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Costa-Pereira R, Shaner PJL. The spatiotemporal context of individual specialization in resource use and environmental associations. J Anim Ecol 2024. [PMID: 38706400 DOI: 10.1111/1365-2656.14090] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2023] [Accepted: 03/14/2024] [Indexed: 05/07/2024]
Abstract
1. Individual niche specialization is widespread in natural populations and has key implications for higher levels of biological organization. This phenomenon, however, has been primarily quantified in resource niche axes, overlooking individual variation in environmental associations (i.e. abiotic conditions organisms experience). 2. Here, we explore what we can learn from a multidimensional perspective of individual niche specialization that integrates resource use and environmental associations into a common framework. 3. By combining predictions from theory and simple simulations, we illustrate how (i) multidimensional intraspecific niche variation and (ii) the spatiotemporal context of interactions between conspecifics scale up to shape emergent patterns of the population niche. 4. Contemplating individual specialization as a multidimensional, unifying concept across biotic and abiotic niche axes is a fundamental step towards bringing this concept closer to the n-dimensional niche envisioned by Hutchinson.
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Affiliation(s)
- Raul Costa-Pereira
- Department of Animal Biology, Institute of Biology, Universidade Estadual de Campinas (Unicamp), Campinas, Brazil
| | - Pei-Jen Lee Shaner
- Department of Life Science, National Taiwan Normal University, Taipei, Taiwan
- Department of Natural Resources and Environmental Studies, National Dong Hwa University, Hualien, Taiwan
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2
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Cianferoni F, Lunghi E. Inferring on Speleomantes Foraging Behavior from Gut Contents Examination. Animals (Basel) 2023; 13:2782. [PMID: 37685046 PMCID: PMC10486601 DOI: 10.3390/ani13172782] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2023] [Revised: 08/30/2023] [Accepted: 08/31/2023] [Indexed: 09/10/2023] Open
Abstract
We here provide the first comprehensive analysis and discussion on prey consumed by the European cave salamanders of the genus Speleomantes. Our study stems from the need to shed light on the still unknown foraging behavior adopted by Speleomantes cave salamanders. Starting from the published datasets on gut contents from all Speleomantes species (including hybrids), we here discuss additional information (i.e., species ecology, lower taxonomic level), which were systematically omitted from those data sets. We analyzed a data set consisting of 17,630 records from 49 categories of consumed prey recognized from gut contents of 2060 adults and juveniles Speleomantes. Flying prey accounted for more than 58% of the prey items, while elongated crawling prey accounted for no more than 16% of the diet within a single population. Among the total recognized prey items, only three can be surely ascribed to the group of strictly-cave species (i.e., troglobites), meaning that European cave salamanders mostly forage in surface environment, and therefore represent one of the major drivers of allochthonous organic matter in subterranean environments. Some of the consumed prey seemed to be aquatic, allowing us to hypothesize whether Speleomantes are able to catch prey from a shallow body water. Furthermore, European cave salamanders possess the ability to prey upon taxa characterized by particular anti-predator defenses, while morphological constraints seem to be the most important limit to prey consumption. For each specific case, we provide insights and propose hypotheses concerning the foraging behavior that need to be tested to properly understand the foraging behavior of this cryptic salamanders.
