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Native Vegetation (native + vegetation)

Distribution by Scientific Domains

Life Sciences	69%
Earth and Environmental Science	18%
Engineering	6%

Selected Abstracts

Regional Planning in Queensland's Rangelands: Challenges and Prospects for Biodiversity Conservation

GEOGRAPHICAL RESEARCH, Issue 1 2007
CLIVE A. MCALPINE
Abstract In Australia, the Commonwealth and State governments are increasingly devolving natural resource management (NRM) responsibilities to regional bodies. This move has led to the development of regional NRM plans. Native vegetation and biodiversity conservation, along with soil, pasture and water resources, are key components of the regional NRM plans in Queensland's extensive rangelands. This paper outlines and applies a set of criteria for evaluating the native vegetation and biodiversity content of accredited regional NRM plans for Queensland's rangelands. The evaluation showed considerable variation in the comprehensiveness of the information and knowledge base and management action targets among plans, including the poor articulation of impacts of excessive grazing pressure on biodiversity. The NRM plans lacked effective integration of natural resource, native vegetation and biodiversity conservation targets and actions. Several regions had too many biodiversity targets, many of which were poorly integrated. This is symptomatic of a limited understanding of rangelands as ecological systems and the lack of an integrated planning framework. We conclude regional NRM planning is not a ,silver bullet' for biodiversity conservation in the rangelands, but rather, it is the beginning of a long road to address complex, multi-scale problems at a regional level. [source]

Establishment of native perennial shrubs in an agricultural landscape

AUSTRAL ECOLOGY, Issue 6 2007
NATHAN K. WONG
Abstract Native vegetation has been destroyed or dramatically modified throughout agricultural regions of southern Australia. Extensive restoration of native perennial vegetation is likely to be crucial in these areas for the persistence of native plant and animal species, to ameliorate dryland salinity and soil degradation, and to maintain long-term agricultural production. The long-term resilience of these systems will be dependent on the ability of key functional taxa, such as perennial shrubs, to recruit and persist. In this study, we examine the factors limiting establishment of two perennial shrubs in formerly cropped land, the rare Maireana rohrlachii and the common Maireana decalvans. Field and laboratory observations suggest that establishment of both species is not limited by life-history traits following cultivation. Both species established and persisted under varying levels of plant competition. Similarities existed between species in their initial germination rates. Weak differences were found between species in the growth and survival rates under different levels of competition. The main difference between the two species was in the decline of germinability of fruits with increasing fruit age. From the data, it is difficult to determine what factors limit the establishment of perennial shrubs in these landscapes. The main hypothesis that can be advanced is that establishment of shrub species appears to be limited by propagule availability and this is likely to be a function of past and present grazing management rather than cultivation per se. Further investigation of these land-use practices may give greater insight into the factors affecting the establishment of this life form across these landscapes. [source]

Native saltbush (Rhagodia spp.; Chenopodiaceae) as a potential reservoir for agromyzid leafminer parasitoids on horticultural farms

AUSTRALIAN JOURNAL OF ENTOMOLOGY, Issue 1 2010
Glenys Wood
Abstract Australia has to date been spared the introduction of highly polyphagous invasive pest agromyzid leafminers; however, their arrival and spread should be considered imminent. To develop a pre-emptive control strategy to deal with exotic leafminer outbreaks the first step is to identify Australian leafmining flies, their plant hosts and their parasitoids to gain an understanding of their population dynamics. Native vegetation may be providing resources for beneficial parasitic wasps plus access to alternative hosts and refuge from disturbance. Here, two Australian endemic saltbushes (Rhagodia candolleana and R. parabolica, Caryophyllales: Chenopodiaceae) have been investigated for their potential to act as reservoirs for endemic agromyzid hosts and their key parasitoids. Mined leaves of the two Rhagodia species were sampled on two commercial horticultural properties in the Virginia horticulture area on the Northern Adelaide Plains between September 2007 and April 2008. Leaf mines on both Rhagodia species were caused by an endemic leafminer species, putatively Phytoliriomyza praecellens Spencer (Diptera: Agromyzidae). Ten species of parasitoids (all Hymenoptera) emerged from R. candolleana mines and seven different species from R. parabolica mines, mainly from the family Eulophidae and with some Pteromalidae and Braconidae. Trigonogastrella Girault sp. (Pteromalidae), Zagrammosoma latilineatum Ubaidillah and Hemiptarsenus varicornis Girault (both Eulophidae) were the most abundant species on R. candolleana, whereas two Opius Wesmael spp. (Braconidae) were the most abundant species on R. parabolica. Findings from this survey suggest an opportunity to plant purpose-designed refuges that could play a role in conservation biological control as part of an Integrated Pest Management strategy developed prior to incursion of pest leafminers such as Liriomyza species. [source]

Extinction debt on oceanic islands

ECOGRAPHY, Issue 2 2010
Kostas A. Triantis
Habitat destruction is the leading cause of species extinctions. However, there is typically a time-lag between the reduction in habitat area and the eventual disappearance of the remnant populations. These "surviving but ultimately doomed" species represent an extinction debt. Calculating the magnitude of such future extinction events has been hampered by potentially inaccurate assumptions about the slope of species,area relationships, which are habitat- and taxon-specific. We overcome this challenge by applying a method that uses the historical sequence of deforestation in the Azorean Islands, to calculate realistic and ecologically-adjusted species,area relationships. The results reveal dramatic and hitherto unrecognized levels of extinction debt, as a result of the extensive destruction of the native forest:>95%, in<600,yr. Our estimations suggest that more than half of the extant forest arthropod species, which have evolved in and are dependent on the native forest, might eventually be driven to extinction. Data on species abundances from Graciosa Island, where only a very small patch of secondary native vegetation still exists, as well as the number of species that have not been found in the last 45,yr, despite the extensive sampling effort, offer support to the predictions made. We argue that immediate action to restore and expand native forest habitat is required to avert the loss of numerous endemic species in the near future. [source]

