Low Elevation Research Articles

Carbon dioxide fluxes and the dominant role of vegetation in recently created and reference Gulf Coast marshes

AbstractCoastal wetlands are one of the most productive ecosystems on Earth with the capacity to sequester large amounts of carbon dioxide (CO2). Wetland loss due to anthropogenic and natural causes reduces the carbon (C) storage capacity and potentially releases previously fixed C in biomass and soil to the water column and atmosphere through decomposition. Coastal wetland restoration has the potential to mitigate some of the C losses depending on the balance of C fluxes. However, the role of vegetation and environmental conditions in governing rates of C accumulation in restoration sites is not well resolved. The purpose of this study was to examine seasonal C fluxes, specifically, gross ecosystem productivity (GEP), ecosystem respiration (ER), and net ecosystem exchange (NEE) of CO2 in unvegetated and vegetated (Spartina alterniflora) areas of a 2‐year old created marsh, and S. alterniflora and Spartina patens communities in a “natural” reference brackish marsh. S. alterniflora‐dominated areas were sinks for CO2 in both the newly created and reference marsh with an average CO2 uptake rate of 7.0 ± 1.0 μmol m−2 s−1. The unvegetated areas in the newly created marsh and S. patens areas in the reference marsh had approximately net neutral CO2 fluxes. S. alterniflora areas of the created marsh had similar carbon fluxes to that in the reference marsh, despite a much lower soil organic matter content. Because vegetation develops much faster than soil properties, restored marshes can be a C sink equivalent to natural marshes as soon as the marsh is vegetated. Ecosystem productivity and C assimilation in S. alterniflora areas of the reference marsh were enhanced by lower elevations (up to 6 cm) and higher soil bulk density (up to 0.28 g cm−3). At similar elevations, S. alterniflora in both the created and reference marshes was a greater C sink than S. patens areas of the reference marsh. Our findings illustrate that establishment of vegetation is critical to promoting C sink functions in created marshes and, notably, species do matter.

Assessment of recent lake sediment conditions in the conterminous U.S.

This study provides the largest sediment quality assessment of lakes in the conterminous United States (U.S.). A variety of lakes (n = 1005) were selected based on the randomized, probabilistic sampling design of the broader 2017 National Lakes Assessment study. Surficial sediment samples (0–5 cm) were collected at one representative site (generally the deepest point) for each lake (n = 969). The samples were analyzed for 16 metal(loid)s, 25 polycyclic aromatic hydrocarbons (PAHs), 53 polychlorinated biphenyl (PCB) congeners, 27 legacy pesticides and metabolites, total organic carbon, and grain size. Metal(loid)s and PAHs were widely distributed due to natural and potential anthropogenic sources, with regional variations observed for lakes in the nine ecoregions encompassing the U.S. Most sites did not have detectable PCB congeners or legacy pesticides. An integrative chemical index of mean probable effect concentration quotients, composed of seven metal(loid)s and ƩPAH13, was used to assess sediment quality for the estimated population of 224,916 lakes in the conterminous U.S. Nationally, 26.5% (CI of 20–33%) of lakes were in good condition (corresponding to predicted low incidences of toxicity to benthic organisms), 69.3% (CI of 63–76%) of lakes were in fair condition, and 1.8% (CI of 0.6–3%) of lakes were in poor condition (corresponding to predicted high incidences of sediment toxicity). Unweighted metal(loid) and ƩPAH13 concentrations were compared to lake, watershed, and land use data. Deeper lakes were significantly more contaminated (or naturally enriched) with As, Cd, Cu, Pb, Hg, Zn, and ƩPAH13 than shallow lakes. Lakes at lower elevation were also associated with more contamination (or natural enrichment) of As, Cr, Pb, Hg, Ni, Zn, and ƩPAH13 than higher elevation lakes. Greater contamination was associated with watersheds containing larger percentages of developed land. This study demonstrates an approach which can be used by others to assess sediment quality in their jurisdictions.

