Showing papers in "Plant Biosystems in 2010"

Non‐native flora of Italy: Species distribution and threats

Abstract: In this paper, we provide an overview of the distribution and invasive status of non‐native species in the Italian flora across its administrative regions, biogeographic regions and main land use types, and a synthesis of current knowledge on the threats they pose within the country. The information on non‐native plant species collected during the project “A survey of the non‐native Italian flora” was used to compile comprehensive regional and national databases. The number of non‐native species within a given administrative region increases in proportion to its size, resident population density and latitude, reaching the highest values in the intensively cultivated, heavily industrialized and urbanized Po Plain in northern Italy. The number of casual species is positively correlated with the number of yearly visitors in each region and negatively correlated with the proportion of mountainous terrain within the region. If compared with the Continental and Mediterranean biogeographic regions, the ...

A plant root system architectural taxonomy: A framework for root nomenclature

Abstract: Research into root system morphology over the last two centuries has developed a diverse set of terminologies that are difficult to apply consistently across species and research specialties. In response to a need for better communication, a workshop held by the International Society for Root Research established some nomenclature standards for root research. These standards and their justification are presented in this study. A framework for a root system architectural taxonomy is created by defining four main classes of root: the tap root, that is, the first root to emerge from the seed; lateral roots, which are branches of other roots; shoot‐borne roots, which arise from shoot tissues; and basal roots, which develop from the hypocotyl, that is, the organ which is between the base of the shoot and the base of the tap root. It is concluded that adherence to the presented taxonomy will reduce confusion and eliminate some of the current confounding of results.

Multi‐taxon and forest structure sampling for identification of indicators and monitoring of old‐growth forest

Abstract: The most commonly used old‐growth forest indicators are structural attributes; nevertheless, they do not necessarily represent the biodiversity value of old‐growth forests. The aim of this study is to analyse the relationships between species richness data of different taxa and structural indicators of old‐growth and to identify taxonomic/functional groups, species and structural attributes that may be used as indicators of old‐growth. To achieve this goal we sampled forest structure, vascular plants, lichens, bryophytes, fungi, saproxylic beetles and birds in mature and old‐growth stands in southern Italy. We calculated Spearman’s correlation coefficients between species richness data and structural attributes. Analyses of indicator species, co‐occurrences and two‐way clusters were performed on the multi‐taxonomic list. The group of vascular plants most significantly correlated with other groups in terms of species richness; furthermore, it displays the highest proportion of between‐group co‐occ...

Reconstructing past cultural landscape and human impact using pollen and plant macroremains

Abstract: Three examples of plant landscape shaping, carried out by Iron Age populations living in different geographical areas, are presented. The examples differ in population type (Garamantes, Etruscans, and Romans), archaeological context (settlement, necropolis, furnace, port), and area of plant exploitation (respectively, Fezzan – Libyan Sahara and Tuscany, Latium – central Italy). The leitmotiv of the three parallel investigations highlighted that humans induced clear changes in plant cover modifying the quantitative ratio among native elements and spreading the plants of economic interest even outside of their natural habitats. Micro- and macroremain analyses once more enhanced that landscape reconstruction depends on both wild and cultivated plants, and that the cultural plant landscape is composed of a complex mixture of indigenous and exotic elements. Archaeobotany results in great help in reviewing ancient prejudices, rewriting history in a modern ecological view, also discovering a different r...

Experimental and modelling studies of drought-adaptive root architectural traits in wheat (Triticum aestivum L.)

Abstract: This paper presents an interdisciplinary approach to crop improvement that links physiology with plant breeding and simulation modelling to enhance the selection of high‐yielding, drought‐tolerant varieties. In a series of field experiments in Queensland, Australia, we found that the yield of CIMMYT wheat line SeriM82 ranged from 6% to 28% greater than the current cultivar Hartog. Physiological studies on the adaptive traits revealed that SeriM82 had a narrower root architecture and extracted more soil moisture, particularly deep in the profile. Results of a simulation analysis of these adaptive root traits with the cropping system model APSIM for a range of rain‐fed environments in southern Queensland indicated a mean relative yield benefit of 14.5% in water‐deficit seasons. Furthermore, each additional millimetre of water extracted during grain filling generated an extra 55 kg ha−1 of grain yield. Further root studies of a large number of wheat genotypes revealed that wheat root architecture is...