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Affiliation(s)
- Fabio Cianferoni
- Research Institute on Terrestrial Ecosystems (IRET), National Research Council of Italy (CNR), 50019 Firenze, Italy;
- Natural History Museum of the University of Florence, “La Specola”, 50125 Firenze, Italy
| | - Enrico Lunghi
- Department of Life Health and Environmental Sciences (MeSVA), Università degli Studi dell’Aquila, 67100 L’Aquila, Italy
- Associazione Natural Oasis, 59100 Prato, Italy
- Unione Speleologica Calenzano, 50041 Calenzano, Italy
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3
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Costa A, Rosa G, Salvidio S. Size-Mediated Trophic Interactions in Two Syntopic Forest Salamanders. Animals (Basel) 2023; 13:ani13081281. [PMID: 37106844 PMCID: PMC10135349 DOI: 10.3390/ani13081281] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2023] [Revised: 04/05/2023] [Accepted: 04/06/2023] [Indexed: 04/29/2023] Open
Abstract
Exploitative competition and interference competition differ in the way they affect re-source availability for competitors: in the former, organisms reduce resource availability for the competitors; in the latter, one organism actively prevents the competitor from accessing resources, independently of their availability. Our aim is to test for the presence of foraging competition in two forest-dwelling salamanders in Italy: Speleomantes strinatii and Salamandrina perspicillata. We also aim at testing for size-mediated competition. We obtained stomach contents from 191 sampled individuals by means of stomach flushing at 8 sampling sites where both species occur. We focused our analysis on the core prey taxa shared by both species: Collembola and Acarina. We found that the foraging activity of S. perspicillata is positively affected by body size and negatively affected by potential competitor's activity on the forest floor during the sampling, which also significantly weakened the positive relationship with body size. These results suggest the presence of an interference/interaction occurring between the two species and affecting the foraging activity of S. perspicillata. This competitive interaction is size mediated and configured as interference competition rather than exploitative competition.
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Affiliation(s)
- Andrea Costa
- Department of Earth, Environment and Life Sciences (DISTAV), University of Genova, Corso Europa 26, 16132 Genova, Italy
| | - Giacomo Rosa
- Department of Earth, Environment and Life Sciences (DISTAV), University of Genova, Corso Europa 26, 16132 Genova, Italy
| | - Sebastiano Salvidio
- Department of Earth, Environment and Life Sciences (DISTAV), University of Genova, Corso Europa 26, 16132 Genova, Italy
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4
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Cogoni R, Di Gregorio M, Cianferoni F, Lunghi E. Monitoring of the Endangered Cave Salamander Speleomantes sarrabusensis. Animals (Basel) 2023; 13:ani13030391. [PMID: 36766280 PMCID: PMC9913285 DOI: 10.3390/ani13030391] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2022] [Revised: 01/11/2023] [Accepted: 01/20/2023] [Indexed: 01/27/2023] Open
Abstract
In this study, we performed the first monitoring activities on one of the most endangered amphibians in Europe, the Sette Fratelli cave salamander Speleomantes sarrabusensis. The data presented here are derived from two monitoring activities aiming to assess the status and abundance of four populations of S. sarrabusensis. With the first monitoring, we surveyed the well-known population occurring within artificial springs during the period 2015-2018, providing monthly data on the number of active individuals. With the second monitoring performed during spring to early summer of 2022, we surveyed four populations at three time points (the one from artificial springs and three from forested areas) and we provided the first estimation of the populations' abundance. Furthermore, we analyzed for the first time the stomach contents from a population of S. sarrabusensis only occurring in forested environments. With our study, we provided the first information on the abundance of different populations of S. sarrabusensis, representing the starting point for future status assessments for this endangered species.
