Effects of selective timber harvest on amphibian species diversity in Budongo forest Reserve, Uganda

Lukwago, Wilber; Behangana, Mathias; Mwavu, Edward N.; Hughes, Daniel F.

doi:10.1016/j.foreco.2019.117809

Cited by 7 publications

(5 citation statements)

References 56 publications

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“…These results seemingly align with the proposed multiple element limitation concept, which suggests a strong response in microbial mediated processes upon the supply of limiting nutrients (Fanin et al, 2015). Furthermore, the results likely indicate that some soil respiration sources may respond positively to N addition (Yan et al, 2017), while others may respond positively to P addition (Ma et al, 2020), yielding an overall additive response when added together. An increase in soil CO 2 effluxes following the simultaneous addition of N and P has also been reported in studies like Bréchet et al (2019), andSoong et al (2018) from Panamanian tropical forests.…”

Section: Discussionsupporting

confidence: 83%

“…The long-term mean annual temperature and precipitation over the study area is 25 • C and 1700 mm, respectively (Lukwago et al, 2020). Rainfall is distributed into two rainy seasons (i.e., March to May and August to November) punctuated by a strong dry season (December to February) and a weak dry season (June to July; Lukwago et al, 2020).…”

Section: Study Site Descriptionmentioning

confidence: 99%

“…The forest reserve spans over 825 km 2 and is extensively diverse with respect to forest communities, with Cynometra alexandri, Chrysophyllum albidum, Maesopsis eminii, and Diospyros abyssinica as the dominant tree species (Eggeling, 1947). The long-term mean annual temperature and precipitation over the study area is 25 • C and 1700 mm, respectively (Lukwago et al, 2020). Rainfall is distributed into two rainy seasons (i.e., March to May and August to November) punctuated by a strong dry season (December to February) and a weak dry season (June to July; Lukwago et al, 2020).…”

Section: Study Site Descriptionmentioning

confidence: 99%

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Nutrient limitations regulate soil greenhouse gas fluxes from tropical forests: evidence from an ecosystem-scale nutrient manipulation experiment in Uganda

Tamale

Hüppi

Griepentrog

et al. 2021

SOIL

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Abstract. Soil macronutrient availability is one of the abiotic controls that alters the exchange of greenhouse gases (GHGs) between the soil and the atmosphere in tropical forests. However, evidence on the macronutrient regulation of soil GHG fluxes from central African tropical forests is still lacking, limiting our understanding of how these biomes could respond to potential future increases in nitrogen (N) and phosphorus (P) deposition. The aim of this study was to disentangle the regulation effect of soil nutrients on soil GHG fluxes from a Ugandan tropical forest reserve in the context of increasing N and P deposition. Therefore, a large-scale nutrient manipulation experiment (NME), based on 40 m×40 m plots with different nutrient addition treatments (N, P, N + P, and control), was established in the Budongo Central Forest Reserve. Soil carbon dioxide (CO2), methane (CH4), and nitrous oxide (N2O) fluxes were measured monthly, using permanently installed static chambers, for 14 months. Total soil CO2 fluxes were partitioned into autotrophic and heterotrophic components through a root trenching treatment. In addition, soil temperature, soil water content, and nitrates were measured in parallel to GHG fluxes. N addition (N and N + P) resulted in significantly higher N2O fluxes in the transitory phase (0–28 d after fertilization; p<0.01) because N fertilization likely increased soil N beyond the microbial immobilization and plant nutritional demands, leaving the excess to be nitrified or denitrified. Prolonged N fertilization, however, did not elicit a significant response in background (measured more than 28 d after fertilization) N2O fluxes. P fertilization marginally and significantly increased transitory (p=0.05) and background (p=0.01) CH4 consumption, probably because it enhanced methanotrophic activity. The addition of N and P (N + P) resulted in larger CO2 fluxes in the transitory phase (p=0.01), suggesting a possible co-limitation of both N and P on soil respiration. Heterotrophic (microbial) CO2 effluxes were significantly higher than the autotrophic (root) CO2 effluxes (p<0.01) across all treatment plots, with microbes contributing about two-thirds of the total soil CO2 effluxes. However, neither heterotrophic nor autotrophic respiration significantly differed between treatments. The results from this study suggest that the feedback of tropical forests to the global soil GHG budget could be disproportionately altered by increases in N and P availability over these biomes.