Archaeobotany for cultural landscape and human impact reconstructions

Abstract: The special issue “Cultural landscapes of the past” is the outcome of the idea to present a set of researches centered on past cultural landscapes reconstructed principally on the basis of an integ...

Lichens and bryophytes as indicators of old‐growth features in Mediterranean forests

Abstract: This study is focused on the selection of variables affecting lichen and bryophyte diversity in Mediterranean deciduous forests. Plots representing two forest types (Fagus sylvatica and Quercus cerris forests) and two forest continuity categories (old‐growth (OG) and non‐OG forests) were selected in the Cilento and Vallo di Diano National Park (Italy). The presence and the abundance of bryophytes and epiphytic lichens were recorded. Structural variables of the forests and vascular plant species richness have been used as predictors. A strong positive correspondence between the two groups of organisms was found. Higher species richness and the distribution of rare species are related to OG stands, while a qualitative (species composition) rather than a quantitative (species richness) difference between the two forest types was observed. Some species elsewhere considered as indicators of forest continuity, such as Lobaria pulmonaria, Antitrichia curtipendula, and Homalothecium sericeum, are associa...

Prehistoric impact on landscape and vegetation at high altitudes: An integrated palaeoecological and archaeological approach in the eastern Pyrenees (Perafita valley, Andorra)

Abstract: A multi-proxy palaeoenvironmental study (pollen, non-pollen palynomorphs-NPP, macrocharcoal particles) of a small fen located in the Perafita valley (2240 m a.s.l, eastern Pyrenees, Andorra) was undertaken to trace prehistoric human activities related to woodland clearance and past land-uses at high altitudes. The results of this study constrained by 9 AMS radiocarbon measurements are combined with archaeological data and compared with similar research carried out at the same altitude in the adjacent Madriu valley (Andorra). The overall objectives of this article are, first, to formulate different chronological patterns and spatial land-use distribution at a micro-regional scale during prehistory and, second, to discuss different drivers of prehistoric occupation models in the eastern Pyrenean highlands. The palaeoecological study of the Planells de Perafita fen was performed at high temporal resolution, allowing us to focus on detailed prehistoric (mainly Mesolithic and Neolithic) and Bronze Age...

Role of macrophyte communities as bioindicators of water quality: Application on the Tiber River basin (Italy)

Abstract: The aquatic plant communities of the Tiber River basin have been examined to evaluate their role as bioindicators of the water quality of the Italian peninsular rivers. The compatibility curves of phytocoenoses to water chemico‐physical gradients show a correlation between the distribution pattern of the vegetation types and the water’s chemico‐physical features, such as different levels of water pollution. In particular, Fontinaletum antipyreticae, Ranunculo‐Sietum, Elodeo‐Potametum crispi and Nasturtietum officinalis develop in meso‐eutrophic and fairly clean water, Potamogeton nodosus community and Ceratophylletum demersi in eutrophic water of medium quality, while Myriophylletum spicati and especially Potametum pectinati and algal communities with Entheromorpha flexuosa are found in hypertrophic water of poor quality. These phytocoenoses can be utilised as valid bioindicators of water quality. On the contrary, Callitrichetum stagnalis, Myriophylletum verticillati, Najadetum marinae and algal ...

Pollen from archaeological layers and cultural landscape reconstruction: Case studies from the Bradano valley (Basilicata, southern Italy)

Abstract: The article aims at presenting some aspects of environmental reconstruction through pollen analysis from archaeological contexts. The anthropogenic pollen transport into archaeological sites is regarded as an interesting tool to improve knowledge on flora and vegetation in the area of influence of sites. The zoophilous plants can be found more easily than in the regional airborne pollen rain where anemophilous pollen is generally overrepresented. Moreover, pollen from archaeological contexts is mainly a result of the cultural landscape shaped by human activities. Two case studies from the Bradano Valley (Basilicata, southern Italy), rich in archaeological sites dating altogether from the Middle Bronze Age to the Medieval age, are reported. Difesa San Biagio and its surroundings is one of the biggest settlements of the area, settled in early times by Enotrians. Altojanni is an extended area mainly frequented in Hellenistic, Roman late Imperial and Medieval times. A very open landscape, and clear s...