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Affiliation(s)
- Roberto Cogoni
- Unione Speleologica Cagliaritana, Quartu Sant’Elena, 09045 Cagliari, Italy
| | - Milos Di Gregorio
- Dipartimento di Biologia, Università degli Studi di Pisa, 56126 Pisa, Italy
- Correspondence:
| | - Fabio Cianferoni
- Istituto di Ricerca sugli Ecosistemi Terrestri (IRET), Consiglio Nazionale delle Ricerche (CNR), Sesto Fiorentino, 50019 Firenze, Italy
- Museo di Storia Naturale dell’Università degli Studi di Firenze, “La Specola”, 50125 Firenze, Italy
| | - Enrico Lunghi
- Dipartimento di Medicina Clinica, Sanità Pubblica, Scienze Della Vita e dell’ambiente (MeSVA), Universià degli Studi dell’Aquila, 67100 L’Aquila, Italy
- Associazione Natural Oasis, 59100 Prato, Italy
- Unione Speleologica Calenzano, 50041 Calenzano, Italy
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5
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Lunghi E, Cianferoni F, Corti C, Zhao Y, Manenti R, Ficetola GF, Mancinelli G. The trophic niche of subterranean populations of Speleomantes italicus. Sci Rep 2022; 12:18257. [PMID: 36309527 PMCID: PMC9617932 DOI: 10.1038/s41598-022-21819-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2022] [Accepted: 10/04/2022] [Indexed: 12/31/2022] Open
Abstract
The determination of a species trophic niche can clarify its functional role within a food web and how prey resources are used in relation with the spatial and temporal variability of environmental conditions. This information may result particularly useful for the implementation of conservation plans of endangered species having a cryptic behaviour or living in places difficult to be surveyed. Here we present the first long-term study on the trophic niche of the Italian cave salamander Speleomantes italicus, a strictly protected facultative cave species that seasonally exploits surface environments (e.g., forested areas) as well as both natural and artificial subterranean environments. We analysed the diet variation of six populations of S. italicus inhabiting natural caves, surveyed 24 times in a full year. During the surveys, all sampled individuals were subjected to stomach flushing and the ingested prey were identified and enumerated; furthermore, salamanders' body condition was also evaluated. The results of the analyses provided the first comprehensive, year-round assessment of the diet for a Speleomantes species. Remarkable divergences in terms of trophic niche and body condition were observed between the studied populations. We found a discrepancy in the foraging activity of the populations located in different areas; specifically, the individuals that experienced sub-optimal microclimatic conditions poorly performed in foraging. Furthermore, we found temporal and spatial variability in the body condition of individuals. Our study highlighted a remarkably high spatial and temporal divergence in the trophic habits of conspecific populations, a feature that may represent one of the major factors promoting the variability of multiple population traits.
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Affiliation(s)
- Enrico Lunghi
- grid.9227.e0000000119573309Key Laboratory of the Zoological Systematics and Evolution, Institute of Zoology, Chinese Academy of Sciences, Beijing, China ,grid.158820.60000 0004 1757 2611Dipartimento di Medicina clinica, sanità pubblica, scienze della vita e dell’ambiente (MESVA), University of L’Aquila, Coppito, L’Aquila Italy ,grid.8404.80000 0004 1757 2304Zoologia, “La Specola”, Museo di Storia Naurale, Università degli Studi di Firenze, Florence, Italy ,Natural Oasis, Prato, Italy ,Unione Speleologica Calenzano, Calenzano, Florence, Italy
| | - Fabio Cianferoni
- grid.8404.80000 0004 1757 2304Zoologia, “La Specola”, Museo di Storia Naurale, Università degli Studi di Firenze, Florence, Italy ,grid.5326.20000 0001 1940 4177Istituto di Ricerca Sugli Ecosistemi Terrestri (IRET), Consiglio Nazionale delle Ricerche (CNR), Sesto Fiorentino, Florence Italy
