Biology subjects

Pearse, W. D.

Publications and source records attributed to Pearse, W. D..

At least 19 recordsLinked to original sources

bioRxiv2026

A global assessment of how biodiversity enhances agroecosystem function

1. Agriculture is the most significant driver of global land-use change, placing increasing pressure on biodiversity. Balancing rising food demand with the need to conserve biodiversity is therefore an urgent challenge, especially as biodiversity can underpin key ecosystem functions that support agricultural systems. A greater general understanding of how biodiversity influences agroecosystem function is critical for developing agricultural practices that benefit both agricultural production and wider ecosystem processes. 2. Using a global dataset of 184 biodiversity-agroecosystem function relationships covering agricultural and silvicultural systems, we developed a classification system for different biodiversity-enhancing approaches, ranging from the planting of multiple crop species to creating tree islands or flower strips, providing the first comprehensive assessment of how these approaches affect agroecosystem function. 3. We found biodiversity enhancement generally had a positive, or at least neutral, association with multiple agroecosystem functions, indicating that it contributes to agricultural sustainability. Crop diversification had the greatest impact on key agroecosystem functions compared to other practices, likely due to the low heterogeneity already present in agricultural systems and the scale at which crop diversification is applied and measured. Overall, biodiversity's largest effect was on multifunctionality, highlighting its role in supporting the simultaneous delivery of multiple agroecosystem functions. 4. Variability in relationships among systems and agroecosystem function categories suggests that no single biodiversity-enhancing approach will universally benefit all functions simultaneously. Instead, a combination of approaches, assessed through their contribution to overall multifunctionality, is likely to be most effective, ensuring that agricultural sustainability claims reflect benefits across systems. 5. Policies should incentivise biodiversity-enhancing management approaches as effective strategies to improve agroecosystem multifunctionality, benefiting both agricultural productivity and the wider ecosystem.

ecology↗

bioRxiv2026

Revealing centurial changes in butterfly wing shape via the automated analysis of museum specimens.

O_LIUnderstanding how environmental change is shaping organismal morphology of key functional guilds is important, since morphological traits determine the delivery of ecosystem services we depend upon. Adult butterflies, as pollinators, are commercially and culturally important, but the longitudinal data across appropriate time frames to understand trait response trends are generally limited. C_LIO_LIHere we leverage digitised museum butterfly specimens to help fill this data gap by employing automated methods (machine learning and Elliptical Fourier Analysis) to achieve high-throughput measurements of traits across large collections. We analyse how wing shape (the outline of the whole butterfly) varies in over 178,000 specimens of 65 butterfly species collected across the UK and Ireland over two centuries. C_LIO_LIWe identify two major biologically attributable axes of butterfly wing shape: aspect ratio and asymmetry. Analysing a subset of these specimens (108,511 from 34 species), we find directional trends in wing shape. Over a period of 105 years (1901-2006), wings generally became narrower and longer in over half (18) of the studied species. This response may be affecting butterfly behaviour by favouring gliding flight. C_LIO_LIUltimately, we highlight that historical processes including temperature change have historically shaped butterfly wing shape. We demonstrate that studying whole wing outline using automated methods allows us to extract the high-throughput, long-term data required to understand the responses of ecologically important taxa at scales that we were previously unable to achieve. C_LI

ecology↗

bioRxiv2026

Systematic mapping shows monitoring, evaluation, and engagement are needed to build an evidence base for rewilding

Rewilding is a landscape recovery approach that seeks to enhance functioning of degraded ecosystems by reinstating natural processes and is increasingly being adopted by organisations and landowners. Despite its popularity, there is no accepted way to assess rewildings impacts. This is due in part to inconsistent monitoring and evaluation. Here we report the results from a systematic map of the academic and grey literature on monitoring and evaluation in rewilding case studies. We find that researchers and practitioners are focused on different aspects of rewilding, and that limited recording of case study details and lack of robust experimental design make it difficult to pool and compare data. We identify challenges facing researchers and rewilding practitioners seeking to build a robust evidence base from which to evaluate rewilding outcomes. These challenges include resources as well as spatial and time constraints, which all limit the consistency of data gathering among projects. More comparisons across rewilding projects, better standardisation of data collection and data recording methods, and increased collaboration between researchers and practitioners could go some way to remedy this. We provide recommendations for planning and implementing studies of rewilded landscapes to aid monitoring and evaluation. These include the broad adoption of low-cost and scalable survey designs with greater focus on comparisons across sites, and continued effort towards open-source data storage.

