Forests, fire and vegetation change impacts on Murray-Darling basin water resources

The Murray-Darling River system is perhaps Australia’s most important, with significant social, cultural and environmental values including 16 Ramsar listed wetlands. The MDB is home to 2.6 million people and produces about $24 billion worth in agricultural production each year (about one-third of total value for Australia). Hydrologic issues, typified by water availability and quality, have existed for many years, peaking during the Millennium drought from 1997 to 2010. Competing interests (i.e. irrigation, tourism, environmental heath), and the declining flows and water quality during droughts, led governments and water management agencies to consider the risks to water resources in the system in the early-mid 2000s. This paper reviews changes to risks associated with forest dynamics, as identified by - afforestation and bushfire–and considers new issues that have emerged since that analysis. It was found that the potential impacts of bushfire on stream flows were over-estimated in past studies, and that a planned significant afforestation expansion into agricultural and grazing land that was projected to reduce stream flows did not occur. While these two risks now do not seem likely to have significant future impacts on flows, or consequent effects on downstream users, the interaction of elevated CO2 and increasing temperatures on vegetation functioning and subsequent hydrologic consequences at catchment scale require further research and analysis. Reduced rainfall and increased temperatures under future climate change are likely to have an impact on inputs and flows. Uncertainties in how these changes, and feedbacks between climate, drought, more frequent fire and vegetation responses, impact on system hydrology also require further investigation

Impacts of wildfire and post‐fire land management on hydrological and sediment processes in a humid Mediterranean headwater catchment

The extensive afforestation of the Mediterranean rim of Europe in recent decades has increased the number of wildfire disturbances on hydrological and sediment processes, but the impacts on headwater catchments is still poorly understood, especially when compared with the previous agricultural landscape. This work monitored an agroforestry catchment in the north-western Iberian Peninsula, with plantation forests mixed with traditional agriculture using soil conservation practices, for one year before the fire and for three years afterwards, during which period the burnt area was plowed and reforested. During this period, continuous data was collected for meteorology, streamflow and sediment concentration at the outlet, erosion features were mapped and measured after major rainfall events, and channel sediment dynamics were monitored downstream from the agricultural and the burnt forest area. Data from 202 rainfall events with over 10 mm was analysed in detail. Results show that the fire led to a notable impact on sediment processes during the first two post-fire years, but not on streamflow processes; this despite the small size of the burnt area (10% of the catchment) and the occurrence of a severe drought in the first year after the fire. During this period, soil loss at the burnt forest slopes was much larger than that at most traditionally managed fields, and, ultimately, led to sediment exhaustion. At the catchment scale, storm characteristics were the dominant factor behind streamflow and sediment yield both before and after the fire. However, the data indicated a shift from detachment-limited sediment yield before the fire, to transport-limited sediment yield afterwards, with important increases in streamflow sediment concentration. This indicates that even small fires can temporarily change sediment processes in agroforestry catchments, with potential negative consequences for downstream water quality.info:eu-repo/semantics/publishedVersio

The relationship between fire severity and eucalypt health: implications for forest structure and carbon balance

The capacity of resprouting eucalypts to regenerate foliage determines the extent of fire induced structural change and carbon dynamics within Australian dry sclerophyll forests. Resprouting eucalypts are traditionally considered resilient to severe fire, yet records of post-fire mortality are highly varied, reflecting the limited sample size of previous studies and the complexity of factors that govern stem death. Fire regimes are predicted to become increasingly severe throughout Mediterranean ecosystems under anthropogenic climate change, increasing the risk of carbon loss within forest communities. This study sought to further the ecological understanding of the effects of fire severity on eucalypt mortality and coarse woody debris (CWD) dynamics within dry sclerophyll communities across southeast Australia. The extent of tissue death and the occurrence of resprouting were used to quantify the health response of eucalypts to fire disturbance. CWD was assessed using van Wagner’s line-intercept method. Relevant additional data was obtained from the NSW Bushfire Risk Management Research Hub. Fire severity and fire frequency values were derived from digital fire extent and severity maps based on satellite imagery. As predicted, eucalypt stem mortality was significantly influenced by stem diameter and fire severity, such that rates of stem death were greatest for small stems under extreme severity fire. Furthermore, stem mortality was significantly influenced by bark type, with smooth bark stems generally the most resilient to fire disturbance. CWD biomass was not significantly influenced by fire severity or frequency yet was significantly affected by fire type. CWD was reduced in plots burnt by prescribed fire and heightened in plots burnt by wildfire, relative to long unburnt forest. This suggests that lower intensity prescribed burns consume more CWD than they produce, whilst CWD production exceeds consumption under higher intensity wildfires. This study provides the largest and most reliable field-based estimates of stem death in dry sclerophyll forests to date. Under more severe fire regimes, disproportionate age class and bark type mortality will likely decrease forest diversity and structural complexity. Both CWD production and consumption will likely increased under future fire regimes, leading to a possible reduction in forest carbon if the consumption of dead wood exceeds the production of live biomass. Whilst gradual carbon loss and demographic shifts are 4 expected under more severe fire regimes, complete ecosystem transformation of resprouting eucalypt forests seems unlikely in the near future, given the persistence of the majority of large trees and the rapid development of lignotubers in small stems which often prevents whole tree mortality