Structural characteristics and aboveground biomass of old‐growth spruce–fir stands in the eastern Carpathian mountains, Ukraine

Abstract: Temperate old‐growth forests are known to have ecological characteristics distinct from younger forests, but these have been poorly described for the remaining old‐growth Picea abies–Abies alba forests in the eastern Carpathian mountains. In addition, recent studies suggest that old‐growth forests may be more significant carbon sinks than previously recognized. This has stimulated interest in quantifying aboveground carbon stocks in primary forest systems. We investigated the structural attributes and aboveground biomass in two remnant old‐growth spruce–fir stands and compared these against a primary (never logged) mature reference stand. Our sites were located in the Gorgany Nature Reserve in western Ukraine. Overstory data were collected using variable radius plots; coarse woody debris was sampled along line intercept transects. Differences among sites were assessed using non‐parametric statistical analyses. Goodness‐of‐fit tests were used to evaluate the form of diameter distributions. The res...

Ecological portrayal of old‐growth forests and persistent woodlands in the Cilento and Vallo di Diano National Park (southern Italy)

Abstract: The maintenance of certain levels of old forest represents a cornerstone of the EU’s biodiversity management strategy. A consensus on a single general ecological definition of old‐growth is particularly difficult in Mediterranean Europe. The present paper deals with old‐growth forests and persistent woodlands in the Cilento and Vallo di Diano National Park (PNCVD) to give an ecological understanding of forest complexity and dynamics under a multiscale and multidisciplinary perspective. The multiscale approach ranged from the identification and mapping of potential old‐growth stands at landscape scale to a two‐level field review of forest stand features. Field sampling involved a multidisciplinary team of researchers in forest structure, pedologic environment, soil microbial activity, flora and vegetation and deadwood components. The research provided sound knowledge about old‐growthness features in the PNCVD that constitutes a unique case study in the whole Mediterranean basin. The integration of...

The effect of grazing pressure on species richness, composition and productivity in North Adriatic Karst pastures

Abstract: We studied the effects of sheep grazing intensity and abandonment on plant species richness and composition, plant life forms and the productivity of North Adriatic Karst pastures The experimental sites were under controlled grazing regimes (heavy, moderate, light and abandonment) for 10 years Data were collected during one season; plant species composition, the number of species and above‐ground and below‐ground biomass were evaluated Species richness was significantly reduced with increasing grazing intensity and abandonment The greatest differences in species composition were recorded for the heavily grazed site owing to the appearance of a group of grasslands species typical of nutrient‐rich soil Heavy grazing increased therophytes and decreased the proportion of chamaephytes and geophytes Above‐ground productivity at the season's peak was typical of subhumid grasslands (up to 500 g m−2) and was significantly the highest in the abandoned pasture Below‐ground biomass was significantly t

Stand dynamics of Dinaric old‐growth forest in Slovenia: Are indirect human influences relevant?

Abstract: Understanding forest stand structural change is crucial for forest ecosystem research and management. The aim of our research was to identify structural and compositional changes and possible natural and anthropogenic causes of these changes in an old‐growth silver fir‐beech forest in the Dinaric mountains of Slovenia. Data on stand structure of the Rajhenavski Rog (51.14 ha) forest reserve originated from traditional methods, including five successive full callipering (1957–2007), two regeneration inventories and analysis of developmental phases (1984, 2007). A drastic decrease in the silver fir proportion in the last 50 years was probably caused by two indirect anthropogenic factors: polluted air and heavy browsing damage of silver fir regeneration. Nevertheless, other factors including reciprocal replacement of fir and beech and climate change also influenced the species composition, as similar processes were documented in the past with less air pollution. Furthermore, the alternation of fir a...

Linking taxonomical and functional biodiversity of saproxylic fungi and beetles in broad‐leaved forests in southern Italy with varying management histories

Abstract: The fundamental ecological significance of deadwood decomposition in forests has been highlighted in several reviews, some conclusions regarding silviculture being drawn. Old‐growth forests are natural centres of biodiversity. Saproxylic fungi and beetles, which are vital components of these ecosystems, occupy a variety of spatial and trophic niches. Fungal and beetle diversity on coarse woody debris (CWD) was analysed in 36 forest sites in the Cilento and Vallo di Diano National Park, Italy. The data were analysed by DCA and Spearman’s rank correlation. The results provide empirical evidence of the existence of a pattern of joint colonization of the woody substrate by fungi and beetles, which includes an assemblage of reciprocal trophic roles within fungal/beetle communities. These organisms act together to form a dynamic taxonomical and functional ecosystem component within the complex set of processes involved in wood decay. The variables most predictive of correlations between management‐rela...