Wide-area estimates of saltcedar (Tamarix spp.) evapotranspiration on the lower Colorado River measured by heat balance and remote sensing methods,,

ECOHYDROLOGY, Issue 1 2009
Pamela L. Nagler
Abstract In many places along the lower Colorado River, saltcedar (Tamarix spp) has replaced the native shrubs and trees, including arrowweed, mesquite, cottonwood and willows. Some have advocated that by removing saltcedar, we could save water and create environments more favourable to these native species. To test these assumptions we compared sap flux measurements of water used by native species in contrast to saltcedar, and compared soil salinity, ground water depth and soil moisture across a gradient of 200,1500 m from the river's edge on a floodplain terrace at Cibola National Wildlife Refuge (CNWR). We found that the fraction of land covered (fc) with vegetation in 2005,2007 was similar to that occupied by native vegetation in 1938 using satellite-derived estimates and reprocessed aerial photographs scaled to comparable spatial resolutions (3,4 m). We converted fc to estimates of leaf area index (LAI) through point sampling and destructive analyses (r2 = 0·82). Saltcedar LAI averaged 2·54 with an fc of 0·80, and reached a maximum of 3·7 with an fc of 0·95. The ranges in fc and LAI are similar to those reported for native vegetation elsewhere and from the 1938 photographs over the study site. On-site measurements of water use and soil and aquifer properties confirmed that although saltcedar grows in areas where salinity has increased much better than native shrubs and trees, rates of transpiration are similar. Annual water use over CNWR was about 1·15 m year,1. Copyright © 2008 John Wiley & Sons, Ltd. [source]

Local hydrologic effects of introducing non-native vegetation in a tropical catchment

ECOHYDROLOGY, Issue 1 2008
Maite Guardiola-Claramonte
Abstract This study investigates the hydrologic implications of land use conversion from native vegetation to rubber (Hevea brasiliensis) in Southeast Asia. The experimental catchment, Nam Ken (69 km2), is located in Xishuangbanna Prefecture (22°N, 101°E), in the south of Yunnan province, in southwestern China. During 2005 and 2006, we collected hourly records of 2 m deep soil moisture profiles in rubber and three native land-covers (tea, secondary forest and grassland), and measured surface radiation above the tea and rubber canopies. Observations show that root water uptake of rubber during the dry season is controlled by day-length, whereas water demand of the native vegetation starts with the arrival of the first monsoon rainfall. The different dynamics of root water uptake in rubber result in distinct depletion of soil moisture in deeper layers. Traditional evapotranspiration and soil moisture models are unable to simulate this specific behaviour. Therefore, a different conceptual model, taking in account vegetation dynamics, is needed to predict hydrologic changes due to land use conversion in the area. Copyright © 2008 John Wiley & Sons, Ltd. [source]

The role of floristic survey data and quantitative analysis in identification and description of ecological communities under threatened species legislation: A case study from north-eastern New South Wales

ECOLOGICAL MANAGEMENT & RESTORATION, Issue 2009
Penny Kendall
Summary The concept of ecological communities play an important role in conservation planning and natural resource management. However, inherent uncertainties in the definition and identification of individual communities make it difficult to assess whether particular communities are present on particular sites and how they may be affected by proposed developments or management actions. If communities are poorly defined or misidentified, they may not perform their intended role as effective representations of biodiversity. We use a case study of forest communities dominated by Brown Barrel (Eucalyptus fastigata) in north-eastern New South Wales to demonstrate the value of quantitative floristic survey data for resolving robust and effective classifications of communities. Numerical analyses of an extensive set of floristic data suggested a re-configuration of a prior classification based largely on subjective interpretation. Although the general existence of assemblages dominated by Brown Barrel was confirmed, the new classification replaced three prior units with two assemblages that were more robust and better reflected the overall patterns in species composition. As only one of the two assemblages potentially warranted threatened status, the new classification allows scarce conservation resources to be targeted where they are most needed. The quantitative survey data also enabled a more detailed floristic description of the assemblages and provided a basis for maps of point locations and modelled habitat. These maps identified previously undocumented occurrences of the communities and helped to assess their extent of decline since European settlement. Improving the coverage of quadrat-based floristic sampling is therefore a valuable and cost-effective investment to inform better management of native vegetation and biodiversity. [source]

Modelling rising groundwater and the impacts of salinization on terrestrial remnant vegetation in the Blackwood River Basin

ECOLOGICAL MANAGEMENT & RESTORATION, Issue 1 2004
Geoff Hodgson
Summary Southwest Western Australia has a particularly rich biodiversity. Clearing for agriculture has greatly reduced the extent of native vegetation in wheatbelt catchments; it also set into train hydrogeological and hydrological changes that are still evolving toward a new equilibrium. With those changes come widespread land salinization that presents a further risk to remnant vegetation, particularly in low portions of the landscape. The equilibrium position of shallow groundwater was modelled for the Blackwood Catchment, and used to assess the extent of risk to a set of remnant vegetation classes. A total of 37 368 ha of remnant vegetation was identified to be at risk of salinization when hydrological equilibrium is reached. Further hydrological modelling assessed the rate of development of these watertables (and hence the rate of impact on remnants), as well as the potential to protect remnants by controlling groundwater recharge with revegetation. The results demonstrate that only high levels of revegetation are effective at protecting high value remnants in the longer term. The timing of events is dependant on the accuracy of estimating recharge. [source]

Organic phosphorus speciation and pedogenesis: analysis by solution 31P nuclear magnetic resonance spectroscopy

