Michael J. Lawes

Michael J. Lawes
University of KwaZulu-Natal | ukzn · School of Life Sciences

PhD

About

236
Publications
72,076
Reads
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Citations
Introduction
Michael J. Lawes does research in Zoology, Botany, Ecology and Evolutionary Biology. He is particularly interested in resprouting and bark ecology in response to fire and tree community ecology of rainforest, especially in Africa. Currently working on a review of the history of forest in Africa.
Additional affiliations
December 2007 - present
Charles Darwin University
Position
  • Professor (Full) Wildlife Science
January 1992 - November 2007
University of KwaZulu-Natal
Position
  • Professor

Publications

Publications (236)
Article
Postfire resprouting (R+) and recruitment from seed (S+) are common resilience traits in Australian ecosystems. We classified 2696 woody Australian taxa as R+ or not (R−) and as S+ or not (S−). The proportions of these traits in Australian ecosystems were examined in relation to fire regimes and other ecological correlates, and by trait mapping on...
Article
Full-text available
With open-access publishing authors often pay an article processing charge and subsequently their article is freely available online. These charges are beyond the reach of most African academics. Thus, the trend towards open-access publishing will shift the business model from a pay-wall model, where access to literature is limited, to a pay-to-pub...
Article
Full-text available
Background Tropical forests are repositories of much of the world’s biodiversity and are critical for mitigation of climate change. Yet, the drivers of forest dynamics are poorly understood. This is in large part due to the lack of long-term data on forest change and changes in drivers. Methodology We quantify changes in tree abundance, diversity,...
Preprint
With open-access publishing authors pay an article processing charge and subsequently their article is freely available online. These charges are beyond the reach of most African academics. Thus, the trend towards open access publishing will shift the business model from a pay-wall model, where access to literature is limited, to a pay-to-publish o...
Article
Half-butt eucalypts (genera: Eucalyptus and Corymbia) have both thick outer bark at the stem base (half-butt) conferring resistance to surface fire, and thin photosynthetic canopy bark that reduces moisture stress. Here we examine how the functional ecology of dual outer bark types influences the wide distribution of Australian half-butt species. W...
Preprint
Full-text available
Background: Tropical forests are repositories of much of the world’s biodiversity and are critical for mitigation of climate change. Yet, the drivers of forest dynamics are poorly understood. This is in large part due to the lack of longitudinal data on forest change and changes in drivers. Methodology: We quantify changes in tree abundance, divers...
Article
Full-text available
ContextInvasive predators are a key threat to biodiversity worldwide. In Australia, feral cats are likely to be responsible for many extinctions of native mammal species in the south and centre of the continent. AimsHere we examine the effect of feral cats on native rodent populations in the second of two translocation experiments. Methods In a wil...
Article
Full-text available
Bark contributes approximately 20% to the total aboveground biomass of trees, yet bark is not properly accounted for when estimating carbon sequestered by trees. Current allometric functions estimate tree volume from diameter measured over the bark, and derive bark density and carbon content from estimates for wood. As the bark density of hardwood...
Article
Full-text available
Aim Palms are an iconic, diverse and often abundant component of tropical ecosystems that provide many ecosystem services. Being monocots, tree palms are evolutionarily, morphologically and physiologically distinct from other trees, and these differences have important consequences for ecosystem services (e.g., carbon sequestration and storage) and...
Article
Full-text available
Aim: Palms are an iconic, diverse and often abundant component of tropical ecosystems that provide many ecosystem services. Being monocots, tree palms are evolutionarily, morphologically and physiologically distinct from other trees, and these differences have important consequences for ecosystem services (e.g., carbon sequestration and storage) an...
Article
Full-text available
Northern Australia's savannas are among the most fire‐prone biomes on Earth and are dominated by eucalypts (Eucalyptus and Corymbia spp.). It is not clear what processes allow this group to dominate under such extreme fire frequencies and whether a superior ability to compete for nutrients and water might play a role. There is evidence that eucalyp...
Article
Terminalia ferdinandiana Exell., also known as the Kakadu plum, is an important food plant endemic to northern Australia. The fruit has substantial commercial demand as it contains sought-after antioxidants and the greatest concentration of ascorbic acid of any fruit known worldwide. Better knowledge of its reproductive biology is required to incre...
