionary fate of species. We aim to explore the evolutionary strategies of plants under climate change from a keystone herb in alpine ecosystems,Mirabilis himalaica, along its elevational gradient.LocationHimalaya‐Hengduan Mountains, China.MethodsWe combined evidence from population genomics and ecological data in both space and time to investigate the state of “staying” or “moving”. We identified migration events by assessing historical and contemporary gene flow and changes in species distribution. Morphological variation was compared by measuring five traits using specimen data. Moreover, we explored climate‐driven genetic variation and local selection regimes acting on populations in the alpine landscape along an elevational gradient.ResultsOur results argue that staying in situ by morphological variation and local genetic evolution rather than range shifting plays an important role inM. himalaicaresponse to climate change. We first found trace evidence of upward or climatic‐driven shifting along an elevational gradient, although asymmetric gene flow was restricted within microenvironments of mid‐elevational populations. Furthermore, morphological variation comparisons revealed clinal variation, as resource allocation showed a declining pattern in vegetative growth but increased reproductive growth with increasing elevation. Outlier tests and environment association analyses indicated adaptative loci primarily related to thermal‐driven selection and continuous adaptations to high elevation in the Himalaya‐Hengduan Mountains.Main ConclusionsOur findings showM. himalaicamay persist in local habitats rather than shifting range under climate change, exhibiting a low risk of genomic vulnerability in current habitats. This study has important implications in improving our understanding of the evolutionary response in alpine plants to climate change.

Optimism for the Future Use of Environmental DNA (eDNA) to Study Global Climate Change

Optimism for the Future Use of Environmental <scp>DNA</scp> (<scp>eDNA</scp>) to Study Global Climate Change

Ecological niches of epiphyllous bryophytes along Afrotropical elevation gradient

Understanding multiple environmental drivers governing tropical organisms' distribution and ecological niches is crucial for predicting their responses to ongoing rapid deforestation. While macroclimatic effects via energy and water availability are well predicted, less is known about locally modulating factors such as canopy structure, light and edaphic conditions. Here we show that minimum temperatures and ambient humidity drive the abundance and richness of leaf‐inhabiting epiphyllous bryophytes across 4‐km elevation gradient on Mount Cameroon, West Africa, separating epiphyll‐rich rainforests (0–2200 m a.s.l.) from epihyll‐poor fire‐driven afromontane savanna (2300–4000 m a.s.l.). However, local factors contribute more than half to the total abundance and richness variation, either directly (light) or indirectly (edaphic conditions) via their effects on host plant composition. The most abundant epiphyllous communities occur in vertically stratified upland rainforests between 600 and 1100 m elevation, where N‐fixing tree legumes dominate. Their canopy is relatively sparse, due to nutrient‐poor soils leached by high rainfall, leaving room for the development of diverse subcanopy tree and understory shrub and herb layers with epiphyll‐rich communities. Vertically homogenous lowland rainforests on fertile soils below 500 m, with dense overstory and shaded and species‐poor understory, have less developed epiphylls, as do seasonally dry montane forests between 2000 and 2300 m, or elephant fragmented forests between 1200 and 1600 m. We conclude that high temperature and humidity together with a vertically stratified canopy support epiphylls, whereas precipitation seasonality, disturbed vegetation with unstable microclimate, or dense, unstratified canopy discourage the development of epiphyllous communities. Our study illustrates that ecological niches of epiphyllous bryophytes are shaped by a complex interplay of multiple drivers, knowledge of which is essential for more realistic predictions of the impacts of current accelerated habitat loss on species distribution and diversity changes in the tropics.

Change in altitudinal distribution of Newfoundland Gray-cheeked Thrush ( Catharus minimus minimus ) revealed through historical stop-level breeding bird survey data

Breeding bird survey (BBS) data are typically analyzed at the route level in which the average or combined total number of individuals across the 50 stops is treated as a single observation. However, analysis at the stop level may provide information on finer-scale habitat affiliations of species within the broader landscape, as well as changes in species distribution over time. Though once abundant, the Newfoundland Gray-cheeked Thrush (<em>Catharus minimus minimus</em>) underwent a dramatic population collapse across most of the island during the 1980s and 1990s and today is most common in montane forests. The reason for this collapse is not well understood but introduced North American red squirrels (<em>Tamiasciurus hudsonicus</em>), which colonized most forested areas on the island below ~400 m from the late 1970s through the mid-1990s, have been identified as a possible cause. To improve our understanding of changes in the elevational distribution of Gray-cheeked Thrushes, we compared stop-level BBS data from two periods. Our historic period from 1974-1984 corresponds with the initial expansion phase of introduced red squirrels, whereas that from 2000-2015 reflects a period during which the colonization of suitable habitat by squirrels was complete. We used 17 routes (850 stops) where the thrushes had been observed and there were at least 3 surveys completed during each period. Surveys during the 1970s and 1980s indicated that Gray-cheeked Thrushes were abundant at all elevations sampled by the BBS (0-450 m), with higher incidence below 100 m and above 300 m; in contrast, recent surveys indicate that the species is now essentially absent below 350 m. This finding highlights the value of historical stop-level BBS data for reconstructing changes in species distributions and is consistent with the hypothesis that red squirrels have adversely affected Newfoundland Gray-cheeked Thrushes.

Changing Epidemiology of Pathogenic Bacteria Over the Past 20 Years in Korea.

