- Good, Megan, Schultz, Nick, Tighe, Matthew, Reid, Nick, Briggs, Sue
- Authors: Good, Megan , Schultz, Nick , Tighe, Matthew , Reid, Nick , Briggs, Sue
- Date: 2013
- Type: Text , Journal article
- Relation: Agriculture, Ecosystems & Environment Vol. 179, no. (2013), p. 125-132
- Full Text:
- Reviewed:
- Description: Semi-arid rangelands have strong feedbacks between vegetation and abiotic factors (rainfall and soil), which manifest at the small patch/inter-patch scale. The effects of excluding grazing at the small patch scale have not been studied in these systems, despite fine-grained patch/inter-patch mosaics determining landscape-scale ecosystem function and productivity. We established small (1 m × 1 m) grazing exclosures and monitored change in herbaceous vegetation cover quarterly over 2 years, in grazed and ungrazed patches (high herbaceous vegetation cover) and inter-patches (low herbaceous vegetation cover), in woody encroachment and pasture sites in semi-arid eastern Australia. Prior to excluding grazing, herbaceous groundcover in pasture patches (63–67%) was significantly greater than in woody encroachment patches (15–16%) or inter-patches in both vegetation states (0–1%). The effect of grazing exclusion on herbaceous cover varied between patch type and vegetation state. In the absence of grazing, herbaceous cover was significantly greater in pasture patches than in woody encroachment patches at every monitoring time. Initial differences in herbaceous cover between woody encroachment patches and pasture patches was significantly less pronounced with continued grazing pressure, indicating that grazing pressure can negatively influence the positive effect of a lack of woody plants on herbaceous growth in pastures. Grazed pasture patches had significantly less herbaceous cover than ungrazed pasture patches at every monitoring time, whereas in woody encroachment, grazed patches had less herbaceous cover than ungrazed patches on only two occasions in the second year. Inter-patches in both vegetation states failed to respond to grazing exclusion in the 2-year study period. Herbaceous cover change in semi-arid rangelands is a function of grazing, rainfall and woody plant incidence. If grazing pressure in pasture patches is not carefully managed to maintain herbaceous cover, the positive effects of high rainfall and low woody plant abundance on herbaceous cover can rapidly diminish. Improving herbaceous groundcover overall will require an interventionist approach to overcome barriers to plant establishment in inter-patch areas such as the lack of resource retention.
- Schultz, Nick, Reid, Nick, Lodge, Greg, Hunter, John
- Authors: Schultz, Nick , Reid, Nick , Lodge, Greg , Hunter, John
- Date: 2014
- Type: Text , Journal article
- Relation: Austral Ecology Vol. 39, no. 7 (2014), p. 855-863
- Full Text: false
- Reviewed:
- Description: Plant diversity is threatened in many agricultural landscapes. Our understanding of patterns of plant diversity in these landscapes is mainly based on small-scale (<1000 m2) observations of species richness. However, such observations are insufficient for detecting the spatial heterogeneity of vegetation composition. In a case-study farm on the North-West Slopes of New South Wales, Australia, we observed species richness at four scales (quadrat, patch, land use and landscape) across five land uses (grazed and ungrazed woodlands, native pastures, roadsides and crops). We applied two landscape ecological models to assess the contribution of these land uses to landscape species richness: (i) additive partitioning of diversity at multiple spatial scales, and (ii) a measure of habitat specificity – the effective number of species that a patch contributes to landscape species richness. Native pastures had less variation between patches than grazed and ungrazed woodlands, and hence were less species-rich at the landscape scale, despite having similar richness to woodlands at the quadrat and patch scale. Habitat specificity was significantly higher for ungrazed woodland patches than all other land uses. Our results showed that in this landscape, ungrazed woodland patches had a higher contribution than the grazed land uses to landscape species richness. These results have implications for the conservation management of this landscape, and highlighted the need for greater consensus on the influence of different land uses on landscape patterns of plant diversity.