Modeling the potential distribution and shift of an Algerian endangered endemic species (Cedrus atlantica) under climate change scenarios: Implications for conservation

Algeria is distinguished by its geographical and climatic diversity, which contains a varied flora and endemic species, being recognized as one of the biodiversity hot-spots of the Mediterranean region. Among its endemic species, the renowned Atlas cedar (Cedrus atlantica) is particularly notable as it exclusively grows in the Atlas Mountains. Classified as endangered species by the International Union for Conservation of Nature (IUCN) Red List, because of its endemism and also because dramatic declining populations over the past four decades. Forecasting the potential impact of climate change on the distribution of this species might help in devising effective conservation strategies. Under this backdrop, this study aimed to simulate the current distribution of suitable habitat for C. atlantica in Algeria and investigate the influence of climate change on its distribution range by the years 2050, 2070 and 2090. The distribution was modeled using Maximum Entropy (Maxent) based on locality information of 103 occurrence sites of the species and nine different environmental variables. The model showed that annual mean temperature and elevation were the most important environmental factors affecting the distribution of C. atlantica in Algeria. Currently, the total suitable habitats for this species, including both medium and high suitability habitats, cover a total area of 1,837 km2, yet its distribution is relatively narrow and fragmented. This area would obviously decrease under all future climate change scenarios, shifting northwestward and to higher elevations, where conditions conducive to the species’ expansion will exist. Our results showed that at lower elevations and latitudes the species is highly prone to the effects of climate change, and they are confronted with an augmented risk of extinction across diverse climatic scenarios. This research provides valuable information for the more effective conservation and sustainable management of C. atlantica in the face of climate change challenges.

Drivers of Anuran Assemblage Structure in a Subtropical Montane Region.

Elevation gradients provide excellent semi-experimental conditions to investigate how the spatial distribution of biodiversity is shaped by the environment. Here, we investigate how temperature, productivity, and elevation are related to the diversity of anuran assemblages in a montane region of the southern Brazilian Atlantic Forest. We sampled 20 half-hectare plots between 2020 and 2021, distributed along a sharp elevation gradient. Anuran species richness and abundance decreased with increasing elevation. We show a positive relationship between ambient temperature and frog species richness and abundance, highlighting the importance of temperature in shaping assemblages along the elevation gradient. In contrast, productivity did not affect species richness and abundance, suggesting that available energy via resources does not limit local frog diversity. We further observed marked differences in the composition of anuran assemblages between low and high elevation areas, which were related to temperature. Beta diversity is mainly driven by species replacements among assemblages, which were likely related to environmental conditions. These findings highlight the importance of incorporating protected areas that encompass the entire range of elevations to capture the full complement of landscape-scale diversity. This is crucial as species showed limited distributions, and the marked effects of temperature should be explicitly considered under future scenarios of elevated upslope warming.

Forecasting the Effects of Global Change on a Bee Biodiversity Hotspot.

The Mojave and Sonoran Deserts, recognized as a global hotspot for bee biodiversity, are experiencing habitat degradation from urbanization, utility-scale solar energy (USSE) development, and climate change. In this study, we evaluated the current and future distribution of bee diversity, assessed how protected areas safeguard bee species richness, and predicted how global change may affect bees across the region. Using Joint Species Distribution Models (JSDMs) of 148 bee species, we project changes in species distributions, occurrence area, and richness under four global change scenarios between 1971 and 2050. We evaluated the threat posed by USSE development and predicted how climate change will affect the suitability of protected areas for conservation. Our findings indicate that changes in temperature and precipitation do not uniformly affect bee richness. Lower elevation protected areas are projected to experience mean losses of up to 5.8 species, whereas protected areas at higher elevations and transition zones may gain up to 7.8 species. Areas prioritized for future USSE development have an average species richness of 4.2 species higher than the study area average, and lower priority "variance" areas have 8.2 more species. USSE zones are expected to experience declines of up to 8.0 species by 2050 due to climate change alone. Despite the importance of solitary bees for pollination, their diversity is often overlooked in land management decisions. Our results show the utility of JSDMs for leveraging existing collection records to ease the inclusion of data-limited insect species in land management decision-making.

