Trait‐based life strategies, ecological niches, and niche overlap in the nekton of the data‐poor Mediterranean Sea

Environmental conditions can shape genetic and morphological divergence. Release of new habitats during historical environmental changes was a major driver of evolutionary diversification. Here, forces shaping population structure and ecotype differentiation (‘pelagic’ and ‘coastal’) of bottlenose dolphins in the North-east Atlantic were investigated using complementary evolutionary and ecological approaches. Inference of population demographic history using approximate Bayesian computation indicated that coastal populations were likely founded by the Atlantic pelagic population after the Last Glacial Maxima probably as a result of newly available coastal ecological niches. Pelagic dolphins from the Atlantic and the Mediterranean Sea likely diverged during a period of high productivity in the Mediterranean Sea. Genetic differentiation between coastal and pelagic ecotypes may be maintained by niche specializations, as indicated by stable isotope and stomach content analyses, and social behaviour. The two ecotypes were only weakly morphologically segregated in contrast to other parts of the World Ocean. This may be linked to weak contrasts between coastal and pelagic habitats and/or a relatively recent divergence. We suggest that ecological opportunity to specialize is a major driver of genetic and morphological divergence. Combining genetic, ecological and morphological approaches is essential to understanding the population structure of mobile and cryptic species.

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High niche overlap between two successfully coexisting pairs of Lake Malawi cichlid fishes

Canadian Journal of Fisheries and Aquatic Sciences ◽

10.1139/f09-023 ◽

2009 ◽

Vol 66 (4) ◽

pp. 579-588 ◽

Cited By ~ 27

Author(s):

Christopher H. Martin ◽

Martin J. Genner

Keyword(s):

Resource Availability ◽

Niche Overlap ◽

Lake Malawi ◽

Resource Scarcity ◽

Ecological Niches ◽

Similar Species ◽

Dietary Overlap ◽

Resource Abundance ◽

Species Pairs ◽

Foraging Rate

Many species in high-diversity assemblages appear to coexist in similar ecological niches. It has been proposed that interspecific resource partitioning in these assemblages may only occur during periods of resource scarcity. We tested this hypothesis by measuring resource abundance, dietary overlap, foraging rate, and territoriality in a Lake Malawi rock cichlid assemblage over a period of 1 year. Our study examined two pairs of morphologically similar species, with each pair comprising one native species and one invader species that has successfully established after being translocated from another region of the lake. All four species changed their diet and foraging rate in response to seasonal variation in resource abundance. However, dietary overlap within both species pairs remained high in all seasons and was not influenced by resource availability. Similarly, territoriality did not decline during periods of low resource availability, suggesting no decrease in the strength of interspecific competition. These data suggest that these species pairs are successfully coexisting despite substantial niche overlap during resource scarcity. Thus, the coexistence of species within this radiation may not depend on the evolution of divergent resource use patterns.

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Ecological niche overlap among species of the genus Zaluzania (Asteraceae) from the dry regions of Mexico

Plant Ecology and Evolution ◽

10.5091/plecevo.2020.1633 ◽

2020 ◽

Vol 153 (3) ◽

pp. 337-347

Author(s):

Mario Ernesto Suárez-Mota ◽

José Luis Villaseñor

Keyword(s):

Ecological Niche ◽

Potential Distribution ◽

Area Under The Curve ◽

Niche Overlap ◽

Ecological Niches ◽

Niche Conservatism ◽

Distribution Models ◽

Closely Related Species ◽

Environmental Pressures ◽

Fundamental Niche

Background and aims – The hypothesis of ecological niche conservatism postulates that closely related species share ecologically similar environments; that is, they tend to maintain the characteristics of their fundamental niche over time. The objective of this study is to evaluate the similarity and equivalence of the ecological niches among species of the genus Zaluzania (Asteraceae), characteristic of the Mexican arid and semi-arid regions, to infer their potential niche conservatism. Methods – Based on critically reviewed herbarium occurrence data, potential distribution models for eight species of Zaluzania were generated using the Maxent algorithm. The overlap between potential distribution areas was then evaluated using equivalence and ecological niche parameters implemented in the ENMTools software; for this we quantified the degree of overlap and similarity between the niches using the equivalence (D) and similarity (I) parameters.Key results – The resulting models show that species display areas of high suitability along the Mexican dry regions, as well as overlapping heterogeneous values. All models showed high AUC (Area Under the Curve) values (> 0.8). The D and I values between each pair of species showed low values of overlap.Conclusions – Each species of the genus shows a fundamental niche distinct from their sister species. The genus thus offers an example of niche divergence among species, with each one adapting to different environmental pressures. Our results do not support the hypothesis of niche conservatism in the genus, suggesting that the species evolved in divergent environments.

