Legacy effects of nitrogen and phosphorus additions on vegetation and carbon stocks of upland heaths
Paassen, José G. van; Britton, Andrea J. ; Mitchell, Ruth J. ; Street, Lorna E. ; Johnson, David ; Coupar, Andrew ; Woodin, Sarah J. - \ 2020
New Phytologist (2020). - ISSN 0028-646X
long term - nitrogen deposition - nutrient cycling - soil - upland heath - vegetation
Soil carbon (C) pools and plant community composition are regulated by nitrogen (N) and phosphorus (P) availability. Atmospheric N deposition impacts ecosystem C storage, but the direction of response varies between systems. Phosphorus limitation may constrain C storage response to N, hence P application to increase plant productivity and thus C sequestration has been suggested. We revisited a 23-yr-old field experiment where N and P had been applied to upland heath, a widespread habitat supporting large soil C stocks. At 10 yr after the last nutrient application we quantified long-term changes in vegetation composition and in soil and vegetation C and P stocks. Nitrogen addition, particularly when combined with P, strongly influenced vegetation composition, favouring grasses over Calluna vulgaris, and led to a reduction in vegetation C stocks. However, soil C stocks did not respond to nutrient treatments. We found 40% of the added P had accumulated in the soil. This study showed persistent effects of N and N + P on vegetation composition, whereas effects of P alone were small and showed recovery. We found no indication that P application could mitigate the effects of N on vegetation or increase C sequestration in this system.
Soil eutrophication shaped the composition of pollinator assemblages during the past century
Carvalheiro, Luísa G. ; Biesmeijer, Jacobus C. ; Franzén, Markus ; Aguirre-Gutiérrez, Jesús ; Garibaldi, Lucas A. ; Helm, Aveliina ; Michez, Denis ; Pöyry, Juha ; Reemer, Menno ; Schweiger, Oliver ; Leon van den, Berg ; WallisDeVries, Michiel F. ; Kunin, William E. - \ 2020
Ecography 43 (2020)2. - ISSN 0906-7590 - p. 209 - 221.
extinction debt - herbivory - historical biodiversity changes - nitrogen deposition - nitrophily - pollinator communities
Atmospheric nitrogen deposition and other sources of environmental eutrophication have increased substantially over the past century worldwide, notwithstanding the recent declining trends in Europe. Despite the recognized susceptibility of plants to eutrophication, few studies evaluated how impacts propagate to consumers, such as pollinators. Here we aim to test if soil eutrophication contributes to the temporal dynamics of pollinators and their larval resources. We used a temporally and spatially explicit historical dataset with information on species occurrences to test if soil eutrophication, and more specifically nitrogen deposition, contributes to the patterns of change of plant and pollinator richness in the Netherlands over an 80 yr period. We focus on bees and butterflies, two groups for which we have good knowledge of larval resources that allowed us to define groups of species with different nitrogen related diet preferences. For each group we estimated richness changes between different 20-yr periods at local, regional and national scale, using analytical methods developed for analyzing richness changes based on collection data. Our findings suggest that the impacts of soil eutrophication on plant communities propagate to higher trophic levels, but with a time-lag. Pollinators with nitrogen-related diet preferences were particularly affected, in turn potentially impairing the performance of pollinator-dependent plants. Pollinator declines continued even after their focal plants started to recover. In addition, our results suggest that current levels of nitrogen deposition still have a negative impact on most groups here analyzed, constraining richness recoveries and accentuating declines. Our results indicate that the global increase in nitrogen availability plays an important role in the ongoing pollinator decline. Consequently, species tolerances to soil nitrogen levels should be considered across all trophic levels in management plans that aim to halt biodiversity loss and enhance ecosystems services worldwide.
Nitrogen Deposition Maintains a Positive Effect on Terrestrial Carbon Sequestration in the 21st Century Despite Growing Phosphorus Limitation at Regional Scales
Fleischer, Katrin ; Dolman, A.J. ; Molen, Michiel K. van der; Rebel, Karin T. ; Erisman, Jan Willem ; Wassen, Martin J. ; Pak, Bernard ; Lu, Xingjie ; Rammig, Anja ; Wang, Ying Ping - \ 2019
Global Biogeochemical Cycles 33 (2019)6. - ISSN 0886-6236 - p. 810 - 824.
