Pub Date : 2024-12-01DOI: 10.1016/j.fooweb.2024.e00381
Vinicius A. Robert , José L.S. Mello , Erika M. Shimabukuro , Victor S. Saito
Community size structure potentially depicts the constant amount of small abundant organisms sustaining larger, rarer ones. Strong size structuring is expected under a constant predator-prey mass ratio yet omnivory, as defined by organisms feeding at multiple trophic levels, can disrupt this pattern. Here, we investigated the size structure of macroinvertebrate communities in two tropical streams before and after a heavy rain event. We found that one taxon, Leptonema (a net-spinning caddisfly), was overabundant at all sites, strongly deviating from the allometric expectation given their body size. By analyzing their gut-content, we found evidence of true omnivory with inclusion of animal prey with increasing body size. As omnivory is a key factor in ecosystem stability, the presence of overabundant species could be an important element to consider when implementing conservation and restoration policies.
{"title":"Can omnivory explain variation in size-density relationships? The case of Leptonema in a neotropical stream","authors":"Vinicius A. Robert , José L.S. Mello , Erika M. Shimabukuro , Victor S. Saito","doi":"10.1016/j.fooweb.2024.e00381","DOIUrl":"10.1016/j.fooweb.2024.e00381","url":null,"abstract":"<div><div>Community size structure potentially depicts the constant amount of small abundant organisms sustaining larger, rarer ones. Strong size structuring is expected under a constant predator-prey mass ratio yet omnivory, as defined by organisms feeding at multiple trophic levels, can disrupt this pattern. Here, we investigated the size structure of macroinvertebrate communities in two tropical streams before and after a heavy rain event. We found that one taxon, <em>Leptonema</em> (a net-spinning caddisfly), was overabundant at all sites, strongly deviating from the allometric expectation given their body size. By analyzing their gut-content, we found evidence of true omnivory with inclusion of animal prey with increasing body size. As omnivory is a key factor in ecosystem stability, the presence of overabundant species could be an important element to consider when implementing conservation and restoration policies.</div></div>","PeriodicalId":38084,"journal":{"name":"Food Webs","volume":"41 ","pages":"Article e00381"},"PeriodicalIF":1.8,"publicationDate":"2024-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142747784","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-11-19DOI: 10.1016/j.fooweb.2024.e00380
Augusto N. Carvalho , Bruno L. de S. Bambirra , Leonardo B. Passalacqua , Filipe C. Serrano
Reporting predation events is crucial to understand how species behaviour and predator-prey interactions shape food webs. However, data is still lacking for most neotropical fauna, especially reptiles. Salvator merianae is a widespread lizard species, which is often found in human-altered habitats and has been introduced in multiple locations. This Neotropical lizard is omnivorous and acts as a necrophagous, seed disperser and predator of small-sized animals. However, in spite of extensive data on its generalist diet, detailed predation records over medium-sized vertebrates (between 1 and 40 kg) are scarce. Here we report the first records of S. merianae predation on three distinct armadillo species, all of which occurred in human-altered habitats in Brazil and Argentina. Our records contribute to a better understanding of trophic interactions in modified landscapes and how large reptiles, such as S. merianae, may play an important role in food webs in the absence of larger predators.
