Vegetation Descriptors Research Articles

Combining SMOS with visible and near/shortwave/thermal infrared satellite data for high resolution soil moisture estimates

Summary Sensors in the range of visible and near–shortwave–thermal infrared regions can be used in combination with passive microwave observations to provide soil moisture maps at much higher spatial resolution than the original resolution of current radiometers. To do so, a new downscaling algorithm ultimately based on the land surface temperature ( LST ) – Normalized Difference Vegetation Index (NDVI) – Brightness Temperature ( T B ) relationship is used, in which shortwave infrared indices are used as vegetation descriptors, instead of the more common near infrared ones. The theoretical basis of those indices, calculated as the normalized ratio of the 1240, 1640 and 2130 nm shortwave infrared (SWIR) bands and the 858 nm near infrared (NIR) band indicate that they are able to provide estimates of the vegetation water content. These so-called water indices extracted from MODIS products, have been used together with MODIS LST , and SMOS T B to improve the spatial resolution of ∼40 km SMOS soil moisture estimates. The aim was to retrieve soil moisture maps with the same accuracy as SMOS, but at the same resolution of the MODIS dataset, i.e., 500 m, which were then compared against in situ measurements from the REMEDHUS network in Spain. Results using two years of SMOS and MODIS data showed a similar performance for the four indices, with slightly better results when using the index derived from the first SWIR band. For the areal-average, a coefficient of correlation ( R ) of ∼0.61 and ∼0.72 for the morning and afternoon orbits, respectively, and a centered root mean square difference (cRMSD) of ∼0.04 m 3 m −3 for both orbits was obtained. A twofold improvement of the current versions of this downscaling approach has been achieved by using more frequent and higher spatial resolution water indexes as vegetation descriptors: (1) the spatial resolution of the resulting soil moisture maps can be enhanced from ∼40 km up to 500 m, and (2) more accurate soil moisture maps (in terms of R and cRMSD) can be obtained, especially in periods of high vegetation activity. The results of this study support the use of high resolution LST and SWIR-based vegetation indices to disaggregate SMOS observations down to 500 m soil moisture maps, meeting the needs of fine-scale hydrological applications.

Soil nematode assemblage responds weakly to grazer exclusion on a nutrient-rich seabird island

The effects of aboveground herbivores on plant-soil interactions are highly context dependent and a key underlying factor controlling this is thought to be nutrient availability. Here, we tested whether the effects of vertebrate grazing on the soil food web varied with nutrient availability and hypothesised that soil food web structure would be driven more by the exclusion of vertebrate grazers than by nutrient enrichment. An 8-year long grazer exclusion experiment was performed in grasslands on a small Scottish island near soil nutrient-enriching seabird colonies at the coast and in less fertile conditions inland. We investigated the trophic structure of the soil nematode assemblage as a proxy for soil food web structure. Across all eight study sites the bacterial energy channel was predominant over the fungal channel. Grazer exclusion strongly enhanced plant biomass accumulation and although this tended to be associated with a somewhat lower abundance of bacterial-feeders, this effect was non-significant and surprisingly weak given the observed changes aboveground. Indeed, plant species identity, diversity and dominance were, just as any other vegetation descriptor, weak predictors of nematode trophic structure. Instead, site specific conditions were important, despite the small island area and apparently homogenous sampling conditions.

Analysis of Genetical Diversity of Some of the Tetraploides Potato Cultivars Grown in Iran

The genetical diversity of potato, Solanum tuberosum was assessed using morphological traits. To verify, how this diversity is distributed among the main potato varieties grown in Iran. A total of eleven potato varieties, Ramose, Sante, Shepody, Marfona, Maradona, Milova, Santana, Boren, Cosima, Granola and Agria, were evaluated under vivo and situ experimental conditions in Isfahan, conditions, Iran. Seven phenological, floral and morphological vegetative aerial descriptors, Growth Rate = CGR, Net Assimilation Rate = NAR, Leaf Area Duration = LAD, Leaf Area Ratio = LAR and specific Leaf Area = SLA were recorded. The descriptors were evaluated by SAS Software and their means comparison by DMRT test. Certain defined groups were observed, indicating that the diversity of the cultivars are structured with a considerable morphological variation in between the varieties with a very high significant growth indices.

