scholarly journals Species coexistence and overlapping distributions in a metacommunity are compatible with niche differences and competition at a local scale

2020 ◽  
Author(s):  
Maxime Dubart ◽  
Patrice David ◽  
Frida Ben-Ami ◽  
Christoph R. Haag ◽  
V. Ilmari Pajunen ◽  
...  
Keyword(s):  
Species Coexistence ◽  
Scale Up ◽  
Niche Partitioning ◽  
Niche Differentiation ◽  
Apparent Paradox ◽  
Extinction Rates ◽  
Interspecific Differences ◽  
Baltic Coast ◽  
Species Specific

AbstractNiche partitioning is the most studied factor structuring communities of competing species. In fragmented landscapes, however, a paradox can exist: different taxa may competitively dominate different types of habitat patches, resulting in a form of spatial niche partitioning, yet differences in long-term distributions among species can appear surprisingly small. This paradox is illustrated by an emblematic metacommunity - that of Daphnia spp. in rockpools on the Finnish Baltic coast, where three species compete with each other, have distinct ecological preferences, yet largely overlap in long-term distributions. Here we examine how metacommunity models that explicitly estimate species-specific demographic parameters can solve the apparent paradox. Our research confirms previous studies that local extinction rates are influenced by environmental variables in a strong and species-specific way and are considerably increased by interspecific competition. Yet, our simulations show that this situation exists alongside interspecific differences in realized niches that are, overall, small, and identified three main explanations for this compatibility. Our results illustrate how state-space modelling can clarify complex metacommunity dynamics and explain why local competition and niche differentiation do not always scale up to the landscape level.

scholarly journals Temporal niche partitioning of Swiss black scavenger flies in relation to season and substrate age (Diptera, Sepsidae)

2019 ◽  
Vol 3 ◽  
pp. 1-10 ◽  
Author(s):  
Patrick T. Rohner ◽  
Jean-Paul Haenni ◽  
Athene Giesen ◽  
Juan Pablo Busso ◽  
Martin A. Schäfer ◽  
...  
Keyword(s):  
Related Species ◽  
Species Coexistence ◽  
Species Turnover ◽  
Niche Partitioning ◽  
Temporal Distribution ◽  
Niche Differentiation ◽  
Ecological Niches ◽  
Phylogenetic Distance ◽  
Closely Related Species ◽  
Temporal Niche

Understanding why and how multiple species manage to coexist represents a primary goal of ecological and evolutionary research. This is of particular relevance for communities that depend on resource rich ephemeral habitats that are prone to high intra- and interspecific competition. Black scavenger flies (Diptera: Sepsidae) are common and abundant acalyptrate flies associated with livestock dung decomposition in human-influenced agricultural grasslands worldwide. Several widespread sepsid species with apparently very similar ecological niches coexist in Europe, but despite their ecological role and their use in evolutionary ecological research, our understanding of their ecological niches and spatio-temporal distribution is still rudimentary. To gain a better understanding of their ecology, we here investigate niche partitioning at two temporal scales. First, we monitored the seasonal occurrence, often related to thermal preference, over multiple years and sites in Switzerland that differ in altitude. Secondly, we also investigate fine-scale temporal succession on dairy cow pastures. In accordance with their altitudinal and latitudinal distribution in Europe, some species were common over the entire season with a peak in summer, hence classified as warm-loving, whereas others were primarily present in spring or autumn. Phenological differences thus likely contribute to species coexistence throughout the season. However, the community also showed pronounced species turnover related to cow pat age. Some species colonize particularly fresh dung and are gradually replaced by others. Furthermore, the correlation between co-occurrence and phylogenetic distance of species revealed significant under-dispersion, indicating that more closely related species are frequently recovered at the same location. As a whole, our data suggests temporal niche differentiation of closely related species that likely facilitates the rather high species diversity on Swiss cattle pastures. The underlying mechanisms allowing close relatives to co-occur however require further scrutiny.

scholarly journals The City in the Tropics: Lizard Community Structure and Spatial Resource Use Along an Habitat Gradient of the Dahomey Gap (West Africa)

