Description
The line transect method was applied to assess the linear index of abundance and community structure of birds breeding in an area of Kalahari woodland used as range land for cattle. Four transects were designed along roads traversing the ranch. Each transect was 2.5 km long and was surveyed three times in 2014 and 2015. A total of 47 bird species were recorded but only 25-31 species were recorded on any particular transect. In the neighbouring pristine Kalahari woodland, the number of bird species on a12 km long transect was much higher (n = 88), and ranged in some sections (each 1.2 km in length) from 35 to 53. On any particular section, the number of dominant species ranged from 5 to 7, and their cumulative dominance on each section was similar, ranging from 53-56%, while the community dominance index ranged from 0.23 to 0.35. The most numerous species were the Cape turtle dove and emerald-spotted wood dove, which were dominant on all sections. Together they comprised 28% of all breeding birds. The avian community in the Kalahari woodland in Sachinga LDC did not differ from the neighbouring pristine woodland either in terms of species diversity or evenness. However, it differed significantly in terms of species richness, the proportion of main ecological guilds, and linear index of abundance of particular species. These differences could be mainly due to the structure of woody vegetation, which is much thicker in Sachinga than in the pristine woodland not used as pasture for cattle. The thickening of this vegetation on the ranch could have been caused by heavy grazing pressure by the cattle.
Enregistrements de données
Les données de cette ressource occurrence ont été publiées sous forme d'une Archive Darwin Core (Darwin Core Archive ou DwC-A), le format standard pour partager des données de biodiversité en tant qu'ensemble d'un ou plusieurs tableurs de données. Le tableur de données du cœur de standard (core) contient 47 enregistrements.
Cet IPT archive les données et sert donc de dépôt de données. Les données et métadonnées de la ressource sont disponibles pour téléchargement dans la section téléchargements. Le tableau des versions liste les autres versions de chaque ressource rendues disponibles de façon publique et permet de tracer les modifications apportées à la ressource au fil du temps.
Versions
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Comment citer
Les chercheurs doivent citer cette ressource comme suit:
Kopij, G., 2020. Abundance and community structure of birds breeding in Kalahari woodland used as rangeland. Museu de Ciències Naturals de Barcelona. Dataset/Occurrence: https://doi.org/10.15470/rova7r
Droits
Les chercheurs doivent respecter la déclaration de droits suivante:
L’éditeur et détenteur des droits de cette ressource est Museu de Ciències Naturals de Barcelona. Ce travail est sous licence Creative Commons Attribution (CC-BY) 4.0.
Enregistrement GBIF
Cette ressource a été enregistrée sur le portail GBIF, et possède l'UUID GBIF suivante : 792a2342-1dbb-459b-84cd-e6eb1f9ba6c9. Museu de Ciències Naturals de Barcelona publie cette ressource, et est enregistré dans le GBIF comme éditeur de données avec l'approbation du GBIF Spain.
Mots-clé
Community ecology; Population densities; Rangeland management; Occurrence; Occurrence
Contacts
- Fournisseur Des Métadonnées ●
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- Personne De Contact
http://orcid.org/0000-0002-6712-8472
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Couverture géographique
The study was conducted in the Sachinga Livestock Development Centre of the Ministry of Agriculture of the Namibian Government. The centre is situated in NE Namibia, in the Zambezi region, about 40 km west of Katima Mulilo, between S17.39.40-S17.40.20 and E 24.23.55-E24.24.02. The Centre is a ranch of 3,243 ha. Most of the Sachinga LDC is covered by teak woodland, with smaller portion of Burkea-Kisat-False Mopane woodland and Omuramba grassland. The natural vegetation is well-preserved and represented by three classes of Kalahari woodland: 1) Colophospermum mopane , with two dominant associations: Nymphaea nouchali–Eragrostis rotifer which contains water species, and Combretum imberbe–Acacia nigrescens in association with sparse woodlands; 2) Baikiaea plurijuga woodland, comprising Guibourtia coleospherma–Burkea africana Association and Combretum collinum–Boscia albitrunca association; and 3) Baikiaea plurijuga – Terminalia sericea class with Pterocarpus angolensis–Diploryhnchus condylocarpon association, Dalbergia martinii–Berchemia discolor association, and Acacia fleckii–Baphia massaiensis association (Lushetile, 2009).