Old‐growth forests, carbon and climate change: Functions and management for tall open‐forests in two hotspots of temperate Australia

Abstract: The prognosis and utility under climate change are presented for two old‐growth, temperate forests in Australia, from ecological and carbon accounting perspectives. The tall open‐forests (TOFs) of south‐western Australia (SWA) are within Australia’s global biodiversity hotspot. The forest management and timber usage from the carbon‐dense old‐growth TOFs of Tasmania (TAS) have a high carbon efflux, rendering it a carbon hotspot. Under climate change the warmer, dryer climate in both areas will decrease carbon stocks directly; and indirectly through changes towards dryer forest types and through positive feedback. Near 2100, climate change will decrease soil organic carbon (SOC) significantly, e.g. by ∼30% for SWA and at least 2% for TAS. The emissions from the next 20 years of logging old‐growth TOF in TAS, and conversion to harvesting cycles, will conservatively reach 66(±33) Mt‐CO2‐equivalents in the long‐term – bolstering greenhouse gas emissions. Similar emissions will arise from rainforest SO...

Monitoring and assessing old‐growth forest stands by plot sampling

Abstract: Forest inventories are evolving towards multipurpose resource surveys, broadening their scope by including additional topics such as biodiversity issues. Surprisingly, few quantitative surveys have been devoted to old‐growth forests, even if they constitute the most acknowledged forest biodiversity icons. In this framework, the use of probabilistic sampling may provide an effective as well as rigorous support for monitoring and assessing old‐growth forests. To this purpose, the present paper proposes a two‐phase sampling scheme. In the first phase, a coarse survey of few floristic and stand structural attributes is carried out by means of small plots systematically placed on the study area. Subsequently, in the second phase, a fine assessment of a large number of ecological attributes is performed on a subset of enlarged plots selected among the first‐phase ones by means of simple random sampling without replacement. The proposed sampling scheme is implemented for monitoring and assessing the old...

Bacterial and fungal communities associated with Tuber magnatum-productive niches.

Abstract: Truffles are hypogeous ectomycorrhizal fungi of ecological interest for forestry in soils of the northern hemisphere, and of economical relevance for food markets worldwide. The molecular mechanisms that control truffle body formation are largely unknown, as well as the environmental factors that are likely involved. Among the latter, it has been hypothesized that soil‐borne communities may have an impact on truffle production. To address this question, we investigated bacterial and fungal communities resident in productive versus adjacent non‐productive grounds of the white truffle Tuber magnatum by using PCR‐DGGE. Although bacterial communities were generally highly similar across all samples within the grounds, profiles did cluster according to the productivity of circumscribed niches, and a Moraxella osloensis population appeared to be associated with productive sites. Fungal communities revealed several populations, yet showed no obvious patterns in relation to productivity, although Mortier...

Beyond nature: The management of a productive cultural landscape in Las Médulas area (El Bierzo, León, Spain) during pre-Roman and Roman times

Abstract: This article focuses on the analysis of plant remains (seeds/fruits, charcoal, pollen, spores, and non-pollen palynomorphs) from two archaeological sites (pre-Roman and Roman) located in Las Medulas, a cultural landscape, in the northwestern part of the Iberian Peninsula. The article explores the way the communities living in the area managed their environment and the impact of productive activities on the landscape. This research has shown the multiplicity of needs this landscape satisfied and the various ways these communities managed the surrounding environment through different productive activities (agriculture, animal husbandry, and mining amongst others).

Leaf and root trait variability of alien and native species along Adriatic coastal dunes (Italy)

Abstract: This study regards the analysis of leaf and root trait variability of the most invasive alien species and some common native species developing along central‐southern Adriatic sand dunes in Italy. The results highlight that large leaf area, the reproductive period in late summer, a biennial/annual life cycle and thick, long roots are useful traits for the successful colonisation of the most invasive species Oenothera biennis, Erigeron canadensis and Xanthium orientale subsp. italicum along the mobile coastal dunes. These alien plants grow in spatial niches generated by eutrophication and human pressure, such as waste deposits on the beach and inter‐dune gaps, flattened and altered by human trampling. We suggest that exotic species in the study area are currently occupying temporal and spatial niches that are not being exploited by native species and, therefore, they are not competing directly for the same resources.

