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Your search keyword '"Jesús D. Nuñez"' showing total 2 results
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2 results on '"Jesús D. Nuñez"'

1. Automated tracking of aquatic crustaceans with potential application on the quantification of animals movement

Author

Jesús D. Nuñez, Octavio Massone, and José A. García

Subjects
Python, OpenCV, object detection, video tracking, behavioural ecology, Environmental sciences, GE1-350, Ecology, QH540-549.5
Abstract

Here, we present a set of algorithms using the Python programming language, that will allow using a routine for object detection and tracking in experimental videos. We developed a script, under the fundamentals of background subtraction and image thresholding (using the OpenCV package), that makes it possible to track a wide spectrum of animals under different conditions. We have validated this script through testing on semi-terrestrial and aquatic crustacean species and under different experimental scenarios (laboratory and field sampling and using video created under nocturnal and diurnal conditions). The open-source nature of the script allows for flexibility and scalability, so it can be easily customized and is thus transferable to other species/experiments in the context of behavioral ecology. The tracking script is easy customizable and free alternative to commercial video tracking systems and therefore, applicable to a wide variety of both educational and research programs.

Published
2022
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2. Artificial light at night (ALAN) mediates transient spatial aggregation of an ecosystem engineer, the crab Neohelice granulata (Dana, 1851) (Decapoda: Brachyura: Varunidae), under different ecological contexts

Author

Tomas Atilio Luppi, Nicolás Mariano Chiaradia, Jesús D. Quiñones-Llópiz, Pablo D. Ribeiro, and Jesús D Nuñez

Subjects
biology, Artificial light, Ecology, Decapoda, Varunidae, Spatial aggregation, Aquatic Science, biology.organism_classification, Neohelice, Ecosystem engineer
Abstract

Artificial light at night (ALAN) alters natural light regimes in much of the world. The effect of ALAN has been studied in several organisms, although not so much in crustaceans, especially in adult stages. We evaluated the relationship between different intensities of ALAN and the abundance of burrows, and surface activity of the crab Neohelice granulata (Dana, 1851). The study was conducted in 2016 and 2017, in two salt marshes, San Antonio Oeste and Mar Chiquita, Argentina, both having different ecological contexts. During new-moon nights we counted the number of burrows and crabs on the surface and along a gradient of artificial light caused by street lighting with high-pressure sodium lamps. We found that the number of crabs on the surface increased with light intensity and that crabs were almost exclusively males. In contrast, we found that the number of burrows was not related to light intensity, suggesting that the increase of crabs on the surface was mainly due to an increase in their activity. We considered two main mechanisms causing the increase on surface activity of crabs: 1) an increase in the frequency of emergence and short-distance excursions around their burrow and 2) an increase of mobility with long-distance directional displacement from dark to lit areas. Overall, our observations suggest that the presence of ALAN can modify individual crab behavior (i.e., aggregation) and consequently effects on ecosystem functioning.

Published
2021

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