2021 ◽  
Author(s):  
Luca Luiselli ◽  
Daniele Dendi ◽  
Fabio Petrozzi ◽  
Gabriel Hoinsoudé Segniagbeto
Keyword(s):  
Community Structure ◽  
West Africa ◽  
Niche Partitioning ◽  
Habitat Types ◽  
Lizard Species ◽  
Natural Habitats ◽  
Interspecific Differences ◽  
Forest Sites ◽  
Habitat Gradient ◽  
Species Specific

Abstract Studies on habitat gradients are particularly interesting for the community ecology theory, but almost no investigation has been carried out on community structure of any vertebrate groups along gradients of habitat that were modified by humans in historical or prehistorical times, such as for instance the Dahomey Gap in West Africa. Here, we analyze the community structure of lizards in suburban Lomé (Togo) and in comparison with nearby savannah and forest sites, with a suite of statistical methods. Overall, we recorded 25 lizard species, with a heavy reduction in species richness from forest (18 taxa) to savannah (13) and suburbs (9). 24% of the species occurred in all habitat types, 40% exclusively in forest, and only two were exclusive of suburban habitats. Suburban habitat types were relatively homogeneous in terms of number of observed species (maximum number of taxa per habitat = 6). There were significant interspecific differences in both substratum type preferences and vertical spatial niche by species, but with no evidence of a nonrandom niche partitioning pattern, and hence with a competitively assembled community structure. There was a nonrandom “clustered” distribution of the various species along the available resource categories, thus indicating that species-specific preferences instead of community-driven mechanisms are more likely to explain the observed patterns. We concluded that lizard communities in tropical cities are (i) less species-rich than in the surrounding more natural habitats, (ii) usually clustered into specific habitat/substratum types (often artificial ones), and (iii) not assembled through competitive interactions.

Long-term in vitro Storage Technique of Valuable Birch Genotypes and Plant Production on its Basis

2019 ◽  
pp. 57-67
Author(s):  
T.M. Tabatskaya ◽  
N.I. Vnukova
Keyword(s):  
Plant Production ◽  
High Survival ◽  
Ex Vitro ◽  
Regenerative Capacity ◽  
In Vitro Storage ◽  
Interspecific Differences ◽  
Regenerated Plants ◽  
Growing Conditions

A technique for the long-term (up to 27 years) in vitro storage of valuable birch genotypes under normal (25 °C, 2.0 klx, 16-h day and 8-h night) and low temperature (4 °C, 0.5 klx, 6-h day and 18-h night) growing conditions on hormone-free media has been described. The study explored for the first time the influence of different strategies to store the clones of Betula pubescens and B. pendula var. сarelica (6 genotypes) on the regenerative capacity of collection samples, adaptive potential of regenerated plants and plant production by the in vitro and ex vitro techniques. It was established that both storage strategies provided a persistently high survival rate (82-100%) and regenerative capacity of in vitro shoots (the multiplication coefficient of 4.2-6.3 and rhizogenic activity of 90-100%). The clones retained their characteristics of height growth under the in vitro and ex vitro conditions, and demonstrated intraclonal homogeneity and lack of signs of somaclonal variability. The plants showed substantial interspecific differences at the stage of multiplication and transfer to the greenhouse. The highest percentage of acclimated plants (75-98% depending on the clone genotype) was obtained after planting of micro plants straight in the greenhouse, which simplified the technology and made plant production less costly. long-term in vitro storage, birch, species, genotype, micropropagation, ex vitro adaptation, plant material

From Start-Up to Scale-Up

2018 ◽  
Author(s):  
Gilles Duruflé ◽  
Thomas Hellmann ◽  
Karen Wilson
Keyword(s):  
United States ◽  
Conceptual Framework ◽  
Public Policies ◽  
Scale Up ◽  
The United States ◽  
Smart Money ◽  
Start Up ◽  
The Us ◽  
The Creation