{"title":"Not armoured enough: The black-and-white tegu Salvator merianae (Squamata: Teiidae) as a predator of armadillos (Cingulata)","authors":"Augusto N. Carvalho , Bruno L. de S. Bambirra , Leonardo B. Passalacqua , Filipe C. Serrano","doi":"10.1016/j.fooweb.2024.e00380","DOIUrl":"10.1016/j.fooweb.2024.e00380","url":null,"abstract":"<div><div>Reporting predation events is crucial to understand how species behaviour and predator-prey interactions shape food webs. However, data is still lacking for most neotropical fauna, especially reptiles. <em>Salvator merianae</em> is a widespread lizard species, which is often found in human-altered habitats and has been introduced in multiple locations. This Neotropical lizard is omnivorous and acts as a necrophagous, seed disperser and predator of small-sized animals. However, in spite of extensive data on its generalist diet, detailed predation records over medium-sized vertebrates (between 1 and 40 kg) are scarce. Here we report the first records of <em>S. merianae</em> predation on three distinct armadillo species, all of which occurred in human-altered habitats in Brazil and Argentina. Our records contribute to a better understanding of trophic interactions in modified landscapes and how large reptiles, such as <em>S. merianae,</em> may play an important role in food webs in the absence of larger predators.</div></div>","PeriodicalId":38084,"journal":{"name":"Food Webs","volume":"41 ","pages":"Article e00380"},"PeriodicalIF":1.8,"publicationDate":"2024-11-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142698520","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-11-17DOI: 10.1016/j.fooweb.2024.e00379
Paula Kankaala , Kimmo K. Kahilainen , Mikko Olin , Antti J. Rissanen
The size of a lake ecosystem sets many direct and indirect physical limits for habitats available for different food web compartments as well as the taxa inhabiting these. We tested the hypotheses that 1) reliance of fish on littoral resources increase in lakes with shoreline development, and 2) food chain length and 3) top predator size increase with lake size. We analyzed food web trophic structure, based on stable isotope analyses (SIA) of carbon (δ13C) and nitrogen (δ15N), in six boreal lakes in southern and eastern Finland (area 0.13–567 km2). We also applied data from gillnet monitoring of two common predatory fish, perch (Perca fluviatilis) and pike (Esox lucius), in >100 lakes as well as data from national large pike (weight > 10 kg) competition. Our results based on SIA did not support the first two hypotheses. Mixing-model results indicated great contribution of littoral resources for many fish, however, showing considerable within-taxa variation for some species. Fish reliance on littoral resources was not directly related to lake shoreline development. The lakes had four trophic levels and large predators coupled both littoral and pelagic habitats. The very rare freshwater pinniped, Saimaa ringed seal (Pusa hispida saimensis), shared the same trophic position with piscivorous fish. However, we found some support for the third hypothesis. The maximum size of perch was positively correlated with lake size, and the majority (88 %) of very large pikes (>10 kg) were caught from lakes with the area > 1 km2, indicating habitat size importance for large predators.
{"title":"Littoral resources, food chain length and top predator size - Are these connected with lake size?","authors":"Paula Kankaala , Kimmo K. Kahilainen , Mikko Olin , Antti J. Rissanen","doi":"10.1016/j.fooweb.2024.e00379","DOIUrl":"10.1016/j.fooweb.2024.e00379","url":null,"abstract":"<div><div>The size of a lake ecosystem sets many direct and indirect physical limits for habitats available for different food web compartments as well as the taxa inhabiting these. We tested the hypotheses that 1) reliance of fish on littoral resources increase in lakes with shoreline development, and 2) food chain length and 3) top predator size increase with lake size. We analyzed food web trophic structure, based on stable isotope analyses (SIA) of carbon (δ<sup>13</sup>C) and nitrogen (δ<sup>15</sup>N), in six boreal lakes in southern and eastern Finland (area 0.13–567 km<sup>2</sup>). We also applied data from gillnet monitoring of two common predatory fish, perch (<em>Perca fluviatilis</em>) and pike (<em>Esox lucius</em>), in >100 lakes as well as data from national large pike (weight > 10 kg) competition. Our results based on SIA did not support the first two hypotheses. Mixing-model results indicated great contribution of littoral resources for many fish, however, showing considerable within-taxa variation for some species. Fish reliance on littoral resources was not directly related to lake shoreline development. The lakes had four trophic levels and large predators coupled both littoral and pelagic habitats. The very rare freshwater pinniped, Saimaa ringed seal (<em>Pusa hispida saimensis</em>), shared the same trophic position with piscivorous fish. However, we found some support for the third hypothesis. The maximum size of perch was positively correlated with lake size, and the majority (88 %) of very large pikes (>10 kg) were caught from lakes with the area > 1 km<sup>2</sup>, indicating habitat size importance for large predators.</div></div>","PeriodicalId":38084,"journal":{"name":"Food Webs","volume":"41 ","pages":"Article e00379"},"PeriodicalIF":1.8,"publicationDate":"2024-11-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142698521","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-11-10DOI: 10.1016/j.fooweb.2024.e00378
Javier A. Simonetti , Ana Paola Yusti-Muñoz , Matías N. González-Herrera , Ignacio Delgado Salinas , Darío Moreira-Arce
This study examines prey-carrying behavior in culpeo (Lycalopex culpaeus) and chilla (L. griseus) foxes within Chilean Patagonia's sheep farming lands. We used camera traps to register prey transportation. This behavior was more frequent during the reproductive season compared to the non-reproductive season, suggesting an association with pup-rearing activities. The presence of livestock guardian dogs and other predation control measures may also influence prey-carrying behavior, particularly in L. culpaeus, as foxes might adjust their activities in response to perceived risks. This research provides initial evidence of prey transport in these fox species and highlights the need for further study to understand its ecological implications and interactions with livestock management practices.
