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Ecosystems
Journal Prestige (SJR): 2.081  Citation Impact (citeScore): 4 Number of Followers: 33  Hybrid journal (It can contain Open Access articles)ISSN (Print) 1435-0629 - ISSN (Online) 1432-9840 Published by Springer-Verlag  [2468 journals]
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- Nitrogen and Phosphorus Addition Affect Soil Respiration in Northern
Hardwood Forests-
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Abstract: Abstract Soil respiration is the largest single efflux in the global carbon cycle and varies in complex ways with climate, vegetation, and soils. The suppressive effect of nitrogen (N) addition on soil respiration is well documented, but the extent to which it may be moderated by stand age or the availability of soil phosphorus (P) is not well understood. We quantified the response of soil respiration to manipulation of soil N and P availability in a full-factorial N x P fertilization experiment spanning 10 years in 13 northern hardwood forests in the White Mountains of New Hampshire, USA. We analyzed data for 2011 alone, to account for potential treatment effects unique to the first year of fertilization, and for three 3-year periods; data from each 3-year period was divided into spring, summer, and fall. Nitrogen addition consistently suppressed soil respiration by up to 14% relative to controls (p ≤ 0.01 for the main effect of N in 5 of 10 analysis periods). This response was tempered when P was also added, reducing the suppressive effect of N addition from 24 to 1% in one of the ten analysis periods (summer 2012–2014, p = 0.01 for the interaction of N and P). This interaction effect is consistent with observations of reduced foliar N and available soil N following P addition. Mid-successional stands (26–41 years old at the time of the first nutrient addition) consistently had the lowest rates of soil respiration across stand age classes (1.4–6.6 µmol CO2 m−2 s−1), and young stands had the highest (2.5–8.5 µmol CO2 m−2 s−1). In addition to these important effects of treatment and stand age, we observed an unexpected increase in soil respiration, which doubled in 10 years and was not explained by soil temperature patterns, nutrient additions, or increased in fine-root biomass.
PubDate: 2024-08-14
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- Reviewer Acknowledgement 2023
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PubDate: 2024-08-07
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- Impacts of Compost Amendment Type and Application Frequency on a
Fire-Impacted Grassland Ecosystem-
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Abstract: Abstract Composting organic matter can lower the global warming potential of food and agricultural waste and provide a nutrient-rich soil amendment. Compost applications generally increase net primary production (NPP) and soil water-holding capacity and may stimulate soil carbon (C) sequestration. Questions remain regarding the effects of compost nitrogen (N) concentrations and application rates on soil C and greenhouse gas dynamics. In this study, we explored the effects of compost with different initial N quality (food waste versus green waste compost) on soil greenhouse gas fluxes, aboveground biomass, and soil C and N pools in a fire-impacted annual grassland ecosystem. Composts were applied annually once, twice, or three times prior to the onset of the winter rainy season. A low-intensity fire event after the first growing season also allowed us to explore how compost-amended grasslands respond to burning events, which are expected to increase with climate change. After four growing seasons, all compost treatments significantly increased soil C pools from 9.5 ± 0.9 to 30.2 ± 0.7 Mg C ha−1 (0–40 cm) and 19.5 ± 0.9 to 40.1 ± 0.7 Mg C ha−1 (0–40 cm) relative to burned and unburned controls, respectively. Gains exceeded the compost-C applied, representing newly fixed C. The higher N food waste compost treatments yielded more cumulative soil C (5.2–10.9 Mg C ha−1) and aboveground biomass (0.19–0.66 Mg C ha−1) than the lower N green waste compost treatments, suggesting greater N inputs further increased soil stocks. The three-time green waste application increased soil C and N stocks relative to a single application of either compost. There was minimal impact on net ecosystem greenhouse gas emissions. Aboveground biomass accumulation was higher in all compost treatments relative to controls, likely due to increased water-holding capacity and N availability. Results show that higher N compost resulted in larger C gains with little offset from greenhouse gas emissions and that compost amendments may help mediate effects of low-intensity fire by increasing fertility and water-holding capacity.
