Ecosystem Ecology Research Articles

Assessment of ecosystem trophodynamic power: A model based on the power equation for an oscillating string

The emergence of organic biophysics of ecosystems (OBEC: an interdisciplinary approach supported by thirteen previous articles in order to get a non-contingent explanation of ecosystem dynamics) may close the gap between the foundation of ecosystem ecology in classical thermodynamics and the paradoxical fact that conventional thermostatistics is currently regarded as useless to explain ecosystem functioning. The measurement of eco-kinetic energy (Eep) was the first step of OBEC. However, Eep assesses trophic energy as a stock rather than a flow. In order to normalize the above-mentioned situation, this article proposes a model to assess the average trophodynamic power (Pt,avg: flow of eco-kinetic energy per space-time unit) of ecosystems by extrapolating the equation of average power for an oscillating string. With such a goal, we quantified the power associated to oscillations of the difference between the standardized values of species richness and evenness per value class of several species diversity distributions. In order to validate if Pt, avg has a reliable meaning, Pt, avg was correlated with a wide spectrum of biotic and abiotic environmental factors, every of them with a well-known independent meaning. We herein use field data from three databases (inland water zooplankton, leaf litter invertebrates, and ruderal vegetation) to test the reliability of this model. Our results showed that Pt,avg is correlated in a significant way, either positively or negatively, with important environmental factors. As a result, it is feasible to use the proposed equation as a reliable tool to measure the intensity of eco-kinetic energy flow under stationary and non-stationary conditions. This proposal has advantages in comparison with conventional methods (e.g.: standing biomass, carbon fixation), and it is useful for monitoring anthropogenic impacts on ecosystem metabolism.

The state of the world’s mangroves in the 21st century under climate change

Concerted mangrove research and rehabilitation efforts over the last several decades have prompted a better understanding of the important ecosystem attributes worthy of protection and a better conservation ethic toward mangrove wetlands globally. While mangroves continue to be degraded and lost in specific regions, conservation initiatives, rehabilitation efforts, natural regeneration, and climate range expansion have promoted gains in other areas, ultimately serving to curb the high mangrove habitat loss statistics from the doom and gloom of the 1980s. We highlight those trends in this article and introduce this special issue of Hydrobiologia dedicated to the important and recurring Mangrove and Macrobenthos Meeting. This collection of papers represents studies presented at the fourth such meeting (MMM4) held in St. Augustine, Florida, USA, on July 18–22, 2016. Our intent is to provide a balanced message about the global state of mangrove wetlands by describing recent reductions in net mangrove area losses and highlighting primary research studies presented at MMM4 through a collection of papers. These papers serve not only to highlight on-going global research advancements, but also provide an overview of the vast amount of data on mangrove ecosystem ecology, biology and rehabilitation that emphasizes the uniqueness of the mangrove community.

The combined effects of ocean warming and acidification on shallow-water meiofaunal assemblages

Climate change due to increased anthropogenic CO2 in the atmosphere is causing an increase in seawater temperatures referred to as ocean warming and a decrease in seawater pH, referred to as ocean acidification. The meiofauna play an important role in the ecology of marine ecosystems and the functions they provide. Using microcosms, meiofaunal assemblages were exposed to two temperatures (15 and 19 °C) and two pHs (pCO2 of 400 and 1000 ppm), both individually and in combination, for a period of 90 days. The hypothesis that increased temperature will increase meiofaunal abundance was not supported. The hypothesis that a reduced pH will reduce meiofaunal abundance and species richness was supported. The combination of future conditions of temperature and pH (19 °C and pCO2 of 1000 ppm) did not affect overall abundance but the structure of the nematode assemblage changed becoming dominated by a few opportunistic species.

