Modelling the effect of El Niño on the persistence of small populations: The Galápagos penguin as a case study

Small populations are vulnerable to long-term declines, even where short-term censuses indicate increasing trends in numbers. Census data for the Galápagos penguin (Spheniscus mendiculus) collected between 1970 and 2004 provide evidence that despite year-to-year population increases detected in most of the annual censuses, the strong El Niño events of 1982-83 and 1997-98 were followed by population declines of more than 60% from which the species has yet to recover. Such large declines raise concerns about the future viability of the species because the frequency and severity of El Niño events are predicted to increase. We used the simulation software VORTEX to evaluate the potential effects of El Niño on the risk of extinction of the Galápagos penguin population and its four constituent subpopulations. Weak and strong El Niño events were treated as catastrophes, with varying frequencies, which simulated past, current and future effects on the penguin population. The “Current El Niño” scenario, based on the frequency of El Niño events recorded in the Galápagos between 1965 and 2004, indicated an approximately 30% probability of extinction within the next 100 years for the penguin population. More ominously, the species may be at a greater risk if the frequency of strong El Niño episodes increases only marginally. A probability of extinction greater than 80% was predicted when the current frequency (5%) of strong El Niño events was doubled (to 10%). The probabilities of extinctions were higher for each subpopulation treated individually, ranging from 34% for Isabela and Fernandina, 64% for Bartolomé-Santiago to 78% for the smallest subpopulation on Floreana. Sensitivity analyses identified survival of penguins during El Niño events and sex ratio as influential parameters. The estimates of extinction risk may be conservative as other threats associated with increased human activities on the islands may further compromise species persistence.     

The influence of paleofloods on archaeological settlement patterns during A.D. 1050–1170 along the Colorado River in the Grand Canyon,Arizona, USA

Excavations at four archaeological sites consisting of the material remains of A.D. 1050–1170 era farmers along the Colorado River in Grand Canyon National Park, yield geomorphic information used to address questions related to settlement patterns. Archaeological excavation units, test pits, feature fill, and natural exposures contain sediments used to interpret geomorphic history that can, in turn, shed light on archaeological site selection in a challenging environment. The Grand Canyon experiences dramatic geomorphic events such as catastrophic floods and destructive debris flows that are preserved in the stratigraphic record, and can be used to understand cultural/landscape interactions. By combining new geomorphic, stratigraphic, and archaeological data collected during recent excavations with results from previous geomorphic and sediment transport studies, observed trends can be interpreted regarding the possible influence of paleofloods on past settlement patterns. For example, at each of the four sites, reconstructed paleoflood elevations (from existing HEC-RAS virtual shorelines), flood recurrence intervals, site layout, and site stratigraphy/geomorphic setting suggests a temporal trend in site location. The two early sites (Early Pueblo II period: A.D. 1050–1080) contain habitation features located above the approximately 6–8 year high flood (3500 cubic meters per second [cms]) recurrence interval; larger floods (4800 to 5900 cms) of a longer recurrence interval between 40 and 80 years inundate these features. The two later sites in the sample (Late Pueblo II; A.D. 1080–1170) contain habitation features located well above the 40–80 year recurrence high flows. We suggest that early farmers (Early Pueblo II period: A.D. 1050–1080) may not have had adequate experience with flood magnitudes and frequencies and therefore their habitation structures were located in risk-prone areas relatively close to the river. Later habitations (Late Pueblo II; A.D. 1080–1170) were positioned in more protected areas further from the river, perhaps reflecting an acquired knowledge of river dynamics. These trends, although currently based on a limited data set, provide insights into site selection decisions and settlement patterns of early farmers along the Colorado River through Grand Canyon.     

Biological effects of El Niño on the Galápagos penguin

Long-term monitoring of physical and biological parameters is essential for understanding the effects of El Niño on bird populations, particularly for small or declining populations. We examined the biological effects of El Niño activity from 1965 to 2004 using instrumental sea-surface temperatures from the Galápagos Islands and 20 years of census counts of the Galápagos penguin. Between 1965 and 2004, nine El Niño events were recorded of which two were strong and seven were weak. The two strong El Niño events of 1982-1983 and 1997-1998 were followed by crashes of 77% and 65% of the penguin population, respectively. The evidence suggests that the increased frequency of weak El Niño events limits population recovery. The 2004 penguin population is estimated to be at less than 50% of that prior to the strong 1982-1983 El Niño event. We discuss the biological effects of increased El Niño intensity and frequency within the context of a 6000-year record of El Niño influence and in the light of increasing anthropogenic threats operating after 1535, when the Archipelago was discovered by Europeans.     