EUROPEAN JOURNAL OF SOIL SCIENCE, Issue 6 2007
R. W. McDowell
Summary Changes in phosphorus (P) during soil development are central to the understanding of labile P for plant productivity and soil P management. We used NaOH-EDTA extraction with 31P nuclear magnetic resonance spectroscopy (31P NMR), sequential P fractionation, and general soil chemical characterization to better our understanding of P dynamics within two chronosequences (Manawatu and Reefton) and one Basalt maturity sequence under original native vegetation. With time, orthophosphate and orthophosphate monoesters tended to increase with organic C to a maximum of about two-thirds of NaOH-EDTA-extractable P in young soils (16 000 years in the Reefton chronosequence), but gradually declined thereafter to about one-third of NaOH-EDTA-extractable P in the oldest soils (130 000 years old). This coincided with a depletion of P from primary minerals (e.g. apatite) and readily available P for plant production. This depletion of inorganic P resulted in a greater reliance on organic P cycling via mineralization, hence the depletion of the normally recalcitrant monoester-P pool. Concomitantly, the build-up of labile P species (diesters and pyrophosphate) and scyllo - over myo -inositol hexakisphosphate occurred as soils developed, and might be attributed to microbial activity, including scavenging for P. This work highlights the importance of organic P cycling during pedogenesis. [source]

Analysis of the distribution of Phytophthora cinnamomi in soil at a disease site in Western Australia using nested PCR

FOREST PATHOLOGY, Issue 2 2009
N. Williams
Summary The oomycete plant pathogen Phytophthora cinnamomi has infected a very large area of native vegetation in the south western corner of Australia. An important aspect of effective disease management depends on being able to accurately map areas of infestation. For this purpose, we have developed a nested polymerase chain reaction (PCR) protocol for the detection of P. cinnamomi in soil. The test uses two sets of primers developed from the rRNA ITS sequences of P. cinnamomi and can detect as little as 1 pg DNA. The degree of sensitivity was reduced with DNA extracted from soil although this depended on the type of soil. Soils with a high organic content, such as eucalypt forest soil and potting mix were more inhibitory than sandy soils. Inhibition by soil DNA could be reduced by the addition of bovine serum albumin and formamide to the reaction. Taq DNA polymerase was very sensitive to inhibitors compared with Tth+ or TaqF1*. In comparison with baiting (0,10% positive samples), nested PCR proved to be a very much more efficient (90,100% positive samples) method for the detection of P. cinnamomi in soil. [source]

Similar breakdown rates and benthic macroinvertebrate assemblages on native and Eucalyptus globulus leaf litter in Californian streams

FRESHWATER BIOLOGY, Issue 4 2010
IGOR LA
Summary 1.,Eucalyptus globulus, a tree species planted worldwide in many riparian zones, has been reported to affect benthic macroinvertebrates negatively. Although there is no consensus about the effects of Eucalyptus on aquatic macrobenthos, its removal is sometimes proposed as a means of ecological restoration. 2.,We combined the sampling of macroinvertebrates with measurement of the colonisation of leaf packs in mesh bags, to examine the effects of riparian Eucalyptus and its litter on benthic macroinvertebrates in three small streams in California, U.S.A. Each stream included one reach bordered by Eucalyptus (E-site) and a second bordered by native vegetation (N-site). 3.,The macrobenthos was sampled and two sets of litter bags were deployed at each site: one set with Eucalyptus litter (Euc-bags) and one with mixed native tree litter (Nat-bags) containing Quercus, Umbellularia, Acer and Alnus. Bags were exposed for 28, 56 and 90 days and this experiment was repeated in the autumn, winter and spring to account for effects of changing stream flow and insect phenology. 4.,Litter input (average dry mass: 950 g m,2 year,1 in E-sites versus 669 g m,2 year,1 in N-sites) was similar, although in-stream litter composition differed between E- and N-sites. Litter broke down at similar rates in Euc-bags and Nat-bags (0.0193 day,1 versus 0.0134 day,1), perhaps reflecting the refractory nature of some of the leaves of the native trees (Quercus agrifolia). 5.,Summary metrics for macroinvertebrates (taxon richness, Shannon diversity, pollution tolerance index) did not differ significantly between the E and N sites, or between Euc-bags and Nat-bags. No effect of exposure time or site was detected by ordination of the taxa sampled. However, distinct seasonal ordination clusters were observed in winter, spring and autumn, and one of the three streams formed a separate cluster. 6.,The presence of Eucalyptus was less important in explaining the taxonomic composition of the macrobenthos than either ,season' or ,stream'. Similarly, these same two factors (but not litter species) also helped explain the variation in leaf breakdown. We conclude that patches of riparian Eucalyptus and its litter have little effect on stream macrobenthos in this region. [source]

Regional Planning in Queensland's Rangelands: Challenges and Prospects for Biodiversity Conservation

High rates of net ecosystem carbon assimilation by Brachiara pasture in the Brazilian Cerrado

GLOBAL CHANGE BIOLOGY, Issue 5 2004
Alexandre J.B. Santos
Abstract To investigate the consequences of land use on carbon and energy exchanges between the ecosystem and atmosphere, we measured CO2 and water vapour fluxes over an introduced Brachiara brizantha pasture located in the Cerrado region of Central Brazil. Measurements using eddy covariance technique were carried out in field campaigns during the wet and dry seasons. Midday CO2 net ecosystem exchange rates during the wet season were ,40 ,mol m,2 s,1, which is more than twice the rate found in the dry season (,15 ,mol m,2 s,1). This was observed despite similar magnitudes of irradiance, air and soil temperatures. During the wet season, inferred rates of canopy photosynthesis did not show any tendency to saturate at high solar radiation levels, with rates of around 50 ,mol m,2 s,1 being observed at the maximum incoming photon flux densities of 2200 ,mol m,2 s,1. This contrasted strongly to the dry period when light saturation occurred with 1500 ,mol m,2 s,1 and with maximum canopy photosynthetic rates of only 20 ,mol m,2 s,1. Both canopy photosynthetic rates and night-time ecosystem CO2 efflux rates were much greater than has been observed for cerrado native vegetation in both the wet and dry seasons. Indeed, observed CO2 exchange rates were also much greater than has previously been reported for C4 pastures in the tropics. The high rates in the wet season may have been attributable, at least in part, to the pasture not being grazed. Higher than expected net rates of carbon acquisition during the dry season may also have been attributable to some early rain events. Nevertheless, the present study demonstrates that well-managed, productive tropical pastures can attain ecosystem gas exchange rates equivalent to fertilized C4 crops growing in the temperate zone. [source]

Do arthropod assemblages display globally consistent responses to intensified agricultural land use and management?

