Increasing number of point counts influences estimates of bird and anuran species richness at the wetland scale

Abstract The Conde municipality is located in the northern coast of the state of Bahia (NC), northeastern Brazil, and is part of the Atlantic Tropical domain. The anuran fauna of the northern portion of the NC is still poorly known if compared to the southern portion. The Restinga is one of the predominant environments of the coastal plains of the NC and it is characterized essentially by presenting sandy soil covered by herbaceous and shrubby vegetation. The objective of this study was to determine the anuran species composition and diversity for the Restinga of the Conde municipality. Sampling was carried out at night by active search over four periods of five consecutive days each, two over the 'main rainy season' and two in a 'lesser rainy season', using 14 sample units (SUs) and five extra sample plots (EPs). We calculated dominance and species diversity using the Berger-Parker and Shannon-Wiener H' indices, respectively. We used accumulation curves and the Jackknife 1 estimator to estimate anuran species richness, considering only the data obtained from the SUs. We recorded 713 anuran specimens distributed within 33 species, 13 genera and five families (Bufonidae, Craugastoridae, Hylidae, Leptodactylidae and Microhylidae). The Hylidae and Leptodactylidae families had the highest species richness. Considering only the SUs (Jackknife 1 estimator in brackets), we recorded 28 species in the study area (33.9 ± 2.3), 13 in Shrubby Vegetation Zones - SVZ (20.8 ± 2.9) and 25 in Freshwater Wetland Zones - FWZ (28.9 ± 1.9). The abundance and species diversity of the FWZ (n = 638 specimens; H'= 2.4) were higher than those recorded for the SVZ (n = 52 specimens; H' = 1.9). The SVZ and FWZ showed distinct dominant species, wherein Pristimantis paulodutrai was the dominant species in SVZ and Scinax fuscomarginatus in FWZ. The Restinga of the Conde municipality stands out as the one with the highest anuran species richness already recorded considering only SVZ and FWZ. Moreover, its anuran species composition represented 55% of the anuran species known for the NC and included taxa common to three different morphoclimatic domains (Tropical Atlantic, Cerrado and Caatinga).

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Overlap in avian communities produces unimodal richness peaks on Bornean mountains

Journal of Tropical Ecology ◽

10.1017/s0266467418000081 ◽

2018 ◽

Vol 34 (2) ◽

pp. 75-92 ◽

Cited By ~ 2

Author(s):

Ryan C. Burner ◽

Alison R. Styring ◽

Chandradewana Boer ◽

Frederick H. Sheldon

Keyword(s):

Species Richness ◽

Bird Species ◽

Sufficient Evidence ◽

Altitudinal Distribution ◽

Bird Species Richness ◽

Point Counts ◽

Habitat Gradient ◽

Quantitative Analyses ◽

Meta Analyses ◽

Replicated Systems

Abstract:Altitudinal gradients provide tractable, replicated systems in which to study changes in species richness and community composition over relatively short distances. Previously, richness was often assumed to follow a monotonic decline with altitude, but recent meta-analyses show that more complex patterns, including mid-altitude richness peaks, are also prevalent in birds. In this study, we used point counts to survey birds at multiple altitudes on three mountains on the island of Borneo in Sundaland, an area for which quantitative analyses of avian altitudinal distribution are unavailable. In total we conducted 1088 point counts and collected associated habitat data at 527 locations to estimate species richness by altitude on Mt Mulu (2376 m), Mt Pueh (1550 m) and Mt Topap Oso (1450 m). On Mulu, the only mountain with an intact habitat gradient, bird species richness peaks at 600 m. Richness appeared to peak at 600 m on Totap Oso as well, but on Pueh it peaked several hundred metres higher. The richness peak on Mulu differs from that predicted by null models and is instead caused by the overlap of distinct lowland and montane avifaunas, supporting the faunal overlap hypothesis. This finding provides further evidence that a lack of coincidence between peak turnover and peak richness is not sufficient evidence to rule out faunal overlap as a causal factor.