This chapter examines the challenge for entrepreneurial companies of going beyond the start-up phase and growing into large successful companies. We examine the long-term financing of these so-called scale-up companies, focusing on the United States, Europe, and Canada. The chapter first provides a conceptual framework for understanding the challenges of financing scale-ups. It emphasizes the need for investors with deep pockets, for smart money, for investor networks, and for patient money. It then shows some data about the various aspects of financing scale-ups in the United States, Europe, and Canada, showing how Europe and Canada are lagging behind the US relatively more at the scale-up than the start-up stage. Finally, the chapter raises the question of long-term public policies for supporting the creation of a better scale-up environment.

scholarly journals Adopt, adapt, or abandon technology-supported person-centred care initiatives: healthcare providers’ beliefs matter

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Kari Dyb ◽  
Gro Rosvold Berntsen ◽  
Lisbeth Kvam
Keyword(s):  
Information Technologies ◽  
Scale Up ◽  
Healthcare Providers ◽  
Healthcare Services ◽  
Analytical Framework ◽  
Development Project ◽  
Technology Support ◽  
Care Needs ◽  
Term Care

Abstract Background Technology support and person-centred care are the new mantra for healthcare programmes in Western societies. While few argue with the overarching philosophy of person-centred care or the potential of information technologies, there is less agreement on how to make them a reality in everyday clinical practice. In this paper, we investigate how individual healthcare providers at four innovation arenas in Scandinavia experienced the implementation of technology-supported person-centred care for people with long-term care needs by using the new analytical framework nonadoption, abandonment, and challenges to the scale-up, spread, and sustainability (NASSS) of health and care technologies. We also discuss the usability and sensitivity of the NASSS framework for those seeking to plan, implement, and evaluate technology-supported healthcare programmes. This study is part of an interdisciplinary research and development project called Patients and Professionals in Partnership (2016–2020). It originates at one of ten work packages in this project. Method The main data consist of ethnographic field observations at the four innovation arenas and 29 interviews with involved healthcare providers. To ensure continuous updates and status on work in the four innovation arenas, we have also participated in a total of six annual network meetings arranged by the project. Results While the NASSS framework is very useful for identifying and communicating challenges with the adoption and spread of technology-supported person-centred care initiatives, we found it less sensitive towards capturing the dedication, enthusiasm, and passion for care transformation that we found among the healthcare providers in our study. When it comes to technology-supported person-centred care, the point of no return has passed for the involved healthcare providers. To them, it is already a definite part of the future of healthcare services. How to overcome barriers and obstacles is pragmatically approached. Conclusion Increased knowledge about healthcare providers and their visions as potential assets for care transformation might be critical for those seeking to plan, implement, and evaluate technology-supported healthcare programmes.

scholarly journals Bark traits, decomposition and flammability of Australian forest trees

2017 ◽  
Vol 65 (4) ◽  
pp. 327 ◽  
Author(s):  
Saskia Grootemaat ◽  
Ian J. Wright ◽  
Peter M. van Bodegom ◽  
Johannes H. C. Cornelissen ◽  
Veronica Shaw
Keyword(s):  
Forest Tree ◽  
Remarkable Feature ◽  
Interspecific Differences ◽  
Eucalypt Plantations ◽  
Physical Traits ◽  
Key Driver ◽  
Multiple Species ◽  
Species Specific ◽  
First Time ◽  
Different Tissues

Bark shedding is a remarkable feature of Australian trees, yet relatively little is known about interspecific differences in bark decomposability and flammability, or what chemical or physical traits drive variation in these properties. We measured the decomposition rate and flammability (ignitibility, sustainability and combustibility) of bark from 10 common forest tree species, and quantified correlations with potentially important traits. We compared our findings to those for leaf litter, asking whether the same traits drive flammability and decomposition in different tissues, and whether process rates are correlated across tissue types. Considerable variation in bark decomposability and flammability was found both within and across species. Bark decomposed more slowly than leaves, but in both tissues lignin concentration was a key driver. Bark took longer to ignite than leaves, and had longer mass-specific flame durations. Variation in flammability parameters was driven by different traits in the different tissues. Decomposability and flammability were each unrelated, when comparing between the different tissue types. For example, species with fast-decomposing leaves did not necessarily have fast-decomposing bark. For the first time, we show how patterns of variation in decomposability and flammability of bark diverge across multiple species. By taking species-specific bark traits into consideration there is potential to make better estimates of wildfire risks and carbon loss dynamics. This can lead to better informed management decisions for Australian forests, and eucalypt plantations, worldwide.

