Catastrophic Disturbance Research Articles

Recovery of species diversity after disturbance of broad-leaved Korean pine mixed forest in Changbai Mountain

Recovery of species diversity after catastrophic disturbance was influenced by a few factors, such as intensity of disturbance, availability of propagules, and the environmental conditions. In this paper, we examined pattems of species development after nearly 60a succession in burned broad-leaved Korean pine mixed forest on northem slope of Changbai Mountain. We assessed the recovery of plant species diversity in 3 types of forests under the condition with gradient of soil moisture. Results revealed that recovery of plant species diversity varied greatly under different environmental conditions. Species richness of secondary forests greatly related to the site condition. Secondary birch forest on mesic site had the greatest number of plant species and the following was poplar-birch forest and larch-birch forest. Most of characteristic taxa could be found in birch forest after 60a succession. For larch-birch forest on hydra site, most of climax species were still not able to invade, so it had the lowest species diversity.

Impact of a catastrophic hurricane on island populations

Lizard and spider populations were censused immediately before and after Hurricane Lili on islands differentially affected by the storm surge. The results support three general propositions. First, the larger organisms, lizards, are more resistant to the immediate impact of moderate disturbance, whereas the more prolific spiders recover faster. Second, extinction risk is related to population size when disturbance is moderate but not when it is catastrophic. Third, after catastrophic disturbance, the recovery rate among different types of organisms is related to dispersal ability. The absence of the poorer dispersers, lizards, from many suitable islands is probably the result of long-lasting effects of catastrophes.

SEASONAL CYCLE AND POPULATION DYNAMICS OF THE SEA HARE APLYSIA OCULIFERA IN THE NORTHERN GULF OF EILAT (AQABA), RED SEA

Populations of the sea hare, Aplysia oculifera (Adams & Reeve, 1850) (Gastropoda; Opisthobranchia), were studied in the northern coast of the Gulf of Eilat (Aqaba) between April 1988 and March 1992. Recruitment occurred from December to February, synchronized with the blooming of green algae (Enteromorpha intestinalis and Ulva sp.). A single recruitment event occurred each year, while a secondary recruitment was rarely, observed and was related to acute catastrophic disturbance of the habitat. Adult sea hares inhabited the inter- and subtidal zones from December—January to AprilJune, feeding on E. intestinalis and Ulva sp. Populations disappeared in April-June which coincided with disappearance of these green algae. Mean maximum body live mass of adult sea hares (MMBLM, that is the highest mean body mass recorded at specific site within the season) ranged from 0.77 to 33 g MMBLM, varied significantly among populations inhabiting the various study sites, and was significantly and inversely correlated with water movement intensity. Abundance of sea hares varied among sites and among years and was related to the amount of green algae during the recruitment season.

Nonequilibrium Dynamics between Catastrophic Disturbances and Old‐Growth Forests in Ponderosa Pine Landscapes of the Black Hills