carbon sequestration - land carbon sink - nitrogen deposition - nitrogen fixation - phosphorus limitation - terrestrial ecosystems
Nitrogen (N) and phosphorus (P) are two dominant nutrients regulating the productivity of most terrestrial ecosystems. The growing imbalance of anthropogenic N and P inputs into the future is estimated to exacerbate P limitation on land and limit the land carbon (C) sink, so that we hypothesized that P limitation will increasingly reduce C sequestered per unit N deposited into the future. Using a global land surface model (CABLE), we simulated the effects of increased N deposition with and without P limitation on land C uptake and the fate of deposited N on land from 1901 to 2100. Contrary to our hypothesis, we found that N deposition continued to induce land C sequestration into the future, contributing to 15% of future C sequestration as opposed to 6% over the historical period. P limitation reduced the future land C uptake per unit N deposited only moderately at the global scale but P limitation increasingly caused N deposition to have net negative effects on the land C balance in the temperate zone. P limitation further increased the fraction of deposited N that is lost via leaching to aquatic ecosystems, globally from 38.5% over the historical period to 53% into the future, and up to 75% in tropical ecosystems. Our results suggest continued N demand for plant productivity but also indicate growing adverse N deposition effects in the future biosphere, not fully accounted for in global models, emphasizing the urgent need to elaborate on model representations of N and P dynamics.
Environmental drivers interactively affect individual tree growth across temperate European forests
Maes, Sybryn L. ; Perring, Michael P. ; Vanhellemont, Margot ; Depauw, Leen ; Bulcke, Jan Van den; Brūmelis, Guntis ; Brunet, Jörg ; Decocq, Guillaume ; Ouden, Jan den; Härdtle, Werner ; Hédl, Radim ; Heinken, Thilo ; Heinrichs, Steffi ; Jaroszewicz, Bogdan ; Kopecký, Martin ; Máliš, František ; Wulf, Monika ; Verheyen, Kris - \ 2019
Global Change Biology 25 (2019)1. - ISSN 1354-1013 - p. 201 - 217.
basal area increment - climate change - Fagus - Fraxinus - historical ecology - nitrogen deposition - Quercus - tree-ring analysis
Forecasting the growth of tree species to future environmental changes requires a better understanding of its determinants. Tree growth is known to respond to global-change drivers such as climate change or atmospheric deposition, as well as to local land-use drivers such as forest management. Yet, large geographical scale studies examining interactive growth responses to multiple global-change drivers are relatively scarce and rarely consider management effects. Here, we assessed the interactive effects of three global-change drivers (temperature, precipitation and nitrogen deposition) on individual tree growth of three study species (Quercus robur/petraea, Fagus sylvatica and Fraxinus excelsior). We sampled trees along spatial environmental gradients across Europe and accounted for the effects of management for Quercus. We collected increment cores from 267 trees distributed over 151 plots in 19 forest regions and characterized their neighbouring environment to take into account potentially confounding factors such as tree size, competition, soil conditions and elevation. We demonstrate that growth responds interactively to global-change drivers, with species-specific sensitivities to the combined factors. Simultaneously high levels of precipitation and deposition benefited Fraxinus, but negatively affected Quercus’ growth, highlighting species-specific interactive tree growth responses to combined drivers. For Fagus, a stronger growth response to higher temperatures was found when precipitation was also higher, illustrating the potential negative effects of drought stress under warming for this species. Furthermore, we show that past forest management can modulate the effects of changing temperatures on Quercus’ growth; individuals in plots with a coppicing history showed stronger growth responses to higher temperatures. Overall, our findings highlight how tree growth can be interactively determined by global-change drivers, and how these growth responses might be modulated by past forest management. By showing future growth changes for scenarios of environmental change, we stress the importance of considering multiple drivers, including past management and their interactions, when predicting tree growth.
Low historical nitrogen deposition effect on carbon sequestration in the boreal zone
Fleischer, K. ; Wårlind, D. ; Molen, M.K. Van Der; Rebel, K.T. ; Arneth, A. ; Erisman, J.W. ; Wassen, M.J. ; Smith, B. ; Gough, C.M. ; Margolis, H.A. ; Cescatti, A. ; Montagnani, L. ; Arain, A. ; Dolman, A.J. - \ 2015
Journal of Geophysical Research: Biogeosciences 120 (2015)12. - ISSN 2169-8953 - p. 2542 - 2561.