How do large wildfires impact sediment redistribution over multiple decades?

Wildfires have become an increasing threat for Mediterranean ecosystems, due to increasing climate change-induced wildfire activity and changing land management practices. In addition to the initial risk, wildfires can alter the soil in various ways—depending on fire severity—and cause enhanced post-fire erosion. Usually, post-fire erosion studies focus on a short time window and lack the attention for sediment dynamics at larger spatial scales. Yet, these large spatial and temporal scales are fundamental for a better understanding of long-term destructive effects of multiple recurring wildfires on post-fire erosion processes and catchment sediment dynamics. In this study the landscape evolution model LAPSUS was used to simulate erosion and deposition in the 404 km2 Águeda catchment in north-central Portugal over a 41-year (1979–2020) timespan, including eight wildfires each burning >1000 ha. To include variation in fire severity and its impact on the soil, four burn severity classes, represented by the difference normalized burn ratio (dNBR), were parameterized. Although model calibration was difficult due to lack of spatial and temporal measured data, the results show that long-term post-fire net erosion rates were significantly higher in the wildfire scenarios (5.95 ton ha−1 yr−1) compared to those of a non-wildfire scenario (0.58 ton ha−1 yr−1). Furthermore, erosion values increased with burn severity and multiple wildfires increased the overall catchment sediment build-up. Simulated erosion patterns showed great spatial variability, with large deposition and erosion rates inside streams. This variability made it difficult to identify land uses that were most sensitive for post-fire erosion, because some land uses were located in more erosion-sensitive areas (e.g. streams, gullies) or were more affected by high burn severity levels than others. Despite these limitations, LAPSUS performed well on addressing spatial sediment processes and can contribute to pre-fire management strategies, by identifying locations at risk of post-fire erosion.info:eu-repo/semantics/publishedVersio

Estudo e modelação dos processos hidrológicos e erosivos em bacias hidrográficas ardidas

