Roadside Car Surveys: Methodological Constraints and Solutions for Estimating Parrot Abundances across the World

Parrots stand out among birds because of their poor conservation status and the lack of available information on their population sizes and trends. Estimating parrot abundance is complicated by the high mobility, gregariousness, patchy distributions, and rarity of many species. Roadside car surveys can be useful to cover large areas and increase the probability of detecting spatially aggregated species or those occurring at very low densities. However, such surveys may be biased due to their inability to handle differences in detectability among species and habitats. We conducted 98 roadside surveys, covering > 57,000 km across 20 countries and the main world biomes, recording ca. 120,000 parrots from 137 species. We found that larger and more gregarious species are more easily visually detected and at greater distances, with variations among biomes. However, raw estimates of relative parrot abundances (individuals/km) were strongly correlated (r = 0.86–0.93) with parrot densities (individuals/km2) estimated through distance sampling (DS) models, showing that variability in abundances among species (>40 orders of magnitude) overcomes any potential detectability bias. While both methods provide similar results, DS cannot be used to study parrot communities or monitor the population trends of all parrot species as it requires a minimum of encounters that are not reached for most species (64% in our case), mainly the rarest and more threatened. However, DS may be the most suitable choice for some species-specific studies of common species. We summarize the strengths and weaknesses of both methods to guide researchers in choosing the best–fitting option for their particular research hypotheses, characteristics of the species studied, and logistical constraints.

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Tendencias poblacionales recientes de la avutarda hubara en las Islas Canarias: análisis metodológico y estado de conservación

Animal Biodiversity and Conservation ◽

10.32800/abc.2012.35.0125 ◽

2012 ◽

Vol 35 (1) ◽

pp. 125-139

Author(s):

C. Schuster ◽

◽

J. J. Iglesias-Lebrija ◽

L. M. Carrascal ◽

◽

...

Keyword(s):

Canary Islands ◽

Conservation Status ◽

Distance Sampling ◽

Small Variation ◽

Population Trends ◽

Line Transect ◽

Sampling Area ◽

Average Value ◽

Houbara Bustard ◽

Population Sizes

Recent population trends of the houbara bustard in the Canary Islands. Methods and conservation status Determining conservation status requires rigorous and reliable data about population sizes and trends, especially if they have to be applied to islands where the species have small populations. The Canary bustard houbara (Chlamydotis undulata fuertaventurae) is catalogued as ‘in danger’ by the Red Book of the Birds of Spain. This work analyzes the value of previously published information on the species using the method of adjacent linear transects separated by 200 m, as a baseline for establishing robust population trends in 30 important areas (ranging from 1.3 to 12.8 km2) for the houbara in the islands of Lanzarote and Fuerteventura (Canary Islands). Censuses were repeated on the same dates (from November to December) and localities as those carried out in 1994, 2004 and 2006. The detection probability of the houbara was estimated by means of distance sampling, being 0.42 up to 250 m from the observer, and 0.82 in the main census belt of 100 m on either side of the line transect. The method of adjacent linear transects —counting the maximum number of hubaras detected— provides accurate figures of population densities (detection of 95.2% of the birds). The previous estimations of houbara densities can therefore be considered highly trustworthy, with a probable average underestimation of only 5 %. Nevertheless, the confidence intervals of density estimations using only one census were very large. Therefore, with only one census per sampling area and year it is not possible to obtain precise estimates of houbara densities with small variation around the average value. This raises concern when trying to obtain solid evidence about the increases–decreases of houbara populations comparing different dates or study areas. The density of the Canary Island hubara bustard decreased significantly from 2004/2006 to 2011 in eight areas of Fuerteventura (Vega Vieja, Los Alares–Pocetas, Matas Blancas, Lorenzo– Diviso, Corralejo, Lajares and Fimapaire) and in two areas of Lanzarote (Argana and La Santa). Conversely, the density of the houbara significantly increased in three areas of Lanzarote (Zonzamas, Guatiza and Llano de las Maretas). As a whole, average population density did not differ significantly between 2004/2006 and 2011 in Fuerteventura (slight decrease of 29% in 2011), but there was a significant increase in Lanzarote (increase of 60% from 2004/2006 to 2011). The change in density from 2004/2006 to 2011 tended to be an increase in areas further from paved roads, and a decrease in locations predominantly covered by loose sandy soils.