Guild composition and habitat use of voles in 2 forest landscapes in south‐eastern Norway

It is widely believed that intensive forestry has influenced small mammal population dynamics, and thereby the entire mammalian community in Fennoscandian boreal forests. The nature of these impacts on the different species is subject to debate. We live-trapped voles between 2006 and 2009 in 2 commercially harvested forests in south-eastern Norway. We investigated the variation in vole abundance among habitat types (e.g. mature forest and clear-cut) and the hypothesis that graminivorous species such as field voles (Microtus agrestis L.) benefit from clear-cuts at the expense of forest dwellers (i.e. the bank vole, Myodes glareolus Schreb.), using fine-scale descriptors of the ground vegetation. We could not find support for the hypothesis that field voles show a preference for clear-cuts, and their overall abundance was low, while bank voles were the dominant species in all habitat types, including clear-cuts in the peak and pre-peak years. We found a positive association between bank vole abundance and bilberry (Vaccinium myrtillus L.) availability rather than a specific habitat type. Low field vole density in clear-cuts might be due to variation in local productivity and ground vegetation as well as to large variation in the species temporal dynamics. The latter is particularly associated with the widespread decline of field voles in Scandinavia. Logging has the potential to negatively affect bank vole population dynamics because of the negative effect on bilberry development.

Factors affecting mammalian carnivore use of riparian ecosystems in Mediterranean climates

Riparian ecosystems serve as movement and dispersal corridors; however, the factors that determine their use by multiple species of carnivores remain unknown. Two hypotheses can explain carnivore presence in riparian ecosystems. Higher riparian plant richness, diversity, and structure provide the resources used by carnivores (resting sites, cover, and food). Alternatively, areas with higher water availability allow species to withstand water loss and thermal gradients in the high summer temperatures. In southern Portugal we surveyed 70 transects 2 km long along riparian ecosystems during the wet winter months and again in the dry summer months, recording signs of carnivore species and the environmental context in which they occurred (vegetation descriptors, surrounding landscape, and waterway type and condition). Five carnivore species used riparian ecosystems (stone marten [Martes foina], Eurasian badger [Meles meles], common genet [Genetta genetta], Egyptian mongoose [Herpestes ichneumon], and red fox [Vulpes vulpes]). Riparian ecosystems had a diverse and heterogeneous plant community with a mix of obligate riparian, Mediterranean sclerophyllous, and exotic species. Most carnivore species responded to water channel type and standing water availability in both seasons, except for the stone marten in the wet season, which uses areas with rich riparian vegetation. Our results suggest that the use of riparian ecosystems is linked to water availability that provides water, prey, and external temperature regulation.

Effect of slight vegetation degradation on soil properties in Brachypodium pinnatum grasslands

The interrelationship of soil and vegetation degradation is an emerging issue, where most studies have addressed severe degradation so far. We aimed at revealing changes in soil accompanying slight vegetation degradation in a case study involving xeromesophilous grasslands from Hungary. Slight degradation is of special interest here because the target community (Euphorbio pannonicae—Brachypodietum pinnati association) has great nature conservation value. Vegetation status was related to chemical and structural soil properties by principal component analysis and redundancy analysis. Vegetation conditions were assessed by species abundances and by fine-scale spatial structure, which is proposed here for soil-vegetation studies. Slight vegetation degradation clearly manifested itself in soil properties. Differences in vegetation status when assessed by species abundances were mirrored in chemical soil properties. When structural vegetation descriptors were used, a soil structure property (bulk density) was responsible for the segregation according to naturalness. Vegetation-soil relationships were more consistent over biogeographic regions, when vegetation structural descriptors were used. Differences in chemical soil properties reflected species abundance pattern, as was found in most non-grazing related degradation studies. However, changes to soil structure also accompanied slight degradation, and their importance was revealed when vegetation structure was taken into account.

