The introduction and success of non‐native species are both a consequence and a cause of rapid global change. Humans have created novel ecosystems through environmental modification and mass ...movements of organisms around the planet. It has been argued that species biogeographic origin cannot explain or predict ecological impacts and the origin of a species should not influence ecosystem management. This rejection of ‘origin’ is overly simplistic. Origin effects can arise through biased sampling of the types of species transported, the environmental and evolutionary context of their source environments and the communities and environments to which they are introduced. Differences in co‐evolutionary histories between source and recipient environments, and adaptation of introduced species to modified environmental conditions, can also shape origin effects. The high rates and long distances of human‐mediated dispersal have increased the sizes of regional species pools. In addition, human transported, non‐native species can change the function of recipient ecosystems through changes to community composition. We outline how origin effects can cascade through to ecological impact at population, community and ecosystem levels. Synthesis. Non‐native species can have predictable and preventable effects on recipient communities. We identify multiple sources of origin effects and describe the ecological and evolutionary pathways through which origin effects lead to impacts. This functional understanding of origin effects must include human actions. However, species origin should not, on its own, be used as a shortcut for management decisions; origin effects should instead feed into a process whereby ecologists work together with managers, policymakers and broader society to guide decisions on how to respond to the effects of non‐native species.
The identification of patterns in life-history strategies across the tree of life is essential to our prediction of population persistence, extinction, and diversification. Plants exhibit a wide ...range of patterns of longevity, growth, and reproduction, but the general determinants of this enormous variation in life history are poorly understood. We use demographic data from 418 plant species in the wild, from annual herbs to supercentennial trees, to examine how growth form, habitat, and phylogenetic relationships structure plant life histories and to develop a framework to predict population performance. We show that 55% of the variation in plant life-history strategies is adequately characterized using two independent axes: the fast–slow continuum, including fast-growing, short-lived plant species at one end and slow-growing, long-lived species at the other, and a reproductive strategy axis, with highly reproductive, iteroparous species at one extreme and poorly reproductive, semelparous plants with frequent shrinkage at the other. Our findings remain consistent across major habitats and are minimally affected by plant growth form and phylogenetic ancestry, suggesting that the relative independence of the fast–slow and reproduction strategy axes is general in the plant kingdom. Our findings have similarities with how life-history strategies are structured in mammals, birds, and reptiles. The position of plant species populations in the 2D space produced by both axes predicts their rate of recovery from disturbances and population growth rate. This life-history framework may complement trait-based frameworks on leaf and wood economics; together these frameworks may allow prediction of responses of plants to anthropogenic disturbances and changing environments.
Summary
Population ecologists develop theoretical and pragmatic knowledge of how and why populations change or remain stable, how life histories evolve and devise management strategies for ...populations of concern. However, forecasting the effects of global change or recommending management strategies is often urgent, requiring ecologists to work without detailed local evidence while using data and models from outside the focal location or species. Here we explore how the comparative ecology of populations, population macroecology, can be used to develop generalisations within and between species across different scales, using available demographic, environmental, life history, occurrence and trait data. We outline the strengths and weaknesses of using broad climatic variables and suitability inferred from probability of occupancy models to represent environmental variation in comparative analyses. We evaluate the contributions of traits, environment and their interaction as drivers of life history strategy. We propose that insights from life history theory, together with the adaptive capacity of populations and individuals, can inform on ‘persist in place’ vs ‘shift in space’ responses to changing conditions. As demographic data accumulate at landscape and regional scales for single species, and throughout plant phylogenies, we will have new opportunities for testing macroecological generalities within and across species.
When function, not origin, matters Buckley, Yvonne M; Torsney, Andrew
Science (American Association for the Advancement of Science),
02/2024, Volume:
383, Issue:
6682
Journal Article
Peer reviewed
Native and introduced megaherbivores similarly affect plant diversity and abundance.
Species distribution models (SDMs) are increasingly proposed to support conservation decision making. However, evidence of SDMs supporting solutions for on‐ground conservation problems is still ...scarce in the scientific literature. Here, we show that successful examples exist but are still largely hidden in the grey literature, and thus less accessible for analysis and learning. Furthermore, the decision framework within which SDMs are used is rarely made explicit. Using case studies from biological invasions, identification of critical habitats, reserve selection and translocation of endangered species, we propose that SDMs may be tailored to suit a range of decision‐making contexts when used within a structured and transparent decision‐making process. To construct appropriate SDMs to more effectively guide conservation actions, modellers need to better understand the decision process, and decision makers need to provide feedback to modellers regarding the actual use of SDMs to support conservation decisions. This could be facilitated by individuals or institutions playing the role of ‘translators’ between modellers and decision makers. We encourage species distribution modellers to get involved in real decision‐making processes that will benefit from their technical input; this strategy has the potential to better bridge theory and practice, and contribute to improve both scientific knowledge and conservation outcomes.