- Schultz, Nick, Reid, Nick, Lodge, Greg, Hunter, John
- Authors: Schultz, Nick , Reid, Nick , Lodge, Greg , Hunter, John
- Date: 2014
- Type: Text , Journal article
- Relation: Austral Ecology Vol. 39, no. 7 (2014), p. 755-766
- Full Text: false
- Reviewed:
- Description: Understanding how vegetation composition varies with season and interannual climate variability is important for any ecological research that uses vegetation data derived from surveys for the basis of inference. Misunderstanding this variation can influence land management and planning decisions, leading to poor implementation of biodiversity offsetting mechanisms, for example. We monitored plots (400 m2) grazed by livestock paired with adjacent ungrazed plots in derived native pastures four times a year over 2.5 years on the North-West Slopes of New South Wales. Species density in plots varied greatly with season and interannual rainfall. Highest species density was recorded in spring, though species density in summer was not significantly lower, nor was a spring–summer peak in species density evident in the 2009 drought. Surveys in spring 2008 had the highest species density, and recorded only 60–72% of the total species recorded at each site over 2.5 years. Variation in the proportion of total site diversity represented in combinations of two or three surveys was large, though the best combinations comprised surveys from spring and summer in years of above-average rainfall, either from the same spring-summer, or from different years. Compositional differences among sites were much greater than within sites, showing that differences among sites related to broad environmental gradients were not overwhelmed by seasonal and interannual variability in site composition. When grazing was excluded, there was no evidence of competitive exclusion by the dominant grasses, and no directional shift in composition. The implications of these findings for ecological research depend on the question being addressed: if capturing a large proportion of site diversity is important, then surveys must be carefully timed, or repeat surveys must be conducted. Single surveys did not effectively capture site diversity for use in biodiversity offsetting, and the timing of repeat surveys was critical.
Multivariate drivers of diversity in temperate Australian native grasslands
- Price, Jodi, Good, Megan, Schultz, Nick, Guja, Lydia, Morgan, John
- Authors: Price, Jodi , Good, Megan , Schultz, Nick , Guja, Lydia , Morgan, John
- Date: 2019
- Type: Text , Journal article , Review
- Relation: Australian Journal of Botany Vol. 67, no. 5 (2019), p. 367-380
- Full Text: false
- Reviewed:
- Description: Disturbance has been considered essential for maintaining biodiversity in temperate grassy ecosystems in Australia. This has been particularly well demonstrated for inter-tussock plant species in C-4 Themeda-dominated grasslands in mesic environments. Disturbance is also thought crucial to maintain the structure of preferred habitat for some animals. Relationships between disturbance and diversity may be contingent on ecosystem productivity, but little is known about the generality of the disturbance-promoting-diversity paradigm across the range of temperate grasslands. To date, the disturbance-promoting-diversity paradigm has taken a univariate approach to the drivers of biodiversity; rainfall is seen as a key driver of productivity, which then drives diversity, mediated by disturbance. We argue that this framework is too simplistic as biodiversity drivers are multivariate. We suggest that the accumulation of phytomass (live and dead plant material) is an important determinant of diversity in grassy ecosystems and that phytomass accumulation is governed by multiple drivers (of which disturbance is just one). For fauna, it is structure - not biomass - that determines habitat suitability, and this can be moderated by both abiotic and biotic drivers. The assumption that there is a consistent effect of disturbance on diversity through the range of temperate grassland settings in southern Australia ignores the likelihood that biodiversity also responds to other factors such as spatial heterogeneity in the environment, resource availability and climatic variation. We developed a conceptual model of the multivariate drivers of grassland diversity that explores mechanisms underpinning patterns of species richness. Despite four decades of research, it is clear that our understanding of the multivariate drivers of diversity across the range of temperate grasslands in Australia is still incomplete. Further research into the conditions under which disturbance is required to maintain biodiversity in grasslands is integral to conservation planning in these endangered systems.
- Authors: Schultz, Nick , Good, Megan
- Date: 2018
- Type: Text , Journal article
- Relation: Australasian Plant Pathology Vol. 47, no. 4 (2018), p. 393-403
- Full Text: false
- Reviewed:
- Description: Mundulla Yellows is a dieback disorder of trees (predominantly eucalypts) along roadsides in the southeast of South Australia, characterized by interveinal yellowing of leaves and eventual death. There are two main theories about the cause of Mundulla Yellows: (1) that the yellowing is lime chlorosis, caused by crushed limestone dust from roads being washed into soil, and (2) that it is caused by an irreversible and transmissible biotic pathogen. We tested the lime chlorosis hypothesis by inserting nutrients directly into the sapwood of symptomatic trees using systemic nutrient implants. If the lime chlorosis hypothesis is correct, nutrient injections of iron and manganese should increase chlorophyll synthesis and result in leaves becoming greener. We applied four different nutrient combinations (iron, manganese, iron + manganese, and a treatment that included a range of essential plant nutrients), as well as control treatments, to symptomatic trees across 10 sites. After 14 weeks there were significant increases in leaf greenness and crown health, compared to controls, when trees received either iron or iron and manganese implants. The results add further weight to the lime chlorosis hypothesis. Nutrient implants are unlikely to be a viable management strategy due to their cost and potentially short-term benefits, and trees will inevitably be lost from the region’s roadsides. Management options should involve increasing revegetation efforts and natural passive regeneration of trees away from affected roadsides, and revegetating the affected areas with species that are suited to the changed soil conditions.