An emerging goal of ecosystem management is to maintain ecosystems within their range of natural variability, which requires attention to pre‐EuroAmerican landscape‐scale processes and corresponding landscape structures (e.g., old‐growth forest distribution). The prevailing “equilibrium” view of ponderosa pine forest landscapes, for example, holds that frequent, low‐intensity surface fires maintained open, park‐like forests of large, old trees. Yet a contrasting “nonequilibrium” view suggests that some forest ecosystems are subject to unpredictable catastrophic disturbances that dramatically alter these ecosystems. To assess these views’ relevance, we examined early historical accounts and records of natural disturbances in the ponderosa pine forests of the Black Hills in South Dakota and Wyoming ( U.S.A.). There is evidence of frequent, low‐intensity surface fires and large, catastrophic disturbances before EuroAmerican influence. Several large, stand‐replacing fires occurred between 1730 and 1852, and, shortly after EuroAmerican settlement, a major outbreak of mountain pine beetles ( Dendroctonus ponderosae Hopk.) occurred. The location of these severe disturbances coincides geographically with early explorers’ reports of extensive tracts of relatively dense closed‐canopy forests, including some very large patches (5000+ ha) of dense old growth. This contrasts with sparse, open‐canopy forests thought to be maintained by periodic, low‐intensity surface fires. We suggest that the cooler, moister, central and northern Black Hills and topographically protected areas may have been dominated by infrequent, catastrophic disturbances that maintained large patches of dense forests, including large, contiguous patches of old growth, in a relative state of nonequilibrium. The warmer and drier southern Black Hills, south‐facing slopes, and exposed areas may have been dominated by frequent, low‐intensity surface fires and other small disturbances that maintained open‐canopy forests in a relative state of equilibrium. Proposed Black Hills National Forest management plans that exclusively endorse the equilibrium view are misdirected and will move the forest ecosystem farther outside its range of natural variability.Desequilibrio Dinámico entre Perturbaciones Catastróficas y Bosques Maduros en Paisajes de Pino Ponderosa de Black HillsUna meta del manejo de ecosistemas es mantenerlos dentro de su rango de variabilidad natural, lo cual requiere de considerar procesos pre‐euroamericanos a escala de paisaje y las correspondientes estructuras del paisaje (e.g., distribución de bosques maduros). Por ejemplo, la visión prevaleciente del “equilibrio” de paisajes de bosque de pino ponderosa sostiene que frecuentes fuegos superficiales de baja intensidad mantenían bosques “similares a parques” abiertos con árboles grandes y viejos. Pero, una contrastante visión de “desequilibrio” sugiere que algunos ecosistemas de bosque están sujetos a perturbaciones catastróficas impredecibles que los altera dramáticamente. Para evaluar la pertinencia de estas visiones examinamos informes históricos tempranos y registros de perturbaciones naturales en los bosques de pino ponderosa de Black Hills en Dakota del Sur y Wyoming (E.U.A.). Hay evidencia de frecuentes fuegos superficiales de baja intensidad y grandes perturbaciones catastróficas anteriores a la influencia euroamericana. Entre 1730 y 1852 ocurrieron varios incendios mayores y, poco después de la colonización euroamericana, el escarabajo de pino de montaña ( Dendroctonus ponderosae Hopk.) causó grandes daños. La localización de estas perturbaciones severas coincide geográficamente con los reportes de exploradores respecto a extensas zonas de bosques de dosel cerrado relativamente densos, incluyendo unas extensiones muy grandes (5000+ha) de bosque maduro denso. Esto contrasta con los bosques de dosel abierto dispersos que se pensaba eran mantenidos por los incendios de baja intensidad periódicos. Sugerimos que, por su mayor frescura y humedad, las Black Hills centrales y del norte y las áreas topográficamente protegidas pudieron haber sido dominadas por perturbaciones catastróficas infrecuentes que mantenían grandes extensiones de bosques densos, incluyendo grandes parches contiguos de bosque maduro, en un relativo estado de desequilibrio. Las Black Hills del sur y las laderas del sur, más cálidas y secas, pudieron haber sido dominadas por incendios de baja intensidad frecuentes y otras perturbaciones pequeñas que mantenían bosques de dosel abierto en un relativo estado de equilibrio. Los planes de manejo propuestos para el Bosque Nacional Black Hills que exclusivamente avalan la visión de equilibrio están mal orientados y llevarán al ecosistema del bosque más allá de su rango de variabilidad natural.

Succession dynamics in a maritime forest following Hurricane Hugo and fuel reduction burns

In 1989, Hurricane Hugo devastated the maritime forest communities on Bull Island, SC, where a system of permanent plots was established. This catastrophic disturbance and subsequent fires provided an opportunity to study secondary succession following interacting disturbances. This study quantifies the effects of the disturbances on woody vegetation and investigates potential long-term community change using TWINSPAN. Overstory live oak ( Quercus virginiana Miller) remained relatively intact, whereas old-growth loblolly pines ( Pinus taeda L.) and stands of the exotic tallow tree ( Sapium sebiferum (L.) Roxb.) were destroyed. Aggressive recruitment by S. sebiferum, unfavorable conditions for loblolly growth, and broad changes in sapling community composition indicate that successional trajectories in some sites may have been changed by severe disturbances.