{"title":"Prey-carrying behavior of Lycalopex foxes in Chilean Patagonia","authors":"Javier A. Simonetti , Ana Paola Yusti-Muñoz , Matías N. González-Herrera , Ignacio Delgado Salinas , Darío Moreira-Arce","doi":"10.1016/j.fooweb.2024.e00378","DOIUrl":"10.1016/j.fooweb.2024.e00378","url":null,"abstract":"<div><div>This study examines prey-carrying behavior in culpeo (<em>Lycalopex culpaeus</em>) and chilla (<em>L. griseus</em>) foxes within Chilean Patagonia's sheep farming lands. We used camera traps to register prey transportation. This behavior was more frequent during the reproductive season compared to the non-reproductive season, suggesting an association with pup-rearing activities. The presence of livestock guardian dogs and other predation control measures may also influence prey-carrying behavior, particularly in L. <em>culpaeus,</em> as foxes might adjust their activities in response to perceived risks. This research provides initial evidence of prey transport in these fox species and highlights the need for further study to understand its ecological implications and interactions with livestock management practices.</div></div>","PeriodicalId":38084,"journal":{"name":"Food Webs","volume":"41 ","pages":"Article e00378"},"PeriodicalIF":1.8,"publicationDate":"2024-11-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142654631","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-11-09DOI: 10.1016/j.fooweb.2024.e00373
Liliana V. Vassileva , Lyudmila Lozanova , Martin P. Marinov , Jérôme Morinière , Boyko Neov , Boris P. Nikolov , Nikolay Simov , Stefania Klayn
Migratory waders use stopover sites to refuel for the next stages of their migration, relying on seasonally abundant prey. Migration success depends on food quality and availability at these key sites. We studied the diet composition and preferences of the Grey Plover (Pluvialis squatarola) at its migration stopover at Pomorie Lake on the South-Western Black Sea coast, Bulgaria through DNA metabarcoding of faeces collected in autumn 2020 and spring 2021. Prey availability samples were also collected from the surf zone and the supralittoral sandy shore habitats in the study area.
Grey Plover had a broad diet spectrum, with 332 prey taxa in total identified by metabarcoding. Both terrestrial and marine taxa were found, suggesting that the birds use multiple coastal habitats for foraging. Terrestrial arthropods, particularly insects, predominated in the Grey Plover diet; mytilid bivalves were the most represented marine taxon. The birds had a generalist feeding strategy, with diverse prey items eaten in small quantities. Most Grey Plovers fed on insects (Diptera, Lepidoptera, Hymenoptera), but some individuals showed specialisation for other taxa (mussels, spiders, polychaetes). The most abundant potential prey in the environment were not the most frequently consumed, but it is possible the prey sampling failed to capture the whole spectrum of available prey due to methodological limitations.
We found no significant seasonal variation in Grey Plover diet composition, but the proportions of some prey taxa in the diet changed slightly, probably reflecting seasonal differences in their abundance and activity in coastal habitats.