Thermostatistical distribution of a trophic energy proxy: Extension for modelling energy pyramids at the inter-taxocene scale and under non-stationary conditions

The theory of food chains, and therefore the assembly and modifications of trophic pyramids depending on environmental influences, is an essential part of modern ecosystem ecology. A general model of energy pyramids based on a fruitful but simple analytical connection between ecology and conventional physics has been proposed by Rodríguez et al. (2015a). However, this model has several drawbacks. Among them: it has only been tested for isolated taxocenes and under stationary ecological conditions (SEC). Besides, it has not been tested if the internal distribution of typical species groups within the obtained pyramids follows the expected pattern according to the well-known trophic habits of these typical groups of species. This article starts with a brief summary of the most relevant drawbacks of our conventional point of view about trophic pyramids in order to highlight the differences, as well as the advantageous coincidences, of the above-mentioned new model in comparison with our orthodox point of view about trophic pyramids. This summary connects with a description of the obstacles that should be surpassed in order to develop a more general model (i) valid at the inter-taxocene scale and (ii) fully useful to model systems under non-stationary ecological conditions (NSEC). The article proposes two simple mathematical modifications of the original model in order to achieve items (i) and (ii). In subsequent sections, the effectiveness of these modifications is tested by using field data from 25 samplings belonging to 6 different taxocenes, by including a majority of zooplankton data from a human-made highly eutrophic reservoir (Acton Lake; Hueston Woods State Park, Ohio, U.S.A.) with frequent and contingent episodes of NSEC. According to our results, it is not possible to reject either the hypothesis about the validity of modifying the original equation to model ecosystems as a whole under NSEC or the hypothesis that typical species groups follow a distribution within their respective pyramid in agreement with the expected pattern according to their trophic habits. In summary, this article is an additional step in favor of the usefulness of rescuing and expanding the original epistemological roots of ecosystem ecology in connection with conventional physics.

Advancing research on animal-transported subsidies by integrating animal movement and ecosystem modelling.

Connections between ecosystems via animals (active subsidies) support ecosystem services and contribute to numerous ecological effects. Thus, the ability to predict the spatial distribution of active subsidies would be useful for ecology and conservation. Previous work modelling active subsidies focused on implicit space or static distributions, which treat passive and active subsidies similarly. Active subsidies are fundamentally different from passive subsidies, because animals can respond to the process of subsidy deposition and ecosystem changes caused by subsidy deposition. We propose addressing this disparity by integrating animal movement and ecosystem ecology to advance active subsidy investigations, make more accurate predictions of subsidy spatial distributions, and enable a mechanistic understanding of subsidy spatial distributions. We review selected quantitative techniques that could be used to accomplish integration and lead to novel insights. The ultimate objective for these types of studies is predictions of subsidy spatial distributions from characteristics of the subsidy and the movement strategy employed by animals that transport subsidies. These advances will be critical in informing the management of ecosystem services, species conservation and ecosystem degradation related to active subsidies.

Global Change and the Soil Microbiome: A Human-Health Perspective

The importance of the gut and the soil microbiomes as determinants of human and ecosystem health, respectively, is gaining rapid acceptation in the medical and ecological literatures. This suggests that there is a wealth of highly transferable knowledge about the microbial ecology of human and non-human ecosystems that is currently being generated in parallel, but mostly in isolation from one another. I suggest that effectively sharing this knowledge could greatly help at more efficiently understanding and restoring human health and the functioning of ecosystems, which are currently under wide-spread pressure. I illustrate this by comparing the effects of nitrogen deposition on ecosystem carbon sequestration with unhealthy dietary habits and human disease. The deposition of N, a key nutrient for plant growth, may increase carbon sequestration (equivalent to obesity) through several mechanisms, including a reduction in the ability of soil microbes to process organic matter, which some argue could help mitigate climate change. However, this usually results in a degradation of ecosystem health and, thus, cannot represent a real solution. Similarly, human obesity is linked to an alteration of the composition and functioning of microbial communities inhabiting the gut, which is often attributed to unhealthy dietary habits, including ingesting high amounts of simple sugars and processed foods. Finally, I advocate for the explicit recognition of the many commonalities between the functioning of the gut and ecosystems and a broader multidisciplinary collaboration among experts in ecology and human health, including the engineering of soil microbial communities designed ad-hoc to restore ecosystem health.