carbon sequestration - FLUXNET - forests - global dynamic vegetation models - nitrogen deposition
Nitrogen (N) cycle dynamics and N deposition play an important role in determining the terrestrial biosphere's carbon (C) balance. We assess global and biome-specific N deposition effects on C sequestration rates with the dynamic global vegetation model LPJ-GUESS. Modeled CN interactions are evaluated by comparing predictions of the C and CN version of the model with direct observations of C fluxes from 68 forest FLUXNET sites. N limitation on C uptake reduced overestimation of gross primary productivity for boreal evergreen needleleaf forests from 56% to 18%, presenting the greatest improvement among forest types. Relative N deposition effects on C sequestration (dC/dN) in boreal, temperate, and tropical sites ranged from 17 to 26 kg C kg N-1 when modeled at site scale and were reduced to 12-22 kg C kg N-1 at global scale. We find that 19% of the recent (1990-2007) and 24% of the historical global C sink (1900-2006) was driven by N deposition effects. While boreal forests exhibit highest dC/dN, their N deposition-induced C sink was relatively low and is suspected to stay low in the future as no major changes in N deposition rates are expected in the boreal zone. N deposition induced a greater C sink in temperate and tropical forests, while predicted C fluxes and N-induced C sink response in tropical forests were associated with greatest uncertainties. Future work should be directed at improving the ability of LPJ-GUESS and other process-based ecosystem models to reproduce C cycle dynamics in the tropics, facilitated by more benchmarking data sets. Furthermore, efforts should aim to improve understanding and model representations of N availability (e.g., N fixation and organic N uptake), N limitation, P cycle dynamics, and effects of anthropogenic land use and land cover changes.
Spatial boundary of urban ‘acid islands’ in China
Du, E. ; Vries, W. de; Liu, X. ; Fang, J. ; Galloway, J.N. ; Jiang, Y. - \ 2015
Scientific Reports 5 (2015). - ISSN 2045-2322 - 9 p.
atmospheric deposition - nitrogen deposition - air-pollution - soil acidification - emissions - canopy - forest - rain - ecosystems - cities
Elevated emissions of sulfur dioxide, nitrogen oxides and ammonia in China have resulted in high levels of sulfur and nitrogen deposition, being contributors to soil acidification, especially in and near large cities. However, knowledge gaps still exist in the way that large cities shape spatial patterns of acid deposition. Here, we assessed the patterns of pH, sulfate, nitrate and ammonium in bulk precipitation and throughfall in southern China’s forests by synthesizing data from published literature. Concentrations and fluxes of sulfate, nitrate and ammonium in bulk precipitation and throughfall exhibited a power-law increase with a closer distance to the nearest large cities, and accordingly pH showed a logarithmic decline. Our findings indicate the occurrence of urban ‘acid islands’ with a critical radius of approximately 70¿km in southern China, receiving potential acid loads of more than 2 keq ha-1 yr-1. These urban acid islands covered an area of 0.70¿million km2, accounting for nearly 30% of the land area in southern China. Despite a significant capacity to neutralize acids in precipitation, our analysis highlights a substantial contribution of ammonium to potential acid load. Our results suggest a joint control on emissions of multiple acid precursors from urban areas in southern China
Intercropping affects the rate of decomposition of soil organic matter and root litter
Cong, W. ; Hoffland, E. ; Li, L. ; Janssen, B.H. ; Werf, W. van der - \ 2015
Plant and Soil 391 (2015)1-2. - ISSN 0032-079X - p. 399 - 411.
plant-species richness - experimental grassland ecosystems - nitrogen deposition - northwest china - elevated co2 - diversity - biodiversity - mineralization - rhizosphere - carbon
Aims - Intercropping increases aboveground and belowground crop productivity, suggesting potential for carbon sequestration. Here we determined whether intercropping affects decomposition of soil organic matter (SOM) and root litter. Methods - We measured in the laboratory and the field the breakdown of SOM, root litter of maize, wheat, or faba bean, litter mixtures, and a standard substrate (compost) in soils from a long term intercropping experiment. Results - Soil organic matter from intercrop plots decomposed faster than SOM from monocrop plots, but compost decomposed at similar rates in different soils. Faster SOM decomposition was associated with lower soil C:N ratio. Root litter mixtures of maize and wheat decomposed as expected from single litters, but litter mixture of maize and faba bean decomposed faster than expected, both in the laboratory and in the field. Root litter decomposed slowly in maize/wheat intercrop soil compared to the two monocropped soils in the laboratory, but the effect was absent in the field. Conclusions - Intercropping increases SOM decomposition, presumably through reduced SOM recalcitrance resulting from lower C:N ratio, higher litter input and better N retention. Depending on the crop combination, also non-additive effects of root litter mixing can enhance organic matter decomposition in intercropping soils.