Importance of the interplay between land cover and topography in modeling habitat selection

Anthropogenic land cover change is one of the greatest threats to the persistence of organisms. Therefore, identifying and safeguarding optimal land covers for declining organisms is a major challenge of the Anthropocene. Priority land covers are typically identified through habitat selection studies. These traditionally use land cover and/or topographic features as separate, additive predictors of organismal occurrence, despite the fact that each land cover is superimposed on specific topographic features, such as elevation or slope, which may affect its attractiveness. Here, we tested the importance of considering the largely overlooked interplay between land cover and topography, using as a model a golden eagle Aquila chrysaetos population which is sharply declining due to human-induced land cover alteration. We found that the overlay of a key land cover type (old-growth forest) on underlying terrain known to be favorable for the population (steep slopes at higher elevations than the nest) dramatically increased its attractiveness. Conversely, the matching of the same land cover with unfavorable topography (gentle slopes at lower elevations) deteriorated its attractiveness for the population. Thus, underlying topography acted as the major determinant of land cover suitability for the eagle population. The conservation implications could be profound, because modeling land cover per se could waste conservation resources on low quality sites (old-growth forest on gentle terrain at low elevations) with unlikely benefits for the threatened eagle population. We expect topographic modulators of land cover quality to be more common than previously appreciated in many or most study systems, as numerous organisms inhabiting terrestrial and aquatic environments, regardless of taxonomic group, exhibit selectivity for specific topographic features and specific land cover types. In conclusion, we encourage modelers to take more into account underlying modulators that may drive differences in quality within the same land cover. This would make wildlife-habitat models more realistic, improve their applicability, and enhance the cost-effectiveness of conservation efforts.

High Inter-Specific Diversity and Seasonality of Trunk Radial Growth in Trees Along an Afrotropical Elevational Gradient.

Understanding mechanisms driving tropical tree growth is essential for comprehending carbon sequestration and predicting the future of tropical forests amid rapid deforestation. We conducted a natural experiment in Mount Cameroon to identify climatic factors limiting diurnal and seasonal growth in dominant tree species across a 2200-m elevation gradient, from lowland rainforests to montane mist forests with distinct wet and dry seasons. Using high-precision automatic dendrometers, we recorded radial growth rates of 28 tropical tree species from 2015 to 2018, correlating them with rainfall (11 100-2500 mm) and temperatures (23-14°C) across elevations. Significant growth limitations were suggested at both extremes of water availability. Tree growth peaked during the dry and prewet seasons at humid lower elevations and during wet seasons at drier higher elevations. Growth rates increased with soil moisture at higher elevations and peaked at medium soil moisture at lower elevations. Trees grew fastest at lower temperatures relative to their elevation-specific means, with growth limited by high daytime temperatures and promoted by nighttime temperatures. Our results revealed significant interspecific diurnal and seasonal growth variations hindered by both water scarcity and excess in West African rainforests, essential for forecasting and modelling carbon sinks.

Colonization and extinction lags drive non‐linear responses to warming in mountain plant communities across the Northern Hemisphere