PubDate: 2024-08-05
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- Soil Legacies of Tree Species Composition in Mature Forest Affect Tree
Seedlings’ Performance-
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Abstract: Abstract Trees affect the biotic and abiotic properties of the soil in which they grow. Tree species-specific effects can persist for a long time, even after the trees have been removed. We investigated to what extent such soil legacies of different tree species may impact tree seedlings in their emergence and growth. We performed a plant–soil feedback experiment, using soil that was conditioned in plots that vary in tree species composition in Białowieża Forest, Poland. Soil was taken from plots varying in proportion of birch, hornbeam, pine, and oak. In each soil, seeds of the same four target species were sown in pots. Seedling emergence and growth were monitored for one growing season. To further explore biotic implications of soil legacies, ectomycorrhizal root tip colonization of oak, a keystone forest species, was determined. We found no effect of soil legacies of tree species on the emergence measures. We, however, found a clear negative effect of pine legacies on the total biomass of all four seedling species. In addition, we found relationships between the presence of pine and soil fertility and between soil fertility and root tip colonization. Root tip colonization was positively correlated with the biomass of oak seedlings. We conclude that tree species can leave legacies that persist after that species has been removed. These legacies influence the growth of the next generation of trees likely via abiotic and biotic pathways. Thus, the choice of species in today’s forest may also matter for the structure and composition of future forests.
PubDate: 2024-08-05
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- Influence of Native Woody Understory on Invasive Grasses and Soil Nitrogen
Dynamics Under Plantation and Remnant Montane Tropical Trees-
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Abstract: Abstract While the influence of canopy trees on soils in natural and restored forest environments is well studied, the influence of understory species is not. Here, we evaluate the effects of outplanted native woody understory on invasive grass biomass and soil nutrient properties in heavily grass-invaded 30 + year-old plantations of a native N-fixing tree Acacia koa in Hawai‘i. We analyze soils from under A. koa trees with versus without planted woody understory and compare these to soils from under remnant pasture trees of the pre-deforestation dominant, Metrosideros polymorpha where passive recruitment of native woody understory has occurred since the cessation of grazing. Simultaneously, we experimentally planted understory species at three times the density used by managers to see if this could quickly decrease grass biomass and change soil nutrient dynamics. We found that invasive grass biomass declined with understory planting in surveyed and experimental sites. Yet, woody understory abundance had no effect on N cycling. Short-term N availability and nitrification potential were higher under A. koa than M. polymorpha trees regardless of understory. Net N mineralization either did not differ (~ 1 mo) between canopy species or was higher (171 day incubations) under remnant M. polymorpha where organic matter was also higher. The only influence of understory on soil was a positive correlation with loss-on-ignition (organic matter) under M. polymorpha. We also demonstrate differential controls over N cycling under the two canopy tree species. Overall, understory restoration has not changed soil characteristics even as invasive grass biomass declines.
PubDate: 2024-07-29
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- Dynamics of Organic Matter Transport, Storage, and Processing in a
Non-perennial Mediterranean River Network-
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Abstract: Abstract Freshwater ecosystems play a key role in the global carbon cycle by collecting, transporting, and processing a significant portion of global organic carbon. These processes can be disrupted in non-perennial rivers due to their changing hydrological patterns. We investigated how environmental factors influence organic matter dynamics in the Algars, a Mediterranean non-perennial river basin in the North-East Iberian Peninsula. We conducted seasonal sampling in 16 sites across the river network, collecting samples for (i) storage of benthic organic matter, (ii) transport of dissolved organic carbon and particulate organic matter, and (iii) organic matter processing via aerobic respiration in sediments (Raz–Rru method). We observed pronounced spatial and temporal fluctuations in organic matter processes, especially during distinct periods like summer and autumn. Consistent seasonal patterns of organic matter transport showed a remarkable longitudinal increase downstream, similar to observed aerobic respiration in sediments. Notably, high-flow events doubled observed seasonal transport (mean DOC load: 2344 ± 735 kg/day). Irregular spatial storage patterns between dry and wet channel sections were related to land use and flow intermittency. Notably, storage in dry channel sections was generally ten times higher than wet sections. Our study emphasizes the intricate influence of specific environmental variables on organic matter processes, within different organic matter fractions (for example, coarse and dissolved organic matter). Frequency of non-flow events, seasonal hydrological changes, and land use predominantly govern organic matter dynamics in the Algars basin. Understanding organic carbon dynamics in non-perennial systems will help estimate the impact of hydrological alterations associated with global change on river systems.
