Abundance and community structure of birds breeding in Kalahari woodland used as rangeland

Última versión Publicado por Museu de Ciències Naturals de Barcelona en Sep 9, 2020 Museu de Ciències Naturals de Barcelona

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.

Registros

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Los usuarios deben citar este trabajo de la siguiente manera:

Kopij, G., 2020. Abundance and community structure of birds breeding in Kalahari woodland used as rangeland. Museu de Ciències Naturals de Barcelona. Dataset/Occurrence:

Derechos

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El publicador y propietario de los derechos de este trabajo es Museu de Ciències Naturals de Barcelona. This work is licensed under a Creative Commons Attribution (CC-BY) 4.0 License.

Registro GBIF

Este recurso ha sido registrado en GBIF con el siguiente UUID: 792a2342-1dbb-459b-84cd-e6eb1f9ba6c9.  Museu de Ciències Naturals de Barcelona publica este recurso, y está registrado en GBIF como un publicador de datos avalado por GBIF Spain.

Palabras Clave

Community ecology; Population densities; Rangeland management; Occurrence

Contactos

¿Quién creó el recurso?:

G. Kopij
University of Namibia Oshakati NA

¿Quién puede resolver dudas acerca del recurso?:

G. Kopij
University of Namibia Oshakati NA

¿Quién documentó los metadatos?:

Montse Ferrer
Managing Editor
Arxius de Miscel·lània Zoològica, Museu de Ciències Naturals de Barcelona Pg Picasso s/n. 08003 Barcelona Barcelona ES

¿Quién más está asociado con el recurso?:

Proveedor de Contenido
Montse Ferrer
Managing Editor AMZ
Arxius de Miscel·lània Zoològica, Museu de Ciències Naturals de Barcelona Ps Picasso s/n 08003 Barcelona Barcelona

Cobertura Geográfica

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).

Coordenadas límite Latitud Mínima Longitud Mínima [-24.24, 17.39], Latitud Máxima Longitud Máxima [-24.23, 17.4]

Cobertura Taxonómica

No hay descripción disponible

Familia  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

Cobertura Temporal

Fecha Inicial / Fecha Final 2014-09-03 / 2015-04-29

Datos del Proyecto

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.

Título Abundance and community structure of birds breeding in Kalahari woodland used as rangeland
Descripción del Área de Estudio 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).
Descripción del Diseño 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.

Personas asociadas al proyecto:

Métodos de Muestreo

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%.

Área de Estudio 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).
Control de Calidad 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.

Descripción de la metodología paso a paso:

  1. 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.

Referencias Bibliográficas

  1. Kopij, G., 2020. Abundance and community structure of birds breeding in Kalahari woodland used as rangeland. Arxius de Miscel·lania Zoologica, 18: 101-112 https://doi.org/10.32800/ amz.2020.18.0101

Metadatos Adicionales

Identificadores Alternativos https://ipt.gbif.es/resource?r=birds_kalahari_woodland