scholarly journals No Difference in Instream Decomposition Among Upland Agricultural and Forested Streams in Kenya

2021 ◽  
Vol 9 ◽  
Author(s):  
Ellen C. Kadeka ◽  
Frank O. Masese ◽  
David M. Lusega ◽  
Augustine Sitati ◽  
Benjamin N. Kondowe ◽  
...  
Keyword(s):  
Leaf Litter ◽  
Litter Decomposition ◽  
Agricultural Land ◽  
Leaf Litter Decomposition ◽  
Limited Data ◽  
Negative Effects ◽  
Decomposition Rates ◽  
Tropical Regions ◽  
Fine Mesh ◽  
Agricultural Streams

Expansion of agriculture is particularly worrying in tropical regions of the world, where native forests have been replaced by croplands and grasslands, with severe consequences for biodiversity conservation and ecosystem functioning. However, limited data exist on the effects of agriculture on the functioning of tropical streams. We conducted a leaf litter decomposition experiment in coarse- and fine-mesh litterbags using the three species of leaves (Eucalyptus globulus [non-native], Vernonia myriantha, and Syzygium cordatum [indigenous]) in three forested and agricultural streams to determine the effect of agriculture on instream leaf litter decomposition in headwater stream sites. We also examined the functional composition of macroinvertebrates in the streams through the contents of benthic kick samples. Agricultural streams had a less dense riparian canopy and smaller abundance of coarse organic particulate matter, and higher electric conductivity and suspended solids than forested streams. In terms of the effects of litter quality on decomposition rates, Vernonia had the fastest decomposition rates while Eucalyptus had the slowest in both forested and agricultural sites. Shredder invertebrates were less abundant in agricultural streams, and in both stream types, they were less diverse and abundant than other functional groups. Overall, leaf litter decomposition rates did not respond to agricultural land-use. The hypothesized negative effects of agriculture on organic matter processing were minimal and likely modulated by intact riparian zones along agricultural streams.

scholarly journals Effects of gamma irradiation on instream leaf litter decomposition

Hydrobiologia ◽  
2021 ◽  
Author(s):  
Luz Boyero ◽  
Naiara López-Rojo ◽  
Javier Pérez ◽  
Alan M. Tonin ◽  
Francisco Correa-Araneda ◽  
...  
Keyword(s):  
Gamma Irradiation ◽  
Leaf Litter ◽  
Litter Decomposition ◽  
Litter Quality ◽  
Leaf Litter Decomposition ◽  
Litter Chemistry ◽  
Decomposition Rates ◽  
Fine Mesh ◽  
And Control ◽  
Control Litter

AbstractLeaf litter decomposition is a key process in stream ecosystems, the rates of which can vary with changes in litter quality or its colonization by microorganisms. Decomposition in streams is increasingly used to compare ecosystem functioning globally, often requiring the distribution of litter across countries. It is important to understand whether litter sterilization, which is required by some countries, can alter the rates of decomposition and associated processes. We examined whether litter sterilization with gamma irradiation (25 kGy) influenced decomposition rates, litter stoichiometry, and colonization by invertebrates after weeks of instream incubation within coarse-mesh and fine-mesh litterbags. We used nine plant species from three families that varied widely in litter chemistry but found mostly consistent responses, with no differences in decomposition rates or numbers of invertebrates found at the end of the incubation period. However, litter stoichiometry differed between irradiated and control litter, with greater nutrient losses (mostly phosphorus) in the former. Therefore, the effects of irradiation on litter chemistry should be taken into account in studies focused on stoichiometry but not necessarily in those focused on decomposition rates, at least within the experimental timescale considered here.

scholarly journals Leaf litter decomposition rates increase with rising mean annual temperature in Hawaiian tropical montane wet forests

