Next Article in Journal
Can Deep Learning Extract Useful Information about Energy Dissipation and Effective Hydraulic Conductivity from Gridded Conductivity Fields?
Previous Article in Journal
Hydrodynamic Performance and Design Evolution of Wedge-Shaped Blocks for Dam Protection against Overtopping
Previous Article in Special Issue
Water Appropriation on the Agricultural Frontier in Western Bahia and Its Contribution to Streamflow Reduction: Revisiting the Debate in the Brazilian Cerrado
Article

Land Use Change Influences Ecosystem Function in Headwater Streams of the Lowland Amazon Basin

1
U.S. Geological Survey, Upper Midwest Environmental Sciences Center, La Crosse, WI 54601, USA
2
Woodwell Climate Research Center, Falmouth, MA 02540, USA
3
Instituto de Pesquisa Ambiental da Amazônia, Canarana 78640-000, Mato Grosso, Brazil
*
Author to whom correspondence should be addressed.
Academic Editor: Per-Erik Mellander
Water 2021, 13(12), 1667; https://doi.org/10.3390/w13121667
Received: 12 April 2021 / Revised: 17 May 2021 / Accepted: 25 May 2021 / Published: 15 June 2021
Intensive agriculture alters headwater streams, but our understanding of its effects is limited in tropical regions where rates of agricultural expansion and intensification are currently greatest. Riparian forest protections are an important conservation tool, but whether they provide adequate protection of stream function in these areas of rapid tropical agricultural development has not been well studied. To address these gaps, we conducted a study in the lowland Brazilian Amazon, an area undergoing rapid cropland expansion, to assess the effects of land use change on organic matter dynamics (OM), ecosystem metabolism, and nutrient concentrations and uptake (nitrate and phosphate) in 11 first order streams draining forested (n = 4) or cropland (n = 7) watersheds with intact riparian forests. We found that streams had similar terrestrial litter inputs, but OM biomass was lower in cropland streams. Gross primary productivity was low and not different between land uses, but ecosystem respiration and net ecosystem production showed greater seasonality in cropland streams. Although we found no difference in stream concentrations of dissolved nutrients, phosphate uptake exceeded nitrate uptake in all streams and was higher in cropland than forested streams. This indicates that streams will be more retentive of phosphorus than nitrogen and that if fertilizer nitrogen reaches streams, it will be exported in stream networks. Overall, we found relatively subtle differences in stream function, indicating that riparian buffers have thus far provided protection against major functional shifts seen in other systems. However, the changes we did observe were linked to watershed scale shifts in hydrology, water temperature, and light availability resulting from watershed deforestation. This has implications for the conservation of tens of thousands of stream kilometers across the expanding Amazon cropland region. View Full-Text
Keywords: headwater stream; agriculture; Amazon Basin; ecosystem metabolism; nutrient; organic matter; nitrogen; phosphorus headwater stream; agriculture; Amazon Basin; ecosystem metabolism; nutrient; organic matter; nitrogen; phosphorus
Show Figures

Figure 1

MDPI and ACS Style

Jankowski, K.J.; Deegan, L.A.; Neill, C.; Sullivan, H.L.; Ilha, P.; Maracahipes-Santos, L.; Marques, N.; Macedo, M.N. Land Use Change Influences Ecosystem Function in Headwater Streams of the Lowland Amazon Basin. Water 2021, 13, 1667. https://doi.org/10.3390/w13121667

AMA Style

Jankowski KJ, Deegan LA, Neill C, Sullivan HL, Ilha P, Maracahipes-Santos L, Marques N, Macedo MN. Land Use Change Influences Ecosystem Function in Headwater Streams of the Lowland Amazon Basin. Water. 2021; 13(12):1667. https://doi.org/10.3390/w13121667

Chicago/Turabian Style

Jankowski, Kathi J., Linda A. Deegan, Christopher Neill, Hillary L. Sullivan, Paulo Ilha, Leonardo Maracahipes-Santos, Nubia Marques, and Marcia N. Macedo 2021. "Land Use Change Influences Ecosystem Function in Headwater Streams of the Lowland Amazon Basin" Water 13, no. 12: 1667. https://doi.org/10.3390/w13121667

Find Other Styles
Note that from the first issue of 2016, MDPI journals use article numbers instead of page numbers. See further details here.

Article Access Map by Country/Region

1
Back to TopTop