scholarly journals Do Roads Alter the Trophic Behavior of the Mesocarnivore Community Living Close to Them?

Diversity ◽  
2021 ◽  
Vol 13 (4) ◽  
pp. 173
Author(s):  
Pablo Ruiz-Capillas ◽  
Cristina Mata ◽  
Beatriz Fernández ◽  
Carlos Fernandes ◽  
Juan E. Malo

Roads have impacts on the fauna arising from habitat fragmentation, roadkill and the barrier effect. Furthermore, roads lead species to change their activity with repercussions on predator–prey interactions and trigger indirect effects that are currently unknown. This study analyzes the effect of a motorway on the trophic behavior of the terrestrial carnivore community of its surroundings. Monthly scat sampling was conducted over a year at three distances from a motorway (0–50 m, 500–550 m and 1000–1050 m). We collected 498 scats, these originating from red fox (39.16%), cat (24.50%), stone marten (24.09%) and badger (12.25%). The relative abundance of the trophic resources in them was estimated together with the trophic diversity and niche overlap of the carnivore species. The results showed a distinct effect of distance from the road on trophic behavior of carnivores, as well as differences between species and seasons. The scats nearest the road had 10–20% more biomass of small mammals, equivalent in relative terms to a 21–48% increase in small mammals’ biomass when compared with scats collected further from the road. This finding indicates changes in predator–prey interactions near the road and shows that the human-generated structural and functional changes to ecosystems spread throughout trophic networks.

2021 ◽  
Vol 12 ◽  
Author(s):  
Jun Zhang ◽  
Pengcheng Xing ◽  
Mengyu Niu ◽  
Gehong Wei ◽  
Peng Shi

As the main consumers of bacteria and fungi in farmed soils, protists remain poorly understood. The aim of this study was to explore protist community assembly and ecological roles in soybean fields. Here, we investigated differences in protist communities using high-throughput sequencing and their inferred potential interactions with bacteria and fungi between the bulk soil and rhizosphere compartments of three soybean cultivars collected from six ecological regions in China. Distinct protist community structures characterized the bulk soil and rhizosphere of soybean plants. A significantly higher relative abundance of phagotrophs was observed in the rhizosphere (25.1%) than in the bulk soil (11.3%). Spatial location (R2 = 0.37–0.51) explained more of the variation in protist community structures of soybean fields than either the compartment (R2 = 0.08–0.09) or cultivar type (R2 = 0.02–0.03). The rhizosphere protist network (76 nodes and 414 edges) was smaller and less complex than the bulk soil network (147 nodes and 880 edges), indicating a smaller potential of niche overlap and interactions in the rhizosphere due to the increased resources in the rhizosphere. Furthermore, more inferred potential predator-prey interactions occur in the rhizosphere. We conclude that protists have a crucial ecological role to play as an integral part of microbial co-occurrence networks in soybean fields.


PLoS ONE ◽  
2021 ◽  
Vol 16 (3) ◽  
pp. e0247400
Author(s):  
Manisha Bhardwaj ◽  
Kylie Soanes ◽  
José J. Lahoz-Monfort ◽  
Linda F. Lumsden ◽  
Rodney van der Ree

Traffic disturbances (i.e. pollution, light, noise, and vibrations) often extend into the area surrounding a road creating a ‘road-effect zone’. Habitat within the road-effect zone is degraded or, in severe cases, completely unsuitable for wildlife, resulting in indirect habitat loss. This can have a disproportionate impact on wildlife in highly modified landscapes, where remaining habitat is scarce or occurs predominantly along roadside reserves. In this study, we investigated the road-effect zone for insectivorous bats in highly cleared agricultural landscapes by quantifying the change in call activity with proximity to three major freeways. The activity of seven out of 10 species of bat significantly decreased with proximity to the freeway. We defined the road-effect zone to be the proximity at which call activity declined by at least 20% relative to the maximum detected activity. The overall road-effect zone for bats in this region was 307 m, varying between 123 and 890 m for individual species. Given that this road-effect zone exceeds the typical width of the roadside verges (<50 m), it is possible that much of the vegetation adjacent to freeways in this and similar landscapes provides low-quality habitat for bats. Without accounting for the road-effect zone, the amount of habitat lost or degraded due to roads is underestimated, potentially resulting in the loss of wildlife, ecosystem services and key ecosystem processes (e.g. predator-prey or plant-pollinator interactions) from the landscape. We suggest all future environmental impact assessments include quantifying the road-effect zone for sensitive wildlife, in order to best plan and mitigate the impact of roads on the environment. Mitigating the effects of new and existing roads on wildlife is essential to ensure enough high-quality habitat persists to maintain wildlife populations.


2011 ◽  
Vol 6 (4) ◽  
pp. 375-386 ◽  
Author(s):  
Emerson M. VIEIRA ◽  
Gabriela PAISE

PLoS ONE ◽  
2016 ◽  
Vol 11 (3) ◽  
pp. e0151500 ◽  
Author(s):  
Fernando Ascensão ◽  
Cristina Mata ◽  
Juan E. Malo ◽  
Pablo Ruiz-Capillas ◽  
Catarina Silva ◽  
...  

1959 ◽  
Vol 91 (7) ◽  
pp. 385-398 ◽  
Author(s):  
C. S. Holling

In an earlier study (Holling, 1959) the basic and subsidiary components of predation were demonstrated in a predator-prey situation involving the predation of sawfly cocoons by small mammals. One of the basic components, termed the functional response, was a response of the consumption of prey by individual predators to changes of prey density, and it appeared to be at least theoretically important in population regulation: Because of this importance the functional response has been further examined in an attempt to explain its characteristics.