The epidemiology of pathogenic bacteria varies according to the socioeconomic status and antimicrobial resistance status. However, longitudinal epidemiological studies to evaluate the changes in species distribution and antimicrobial susceptibility of pathogenic bacteria nationwide are lacking. We retrospectively investigated the nationwide trends in species distribution and antimicrobial susceptibility of pathogenic bacteria over the last 20 years in Korea. From 1997 to 2016, annual cumulative antimicrobial susceptibility and species distribution data were collected from 12 university hospitals in five provinces and four metropolitan cities in South Korea. The prevalence of Staphylococcus aureus was the highest (13.1%) until 2012 but decreased to 10.3% in 2016, consistent with the decrease in oxacillin resistance from 76.1% in 2008 to 62.5% in 2016. While the cefotaxime resistance of Escherichia coli increased from 9.0% in 1997 to 34.2% in 2016, E. coli became the most common species since 2013, accounting for 14.5% of all isolates in 2016. Pseudomonas aeruginosa and Acinetobacter baumannii rose to third and fifth places in 2008 and 2010, respectively, while imipenem resistance increased from 13.9% to 30.8% and 0.7% to 73.5% during the study period, respectively. Streptococcus agalactiae became the most common pathogenic streptococcal species in 2016, as the prevalence of Streptococcus pneumoniae decreased since 2010. During the same period, pneumococcal penicillin susceptibility decreased to 79.0%, and levofloxacin susceptibility of S. agalactiae decreased to 77.1% in 2016. The epidemiology of pathogenic bacteria has changed significantly over the past 20 years according to trends in antimicrobial resistance in Korea. Efforts to confine antimicrobial resistance would change the epidemiology of pathogenic bacteria and, consequently, the diagnosis and treatment of infectious diseases.

A perspective from the past in conservation of plant biodiversity in central China

Biodiversity has increasingly come under threat from human activity everywhere on Earth. China, with over 33,000 species of vascular plants, is a megadiverse region, in part because of its diversity in topography and climates. One of its most extensive biomes is broadleaved evergreen/warm mixed forest which dominates eastern Asia and Central China. There is some debate about how glacial/interglacial cycles across the Quaternary had an impact on this biome. There were certainly broad scale changes in distribution of many key species. Here, we examine the four palaeoecological records from Central China that contain both LGM and Mid-Holocene vegetation records and consider the degree of biodiversity in Central China with the aim of developing a broad overview of the history on plants in the region. It is clear that in the mountainous regions of Central China, many taxa survived the LGM in situ, showing that there was enough stable habitat to support key species. Some mountainous areas have high degrees of endemism which suggests that fragmentation of populations across glacial/interglacial cycles may have been an important component in favoring speciation. The consideration of past records and modern species distributions have significance in selecting conservation areas.

Ecological thresholds in Brazilian savanna: Environmental conditions modulating the composition of woody species in different substrates

Neotropical savannas are complex ecosystems whose species compositions are determined by different environmental factors, acting at regional (altitude, geomorphology, and climate) and local scales (substrate deep, soil properties, relief, and fire). We investigated the ecological thresholds, at the large (regional) and small scale (local), at the community levels of woody plants in two adjacent savanna environments. These savannas occur on distinct substrates with deep soils and flat relief (DS) and shallow soils with rocky outcrops and steep relief (RS). We compiled abundance data of the woody species and regional and local variables in 32 sites, with 1 ha each (16 DS and 16 RS). All sites are in protected areas with no recent sign of fire. We applied the Threshold Indicator Taxa Analysis (TITAN) to detect changes in species distribution in response to environmental predictors. The communities of the two environments differed in their responses to the local (soil properties) and regional (altitude), but climate had little influence on the vegetation of these environments. The woody communities of DS and RS present differences in response to predictors. We conclude that the distribution of species in both environments is determined by multiple and distinct factors, which depend on the scale analyzed.

Designing a large-scale track-based monitoring program to detect changes in species distributions in arid Australia.

Monitoring trends in animal populations in arid regions is challenging due to remoteness and low population densities. However, detecting species' tracks or signs is an effective survey technique for monitoring population trends across large spatial and temporal scales. In this study, we developed a simulation framework to evaluate the performance of alternative track-based monitoring designs at detecting change in species distributions in arid Australia. We collated presence-absence records from 550 2-ha track-based plots for 11 vertebrates over 13years and fitted ensemble species distribution models to predict occupancy in 2018. We simulated plausible changes in species' distributions over the next 15years and, with estimates of detectability, simulated monitoring to evaluate the statistical power of three alternative monitoring scenarios: (1) where surveys were restricted to existing 2-ha plots, (2) where surveys were optimized to target all species equally, and (3) where surveys were optimized to target two species of conservation concern. Across all monitoring designs and scenarios, we found that power was higher when detecting increasing occupancy trends compared to decreasing trends owing to the relatively low levels of initial occupancy. Our results suggest that surveying 200 of the existing plots annually (with a small subset resurveyed twice within a year) will have at least an 80% chance of detecting 30% declines in occupancy for four of the five invasive species modeled and one of the six native species. This increased to 10 of the 11 species assuming larger (50%) declines. When plots were positioned to target all species equally, power improved slightly for most compared to the existing survey network. When plots were positioned to target two species of conservation concern (crest-tailed mulgara and dusky hopping mouse), power to detect 30% declines increased by 29% and 31% for these species, respectively, at the cost of reduced power for the remaining species. The effect of varying survey frequency depended on its trade-off with the number of sites sampled and requires further consideration. Nonetheless, our research suggests that track-based surveying is an effective and logistically feasible approach to monitoring broad-scale occupancy trends in desert species with both widespread and restricted distributions.