- Schultz, Nick, Reid, Nick, Lodge, Greg, Hunter, John
- Authors: Schultz, Nick , Reid, Nick , Lodge, Greg , Hunter, John
- Date: 2016
- Type: Text , Journal article
- Relation: Applied Vegetation Science Vol. 19, no. 4 (2016), p. 578-588
- Full Text: false
- Reviewed:
- Description: AimsThe effects of pastoralism on grassy vegetation are predicted to vary across spatial scales. However, local-scale effects have generally been better considered than large-scale effects that may be pertinent for plant diversity conservation. We examined variation in plant diversity in an agricultural region by comparing patterns observed at large and local scales for different land uses. We tested whether habitat specificity (which relates to how specific different species are to particular land uses) can indicate the importance of land uses to plant diversity conservation. MethodsWe surveyed 127 quadrats of grassy vegetation across four land uses: previously cultivated and never-cultivated native pastures, grazed woodland and ungrazed woodlands (grazing refugia). We assessed (1) species density at the quadrat scale, (2) correlations among explanatory variables and species composition using ordination techniques, and (3) habitat specificity at the regional scale using the -diversity contribution index. ResultsAt the quadrat scale, differences in species density among land uses were not pronounced. In contrast, habitat specificity was highest in ungrazed, unfertilized woodlands. Land uses that were grazed, cleared of trees and fertilized were generally species dense at the quadrat scale (>40 species 400m(-2)), but were comprised of a limited suite of native and exotic grasses and forbs, with relatively homogeneous composition across the region. ConclusionsIn the region studied, grazing refugia with no tree clearing or history of fertilizer application were valuable for conserving a large number of native species, and so should be protected. Such land uses are currently rare in the region. Simple measures of native or total species density were insufficient for evaluating conservation value, as they did not distinguish habitats with large numbers of common, generalist native species from those with species that were rare or restricted in the region. Analyses of habitat specificity may potentially overcome the pitfalls of basing conservation management decisions on local-scale measures. Our results also highlighted a need to understand the processes associated with management practices that serve to reduce species diversity at landscape and regional scales.
The golf ball method for rapid assessment of grassland structure
- Schultz, Nick, Keatley, Marie, Antos, Mark, Wong, Nathan, Moxham, Claire, Farmilo, Brad, Morgan, John
- Authors: Schultz, Nick , Keatley, Marie , Antos, Mark , Wong, Nathan , Moxham, Claire , Farmilo, Brad , Morgan, John
- Date: 2017
- Type: Text , Journal article
- Relation: Ecological Management and Restoration Vol. 18, no. 2 (2017), p. 134-140
- Full Text: false
- Reviewed:
- Description: A key task for native grassland managers is to assess when biomass reduction is necessary to maintain plant and animal diversity. This requires managers to monitor grassland structure. Parks Victoria and La Trobe University developed a method for rapid assessment of grassland structure using golf balls. Baker-Gabb et al. (Ecological Management & Restoration, 17, 2016, p235) provide an example of where the method has been used to manage grassland structure to favour an endangered bird, the Plains-wanderer (Pedionomus torquatus). In this study, we provide further critical analysis of the method using three data sets collected across different parts of Victoria that relate golf ball scores to various habitat attributes. We demonstrate how the golf ball score provides a good surrogate for key aspects of grassland structure. We show that the method does not provide a reliable surrogate for above-ground biomass or vegetation cover, although we discuss how biomass and cover are not particularly good indicators of grassland structure. We argue that elements of grassland structure may be better correlated with desired conservation outcomes (e.g. plant species diversity or the presence of a particular species) than biomass or cover alone. We discuss examples of how the golf ball method has been used, and how it can be improved. The method will be particularly useful where a link can be demonstrated between golf ball scores and desired conservation outcomes, such as in the case of the Plains-wanderer. © 2017 Ecological Society of Australia and John Wiley & Sons Australia, Ltd
- Schultz, Nick, Morgan, John, Lunt, Ian
- Authors: Schultz, Nick , Morgan, John , Lunt, Ian
- Date: 2011
- Type: Text , Journal article
- Relation: Journal of Vegetation Science Vol. 22, no. 1 (2011), p. 130-142
- Full Text: false
- Reviewed:
- Description: Question: Does long-term grazing exclusion affect plant species diversity? And does this effect vary with long-term phytomass accumulation across a regional productivity gradient? Location: Lowland grassy ecosystems across the state of Victoria, southeast Australia. Methods: Floristic surveys and phytomass sampling were conducted across a broad-scale productivity gradient in grazing exclusion plots and adjacent grazed areas. Differences in species richness, evenness and life-form evenness between grazed and ungrazed areas were analysed. The environmental drivers of long-term phytomass accumulation were assessed using multiple linear regression analysis. Results: Species richness declined in the absence of grazing only at the high productivity sites (i.e. when phytomass accumulation was >500 gm-2). Species evenness and life-form evenness also showed a negative relationship with increasing phytomass accumulation. Phytomass accumulation was positively associated with both soil nitrogen and rainfall, and negatively associated with tree cover. Conclusions: Competitive dominance is a key factor regulating plant diversity in productive grassy ecosystems, but canopy disturbance is not likely to be necessary to maintain diversity in less productive systems. The results support the predictions of models of the effects of grazing on plant diversity, such as the dynamic equilibrium model, whereby the effects of herbivory are context-dependent and vary according to gradients of rainfall, soil fertility and tree cover. © 2010 International Association for Vegetation Science.