Restoration of acidified and eutrophied rich fens: Long-term effects of traditional management and experimental liming
Diggelen, J. van; Bense, I.H.M. ; Brouwer, E. ; Limpens, J. ; Schie, J.M. van; Smolders, A.J.P. ; Lamers, L.P.M. - \ 2015
Ecological Engineering 75 (2015). - ISSN 0925-8574 - p. 208 - 216.
laagveengebieden - eutrofiëring - verzuring - ecologisch herstel - bekalking - fens - eutrophication - acidification - ecological restoration - liming - vegetation development - nutrient availability - nitrogen deposition - surface-water - groundwater - phosphorus - level - limitation - wetlands
Rich fens are known for their high botanical diversity encompassing many endangered species. For decades, several management measures, including mowing and burning, have been applied to maintain a high biodiversity by means of slowing down the natural succession from calcareous rich fens to acidic poor fens or woodland. In this study, we assessed the long-term effects of these traditional management measures, and explored the effectiveness of liming as a measure to restore rich fen vegetation. Effects of summer mowing, and of burning after winter mowing, were assessed by comparing current (2013) and historical (1967) vegetation data. Effects of experimental liming, using different levels of lime addition (0, 1000, 2000, and 4000 kg Dolokal/ha), were monitored in the field during 7.5 years. Summer mowing led to more acidic and nutrient-poor conditions as indicated by a shift from rich to poor fen vegetation, including a well-developed bryophyte cover dominated by Sphagnum with some threatened species. Burning (after winter mowing) counteracted acidification but increased nutrient availability, as indicated by dominance of vascular species characteristic of productive tall-herb grasslands and a sparse bryophyte cover with common species. We conclude that the traditional measures were unable to maintain rich fen composition in the long term. Given the fact that the restoration of hydrological conditions, favouring rich fens, is not always feasible, liming could be an alternative to counteract acidification and improve rich fen conditions in the short term. This measure, however, appeared to be unsustainable as the re-establishment and dominance of Sphagnum spp. seriously complicated the development of rich fen vegetation in the longer term.
The Critical Loads and Levels Approach for Nitrogen
Clair, T.A. ; Blett, T. ; Aherne, J. ; Dobben, H.F. van - \ 2014
In: Nitrogen Deposition, Critical Loads and Biodiversity / Sutton, Mark A., Mason, Kate E., Sheppard, Lucy J., Sverdrup, Harald, Haeuber, Richard, Hicks, W. Kevin, Dordrecht : Springer Verlag - ISBN 9789400779389 - p. 481 - 491.
critical loads - empirical - Exceedance - Modelling - nitrogen deposition
This chapter reports the findings of a Working Group on how atmospheric nitrogen (N) deposition affects both terrestrial and freshwater biodiversity. Regional and global scale impacts on biodiversity are addressed, together with potential indicators. Key conclusions are that: the rates of loss in biodiversity are greatest at the lowest and initial stages of N deposition increase; changes in species compositions are related to the relative amounts of N, carbon (C) and phosphorus (P) in the plant soil system; enhanced N inputs have implications for C cycling; N deposition is known to be having adverse effects on European and North American vegetation composition; very little is known about tropical ecosystem responses, while tropical ecosystems are major biodiversity hotspots and are increasingly recipients of very high N deposition rates; N deposition alters forest fungi and mycorrhyzal relations with plants; the rapid response of forest fungi and arthropods makes them good indicators of change; predictive tools (models) that address ecosystem scale processes are necessary to address complex drivers and responses, including the integration of N deposition, climate change and land use effects; criteria can be identified for projecting sensitivity of terrestrial and aquatic ecosystems to N deposition. Future research and policy-relevant recommendations are identified.