| Enveloppe géographique | Sud Ouest [-24,24, 17,39], Nord Est [-24,23, 17,4] |
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Couverture taxonomique
Pas de description disponible
| Family | Alcedinidae, Bucerotidae, Buphagidae, Caprimulgidae, Cisticolidae, Columbidae, Coraciidae, Dicruridae, Emberizidae, Estrildidae, Laniidae, Leiothrichidae, Macrosphenidae, Malaconotidae, Meropidae, Monarchidae, Muscicapidae, Nectariniidae, Numididae, Oriolidae, Paridae, Phasianidae, Phoeniculidae, Picidae, Platysteiridae, Pycnonotidae, Sturnidae, Trogonidae, Vangidae, Vangidae |
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Couverture temporelle
| Date de début / Date de fin | 2014-09-03 / 2015-04-29 |
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Données sur le projet
In all parts of Africa, the expansion and intensity of agriculture pose a major threat to biodiversity through the conversion of natural habitats to agrocenosis, fragmentation and degradation. However, in some places, where selected biota were carefully surveyed in agrocenosis, it has been shown that they may also well preserve certain communities, for example birds (Kopij, 1998, 2006, 2013, 2015, 2018; Ratclife and Crowe, 2001; Balwig et al., 2006; Humle, 2007; Mulwa et al., 2012; Nadng’ang’a et al., 2013). This is especially evident when traditional agriculture is established within woodlands and wet savannas. One of the largest broadleaved savanna type forests in Namibia is the Kalahari woodland. It occupies about 600,000 km2 in Kavango West, Kavango East, Zambezi, and eastern parts of Ohangwena and Oshikoto regions (Mendelsohn et al., 2009). This ecoregion supports a rich and diverse fauna that includes large populations of elephant Loxodonta africana, black rhino Diceros bicornis, white rhino Cerathotherium simum, leopard Panthera pardus, and wild dog Lycaon pictus (G. Kopij, own data). Nearly 500 bird species have been recorded in this biome (Kopij, 2016, 2017). Due to the scarcity of surface water, until rather recently, the Kalahari woodland was sparsely occupied by people, but in recent decades, human populations have been increasing and the cattle industry is growing, with far-reaching effects on the environment and wildlife (Mendelsohn et al., 2009). Every year, at least 1,000,000 m3 of raw timber harvested from this forest is shipped from Walvis Bay port to China (G. Kopij, own data). It is therefore essential to closely monitor and measure the resulting threats to the biodiversity and the whole ecosystem. This may help to formulate strategies and policies to protect this precious biome from widespread fragmentation, destruction, and degradation. The purpose of this study was to estimate population densities and dominance of bird species occurring in Kalahari woodland used for cattle grazing and to compare these ecological parameters with the same habitat that remains in a pristine stage.
