Evaluating the ecological realism of plant species distribution models with ecological indicator values

Species distribution models (SDMs) are routinely applied to assess current as well as future species distributions, for example to assess impacts of future environmental change on biodiversity or to underpin conservation planning. It has been repeatedly emphasized that SDMs should be evaluated based not only on their goodness of fit to the data, but also on the realism of the modelled ecological responses. However, possibilities for the latter are hampered by limited knowledge on the true responses as well as a lack of quantitative evaluation methods. Here we compared modelled niche optima obtained from European-scale SDMs of 1,476 terrestrial vascular plant species with empirical ecological indicator values indicating the preferences of plant species for key environmental conditions. For each plant species we first fitted an ensemble SDM including three modeling techniques (GLM, GAM and BRT) and extracted niche optima for climate, soil, land use and nitrogen deposition variables with a large explanatory power for the occurrence of that species. We then compared these SDM-derived niche optima with the ecological indicator values by means of bivariate correlation analysis. We found weak to moderate correlations in the expected direction between the SDM-derived niche optima and ecological indicator values. The strongest correlation occurred between the modelled optima for growing degree days and the ecological indicator values for temperature. Correlations were weaker for SDM-derived niche optima with a more distal relationship to ecological indicator values (notably precipitation and soil moisture). Further, correlations were consistently highest for BRT, followed by GLM and GAM. Our method gives insight into the ecological realism of modelled niche optima and projected core habitats and can be used to improve SDMs by making a more informed selection of environmental variables and modeling techniques

Changes of nitrogen deposition in China from 1980 to 2018

China has experienced a dramatic change in atmospheric reactive nitrogen (Nr) emissions over the past four decades. However, it remains unclear how nitrogen (N) deposition has responded to increases and/or decreases in Nr emissions. This study quantitatively assesses temporal and spatial variations in measurements of bulk and calculated dry N deposition in China from 1980 to 2018. A long-term database (1980–2018) shows that bulk N deposition peaked in around 2000, and had declined by 45% by 2016–2018. Recent bulk and dry N deposition (based on monitoring from 2011 to 2018) decreased from 2011 to 2018, with current average values of 19.4 ± 0.8 and 20.6 ± 0.4 kg N ha−1 yr−1, respectively. Oxidized N deposition, especially dry deposition, decreased after 2010 due to NOx emission controls. In contrast, reduced N deposition was approximately constant, with reductions in bulk NH4+-N deposition offset by a continuous increase in dry NH3 deposition. Elevated NH3 concentrations were found at nationwide monitoring sites even at urban sites, suggesting a strong influence of both agricultural and non-agricultural sources. Current emission controls are reducing Nr emissions and deposition but further mitigation measures are needed, especially of NH3, built on broader regional emission control strategies

Technical documentation of the soil model VSD+ : Status A

VSD+ is een model om de gevolgen te berekenen van atmosferische depositie en klimaatverandering voorbodemverzuring, de beschikbaarheid van voedingsstoffen en het vastleggen van koolstof. Het model isontwikkeld ter onderbouwing van strategieën om de uitstoot van zwavel (S) en stikstof (N) in Europa teverminderen. Dit document biedt een samenvatting van de theorie waar het model op gestoeld is, detechnische documentatie hiervan alsmede een beschrijving van het testen, het valideren en de sensitiviteitsanalysevan het model. De processen zoals beschreven in het artikel over VSD+ zijn met goed gevolg getest.De gevoeligheidsanalyse gaf aan dat de constante voor het evenwicht tussen H+ en Al3+ in de bodemoplossingen de Ca-verweringssnelheid de parameters zijn, die voor een groot gedeelte de waarde van degesimuleerde pH bepalen. Voor basenverzadiging zijn de belangrijkste parameters de uitwisselingsconstantetussen H+ en basische kationen en de verwering van Ca. Voor de C/N ratio van bodemorganische stof zijn Cen N in het strooisel en de opname van N zeer bepalende factoren. De nitraatconcentratie hangt sterk samenmet het nerslagoverschot en de netto input van N---VSD+ is a model to calculate effects of atmospheric deposition and climate change on soil acidification,nutrient availability and carbon sequestration. The model has been developed to support emission abatementstrategies of sulphur (S) and nitrogen (N) in Europe. This document contains a summary of the modeltheory, technical documentation and descriptions of testing, validations and the sensitivity analysis of themodel. The processes described in the paper about VSD+ have been tested successfully. The sensitivityanalysis showed that the constant for the equilibrium between H+ and Al3+ in the soil solution and theweathering rate of Ca are the parameters that to a large extent determine the value of the simulated pH. Forbase saturation, most important parameters are the exchange constant between H+ and base cations andthe weathering of Ca. For the C/N ratio of soil organic matter, litterfall of C and N and the uptake of N areimportant influencing factors. The nitrate concentration strongly depends on the leaching flux and the net N inpu

Modelling study of soil C, N and pH response to air pollution and climate change using European LTER site observations

