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In tropical regions the extent of agricultural land is increasing rapidly at the expense of natural forest, with associated losses of biodiversity and ecosystem services. Agroforestry has long been proposed as a more sustainable agricultural system, conserving biodiversity while providing significant local livelihoods. In this context, camera traps were deployed to compare communities of large mammals between natural forest (22,272 hours across 24 deployments) and extensively managed coffee forest (19,059 hours, 23 deployments) for the first time in the south-west Ethiopian highlands. Mammal communities in the two forest types were similar in species richness and Shannon diversity but differed in community composition. Significant indicator species of coffee forest were the crested porcupine Hystrix cristata and the Ethiopian hare Lepus fagani, whereas leopards Panthera pardus and civets Civettictis civetta had a preference for natural forest. The number of detections of mammals was higher in coffee forest, where activity patterns were predominantly crepuscular and nocturnal, which may be a direct adaptation to frequent human disturbance. In natural forest, mammal activity peaked during daytime. Despite the high mammal diversity in extensively managed coffee forest, it cannot fully replace natural forest as a habitat for large mammals. We suggest that a balanced landscape mosaic of coffee and natural forest may be a valuable combination for both conservation and coffee cultivation. [ABSTRACT FROM AUTHOR]

Despite the importance of water purification to society, it is one of the more difficult wetland ecosystem services to quantify. It remains an issue in ecosystem service assessments where rapid estimates are needed, and poor-quality indicators are overused. We attempted to quantify the water purification service of South African palmiet wetlands (valley-bottom peatlands highly threatened by agriculture). First, we used an instantaneous catchment-scale mass balance sampling approach, which compared the fate of various water quality parameters over degraded and pristine sections of palmiet wetlands. We found that pristine palmiet wetlands acted as a sink for water, major cations, anions, dissolved silicon and nutrients, though there was relatively high variation in these trends. There are important limitations to this catchment-scale approach, including the fact that at this large scale there are multiple mechanisms (internal wetland processes as well as external inputs) at work that are impossible to untangle with limited data. Therefore, secondly, we performed a small field-scale field survey of a wetland fragment to corroborate the catchment-scale results. There was a reasonable level of agreement between the results of the two techniques. We conclude that it appears possible to estimate the water purification function of these valley-bottom wetlands using this catchment-scale approach. [ABSTRACT FROM AUTHOR]

Many endangered plant species remain absent in rewetted, previously drained fens. We performed a 3-year introduction experiment with endangered fen species (9 Carex - and 6 bryophyte species) in 4 hydrologically restored fens to investigate which factors hamper establishment and survival. Carex species were introduced as adults and seedlings, mosses as gametophytes. Introductions were done on (initially) bare soil, which allowed us to exclude excessive competition for light during the first year. First year survival of the transplants was high in all fens (mean survival = 96%), indicating that there were no direct abiotic constraints on establishment. However, survival analysis revealed that a decrease in relative light intensity (RLI) at the soil surface during consecutive years (indicating an increase in biotic competition for light) drove high mortality rates in most species. As a result, overall final survival was lowest in the two most productive (low light) fens (mean survival = 38%), while most transplants persisted in the two less productive (high light) fens (mean survival = 79%). Taller and faster-growing Carex species were able to outgrow light limitation near the soil surface, and thus had a higher overall survivability than smaller and slower-growing species. Light limitation also drove the loss of 5 out of 6 bryophyte species. We conclude that both dispersal limitation and asymmetric competition for light may explain the lack and loss of small and endangered plant species in rewetted fens. A minimum empirical threshold of c. 30% relative light intensity near the soil surface is required for successful introduction. [ABSTRACT FROM AUTHOR]