GLOBAL ECOLOGY, Issue 5 2008
S. J. Attwood
ABSTRACT Aim, To determine whether arthropod richness and abundance for combined taxa, feeding guilds and broad taxonomic groups respond in a globally consistent manner to a range of agricultural land-use and management intensification scenarios. Location, Mixed land-use agricultural landscapes, globally. Methods, We performed a series of meta-analyses using arthropod richness and abundance data derived from the published literature. Richness and abundance were compared among land uses that commonly occur in agricultural landscapes and that represent a gradient of increasing intensification. These included land-use comparisons, such as wooded native vegetation compared with improved pasture, and a management comparison, reduced-input cropping compared with conventional cropping. Data were analysed using three different meta-analytical techniques, including a simple vote counting method and a formal fixed-effects/random-effects meta-analysis. Results, Arthropod richness was significantly higher in areas of less intensive land use. The decline in arthropod richness was greater between native vegetation and agricultural land uses than among different agricultural land uses. These patterns were evident for all taxa combined, predators and decomposers, but not herbivorous taxa. Overall, arthropod abundance was greater in native vegetation than in agricultural lands and under reduced-input cropping compared with conventional cropping. Again, this trend was largely mirrored by predators and decomposers, but not herbivores. Main conclusions, The greater arthropod richness found in native vegetation relative to agricultural land types indicates that in production landscapes still containing considerable native vegetation, retention of that vegetation may well be the most effective method of conserving arthropod biodiversity. Conversely, in highly intensified agricultural landscapes with little remaining native vegetation, the employment of reduced-input crop management and the provision of relatively low-intensity agricultural land uses, such as pasture, may prove effective in maintaining arthropod diversity, and potentially in promoting functionally important groups such as predators and decomposers. [source]

Landscape modification and habitat fragmentation: a synthesis

GLOBAL ECOLOGY, Issue 3 2007
Joern Fischer
ABSTRACT Landscape modification and habitat fragmentation are key drivers of global species loss. Their effects may be understood by focusing on: (1) individual species and the processes threatening them, and (2) human-perceived landscape patterns and their correlation with species and assemblages. Individual species may decline as a result of interacting exogenous and endogenous threats, including habitat loss, habitat degradation, habitat isolation, changes in the biology, behaviour, and interactions of species, as well as additional, stochastic threats. Human-perceived landscape patterns that are frequently correlated with species assemblages include the amount and structure of native vegetation, the prevalence of anthropogenic edges, the degree of landscape connectivity, and the structure and heterogeneity of modified areas. Extinction cascades are particularly likely to occur in landscapes with low native vegetation cover, low landscape connectivity, degraded native vegetation and intensive land use in modified areas, especially if keystone species or entire functional groups of species are lost. This review (1) demonstrates that species-oriented and pattern-oriented approaches to understanding the ecology of modified landscapes are highly complementary, (2) clarifies the links between a wide range of interconnected themes, and (3) provides clear and consistent terminology. Tangible research and management priorities are outlined that are likely to benefit the conservation of native species in modified landscapes around the world. [source]

Salinization of a Fresh Palaeo-Ground Water Resource by Enhanced Recharge

GROUND WATER, Issue 1 2003
F.W. Leaney
Deterioration of fresh ground water resources caused by salinization is a growing issue in many arid and semi-arid parts of the world. We discuss here the incipient salinization of a 104 km2 area of fresh ground water (<3000 mg/L) in the semiarid Murray Basin of Australia caused by widespread changes in land use. Ground water 14C concentrations and unsaturated zone Cl soil water inventories indicate that the low salinity ground water originated mainly from palaeo-recharge during wet climatic periods more than 20,000 years ago. However, much of the soil water in the 20 to 60 m thick unsaturated zone throughout the area is generally saline (> 15,000 mg/L) because of relatively high evapotranspiration during the predominantly semiarid climate of the last 20,000 years. Widespread clearing of native vegetation over the last 100 years and replacement with crops and pastures leads to enhancement of recharge rates that progressively displace the saline soil-water from the unsaturated zone into the ground water. To quantify the impact of this new hydrologic regime, a one-dimensional model that simulates projected ground water salinities as a function of depth to ground water, recharge rates, and soil water salt inventory was developed. Results from the model suggest that, in some areas, the ground water salinity within the top 10 m of the water table is likely to increase by a factor of 2 to 6 during the next 100 years. Ground water quality will therefore potentially degrade beyond the point of usefulness well before extraction of the ground water exhausts the resource. [source]

Global perspective on hydrology, water balance, and water resources management in arid basins