Lower dormancy with rapid germination is an important strategy for seeds in an arid zone with unpredictable rainfall
- Duncan, Corrine, Schultz, Nick, Lewandrowski, Wolfgang, Good, Megan, Cook, Simon
- Authors: Duncan, Corrine , Schultz, Nick , Lewandrowski, Wolfgang , Good, Megan , Cook, Simon
- Date: 2019
- Type: Text , Journal article
- Relation: PLoS ONE Vol. 14, no. 9 (2019), p.
- Full Text:
- Reviewed:
- Description: Seed germination traits are key drivers of population dynamics, yet they are under-represented in community ecology studies, which have predominately focussed on adult plant and seed morphological traits. We studied the seed traits and germination strategy of eight woody plant species to investigate regeneration strategies in the arid zone of eastern Australia. To cope with stochastic and minimal rainfall, we predict that arid seeds will either have rapid germination across a wide range of temperatures, improved germination under cooler temperatures, or dormancy and/or longevity traits to delay or stagger germination across time. To understand how temperature affects germination responses, seeds of eight keystone arid species were germinated under laboratory conditions, and under three diurnal temperatures (30/20°C, 25/15°C and 17/7°C) for 30 days. We also tested for decline in seed viability across 24 months in a dry-aging treatment (
- Authors: Duncan, Corrine , Schultz, Nick , Lewandrowski, Wolfgang , Good, Megan , Cook, Simon
- Date: 2019
- Type: Text , Journal article
- Relation: PLoS ONE Vol. 14, no. 9 (2019), p.
- Full Text:
- Reviewed:
- Description: Seed germination traits are key drivers of population dynamics, yet they are under-represented in community ecology studies, which have predominately focussed on adult plant and seed morphological traits. We studied the seed traits and germination strategy of eight woody plant species to investigate regeneration strategies in the arid zone of eastern Australia. To cope with stochastic and minimal rainfall, we predict that arid seeds will either have rapid germination across a wide range of temperatures, improved germination under cooler temperatures, or dormancy and/or longevity traits to delay or stagger germination across time. To understand how temperature affects germination responses, seeds of eight keystone arid species were germinated under laboratory conditions, and under three diurnal temperatures (30/20°C, 25/15°C and 17/7°C) for 30 days. We also tested for decline in seed viability across 24 months in a dry-aging treatment (
- Authors: Antos, Mark , Schultz, Nick
- Date: 2020
- Type: Text , Journal article
- Relation: Emu Vol. 120, no. 1 (2020), p. 2-10
- Full Text: false
- Reviewed:
- Description: The critically endangered and iconic plains-wanderer (Pedionomus torquatus) is phylogenetically distinct and endemic to south eastern Australia, and is a high conservation priority. Furthermore, it relies on critically-endangered native grasslands for its survival, which vary temporally in structure and hence do not always provide suitable habitat. To manage the remaining native grasslands appropriately, it is essential to understand the temporal and spatial dynamics of plains-wanderer habitat preferences. We monitored plains-wanderers and habitat measurements for nine years to link habitat preferences to specific elements of grassland structure. We also observed habitat selection by plains-wanderers at two spatial scales–sites (paddocks) and at microsites (immediate vicinity of the birds). The plains-wanderer population declined rapidly after a dramatic increase in native grass cover in 2011, and recovery of the population since then has been slow. In 2015/16, plains-wanderers were generally encountered at microsites with higher bare ground and cryptogam cover. However, at the site scale, paddocks with plains-wanderers had similar cover of native grass and bare ground than those without plains-wanderers. The results suggest that observation of highly-localised habitat components alone may mask aspects of the habitat selection occurring at larger spatial scales. Plains-wanderers may require areas of denser perennial grass for nesting and shelter, as well as access to the open areas where they are commonly encountered. We discuss how private land used for commercial grazing may be crucial to plains-wanderer conservation. The results also prompt consideration of how we measure and interpret habitat selection for grassland birds globally. © 2019, © 2019 BirdLife Australia.
The risk-takers and -avoiders : germination sensitivity to water stress in an arid zone with unpredictable rainfall
- Duncan, Corrine, Schultz, Nick, Good, Megan, Lewandrowski, Wolfgang, Cook, Simon
- Authors: Duncan, Corrine , Schultz, Nick , Good, Megan , Lewandrowski, Wolfgang , Cook, Simon
- Date: 2019
- Type: Text , Journal article
- Relation: AoB PLANTS Vol. 11, no. 6 (2019), p.
