Concept Of Potential Natural Vegetation Research Articles

Current and potential carbon stock in the forest communities of the Białowieża Biosphere Reserve

Specifying the upper bound of C storage in forest ecosystems allows an estimate of the amount of C that can be stored in the future. The Białowieża Forest in NE Poland is the last relic forest in the European lowlands. Still, it has been subject to various natural and human-induced disturbances and its C stock has been reduced. The main goal of our study was therefore to assess the current and potential C stock in the forest communities of the Białowieża Biosphere Reserve (597 km2), taking into account the diversity of habitats as well as different protection and management practices. For this we identified 13 forest communities and quantified their current C stock stored in all major pools (living trees, deadwood and soil). We used vegetation and soil data collected in 2018 at 1391 systematically distributed 0.04 ha forest plots (sampling grid 650 × 650 m). We used the concept of potential natural vegetation (PNV) and randomized upscaling of plot level current biomass C stock values to estimate the upper bounds of biomass C stocks possible to obtain at the stand level. We showed that the Białowieża Forest stores currently 300 Mg C ha−1 (17.2 Tg C), of which 41% is accumulated in biomass, with significant variation among different forest communities and management regimes. We obtained the upper bounds of biomass C stocks ranging from 94 Mg ha−1 for swamp pine forest to 223 Mg ha−1 for lime-oak-hornbeam forest. We estimated the gap between the current and potential C stock in biomass at 66 Mg ha−1 (3.8 Tg); 62% of the potential level is achieved in managed forests, and 76% in the National Park. Our findings may be used in planning forest management aimed toward long-term C storage, and the obtained upper bounds can serve as benchmarks in assessing C storage potential of similar forest types elsewhere. We also suggest that the potential of ecosystems to store C should be considered in the landscape context, i.e. by taking into account the spatial extent of PNV habitats and their unequal capacity to provide C storage service.

The relevance of the concept of potential natural vegetation in the Anthropocene

ABSTRACT Background The concept of potential natural vegetation (PNV) refers to self-sustaining mature vegetation matching the environmental conditions a site offers. Despite its widespread use, the applicability of the concept under the current level of human impacts on the environment has been criticised. Aims We re-examine the original publication of the PNV concept and its development over time to identify the sources of tension between theory and application and to direct the discourse onto a common ground of understanding. Our focus is on the relationship between human impacts and PNV. Arguments Based on extended excerpts and detailed interpretation, we affirm that PNV applies to a specific point in time. Consequently, PNV is independent of any realised vegetation including past undisturbed (pre-human) vegetation. We track possible routes and reasons for alternative interpretations. We identify PNV as a mental concept, or a neutral model, that represents baseline vegetation potential that excludes contemporary human management but includes past environment-modifying impacts. We address how a concept reflecting unmanaged vegetation can be important for application in a world transformed by humans. Conclusions Rather than abandoning the concept, we advocate adhering to using it in the original sense of its definition. This way PNV can serve research as a neutral model and support sustainable land use planning.

The potential natural vegetation of large river floodplains – From dynamic to static equilibrium

The potential natural vegetation (PNV) is a useful benchmark for the restoration of large river floodplains because very few natural reference reaches exist. Expert-based approaches and different types of ecological models (static and dynamic) are commonly used for its estimation despite the conceptual differences they imply. For natural floodplains a static concept of PNV is not reasonable, as natural disturbances cause a constant resetting of succession. However, various forms of river regulation have disrupted the natural dynamics of most large European rivers for centuries. Therefore, we asked whether the consideration of succession dynamics and time dependent habitat turnover are still relevant factors for the reconstruction of the PNV.To answer this we compared the results of a simulation of the vegetation succession (1872–2016) of a segment of the upper Rhine river after regulation (damming, straightening and bank protection) to different statistic and expert-based modelling approaches for PNV reconstruction. The validation of the different PNV estimation methods against a set of independent reference plots and the direct comparison of their results revealed very similar performances. We therefore conclude that due to a lack of large disturbances, the vegetation of regulated large rivers has reached a near-equilibrium state with the altered hydrologic regime and that a static perception of its PNV may be justified. Consequently, statistical models seem to be the best option for its reconstruction since they need relatively few resources (data, time, expert knowledge) and are reproducible.