Evaluating effects of deforestation, hunting, and El Niño events on a threatened lemur

Madagascar ranks as one of the world’s top extinction hotspots because of its high endemism and high rate of habitat degradation. Global climate phenomena such as El Niño Southern Oscillations may have confounding impacts on the island’s threatened biota but these effects are less well known. We performed a demographic study of Propithecus edwardsi, a lemur inhabiting the eastern rainforest of Madagascar, to evaluate the impact of deforestation, hunting, and El Niño on its population and to re-evaluate present endangerment categorization under the IUCN. Over 18 years of demographic data, including survival and fecundity rates were used to parameterize a stochastic population model structured with three stage classes (yearlings, juveniles, and adults). Results demonstrate that hunting and deforestation are the most significant threats to the population. Analysis of several plausible scenarios and combinations of threat revealed that a 50% population decline within three generations was very likely, supporting current IUCN classification. However, the analysis also suggested that changing global cycles may pose further threat. The average fecundity of lemurs was over 65% lower during El Niño years. While not as severe as deforestation or hunting, if El Niño events remain at the current high frequency there may be negative consequences for the population. We suggest that it is most critical for this species continued survival to create more protected areas, not only to thwart hunting and deforestation, but also to give this endangered lemur a better chance to recover from and adapt to altered climate cycles in the future.     

The effect of some watershed,soil characteristics and morphometric factors on the relationship between the gully volume and length in Fars Province,Iran

A survey consisting of 146 first order gullies selected from five sites with different land use, soil and watershed properties was carried out to estimate the parameters of the empirical power function in order to describe the relationship between the gully volume and length in Fars province, Iran. Subsequently, the gullies were clustered into seven groups (“A” to “G”) based on nine morphometric factors. The linearized functions were fitted to the natural logarithms of the volume and length in each group and the parameters “a” and “b” were determined. The obtained “a” and “b” parameters are in the ranges of 1.0–10.8 and 0.8–1.4, respectively. Comparison of “a” and “b” parameters in each group with the mean of nine factors and the mean soil, watershed and land use characteristics in each group showed that the gully volume and average cross section are correlated with the gully depths in different sections and the gully head slopes. Also it was shown that the parameters of fitted functions to the plots of gully volumes versus gully lengths are proportional to width at the gully heads. The gully widths at the top and bottom of the five meter sections are correlated with the average upstream watershed area of the gullies.     

Linking cultural and environmental change in Peruvian prehistory: Geomorphological survey of the Samaca Basin, Lower Ica Valley, Peru

The lower Ica Valley on the hyperarid south coast of Peru is today largely depopulated and bereft of cultivation. Yet its extensive archaeological remains attest to substantial pre-Hispanic populations. We provide a case-study of Pre-Hispanic culturally induced environmental change through combining field archaeological and geomorphological survey with archaeobotanical, sedimentary and soil micromorphology approaches. Our investigations reveal that, although major El Niño climatic perturbations occurring around the end of the Early Intermediate Period are part of the explanation, more gradual, human-induced reduction in riparian dry-forest vegetation also lie behind major landscape change, which culminated during the Middle Horizon.     

Effective population size in a bottlenecked fur seal population

The census population size (N) is usually the only information available for most threatened species. For evolutionary matters, the effective population size (N_e), not the census number, is a prime concern. Factors such as variation in the sex ratio of breeding individuals, variation of population size in different generations and mating system are important. The South American fur seal, Arctocephalus australis, has been exploited in Peru by humans since ca. 2000 BC and now the original population declined 72%, as a result of low food availability during the severe El Niño in 1997-1998. In this sense A. australis is now classified as in danger of extinction in Peru. We present the first estimate of N_e of the Peruvian population of A. australis that takes into account the effects of mating system and variation in population size caused by the 1997-1998 El Niño. The resulting N_e was 2153 specimens. We believe that the estimated N_e for the Peruvian population is a critical value, because it is significantly lower than the mean minimum viable population for vertebrates (7000 breeding age adults). This estimated N_e is of critical importance because combined with the current El Niño events are reasons of great concern for the survival of the species and should be taken into account in future management plans to ensure the conservation and protection of the species in the Peruvian coast.     