Stand Structure and the Regeneration of Chamaecyparis pisifera (Sieb. et Zucc.) Endl. on Sites with Different Soil Development in an Old-growth Coniferous Forest, Central Japan

Stand structure and the regeneration of Chamaecyparis pisifera on sites with and without well-developed soil in an old-growth coniferous forest, Akasawa Forest Reserve, central Japan, were investigated, along with their relationships to other important coniferous species. Of stems of C. pisifera ≥5 cm diameter at breast height, stems with intermediate size were absent in stands on the developed-soil site, while those with smaller size increased in stands on the undeveloped-soil site, which supported a higher density of C. pisifera. In the stands without recent tree-fall of canopy stems on the developed-soil site, canopy stems of C. pisifera were distributed uniformly and the understory stems, patchily. On the other hand, both canopy and understory stems of C. pisifera in stands on the undeveloped-soil site were distributed patchily. In the understory, C. pisifera occurred as clonal patches formed by vegetative reproduction on various types of microsites including bare rocks. However, the clonal patches did not occur in a stand on the developed-soil site with dense saplings of an evergreen conifer, Thujopsis dolabrata, which can expand vegetatively with a well developed soil layer. Gap formation may induce C. pisifera to develop tree-form stems from shrubby clonal patches. On developed-soil sites, C. pisifera stands that survive a long disturbance-free period on this site need catastrophic disturbance for their regeneration, which will eliminate T. dolabrata in the understory and create bare soil for colonization of C. pisifera from seeds. On undeveloped-soil sites, C. pisifera replaces itself continuously by effective vegetative reproduction. Ground instability and the wet condition of this site may promote the replacement.

Hurricane disturbance and the regeneration of Lysiloma latisiliquum (Fabaceae): a tropical tree in south Florida

Large-scale catastrophic disturbances such as hurricanes may be critical events for the regeneration of late secondary canopy tree species. The impact of Hurricane Andrew, a severe Category 4 hurricane, on the tropical tree Lysiloma latisiliquum was examined in three south Florida subtropical forests along a gradient of hurricane disturbance (high, moderate, none). The population closest to the northern eye wall of the hurricane had the highest mortality and most severe structural damage while the population near the southern eye wall of the hurricane experienced less mortality and damage. Posthurricane reproduction was least in the disturbed sites while the undisturbed site had extensive reproduction in both 1993 and 1994. Average seed production was low due to seed predation by a bruchid beetle but some populations experienced spatial and temporal escape from this seed predator. Germination from a dormant seed bank occurred only at the most severely disturbed site in 1992. Seed germination was associated with both tip-up pits and high understory light levels. In experimental trials, fluctuating heat treatments for 5 days increased seed germination. Severe hurricane disturbance is believed to have triggered germination from a dormant seed bank through strong diurnal soil temperature fluctuations resulting from extensive canopy removal. In south Florida, the temporal and spatial dynamics of both hurricane and fire disturbance are predicted jointly to influence the population dynamics of this canopy tree species.

Modelling of underwater seismic centres and the generation and transformation of tsunami waves in seismic areas

The mechanism of underwater earthquakes and tsunami wave generation in the Azov Sea-Black Sea region is studied, and theoretical principles of selecting simulation models are elaborated. In this connection, the geophysical data on the distribution, intensity and mechanisms of underwater seismic zones that may give rise to catastrophic disturbances of the marine environment are summarized and categorized, specifically, those that give rise to tsunamis. This makes possible the development and updating of mathematical models for the generation of seismic and surface gravity waves, considering geological heterogeneities, bottom irregularities, bottom sediments, etc.

Effects of Hurricane Disturbance on Groundwater Chemistry and Riparian Function in a Tropical Rain Forest

The long-term response of shallow groundwater chemistry to the canopy disturbance and defoliation associated with Hurricane Hugo was studied at two sites in the Luquillo Experimental Forest, Puerto Rico. The sites differed in bedrock type, dominant vegetation, and availability of pre-hurricane data. At the primary study site, the Bisley catchment, hurricane disturbance resulted in increased concentrations of NO3-, NH4 , dissolved organic N, base cations, Cl-, and SiO2 in groundwater within 5 mo of the hurricane. The largest relative change in concentration occurred for K+, which increased from 0.7 to as high as 13 mg/L; concentrations were still 1.3 mg/L 5.5 yr after the hurricane. Most other solutes had returned to background levels within 1-2 yr of the hurricane. At the secondary study site, the Icacos catchment, N03- concentrations peaked at 1.1 mg/L one yr after the hurricane and decreased to nearly zero 5.5 yr after the hurricane. At both sites, N03- concentrations were higher in upslope wells than in those closer to the stream. Overall, riparian processes appear to reduce but not eliminate hydrologic losses of N following catastrophic disturbance. The nature of the long-term biogeochemical response to disturbance in this tropical rain forest ecosystem is similar to that observed in some montane temperate forests, and the time course of recovery appears to be associated with the speed with which vegetation regrows following disturbance.

Natural Woodland: Ecology and Conservation in Northern Temperate Regions.