Doutoramento em Ciências e Engenharia do AmbienteForest fires implications in overland flow and soil erosion have been researched for several years. Therefore, is widely known that fires enhance hydrological and geomorphological activity worldwide as also in Mediterranean areas. Soil burn severity has been widely used to describe the impacts of fire on soils, and has being recognized as a decisive factor controlling post-fire erosion rates. However, there is no unique definition of the term and the relationship between soil burn severity and post-fire hydrological and erosion response has not yet been fully established. Few studies have assessed post-fire erosion over multiple years, and the authors are aware of none which assess runoff. Small amount of studies concerning pre-fire management practices were also found. In the case of soil erosion models, the Revised Universal Soil Loss Equation (RUSLE) and the revised Morgan–Morgan–Finney (MMF) are well-known models, but not much information is available as regards their suitability in predicting post-fire soil erosion in forest soils. The lack of information is even more pronounced as regards post-fire rehabilitation treatments. The aim of the thesis was to perform an extensive research under the post fire hydrologic and erosive response subject. By understanding the effect of burn severity in ecosystems and its implications regarding post fire hydrological and erosive responses worldwide. Test the effect of different pre-fire land management practices (unplowed, downslope plowed and contour plowed) and time-since-fire, in the post fire hydrological and erosive response, between the two most common land uses in Portugal (pine and eucalypt). Assess the performance of two widely-known erosion models (RUSLE and Revised MMF), to predict soil erosion rates during first year following two wildfires of distinctive burn severity. Furthermore, to apply these two models considering different post-fire rehabilitation treatments in an area severely affected by fire. Improve model estimations of post-fire runoff and erosion rates in two different land uses (pine and eucalypt) using the revised MMF. To assess these improvements by comparing estimations and measurements of runoff and erosion, in two recently burned sites, as also with their post fire rehabilitation treatments. Model modifications involved: (1) focusing on intra-annual changes in parameters to incorporate seasonal differences in runoff and erosion; and (2) inclusion of soil water repellency in runoff predictions. Additionally, validate these improvements with the application of the model to other pine and eucalypt sites in Central Portugal. The review and meta-analysis showed that fire occurrence had a significant effect on the hydrological and erosive response. However, this effect was only significantly higher with increasing soil burn severity for inter-rill erosion, and not for runoff. This study furthermore highlighted the incoherencies between existing burn severity classifications, and proposed an unambiguous classification. In the case of the erosion plots with natural rainfall, land use factor affected annual runoff while land management affected both annual runoff and erosion amounts significantly. Time-since-fire had an important effect in erosion amounts among unplowed sites, while for eucalypt sites time affected both annual runoff and erosion amounts. At all studied sites runoff coefficients increase over the four years of monitoring. In the other hand, sediment concentration in the runoff, recorded a decrease during the same period. Reasons for divergence from the classic post-fire recovery model were also explored. Short fire recurrence intervals and forest management practices are viewed as the main reasons for the observed severe and continuing soil degradation. The revised MMF model presented reasonable accuracy in the predictions while the RUSLE clearly overestimated the observed erosion rates. After improvements: the revised model was able to predict first-year post-fire plot-scale runoff and erosion rates for both forest types, these predictions were improved both by the seasonal changes in the model parameters; and by considering the effect of soil water repellency on the runoff, individual seasonal predictions were considered accurate, and the inclusion of the soil water repellency in the model also improved the model at this base. The revised MMF model proved capable of providing a simple set of criteria for management decisions about runoff and erosion mitigation measures in burned areas. The erosion predictions at the validation sites attested both to the robustness of the model and of the calibration parameters, suggesting a potential wider application.As implicações dos fogos florestais na escorrência superficial e erosão dos solos têm sido objeto de estudo desde há vários anos. Como tal, é do conhecimento geral, que os fogos tendem a aumentar a atividade hidrológica e geomorfológica em todo o mundo