Seleção de descritores vegetativos para caracterização de acessos de guariroba (Syagrus oleracea (Mart.) Becc.)

O presente trabalho teve como objetivo selecionar descritores morfológicos vegetativos e determinar sua importância relativa na caracterização de acessos de guariroba, assim como verificar a associação entre os descritores descartados e os demais. Foram avaliados 18 descritores morfológicos, sendo 8 relativos à folha e 10 ao estipe, em 36 acessos de guariroba do Estado de Goiás. Os dados foram submetidos à análise de variáveis canônicas, e o descarte dos descritores foi realizado tendo como base no autovalor, o qual não excedeu 0,70. Foram descartados 55% dos descritores, sendo 5 relativos à folha e 5 ao estipe. O descarte destes descritores não ocasionou perda de informações, por apresentaram correlações significativas com os descritores selecionados. A contribuição relativa dos descritores selecionados foi semelhante para A7A, ENI7180, DFBF, D0, CPC e DPC, sendo os descritores ENI70 e ENS70 os que apresentaram as menores contribuições.

Variability of forest edge effect on vegetation implies reconsideration of its assumed hypothetical pattern

Question: How do descriptors of forest vegetation (species richness and composition) respond to edge influence and do these response patterns fit to the two-zone pattern theoretically predicted and empirically observed? Location: District of Aurignac, southwestern France. Methods: We surveyed all understory forest vegetation along 28 transects pertaining to seven contrasted boundary types. Boundary types were a combination of adjacent land cover, orientation and topography classes. Response patterns to edge influence of two vegetation descriptors, species richness and composition (summarized by an ordination), were analysed using the two-phase linear regression method . Data for each transect were divided into all possible pairs of adjacent groups of successive plots, and a linear regression was computed on both groups of plots. Regression parameters were interpreted by comparison with the two-zone theoretical pattern and related to boundary types. Results: We have shown for nearly half of the transects that vegetation responses deviate from the two-zone pattern. There was no significant relationship between regression coefficients for richness and boundary characteristics whereas regression coefficients for composition were partly related to adjacent land cover. Conclusions: Our results demonstrate a high variability of forest vegetation response patterns to edge that contrasts with the theoretical pattern usually reported in the literature. Forest history and edge dynamics are invoked to explain the observed vegetation patterns. We have shown the need for a review of factors affecting the edge influence for better management and conservation of forest plant species.

Comportamento fitotécnico da bananeira 'Prata-Anã' e de seus híbridos

O objetivo deste trabalho foi avaliar o comportamento fitotécnico da bananeira 'Prata-Anã' e de quatro híbridos descendentes, em dois ciclos de produção, no Perímetro Irrigado do Estreito, sudoeste da Bahia. Utilizou-se o delineamento experimental inteiramente casualizado com cinco tratamentos: cultivar Prata-Anã e os híbridos Fhia-01 (BRS Fhia Maravilha), BRS Fhia-18, Fhia-18 e PA42-44, com dez repetições. Foram mensurados os descritores fenotípicos vegetativos, os de ciclo e os de rendimento. Foram observados os seguintes incrementos entre ciclos: na altura da planta, no perímetro do pseudocaule, no número de pencas e de frutos, e na produtividade. O híbrido Fhia-18 apresentou maior porte e perímetro do pseudocaule, a 'Prata-Anã' menor porte (com manutenção desse caráter no PA42-44). Os híbridos foram similares quanto ao número de filhos emitidos. Os híbridos BRS Fhia-18, Fhia-1 e PA42-44 foram mais precoces para a colheita e apresentaram frutos com maior comprimento que a genitora. Fhia-18 apresentou maior quantidade de frutos e PA42-44 menor número de pencas em comparação à genitora. Os híbridos BRS Fhia-18, Fhia-18 e Fhia-1 são mais produtivos que a genitora. 'Prata-Anã' é a mais suscetível à sigatoka-amarela, e PA42-44 é resistente e com maior retenção de folhas na colheita, porém, similar à genitora em produtividade.