Why Some Plant Species Are Rare
Weiger Wamelink, G.W. ; Goedhart, P.W. ; Frissel, J.Y. - \ 2014
PLoS ONE 9 (2014)10. - ISSN 1932-6203 - 7 p.
grassland vegetation - nitrogen deposition - biodiversity - diversity - predictors - habitats - declines - climate - ranges - common
Biodiversity, including plant species diversity, is threatened worldwide as a result of anthropogenic pressures such as an increase of pollutants and climate change. Rare species in particular are on the verge of becoming extinct. It is still unclear as to why some plant species are rare and others are not. Are they rare due to: intrinsic reasons, dispersal capacity, the effects of management or abiotic circumstances? Habitat preference of rare plant species may play an important role in determining why some species are rare. Based on an extensive data set of soil parameters we investigated if rarity is due to a narrow habitat preference for abiotic soil parameters. For 23 different abiotic soil parameters, of which the most influential were groundwater-table, soil-pH and nutrient-contents, we estimated species responses for common and rare species. Based on the responses per species we calculated the range of occurrence, the range between the 5 and 95 percentile of the response curve giving the habitat preference. Subsequently, we calculated the average response range for common and rare species. In addition, we designed a new graphic in order to provide a better means for presentation of the results. The habitat preferences of rare species for abiotic soil conditions are significantly narrower than for common species. Twenty of the twenty-three abiotic parameters showed on average significantly narrower habitat preferences for rare species than for common species; none of the abiotic parameters showed on average a narrower habitat preference for common species. The results have major implications for the conservation of rare plant species; accordingly management and nature development should be focussed on the maintenance and creation of a broad range of environmental conditions, so that the requirements of rare species are met. The conservation of (abiotic) gradients within ecosystems is particularly important for preserving rare species.
Aboveground persistence of vascular plants in relationship to the levels of airborne nutrient deposition
Hendriks, R.J.J. ; Ozinga, W.A. ; Berg, L.J.L. van den; Noordwijk, E. ; Schaminee, J.H.J. ; Groenendael, J.M. van - \ 2014
Plant Ecology 215 (2014)11. - ISSN 1385-0237 - p. 1277 - 1286.
nitrogen deposition - constraints - impact
This paper examines whether high atmospheric nitrogen deposition affects aboveground persistence of vascular plants. We combined information on local aboveground persistence of vascular plants in 245 permanent plots in the Netherlands with estimated level of nitrogen deposition at the time of recording. Aboveground persistence of vascular plants was studied using two types of survival statistic technique: Kaplan–Meier analysis and Cox’ regression. We expected a link between nitrogen deposition and loss of plant species due to intensified herbivory or other forms of tissue loss that would lead to diminishing local aboveground persistence. This could not be detected. In contrast, a positive relation was found between local aboveground persistence of plants and high levels of ammonia deposition. This result is considered to be an indication of lower colonization access, for example due to limited space (e.g. the chance of successful establishment of individuals from new species is lower). The results are discussed in relation to the extremely high levels of nitrogen deposition in the studied plots. This study provides an indication that management practices aiming for restoration of colonization access (e.g. mowing, grazing and sod cutting) are vital under heavily eutrophied conditions.
Linking species assemblages to environmental change: Moving beyond the specialist-generalist dichotomy
Wallis de Vries, M.F. - \ 2014
Basic and Applied Ecology 15 (2014)4. - ISSN 1439-1791 - p. 279 - 287.
british butterflies - habitat fragmentation - biotic homogenization - nitrogen deposition - climate-change - conservation - diversity - responses - richness - traits
Environmental changes due to land use developments, climate change and nitrogen deposition have profound influences on species assemblages. Investigating the dynamics in species composition as a function of underlying traits may increase our understanding of ecosystem functioning and provide a basis for effective conservation strategies. Here, I use a broad array of species traits for butterflies to identify four main components of associated traits. These reflect the spatial use of the landscape, abiotic vulnerability, developmental rate and phenology, and food specialisation, respectively. The first three trait components each contribute to determine Red List status, but only the developmental rate and phenology component is related to recent population trends. I argue that the latter component reflects the environmental impact of nutrient availability and microclimate, as affected by nitrogen deposition. This perspective sheds a new light on ongoing changes in community composition. Thus, a multidimensional view of trait associations allows us to move beyond the simplistic specialist–generalist dichotomy, renew our view on species-specific studies and help in setting new priorities for conservation.
