Offspring size plasticity in response to intraspecific competition: An adaptive maternal effect across life-history stages

When provisioning offspring, mothers balance the benefits of producing a few large, fitter offspring with the costs of decreased fecundity. The optimal balance between offspring size and fecundity depends on the environment. Theory predicts that larger offspring have advantages in adverse conditions, but in favorable conditions size is less important. Thus, if environmental quality varies, selection should favor mothers that adaptively allocate resources in response to local conditions to maximize maternal fitness. In the bryozoan Bugula neritina, we show that the intensity of intraspecific competition dramatically changes the offspring size/performance relationship in the field. In benign or extremely competitive environments, offspring size is less important, but at intermediate levels of competition, colonies from larger larvae have higher performance than colonies from smaller larvae. We predicted mothers should produce larger offspring when intermediate competition is likely and tested these expectations in the field by manipulating the density of brood colonies. Our findings matched expectations: mothers produced larger larvae at high densities and smaller larvae at low densities. In addition, mothers from high‐density environments produced larvae that have higher dispersal potential, which may enable offspring to escape crowded environments. It appears mothers can adaptively adjust offspring size to maximize maternal fitness, altering the offspring phenotype across multiple life‐history stages

Demography and Management of the Invasive Plant Species Hypericum perforatum. II. Construction and Use of an Individual-Based Model to Predict Population Dynamics and the Effects of Management Strategies

1. Hypericum perforatum , St John's wort, is an invasive weed of natural and agro-ecosystems in south-eastern Australia. In previous work we used a long-term data set to determine which plant traits and environmental factors influence population growth and persistence in this species. These results were then used to parameterize an individual-based model of the population dynamics of H. perforatum , and this model was used to make predictions about what control strategies will be most effective for populations in open and shaded sites. 2. The model was constructed using multi-level, mixed-effects statistical models of growth, survival, fecundity and damage, incorporating intrinsic plant variables, environmental variables, herbivory and spatial and temporal stochasticity. 3. We found that populations in shaded and open sites had different dynamics and responses to control strategies. Shaded populations took longer to reach infestation densities and were less affected by herbivory and reductions in survival than open populations. Open populations increased faster in response to increases in rainfall, but this was not so for shaded populations. 4. We used sensitivity testing and management simulations to predict that the most successful control strategies will involve a reduction in vegetative size in both open and shaded sites. Reductions in flowering stem size and survival in shaded and open sites, respectively, are predicted to be the next most successful strategies. Dry conditions in the austral autumn/winter adversely affect populations in both open and shaded sites. 5. Synthesis and applications . These models have enabled us to rank management strategies based on quantitative analysis of their potential effects on population size. This is an important tool not only for ecologists concerned with control of invasive species but for conservation biologists trying to understand the factors limiting a rare or endangered species

Demography and Management of the Invasive Plant Species Hypericum perforatum. I. Using Multi-Level Mixed-Effects Models For Characterizing Growth, Survival and Fecundity in a Long-Term Data Set

1. Hypericum perforatum , St John's wort, is an invasive perennial herb that is especially problematic on waste ground, roadsides, pastures and open woodland in south-eastern Australia. We use detailed data from a long-term observational study to develop quantitative models of the factors affecting growth, survival and fecundity of H. perforatum individuals. 2. Multi-level or hierarchical mixed-effects statistical models are used to analyse how environmental and intrinsic plant variables affect growth and reproduction within a complex nested spatial and temporal context. These techniques are relatively underused in ecology, despite the prevalence of multi-level and repeated-measures data generated from ecological studies. 3. We found that plant size (rosette or flowering stems) was strongly correlated with all life stages studied (growth, probability of flowering, asexual reproduction, survival and fruit production). Environmental variables such as herbivory, ground cover and rainfall had significant effects on several life stages. 4. Significant spatial variation at the quadrat level was found in the probability of flowering, flowering stem growth and fruit production models; variation at all other spatial levels in all models was non-significant. Yearly temporal variation was significant in all models where multi-year data were available. 5. Plants in shaded habitats were smaller but had higher survival probabilities than plants in open habitats. They are therefore likely to have slightly different population dynamics. 6. Synthesis and applications. Analysis of these models for H. perforatum has provided insights into which plant traits and environmental factors determine how populations increase and persist in exotic ecosystems, enabling population management strategies to be most effectively targeted. Spatially and temporally correlated data are often collected in long-term ecological studies and multi-level models are a way in which we can fully exploit the wealth of data available. Without these tools data are either underexploited or crucial assumptions of independence on which many statistics are based are contravene