A Neolithic yew bow in the Polish Carpathians: Evidence of the impact of human activity on mountainous palaeoenvironment from the Kamiennik landslide peat bog

A unique artefact — the fragment of a bow made of yew wood, indicating the hunting activity of prehistoric man — was found within the sediments of the landslide peat bog (at the depth of 330 cm) formed on the Mt. Kamiennik (Polish Flysch Carpathians). The datings of this artefact using ¹⁴C method at ca 3790–3380 cal BC indicate its connection with the activity of the Neolithic man, related to the Funnel Beaker Culture. In the sequence of the peat bog deposits formed since the Atlantic Phase, the palaeoclimatic changes of the Middle- and Late Holocene, as well as traces of human impact in these and subsequent periods were recorded and analysed using palynological, macrofossils, lithological methods, and dated with radiocarbon. Palaeoenvironmental changes identified in the peat horizon bearing the artefact were marked by the delivery of minerogenic, “high energy” deposits (with charcoal) to the peat bog, as well as distinct changes of plant communities. These phenomena confirm a significant human impact caused by the Prehistoric man on landslide areas. On the other hand, the study confirms significant importance of climatic condition for human activity and proves that landslide peat bog deposits are very sensitive records of palaeoenvironmental changes. The archaeological artefact essentially supplements the results of our interdisciplinary palaeoenvironmental study. It is one of the rare Neolithic bows found in the area of Europe, till now.     

Phosphorus content in five representative landscape units of the Lomas de Arequipa (Atacama Desert-Peru)

Phosphorus forms and content were studied in soils of the Lomas de Arequipa (Atacama desert, Peru) using a fractionation method. These Lomas are small hills periodically submitted to the El Niño-Southern Oscillation (ENSO) which causes heavy rainfall. Sample soils were randomly selected in five landscape types characterized by vegetation: cactaceae (Cac), cactaceae and herbaceous (CacHerb), shrubs (Shr), trees with cover < 60% (Tree) and shrubs or trees with cover > 60%) (ShrTree). All the soils were strongly acidic and classified as loamy sand, sandy loam or silt loam. Organic carbon content was under 1% in Cac or CacHerb, then increased strongly in ShrTree (6.50%). Considering phosphorus, all the forms (labile as well resistant forms) increased markedly from Cac soils to ShrTree soils. In all the soils, the labile forms (Resin-P: range 45–105 μg g^− 1; NaHCO3-Pi: 23–123 μg g^− 1; or NaHCO3-Po: 10–122 μg g^− 1) were very high. These high phosphorus contents were attributed to the specific climatic conditions of the Lomas that feature a long period of vegetation dormancy (very dry period) and a short period of growth, following ENSO-associated precipitation. We suggested that during the dry period, plant decay and microbial cells death lead to release and accumulation of labile P in the soil, the rainfall wetting the soil, permitting vegetation growth. In this respect, the Lomas climatic conditions contribute to soil fertility, especially as labile forms of phosphorus are chiefly concerned.     

Surprisingly small increase of the sedimentation rate in the floodplain of Morava River in the Strážnice area,Czech Republic,in the last 1300 years

Sediment profiles from the floodplain of Morava River in the Czech Republic have been collected from exposed river banks (4–6 m long sections) and cores (2–4 m deep) and investigated using a set of geochemical proxies validated by granulometry and conventional geochemical analysis, outlined in our previous paper. The work was conducted to evaluate the increase in sedimentation rate during Medieval and modern time periods. Correlation of sediments along the current channel belt allows identification of two most important synchronous changes in the channel structure over the past 1300 years: in the 13th century and at the end of the 16th century. These changes could be related to central European climatic extremes rather than to land cover/land use practises. Analysis of the pollen record in peaty deposits at the floodplain edge allows excluded dramatic deforestation in Medieval times. Maps of the area from the last five centuries revealed direct and indirect signs of past avulsions and clearly show how the original multichannel system was transformed into a single meandering channel in the early 20th century. The extrapolated aggradation rate (net vertical accretion of floodplain fines except for levee sediments) increased from 0.2–0.3 cm/year in 700 AD to 0.3–0.4 cm/year in 2000 AD depending on the grain size of the sediment. This is the smallest yet reported enhancement of siliclastic deposition, although Morava River watershed has been intensively used for agriculture and its land cover has changed in a manner similar to west and central European rivers.     

