scholarly journals Relying on known or exploring for new? Movement patterns and reproductive resource use in a tadpole-transporting frog

PeerJ ◽  
2017 ◽  
Vol 5 ◽  
pp. e3745 ◽  
Author(s):  
Kristina B. Beck ◽  
Matthias-Claudio Loretto ◽  
Max Ringler ◽  
Walter Hödl ◽  
Andrius Pašukonis
Keyword(s):  
Spatial Memory ◽  
Resource Use ◽  
Resource Availability ◽  
Movement Patterns ◽  
Poison Frogs ◽  
Fluctuating Resources ◽  
Allobates Femoralis ◽  
First Time ◽  
Tadpole Transport ◽  
Home Territory

Animals relying on uncertain, ephemeral and patchy resources have to regularly update their information about profitable sites. For many tropical amphibians, widespread, scattered breeding pools constitute such fluctuating resources. Among tropical amphibians, poison frogs (Dendrobatidae) exhibit some of the most complex spatial and parental behaviors—including territoriality and tadpole transport from terrestrial clutches to ephemeral aquatic deposition sites. Recent studies have revealed that poison frogs rely on spatial memory to successfully navigate through their environment. This raises the question of when and how these frogs gain information about the area and suitable reproductive resources. To investigate the spatial patterns of pool use and to reveal potential explorative behavior, we used telemetry to follow males of the territorial dendrobatid frog Allobates femoralis during tadpole transport and subsequent homing. To elicit exploration, we reduced resource availability experimentally by simulating desiccated deposition sites. We found that tadpole transport is strongly directed towards known deposition sites and that frogs take similar direct paths when returning to their home territory. Frogs move faster during tadpole transport than when homing after the deposition, which probably reflects different risks and costs during these two movement phases. We found no evidence for exploration, neither during transport nor homing, and independent of the availability of deposition sites. We suggest that prospecting during tadpole transport is too risky for the transported offspring as well as for the transporting male. Relying on spatial memory of multiple previously discovered pools appears to be the predominant and successful strategy for the exploitation of reproductive resources in A. femoralis. Our study provides for the first time a detailed description of poison frog movement patterns during tadpole transport and corroborates recent findings on the significance of spatial memory in poison frogs. When these frogs explore and discover new reproductive resources remains unknown.

Indicators of Land Degradation Vulnerability due to Anthropic Factors

2013 ◽  
pp. 1400-1413 ◽  
Author(s):  
V. Imbrenda ◽  
M. D’Emilio ◽  
M. Lanfredi ◽  
M. Ragosta ◽  
T. Simoniello
Keyword(s):  
Land Management ◽  
Land Degradation ◽  
Resource Availability ◽  
Census Data ◽  
Vulnerability Index ◽  
Decision Makers ◽  
Accurate Estimation ◽  
Spatial Characterization ◽  
Land Cover Data ◽  
First Time

Land degradation is one of the most impacting phenomena on natural resource availability, both in quantitative and qualitative terms. In order to provide efficient tools for territorial sustainable management in areas affected by land degradation, it is important to define suitable models and indicators able to identify exposed areas and their vulnerability level, so as to provide an effective support for decision makers in identifying intervention priorities and planning mitigation/adaptation strategies. This work is focused on the evaluation at high spatial detail of land degradation vulnerability due to anthropic factors, which is a crucial issue in areas devoted to farming practices. Vulnerability is evaluated by integrating a new indicator of the mechanization level the authors recently developed, with a set of census based indicators of land management. The new indicator is independent of census data being based on land cover data; thus, it can provide a better spatial characterization and a more frequent updating compared to commonly adopted indices that are evaluated at municipal scale. By analyzing data for the whole Southern Italy, such an indicator was integrated for the first time at full spatial resolution to obtain a final vulnerability index of land management. This comprehensive index enabled a more accurate estimation of the land degradation vulnerability due to anthropic factors allowing the discrimination of priority areas within the municipal areas.

Indicators of Land Degradation Vulnerability Due to Anthropic Factors

2013 ◽  
pp. 87-101 ◽  
Author(s):  
V. Imbrenda ◽  
M. D’Emilio ◽  
M. Lanfredi ◽  
M. Ragosta ◽  
T. Simoniello
Keyword(s):  
Land Management ◽  
Land Degradation ◽  
Resource Availability ◽  
Census Data ◽  
Vulnerability Index ◽  
Decision Makers ◽  
Accurate Estimation ◽  
Spatial Characterization ◽  
Land Cover Data ◽  
First Time