ecology↗

bioRxiv2025

Integrating functional and phylogenetic perspectives reveals new priorities for bird and mammal conservation

Finite resources dictate that conservation biologists must prioritise some species over others. Conservation metrics, such as EDGE (Evolutionarily Distinct and Globally Endangered; EDGE1) and FUSE (Functionally Unique, Specialised and Endangered), make prioritisation based on species evolutionary or functional distinctiveness, respectively, and degree of threat. EDGE is in part based on the rationale that the evolutionary distinctiveness it captures serves to maximise biodiversity in form and function. However, doubts exist as to whether or not evolutionary distinctiveness truly serves as a proxy for functional distinctiveness, and, therefore, if the prominent use of EDGE lists by conservation practitioners adequately protects functional distinctiveness. To address this, we conducted a direct global comparison of EDGE against FUSE. Unlike EDGE, FUSE directly measures and prioritises functional distinctiveness. Here, we compare EDGE and FUSE scores for two well-studied groups: mammals (n = 5319 species) and birds (n = 7932 species). These groups are central to global conservation and, until now, have not been assessed under FUSE. We find that species rankings under EDGE and FUSE differ significantly, highlighting that these two metrics capture distinct, complementary aspects of biodiversity. This suggests that conservation strategies based solely on EDGE may overlook species with critical functional roles. Rather than assuming alignment between evolutionary and functional distinctiveness, we propose integrating both within a single measure, leveraging the strengths and benefits of each. To this end, we present a new conservation metric - EFUSE (Evolutionarily and Functionally Unique, Specialised, and Endangered) - which incorporates both evolutionary and functional distinctiveness into a single measure. EFUSE ensures that important components of biodiversity, which relate to ecosystem functioning, natures future contributions to people, and the intrinsic value of species, are adequately maximised in conservation decision-making.

ecology↗

bioRxiv2025

Systematic review of biodiversity monitoring shows gradual rise of scaleable and automated methods and inherent spatial and taxonomic biases

1Global policy efforts to reverse biodiversity declines are hindered by a lack of clarity over how to measure biodiversity. The debate over the best ways to define biodiversity and which metrics to use has taken place in the absence of a clear, holistic view of how biodiversity has been, and is currently, measured. This gap has hindered us moving from discussion to action on conserving biodiversity. Here we track trends in biodiversity measurement, using a dataset of >2400 papers across the last 22 years, identifying trends, biases, and gaps in the assessment of nine major taxonomic groups (Invertebrate, fish, aquatic mammal, terrestrial mammal, bird, herpetofauna, fungi, microbe and plant). We found proportional declines in invertebrate, but increases in fish, surveys over time, and fewer assessments of biodiversity in Africa and Oceania. Although we do find an increase in the use of high-throughput, scaleable methods such as eDNA and camera-traps, their uptake is more modest than might be expected and shows signs of having already plateaued. We argue that emerging technologies can, but remain underutilised in addressing the systematic biases in our understanding of biodiversity, and so in helping guide and track our progress towards restoring and saving biodiversity.

ecology↗

bioRxiv2025

Drivers of individual plant species contributions to β-diversity are scale-dependent

Species introductions and native extirpations are driving biotic homogenisation in plant communities by reducing {beta}-diversity. Individual species vary in their contributions to {beta}-diversity (Species Contribution to {beta}-Diversity; species-{beta}), yet our understanding of how species characteristics shape these contributions remains limited. Additionally, although the ecological processes influencing {beta}-diversity are known to vary with spatial scale, we lack understanding of how species contributions, or their underlying determinants, change across scales. Here, we modelled how plant functional traits, phylogenetic relatedness, and introduction status influence their contributions to {beta}-diversity using plant community data from 429 plots surveyed from 2017-2023 across three nested spatial scales (up to 1 km2) in nine sites spanning four countries. We extended the analysis to broader spatial extents (100 km2 to the entire UK) using GBIF occurrence data. We found that functional traits associated with competitive ability influenced species-{beta}, but the direction and strength of their effects varied with scale. Likewise, phylogenetic novelty increased species-{beta} at small scales but reduced it at larger ones. After accounting for traits and phylogeny, introduced species consistently contributed less to {beta}-diversity than native species--especially at broader spatial extents. These results demonstrate that species ecological and evolutionary characteristics shape their contributions to {beta}-diversity, but that these effects are scale-dependent. Our findings highlight the importance of scale-explicit approaches in understanding both the determinants of {beta}-diversity, and how we can combat its loss to mitigate biotic homogenisation.

