Biology subjects

Cant, J.

Publications and source records attributed to Cant, J..

10 recordsLinked to original sources

bioRxiv2026

Adult corals enhance juvenile recruitment through cumulative ecological niche construction

Ecosystem engineers are ecological niche constructors: by modifying local environments, they alter the conditions under which organisms establish, persist and interact. Although niche construction is often framed as a population-level evolutionary feedback, it could also operate at the assemblage level when communities collectively shape their environments and filter future recruitment. Reef-building corals provide a perfect system to test this idea because adult colonies form three-dimensional carbonate structures that can persist after colony death, creating an inherited habitat for subsequent coral generations. Here, we tested whether coral recruitment to the juvenile stage was associated with local adult coral abundance, reef structure, and larval settlement supply. Combining spatially explicit coral censuses, photogrammetric reef digital elevation models and data from settlement tiles across 15 reef sites at two time points at Jiigurru, Great Barrier Reef, we found that juvenile abundance increased additively on the log scale with adult abundance and with fractal dimension, a metric of fine-scale structural complexity. Surface rugosity had weaker effects, and interactions between adult abundance and habitat structure were limited, indicating largely additive, rather than synergistic or antagonistic, effects. Our results show that both adult assemblages and the concurrent structural complexity, consistent with assemblage-level niche construction and ecological inheritance theory, shape coral recruitment.

ecology↗

bioRxiv2025

Current estimates of population resilience do not predict resilience to directional environmental shifts

Natural systems worldwide are exposed to gradual changes imposed by directional environmental shifts, known as ramp disturbances. However, contemporary assessments of population resilience focus on the resistance and recovery of systems following one-off (i.e., pulse) disturbances. Thus, our current perception of demographic resilience overlooks the potential impacts of the cumulative effects of ramp disturbances on population dynamics. Simulating 50-year ramp disturbance scenarios upon the survival and fecundity dynamics of 511 populations across 344 species, we illustrate non-linear patterns in how directional environmental shifts will reshape the resilience of natural populations. Accordingly, existing estimates of population resilience are not robust against a backdrop of ongoing and continuous environmental change. Instead, we demonstrate the need to quantify how the relative partitioning of energetic resources across survival vs. fecundity informs population resilience. Our findings challenge the use of well-established approaches in forecasting population resilience to ongoing global change.

ecology↗

bioRxiv2024

Habitat complexity defines global biological and societal landscapes

The three-dimensional structure of land- and seascapes links biotic and abiotic processes to shape how organisms use their environments. Much effort has been dedicated to understanding this relationship between structural complexity and biodiversity. However, tailored, system-specific approaches to quantifying structural complexity preclude cross-system comparisons. Expanding a geometric framework developed for quantifying the structural complexity of local-scale surface environments, we generate high-resolution, global maps of the key complexity measures of height range, rugosity, and fractal dimension. We illustrate how patterns in these complexity attributes correspond with the distribution of ecosystems, land cover types, and the presence of people across the globe. Using geometric tools to understand how structural complexity is associated with the arrangement of natural and socio-ecosystems, we can better predict their responses to ongoing global change.

ecology↗

bioRxiv2024

Coupling hydrodynamic drifting simulations and seasonal demographics to forecast the occurrence of jellyfish blooms

O_LIAlthough jellyfish are an important component of coastal marine communities, their public perception is often tainted by their proclivity for aggregating in vast numbers, known as jellyfish blooms. Jellyfish blooms occur worldwide and are associated with major economic ramifications, particularly throughout the fisheries, aquaculture, and tourism sectors. C_LIO_LIForecasting jellyfish blooms is critical in order to manage and mitigate their ecological and economic impacts, but the complex life cycles and cryptic life stages exhibited by most jellyfish species largely precludes accurate predictions of their temporal and spatial occurrence. C_LIO_LIHere we introduce a predictive framework, combining state-of-the-art hydrodynamic simulations and periodic population modelling approaches, to forecast spatial and temporal patterns in the formation of jellyfish blooms. While this framework is sufficiently flexible for accommodating various bloom-forming jellyfish species and impacted coastal regions worldwide, we focus on moon jellyfish (Aurelia aurita) populations within the Baltic Sea as an illustrative example. C_LIO_LIWe emphasise how, through the iterative process of forecasting and model validation, this framework can provide valuable insights for resolving key gaps in our understanding of the drivers of bloom events. Indeed, our framework offers an approach for identifying the, to date, unknown locations of polyp-beds; a crucial parameter in enhancing our capacity to accurately predict the occurrence of jellyfish blooms. Accordingly, our framework, represents a key decision-support tool for mitigating the socioeconomic impacts of bloom formation. C_LI