Land degradation is one of the most impacting phenomena on natural resource availability, both in quantitative and qualitative terms. In order to provide efficient tools for territorial sustainable management in areas affected by land degradation, it is important to define suitable models and indicators able to identify exposed areas and their vulnerability level, so as to provide an effective support for decision makers in identifying intervention priorities and planning mitigation/adaptation strategies. This work is focused on the evaluation at high spatial detail of land degradation vulnerability due to anthropic factors, which is a crucial issue in areas devoted to farming practices. Vulnerability is evaluated by integrating a new indicator of the mechanization level the authors recently developed, with a set of census based indicators of land management. The new indicator is independent of census data being based on land cover data; thus, it can provide a better spatial characterization and a more frequent updating compared to commonly adopted indices that are evaluated at municipal scale. By analyzing data for the whole Southern Italy, such an indicator was integrated for the first time at full spatial resolution to obtain a final vulnerability index of land management. This comprehensive index enabled a more accurate estimation of the land degradation vulnerability due to anthropic factors allowing the discrimination of priority areas within the municipal areas.

scholarly journals Leaf-level resource use for evergreen and deciduous conifers along a resource availability gradient

2000 ◽  
Vol 14 (3) ◽  
pp. 281-292 ◽  
Author(s):  
B. D. Kloeppel ◽  
S. T. Gower ◽  
J. G. Vogel ◽  
P. B. Reich
Keyword(s):  
Resource Use ◽  
Resource Availability ◽  
Leaf Level

scholarly journals Do city cachers store less? The effect of urbanization and exploration on spatial memory in individual scatter hoarders

2018 ◽  
Author(s):  
Megan Joy Thompson ◽  
Julie Morand-Ferron
Keyword(s):  
Spatial Memory ◽  
Spatial Task ◽  
Food Sources ◽  
Urban Gradient ◽  
Supplemental Food ◽  
Rural Environments ◽  
Bird Feeders ◽  
The Individual ◽  
Speed Accuracy ◽  
First Time

Urbanization has been shown to affect a variety of traits in animals, including their physiology, morphology, and behaviour, but it is less clear how cognitive traits are modified. Urban habitats contain artificially elevated food sources, such as bird feeders, that are known to affect the foraging behaviours of urban animals. As of yet however, it is not known whether urbanization and the abundance of supplemental food during the winter reduce caching behaviours and spatial memory in scatter hoarders. We aimed to examine individual variation in caching and spatial memory between and within urban and rural habitats to determine i) whether urban individuals cache less frequently and perform less accurately on a spatial task, and ii) explore, for the first time in scatter hoarders, whether slower explorers perform more accurately on a spatial task, indicating a speed-accuracy trade-off within individuals. We assessed spatial memory of wild-caught black-capped chickadees (Poecile atricapillus; N = 96) from 14 sites along an urban gradient. While the individuals that cached more food in captivity were all from rural environments, we find no clear evidence that caching intensity and spatial memory accuracy differ along an urban gradient, and find no significant relationship between spatial cognition and exploration of a novel environment within individuals. However, individuals that performed more accurately also tended to cache more frequently, suggesting for the first time that the specialization of spatial memory in scatter hoarders may also occur at the level of the individual in addition to the population and species levels.

scholarly journals Spatio-Temporal Characteristics of the Prolonged Courtship in Brilliant-Thighed Poison Frogs, Allobates femoralis

Herpetologica ◽  
2019 ◽  
Vol 75 (4) ◽  
pp. 268 ◽  
Author(s):  
Susanne Stückler ◽  
Max Ringler ◽  
Andrius Pašukonis ◽  
Steffen Weinlein ◽  
Walter Hödl ◽  
...  
Keyword(s):  
Temporal Characteristics ◽  
Poison Frogs ◽  
Allobates Femoralis ◽  
Spatio Temporal

Resource use and defence by ruby-throated hummingbirds during stopover

Behaviour ◽  
2019 ◽  
Vol 156 (2) ◽  
pp. 131-153
Author(s):  
Theodore J. Zenzal ◽  
Frank R. Moore
Keyword(s):  
Resource Use ◽  
Resource Availability ◽  
Migratory Birds ◽  
Fuel Load ◽  
Resource Quality ◽  
Access To Resources ◽  
Stopover Duration ◽  
Resource Defence ◽  
Conspecific Density

Abstract Many migrants must forage en route when fuel reserves are depleted and access to resources can be influenced by a variety of factors, including the sex, age, and current fuel stores of individuals, as well as resource availability. The objective of this study is to determine the factors that influence the use and defence of resources by migrating ruby-throated hummingbirds (Archilochus colubris). Our results illustrate that resource use: (1) is dependent on sex and resource defence, (2) decreases with fuel load and (3) increases with stopover duration as well as the number of unique feeders visited. Resource defence is closely tied to (1) competition, with the greatest conspecific density resulting in focal individuals being chased from feeders and (2) the interplay between resource quality and fuel load. Our research enhances our understanding of strategies migratory birds use to acquire and defend resources during stopover.

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