scholarly journals Species losses, gains, and changes in persistent species are associated with distinct effects on ecosystem functioning in global grasslands

2022 ◽  
Author(s):  
Emma Ladouceur ◽  
Shane Blowes ◽  
Jonathan Chase ◽  
Adam Clark ◽  
Magda Garbowski ◽  
...  
Keyword(s):  
Ecosystem Functioning ◽  
Community Change ◽  
Price Equation ◽  
Ecosystem Functions ◽  
Ambient Conditions ◽  
Nutrient Inputs ◽  
Separate Species ◽  
Biomass Turnover ◽  
Local Extinctions ◽  
Biomass Loss

Global change drivers such as anthropogenic nutrient inputs simultaneously alter biodiversity, species composition, and ecosystem functions such as above ground biomass. These changes are interconnected by complex feedbacks among extinction, invasion, and shifting relative abundance. Here, we use a novel temporal application of the Price equation to separate species richness and biomass change through time and quantify the functional contributions of species that are lost, gained, and persist under ambient and experimental nutrient addition in 59 global grasslands. Under ambient conditions, compositional and biomass turnover was high, but species losses (i.e., local extinctions) were balanced by gains (i.e. colonization). Under fertilization, there was biomass loss associated with species loss. Few species were gained in fertilized conditions over time but those that were, and species that persisted, contributed to net biomass gains, outweighing biomass loss. These components of community change are associated with distinct effects on measures of ecosystem functioning.

Effects of riffle–step restoration on hyporheic zone chemistry in N-rich lowland streams

2006 ◽  
Vol 63 (1) ◽  
pp. 120-133 ◽  
Author(s):  
Tamao Kasahara ◽  
Alan R Hill
Keyword(s):  
Urban Areas ◽  
Hyporheic Zone ◽  
Stream Water ◽  
Ion Concentration ◽  
Hyporheic Exchange ◽  
Ecosystem Functions ◽  
Exchange Flow ◽  
Nutrient Inputs ◽  
Lowland Streams ◽  
Hyporheic Zones

Stream restoration projects that aim to rehabilitate ecosystem health have not considered surface–subsurface linkages, although stream water and groundwater interaction has an important role in sustaining stream ecosystem functions. The present study examined the effect of constructed riffles and a step on hyporheic exchange flow and chemistry in restored reaches of several N-rich agricultural and urban streams in southern Ontario. Hydrometric data collected from a network of piezometers and conservative tracer releases indicated that the constructed riffles and steps were effective in inducing hyporheic exchange. However, despite the use of cobbles and boulders in the riffle construction, high stream dissolved oxygen (DO) concentrations were depleted rapidly with depth into the hyporheic zones. Differences between observed and predicted nitrate concentrations based on conservative ion concentration patterns indicated that these hyporheic zones were also nitrate sinks. Zones of low hydraulic conductivity and the occurrence of interstitial fines in the restored cobble-boulder layers suggest that siltation and clogging of the streambed may reduce the downwelling of oxygen- and nitrate-rich stream water. Increases in streambed DO levels and enhancement of habitat for hyporheic fauna that result from riffle–step construction projects may only be temporary in streams that receive increased sediment and nutrient inputs from urban areas and croplands.

scholarly journals Plant traits are poor predictors of long-term ecosystem functioning

2019 ◽  
Author(s):  
Fons van der Plas ◽  
Thomas Schröder-Georgi ◽  
Alexandra Weigelt ◽  
Kathryn Barry ◽  
Sebastian Meyer ◽  
...  
Keyword(s):  
Plant Species ◽  
Ecosystem Functioning ◽  
Plant Traits ◽  
Vascular Plant ◽  
Plant Performance ◽  
Ecosystem Functions ◽  
Average Percentage ◽  
Functional Consequences ◽  
Small Set