Ecology and management of the lobster mushroom in an eastern Canadian jack pine stand

The lobster mushroom, an organism resulting from the infection of Russula spp. by Hypomyces lactifluorum (Schwein.) Tul. & C. Tul., is common to Canadian boreal forests and has good commercial potential. Within a Pinus banksiana Lamb. stand managed for mushroom production, this study aimed to (1) document carpophore productivity (density, biomass per area) during three seasons, (2) compare productivity among three forest conditions (trails, forest strips between trails, and unmanaged forest), (3) establish ecological parameters related to productivity, and (4) define microhabitats where carpophores are present by using soil and vegetation descriptors. Mushroom density tended to be higher on the trails than under the canopy, but fresh biomass was higher in forest strips except in 2006 when midsummer precipitation was low. Trail management did not increase mushroom production but maintained it during periods of reduced precipitation. Productivity was positively related to the abundance of shade-intolerant plant species and to extractable ammonium, and negatively related to soil pH. Within the present study conditions, microhabitats suitable for the presence of carpophores had low pH, high available phosphorus, low Kalmia angustifolia L. cover, and small canopy gaps with shade-intolerant species. This study was the first step toward understanding the ecology and impacts of forest practices on the lobster mushroom.

Forest structure in a mosaic of rainforest sites: The effect of fragmentation and recovery after clear cut

A variety of human-induced disturbances such as forest fragmentation and recovery after deforestation for pasture or agricultural activities have resulted in a complex landscape mosaic in the Una region of northeastern Brazil. Using a set of vegetation descriptors, we investigated the main structural changes observed in forest categories that comprise the major components of the regional landscape and searched for potential key descriptors that could be used to discriminate among different forest categories. We assessed the forest structure of five habitat categories defined as (1) interiors and (2) edges of large fragments of old-growth forest (>1000 ha), (3) interiors and (4) edges of small forest fragments (<100 ha), and (5) early secondary forests. Forest descriptors used here were: frequency of herbaceous lianas and woody climbers, number of standing dead trees, number of fallen trunks, litter depth, number of pioneer plants (early secondary and shade-intolerant species), vertical foliage stratification profile and distribution of trees in different diameter classes. Edges and interiors of forest fragments were significantly different only in the number of standing dead trees. Secondary forests and edges of fragments showed differences in litter depth, fallen trunks and number of pioneer trees, and secondary forests were significantly different from fragment interiors in the number of standing dead trees and the number of pioneer trees. Horizontal and vertical structure evaluated via ordination analysis showed that fragment interiors, compared to secondary forests, were characterized by a greater number of medium (25–35 cm) and large (35–50 cm) trees and smaller numbers of thin trees (5–10 cm). There was great heterogeneity at the edges of small and large fragments, as these sites were distributed along almost the entire gradient. Most interiors of large and small fragments presented higher values of foliage densities at higher strata (15–20 m and at 20–25 m height), and lower densities at 1–5 m. All secondary forests and some fragment edge sites showed an opposite tendency. A discriminant function highlighted differences among forest categories, with transects of large fragment interiors and secondary forests representing two extremes along a disturbance gradient determined by foliage structure (densities at 15–20 m and 20–25 m), with the edges of both large and small fragments and the interiors of small fragments scattered across the gradient. The major underlying processes determining patterns of forest disturbance in the study region are discussed, highlighting the importance of forest fragments, independently of its size, as forests recovery after clear cut show a greatly distinct structure, with profound implications on fauna movements.