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Influence of Land-Use Type on Forest Bird Community Composition in Mount Kenya Forest

International Journal of Ecology ◽

10.1155/2019/8248270 ◽

2019 ◽

Vol 2019 ◽

pp. 1-8 ◽

Cited By ~ 1

Author(s):

Samuel N. Mahiga ◽

Paul Webala ◽

Mugo J. Mware ◽

Paul K. Ndang’ang’a

Keyword(s):

Land Use ◽

Species Richness ◽

Bird Community ◽

Natural Forest ◽

Forest Biodiversity ◽

Natural Forests ◽

Plantation Forest ◽

Point Counts ◽

Plantation Forests ◽

Relative Species Richness

Few studies have explored how human land uses influence and support persistence of forest biodiversity in central Kenya. In the case of the Mount Kenya ecosystem, farmlands and plantation forests are significant land-use types. Using point counts, we assessed bird communities in natural forests, plantation forests, and farmlands in the Nanyuki Forest Block, Western Mount Kenya. Bird point counts were undertaken during two sampling periods (wet and dry season). Compared to farmlands and plantation forest, natural forest had the highest overall avian species richness and relative species richness of all except one forest-dependent foraging guild (granivores) and nonforest species, which occurred frequently only on farmlands. Plantation forest had the lowest relative richness of all avian habitat and foraging guilds. Conversely, specialist forest-dependent species mainly occurred in the structurally complex remnant natural forest. Our study underscores the importance of remnant natural forests for the persistence and conservation of forest biodiversity and risks posed by replacing them with plantation forests and farmlands.

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Powerline easements through forests: a case study of impacts on avifauna

Pacific Conservation Biology ◽

10.1071/pc980079 ◽

1998 ◽

Vol 4 (1) ◽

pp. 79 ◽

Cited By ~ 10

Author(s):

Jack Baker ◽

Ross L. Goldingay ◽

Robert J. Whelan

Keyword(s):

Species Richness ◽

Bird Community ◽

Forest Habitat ◽

Bird Abundance ◽

Point Counts ◽

Southeastern Australia ◽

Total Species Richness ◽

New Type ◽

Forest Values

Powerline easements are typically a strip cleared of trees and tall vegetation to a width of approximately 50 m. They may affect avifauna by modification and fragmentation of forest habitat. We investigated the responses of the bird community to easements at three sites in southeastern Australia using 25 m radius point-counts spaced at 50 m intervals from the easement to 300 m inside the forest. The easements caused an absolute loss of habitat for forest avifauna, with abundance and species richness at the easement less than 20% of the forest values. Four species of easement opportunist and one easement specialist provided evidence that the easement represented a new type of habitat for avifauna. A barrier effect of fragmentation may occur for four species of easement avoiders. These were small to medium-sized terrestrial birds associated with dense ground and/or understorey cover. The edge effect of fragmentation was an adverse impact on forest avifauna. At the margin (25?125 m from the easement) of the forest, bird abundance, mean species richness and total species richness were significantly less than the corresponding values for the interior (225?325 m) of the forest. The mean abundance at the sites varied from 13.0?17.7 birds/ha and the species richness varied significantly among sites. The adverse impacts of powerline easements on native avifauna could be minimized by site-specific management which includes strategies to minimize the loss of forest habitat and to ameliorate the effects of fragmentation.

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Diversity and associations between coastal habitats and anurans in southernmost Brazil

Anais da Academia Brasileira de Ciências ◽

10.1590/s0001-37652013005000036 ◽

2013 ◽

Vol 85 (2) ◽

pp. 575-584 ◽

Cited By ~ 12

Author(s):

MAURO C.L.M. OLIVEIRA ◽

MAURICIO B. DOS SANTOS ◽

DANIEL LOEBMANN ◽

ALEXANDRE HARTMAN ◽

ALEXANDRO M. TOZETTI

Keyword(s):

