Leaf litter production and litter nutrient dynamics of invasive Acacia mearnsii and native tree species in riparian forests of the Fynbos biome, South Africa

Railoun, Moegamad Zaid; Simaika, John P.; Jacobs, Shayne M.

doi:10.1016/j.foreco.2021.119515

Cited by 10 publications

(14 citation statements)

References 63 publications

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“…However, effects of Acacia invasion were weaker on macroinvertebrates than on aquatic hyphomycetes since macroinvertebrate and shredder densities, and shredder family richness were similar between stream types. Although this was unexpected because macroinvertebrate density generally increases as benthic litter biomass increases (Graça et al., 2004; Negishi & Richardson, 2003; Richardson, 1991), other studies have also shown no differences in macroinvertebrate density in decomposing leaf litter between native and invaded streams (in the Fynbos biome; Railoun, 2018). In this study, lower densities would be expected in invaded streams, especially in autumn/winter when litterfall inputs were lower.…”

Section: Discussionmentioning

confidence: 94%

“…For instance, the invasion of riparian forests by nitrogen (N)‐fixing species can increase aquatic N concentrations (e.g., Atwood et al., 2010; Goldstein et al., 2009; Mineau et al., 2011; Stewart et al., 2019; Wiegner et al., 2013) and alter N cycles (Mineau et al., 2011; Stewart et al., 2019), especially in ecosystems where N‐fixers were formerly absent or present in low abundances. If N‐fixing species differ in patterns of deciduousness from dominant native species, they can also alter litterfall dynamics in the riparian vegetation (Mineau et al., 2012; Railoun et al., 2021). Such alterations may affect stream macroinvertebrate communities (Lowe et al., 2008) and food webs (Atwood et al., 2010).…”

Section: Introductionmentioning

confidence: 99%

“…Although the effects of Acacia invasion on terrestrial ecosystems are well known (reviewed by Le Maitre et al., 2011; Lorenzo & Rodríguez‐Echeverría, 2015; Souza‐Alonso et al., 2017), studies addressing their effects on stream communities and processes (e.g., leaf litter decomposition) are recent, few and restricted to the Fynbos biome in South Africa and deciduous forests in central Portugal (Lowe et al., 2008; Pereira et al., 2021; Pereira & Ferreira, 2021, 2022; Railoun, 2018; Railoun et al., 2021). The invasion of the Fynbos biome by Acacia mearnsii altered leaf litterfall dynamics and increased litterfall rates (Railoun et al., 2021), and changed macroinvertebrate communities through alterations in the abundance of functional feeding groups (Lowe et al., 2008), but did not affect macroinvertebrate density associated with decomposing leaf litter nor leaf litter decomposition rates in streams (Railoun, 2018). The invasion of deciduous forests, mostly with A. dealbata and to a lesser extent with A. melanoxylon , increased aquatic N concentrations, which stimulated microbial decomposer activity, promoting microbially‐mediated leaf litter decomposition in streams flowing through Acacia stands (Pereira et al., 2021; Pereira & Ferreira, 2022).…”

Section: Introductionmentioning

confidence: 99%

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Effects of Acacia invasion on water quality, litterfall, aquatic decomposers, and leaf litter decomposition in streams