Article
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Although conventional wisdom considers knowledge of threatened species' ecology and status essential for conservation , few studies demonstrate this in a quantitative way across many species and within the same political entity. Here, we evaluated the impacts of scientific research against conservation interventions (including funding) and species-...
Article
Full-text available
The Gouldian finch (Erythrura gouldiae, Gould 1844) is a threatened grass finch (Estrildidae) endemic to the tropical savannas of northern Australia. Current fire regimes, consisting of frequent and extensive fire across these savanna grasslands, affect the type and availability of grass seed for granivores. Gouldian finches are particularly affect...
Article
Full-text available
Seeds of native grasses are an important food source for granivorous finches throughout the tropical savannas of northern Australia. The iconic Gouldian finch (Erythrura gouldiae), a threatened species endemic to these savanna grasslands, relies almost exclusively on the grass seeds of annual Sorghum spp. when breeding, and appears to time breeding...
Article
Understanding the role that the vast north Australian savannas play in the continental carbon cycle requires reliable quantification of their carbon stock at landscape and regional scales. LiDAR remote sensing has proven efficient and accurate for the fine-scale estimation of above-ground tree biomass (AGB) and carbon stocks in many ecosystems, but...
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Full-text available
In much of the tropics, the proportion of the land covered by regenerating forest surpasses than in primary forest, thus protecting regenerating forest could offer a valuable conservation opportunity, but only if those lands promote faunal recovery. Chapman et al. documented the recovery of populations of six primate species over up to 45 years in...
Article
Full-text available
Knowledge about the biogeographic affinities of the world’s tropical forests helps to better understand regional differences in forest structure, diversity, composition, and dynamics. Such understanding will enable anticipation of region-specific responses to global environmental change. Modern phylogenies, in combination with broad coverage of spe...
Article
From analysis of results from 93 studies on the frequency of occurrence of birds in cat dietary samples, and a recently published assessment of the population size of feral cats in largely natural landscapes, we estimate and map the number of birds killed annually in Australia by feral cats. We show that average rates of predation on birds by cats...
Article
Full-text available
Ecosystem restoration can help reverse biodiversity loss, but whether faunal communities of forests undergoing restoration converge with those of primary forest over time remains contentious. There is a need to develop faunal indicators of restoration success that more comprehensively reflect changes in biodiversity and ecosystem function. Ants are...
Article
Full-text available
Ecological restoration is increasingly applied in tropical forests to mitigate biodiversity loss and recover ecosystem functions. In restoration ecology, functional richness, rather than species richness, often determines community assembly, and measures of functional diversity provide a mechanistic link between diversity and ecological functioning...
Article
Biodiversity is declining at an alarming rate, especially among vertebrates. Disease is commonly ignored or dismissed in investigations of wildlife declines, partly because there is often little or no obvious clinical evidence of illness. We argue that disease has the potential to cause many species declines and extinctions and that there is mounti...
Technical Report
Full-text available
Conflict between Top End livestock producers and high densities of Agile Wallabies (Macropus agilis) on pastoral land has been ongoing for decades. In recent years, wallaby numbers and densities on pastoral lands have increased dramatically. In some agricultural situations wallaby densities are 1,000 times greater than the natural density (<0.5 ani...
Article
Full-text available
Afrotemperate forests situated in the Drakensberg mountains of South Africa are characteristically small (1–10 s ha) and widely dispersed in a vast fire-prone grassland. Compared with lowland forests, they are typically species poor with low levels of endemism and species turnover, patterns that are to date unexplained. Here we show that the richne...
Article
Reforestation and restoration offer critical contributions to addressing climate change and biodiversity decline. Enabling carbon credits to be derived from these activities is important for reforestation, particularly since reforestation does not come cheaply. Australia’s Carbon Farming Initiative is a world-leading policy that allows carbon credi...
Article
Full-text available
Fire is a pervasive feature of the tropical savannas of northern Australia. Increasingly extensive and intensive fires have had an adverse effect on grass layer diversity. Reduced grass species diversity and abundance are important correlates of the decline of granivores in these tropical savannas. The Gouldian finch (Erythrura gouldiae), an endang...