Our results contribute to the knowledge of Grey Plover diet, prey choice and habitat use in a little-studied region, and could help design effective conservation measures to preserve habitat quality at stopover sites for this wader and others with similar ecology.
{"title":"Prey availability and diet composition of the Grey plover (Pluvialis squatarola) during migration on the South-Western Black Sea coast, Bulgaria","authors":"Liliana V. Vassileva , Lyudmila Lozanova , Martin P. Marinov , Jérôme Morinière , Boyko Neov , Boris P. Nikolov , Nikolay Simov , Stefania Klayn","doi":"10.1016/j.fooweb.2024.e00373","DOIUrl":"10.1016/j.fooweb.2024.e00373","url":null,"abstract":"<div><div>Migratory waders use stopover sites to refuel for the next stages of their migration, relying on seasonally abundant prey. Migration success depends on food quality and availability at these key sites. We studied the diet composition and preferences of the Grey Plover (<em>Pluvialis squatarola</em>) at its migration stopover at Pomorie Lake on the South-Western Black Sea coast, Bulgaria through DNA metabarcoding of faeces collected in autumn 2020 and spring 2021. Prey availability samples were also collected from the surf zone and the supralittoral sandy shore habitats in the study area.</div><div>Grey Plover had a broad diet spectrum, with 332 prey taxa in total identified by metabarcoding. Both terrestrial and marine taxa were found, suggesting that the birds use multiple coastal habitats for foraging. Terrestrial arthropods, particularly insects, predominated in the Grey Plover diet; mytilid bivalves were the most represented marine taxon. The birds had a generalist feeding strategy, with diverse prey items eaten in small quantities. Most Grey Plovers fed on insects (Diptera, Lepidoptera, Hymenoptera), but some individuals showed specialisation for other taxa (mussels, spiders, polychaetes). The most abundant potential prey in the environment were not the most frequently consumed, but it is possible the prey sampling failed to capture the whole spectrum of available prey due to methodological limitations.</div><div>We found no significant seasonal variation in Grey Plover diet composition, but the proportions of some prey taxa in the diet changed slightly, probably reflecting seasonal differences in their abundance and activity in coastal habitats.</div><div>Our results contribute to the knowledge of Grey Plover diet, prey choice and habitat use in a little-studied region, and could help design effective conservation measures to preserve habitat quality at stopover sites for this wader and others with similar ecology.</div></div>","PeriodicalId":38084,"journal":{"name":"Food Webs","volume":"41 ","pages":"Article e00373"},"PeriodicalIF":1.8,"publicationDate":"2024-11-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142654632","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-11-07DOI: 10.1016/j.fooweb.2024.e00377
Julián A. Rojas-Morales , Jose J. Henao-Osorio , Didier Álvarez López , Néstor Sánchez-Guillén
Riparian food webs are linked by cross-boundary resource fluxes, including the consumption of terrestrial invertebrates and vertebrates by fish and the consumption of aquatic vertebrates by terrestrial invertebrates, mostly arachnids. Amblypygids prey upon a wide array of vertebrates, but no records on fishes are known. Here we report an interesting predation event of an adult Heterophrynus sp., upon a catfish Astroblepus sp. in the Rio Manso, northern Andes of Colombia, and summarized the published information of trophic interactions of this river in a food web framework. A high prey-size ratio (0.87) respect to Heterophrynus sp., highlight that fishes could represent an important food item for amblypygids. This datum, besides other published before, indicates that the consumption of terrestrial and aquatic vertebrates by terrestrial invertebrates can be a substantial cross-boundary flux link in tropical montane streams deserving future ecological studies.