A multi-site study to classify semi-natural grassland types

Calibration and validation of simulation models describing herbage growth or feed quality of semi-natural grasslands is a complex task for agronomists without investing effort into botanical surveys. To facilitate such modelling efforts, a limited number of grassland types were identified using a functional classification of species. These grassland types were characterized by three descriptors required to model herbage growth or feed quality: the abundance-weighted mean leaf dry matter content across grass species, the relative abundance of grasses, and an estimate of species richness. We conducted a multi-site analysis over 749 grasslands from eight temperate regions in France and northern Spain. Using Restricted Maximum Likelihood models, explanatory variables having a significant impact on the descriptors of grassland vegetation were identified. These were management type and nutrients availability described either with an ecological approach based on Ellenberg nutrient indices, or an agronomic approach based on plant nutrition indices. By fixing expert-assigned boundaries along the gradients of management type and nutrients availability, we identified a classification of 3 × 3 semi-natural grassland types. When compared pairwise with a Kruskal–Wallis test, the identified semi-natural grassland types showed significant differences for vegetation descriptors. The model inputs corresponding to different semi-natural grassland types led to simulated differences in herbage growth and feed quality comparable with the uncertainty on the model output. This confirmed the relevance of the classification based only on nine species-rich semi-natural grassland types easily identifiable on the field to model herbage growth or feed quality.

The composition and richness of Danubian floodplain forest land snail faunas in relation to forest type and flood frequency

The species richness and composition of land snail assemblages in 42 floodplain forest sites along the Danube River in Slovakia were studied to find the main ecological gradients responsible for the variation in the faunas. We found just one, but steep, ecological gradient influencing the variation of snail species composition among different floodplain forest types, reflected in the first detrended correspondence analysis axis, which explained 29.6% of total variation. Site scores on this axis were significantly correlated with site humidity (rs ¼ 20.868; P , 0.001). Significant loading on the first axis was also found for flood frequency and several vegetation descriptors. Species composition mainly reflected differences between sites without floods and the others. Species richness as well as total abundances of live individuals were not significantly controlled by any explanatory variable, although some trends could be discerned. Considering vegetation classification, substantial differences were observed between wet softwood floodplain forests and the remaining types, drier softwood forests and different types of hardwood forests, which were impossible to distinguish based on land snail assemblages. The results are discussed in relation to earlier descriptive studies, and in terms of the conservation of these threatened habitats.

Alien species importance in native vegetation along wadeable streams, John Day River basin, Oregon, USA

We evaluated the importance of alien species in existing vegetation along wadeable streams of a large, topographically diverse river basin in eastern Oregon, USA; sampling 165 plots (30 × 30 m) across 29 randomly selected 1-km stream reaches. Plots represented eight streamside community types associated with varying elevation, precipitation, and landform. Mantel comparisons, non-metric multidimensional scaling (NMS), and Spearman correlation identified relationships of alien species (n = 60) distribution and relative alien cover (RAC) to native species (n = 355) composition, 28 vegetation descriptors, 31 environmental variables, and 30 disturbance conditions. Alien species occurred in 93% of sample plots, in all community types, and along all sampled stream reaches; with RAC ranging from 0.1% to 47% and 1 to 24 alien species occurring along individual stream reaches. Alien richness and RAC were positively related to native diversity where invasion was limited (RAC 5%). RAC differed among community types: greatest in arid associations (shrubland/grassland), followed by associations with limited tree canopy cover (meadows, dry forest), and lowest in moist, closed forest associations; suggesting differences in invasion status or vulnerabilities to alien invasion among community types. Alien species, as a group had wider ecological amplitude than natives, and species composition among community types was less distinct when both alien and natives were considered compared to native species only. RAC was negatively related to elevation, precipitation, and tree cover; while positive relationships of RAC occurred with grazing pressure, upstream watershed size, stream order, overall level of exogenous disturbance, limited vegetated buffer, agriculture in the upstream watershed, floodplain or south facing slope locations, and proximity to roads. Taken together, these results suggest possible ecological consequences to streamside vegetation related to alien species and identify indicators of conditions, where invasion may be greatest, offering potential for informing decisions for monitoring and managing alien species.