| Titre | Abundance and community structure of birds breeding in Kalahari woodland used as rangeland |
|---|---|
| Description du domaine d'étude / de recherche | The study was conducted in the Sachinga Livestock Development Centre of the Ministry of Agriculture of the Namibian Government. The centre is situated in NE Namibia, in the Zambezi region, about 40 km west of Katima Mulilo (fig. 1), between S17.39.40-S17.40.20 and E 24.23.55-E24.24.02. The Centre is a ranch of 3,243 ha. The aim of the centre is in situ conservation, livestock improvement programmes and provision of breeding animals to the farmers, and farmer education. The centre is surrounded by communal areas with subsistence farming. Most of the Sachinga LDC is covered by teak woodland, with smaller portion of Burkea-Kisat-False Mopane woodland and Omuramba grassland. The natural vegetation is well-preserved and represented by three classes of Kalahari woodland: 1) Colophospermum mopane , with two dominant associations: Nymphaea nouchali–Eragrostis rotifer which contains water species, and Combretum imberbe–Acacia nigrescens in association with sparse woodlands; 2) Baikiaea plurijuga woodland, comprising Guibourtia coleospherma–Burkea africana Association and Combretum collinum–Boscia albitrunca association; and 3) Baikiaea plurijuga – Terminalia sericea class with Pterocarpus angolensis–Diploryhnchus condylocarpon association, Dalbergia martinii–Berchemia discolor association, and Acacia fleckii–Baphia massaiensis association (Lushetile, 2009). |
| Description du design | The American version of the transect line method (Bibby et al., 2012; Sutherland, 1996) was used to assess the population density and community structure of birds occurring in the ranch. A transect of 10 km in length and 100 m width (50 m on each side) was designed along roads traversing the ranch. The transect was divided into four equal sections (fig. 2). Each section was 2.5 km in length, and was surveyed three times (03/09/2014. 07/03/2015, 29/04/2015), each time in the same direction. Counts were conducted by the same observer, in the mornings, and in calm and cloudless weather conditions. Dominance is expressed as the percentage of the total number of pairs of a given species in relation to the total number of all pairs of all species recorded. A dominant species is defined as that comprising 5% or more of all individuals of all species recorded, and a subdominant species is defined as that comprising 2-4.99%. All birds showing breeding (e.g. transporting nesting material, constructing nests, feeding chicks etc.) or territorial (e.g. singing males) behaviour were recorded. Special attention was paid to simultaneously singing males, as they were important in determining the number of occupied territories. Special care was taken not to count the same birds twice, as this could overestimate the number of territories. The number of breeding pairs was estimated for each section on each transect. The maximumnumber of breeding pairs at each survey and on each section was assumed as the real number of breeding pairs. The total number of breeding pairs of each species on a particular transect was calculated as the total of maximum numbers recorded on each section within the transect. The following guilds were distinguished: diet (G, granivorous; I, insectivorous; F, frugivorous; N, nectarivorous); and nesting (T, in trees or shrubs; H, in holes; G, on the ground; V, in herbaceous vegetation). The following indices were used to characterise diversity, evenness and similarity between the communities: 1) Shannon’s diversity index: H’ = -∑ pi ln pi where: pi is the proportion of breeding pairs belonging to the ith species 2) Simpson’s diversity index: D = ((∑n(n-1))/N(N-1) where: n – total number of breeding pairs belonging to a given species, N – total number of breeding pairs of all species 3) Pielou’s evenness index: J’ = (-∑ pi ln pi)/ln S where pi is the proportion of breeding pairs belonging to the ith species; S – total number of species. J’ varies between 0 and 1. The lower the variation between species in a community, the higher the J’. 4) Community dominance index: DI = (n1 + n2)/N where n1, n2 – number of pairs of the two most abundant species, N – total number of pairs of all species. 5) Sörensen’s Coefficient: I = 2C/A+B where A – the number of bird species in one plot, B – the number of bird species in another plot, C – the number of bird species common to both plots. Systematics and nomenclature of bird species follow Hockey et al. (2005). Scientific names of bird species are listed in appendix 1. |
Les personnes impliquées dans le projet:
Méthodes d'échantillonnage
The American version of the transect line method (Bibby et al., 2012; Sutherland, 1996) was used to assess the population density and community structure of birds occurring in the ranch. A transect of 10 km in length and 100 m width (50 m on each side) was designed along roads traversing the ranch. The transect was divided into four equal sections (fig. 2). Each section was 2.5 km in length, and was surveyed three times (03/09/2014. 07/03/2015, 29/04/2015), each time in the same direction. Counts were conducted by the same observer, in the mornings, and in calm and cloudless weather conditions. Dominance is expressed as the percentage of the total number of pairs of a given species in relation to the total number of all pairs of all species recorded. A dominant species is defined as that comprising 5% or more of all individuals of all species recorded, and a subdominant species is defined as that comprising 2-4.99%.
