abundance index
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H-INDEX

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2021 ◽  
Author(s):  
Emiliano Arona ◽  
Adrián Schiavini

Abstract Free roaming dogs (FRD) in cities represent an increasing problem. Authorities need numbers of FRDs to evaluate policies implemented and to monitor the dog population. We estimated the number of FRD in Ushuaia city, Argentina, using a photographic capture-recapture methodology. We estimated an abundance index, the power to detect changes in the index, and modeled factors that may explain the spatial distribution of FRD and their welfare status. During three surveys, covering 72 transects along streets (9.9% of the street layout of Ushuaia), we recorded 539 different FRDs. A model with individual heterogeneity in capture-recapture probability gave 12,797 FRDs (95% CI 10,979 − 15,323), reflecting a dog:human relation of 1:6, higher than the relation recommended by the WHO. The abundance index was similar between surveys (8.13 ± 1.36, 8.38 ± 1.46 and 9.55 ± 1.28 dogs/km). The difference needed to detect changes in the index is about twice the standard error of estimates. The best model explaining dogs’ abundance included only geographical location, although two neighbourhoods with 9 transects stand out with 181 different FRDs identified. Together with the good overall dogs’ welfare status, modeling suggests that the behavior of owners is the main driver for the presence of FRDs. We recommend the use of photographic capture-recapture methodologies instead of simple index estimation, due to the small additional effort required and the improved accuracy and precision obtained. We also recommend a permanent systematic design for future surveys, increase the number of survey occasions, and improve the survey process.


2021 ◽  
Vol 22 (11) ◽  
Author(s):  
IFHAM FUADI RAMBE ◽  
Ridahati Rambey ◽  
SAHLAN SIREGAR

Abstract. Rambe IF, Rambey R, Siregar S. 2021. Species diversity, abundance, and wildlife conservation status in Batang Gadis National Park, North Sumatra, Indonesia. Biodiversitas 22: 5189-5196. Indonesia is one of the countries with the highest biodiversity in the world. Furthermore, the biodiversity of floral and faunal species is still being monitored and maintained, one of which is in the forest of the National Park. Batang Gadis National Park is a habitat for various species of endemic Sumatran wildlife, most of which are endangered species in the world. Therefore, this study aimed to inventory wild animals and to calculate their abundance in the Batang Gadis National Park. The study used camera traps as recording devices that were installed on permanent and non-permanent plots based on evidential animal trajectories in the National Park Management Section Region III Resort 7 Forest of Ampung Padang Forest in 2018. In the permanent plot, 10 species were documented within nine families, namely the Felidae, Tapiridae, Cervidae, Viverridae, Ursidae, Tragulidae, Suidae, Tupaiidae, and the Cercopithecidae. The highest species abundance was Macaca nemestrina (36.17%), and the second-highest was Muntiacus muntjak Zimmermann (14.89%), and then Tapirus indicus Desmarest (10,64%). Also, the Sumatran tiger (Panthera tigris sumatrae Pocock) was in the fourth position with a value of 10.63% of species abundance. Meanwhile, the lowest abundance index value was from clouded leopard (Neofelis diardi Cuvier) with 2.12%. The abundance of species from the non-permanent plots using camera trap documented a total of 13 species with 12 families namely Felidae, Tapiridae, Cervidae, Hystricidae, Viverridae, Muridae, Phasianidae, Tragulidae, Suidae, Muscicapidae, Tupaiidae, and Cercopithecidae. The highest was documented from wild boar (Sus scrofa Linnaeus) at 42.48% and the second-highest species abundance was macaque (N. nemestrina) at 26.144%. The lowest species abundance index values were tapir (T. indicus) and Javan blue robin (Myiomela diana Lesson) with 0,33% and 0,33 %, respectively. The existence of documented wildlife species in our study affirmsed the importance of Batang Gadis National Park as a natural habitat for some key and protected species.


