A new probabilistic method for quantifying n‐dimensional ecological niches and niche overlap

Ecology, Journal Year: 2014, Volume and Issue: 96(2), P. 318 - 324

Published: Oct. 23, 2014

Considerable progress has been made in the development of statistical tools to quantify trophic relationships using stable isotope ratios, including that address size and overlap isotopic niches. We build upon recent propose a new probabilistic method for determining niche region pairwise can be extended beyond two dimensions, provides directional estimates overlap, accounts species-specific distributions space, and, unlike geometric methods, produces consistent unique bivariate projections multivariate data. define (NR) as given 95% (or user-defined a) probability space. Overlap is calculated an individual from species A found N(R) B. Uncertainty accounted Bayesian framework, only aspect methodology depends on sample size. Application illustrated with three-dimensional data, but practitioners could use any continuous indicator ecological number dimensions. suggest this represents advance our ability compare niches way more Hutchinson's concept "n-dimensional hypervolume".

Language: Английский

---

Uncovering trophic positions and food resources of soil animals using bulk natural stable isotope composition

Biological reviews/Biological reviews of the Cambridge Philosophical Society, Journal Year: 2018, Volume and Issue: 94(1), P. 37 - 59

Published: June 19, 2018

Despite the major importance of soil biota in nutrient and energy fluxes, interactions food webs are poorly understood. Here we provide an overview recent advances uncovering trophic structure using natural variations stable isotope ratios. We discuss approaches application, normalization interpretation ratios along with methodological pitfalls. Analysis published data from temperate forest ecosystems is used to outline emerging concepts perspectives web research. In contrast aboveground aquatic webs, fractionation at basal level detrital large for carbon small nitrogen isotopes. Virtually all animals enriched 13 C as compared plant litter. This 'detrital shift' likely reflects preferential uptake C-enriched microbial biomass underlines microorganisms, dead material, a resource animal community. Soil organic matter 15 N relative leaf Decomposers inhabiting mineral layers therefore might be resulting overlap between soil-dwelling detritivores litter-dwelling predators. By contrast, content varies little upper litter soil, suggesting that they rely on similar resources, i.e. decomposed matter. Comparing vertical gradients resources can valuable tool assess dynamics soil. As indicated by composition, direct feeding living material well mycorrhizal fungi rare among invertebrates. Plant taken up predominantly saprotrophic microorganisms channelled higher levels web. However, photoautotrophic non-vascular plants may play important role fuelling webs. The niche most high-rank taxa spans least two levels, implying use wide range resources. Therefore, identify species links low-rank taxonomic identification required. strategies, composition groups differences Different predators decomposers linked different pools functional roles indicating niches communities phylogenetically structured. During last decades studies analysis have elucidated communities, clarified revealed above- belowground ecosystem compartments. Extending wider organisms, including microfauna, larger array provides perspective comprehensive understanding functioning

Language: Английский

---

A rapid spread of the stony coral tissue loss disease outbreak in the Mexican Caribbean

PeerJ, Journal Year: 2019, Volume and Issue: 7, P. e8069 - e8069

Published: Nov. 26, 2019

Caribbean reef corals have experienced unprecedented declines from climate change, anthropogenic stressors and infectious diseases in recent decades. Since 2014, a highly lethal, new disease, called stony coral tissue loss has impacted many reef-coral species Florida. During the summer of 2018, we noticed an anomalously high disease prevalence affecting different northern portion Mexican Caribbean. We assessed severity this outbreak 2018/2019 using AGRRA protocol to survey 82 sites across Then, subset 14 sites, detailed information before (2016/2017) explore consequences on condition composition communities. Our findings show that already spread entire region by similar (with patterns) those previously described for However, observed great variability mortality was not attributable any geographical gradient. Using long-term data, determined there is no evidence such anywhere which suggests afflicted within few months. The analysis contained pre-outbreak showed event considerably increased severely changed structure communities region. Given lethality number susceptible species, encourage researchers, managers stakeholders Western Atlantic accord it highest priority near future.