Spatial evolution of URNCL and response of ecological security: a case study on Foshan City

As a global event, urbanization will bring long-term effects to the supporting systems and ecosystem services of the whole world. The concept of Urban and Rural Non-construction Land (URNCL) is proposed based on ecological security. It is a spatial response to facing the grand challenge of resources and environmental and a demand to achieve sustainable development in rapid urbanizing regions. The paper carries out quantificationally and systematically comprehensive research of spatial evolution of URNCL and response of ecological security of Foshan city (ecological factor and ecosystem service) based on integrating multiple data sources including remote sensing data, land-use classification data, relevant statistical data and field survey and monitoring data and introducing remote sensing analysis methods, geographic information systems spatial analysis methods and mathematical model methods.

Measuring the effects of reduced snow cover on Australia's alpine arthropods

AbstractSnow is one of the most important factors in the ecology of alpine ecosystems. In Australia, both the depth and duration of snow cover have declined significantly in recent decades and this trend is projected to continue with global warming. Many small arthropods remain active throughout the winter, within a space beneath the snowpack (subnivean) where the snow's insulation creates a thermally stable environment. Using field surveys and experimental manipulation of snow depth at two locations in the Australian alpine region, we explored the diversity of winter‐active arthropods and their response to reduced snow. Individuals from 18 arthropod Orders were detected beneath the snow during winter, with Collembola, Araneae, Acari and Coleoptera accounting for 95–98% of the individuals collected. The subnivean taxa represented a distinct subset of those active outside the winter months. Removal of the snow layer increased daily temperature fluctuations, increased the number of days below freezing and raised the mean surface temperatures. Community composition was altered by snow removal, driven by changes in the numbers of two abundant springtail taxa at each location. We found a strong reduction in the abundances of both taxa at one study site, and contrasting responses (one strong positive and one strong negative) to snow removal at the second study site. Subnivean arthropod communities in Australia thus appear sensitive to snow conditions at small spatial scales.

Microbial ecology of mountain glacier ecosystems: biodiversity, ecological connections and implications of a warming climate.

Glacier ecosystems are teeming with life on, beneath, and to a lesser degree, within their icy masses. This conclusion largely stems from polar research, with less attention paid to mountain glaciers that overlap environmentally and ecologically with their polar counterparts in some ways, but diverge in others. One difference lies in the susceptibility of mountain glaciers to the near-term threat of climate change, as they tend to be much smaller in both area and volume. Moreover, mountain glaciers are typically steeper, more dependent upon basal sliding for movement, and experience higher seasonal precipitation. Here, we provide a modern synthesis of the microbial ecology of mountain glacier ecosystems, and particularly those at low- to mid-latitudes. We focus on five ecological zones: the supraglacial surface, englacial interior, subglacial bedrock-ice interface, proglacial streams and glacier forefields. For each, we discuss the role of microbiota in biogeochemical cycling and outline ecological and hydrological connections among zones, underscoring the interconnected nature of these ecosystems. Collectively, we highlight the need to: better document the biodiversity and functional roles of mountain glacier microbiota; describe the ecological implications of rapid glacial retreat under climate change and resolve the relative contributions of ecological zones to broader ecosystem function.