e também nas zonas mediterrânicas. A severidade da queima do solo tem sido utilizada para descrever o impacto dos fogos nos solos e reconhecida como um fator decisivo no controle das taxas de erosão pós-fogo. No entanto, não existe uma definição única do termo e a relação entre severidade de queima do solo com a resposta hidrológica e erosiva não é ainda totalmente conhecida. Por outro lado, escasseiam os estudos com registos de taxas de erosão pós-fogo durante um período de quatro anos, nenhum dentro desse período com registos de escorrência superficial pós-fogo. Menos estudos ainda, que retratem a resposta erosiva pós-fogo, mencionando práticas de gestão florestal anteriores ao mesmo. No caso da modelação de erosão dos solos, apesar dos modelos aplicados ‒ a Equação Universal de Perdas do Solo Revista (RUSLE) e o modelo de Morgan-Morgan-Finney (MMF) ‒ serem bem conhecidos, a informação referente à sua aplicabilidade para prever taxas de erosão em solos florestais após o fogo é bastante limitada. No caso da aplicabilidade destes modelos, considerando tratamentos de mitigação após incêndio, ainda menos informação existe. O objetivo deste trabalho é o aprofundar do conhecimento relativo à resposta hidrológica e erosiva após incêndios florestais através do estudo dos efeitos da severidade de queima nos ecossistemas e das suas implicações na resposta hidrológica e erosiva em todo o mundo. Para este fim, testámos também o efeito de diferentes práticas de gestão florestal (não lavrado, lavrado no sentido do declive e lavrado segundo as curvas de nível), executadas previamente ao incêndio florestal, entre dois dos usos do solo mais comuns em Portugal: o pinheiro e o eucalipto. Testámos ainda a eficiência com que dois modelos, amplamente conhecidos (RUSLE e MMF revisto), conseguem prever, em duas severidades distintas e com tratamentos de reabilitação pós fogo, as taxas de erosão durante o ano que seguiu ao incêndio florestal. Com essa informação, que veio melhorar as estimativas, alterámos o modelo e verificámos a sua eficiência, tanto nas previsões de escorrência superficial como na erosão do solo em pós-fogo e em pós-fogo com tratamentos de reabilitação. Essas alterações, que consistiam em (1) passar todos os inputs numa escala sazonal para incorporar as variações sazonais sentidas na formação de escorrência superficial e erosão do solo, e (2) inclusão do efeito hidrófobo do solo à água nas previsões da escorrência superficial. Adicionalmente, validar estas melhorias noutra área florestal independente no centro de Portugal para pinhal e eucaliptal, pós-fogo e pós-fogo com tratamentos de reabilitação. A revisão e a meta-análise demonstraram que a ocorrência de um fogo florestal provoca alterações significativas na resposta hidrológica e erosiva. No entanto, este efeito só é significativamente diferente com o aumento da severidade da queima do solo para a erosão e não para a geração de escorrência superficial. Este estudo também aludiu a incoerência entre várias classificações de severidade de queima e propõe ainda uma classificação não ambígua. No caso das parcelas de erosão com chuva natural, verificou-se que o uso do solo é um fator que afeta a geração de escorrência; em contrapartida, a gestão florestal afeta tanto a escorrência como a erosão do solo. O tempo decorrido desde o incêndio surge como fator de elevada importância entre locais não lavrados, relativamente às perdas de solo, e entre eucaliptais, relativamente à escorrência e erosão. Em todos os locais os coeficientes de escorrência aumentaram do primeiro para o quarto ano de estudo. Noutra nota, notou-se um decréscimo nas concentrações de sedimentos na escorrência durante o mesmo período. Foi explorada a discrepância entre este estudo e entre os modelos clássicos de recuperação pós-fogo; também o curto intervalo entre fogos e as constantes práticas de gestão florestal são vistas como as principais razões pela severa e continuada degradação dos solos. O modelo de MMF revisto apresentou uma razoável acuidade nas previsões enquanto que, o RUSLE claramente sobrestimou as taxas de erosão observadas. Ambos os modelos demonstraram capacidades para serem usados como ferramentas operacionais para ajudarem gestores a determinar áreas de risco de erosão pós-fogo e a tomarem ações prioritárias. O Modelo MMF revisto permitiu determinar as taxas de erosão durante o primeiro ano, após o fogo, para os dois usos do solo estudados: o pinheiro e o eucalipto. Essas previsões melhoraram com a implementação da modelação sazonal e com a inclusão da hidrofobia do solo à água para as previsões de escorrência. Por fim, o modelo de MMF revisto provou ser capaz de providenciar um conjunto de critérios para ajudar à tomada de decisões por parte dos gestores relativamente à escorrência, erosão e tratamentos de mitigação em áreas recentemente ardidas. Este modelo sugere, segundo os resultados obtidos aquando da validação e calibração, uma elevada robustez e um potencial de ser aplicado a outras áreas