Species Richness ◽

Water Availability ◽

Plant Cover ◽

Abundant Species ◽

Thermal Variation ◽

Environmental Filter ◽

Anuran Species ◽

Drift Fence ◽

Pampa Biome ◽

The Relationship

This study aimed to verify the relationship between habitat and the composition of anuran species in dune and restinga habitats in southernmost Brazil. The habitats were sampled between April 2009 and March 2010 using pitfalls with drift fence. We have captured 13,508 individuals of 12 anuran species. Species richness was lower in the dunes and dominance was higher in the resting. Apparently the less complex plant cover, water availability, and wide daily thermal variation in dunes act as an environmental filter for frogs. This hypothesis is reinforced by the fact that the most abundant species (Physalaemus biligonigerus and Odonthoprynus maisuma) bury themselves in the sand, minimizing these environmental stresses. Despite being in the Pampa biome, the studied community was more similar to those of coastal restinga environment of southeast Brazil than with other of the Pampa biome. The number of recorded species is similar to those observed in other open habitats in Brazil, showing the importance of adjacent ones to the shoreline for the maintenance of the diversity of anurans in southernmost Brazil.

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Treeline ecotones shape the distribution of avian species richness and functional diversity in south temperate mountains

Scientific Reports ◽

10.1038/s41598-020-75470-2 ◽

2020 ◽

Vol 10 (1) ◽

Author(s):

Tomás A. Altamirano ◽

Devin R. de Zwaan ◽

José Tomás Ibarra ◽

Scott Wilson ◽

Kathy Martin

Keyword(s):

Species Richness ◽

Functional Diversity ◽

Functional Traits ◽

Habitat Structure ◽

Environmental Gradients ◽

Montane Forest ◽

Avian Species ◽

Point Counts ◽

Mountain Habitats ◽

Elevational Range

Abstract Mountains produce distinct environmental gradients that may constrain or facilitate both the presence of avian species and/or specific combinations of functional traits. We addressed species richness and functional diversity to understand the relative importance of habitat structure and elevation in shaping avian diversity patterns in the south temperate Andes, Chile. During 2010–2018, we conducted 2202 point-counts in four mountain habitats (successional montane forest, old-growth montane forest, subalpine, and alpine) from 211 to 1,768 m in elevation and assembled trait data associated with resource use for each species to estimate species richness and functional diversity and turnover. We detected 74 species. Alpine specialists included 16 species (22%) occurring only above treeline with a mean elevational range of 298 m, while bird communities below treeline (78%) occupied a mean elevational range of 1,081 m. Treeline was an inflection line, above which species composition changed by 91% and there was a greater turnover in functional traits (2–3 times greater than communities below treeline). Alpine birds were almost exclusively migratory, inhabiting a restricted elevational range, and breeding in rock cavities. We conclude that elevation and habitat heterogeneity structure avian trait distributions and community composition, with a diverse ecotonal sub-alpine and a distinct alpine community.

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Effects of oil palm plantations on anuran diversity in the eastern Amazon

Animal Biology ◽

10.1163/15707563-00002481 ◽

2015 ◽

Vol 65 (3-4) ◽

pp. 321-335 ◽

Cited By ~ 14

Author(s):

Fabricio S. Correa ◽

Leandro Juen ◽

Lenise C. Rodrigues ◽

Heriberto F. Silva-Filho ◽

Maria C. Santos-Costa

Keyword(s):

Land Use ◽

Species Richness ◽

Oil Palm ◽

Soil Conditions ◽

Total Abundance ◽

Anuran Species ◽

Forested Areas ◽

Acoustic Surveys ◽

Negative Impacts ◽

The Tropics

The extent of land use for oil palm plantations has grown considerably in the tropics due to climate, appropriate soil conditions for cultivation and its profitability. However, oil palm plantations may endanger biodiversity through reduction and fragmentation of forest areas. Herein we analyzed the effects on anuran species richness, composition and total abundance in oil palm plantations and surrounding forests in eastern Amazon. We installed seven plots in oil palm plantations and seven plots in surrounding forests, which we surveyed for the presence of anurans through active visual and acoustic surveys during periods of high and low rainfall levels. Anuran assemblages found in forests and oil palm plantations differed in species richness and composition, with a loss of 54% of species in oil palm plantations. No difference was observed in total abundance of anurans between both environments. While conversion of forests to oil palm plantations may result in less negative impacts on anuran diversity than other types of monocultures, such loss is nevertheless high, making the maintenance of relatively greater forested areas around oil palm plantations necessary in order to conserve anuran diversity.