Habitat selection of brood-rearing Northern Wheatears Oenanthe oenanthe and their invertebrate prey
Oosten, H. van; Burg, A.B. Van den; Versluijs, R. ; Siepel, H. - \ 2014
Ardea 102 (2014)1. - ISSN 0373-2266 - p. 61 - 69.
assemblage structure - nitrogen deposition - species richness - plant diversity - home-range - grasslands - conservation - communities - arthropods - migration
Birds consider both variation in prey abundance and accessibility in their decision of where to forage. Acidification and nitrogen deposition affect both prey abundance and accessibility by stimulating growth of nitrophilic grasses at the expense of forbs. Management practises such as mowing or grazing primarily affect vegetation structure which also influences the abundance and accessibility of invertebrates. Hence, for effective management and conservation purposes It is paramount to understand the relationships between vegetation structure, densities of preferred prey and habitat-use of birds. In this study we explore such relationships for the nationally endangered Northern Wheatear Oenanthe oenanthe in dune grasslands along the Dutch coast. Our findings support the hypothesis that forager mobility and food accessibility are of greater importance during patch selection than food abundance per se in ground foraging birds. The abundance of all potential prey and three of the four most important actual prey groups was highest in tall grass, but Northern Wheatears foraged preferentially in short grass. Clearly, encroachment by tall grass will diminish habitat suitability for Northern Wheatears due to lowered prey accessibility. We propose that a mixture of short and tall vegetation and landscape management allows for dispersal of arthropods between different (micro)habitats. We provide densities of the important prey in a coastal area where Northern Wheatears still successfully breed. This enables site-managers to efficiently investigate presence and abundance of important prey In seemingly suitable areas but where Northern Wheatears do not breed. Eventually we may be able to discern whether food shortage poses a bottleneck for Northern Wheatears in these uninhabited areas.
Plant movements and climate warming: intraspecific variation in growth responses to nonlocal soils
Frenne, P. De; Coomes, D. ; Schrijver, A. De; Staelens, J. ; Alexander, J.M. ; Bernhardt-Romermann, M. ; Brunet, J. ; Chabrerie, O. ; Chiarucci, A. ; Ouden, J. den - \ 2014
New Phytologist 202 (2014)2. - ISSN 0028-646X - p. 431 - 441.
local adaptation - latitudinal gradient - vascular plants - forest herbs - nitrogen deposition - seed dispersal - range shifts - germination - colonization - temperature
Most range shift predictions focus on the dispersal phase of the colonization process. Because moving populations experience increasingly dissimilar nonclimatic environmental conditions as they track climate warming, it is also critical to test how individuals originating from contrasting thermal environments can establish in nonlocal sites. We assess the intraspecific variation in growth responses to nonlocal soils by planting a widespread grass of deciduous forests (Milium effusum) into an experimental common garden using combinations of seeds and soil sampled in 22 sites across its distributional range, and reflecting movement scenarios of up to 1600 km. Furthermore, to determine temperature and forest-structural effects, the plants and soils were experimentally warmed and shaded. We found significantly positive effects of the difference between the temperature of the sites of seed and soil collection on growth and seedling emergence rates. Migrant plants might thus encounter increasingly favourable soil conditions while tracking the isotherms towards currently ‘colder’ soils. These effects persisted under experimental warming. Rising temperatures and light availability generally enhanced plant performance. Our results suggest that abiotic and biotic soil characteristics can shape climate change-driven plant movements by affecting growth of nonlocal migrants, a mechanism which should be integrated into predictions of future range shifts.
Expansion of acidophytic late-successional bryophytes in Dutch fens between 1940 and 2000
Paulissen, M.P.C.P. ; Schaminee, J.H.J. ; During, H.J. ; Wamelink, G.W.W. ; Verhoeven, J.T.A. - \ 2014
Journal of Vegetation Science 25 (2014)2. - ISSN 1100-9233 - p. 525 - 533.
nitrogen deposition - co westmeath - scragh-bog - vegetation - mire - acidification - netherlands - ammonium - water - metaanalyses
Question How did frequency and local abundance of key bryophytes in Dutch fens change between 1940 and 2000? Location The Netherlands. Methods A total of 1939 vegetation relevés, objectively assigned to the class Parvocaricetea and dating from the period 1940–1999 inclusive, were extracted from a national Netherlands database. From this relevé set, two additional data sets were derived; these were syntaxonomically homogeneous at the association level. One contained 418 Scorpidio-Caricetum diandrae relevés and the other 956 Pallavicinio-Sphagnetum relevés. The following analyses were done for these three data sets: frequency and local abundance change of 13 bryophyte species over three 20-yr periods were described using logistic regression and the nonparametric Jonckheere–Terpstra test, respectively. Results Acidophytic, late-successional species, notably Sphagnum palustre and Polytrichum uliginosum, have replaced relatively early-successional species such as brown mosses, Sphagnum subnitens and Sphagnum squarrosum during the studied period. The results were mostly consistent across the three data sets. Local abundance patterns generally paralleled those of frequency, although cover trends were often less robust. Conclusions Drastic changes have taken place in the bryophyte layer of Dutch fens between 1940 and 2000. Our study has shown that acidophytic, late-successional bryophytes have replaced relatively early-successional brown moss and Sphagnum species. Both hydrological changes and nutrient shifts (in particular phosphorus enrichment and ammonium toxicity) appear to have been responsible for the observed rapid shifts in the bryophyte layer of Dutch fens.