Modelling Integrated Weed Management of an Invasive Shrub in Tropical Australia

1. Most invasive plant species are not well controlled and where biocontrol programs are in place only one third are fully successful. Integrated weed management (IWM) emphasises the use of several complementary control measures. Choosing which combinations will yield control and how biocontrol fits within the strategy requires detailed knowledge of the dynamics of the target and its ecosystem. 2. We used models of increasing complexity to determine which parameters affect site occupancy of an invasive shrub, Mimosa pigra L. in tropical Australia. Two introduced biocontrol agents have spatial effects on both plant fecundity and the probability of recolonisation after senescence. We incorporated biocontrol effects into IWM models with disturbance, mechanical control, herbicide and fire. The models were parameterised from experimental and field data. 3. Models indicate that the reduction in fecundity is not the most important impact of biocontrol; rather it is through defoliation at the edges of stands allowing grasses to out-compete M. pigra seedlings. We demonstrate that biocontrol alone is only successful at low disturbance and seedling survival and even then, current biocontrol agents would take decades to reduce a stand t

Patterns of introduced species interactions affect multiple aspects of network structure in plant-pollinator communities

Species introductions have the potential to affect the functionality and stability of ecological communities, but because little is known about how introduced species form novel interactions, these impacts are difficult to predict. We quantified the impacts of species introductions on species interaction networks using five different model scenarios of how a novel species might form plant–pollinator interactions. The network structure was based on experimental manipulations on a community of plants and pollinators and shows that the community was more diverse, ordered, and compartmentalized, but less complex when an invasive plant generalist was present. Our models of species introductions reliably predicted several aspects of novel network structure in the field study. We found that introduced species that become incorporated into the community as generalists (both in the number and frequency of their interactions) have a much larger impact on the structure of plant–pollinator communities than introduced species that integrate into the community with few interactions. Average degree is strongly affected by the number of interactions the novel species forms and whether it competes for interactions, whereas connectance is affected by whether the novel species competes for interactions or adds new interaction partners. The number and size of compartments in the network change only when the novel species adds new interaction partners, while modularity and nestedness respond most to the number of interactions formed by the novel species. We provide a new approach for understanding the impacts of introduced and invasive species on plant–pollinator communities and demonstrate that it is critical to evaluate multiple structural characters simultaneously, as large changes in the fundamental structure of the community may be disguised

Dispersal capacity predicts both population genetic structure and species richness in reef fishes

Dispersal is a fundamental species characteristic that should directly affect both rates of gene flow among spatially distributed populations and opportunities for speciation. Yet no single trait associated with dispersal has been demonstrated to affect both micro- and macroevolutionary patterns of diversity across a diverse biological assemblage. Here, we examine patterns of genetic differentiation and species richness in reef fishes, an assemblage of over 7,000 species comprising approximately one-third of the extant bony fishes and over one-tenth of living vertebrates. In reef fishes, dispersal occurs primarily during a planktonic larval stage. There are two major reproductive and parental investment syndromes among reef fishes, and the differences between them have implications for dispersal: (1) benthic guarding fishes lay negatively buoyant eggs, typically guarded by the male parent, and from these eggs hatch large, strongly swimming larvae; in contrast, (2) pelagic spawning fishes release small floating eggs directly into the water column, which drift unprotected before small weakly swimming larvae hatch. Using phylogenetic comparative methods, we show that benthic guarders have significantly greater population structure than pelagic spawners and additionally that taxonomic families of benthic guarders are more species rich than families of pelagic spawners. Our findings provide a compelling case for the continuity between micro- and macroevolutionary processes of biological diversification and underscore the importance of dispersalrelated traits in influencing the mode and tempo of evolution

Agricultural legacy, climate, and soil influence the restoration and carbon potential of woody regrowth in Australia

Opportunities for dual restoration and carbon benefits from naturally regenerating woody ecosystems in agricultural landscapes have been highlighted recently. The restoration capacity of woody ecosystems depends on the magnitude and duration of ecosystem modification, i.e., the ''agricultural legacy.'' However, this legacy may not influence carbon sequestration in the same way as restoration because carbon potential depends primarily on biomass accumulation, with little consideration of other attributes and functions of the ecosystem. Our present study simultaneously assesses the restoration and carbon potential of Acacia harpophylla regrowth, an extensive regrowth ecosystem in northeastern Australia. We used a landscape-scale survey of A. harpophylla regrowth to test the following hypotheses: (1) management history, in combination with climatic and edaphic factors, has long-term effects on stem densities, and (2) higher-density stands have lower restoration and carbon potential, which is also influenced by climatic and edaphic factors. We focused on the restoration of forest structure, which was characterized using stem density, aboveground biomass, stem heights, and stem diameters. Data were analyzed using multilevel models within the hierarchical Bayesian model (HBM) framework. We found strong support for both hypotheses. Repeated attempts at clearing Brigalow (A. harpophylla ecosystem) regrowth increases stem densities, and these densities remain high over the long term, particularly in high-rainfall areas and on gilgaied, high-clay soils (hypothesis 1). In models testing hypothesis 2, interactions between stem density and stand age indicate that higher-density stands have slower biomass accumulation and structural development in the long term. After accounting for stem density and stand age, annual rainfall had a positive effect on biomass accumulation and structural development. Other climate and soil variables were retained in the various models but had weaker effects. Spatial extrapolations of the HBMs indicated that the central and eastern parts of the study region are most suitable for biomass accumulation; however, these may not correspond to the areas that historically supported the highest biomass Brigalow forests. We conclude that carbon and restoration goals are largely congruent within areas of similar climate. At the regional scale, however, spatial prioritization of restoration and carbon projects may only be aligned where carbon benefits will be high. © 2010 by the Ecological Society of America