Grazing management impacts on the viability of the threatened bog fritillary butterfly Proclossiana eunomia

Management of semi-natural open ecosystems has become a necessity for biodiversity conservation in Europe. However, management methods are most often experience-based, rather than science-based. Here, we explore the impact of extensive (light) grazing, which is often the only practical management solution to stop ecological succession towards forest. A metapopulation of the bog fritillary butterfly ( Proclossiana eunomia), a wet meadow specialist, was monitored for 15 generations: 11 before and four after the introduction of cattle grazing in some habitat patches. We relate the observed changes in P. eunomia abundance and recruitment to the effect of grazing on vegetation descriptors linked to habitat quality for the butterfly. Cattle strongly decreased the abundance of the butterfly host plant, destroyed grass tussocks used by caterpillars for sun basking, and altered vegetation composition and physiognomy. Consequently, grazed habitat patches are less suitable for P. eunomia: recruitment rate and butterfly use decreased by 2/3, whereas emigration rate increased drastically; this is likely to alter the viability of the metapopulation. We therefore propose modifications to its current implementation to limit its negative side-effects. More generally, it is of prime importance that conservation biologists and site managers collaborate in ensuring that sound ecological evaluations become an integral part of the design and application of management plans. This implies the monitoring of crucial indicators of the system state and variability before the beginning of the management, and the maintenance of unmanaged areas as biological preserves in case of negative impact and as controls for statistical tests of impact.

Inferring the effect of plant and soil variables on C- and L-band SAR backscatter over agricultural fields, based on model analysis

The goal of this study was to extract from dual-frequency satellite SAR signatures consistent information about moisture in soils and about various features of plants for analyzing crop growth conditions in any agricultural region. The study was carried out on Polish agricultural regions but it is hoped that it will be applicable anywhere on the planet. During a satellite overpass on a particular date, the ground-based measurements required such as soil moisture (SM), Leaf Area Index (LAI), and biomass were collected from 10 to14 May 1998. The backscattering coefficients at various frequencies were collected from ERS-2.SAR (C-VV) on May 10, 1998 and from JERS-SAR (L-HH) on May 14, 1998. The applicability of three different vegetation descriptors to the semi-empirical water-cloud model was investigated. The contribution to the backscatter values of vegetation features such as leaf area expressed in the Leaf Area Index and the dielectric properties of leaf surface expressed in the Leaf Water Area Index (LWAI) and the Vegetation Water Mass (VWM) was examined in order to reveal the best fit of the model. It was found that in C-band, which had an incidence angle of 23°, the soil moisture contribution to the sigma value was predominant over the vegetation contribution. When the canopy cover increases, the sensitivity of a radar signal to dry soil conditions ( SM < 0.1) decreased. The sigma value was the most sensitive to vegetation descriptor VWM which described the amount of water in vegetation. Attenuation of soil signal by the canopy was found in all three vegetation descriptors types; the strongest attenuation effect was observed in the case of VWM. In L-band (where the incidence angle was 35°), the dominant signal to total σ o value comes from volume scattering of vegetation for LAI > 3. When LAI < 3 the vegetation contribution to total σ o value appeared in two-way attenuation. The results gave us the possibility of comparing the modeled with the measured soil and vegetation parameters.

Bird communities in suburban patches near Paris: Determinants of local richness in a highly fragmented landscape

:Local species richness in highly fragmented landscapes is expected to be affected by characteristics of both the considered patch and its surrounding matrix, especially in areas dominated by human activities. However, the proximity of other suitable habitat patches may also be determinant for the conservation of biodiversity by enhancing dispersal and thus, “rescue effects” and re-colonization. We investigated breeding bird communities on 63 patches suitable for wildlife in the suburbs of Paris, France, in 2003. After exploring the spatial structure of the data, we tested hypotheses relating local species richness to patch characteristics (size and vegetation), urbanization intensity around patches, and patch isolation relative to the nearest natural remnant. Spatial dependence in the data was considered in the regression analyses because patch distribution may affect local species richness through ecological processes and non-independence between patches situated nearby can pose statistical problems. Fifty-seven regular breeding bird species were recorded over the entire study area. Local bird species richness, patch size and vegetation descriptors were not spatially autocorrelated. Conversely, urbanization intensity around the patches and patch isolation were spatially autocorrelated. Species richness was mainly related to patch size and to the diversity of trees and shrubs, while neither herbaceous plants nor patch distance to the nearest large forest remnant had significant effects. Moreover, we found that the degree of urbanization around patches did not provide a strong predictor of bird richness, which is more newsworthy. Overall, this study stresses once more the complexity of factors and processes responsible of community patterns in urban landscapes. It also highlights the need to explicitly consider spatial issues when investigating these patterns.

