Functional and species composition of understory plants varies with mistletoe-infection on Vachellia karroo trees in a semi-arid African savanna

In savanna ecosystems, tree canopy patches differ in plant species composition compared to adjacent intercanopy spaces due to different levels of resource availabilities. Mistletoes further augment nutrients underneath tree canopies whilst reducing their hosts’ competitive edge, thus providing more...

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Autores principales: Tsitsi Sithandiwe Maponga, Hilton Garikai Taambuka Ndagurwa, Ed T.F. Witkowski
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Publicado: Elsevier 2021
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spelling oai:doaj.org-article:64401736480d43f88d304c700102bb092021-11-04T04:32:23ZFunctional and species composition of understory plants varies with mistletoe-infection on Vachellia karroo trees in a semi-arid African savanna2351-989410.1016/j.gecco.2021.e01897https://doaj.org/article/64401736480d43f88d304c700102bb092021-12-01T00:00:00Zhttp://www.sciencedirect.com/science/article/pii/S2351989421004479https://doaj.org/toc/2351-9894In savanna ecosystems, tree canopy patches differ in plant species composition compared to adjacent intercanopy spaces due to different levels of resource availabilities. Mistletoes further augment nutrients underneath tree canopies whilst reducing their hosts’ competitive edge, thus providing more resources and creating patches that support higher understory species richness. However, little is known on how understory species and functional trait assemblages, in both canopy and intercanopy spaces, are affected by varying overstory mistletoe infection intensities. This study investigated how functional and species diversity/composition varied within and between canopy patches and intercanopy spaces of high- and low mistletoe-infected Vachellia karroo trees. The affinity of individual species to the different canopy patches and intercanopy spaces was also assessed. Microhabitats had significantly different species compositions. A higher proportion of species (34%) showed a strong positive affinity towards canopy patches whilst intercanopy spaces were strongly associated with only 9% of recorded species, indicating greater dominance of some species there. Generally, subcanopy patches had significantly higher species richness and diversity, and functional diversity, compared to adjacent intercanopy spaces. These variables increased with increasing mistletoe infection, thus grass, forb and tree species diversity were 17–43% higher, and functional diversity indices were 0.5–28% greater in high- compared to low mistletoe-infection canopy patches. Furthermore, species richness and diversity of C3, C4, annual and perennial plants were 1.27–3.13-fold higher within canopy patches compared to intercanopy spaces and 1.28–1.74-fold greater within high- compared to low mistletoe-infection microhabitats. Consequently, high mistletoe-infection canopy patches had between 1.08 and 3.76-fold greater species richness and diversity of C3, C4, annual and perennial plants compared to the other three microhabitats. Our findings suggest that by enhancing spatial heterogeneity, variations in mistletoe infection facilitate biodiversity and to a lesser extent vegetation structural diversity in these semi-arid savannas.Tsitsi Sithandiwe MapongaHilton Garikai Taambuka NdagurwaEd T.F. WitkowskiElsevierarticleAffinityFunctional diversityHeterogeneityMistletoesSavannaSpecies diversityEcologyQH540-549.5ENGlobal Ecology and Conservation, Vol 32, Iss , Pp e01897- (2021)
institution DOAJ
collection DOAJ
language EN
topic Affinity
Functional diversity
Heterogeneity
Mistletoes
Savanna
Species diversity
Ecology
QH540-549.5
spellingShingle Affinity
Functional diversity
Heterogeneity
Mistletoes
Savanna
Species diversity
Ecology
QH540-549.5
Tsitsi Sithandiwe Maponga
Hilton Garikai Taambuka Ndagurwa
Ed T.F. Witkowski
Functional and species composition of understory plants varies with mistletoe-infection on Vachellia karroo trees in a semi-arid African savanna
description In savanna ecosystems, tree canopy patches differ in plant species composition compared to adjacent intercanopy spaces due to different levels of resource availabilities. Mistletoes further augment nutrients underneath tree canopies whilst reducing their hosts’ competitive edge, thus providing more resources and creating patches that support higher understory species richness. However, little is known on how understory species and functional trait assemblages, in both canopy and intercanopy spaces, are affected by varying overstory mistletoe infection intensities. This study investigated how functional and species diversity/composition varied within and between canopy patches and intercanopy spaces of high- and low mistletoe-infected Vachellia karroo trees. The affinity of individual species to the different canopy patches and intercanopy spaces was also assessed. Microhabitats had significantly different species compositions. A higher proportion of species (34%) showed a strong positive affinity towards canopy patches whilst intercanopy spaces were strongly associated with only 9% of recorded species, indicating greater dominance of some species there. Generally, subcanopy patches had significantly higher species richness and diversity, and functional diversity, compared to adjacent intercanopy spaces. These variables increased with increasing mistletoe infection, thus grass, forb and tree species diversity were 17–43% higher, and functional diversity indices were 0.5–28% greater in high- compared to low mistletoe-infection canopy patches. Furthermore, species richness and diversity of C3, C4, annual and perennial plants were 1.27–3.13-fold higher within canopy patches compared to intercanopy spaces and 1.28–1.74-fold greater within high- compared to low mistletoe-infection microhabitats. Consequently, high mistletoe-infection canopy patches had between 1.08 and 3.76-fold greater species richness and diversity of C3, C4, annual and perennial plants compared to the other three microhabitats. Our findings suggest that by enhancing spatial heterogeneity, variations in mistletoe infection facilitate biodiversity and to a lesser extent vegetation structural diversity in these semi-arid savannas.
format article
author Tsitsi Sithandiwe Maponga
Hilton Garikai Taambuka Ndagurwa
Ed T.F. Witkowski
author_facet Tsitsi Sithandiwe Maponga
Hilton Garikai Taambuka Ndagurwa
Ed T.F. Witkowski
author_sort Tsitsi Sithandiwe Maponga
title Functional and species composition of understory plants varies with mistletoe-infection on Vachellia karroo trees in a semi-arid African savanna
title_short Functional and species composition of understory plants varies with mistletoe-infection on Vachellia karroo trees in a semi-arid African savanna
title_full Functional and species composition of understory plants varies with mistletoe-infection on Vachellia karroo trees in a semi-arid African savanna
title_fullStr Functional and species composition of understory plants varies with mistletoe-infection on Vachellia karroo trees in a semi-arid African savanna
title_full_unstemmed Functional and species composition of understory plants varies with mistletoe-infection on Vachellia karroo trees in a semi-arid African savanna
title_sort functional and species composition of understory plants varies with mistletoe-infection on vachellia karroo trees in a semi-arid african savanna
publisher Elsevier
publishDate 2021
url https://doaj.org/article/64401736480d43f88d304c700102bb09
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