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Section: Discussionsupporting

confidence: 83%

Section: Study Site Descriptionmentioning

confidence: 99%

Section: Study Site Descriptionmentioning

confidence: 99%

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Nutrient limitations regulate soil greenhouse gas fluxes from tropical forests: evidence from an ecosystem-scale nutrient manipulation experiment in Uganda

Tamale

Hüppi

Griepentrog

et al. 2021

SOIL

View full text Add to dashboard Cite

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“…The mean annual rainfall over the study region is about 1700 mm and is distributed in two wet seasons (March to May and August to November) separated by an extended dry season between December and February and a short dry season in June and July (Lukwago et al., 2020). The mean annual temperature is approximately 25°C.…”

Section: Methodsmentioning

confidence: 99%

Impact of urea fertilization rates on nitrogen losses, productivity and profitability in East African sugarcane plantations

Tamale,

Nasta,

Doetterl

et al. 2024

Soil Use and Management

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Fertilizer‐intensive sugarcane plantations are expanding in sub‐Saharan Africa (SSA) amidst increased groundwater pollution and carbon footprint concerns. Yet, the impact of nitrogen (N) levels on N losses, productivity and profitability in these plantations remains unclear. To address this gap, we conducted a completely randomized design experiment in a Ugandan sugarcane plantation using three N fertilization rates (low, standard and high) as treatments. N leaching under the different treatments was determined using the average drainage fluxes across a 1‐m‐layered profile which we estimated with a suite of pedotransfer functions (PTFs) and leachate N concentrations from suction cup lysimeters. Soil nitrous oxide fluxes were determined using static vented chamber bases and gas chromatography. Partial factor crop productivity was estimated from the average field fresh weight under each treatment and the amount of N fertilizer applied, while the return on investment was determined from the factory price of the field fresh weight and the market price of fertilizers. Our findings indicate that three out of five PTFs effectively estimated soil hydraulic properties at our test site, based on the close match between measured and predicted soil matric potential values. Notably, N leaching at low and standard N rates were comparable but significantly lower than at higher‐than‐standard N rates. Additionally, we measured comparable soil nitrous oxide emissions and field fresh weight but partial factor productivity and return on investment declined along the fertilizer intensification gradient. In conclusion, the study demonstrates the promising application of certain PTFs in N‐leaching modelling in the data‐scarce SSA. Furthermore, obtaining comparable field fresh weight with minimal N losses at lower‐than‐standard N rates presents an opportunity to mitigate groundwater pollution and greenhouse gas emissions. However, the potential impact of the switch from standard to low N rates on soil organic carbon stocks and sugarcane yields warrants further investigation.

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“…The study area receives about 1360 mm of rainfall annually (Climate-Data.org, 2020) distributed into two rainy seasons (i.e. March to May and August to November), a strong dry season (December to February), and a weak dry season (June to July) (Lukwago et al, 2020). It is worth noting that the amount of rainfall received during the field campaign (2385 mm, Fig.…”

mentioning

confidence: 99%

Nutrient limitations regulate soil greenhouse gas fluxes from tropical forests: evidence from an ecosystem-scale nutrient manipulation experiment in Uganda

Tamale¹,

Hüppi²,

Griepentrog³

et al. 2021

Preprint

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Abstract. Tropical forests contribute significantly to the emission and uptake of carbon dioxide (CO2), methane (CH4), and nitrous oxide (N2O). However, studies on the soil environmental controls of greenhouse gases (GHGs) from African tropical forest ecosystems are still rare. The aim of this study was to disentangle the regulation effect of soil nutrients on soil GHG fluxes in a tropical forest in northwestern Uganda. Therefore, a large-scale nutrient manipulation experiment (NME) based on 40 m × 40 m plots with different nutrient addition treatments (nitrogen (N), phosphorus (P), N + P, and control) was established. Soil CO2, CH4, and N2O fluxes were measured monthly using permanently installed static chambers for 14 months. Total soil CO2 fluxes were partitioned into autotrophic and heterotrophic components through a root trenching treatment. In addition, soil temperature, soil water content, and mineral N were measured in parallel to GHG fluxes. N addition (N, N + P) resulted in significantly higher N2O fluxes in the transitory phase (0–28 days after fertilization, p

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Effects of selective timber harvest on amphibian species diversity in Budongo forest Reserve, Uganda

Cited by 7 publications

References 56 publications

Nutrient limitations regulate soil greenhouse gas fluxes from tropical forests: evidence from an ecosystem-scale nutrient manipulation experiment in Uganda

Nutrient limitations regulate soil greenhouse gas fluxes from tropical forests: evidence from an ecosystem-scale nutrient manipulation experiment in Uganda

Impact of urea fertilization rates on nitrogen losses, productivity and profitability in East African sugarcane plantations

Nutrient limitations regulate soil greenhouse gas fluxes from tropical forests: evidence from an ecosystem-scale nutrient manipulation experiment in Uganda

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