ABSTRACTEarth is home to over 350,000 vascular plant species1 that differ in their traits in innumerable ways. Yet, a handful of functional traits can help explaining major differences among species in photosynthetic rate, growth rate, reproductive output and other aspects of plant performance2–6. A key challenge, coined “the Holy Grail” in ecology, is to upscale this understanding in order to predict how natural or anthropogenically driven changes in the identity and diversity of co-occurring plant species drive the functioning of ecosystems7, 8. Here, we analyze the extent to which 42 different ecosystem functions can be predicted by 41 plant traits in 78 experimentally manipulated grassland plots over 10 years. Despite the unprecedented number of traits analyzed, the average percentage of variation in ecosystem functioning that they jointly explained was only moderate (32.6%) within individual years, and even much lower (12.7%) across years. Most other studies linking ecosystem functioning to plant traits analyzed no more than six traits, and when including either only six random or the six most frequently studied traits in our analysis, the average percentage of explained variation in across-year ecosystem functioning dropped to 4.8%. Furthermore, different ecosystem functions were driven by different traits, with on average only 12.2% overlap in significant predictors. Thus, we did not find evidence for the existence of a small set of key traits able to explain variation in multiple ecosystem functions across years. Our results therefore suggest that there are strong limits in the extent to which we can predict the long-term functional consequences of the ongoing, rapid changes in the composition and diversity of plant communities that humanity is currently facing.

scholarly journals Elevation and Distribution of Freshwater and Sewage Canals Regulate Canopy Structure and Differentiate Hurricane Damages to a Basin Mangrove Forest

2021 ◽  
Vol 13 (17) ◽  
pp. 3387
Author(s):  
Qiong Gao ◽  
Mei Yu
Keyword(s):  
Spatial Variation ◽  
Mangrove Forest ◽  
Canopy Structure ◽  
Canopy Height ◽  
Ecosystem Functions ◽  
Strong Impact ◽  
Nutrient Inputs ◽  
Height Reduction ◽  
Lower Elevation ◽  
Crown Defoliation

The coastal mangrove forest bears important ecosystem functions and services, including the protection of shorelines and coastal communities. While coastal mangroves often suffer severe damage during storms, understanding the vulnerability and resistance of mangroves to the damage at a landscape scale is crucial for coastal mangrove management and conservation. In September 2017, two consecutive major hurricanes caused tremendous damage to the coastal mangroves in the Caribbean. By utilizing LiDAR data taken before and after the hurricanes in a basin mangrove forest in Northeast Puerto Rico, we analyzed the spatial variation of a canopy structure before the hurricanes and hurricane-induced canopy height reduction and explored possible drivers by means of spatial regressions. Regarding the canopy structure, we found that the pre-hurricane canopy height of the mangrove forest decreased with elevation and distance to the freshwater/sewage canals within the forest, and these two drivers explained 82% of variations in the mangrove canopy height. The model, thus, implies that freshwater and nutrient inputs brought by the canals tend to promote the canopy height, and mangrove trees at lower elevation are especially more advantageous. Similarly, tree densities decreased with the canopy height but increased with the elevation and the distance to the canals. We also found that this mangrove forest suffered on average a 53% canopy height reduction, reflecting mostly heavy crown defoliation and the rupture of branches. The regression, which explains 88% of spatial variation in the canopy height reduction, showed that mangroves with a higher canopy or lower density, or growing in lower elevation, or being closer to the canals suffered more damage. Our findings indicate that delivered freshwater/sewage by means of human-made canals has a strong impact on the canopy structure as well as its resistance to tropical storms. Freshwater and sewage tend to release the salinity stress and nutrient deficit and, thus, to promote the mangrove canopy height. However, the addition of freshwater and nutrients might also increase the risk of mangrove damage during the storms probably because of an altered allometry of assimilates.

scholarly journals Impairment of microbial and meiofaunal ecosystem functions linked to algal forest loss

