scholarly journals Predation risk is a function of seasonality rather than habitat complexity in a tropical semiarid forest

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Anthony Santana Ferreira ◽  
Renato Gomes Faria
Keyword(s):  
Predation Risk ◽  
Species Interactions ◽  
Structural Complexity ◽  
The Body ◽  
Northeastern Brazil ◽  
Arid Environments ◽  
Ecological Processes ◽  
Important Species ◽  
Predator Prey ◽  
Natural Monument

AbstractPredator–prey dynamics are some of the most important species’ interactions in the natural structuring of communities, and are among the more complex ecological processes studied by ecologists. We measured predation risk using artificial lizard replicas to test two competing hypotheses regarding predation pressure in semi-arid environments: (1) predation risk is dependent on the habitat structural complexity; and (2) predation risk is dependent on seasonality. We placed 960 lizard replicas along three sites with different physical structures and in both dry and rainy seasons for seven consecutive days in a caatinga area in northeastern Brazil at Grota do Angico Natural Monument (GANM). Birds were responsible for the majority of attacks and more frequently on artificial lizards placed in trees. Attacks focused on the most vulnerable areas of the body (head and torso), proving that were perceived by predators as true prey items. We found that predation risk is not dependent on the habitat structural complexity, but rather dependent on the caatinga seasonality, with the overall attack rate being 19% higher in the dry season. Our study suggests that potential predation risk is highly context-dependent and that seasonality consistently drives of trophic interactions strength in the caatinga, an important ecological finding that could contribute to better understanding the complex evolution of predator–prey interactions within communities of animals living in different habitats.

scholarly journals Predation Risk is a Function of Seasonality Rather than Habitat Complexity in a Tropical Semi-arid Forest

2021 ◽  
Author(s):  
Anthony Ferreira ◽  
Renato Faria
Keyword(s):  
Predation Risk ◽  
Species Interactions ◽  
Structural Complexity ◽  
The Body ◽  
Northeastern Brazil ◽  
Arid Environments ◽  
Ecological Processes ◽  
Important Species ◽  
Predator Prey ◽  
Semi Arid

Abstract Predator-prey dynamic is one of the most important species’ interactions in the natural structuring of communities, and is among the more complex ecological processes studied by ecologists. We measure predation risk using artificial lizard replicas to test two competing hypotheses regarding predation pressure in semi-arid environments: (1) predation risk is dependent on the habitat structural complexity; and (2) predation risk is dependent on seasonality. We placed 960 replicas along three sites with different physical structures and in both seasons for seven consecutive days in a caatinga area in northeastern Brazil. Birds were responsible for the majority of attacks and more frequently on artificial lizards placed in trees. Attacks focused on the most vulnerable areas of the body (head and torso), proving that were perceived by predators as true prey items. We found that predation risk is not dependent on the habitat structural complexity, but rather dependent on the caatinga seasonality, with the overall attack being 19% higher in the dry season. Our study suggests that potential predation risk is highly context-dependent and that seasonality consistently drives of trophic interactions strength in the caatinga, an important ecological finding that could contribute to better understanding the complex evolution of predator-prey interactions within communities of animals living in different habitats.

scholarly journals Ethnobotany in Intermedical Spaces: The Case of the Fulni-ô Indians (Northeastern Brazil)

2012 ◽  
Vol 2012 ◽  
pp. 1-13 ◽  
Author(s):  
Gustavo Taboada Soldati ◽  
Ulysses Paulino de Albuquerque
Keyword(s):  
Secondary Data ◽  
Medical System ◽  
The Body ◽  
Northeastern Brazil ◽  
Important Species ◽  
Cultural Sustainability ◽  
Botanical Knowledge ◽  
Therapeutic Uses ◽  
Local Practices ◽  
Traditional Botanical Knowledge