Preface Part I. Definitions, Significance and Survival: 1. Woodlands, nature and history: a personal introduction 2. Definitions, values and philosophies 3. Natural woodland in Europe and North America Part II. Temperate and Boreal Natural Forests: 4. Selected virgin forests 5. Disturbance in natural woodland 6. Succession after catastrophic disturbances 7. Structures and dynamics of old-growth forests 8. Components of the forest 9. Wildlife of natural woodlands Part III. Virgin Forest Remnants: 10. Human impacts on natural forests in North America 11. Wildlife responses to the modification of natural forests 12. Protecting virgin forest remnants Part IV. Natural Features in the Conservation of British Woodlands: 13. Woodland nature conservation: development, rationale and practice 14. British natural woodlands 15. Reconstructing British natural woodlands 16. Management of broadleaved woodland 17. Design and management of upland conifer plantations 18. Priorities in woodland nature conservation Appendix Bibliography Indexes.

Catastrophic disturbance, logging and the ecology of mahogany (Swietenia macrophylla King): grounds for listing a major tropical timber species in CITES

Recent debate on whether or not mahogany (Swietenia macrophylla King) is threatened by the international timber trade has focused on the breadth of its range and estimates of the remaining stock of mahogany trees. These data are inadequate to reveal the status of mahogany populations, both because they are incomplete in areal extent and because they do not reveal population parameters such as the existence or density of young trees smaller than commercial size. However, there is sufficient information on the regeneration ecology of mahogany to indicate that under natural conditions this species regenerates in essentially even-aged stands after catastrophic disturbances destroy many or most trees, and, in the case of fires and flooding, saplings and seedlings as well. Adult mahoganies tend to survive these events, and regenerate by shedding seed onto the resulting gaps or clearings. This ecological strategy makes mahogany vulnerable to logging, first because juvenile mahoganies are not found in the understorey, and secondly because logging operations shortcircuit mahogany regeneration processes by selectively removing almost all mahogany seed sources while leaving standing competing vegetation of other species. Listing of mahogany in CITES Appendix II could provide both a mechanism to fill in gaps in information and an incentive to change current practices in favour of silvicultural management to provide for regeneration of this valuable timber species in forests subjected to logging.

Effects of Sampling Area and Subsampling Procedure on Comparisons of Taxa Richness among Streams

the biotic integrity of communities. In all cases, we make the implicit and sometimes brash assumption that we can really measure the number of taxa in a community. Although measuring taxa richness might appear straightforward, accurate measurement has been extraordinarily difficult; and despite years of effort, no universally accepted methods for its measurement have emerged. The essential problem is that we can never completely census a taxonomic assemblage or entire community; we rely instead on estimates that describe some portion of the real taxa richness of an assemblage. The problem of knowing what percent of the taxa present have been collected is exacerbated when investigators fail to explicitly define their universe of interest (i.e., the spatial bounds of the community or communities in question). Comparisons of taxa richness among studies that used different sampling and subsampling methods are especially difficult and should be viewed skeptically. The difficulty of obtaining accurate measurements of richness is due to the collector's curve

A risk assessment of landscape hazards for building sites in the Front Range mountains of Colorado

Abstract Predictive spatial modelling is becoming an integral part of landscape planning. One emerging modelling approach is risk assessment. This paper illustrates the application of risk assessment techniques within a regional context for landscape planning and design, as urban development expands into mountainous building environments. The investigation examines the susceptibility of building sites in a portion of the Front Range mountains of Colorado/Wyoming to catastrophic disturbance by four landscape hazards: flooding, rockfall, fire and avalanche. A hazard rating model is applied to a portion of the Front Range, the Pingree Park vicinity, by employing geographic information system technology. We discovered that, below the tree‐line, approximately 75% of the landscape contained a high risk rating and the remaining portion a moderate risk rating. This study implies that there is no long‐term, safe building site in the study area. Assuming that the Pingree Park vicinity is a representative sample of ...