PubDate: 2024-07-19
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- Correction: Carbon Stocks and Transfers in Coniferous Boreal Forests Along
a Latitudinal Gradient-
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PubDate: 2024-06-28
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- Calculating Nitrogen Uptake Rates in Forests: Which Components Can Be
Omitted, Simplified, or Taken from Trait Databases and Which Must Be
Measured In Situ'-
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Abstract: Abstract Quantifying nitrogen uptake rates across different forest types is critical for a range of ecological questions, including the parameterization of global climate change models. However, few measurements of forest nitrogen uptake rates are available due to the intensive labor required to collect in situ data. Here, we seek to optimize data collection efforts by identifying measurements that must be made in situ and those that can be omitted or approximated from databases. We estimated nitrogen uptake rates in 18 mature monodominant forest stands comprising 13 species of diverse taxonomy at the Morton Arboretum in Lisle, IL, USA. We measured all nitrogen concentrations, foliage allocation, and fine root biomass in situ. We estimated wood biomass increments by in situ stem diameter and stem core measurements combined with allometric equations. We estimated fine root turnover rates from database values. We analyzed similar published data from monodominant forest FACE sites. At least in monodominant forests, accurate estimates of forest nitrogen uptake rates appear to require in situ measurements of fine root productivity and are appreciably better paired with in situ measurements of foliage productivity. Generally, wood productivity and tissue nitrogen concentrations may be taken from trait databases at higher taxonomic levels. Careful sorting of foliage or fine roots to species is time consuming but has little effect on estimates of nitrogen uptake rate. By directing research efforts to critical in situ measurements only, future studies can maximize research effort to identify the drivers of varied nitrogen uptake patterns across gradients.
PubDate: 2024-06-27
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- Glacial Meltwater Increases the Dependence on Marine Subsidies of Fish in
Freshwater Ecosystems-
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Abstract: Abstract In a warming world, the input of glacier meltwater to inland water ecosystems is predicted to change, potentially affecting their productivity. Meta-ecosystem theory, which posits that the nutrient availability in the recipient ecosystem can determine the extent of cross-ecosystem boundary utilization, can be useful for studying landscape-scale influences of glacier meltwater on inland waters. Here, we investigate how the input of glacier meltwater in a river system in Southern Greenland influences the utilization of marine subsidies in freshwater fish. Our study system comprised four sites, with controls for glacial meltwater and marine subsidies, harboring a partially migrating population of arctic char, meaning that some individuals migrate to the ocean and others remain in freshwaters, and two fully resident populations as a freshwater reference. We assessed the incorporation of marine carbon in freshwater resident char using both bulk and amino acid stable isotope analysis of muscle tissue. In the population with partial migration, marine subsidies were a significant resource for resident char individuals, and estimates of trophic position suggest that egg cannibalism is an important mechanism underlying the assimilation of these marine subsidies. In proglacial streams, namely those with high glacial meltwater, the total dependence on marine subsidies increased and reached 83% because char become cannibals at smaller sizes. In the configuration of our focal meta-ecosystem, our results suggest that the importance of marine subsidies to freshwater fish strengthens within increasing meltwater flux from upstream glaciers.
