Nest sites selection by sympatric cavity-nesting birds in miombo woodlands

Abstract

Deforestation and habitat fragmentation have long been known as drivers of wildlife depletion but information on their specific impacts on cavity-nesting birds in the miombo woodlands has been lacking. A comparative study of disturbed and undisturbed sites was conducted in miombo woodlands of Zambia to assess impacts of environmental stressors on birds. Foot patrols were employed to locate, identify and count host trees and cavities for cavity-nesting birds on twenty 200 m × 200 m sample plots. Undisturbed forests had three times more cavities (the nesting sites for birds), while there were 24.6% fewer abandoned cavities in undisturbed forests than in disturbed forests. The rate of cavity abandonment was about twice as high in human-dominated forests compared to undisturbed forests (61.3% c.f. 31.9%). Cavity-nesting birds preferred larger (> 36.0 cm diameter at breast height) and taller (> 5.0 m) trees for nest placement, especially in human-dominated forests. A number of cavity-nesting birds preferred Brachystegia spiciformis (zebrawood), Julbernadia paniculata (munsa), Parinari curatellifolia (mobola-plum) and Uapaca kirkiana (mahobohobo) as host trees to 14 other miombo tree species. Arnot’s Chat (Myrmecocichla arnoti) had a wider selection of host trees for cavity-nesting than the other 40 cavity-nesting birds in the study areas. Anthropogenic activities such as uncontrolled firewood collection, wild fires, logging, and land clearing for agriculture negatively influenced wood abundance and diversity, with potential implications for persistence of cavity-nesting birds. The negative impacts of anthropogenic activities could be counteracted by conservation strategies such as implementation of sound forest policies, integrative land use practices, sustainable livelihood security and stakeholders’ awareness of the need to safeguard forest-dependent avifauna.Conservation implications: This comparative study unravels specific anthropogenic impacts on the cavity-nesting birds in the miombo woodlands, which would be relevant for designing and implementing targeted biodiversity conservation interventions against negative local environmental values and attitudes that support rural development on the expense of conservation of biodiversity such as birds.

Avifauna in Relation to Habitat Disturbance in Wildlife Management Areas of the Ruvuma Miombo Ecosystem, Southern Tanzania

“…Suggesting that farmlands have reached maximum disturbance, as in lower farmlands heterogeneous vegetation offer foods and shelter for birds encouraging higher diversity and abundance [8]. Thus the granivores which are largely seed eaters such as the bronze mannikin, southern cordon-bleu, and red-billed quelea were dominant in farmlands than in other habitats because farmlands were rich in seed types vegetation, in line with the findings of others [12,26]. Furthermore, for similar reasons, the abundance of the granivores species was also higher in open miombo where grassland patches are dominant than in forest areas.…”

“…The richness and diversity imply a variety of taxa that exist in an area, many taxa should, therefore, survive in habitats that have a variety of favorable conditions and resources such as the presence of food, nesting areas, shade and water that might contribute to higher species richness and diversity. Therefore, low species diversity in the farmland might be contributed by the insufficient supply of food as well as insufficient cover for birds to hide against predators, lack of shade to hide from diurnal temperature [12,26] low food supply compared to forests and woodlands. Suggesting that farmlands have reached maximum disturbance, as in lower farmlands heterogeneous vegetation offer foods and shelter for birds encouraging higher diversity and abundance [8].…”

Selección de sitios de nidificación y efecto del hábitat en el éxito reproductivo de Colaptes campestris (Carpintero Campestre) y Colaptes melanochloros (Carpintero Real) (Aves: Picidae) en talares bonaerenses

“…Entre las características a seleccionar se destacan las dimensiones del árbol-nido y de los árboles que lo rodean, por ejemplo, la altura o el diámetro de los troncos y ramas laterales (Spiering y Knight 2005, Bonnot et al 2009). Se ha reportado que algunos carpinteros seleccionan este tipo de características como barreras para que los depredadores de nidos accedan a la cavidad (Spiering y Knight 2005, Nyrienda et al 2016. Por último, en una escala de análisis aún más pequeña, la construcción de cavidades por parte de los carpinteros depende de las características estructurales de la madera que constituye el árbol (Schepps et al 1999).…”

“…altura del árbol, DAP, cantidad de corteza y, especialmente, la densidad de madera). Como se mencionó más arriba, los árboles de pequeño porte podrían no estar funcionando como barreras efectivas para el acceso de los depredadores de nidos(Spiering y Knight 2005, Nyrienda et al 2016) y que por esta razón no sean seleccionados como árboles-nido. Alternativamente, en un escenario ideal, como la densidad de madera y la arquitectura del árbol (DAP y altura del árbol) son cruciales para la seguridad mecánica del árbol(Van Gelder et al 2006), podría ocurrir que los carpinteros elijan construir sus cavidades en árboles más fuertes y seguros, lo que permitiría que las cavidades duren más tiempo (ver tambiénOjeda et al 2007, Cockle et al 2017.…”

Selección de sitios de nidificación y efecto del hábitat en el éxito reproductivo de Colaptes campestris (Carpintero Campestre) y Colaptes melanochloros (Carpintero Real) (Aves: Picidae) en talares bonaerenses

“…altura del árbol, DAP, cantidad de corteza y, especialmente, la densidad de madera). Como se mencionó más arriba, los árboles de pequeño porte podrían no estar funcionando como barreras efectivas para el acceso de los depredadores de nidos(Spiering y Knight 2005, Nyrienda et al 2016) y que por esta razón no sean seleccionados como árboles-nido. Alternativamente, en un escenario ideal, como la densidad de madera y la arquitectura del árbol (DAP y altura del árbol) son…”