We analyzed the Fulni-ô medical system and introduced its intermedical character based on secondary data published in the literature. Then we focused on the medicinal plants known to the ethnic group, describing the most important species, their therapeutic uses and the body systems attributed to them. We based this analysis on the field experience of the authors in the project Studies for the Environmental and Cultural Sustainability of the Fulni-ô Medical System: Office of Medicinal Plant Care. This traditional botanical knowledge was used to corroborate the hybrid nature of local practices for access to health. We show that intermedicality is a result not only of the meeting of the Fulni-ô medical system with Biomedicine but also of its meeting with other traditional systems. Finally, we discuss how traditional botanical knowledge may be directly related to the ethnogenesis process led by the Fulni-ô Indians in northeastern Brazil.

scholarly journals Using 3D micro-geomorphometry to quantify interstitial spaces of an oyster cluster

2019 ◽  
Author(s):  
Kwanmok Kim ◽  
Vincent Lecours ◽  
Peter C. Frederick
Keyword(s):  
Species Interactions ◽  
Point Cloud ◽  
Structural Complexity ◽  
Ecological Studies ◽  
Empirical Relationships ◽  
Predator Prey ◽  
Interstitial Volume ◽  
Curvature Measures ◽  
Technological Limitations

In ecology, it is assumed that the characteristics (e.g. shape, size) of interstitial spaces found in a variety of habitats affect the colonization of species, species interactions, and species composition. However, those characteristics have traditionally been difficult to measure due to technological limitations. In this study, we used the Structure-from-Motion (SfM) photogrammetry technique to measure the physical characteristics of interstitial spaces in a small oyster cluster. The point cloud (and mesh) of the oyster cluster derived from SfM photogrammetry was found to be accurate enough (mean error of 0.654 mm) to conduct 3D geomorphometric analyses. We present an example of measures of curvature, roughness, interstitial volume, surface area, and openness for three 3D interstitial spaces. The interpretation of those measures enabled establishing which interstitial spaces were the most likely to be used as a shelter for an average crab. Those spaces are characterized by smaller openness and higher roughness and curvature measures. This initial quantitative 3D characterization of an oyster cluster is the first step in establishing empirical relationships between structural complexity of biological structures like oyster clusters and their ecological role for instance in predator-prey interactions. Overall, this study demonstrates the feasibility of combining SfM photogrammetry with geomorphometry for fine-scale ecological studies.

Training barn owls: a powerful tool in ecological experiments

2016 ◽  
Vol 62 (3-4) ◽  
pp. 149-154
Author(s):  
Aziz Subach
Keyword(s):  
Predation Risk ◽  
Body Mass ◽  
Field Experiments ◽  
Empirical Studies ◽  
The Body ◽  
Training Procedure ◽  
Predator Prey ◽  
Ecological Experiments ◽  
Barn Owls ◽  
Rodent Prey

Predators affect prey directly by predation and indirectly by triggering behavioral responses that aim at reducing predation risk. In this paper, I present a method for training an avian predator which can allow separating between its direct and indirect effects on prey in various experimental setups. Barn owls are found to be a valuable tool for empirically testing different hypotheses related to predator-prey interactions, population dynamics, and inter-specific competition, all performed in the field using authentic rodent prey and their natural predators. Barn owls are raised and trained to participate in field experiments using classical conditioning, and are trained either to catch rodents or only to fly above a certain area without making any attempt to attack the prey, simulating solely predation risk. Body mass is a crucial factor in the training procedure, and I thus define five body mass ranges that characterize different behavioral stages in the training of owls. A logistic model is used to calculate and to predict changes in the body mass during the growth and training periods of owls. Finally, I discuss several possible implications of the usage of trained barn owls in empirical studies.

scholarly journals Species interactions and spatial heterogeneity: predicting cascading predator effects on landscape biogeochemistry

2020 ◽  
Author(s):  
Julia D. Monk ◽  
A. Carla Staver ◽  
Oswald J. Schmitz
Keyword(s):  
Spatial Heterogeneity ◽  
Predation Risk ◽  
Species Interactions ◽  
Animal Movement ◽  
Landscape Heterogeneity ◽  
Ecological Systems ◽  
General Will ◽  
Positive Feedbacks ◽  
Predator Prey ◽  
Risk Effects