PubDate: 2024-06-26
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- Invertebrate-Mediated Ecosystem Processes are Resilient to Disturbance
Across a Land-Use Gradient in Borneo-
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Abstract: A fundamental challenge for ecologists is to evaluate the effects of anthropogenic disturbance on ecosystem processes and functions. Tropical rainforests in Borneo are biologically diverse and provide an array of ecosystem functions and services. However, these forests are being logged and converted to agricultural plantations at a rapid pace. While there are numerous studies on the impacts of these land-use changes on biodiversity, there are far fewer that investigate the consequences of forest disturbance for ecosystem functioning. We investigated the impacts of land-use change in Bornean tropical rainforests on invertebrate-mediated functions using a suite of six easily measurable processes that are linked to nutrient cycling and plant regeneration, and which can be used as indicators of the degree of disturbance and the health of the forest. We explored whether the conversion of primary forest to logged, fragmented forest or agricultural plantations altered the ecosystem processes of dung removal, predation of insect herbivores, functional activity of soil invertebrates, bioturbation, seed removal, and decomposition. Overall, ecosystem processes remained resistant to habitat change except for seed removal, which was lower in heavily logged forests and plantations than in primary forests. This suggests that, despite the loss of many species when forests are logged and converted to agriculture, ecosystem processes provided by invertebrates can remain robust across land-use gradients. Graphical
PubDate: 2024-06-13
DOI: 10.1007/s10021-024-00917-w
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- Plant Multi-element Coupling as an Indicator of Nutritional Mismatches
Under Global Change-
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Abstract: Abstract Global biogeochemical cycles have been widely altered due to human activities, potentially compromising the ability of plants to regulate their metabolism. We grew experimental herbaceous communities simulating the understory of eucalypt forests from southeastern Australia to evaluate the effects of elevated CO2 (400 vs. 650 ppm) and changes in soil resource availability (high-low water and high-low P) on the concentration of fourteen essential plant macro- and micronutrients, and their degree of coupling. Coupling was based on correlations among all elements in absolute value and a null modeling approach. According to the ancient nature of Australian soils, P addition was the main driver of changes in plant tissue chemistry, increasing the concentrations of P, Mg, Ca, and Mn and reducing the concentrations of C, N, S, Na, and Cu. Most treatment combinations showed coupled patterns of plant elements, particularly under ambient CO2. However, under elevated CO2, elements in plant tissues became more decoupled, which was interpreted as the result of a lack of enough supply of a range of elements to satisfy greater demands. Across treatments, P, Mn, and N were the least coupled elements, while K, Ca, and Fe were the most coupled ones. We provide evidence that plant element coupling was positively related to the concentration and coupling of elements measured in soils worldwide, suggesting that plant element coupling is conserved. Our results provide compelling evidence that evaluating the coupling of a representative range of chemical elements in plant tissues may represent a highly novel and powerful indicator of nutritional mismatches between demand and supply under specific environmental circumstances, including in a resource-altered global change context.
PubDate: 2024-06-12
DOI: 10.1007/s10021-024-00914-z
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- Temporal Development of Microhabitats on Living Habitat Trees in Temperate
European Forests-
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Abstract: Tree-related microhabitats (TreMs) have been promoted as indicators of forest biodiversity and to guide conservation practices. Ensuring the provision of diverse TreMs in the long term is crucial for the survival of many forest-dwelling species. Yet, this task is challenging in the absence of information regarding TreM dynamics. We analysed the temporal development of TreMs on 11,569 living trees in temperate European forests. To identify drivers of change in TreM abundance and richness over a period of 3–12 years, we estimated the rates of TreM persistence and loss events at the tree-level using survival analysis methods: persistence was characterised by consistency and increment events (when TreM numbers were maintained or increased) and loss was defined as a reduction in TreM numbers or their disappearance. Stratified Cox proportional hazards models were fitted for different TreM groups. Our study revealed a highly dynamic TreM development on living habitat trees, particularly on large trees. While specific TreMs are prone to disappearing, irrespective of tree species or TreM groups, total TreM richness persists over a 12-year period. TreMs such as crown deadwood, epiphytes or woodpecker cavities are prone to decrease in the long term. However, large trees were more likely to maintain a certain degree of TreM richness. Increasing diameters resulted in high persistence rates in seven TreM groups and concomitantly low loss rates in four of them (exposed sap- and heartwood, concavities). Selecting habitat trees based on TreMs should consider the likelihood of TreMs being lost over time, to ensure the long-term provision of microhabitats for associated species. Graphical
PubDate: 2024-06-12
DOI: 10.1007/s10021-024-00915-y
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- Spatial Distribution of Carbon Stocks Along Protected and Non-protected
Coastal Wetland Ecosystems in the Gulf of Mexico-
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Abstract: Abstract Coastal wetland ecosystems in the Gulf of Mexico provide a variety of services including high rates of carbon sequestration and storage, making their assessment and conservation essential. This study aimed to determine the spatial distribution of carbon stocks in protected and non-protected coastal wetland ecosystems along the Gulf of Mexico in Mexico. Aboveground carbon (AGC) and belowground carbon (BGC) stocks were quantified using predictive random forest models. The study analyzed carbon estimates in AGC and BGC across different coastal wetland ecosystems and assessed the carbon storage of protected areas (PAs) and non-protected areas (non-PAs) for carbon conservation. Field surveys provided biomass and soil carbon data for modeling training, incorporating environmental features such as canopy height, vegetation indices, and soil characteristics. The results reveal differences in carbon stocks quantities among various vegetation types, with mixed mangroves exhibiting the highest AGC stock (93.7 ± 8.4 Mg C ha−1) and herbaceous wetlands displaying the smallest range (3.9 ± 1.3 Mg C ha−1) across sites. Notably, cattail marshes showed the highest average BGC stocks (505.6 ± 86.8 Mg C ha−1), influenced by factors such as soil characteristics and land cover. Spatial distribution maps of AGC and BGC provided insights into areas of high and low carbon storage. Interestingly, non-PAs showed higher carbon stocks than certain PAs, emphasizing the importance of including both protected and non-protected areas in conservation efforts. These findings highlight the significance of carbon storage across coastal wetland ecosystems, and the need for comprehensive conservation strategies to preserve their valuable ecosystem services.