| | - Claudia Corti
- grid.8404.80000 0004 1757 2304Zoologia, “La Specola”, Museo di Storia Naurale, Università degli Studi di Firenze, Florence, Italy
| | - Yahui Zhao
- grid.9227.e0000000119573309Key Laboratory of the Zoological Systematics and Evolution, Institute of Zoology, Chinese Academy of Sciences, Beijing, China
| | - Raoul Manenti
- grid.4708.b0000 0004 1757 2822Dipartimento di Scienze e Politiche Ambientali, Università degli Studi di Milano, Milano, Italy ,Laboratorio di Biologia Sotterranea “Enrico Pezzoli”, Parco Regionale del Monte Barro, Galbiate, Italy
| | - Gentile Francesco Ficetola
- grid.4708.b0000 0004 1757 2822Dipartimento di Scienze e Politiche Ambientali, Università degli Studi di Milano, Milano, Italy ,grid.450308.a0000 0004 0369 268XLaboratoire d’Écologie Alpine (LECA), Université Grenoble Alpes, CNRS, Grenoble, France
| | - Giorgio Mancinelli
- grid.9906.60000 0001 2289 7785Dipartimento di Scienze e Tecnologie Biologiche ed Ambientali (DiSTeBA), Università del Salento, Lecce, Italy ,grid.5326.20000 0001 1940 4177Istituto per le Risorse Biologiche e le Biotecnologie Marine (IRBIM), Consiglio Nazionale delle Ricerche (CNR), Lesina, Foggia Italy ,grid.10911.380000 0005 0387 0033CoNISMa, Consorzio Nazionale Interuniversitario per le Scienze del Mare, Roma, Italy
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The Trophic Niche of Two Sympatric Species of Salamanders (Plethodontidae and Salamandridae) from Italy. Animals (Basel) 2022; 12:ani12172221. [PMID: 36077941 PMCID: PMC9454711 DOI: 10.3390/ani12172221] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2022] [Revised: 08/12/2022] [Accepted: 08/21/2022] [Indexed: 11/30/2022] Open
Abstract
Simple Summary Studies on species’ trophic niches are essential to understand the characteristics of species’ ecology and life traits, as well as to improve conservation strategies. In the absence of competitors, species realize their trophic niche including in their diet the most profitable food resources. In the presence of competitors, species modify their preferences to reduce competition and maintain the highest benefits at the same time. In this study, we assessed the trophic niche of two species of salamanders coexisting in a forested area of Italy and evaluated which might be the mechanisms that these two species adopted to reduce competition. We found that the Italian cave salamander (Speleomantes italicus) mostly consumed flying prey with a hard cuticle, while the fire salamander (Salamandra salamandra) preferred worm-like and soft-bodied prey. In conclusion, we hypothesize that in our case, the two species of salamanders did not have to change their prey preference in order to avoid competition, but divergences in metabolism and behavioral traits likely worked as natural deterrent. Abstract The trophic niche of a species is one of the fundamental traits of species biology. The ideal trophic niche of a species is realized in the absence of interspecific competition, targeting the most profitable and easy-to-handle food resources. However, when a competitor is present, species adopt different strategies to reduce competition and promote coexistence. In this study, we assessed the potential mechanisms that allow the coexistence of two generalist salamanders: the Italian cave salamander (Speleomantes italicus) and the fire salamander (Salamandra salamandra). We surveyed, in April 2021, a forested area of Emilia-Romagna (Italy) during rainy nights. Analyzing the stomach contents of the captured individuals, we obtained information on the trophic niche of these two sympatric populations. Comparing our results with those of previous studies, we found that the two species did not modify their trophic niche, but that alternative mechanisms allowed their coexistence. Specifically, different prey preferences and predator metabolisms were likely the major factors allowing reduced competition between these two generalist predators.