Spatial heterogeneity in ecological systems can result from top-down processes, but despite some theoretical attention, the emergence of spatial heterogeneity from feedbacks with consumers is not well understood empirically. Interactions between predators and prey influence animal movement and associated nutrient transport and release, generating spatial heterogeneity that cascades throughout ecological systems. In this review, we synthesize the existing literature to evaluate the mechanisms by which terrestrial predators can generate spatial heterogeneity in biogeochemical processes through consumptive and non-consumptive effects. Overall, we propose that predators increase heterogeneity in ecosystems whenever predation is intense and spatially variable, whereas predator-prey interactions homogenize ecosystems whenever predation is weak or diffuse in space. This leads to several testable hypotheses: (1) that predation and carcass deposition at high-predation risk sites stimulate positive feedbacks between predation risk and nutrient availability; (2) that prey generate nutrient hotspots when they concentrate activity in safe habitats, but instead generate nutrient subsidies when they migrate daily between safe and risky habitats; (3) that herbivore body size mediates risk effects, such that megaherbivores are more likely to homogenize ecosystems; and 4) that predator loss in general will tend to homogenize ecosystems. Testing these hypotheses will advance our understanding of whether predators amplify landscape heterogeneity in ecological systems.

scholarly journals Using 3D micro-geomorphometry to quantify interstitial spaces of an oyster cluster

2019 ◽  
Author(s):  
Kwanmok Kim ◽  
Vincent Lecours ◽  
Peter C. Frederick
Keyword(s):  
Species Interactions ◽  
Point Cloud ◽  
Structural Complexity ◽  
Ecological Studies ◽  
Empirical Relationships ◽  
Predator Prey ◽  
Interstitial Volume ◽  
Curvature Measures ◽  
Technological Limitations

In ecology, it is assumed that the characteristics (e.g. shape, size) of interstitial spaces found in a variety of habitats affect the colonization of species, species interactions, and species composition. However, those characteristics have traditionally been difficult to measure due to technological limitations. In this study, we used the Structure-from-Motion (SfM) photogrammetry technique to measure the physical characteristics of interstitial spaces in a small oyster cluster. The point cloud (and mesh) of the oyster cluster derived from SfM photogrammetry was found to be accurate enough (mean error of 0.654 mm) to conduct 3D geomorphometric analyses. We present an example of measures of curvature, roughness, interstitial volume, surface area, and openness for three 3D interstitial spaces. The interpretation of those measures enabled establishing which interstitial spaces were the most likely to be used as a shelter for an average crab. Those spaces are characterized by smaller openness and higher roughness and curvature measures. This initial quantitative 3D characterization of an oyster cluster is the first step in establishing empirical relationships between structural complexity of biological structures like oyster clusters and their ecological role for instance in predator-prey interactions. Overall, this study demonstrates the feasibility of combining SfM photogrammetry with geomorphometry for fine-scale ecological studies.

scholarly journals Topographic Effects on the Spatial Species Associations in Diverse Heterogeneous Tropical Evergreen Forests

2021 ◽  
Vol 13 (5) ◽  
pp. 2468
Author(s):  
Nguyen Hong Hai ◽  
Yousef Erfanifard ◽  
Van Bac Bui ◽  
Trinh Hien Mai ◽  
Any Mary Petritan ◽  
...  
Keyword(s):  
Species Interactions ◽  
Species Coexistence ◽  
Spatial Scales ◽  
Interspecific Interactions ◽  
Spatial Association ◽  
Topographic Effects ◽  
Habitat Association ◽  
Important Species ◽  
Evergreen Forests ◽  
Partial Overlap