Irrigation agriculture and the sedimentary record in the Palpa Valley,southern Peru

Irrigation agriculture is an ancient and widespread feature in regions where allogenic rivers flow through arid landscapes. This paper reports the results of sedimentological–pedological investigations in the Palpa Valley in the coastal desert of southern Peru where sediment-laden river water is used for irrigation. An adapted facies classification is used to deduce a generalised stratigraphical sequence of the valley bottom sediments. Chronological constraints from radiocarbon dating and archaeological finds are used to reconstruct sedimentation rates for fossil to recent irragric anthrosols. Actualistic case studies are used to quantify present-day irrigation sedimentation. The investigations result in a clarification of the sedimentological and geomorphic history of this valley and a quantification of irrigation-related sedimentation. Irragric anthrosols date back more than 3500 years and provide direct evidence for the beginning of irrigation agriculture in this region. It is concluded that: (i) the up to approximately 4 m thick fine-grained sediments in the Palpa Valley bottom totaling a volume of 21.4 Mio. m³ are a result of long-lasting human impact and have to be considered as artefacts of prehistoric and historic irrigation agriculture in the hyperarid coastal desert; (ii) the fine-grained sediments represent a geoarchive which holds information on the history of irrigation agriculture as well as information on possible natural disturbance by extreme fluvial events; (iii) the identification of irragric anthrosols has implications for archaeological and paleoenvironmental reconstructions.     

Plant communities and soil phytolith assemblages relationship in native grasslands from southeastern Buenos Aires province,Argentina

This study has compared the phytolith production and soil phytolith assemblages of two native grass communities typical in Argentina, namely the monospecific Paspalum quadrifarium community or “pajonal”, and the Stipa-Piptochaetium community or “flechillar”. Five sites – three of which had been unmanaged while other two had been submitted to fire and fire-grazing management activities – were selected for study. The results show that in these sites a) phytolith production of the plant communities differed due to their diverse floristic composition, b) it was possible to define the type of management or the type of community based on soil phytolith assemblages, c) there were differences between plant communities and soil phytolith assemblages. These results suggest that modern phytolith assemblages are composed not only of local and present vegetation but also of extralocal/regional and probably past vegetation. Hypotheses about the probable processes involved in phytolith incorporation to soil have emerged during the investigation.     

ENSO classification indices and summer crop yields in the Southeastern USA

This research uses a quantitative methodology for directly comparing the responses of observed crop yields in the SE USA to ENSO phenomena classified using dissimilar ENSO indices. ENSO condition has been related to agricultural yields in many parts of the world. It has been generally recognized that the strongest effects on spring and summer crops occur during the boreal winter, and therefore most directly affect spring-summer field crops in the southern hemisphere. However, some ENSO effects on northern hemisphere spring and summer crops have been found, particularly when researchers have used sub-annual indicators of ENSO conditions that, unlike annual ENSO indices, distinguish between continuity and change prior to or during the crop season. To evaluate the utility of such sub-annual ENSO indicators for agriculture in the SE USA, a tercile-based scoring system was devised to compare four distinct ENSO indices: three monthly ENSO indices and the JMA annual ENSO index. Each index was scored in its ability to predict crop yields differing from the historically normal tercile for corn (Zea mays L.), cotton (Gossypiumhirsutum L.), and peanut (Arachis hypogaea L.). Annual crop yield data were used from selected counties in five Southeastern USA states. No geographic differentiation among the data was included in the analysis. This aggregation of county data increased the sample size for each crop, to address the limitation of a short time-series (47 years) distributed among up to 9 ENSO categories. Statistical significance was compared using contingency tables and the Fisher exact test. Peanut and corn yield response matched best to the Multivariate ENSO Index (MEI) and cotton, to the Oceanic Niño Index (ONI). The MEI and ONI are quantitative indices, while the lower-scoring JMA and Modified-JMA indices are categorical. Therefore, future efforts may reduce the focus on categorical (Niño, Niña, Neutral) classification, and explore the response of crop yields to quantitative ENSO data.     

Assessing the impact of fisheries, climate and disease on the dynamics of the Indian yellow-nosed Albatross