- Full Text:
- Reviewed:
- Description: Water availability is a critical driver of population dynamics in arid zones, and plant recruitment is typically episodic in response to rainfall. Understanding species' germination thresholds is key for conservation and restoration initiatives. Thus, we investigated the role of water availability in the germination traits of keystone species in an arid ecosystem with stochastic rainfall. We measured seed germination responses of five arid species, along gradients of temperature and water potential under controlled laboratory conditions. We then identified the cardinal temperatures and base water potentials for seed germination, and applied the hydrotime model to assess germination responses to water stress. Optimum temperatures for germination ranged from 15 to 31 °C under saturated conditions (0 MPa), and three species had low minimum temperatures for germination (<3 °C). A small proportion of seeds of all species germinated under dry conditions (ψ ≤ -1 MPa), although base water potential for germination (ψb50) ranged from -0.61 to -0.79 MPa. Species adhered to one of two germination traits: (i) the risk-takers which require less moisture availability for germination, and which can germinate over a wider range of temperatures irrespective of water availability (Casuarina pauper and Maireana pyramidata), and (ii) the risk-avoiders which have greater moisture requirements, a preference for cold climate germination, and narrower temperature ranges for germination when water availability is low (Atriplex rhagodioides, Maireana sedifolia and Hakea leucoptera). High seed longevity under physiological stress in H. leucoptera, combined with a risk-avoiding strategy, allows bet-hedging. The hydrotime model predicted lower base water potentials for germination than observed by the data, further supporting our assertion that these species have particular adaptations to avoid germination during drought. This study provides insights into the complex physiological responses of seeds to environmental stress, and relates seed germination traits to community dynamics and restoration in arid zones. © 2019 The Author(s) 2019. Published by Oxford University Press on behalf of the Annals of Botany Company.
- Authors: Duncan, Corrine , Schultz, Nick , Good, Megan , Lewandrowski, Wolfgang , Cook, Simon
- Date: 2019
- Type: Text , Journal article
- Relation: AoB PLANTS Vol. 11, no. 6 (2019), p.
- Full Text:
- Reviewed:
- Description: Water availability is a critical driver of population dynamics in arid zones, and plant recruitment is typically episodic in response to rainfall. Understanding species' germination thresholds is key for conservation and restoration initiatives. Thus, we investigated the role of water availability in the germination traits of keystone species in an arid ecosystem with stochastic rainfall. We measured seed germination responses of five arid species, along gradients of temperature and water potential under controlled laboratory conditions. We then identified the cardinal temperatures and base water potentials for seed germination, and applied the hydrotime model to assess germination responses to water stress. Optimum temperatures for germination ranged from 15 to 31 °C under saturated conditions (0 MPa), and three species had low minimum temperatures for germination (<3 °C). A small proportion of seeds of all species germinated under dry conditions (ψ ≤ -1 MPa), although base water potential for germination (ψb50) ranged from -0.61 to -0.79 MPa. Species adhered to one of two germination traits: (i) the risk-takers which require less moisture availability for germination, and which can germinate over a wider range of temperatures irrespective of water availability (Casuarina pauper and Maireana pyramidata), and (ii) the risk-avoiders which have greater moisture requirements, a preference for cold climate germination, and narrower temperature ranges for germination when water availability is low (Atriplex rhagodioides, Maireana sedifolia and Hakea leucoptera). High seed longevity under physiological stress in H. leucoptera, combined with a risk-avoiding strategy, allows bet-hedging. The hydrotime model predicted lower base water potentials for germination than observed by the data, further supporting our assertion that these species have particular adaptations to avoid germination during drought. This study provides insights into the complex physiological responses of seeds to environmental stress, and relates seed germination traits to community dynamics and restoration in arid zones. © 2019 The Author(s) 2019. Published by Oxford University Press on behalf of the Annals of Botany Company.