Studying spatial patterns and habitat association of plant communities may provide understanding of the ecological mechanisms and processes that maintain species coexistence. To conduct assessments of correlation between community compositions and habitat association, we used data from two topographically different plots with 2 ha area in tropical evergreen forests with the variables recorded via grid systems of 10 × 10 m subplots in Northern-Central Vietnam. First, we tested the relationship between community composition and species diversity indices considering the topographical variables. We then assessed the interspecific interactions of 20 dominant plant species using the nearest-neighbor distribution function, Dij(r), and Ripley’s K-function, Kij(r). Based on the significant spatial association of species pairs, indices of interspecific interaction were calculated by the quantitative amounts of the summary statistics. The results showed that (i) community compositions were significantly influenced by the topographic variables and (ii) almost 50% significant pairs of species interactions were increased with increasing spatial scales up to 10–15 m, then declined and disappeared at scales of 30–40 m. Segregation and partial overlap were the dominant association types and disappeared at larger spatial scales. Spatial segregation, mixing, and partial overlap revealed the important species interactions in maintaining species coexistence under habitat heterogeneity in diverse forest communities.

Do changes in reef habitats influence relative predation risk on the juvenile Australasian spiny lobster, Jasus edwardsii (Hutton, 1875)?

Crustaceana ◽  
2015 ◽  
Vol 88 (7-8) ◽  
pp. 839-856 ◽  
Author(s):  
J. Hesse ◽  
J. A. Stanley ◽  
A. G. Jeffs
Keyword(s):  
Predation Risk ◽  
Spatial Scales ◽  
Spiny Lobster ◽  
Habitat Type ◽  
Small Spatial Scale ◽  
Important Species ◽  
Early Juvenile ◽  
Risk Of Predation ◽  
Jasus Edwardsii ◽  
Commercially Important

Kelp habitats are in decline in many temperate coastal regions of the world due to climate change and expansion of populations of grazing urchins. The loss of kelp habitat may influence the vulnerability to predators of the juveniles of commercially important species. In this study relative predation rates for kelp versus barren reef habitat were measured for early juvenile Australasian spiny lobster, Jasus edwardsii (Hutton, 1875), on the northeastern coast of New Zealand using tethering methods. Variation in assemblages of predators over small spatial scales appeared to be more important for determining the relative predation of lobsters, regardless of habitat type. Therefore, the assessment of relative predation risk to early juvenile lobsters between kelp and barren habitats will require more extensive sampling at a small spatial scale, as well as a specific focus on sampling during crepuscular and nocturnal periods when these lobsters are most at risk of predation.

scholarly journals Long-term UVB exposure promotes predator-inspection behaviour in a fish

2017 ◽  
Vol 13 (12) ◽  
pp. 20170497 ◽  
Author(s):  
Simon Vitt ◽  
Janina E. Zierul ◽  
Theo C. M. Bakker ◽  
Ingolf P. Rick
Keyword(s):  
Gasterosteus Aculeatus ◽  
Stratospheric Ozone ◽  
Ultraviolet B ◽  
Antipredator Behaviour ◽  
Uvb Radiation ◽  
Ecological Processes ◽  
Predator Prey ◽  
Natural Sunlight ◽  
Predator Inspection

Ultraviolet-B radiation (UVB) reaching the earth's surface has increased due to human-caused stratospheric ozone depletion. Whereas the harmful effects of UVB on aquatic organisms are well studied at the molecular and cellular level, recent studies have also begun to address behavioural changes caused by sublethal amounts of UVB. However, the behavioural consequences of long-term exposure to ecologically relevant UVB levels over several life stages are virtually unknown, particularly with regard to predator–prey behaviour. We found increased predator-inspection behaviour together with a smaller body length in three-spined sticklebacks ( Gasterosteus aculeatus ) after fish were exposed for about seven months to natural sunlight conditions with enhanced UVB, compared with full siblings exposed to natural sunlight only. The observed change in antipredator behaviour may reflect a direct behavioural response mediated through UVB-induced oxidative stress during development. Alternatively, the smaller body size in UVB-exposed fish may result in an increased inspection effort allowing them to spend more time foraging. Our findings suggest that, within the scope of environmental change, UVB radiation constitutes an important stress factor by eliciting behavioural responses that influence crucial ecological processes, such as predator–prey interactions.

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