Global warming is changing plant communities due to the arrival of new species from warmer regions and declining abundance of cold‐adapted species. However, experimentally testing predictions about trajectories and rates of community change is challenging because we normally lack an expectation for future community composition, and most warming experiments fail to incorporate colonization by novel species. To address these issues, we analyzed data from 44 whole‐community transplant experiments along 22 elevational gradients across the Northern Hemisphere. In these experiments, high‐elevation communities were transplanted to lower elevations to simulate warming, while also removing dispersal barriers for lower‐elevation species to establish. We quantified the extent and pace at which warmed high‐elevation communities shifted towards the taxonomic composition of lower elevation communities. High‐elevation plant communities converged towards the composition of low‐elevation communities, with higher rates under stronger experimental warming. Strong community shifts occurred in the first year after transplantation then slowed over time, such that communities remained distinct from both origin and destination control by the end of the experimental periods (3‐9 years). Changes were driven to a similar extent by both new species colonization and abundance shifts of high‐elevation species, but with substantial variation across experiments that could be partly explained by the magnitude and duration of experimental warming, plot size and functional traits. Our macroecological approach reveals that while warmed high‐elevation communities increasingly resemble communities at lower elevations today, the slow pace of taxonomic shifts implies considerable colonization and extinction lags, where a novel taxonomic composition of both low‐ and high‐elevation species could coexist for long periods of time. The important contribution of the colonizing species to community change also indicates that once dispersal barriers are overcome, warmed high‐elevation communities are vulnerable to encroachment from lower elevation species.

Impacts of habitat loss by reservoir inundation on occurrence, abundance, and genetic diversity of an imperiled, river-adapted, benthic-specialist fish, Etheostoma lemniscatum (Tuxedo Darter)

AbstractDams homogenize habitat and alter natural depth and flow regimes of lotic habitats, leading to extirpation of many stream-adapted fishes such as darters (Percidae). The Tuxedo Darter, Etheostoma lemniscatum, is a habitat-specialist of shallow, flowing pools with cobble substrate in the Big South Fork Cumberland River. One threat to this species is Wolf Creek Dam on the Cumberland River that creates Lake Cumberland, which during summer pool, inundates the lower 72 river kilometers (rkms) of the Big South Fork. A six-year period of lower reservoir elevations for dam repairs allowed a 9 rkm reach to return to riverine habitat and E. lemniscatum to colonize this reach. Once dam repairs were complete, the lower 72 rkms were again regularly inundated by Lake Cumberland. To determine the impact of post-dam repair inundation on E. lemniscatum, we compared occurrence, abundance, and genetic diversity metrics estimated from samples from 2015 and from several years post-inundation in 2019 and 2020 from 11 sites spanning the species’ range. Declines in occurrence and abundance were detected within the re-inundated reach. We observed low genetic diversity for the species for both sample periods, but no significant changes in genetic diversity between years. A trend towards lower allelic richness and an increase in the proportion of private alleles was observed in the 2019/2020 samples. Coupled with local extirpation and declines in abundance, these trends may be early warning signs of future declines in genetic diversity. We suggest future genetic monitoring to identify any time delayed responses to inundation not detected herein.

Influence of Soil Extractable Plant Nutrients on the Walnut Kernel Ionome in Southern Kyrgyzstan at Different Elevations

Abstract Background and Aims Climate change causes altered precipitation patterns and temperature increases, which may affect food quantity and quality. In Kyrgyzstan anticipated temperature changes are expected to influence the physiology of walnuts (Juglans regia L.) and soil properties relevant to plant nutrition, thereby impacting walnut fruit quality. This study explores the relationship between plant available nutrients in soil and walnut fruit nutrient content as affected by future temperature changes. Methods The soil samples were collected in the walnut forests of Southern Kyrgyzstan from top- and subsoils at three elevation levels (1000, 1300, and 1600 m above sea level). The walnut samples were collected from the same sampling sites and both soil Mehlich-3 extracts and acid digests of walnut fruits analyzed by ICP-OES. Results The results revealed no consistent relationship between Mehlich-3 extractable elements and walnut extractable elements, except for a weak negative correlation with zinc (Zn). Stronger relationships were observed among soil elements, but no clear associations with elevation levels were found. The walnut kernel ionome exhibited differences, particularly in calcium (Ca) and potassium (K) concentrations, with the low elevation site showing higher Ca and lower K concentrations compared to the high elevation site. Conclusions Differences in average temperature as caused by elevation did not affect available plant nutrients in the soil but altered the walnut kernel ionome and thus affected the walnut quality in the investigated forest systems. Future investigations should focus on climate change effects, such as altered precipitation patterns and drought, which may impact walnut fruit development and kernel properties.