湖沼生態系に及ぼす環境変化の化学量効果(L3 生態系のなかの生物群集 : 生物多様性と生態系機能の視点から)( 日本生態学会創立50周年記念大会基調シンポジウム)

湖沼生態系に及ぼす環境変化の化学量効果(L3 生態系のなかの生物群集 : 生物多様性と生態系機能の視点から)( 日本生態学会創立50周年記念大会基調シンポジウム)

岩礁潮間帯における海藻の種多様性に及ぼす栄養塩と植食の複合的影響(L3 生態系のなかの生物群集 : 生物多様性と生態系機能の視点から)( 日本生態学会創立50周年記念大会基調シンポジウム)

岩礁潮間帯における海藻の種多様性に及ぼす栄養塩と植食の複合的影響(L3 生態系のなかの生物群集 : 生物多様性と生態系機能の視点から)( 日本生態学会創立50周年記念大会基調シンポジウム)

Long-term field studies of elephants: understanding the ecology and conservation of a long-lived ecosystem engineer

Long-term field studies of elephants: understanding the ecology and conservation of a long-lived ecosystem engineer

Top-down control of carbon sequestration: grazing affects microbial structure and function in salt marsh soils.

Tidal wetlands have been increasingly recognized as long-term carbon sinks in recent years. Work on carbon sequestration and decomposition processes in tidal wetlands focused so far mainly on effects of global-change factors such as sea-level rise and increasing temperatures. However, little is known about effects of land use, such as livestock grazing, on organic matter decomposition and ultimately carbon sequestration. The present work aims at understanding the mechanisms by which large herbivores can affect organic matter decomposition in tidal wetlands. This was achieved by studying both direct animal-microbe interactions and indirect animal-plant-microbe interactions in grazed and ungrazed areas of two long-term experimental field sites at the German North Sea coast. We assessed bacterial and fungal gene abundance using quantitative PCR, as well as the activity of microbial exo-enzymes by conducting fluorometric assays. We demonstrate that grazing can have a profound impact on the microbial community structure of tidal wetland soils, by consistently increasing the fungi-to-bacteria ratio by 38-42%, and therefore potentially exerts important control over carbon turnover and sequestration. The observed shift in the microbial community was primarily driven by organic matter source, with higher contributions of recalcitrant autochthonous (terrestrial) vs. easily degradable allochthonous (marine) sources in grazed areas favoring relative fungal abundance. We propose a novel and indirect form of animal-plant-microbe interaction: top-down control of aboveground vegetation structure determines the capacity of allochthonous organic matter trapping during flooding and thus the structure of the microbial community. Furthermore, our data provide the first evidence that grazing slows down microbial exo-enzyme activity and thus decomposition through changes in soil redox chemistry. Activities of enzymes involved in C cycling were reduced by 28-40%, while activities of enzymes involved in N cycling were not consistently affected by grazing. It remains unclear if this is a trampling-driven direct grazing effect, as hypothesized in earlier studies, or if the effect on redox chemistry is plant mediated and thus indirect. This study improves our process-level understanding of how grazing can affect the microbial ecology and biogeochemistry of semi-terrestrial ecosystems that may help explain and predict differences in C turnover and sequestration rates between grazed and ungrazed systems.

Consecuencias de la deposición de nitrógeno sobre la biodiversidad y el funcionamiento de los ecosistemas terrestres: Una aproximación general desde la ecología de ecosistemas

Ochoa-Hueso, R. 2017. Consequences of nitrogen deposition on biodiversity and functioning of terrestrial ecosystems: An ecosystems ecology approach. Ecosistemas 26(1): 25-36. Doi.:10.7818/ECOS.2017.26-1.05 Nitrogen (N) deposition is one of the main five environmental change drivers that are causing a global biodiversity loss, as well as the disruption of the ecological interactions that ensure a correct ecosystem functioning. Nitrogen deposition is predicted to stabilize or even decrease in many parts of Europe and the US due to control strategies and greener technologies, whereas it will keep increasing in many areas of Asia, India and South America, which harbor some of the most valuable ecosystems, including many unique global biodiversity hotspots. In this review article, I will summarize the main effects of N deposition on several biological groups that typically define all terrestrial ecosystems (microorganisms, cryptogams, vascular plants and invertebrates), as well as on the physicochemical properties of soils that, in turn, exert a key influence on the abundance, composition and activity of the organisms that live on them. Finally, I will defend that only through highly integrated studies that jointly consider the multitrophic biodiversity and ecological interactions, thus embracing the inherent complexity of ecosystems that critically determines the realization of emergent properties key for their functioning, we will reach a full understanding of the consequences of N deposition on the ability of our ecosystems to provide key ecosystem services on which our societies depend.