HYDROLOGICAL PROCESSES, Issue 2 2010
Yanjun Shen
Abstract Arid and semiarid regions comprise a large part of the world's terrestrial area and are home to hundreds of millions of people. Water resources in arid regions are rare and critical to society and to ecosystems. The hydrologic cycle in arid and semiarid regions has been greatly altered due to long-term human exploitation. Under conditions of global warming, water resources in these regions are expected to be more unstable and ecosystems likely will suffer from severe water stress. In the current special issue contributed to understanding ecohydrologic processes and water-related problems in arid regions of western China, this paper provides a global perspective on the hydrology and water balance of six major arid basins of the world. A number of global datasets, including the state-of-the-art ensemble simulation of land surface models by GSWP2 (Global Soil Wetness Project II, a project by GEWEX), were used to address the water balance terms in the world's major hydroclimatic regions. The common characteristics of hydrologic cycles and water balance in arid basins are as follows: strong evapotranspiration characterizes the hydrological cycle in arid basins; and in water use sectors irrigation consumes a large amount of water, resulting in degradation of native vegetation. From the ecohydrology viewpoint, a comprehensive study of hydrological and ecological processes of water utilization in arid basins is urgently needed. Copyright © 2009 John Wiley & Sons, Ltd. [source]

Nests, vocalizations, and conservation status of endangered Cochabamba Mountain-Finches (Compsospiza garleppi)

JOURNAL OF FIELD ORNITHOLOGY, Issue 3 2009
Noemí Esther Huanca
ABSTRACT Cochabamba Mountain-Finches (Compsospiza garleppi) are endangered residents of semihumid shrublands in the high Andes, with a range restricted to a few high valleys surrounding the city of Cochabamba, Bolivia. We examined the breeding behavior, feeding ecology, habitat requirements, vocalizations, and conservation status of Cochabamba Mountain-Finches from November 2006 to April 2007. We observed 10 nests of eight pairs, with nests found in a variety of small woody shrubs as well as bunchgrass and a ground bromeliad. Clutches (N= 2) consisted of one or two eggs, and all broods (N= 4) included one or two young. Our observations suggest that Cochabamba Mountain-Finches are not Polylepis specialists as previously thought, and use a diversity of native shrubs often associated with Polylepis woodlands for foraging and nesting. Pairs inhabited modified habitats where native vegetation and woodland edge persisted, but were not observed in closed canopy woodlands. Cochabamba Mountain-Finches frequently foraged on the edges of potato fields in a rural community and, at least occasionally, consumed parts of unearthed tubers. We recorded two previously unknown song types and three types of calls, and one song type was found to be useful for playback surveys. We recommend that future research and conservation actions include thorough surveys using playback to determine population sizes, and that habitat restoration projects focus on maintaining a diversity of native shrubs rather than only Polylepis trees. SINOPSIS Compsospiza garleppi es una especie residente en peligro de las tierras arbustivas semihúmedas de los altos Andes, con un rango restringido a unos pocos valles en los alrededores de la ciudad de Cochabamba, Bolivia. Nosotros examinamos el comportamiento reproductivo, la ecología alimentaria, los requerimientos de hábitat, vocalizaciones y estado de conservación de Compsospiza garleppi desde Noviembre 2006 hasta Abril 2007. Observamos 10 nidos de ocho parejas, los nidos fueron encontrados en una variedad de pequeños arbustos al igual que en montones de pastos y bromelias de suelo. La nidadas (N= 2) consistieron de uno o dos huevos y uno o dos polluelos (N= 4). Nuestras observaciones sugieren que Compsospiza garleppi no es un especialista de Polylepis como se había pensado anteriormente, y usa una diversidad de arbustos nativos asociados con bosques de Polylepis para buscar alimento y anidar. Se encontraron parejas en hábitat modificado en donde la vegetación nativa y los bordes de bosque persistieron, pero no fueron observadas en bosques con un dosel cerrado. Compsospiza garlepp busco alimento frecuentemente en los bordes de plantaciones de papa en una comunidad rural y, ocasionalmente, consumió partes de tubérculos desenterrados. Nosotros grabamos dos cantos no descritos anteriormente y tres tipos de llamados, un tipo de los cantos fue beneficioso para estudios de playback. Nosotros recomendamos que futuros estudios y acciones de conservación usen playback como herramienta para realizar censos minuciosos para determinar tamaños poblacionales, y que proyectos de restauración de hábitat se enfoquen en el mantenimiento de la diversidad de arbustos nativos en vez de únicamente mantener árboles de Polylepis. [source]

Dispersal and phylogeography of the agamid lizard Amphibolurus nobbi in fragmented and continuous habitat

MOLECULAR ECOLOGY, Issue 6 2005
D. A. DRISCOLL
Abstract Approximately 90% of native vegetation has been cleared for agriculture in central New South Wales, Australia. Habitat loss has reduced and fragmented populations of the agamid lizard Amphibolurus nobbi. We compared genetic structure of populations of this species in an unmodified landscape with those from small nature reserves and linear remnants in farming areas. We ask: Is there evidence for reduced dispersal and population fragmentation among farm populations? Using 2008 bp mtDNA sequences and allozyme electrophoresis, we found that small populations in farming areas had as much genetic variation as populations in nature reserves. Application of nested clade analysis (NCA) indicated isolation-by-distance effects among populations from uncleared areas, but not among populations within farming locations. The genetic evidence therefore implied a high level of migration in the cleared landscapes. High dispersal after fragmentation may have resulted from either a burst of movement at the time of land clearing with dragons from many sources finding refuge in a few remnants, or from ongoing rapid dispersal through unsuitable habitat. A phylogeny based on mtDNA revealed that A. nobbi populations in the study area are deeply divided into two reciprocally monophyletic groups. Although we did not sample the entire species range, one of these evolutionarily significant units was only detected in remnant vegetation in the agricultural landscape. Therefore, a substantial subclade of this species may be vulnerable to extinction. Our findings emphasize that local populations of widespread species can harbour important intraspecific genetic diversity, supporting the case for maintaining widespread species throughout production landscapes. [source]