Many seabird populations are currently decreasing, especially albatrosses for which the primary threat is recognised to be mortality in fisheries. Introduced predators, climate change and other factors such as diseases can also have large impacts on seabirds. Here, we assessed the relative effect of three potential threats: climate, fisheries and diseases on the demography of an endangered marine predator and modelled its population dynamics to project its size under different scenarios. We based our study on a long-term monitoring of a colony of individually marked Indian yellow-nosed albatrosses at Amsterdam Island, subtropical Indian Ocean, that has declined during the past twenty years. We found no evidence for an impact of legal tuna longlining on demographic parameters. Hatching success was lower during El Niño years but survival (0.902 ± 0.011) was not affected by climatic factors. Avian cholera caused high chick mortality (0.808 ± 0.181) which in turn probably triggered the high emigration rate (0.038 ± 0.011) through dispersal of failed breeders. This colony has a high risk of extinction. However, the rest of the population at Amsterdam Island seemingly not affected to the same extent, declined but stabilised since 1998. Matrix models indicated that lowered adult survival and the very low breeding success, resulting in low recruitment, have both contributed to the decline of the yellow-nosed albatross colony until the mid-1990s, but that more recent decline was primarily caused by low fledging success. Our results highlight that potential threats such as fisheries, diseases or climate have to be considered simultaneously to disentangle their roles when assessing the conservation status of a marine predator species.     

Holocene paleosols and colluvial sediments in Northeast Tibet (Qinghai Province,China): Properties,dating and paleoenvironmental implications

Colluvial deposits consisting of silts and loams were detected in several climatologically different areas of NE Tibet (3200–3700 m a.s.l.). Layering, distinct organic content and low content of coarse matter as well as location in the relief revealed an origin from low-energy slope erosion (hillwash). Underlying and intercalated paleosols were classified as Chernozems, Phaeozems, Regosols and Fluvisols. Fifteen radiocarbon datings predominant on charcoal from both colluvial layers and paleosols yielded ages between 8988 ± 66 and 3512 ± 56 uncal BP. Natural or anthropogenic factors could have been the triggers of the erosional processes derived. It remains unclear which reason was mainly responsible, due to controversial paleoclimatic and geomorphic records as well as insufficient archaeological knowledge from this region. Determinations of charcoal and fossil wood revealed the Holocene occurrence of tree species (spruce, juniper) for areas which nowadays have no trees or only few forest islands. Thus large areas of NE Tibet which are at present steppes and alpine pastures were forested in the past.     

Factors controlling suspended sediment yield during runoff events in small headwater catchments of the Basque Country

For the first time in the Basque Country, turbidity (NTU), discharge (l/s) and precipitation (mm) have been continuously monitored in the gauging stations located at the outlet of three catchments (Aixola, Barrendiola and Añarbe) since October 2003. In this study, several data sets derived from flood events were used to develop turbidity and suspended sediment relationships for the three catchments separately, and so to estimate continuous suspended sediment concentration (SSC). Linear relationships are found in Barrendiola and Añarbe, and two curvilinear relationships for Aixola owing to changing sediment sources in the catchment. Several event (discharge, precipitation and suspended sediment concentration) and pre-event (discharge and precipitation) factors are calculated for all the events registered. With them correlation matrixes were developed for each catchment. Although some differences are found between catchments good correlation between precipitation (P), discharge (Q) and suspended sediment (SS) variables is found in general. Pre-event conditions are also well correlated with Q and SS variables in Barrendiola (higher regulation capacity) and Añarbe (larger area) but not in Aixola (“flash floods”). SSC-discharge evolutions through the events were also analysed. For Aixola four different types of hysteretic loops were observed: single lined, clockwise, counter-clockwise and eight-shaped; while for Barrendiola and Añarbe just clockwise loops were observed.     

Changes in a remnant of salmon gum Eucalyptus salmonophloia and York gum E. loxophleba woodland, 1978 to 1997. Implications for woodland conservation in the wheat-sheep regions of Australia

The condition of salmon gums Eucalyptus salmonophloia with large hollows in them in a 15-ha patch of remnant salmon gum-York gum E. loxophleba woodland in the northern wheatbelt of Western Australia was examined in 1978. The patch was an important breeding area for six species of cockatoo, including two endangered species. The patch was revisited in 1981 when the condition of all 682 salmon gums and York gums in the patch was examined and each was measured and photographed. A further visit was made in 1997 when the condition of the surviving trees was examined and each was again measured and photographed. The condition of the trees at each visit was classified as “good”, “staghorn”, “broken top”, “dead” or “fallen.” Over the period of the study there was a serious decline in the condition of the trees, with few large trees in the “good” category by 1997. The decline was particularly marked between 1978 and 1981 after a period of well-below average annual rainfall. Using data based on the rate of decline over the period 1978-1997, predictions were made of the fate of the trees in the patch. By 2125 only 46 (11% of the 1981 total) salmon gums were predicted to be alive with only one in the “good” category. Only 16 (17%) York gums were predicted to be alive by 2125, with only one in the “good” category. There was no evidence of any regeneration of woodland trees since 1929 when the patch was isolated by clearing for agriculture, and domestic livestock allowed to graze the patch. This deterioration of the dominant trees in the patch is symptomatic of remnant native vegetation over vast areas of Australia's extensively cleared wheat-sheep regions. The future of woodland patches like the one studied is bleak, as is the future of animals dependent on them for food, breeding sites and shelter. Active management, including fencing to exclude domestic livestock and measures to encourage regeneration of native plant communities, is necessary to counter the present regime of benign neglect that characterises most of Australia's management of native vegetation in agricultural landscapes.     