Zoos contribute substantial resources to in situ conservation projects in natural habitats using revenue from visitor attendance, as well as other sources. We use a global dataset of over 450 zoos to ...develop a model of how zoo composition and socio-economic factors directly and indirectly influence visitor attendance and in situ project activity. We find that zoos with many animals, large animals, high species richness (particularly of mammals), and which are dissimilar to other zoos achieve higher numbers of visitors and contribute to more in situ conservation projects. However, the model strongly supports a trade-off between number of animals and body mass indicating that alternative composition strategies, such as having many small animals, may also be effective. The evidence-base presented here can be used to help guide collection planning processes and increase the in situ contributions from zoos, helping to reduce global biodiversity loss.
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•Water chemistry plays a major role in shaping epilithic diatom assemblages in Irish lakes.•The Lake Trophic Diatom Index (LTDI) is validated for lake classification in Ireland.•Lake ...types and seasonal variability are not major factors for Irish lake diatom classifications.
Periphyton is increasingly used to assess the biological condition of lakes. The predominance of relatively shallow exposed waterbodies in Ireland implies that epilithic diatoms should have a prominent role as bioindicators for the WFD; but epilithic diatom ecology in these Irish systems is poorly described. We characterised spring and summer diatom populations in diverse periphyton communities in 91 Irish lake waterbodies. Six assemblage clusters of diatom species were identified, and variation in their assemblages was predominately associated with environmental gradients of acidity-alkalinity, total phosphorus, and true colour. Diatom composition differed amongst high status lakes in three a priori defined lake alkalinity groups commonly used as a diatom typology for lake classification. However, when waterbodies were evaluated with a lake trophic diatom index (LTDI) their distribution of ‘expected-values’ was equivalent. The LTDI was highly correlated with total phosphorus but also had similar responses in the three lake alkalinity types. These findings indicated that lake typology had a limited role for diatom classification with the LTDI in Ireland. Matched spring and summer sampling across wide environmental gradients allowed the role of seasonality to be investigated. Relatively few benthic diatoms had a significant seasonal indicator value suggesting that unbiased monitoring of the epilithon is possible during any month of the growing season in comparable temperate waterbodies. However, temporal variability was lower at low values of the LTDI and increased unpredictably on a lake by lake basis thereafter. Given that lake diatom classification has been validated we suggest that the approach could be developed and used for more targeted assessment objectives.
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 bryozoanBugula 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.
Abstract
Motivation and aim
Mapping the spatial distribution of biodiversity is critical for understanding its fundamental drivers (e.g. speciation, environmental filtering) as well as for ...conservation assessment. An important dimension of this topic is how the distributions of subsets of species contribute to the overall distribution of biodiversity. Although studies have previously investigated the role of geographically common and rare species in determining these patterns, their respective contributions appear to vary between studies. Knowing which species contribute disproportionately to the spatial distribution of biodiversity enables the identification of key indicator species for biodiversity assessments across large areas and is important for prioritising areas for conservation actions. An extensive review of the literature was carried out to synthesise research on how geographic rarity contributes to spatial patterns of biodiversity. We identify potential explanations for the discrepancies in findings between studies and identify opportunities for further research.
Results
Many studies on the contribution of geographic commonness and rarity to the spatial distribution of biodiversity focus on species richness. A prevalent view is that common (widespread) species contribute disproportionately, although this is not ubiquitous across studies due to factors such as the geographic extent from which relative rarity is quantified. We identify research pathways that will further improve our knowledge of how geographically common and rare species shape the spatial distribution of biodiversity including the impact of spatial scale on species contributions and the incorporation of biodiversity components beyond taxonomic alpha diversity, that is functional and phylogenetic diversity.
Main conclusions
Future research should incorporate multiple biodiversity components and model scale dependency. This will further our knowledge on the underlying processes that shape the spatial variation of biodiversity across the planet and help inform biological surveys and conservation activities.
Animals exhibit an extraordinary diversity of life history strategies. These realized combinations of survival, development and reproduction are predicted to be constrained by physiological ...limitations and by trade-offs in resource allocation. However, our understanding of these patterns is restricted to a few taxonomic groups. Using demographic data from 121 species, ranging from humans to sponges, we test whether such trade-offs universally shape animal life history strategies. We show that, after accounting for body mass and phylogenetic relatedness, 71% of the variation in animal life history strategies can be explained by life history traits associated with the fast-slow continuum (pace of life) and with a second axis defined by the distribution of age-specific mortality hazards and the spread of reproduction. While we found that life history strategies are associated with metabolic rate and ecological modes of life, surprisingly similar life history strategies can be found across the phylogenetic and physiological diversity of animals.
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