An official website of the United States government
Stream bryophytes (mosses and liverworts) are widely recognized as important macroinvertebrate habitats, but their overall role in the stream ecosystem, particularly in nutrient cycling, remains understudied. Hubbard Brook Experimental Forest in New Hampshire, USA, contains some of the most extensively researched streams in the world, yet few studies mention their bryophytes. Perhaps this is because early estimates place bryophyte coverage in these streams at an insignificant 2%. However, data from 2019 show that contemporary coverage ranges from 4 to 40% among streams. To investigate how stream bryophyte cover may be changing over time and influencing stream nutrient stocks, we conducted field surveys, measured the mass of organic and inorganic bryophyte contents, and quantified nutrient uptake with bottle incubations of bryophyte mats. This study marks a novel attempt to map stream bryophyte coverage with estimates of C, P, and N stocks and fluxes. From our 2022 field surveys, we found that median bryophyte coverage varied across streams in the same catchment (0–41.4%) and shifted from just 3 y prior. We estimate that these bryophyte mats stored between 14 and 414 g of organic matter per m2 of stream in the form of live biomass and captured particulates. Within 12 h of light incubation, 35 out of 36 bryophyte clump samples sorbed peak historical water-column concentrations of PO43– as measured in the Hubbard Brook stream chemistry record. In Bear Brook, our scaled estimate of bryophyte mat NO3– uptake (2.3 g N/y) constitutes a substantial portion of previously estimated whole-stream NO3– uptake (12 g N/y). Cumulatively, our data demonstrate that bryophytes and their associated mineral substrates and biota—known as the bryosphere—are crucial in facilitating headwater stream nutrient cycling. These bryospheres may contribute significantly to interannual variability in stream nutrient concentrations within nutrient-poor streams, especially in climate-sensitive regions.
more »
« less
Hubbard Brook Experimental Forest: 2019 and 2022 Stream Bryophyte Abundance
Stream bryophytes (mosses and liverworts) are widely recognized as important macroinvertebrate habitats, but their overall role in the stream ecosystem, particularly in nutrient cycling, remains understudied. Hubbard Brook Experimental Forest contains some of the most extensively researched streams in the world, yet few studies mention their bryophytes. Perhaps this is because early estimates place stream bryophyte coverage at an insignificant 2%. However, data from 2019 show that contemporary coverage ranges from 4%–40% among streams. To investigate how stream bryophyte cover may be changing over time and influencing stream nutrient stocks, we conducted field surveys, measured organic and inorganic mass contents of bryophytes, and quantified nutrient uptake with bottle incubations of bryophyte mats. This study marks a novel attempt to map stream bryophyte coverage with estimates of carbon, phosphorus, and nitrogen stocks and fluxes. From our 2022 field surveys, we found that median bryophyte coverage can vary greatly across streams in the same catchment (0%–41.4%) and can also shift from just three years prior. We estimate that these bryophyte mats store between 14–414 g of organic matter per m2 of stream in the form of live biomass and captured particulates. Out of 36 bryophyte clump samples, 35 sorbed peak historical water column concentrations of PO43- measured within the Hubbard Brook stream chemistry record within 12 hours of light incubation. In Bear Brook, our scaled estimate of bryophyte mat nitrate uptake (2.3 g N y-1) constitutes a substantial portion of previously estimated whole-stream nitrate uptake (12 g N y-1). Cumulatively, our data demonstrates that bryophytes and their associated mineral substrates and biota—known as the bryosphere—are crucial in facilitating headwater stream nutrient cycling. These bryospheres may contribute significantly to interannual variability in stream nutrient concentrations within nutrient-poor streams, especially in climate-sensitive regions. These data were gathered as part of the Hubbard Brook Ecosystem Study (HBES). The HBES is a collaborative effort at the Hubbard Brook Experimental Forest, which is operated and maintained by the USDA Forest Service, Northern Research Station.