Article
Plant invasions are threats to biodiversity and ecosystem processes that have far reaching ecological and economic impacts. Understanding the mechanisms of invasion essentially helps in developing effective management strategies. Rubber bush (Calotropis procera) is an introduced milkweed that invades Australian beef production rangelands. Its estab...
Article
Tropical landscapes are changing rapidly as a result of human modifications; however, despite increasing deforestation, human population growth, and the need for more agricultural land, deforestation rates have exceeded the rate at which land is converted to cropland or pasture. For deforested lands to have conservation value requires an understand...
Article
Full-text available
Fruit ripeness can be indicated through changes in chromaticity, luminance, odor, hardness, and size to attract seed dispersing animals. We quantified these attributes for both ripe and unripe fruits of 31 lemur-dispersed plant species in Ankarafantsika National Park, a tropical dry forest in northwestern Madagascar. We used spectroscopy, gas-chrom...
Article
Plant succession theory underpins the development of strategies for the conservation and regeneration of native communities. Current theory has been based largely on space-for-time rather than long-term monitoring data, which have known limitations. There is general consensus that more site-specific studies are needed to corroborate existing hypoth...
Article
Full-text available
Calotropis procera (Ait.) R.Br. (Apocynaceae), an invasive woody milkweed, has expanded its range in northern Australia affecting rangeland and pastoral productivity. While self-compatibility should enhance the species range expansion, spread of C. procera is limited by the availability of larger wasp and bee species that are able to vector its sol...
Article
Full-text available
Seed-dispersal ecology in tropical montane forests (TMF) differs in some predictable ways from tropical lowland forests (TLF). Environmental, biogeographic and biotic factors together shape dispersal syndromes which in turn influence forest structure and community composition. Data on diaspore traits along five elevational gradients from forests in...
Article
Full-text available
Woody plant demographics provide important insight into ecosystem state-shifts in response to changing fire regimes. In Australian tropical savannas, the switch from patchy landscape burning by Aborigines to unmanaged wildfires within the past century has been implicated in biodiversity declines including the fire-sensitive conifer, Callitris intra...
Article
Full-text available
Relative bark thickness (RBT; bark thickness/stem diameter; cm cm−1) is a widely used species-specific plant trait, especially in the context of fire ecology. We consider several problems with its measurement and suggest that (1) it should be measured as bark thickness (BT)/bole diameter and not BT/stem diameter; (2) its measurement should be restr...
Article
Many long-distance migratory shorebirds are threatened. Anthropogenic disturbance at roost sites on their non-breeding grounds might exacerbate other threats by leading to depletion of fat reserves and forcing birds away from traditional sites. We measured the response (occurrence of alarm flight and resettlement time) of roosting shorebirds knots...
Article
Full-text available
Although bark thickness and fire-activity are correlated in many ecosystems worldwide, substantial data-gaps remain, especially for dryland biomes, preventing generalisation of this relationship at the global scale. We examined bark thickness trends in trees and shrubs across a large-scale fire-rainfall gradient from desert to dry savanna in northe...
Article
In this special issue of Plant Ecology celebrating the research contributions of the late Peter J. Clarke, we review advances in understanding of interactions between fire and vegetation, and the role of these interactions in shaping the evolution of plant species. The research presented here reviews the measurement of fire severity and plant respo...
Article
In subtropical coastal dune forests of South Africa, the microenvironment of tree seedlings is largely influenced by a pervasive understorey woody herb, Isoglossa woodii. We examined whether the additional shading by I. woodii explains the competitive response of tree seedlings from these forests. Seedlings of four common mid- to late-successional...
Article
Full-text available
Conservation can be achieved only if sustainability is embraced as core to organizational cultures. To test the extent to which the related concepts of sustainability, conservation, response to climate change, poverty alleviation and gender equity have been incorporated into organizational culture, we compared mission statements in the period 1990–...
Article
Full-text available
The potential spread of any invasive plant is a central concern in weed risk assessment. Calotropis procera is wind dispersed and forms extensive monospecific stands that reduce the productivity of pastoral land, but its potential distribution and drivers of its spread are not well known. Using maximum entropy methodology, we modelled current and f...