Change in dominance determines herbivore effects on plant biodiversity
- Koerner, Sally, Smith, Melinda, Burkepile, Deron, Hanan, Niall, Avolio, Meghan, Collins, Scott, Knapp, Alan, Lemoine, Nathan, Forrestel, Elizabeth, Eby, Stephanie, Thompson, Dave, Aguado-Santacruz, Gerardo, Anderson, John, Anderson, Michael, Angassa, Ayana, Bagchi, Sumanta, Bakker, Elisabeth, Bastin, Gary, Baur, Lauren, Beard, Karen, Beever, Erik, Bohlen, Patrick, Boughton, Elizabeth, Canestro, Don, Cesa, Ariela, Chaneton, Enrique, Cheng, Jimin, D'Antonio, Carla, Deleglise, Claire, Dembele, Fadiala, Dorrough, Josh, Eldridge, David, Fernandez-Going, Barbara, Fernandez-Lugo, Silvia, Fraser, Lauchlan, Freedman, Bill, Garcia-Salgado, Gonzalo, Goheen, Jacob, Guo, Liang, Husheer, Sean, Karembe, Moussa, Knops, Johannes, Kraaij, Tineke, Kulmatiski, Andrew, Kytoviita, Minna-Maarit, Lezama, Felipe, Loucougaray, Gregory, Loydi, Alejandro, Milchunas, Dan, Milton, Suzanne, Morgan, John, Moxham, Claire, Nehring, Kyle, Olff, Han, Palmer, Todd, Rebollo, Salvador, Riginos, Corinna, Risch, Anita, Rueda, Marta, Sankaran, Mahesh, Sasaki, Takehiro, Schoenecker, Kathryn, Schultz, Nick, Schutz, Martin, Schwabe, Angelika, Siebert, Frances, Smit, Christian, Stahlheber, Karen, Storm, Christian, Strong, Dustin, Su, Jishuai, Tiruvaimozhi, Yadugiri, Tyler, Claudia, Val, James, Vandegehuchte, Martijn, Veblen, Kari, Vermeire, Lance, Ward, David, Wu, Jianshuang, Young, Truman, Yu, Qiang, Zelikova, Tamara
- Authors: Koerner, Sally , Smith, Melinda , Burkepile, Deron , Hanan, Niall , Avolio, Meghan , Collins, Scott , Knapp, Alan , Lemoine, Nathan , Forrestel, Elizabeth , Eby, Stephanie , Thompson, Dave , Aguado-Santacruz, Gerardo , Anderson, John , Anderson, Michael , Angassa, Ayana , Bagchi, Sumanta , Bakker, Elisabeth , Bastin, Gary , Baur, Lauren , Beard, Karen , Beever, Erik , Bohlen, Patrick , Boughton, Elizabeth , Canestro, Don , Cesa, Ariela , Chaneton, Enrique , Cheng, Jimin , D'Antonio, Carla , Deleglise, Claire , Dembele, Fadiala , Dorrough, Josh , Eldridge, David , Fernandez-Going, Barbara , Fernandez-Lugo, Silvia , Fraser, Lauchlan , Freedman, Bill , Garcia-Salgado, Gonzalo , Goheen, Jacob , Guo, Liang , Husheer, Sean , Karembe, Moussa , Knops, Johannes , Kraaij, Tineke , Kulmatiski, Andrew , Kytoviita, Minna-Maarit , Lezama, Felipe , Loucougaray, Gregory , Loydi, Alejandro , Milchunas, Dan , Milton, Suzanne , Morgan, John , Moxham, Claire , Nehring, Kyle , Olff, Han , Palmer, Todd , Rebollo, Salvador , Riginos, Corinna , Risch, Anita , Rueda, Marta , Sankaran, Mahesh , Sasaki, Takehiro , Schoenecker, Kathryn , Schultz, Nick , Schutz, Martin , Schwabe, Angelika , Siebert, Frances , Smit, Christian , Stahlheber, Karen , Storm, Christian , Strong, Dustin , Su, Jishuai , Tiruvaimozhi, Yadugiri , Tyler, Claudia , Val, James , Vandegehuchte, Martijn , Veblen, Kari , Vermeire, Lance , Ward, David , Wu, Jianshuang , Young, Truman , Yu, Qiang , Zelikova, Tamara
- Date: 2018
- Type: Text , Journal article
- Relation: Nature Ecology & Evolution Vol. 2, no. 12 (2018), p. 1925-1932
- Full Text:
- Reviewed:
- Description: Herbivores alter plant biodiversity (species richness) in many of the world’s ecosystems, but the magnitude and the direction of herbivore effects on biodiversity vary widely within and among ecosystems. One current theory predicts that herbivores enhance plant biodiversity at high productivity but have the opposite effect at low productivity. Yet, empirical support for the importance of site productivity as a mediator of these herbivore impacts is equivocal. Here, we synthesize data from 252 large-herbivore exclusion studies, spanning a 20-fold range in site productivity, to test an alternative hypothesis—that herbivore-induced changes in the competitive environment determine the response of plant biodiversity to herbivory irrespective of productivity. Under this hypothesis, when herbivores reduce the abundance (biomass, cover) of dominant species (for example, because the dominant plant is palatable), additional resources become available to support new species, thereby increasing biodiversity. By contrast, if herbivores promote high dominance by increasing the abundance of herbivory-resistant, unpalatable species, then resource availability for other species decreases reducing biodiversity. We show that herbivore-induced change in dominance, independent of site productivity or precipitation (a proxy for productivity), is the best predictor of herbivore effects on biodiversity in grassland and savannah sites. Given that most herbaceous ecosystems are dominated by one or a few species, altering the competitive environment via herbivores or by other means may be an effective strategy for conserving biodiversity in grasslands and savannahs globally.