Patterns and Mechanisms of Legume Responses to Nitrogen Enrichment: A Global Meta-Analysis.

Nitrogen (N), while the most abundant element in the atmosphere, is an essential soil nutrient that limits plant growth. Leguminous plants naturally possess the ability to fix atmospheric nitrogen through symbiotic relationships with rhizobia in their root nodules. However, the widespread use of synthetic N fertilizers in modern agriculture has led to N enrichment in soils, causing complex and profound effects on legumes. Amid ongoing debates about how leguminous plants respond to N enrichment, the present study compiles 2174 data points from 162 peer-reviewed articles to analyze the impacts and underlying mechanisms of N enrichment on legumes. The findings reveal that N enrichment significantly increases total legume biomass by 30.9% and N content in plant tissues by 13.2% globally. However, N enrichment also leads to notable reductions, including a 5.8% decrease in root-to-shoot ratio, a 21.2% decline in nodule number, a 29.3% reduction in nodule weight, and a 27.1% decrease in the percentage of plant N derived from N2 fixation (%Ndfa). Legume growth traits and N2-fixing capability in response to N enrichment are primarily regulated by climatic factors, such as mean annual temperature (MAT) and mean annual precipitation (MAP), as well as the aridity index (AI) and N fertilizer application rates. Correlation analyses show that plant biomass is positively correlated with MAT, and tissue N content also exhibits a positive correlation with MAT. In contrast, nodule numbers and tissue N content are negatively correlated with N fertilizer application rates, whereas %Ndfa shows a positive correlation with AI and MAP. Under low N addition, the increase in total biomass in response to N enrichment is twice as large as that observed under high N addition. Furthermore, regions at lower elevations with abundant hydrothermal resources are especially favorable for total biomass accumulation, indicating that the responses of legumes to N enrichment are habitat-specific. These results provide scientific evidence for the mechanisms underlying legume responses to N enrichment and offer valuable insights and theoretical references for the conservation and management of legumes in the context of global climate change.

Anatomy of a deep Piedmont critical zone: Evaluating hypotheses on regolith depth controls through comparison of ridge and valley boreholes

AbstractControls on the physical and chemical architecture of the subsurface critical zone are somewhat controversial, with multiple hypotheses proposed to account for variations in the depth of weathering between sites, and with landscape position at a site. In the Piedmont region of the Mid‐Atlantic US weathering of crystalline bedrock has been observed to extend tens of meters below the surface and groundwater in a'bow‐tie’ shape – i.e. weathering extends to lower elevations below ridges than below channels. The chemical and physical structure of a hillslope transect in the Maryland Piedmont was explored with a 45 m borehole in the ridge, as well as shallow bedrock boreholes at the toe of the slope and valley. Chemical weathering fronts were characterized using elemental abundances and mineralogical analysis. The ridge borehole did not extend deeper than the chemically and physically weathered rock. Surface and borehole geophysics and density measurements were used to characterize the weathered rock and saprolite. Na and Ca results suggest that plagioclase feldspar weathering is similar between samples collected from 45 m under the ridge and 2.2 m under the valley bottom. A narrow Fe oxidation garnet weathering front co‐insides with the transition from weathered bedrock to saprolite, suggesting that this reaction may generate initial saprolite porosity. Muscovite weathering co‐occurs with complete depletion of plagioclase a few meters above the Fe oxidation front. These nested weathering fronts in the saprolite appear to follow a subdued version of the surface topography. The location and shape of the nested saprolite weathering fronts may be controlled by the feedback between the transport of reactants and solutes and reaction‐generated porosity, consistent with the conceptual “valve” hypothesis. Differing dominant control mechanisms on deep bedrock weathering and saprolite initiating reactions may explain the thickness and structure of the critical zone at our site.