Anthropogenic eutrophication of wetlands may have a significant impact on the global biogeochemical silicon (Si) cycle, as Si filtering by wetland vegetation codetermines fluxes of Si towards the oceans. We experimentally investigated how macronutrient (NPK) enrichment alters total Si storage and Si stoichiometry in litter from six wetland species of Carex, which we related to other parameters of litter quality and litter decomposition rates. Nutrient enrichment stimulated primary biomass production, which resulted in an increased total Si storage in plants. However, this eutrophication-induced stimulatory effect on Si fixation in plant biomass was counterbalanced by consistently lower (up to 50 % reduction) litter Si concentrations in all species, suggesting a plant-physiological response following the relief of nutrient stress. Moreover, competitive species (typical for eutrophic conditions) tended to accumulate less Si (per g DM) than slow-growing species (typical for nutrient-poor conditions). Finally, a negative correlation between litter Si concentrations and litter decomposition rates in nutrient-poor environments suggested an inhibiting effect of Si on decomposition. However, negative correlations between litter Si concentrations and litter macronutrient concentrations as well as positive correlations between litter Si concentrations and C:N and lignin:N ratios indicated a strong interdependence of Si with other litter quality parameters that determine decomposition. We conclude that stimulatory effects of eutrophication on total Si storage in wetland vegetation (following an increase in biomass production) need to be balanced with the plant-physiological response of lower tissue Si concentrations. We argue that rates of Si cycling are likely to be altered through shifts in litter quality and decomposition rates. [ABSTRACT FROM AUTHOR]

Rewetted, previously drained fens often remain sources rather than sinks for carbon and nutrients. To date, it is poorly understood which soil characteristics stimulate carbon and nutrient mobilization upon rewetting. Here, we assess the hypothesis that a large pool of iron in the soil negatively affects fen restoration success, as flooding-induced iron reduction (Fe3+ to Fe2+) causes a disproportionate breakdown of organic matter that is coupled with a release of inorganic compounds. We collected intact soil cores in two iron-poor and two iron-rich drained fens, half of which were subjected to a rewetting treatment while the other half was kept drained. Prolonged drainage led to the mobilization of nitrate (NO3-, > 1 mmol L-1) in all cores, regardless of soil iron content. In the rewetted iron-rich cores, a sharp increase in pore water iron (Fe) concentrations correlated with concentrations of inorganic carbon (TIC, > 13 mmol L-1) and dissolved organic carbon (DOC, > 16 mmol L-1). Additionally, ammonium (NH4+) accumulated up to phytotoxic concentrations of 1 mmol L-1 in the pore water of the rewetted iron-rich cores. Disproportionate mobilization of Fe, TIC, DOC and NH4+ was absent in the rewetted iron-poor cores, indicating a strong interaction between waterlogging and iron-mediated breakdown of organic matter. Concentrations of dissolved phosphorus (P) rose slightly in all cores upon rewetting, but remained low throughout the experiment. Our results suggest that large pools of iron in the top soil of drained fens can hamper the restoration of the fen’s sink-service for ammonium and carbon upon rewetting. We argue that negative effects of iron should be most apparent in fens with fluctuating water levels, as temporary oxygenation allows frequent regeneration of Fe3+. We conclude that rewetting of iron-poor fens may be more feasible for restoration. [ABSTRACT FROM AUTHOR]

Global land-use intensification and drainage has altered the biogeochemical properties of many peatlands, and concomitant eutrophication has led to a loss of low-competitive fen species. We investigated the hypothesis that removal of a degraded and eutrophied top peat layer, thereby exposing an underlying peat layer, can improve conditions for rich fen restoration. We studied the long-term (3–18 years) effects of past topsoil removal in six rich fens in Western Europe by comparing topsoil removal plots with (untouched) control plots. Overall, topsoil removal plots were characterized by lower bulk densities and soil nutrient pools of P and KCl-extractable NH 4 + , while organic matter contents and soil C:N ratios were higher. Pore water concentrations of NO 3 − and NH 4 + also decreased in the topsoil removal plots, while concentrations of base cations (Ca 2+ , Mg 2+ , Na + , K + ) and HCO 3 − increased. Furthermore, lower nutrient levels appeared to restrict herb biomass production in the topsoil removal plots, so that optimized light conditions led to the establishment of light-demanding target species and a significant increase in bryophyte cover. Multivariate analysis revealed that most variation in vegetation assembly was due to higher groundwater levels in the topsoil removal plots, closely followed by a higher relative light intensity (RLI) at surface level, lower pore water nutrient (NH 4 + ) concentrations, and higher concentrations of base cations. We conclude that topsoil removal can be an effective mechanism to “reset” a degraded peatland to its initial state of nutrient limitation, base saturation and high availability of light, thereby improving the conservation prospects of endangered rich fen communities. [ABSTRACT FROM AUTHOR]

