Soil animal communities demonstrate simplification without homogenization along an urban gradient.

Urbanization profoundly impacts biodiversity and ecosystem function, exerting an immense ecological filter on the flora and fauna that inhabit it, oftentimes leading to simplistic and homogenous ecological communities. However, the response of soil animal communities to urbanization remains underexplored, and it is unknown whether their response to urbanization is like that of aboveground organisms. This study investigated the influence of urbanization on soil animal communities in 40 public parks along an urbanization gradient.

Unraveling spatial heterogeneity of soil legacy phosphorus in subtropical grasslands.

Humans have profoundly altered phosphorus (P) cycling across scales. Agriculturally driven changes (e.g.

Soil legacy phosphorus and loss risk in subtropical grasslands.

The accumulation of soil legacy phosphorus (P) due to past fertilization practices poses a persistent challenge for agroecosystem management and water quality conservation. This study investigates the spatial distribution and risk assessment of soil legacy P in subtropical grasslands managed for cow-calf operations in Florida, with two pasture types along the intensity gradient: improved vs semi-native pastures. Soil samples from 1438 locations revealed substantial spatial variation in soil legacy P, with total P concentrations ranging from 11.

Distribution, source apportionment, and ecological risk assessment of soil antibiotic resistance genes in urban green spaces.

Urban green spaces play a crucial role in cities by providing near-natural environments that greatly impacts the health of residents. However, these green spaces have recently been scrutinized as potential reservoirs of antibiotic resistance genes (ARGs), posing significant ecological risks. Despite this concern, our understanding of the distribution, sources, and ecological risks associated with ARGs remains limited.

Elevated atmospheric CO drives decreases in stable soil organic carbon in arid ecosystems: Evidence from a physical fractionation and organic compound analysis.

The increasing concentration of CO in the atmosphere is perturbing the global carbon (C) cycle, altering stocks of organic C, including soil organic matter (SOM). The effect of this disturbance on soils in arid ecosystems may differ from other ecosystems due to water limitation. In this study, we conducted a density fractionation on soils previously harvested from the Nevada Desert FACE Facility (NDFF) to understand how elevated atmospheric CO (eCO ) affects SOM stability.

Biochar may alter plant communities when remediating the cadmium-contaminated soil in the saline-alkaline wetland.

It is thought remediating cadmium pollution with biochar can affect plant traits. However, the potential impact of this practice on plant communities is poorly understood. Here, we established natural-germinated plant communities using soil seed bank from a saline-alkaline wetland and applied a biochar treatment in Cd-polluted wetland soil.

Severe multi-year drought coincident with Hittite collapse around 1198-1196 BC.

The potential of climate change to substantially alter human history is a pressing concern, but the specific effects of different types of climate change remain unknown. This question can be addressed using palaeoclimatic and archaeological data. For instance, a 300-year, low-frequency shift to drier, cooler climate conditions around 1200 BC is frequently associated with the collapse of several ancient civilizations in the Eastern Mediterranean and Near East.

A direct comparison of ecological theories for predicting the relationship between plant traits and growth.

Despite long-standing theory for classifying plant ecological strategies, limited data directly link organismal traits to whole-plant growth rates (GRs). We compared trait-growth relationships based on three prominent theories: growth analysis, Grime's competitive-stress tolerant-ruderal (CSR) triangle, and the leaf economics spectrum (LES). Under these schemes, growth is hypothesized to be predicted by traits related to relative biomass investment, leaf structure, or gas exchange, respectively.

Is variation in inter-annual precipitation a mechanism for maintaining plant metabolic diversity?

In order for diverse species to coexist in ecological communities, they must vary in ways that reduce competition. Often, this is done by some form of spatial niche separation where small differences in environment allow for coexistence among species. However, temporal separation of resources could also be a factor in driving community diversity.

Nitrogen pollution promotes changes in the niche space of fish communities.

Historically, anthropogenic fixed nitrogen has been purposely increased to benefit food production and global development. One consequence of this increase has been to raise concentrations of nitrogen in aquatic ecosystems. To evaluate whether nitrogen pollution promotes changes in the estimates of niche space of fish communities, we examined 16 sites along a Brazilian river basin highly impacted by anthropogenic activities, especially discharge of domestic and industrial sewage from a region with more than 5 million inhabitants.

Genome size influences adaptive plasticity of water loss, but not metabolic rates, in lungless salamanders.

Many expressions of phenotype, such as physiological performance, integrate multiple underlying traits to function. Linking component traits to adaptive physiology thus gives insight into mechanisms of selection acting on performance. Genome size (C-value) is a trait that influences physiology in multiple taxa by exerting a nucleotypic effect, constraining cell size and cellular physiology such that whole-organism mass-specific metabolism is reduced with increasing C-value.

Evidence That Microorganisms at the Animal-Water Interface Drive Sea Star Wasting Disease.

Sea star wasting (SSW) disease describes a condition affecting asteroids that resulted in significant Northeastern Pacific population decline following a mass mortality event in 2013. The etiology of SSW is unresolved. We hypothesized that SSW is a sequela of microbial organic matter remineralization near respiratory surfaces, one consequence of which may be limited O availability at the animal-water interface.

Mean annual temperature influences local fine root proliferation and arbuscular mycorrhizal colonization in a tropical wet forest.

Mean annual temperature (MAT) is an influential climate factor affecting the bioavailability of growth-limiting nutrients nitrogen (N) and phosphorus (P). In tropical montane wet forests, warmer MAT drives higher N bioavailability, while patterns of P availability are inconsistent across MAT. Two important nutrient acquisition strategies, fine root proliferation into bulk soil and root association with arbuscular mycorrhizal fungi, are dependent on C availability to the plant via primary production.