Genetic diversity in hazelnut (Corylus avellana L.) cultivars from Black Sea countries assessed using SSR markers

PLANT BREEDING, Issue 4 2010
K. Gürcan
With 6 figures and 6 tables Abstract European hazelnut (Corylus avellana L.) is an important crop in Turkey, Georgia and Azerbaijan, where cultivars were selected from the native vegetation. Accessions from Turkey have been assigned to the Black Sea group, and cultivars from Georgia and Azerbaijan have a similar phenotype. Genetic diversity was investigated in 88 accessions from these three countries and compared with cultivars from Spain and Italy using 12 microsatellite loci. A high level of genetic diversity (He = 0.71, Ho = 0.70) was observed in the Black Sea accessions. Six Turkish accessions in the US hazelnut collections were found to be synonyms of cultivars in the Turkish collection in Giresun. An unweighted pair-group method using arithmetic average dendrogram and principal component analysis of 109 unique accessions showed a tendency to form subgroups by country of origin, and high diversity within each subgroup. A moderate shift in allelic frequencies (FST = 0.114,0.131) was seen between accessions from the Black Sea and the Spanish-Italian accessions. Simple sequence repeat analysis identified the putative parents of two Turkish cultivars. [source]

Resilience of Native Plant Community Following Manual Control of Invasive Cinchona pubescens in Galápagos

RESTORATION ECOLOGY, Issue 2010
Heinke Jäger
As invasive plant species are a major driver of change on oceanic islands, their control is an important challenge for restoration ecology. The post-control recovery of native vegetation is crucial for the treatments to be considered successful, but few studies have evaluated the effects of control measures on both target and non-target species. To investigate the efficiency of manual control of Cinchona pubescens and its impacts on the sub-tropical highland vegetation of Santa Cruz Island, Galápagos, vegetation was sampled before and up to two years after control was carried out in permanent sampling plots. Manual control significantly reduced Cinchona density. Due to regeneration from the seed or bud bank, follow-up control is required, however, for long-term success. Despite heavy disturbance from tree uprooting, herbaceous angiosperms were little affected by the control actions, whereas dominant fern species declined in cover initially. Most native, endemic, and other introduced species regained their pre-control levels of cover 2 years after control; some species even exceeded them. The total number of species significantly increased over the study period, as did species diversity. The native highland vegetation appeared to be resilient, recovering to a level probably more characteristic of the pre-invasion state without human intervention after Cinchona control. However, some introduced species seemed to have been facilitated by the control actions, namely Stachys agraria and Rubus niveus. Further monitoring is needed to confirm the long-term nature of vegetation change in the area. [source]

Using Macrophytes in Urban Stream Rehabilitation: A Cautionary Tale

RESTORATION ECOLOGY, Issue 6 2009
Alastair M. Suren
Abstract Native macrophytes were transplanted into a small urban stream as part of a rehabilitation program, that also meandered the previously channeled stream, naturalized stream banks, and planted native riparian vegetation. Transplanted macrophytes minimized spread of introduced macrophytes and were viewed beneficially by residents, as was the stream rehabilitation. We transplanted the native macrophyte Myriophyllum triphyllum into five larger streams dominated by exotic macrophytes,some of which were weeded prior to transplanting,to see whether Myriophyllum could prevent regrowth of weeded plants. Transplanted Myriophyllum plants were washed away in two streams, reflecting high shear stresses there. Myriophyllum cover in the other streams decreased as weeded plants regrew. Our attempt at eliminating exotic macrophytes in patches in large streams was unsuccessful. Furthermore, council authorities weeded other experimental sections following complaints from residents of excess macrophyte growth. This problem highlighted conflicting multiple values placed on urban streams by managers and the public. A repeat survey of residents living near the original rehabilitated stream showed that many respondents were now critical of excessive plant growth,both in-stream and riparian. A recurring comment made concerned the apparent lack of maintenance to the stream, giving it an untidy appearance. Difficulties with propagating and transplanting native macrophytes into larger streams, coupled with a negative perception of native vegetation (both in-stream and riparian) if it looks unmanaged, suggest that planting macrophytes or riparian plants as part of urban stream rehabilitation programs may be more problematic than realized. [source]

Sustainable production of crops and pastures under drought in a Mediterranean environment

ANNALS OF APPLIED BIOLOGY, Issue 2 2004
NEIL C TURNER
Summary Mediterranean environments are characterised by cool wet winters and hot dry summers. While native vegetation in Mediterranean-climatic zones usually comprises a mixture of perennial and annual plants, agricultural development in the Mediterranean-climatic region of Australia has led to the clearing of the perennial vegetation and its replacement with annual crops and pastures. In the Mediterranean environments of southern Australia this has led to secondary (dryland) salinisation. In order to slow land degradation, perennial trees and pasture species are being reintroduced to increase the productivity of the saline areas. The annual crops and pastures that form the backbone of dryland farming systems in the Mediterranean-climatic zone of Australia are grown during the cool wet winter months on incoming rainfall and mature during spring and early summer as temperatures and rates of evaporation rise and rainfall decreases. Thus, crop and pasture growth is usually curtailed by terminal drought. Where available, supplementary irrigation in spring can lead to significant increases in yield and water use efficiency. In order to sustain production of annual crops in Mediterranean environments, both agronomic and genetic options have been employed. An analysis of the yield increases of wheat in Mediterranean-climatic regions shows that there has generally been an increase in the yields over the past decades, albeit at a lower rate than in more temperate regions. Approximately half of this increase can be attributed to agronomic improvements and half to genetic improvements. The agronomic improvements that have been utilised to sustain the increased yields include earlier planting to more closely match crop growth to rainfall distribution, use of fertilisers to increase early growth, minimum tillage to enable earlier planting and increase plant transpiration at the expense of soil evaporation, rotations to reduce weed control and disease incidence, and use of herbicides, insecticides and fungicides to reduce losses from weeds, insects and disease. Genetic improvements include changing the phenological development to better match the rainfall, increased early vigour, deeper rooting, osmotic adjustment, increased transpiration efficiency and improved assimilate storage and remobilisation. Mediterranean environments that are subjected annually to terminal drought can be both environmentally and economically sustainable, but to maximise plant water use efficiency while maintaining crop productivity requires an understanding of the interaction between genotypes, environment and management. [source]