scholarly journals Foraging niche partitioning in sympatric seabird populations

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Christina Petalas ◽  
Thomas Lazarus ◽  
Raphael A. Lavoie ◽  
Kyle H. Elliott ◽  
Mélanie F. Guigueno
Keyword(s):  
Interspecific Competition ◽  
Niche Partitioning ◽  
Niche Differentiation ◽  
Sympatric Species ◽  
Foraging Strategies ◽  
Gps Tracking ◽  
Seabird Species ◽  
Foraging Range ◽  
Common Murre ◽  
Prey Items

AbstractSympatric species must sufficiently differentiate aspects of their ecological niche to alleviate complete interspecific competition and stably coexist within the same area. Seabirds provide a unique opportunity to understand patterns of niche segregation among coexisting species because they form large multi-species colonies of breeding aggregations with seemingly overlapping diets and foraging areas. Recent biologging tools have revealed that colonial seabirds can differentiate components of their foraging strategies. Specifically, small, diving birds with high wing-loading may have small foraging radii compared with larger or non-diving birds. In the Gulf of St-Lawrence in Canada, we investigated whether and how niche differentiation occurs in four incubating seabird species breeding sympatrically using GPS-tracking and direct field observations of prey items carried by adults to chicks: the Atlantic puffin (Fratercula arctica), razorbill (Alca torda), common murre (Uria aalge), and black-legged kittiwake (Rissa tridactyla). Although there was overlap at foraging hotspots, all species differentiated in either diet (prey species, size and number) or foraging range. Whereas puffins and razorbills consumed multiple smaller prey items that were readily available closer to the colony, murres selected larger more diverse prey that were accessible due to their deeper diving capability. Kittiwakes compensated for their surface foraging by having a large foraging range, including foraging largely at a specific distant hotspot. These foraging habitat specialisations may alleviate high interspecific competition allowing for their coexistence, providing insight on multispecies colonial living.

scholarly journals Niche partitioning by photosynthetic plankton as a driver of CO2-fixation across the oligotrophic South Pacific Subtropical Ocean

2021 ◽  
Author(s):  
Julia Duerschlag ◽  
Wiebke Mohr ◽  
Timothy G. Ferdelman ◽  
Julie LaRoche ◽  
Dhwani Desai ◽  
...  
Keyword(s):  
Mixed Layer ◽  
Niche Partitioning ◽  
Euphotic Zone ◽  
South Pacific ◽  
Niche Differentiation ◽  
Surface Mixed Layer ◽  
The South ◽  
The Core ◽  
Photosynthetic Eukaryotes ◽  
Phytoplankton Communities

AbstractOligotrophic ocean gyre ecosystems may be expanding due to rising global temperatures [1–5]. Models predicting carbon flow through these changing ecosystems require accurate descriptions of phytoplankton communities and their metabolic activities [6]. We therefore measured distributions and activities of cyanobacteria and small photosynthetic eukaryotes throughout the euphotic zone on a zonal transect through the South Pacific Ocean, focusing on the ultraoligotrophic waters of the South Pacific Gyre (SPG). Bulk rates of CO2 fixation were low (0.1 µmol C l−1 d−1) but pervasive throughout both the surface mixed-layer (upper 150 m), as well as the deep chlorophyll a maximum of the core SPG. Chloroplast 16S rRNA metabarcoding, and single-cell 13CO2 uptake experiments demonstrated niche differentiation among the small eukaryotes and picocyanobacteria. Prochlorococcus abundances, activity, and growth were more closely associated with the rims of the gyre. Small, fast-growing, photosynthetic eukaryotes, likely related to the Pelagophyceae, characterized the deep chlorophyll a maximum. In contrast, a slower growing population of photosynthetic eukaryotes, likely comprised of Dictyochophyceae and Chrysophyceae, dominated the mixed layer that contributed 65–88% of the areal CO2 fixation within the core SPG. Small photosynthetic eukaryotes may thus play an underappreciated role in CO2 fixation in the surface mixed-layer waters of ultraoligotrophic ecosystems.

