DOI: 10.5061/dryad.g886d9v
title: Data from: Organic matter and nutrient inputs from large wildlife influence ecosystem function in the Mara River, Africa

description: Animals can be important vectors for the movement of resources across
 ecosystem boundaries. Animals add resources to ecosystems primarily
 through egestion, excretion and carcasses, and the stoichiometry and
 bioavailability of these inputs likely interacts with characteristics of
 the recipient ecosystem to determine their effects on ecosystem function.
 We studied the influence of hippopotamus excretion/egestion and wildebeest
 carcasses, and their interactions with discharge, in the Mara River,
 Kenya. We measured nutrient dissolution and decomposition rates of
 wildlife inputs, the influence of inputs on nutrient concentrations and
 nutrient limitation in the river and the influence of inputs on biofilm
 growth and function in both experimental streams and along a gradient of
 inputs in the river. We found that hippopotamus excretion/egestion
 increase ammonium and coarse particulate organic matter in the river, and
 wildebeest carcasses increase ammonium, soluble reactive phosphorus, and
 total phosphorus. Concentrations of dissolved carbon and nutrients in the
 water column increased along a gradient of wildlife inputs and during low
 discharge, although concentrations of particulate carbon decreased during
 low discharge due to deposition on the river bottom. Autotrophs were
 nitrogen-limited, and heterotrophs were carbon-limited and nitrogen- and
 phosphorus- co-limited, upstream of animal inputs, but there was no
 nutrient limitation downstream of inputs. In experimental streams, hippo
 and wildebeest inputs together increased biofilm GPP and R. These results
 differed in the river, where low concentrations of hippo inputs increased
 gross primary production (GPP) and respiration (R) of biofilms, but high
 concentrations of hippo inputs in conjunction with wildebeest inputs
 decreased GPP. Our research shows that inputs from large wildlife
 alleviate nutrient limitation and stimulate ecosystem metabolism in the
 Mara River, and that the extent to which these inputs subsidize the
 ecosystem is mediated by the quantity and quality of inputs and discharge
 of the river ecosystem. Thus, animal inputs provide an important
 ecological subsidy to this river, and animal inputs were likely important
 in many other rivers prior to the widespread extirpation of large
 wildlife.
description: Subalusky_2018_mara_biochemical_oxygen_demandThis file contains data on biochemical oxygen demand measured over 5 days in 310 ml bottles in water samples collected from the water column at our three primary study sites.Subalusky_2018_mara_experimental_stream_tilesThis file contains data on the biofilm growth and production of indvidual ceramic tiles placed in experimental streams and destructively sampled weekly to measure biofilm growth over time.Subalusky_2018_mara_hippo_feces_decomp_litterbagsThis file contains data on decomposition rates of hippo feces in litterbags in the Mara River.Subalusky_2018_mara_nutrient_dissolution_chambersThis file contains data on nutrient dissolution of hippo feces and wildebeest tissue measured using 5L chamber experiments filled with river water.Subalusky_2018_mara_nutrient_limitation_assaysThis file contains data on biofilm growth on nutrient-diffusing substrates, comprised of glass discs (for measurements of cholorophyll a) and cellulose sponges (for measurements of respiration) on cups of agar amended with different nutrients.Subalusky_2018_mara_river_biofilm_alldataThis file contains data on the biofilm growth and production on individual ceramic tiles placed in the Mara River at our three primary study sites for 3-4 weeks at a time; these are the individual values for 4-5 tiles at each site at each sampling period. The mean values for each site and visit were used for analysis.Subalusky_2018_mara_river_biofilm_summary_dataThis file contains data on the mean biofilm growth and production on ceramic tiles placed in the Mara River at our three primary study sites for 3-4 weeks at a time; these are the mean values averaged for 4-5 tiles at each site at each sampling period. These are the data that were used for analysis in the paper.Subalusky_2018_mara_river_nutrients_tenpttransectThis file contains data on carbon and nutrient concentrations measured along a 10 point sampling transect down the Mara River, and the mean and standard error of all C and nutrient measurements over the period of study at our three primary study sites.Subalusky_2018_mara_river_physicochem_nutrient_dataThis file contains data on discharge and water column parameters measured monthly at our three primary study sites in the Mara River from Jun-Aug 2011, Jul-Dec 2012, and Aug 2013-Mar 2014.READMEA text file describing each data file the data package.