{"title":"Joining to the web. Predation of Heterophrynus sp. (Amblypygi: Phrynidae) on a catfish Astroblepus sp. (Siluriformes: Astroblepidae), in a premontane river of the northern Andes of Colombia","authors":"Julián A. Rojas-Morales , Jose J. Henao-Osorio , Didier Álvarez López , Néstor Sánchez-Guillén","doi":"10.1016/j.fooweb.2024.e00377","DOIUrl":"10.1016/j.fooweb.2024.e00377","url":null,"abstract":"<div><div>Riparian food webs are linked by cross-boundary resource fluxes, including the consumption of terrestrial invertebrates and vertebrates by fish and the consumption of aquatic vertebrates by terrestrial invertebrates, mostly arachnids. Amblypygids prey upon a wide array of vertebrates, but no records on fishes are known. Here we report an interesting predation event of an adult <em>Heterophrynus</em> sp., upon a catfish <em>Astroblepus</em> sp. in the Rio Manso, northern Andes of Colombia, and summarized the published information of trophic interactions of this river in a food web framework. A high prey-size ratio (0.87) respect to <em>Heterophrynus</em> sp., highlight that fishes could represent an important food item for amblypygids. This datum, besides other published before, indicates that the consumption of terrestrial and aquatic vertebrates by terrestrial invertebrates can be a substantial cross-boundary flux link in tropical montane streams deserving future ecological studies.</div></div>","PeriodicalId":38084,"journal":{"name":"Food Webs","volume":"41 ","pages":"Article e00377"},"PeriodicalIF":1.8,"publicationDate":"2024-11-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142654207","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-11-06DOI: 10.1016/j.fooweb.2024.e00376
Shahid Afzal, Wasim Ahmad
The bottom-up effects of vegetation are widely recognized as important factors influencing the structure and functioning of soil food webs in forests. However, the influence of forest type on the composition and stability of soil nematode communities remains underexplored. In this study, we investigated the abundance, composition, diversity, and various aspects of soil nematode communities across three distinct forest types - Sub-tropical Pine Forests (STPF), Himalayan Moist Temperate Forests (HMTF), and Himalayan Dry Temperate Forests (HDTF) - during two seasons (summer and autumn). In both summer and autumn, total nematode abundance and the abundance of bacterivores were significantly higher in STPF compared to the other two forest types. Taxonomic diversity, as indicated by the Simpson index, was also greater in STPF during both seasons. The higher maturity index and sigma maturity index values observed in STPF suggest a more stable nematode community in the summer season. The soil nematode faunal profile indicated an enriched and structured food web in STPF across both seasons. Additionally, the metabolic footprint of the entire nematode community was considerably higher in STPF during the summer. Overall, soil nematode communities were most stable in STPF and least stable in HDTF. Our findings suggest that the Sub-tropical Pine Forests in the Pir-Panjal mountain range, across two contrasting seasons, support a higher level of soil food web structure and more complex soil biological communities than the other forest types. This study provides a foundation for understanding soil food web structure, function, and seasonal stability, which has important implications for sustainable forest management.
{"title":"Temporal and spatial variations of soil nematode assemblages across distinct forest ecosystems","authors":"Shahid Afzal, Wasim Ahmad","doi":"10.1016/j.fooweb.2024.e00376","DOIUrl":"10.1016/j.fooweb.2024.e00376","url":null,"abstract":"<div><div>The bottom-up effects of vegetation are widely recognized as important factors influencing the structure and functioning of soil food webs in forests. However, the influence of forest type on the composition and stability of soil nematode communities remains underexplored. In this study, we investigated the abundance, composition, diversity, and various aspects of soil nematode communities across three distinct forest types - Sub-tropical Pine Forests (STPF), Himalayan Moist Temperate Forests (HMTF), and Himalayan Dry Temperate Forests (HDTF) - during two seasons (summer and autumn). In both summer and autumn, total nematode abundance and the abundance of bacterivores were significantly higher in STPF compared to the other two forest types. Taxonomic diversity, as indicated by the Simpson index, was also greater in STPF during both seasons. The higher maturity index and sigma maturity index values observed in STPF suggest a more stable nematode community in the summer season. The soil nematode faunal profile indicated an enriched and structured food web in STPF across both seasons. Additionally, the metabolic footprint of the entire nematode community was considerably higher in STPF during the summer. Overall, soil nematode communities were most stable in STPF and least stable in HDTF. Our findings suggest that the Sub-tropical Pine Forests in the Pir-Panjal mountain range, across two contrasting seasons, support a higher level of soil food web structure and more complex soil biological communities than the other forest types. This study provides a foundation for understanding soil food web structure, function, and seasonal stability, which has important implications for sustainable forest management.