Biology subjects

Chapman, H. M.

Publications and source records attributed to Chapman, H. M..

3 recordsLinked to original sources

bioRxiv2024

Adaptive Differentiation in the General-Purpose Genotype Invasive Plant Erythranthe guttata

O_LIHighly plastic general-purpose genotypes are a frequent occurrence among invasive plants. Yet, it remains uncertain to what extent genetic adaptation can co-occur with such elevated levels of plasticity. Understanding the interplay between these two evolutionary strategies is essential to better predict invasive success and future climate change responses. C_LIO_LIWe investigated the potential for local adaptation along an altitudinal gradient in introduced New Zealand populations of the highly plastic invasive herb, Erythranthe guttata. We asked a) whether there were phenotypic differences between upland and lowland E. guttata populations along our gradient; b) whether any differences were consistent with known adaptive patterns; and c) whether any adaptive patterns exist alongside high plasticity to elevation. C_LIO_LISamples from 38 E. guttata populations from upland and lowland Canterbury were grown from cuttings in a lowland and an upland common garden, where we measured a broad range of growth and reproductive traits. C_LIO_LIWe found significant adaptive differentiation between upland and lowland populations over almost all measured traits. Upland populations had earlier and more intense flowering compared with lowland populations. Lowland plants were taller and had larger leaves with higher photosynthetic rates than upland plants. These differences occurred alongside high levels of unspecialised plasticity to the growing environment. C_LIO_LISynthesis: We found that over a period of less than 150 years the environment along an altitude gradient of 120km has selected for distinct lowland and upland phenotypes of E. guttata. These changes reflect common selective pressure associated with altitude gradients, increasing reproductive success at higher altitudes and increased competitive ability at lower altitudes. This rapid local adaptation occurred alongside high plasticity within the growing environment, showing that highly plastic invasive species still retain the capacity to genetically adapt to novel environments. C_LI

evolutionary biology↗

bioRxiv2024

Discordant changes in foliar and reproductive phenology of tropical dry-forest trees under increasing temperature and decreasing wet-season rainfall

O_LIPlant phenology drives population dynamics and forest productivity; it is also impacted by shifting environmental cues under climate change such as more prevalent drought. It is imperative to better understand how species and community phenology respond to climate change in leaf turnover and reproduction, both of which are required to integrate phenology into full life-cycle assessments. C_LIO_LIHowever, relatively few studies to-date examined the quantity and timing of phenology simultaneously. We demonstrate that the simultaneous assessment of phenological quantity and timing across multiple organs reveals more nuanced and holistic insights into the consequences of climate change. C_LIO_LIExtending a regression approach based on Fourier series, we decomposed the long-term (2004-2020) monthly leaf shedding, leaf flush, flowering and fruiting of 617 trees across 94 taxa at a Nigerian seasonally dry tropical forest into three periodic components--mean intensity, amplitude and phase--which respectively represents the total quantity, pulse concentration and peak timing of phenology. We then related each periodic component to warming minimum temperature and drying wet-season rainfall. C_LIO_LIWe found that climate explained more variation in phenological amplitudes (14-66%) compared to mean intensity and timing (6-49%). In drier years, more species (18%) shed leaves earlier (changing timing) or in more concentrated pulses (changing amplitude), while only a few (2%) shed leaves in greater total amounts (changing mean intensity). This combined with the decreased mean intensity of leaf flush imply a lower primary productivity as trees deployed fewer leaves for a shorter period. Some species (30%) produced fewer fruits despite no change or even increase in flowering; in a few species this could be explained by a shortened flowering period that limited pollination. At the community level, reproduction became more synchronous, potentially creating periods of scarcity for consumers. C_LIO_LISynthesis: Our findings highlight several contrasting yet complementary phenology- climate insights, indicating that assessments of forests climate resilience necessitate multiple aspects of phenology rather than a single performance indicator. The decline of leaf and fruit productions, as well as the temporal mismatches in leaf turnover and reproduction, will have cascading impacts on trophic interactions and nutrient cycling. C_LI

ecology↗

bioRxiv2022

Relative roles of genetic variation and phenotypic plasticity in the invasion of monkeyflower Erythranthre gutatta in New Zealand

Evolutionary processes which increase the probability of an introduced plant species becoming invasive include high levels of genetic diversity and phenotypic plasticity. Naturalised in New Zealand, monkeyflower, (Erythranthre gutatta), a clonally spreading herb of waterways and seepage areas native to the Western USA, shows marked variation in a range of vegetative, reproductive and inflorescence traits. We used two common gardens differing in elevation to explore the relative contribution of genetic versus plastic variation within nine traits among 34 monkeyflower clones from across the New Zealand South Island. We looked for evidence of clinal variation across elevation gradients and for home site advantage. We found both high genetic diversity and trait plasticity explain the observed variation, although less evidence for adaptive plasticity. Most genetic variation was observed in the lowland garden (9m a.s.l.), where the overall trend was for above ground dry weight to be lower, and horizontal shoot length greater, than at the montane garden (560m a.s.l). We found no evidence of local adaptation to any of the measured environmental variables. However, we observed a pattern of higher biomass and higher plasticity at lower versus higher elevations and in clones originating from lower elevation sites.

ecology↗