Menü
Deutsch | English

Neue wissenschaftliche Aufsätze


Ecosystems 

Latest Results for Ecosystems
The latest content available from Springer
Isotopic Evidence that Nitrogen Enrichment Intensifies Nitrogen Losses to the Atmosphere from Subtropical Mangroves
08. Januar 2019
Abstract Nitrogen (N) enrichment can have large effects on mangroves’ capacity to provide critical ecosystem services by affecting fundamental functions such as N cycling and primary productivity. However, our understanding of excess N input effects on N cycling in mangroves remains quite limited. To advance our understanding of how N enrichment via water or air pollution affects mangroves, we evaluated whether increasing N inputs would decrease biological N fixation (BNF), but intensify N dynamics and N losses to the atmosphere in these systems. We measured N...
Hydrologic Context Alters Greenhouse Gas Feedbacks of Coastal Wetland Salinization
02. Januar 2019
Abstract Changes in sea-level rise and precipitation are altering patterns of coastal wetland hydrology and salinization. We conducted paired laboratory (20 weeks) and field (15 weeks) marine salt addition experiments to disentangle the effects of hydrology (permanent versus intermittent flooding) and elevated marine salts (sulfate versus other salt ions) on greenhouse gas (GHG) emissions from freshwater forested wetland soils. Marine salt additions strongly affected GHG emissions in both experiments, but the magnitude, and even the direction, of GHG responses depended...
Retention of Nitrate-N in Mineral Soil Organic Matter in Different Forest Age Classes
02. Januar 2019
Abstract Conceptual models of nutrient retention in ecosystems suggest that mature forests receiving chronically elevated atmospheric nitrogen (N) deposition should experience increased nitrate (NO3−) losses to streams. However, at the Hubbard Brook Experimental Forest (New Hampshire, USA), recent stream NO3− concentrations have been unexpectedly low in mature watersheds. Poorly understood retention of NO3−-N in soil organic matter (SOM) may explain this discrepancy. The relative availability of C and N in SOM influences NO3−-N retention and may vary during...
Seagrass Sensitivity to Collapse Along a Hydrodynamic Gradient: Evidence from a Pristine Subtropical Intertidal Ecosystem
02. Januar 2019
Abstract Eutrophication causes tremendous losses to seagrass around the globe. The effects of nutrient loading vary along environmental gradients, and wave forces especially are expected to affect meadow stability, nutrient status, and responses to nutrient supply. Here, we surveyed the pristine subtropical intertidal seagrass system of Banc d’Arguin, Mauritania, to characterise Zostera noltii in terms of morphology (biomass allocation, leaf length and area, rhizome internode length), nutrient content (carbon: C, nitrogen: N, phosphorus: P, iron: Fe, aluminium: Al), and...
Landscape Evolution of a Fluvial Sediment-Rich Avicennia marina Mangrove Forest: Insights from Seasonal and Inter-annual Surface-Elevation Dynamics
02. Januar 2019
Abstract Mangrove forests are vulnerable to accelerated sea-level rise associated with climate warming because they occupy a relatively narrow zone on the mid-to-upper-intertidal flats. The fate of these ecosystems largely depends on their capacity to accrete sediment at a rate sufficient to maintain their elevation relative to sea level. We investigated the role of biophysical processes and feedbacks controlling surface-elevation dynamics in a fluvial sediment-rich Avicennia marina mangrove forest (New Zealand) at seasonal-to-inter-annual timescales (over 9 years) using...
Cross-Biome Drivers of Soil Bacterial Alpha Diversity on a Worldwide Scale
02. Januar 2019
Abstract We lack a defined suite of attributes that allow us to universally predict the distribution of bacterial diversity across and within globally distributed biomes. Using data from a global survey, including 237 locations and multiple environmental predictors, we found that only ultraviolet light, forest environments, soil carbon and pH can be considered as significant and globally consistent predictors of soil bacterial diversity, valid within and across biomes (arid, temperate and continental). Bacterial diversity always peaked in grasslands, with moderate-to-low...