</div></div>","PeriodicalId":38084,"journal":{"name":"Food Webs","volume":"41 ","pages":"Article e00376"},"PeriodicalIF":1.8,"publicationDate":"2024-11-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142654206","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-11-03DOI: 10.1016/j.fooweb.2024.e00375
G. Bradley Smith , Jody M. Tucker , Mourad Gabriel , Greta Wengert , Jonathan N. Pauli
Niche partitioning is critical for the stable coexistence of competing species that share limited resources. Yet, niches are dynamic, especially in the face of rapid environmental change. Carnivores exhibit particularly strong forms of competition and are differentially affected by change. Fishers (Pekania pennanti) and martens (Martes caurina) are two species of carnivores that overlap in space, time, and resources. In the Sierra Nevada of California, these two species share habitats that are undergoing a sudden restructuring due to drought and the subsequent mortality of more than half of all trees. Using a long-term dataset from across the affected region of the Sierra Nevada, we quantified the diet, as well as dietary niche overlap and niche shift of fishers and martens during summer months before, during, and after these disturbances and as a function of spatial overlap. The summer diet of fishers and martens did not appear to be affected by change in live forest canopy and tree mortality. While fisher diet was unaffected by elevation, martens exhibited an increasing reliance on vertebrate prey at higher elevations. Our results suggest that during summer months the diet of fishers is highly diverse, even including fungi and insects, but the diet of martens is less diverse and more reliant on vertebrate prey. These different consumption patterns — which were largely unaffected by changing environmental conditions, except elevation — have led to unexpectedly low overlap in trophic niche space during the timeframe measured. Our findings demonstrate that the coexistence of martens and fishers regionally is likely facilitated, in part, through partitioning along the trophic niche axis. If drought conditions persist and lead to continued or increasingly reduced snowpack and altered vegetation, future research should assess how niche partitioning of fishers, martens, and other members of the broader carnivore community will endure.
{"title":"Dietary partitioning of fishers and martens in a rapidly changing landscape","authors":"G. Bradley Smith , Jody M. Tucker , Mourad Gabriel , Greta Wengert , Jonathan N. Pauli","doi":"10.1016/j.fooweb.2024.e00375","DOIUrl":"10.1016/j.fooweb.2024.e00375","url":null,"abstract":"<div><div>Niche partitioning is critical for the stable coexistence of competing species that share limited resources. Yet, niches are dynamic, especially in the face of rapid environmental change. Carnivores exhibit particularly strong forms of competition and are differentially affected by change. Fishers (<em>Pekania pennanti</em>) and martens (<em>Martes caurina</em>) are two species of carnivores that overlap in space, time, and resources. In the Sierra Nevada of California, these two species share habitats that are undergoing a sudden restructuring due to drought and the subsequent mortality of more than half of all trees. Using a long-term dataset from across the affected region of the Sierra Nevada, we quantified the diet, as well as dietary niche overlap and niche shift of fishers and martens during summer months before, during, and after these disturbances and as a function of spatial overlap. The summer diet of fishers and martens did not appear to be affected by change in live forest canopy and tree mortality. While fisher diet was unaffected by elevation, martens exhibited an increasing reliance on vertebrate prey at higher elevations. Our results suggest that during summer months the diet of fishers is highly diverse, even including fungi and insects, but the diet of martens is less diverse and more reliant on vertebrate prey. These different consumption patterns — which were largely unaffected by changing environmental conditions, except elevation — have led to unexpectedly low overlap in trophic niche space during the timeframe measured. Our findings demonstrate that the coexistence of martens and fishers regionally is likely facilitated, in part, through partitioning along the trophic niche axis. If drought conditions persist and lead to continued or increasingly reduced snowpack and altered vegetation, future research should assess how niche partitioning of fishers, martens, and other members of the broader carnivore community will endure.</div></div>","PeriodicalId":38084,"journal":{"name":"Food Webs","volume":"41 ","pages":"Article e00375"},"PeriodicalIF":1.8,"publicationDate":"2024-11-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142654205","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-11-03DOI: 10.1016/j.fooweb.2024.e00374
