02612nas a2200169 4500008004100000245010100041210006900142300001600211490000700227520203500234100001702269700001802286700001702304700002202321700001802343856008102361 2016 eng d00aA before-and-after assessment of patch-burn grazing and riparian fencing along headwater streams0 abeforeandafter assessment of patchburn grazing and riparian fenc a1543–15530 v533 a
  1. Fire and grazing are common in grasslands world-wide to maintain grass cover and cattle production. The effects of fire, cattle grazing and riparian fencing efficacy on prairie stream ecology are not well characterized at catchment scales.
  2. We examined alterations to stream water quality and biology from patch-burn grazing (PBG) in tallgrass prairie during a five-year, replicated, catchment scale experiment that used a Before-After/Control-Impact (BACI) design and was analysed by mixed-effects models. Treatments included two patch-burned control catchments (fire but no grazers) and PBG in two riparian-fenced and two unfenced catchments. We assessed the effectiveness of riparian fencing for mitigating potential water quality impacts by monitoring water quality and riparian usage by cattle via Global Positioning System.
  3. Riparian fences effectively excluded cattle; however, in unfenced pastures, cattle aggregated along streams 10–20% of the grazing season.
  4. After initiation of PBG, we detected large increases in some nutrients, Escherichia coli, algal biomass, primary productivity and community respiration in all catchments with PBG. Some water quality variables, such as E. coli concentrations, recovered quickly after cattle were removed from pasture, which indicated resiliency.
  5. Riparian fencing moderately reduced the impacts to stream variables, indicating either overland flow and/or subsurface flow allowed nutrients and bacteria to enter the streams.
  6. Synthesis and applications. Patch-burn grazing is a measurable disturbance that can alter the ecological condition of streams. Riparian fencing lessened the degree of impact, yet some water quality variables still exceeded regional reference conditions. Managers will need to assess the costs of riparian fencing compared to the moderate benefits that fencing provides to water quality.
1 aLarson, D.M.1 aDodds, W., K.1 aWhiles, M.R.1 aThompson, T.R., .1 aFulgoni, J.N. uhttps://besjournals.onlinelibrary.wiley.com/doi/full/10.1111/1365-2664.1269202956nas a2200313 4500008004100000245012400041210006900165300001400234490000700248520203700255100001802292700001702310700001802327700001702345700001502362700001802377700001602395700001402411700001702425700001702442700001502459700001902474700001902493700001902512700001402531700001802545700001702563856006202580 2015 eng d00aLong-term changes in structure and function of a tropical headwater stream following a disease-driven amphibian decline0 aLongterm changes in structure and function of a tropical headwat a575 - 5890 v603 a

1. Taxonomic and functional diversity in freshwater habitats is rapidly declining, but we know little about how such declines will ultimately affect ecosystems. Neotropical streams are currently experiencing massive losses of amphibians, with many losses linked to the chytrid fungus, Batrachochytrium dendrobatidis (Bd). 2. We examined the ecological consequences of the disease-driven loss of amphibians from a Panamanian stream. We quantified basal resources, macroinvertebrates, N uptake and fluxes through food-web components and ecosystem metabolism in 2012 and 2014 and compared them to pre-decline (2006) and 2 year post-decline (2008) values from a prior study. 3. Epilithon biomass accrued after the decline, more than doubling between 2006 and 2012, but then decreased fivefold from 2012 to 2014. In contrast, suspended particulate organic matter (SPOM) concentrations declined continuously after the amphibian decline through 2014. 4. Biomass of filter-feeding, grazing and shredding macroinvertebrates decreased from 2006 to 2014, while collector–gatherers increased during the same time period. Macroinvertebrate taxa richness decreased from 2006 (52 taxa) to 2012 (30 taxa), with a subsequent increase to 51 taxa in 2014. 5. Community respiration, which initially decreased after the amphibian decline, remained lower than pre-decline in 2012 but was greater than pre-decline values in 2014. Gross primary production remained low and similar among years, while inline image uptake length in both 2012 and 2014 was longer than pre-decline. Nitrogen flux to epilithon increased after the decline and continued to do so through 2014, but N fluxes to fine particulate organic matter and SPOM decreased and remained low. 6. Our findings underscore the importance of studying the ecological consequences of declining biodiversity in natural systems over relatively long time periods. There was no evidence of functional redundancy or compensation by other taxa after the loss of amphibians, even after 8 years.

1 aRantala, H.M.1 aNelson, A.M.1 aFulgoni, J.N.1 aWhiles, M.R.1 aHall, R.O.1 aDodds, W., K.1 aVerburg, P.1 aHuryn, A.1 aPringle, C..1 aKilham, S.S.1 aLips, K.R.1 aColon-Gaud, C.1 aRugenski, A.T.1 aPeterson, S.D.1 aFritz, K.1 aMcLeran, K.E.1 aConnelly, S. uhttps://onlinelibrary.wiley.com/doi/abs/10.1111/fwb.12505