Distinguishing Rapid and Slow C Cycling Feedbacks to Grazing in Sub-arctic Tundra
02. Januar 2019
Abstract Large grazers are known to affect ecosystem functioning even to the degree where ecosystems transition to another vegetation state. Alongside the vegetation change, several features of ecosystem functioning, such as ecosystem carbon sink capacity and soil carbon mineralisation rates, may be altered. It has remained largely uninvestigated how the grazing effects on carbon cycling processes depend on the duration of grazing. Here, we hypothesised that grazing affects ecosystem carbon sink through plant-driven processes (for example, photosynthesis) on shorter...
Suspended Dead Wood Decomposes Slowly in the Tropics, with Microbial Decay Greater than Termite Decay
02. Januar 2019
Abstract Coarse woody debris (CWD) is an important pool of carbon in forest ecosystems and is present in all strata as fallen, standing or suspended CWD. However, there are relatively few decomposition studies of CWD in tropical forests compared with temperate forests, and research on suspended CWD in particular has largely not been attempted. Termites are important decomposers in tropical ecosystems yet their role relative to microbial decomposers and the importance of the vertical location of CWD has rarely been considered. For the first time, we examined the relative...
Resurrecting the Lost Flames of American Chestnut
18. Dezember 2018
Abstract Loss of native foundation tree species to introduced pests profoundly alters the structure and function of many forest ecosystems. Recent advances to resurrect or prevent the loss of species by developing resistant hybrids hold promise, but uncertainty remains about the potential impacts of introducing a novel genotype on ecological processes, such as fire. A classic example of a non-native, pathogen-caused loss of a foundation species is American chestnut (Castanea dentata), a species now functionally extinct from the eastern US but undergoing experimental trials...
The Inhibitory Effects of Nitrogen Deposition on Asymbiotic Nitrogen Fixation are Divergent Between a Tropical and a Temperate Forest
18. Dezember 2018
Abstract Asymbiotic nitrogen (N) fixation (ANF) is an important source of N in pristine forests and is predicted to decrease with N deposition. Previous studies revealing N fixation in response to N deposition have mostly applied understory N addition approaches, neglecting the key processes (for example, N retention and uptake) occurring in forest canopy. This study evaluated the effects of N deposition on N fixation in the soil, forest floor, mosses, and canopy leaves in a temperate forest (in central China) and a tropical forest (in southern China) with different...
Foundations and Frontiers of Ecosystem Science: Legacy of a Classic Paper (Odum 1969)
18. Dezember 2018
Abstract Ecosystem ecology, like all scientific disciplines, is often propelled forward by “classic” papers that identify key concepts within the field and define the core questions for generations of scientists. Here, we examine the legacy and sustained impact of a paper long considered a classic in ecology, E.P. (Gene) Odum’s 1969 “The strategy of ecosystem development.” Odum’s paper presented testable predictions about species diversity, energy flow, and biogeochemical dynamics during ecosystem succession and provided guiding principles for environmental...
Microtopographic Drivers of Vegetation Patterning in Blanket Peatlands Recovering from Erosion
18. Dezember 2018
Abstract Blanket peatlands are globally rare, and many have been severely eroded. Natural recovery and revegetation (‘self-restoration’) of bare peat surfaces are often observed but are poorly understood, thus hampering the ability to reliably predict how these ecosystems may respond to climatic change. We hypothesised that morphometric/topographic-related microclimatic variables may be key controls on successional pathways and vegetation patterning in self-restoring blanket peatlands. We predicted the occurrence probability of four common peatland plant species...
Ant and Earthworm Bioturbation in Cold-Temperate Ecosystems
18. Dezember 2018
Abstract In temperate ecosystems, earthworms and ants are the most important organisms for bioturbation. Little is known about how these groups contribute to bioturbation in different environments and to what extent overall bioturbation depends on their diversity. We developed a formula that allows quantification of annual earthworm bioturbation, thereby taking differences between earthworm ecotypes into account. With this formula, we calculated earthworm bioturbation at three sites, each with vegetation types typically found in Northern Europe. Earthworm bioturbation was...
Does Grazing Matter for Soil Organic Carbon Sequestration in the Western North American Great Plains?