History, origin and extent of soil erosion on Easter Island (Rapa Nui)

The isolated Easter Island (Rapa Nui) is an outstanding example of land degradation caused by land use in a sensitive ecosystem. The focus of the investigation was placed on Poike peninsula, the most eastern part of Rapa Nui. While Poike peninsula was once supplied with fertile soils, in large areas desertification takes place today. Detailed analysis of soil profiles allowed the reconstruction of the history and of causes and effects of soil erosion and gullying in the context of land use history and cultural evolution. The results of the stratigraphic analysis prove that from the beginning of human settlement around AD 300/600 until AD 1280 the agriculture on Poike peninsula was characterised by sustainable land use and a traditional type of agro-forestry. Soil erosion was not significant. At around AD 1280 the woodland on Poike, dominated by the endemic palm Jubaea sp., was cleared by slashing and burning. Intensive farming on the upper slopes of the volcanic peninsula resulted in sheet erosion lasting until the 20th century. Settlements and ceremonial places which were built around AD 1300 on downslope areas were buried soon by sediments. Agriculture ceased around AD 1400 on downslope areas as the fertile soils were completely eroded. From AD 1400 until the late 19th century sheet erosion and the accumulation of fine-layered sediments migrated upslope. On average 8.6 Mg of soil per hectare and per year were reworked by erosion (eroded and accumulated within the catchment). Gullying began on Rapa Nui with the sudden increase in the number of sheep during the early 20th century. Gullies are still developing on the island and their ongoing enlargement created extended badlands on Poike which pose a significant problem for ecological and archaeological conservation strategies. Gullying rates exceed 190 Mg ha^{− 1} y^{− 1}.     

The decline of native Pacific island faunas: changes in status of the land snails of Samoa through the 20th century

The highly diverse and endemic Pacific island biota is disappearing and being replaced by a relatively small number of widespread alien species. The land snail fauna of Samoa (formerly Western Samoa) contains at least 72 species (58 native, 10 alien, four cryptogenic—of unknown origin). In 1992-1994 we surveyed the fauna in order to evaluate its status and, by comparison with previous surveys, to detect any trends. Twelve species have declined (eight native, two cryptogenic); 17 (15 native, two cryptogenic) show a “probable decline” or “possible decline”; five (four alien, one native) have increased or possibly increased. Some species showed no clear trend; others could not be evaluated, but some of them may be extinct. The fauna faces threats similar to those faced elsewhere, primarily habitat destruction and alien species impacts. Most notable is the introduction of a predatory flatworm, Platydemus manokwari, in attempts to control the giant African snail, Achatina fulica, which became established in Samoa in the 1990s. The flatworm may or may not be able to control A. fulica but poses a serious threat to the native snail fauna. Further introduction and distribution of alien predators should be strongly discouraged.     

Dispersal and establishment of floodplain grassland species as limiting factors in restoration

The restoration of grassland and its dependence on the dispersal of characteristic plant species was analysed in the Saale River floodplain near Halle (Germany). Species composition and soil nutrient content were investigated in grassland converted to extensive management in 1989 (“restoration grassland”) and in adjacent grassland that had never been managed intensively (“old grassland”). In two experiments dispersal of Silaum silaus and Serratula tinctoria was studied following introduction of these species into “restoration grassland”. Seedling establishment was recorded and compared with the “old grassland”. Ten years after conversion to extensive management, characteristic floodplain grassland species had only reappeared in locations very close to “old grassland”. There were still differences in soil nutrient content of both grassland sites but a comparison of seedling survival provided evidence that conditions of establishment were similar. However, establishment rates appeared to be low in both grassland types indicating that a large initial input of seeds is required for re-establishment. Seeds of Silaum silaus and Serratula tinctoria were dispersed very short distances. About 75% of the seedlings were found within 1.5 m of parent plants. Management and flooding did not increase dispersal distances. The results strongly suggest that poor dispersal was the main limiting factor in determining the success of restoration. The implications of this result for nature conservation are discussed.