Ayessa Rosa-Oliveira , Cristiano Lopes-Andrade
Mycophagy, the practice of feeding on fungal structures or plant material decomposed by fungal enzymes, is one of the oldest feeding habits of beetles. A notable family of beetles with a strict association with fungi throughout their life cycle is Ciidae. Members of this family use fungi as shelter, food, and sites for copulation and oviposition, making them true mycetobionts. The fungi associated with ciids belong to the phylum Basidiomycota and play a crucial role in nutrient cycling by degrading wood and decomposing cellulose, hemicellulose, and lignin. Ciids contribute significantly to the degradation of these basidiomes, thereby preventing their accumulation and enhancing nutrient availability in forest ecosystems. Although interactions between Ciidae beetles and their host fungi have been relatively well-studied, research on these interactions in the neotropics remains scarce. In this study, we investigated the interactions between ciids and their host fungi in two forest remnants of the Atlantic Forest biome. Using ecological network analysis, we assessed the frequency of occurrence of ciid species and calculated key indices for describing community structure: connectance, web asymmetry, links per species, nestedness, robustness, and specialization. This allowed us to compare the structural patterns of the two Ciidae-fungi networks. Our results revealed that the main host fungal species were the same in both communities, but differences in host usage by ciids were observed, reflecting the availability of fungal basidiomes. These differences led to distinct network structures. Most Ciidae species were found to be generalists, exploiting host fungi according to their availability.
{"title":"Specialization in Ciidae-host fungi communities in two Atlantic forest remnants of Southeast Brazil","authors":"Ayessa Rosa-Oliveira , Cristiano Lopes-Andrade","doi":"10.1016/j.fooweb.2024.e00374","DOIUrl":"10.1016/j.fooweb.2024.e00374","url":null,"abstract":"<div><div>Mycophagy, the practice of feeding on fungal structures or plant material decomposed by fungal enzymes, is one of the oldest feeding habits of beetles. A notable family of beetles with a strict association with fungi throughout their life cycle is Ciidae. Members of this family use fungi as shelter, food, and sites for copulation and oviposition, making them true mycetobionts. The fungi associated with ciids belong to the phylum Basidiomycota and play a crucial role in nutrient cycling by degrading wood and decomposing cellulose, hemicellulose, and lignin. Ciids contribute significantly to the degradation of these basidiomes, thereby preventing their accumulation and enhancing nutrient availability in forest ecosystems. Although interactions between Ciidae beetles and their host fungi have been relatively well-studied, research on these interactions in the neotropics remains scarce. In this study, we investigated the interactions between ciids and their host fungi in two forest remnants of the Atlantic Forest biome. Using ecological network analysis, we assessed the frequency of occurrence of ciid species and calculated key indices for describing community structure: connectance, web asymmetry, links per species, nestedness, robustness, and specialization. This allowed us to compare the structural patterns of the two Ciidae-fungi networks. Our results revealed that the main host fungal species were the same in both communities, but differences in host usage by ciids were observed, reflecting the availability of fungal basidiomes. These differences led to distinct network structures. Most Ciidae species were found to be generalists, exploiting host fungi according to their availability.</div></div>","PeriodicalId":38084,"journal":{"name":"Food Webs","volume":"41 ","pages":"Article e00374"},"PeriodicalIF":1.8,"publicationDate":"2024-11-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142593705","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-10-29DOI: 10.1016/j.fooweb.2024.e00372
Kira L. Allen , Kristy A. Lewis