Common species contribute little to spatial patterns of functional diversity across scales in coastal grasslands

Funder: Rural and Environment Science and Analytical Services Division; Id: http://dx.doi.org/10.13039/100011310Funder: Scottish Government; Id: http://dx.doi.org/10.13039/100012095Abstract: Spatial patterns of functional diversity are important in understanding community assembly as well as spatial variation in ecosystem functioning, yet the contribution of different species to these patterns remains unclear, making it difficult to generalise. Several studies have previously used a sequential addition approach to determine the subsets of species that contribute to the spatial distribution of species richness, frequently showing the importance of common species to richness patterns. This approach, however, has not been applied to functional diversity despite the central role of species traits in community ecology. Here we use a multiscale survey of plants from the Machair grassland system of the Western Isles of Scotland to ask the following questions: (i) Do functional diversity patterns correlate better with geographically common or geographically rare species?; (ii) Do their relative contributions vary with spatial scale?; and (iii) Do these patterns vary between functional diversity measures? We show that while species richness patterns correlate with geographically common species, common species contribute less than expected to spatial patterns of functional diversity at frequently used spatial monitoring scales. The relative contribution of species to overall biodiversity patterns, however, can vary with spatial scale. Synthesis. Surveying only common species may be inadequate for estimating spatial patterns of functional diversity, especially if using occurrence as opposed to percentage cover or abundance data, and spatial scale needs to be considered when designing surveys. Our approach highlights the species that may be adequate indicators of different dimensions of biodiversity and contributes to our understanding of the distribution of functional diversity in space

Evaluasi Program Pembelajaran Bahasa Inggris

The aims of this research were to evaluate English learning in context, input, process, product. This research was an evaluation research. The sources of the research were students of English for Children class at English Smart Bandar Jaya. The data was collected through observation, test, and documentation which was analyzed descriptive quantitative. The conclusions in this research were : 1) the of context value of sub component at the pre-condition is fair, the input value of component sub component infrastructure,human resources and curriculum is poor, the result of process component sub component of planning and english learning implementation is fair, and the product component value in the learning result of the students is fair, and 2) the recommendation of this research,the general manager needs to observe and change the curriculum for a better future, then provide laboratory room for listening, the teachers should make a lesson plan based on the syllabus for each competency.Penelitian ini bertujuan untuk mengevaluasi pembelajaran Bahasa Inggris pada komponen context, input, process, product. Penelitian ini merupakan penelitian evaluasi. Sumber penelitian adalah pembelajar kelas English for Children di English Smart Bandar Jaya. Data dikumpulkan dengan observasi, tes dan dokumentasi kemudian dianalisis secara deskriptif kuantitatif. Kesimpulan dalam penelitian ini : 1) nilai context sub komponen kondisi awal lembaga cukup, nilai input sub komponen fasilitas sarana prasarana, tenaga pendidik dan kurikulum cukup, nilai process sub komponen perencanaan dan pelaksanaan pembelajaran bahasa Inggris kurang, dan nilai komponen product pada hasil belajar pembelajar cukup, dan 2) rekomendasi penelitian ini, kepala lembaga perlu meninjau atau mengubah kurikulum lembaga untuk pembaruan ke arah yang lebih baik, disediakan ruang laboratorium untuk menunjang pembelajaran listening, tentor harus membuat lesson plan yang disusun berdasarkan silabus unit kompetensi

Human land use is comparable to climate as a driver of global plant occurrence and abundance across life forms

Publication history: Accepted - 23 May 2023; Published online - 9 June 2023.Aim Historically, climate has been a dominant driver of global vegetation patterns. Recently, ecological understanding has been updated to acknowledge the influence of human land use (the dominant driver of biodiversity change) in shaping global vegetation patterns. We test whether Raunkiær's life form, a plant classification system designed to reflect climatic drivers, affects how plants respond to both land use and climate. Location Forty-one countries across six continents. Time period 1990 to 2013. Major taxa studied Terrestrial plants. Methods Combining data from the biodiversity and land use database PREDICTS, and plant trait databases TRY and BIEN, we use generalized linear mixed models with weighted effects coding to test whether Raunkiær's life form affects plant response to land use and climate in over 4800 species at over 300 sites globally. Results We provide evidence that human land use is comparable to climate in influencing life form occurrence and that land use produces divergent outcomes across life forms. Main conclusions Combined with climatic suitability, land use acts as a filter contracting the realized niche of trees and expanding the realized niche of disturbance-tolerant species. Our results highlight the fundamental role of human activity in shaping species' distribution.Irish Research Council, Grant/Award Number: GOIPD/2016/324, GOIPG/2018/475 and IRCLA/2017/60; Prince Albert II of Monaco Foundation (though Plants Under Pressure II), Grant/Award Number: E/M014533/