Current climate warming is expected to continue in coming decades, whereas high N deposition may stabilize, in contrast to the clear decrease in S deposition. These pressures have distinctive regional patterns and their resulting impact on soil conditions is modified by local site characteristics. We have applied the VSD+ soil dynamic model to study impacts of deposition and climate change on soil properties, using MetHyd and GrowUp as pre-processors to provide input to VSD+. The single-layer soil model VSD+ accounts for processes of organic C and N turnover, as well as charge and mass balances of elements, cation exchange and base cation weathering. We calibrated VSD+ at 26 ecosystem study sites throughout Europe using observed conditions, and simulated key soil properties: soil solution pH (pH), soil base saturation (BS) and soil organic carbon and nitrogen ratio (C:N) under projected deposition of N and S, and climate warming until 2100. The sites are forested, located in the Mediterranean, forested alpine, Atlantic, continental and boreal regions. They represent the long-term ecological research (LTER) Europe network, including sites of the ICP Forests and ICP Integrated Monitoring (IM) programmes under the UNECE Convention on Long-range Transboundary Air Pollution (LRTAP), providing high quality long-term data on ecosystem response. Simulated future soil conditions improved under projected decrease in deposition and current climate conditions: higher pH, BS and C:N at 21, 16 and 12 of the sites, respectively. When climate change was included in the scenario analysis, the variability of the results increased. Climate warming resulted in higher simulated pH in most cases, and higher BS and C:N in roughly half of the cases. Especially the increase in C:N was more marked with climate warming. The study illustrates the value of LTER sites for applying models to predict soil responses to multiple environmental changes

A model to calculate effects of atmospheric deposition on soil acidification, eutrophication and carbon sequestration

Triggered by the steep decline in sulphur deposition in Europe and North America over the last decades, research and emission reduction policies have shifted from acidification to the effects of nitrogen (N) deposition and climate change on plant species diversity and carbon (C) sequestration in soils and biomass. Consequently, soil-ecosystem models need to include detailed descriptions of C and N processes, and ideally provide output that link to plant species diversity models. We describe an extension of the Very Simple Dynamic (VSD) model, called VSD+, which includes an explicit description of C and N turnover. Model simulations for three forest stands, which differ in N deposition and soil C/N ratios, show that VSD+ can well predict both trends and absolute values of NO3 and NH4 concentrations in soil and stream waters, soil C/N ratios and pH, which makes VSD+ suitable for providing input for plant species diversity models.</p

Critical loads for eutrophication and acidification for European terrestrial ecosystems

The project aimed to improve the European background database used by the Coordination Centre for Effects (CCE) to calculate Critical Loads (CLs) for eutrophication and acidification for (semi-) natural European terrestrial ecosystems. The database is used when member countries do not provide their own CL data to the CCE. In this case, the missing country data are replaced by the results of the background database when the CCE produces European CL maps. This report describes the (a) underlying datasets; (b) derivation of the input data for the CL model; (c) R packages and scripts developed; and (c) verification of the results. These results feed into international and national policy advice, e.g., they are an important input to the Gothenburg Protocol Review currently underway in the year 2021

Comparison of model concepts for nutrient availability and soil acidity in terrestrial ecosystems

STOWA heeft het initiatief genomen om samen met een aantal partijen een klimaatrobuuste Waterwijzer Natuur (WWN) te ontwikkelen. Een instrument dat de effecten van klimaatverandering en het waterbeheer op de terrestrische vegetatie van natuurgebieden dient te kunnen berekenen. Klimaatverandering zal vooral gevolgen voor natuurlijke vegetaties hebben via veranderingen in de waterbalans. Die veranderingen werken namelijk door op de bodemtemperatuur en de hoeveelheid vocht, zuurstof en nutriënten die voor de planten in het wortelmilieu beschikbaar zijn. Klimaatverandering noopt dan ook tot het stellen van enkele essentiële vragen, zoals: Welke maatregelen zijn er nodig om natuurdoelen in de toekomst zeker te stellen? Welke alternatieve doelen kunnen we overwegen als in het verleden vastgestelde natuurdoelen niet meer haalbaar blijken te zijn onder een veranderend klimaat? Waar liggen straks, in het klimaat van de toekomst, de beste kansen voor het creëren van hotspots van biodiversiteit? Dit rapport geeft een overzicht van de overeenkomsten en verschillen van de wijze waarop PROBE (KWR) en VSD+ (WEnR) de nutriëntenbeschikbaarheid en zuurgraad in (half)natuurlijke terrestrische ecosystemen voorspellen in afhankelijkheid van milieu, (vnl. atmosferische depositie), klimaat (vnl. temperatuur en neerslag) en waterbeheerscenario’s

27th Annual Report 2018 : Convention on Long-range Transboundary Air Pollution. International Cooperative Programme on Integrated Monitoring of Air Pollution Effects on Ecosystems

The Integrated Monitoring Programme (ICP IM) is part of the effect-oriented activities under the 1979 Convention on Long-range Transboundary Air Pollution, which covers the region of the United Nations Economic Commission for Europe (UNECE). The main aim of ICP IM is to provide a framework to observe and understand the complex changes occurring in natural/semi natural ecosystems. This report summarizes the work carried out by the ICP IM Programme Centre and several collaborating institutes. The emphasis of the report is in the work done during the programme year 2017/2018 including: - A short summary of previous data assessments - A status report of the ICP IM activities, content of the IM data base, and geographical coverage of the monitoring network - A report on long-term changes in the inorganic nitrogen output fluxes in European ICP Integrated Monitoring catchments and an assessment of the role of internal nitrogen parameters - A progress report on dynamic soil-vegetation modelling - A literature review: Post disturbance vegetation succession and resilience in forest ecosystems - National Reports on ICP IM activities are presented as annexes