ecology↗

bioRxiv2025

Using landscape biodiversity metrics to assess rewilding: a space-for-time comparison between the Knepp Estate and an agricultural baseline at Boothby Wildland

O_LIThe biodiversity crisis is often framed in terms of the reduction of species found at a site: a (alpha) diversity. However, changes in species composition across a landscape - b (beta) diversity - caused by biotic homogenisation are part of the same crisis. Much biotic homogenisation in British terrestrial landscapes in the post-war period (1945 onwards) has been driven by agricultural conversion and intensification. Restoration efforts must therefore contend with restoring agricultural land to some desired state, and rewilding has emerged as a potential solution to this problem. C_LIO_LIHere we quantify rewilding success by comparing a- and b-diversity of plant assemblages across two study systems in different stages of rewilding. Boothby Wildland is an arable farm recently given over to rewilding, while the Knepp Estate is an ex-arable and dairy farm currently >20 years into rewilding. We assessed a-diversity within, and b- diversity across, these two landscapes using 3 years of plant survey data (2022-2024). C_LIO_LIWe confirmed expected differences between a baseline and rewilded landscape and explored the changes in a brand new rewilded landscape in its early years of progress. As expected, the plant community at the Knepp Estate is relatively stable while that of Boothby Wildland is changing rapidly, and we discuss the landscape impacts of different herbivory regimes on recovery. C_LIO_LISynthesis and applications. We also show that spatial metrics for SESMPD and SESMNTD can distinguish between a rewilded and degraded landscape. This suggests that changes in the structure of biodiversity across landscapes can be quantified using analyses that account for spatial structure in metrics. We call for further research to see if a spatial approach of this kind can be used as a general metric of success in rewilding. C_LI

ecology↗

bioRxiv2024

YOLO-Behaviour: A simple, flexible framework to automatically quantify animal behaviours from videos

Manually coding behaviours from videos is essential to study animal behaviour but it is labour-intensive and susceptible to inter-rater bias and reliability issues. Recent developments of computer vision tools enable the automatic quantification of behaviours, supplementing or even replacing manual annotations. However, widespread adoption of these methods is still limited, due to the lack of annotated training datasets and domain-specific knowledge required to optimize these models for animal research. Here, we present YOLO-Behaviour, a flexible framework for identifying visually distinct behaviours from video recordings. The framework is robust, easy to implement, and requires minimal manual annotations as training data. We demonstrate the flexibility of the framework with case studies for event-wise detection in house sparrow nestling provisioning, Siberian jay feeding, human eating behaviours, and frame-wise detections of various behaviours in pigeons, zebras, and giraffes. Our results show that the framework reliably detects behaviours accurately, and retrieve comparable accuracy metrics to manual annotation. However, metrics extracted for event-wise detection were less correlated with manual annotation, and potential reasons for the discrepancy between manual annotation and automatic detection are discussed. To mitigate this problem, the framework can be used as a hybrid approach of first detecting events using the pipeline and then manually confirming the detections, saving annotation time. We provide detailed documentation and guidelines on how to implement the YOLO-Behaviour framework, for researchers to readily train and deploy new models on their own study systems. We anticipate the framework can be another step towards lowering the barrier of entry for applying computer vision methods in animal behaviour.

animal behavior and cognition↗

bioRxiv2024

Pervasive patterns in the songs of passerine birds resemble human music universals and are linked with production and cognitive mechanisms