PubDate: 2024-06-05
DOI: 10.1007/s10021-024-00918-9
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- Tree Species Diversity Affects Litter Decomposition via Modification of
the Microenvironment-
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Abstract: Abstract Decomposition is a key determinant of forest functioning, controlling nutrient and carbon cycling. Although litter-mixing effects on decomposition (that is, using mixtures of litter of different species) have been studied extensively, less is known about the indirect effects of modified microenvironments via overstory tree species mixing. To investigate the effects of tree species diversity on decomposition, we installed 384 standardized litterbags, filled with leaf litter of four broadleaved tree species with contrasting litter quality, in a large, 10-year-old tree diversity experiment. To quantify microenvironments, we used microclimate sensors, below-canopy rain gauges and measured soil characteristics. We then analysed indirect tree species diversity effects, that is, tree species richness effects on mass loss rates via tree species-induced alterations in the microclimate, throughfall and soil characteristics. We found that understory microenvironmental conditions indeed affect mass loss rates, with the main drivers differing among incubation stages. Predominantly soil phosphorus, but also vapour pressure deficit and throughfall amounts, was negatively associated with mass loss rates across litter types during the first 2 months of the decomposition process. After 6 months of the decomposition, soil moisture was found to be the key determinant positively affecting mass loss rates. In sum, our research contributes to a better understanding of the determinants of decomposition and shows an important pathway in which tree species diversity affects decomposition, via modified microenvironmental conditions acting via the soil, microclimate and throughfall.
PubDate: 2024-06-01
DOI: 10.1007/s10021-024-00903-2
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- Bioturbation by Benthic Stingrays Alters the Biogeomorphology of Tidal
Flats-
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Abstract: Abstract Fishing-down-marine-food-webs has resulted in alarming declines of various species worldwide. Benthic rays are one examples of such overexploited species. On tidal flats, these rays are highly abundant and play an ecologically important role. They use tidal flats as refuge, feeding and resting grounds, during which they bury into the sediment, which results in sediment bioturbation. Changes in bioturbation intensity, following ray removal, may affect the biogeomorphology of tidal flats with possible cascading effects on the macrozoobenthic community. However, it is poorly understood how these indirect effects could influence ecosystem function. We therefore studied the geomorphic impact of benthic rays (specifically the pearl whipray/stingray Fontitrygon margaritella) on the tropical tidal flats of the Bijagós Archipelago, Guinea-Bissau, on a landscape scale. We investigated 1) bioturbation rates by rays using drone and ground surveys, 2) the spatial distribution of ray pits on multiple tidal flats, 3) the impact of rays on sediment properties and macrozoobenthos by experimental exclusion (15 months). Benthic rays bioturbated 3.7 ± 0.35% of the tidal flat’s sediment surface per day over one single 24-h period, which equals a complete top-sediment-surface turnover every 27 days. The spatial distribution of ray pits was affected by tidal flat geomorphology since pits decayed faster at areas exposed to strong hydrodynamic forces. Predator exclusion altered sediment properties, leading to changes in sedimentation (− 17%) and erosion (− 43%) rates. In addition, macrozoobenthic species composition changed, marked by an increase in Capitellidae worms and a greater biomass of Malacostraca over time. These changes indicated substantial effects of ray bioturbation on the biotic and geomorphic landscape of tidal flats. Overall, we conclude that changing abundances of benthic rays can have clear landscape-wide geomorphological effects on intertidal ecosystems. These indirect consequences of fisheries should be incorporated in integrative management plans to preserve tidal flats and connected ecosystems.