India's flood risk assessment and mapping with multi-criteria decision analysis and GIS integration

ABSTRACT India's diverse geography poses significant flood risks, addressed in this study through the geographic information system and multi-criteria decision analysis. This comprehensive flood risk assessment considers seven parameters: mean annual precipitation, elevation, slope, drainage density (DD), land use and land cover, proximity to roads, and distance to rivers. The findings indicate that flood vulnerability is primarily influenced by rainfall, elevation, and slope, with DD, land use, and proximity to roads and rivers also playing crucial roles. Experts weighed these factors to create a thorough flood risk map using the normalized rank index and normalized weight index, categorizing areas into five risk levels: very high, high, moderate, low, and very low. The study reveals that 3.40% of the area is at very high risk, 32.65% at high risk, 39.72% at moderate risk, 20.97% at low risk, and 3.25% at very low risk. These results highlight how human and natural factors interact to influence flood risk, with vulnerable areas characterized by low elevations, steep slopes, high drainage densities, and proximity to rivers or roads. The findings provide valuable insights for policymakers, scientists, and local authorities to develop strategies to mitigate flood losses across India's varied landscapes.

Deuterium in drinking water and its effects on cancer and longevity

ABSTRACT This study investigates the spatial distribution of longevity levels, deuterium in drinking water, and cancer incidence rates, and further examines the impact of deuterium in drinking water on longevity and cancer incidence. Methods such as correlation coefficients and Kriging spatial interpolation were employed to uncover the characteristics of spatial distribution and identify correlations. Findings reveal that regions with higher longevity levels are mostly located on the eastern side of the Hu Huanyong Line (Heihe-Tengchong Line). Deuterium in drinking water decreases from low latitude, low elevation, and coastal areas to high latitude, high elevation, and inland regions. Notably, there is a positive correlation between deuterium content in drinking water and longevity levels, indicating that higher deuterium content is associated with increased longevity. Additionally, counties with lower deuterium content in drinking water show a reduced incidence of cancer cases.

Bat Species Diversity in the Merapoh Rich Limestone-rich Area within Lipis National Geopark, Malaysia.

Merapoh, Pahang, is an area rich with limestone karst located within the Lipis National Geopark and home to the Sungai Relau gate of Taman Negara Pahang, a totally protected rainforest in Malaysia. Much of the research conducted here is mainly inside the National Park, with few published faunal records for the Merapoh caves. This study compiled the data on the bat species diversity of eight Merapoh caves (March 2020 to March 2022) using mist nets and harp traps. Our results indicate that Chiroptera diversity at Merapoh caves is rich, with a total of 32 species recorded from 865 individuals and four new locality records for the State of Pahang, namely Rousettusleschenaultii, Lyrodermalyra, Rhinolophuscoelophyllus and Hipposiderospomona. Gua Gunting has the highest diversity of bats recorded in this study (19 species). Significant Merapoh caves with bat colony roosts in Merapoh include Gua Jinjang Pelamin (Eonycterisspelaea & Rousettusleschenaultii), Gua Tahi Bintang (Hipposideroslarvatus) and Gua Pasir Besar (Miniopterusmedius). Rhinolophusconvexus, previously recorded only in upper montane rainforests, was also recorded in Merapoh caves indicating that this species can also be found in lower elevations than previously thought. Based on the findings of the current study and additional records from two previous studies, the Merapoh bat species diversity checklist totalled up to 38 species. On the whole, the rich bat diversity in Merapoh is reflective of its immense limestone karst landscape, which highlights the reason Lipis National Geopark has been recently gazetted. Future bat research should continue here and in other karsts within Lipis Geopark to sustainably conserve biological diversity, manage geological structures and raise awareness amongst the locals to appreciate their national heritage.

Will climate change constrain the altitudinal range of threatened species? Experimental evidence from a biodiversity hotspot.