A thready affair: linking fungal diversity and community dynamics to terrestrial decomposition processes
Wal, A. van der; Geydan Rivera, T.D.K.H. ; Kuyper, T.W. ; Boer, W. de - \ 2013
FEMS Microbiology Reviews 37 (2013)4. - ISSN 0168-6445 - p. 477 - 494.
soil organic-matter - leaf-litter decomposition - wood-decaying fungi - home-field advantage - white-rot fungi - microbial community - temperature sensitivity - functional diversity - nitrogen deposition - active fungi
Filamentous fungi are critical to the decomposition of terrestrial organic matter and, consequently, in the global carbon cycle. In particular, their contribution to degradation of recalcitrant lignocellulose complexes has been widely studied. In this review, we focus on the functioning of terrestrial fungal decomposers and examine the factors that affect their activities and community dynamics. In relation to this, impacts of global warming and increased N deposition are discussed. We also address the contribution of fungal decomposer studies to the development of general community ecological concepts such as diversity-functioning relationships, succession, priority effects and home-field advantage. Finally, we indicate several research directions that will lead to a more complete understanding of the ecological roles of terrestrial decomposer fungi such as their importance in turnover of rhizodeposits, the consequences of interactions with other organisms and niche differentiation.
Considerable environmental bottlenecks for species listed in the Habitats and Birds Directives in the Netherlands
Wamelink, G.W.W. ; Knegt, B. de; Pouwels, R. ; Schuiling, C. ; Wegman, R.M.A. ; Schmidt, A.M. ; Dobben, H.F. van; Sanders, M.E. - \ 2013
Biological Conservation 165 (2013)sept.. - ISSN 0006-3207 - p. 43 - 53.
nitrogen deposition - climate-change - changing biodiversity - provide connectivity - critical loads - large mammals - global change - vegetation - consequences - ecosystem
Many habitats and species have their existence threatened, especially in densely populated areas such as Western Europe. To stop the decline of biodiversity, the Natura 2000 network is being set-up. The ultimate objective is to get all habitat types (of Annex I of the Habitats Directive) and species (of Annexes II, III and IV of the Habitats Directive and Annex I of the Birds Directive) in a favourable conservation status. In the Netherlands a national ecological network has been set up for this purpose which includes the designated Natura 2000 sites. The current amount of atmospheric nitrogen deposition, acidification and desiccation were compared with limit values per habitat type for nitrogen deposition load, soil pH and spring groundwater table respectively and subsequently presented together in one map. Fragmentation was tested for 80 species.For two-third of the examined natural surface the critical load for nitrogen deposition is exceeded, desiccation is present in over 90% of the area of groundwater dependent nature. Problems with acidification are less pronounced. Fragmentation is present causing regional problems for up to six species. When the four pressures are combined, about two third of the areas suffer from at least one pressure. Many areas suffer from a combination of nitrogen deposition and desiccation.We conclude that environmental and spatial conditions are insufficient to meet the biodiversity target set by the European Union for the Natura 2000 network, habitat types and species.
Plant quality and local adaptation undermine relocation in a bog specialist butterfly
Turlure, C. ; Radchuk, V. ; Baguette, M. ; Meijrink, M. ; Burg, A. van den; Wallis de Vries, M.F. ; Duinen, G.J. - \ 2013
Ecology and Evolution 3 (2013)2. - ISSN 2045-7758 - p. 244 - 254.
nitrogen deposition - phenotypic plasticity - climate-change - reintroduction biology - conservation - habitat - lepidoptera - diversity - selection - dynamics
The butterfly Boloria aquilonaris is a specialist of oligotrophic ecosystems. Population viability analysis predicted the species to be stable in Belgium and to collapse in the Netherlands with reduced host plant quality expected to drive species decline in the latter. We tested this hypothesis by rearing B. aquilonaris caterpillars from Belgian and Dutch sites on host plants (the cranberry, Vaccinium oxycoccos). Dutch plant quality was lower than Belgian one conferring lower caterpillar growth rate and survival. Reintroduction and/or supplementation may be necessary to ensure the viability of the species in the Netherlands, but some traits may have been selected solely in Dutch caterpillars to cope with gradual changes in host plant quality. To test this hypothesis, the performance of Belgian and Dutch caterpillars fed with plants from both countries were compared. Dutch caterpillars performed well on both plant qualities, whereas Belgian caterpillars could not switch to lower quality plants. This can be considered as an environmentally induced plastic response of caterpillars and/or a local adaptation to plant quality, which precludes the use of Belgian individuals as a unique solution for strengthening Dutch populations. More generally, these results stress that the relevance of local adaptation in selecting source populations for relocation may be as important as restoring habitat quality.