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Using encounter rates as surrogates for density estimates makes monitoring of heavily-traded grey parrots achievable across Africa

Oryx ◽

10.1017/s0030605315000484 ◽

2015 ◽

Vol 50 (4) ◽

pp. 617-625 ◽

Cited By ~ 12

Author(s):

Stuart J. Marsden ◽

Emmanuel Loqueh ◽

Jean Michel Takuo ◽

John A. Hart ◽

Robert Abani ◽

...

Keyword(s):

Local Density ◽

Conservation Status ◽

Distance Sampling ◽

Central Africa ◽

High Mobility ◽

Encounter Rate ◽

Line Transect ◽

African Countries ◽

Density Estimates ◽

Encounter Rates

AbstractEstimating population sizes in the heavily traded grey parrots of West and Central Africa would provide insights into conservation status and sustainability of harvests. Ideally, density estimates would be derived from a standardized method such as distance sampling, but survey efforts are hampered by the extensive ranges, patchy distribution, variable abundance, cryptic habits and high mobility of the parrots as well as by logistical difficulties and limited resources. We carried out line transect distance sampling alongside a simpler encounter rate method at 10 sites across five West and Central African countries. Density estimates were variable across sites, from 0–0.5 individuals km−2 in Côte d'Ivoire and central Democratic Republic of the Congo to c. 30 km−2 in Cameroon and > 70 km−2 on the island of Príncipe. Most significantly, we identified the relationship between densities estimated from distance sampling and simple encounter rates, which has important applications in monitoring grey parrots: (1) to convert records of parrot groups encountered in a day's activities by anti-poaching patrols within protected areas into indicative density estimates, (2) to confirm low density in areas where parrots are so rare that distance sampling is not feasible, and (3) to provide a link between anecdotal records and local density estimates. Encounter rates of less than one parrot group per day of walking are a reality in most forests within the species’ ranges. Densities in these areas are expected to be one individual km−2 or lower, and local harvest should be disallowed on this basis.

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A multi-bioassay integrated approach to assess antifouling potential of extracts from the Mediterranean sponge Ircinia oros

Environmental Science and Pollution Research ◽

10.1007/s11356-021-15683-8 ◽

2021 ◽

Author(s):

Lucia De Marchi ◽

Carlo Pretti ◽

Alessia Cuccaro ◽

Matteo Oliva ◽

Federica Tardelli ◽

...

Keyword(s):

Developmental Stages ◽

Integrated Approach ◽

Common Species ◽

Marine Diatom ◽

Cellular Damage ◽

Inhibition Of Growth ◽

Aliivibrio Fischeri ◽

The Mediterranean ◽

Ircinia Oros ◽

Species Specific

AbstractThe phylum Porifera and their symbionts produce a wide variety of bioactive compounds, playing a central role in their ecology and evolution. In this study, four different extracts (obtained by non-polar and semi-polar extraction methodologies) of the Mediterranean sponge Ircinia oros were tested through a multi-bioassay integrated approach to assess their antifouling potential. Tests were performed using three common species, associated with three different endpoints: the marine bacterium Aliivibrio fischeri (inhibition of bioluminescence), the marine diatom Phaeodactylum tricornutum (inhibition of growth), and different development stages of the brackish water serpulid Ficopomatus enigmaticus (gametes: sperm motion, vitality inhibition and cellular damage; larvae: development; adults: AChE (acetylcholinesterase)-inhibitory activity). The effects of extracts were species specific and did not vary among different extraction methodologies. In particular, no significant reduction of bioluminescence of A. fischeri was observed for all tested samples. By contrast, extracts inhibited P. tricornutum growth and had toxic effects on different F. enigmaticus’ developmental stages. Our results suggest that the proposed test battery can be considered a suitable tool as bioactivity screening of marine natural products.