Biogeodiversity and pedodiversity islands in arid lands of Europe (Almería Province, Spain)

Plant and soil landscapes across bioclimatic belts and drainage basins were studied using georeferenced databases in arid lands of SE Spain, the driest area of Europe. The syntaxonomic system was used to analyze phytocenoses and bioclimatic belts, as well as the concept of potential natural vegetation (PNV), a common approach in many countries of continental Europe. Soil types included in pedological databases were classified using the World Reference Base for Soil Resources international system (FAO 1998). Both bioclimatic belts and drainage basins effectively discriminate soil and plant assemblages in the study area of the Almeria province. The syntaxonomic perspective permits distinguishing between PNV dependent on (i) climate (climatophylous), (ii) climate and lithology, and (iii) soils (edaphophylous). Richness-area relationships of plant and soil assemblages fit well to power law distributions, showing few idiosyncratic differences. PNV, lithological associations, and soil richness are clearly correlated with the area of each climatic beltand watershed. PNV and pedotaxa richness (understood as a number of taxa at a given hierarchical level) increases from the mountain tops to the coastal lands. Around 59% of the PNV units are edaphophylous and 87% of these are edaphohygrophylous that require water supply or tolerate water excess in riverbed ramblas (dry watercourses). Edaphohygrophylous PNV are distributed in small patches within a very arid matrix. They can be considered as plant “biodiversity islands”, a concept different from that of “fertility islands” used by ecologists in arid land studies. The spatial dispersion of these phytocenoses prevents adequate preservation in the frame of conservation biology policies. At landscape level, the extent of plant communities is as follows: PNV climate dependent > PNV climate-lithology dependent > PNV soil dependent. The diversity of plant communities follows an opposite trend: PNV soil dependent > PNV climate-lithology dependent > PNV climate dependent. The PNV most conditioned by soil properties are located along the streambeds of ramblas. These fluvial sediments are not reported as soil materials in soil maps. PNV, soils and lithological associations by drainage basins conform to the predictions of the statistical tool termed nested subsets theory. However, lithological associations by climatic belts depart from this spatial pattern.

Potential natural vegetation and pre‐anthropic pollen records on the Azores Islands in a Macaronesian context

AbstractThis paper discusses the concept of potential natural vegetation (PNV) in the light of the pollen records available to date for the Macaronesian biogeographical region, with emphasis on the Azores Islands. The classical debate on the convenience or not of the PNV concept has been recently revived in the Canary Islands, where pollen records of pre‐anthropic vegetation seemed to strongly disagree with the existing PNV reconstructions. Contrastingly, more recent PNV model outputs from the Azores Islands show outstanding parallelisms with pre‐anthropic pollen records, at least in qualitative terms. We suggest the development of more detailed quantitative studies to compare these methodologies as an opportunity for improving the performance of both. PNV modelling may benefit by incorporating empirical data on past vegetation useful for calibration and validation purposes, whereas palynology may improve past reconstructions by minimizing interpretative biases linked to differential pollen production, dispersal and preservation.

Implementation and application of multiple potential natural vegetation models – a case study of Hungary

AbstractQuestionsMultiple potential natural vegetation (MPNV) is a framework for the probabilistic and multilayer representation of potential vegetation in an area. How can an MPNV model be implemented and synthesized for the full range of vegetation types across a large spatial domain such as a country? What additional ecological and practical information can be gained compared to traditional potential natural vegetation (PNV) estimates?LocationHungary.MethodsMPNV was estimated by modelling the occurrence probabilities of individual vegetation types using gradient boosting models (GBM). Vegetation data from the Hungarian Actual Habitat Database (MÉTA) and information on the abiotic background (climatic data, soil characteristics, hydrology) were used as inputs to the models. To facilitate MPNV interpretation a new technique for model synthesis (re‐scaling) enabling comprehensive visual presentation (synthetic maps) was developed which allows for a comparative view of the potential distribution of individual vegetation types.ResultsThe main result of MPNV modelling is a series of raw and re‐scaled probability maps of individual vegetation types for Hungary. Raw probabilities best suit within‐type analyses, while re‐scaled estimations can also be compared across vegetation types. The latter create a synthetic overview of a location's PNV as a ranked list of vegetation types, and make the comparison of actual and potential landscape composition possible. For example, a representation of forest vs grasslands in MPNV revealed a high level of overlap of the potential range of the two formations in Hungary.ConclusionThe MPNV approach allows viewing the potential vegetation composition of locations in far more detail than the PNV approach. Re‐scaling the probabilities estimated by the models allows easy access to the results by making potential presence of vegetation types with different data structure comparable for queries and synthetic maps. The wide range of applications identified for MPNV (conservation and restoration prioritization, landscape evaluation) suggests that the PNV concept with the extension towards vegetation distributions is useful both for research and application.