Impact of Mean Annual Temperature on Nutrient Availability in a Tropical Montane Wet Forest.

Despite growing understanding of how rising temperatures affect carbon cycling, the impact of long-term and whole forest warming on the suite of essential and potentially limiting nutrients remains understudied, particularly for elements other than N and P. Whole ecosystem warming experiments are limited, environmental gradients are often confounded by variation in factors other than temperature, and few studies have been conducted in the tropics. We examined litterfall, live foliar nutrient content, foliar nutrient resorption efficiency (NRE), nutrient return, and foliar nutrient use efficiency (NUE) of total litterfall and live foliage of two dominant trees to test hypotheses about how increasing mean annual temperature (MAT) impacts the availability and ecological stoichiometry of C, N, P, K, Ca, Mg, Mn, Fe, Zn, and Cu in tropical montane wet forests located along a 5.

Consequences of drought severity for tropical live oak (Quercus oleoides) in Mesoamerica.

In two Costa Rican and three Honduran sites that vary in rainfall and soil properties, we used natural isotopes, a soil water balance model, and broad-scale climate-based drought indices to study shifts in water use with ontogeny from seedlings to mature tropical live oak (Quercus oleoides) trees. Water use patterns help to explain persistence of this broadly distributed species in Mesoamerica and to evaluate likely threats of ongoing climate changes. At the end of the dry season, soil δ O profiles can be described by one-phase exponential decay curves.

Non-native mangroves support carbon storage, sediment carbon burial, and accretion of coastal ecosystems.

Mangrove forests play an important role in climate change adaptation and mitigation by maintaining coastline elevations relative to sea level rise, protecting coastal infrastructure from storm damage, and storing substantial quantities of carbon (C) in live and detrital pools. Determining the efficacy of mangroves in achieving climate goals can be complicated by difficulty in quantifying C inputs (i.e.

Isotope values of California vole (Microtus californicus) hair relate to historical drought and land use patterns in California, USA.

Increased drought frequency and intensity and agricultural intensification have been key stressors to ecological systems over the past century. Biological proxies (e.g.

Trophic responses to aquatic pollution of native and exotic livebearer fishes.

The objective of this study was to evaluate if aquatic pollution promote diet shifts in two livebearer fishes (Poeciliidae): an exotic species, the guppy (Poecilia reticulata), and a native livebearer (Phalloceros uai). The study was carried out in a Brazilian basin highly impacted by anthropogenic activities, especially discharge of domestic and industrial sewage from a region with more than five million human inhabitants. To evaluate the trophic ecology of both native and exotic species it was analysed carbon (δC) and nitrogen (δN) stable isotopes of fish tissue, food resources and, sewage.

Leaf stable isotopes suggest shared ancestry is an important driver of functional diversity.

Plant physiological strategies of carbon (C) and nitrogen (N) uptake and metabolism are often regarded as outcomes of environmental selection. This is likely true, but the role of evolutionary history may also be important in shaping patterns of functional diversity. Here, we used leaf C and N stable isotope ratios (δC, δN) as integrators of physiological processes to assess the relative roles of phylogenetic history and environment in a diverse group of Ericaceae species native to North America.

Natural selection and neutral evolutionary processes contribute to genetic divergence in leaf traits across a precipitation gradient in the tropical oak Quercus oleoides.

The impacts of drought are expanding worldwide as a consequence of climate change. However, there is still little knowledge of how species respond to long-term selection in seasonally dry ecosystems. In this study, we used Q -F comparisons to investigate (i) the role of natural selection on population genetic differentiation for a set of functional traits related to drought resistance in the seasonally dry tropical oak Quercus oleoides and (ii) the influence of water availability at the site of population origin and in experimental treatments on patterns of trait divergence.

Grazing alters net ecosystem C fluxes and the global warming potential of a subtropical pasture.

The impact of grazing on C fluxes from pastures in subtropical and tropical regions and on the environment is uncertain, although these systems account for a substantial portion of global C storage. We investigated how cattle grazing influences net ecosystem CO and CH exchange in subtropical pastures using the eddy covariance technique. Measurements were made over several wet-dry seasonal cycles in a grazed pasture, and in an adjacent pasture during the first three years of grazer exclusion.

Population-Level Differentiation in Growth Rates and Leaf Traits in Seedlings of the Neotropical Live Oak Grown under Natural and Manipulated Precipitation Regimes.

Widely distributed species are normally subjected to spatial heterogeneity in environmental conditions. In sessile organisms like plants, adaptive evolution and phenotypic plasticity of key functional traits are the main mechanisms through which species can respond to environmental heterogeneity and climate change. While extended research has been carried out in temperate species in this regard, there is still limited knowledge as to how species from seasonally-dry tropical climates respond to spatial and temporal variation in environmental conditions.

The impact of water management practices on subtropical pasture methane emissions and ecosystem service payments.

Pastures are an extensive land cover type; however, patterns in pasture greenhouse gas (GHG) exchange vary widely depending on climate and land management. Understanding this variation is important, as pastures may be a net GHG source or sink depending on these factors. We quantified carbon dioxide (CO ) and methane (CH ) fluxes from subtropical pastures in south Florida for three wet-dry seasonal cycles using eddy covariance, and estimated two annual budgets of CO , CH , and GHG equivalent emissions.

A novel allele for black coat colour reveals the Polynesian ancestry and hybridization patterns of Hawaiian feral pigs.

Pigs () have played an important cultural role in Hawaii since Polynesians first introduced them in approximately AD 1200. Additional varieties of pigs were introduced following Captain Cook's arrival in Hawaii in 1778 and it has been suggested that the current pig population may descend primarily, or even exclusively, from European pigs. Although populations of feral pigs today are an important source of recreational hunting on all of the major islands, they also negatively impact native plants and animals.