Language: Английский

---

Microplastics in freshwater fishes: Occurrence, impacts and future perspectives

Fish and Fisheries, Journal Year: 2021, Volume and Issue: 22(3), P. 467 - 488

Published: Jan. 29, 2021

Abstract Microplastics (MPs) are small, plastic particles of various shapes, sizes and polymers. Although well studied in marine systems, their roles importance freshwater environments remain uncertain. Nevertheless, the restricted ranges variable traits fishes result communities being important receptors strong bioindicators MP pollution. Here, current knowledge on MPs is synthesized, along with development recommendations for future research sample processing. commonly ingested passively taken up by numerous fishes, ingestion patterns often related to individual (e.g. body size, trophic level) environmental factors local urbanization, habitat features). Controlled exposure studies highlight effects fish physiology, biochemistry behaviour that complex, unpredictable, species‐specific nonlinear respect dose–response relationships. Egestion typically rapid effective, although a particular shape and/or size may remain, or translocate across intestinal wall other organs via blood. Regarding studies, there need understand interactions pollution anthropogenic stressors warming, eutrophication), concomitant requirement increase complexity enable impact assessment at population, community ecosystem levels, determine whether consequences processes, such as parasite transmission, where could vector parasites infection susceptibility. This will extent which can be considered major stressor freshwaters this era global change.

Language: Английский

---

Quantifying the multiple facets of isotopic diversity: New metrics for stable isotope ecology

Ecological Indicators, Journal Year: 2015, Volume and Issue: 56, P. 152 - 160

Published: May 15, 2015

Language: Английский

---

Experimental Evidence from Causal Criteria Analysis for the Effects of Common CarpCyprinus carpioon Freshwater Ecosystems: A Global Perspective

Reviews in Fisheries Science & Aquaculture, Journal Year: 2015, Volume and Issue: 23(3), P. 253 - 290

Published: July 3, 2015

As the most widely distributed freshwater fish worldwide, common carp Cyprinus carpio can be either invasive or "naturalized" in areas of introduction. This leads to different levels perception regarding species' role ecosystems, with experimental research focusing on its "middle-out" impacts overall function limnological processes. At same time, large scales at which dynamics operate may severely limit validity laboratory and, oftentimes, field experiments extrapolating results real-world ecosystems. In this study, 129 laboratory, field, and "natural" were systematically reviewed through causal criteria analysis, within an historical/biogeographical risk-assessment context. Of 19 countries where conducted, only 4 considered as "low risk" one "no risk," other being "medium" "high risk." Experimental findings from 373 component-wise assessments supported framework effects water quality, vegetation, invertebrates, vertebrates, latter including also amphibians waterfowl, previously unreported. Stronger evidence was provided by natural relative experiments, reflecting reductionism latter. Critical biomass for impact highly dependent setup, even though threshold ≈200 kg ha−1 under conditions recent findings. Management should reflect level current potential risk posed species distribution, thereby accounting projections further spread but unsuccessful colonization. Future experimentation favor a holistic→reductionist over reductionist→holistic approach.

Language: Английский

---

Stable isotope‐based community metrics as a tool to identify patterns in food web structure in east African estuaries

Functional Ecology, Journal Year: 2013, Volume and Issue: 28(1), P. 270 - 282

Published: July 8, 2013

Summary Quantitative tools to describe biological communities are important for conservation and ecological management. The analysis of trophic structure can be used quantitatively communities. Stable isotope is useful organization, but statistical models that allow the identification general patterns comparisons between systems/sampling periods have only recently been developed. Here, stable isotope‐based B ayesian community‐wide metrics investigate in five estuaries differ size, sediment yield catchment vegetation cover ( C 3/ 4): Z ambezi M ozambique, T ana K enya R ianila, etsiboka P angalanes anal (sampled at A mbila) adagascar. Primary producers, invertebrates fish different ecologies were sampled each estuary before after 2010–2011 wet season. Trophic length, estimated based on δ 15 N , varied 3·6 4·7 levels ambezi) did not vary seasonally any estuary. differed most mbila, where diversity redundancy lower than other estuaries. Among four open estuaries, 4‐dominated) had ianila 3‐dominated), probably due high loads suspended sediment, which limited availability aquatic sources. There was seasonality mbila etsiboka, as increased decreased from prewet postwet For this resulted higher variability sources season, allowed diets diversify. productivity low, likely a greater input terrestrial material during comparative detect identify differences/similarities organization related environmental conditions. However, more widespread application these approaches across faunal contrasting ecosystems required robust large‐scale structure. approach here may also find comparing food web impacts or monitoring recovery rehabilitation.