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7
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Aziz MA, Mattalia G, Sulaiman N, Shah AA, Polesny Z, Kalle R, Sõukand R, Pieroni A. The nexus between traditional foraging and its sustainability: a qualitative assessment among a few selected Eurasian case studies. ENVIRONMENT, DEVELOPMENT AND SUSTAINABILITY 2022:1-26. [PMID: 35915718 PMCID: PMC9330945 DOI: 10.1007/s10668-022-02568-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/06/2022] [Accepted: 07/08/2022] [Indexed: 06/15/2023]
Abstract
Plant foraging is an important human ecological phenomenon being studied by a number of contemporary ethnobiologists as well as by a few social anthropologists among rural communities and, more recently, in urban environments. The sustainability dimension of foraging is, however, largely unexplored. We analyse a few case studies from recent field research and qualitatively assess both the environmental and social sustainability of diverse patterns of traditional foraging practices in three distinct human ecological environments (horticulturalism-, forestry-, and pastoralism-driven) located in the Eastern Mediterranean, Eastern Europe, and North Pakistan, i.e. we address the question of when does traditional foraging become unsustainable and what factors may influence this. The main findings are multidimensional. First, in all case studies, we sometimes observed competitive foraging among the gatherers of certain wild food plants potentially causing ecological degradation; such unsustainable practices seem to be linked to the market pressure on certain species. However, also customs and norms promoted by states can be detrimental (former Soviet Union), as well as climate change (Eastern Europe), and marginalisation of some minority groups (Pakistan). Second, in the Mediterranean Syrian context, wild food plant resources are largely represented by widely available weedy "wild" vegetables, normally (but not exclusively) collected by women, and usually easily accessible; only very few wild food plants seem to be threatened due to specific market demands or to disequilibria created by household economic instabilities due to the recent war. We also argue that unsustainable foraging is enhanced by the abandonment of daily practices and continuous interaction with the natural environment and by the increasingly uneven distribution of active practical knowledge on wild food plants among the middle-aged and younger population. Facilitating the transmission of sustainable foraging knowledge and practices could be therefore crucial, also for coping with food insecurity in times of crisis; but for that to occur, holistic environmental and food educational frameworks, appropriate policies for fostering community-based biodiversity conservation and also social cohesion and communal management of lands should be seriously considered as well. Moreover, future gastronomic and eco-tourism initiatives, if organised in a thoughtful manner, could represent a positive turning point not only for the local small-scale economies of the considered rural communities but also for helping them to dynamically preserve the entire socio-ecological system underpinned in plant foraging and ultimately to better adapt to the current global crisis.
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Affiliation(s)
- Muhammad Abdul Aziz
- Department of Environmental Sciences, Informatics and Statistics, Ca’ Foscari University of Venice, Via Torino 155, 30172 Venice, Italy
| | - Giulia Mattalia
- Department of Environmental Sciences, Informatics and Statistics, Ca’ Foscari University of Venice, Via Torino 155, 30172 Venice, Italy
| | - Naji Sulaiman
- Department of Crop Sciences and Agroforestry, Faculty of Tropical AgriSciences, Czech University of Life Sciences Prague, Kamýcká 129, 165 00 Praha-Suchdol, Czech Republic
| | - Adnan Ali Shah
- Phytoecology Lab, Department of Botany, University of Peshawar, Peshawar, 25120 Pakistan
| | - Zbynek Polesny
- Department of Crop Sciences and Agroforestry, Faculty of Tropical AgriSciences, Czech University of Life Sciences Prague, Kamýcká 129, 165 00 Praha-Suchdol, Czech Republic
| | - Raivo Kalle
- University of Gastronomic Sciences, Piazza Vittorio Emanuele II 9, Pollenzo, 12042 Bra, Italy
| | - Renata Sõukand
- Department of Environmental Sciences, Informatics and Statistics, Ca’ Foscari University of Venice, Via Torino 155, 30172 Venice, Italy
| | - Andrea Pieroni
- University of Gastronomic Sciences, Piazza Vittorio Emanuele II 9, Pollenzo, 12042 Bra, Italy
- Department of Medical Analysis, Tishk International University, Erbil, Kurdistan 4401 Iraq
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8
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Lunghi E. Doubling the lifespan of European plethodontid salamanders. Ecology 2021; 103:e03581. [PMID: 34767644 DOI: 10.1002/ecy.3581] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/19/2021] [Revised: 08/30/2021] [Accepted: 09/22/2021] [Indexed: 11/11/2022]
Affiliation(s)
- Enrico Lunghi
- Division of Molecular Biology, Ruđer Bošković Institute, Bijenička cesta, 54, Zagreb, Croatia, 10000, Croatia.,Museo di Storia Naturale dell'Università degli Studi di Firenze "La Specola", via Romana, 17, Firenze, 50125, Italy.,Natural Oasis, via di Galceti, 141, Prato, 59100, Italy.,Unione Speleologica Calenzano, Piazza della stazione,1, Calenzano, 50041, Italy
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9
