Insectivorous birds are known to play a decisive role for the natural control of herbivorous insects. Thus, they enhance the growth, reproduction, and survival of plant individuals and in the long‐term benefit plant regeneration. However, particularly in the tropics, forest fragmentation has been suggested to cause a loss of insectivorous birds. Yet, it is unclear whether this hampers the trophic control of herbivorous insects with potential consequences for plants. Therefore, we investigated the effect of increasing forest fragmentation on tritrophic interactions between insectivorous birds, herbivorous insects, and plants in a subtropical forest landscape, South Africa. We monitored the community composition of birds and estimated insectivorous bird abundances along a gradient of forest fragmentation. In the same sites, we installed bird exclosures on a common plant species (Englerophytum natalense) to assess effects of the trophic control of insectivorous birds on herbivorous insects and leaf area loss (LAL). Forest fragmentation strongly shaped the functional composition of bird communities, particularly through a loss of forest‐dependent insectivorous birds. Moreover, LAL was higher within bird exclosures than on control branches and increased with increasing forest fragmentation on the control branches. Altogether, forest fragmentation seems to hamper the trophic control of herbivorous insects by insectivorous birds through changes in the community composition. This, in turn, may interfere with tritrophic interactions and ecological processes. Thus, conservation efforts aiming at enhancing the natural control of herbivorous insects should focus on the maintenance of continuous indigenous forests that are well‐connected to smaller forest fragments on the landscape scale.

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Eastern mistbelt forests are naturally fragmented forests with grassland which occur from the Eastern Cape to KwaZulu-Natal, South Africa. These were heavily logged by colonial settlers and continue to be harvested despite being protected. Consequently we documented a checklist of the plants of the forests and grasslands in the Weza district (3029DA WEZA), southern KwaZulu-Natal, including Ngeli Forest and nearby indigenous forest patches to highlight their biodiversity status and need for conservation. We also reviewed their status in the Red Data List. Of the 1554 records included in this summary of plant species for the Weza district, there were 6 lichens (0.4%), 46 bryophytes (3.0%), 58 pteridophytes (3.7%), 6 gymnosperms (0.4%) and the remaining 1424 species angiosperms (92.5%). Of the angiosperms, 27.3% were monocotyledons and 72.7% were dicotyledons. The most species-rich family was Asteraceae (239 species) followed by Fabaceae (115 species), Liliaceae (used for purposes of comparison against older studies – 89 species), Orchidaceae (89 species), Iridaceae (59 species), Poaceae (58 species), Asclepidaceae (again used for purposes of comparison against older studies – 57 species), Scrophulariaceae (42 species), Euphorbiaceae (32 species), Lamiaceae (32 species) and Rubiaceae (27 species). These 10 families each comprised more than 2% of the species in the list. Together they contributed 55% of the angiosperm species and 34.1% of the angiosperm genera. The biodiversity and conservation value of the study area are conserved pockets of eastern mistbelt forest, Drakensberg foothill moist grassland and mistbelt grassland. More than 4% of the species are under some degree of threat, as was evidenced by the number of species regarded as endangered (5), vulnerable (18), near threatened (10), critically rare (1), rare (20) or declining (11) amongst the 1554 species covered in the list.Conservation implications: In terms of taxa under some degree of threat, number of endemic and near endemic species the biodiversity and conservation value of the Ngele (3029DA WEZA) area is reinforced. This necessitates that the area is appropriately protected from invasive alien species, and uncontrolled and illegal use by the neighbouring communities.

No abstract

Eastern mistbelt forests are naturally fragmented forests with grassland which occur from the Eastern Cape to KwaZulu-Natal, South Africa. These were heavily logged by colonial settlers and continue to be harvested despite being protected. Consequently we documented a checklist of the plants of the forests and grasslands in the Weza district (3029DA WEZA), southern KwaZulu-Natal, including Ngeli Forest and nearby indigenous forest patches to highlight their biodiversity status and need for conservation. We also reviewed their status in the Red Data List. Of the 1554 records included in this summary of plant species for the Weza district, there were 6 lichens (0.4%), 46 bryophytes (3.0%), 58 pteridophytes (3.7%), 6 gymnosperms (0.4%) and the remaining 1424 species angiosperms (92.5%). Of the angiosperms, 27.3% were monocotyledons and 72.7% were dicotyledons. The most species-rich family was Asteraceae (239 species) followed by Fabaceae (115 species), Liliaceae (used for purposes of comparison against older studies – 89 species), Orchidaceae (89 species), Iridaceae (59 species), Poaceae (58 species), Asclepidaceae (again used for purposes of comparison against older studies – 57 species), Scrophulariaceae (42 species), Euphorbiaceae (32 species), Lamiaceae (32 species) and Rubiaceae (27 species). These 10 families each comprised more than 2% of the species in the list. Together they contributed 55% of the angiosperm species and 34.1% of the angiosperm genera. The biodiversity and conservation value of the study area are conserved pockets of eastern mistbelt forest, Drakensberg foothill moist grassland and mistbelt grassland. More than 4% of the species are under some degree of threat, as was evidenced by the number of species regarded as endangered (5), vulnerable (18), near threatened (10), critically rare (1), rare (20) or declining (11) amongst the 1554 species covered in the list.Conservation implications: In terms of taxa under some degree of threat, number of endemic and near endemic species the biodiversity and conservation value of the Ngele (3029DA WEZA) area is reinforced. This necessitates that the area is appropriately protected from invasive alien species, and uncontrolled and illegal use by the neighbouring communities.