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Could the intertidal Ellisolandia elongata reef be affected by climate changes expected in the near future in the Mediterranean Sea?

10.7287/peerj.preprints.1643 ◽

2016 ◽

Author(s):

Matteo Nannini ◽

Maurizio Florio ◽

Maria Chiara Manauzzi ◽

Agnese Marchini ◽

Giancarlo Raiteri ◽

...

Keyword(s):

Growth Rate ◽

Mediterranean Sea ◽

Climate Changes ◽

Industrial Revolution ◽

Effect Of Temperature ◽

Ecological Niches ◽

Associated Fauna ◽

Experimental Conditions ◽

The Mediterranean ◽

Near Future

The concentration of Green House Gasses and specifically the concentration of CO2 in the atmosphere is continuously increasing since the industrial revolution and it is the most relevant anthropic cause driving climate changes. Two of the strongest symptoms of those changes are the Global Warming and the Ocean Acidification which are progressively altering marine ecosystems and the populations of living organisms they support. The Mediterranean Sea is widely considered a 'laboratory basin' by suffering dramatic changes in its oceanographic and biogeochemical conditions derived from natural and anthropogenic forces. Calcifying seaweeds are the most important 'bioconstructors', from mesolittoral to circalittoral fringe, providing habitats and ecological niches for other species (i.e. biodiversity promoters) but also are good 'recorders' of the environmental condition they experience (i.e. biondicators). In this study we focused on the reef-forming Ellisolandia elongata from the Gulf of La Spezia (N-W Mediterranean Sea) by comparing the physical properties, growth rate and abundance of associated fauna in natural and experimental conditions (temperature and pH expected for 2050-2100). Four sampling sites were chosen in the intertidal zone. Reef samples were bring in the laboratory and put in experimental conditions for a month. Four aquaria simulated the actual conditions of temperature and pH, other 4 aquaria simulated temperature (+3°C) and pH (7.7) expected for the year near future. E. elongata grown in the natural and experimental conditions withstand mechanical stress in slightly different ways. The study of the effect of temperature and pH variations on growth rate and associated fauna of E. elongata reef is still in progress.

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Could the intertidal Ellisolandia elongata reef be affected by climate changes expected in the near future in the Mediterranean Sea?

10.7287/peerj.preprints.1643v1 ◽

2016 ◽

Author(s):

Matteo Nannini ◽

Maurizio Florio ◽

Maria Chiara Manauzzi ◽

Agnese Marchini ◽

Giancarlo Raiteri ◽

...

Keyword(s):

Growth Rate ◽

Mediterranean Sea ◽

Climate Changes ◽

Industrial Revolution ◽

Effect Of Temperature ◽

Ecological Niches ◽

Associated Fauna ◽

Experimental Conditions ◽

The Mediterranean ◽

Near Future

The concentration of Green House Gasses and specifically the concentration of CO2 in the atmosphere is continuously increasing since the industrial revolution and it is the most relevant anthropic cause driving climate changes. Two of the strongest symptoms of those changes are the Global Warming and the Ocean Acidification which are progressively altering marine ecosystems and the populations of living organisms they support. The Mediterranean Sea is widely considered a 'laboratory basin' by suffering dramatic changes in its oceanographic and biogeochemical conditions derived from natural and anthropogenic forces. Calcifying seaweeds are the most important 'bioconstructors', from mesolittoral to circalittoral fringe, providing habitats and ecological niches for other species (i.e. biodiversity promoters) but also are good 'recorders' of the environmental condition they experience (i.e. biondicators). In this study we focused on the reef-forming Ellisolandia elongata from the Gulf of La Spezia (N-W Mediterranean Sea) by comparing the physical properties, growth rate and abundance of associated fauna in natural and experimental conditions (temperature and pH expected for 2050-2100). Four sampling sites were chosen in the intertidal zone. Reef samples were bring in the laboratory and put in experimental conditions for a month. Four aquaria simulated the actual conditions of temperature and pH, other 4 aquaria simulated temperature (+3°C) and pH (7.7) expected for the year near future. E. elongata grown in the natural and experimental conditions withstand mechanical stress in slightly different ways. The study of the effect of temperature and pH variations on growth rate and associated fauna of E. elongata reef is still in progress.