- Authors: Koerner, Sally , Smith, Melinda , Burkepile, Deron , Hanan, Niall , Avolio, Meghan , Collins, Scott , Knapp, Alan , Lemoine, Nathan , Forrestel, Elizabeth , Eby, Stephanie , Thompson, Dave , Aguado-Santacruz, Gerardo , Anderson, John , Anderson, Michael , Angassa, Ayana , Bagchi, Sumanta , Bakker, Elisabeth , Bastin, Gary , Baur, Lauren , Beard, Karen , Beever, Erik , Bohlen, Patrick , Boughton, Elizabeth , Canestro, Don , Cesa, Ariela , Chaneton, Enrique , Cheng, Jimin , D'Antonio, Carla , Deleglise, Claire , Dembele, Fadiala , Dorrough, Josh , Eldridge, David , Fernandez-Going, Barbara , Fernandez-Lugo, Silvia , Fraser, Lauchlan , Freedman, Bill , Garcia-Salgado, Gonzalo , Goheen, Jacob , Guo, Liang , Husheer, Sean , Karembe, Moussa , Knops, Johannes , Kraaij, Tineke , Kulmatiski, Andrew , Kytoviita, Minna-Maarit , Lezama, Felipe , Loucougaray, Gregory , Loydi, Alejandro , Milchunas, Dan , Milton, Suzanne , Morgan, John , Moxham, Claire , Nehring, Kyle , Olff, Han , Palmer, Todd , Rebollo, Salvador , Riginos, Corinna , Risch, Anita , Rueda, Marta , Sankaran, Mahesh , Sasaki, Takehiro , Schoenecker, Kathryn , Schultz, Nick , Schutz, Martin , Schwabe, Angelika , Siebert, Frances , Smit, Christian , Stahlheber, Karen , Storm, Christian , Strong, Dustin , Su, Jishuai , Tiruvaimozhi, Yadugiri , Tyler, Claudia , Val, James , Vandegehuchte, Martijn , Veblen, Kari , Vermeire, Lance , Ward, David , Wu, Jianshuang , Young, Truman , Yu, Qiang , Zelikova, Tamara
- Date: 2018
- Type: Text , Journal article
- Relation: Nature Ecology & Evolution Vol. 2, no. 12 (2018), p. 1925-1932
- Full Text:
- Reviewed:
- Description: Herbivores alter plant biodiversity (species richness) in many of the world’s ecosystems, but the magnitude and the direction of herbivore effects on biodiversity vary widely within and among ecosystems. One current theory predicts that herbivores enhance plant biodiversity at high productivity but have the opposite effect at low productivity. Yet, empirical support for the importance of site productivity as a mediator of these herbivore impacts is equivocal. Here, we synthesize data from 252 large-herbivore exclusion studies, spanning a 20-fold range in site productivity, to test an alternative hypothesis—that herbivore-induced changes in the competitive environment determine the response of plant biodiversity to herbivory irrespective of productivity. Under this hypothesis, when herbivores reduce the abundance (biomass, cover) of dominant species (for example, because the dominant plant is palatable), additional resources become available to support new species, thereby increasing biodiversity. By contrast, if herbivores promote high dominance by increasing the abundance of herbivory-resistant, unpalatable species, then resource availability for other species decreases reducing biodiversity. We show that herbivore-induced change in dominance, independent of site productivity or precipitation (a proxy for productivity), is the best predictor of herbivore effects on biodiversity in grassland and savannah sites. Given that most herbaceous ecosystems are dominated by one or a few species, altering the competitive environment via herbivores or by other means may be an effective strategy for conserving biodiversity in grasslands and savannahs globally.