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Ecological Observations on Hybrid Populations of European Plethodontid Salamanders, Genus Speleomantes. DIVERSITY 2021. [DOI: 10.3390/d13070285] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Speleomantes are the only plethodontid salamanders present in Europe. Multiple studies have been performed to investigate the trophic niche of the eight Speleomantes species, but none of these studies included hybrid populations. For the first time, we studied the trophic niche of five Speleomantes hybrid populations. Each population was surveyed twice in 2020, and stomach flushing was performed on each captured salamander; stomach flushing is a harmless technique that allows stomach contents to be inspected. We also assessed the potential divergence in size and body condition between natural and introduced hybrids, and their parental species. Previously collected data on Speleomantes were included to increase the robustness of these analyses. In only 33 out of 134 sampled hybrid Speleomantes we recognized 81 items belonging to 11 prey categories. The frequency of empty stomachs was higher in females and individuals from natural hybrid populations, whereas the largest number of prey was consumed by males. We compared the total length and body condition of 685 adult salamanders belonging to three types of hybrids and three parental (sub)species. Three group of salamanders (one hybrid and two parental species) showed significantly larger size, whereas no difference in body condition was observed. This study provided novel ecological information on Speleomantes hybrid populations. We also provided insights into the potential divergence between hybrids and parental species in terms of size and body condition. We discuss our findings, and formulate several hypotheses that should be tested in the future.
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Updating salamander datasets with phenotypic and stomach content information for two mainland Speleomantes. Sci Data 2021; 8:150. [PMID: 34108483 PMCID: PMC8190193 DOI: 10.1038/s41597-021-00931-w] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2021] [Accepted: 04/27/2021] [Indexed: 11/26/2022] Open
Abstract
European plethodontid salamanders (genus Speleomantes; formerly Hydromantes) are a group of eight strictly protected amphibian species which are sensitive to human-induced environmental changes. Long-term monitoring is highly recommended to evaluate their status and to assess potential threats. Here we used two low-impact methodologies to build up a large dataset on two mainland Speleomantes species (S. strinatii and S. ambrosii), which represents an update to two previously published datasets, but also includes several new populations. Specifically, we provide a set of 851 high quality images and a table gathering stomach contents recognized from 560 salamanders. This dataset offers the opportunity to analyse phenotypic traits and stomach contents of eight populations belonging to two Speleomantes species. Furthermore, the data collection performed over different periods allows to expand the potential analyses through a wide temporal scale, allowing long-term studies. Measurement(s) | Gastric Content • Image | Technology Type(s) | light microscopy • Digital Photography | Sample Characteristic - Organism | Speleomantes • Hydromantes | Sample Characteristic - Environment | Subterranean • karst cave • mine | Sample Characteristic - Location | Italy • Region of Liguria • Municipality of Genova • Province of La Spezia |
Machine-accessible metadata file describing the reported data: 10.6084/m9.figshare.14346176
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11
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Mammola S, Lunghi E, Bilandžija H, Cardoso P, Grimm V, Schmidt SI, Hesselberg T, Martínez A. Collecting eco-evolutionary data in the dark: Impediments to subterranean research and how to overcome them. Ecol Evol 2021; 11:5911-5926. [PMID: 34141192 PMCID: PMC8207145 DOI: 10.1002/ece3.7556] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2021] [Revised: 03/23/2021] [Accepted: 03/25/2021] [Indexed: 12/25/2022] Open
Abstract
Caves and other subterranean habitats fulfill the requirements of experimental model systems to address general questions in ecology and evolution. Yet, the harsh working conditions of these environments and the uniqueness of the subterranean organisms have challenged most attempts to pursuit standardized research.Two main obstacles have synergistically hampered previous attempts. First, there is a habitat impediment related to the objective difficulties of exploring subterranean habitats and our inability to access the network of fissures that represents the elective habitat for the so-called "cave species." Second, there is a biological impediment illustrated by the rarity of most subterranean species and their low physiological tolerance, often limiting sample size and complicating laboratory experiments.We explore the advantages and disadvantages of four general experimental setups (in situ, quasi in situ, ex situ, and in silico) in the light of habitat and biological impediments. We also discuss the potential of indirect approaches to research. Furthermore, using bibliometric data, we provide a quantitative overview of the model organisms that scientists have exploited in the study of subterranean life.Our over-arching goal is to promote caves as model systems where one can perform standardized scientific research. This is important not only to achieve an in-depth understanding of the functioning of subterranean ecosystems but also to fully exploit their long-discussed potential in addressing general scientific questions with implications beyond the boundaries of this discipline.