Music is a complex learned behavior that is ubiquitous among humans, and many musical patterns are shared across geography and cultures ("music universals"). Knowing whether these universals are specific to humans or shared with other animals is important to understand how production-related factors (motor biases and constraints) or cognitive factors (learning) contribute to the emergence of these acoustic patterns. Bird song is often described as an animal analogue of human music, and some studies of individual avian species highlight acoustic similarities between bird song and music. However, expansive and comparative approaches are necessary to identify universal patterns within bird song, reveal mechanisms associated with these patterns, and draw parallels to music universals. Here, we adopt such an approach and analyze the prevalence of acoustic patterns (sequences) across [~]300 species of passerines, spanning both oscines (songbirds; vocal learners) and their sister clade, suboscines (passerines that produce songs that are not learned), as well as within a global corpus of human vocal music. This approach allowed us to directly test hypotheses that phonation mechanisms or vocal learning shape the emergence of universal patterns. We first document acoustic patterns that were widely shared across passerines and similar to music universals (e.g., small pitch intervals), highlighting the role of shared vocal production mechanisms in these patterns. Consistent with a contribution of vocal learning, we observed patterns (e.g., alternation in durations) there were more similar between oscines and humans than between suboscines and humans. Interestingly, we also discovered patterns (e.g., pitch alternation) that were inconsistent with a contribution of vocal learning and were more similar between suboscines and humans than between oscines and humans. This research provides the broadest evidence of shared universals in vocal performance across birds and humans and highlights convergent mechanisms shaping communication patterns.

animal behavior and cognition↗

bioRxiv2024

Variable responses of individual species to tropical forest degradation

The functional stability of ecosystems depends greatly on interspecific differences in responses to environmental perturbation. However, responses to perturbation are not necessarily invariant among populations of the same species, so intraspecific variation in responses might also contribute. Such inter-population response diversity has recently been shown to occur spatially across species ranges, but we lack estimates of the extent to which individual populations across an entire community might have perturbation responses that vary through time. We assess this using 524 taxa that have been repeatedly surveyed for the effects of tropical forest logging at a focal landscape in Sabah, Malaysia. Just 39 % of taxa - all with non-significant responses to forest degradation - had invariant responses. All other taxa (61 %) showed significantly different responses to the same forest degradation gradient across surveys, with 6 % of taxa responding to forest degradation in opposite directions across multiple surveys. Individual surveys had low power (< 80 %) to determine the correct direction of response to forest degradation for one-fifth of all taxa. Recurrent rounds of logging disturbance increased the prevalence of intra-population response diversity, while uncontrollable environmental variation and/or turnover of intraspecific phenotypes generated variable responses in at least 44 % of taxa. Our results show that the responses of individual species to local environmental perturbations are remarkably flexible, likely providing an unrealised boost to the stability of disturbed habitats such as logged tropical forests.

ecology↗

bioRxiv2023

BUMBLE BEE RESPONSES TO CLIMATE AND LANDSCAPES: INVESTIGATING HABITAT ASSOCIATIONS AND SPECIES ASSEMBLAGES ACROSS GEOGRAPHIC REGIONS IN THE UNITED STATES OF AMERICA

Bumble bees are integral pollinators of native and cultivated plant communities, but species are undergoing significant changes in range and abundance on a global scale. Climate change and land cover alteration are key drivers in pollinator declines; however, limited research has evaluated the cumulative effects of these factors on bumble bee assemblages. This study tests bumble bee responses to climate and land use by modeling 1) occupancy (presence/absence); 2) species richness; 3) species-specific habitat requirements; and 4) assemblage-level responses across geographic regions. We integrated richness, abundance, and distribution data for 18 bumble bee species with site specific bioclimatic, landscape composition, and landscape configuration data to evaluate the effects of multiple environmental stressors on bumble bee assemblages throughout 433 agricultural fields in Florida, Indiana, Kansas, Kentucky, Maryland, South Carolina, Utah, Virginia, and West Virginia from 2018 to 2020. Increased prevalence of attractive crops was associated with increased bumble bee presence, while higher maximum temperature of warmest month and unattractive crops were linked to bumble bee absences. Bumble bee species richness was positively correlated with attractive crops and elevation but declined with precipitation of the wettest month. Moreover, species richness increased as maximum temperature of warmest month approached 29{degrees}C but declined at they rose to 36{degrees}C, suggesting a potential temperature threshold around 33{degrees}C. Distinct east vs. west groupings emerged when evaluating species-specific habitat associations, prompting a detailed evaluation of bumble bee assemblages by geographic region. Overall, climate and land use combine to drive bumble bee occupancy and assemblages, but how those processes operate is idiosyncratic and spatially contingent across regions. From these findings, we suggested regionally specific management practices to best support rich bumble bee assemblages in agroecosystems. Results from this study contribute to a better understanding of climate and landscape factors affecting bumble bees and their habitats throughout the USA.