Soil reconstruction after mining fails to restore soil function in an Australian arid woodland
- Duncan, Corrine, Good, Megan, Sluiter, Ian, Cook, Simon, Schultz, Nick
- Authors: Duncan, Corrine , Good, Megan , Sluiter, Ian , Cook, Simon , Schultz, Nick
- Date: 2020
- Type: Text , Journal article
- Relation: Restoration Ecology Vol. 28, no. S1 (2020), p. A35-A43
- Full Text:
- Reviewed:
- Description: The biogeochemical properties of soils drive ecosystem function and vegetation dynamics, and hence soil restoration after mining should aim to reinstate the soil properties and hydrological dynamics of remnant ecosystems. The aim of this study is to assess soil structure in two vegetation types in an arid ecosystem, and to understand how these soil properties compare to a reconstructed soil profile after mining. In an arid ecosystem in southeast Australia, soil samples were collected at five depths (to 105 cm) from remnant woodland and shrubland sites, and sites either disturbed or totally reconstructed after mining. We assessed soil physico-chemical properties and microbial activity. Soils in the remnant arid ecosystem had coarse-textured topsoils that overlay clay horizons, which allows water to infiltrate and avoid evaporation, but also slows drainage to deeper horizons. Conversely, reconstructed soils had high sand content at subsoil horizons and high bulk density and compaction at surface layers (0–20 cm). Reconstructed soils had topsoils with higher pH and electrical conductivity. The reconstructed soils did not show increased microbial activity with time since restoration. Overall, the reconstructed soil horizons were not organized in a way that allowed rainfall infiltration and water storage, as is imperative to arid-zone ecosystem function. Future restoration efforts in arid ecosystems should focus on increasing sand content of soils near the surface, to reduce evaporative water loss and improve soil quality and plant health. © 2020 Society for Ecological Restoration
- Authors: Duncan, Corrine , Good, Megan , Sluiter, Ian , Cook, Simon , Schultz, Nick
- Date: 2020
- Type: Text , Journal article
- Relation: Restoration Ecology Vol. 28, no. S1 (2020), p. A35-A43
- Full Text:
- Reviewed:
- Description: The biogeochemical properties of soils drive ecosystem function and vegetation dynamics, and hence soil restoration after mining should aim to reinstate the soil properties and hydrological dynamics of remnant ecosystems. The aim of this study is to assess soil structure in two vegetation types in an arid ecosystem, and to understand how these soil properties compare to a reconstructed soil profile after mining. In an arid ecosystem in southeast Australia, soil samples were collected at five depths (to 105 cm) from remnant woodland and shrubland sites, and sites either disturbed or totally reconstructed after mining. We assessed soil physico-chemical properties and microbial activity. Soils in the remnant arid ecosystem had coarse-textured topsoils that overlay clay horizons, which allows water to infiltrate and avoid evaporation, but also slows drainage to deeper horizons. Conversely, reconstructed soils had high sand content at subsoil horizons and high bulk density and compaction at surface layers (0–20 cm). Reconstructed soils had topsoils with higher pH and electrical conductivity. The reconstructed soils did not show increased microbial activity with time since restoration. Overall, the reconstructed soil horizons were not organized in a way that allowed rainfall infiltration and water storage, as is imperative to arid-zone ecosystem function. Future restoration efforts in arid ecosystems should focus on increasing sand content of soils near the surface, to reduce evaporative water loss and improve soil quality and plant health. © 2020 Society for Ecological Restoration
- Sluiter, Ian, Holdgate, Guy, Reichgelt, Tammo, Greenwood, David, Kershaw, A. P., Schultz, Nick
- Authors: Sluiter, Ian , Holdgate, Guy , Reichgelt, Tammo , Greenwood, David , Kershaw, A. P. , Schultz, Nick
- Date: 2022
- Type: Text , Journal article
- Relation: Palaeogeography, Palaeoclimatology, Palaeoecology Vol. 596, no. (2022), p.
- Full Text: false
- Reviewed:
- Description: We present a composite terrestrial pollen record of latest Eocene through Oligocene (35.5–23 Ma) vegetation and climate change from the Gippsland Basin of south-eastern Australia. Climates were overwhelmingly mesothermic through this time period, with mean annual temperature (MAT) varying between 13 and 18 °C, with an average of 16 °C. We provide evidence to support a cooling trend through the Eocene–Oligocene Transition (EOT), but also identify three subsequent warming cycles through the Oligocene, leading to more seasonal climates at the termination of the Epoch. One of the warming episodes in the Early Oligocene appears to have also occurred at two other southern hemisphere sites at the Drake Passage as well as off eastern Tasmania, based on recent research. Similarities with sea surface temperature records from modern high southern latitudes which also record similar cycles of warming and cooling, are presented and discussed. Annual precipitation varied between 1200 and 1700 mm/yr, with an average of 1470 mm/yr through the sequence. Notwithstanding the extinction of Nothofagus sg. Brassospora from Australia and some now microthermic humid restricted Podocarpaceae conifer taxa, the rainforest vegetation of lowland south-eastern Australia is reconstructed to have been similar to present day Australian Evergreen Notophyll Vine Forests existing under the sub-tropical Köppen-Geiger climate class Cfa (humid subtropical) for most of the sequence. Short periods of cooler climates, such as occurred through the EOT when MAT was ~ 13 °C, may have supported vegetation similar to modern day Evergreen Microphyll Fern Forest. Of potentially greater significance, however, was a warm period in the Early to early Late Oligocene (32–26 Ma) when MAT was 17–18 °C, accompanied by small but important increases in Araucariaceae pollen. At this time, Araucarian Notophyll/Microphyll Vine Forest likely occurred regionally. © 2022 Elsevier B.V.
- «
- ‹
- 1
- ›
- »