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Complex Small-Holder Agriculture in Rainforest Buffer Zone, Sri Lanka, Supports Endemic Birds

Frontiers in Ecology and Evolution ◽

10.3389/fevo.2021.608434 ◽

2021 ◽

Vol 9 ◽

Author(s):

Juliana Hanle ◽

Balangoda M. P. Singhakumara ◽

Mark S. Ashton

Keyword(s):

Land Use ◽

Species Richness ◽

Sri Lanka ◽

Buffer Zone ◽

Small Scale ◽

Forest Fragments ◽

Buffer Zones ◽

Bird Abundance ◽

Point Counts ◽

Zone Management

The Sinharaja rainforest in southwestern Sri Lanka is a protected forest in a largely agriculture-dominated landscape. In keeping with global UNESCO global biosphere reserves planning, the Sinharaja is surrounded by a buffer zone of regenerating forest and villages with small tea plots and multi-strata tree gardens (homegardens). Globally, however, conservation planning lacks standards on buffer zone management. We ask what relationships exist between village land use and bird assemblages, which are effective ecosystem indicators. Birds have been little studied across land use and vegetation structure in actively managed, large, protected forest buffer zones. To that end, we ran spatially- and temporally-replicated bird point counts across tree gardens, forest fragments, and tea plots within a Sinharaja village. Tree gardens held a greater abundance of birds across habitat association, conservation concern, diet, and endemic species than forest fragments or tea plots. Forest fragments and tree gardens hosted statistically similar numbers of birds in some subsets, but their species assemblages differed. In tea plots, greater shade tree species richness correlated with greater bird abundance and species richness. Our results support the argument for programs to support complex small-scale tree-based agroforestry embedded in buffer zone regenerating forest.

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Patch size does not always indicate bird species diversity: case in peri-urban tropical habitat in Riau, Indonesia

IOP Conference Series Earth and Environmental Science ◽

10.1088/1755-1315/948/1/012028 ◽

2021 ◽

Vol 948 (1) ◽

pp. 012028

Author(s):

M K Alghifari ◽

A Mardiastuti ◽

Y A Mulyani

Keyword(s):

Species Richness ◽

Human Activities ◽

Bird Species ◽

Diversity Indices ◽

Early Morning ◽

Habitat Diversity ◽

Urban Habitat ◽

Large Patch ◽

Small Patch ◽

Point Counts

Abstract Larger patches generally are inhabited by higher species richness, including birds, as predicted by the island biogeography theory. The objective of this research was to reveal the response of bird species richness in different patch sizes in peri-urban habitat. The study site area was five patches (2 large patches near human activities, remote large patch with a small lake, small patch, corridor patch) of disturbed secondary shrub-forest in Riau University, Sumatra. Birds were observed using the standard point-counts in early morning and late afternoon (8 points/patch, 3 replicates, total 40 observation-hour) in March-April 2021. Species richness (S), Shannon-Wiener diversity indices (H’), Chao species prediction, and Bray-Curtis similarity indices (B) were calculated. Total of 979 individual birds were observed, consisted of 68 species from 28 families with B ranged from 0.573 to 0.846. Large patch with lake in remote area had the highest species richness (S:39 species, Chao:54) and H’ (3.097). However, two large patches closed to human activities had the lowest number of species (S:27, Chao:30, H’:2.908, and S:23, Chao:32, H’:2.938, respectively), even lower than small patch (S:30, Chao:40, H’:2.925) or corridor patch (S:34; Chao:51, H’:2.724). Clearly human disturbance and micro-habitat diversity affect species richness in a local scale.

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