Author(s):  
Emily Dennis ◽  
Calliste Fagard-Jenkin ◽  
Byron Morgan

1. The Generalised Abundance Index (GAI) provides a useful tool for estimating relative population sizes and trends of seasonal invertebrates from species’ count data, and offers potential for inferring which external factors may influence phenology and demography through parametric descriptions of seasonal variation. 2. We provide an R package that extends previous software with the ability to include covariates when fitting parametric GAI models, where seasonal variation is described by either a mixture of Normal distributions or a stopover model which provides estimates of lifespan. The package also generalises the model to allow any number of broods/generations in the target population within a defined season. The option to perform bootstrapping, either parametrically or non-parametrically, is also provided. 3. The new package allows models to be far more flexible when describing seasonal variation, which may be dependent on site-specific environmental factors or consist of many broods/generations which may overlap, as demonstrated by two case studies. 4. Our open-source software, available at \href{https://github.com/calliste-fagard-jenkin/GAI}{https://github.com/calliste-fagard-jenkin/rGAI}, makes this extension widely and freely available, allowing the complexity of GAI models used by ecologists and applied statisticians to increase accordingly.


Diversity ◽  
2021 ◽  
Vol 13 (10) ◽  
pp. 456
Author(s):  
Dionísio Virgílio Roque ◽  
Thomas Göttert ◽  
Valério António Macandza ◽  
Ulrich Zeller

This study is the first systematic assessment of large herbivore (LH) communities in Limpopo National Park (LNP) in Mozambique, an area where most LH species were extinct until the early 2000s. We investigate whether LH community parameters are linked with the availability of habitat types or the distance between sampling sites and the origin of LH resettlement. We placed camera traps in five habitat types in resettled and not-resettled areas to compare species richness, relative abundance index, grazers–browsers–mixed feeder ratio and naïve occupancy of 15 LH species. While the richness decreased along the distance gradient of LH resettlement, relative abundance index strongly responded to habitat features. Among habitat types, the browsers ratio oscillated, while from resettled to not-resettled areas, the ratio increased. Most species showed a wider distribution range among habitat types. The associations of most LH community parameters with habitat types rather than distance to initial release, together with the species-specific and guild-specific response patterns of LH, suggest LNP to already be in an intermediate stage of restoration. Our results highlight the importance of post-release monitoring of reintroduced wildlife as a tool to assess the success of ecological restoration initiatives in transboundary conservation areas.


2021 ◽  
Vol 9 (2) ◽  
pp. 59
Author(s):  
Rivaldo A Wuisan ◽  
Erly Kaligis

Crab of the genus Uca is one type of crustacean that makes mangroves a habitat to carry out their life cycle in order to remain sustainable. The purpose of this research is to identify the first, the second is to calculate the abundance, species diversity, dominance, and the third is to know the state of the aquatic environment around pH, temperature, salinity and substrate. The method used is the cruising method and the quadratic line transect method. The method of roaming as far as 300 m. While the line transect method is carried out by drawing three transect lines along 28 m. The identification results in Meras waters found 6 species. Based on data analysis using the cruising method, the number of individuals in Meras waters is 383 individuals, while in Molas waters there are 210 individuals. Based on data analysis using the quadratic line transect method, the species abundance index in Meras waters is 6,767 ind/m2, while in Molas waters it is 4,533 ind/m2. The value of H' at two locations is moderate. The value of C in two locations is low.   Keywords: Meras, Molas, Crabs, abundance, species diversity, dominance.