ecology↗

bioRxiv2023

How to define, use, and interpret Pagel's lambda (lambda) in ecology and evolution

1Pagels {lambda} (lambda) is a critical tool in ecology and evolution for describing trait evolution, imputing missing species data, and generalising ecological relationships beyond their study system. Yet the interpretation of {lambda} depends on context, and there are many misconceptions about metrics that are similar but not identical to {lambda}. As an index of phylogenetic signal applied to continuous traits, {lambda} typically (but not always) ranges between 0 and 1, and is a rate-independent measure of the degree to which closely-related species resemble one-another relative to a Brownian motion expectation. But this measure is biased by non-random species sampling--a common characteristic of ecological data--which also makes phylogenetic imputation of missing traits challenging. The {lambda} estimated in regression models has little to do with the phylogenetic signal of measured traits and is better considered as either a statistical correction or a measure of the impact of unmeasured (latent) traits in the model. In other contexts, such as hierarchical models including intra-specific variation, {lambda} is frequently confused with distinct metrics such as h2. We show how confusion in defining and using {lambda} can mislead our interpretation of ecological and evolutionary processes. Open research statementNo data were used or collected as part of this work.

evolutionary biology↗

bioRxiv2022

Variation in near-surface soil temperature drives plant assemblage insurance potential

O_LIStudying how assemblages vary across environmental gradients provides a baseline for how assemblages may respond to climate change. Per the biological insurance hypothesis, assemblages with more variation in functional diversity will maintain ecosystem functions when species are lost. In complement, environmental heterogeneity supports landscape-scale ecosystem functionality (i.e. spatial insurance), when that variation includes environments with more abundant resources. C_LIO_LIWe use the relationship between vascular plant functional diversity and microenvironment to identify where assemblages are most likely to maintain functionality in a mountainous fieldsite in northeastern Utah, USA. We assessed how life history strategies and information about phylogenetic differences affect these diversity-environment relationships. C_LIO_LIWe found less functionally dispersed assemblages, that were shorter and more resource-conservative on hotter, more variable, south-facing slopes. In contrast, we found more functionally dispersed assemblages, that were taller and more resource-acquisitive on cooler, less variable, north-facing slopes. Herbaceous and woody perennials drove these trends. Additionally, including information about phylogenetic differences in a dispersion metric indicated that phylogeny accounts for traits we did not measure. C_LIO_LISynthesis. At our fieldsite, soil temperature acts as an environmental filter across aspect. If soil temperature increases and becomes more variable, the function of north- vs. south-facing assemblages may be at risk for contrasting reasons. On south-facing slopes, assemblages may not have the variance in functional diversity needed to respond to more intense, stressful conditions. Conversely, assemblages on north-facing slopes may not have the resource-conservative strategies needed to persist if temperatures become hotter and more variable. We suggest that studying dispersal traits, especially of perennial species, will provide additional insight into whether this landscape will maintain function as climate changes. C_LI

ecology↗

bioRxiv2022

Consistent, linear phenological shifts across a century of observations in South Korea

The Korea Meteorological Agency (KMA) has monitored flowering dates over the past 100 years for seven economically important woody plant species. This unique dataset is perfect for understanding whether historical patterns of phenological plasticity are breaking down in the face of recent and rapid climate change. Here we show that a scientist armed only 50 years into this study would have been able to predict the phenological shifts of the last 50 years with a high degree of accuracy. This is despite record-breaking warm temperatures and unprecedented early flowering, suggesting consistency in phenological shifts over time.

ecology↗

bioRxiv2022

EDGE2: advancing the prioritisation of threatened evolutionary history for conservation action