2014 ◽  
Author(s):  
Lori D Bothwell ◽  
Paul C Selmants ◽  
Christian P Giardina ◽  
Creighton M. Litton
Keyword(s):  
Leaf Litter ◽  
Litter Decomposition ◽  
Forest Ecosystems ◽  
Net Primary Productivity ◽  
Nutrient Release ◽  
Leaf Litter Decomposition ◽  
Mean Annual Temperature ◽  
Decomposition Rates ◽  
Litter Decay ◽  
Wet Forests

Decomposing litter in forest ecosystems supplies nutrients to plants, carbon to heterotrophic soil microorganisms and is a large source of CO2 to the atmosphere. Despite its essential role in carbon and nutrient cycling, the temperature sensitivity of leaf litter decay in tropical forest ecosystems remains poorly resolved, especially in tropical montane wet forests where the warming trend may be amplified compared to tropical wet forests at lower elevations. We quantified leaf litter decomposition rates along a highly constrained 5.2 °C mean annual temperature (MAT) gradient in tropical montane wet forests on the Island of Hawaii. Dominant vegetation, substrate type and age, soil moisture, and disturbance history are all nearly constant across this gradient, allowing us to isolate the effect of rising MAT on leaf litter decomposition and nutrient release. Leaf litter decomposition rates were a positive linear function of MAT, causing the residence time of leaf litter on the forest floor to decline by ~31 days for each 1 °C increase in MAT. Our estimate of the Q10 temperature coefficient for leaf litter decomposition was 2.17, within the commonly reported range for heterotrophic organic matter decomposition (1.5 – 2.5) across a broad range of ecosystems. The percentage of leaf litter nitrogen (N) remaining after six months declined linearly with increasing MAT from ~ 88% of initial N at the coolest site to ~74% at the warmest site. The lack of net N immobilization during all three litter collection periods at all MAT plots indicates that N was not limiting to leaf litter decomposition, regardless of temperature. These results suggest that leaf litter decay in tropical montane wet forests may be more sensitive to rising MAT than in tropical lowland wet forests, and that increased rates of N release from decomposing litter could delay or prevent progressive N limitation to net primary productivity with climate warming.

Litter dynamics in two Sierran mixed conifer forests. I. Litterfall and decomposition rates

1988 ◽  
Vol 18 (9) ◽  
pp. 1127-1135 ◽  
Author(s):  
Thomas J. Stohlgren
Keyword(s):  
Mass Loss ◽  
Leaf Litter ◽  
Litter Decomposition ◽  
Woody Debris ◽  
Leaf Litter Decomposition ◽  
Decomposition Rates ◽  
White Fir ◽  
Mixed Conifer Forests ◽  
Sugar Pine ◽  
Giant Sequoia

Litterfall was measured for 4 years and leaf litter decomposition rates were studied for 3.6 years in two mixed conifer forests (giant sequoia–fir and fir–pine) in the southern Sierra Nevada of California. The giant sequoia–fir forest (GS site) was dominated by giant sequoia (Sequoiadendrongiganteum (Lindl.) Buchh.), white fir (Abiesconcolor Lindl. & Gord.), and sugar pine (Pinuslambertiana Dougl.). The fir–pine forest (FP site) was dominated by white fir, sugar pine, and incense cedar (Calocedrusdecurrens (Torr.) Florin). Litterfall, including large woody debris <15.2 cm in diameter, at the GS site averaged 6364 kg•ha−1•year−1 compared with 4355 kg•ha−1•year−1 at the FP site. Compared with other temperate coniferous forests, annual variability in litterfall (as computed by the ratio of the annual maximum/minimum litterfall) was extremely high for the GS site (5.8:1) and moderately high for the FP site (3.4:1). In the GS site, leaf litter decomposition after 3.6 years was slowest for giant sequoia (28.2% mass loss), followed by sugar pine (34.3%) and white fir (45.1%). In the FP site, mass loss was slowest for sugar pine (40.0%), followed by white fir (45.1%), while incense cedar showed the greatest mass loss (56.9%) after 3.6 years. High litterfall rates of large woody debris (i.e., 2.5–15.2 cm diameter) and slow rates of leaf litter decomposition in the giant sequoia–fir forest type may result in higher litter accumulation rates than in the fir–pine type. Leaf litter times to 95% decay for the GS and FP sites were 30 and 27 years, respectively, if the initial 0.7-year period (a short period of rapid mass decay) was ignored in the calculation. A mass balance approach for total litterfall (<15.2 cm diameter) decomposition yielded lower decay constants than did the litterbag study and therefore longer times to 95% decay (57 years for the GS site and 62 years for the FP site).