Effects of fragmentation on vascular plant diversity in a Mediterranean forest archipelago

Abstract: We analysed the effects of patch size and isolation on vascular plants in Quercus cerris forest surrounding Rome (Italy). We randomly sampled 96 plots within 18 forest patches with homogeneous environmental variables; the patches ranged from 1.4 ha to 424.5 ha and were divided into four size classes. We performed the analyses at the patch level using linear regression. At the size class level, the analysis of species richness response to fragmentation (area effect) was performed with ANOVA, while the effect on community composition was analysed by means of PERMANOVA. We also investigated which species could be used as indicator species for each size class. Lastly, to evaluate the advantages of conserving several small patches as opposed to few large ones, we used a cumulative area approach ranking forest fragments. The correlation between species richness and patch area was positive, with a significant difference between the “large” and “small” size classes, while analysis on community compositio...

Conservation genetics of small relic populations of silver fir (Abies alba Mill.) in the northern Apennines

Abstract: Small and isolated silver fir populations from the Emilian Apennines (northern Italy) were studied to assess their level of genetic variation and their relationship with Alpine populations. We investigated the variability of two chloroplast microsatellites to analyse the within‐population genetic variability of four peripheral and fragmented Apennine populations and to determine their phylogenetic relatedness to seven Alpine populations covering the entire distribution of silver fir in the Alps. Haplotypic richness and haplotype diversity as well as the fraction of private haplotypes were lower in Apennine populations, evidencing the genetic impoverishment of these stands. The among‐population genetic variability analysis revealed the genetic peculiarity of Apennine populations. Analysis of molecular variance showed that the highest level of the among‐population variation occurs between Alpine and Apennine regions. A neighbour‐joining dendrogram revealed a distinct Apennine cluster that included ...

Reworking the idea of chestnut (Castanea sativa Mill.) cultivation in Roman times: New data from ancient Campania

Abstract: Charcoal analysis was carried out in two archaeological sites on the north slope of the Somma-Vesuvius volcano, not far from Naples. Both sites were inhabited between the 2nd century AD and AD 472, when a great Vesuvius eruption (so called Pollena eruption) buried them. In both sites, Castanea sativa wood was largely used for architectural structures as well as firewood. Ten 14C dates, spanning between the 1st and the 5th century AD, testify to a continuative use of this wood throughout the life of the sites. The comparison between archaeobotanical and pollen data from other sites in southern Italy suggests that chestnut woods were close to the sites studied and had a restricted spreading, possibly in a refugium area on Vesuvius' foothills. The match between archaeological charcoals and pollen data suggests that the Romans did not spread chestnut cultivation in the entire Campania region and that chestnut probably became a common timber in Campania starting from the 5th–6th century AD.

Stand characteristics and biodiversity indicators along the productivity gradient in boreal forests: Defining a critical set of indicators for the monitoring of habitat nature quality

Abstract: We quantified the effects of anthropogenic disturbances on the structure and biodiversity of boreal forests on acidic soils and created a statistically supported rational set of indicators to monitor the stand “naturalness”. For that, we surveyed various traits of tree layer, understory, herb layer, forest floor and several widely accepted biodiversity epiphytic indicators in 252 old‐aged boreal stands in Estonia, mostly dominated by Scots pine or Norway spruce. Multifactorial general linear model analyses showed that many forest characteristics and potential indicators were confounded by the gradient of soil productivity (reflected by the forest site type), local biogeographic gradients and also by stand age. Considering confounding effects, boreal forests in a near‐natural state have more large‐diameter trees (diameter at breast height >40 cm) and larger variety of diameter classes, higher proportion of spruce or deciduous trees, a larger amount of coarse woody debris in various stages, a more ...

Root halotropism: Salinity effects on Bassia indica root

Abstract: Plant roots are responsible for the acquisition of nutrients and water from the soil and have an important role in plant response to soil stress conditions. The direction of root growth is gravitropic in general. Gravitropic responses have been widely studied; however, studies about other root tropisms are scarce. Soil salinity is a major environmental response factor for plants, sensed by the roots and affecting the whole plant. Our observations on root architecture of Kochia (Bassia indica) indicated that salinity may cue tropism of part of the roots toward increasing salt concentrations. We termed this phenomenon “positive halotropism”. It was observed that Kochia individuals in the field developed horizontal roots, originating from the main tap root, which was growing toward saline regions in the soil. Under controlled conditions in greenhouse experiments, Kochia plants were grown in pots with artificial soil salinity gradients, achieved by irrigation with saline and fresh water. It was shown...