PubDate: 2024-06-01
DOI: 10.1007/s10021-024-00901-4
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- Linking Post-fire Tree Density to Carbon Storage in High-Latitude Cajander
Larch (Larix cajanderi) Forests of Far Northeastern Siberia-
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Abstract: Abstract With climate warming and drying, fire activity is increasing in Cajander larch (Larix cajanderi Mayr.) forests underlain by continuous permafrost in northeastern Siberia, and initial post-fire tree demographic processes could unfold to determine long-term forest carbon (C) dynamics through impacts on tree density. Here, we evaluated above- and belowground C pools across 25 even-aged larch stands of varying tree densities that established following a wildfire in ~ 1940 near Cherskiy, Russia. Total C pools increased with increased larch tree density, from ~ 9,000 g C m−2 in low-density stands to ~ 11,000 g C m−2 in high and very high-density stands, with increases most pronounced at tree densities < 1 stem m−2 and driven by increased above- and belowground (that is, coarse roots) and live and dead (that is, woody debris and snags) larch biomass. Total understory vegetation and non-larch coarse root C pools declined with increased tree density due to decreased shrub C pools, but these pools were relatively small compared to larch biomass. Fine root, soil organic matter (OM), and near surface (0–30 cm) mineral soil (MS) C pools varied little with tree density, although soil C pools held most (18–28% in OM and 44–51% in MS) C stored in these stands. Thus, if changing fire regimes promote denser stands, C storage will likely increase, but whether this increase offsets C lost during fires remains unknown. Our findings highlight how post-fire tree demographic processes impact C pool distribution and stability in larch forests of Siberian permafrost regions.
PubDate: 2024-05-28
DOI: 10.1007/s10021-024-00913-0
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- Wind as a Driver of Peat CO2 Dynamics in a Northern Bog
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Abstract: Abstract Excess CO2 accumulated in soils is typically transported to the atmosphere through molecular diffusion along a concentration gradient. Because of the slow and constant nature of this process, a steady state between peat CO2 production and emissions is often established. However, in peatland ecosystems, high peat porosity could foster additional non-diffusive transport processes, whose dynamics may become important to peat CO2 storage, transport and emission. Based on a continuous record of in situ peat pore CO2 concentration within the unsaturated zone of a raised bog in southern Canada, we show that changes in wind speed create large diel fluctuations in peat pore CO2 store. Peat CO2 builds up overnight and is regularly flushed out the following morning. Persistently high wind speed during the day maintains the peat CO2 with concentrations close to that of the ambient air. At night, wind speed decreases and CO2 production overtakes the transport rate leading to the accumulation of CO2 in the peat. Our results indicate that the effective diffusion coefficient fluctuates based on wind speed and generally exceeds the estimated molecular diffusion coefficient. The balance between peat CO2 accumulation and transport is most dynamic within the range of 0–2 m s−1 wind speeds, which occurs over 75% of the growing season and dominates night-time measurements. Wind therefore drives considerable temporal dynamics in peat CO2 transport and storage, particularly over sub-daily timescales, such that peat CO2 emissions can only be directly related to biological production over longer timescales.