A fundamental goal in ecology and evolution is to explain the factors that shape species' abundance and range limits. Evaluating the performance of early life-stages across an altitudinal gradient can be valuable for understanding what factors shape range limits and for predicting how plant species may respond to climate change. To experimentally evaluate the presence of local adaptation in a threatened palm (Euterpe edulis) at early life-stages, we reciprocally sowed seeds at two contrasting elevations. In addition, to evaluate the effect of seed predation on E. edulis seed germination and seedling establishment, seed addition experiments were conducted at three different elevations. Our results showed no evidence of local adaptation in the early life-stages for the two E. edulis populations. We observed lower germination and seedling performance of both E. edulis populations at the low-elevation site. The exclusion of seed predation increased seedling establishment across all elevations. Seed predation and dry soil conditions were the main factors that constrained seedling establishment at the upper altitudinal limit and at the lower elevation, respectively. Climate change in the study area will result in warmer and drier environmental conditions. The lack of local adaptation and the lower performance of both E. edulis populations in warm and dry conditions, combined with a higher seed predation at the upper altitudinal limit, might cause an altitudinal range contraction, increasing the vulnerability of this threatened species to climate change.

Abstract 4117646: The Ultimate Test in Hemocompatibility: HeartMate3 Restart After Prolonged Pump Shut Down

Introduction: The HeartMate 3 (HM3) LVAD, was shown to have a higher survival free of hemocompatibility related adverse events (HRAE) compared to its predecessors (HM2, HVAD). Superior HM3 outcomes are attributed to wide blood flow pathways coupled with frictionless movement and intrinsic pulsatility, reducing shear stress and blood stasis. It is unknown if improved hemocompatibility can withstand pump restart after prolonged shutdown. We herein report a case of HM3 pump stoppage without subsequent HRAE. Case Presentation: A 41-year-old male underwent HVAD implant in 2019 for advanced non-ischemic cardiomyopathy. This was exchanged to HM3 for recurrent neurological events despite therapeutic anticoagulation. Ten months after exchange, he awakened one morning to find his LVAD had been off for an unknown period but had not heard any device alarms (85dB if on battery power, 165dB if on wall power). Since he felt well he changed to battery power resulting in immediate pump restart. Log file analysis showed pump stoppage 2 am – 10 am, without preceding low flow alarms or power elevations. Management and Outcomes: In the ER INR was 1.5 (2.8 one week prior) and systemic heparin was started. Evaluation included: 1) CT brain without acute infarcts 2) echocardiogram without intracardiac thrombus 3) CT Angiography with patency of the inflow cannula and outflow graft 4) stable serial LDH measurements. The controller was exchanged, and analysis noted normal function. 1-year later the patient is maintained on warfarin and aspirin 325mg without further HRAE. Given the patient’s neurologic history and pump stoppage event, we did not invoke ARIES trial guidance and thus continued aspirin. Conclusion: Pump stoppage occurs when there is complete battery depletion, disconnection of both power leads, or the percutaneous lead from system controller. Our case is unique in that the duration of pump shutdown was 8 hours and INR subtherapeutic, without HRAE in the background of neurologic events on HVAD support. It has been previously reported that complete outflow graft thrombosis can occur shortly after LVAD decommissioning. The HM3 User Manual recommends restarting the pump immediately if off for a few minutes and using clinical judgment for longer durations due to increased risk for thromboembolic events. Our case adds to the paucity of existing data on improved hemocompatibility of the HM3 during rare circumstances of the ultimate test in hemocompatibility: complete pump shut down.