12. Dezember 2018
Abstract Considerable uncertainty remains regarding grazing-induced influences on soil organic carbon (SOC) sequestration in semiarid grassland ecosystems due to three important complications associated with studying such effects: (1) Ecologically meaningful shifts in SOC pools attributable to grazing are difficult to detect relative to inherently large grassland SOC pools, (2) a lack of baseline (pre-treatment) data, and (3) frequent lack of or limited replication of long-term grazing manipulations. SOC sequestration rates were determined in 74-year-old grazing...
Physical Transport Mechanisms Driving Sub-Antarctic Island Marine Ecosystems
10. Dezember 2018
Abstract The Southern Ocean is undergoing rapid environmental change, which has impacted its ecosystems and food webs. There is need for ecosystem models that incorporate all levels of the biotic system and consider physical context. Using an end-to-end ecosystem model of the Prince Edward Islands (PEIs), we investigated the importance of the input of oceanic nutrients, oceanic plankton, and run-off of terrestrial ammonium to nearshore production. We compared ecosystem state as group production rates and as the relative scale of pelagic versus demersal food web pathways...
Muskoxen Modify Plant Abundance, Phenology, and Nitrogen Dynamics in a High Arctic Fen
03. Dezember 2018
Abstract Herbivores are key drivers of vegetation dynamics in most ecosystems. However, the effect of high arctic herbivores on vegetation dynamics throughout a growing season is not well understood. In this study, we examine the impacts of a large dominant herbivore in the tundra ecosystem, the muskox, Ovibos moschatus, using exclosures established in a fen in high Arctic Greenland. Using weekly sampling throughout the growing season, we quantified the effects of muskox exclusion on aboveground plant biomass and on concentrations and pools of carbon and nitrogen, and...
Housing Market Activity is Associated with Disparities in Urban and Metropolitan Vegetation
01. Dezember 2018
Abstract In urban areas, the consistent and positive association between vegetation density and household income has been explained historically by either the capitalization of larger lawns and lower housing densities or landscaping and lifestyle districts that convey prestige. Yet cities with shrinking populations and rising land burdens often exhibit high vegetation density in declining neighborhoods. Because the observed associations do not directly address the causal connection between measures of social privilege and vegetation in urban landscapes, it is difficult...
Variation in Detrital Resource Stoichiometry Signals Differential Carbon to Nutrient Limitation for Stream Consumers Across Biomes
01. Dezember 2018
Abstract Stoichiometric ratios of resources and consumers have been used to predict nutrient limitation across diverse terrestrial and aquatic ecosystems. In forested headwater streams, coarse and fine benthic organic matter (CBOM, FBOM) are primary basal resources for the food web, and the distribution and quality of these organic matter resources may therefore influence patterns of secondary production and nutrient cycling within stream networks or among biomes. We measured carbon (C), nitrogen (N), and phosphorus (P) content of CBOM and FBOM and calculated their...
Characteristics of Old-Growth and Secondary Forests in Relation to Age and Typhoon Disturbance
01. Dezember 2018
Abstract Many properties of forest ecosystems, such as species composition and forest structure, naturally vary with forest age. However, in regions prone to cyclone disturbances, both forest age and cyclone severities can play a role shaping these properties. To evaluate potential effects of an altered cyclone regime on forest ecosystems, it is necessary to disentangle the roles of cyclones and forest age on different forest characteristics. In this study, we compared species composition and forest structure at plot level across sites with similar climate and...
Decline in Ecosystem δ 13 C and Mid-Successional Nitrogen Loss in a Two-Century Postglacial Chronosequence
01. Dezember 2018
Abstract Uncertainty about controls on long-term carbon (C) and nitrogen (N) balance, turnover, and isotopic composition currently limits our ability to predict ecosystem response to disturbance and landscape change. We used a two-century, postglacial chronosequence in Glacier Bay, Alaska, to explore the influence of C and N dynamics on soil and leaf stable isotopes. C dynamics were closely linked to soil hydrology, with increasing soil water retention during ecosystem development resulting in a linear decrease in foliar and soil δ13C, independent of shifts in...