PubDate: 2024-05-23
DOI: 10.1007/s10021-024-00904-1
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- Anthropogenic Eutrophication Drives Major Food Web Changes in Mwanza Gulf,
Lake Victoria-
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Abstract: Abstract Discerning ecosystem change and food web dynamics underlying anthropogenic eutrophication and the introduction of non-native species is necessary for ensuring the long-term sustainability of fisheries and lake biodiversity. Previous studies of eutrophication in Lake Victoria, eastern Africa, have focused on the loss of endemic fish biodiversity over the past several decades, but changes in the plankton communities over this same time remain unclear. To fill this gap, we examined sediment cores from a eutrophic embayment, Mwanza Gulf, to determine the timing and magnitude of changes in the phytoplankton and zooplankton assemblages over the past century. Biogeochemical proxies indicate nutrient enrichment began around ~ 1920 CE and led to rapid increases in primary production, and our analysis of photosynthetic pigments revealed three zones: pre-eutrophication (prior to 1920 CE), onset of eutrophication with increases in all pigments (1920–1990 CE), and sustained eutrophication with cyanobacterial dominance (1990 CE–present). Cladoceran remains indicate an abrupt decline in biomass in ~ 1960 CE, in response to the cumulative effects of eutrophication and lake-level rise, preceding the collapse of haplochromine cichlids in the 1980s. Alona and Chydorus, typically benthic littoral taxa, have remained at relatively low abundances since the 1960s, whereas the abundance of Bosmina, typically a planktonic taxon, increased in the 1990s concurrently with the biomass recovery of haplochromine cichlid fishes. Overall, our results demonstrate substantial changes over the past century in the biomass structure and taxonomic composition of Mwanza Gulf phytoplankton and zooplankton communities, providing a historical food web perspective that can help understand the recent changes and inform future resource management decisions in the Lake Victoria ecosystem.
PubDate: 2024-05-13
DOI: 10.1007/s10021-024-00908-x
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- Disentangling Ecosystem Necromass Dynamics for Biodiversity Conservation
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Abstract: Abstract Global environmental change has redistributed earth’s biomass and the inputs and dynamics of basal detrital resources in ecosystems, contributing to the decline of biodiversity. Yet efforts to manage detrital necromass for biodiversity conservation are often overlooked or consider only singular resource types for focal species groups. We argue there is a significant opportunity to broaden our perspective of the spatiotemporal complexity among multiple necromass types for innovative biodiversity conservation. Here, we introduce an ecosystem-scale perspective to disentangling the spatial and temporal characteristics of multiple and distinct forms of necromass and their associated biota. We show that terrestrial and aquatic ecosystems contain a diversity of necromass types, each with contrasting temporal frequencies and magnitudes, and spatial density and configurations. By conceptualising an ecosystem in this way, we demonstrate that specific necromass dynamics can be identified and targeted for management that benefits the unique spatiotemporal requirements of dependent decomposer organisms and their critical role in ecosystem biomass conversion and nutrient recycling. We encourage conservation practitioners to think about necromass quantity, timing of inputs, spatial dynamics, and to engage with researchers to deepen our knowledge of how necromass might be manipulated to exploit the distinct attributes of different necromass types to help meet biodiversity conservation goals.
PubDate: 2024-04-30
DOI: 10.1007/s10021-024-00907-y
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- Disturbance Level Mediates the Differential Resistance of Tropical Dry
Forest Soil and Vegetation Attributes to High-Intensity Hurricanes-
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Abstract: Abstract Hurricanes are extreme climatic events frequently affecting tropical regions such as the tropical dry forests (TDFs) in Mexico, where its frequency/intensity is expected to increase toward the year 2100. To answer how resistant is a Mexican tropical dry forest to a high-intensity hurricane, and if its degree of resistance was mediated by its conservation degree, we evaluated the effect of a category 4 hurricane over the tree community, soil nutrients, and soil enzymatic activity in two contrasting TDF ecosystems: Old-Growth Forest (OGF) and Secondary Forest (SF). In general, vegetation richness and diversity showed very high resistance one year after the hurricane, but several structural attributes did not, especially in the OGF where the tree mortality related to vegetation structure and spatial distribution of individuals was higher. Then, in the short term, SF vegetation appeared to be more resistant, whereas the OGF, with more biomass to lose, appeared to be more vulnerable. Conversely, most soil attributes showed low resistance in both stages, but especially in SF which could face more severe nutrient limitations. The response of TDF to high-intensity hurricanes, in terms of above- and belowground processes, was in part dependent on its disturbance level. Moreover, an increase in the intensity/frequency of hurricanes could lead this TDF toward a high nutrient limitation (especially by phosphorus) for the plants and consequently toward a loss of soil functioning, especially in the SF. This eventually could produce a severe degradation in fundamental attributes and functions of the ecosystem.
PubDate: 2024-04-02
DOI: 10.1007/s10021-024-00905-0
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