2018 ◽  
Vol 78 (1) ◽  
Author(s):  
Yesely M. Hurtado ◽  
Cesar E. Tamaris-Turizo ◽  
Manuel J. López Rodriguez ◽  
J. Manuel Tierno de Figueroa

The knowledge of the diet of aquatic insects is important to assess the use of resources and overlap of trophic niche between species, as well as to understand their role in the food web of the freshwater ecosystems they inhabit. This is particularly necessary in tropical areas where information on this topic is scarce. The aim of the present work is to describe the feeding habits of the species Anacroneuria marta Zúñiga and Stark, 2002 and Anacroneuria caraca Stark, 1995 in the middle section of the Gaira River (Sierra Nevada de Santa Marta, Colombia). We performed three samplings during the rainy and dry seasons in the two main different microhabitats of the reach (leaf packs and gravel) in 2014. The diet of a total of 87 and 90 individuals of A. caraca and A. marta, respectively, was studied. With this information, niche breadth for each species and niche overlap between them in terms of trophic resources were calculated. The main trophic resource for both species in the dry and rainy season was the animal matter. In the dry season, FPOM was also important in the diet of A. caraca, and A. marta ingested a great quantity of CPOM in the rainy season. Larvae of Trichoptera, were the most ingested prey in both species, followed by Chironomidae, Coleoptera Hydrophilidae, and Ephemeroptera. No differences in diet between both species were detected, so this could favor the niche overlap in terms of trophic resources and could lead to competition between them. The possible ecological scenarios are discussed.


2014 ◽  
Vol 74 (2) ◽  
pp. 363-370 ◽  
Author(s):  
CMM. Butakka ◽  
FH. Ragonha ◽  
AM. Takeda

The niche overlap between trophic groups of Chironomidae larvae in different habitats was observed between trophic groups and between different environments in Neotropical floodplain. For the evaluation we used the index of niche overlap (CXY) and analysis of trophic networks, both from the types and amount of food items identified in the larval alimentary canal. In all environments, the larvae fed on mainly organic matter such as plants fragments and algae, but there were many omnivore larvae. Species that have high values of food items occurred in diverse environments as generalists with great overlap niche and those with a low amount of food items with less overlap niche were classified as specialists. The largest number of trophic niche overlap was observed among collector-gatherers in connected floodplain lakes. The lower values of index niche overlap were predators. The similarity in the diet of different taxa in the same niche does not necessarily imply competition between them, but coexistence when the food resource is not scarce in the environment even in partially overlapping niches.


Oryx ◽  
2015 ◽  
Vol 50 (3) ◽  
pp. 474-479 ◽  
Author(s):  
Anne-Marie C. Hodge ◽  
Brian S. Arbogast

AbstractEcuador harbours a diverse assemblage of tropical mammals, yet the natural history and local-scale distributions of many species remain poorly understood. We conducted the first systematic camera-trap survey of terrestrial mammalian carnivores at Wildsumaco Wildlife Sanctuary, a mid-elevation (1,250–1,450 m), montane rainforest site on the slopes of Sumaco Volcano, in the heart of the Tropical Andes biodiversity hotspot. We quantified trap success, latency to detection and temporal activity patterns for each species detected. We recorded nine carnivore species (four felids, two procyonids and three mustelids), including the first verified record of the jaguarundi Puma yagouaroundi in the region. These species comprise one-third of all terrestrial carnivore species known to occur in Ecuador and 82% of those thought to occur at mid-elevation. All except one of the carnivores we detected have reported elevational ranges ≤ 1,500 m; the one exception, the puma Puma concolor, occurs throughout mainland Ecuador at 0–4,500 m. No cloud forest or highland species (i.e. those with a reported lower elevational limit of ≥ 1,500 m) were detected. Trap success was highest, and latency to detection smallest, for the margay Leopardis wiedii, and temporal activity patterns for all species were consistent with those reported previously in the literature. Our results demonstrate that the mid-elevation montane rainforests of Sumaco Volcano support an exceptionally high diversity of co-existing mammalian carnivores, many of which appear to be near their upper elevational limits, and emphasize the conservation value of this area.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Todd M. Kautz ◽  
Dean E. Beyer ◽  
Zachary Farley ◽  
Nicholas L. Fowler ◽  
Kenneth F. Kellner ◽  
...  

AbstractWhere two sympatric species compete for the same resource and one species is dominant, there is potential for the subordinate species to be affected through interference competition or energetic costs of avoiding predation. Fishers (Pekania pennanti) and American martens (Martes americana) often have high niche overlap, but fishers are considered dominant and potentially limiting to martens. We observed presence and vigilance of fishers and martens at winter carcass sites using remote cameras in Michigan, USA, to test the hypothesis that interference competition from fishers creates a landscape of fear for martens. Within winters, fishers co-occupied 78–88% of sites occupied by martens, and martens co-occupied 79–88% of sites occupied by fishers. Fishers displaced martens from carcasses during 21 of 6117 marten visits, while martens displaced fishers during 0 of 1359 fisher visits. Martens did not alter diel activity in response to fisher use of sites. Martens allocated 37% of time to vigilance compared to 23% for fishers, and martens increased vigilance up to 8% at sites previously visited by fishers. Fishers increased vigilance by up to 8% at sites previously visited by martens. Our results indicate that fishers were dominant over martens, and martens had greater baseline perception of risk than fishers. However, fishers appeared to be also affected as the dominant competitor by putting effort into scanning for martens. Both species appeared widespread and common in our study area, but there was no evidence that fishers spatially or temporally excluded martens from scavenging at carcasses other than occasional short-term displacement when a fisher was present. Instead, martens appeared to mitigate risk from fishers by using vigilance and short-term avoidance. Multiple short-term anti-predator behaviors within a landscape of fear may facilitate coexistence among carnivore species.


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