ecology↗

bioRxiv2022

High-latitude marginal reefs support fewer but bigger corals than their tropical counterparts

AimDespite the awareness that climate change impacts are typically detrimental to tropical coral reefs, the effect of increasing environmental stress and variability on the population size structure of coral species remains poorly understood. This gap in knowledge limits our ability to effectively conserve coral reef ecosystems because size specific dynamics are rarely incorporated. Our aim is to quantify variation in the size structure of coral populations along a tropical-to-subtropical environmental gradient. Location20 coral populations along a latitudinal gradient on the east coast of Australia ([~]23{degrees}S to 30{degrees}S). Time PeriodBetween 2010 and 2018. Major taxa studiedScleractinian corals. MethodsWe apply two methods to quantify the relationship between environmental covariates and coral population size structure along a latitudinal environmental gradient. First, we use linear regression with summary statistics, such as median size as response variables; a method frequently favoured by ecologists. The second method is compositional functional regression, a novel method using entire size-frequency distributions as response variables. We then predict coral population size structure with increasing environmental stress and variability. ResultsCompared to tropical reefs, we find fewer but larger coral colonies in marginal reefs, where environmental conditions are more variable and stressful for corals in the former. Our model predicts that coral populations may become gradually dominated by larger colonies (> 148 cm2) with increasing environmental stress. Main conclusionsWith increasing environmental stress and variability, we can expect shifts in coral population size structure towards more larger colonies. Fewer but bigger corals suggest low survival, slow growth, and poor recruitment. This finding is concerning for the future of coral reefs as it implies populations may have low recovery potential from disturbances. We highlight the importance and usefulness of continuously monitoring changes to population structure over large spatial scales. Data availabilityData is supplied in the supplementary information, or upon request. Once accepted for publication it will be made openly available on Dryad.

ecology↗

bioRxiv2022

Evolutionary processes, not environmental drivers, determine the resilience of natural populations

Escalating climatic and anthropogenic pressures expose ecosystems worldwide to increasingly frequent disturbances. Yet, our ability to forecast the responses of natural populations to these disturbances is impeded by a limited understanding for how exposure to stochastic environments shapes population resilience. Instead, the resilience, and vulnerability, of natural populations to ongoing global change is often presumed based on their contemporary exposure to environmental stochasticity. To test the validity of this assumption, we investigated the association between the resilience attributes (e.g., resistance and recovery) of natural animal and plant populations, and measures of local environmental stochasticity (e.g., spectral frequency and abiotic range); collating data from 2,242 populations across 369 animal, plant, and algal species. Unexpectedly, recent abiotic stochasticity regimes from the past 50 years do not predict the inherent ability of populations to resist or recover from disturbances. Instead, population resilience is strongly affected by phylogenetic relationships among species, with survival and developmental investments shaping their responses to stochastic regimes. Contrary to the classical assumption that exposure to recent environmental shifts confers a greater ability to cope with current and future global change, our findings suggest that population resilience is a consequence of evolutionary processes and/or deep-time environmental regimes. Significance statementPopulations that currently endure more variable abiotic conditions are often expected to be less vulnerable to future increases in climatic variability. However, without defining the link between abiotic variability and the capacity for populations to resist and recover following disturbances (i.e., their resilience), we cannot predict the consequences of ongoing community reassembly. Evaluating the association between measures of abiotic variability and the resilience attributes of 2,242 animal, plant, and algae populations, we discredit the assumption that contemporary exposure to more frequent environmental shifts confers a greater ability to cope with future global change. Instead, the resilience attributes of natural populations appear to have been moulded over longer-term evolutionary timeframes and are thus not a response to more recent experiences.