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Spatial distribution of the Barbary Partridge (Alectoris barbara) in Sardinia explained by land use and climate

European Journal of Wildlife Research ◽

10.1007/s10344-021-01519-w ◽

2021 ◽

Vol 67 (4) ◽

Author(s):

Gianpasquale Chiatante ◽

Marta Giordano ◽

Anna Vidus Rosin ◽

Oreste Sacchi ◽

Alberto Meriggi

Keyword(s):

Land Use ◽

Conservation Status ◽

Distance Sampling ◽

Strong Relationship ◽

European Population ◽

Factors Affecting ◽

Brood Rearing ◽

Management Actions ◽

Negative Effect ◽

Study Sites

AbstractMore than half of the European population of the Barbary Partridge is in Sardinia; nonetheless, the researches concerning this species are very scarce, and its conservation status is not defined because of a deficiency of data. This research aimed to analyse the habitat selection and the factors affecting the abundance and the density of the Barbary Partridge in Sardinia. We used the data collected over 8 years (between 2004 and 2013) by spring call counts in 67 study sites spread on the whole island. We used GLMM to define the relationships between the environment (topography, land use, climate) both the occurrence and the abundance of the species. Moreover, we estimated population densities by distance sampling. The Barbary Partridge occurred in areas at low altitude with garrigue and pastures, avoiding woodlands and sparsely vegetated areas. We found a strong relationship between the occurrence probability and the climate, in particular, a positive relation with temperature and a negative effect of precipitation, especially in April–May, during brood rearing. Furthermore, dry crops positively affected the abundance of the species. We estimated a density of 14.1 partridges per km2, similar to other known estimates. Our findings are important both because they increase the knowledge concerning this species, which is considered data deficient in Italy, and because they are useful to plan management actions aimed to maintain viable populations if necessary.

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Profile of a mammalian sperm receptor

Development ◽

10.1242/dev.108.1.1 ◽

1990 ◽

Vol 108 (1) ◽

pp. 1-17 ◽

Cited By ~ 2

Author(s):

P.M. Wassarman

Keyword(s):

Gene Expression ◽

Zona Pellucida ◽

Specific Gene ◽

Mammalian Development ◽

Unique Nature ◽

Mammalian Fertilization ◽

Species Specific ◽

Available Information ◽

Mammalian Eggs ◽

Sperm Receptor

Complementary molecules on the surface of eggs and sperm are responsible for species-specific interactions between gametes during fertilization in both plants and animals. In this essay, several aspects of current research on the mouse egg receptor for sperm, a zona pellucida glycoprotein called ZP3, are addressed. These include the structure, synthesis, and functions of the sperm receptor during oogenesis and fertilization in mice. Several conclusions are drawn from available information. These include (I) ZP3 is a member of a unique class of glycoproteins found exclusively in the extracellular coat (zona pellucida) of mammalian eggs. (II) ZP3 gene expression is an example of oocyte-specific and, therefore, sex-specific gene expression during mammalian development. (III) ZP3 is a structural glycoprotein involved in assembly of the egg extracellular coat during mammalian oogenesis. (IV) ZP3 is a sperm receptor involved in carbohydrate-mediated gamete recognition and adhesion during mammalian fertilization. (V) ZP3 is an inducer of sperm exocytosis (acrosome reaction) during mammalian fertilization. (VI) ZP3 participates in the secondary block to polyspermy following fertilization in mammals. (VII) The extracellular coat of other mammalian eggs contains a glycoprotein that is functionally analogous to mouse ZP3. The unique nature, highly restricted expression, and multiple roles of ZP3 during mammalian development make this glycoprotein a particularly attractive subject for investigation at both the cellular and molecular levels.