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River dynamics and invasion: distribution patterns of native and invasive woody vegetation at the Río Negro, Argentina

Riparian Ecology and Conservation ◽

10.1515/remc-2015-0001 ◽

2015 ◽

Vol 2 (1) ◽

pp. 45-57 ◽

Cited By ~ 3

Author(s):

Lisa K. Thomas ◽

Eva Mosner ◽

Ilona Leyer

Keyword(s):

Niche Overlap ◽

Ecological Niches ◽

Life Stages ◽

Riparian Ecosystems ◽

Distribution Models ◽

Potential Threat ◽

Randomized Sampling ◽

Rio Negro ◽

Invasive Taxa ◽

The Impact

AbstractSalicaceae are typical invaders of riparian ecosystems throughout the world and they have the potential to change much of the invaded habitats. Along Patagonian streams, riparian softwood forests composed of non-native Salicaceae are increasing in abundance, area and tree species diversity. Especially in the last decades, dense floodplain forests dominated by invasive willows and poplars and additionally Russian olive and tamarisk spread almost explosively e.g. along the Río Negro in northern Patagonia. This study focuses on the identification of ecological niches and niche overlaps of the native and invasive woody species in order to assess the impact on the native Salix humboldtiana Willd. Data on species (presence/ absence) and explanatory variables were gathered in the field using a grid-based, stratified-randomized sampling design. Different environmental variables were then related to species occurrence in different life stages (adult, juvenile, seedling) using habitat distribution models. In the final models, flood duration, the amount of gravel and the location (upper or middle river valley) were included to describe the probability of occurrence of native and invasive taxa. For all life stages, a strong niche overlap could be observed for S. humboldtiana and the invasive taxa with no remaining exclusive habitats indicating a potential threat to the native willow. The study contributes to a better understanding of Salicaceae invasion and its consequences for riparian ecosystems.

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Alexandrium catenella and Alexandrium minutum blooms in the Mediterranean Sea: Toward the identification of ecological niches

Harmful Algae ◽

10.1016/j.hal.2007.11.005 ◽

2008 ◽

Vol 7 (4) ◽

pp. 515-522 ◽

Cited By ~ 48

Author(s):

Isabel Bravo ◽

Magda Vila ◽

Mercedes Masó ◽

Rosa Isabel Figueroa ◽

Isabel Ramilo

Keyword(s):

Mediterranean Sea ◽

Ecological Niches ◽

Alexandrium Minutum ◽

Alexandrium Catenella ◽

The Mediterranean

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Ecological niches of three teuthophageous odontocetes in the northwestern Mediterranean Sea

Ocean Science ◽

10.5194/os-4-49-2008 ◽

2008 ◽

Vol 4 (1) ◽

pp. 49-59 ◽

Cited By ~ 51

Author(s):

E. Praca ◽

A. Gannier

Keyword(s):

Mediterranean Sea ◽

Sperm Whale ◽

Ecological Niches ◽

Sperm Whales ◽

Ligurian Sea ◽

Data Set ◽

Pilot Whale ◽

Northwestern Mediterranean Sea ◽

Pilot Whales ◽

Northwestern Mediterranean

Abstract. In the northwestern Mediterranean Sea, sperm whales, pilot whales and Risso's dolphins prey exclusively or preferentially on cephalopods. In order to evaluate their competition, we modelled their habitat suitability with the Ecological Niche Factor Analysis (ENFA) and compared their ecological niches using a discriminant analysis. We used a long term (1995–2005) small boat data set, with visual and acoustic (sperm whale) detections. Risso's dolphin had the shallowest and the more spatially restricted principal habitat, mainly located on the upper part of the continental slope (640 m mean depth). With a wider principal habitat, at 1750 m depth in average, the sperm whale used a deeper part of the slope as well as the closest offshore waters. Finally, the pilot whale has the most oceanic habitat (2500 m mean depth) mainly located in the central Ligurian Sea and Provençal basin. Therefore, potential competition for food between these species may be reduced by the differentiation of their habitats.