Regionalization of land use impact models for life cycle assessment: Recommendations for their use on the global scale and their applicability to Brazil

Life Cycle Assessment (LCA) is the main technique for evaluate the environmental impacts of product life cycles. A major challenge in the field of LCA is spatial and temporal differentiation in Life Cycle Impact Assessment (LCIA) methods, especially impacts resulting from land occupation and land transformation. Land use characterization modeling has advanced considerably over the last two decades and many approaches have recently included crucial aspects such as geographic differentiation. Nevertheless, characterization models have so far not been systematically reviewed and evaluated to determine their applicability to South America. Given that Brazil is the largest country in South America, this paper analyzes the main international characterization models currently available in the literature, with a view to recommending regionalized models applicable on a global scale for land use life cycle impact assessments, and discusses their feasibility for regionalized assessment in Brazil. The analytical methodology involves classification based on the following criteria: midpoint/endpoint approach, scope of application, area of data collection, biogeographical differentiation, definition of recovery time and reference situation; followed by an evaluation of thirteen scientific robustness and environmental relevance subcriteria. The results of the scope of application are distributed among 25% of the models developed for the European context, and 50% have a global scope. There is no consensus in the literature about the definition of parameters such biogeographical differentiation and reference situation, and our review indicates that 35% of the models use ecoregion division while 40% use the concept of potential natural vegetation. Four characterization models show high scores in terms of scientific robustness and environmental relevance. These models are recommended for application in land use life cycle impact assessments, and also to serve as references for the development or adaptation of regional methodological procedures for Brazil.

Long‐term vegetation stability and the concept of potential natural vegetation in the Neotropics

AbstractWhen vegetation trends over time are analysed from an appropriate long‐term perspective using palaeoecological records, the concept of potential natural vegetation (PNV) is unsupported because of continual vegetation changes driven by natural or anthropic forcings. However, some palaeoecological records show long‐lasting (i.e. millennial) vegetation stability at multidecadal to centennial time scales in the absence of natural and human drivers of change, which fits within the definition of PNV. A more detailed palaeoecological analysis of these records shows that they are an exception rather than a rule, and that they cannot be differentiated from other transient ecological states. Therefore, long records of vegetation stability cannot be considered to be valid evidence for PNV. From a palaeoecological perspective, the PNV concept is concluded to be unnecessary, even in cases of multidecadal to centennial vegetation stability in the absence of environmental disturbance.

Towards a more transparent use of the potential natural vegetation concept – an answer to Chiarucci et al.

AbstractIn this paper, the concerns of Chiarucci et al. () regarding use of the potential natural vegetation (PNV) concept are addressed, as voiced in the forum section of theJournal of Vegetation Science. First, we rectify some unfounded expectations concerningPNV, including a relationship with prehuman vegetation and phytosociology. Second, we point out issues that pose considerable challenges inPNVand require common agreement. Here, we address the issue of time and disturbance. We propose to use the staticPNVconcept as a baseline, a null model for landscape assessment and in comparisons. Instead of changing thePNVconcept itself, we introduce a new term, potential future natural vegetation (PFV) to cover estimations of potential successional outcomes. Finally, we offer a new view ofPNVwith which we intend to make the use ofPNVestimates more transparent. We formalize thePNVtheory into a partial cause‐effect model of vegetation that clearly states which effects on vegetation are factored out during its estimation. Further, we also propose to assessPNVin a probabilistic setting, rather than providing a single estimate for one location. This multiplePNVwould reflect our uncertainty about the vegetation entity that could persist at the locality concerned. Such uncertainty arises from the overlap of environmental preferences of different mature vegetation types. Thus reformulated, we argue that thePNVconcept has much to offer as a null model, especially in landscape ecology and in site comparisons in space and time.

The concept of potential natural vegetation: an epitaph?

We discuss the usefulness of the concept of Potential Natural Vegetation (PNV), which describes the expected state of mature vegetation in the absence of human intervention. We argue that it is impossible to model PNV because of (i) the methodological problems associated to its definition and (ii) the issues related to the ecosystems dynamics.We conclude that the approach to characterizing PNV is unrealistic and provides scenarios with limited predictive power. In places with a long-term human history, interpretations of PNV need to be very cautious, and explicit acknowledgement made of the limitations inherent in available data.