Article
Full-text available
s Inter- and intra-specific comparisons were made between several co-occurring populations of two Banksia species growing in Eastern Australian dry sclerophyll open woodland that experiences a grass-fueled surface-fire regime. The two species differ in life-history from a short basal resprouter (B. Neoanglica) to a tall fire-survivor (B. integrifol...
Article
Full-text available
Understanding the seed biology of the introduced weed rubber bush (Calotropis procera (Aiton, W.T.Aiton)) is critical to its management in northern Australia. We examined the numbers of seeds produced and the effects of environmental temperature and water stress on germination performance (germinability G; mean germination time MGT) of rubber bush...
Article
Carbon markets afford potentially useful opportunities for supporting socially and environmentally sustainable land management programs but, to date, have been little applied in globally significant fire-prone savanna settings. While fire is intrinsic to regulating the composition, structure and dynamics of savanna systems, in north Australian sava...
Data
GIS files for Litchfield Landscape Units. (ZIP)
Data
Calculating fire metrics and carbon credits. (DOCX)
Data
GIS files for Kakadu Landscape Units. (ZIP)
Data
GIS files for Nitmiluk Landscape Units. (ZIP)
Data
GIS files for WALFA Landscape Units. (ZIP)
Article
We (Murphy et al., 2013; Clarke et al., 2015) have recently developed a framework to understand the spatial distribution of fire regimes and plant fire-response traits at large spatial scales. We integrated a range of data sources to create a continental-scale overview of Australian pyromes from which to infer pyrogeographic drivers. Gosper et al....
Article
Full-text available
Premise of the study: In fire-prone ecosystems, variation in bark thickness among species and communities has been explained by fire frequency; thick bark is necessary to protect cambium from lethal temperatures. Elsewhere this investment is deemed unnecessary, and thin bark is thought to prevail. However, in rain forest ecosystems where fire is r...
Article
The Eastern Curlew (Numenius madagascariensis) has recently been uplisted to Critically Endangered under Australian Government legislation due to an ongoing decline of the species population on its non-breeding grounds. Declines have been reported from nearly all monitored sites along the coastline of Australia and at some, local extinction is pred...
Article
Full-text available
The high species richness of tropical forests has long been recognized, yet there remains substantial uncertainty regarding the actual number of tropical tree species. Using a pantropical tree inventory database from closed canopy forests, consisting of 657,630 trees belonging to 11,371 species, we use a fitted value of Fisher’s alpha and an approx...
Article
Full-text available
Australia has experienced dramatic declines and extinctions of its native rodent species over the last 200 years, particularly in southern Australia. In the tropical savanna of northern Australia significant declines have occurred only in recent decades. The later onset of these declines suggests that the causes may differ from earlier declines in...
Article
Full-text available
Mangrove habitats are under severe land use pressure throughout the world and Australia is no exception. Here we describe the heterogeneity of mangrove habitat and its relationship with mangrove bird diversity. We examined the role of mangrove habitat complexity in determining the richness of avian mangrove dependent species (MDS) and interior spec...
Article
Full-text available
Plant resprouting after disturbance confers community resilience because individuals persist through trade-offs in resources for buds versus those required to produce seeds. However, repeated disturbance may deplete bud banks, and population persistence may become increasingly reliant on regeneration from seed. Theory predicts a shift in community...
Technical Report
Conflict between Top End livestock producers and high densities of Agile Wallabies (Macropus agilis) on pastoral land has been ongoing for decades. In recent decades wallaby numbers and densities on pastoral lands have increased dramatically. In some agricultural situations wallaby densities are 1000 times greater (>5 animals ha-1) than the natural...
Article
Few measurements for carbon sequestration, ratio of above-ground to below-ground biomass and wood density exist for young trees. Current allometric models are mostly for mature trees, and few consider trees at the sapling stage. Over four years we monitored the growth rates, from seedling to the sapling stage, of 490 trees (five native species) in...
Article
Full-text available
Postfire resprouting and recruitment from seed are key plant life-history traits that influence population dynamics, community composition and ecosystem function. Species can have one or both of these mechanisms. They confer resilience, which may determine community composition through differential species persistence after fire. To predict ecosyst...