Status of Redband Trout and Nonnative Trout in the Wood River Basin, Idaho

Abstract The Wood River Basin in central Idaho has been isolated from the surrounding Snake River Basin by Malad Gorge Falls for at least 50,000 years, and recent genetic analyses suggest that Redband Trout Oncorhynchus mykiss gairdneri in the basin represent a previously undescribed lineage. To assess their contemporary status, we electrofished 22 study reaches in 2021-2022 previously occupied by Redband Trout when originally surveyed in 2003. Our objective was to assess changes in the occurrence and density of Redband Trout, Brook Trout Salvelinus fontinalis, and Brown Trout Salmo trutta. In 2021-2022, Redband Trout were absent in 5 of the 22 originally occupied reaches with Brook Trout as the only salmonid species present at all extirpated reaches. Brook Trout have now been extirpated from two reaches previously occupied with Redband Trout as the only salmonid species present at both reaches. Brown Trout colonized one new reach since 2003 and are now present at all study reaches (n = 3) which exceed 10 m average stream wetted width. Average fish density increased from 2003 to 2021-2022 across all study reaches for total trout (all species combined) and at nearly all study reaches for each individual trout species. Changes in Redband Trout density were unrelated to changes in nonnative trout density. On average Redband Trout composition (of all trout at each reach) across all study reaches decreased by 13% while Brook Trout and Brown Trout increased by 8% and 4%, respectively from 2003 to 2021-2022. Nevertheless, Brook Trout are increasingly present in headwater streams while Brown Trout occupy larger, lower elevation rivers, potentially threatening the long-term conservation of Redband Trout in the Wood River Basin. Although additional data is warranted to more completely understand the distribution of trout, these preliminary results suggest that management activities may be necessary to control the further spread of nonnative salmonids in the basin.

Unraveling demographic patterns in tropical birds across an elevational gradient

Abstract An increasing body of evidence has displayed upslope shifts in the high-diversity avian communities of tropical mountains. Such shifts have largely been attributed to warming climates, although their actual mechanisms remain poorly understood. One likely possibility is that changes in species-specific demographic rates underlie elevational range shifts. Fine-scale population monitoring and capture–mark–recapture (CMR) analysis could shed light on these mechanisms but, until recently, analytical constraints have limited our ability to model multiple demographic rates across bird communities while accounting for transient individuals. Here, we used Bayesian hierarchical multi-species CMR models to estimate the apparent survival, recruitment, and realized population growth rates of 17 bird species along an elevational gradient in the cloud forests of Honduras. For 6 species, we also modeled demographic rates across elevation and time. Although demographic rates varied among species, population growth rates tended to be higher in lower elevation species. Moreover, some species showed higher population growth rates at higher elevations, and elevational differences in growth rates were positively associated with previous estimates of upslope shifts at the study site. We also found that demographic rates showed contrasting trends across the duration of the study, with recruitment decreasing and apparent survival increasing, and stronger effects at lower elevations. Collectively, we provide the methodological tools to encourage more multi-species demographic analyses in other systems, while highlighting the potential for the demographic impacts of global change. We provide a Spanish translation in the Supplementary Materials.

Vegetation changes of Lushan, China between 1959 and 2020 based on pollen data

Both climatic change and human activity are currently driving the dynamic of vegetation, which may vary from region to region. On Lushan, located in the eastern China, the subtropical secondary forests during the natural succession endure the pressure from ongoing climate warming on the one hand. They are influenced by anthropogenic disturbance on the other hand for recent decades. Previously, palynological research has discovered that the pollen assemblages from surface soil sample on Lushan can basically reflect the characteristics of local vegetation. Here, we did a comparative study by using the pollen analysis to investigate the vegetation changes of Lushan from 1959 to 2020. We compared the composition of pollen assemblages obtained in 1959 with that in 2020 along different altitudes. Further, the biomisation method was employed to discover the changes of different vegetation types, which were reflected by the pollen-based reconstructed biomes. Meanwhile, the temporal beta diversity analysis was used to extract the sites experienced the significant vegetation shift and the most important taxa change. Results showed that the pollen composition over the past 60 years on Lushan had altered remarkably. The vegetation shifted at all altitudes. The current vegetation pattern of Lushan: evergreen broadleaved forest in low elevation, temperate deciduous broadleaved forest in middle elevation and cool mixed forest in high elevation, is the successional consequence of the past 60 years. The forces driving the vegetation dynamics might be from multiple sources. However, the human disturbance seems to play quite an important role during forest succession. Our study is potentially useful both for paleoecological reconstructions and wider understanding of current climate change that are relevant to subtropical forests of Asia.