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The influence of animal mobility on the assumption of uniform distances in aerial line-transect surveys

Wildlife Research ◽

10.1071/wr07077 ◽

2008 ◽

Vol 35 (4) ◽

pp. 275 ◽

Cited By ~ 31

Author(s):

Rachel M. Fewster ◽

Colin Southwell ◽

David L. Borchers ◽

Stephen T. Buckland ◽

Anthony R. Pople

Keyword(s):

Survey Design ◽

Distance Sampling ◽

High Mobility ◽

Line Transect ◽

Transect Line ◽

Aerial Surveys ◽

Pack Ice ◽

Capture Recapture ◽

Distance Data ◽

Crabeater Seals

Line-transect distance sampling is a widely used method for estimating animal density from aerial surveys. Analysis of line-transect distance data usually relies on a requirement that the statistical distribution of distances of animal groups from the transect line is uniform. We show that this requirement is satisfied by the survey design if all other assumptions of distance sampling hold, but it can be violated by consistent survey problems such as responsive movement of the animals towards or away from the observer. We hypothesise that problems with the uniform requirement are unlikely to be encountered for immobile taxa, but might become substantial for species of high mobility. We test evidence for non-uniformity using double-observer distance data from two aerial surveys of five species with a spectrum of mobility capabilities and tendencies. No clear evidence against uniformity was found for crabeater seals or emperor penguins on the pack-ice in East Antarctica, while minor non-uniformity consistent with responsive movement up to 30 m was found for Adelie penguins. Strong evidence of either non-uniformity or a failure of the capture–recapture validating method was found for eastern grey kangaroos and red kangaroos in Queensland.

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Locally rare species influence grassland ecosystem multifunctionality

Philosophical Transactions of the Royal Society B Biological Sciences ◽

10.1098/rstb.2015.0269 ◽

2016 ◽

Vol 371 (1694) ◽

pp. 20150269 ◽

Cited By ~ 67

Author(s):

Santiago Soliveres ◽

Peter Manning ◽

Daniel Prati ◽

Martin M. Gossner ◽

Fabian Alt ◽

...

Keyword(s):

Land Use ◽

Rare Species ◽

Common Species ◽

Ecosystem Functions ◽

Individual Species ◽

Conservation Priorities ◽

Below Ground ◽

Species Specific ◽

The Relationship ◽

Ecosystem Multifunctionality

Species diversity promotes the delivery of multiple ecosystem functions (multifunctionality). However, the relative functional importance of rare and common species in driving the biodiversity–multifunctionality relationship remains unknown. We studied the relationship between the diversity of rare and common species (according to their local abundances and across nine different trophic groups), and multifunctionality indices derived from 14 ecosystem functions on 150 grasslands across a land-use intensity (LUI) gradient. The diversity of above- and below-ground rare species had opposite effects, with rare above-ground species being associated with high levels of multifunctionality, probably because their effects on different functions did not trade off against each other. Conversely, common species were only related to average, not high, levels of multifunctionality, and their functional effects declined with LUI. Apart from the community-level effects of diversity, we found significant positive associations between the abundance of individual species and multifunctionality in 6% of the species tested. Species-specific functional effects were best predicted by their response to LUI: species that declined in abundance with land use intensification were those associated with higher levels of multifunctionality. Our results highlight the importance of rare species for ecosystem multifunctionality and help guiding future conservation priorities.

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Resurrection of the Butterfly-winged Comber, Serranus papilionaceus Valenciennes, 1832 (Teleostei, Serranidae) and its phylogenetic position within genus Serranus

ZooKeys ◽

10.3897/zookeys.1017.60637 ◽

2021 ◽

Vol 1017 ◽

pp. 111-126

Author(s):

Adriana Vella ◽

Noel Vella ◽

Carolina Acosta-Díaz

Keyword(s):

Conservation Status ◽

Valid Species ◽

Phylogenetic Position ◽

Mitochondrial Coi ◽

Interspecific Divergence ◽

Population Conservation ◽

Status Assessment ◽

Morphological Differences ◽

Species Specific ◽

High Level

The family Serranidae is represented by 92 genera and 579 valid species, with the genus Serranus Cuvier, 1816, containing 30 species. In this study, specimens of Butterfly-winged Comber, Serranus papilionaceus Valenciennes, 1832, were collected from the Canary Islands and compared morphologically and genetically to Painted Comber, Serranus scriba (Linnaeus, 1758), from the Mediterranean Sea. Morphological differences, especially in the colour banding pattern, were corroborated by genetic differences in mitochondrial (COI and ND2) and nuclear (Rhod and PTR) markers. The mitochondrial DNA markers revealed a high level of divergence and no shared haplotypes between the two species (interspecific divergence: COI 4.31%; ND2 8.68%), and a phylogenetic analysis showed that these two species are closely related sister species sharing common ancestry. This study is therefore offering to resurrect S. papilionaceus Valenciennes, 1832 as a valid species increasing the number of eastern Atlantic Serranus species to 11. This should direct new species-specific research, including its population conservation status assessment across its distribution.