Relationship between species richness and spatial and temporal distance from seed source in semi-natural grassland

APPLIED VEGETATION SCIENCE, Issue 3 2010
Toshikazu Matsumura
Abstract Question: How do traditional management practices of field margins maintain the biodiversity of native grassland species? Location: Semi-natural grassland on the field margins of traditional and consolidated agricultural fields on Awaji Island, central Japan. Methods: The distance to the nearest traditional field margin to the study sites was determined because the traditional field was considered as a seed source of native vegetation to the semi-natural grasslands under study. We selected field margins in consolidated fields of different ages and distances from seed sources. Indicator species for both field types were sought. Regression analysis and detrended correspondence analysis (DCA) were used to determine the effect of spatial and temporal distances on the species composition of native vegetation. Results: Species richness differed significantly between the margin of traditional and consolidated fields. We identified significant indicator species of traditional fields, but not of consolidated fields. In consolidated fields, species richness increased significantly with age and decreased significantly with increasing distance to the source. At younger sites, species richness decreased faster with distance to the source because of strong negative correlation, but not at older sites. DCA ordination plots similarly indicated that similarities of vegetation composition in consolidated and traditional fields decreased with distance, and the effect of distance decreased with age. Conclusions: The species composition of the grassland margins of consolidated field was more similar to the margins of traditional fields if the consolidated fields were older, and/or closer to traditional fields. This pattern suggests that dispersal may play a role in the establishment of species on field margins. [source]

Landscape-scale detection and mapping of invasive African Olive (Olea europaea L. ssp. cuspidata Wall ex G. Don Ciferri) in SW Sydney, Australia using satellite remote sensing

APPLIED VEGETATION SCIENCE, Issue 2 2009
P. Cuneo
Abstract Question: Is satellite imagery an effective tool for mapping and examining the distribution of the invasive species Olea europaea L. ssp. cuspidata at a regional landscape scale? Location: Southwest Sydney, Australia. Methods: Remote sensing software was used to classify pixels of Olea europaea L. ssp. cuspidata (African Olive) and major vegetation types from satellite imagery, using a "supervised classification" technique across a 721 km2 study area in the Cumberland Plain region of western Sydney. A map of African Olive distribution was produced from the image analysis and checked for accuracy at 337 random locations using ground observation and comparison with existing vegetation maps. The African Olive distribution data were then used in a GIS analysis with additional spatial datasets to investigate the relationship between the distribution of African Olive and environmental factors, and to quantify the conservation threat to endangered native vegetation. Results: A total area of 1907 ha of dense African Olive infestation was identified, with an omission error of 7.5% and a commission error of 5.4%. African Olive was found to occur on the steepest slopes (mean slope 14.3°) of the vegetation classes examined, with aspect analysis identifying a high prevalence on south- and southwest-facing slopes. The analysis also quantified the level of African Olive infestation in endangered ecological communities, with Western Sydney Dry Rainforest (25% affected) and Moist Shale Woodland (28% affected) identified as most vulnerable to African Olive invasion. Conclusion: The distribution of African Olive can be efficiently mapped at a landscape scale. This technique, used in association with additional spatial datasets, identified African Olive as a significant environmental weed in SW Sydney, occupying a greater area than previously recognised and threatening several endangered native vegetation communities. [source]

Grazing without grasses: Effects of introduced livestock on plant community composition in an arid environment in northern Patagonia

APPLIED VEGETATION SCIENCE, Issue 1 2006
Mariana Tadey
Abstract Question: How does grazing intensity affect plant density, cover and species richness in an Patagonian arid ecosystem? Location: Monte steppe ecoregion, SW Argentina. Methods: I analysed the effect of grazing on plant density, cover and species richness using a stocking rate gradient within the same habitat. Six paddocks were used with stocking rates ranging between 0.002 , 0.038 livestock/ha. Plant density, species richness, plant cover and percentage of grazed branches were determined by sampling plots within each paddock. The percentage of grazed branches was used as an independent measurement of grazing intensity. Results: Higher stocking rates were related to lower plant density, species richness and plant cover. The paddock with the lowest grazing intensity had 86% more plants per unit area, 63% more plant cover and 48% higher species richness. The percentage of grazed branches and the quantity of dung increased with stocking rate. Conclusions: Introduced livestock seriously affect native vegetation in the Patagonian Monte. The damage observed in this xerophytic plant community suggests that plant adaptations to aridity do not provide an advantage to tolerate or avoid grazing by vertebrate herbivores in this region. Plant degradation in this arid environment is comparable to the degradation found in more humid ecosystems. [source]

Application of QuickBird and aerial imagery to detect Pinus radiata in remnant vegetation