Role of catastrophic disturbance in mediating Nucella-Mytilus interactions in the Alaskan rocky intertidal

MEPS Marine Ecology Progress Series Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsTheme Sections MEPS 138:125-133 (1996) - doi:10.3354/meps138125 Role of catastrophic disturbance in mediating Nucella-Mytilus interactions in the Alaskan rocky intertidal Carroll ML, Highsmith RC The mussel Mytilus trossulus is typically a dominant competitor and principal space-occupying species in the rocky mid-intertidal zone of south central Alaskan (USA). Its principal predator in the region is the whelk Nucella lima. We examined predator-prey interactions between M. trossulus and N. lima following a severe freeze which greatly reduced mussel abundance in the upper portion of their vertical range. N. lima in Kachemak Bay was locally abundant, but its spatial distribution was patchy, resulting in site-to-site variation in predation intensity. Following the freeze, mussel populations recovered to occupy 72% of primary space at a site where N. lima was rare. At sites where N. lima occurred in high densities (&GT100 m-2), mussel cover remained significantly lower. At the latter sites, up to 81% of mussel mortality was due to snail predation. In field trials, average densities of N. lima significantly reduced mussel cover within 2 wk. From published literature on Nucella sp. feeding rates and our data on in situ reductions in mussel beds, we estimate that N. lima can eliminate 60 to 90% of mussels at a given site in 1 season. In contrast to the general view that mussel recovery from disturbance is inevitable, our results indicate that local populations of young mussels were unable to increase space utilization because of intense N. lima predation. A stochastic, catastrophic disturbance event thus altered control of community structure by removing dense stands of large prey individuals that had grown to near-refuge size. This facilitated long-term N. lima control of what had been a mussel-dominated community by shifting the interaction toward smaller sized mussels that are susceptible to intense predation. Alaska . Community structure . Disturbance . Indirect effects . Rocky intertidal . Predation . Mytilus . Nucella Full text in pdf format PreviousNextExport citation RSS - Facebook - Tweet - linkedIn Cited by Published in MEPS Vol. 138. Publication date: July 25, 1996 Print ISSN:0171-8630; Online ISSN:1616-1599 Copyright © 1996 Inter-Research.

Thirty-eight years of autogenic, woody understory dynamics in a mature, temperate pine–oak forest

In 1935, 32 ha of a pine–hardwood forest were set aside from future timber management in southern Arkansas, U.S.A. Old-growth timber had been cut to a 36-cm stump diameter before 1915. Between 1952 and 1993, four inventories were made of the overstory and midstory components (number of live trees ≥9 cm in diameter breast height (DBH) taken at 1.37 m, by 2.54-cm DBH classes). Between 1954 and 1992, four corresponding inventories were made of the woody understory vegetation (>15 cm tall but <9 cm DBH) by counting rootstocks within 52 systematically spaced 8-m2 circular quadrats. Understory species importance values (relative density + relative height + relative frequency) were used to compute diversity and similarity indices. During 38 years of assessment, no catastrophic disturbances occurred within the 32-ha forest. Although loblolly pine (Pinustaeda L.) and shortleaf pine (Pinusechinata Mill.) dominated the overstory (64% of basal area in 1954 and 63% in 1993), pines were absent from the understory in all but seedling size classes for the last 38 years. Woody understory diversity indices were essentially stable for 38 years, but the similarity of understory species tended to decline as the time between inventories increased. Relative importance values for woody understory species tended to increase for the more shade-tolerant genera and decrease for less tolerant genera. Survival and height growth of woody understory species were also found to be positively correlated with shade tolerance.

Nutrient Accumulation during Primary Succession in a Montane Tropical Forest, Puerto Rico

AbstractFew studies document both above‐ and belowground changes in ecosystem nutrient capital with successional time. This study was conducted to assess the resiliency of soil and biomass nutrient capital in a montane tropical forest following catastrophic disturbance. We report measurements of soil and biomass C, N, P, K, Ca, and Mg pools in a chronosequence of landslide scars ranging from 1 to >55 yr (n = 12) in the Luquillo Experimental Forest, Puerto Rico. Pool sizes are also reported for plots located in the two late‐succession vegetation associations, which represent both potential mature forest stages for aggrading landslide scars and the dominant predisturbance forest types at that elevation: the palm brake forest (n = 3), dominated by sierra palm [Prestoea montana (R. Grah.) Nichols], and the palo colorado forest (n = 5), dominated by palo colorado [Cyrilla racemiflora L.] and other dicots. The soils of new landslide scars contain much less exchangeable nutrient cation capital than that present in biomass + soil exchange pools in either of the mature forest types or in the >55‐yr landslide scars. Nonetheless, recovery of N, P, K, and Mg to levels present in both mature forest associations occurs during the brief course of this primary succession chronosequence, suggesting that forest recovery is not limited by the availability of those nutrients. Recovery of C and Ca pools is apparently slower.