Understanding properly the `potential natural vegetation' concept

AbstractThis is a response to critical comments concerning the inappropriate use of the potential natural vegetation (PNV) concept made in a recent contribution to the Commentary section of this journal. We consider that the PNV concept has been misinterpreted. PNV has been used extensively in several European countries since the mid‐1950s and was never intended to be used to make a prediction of what vegetation would dominate in an area if human influence were removed. PNV maps express hypothetical assumptions of what corresponds to dominant or natural vegetation in each area. Remnants of the vegetation of the past provided by palaeopalynology and other disciplines provide valuable information for interpreting modern vegetation, but natural changes and anthropogenic influences operating over the last millennia have to be taken into account. Annex I of the Habitats Directive provides a balanced list of habitat types for implementing conservation policies within the European Union.

Floristic-phytosociological approach, potential natural vegetation, and survival of prejudice

Carrion & Fernandez (2009; further C&F) in a recent commentary on a paper published in Journal of Biogeography criticised an obvious mismatch between the predictions about the patterns of potential natural vegetation (PNV) made by phytosociologists, and those underpinned by pollen data. C&F used this stage to take a broad sway on phytosociology in general (stopping only very short of denying it status of science), blaming power of tradition and influence of personal cult for ignoring scientific evidence. In my response I show that C&F have misinterpreted the concept of PNV, rendering their comparisons irrelevant. C&F obviously overslept the progress descriptive vegetation science made in recent decades, relegating their heavy criticism of phytosociology into the realm of prejudice.

都市内復元型ビオトープにおける蘚苔類フロラの変化

To promote the understanding of succession process in artificial urban ecological environments, we invested the changes in bryophyte flora in an urban afforested woodland in Kyoto city. Focusing on three bryophyte functional groups (substrate preference, growth form and reproductive type), we compared the bryophyte flora in 2002 with those in 2007. A total of 41 species were recorded in 2002, and 52 species in 2007. The number of bryophyte species on trunk increased markedly compared to those of bryophyte speceis on other substrates, while bryophytes on rock showed higher turn over rate.From a view point of growth forms, bryophytes of cushion form, thread-like form, small-size appressed form and thalloid form increased greater than bryophytes of other growth forms, and bryophytes of small turf form and squamous form had a higher turn over rate. Additionally, the number of bryophyte species with asexual reproduction invaded more frequently than those of bryophyte species without asexual reproduction. These differences were explained by characteristic of bryophyte functional groups. In conclusion, to restore bryophyte vegetation in this study site based on the concept of potential natural vegetation, planting trees around the site, placing large rocks in the site and maintenance such as weeding were considered to be effective for the restoration of native bryophyte vegetation. Moreover, it was possible that introducing bryophyte species with poor dispersal ability into this site was needed for the restoration.

FOREWORD TO THE PROCEEDINGS OF THE CONFERENCE 'EUROPEAN VEGETATION IN THE 21ST CENTURY'