Foraging activity in animals reflects a compromise between acquiring food and avoiding predation. The risk allocation hypothesis predicts that prey animals optimize this balance by concentrating their foraging activity at times of relatively low predation risk, as much as their energy status permits, but empirical evidence is scarce. We used a unique combination of automated telemetry, manual radiotelemetry and camera trapping to test whether activity at high risk times declined with food availability as predicted in a Neotropical forest rodent, the Central American agouti, Dasyprocta punctata. We found that the relative risk of predation by the main predator, the ocelot, Leopardus pardalis, estimated as the ratio of ocelot to agouti activity on camera trap photographs, was up to four orders of magnitude higher between sunset and sunrise than during the rest of the day. Kills of radiotracked agoutis by ocelots during this high-risk period far exceeded expectations given agouti activity. Both telemetric monitoring of radiotagged agoutis and camera monitoring of burrow entrances indicated that agoutis exited their burrows later at dawn, entered their burrows earlier at dusk and had lower overall activity levels when they lived in areas with higher food abundance. Thus, agoutis avoided activity during the high-risk period more strongly when access to food was higher. Our study provides quantitative empirical evidence of prey animals concentrating their activity at times of relatively low predation risk. [ABSTRACT FROM AUTHOR]

Soil inoculation from plant species-rich into species-poor grasslands may enable the establishment of self-facilitating networks between microbes and vegetation, thereby steering ecosystem development. We conducted a three-year experiment that covered a wide range of post-agricultural grasslands to determine how succession is affected by the interactive effects of edaphic properties, grass layer removal and hay or soil fragment transfer from a late-successional donor grassland. Soil inoculation generally impacted community assembly of vegetation and fungi, but not of prokaryotes. Effects were strongest when preceded by removal of the grass layer, indicating the importance of priority effects and dispersal limitation. Inoculation enabled the establishment of putative rhizosphere-associated fungal taxa, particularly from the families Helotiaceae, Glomeraceae and Archaeorhizomycetaceae. Nonetheless, effect sizes were mostly small, as was overall resemblance of the receptor grasslands to the donor. Fungal communities were primarily shaped by environmental filters and only reached a high resemblance to the donor in nutrient-poor sites. Shifts in the vegetation were strongest in those grasslands where the mycobiome more closely resembled that of the donor. Soil inoculation generally facilitates colonization by target plant and fungal communities, where establishment success of the former can be predicted by the latter, but the final outcome of succession is environmentally determined. • Soil inoculation impacts community assembly of vegetation and fungi in grasslands. • Inoculation enables the establishment of putative rhizosphere-associated fungal taxa. • Local environmental filters determine the final outcome of succession. [ABSTRACT FROM AUTHOR]

Many peatlands have been affected by water table drawdown and carbon loss. Rewetting may push a drained peatland back towards its pre-degradation state and may result in renewed carbon accumulation, but there is little consensus on its effectiveness. Moreover, rewetting typically leads to a spike in methane emissions. Whether rewetting suffices to restore drained peatlands hinges to a large extent on whether microbial communities, and the functions they perform, are able to recover. We studied prokaryote communities in fens across temperate Europe using high-throughput amplicon sequencing of 16S rRNA, within the framework of RePeat (REstoration and prognosis of PEAT formation in fens - linking diversity in plant functional traits to soil biological and biogeochemical processes 2016-2019; BiodiVErSA). We included undrained, drained and rewetted fens to evaluate the effects of fen rewetting on microbial recovery. Prokaryote communities were highly stratified with depth, and there was a clear division between communities of drained and undrained fens. Prokaryote communities in rewetted fens were largely similar to those of undrained fens, but only where soil organic matter contents and bulk densities were respectively still high and low. Our results suggest that altered physio-chemical peat properties following drainage may hamper complete prokaryote recovery after rewetting, at least in the short term. [ABSTRACT FROM AUTHOR]

