Behavioral interactions are modulated by facilitation along a heterotrophic succession

Naves‐Alegre, Lara; Sebastián‐González, Esther; Sánchez‐Zapata, José Antonio

doi:10.1002/ecy.4236

Cited by 5 publications

(1 citation statement)

References 61 publications

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“…It is essential to model nonindependent visit timings when resources can be used multiple times. Consider larger carcasses, for instance, where the initial use by large carnivores enables smaller species to subsequently use them (Naves‐Alegre et al., 2024 ). Conversely, large species can directly (i.e.…”

Section: Discussionmentioning

confidence: 99%

A statistical approach to assess interspecific consumptive competition and functional redundancy in ephemeral resource uses using camera traps

Nakashima,

Hashizume,

Kanda

2024

Ecology and Evolution

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Camera traps have been widely used in wildlife research, offering significant potential for monitoring species interactions at ephemeral resources. However, raw data obtained from camera traps often face limitations due to observation censoring, where resource consumption by dominant animals may obscure potential resource use by less dominant animals. We extended time‐to‐detection occupancy modeling to quantify interspecific consumptive competition and redundancy of ecosystem functions through consumption between two species, while accounting for observation censoring. By treating resource use by rival species as censored data, we estimated the proportion of resources potentially used in the absence of rival species and calculated the loss caused by the rival species, which is defined as “Competition Intensity Index.” We also defined the Unique Functional Contribution, which represents the net functional loss when a species is removed, calculated by excluding the contribution potentially substituted by the other species. We also considered resource degradation and computed the quantity of resources acquired by each species. This established framework was applied to predation data on bird nests by alien squirrels and other predators (Case 1) as well as scavenging on mammalian carcasses by two carnivores (Case 2). In Case 1, the introduction of squirrels significantly affected the breeding success of birds. Although nests were being preyed upon by native crows also, our model estimated that Unique Functional Contribution by the squirrels was 0.47. This means that, by eradicating the squirrels, the reproductive success of the birds could potentially increase by as much as 47%. In Case 2, the Competition Intensity Index for foxes was 0.17, whereas that for raccoon dogs was 0.46, suggesting an asymmetric effect of resource competition between the two species. The frequency distribution of wet mass available to the two species differed significantly. This approach will enable a more robust construction of resource–consumer interaction networks.

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Section: Discussionmentioning

confidence: 99%

A statistical approach to assess interspecific consumptive competition and functional redundancy in ephemeral resource uses using camera traps

Nakashima,

Hashizume,

Kanda

2024

Ecology and Evolution

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Behavioral interactions are modulated by facilitation along a heterotrophic succession

Naves‐Alegre,

Sebastián‐González,

Sánchez‐Zapata

2024

Ecology

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Competition and facilitation drive ecological succession but are often hard to quantify. In this sense, behavioral data may be a key tool to analyze interaction networks, providing insights into temporal trends in facilitation and competition processes within animal heterotrophic succession. Here, we perform the first in‐depth analysis of the factors driving temporal dynamics of carcass consumption by analyzing behavioral patterns (i.e., interactions) and community dynamics metrics (i.e., species richness, abundance, turnover, and diversity) in a Neotropical scavenger guild. For this purpose, we monitored goat carcasses using automatic cameras. From 573 reviewed videos, we registered 1784 intraspecific and 624 interspecific interactions, using intraspecific and interspecific aggressions (n = 2048) as a behavioral proxy of competition intensity. Our results show that resource availability shapes behavioral interactions between vultures, with a specific effect of the different species on behavioral and competition dynamics, showing the existence of a hierarchy between species. Furthermore, behavioral processes linked to carcass opening tended to be facilitative, related to moments of higher tolerance (i.e., lower aggressiveness), thus reducing competition intensity and also affecting community structure and dynamics. This novel framework demonstrates complex ephemeral successional processes characterized by a fluctuation in facilitation and competition intensity during the consumption of an unpredictable resource linked to key ecosystem processes.

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Predicted short‐term mesoscavenger release gives way to apex‐scavenger dominance

Donohue,

Piiroinen,

Kane

2024

Journal of Animal Ecology

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Vultures play a crucial role in scavenging communities as apex scavengers. Scavenging communities in turn are a key component of terrestrial ecosystems, ensuring that dead biomass is removed quickly and efficiently. Anthropogenic disturbances, particularly mass poisonings, have caused crashes in vulture populations in Africa and Asia. We ask if vultures can re‐establish themselves in a scavenging community from a point of near extirpation. To allow for maximum knowledge transfer across ecosystems, we focus on an ecosystem that is otherwise considered pristine. We chose Kruger National Park (KNP), a well‐documented African scavenging community, as our focal ecosystem and parameterised a mathematical model of scavenging‐community dynamics using field data from the park. We predicted the upper limit of vulture population size in an ecosystem like KNP. We then analysed vultures' path to recovery, using this empirically parameterised scavenging‐community model. We used perturbation methods to determine how parameter values that may be specific to KNP influence our predictions. Comparisons of predicted vulture carrying capacity with recent population estimates suggest that the cumulative effect of human activities on vulture abundance is larger than previously believed. Our analysis shows that vulture populations can reach their carrying capacity approximately five decades after a poisoning event that would almost extirpate the population. Over shorter time scales, we predict a decade of enhanced mammal abundance (i.e. mesoscavenger release) before the mammals are excluded from the scavenging community. In our study system, jackals and hyenas are the mammalian groups predicted to benefit from the absence of vultures. However, neither group removes biomass as efficiently as vultures and animal carcasses are predicted to accumulate in the ecosystem while the vulture population recovers. In our framework, the carrying capacity for vulture populations is determined by carcass availability. As evidence for an alternative regulating factor is lacking, we conclude that present‐day vulture population densities are orders of magnitude below their upper limits. Our results therefore suggest that with a recovery plan in place, the long‐term prospects for vulture species and the associated ecosystems are positive.

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Behavioral interactions are modulated by facilitation along a heterotrophic succession

Cited by 5 publications

References 61 publications

A statistical approach to assess interspecific consumptive competition and functional redundancy in ephemeral resource uses using camera traps

A statistical approach to assess interspecific consumptive competition and functional redundancy in ephemeral resource uses using camera traps

Behavioral interactions are modulated by facilitation along a heterotrophic succession

Predicted short‐term mesoscavenger release gives way to apex‐scavenger dominance

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