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Silvia Bianchelli ◽  
Roberto Danovaro
Keyword(s):  
Habitat Loss ◽  
Ecosystem Functioning ◽  
Negative Impact ◽  
Ecosystem Functions ◽  
Marine Biodiversity ◽  
Forest Loss ◽  
Higher Taxa ◽  
Vulnerable Habitats ◽  
Nematode Biodiversity ◽  
Barren Grounds

AbstractHabitat loss is jeopardizing marine biodiversity. In the Mediterranean Sea, the algal forests of Cystoseira spp. form one of the most complex, productive and vulnerable shallow-water habitats. These forests are rapidly regressing with negative impact on the associated biodiversity, and potential consequences in terms of ecosystem functioning. Here, by comparing healthy Cystoseira forests and barren grounds (i.e., habitats where the macroalgal forests disappeared), we assessed the effects of habitat loss on meiofaunal and nematode biodiversity, and on some ecosystem functions (here measured in terms of prokaryotic and meiofaunal biomass). Overall, our results suggest that the loss of Cystoseira forests and the consequent barren formation is associated with the loss of meiofaunal higher taxa and a decrease of nematode biodiversity, leading to the collapse of the microbial and meiofaunal variables of ecosystem functions. We conclude that, given the very limited resilience of these ecosystems, active restoration of these vulnerable habitats is needed, in order to recover their biodiversity, ecosystem functions and associated services.

scholarly journals Linking community size structure and ecosystem functioning using metabolic theory

2012 ◽  
Vol 367 (1605) ◽  
pp. 2998-3007 ◽  
Author(s):  
Gabriel Yvon-Durocher ◽  
Andrew P. Allen
Keyword(s):  
Ecosystem Functioning ◽  
Size Structure ◽  
Ecosystem Respiration ◽  
Gross Primary Production ◽  
Research Question ◽  
Biogeochemical Cycles ◽  
Ecosystem Functions ◽  
Central Research ◽  
Metabolic Theory ◽  
Community Size

Understanding how biogeochemical cycles relate to the structure of ecological communities is a central research question in ecology. Here we approach this problem by focusing on body size, which is an easily measured species trait that has a pervasive influence on multiple aspects of community structure and ecosystem functioning. We test the predictions of a model derived from metabolic theory using data on ecosystem metabolism and community size structure. These data were collected as part of an aquatic mesocosm experiment that was designed to simulate future environmental warming. Our analyses demonstrate significant linkages between community size structure and ecosystem functioning, and the effects of warming on these links. Specifically, we show that carbon fluxes were significantly influenced by seasonal variation in temperature, and yielded activation energies remarkably similar to those predicted based on the temperature dependencies of individual-level photosynthesis and respiration. We also show that community size structure significantly influenced fluxes of ecosystem respiration and gross primary production, particularly at the annual time-scale. Assessing size structure and the factors that control it, both empirically and theoretically, therefore promises to aid in understanding links between individual organisms and biogeochemical cycles, and in predicting the responses of key ecosystem functions to future environmental change.

scholarly journals Nutrient pollution disrupts key ecosystem functions on coral reefs

2018 ◽  
Vol 285 (1880) ◽  
pp. 20172718 ◽  
Author(s):  
Nyssa J. Silbiger ◽  
Craig E. Nelson ◽  
Kristina Remple ◽  
Jessica K. Sevilla ◽  
Zachary A. Quinlan ◽  
...  
Keyword(s):  
Coral Reefs ◽  
Nutrient Addition ◽  
Ecosystem Functions ◽  
Nutrient Pollution ◽  
Global Changes ◽  
Ambient Conditions ◽  
Net Community Production ◽  
Saturation State ◽  
Indirect Response ◽  
The Impact