THE HIGH-ELEVATION POPULATION OF MOUNTAIN PLOVERS IN COLORADO

Abstract We surveyed a discrete population of Mountain Plovers (Charadrius montanus) in South Park, Park County, Colorado, to determine the size and relative contribution of this geographically isolated area to the global population of plovers. First, we mapped potential plover habitat within South Park based on landform and vegetation descriptors. Second, we identified occupied habitat using observations from a systematic inventory of potential habitat from 1995–1999 and from a study of breeding biology from 2000–2002. Third, we estimated breeding densities within a framework designed specifically for distance sampling. We mapped 82 750 ha of potential habitat. We recorded 2516 plover locations from which we estimated 29 176 ha of occupied habitat. We estimated densities for 14 960 ha of potential habitat. Average plover density from 2000–2002 was 7.9 ± 0.9 (SE) breeding adults km−2, a high value compared with other sites. We calculated a population of 1187 ± 140 (SE) plovers in the distance sampling are...

A geomorphic approach to global classification for inland wetlands

A geomorphic classification of inland wetlands on criteria other than vegetation is proposed, based on their host landform and degree of wetness. Thus, the classification addresses the underlying structure of most inland wetlands, i.e. their landform setting and their various types of hydroperiod. Landforms host to wetlands include: basins, channels, flats, slopes and hills/highlands. Degrees of wetness include: permanent, seasonal or intermittent inundation, and seasonal waterlogging. From combining the landform type with hydroperiod, thirteen primary types of common wetlands are recognized: 1. permanently inundated basin = lake; 2. seasonally inundated basin = sumpland; 3. intermittently inundated basin = playa; 4. seasonally waterlogged basin = dampland; 5. permanently inundated channel = river; 6. seasonally inundated channel = creek; 7. intermittently inundated channel = wadi; 8. seasonally waterlogged channel = trough; 9. seasonally inundated flat = floodplain; 10. intermittently inundated flat = barlkarra; 11. seasonally waterlogged flat = palusplain; 12. seasonally waterlogged slope = paluslope; and 13. seasonally waterlogged highlands = palusmont. Water, landform and vegetation descriptors can augment the nomenclature of the primary units: e.g. salinity of water; size and shape of landform; and organisation, structure and floristics of vegetation. The classification can be used in many settings, regardless of climate and vegetation types. Using the approach adopted in this classification, in principle, more landform types and degrees of wetness, if necessary, can be added to the system to define additional wetland types.

Relation of the consumptive use coefficient to the description of vegetation

Evapotranspiration from three reaches of the Gila River floodplain in Arizona was measured by the water budget during 1963–1971. Initially, the vegetation consisted of salt cedar and mesquite with densities of canopy ranging from 10 to 100%. The phreatophytes were removed from the study reaches in stages during 1967–1971. Perennial grass seed was applied but did not become established, and the postclearing vegetation was primarily annuals. Comparison of the evapotranspiration data from various reaches and comparison of data from before and after clearing required the application of an empirical equation. A consumptive use coefficient related to the description of vegetation was applied to an existing potential evapotranspiration equation based on macroclimatic observations. Initially, the vegetation description consisted of plant identification and canopy dimensions obtained by use of black and white aerial photography and ground measurements. In 1967, remote sensing in the form of color infrared aerial photography became available and densitometric interpretation was used to develop a spectral signature as the vegetation descriptor.