scholarly journals Environmental correlates and energetics of winter flight by bats in southern Alberta, Canada

2016 ◽  
Vol 94 (12) ◽  
pp. 829-836 ◽  
Author(s):  
B.J. Klüg-Baerwald ◽  
L.E. Gower ◽  
C.L. Lausen ◽  
R.M. Brigham
Keyword(s):  
Heat Loss ◽  
Barometric Pressure ◽  
Myotis Lucifugus ◽  
Energetic Cost ◽  
Cold Temperatures ◽  
Bat Activity ◽  
Environmental Correlates ◽  
Interspecific Differences ◽  
Winter Activity ◽  
Species Specific

Winter activity of bats is common, yet poorly understood. Other studies suggest a relationship between winter activity and ambient temperature, particularly temperature at sunset. We recorded echolocation calls to determine correlates of hourly bat activity in Dinosaur Provincial Park, Alberta, Canada. We documented bat activity in temperatures as low as −10.4 °C. We observed big brown bats (Eptesicus fuscus (Palisot de Beauvois, 1796)) flying at colder temperatures than species of Myotis bats (genus Myotis Kaup, 1829). We show that temperature and wind are important predictors of winter activity by E. fuscus and Myotis, and that Myotis may also use changes in barometric pressure to cue activity. In the absence of foraging opportunity, we suggest these environmental factors relate to heat loss and thus the energetic cost of flight. To understand the energetic consequences of bat flight in cold temperatures, we estimated energy expenditure during winter flights of E. fuscus and little brown myotis (Myotis lucifugus (Le Conte, 1831)) using species-specific parameters. We estimated that winter flight uses considerable fat stores and that flight thermogenesis could mitigate energetic costs by 20% or more. We also show that temperature-dependent interspecific differences in winter activity likely stem from differences between species in heat loss and potential for activity–thermoregulatory heat substitution.

Temperature as a Proximate Factor in Orientation Behavior

1977 ◽  
Vol 34 (5) ◽  
pp. 734-739 ◽  
Author(s):  
William W. Reynolds
Keyword(s):  
Temperature Response ◽  
Biotic Interactions ◽  
Niche Differentiation ◽  
Behavioral Thermoregulation ◽  
Size Segregation ◽  
Ecological Value ◽  
Thermal Requirements ◽  
Prey Location ◽  
Proximate Factor ◽  
Species Specific

Temperature serves as a proximate factor (cue, guidepost, sign stimulus, or directive factor) affecting locomotor responses of fishes. Although temperature can also serve as an ultimate ecological factor, as in behavioral thermoregulation, nonthermal factors may in some cases provide the ultimate adaptive or ecological value of a temperature response; some examples are habitat selection, intraspecific size segregation, interspecific niche differentiation, isolating mechanisms, predator avoidance, prey location, escape reactions, and migrations (thermoperiodic, diel, seasonal, spawning). Conversely, nonthermal variables such as light intensity or water depth may act as accessory proximate factors in thermoregulation. In spawning migrations, thermal requirements of eggs and larvae may take precedence over the (often different) preferenda or optima of adults. Although thermal responses of fishes are largely innate and species specific, ontogenetic and other changes can occur. Since temperature can serve as an unconditioned reinforcer in operant conditioning, thermal responses are not limited to simple kineses or taxes. Nonthermal factors such as photoperiod, circadian rhythms, currents, social and biotic interactions, stresses, infections, or chemicals can affect thermal responses, and may account for some lack of conformity between laboratory preferenda and field distributions and behaviors. Key words: thermoregulation, orientation, preferendum, selection, preference, avoidance, behavior, temperature, fish, responses

Sign in / Sign up

Export Citation Format

Share Document