There is a long history of examining the impacts of nutrient pollution and pH on coral reefs. However, little is known about how these two stressors interact and influence coral reef ecosystem functioning. Using a six-week nutrient addition experiment, we measured the impact of elevated nitrate (NO − 3 ) and phosphate (PO 3− 4 ) on net community calcification (NCC) and net community production (NCP) rates of individual taxa and combined reef communities. Our study had four major outcomes: (i) NCC rates declined in response to nutrient addition in all substrate types, (ii) the mixed community switched from net calcification to net dissolution under medium and high nutrient conditions, (iii) nutrients augmented pH variability through modified photosynthesis and respiration rates, and (iv) nutrients disrupted the relationship between NCC and aragonite saturation state documented in ambient conditions. These results indicate that the negative effect of NO − 3 and PO 3− 4 addition on reef calcification is likely both a direct physiological response to nutrients and also an indirect response to a shifting pH environment from altered NCP rates. Here, we show that nutrient pollution could make reefs more vulnerable to global changes associated with ocean acidification and accelerate the predicted shift from net accretion to net erosion.

scholarly journals Fungal-bacterial diversity and microbiome complexity predict ecosystem functioning

2019 ◽  
Vol 10 (1) ◽  
Author(s):  
Cameron Wagg ◽  
Klaus Schlaeppi ◽  
Samiran Banerjee ◽  
Eiko E. Kuramae ◽  
Marcel G. A. van der Heijden
Keyword(s):  
Microbial Communities ◽  
Bacterial Communities ◽  
Ecosystem Functioning ◽  
Microbial Interactions ◽  
Soil Microbiome ◽  
Ecosystem Functions ◽  
Microbial Network ◽  
Grassland Ecosystems ◽  
Microbiome Diversity ◽  
Ecological Associations

Abstract The soil microbiome is highly diverse and comprises up to one quarter of Earth’s diversity. Yet, how such a diverse and functionally complex microbiome influences ecosystem functioning remains unclear. Here we manipulated the soil microbiome in experimental grassland ecosystems and observed that microbiome diversity and microbial network complexity positively influenced multiple ecosystem functions related to nutrient cycling (e.g. multifunctionality). Grassland microcosms with poorly developed microbial networks and reduced microbial richness had the lowest multifunctionality due to fewer taxa present that support the same function (redundancy) and lower diversity of taxa that support different functions (reduced  functional uniqueness). Moreover, different microbial taxa explained different ecosystem functions pointing to the significance of functional diversity in microbial communities. These findings indicate the importance of microbial interactions within and among fungal and bacterial communities for enhancing ecosystem performance and demonstrate that the extinction of complex ecological associations belowground can impair ecosystem functioning.

scholarly journals Predicting future invaders and future invasions

2019 ◽  
Vol 116 (16) ◽  
pp. 7905-7910 ◽  
Author(s):  
Alice Fournier ◽  
Caterina Penone ◽  
Maria Grazia Pennino ◽  
Franck Courchamp
Keyword(s):  
Papua New Guinea ◽  
Ecosystem Functioning ◽  
Species Distribution Models ◽  
Invasive Alien Species ◽  
Management Strategies ◽  
Central Africa ◽  
Invasive Ants ◽  
Distribution Models ◽  
Proactive Management ◽  
Local Extinctions

Invasive alien species are a great threat to biodiversity and human livelihoods worldwide. The most effective way to limit their impacts and costs is to prevent their introduction into new areas. Identifying invaders and invasions before their occurrence would arguably be the most efficient strategy. Here, we provide a profiling method to predict which species—with which particular ecological characteristics—will invade, and where they could invade. We illustrate our approach with ants, which are among the most detrimental invasive species, as they are responsible for declines of numerous taxa, are involved in local extinctions, disturb ecosystem functioning, and impact multiple human activities. Based on statistical profiling of 1,002 ant species from an extensive trait database, we identify 13 native ant species with an ecological profile that matches that of known invasive ants. Even though they are not currently described as such, these species are likely to become the next global invaders. We couple these predictions with species distribution models to identify the regions most at risk from the invasion of these species: Florida and Central America, Brazil, Central Africa and Madagascar, Southeast Asia, Papua New Guinea Northeast Australia, and many islands worldwide. This framework, applicable to any other taxa, represents a remarkable opportunity to implement timely and specifically shaped proactive management strategies against biological invasions.