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Affiliation(s)
- Stefano Mammola
- Laboratory for Integrative Biodiversity Research (LIBRe)Finnish Museum of Natural History (LUOMUS)University of HelsinkiHelsinkiFinland
- Dark‐MEG: Molecular Ecology GroupWater Research Institute (IRSA)National Research Council (CNR)VerbaniaItaly
| | - Enrico Lunghi
- Key Laboratory of the Zoological Systematics and EvolutionInstitute of ZoologyChinese Academy of SciencesBeijingChina
- Museo di Storia Naturale dell'Università degli Studi di Firenze“La Specola”FirenzeItaly
| | - Helena Bilandžija
- Department of Molecular BiologyRudjer Boskovic InstituteZagrebCroatia
| | - Pedro Cardoso
- Laboratory for Integrative Biodiversity Research (LIBRe)Finnish Museum of Natural History (LUOMUS)University of HelsinkiHelsinkiFinland
| | - Volker Grimm
- Department of Ecological ModellingHelmholtz Centre for Environmental Research – UFZLeipzigGermany
- Plant Ecology and Nature ConservationUniversity of PotsdamPotsdamGermany
- German Centre for Integrative Biodiversity Research (iDiv) Halle‐Jena‐LeipzigLeipzigGermany
| | - Susanne I. Schmidt
- Institute of HydrobiologyBiology Centre CASČeské BudějoviceCzech Republic
| | | | - Alejandro Martínez
- Dark‐MEG: Molecular Ecology GroupWater Research Institute (IRSA)National Research Council (CNR)VerbaniaItaly
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12
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Steube TR, Altenritter ME, Walther BD. Distributive stress: individually variable responses to hypoxia expand trophic niches in fish. Ecology 2021; 102:e03356. [PMID: 33811651 PMCID: PMC8244237 DOI: 10.1002/ecy.3356] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/10/2020] [Revised: 01/05/2021] [Accepted: 02/05/2021] [Indexed: 01/18/2023]
Abstract
Environmental stress can reshape trophic interactions by excluding predators or rendering prey vulnerable, depending on the relative sensitivity of species to the stressor. Classical models of food web responses to stress predict either complete predator exclusion from stressed areas or complete prey vulnerability if predators are stress tolerant. However, if the consumer response to the stress is individually variable, the result may be a distributive stress model (DSM) whereby predators distribute consumption pressure across a range of prey guilds and their trophic niche is expanded. We test these models in one of the largest hypoxic “Dead Zones” in the world, the northern Gulf of Mexico, by combining geochemical tracers of hypoxia exposure and isotope ratios to assess individual‐level trophic responses. Hypoxia‐exposed fish occupied niche widths that were 14.8% and 400% larger than their normoxic counterparts in two different years, consistent with variable displacement from benthic to pelagic food webs. The degree of isotopic displacement depended on the magnitude of hypoxia exposure. These results are consistent with the DSM and highlight the need to account for individually variable sublethal effects when predicting community responses to environmental stress.