Comparisons of vegetation recovery post-fire, logging and salvage logging in the Victorian Central Highlands

ABSTRACT Disturbance is an important ecological driver of plant community composition and adaption. My research was in the Mountain Ash (Eucalyptus regnans) forests of the Central Highlands in Victoria where the primary forms of disturbance are wildfire and clearfell logging. Three large conflagrations in 1939, 1983 and 2009 resulted in uniformly aged stands of Eucalyptus regnans. My research, comprising four interrelated studies, uses these major fire events and recent logging, to compare the recovery attributes of the plants in Mountain Ash forest. Chapter one compares plant species richness and functional group responses to logging and fire of different intensities. I found species richness declined across a 'disturbance gradient' of low severity fire (30.1species/site), high severity fire (28.9spp/site), clearfell logging (25.1spp/site) and salvage logging (21.7spp/site). The greatest differences between the effects of fire and logging are on sprouting species including ferns and midstorey trees, with logging causing a simplification of the forest biota. Species losses are attributed to the mechanical disturbance of harvesting and the fire/logging disturbance sequence. Chapter two studies growth rates of tree ferns, Cyathea australis and Dicksonia antarctica. Five years after the 2009 fires, I measured the new growth of 335 tree ferns and found Cyathea australis averaged 73(+/- 22)mm/year of growth, while Dicksonia antarctica averaged 33(+/- 13)mm/year. An unexpected finding was higher growth rates in taller tree ferns, increasing with height by 5-6mm/yr/m in both species. The non-linear growth is explained by the taller ferns being exposed to greater amounts of sunlight as the dense regeneration progressively shaded the shorter ferns. In Chapter three, I use a chronosequence from the major fire events of 2009, 1983, 1939 and 1851 to determine how species richness and functional groups differ in forests of different ages. Species richness is highest in the youngest cohort (17.1species/plot) when many early successional species are still present. The 1983 and 1939 cohorts have the lowest species richness (12.9 and 12.5 species/plot respectively) while the 1851 cohort has 13.4spp/plot. Sprouting species such as ferns and midstorey trees were most common in the older cohorts, while seeding species dominated the youngest. The presence of 12 species unique to the two oldest cohorts suggests Relay Floristics may best describe the successional pathway of this forest. Chapter four examined how forest age prior to a disturbance affects subsequent regeneration cohorts. Using forest burned in 2009 that was 26, 70 and 158+ years of age at the time of the fire, I found species richness decreased with forest age (25.7, 22.7 and 20.7 species/site respectively). The diverse seeding species group, was most abundant in the youngest cohort, while sprouting species including ferns were the only functional group to increase with forest age. My research concludes that Mountain Ash forests are resilient to fire, however, keystone species that resprout, like tree ferns and midstorey trees are susceptible to logging. Sprouting species increase with time since disturbance and as with other biological legacies, sprouting species need to be carefully managed for during logging operations

Integration of fire management in forest planning management in Portugal

Doutoramento em Engenharia Florestal e dos Recursos Naturais - Instituto Superior de AgronomiaThe importance of ecological and socio - economic forest fires shows the relevance of research techniques and approaches for integrating the planning processes of forest management and fire management . This PhD aimed to investigate these approaches and contributing to the effectiveness of strategies for preventing fires both at the stand level or landscape level. In this context, probabilistic models of fire occurrence and estimated mortality to the main Portuguese forest species (maritime pine and eucalyptus) in pure composition of regular and irregular structures were developed. These were later integrated into a management model that optimizes harvests scheduling for each stand in order to create more fire resistant landscapes. It’s being developed a technologic platform to test these models and their combination with an innovative approach to incorporate fire risk and protective objectives in forest management planning

Assessment of the hydrological effect of drought and fire events on evapotranspiration at a regional scale

Doutoramento em Engenharia Florestal e dos Recursos Naturais - Instituto Superior de Agronomia / ULUntil today, there is only little knowledge about the behavior of actual evapotranspiration (ETa) before and after wildfires in Portugal, which can be estimated from remote sensing techniques. In this thesis, an existing Simplified Two-Source Energy Balance model (STSEB) was adapted, based on moderate resolution imagery to estimate ETa and its contributing parts of transpiration and evaporation. The study served to test the model and its precision. A bias of about 1 mm d1 for the estimated ETa was observed, where evaporation was regularly overestimated and transpiration underestimated. This error is acceptable for two-layer models based on satellite imagery, but estimates cannot be used for irrigation management. The evolution of the estimated ETa after wildfires (up to four years) was analyzed at eucalypt stands at the Caramulo mountain range in Portugal. By investigating the recovery of ETa after wildfire, the difference between burnt and unburnt stands was mainly related to fire severity and stand characteristics. Two to three years after the fire events, the difference between burnt and unburnt stands became nonsignificant for all severity classes. At the same region, the prediction of soil moisture deficit from drought indices was tested. The drought indices empirically estimate the dryness of an area and are directly related to fire danger. They are based on a simple water balance equation where effective rainfall and ETa are the only input and output, respectively. In this work the empirical equation of (ETa) was substituted by the estimated ETa from STSEB, which enhanced the spatial resolution of the drought indices, being regularly interpolated from point estimates. Spatial patterns of soil moisture deficit were predicted, which indicated a relationship to fire occurrences. To conclude, the ETa estimated by the remote sensing based STSEB model, was used to make observations of the water cycle on a regional scale. In contrast to other post-fire studies, eucalypt stands in Portugal were found to be subject to a smaller hydrological impact after wildfires. This implies a fast recovery and a smaller influence on streamflow and groundwater resources. Furthermore, the drought indices, using the ETa from STSEB, identified areas with higher proneness to drought, by improving the spatial resolution, using satellite imagery compared to traditional interpolation techniques. The results support fire danger rating and might help to improve fire regime and forest managementN/