Exploring the analytical consequences of ecological subjects unwittingly neglected by the mainstream of evolutionary thought

The Darwinian interpretation (Di) of evolutionary process, and its subsequent development in the form of modern evolutionary synthesis (MES), plays a paradigmatic role in the mainstream biological thought. However, the main role in the improvement from Di to MES has depended on population genetics. Conventional ecosystem ecology has added relatively few specific insights to this endeavor in spite of the well-known combined selective influence from environment. This article integrates i) recent findings in genetics (i.e.: evolutionary capacitance); ii) orthodox topics as well as recent results from a large set of models in ecosystem ecology which have recently been encompassed under the term “organic biophysics of ecosystem”; and iii) an epistemological analysis of the origin of On the Origin of Species… by reaching four main particular conclusions: (a) Despite the contemporary recognition that any kind of interspecific relationship has an evolutionary influence, the analytical emphasis of Di and MES on competition has been unwittingly oversized because of the paradoxical manner in which mutualism can emerge as an essential evolutionary force starting from competition, being this an unpublished topic that is analyzed in this manuscript by the first time. This link between two interspecific relationships that seem opposite to each other at the first glance is based on quantum effects that are totally unknown in conventional evolutionary theory due to its bias in favor of genetics, neglecting ecological considerations by contrast. (b) A holistic combination of ecological, genetic and evolutionary insights at the ecosystem level additionally confirms that the analytical role of evolutionary gradualism has also been oversized. (c) The main criterion of evolutionary success conventionally applied by Di and MES should be modified given that: (d) the preferential direction of evolutionary process theoretically proposed by Di and MES does not match with the direction of spontaneous development of natural ecosystems. The final section of this manuscript explains that these four critical outcomes in regard to Di and MES seem to have their root in epistemological inaccuracies involved in the origin of On the Origin of Species…that have been passed from generation to generation without being subjected to interdisciplinary scrutiny. This article showcases the need to review some of the foundational principles of Di and MES before building a “new floor” (i.e.: the extended evolutionary synthesis) supported on our current perspective about the evolutionary process. So, contrastingly with the genocentric nature of conventional evolutionary theory, large sections of our current evolutionary thought could change if we take into account some old results, as well as some recent ones, achieved by means of interdisciplinary approaches. In summary, this article concludes that the MES, despite its correct structure in essential points, could reach a significantly more complete epistemological condition than its current state if we add some fundamental results from ecosystem ecology that have been unwittingly neglected so far.

Hydrological-niche models predict water plant functional group distributions in diverse wetland types.

Human use of water resources threatens environmental water supplies. If resource managers are to develop policies that avoid unacceptable ecological impacts, some means to predict ecosystem response to changes in water availability is necessary. This is difficult to achieve at spatial scales relevant for water resource management because of the high natural variability in ecosystem hydrology and ecology. Water plant functional groups classify species with similar hydrological niche preferences together, allowing a qualitative means to generalize community responses to changes in hydrology. We tested the potential for functional groups in making quantitative prediction of water plant functional group distributions across diverse wetland types over a large geographical extent. We sampled wetlands covering a broad range of hydrogeomorphic and salinity conditions in South Australia, collecting both hydrological and floristic data from 687 quadrats across 28 wetland hydrological gradients. We built hydrological-niche models for eight water plant functional groups using a range of candidate models combining different surface inundation metrics. We then tested the predictive performance of top-ranked individual and averaged models for each functional group. Cross validation showed that models achieved acceptable predictive performance, with correct classification rates in the range 0.68-0.95. Model predictions can be made at any spatial scale that hydrological data are available and could be implemented in a geographical information system. We show the response of water plant functional groups to inundation is consistent enough across diverse wetland types to quantify the probability of hydrological impacts over regional spatial scales.