FOREWORD TO THE PROCEEDINGS OF THE CONFERENCE 'EUROPEAN VEGETATION IN THE 21ST CENTURY' The conference 'European vegetation in the 21st century' was held in theNational University of Ireland, Galway, in June 2005 and was succeeded by a week-long excursion to some of themost important sites for Irishvegetation. The three-day conference was attended by over 130 delegates from 21 countries from as far afield asRussia and Georgia in the east, Sweden in the north,Malta in the south and Ireland in thewest. Itwas the fourthmajor meeting of European vegetation scientists in Irelandwithin the last 100 years. The firstof these, the International Phyto geographical Excursion, was held in 1911 and was organised by the illustrious Irish botanist Robert Lloyd Praeger. Among the participants was the eminent British botanist Arthur Tansley, who subsequently described aspects of Irish vegetation in his seminal book The British Islands and their vegetation(Tansley 1939). The second International Phytogeographical Excursion, held in 1949, was organised by the late Professor David Webb. The star attractions on that occasion were none other thanBraun-Blanquet and T?xen themselves,who compiled thefirstaccounts of Irishvegetation using the continental phytosociological methodology. Their account, published in Irische Pflanze ngesellschaften(Braun-Blanquet and T?xen 1952) has since become a standard reference for all aspiring Irish vegetation scientists. The third meeting, held by the International Society for Vegetation Science, took place in 1980 and was organised byDr Austin O'Sullivan, Dr Jim White and the late Professor Webb. The Galway conference provided an oppor tunity to take stock of developments in Irish vegetation studies over the last 25 years. In addition, with our closer integration into the European Community and its recent expansion eastward, itwas also an opportunity to take a broader look at developments invegetation science. It also coincided with the centenary of the publication of the firstdetailed vegetation map of Irishvegetation, thatof the 'districtlying south of Dublin' by Pethybridge and Praeger (1905). In contrast to other countries, studies of Irish vegetation have, until relativelyrecently,been fitful. After the map produced by Pethybridge and Praeger in 1905 little furtherwas done by Irish scientists until the 1960s and 1970s, when Professor J.J. Moore and Dr Austin O'Sullivan enthusiastically embraced the continental approach to phyto sociology. Detailed studies of grasslands and peatlands were undertaken and preliminarymaps were produced (seeWhite 1982). Initial studies of Irish woodlands were begun (e.g. Kelly 1975). Following the enactment of the 1976Wildlife Act the pace of surveying and classifying vegetation intensifiedwith systematic coverage of numerous habitat types, such as raised bogs (e.g.Douglas and Grogan 1985; Cross 1990),machair (Crawford etal. 1996), saltmarshes (Curtis and Sheehy Skeffington 1998). The informationgathered fromthese surveys provided a basis for the first steps towards the conservation of Irish flora and habitats under the Wildlife Act. Much of this information was also incorporated into the recently published Map of the Natural Vegetation of Europe (Bohn et al. 2003; 2004), one of the principal stimuli for the conference. This map is the result ofmore than 25 years of international cooperation between vegetation scientists from nearly all countries of Europe, and it is the firstof itskind for an entire continent. The map alone, with nearly 700 units, is a work of art, and while some botanists have reservations regarding the concept of potential natural vegetation, it has already been widely accepted as a useful tool in termsof planning and management. The second stimulus for the conference, the EU Habitats Directive, has become the principal tool for nature conservation, not only within Ireland but also throughout theEU and applicant states.All 25 member statesare obliged to identify, protect, monitor and manage a network of areas or Sites of Community Importance (SCIs), known as Natura 2000 sites, and vegetation scientists have played an important role in defining and implementing this directive. Europe has a long history of landuse andmanagement, with the result that very little undisturbed natural vegetation remains. There are, however, extensive areas of managed natural and semi-natural vegetation and 'cultural landscapes' of high conservation value. In recent decades increased urbanisation and the intensificationof agriculture and forestryhave led Biology and Environment: Proceedings of the Royal Irish Academy, Vol. 106B, No. 3, 163-165...

Are potential natural vegetation maps a meaningful alternative to neutral landscape models?

Abstract. In this paper, we present a short overview of neutral landscape models traditionally adopted in the landscape ecological literature to differentiate landscape patterns that are the result of simple random processes from patterns that are generated from more complex ecological processes. Then, we present another family of models based on Tuxen’ s definition of potential natural vegetation that play an important role, especially in Europe, for landscape planning and management. While neutral landscape models by their very nature do not take into account vegetation dynamics, nor abiotic constraints to vegetation distribution, the concept of potential natural vegetation includes the effects of vegetation dynamics in a spatially explicit manner. Therefore, we believe that distribution maps of potential natural vegetation may represent an ecological meaningful alternative to neutral landscape models for evaluating the effects of landscape structure on ecological processes.

Карты потенциальной естественной растительности как альтернатива компьютерным нейтральным ландшафтным моделям

This paper provides a short critical overview of computer generated neutral landscape models traditionally adopted in landscape ecology literature. Then, another family of models based on Tüxen's concept of potential natural vegetation is presented. The suggestion is put forward that potential natural vegetation maps have a number of properties which may render them desirable as an ecological meaningful baseline for the evaluation of the effects of landscape structure on ecological processes.

A vegetation map of The Netherlands, based on the relationship between ecotopes and types of potential natural vegetation

The method of mapping the vegetation on scale 1: 200,000 and the starting points in relation to the potential natural vegetation and ecotopes, are discussed. In view of the planological background of this study, some restrictions have been added to the concept of potential natural vegetation, concerning the period of development and the human influence. The relationship between soil, ground water and vegetation was studied, which resulted in the map of the potential natural vegetation. Each type of potential natural vegetation stands for a series of vegetation types on the same site. Seven main series, with a number of sub-series are distinguished. Within each vegetation series the plant communities have been spread over five groups, according to their structure and naturalness. Ecotopes and ecotope complexes are considered as landscape ecological units. A list of ecotopes was obtained by interpreting topographical maps and by inventory data. The actual vegetation was mapped by estimating the size of the ecotopes within the separate areas. It was expressed in a five figure code for the five groups from the vegetation and ecotopes is combined into the vegetation map of The Netherlands. Interpretation problems, some of them specific for The Netherlands, are discussed and some remarks are made on the necessity of further research.