Optimizing sampling design to deal with mist-net avoidance in Amazonian birds and bats.

Mist netting is a widely used technique to sample bird and bat assemblages. However, captures often decline with time because animals learn and avoid the locations of nets. This avoidance or net shyness can substantially decrease sampling efficiency. We quantified the day-to-day decline in captures...

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Main Authors: João Tiago Marques, Maria J Ramos Pereira, Tiago A Marques, Carlos David Santos, Joana Santana, Pedro Beja, Jorge M Palmeirim
Format: Article
Language:English
Published: Public Library of Science (PLoS) 2013-01-01
Series:PLoS ONE
Online Access:http://europepmc.org/articles/PMC3776857?pdf=render
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author João Tiago Marques
Maria J Ramos Pereira
Tiago A Marques
Carlos David Santos
Joana Santana
Pedro Beja
Jorge M Palmeirim
author_facet João Tiago Marques
Maria J Ramos Pereira
Tiago A Marques
Carlos David Santos
Joana Santana
Pedro Beja
Jorge M Palmeirim
author_sort João Tiago Marques
collection DOAJ
description Mist netting is a widely used technique to sample bird and bat assemblages. However, captures often decline with time because animals learn and avoid the locations of nets. This avoidance or net shyness can substantially decrease sampling efficiency. We quantified the day-to-day decline in captures of Amazonian birds and bats with mist nets set at the same location for four consecutive days. We also evaluated how net avoidance influences the efficiency of surveys under different logistic scenarios using re-sampling techniques. Net avoidance caused substantial declines in bird and bat captures, although more accentuated in the latter. Most of the decline occurred between the first and second days of netting: 28% in birds and 47% in bats. Captures of commoner species were more affected. The numbers of species detected also declined. Moving nets daily to minimize the avoidance effect increased captures by 30% in birds and 70% in bats. However, moving the location of nets may cause a reduction in netting time and captures. When moving the nets caused the loss of one netting day it was no longer advantageous to move the nets frequently. In bird surveys that could even decrease the number of individuals captured and species detected. Net avoidance can greatly affect sampling efficiency but adjustments in survey design can minimize this. Whenever nets can be moved without losing netting time and the objective is to capture many individuals, they should be moved daily. If the main objective is to survey species present then nets should still be moved for bats, but not for birds. However, if relocating nets causes a significant loss of netting time, moving them to reduce effects of shyness will not improve sampling efficiency in either group. Overall, our findings can improve the design of mist netting sampling strategies in other tropical areas.
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spelling doaj.art-01bda9ab9bfc4e1b9909f2dab49a14f52022-12-21T19:58:04ZengPublic Library of Science (PLoS)PLoS ONE1932-62032013-01-0189e7450510.1371/journal.pone.0074505Optimizing sampling design to deal with mist-net avoidance in Amazonian birds and bats.João Tiago MarquesMaria J Ramos PereiraTiago A MarquesCarlos David SantosJoana SantanaPedro BejaJorge M PalmeirimMist netting is a widely used technique to sample bird and bat assemblages. However, captures often decline with time because animals learn and avoid the locations of nets. This avoidance or net shyness can substantially decrease sampling efficiency. We quantified the day-to-day decline in captures of Amazonian birds and bats with mist nets set at the same location for four consecutive days. We also evaluated how net avoidance influences the efficiency of surveys under different logistic scenarios using re-sampling techniques. Net avoidance caused substantial declines in bird and bat captures, although more accentuated in the latter. Most of the decline occurred between the first and second days of netting: 28% in birds and 47% in bats. Captures of commoner species were more affected. The numbers of species detected also declined. Moving nets daily to minimize the avoidance effect increased captures by 30% in birds and 70% in bats. However, moving the location of nets may cause a reduction in netting time and captures. When moving the nets caused the loss of one netting day it was no longer advantageous to move the nets frequently. In bird surveys that could even decrease the number of individuals captured and species detected. Net avoidance can greatly affect sampling efficiency but adjustments in survey design can minimize this. Whenever nets can be moved without losing netting time and the objective is to capture many individuals, they should be moved daily. If the main objective is to survey species present then nets should still be moved for bats, but not for birds. However, if relocating nets causes a significant loss of netting time, moving them to reduce effects of shyness will not improve sampling efficiency in either group. Overall, our findings can improve the design of mist netting sampling strategies in other tropical areas.http://europepmc.org/articles/PMC3776857?pdf=render
spellingShingle João Tiago Marques
Maria J Ramos Pereira
Tiago A Marques
Carlos David Santos
Joana Santana
Pedro Beja
Jorge M Palmeirim
Optimizing sampling design to deal with mist-net avoidance in Amazonian birds and bats.
PLoS ONE
title Optimizing sampling design to deal with mist-net avoidance in Amazonian birds and bats.
title_full Optimizing sampling design to deal with mist-net avoidance in Amazonian birds and bats.
title_fullStr Optimizing sampling design to deal with mist-net avoidance in Amazonian birds and bats.
title_full_unstemmed Optimizing sampling design to deal with mist-net avoidance in Amazonian birds and bats.
title_short Optimizing sampling design to deal with mist-net avoidance in Amazonian birds and bats.
title_sort optimizing sampling design to deal with mist net avoidance in amazonian birds and bats
url http://europepmc.org/articles/PMC3776857?pdf=render
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