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DNA barcode identification of commercial fish sold in Mexican markets

Genome ◽

10.1139/gen-2017-0222 ◽

2018 ◽

Vol 61 (6) ◽

pp. 457-466 ◽

Cited By ~ 8

Author(s):

Stephanie Sarmiento-Camacho ◽

Martha Valdez-Moreno

Keyword(s):

Conservation Status ◽

Dna Barcode ◽

Common Species ◽

Morphological Identification ◽

Dna Barcodes ◽

Commercial Fish ◽

Sphyrna Lewini ◽

Pangasianodon Hypophthalmus ◽

Makaira Nigricans ◽

The Status

The substitution of high-value fish species for those of lower value is common practice. Although numerous studies have addressed this issue, few have been conducted in Mexico. In this study, we sought to identify fresh fillets of fish, sharks, and rays using DNA barcodes. We analyzed material from “La Viga” in Mexico City, and other markets located on the Gulf and Caribbean coasts of Mexico. From 134 samples, we obtained sequences from 129, identified to 9 orders, 28 families, 38 genera, and 44 species. The most common species were Seriola dumerili, Pangasianodon hypophthalmus, Carcharhinus falciformis, Carcharhinus brevipinna, and Hypanus americanus. Pangasianodon hypophthalmus was most commonly used as a substitute for higher-value species. The substitution rate was 18% of the total. A review of the conservation status of the specimens identified against the IUNC list enabled us to establish that some species marketed in Mexico are threatened: Makaira nigricans, Lachnolaimus maximus, Hyporthodus flavolimbatus, and Isurus oxyrinchus are classified as vulnerable; Lopholatilus chamaeleonticeps and Sphyrna lewini are endangered; and the status of Hyporthodus nigritus is critical. These results will demonstrate to the Mexican authorities that DNA barcoding is a reliable tool for species identification, even when morphological identification is difficult or impossible.

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A Comparison of White-Winged Dove Zenaida asiatica Densities Estimated During Morning and Evening Surveys

Journal of Fish and Wildlife Management ◽

10.3996/092011-jfwm-059 ◽

2012 ◽

Vol 3 (1) ◽

pp. 158-163 ◽

Cited By ~ 1

Author(s):

Michael F. Small ◽

Joseph A. Veech ◽

John T. Baccus

Keyword(s):

Distance Sampling ◽

Visual Observation ◽

Probability Of Detection ◽

Reasonable Assumption ◽

Zenaida Asiatica ◽

Density Estimates ◽

Bird Populations ◽

Game Birds ◽

Population Sizes ◽

Cost Efficient

Abstract Surveying bird populations through visual observation is generally limited to morning. The focus on morning surveys is based on the reasonable assumption that detection is more likely when birds are most active. However, population surveys could become more time- and cost-efficient if both morning and evening sampling were equally effective, particularly for game birds, such as white-winged dove Zenaida asiatica. Texas Parks and Wildlife Department has recently implemented distance sampling to estimate population sizes and monitor an ongoing range expansion of this species. We compared morning vs. evening density estimates for white-winged doves sampled in Mason, Texas, on six separate occasions during summer 2006. Program DISTANCE (version 5.0) calculated similar detection probabilities and density estimates between paired morning and evening sampling periods. Probability of detection ranged from 0.27 to 0.46 for both morning and evening samples. Densities, in individuals/ha, ranged from 2.54 to 4.02 for morning sampling and 2.48 to 4.31 for evening sampling. In addition, variables (number of observations, cluster size, distance to cluster) used by DISTANCE did not vary substantially between morning and evening surveys. Our results suggest evening surveys are as effective as the conventional protocol of surveying white-winged doves only in the morning. Additional studies, using Program DISTANCE, should be conducted to similarly evaluate other species.

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