Book Review: Microbe, Second Edition

Book Review: Microbe, Second Edition

Plant–insect interactions: the role of ecological stoichiometry

The energy budget of organisms is a primary factor used to generate hypotheses in ecosystem ecology and evolutionary theory. Therefore, previous studies have focused on the energy costs and benefits of adaptations, the efficiency of energy acquisition and investment, and energy budget limitations. The maintenance of stoichiometric balance is equally important because inconsistency between the chemical composition of the consumer’s tissues and that of its food sources strongly affects the major life-history traits of the consumer and may influence the consumer’s fitness and shape plant–herbivore interactions. In this short review, the framework of ecological stoichiometry is introduced, focusing on plant–insect interactions in terrestrial ecosystems. The use of the trophic stoichiometric ratio (TSR) index is presented as a useful tool for indicating the chemical elements that are scarce in food and have the potential to limit the growth and development of herbivores, thereby influencing plant – herbivorous insect interactions. As an example, the elemental composition and stoichiometry of a pollen consumer (mason bee <em>Osmia bicornis</em>) and its preferred pollen are compared. The growth and development of <em>O. bicornis</em> may be colimited by the scarcity of K, Na, and N in pollen, whereas the development of the cocoon might be colimited by the scarcity of P, Mg, K, Na, Zn, Ca, and N. A literature review of the elemental composition of pollen shows high taxonomical variability in the concentrations of bee-limiting elements. The optimized collection of pollen species based on the elemental composition may represent a strategy used by bees to overcome stoichiometric mismatches, influencing their interactions with plants. It is concluded that the dependence of life-history traits on food stoichiometry should be considered when discussing life history evolution and plant–herbivore interactions. The TSR index may serve as a convenient and powerful tool in studies investigating plant-insect interactions.

A Modest Proposal for Unifying Macroevolution and Ecosystem Ecology.

A Modest Proposal for Unifying Macroevolution and Ecosystem Ecology.

Genetic and biochemical characterization of yeasts isolated from Antarctic soil samples

The Polish Arctowski Station is situated in the maritime Antarctic on the western shore of Admiralty Bay and encompasses terrestrial habitats which are not permanently covered by ice, in contrast to more than 90% of the island’s surface area. Over the past several decades, studies exploring the soils of those habitats have revealed a considerable diversity of bacteria, filamentous fungi, and, to a lesser extent, yeasts; however, characterization of this complex microbiome, especially at the molecular level, is still far from satisfactory. The isolates were assigned to their respective genera and species based on genetic analysis of the D1/D2 and ITS1-5.8S-ITS2 regions of rDNA. In the studied soil samples, the most abundant microorganisms belonged to the genera Cryptococcus, Rhodotorula, and Debaryomyces. Physiological and biochemical analysis of Cryptococcus gilvescens (pro tempore Goffeauzyma gilvescens) and Rhodotorula mucilaginosa showed only a limited level of intraspecies diversity. Cellular DNA content and karyotypes were determined using flow cytometry and pulsed-field gel electrophoresis for several selected strains. For the first time, genome size and electrophoretic karyotypes were investigated in C. gilvescens (pro tem G. gilvescens), Cryptococcus saitoi (pro tem Naganishia globosa), Cryptococcus gastricus (pro tem Goffeauzyma gastrica), and Cryptococcus albidus (pro tem Naganishia albida). In addition, plate tests showed Antarctic yeasts to be a potential source of biotechnologically important enzymes. This study in biodiversity, presenting physiological and molecular characterization of psychrotolerant yeast strains isolated from the soils of western Admiralty Bay, contributes to a better understanding of the microbial ecology of this unique ecosystem.