The Neotropics have many plant species that seem to be adapted for seed dispersal by megafauna that went extinct in the late Pleistocene. Given the crucial importance of seed dispersal for plant persistence, it remains a mystery how these plants have survived more than 10,000 y without their mutualist dispersers. Here we present support for the hypothesis that secondary seed dispersal by scatterhoarding rodents has facilitated the persistence of these largeseeded species. We used miniature radio transmitters to track the dispersal of reputedly megafaunal seeds by Central American agoutis, which scatter-hoard seeds in shallow caches in the soil throughout the forest. We found that seeds were initially cached at mostly short distances and then quickly dug up again. However, rather than eating the recovered seeds, agoutis continued to move and recache the seeds, up to 36 times. Agoutis dispersed an estimated 35% of seeds for >100 m. An estimated 14% of the cached seeds survived to the next year, when a new fruit crop became available to the rodents. Serial video-monitoring of cached seeds revealed that the stepwise dispersal was caused by agoutis repeatedly stealing and recaching each other's buried seeds. Although previous studies suggest that rodents are poor dispersers, we demonstrate that communities of rodents can in fact provide highly effective long-distance seed dispersal. Our findings suggest that thieving scatter-hoarding rodents could substitute for extinct megafaunal seed dispersers of tropical large-seeded trees. [ABSTRACT FROM AUTHOR]

• Biophysicochemical factors explained most variability in C and N stocks. • Succession age and plant litter production of minor importance. • MAOM exclusively associated with abiotic factors... • ...while POM and aggregate fractions were related to both biotic and abiotic factors. • Crucial to know the form in which C and N exist in soil to inform proper management. A better understanding of factors controlling the distribution of soil organic matter (SOM) in differently stabilized pools in soils during ecosystem development is essential to more efficiently manage soil as a C sink and aid global warming mitigation. We, thus, investigated C and N stocks in bulk soil and differently stabilized soil fractions (free particulate organic matter (fPOM), micro- and macroaggregates, and mineral-associated organic matter (MAOM)), in seven chronosequences comprising primary and secondary successions at various locations in Europe and tested the influence of multiple environmental parameters on these C and N stocks. Best-subset multiple regression indicated that plant litter production and succession age were of minor importance. Above a certain threshold of organic matter inputs to the soil, changes in the quantity of such inputs may have little direct effect on the partitioning of organic matter to various soil fractions. Instead, biophysicochemical soil properties (such as pH and PLFA and clay contents) were the best predictors for both C and N stocks. We also found a shift in the relevance of biotic and abiotic factors from fPOM and the various aggregate fractions to MAOM, the latter being exclusively associated with pH and the clay content. This indicates that sites dominated by MAOM likely more slowly react to management interventions, such as increasing or diversifying organic matter inputs, than sites dominated by fractions more responsive to biotic factors, such as fPOM. Finally, as compared to primary successions, secondary successions were associated with higher C and N stocks in aggregate fractions, pointing towards better conditions for soil structure formation in the latter. Our results highlight the need to elucidate the form in which C and N exist in the soil for selection of proper management strategies and that soil biophysicochemical parameters may have a disparately larger impact on the partitioning of C and N to variously stabilized soil fractions than the rate of organic matter inputs. [ABSTRACT FROM AUTHOR]

The formation of soil aggregates is related to the stability of soil organic carbon, which distinguishes the living conditions of microbial communities in different micro-niches. Here, we investigated fungal and bacterial community structure, networks, biomass and respiration in individual micro-niches between and within soil aggregates using seven different chronosequences (both primary and secondary successions from pioneer stages to well-developed ecosystems) on a European-scale gradient from a maritime climate in Belgium to a more continental climate in Hungary. We showed that geographical location was the most important factor (74% for bacterial community, 53% for fungal community) affecting microbial community composition, while soil aggregates (5% for bacterial community and 12% for fungal community) were the second most important factor followed by age of succession and vegetation. Moreover, aggregates (52%) were the most important factor influencing the biomass of major microbial groups, followed by location (37%) and age of succession (6%). Interestingly, macro-aggregates had less interconnected microbial networks and low microbial respiration rates compared to other aggregate sizes. We therefore hypothesize that the embedding of organic particles in the mineral matrix of macro-aggregates is a crucial point in microbial community organization, as evidenced by microbial community connectivity and microbial respiration. Our results demonstrate the importance of soil aggregates for microbial community organization and soil carbon stabilization. • Soil aggregates were an important determinant of microbial community structure and biomass. • Microbial community networks were less interconnected in macro-aggregates over wide areas. • Macro-aggregates had lower microbial respiration rates compared to the other aggregates. • Microbial community network degrees were correlated with microbial respiration. [ABSTRACT FROM AUTHOR]