| Etendue de l'étude | The study was conducted in the Sachinga Livestock Development Centre of the Ministry of Agriculture of the Namibian Government. The centre is situated in NE Namibia, in the Zambezi region, about 40 km west of Katima Mulilo (fig. 1), between S17.39.40-S17.40.20 and E 24.23.55-E24.24.02. The Centre is a ranch of 3,243 ha. The aim of the centre is in situ conservation, livestock improvement programmes and provision of breeding animals to the farmers, and farmer education. The centre is surrounded by communal areas with subsistence farming. Most of the Sachinga LDC is covered by teak woodland, with smaller portion of Burkea-Kisat-False Mopane woodland and Omuramba grassland. The natural vegetation is well-preserved and represented by three classes of Kalahari woodland: 1) Colophospermum mopane , with two dominant associations: Nymphaea nouchali–Eragrostis rotifer which contains water species, and Combretum imberbe–Acacia nigrescens in association with sparse woodlands; 2) Baikiaea plurijuga woodland, comprising Guibourtia coleospherma–Burkea africana Association and Combretum collinum–Boscia albitrunca association; and 3) Baikiaea plurijuga – Terminalia sericea class with Pterocarpus angolensis–Diploryhnchus condylocarpon association, Dalbergia martinii–Berchemia discolor association, and Acacia fleckii–Baphia massaiensis association (Lushetile, 2009). |
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| Contrôle qualité | All birds showing breeding (e.g. transporting nesting material, constructing nests, feeding chicks etc.) or territorial (e.g. singing males) behaviour were recorded. Special attention was paid to simultaneously singing males, as they were important in determining the number of occupied territories. Special care was taken not to count the same birds twice, as this could overestimate the number of territories. The number of breeding pairs was estimated for each section on each transect. The maximumnumber of breeding pairs at each survey and on each section was assumed as the real number of breeding pairs. The total number of breeding pairs of each species on a particular transect was calculated as the total of maximum numbers recorded on each section within the transect. |
Description des étapes de la méthode:
- The following indices were used to characterise diversity, evenness and similarity between the communities: 1) Shannon’s diversity index: H’ = -∑ pi ln pi where: pi is the proportion of breeding pairs belonging to the ith species 2) Simpson’s diversity index: D = ((∑n(n-1))/N(N-1) where: n – total number of breeding pairs belonging to a given species, N – total number of breeding pairs of all species 3) Pielou’s evenness index: J’ = (-∑ pi ln pi)/ln S where pi is the proportion of breeding pairs belonging to the ith species; S – total number of species. J’ varies between 0 and 1. The lower the variation between species in a community, the higher the J’. 4) Community dominance index: DI = (n1 + n2)/N where n1, n2 – number of pairs of the two most abundant species, N – total number of pairs of all species. 5) Sörensen’s Coefficient: I = 2C/A+B where A – the number of bird species in one plot, B – the number of bird species in another plot, C – the number of bird species common to both plots. Systematics and nomenclature of bird species follow Hockey et al. (2005). Scientific names of bird species are listed in appendix 1.
Citations bibliographiques
- Kopij, G., 2020. Abundance and community structure of birds breeding in Kalahari woodland used as rangeland. Arxius de Miscel·lania Zoologica, 18: 101-112, Doi: https://doi.org/10.32800/amz.2020.18.0101 https://doi.org/10.32800/amz.2020.18.0101
Métadonnées additionnelles
| Identifiants alternatifs | 10.15470/rova7r |
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| 792a2342-1dbb-459b-84cd-e6eb1f9ba6c9 | |
| https://ipt.gbif.es/resource?r=birds_kalahari_woodland |