Mountain fens are vital ecosystems for habitat, biodiversity, water and carbon cycling, but there is little comprehensive information on their distribution, abundance or condition in any region of the western U.S. Our study objectives were to: 1) evaluate fen distribution, abundance and characteristics in the San Juan Mountains of Colorado, 2) quantify disturbances, and 3) prioritize restoration needs of fens. We mapped 624 fens in 37 watersheds and collected field data on 182 of these fens. We estimated that approximately 2,000 fens occur in the San Juan Mountains, primarily in the subalpine zone at an average elevation of 3,288 m. Fens ranged from 0.2 to 20.5 ha in size, peat thickness ranged between 0.40 to >4.00 m, and surface slope ranged from 0-21%. Groundwater pH ranged from 3.1-7.6 and Ca +2 from 1-341 mg/L, reflecting the diverse geochemistry of watershed parent materials. We identified 188 vascular and 63 bryophyte taxa, and classified the 309 sampled stands into 20 plant communities that formed along complex hydrogeomorphic and geochemical gradients. The majority of fens were in excellent condition; however 10% of our sampled fens had high to very high restoration potential due to impacts from roads, mining, and ditching.
There is a data gap in our current knowledge of the geospatial distribution, type and extent of C rich peatlands across the globe. The Pastaza Marañón Foreland Basin (PMFB), within the Peruvian Amazon, is known to store large amounts of peat, but the remoteness of the region makes field data collection and mapping the distribution of peatland ecotypes challenging. Here we review methods for developing high accuracy peatland maps for the PMFB using a combination of multi-temporal synthetic aperture radar (SAR) and optical remote sensing in a machine learning classifier. The new map produced has 95% overall accuracy with low errors of commission (1–6%) and errors of omission (0–15%) for individual peatland classes. We attribute this improvement in map accuracy over previous maps of the region to the inclusion of high and low water season SAR images which provides information about seasonal hydrological dynamics. The new multi-date map showed an increase in area of more than 200% for pole forest peatland (6% error) compared to previous maps, which had high errors for that ecotype (20–36%). Likewise, estimates of C stocks were 35% greater than previously reported (3.238 Pg in Draper et al. (2014) to 4.360 Pg in our study). Most of the increase is attributed to pole forest peatland which contributed 58% (2.551 Pg) of total C, followed by palm swamp (34%, 1.476 Pg). In an assessment of deforestation from 2010 to 2018 in the PMFB, we found 89% of the deforestation was in seasonally flooded forest and 43% of deforestation was occurring within 1 km of a river or road. Peatlands were found the least affected by deforestation and there was not a noticeable trend over time. With development of improved transportation routes and population pressures, future land use change is likely to put South American tropical peatlands at risk, making continued monitoring a necessity. Accurate mapping of peatland ecotypes with high resolution (<30 m) sensors linked with field data are needed to reduce uncertainties in estimates of the distribution of C stocks, and to aid in deforestation monitoring.
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