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Impact of mating system on range size and niche breadth in Epipactis (Orchidaceae)

Annals of Botany ◽

10.1093/aob/mcaa142 ◽

2020 ◽

Vol 126 (7) ◽

pp. 1203-1214

Author(s):

Alexandra Evans ◽

Hans Jacquemyn

Keyword(s):

Mating System ◽

Plant Species ◽

Habitat Suitability ◽

Mating Systems ◽

Niche Breadth ◽

Plant Traits ◽

Niche Overlap ◽

Range Size ◽

Ecological Niches ◽

Evolutionary Potential

Abstract Background and Aims The geographical distribution of plant species is linked fundamentally not only to environmental variables, but also to key traits that affect the dispersal, establishment and evolutionary potential of a species. One of the key plant traits that can be expected to affect standing genetic variation, speed of adaptation and the capacity to colonize and establish in new habitats, and therefore niche breadth and range size, is the plant mating system. However, the precise role of the mating system in shaping range size and niche breadth of plant species remains unclear, and different studies have provided contrasting results. In this study, we tested the hypothesis that range size and niche breadth differed with mating system in the orchid genus Epipactis. Methods We modelled the ecological niches of 14 Epipactis species in Europe using occurrence records and environmental satellite data in Maxent. Niche breadth and niche overlap in both geographic and environmental space were calculated from the resulting habitat suitability maps using ENMTools, and geographic range was estimated using α-hull range definition. Habitat suitability, environmental variable contributions and niche metrics were compared among species with different mating systems. Key Results We did not detect significant differences in niche breadth, occurrence probability or geographical range between autogamous and allogamous Epipactis species, although autogamous species demonstrated notably low variation in niche parameters. We also found no significant differences in niche overlap between species with the same mating system or different mating systems. For all Epipactis species, occurrence was strongly associated with land cover, particularly broad-leafed and coniferous forests, and with limestone bedrock. Conclusions These results suggest that the mating system does not necessarily contribute to niche breadth and differentiation, and that other factors (e.g. mycorrhizal specificity) may be more important drivers of range size and niche breadth in Epipactis and orchids in general.

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Ecological Significance of Microdiversity: Identical 16S rRNA Gene Sequences Can Be Found in Bacteria with Highly Divergent Genomes and Ecophysiologies

Applied and Environmental Microbiology ◽

10.1128/aem.70.8.4831-4839.2004 ◽

2004 ◽

Vol 70 (8) ◽

pp. 4831-4839 ◽

Cited By ~ 212

Author(s):

Elke Jaspers ◽

Jörg Overmann

Keyword(s):

16S Rrna ◽

16S Rrna Gene ◽

Niche Overlap ◽

Most Probable Number ◽

Ecological Niches ◽

Rrna Gene ◽

Gene Sequences ◽

16S Rrna Gene Sequences ◽

Probable Number ◽

Internally Transcribed Spacer

ABSTRACT A combination of cultivation-based methods with a molecular biological approach was used to investigate whether planktonic bacteria with identical 16S rRNA gene sequences can represent distinct eco- and genotypes. A set of 11 strains of Brevundimonas alba were isolated from a bacterial freshwater community by conventional plating or by using a liquid most-probable-number (MPN) dilution series. These strains had identical 16S rRNA gene sequences and represented the dominant phylotype in the plateable fraction, as well as in the highest positive dilutions of the MPN series. However, internally transcribed spacer and enterobacterial repetitive intergenic consensus PCR fingerprinting analyses, as well as DNA-DNA hybridization analyses, revealed great genetic diversity among the 11 strains. Each strain utilized a specific combination of 59 carbon substrates, and the niche overlap indices were low, suggesting that each strain occupied a different ecological niche. In dialysis cultures incubated in situ, each strain had a different growth rate and cell yield. We thus demonstrated that the B. alba strains represent distinct populations with genetically determined adaptations and probably occupy different ecological niches. Our results have implications for assessment of the diversity and biogeography of bacteria and increase the perception of natural diversity beyond the level of 16S rRNA gene sequences.

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