scholarly journals Avaliação da Atividade Alimentar dos Invertebrados de Solo em Campos do Sul do Brasil – Bait-Lamina Test

2011 ◽  
Vol 4 (3) ◽  
pp. 108-113 ◽  
Author(s):  
Luciana Regina Podgaiski ◽  
Fernanda Schmidt Silveira ◽  
Milton Mendonça Jr.
Keyword(s):  
Leaf Litter ◽  
Litter Decomposition ◽  
Soil Fauna ◽  
Soil Depth ◽  
Feeding Activity ◽  
Soil Invertebrates ◽  
Leaf Litter Decomposition ◽  
The South ◽  
Decomposition Rates ◽  
Campos Sulinos

Esse trabalho tem como finalidade fornecer informações sobre um teste pioneiro (bait-lamina test) utilizado nos Campos do Sul do Brasil com a finalidade de avaliar a atividade alimentar dos invertebrados do solo – um indicativo de taxas de decomposição da serapilheira nos ecossistemas. Descreve-se o comportamento alimentar durante dois meses, acessando a profundidade do solo (0-8 cm) na qual ocorre maior consumo e analisando duas formas de quantificação deste consumo (técnica conservativa X técnica prática) em dois diferentes ecossistemas campestres. Foram estabelecidas 100 unidades amostrais (u.a.) independentemente em cada área (pastejada e não pastejada), adicionando a cada uma duas bait-lamina, uma disposta horizontalmente na superfície do solo, e outra verticalmente dentro do solo. Para cada data amostral (9, 16, 22, 29 e 65 dias de exposição) foram sorteadas 20 u.a. para análise. Foi observado grande consumo desde o início da exposição, tanto na superfície quanto dentro do solo. A atividade da fauna diferiu com a profundidade do solo, sendo maior na superfície e na profundidade de 6,5-8 cm. Em relação às diferentes técnicas, ambas revelaram resultados similares quando se compararam as duas áreas. A área pastejada demonstrou menor atividade dos invertebrados quando comparada a não pastejada. Esses resultados constituem base para futuras pesquisas no Brasil, relatando que o teste de bait-lamina nos Campos Sulinos pode oferecer resultados otimizados após cerca de uma quinzena de dias de exposição. Evaluation of Soil Invertebrates Feeding Activity in South Brazilian Campos – Bait Lamina Test Abstract. The aim of this work is to inform about a pioneer bait-lamina test in the South Brazilian Campos to evaluate the soil invertebrates feeding activity which is an approaching to leaf litter decomposition rates in the ecosystems. The feeding activity was tested during two months, across 8 cm of soil depth and employing a comparison between two techniques of consumption quantification (conservative technique vs. practical technique) in two different grassland areas (grazed and not grazed) were described. One hundred independent sampling units (s.u.) were established on each area, and in each s.u. two bait-lamina were inserted: one horizontally and another vertically. For each sampling date (9, 16, 22, 29 e 65 days of exposition), 20 s.u. were sorted and analyzed. We observed a high feeding activity from the beginning of the experiments, both in the surface and within the soil. Soil fauna feeding activity differed according to soil depth, being higher on the surface and for 6.5-8 cm deep in the soil. Both techniques lead to similar results when the two areas were compared. The grazed site showed lower invertebrate feeding activity than the site not grazed. These findings constitute a basis for future researches in Brazil, relating that the bait-lamina test can offer useful results around fifteen days of exposition.

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