Impacts of alien plants and man‐made disturbance on soil‐growing bryophyte and lichen diversity in coastal areas of Sardinia (Italy)

Abstract: Seventy phytosociological releves were performed in 1 m × 1 m plots at 14 study sites spread along sandy shores in northern and southern Sardinia (Italy). The plots were selected in different habitat types (open dunes, native Juniperus woodlands, maquis, and plantations with Acacia, Eucalyptus and Pinus) according to a stratified sampling method in order to investigate impacts deriving from different levels of Carpobrotus spp. cover, dry litter from exotic trees, and other disturbance types. The quantile regression and logistic regression analyses revealed that the reduction in the amount of bryophyte and lichen cover on sand dunes of the study area is caused either by a high cover of Carpobrotus spp. mats or by a high cover of dry exotic litter in dense, unmanaged or poorly managed forest plantations. Additional detrimental effects are often driven by other kinds of man‐made disturbances. Forest management in the coastal areas of Sardinia should be gradually modified to take into account the con...

Genetic structure and introgression in riparian populations of Populus alba L.

Abstract: White poplar (Populus alba) is a widespread species of the northern hemisphere. Introgressed populations or hybrid zones with the related species of the European aspen (Populus tremula) have been suggested as potential venues for the identification of functionally important variation for germplasm conservation, restoration efforts and tree breeding. Data on the genetic diversity and structure of introgressed P. alba are available only for sympatric populations from central Europe. Here, clonality, introgression and spatial genetic patterns were evaluated in three riparian populations of P. alba along the Ticino, Paglia‐Tevere and Cesano river drainages in Italy. Samples of all three populations were typed for five nuclear microsatellite markers and 137 polymorphic amplified fragment length polymorphisms. Microsatellite‐based inbreeding co‐efficients (F IS) were significantly positive in all three populations. Genetic diversity was consistently highest in Ticino, the population with the highest le...

Coastal salt‐marsh zonation in Tyrrhenian central Italy and its relationship with other Mediterranean wetlands

Abstract: The spatial patterns of salt‐marsh vegetation in the central Mediterranean district (Tyrrhenian central Italy) were analysed by establishing the plant‐community distribution in the Orbetello Lagoon and then carrying out a comparative analysis with other halophytic wetlands belonging to the western Mediterranean district. Floristic sampling was performed in the Orbetello Lagoon through belt transects. Cluster analyses revealed two main vegetation groups centred around Sarcocornia fruticosa and Atriplex portulacoides, and seven plant communities belonging to Sarcocornietea fruticosae and Juncetea maritimi phytosociological classes. The analysis of spatial pattern confirmed the classification results showing a typical plant zonation ranging from Sarcocornia communities in the lower areas of the lagoon to rushes dominated by Juncus acutus in more elevated areas. Alterations to this pattern may indicate the presence of disturbance (Aetheorhiza bulbosa community) or a geomorphological discontinuity (Li...

Geographical variation in morphology of Quercus petraea (Matt.) Liebl. as related to drought stress

Abstract: Differences in phenotypic plasticity among six populations of Quercus petraea exposed to drought stress were examined. The study was performed as a common garden experiment with five‐year‐old seedl...

Floristic composition and spatial distribution assessment of montane mesophilous grasslands in the central Apennines, Italy: A multi-scale and diachronic approach

Abstract: Evaluation of past land use offers valuable information in seeking to understand the distribution patterns of plant communities, insofar as such activity may have altered soil features, causing anthropogenic soil patchiness and marked plant diversity both locally and regionally. This study sought to provide a general overview of the relationships between the different syntaxonomical units and the soil features in a sub-Mediterranean grassland landscape, starting from assessment of soil parameters. In addition, we wanted to verify whether soil features and hierarchical landscape assessments of grasslands under homogeneous grazing disturbance are sufficient to explain the floristic differentiation of the plant communities, and whether study of land use history helps explain the distribution patterns of these plant communities. A clear understanding of the relationships between environmental factors and the floristic composition of plant communities is a strong basis for future inquiries into how di...