The effects of drought and wildfire on forest structure and carbon storage in a resprouting eucalypt forest

The frequency and intensity of forest disturbances are projected to increase in many regions as climate changes, with an increased likelihood of multiple disturbance events occurring in short succession. The effects and importance of multiple disturbance events are gaining increasing attention but there is substantial uncertainty regarding the strength of interactions in relation to type, sequence, and relative timing. Forests play an integral role in climate change mitigation efforts, however, multiple disturbances could alter forest carbon dynamics, potentially reducing the storage capacity of impacted stands. Accurate accounting of carbon losses and transformations is thus imperative across forests globally, and particularly in non-conifer dominated types and with different responses such as resprouting. This study investigated the effects of a global change-type drought (2010-11) and the Waroona Fire (2016), singularly on forest carbon dynamics in the regrowth Northern Jarrah (Eucalyptus marginata) Forest of southwestern Australia. This was followed by an investigation of the additive and interactive effects of these two disturbances on forest structure and recruitment. The affected forest stands were assessed using a plot-based forest inventory method combined with allometric equations and remote sensing metrics to determine carbon transformations and fire severity. Following the drought die-off there was a significant loss of live standing carbon (49.3 t C ha-1), and a corresponding significant increase in the dead standing carbon pool six months after the drought. The Waroona Fire caused pyrogenic carbon emissions of between 10 and 21 t C ha-1, which corresponded to 5.5-12.2% of the mean pre-fire carbon storage, and the conversion of 59.2 – 72.8 t C ha-1 from the live to dead standing tree pool. This carbon, which comprises another 30-37% of the pre-fire carbon storage will be susceptible to loss over time both from decomposition and from future fires. Total immediate carbon emissions from the 360 km2 wildfire were estimated at 723,113 t C. When the disturbances were examined in combination there was no evidence of linked or compounding effects of these disturbances. Instead a strong effect of wildfire on live basal area (-20.7 ± 7.3 m2 ha-1) overwhelmed pre-existing drought impacts. Eucalypt resprouting forests are particularly resilient, with focal species able to survive multiple stressors over a short time period. However, the newly regrowing burnt stands are vulnerable to future disturbance until they develop bark thick enough to withstand fire, and carbon stores to maintain resprouts following drought. The drought event preferentially removed large trees and the wildfire smaller trees from the live standing carbon pool. With a continually decreasing rainfall and projections of more frequent and severe fires in this area the trajectory of the regrowth in these stands is likely to be strongly tied to the future disturbance regime. Increases in disturbance frequency and intensity may therefore lessen the chances of these forests recovering to pre-fire structure and therefore carbon storage capacity

Logging and fire regimes alter plant communities

Disturbances are key drivers of plant community composition, structure, and function. Plant functional traits, including life forms and reproductive strategies are critical to the resilience and resistance of plant communities in the event of disturbance. Climate change and increasing anthropogenic disturbance are altering natural disturbance regimes globally. When these regimes shift beyond the adaptive resilience of plant functional traits, local populations and ecosystem functions can become compromised. We tested the influence of multiple disturbances, of varying intensity and frequency, on the composition and abundance of vascular plant communities and their respective functional traits (life forms and reproductive strategies) in the wet sclerophyll, Mountain Ash Eucalyptus regnans forests of southeastern Australia. Specifically, we quantified the effect of the type and number of disturbances (including fires, clearcut logging, and salvage logging) on plant community composition. We found that clearcut and salvage logging and the number of fires significantly influenced plant community composition and functional traits. Specifically, multiple fires resulted in lower populations of species that depend on on‐site seeding for persistence. This includes the common tree species Eucalyptus regnans, Pomaderris aspera, and Acacia dealbata. In contrast, clearcut and salvage logged sites supported abundant on‐site seeder species. However, species that depend on resprouting by surviving individuals, such as common and keystone “tree ferns” Dicksonia antarctica and Cyathea australis, declined significantly. Our data have important implications for understanding the relationship between altered disturbance regimes and plant communities and the respective effects on ecosystem function. In a period of rapid global environmental change, with disturbances predicted to increase and intensify, it is critical to address the impact of altered disturbance regimes on biodiversity.Supporting funding was provided by The Australian National University and the Paddy Pallin Foundation