Estuarine ecosystems often support large populations of forage fish, but these small-medium sized fish and the predators they feed may be affected by multiple climate change and human-induced stressors. In the Apalachicola Bay estuary, Florida, USA, reduced freshwater inflow and sea level rise are two prevalent stressors, and little is known about how these environmental changes might impact the forage fish species who inhabit the estuary. This study uses a food web model for Apalachicola Bay to simulate the impacts of future changes in water temperature and salinity on forage fish and predator species who inhabit the estuary. Water temperature and salinity conditions were based on previously developed simulations of reduced freshwater inflow and sea level rise in Apalachicola Bay from 2020 to 2049. These simulated environmental changes were applied as forcing functions in the food web model to drive shifts in species biomasses over time. This study centered on changes in biomass for two highly abundant forage fish species, juvenile silver perch (Bairdiella chrysoura) and juvenile pinfish (Lagodon rhomboides), as well as their major predators, spotted seatrout (Cynoscion nebulosus) and inshore lizardfish (Synodus foetens). These changes were assessed at both 10- and 30-year time intervals relative to 2019, along with an examination of forage fish consumption by their predators. Juvenile silver perch biomass increased across all scenarios and time scales, while juvenile pinfish biomass decreased. Consumption of juvenile silver perch by spotted seatrout increased across all scenarios and time scales, and consumption of juvenile pinfish by inshore lizardfish decreased, in concordance with the trends in prey biomass. Both spotted seatrout and inshore lizardfish biomasses decreased across future scenarios, though the high biomass of juvenile silver perch may have played a role in stabilizing the decline of spotted seatrout. Changes in forage fish biomasses and their impacts on predator species as a result of reduced freshwater inflow and sea level rise have implications for ecosystem productivity and the fisheries of the region.
{"title":"Future impacts of reduced freshwater inflow and sea level rise on forage fish and their predators in Apalachicola Bay, Florida","authors":"Kira L. Allen , Kristy A. Lewis","doi":"10.1016/j.fooweb.2024.e00372","DOIUrl":"10.1016/j.fooweb.2024.e00372","url":null,"abstract":"<div><div>Estuarine ecosystems often support large populations of forage fish, but these small-medium sized fish and the predators they feed may be affected by multiple climate change and human-induced stressors. In the Apalachicola Bay estuary, Florida, USA, reduced freshwater inflow and sea level rise are two prevalent stressors, and little is known about how these environmental changes might impact the forage fish species who inhabit the estuary. This study uses a food web model for Apalachicola Bay to simulate the impacts of future changes in water temperature and salinity on forage fish and predator species who inhabit the estuary. Water temperature and salinity conditions were based on previously developed simulations of reduced freshwater inflow and sea level rise in Apalachicola Bay from 2020 to 2049. These simulated environmental changes were applied as forcing functions in the food web model to drive shifts in species biomasses over time. This study centered on changes in biomass for two highly abundant forage fish species, juvenile silver perch (<em>Bairdiella chrysoura</em>) and juvenile pinfish (<em>Lagodon rhomboides</em>), as well as their major predators, spotted seatrout (<em>Cynoscion nebulosus</em>) and inshore lizardfish (<em>Synodus foetens</em>). These changes were assessed at both 10- and 30-year time intervals relative to 2019, along with an examination of forage fish consumption by their predators. Juvenile silver perch biomass increased across all scenarios and time scales, while juvenile pinfish biomass decreased. Consumption of juvenile silver perch by spotted seatrout increased across all scenarios and time scales, and consumption of juvenile pinfish by inshore lizardfish decreased, in concordance with the trends in prey biomass. Both spotted seatrout and inshore lizardfish biomasses decreased across future scenarios, though the high biomass of juvenile silver perch may have played a role in stabilizing the decline of spotted seatrout. Changes in forage fish biomasses and their impacts on predator species as a result of reduced freshwater inflow and sea level rise have implications for ecosystem productivity and the fisheries of the region.</div></div>","PeriodicalId":38084,"journal":{"name":"Food Webs","volume":"41 ","pages":"Article e00372"},"PeriodicalIF":1.8,"publicationDate":"2024-10-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142654630","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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