Longterm response of disturbance landscapes to human intervention and global change

The structure of landscapes subject to patch-forming catastrophic disturbances, or “disturbance landscapes”, is controlled by the characteristics of the disturbance regime, including the distribution of disturbance sizes and intervals, and the rotation time. The primary landscape structure in disturbance landscapes is the structure of the mosaic of disturbance patches, which can be described by indices such as patch size and shape. The purpose of this research was to use a geographical information system-based spatial model (DISPATCH) to simulate the effects of the initial density of patches on the rate of response to alteration of a disturbance regime, the effects of global warming and cooling, and the effects of fragmentation and restoration, on the structure of a generalized temperate-zone forested disturbance landscape over a period of 400 yr. The simulations suggest that landscapes require 1/2 to 2 rotations of a new disturbance regime to adjust to that regime regardless of the size and interval distributions. Thus alterations that shorten rotations, as would be the case if global warming increases fire sizes and decreases fire intervals, produce a more rapid response than do alterations that lengthen rotations, such as cooling and fire suppression. Landscape with long rotations may be in perpetual disequilibrium with their disturbance regimes due to a mismatch between their adjustment rate and the rate of climatic change. Landscapes with similar rotation times may have different structures, because size and interval distributions independently affect landscape structure. The response of disturbance landscapes to changing disturbance regimes is governed by both the number and size of patch births.

Catastrophic Decline of a Desert Rodent, Dipodomys spectabilis: Insights from a Long-Term Study

We describe the catastrophic decline of a species of keystone rodent at a Chihuahuan Desert site. The population density of Dipodomys spectabilis averaged 7.6 individuals/ha from 1977 to 1983, but declined to near extinction over the winter of 1983–1984. We propose hypotheses to explain this decline: 1) disease; 2) damage to seed stores by heavy precipitation; 3) contamination of seed stores by mycotoxins. Available data cannot conclusively distinguish these possibilities, but they implicate tropical storm Octave and favor hypotheses 2 and 3. The decline of D. spectabilis was followed by increased abundance of three species of a rodents and a sharp decline in another, Perognathus flavus . Long-term studies can provide unique insights into the nature, magnitude, and consequences of infrequent catastrophic disturbances.

Structure and regeneration of canopy species in an old-growth evergreen broad-leaved forest in Aya district, southwestern Japan

The population structure and regeneration of canopy species were studied in a 4 ha plot in an old-growth evergreen broad-leaved forest in the Aya district of southwestern Japan. The 200 m × 200 m plot contained 50 tree species, including 22 canopy species, 3,904 trees (dbh≥5 cm) and a total basal area of 48.3 m2/ha. Forty one gaps occurred within the plot, and both the average gap size (67.3 m2) and the total area of gap to plot area (6.9%) were small. Species found in the canopy in the plot were divided into three groups (A, B, C) based on size and spatial distribution patterns, and density in each tree size. Group A (typical species: Distylium racemosum, Persea japonica) showed a high density, nearly random distribution and an inverse J-shaped size distribution. Species in group B (Quercus salicina, Quercus acuta, Quercus gilva) were distributed contagiously with conspicuous concentration of small trees (<5 cm dbh) around gaps. However, the species in this group included few trees likely to reach the canopy in the near future. Group C included fast-growing pioneer and shade intolerant species (e.g. Cornus controversa, Carpinus tschonoskii, Fagara ailanthoides), which formed large clumps. Most gaps were not characterized by successful regeneration of group B and C but did appear to accelerate the growth of group A. Group B species appear to require long-lived or large gaps while group C species require large, catastrophic disturbances, such as landslides, for regeneration.

Macrofossil Casuarinaceae: their identification and the oldest macrofossil record, Gymnostoma antiquum sp. nov., from the late paleocene of New South Wales, Australia

The oldest known Casuarinaceae macrofossils, from late Paleocene sediments at Lake Bungarby in New South Wales, are assigned to a new species of Casuarinaceae, Gymnostoma antiquum. The nearest living relatives of this species are the Papua New Guinean Gymnostoma species and in particular one as yet unnamed species. Previous problems relating to the preparation, identification and description of Casuarinaceae macrofossils are examined and clarified. The ecology of both living Gymnostoma and G. antiquum are discussed. The decrease in catastrophic disturbance and climate seasonality during the Cenozoic were probably major contributing factors leading to the current distribution of Gymnostoma.