A meta-database comparison from various European research networks dedicated to forests sites
Danielewska, A. ; Clarke, N. ; Olejnik, J. ; Hansen, K. ; Vries, W. de - \ 2013
iForest : Biogeosciences and Forestry 6 (2013). - ISSN 1971-7458 - p. 1 - 9.
nitrogen deposition - terrestrial ecosystems - anthropogenic sources - air-pollutants - climate-change - united-states - heavy-metals - carbon - ozone - pollution
Of a wide variety of international forest research and monitoring networks, several networks are dedicated to the effects of climate change on forests, while the effects of anthropogenic pollutants on forests have been a major area for both monitoring and research for decades. The large amounts of data already obtained within existing monitoring programmes and large-scale international projects can be used to increase understanding of the state and potential of forest mitigation and adaptation to climate change in a polluted environment, and a major challenge now is to evaluate and integrate the presently available databases. We present a meta-database with the main goal to highlight available data and integrate the information about research and monitoring of selected European Research and Monitoring Networks (ERMNs). Depending on the selected ERMNs, the list of variables and the measurement units differ widely in the databases. As a result, activities related to the identification, evaluation and integration of the presently available databases are important for the scientific community. Furthermore, and equally important, the recognition of current knowledge gaps and future needed research is made easier. This analysis suggests that: ground-level ozone is under-investigated, although it is one of the pollutants of greatest concern to forests; in addition to CO2, long-term other greenhouse gasses (GHG) flux measurements should be carried out; there is still a need of improving links between monitoring of atmospheric changes and impacts on forests; research-oriented manipulative experiments in the forests are missing.
Driving factors behind the eutrophication signal in understorey plant communities of deciduous temperate forests
Verheyen, K. ; Baeten, L. ; Frenne, P. De; Bernhardt-Römermann, M. ; Brunet, J. ; Cornelis, J. ; Decocq, G. ; Eriksson, O. ; Dierschke, H. ; Hommel, P.W.F.M. - \ 2012
Journal of Ecology 100 (2012)2. - ISSN 0022-0477 - p. 352 - 365.
coppice-with-standards - ellenberg indicator values - ground-layer vegetation - white-tailed deer - nitrogen deposition - leaf-litter - species richness - atmospheric deposition - soil acidification - field-measurements
1. Atmospheric nitrogen (N) deposition is expected to change forest understorey plant community composition and diversity, but results of experimental addition studies and observational studies are not yet conclusive. A shortcoming of observational studies, which are generally based on resurveys or sampling along large deposition gradients, is the occurrence of temporal or spatial confounding factors. 2. We were able to assess the contribution of N deposition versus other ecological drivers on forest understorey plant communities by combining a temporal and spatial approach. Data from 1205 (semi-)permanent vegetation plots taken from 23 rigorously selected understorey resurvey studies along a large deposition gradient across deciduous temperate forest in Europe were compiled and related to various local and regional driving factors, including the rate of atmospheric N deposition, the change in large herbivore densities and the change in canopy cover and composition. 3. Although no directional change in species richness occurred, there was considerable floristic turnover in the understorey plant community and a shift in species composition towards more shade-tolerant and nutrient-demanding species. However, atmospheric N deposition was not important in explaining the observed eutrophication signal. This signal seemed mainly related to a shift towards a denser canopy cover and a changed canopy species composition with a higher share of species with more easily decomposed litter. 4. Synthesis. Our multi-site approach clearly demonstrates that one should be cautious when drawing conclusions about the impact of atmospheric N deposition based on the interpretation of plant community shifts in single sites or regions due to other, concurrent, ecological changes. Even though the effects of chronically increased N deposition on the forest plant communities are apparently obscured by the effects of canopy changes, the accumulated N might still have a significant impact. However, more research is needed to assess whether this N time bomb will indeed explode when canopies will open up again.