AUSTRAL ECOLOGY, Issue 6 2010
NERISSA HABY
Abstract The invasion of Pinus radiata from long-term established plantations is contributing to the degradation of fragmented and isolated remnants of native vegetation. Within the south-east of South Australia, the 20 vegetation communities that occur within 500 m of a plantation edge are at risk, including nine state threatened communities. To plan effective mitigation strategies, the current extent and distribution of P. radiata needs to be ascertained. High spatial resolution, multispectral QuickBird imagery and aerial photography were used to classify P. radiata within eucalypt and acacia woodlands, melaleuca shrubland, modified pasture and an Eucalyptus globulus plantation. Unsupervised classification of aerial photography gave the best result showing reasonable conformity with the observed distribution of P. radiata at the site scale. However, the 9.4 ± 13.5 (SD) cover classified in the quadrats sampled for the accuracy assessment exceeded the 1.4 ± 2.4 (SD) P. radiata cover determined from an independent dataset. Only 30.1 ± 37.9% (SD) of trees within the quadrats and 9.40 ± 13.49% (SD) of their foliage cover were classified. Trees detected by partial classification of canopy were positively correlated with both tree height and canopy diameter. Overall, the low detection rates were attributed to insufficient spectral resolution. Using higher resolution imagery, together with an object-based image analysis or combination of multispectral and airborne digital image classification, restricted to large emergent adult trees using LiDAR analysis, is likely to improve adult P. radiata detection accuracy. [source]

Monitoring the impact of climate change on biodiversity: The challenge of megadiverse Mediterranean climate ecosystems

AUSTRAL ECOLOGY, Issue 4 2010
IAN ABBOTT
Abstract The Mediterranean climate regions of Western Australia and South Africa are recognized as global hot spots of diversity. Both are threatened by climate changes that are projected to have significant impacts on the quantity and variability of rainfall and affect key ecosystem drivers (e.g. fire regimes). This poses significant challenges to monitoring programs designed to detect these impacts. Effective monitoring of the impact of climate change on biodiversity (rather than individual species) requires a cross-disciplinary, coordinated, focused and integrated approach. Ideally, this should involve a multidisciplinary team of specialists working to a common plan on the same set of plots. The contributions of ,citizen scientists' are potentially useful if well managed. Biodiversity per se (across all kingdoms of life, and including the levels of the gene, population and community) should be monitored, especially key species interactions and processes. Forestcheck is an example of such a program which has been applied in forests in south-west Western Australia since 2001. In concert with measuring the direct impact of climate change on biodiversity and the indirect impact of factors that affect biodiversity (such as disease, invasive species, fire regime and habitat removal), there is a need for a proactive focus on creating, maintaining and monitoring resilience to climate change impacts in ecosystems. It is also necessary to monitor the effectiveness of management actions such as vegetation thinning, changes in fire regimes, species translocations and revegetation of farmland to link isolated protected areas in agricultural landscapes, remnant native vegetation in rangelands and extensive protected areas. A pluralist approach is recommended. This should include natural experiments, matched photographs where available, passive adaptive management, active adaptive management and traditional reductionist scientific investigation. The resultant synthesis of information from this range of sources is likely to be a predictive, robust and credible record of historical change. [source]

Diversity and salt tolerance of native Acacia rhizobia isolated from saline and non-saline soils

AUSTRAL ECOLOGY, Issue 8 2009
PETER H. THRALL
Abstract Re-establishing native vegetation in stressed soils is of considerable importance in many parts of the world, leading to significant interest in using plant,soil symbiont interactions to increase the cost-effectiveness of large-scale restoration. However, effective use of soil microbes in revegetation requires knowledge of how microbe communities vary along environmental stress gradients, as well as how such variation relates to symbiont effectiveness. In Australia, shrubby legumes dominate many ecosystems where dryland salinity is a major issue, and improving plant establishment in saline soils is a priority of regional management agencies. In this study, strains of rhizobial bacteria were isolated from a range of Acacia spp. growing in saline and non-saline soils. Replicates of each strain were grown under several salinity levels in liquid culture and characterized for growth and salt tolerance. Genetic characterization of rhizobia showed considerable variation among strains, with salt tolerance and growth generally higher in rhizobial populations derived from more saline soils. These strains showed markedly different genetic profiles and generic affiliations to those from more temperate soils, suggesting community differentiation in relation to salt stress. The identification of novel genomic species from saline soils suggests that the diversity of rhizobia associated with Australian Acacia spp. is significantly greater than previously described. Overall, the ability of some symbiotically effective strains to tolerate high salinity is promising with regard to improving host plant re-establishment in these soils. [source]

Landscape structure influences tree density patterns in fragmented woodlands in semi-arid eastern Australia

AUSTRAL ECOLOGY, Issue 6 2009
VALERIE J. DEBUSE
Abstract Landscape and local-scale influences are important drivers of plant community structure. However, their relative contribution and the degree to which they interact remain unclear. We quantified the extent to which landscape structure, within-patch habitat and their confounding effects determine post-clearing tree densities and composition in agricultural landscapes in eastern subtropical Australia. Landscape structure (incorporating habitat fragmentation and loss) and within-patch (site) features were quantified for 60 remnant patches of Eucalyptus populnea (Myrtaceae) woodland. Tree density and species for three ecological maturity classes (regeneration, early maturity, late maturity) and local site features were assessed in one 100 × 10 m plot per patch. All but one landscape characteristic was determined within a 1.3-km radius of plots; Euclidean nearest neighbour distance was measured inside a 5-km radius. Variation in tree density and composition for each maturity class was partitioned into independent landscape, independent site and joint effects of landscape and site features using redundancy analysis. Independent site effects explained more variation in regeneration density and composition than pure landscape effects; significant predictors were the proportion of early and late maturity trees at a site, rainfall and the associated interaction. Conversely, landscape structure explained greater variation in early and late maturity tree density and composition than site predictors. Area of remnant native vegetation within a landscape and patch characteristics (area, shape, edge contrast) were significant predictors of early maturity tree density. However, 31% of the explained variation in early mature tree differences represented confounding influences of landscape and local variables. We suggest that within-patch characteristics are important in influencing semi-arid woodland tree regeneration. However, independent and confounding effects of landscape structure resulting from previous vegetation clearing may have exerted a greater historical influence on older cohorts and should be accounted for when examining woodland dynamics across a broader range of environments. [source]