Lotic bacterioplankton and phytoplankton community changes under dissolved organic-carbon amendment: evidence for competition for nutrients

2016 ◽  
Vol 67 (9) ◽  
pp. 1362 ◽  
Author(s):  
R. L. Carney ◽  
J. R. Seymour ◽  
D. Westhorpe ◽  
S. M. Mitrovic
Keyword(s):  
Organic Carbon ◽  
Dissolved Organic Carbon ◽  
Chlorophyll A ◽  
Phytoplankton Biomass ◽  
Bacterial Abundance ◽  
Intergenic Spacer ◽  
Community Change ◽  
Phytoplankton Production ◽  
Nutrient Inputs ◽  
Major Pathway

During periods of low river discharge, bacterial growth is typically limited by dissolved organic carbon (DOC) and is tightly regulated by phytoplankton production. However, import of allochthonous DOC into rivers by freshwater inflows may diminish bacterial reliance on phytoplankton-produced carbon, leading to competition for nitrogen (N) and phosphorus (P). To investigate phytoplankton–bacterial competition in response to allochthonous inputs, we conducted a mesocosm experiment, comparing microbial responses to the following two manipulation treatments: (1) addition of N and P, and (2) addition of a DOC and N and P. Measurement of chlorophyll-a estimated phytoplankton biomass and microscopic counts were performed to discriminate community change. Bacterial abundance was tracked using flow cytometry and community assemblages were characterised using automated ribosomal intergenic spacer analyses and 16S rRNA-amplicon sequencing. We found that bacterial abundance increased in the leachate addition, whereas chlorophyll-a was reduced and the bacterial community shifted to one dominated by heterotrophic genera, and autotrophic microbes including Synechococcus and Cyclotella increased significantly in the nutrient treatment. These observations indicated that DOC and nutrient inputs can lead to shifts in the competitive dynamics between bacteria and phytoplankton, reducing phytoplankton biomass, which may potentially shift the major pathway of carbon to higher trophic organisms, from the phytoplankton grazer chain to the microbial food web.

scholarly journals Biodiversity mediates the effects of stressors but not nutrients on litter decomposition

2020 ◽  
Author(s):  
Léa Beaumelle ◽  
Frederik De Laender ◽  
Nico Eisenhauer
Keyword(s):  
Environmental Change ◽  
Litter Decomposition ◽  
Ecosystem Functioning ◽  
Structural Equation ◽  
Environmental Changes ◽  
Meta Analysis ◽  
Biodiversity Loss ◽  
Nutrient Inputs ◽  
Biodiversity Change ◽  
Biodiversity Changes

AbstractUnderstanding the consequences of ongoing biodiversity changes for ecosystems is a pressing challenge. Controlled biodiversity-ecosystem function experiments with random biodiversity loss scenarios have demonstrated that more diverse communities usually provide higher levels of ecosystem functioning. However, it is not clear if these results predict the ecosystem consequences of environmental changes that cause non-random alterations in biodiversity and community composition. We synthesized 69 independent studies reporting 660 observations of the impacts of two pervasive drivers of global change (chemical stressors and nutrient enrichment) on animal and microbial decomposer diversity and litter decomposition. Using meta-analysis and structural equation modelling, we show that declines in decomposer diversity and abundance explain reduced litter decomposition in response to stressors but not to nutrients. While chemical stressors generally reduced biodiversity and ecosystem functioning, detrimental effects of nutrients occurred only at high levels of nutrient inputs. Thus, more intense environmental change does not always result in stronger responses, illustrating the complexity of ecosystem consequences of biodiversity change. Overall, these findings provide strong empirical evidence for significant real-world biodiversity-ecosystem functioning relationships when human activities decrease biodiversity. This highlights that the consequences of biodiversity change for ecosystems are nontrivial and depend on the kind of environmental change.

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