Pereira,

Figueiredo,

Coimbra

et al. 2024

Freshwater Biology

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Small streams and their riparian vegetation are closely linked ecosystems. Thus, the invasion of native riparian forests with non‐native species can impact stream ecosystems. We assessed the effects of the invasion of broadleaf deciduous forests by evergreen, nitrogen‐fixing Acacia species on seasonal variation of relevant instream environmental variables, litterfall in the riparian area, aquatic decomposers, and leaf litter decomposition, by comparing three streams flowing through native forests (native streams) and three streams flowing through invaded forests (invaded streams) in central Portugal. Invaded streams flow through forests composed (almost) of monospecific stands of Acacia trees. Litterfall in the riparian area was sampled with fabric traps and sorted into five categories: leaf (including phyllodes), flower, fruit and seed, wood litter, and other materials. Aquatic hyphomycete conidia suspended in water were sampled to assess conidia concentration and community composition. Leaf litter of Quercus robur was enclosed in coarse‐mesh bags and incubated in streams to assess decomposition rates and associated macroinvertebrate density and community composition. Samples from each variable were collected monthly from streams over 1 year. Aquatic hyphomycete conidia concentration was higher in invaded streams in spring/summer when litter inputs, water temperature, and aquatic nutrient concentrations were higher. In contrast, conidia concentration was lower in invaded streams in autumn/winter as they received less native deciduous leaf litter in autumn than native streams. Aquatic hyphomycete community structure changed, and species richness was lower in invaded streams because aquatic nutrient concentrations were higher and leaf litter species richness was lower. Macroinvertebrate and shredder density in decomposing leaf litter did not differ between native and invaded streams, but litter bags may have artificially increased densities by providing high quality food and/or refuges in streams with poor‐quality resources. Nevertheless, macroinvertebrate community structure changed, and family richness was lower in invaded streams. Finally, decomposition rates of Q. robur leaf litter in coarse‐mesh bags were similar between stream types, despite differences in aquatic decomposer communities. Overall, Acacia invasion changed water quality, litterfall seasonality and composition, and aquatic decomposer communities (especially aquatic hyphomycetes). However, Acacia effects on macroinvertebrate density and leaf litter decomposition rates were less pronounced, suggesting that higher trophic levels may be more resilient to invasion than basal levels, or the invasion time/extent in our invaded streams was not strong enough to affect macroinvertebrates and associated processes. Instream invasion effects on aquatic hyphomycete communities were more strongly mediated by changes in litter inputs rather than increases in aquatic nutrient concentrations because they remained oligotrophic in invaded streams. Simplification of riparian and aquatic communities may render them less efficient in coping with additional environmental changes. Acacia effects might be mitigated by the maintenance of a riparian corridor composed of native vegetation. The protection of non‐invaded riparian galleries and restoration of invaded ones could protect and restore stream ecosystems.

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Section: Discussionmentioning

confidence: 94%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Effects of Acacia invasion on water quality, litterfall, aquatic decomposers, and leaf litter decomposition in streams

Pereira,

Figueiredo,

Coimbra

et al. 2024

Freshwater Biology

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“…This insect-host association has been previously reported in Brazil, where an infestation rate of 44.3% was observed (Oliveira and Costa 2009), and South Africa (Rink 2013). Acacia mearnsii is cultivated in Brazil for tannins, cellulose, and charcoal production (Garlet et al 2011), whereas in Europe and in South Africa, presently, this species has a lower significant economic importance and is rather invasive (Souza-Alonso et al 2017;Railoun et al 2021).…”

Section: Discussionmentioning

confidence: 99%

Establishment and new hosts of the non-native seed beetle Stator limbatus (Coleoptera, Chrysomelidae, Bruchinae) on acacias in Europe

Cocco¹,

Brundu²,

Berquier³

et al. 2021

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Stator limbatus is a phytophagous beetle native to warm regions of North and Central America, feeding on Fabaceae seeds and one of the most polyphagous species within the subfamily Bruchinae, here reported for the first time in Europe and on new hosts. Adult beetles emerged from Acacia spp. seeds collected in the islands of Corsica (France), and Sardinia (Italy). The wide presence in Sardinia and Corsica supports the hypothesis that this alien species was introduced several years ago. In both islands, S. limbatus emerged from Acacia mearnsii seeds, with infestation rates of up to 74.2 and 90.8% in 2019 and 2020, respectively. This seed beetle also emerged from two previously unreported host species, Acacia saligna and A. pycnantha, showing highest infestation rates of 4.0 and 95.1%, respectively. Both Acacia species are reported as new host associations with S. limbatus. Overall, seed infestation rates recorded in 2019 and 2020 indicate that S. limbatus is well established and that Mediterranean bioclimatic conditions are suitable for its population increase in size. This study lays the foundations for further research on known and potential host species and the spread and distribution of S. limbatus in Europe.