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Affiliation(s)
- Tyler R Steube
- Department of Life Sciences, Texas A&M University-Corpus Christi, 6300 Ocean Drive, Corpus Christi, Texas, 78412, USA
| | - Matthew E Altenritter
- Department of Life Sciences, Texas A&M University-Corpus Christi, 6300 Ocean Drive, Corpus Christi, Texas, 78412, USA.,Department of Environmental Science & Ecology, The College at Brockport, State University of New York, 350 New Campus Drive, Brockport, New York, 14420, USA
| | - Benjamin D Walther
- Department of Life Sciences, Texas A&M University-Corpus Christi, 6300 Ocean Drive, Corpus Christi, Texas, 78412, USA
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Costa A, Romano A, Rosa G, Salvidio S. Weighted individual-resource networks in prey-predator systems: the role of prey availability on the emergence of modular structures. Integr Zool 2021; 17:115-127. [PMID: 33415838 DOI: 10.1111/1749-4877.12520] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Ecological networks, usually depicting interactions among species, have been recently down-scaled to the individual level, permitting description of patterns of inter-individual resource variation that are usually hindered at the species level. Optimal diet theory (ODT) models, applied to prey-predator systems, predict different patterns of nestedness and modularity in the network, depending on the available resources and intra-specific competition. The effect of resource availability on the emergence of networks structures, and ODT framework, has not yet fully been clarified. Here, we analyzed the structural patterns of individual-resource networks in 3 species of Mediterranean salamanders, in relation to changes in prey availability. We used weighted individual-resource network metrics to interpret the observed patterns, according to 3 ODT models. We found significant nestedness recurring in our study system, indicating that both selective and opportunistic individuals occur in the same population. Prey diversity, rather than abundance, was apparently related to inter-individual resource variation and promoted the emergence of significant modularity within all networks. The observed patterns of nestedness and modularity, together with the variation in resource diversity and intra-specific competition, are in agreement with the distinct preferences model of ODT. These findings suggest that in the focal prey-predator systems, individuals were able to perceive changes in prey diversity and to exploit in different ways the variations in composition of available resources, shifting their diet assembly rules accordingly. Our findings also confirm that the use of weighted individual-resource networks, in prey-predator systems, allows to disclose dynamics that are masked at the species or population level.
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Affiliation(s)
- Andrea Costa
- Department of Earth, Environment and Life Sciences (DISTAV), University of Genova, Genova, Italy
| | - Antonio Romano
- Italian National Research Council (CNR), Agriculture and Food Sciences Department (IBE), Institute of Bioeconomy - Biology, Roma, RM, Italy
| | - Giacomo Rosa
- Department of Earth, Environment and Life Sciences (DISTAV), University of Genova, Genova, Italy
| | - Sebastiano Salvidio
- Department of Earth, Environment and Life Sciences (DISTAV), University of Genova, Genova, Italy
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Same Diet, Different Strategies: Variability of Individual Feeding Habits across Three Populations of Ambrosi’s Cave Salamander (Hydromantes ambrosii). DIVERSITY 2020. [DOI: 10.3390/d12050180] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
European cave salamanders of the genus Hydromantes are a group of eight species endemic to Italy and south-eastern France. Knowledge on the trophic niche of European Hydromantes is poor, and the few available studies only partially investigate their feeding habits. We performed an in-depth study on the trophic niche of the Ambrosi’s cave salamander (H. ambrosii), assessing the potential divergences among three different populations. All the populations had a similar diet composition, showing a wider trophic niche in fall compared to spring. In only one population, “true specialists” were present; however, in all three populations, generalist individuals always represented the larger proportion. Interspecific and intraspecific competition did not play an important role in determining individual dietary specialisation in H. ambrosii; contrarily, the characteristics of the surrounding environment seemed to be an important factor. The best body conditions were observed in the population located in the site where the non-arboreal vegetation cover was the highest. Besides providing new information on the trophic niche of H. ambrosii, we here showed that studies encompassing both intrinsic and extrinsic factors at the population level are needed to fully understand the trophic dynamics occurring among European cave salamanders.
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