ecology↗

bioRxiv2021

Coral assemblages at higher latitudes favour short-term potential over long-term performance

The persistent exposure of coral communities to more variable abiotic regimes is assumed to augment their resilience to future climatic variability. Yet, while the determinants of coral population resilience across species remain unknown, we are unable to predict the winners and losers across reef ecosystems exposed to increasingly variable conditions. Using annual surveys of 3171 coral individuals across Australia and Japan (2017-2019), we explore spatial variation across the short- and long-term dynamics of competitive, stress-tolerant, and weedy assemblages to evaluate how thermal variability mediates the structural composition of coral communities. We illustrate how, by promoting short-term potential over long-term performance, coral assemblages can reduce their vulnerability to stochastic environments. However, compared to stress-tolerant, and weedy assemblages, competitive coral taxa display a reduced capacity for elevating their short-term potential. Accordingly, future climatic shifts threaten the structural complexity of coral assemblages in variable environments, emulating the degradation expected across global tropical reefs.

ecology↗

bioRxiv2021

Life history mediates the trade-offs among different components of demographic resilience

Summary paragraphAccelerating rates of biodiversity loss underscore the need to understand how species achieve resilience -their ability to resist and recover from a/biotic disturbances. Yet, the factors determining the resilience of species remain poorly understood, due to disagreements on its definition and the lack of large-scale analyses. Here, we investigate how the life history of 785 natural populations of animals and plants predict their intrinsic ability to be resilient. We show that demographic resilience can be achieved through different combinations of compensation, resistance, and recovery after a disturbance. We demonstrate that these resilience components are highly correlated with life history traits related to the species pace of life and reproductive strategy. Species with longer generation times require longer recovery times post-disturbance, while those with greater reproductive capacity have greater resistance and compensation. Our findings highlight the key role of life history traits to understand species resilience, improving our ability to predict how natural populations cope with disturbance regimes.

ecology↗

bioRxiv2021

Transient amplification enhances the persistence of tropicalising coral populations in marginal high latitude environments.

Predicting the viability of species exposed to increasing climatic stress requires an appreciation for the mechanisms underpinning the success or failure of marginal populations. Rather than traditional metrics of long-term population performance, here we illustrate that short-term (i.e. transient) demographic characteristics, including measures of resistance, recovery, and compensation, are fundamental in the poleward range expansion of hard corals, facilitating the establishment of coral populations at higher-latitudes. Through the annual census of tropical and subtropical Acropora spp. colonies in Japan, between 2017-2019, we show how the transient amplification potential of a subtropical coral population supports its enhanced growth within unstable environmental conditions. The transient dynamics of both the tropical and subtropical populations were strongly influenced by their corresponding recruitment patterns. However, we demonstrate that variation in colony survival and fragmentation patterns between the two populations determines their relative capacities for transient amplification. This latitudinal variation in the transient dynamics of Acropora spp. populations emphasizes that coral populations can possess the demographic plasticity necessary for exploiting more variable, marginal conditions.

ecology↗

bioRxiv2021

Transient demographic approaches can drastically expand the toolbox of coral reef science

Coral communities are threatened by an increasing plethora of abiotic and biotic disturbances. Preventing the ensuing loss of coral coverage and diversity calls for a mechanistic understanding of resilience across coral species and populations that is currently lacking in coral reef science. Assessments into the dynamics of coral populations typically focus on their long-term (i.e. asymptotic) characteristics, tacitly assuming stable environments in which populations can attain their long-term characteristics. Instead, we argue that greater focus is needed on investigating the transient (i.e. short-term) dynamics of coral populations to describe and predict their characteristics and trajectories within unstable environments. Applying transient demographic approaches to the evaluation and forecasting of the responses of coral populations to disturbance holds promise for expediting our capacity to predict and manage the resilience of coral populations, species, and communities.

ecology↗