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“…In addition to variation across the season and across different forest types, litterfall is also variable among years as a result of variation in climatic conditions (e.g., wind and snow) and forest age. As global climate change continues, studies on the within and among year variation in litterfall, and its role in nutrient cycling, will provide important baseline knowledge for understanding how these will change in the future [ 13 , 14 , 15 , 16 ].…”

Section: Introductionmentioning

confidence: 99%

Temporal Changes in Litterfall and Nutrient Cycling from 2005–2015 in an Evergreen Broad-Leaved Forest in the Ailao Mountains, China

Dai

Wei

Tang

et al. 2023

Plants

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The study of litter can provide an important reference for understanding patterns of forest nutrient cycling and sustainable management. Here, we measured litterfall (leaves, branches, etc.) from a wet, evergreen, broad-leaved forest in Ailao Mountains of southwestern China on a monthly basis for 11 years (2005–2015). We measured the total biomass of litter fall as well as its components, and estimated the amount of C, N, P, K, S, Ca, and Mg in the amount of litterfall. We found that: The total litter of evergreen, broadleaved forest in Ailao Mountains from 2005 to 2015 was 7.70–9.46 t/ha, and the output of litterfall differed between years. This provides a safeguard for the soil fertility and biodiversity of the area. The total amount of litterfall and its components showed obvious seasonal variation, with most showing a bimodal pattern (peak from March to May and October to November). The majority of litterfall came from leaves, and the total amount as well as its components were correlated with meteorological factors (wind speed, temperate and precipitation) as well as extreme weather events. We found that among years, the nutrient concentration was sorted as C > Ca > N > K > Mg > S > P. The nutrient concentration in the fallen litter and the amount of nutrients returned showed a decreasing trend, but the decreasing rate was slowed through time. Nutrient cycling was influenced by meteorological factors, such as temperature, precipitation, and wind speed, but the nutrient utilization efficiency is high, the circulation capacity is strong, and the turnover time is short. Our results showed that although there was nutrient loss in this evergreen, broad-leaved forest, the presence of forest litterfall can effectively curb potential ecological problems in the area.

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Leaf litter production and litter nutrient dynamics of invasive Acacia mearnsii and native tree species in riparian forests of the Fynbos biome, South Africa

Cited by 10 publications

References 63 publications

Effects of Acacia invasion on water quality, litterfall, aquatic decomposers, and leaf litter decomposition in streams

Effects of Acacia invasion on water quality, litterfall, aquatic decomposers, and leaf litter decomposition in streams

Establishment and new hosts of the non-native seed beetle Stator limbatus (Coleoptera, Chrysomelidae, Bruchinae) on acacias in Europe

Temporal Changes in Litterfall and Nutrient Cycling from 2005–2015 in an Evergreen Broad-Leaved Forest in the Ailao Mountains, China

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Leaf litter production and litter nutrient dynamics of invasive Acacia mearnsii and native tree species in riparian forests of the Fynbos biome, South Africa

Cited by 10 publications

References 63 publications

Effects of Acacia invasion on water quality, litterfall, aquatic decomposers, and leaf litter decomposition in streams

Effects of Acacia invasion on water quality, litterfall, aquatic decomposers, and leaf litter decomposition in streams

﻿Establishment and new hosts of the non-native seed beetle Stator limbatus (Coleoptera, Chrysomelidae, Bruchinae) on acacias in Europe

Temporal Changes in Litterfall and Nutrient Cycling from 2005–2015 in an Evergreen Broad-Leaved Forest in the Ailao Mountains, China

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Product

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Establishment and new hosts of the non-native seed beetle Stator limbatus (Coleoptera, Chrysomelidae, Bruchinae) on acacias in Europe