2021 ◽  
Author(s):  
Edgar Bernat-Ponce ◽  
David Ferrer ◽  
José A. Gil-Delgado ◽  
Germán M. López-Iborra

AbstractUrbanisation processes are increasing worldwide at surprising rates affecting wildlife in many ways: changing habitat structure, reducing resources, and modifying the distribution, composition and abundance of local biota. In different countries, urban waste collection techniques are evolving and surface rubbish containers (neighbourhood receptacles for temporarily storing anthropogenic household waste located above-ground on the streets) are being replaced with underground ones (metal boxes with steel chutes that fed into large underground containers) to improve sanitation measures, to avoid bad smells and waste scattering by animals. We aimed to detect if House Sparrows were more abundant close to surface rubbish containers than close to the underground ones. We recorded an abundance index of House Sparrows during two visits in winter 2018–2019 to point counts located in groups of both container types (80 and 85 groups of underground and surface containers, respectively) in eight towns of Eastern Spain. We modelled the abundance index according to rubbish container type, and 14 other environmental variables at four scales: container, nearest buildings, near urban features, and general locality features using GLMMs. House Sparrows were more abundant close to surface than to underground rubbish containers, which may be linked with higher food debris availability. The presence of other urban features (bar terraces, private gardens, mature trees) interacting with the rubbish containers also influenced the abundance of House Sparrows. The replacement of above-ground rubbish containers with underground ones may deprive House Sparrows resources, which could lead to the decline of this species, especially in urban areas with little green cover.


2021 ◽  
Vol 13 (6) ◽  
pp. 18655-18659
Author(s):  
A.A. Kazi ◽  
D.N. Rabari ◽  
M.I. Dahya ◽  
S. Lyngdoh

The Dhole Cuon alpinus used to be the meso carnivore of the forests throughout Indian subcontinent; however, habitat loss, low prey biomass, and human disturbance exterminated the species from India’s 60% historic range, and the numbers are less than 1,500 individuals in wild.  Following the same shrinking trend, Dholes were extirpated from Gujarat.  A few doubtful sightings and inevident reportings generated ambiguity of Dhole presence in Gujarat.  We conducted a study in Vansda National Park with 15,660 trap nights at 30 trap locations, and have confirmed the rediscovery of Dholes in Gujarat after 70 years.  We estimated the Dhole’s minimum home range as 13.7km2 and also analyzed relative abundance index of other mammals.  The future retention of Dholes requires detailed range, diet, and adaption studies along with conservational efforts to reduce re-extinction probabilities.


2021 ◽  
Vol 15 (1) ◽  
pp. 16-24
Author(s):  
A. V. Burakova ◽  
E. A. Malkova

The purpose of the research is to study the parasite fauna of the common frog (Rana temporaria Linnaeus, 1758) inhabiting the vicinity of the Visim Nature Biosphere Reserve.Materials and methods. The species composition, dominance structure and endoparasite infection of 32 individuals of R. temporaria caught along the banks of the upper reaches of the Sulem Riverwere assessed according to the following indicators: the prevalence and intensity of infection and abundance index.Results and discussion. The species composition of parasites in a common frog from the vicinity of the Visim Nature Biosphere Reserve is presented for the first time. Five species of macroparasites have been identified, classified as Nematoda: Oswaldocruzia filiformis (Goeze, 1782), Neoraillietnema praeputiale (Skrjabin, 1916), Cosmocerca ornata (Dujardin, 1845), Rhabdias bufonis (Schrank, 1788) and as Platyhelminthes: Haplometra cylindracea (Zeder, 1800). One species of endosymbiotic protozoa of Chromista, Opalina ranarum was recorded (Purkinje et Valentin, 1835). The prevalence of the infection of common frogs by helminths reaches 100%, the abundance index is 11.06, and protozoa is 93.8% and 62.16, respectively. Nematodes O. filiformis (the prevalence of infection 96.9%, and abundance index 7.97) and R. bufonis (the prevalence of infection 46.9%, abundance index 2.28) predominate. It was shown that nematode N. praeputiale was not found in the parasitocenosis of immature amphibians, and trematode H. cylindracea was not found in adult animals. The proportion of O. filiformis and C. ornata increases with age in common frogs. It was found that the animals of the July population are infected with nematode R. bufonis largely. Regardless of the age of R. temporaria, the probability of colonization by O. ranarum in spring will be higher.


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