Language: Английский

---

Niche differentiation among invasive crayfish and their impacts on ecosystem structure and functioning

Freshwater Biology, Journal Year: 2014, Volume and Issue: 59(6), P. 1123 - 1135

Published: Feb. 16, 2014

Summary Many aquatic ecosystems sustain multiple invasive species and interactions among them have important implications for ecosystem structure functioning. Here, we examine two pairs of crayfish because their close proximity thus chance sympatric populations in the near future within Thames catchment, U.K. (signal, P acifastacus leniusculus virile crayfish, O rconectes virilis a river system; red swamp, Procambarus clarkii Turkish A stacus leptodactylus found suite ponds). We address questions: do occupy smaller niche than allopatric counterparts due to potential resource competition? amplify or mitigate one another's impacts on ecosystem? Two fully factorial mesocosm experiments (one each pair) were used investigate diet impact benthic invertebrate community structure, algal standing stock leaf litter decomposition rates populations, compared with crayfish‐free control. stable isotope analysis mesocosms catchment. Isotopic width did not vary significantly between experiments, isotopic partitioning all wild suggests invaders can coexist. All four altered but differing functional effects, often mediated via trophic cascades. Red swamp predation upon snails evidently promoted reduction grazing pressure. However, cascade whereby consumed native shredders, causing net decomposition, was decoupled by signal since they directly moderated trickle when sympatry respectively. Benthic predator abundance reduced independently allopatry, indicating an amplified effect overall sympatry. Our results suggest that combined invasions reflect either additive independent effect, which is greater sum impacts. lack general pattern effects makes any management strategy more complex.

Language: Английский

---

Patterns of trophic niche divergence between invasive and native fishes in wild communities are predictable from mesocosm studies

Journal of Animal Ecology, Journal Year: 2015, Volume and Issue: 84(4), P. 1071 - 1080

Published: March 3, 2015

Ecological theory attempts to predict how impacts for native species arise from biological invasions. A fundamental question centres on the feeding interactions of invasive and species: whether invasion will result in increased interspecific competition, which would negative consequences competing species, or trophic niche divergence, facilitate invader's integration into community their coexistence with species. Here, a highly fish, topmouth gudgeon Pseudorasbora parva, three functionally similar fishes were studied determine patterns either overlap divergence detected mesocosm experiments apparent between at larger spatial scales. Using stable isotope analysis, relationships assessed initially mesocosms (1000 L) then small ponds (<400 m(2) ) large (>600 ). In mesocosms, consistent pattern was evident sympatric fishes, niches shifting further apart isotopic space than suggested allopatry, revealing that sharing food resources limited. Sympatric P. parva also had smaller allopatric populations. eight where coexisted several years least one fish used strong differentiation apparent, always lower position other as occurred mesocosms. Where these within more complex communities ponds, evidence differentiation. Aspects ecological those experiments. Their resulted niches, partly due reduced widths when sympatry facilitating invaded ecosystems. Our study highlights utility controlled studies predicting can develop introductions non-native ecosystems

Language: Английский

---

Carbon stable isotopes suggest that hippopotamus‐vectored nutrients subsidize aquatic consumers in an East African river

Ecosphere, Journal Year: 2015, Volume and Issue: 6(4), P. 1 - 11

Published: April 1, 2015

The common hippopotamus, Hippopotamus amphibius , transports millions of tons organic matter annually from its terrestrial feeding grounds into aquatic habitats. We evaluated whether carbon stable isotopes (δ 13 C) can be used as tracers for determining H. ‐vectored allochthonous material is utilized by consumers. Two approaches were employed to make this determination: (1) lab‐based trials where omnivorous river fish fed a dung diet and (2) field sampling insects in pools with without . Lab revealed that exclusively exhibited significantly more positive δ C values than not dung. Fish sampled pool decades also at the end dry season an upstream ‐free reference pool. these same wet (high flow) showed no significant differences values, suggesting higher flows reduced retention use subsidies. These data provide preliminary evidence may useful, certain contexts, quantifying importance matter.

Language: Английский

---