more »
« less
- PAR ID:
- 10572868
- Publisher / Repository:
- Environmental Data Initiative
- Date Published:
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
More Like this
-
-
This is the data and code associated with "Stream bryophytes promote 'cryptic' productivity in highly oligotrophic headwaters. Recent observations document increased abundance of algae in the headwater streams of Hubbard Brook Experimental Forest (HBEF). It is possible that this 'greening up' of HBEF streams may be due to climate change with rising temperatures, altered terrestrial phenology, and shifting hydrologic regimes. Alternatively, stream 'greening' could be due to the slow recovery of stream chemistry from decades of acid rain, which have led to rising stream water pH, declining concentrations of toxic Al3+, and extremely low solute concentrations. Three years of weekly algal measurements on contrasting substrates, 6 nutrient enrichment experiments reveal important new insights about the interactions between these two groups of autotrophs. We predicted that light availability, hydrologic disturbance and nutrient limitation were all important determinants of algal biomass in streams. To evaluate the relative strength and hierarchy of these limiting factors, we used nutrient diffusing substrates to investigate the role of nutrients for algae and compared algal accrual rate on artificial rock vs. moss substrates in stream channels vs. weir ponds to assess the role of hydrologic disturbance and scour. Our surveys and experiments spanned across seasons and local light regimes. Algal biomass was substantially higher in protected weir ponds than in stream channels, and in both habitats, algal biomass was substantially higher on artificial moss substrates than on tiles. Taken together, these results suggest that moss can provide physical protection from flood scour. Algal biomass instream on both substrate types was higher in high light seasons (pre-leaf out) and well-lit habitats indicating strong light limitation. Results from a series of 6 nutrient diffusing substrate experiments over the course of 2 years provided little evidence of nutrient limitation instream. The most striking finding of our investigation is the previously unsuspected role of stream bryophytes in providing critical refugia for algae in these steep, heavily shaded and oligotrophic headwaters. Shifts in stream productivity over time are likely to be closely tied to changes in bryophyte cover. These data were gathered as part of the Hubbard Brook Ecosystem Study (HBES). The HBES is a collaborative effort at the Hubbard Brook Experimental Forest, which is operated and maintained by the USDA Forest Service, Northern Research Station.more » « less
-
{"Abstract":["Detailed surveys of stream nitrate concentrations in the\n calcium-enriched (W1), hydrologic reference (W3), and biogeochemical\n reference (W6) watersheds were performed in the summer of 2015 with\n the goal of identifying "hotspots" of NO3- inflows into\n streams.\n\n \n Additional details on methods and analysis can be found at:\n\n \n Marinos, R. E., Campbell, J. L., Driscoll, C. T., Likens, G. E.,\n McDowell, W. H., Rosi, E. J., Rustad, L. E., & Bernhardt, E. S.\n (2018). Give and Take: A Watershed Acid Rain Mitigation Experiment\n Increases Baseflow Nitrogen Retention but Increases Stormflow Nitrogen\n Export. Environmental Science & Technology, 52(22), 13155\u201313165.\n https://doi.org/10.1021/acs.est.8b03553\n\n \n These data were gathered as part of the Hubbard Brook Ecosystem Study\n (HBES). The HBES is a collaborative effort at the Hubbard Brook\n Experimental Forest, which is operated and maintained by the US Forest\n Service, Northern Research Station."]}more » « less
-
This data set includes spatially explicit mark-recapture data of the Northern Spring Salamander (Gyrinophilus porphyriticus) collected via telemetry during the summer months (June – September) from 2019 - 2021 from eight reaches in multiple streams in the Hubbard Brook Experimental Forest. Salamanders were captured by hand and marked with PIT-tags. Telemetry surveys occurred weekly. These data were gathered as part of the Hubbard Brook Ecosystem Study (HBES). The HBES is a collaborative effort at the Hubbard Brook Experimental Forest, which is operated and maintained by the USDA Forest Service, Northern Research Station. These data are being used to publish the following papers: Cochrane, M. M., B. R. Addis, L. K. Swartz, and W. H. Lowe. 2023. Individual and population growth rates decline with watershed area in a stream salamander. In review Ecology. Cochrane, M. M., and W. H. Lowe. 2023. Floods increase downstream movement of adult and larval life stages of a headwater stream salamander. In prep Freshwater Biology.more » « less
-
We are conducting nutrient manipulations in three study sites in the White Mountain National Forest in New Hampshire: Bartlett Experimental Forest, Hubbard Brook Experimental Forest, and Jeffers Brook. We monitored foliar chemistry in 12 of our stands (excluding C3) pre-treatment (2008-2010) and post-treatment (2014-2016). In general, we found that foliar N concentrations were higher with N addition and foliar P concentrations were higher with P addition. More interestingly, P addition reduced foliar N concentrations and N addition reduced foliar P concentrations. Some interactive effects were observed (i.e. NxP, Species x N, Species x P, Species x N x P). This dataset contains pre- and post- treatment foliar chemistry data, and data from the analysis of quality control standard samples. These data were gathered as part of the Hubbard Brook Ecosystem Study (HBES). The HBES is a collaborative effort at the Hubbard Brook Experimental Forest, which is operated and maintained by the USDA Forest Service, Northern Research Station.more » « less