The global biodiversity crisis threatens the natural world and its capacity to provide benefits to humans into the future. The conservation of evolutionary history, captured by the measure phylogenetic diversity (PD), is linked to the maintenance of these benefits and future options. The Evolutionarily Distinct and Globally Endangered (EDGE) metric has, since 2007, been used to identify species for conservation action that embody large amounts of threatened evolutionary history. In 2017, we convened a workshop to update the EDGE metric to incorporate advances in the field of phylogenetically-informed conservation. Building on that workshop, we devised the metric EDGE2, which we present here. EDGE2 uses a modular, tiered approach to provide priority rankings--and associated measures of uncertainty in both phylogenetic and extinction risk data--for all species in a clade. EDGE2 takes into account the extinction risk of closely-related species to better reflect the contribution a species is expected to make to overall PD in the future. We applied EDGE2 to the worlds mammals to identify an updated list of priority EDGE species and compare the results with the original EDGE approach. Despite similarity in the priority lists produced between EDGE and EDGE2, EDGE2 places greater priority on species with fewer close relatives on the Tree of Life. As we approach a crossroads for global biodiversity policy, EDGE2 exemplifies how academic and applied conservation biologists can collaborate to guide effective priority-setting to conserve the most irreplaceable components of biodiversity upon which humanity depends.

zoology↗

bioRxiv2022

Predicting catchment suitability for biodiversity at national scales

Biomonitoring of water quality and catchment management are often disconnected, due to mismatching scales. Great effort and money is spent each year on routine reach-scale surveying across many sites, particularly in the UK, and typically with a focus on pre-defined indicators of organic pollution to compare observed vs expected subsets of common macroinvertebrate indicator species. Threatened species are often ignored due to their rarity as are many invasive species, which are seen as undesirable even though they are increasingly common in freshwaters, especially in urban ecosystems. However, these taxa are monitored separately for reasons related to biodiversity concerns rather than for gauging water quality. Repurposing such monitoring data could therefore provide important new biomonitoring tools that can help catchment managers to directly link the water quality that they aim to control with the biodiversity that they are trying to protect. Here we used the England Non-Native and Rare/Protected species records that track these two groups of species as a proof-of-concept for linking catchment scale management of freshwater ecosystems and biodiversity to a range of potential drivers across England. We used national land use (Centre for Ecology and Hydrology land cover map) and water quality indicator (Environment Agency water quality data archive) datasets to predict the presence or absence of 48 focal threatened or invasive species of concern routinely sampled by the English Environment Agency at catchment scale, with a median accuracy of 0.81 area under the receiver operating characteristic curve. A variety of water quality indicators and land-use types were useful in predictions, highlighting that future biomonitoring schemes could use such complementary measures to capture a wider spectrum of drivers and responses. In particular, the percentage of a catchment covered by freshwater was the single most important metric, reinforcing the need for space/habitat to support biodiversity. We show how our method could inform new catchment management approaches, by highlighting how key relationships can be identified and how to understand, visualise and prioritise catchments that are most suitable for restorations or water quality interventions. The scale of this work, in terms of number of species, drivers and locations, represents a step towards a new approach to catchment management that enables managers to link drivers they can control (water quality and land use) to the biota they are trying to protect (biodiversity).

ecology↗

bioRxiv2021

The abiotic and biotic environment together predict plant, mammal, and bird diversity and turnover across the United States

The distribution of taxonomic, phylogenetic, and functional biodiversity results from a combination of abiotic and biotic drivers which are scale dependent. Parsing the relative influence of these drivers is critical to understanding the processes underlying species assembly and generating predictions of biodiversity across taxonomic groups and for novel sites. However, doing so requires data that capture a spatial extent large enough to reflect broad-scale dynamics such as speciation and biogeography, and a spatial grain fine enough to detect local-scale dynamics like environmental filtering and biotic interactions. We used species inventories of vascular plants, birds, and mammals collected by the U.S. National Ecological Observatory Network (NEON) at 38 terrestrial field sites, to explore the processes underlying taxonomic, phylogenetic, and functional diversity and turnover. We found that, for both species richness (alpha-diversity) and turnover (beta-diversity), taxonomic, phylogenetic, and functional diversity are weak proxies for one-another, and thus may capture different species assembly processes. All diversity metrics were best predicted by a combination of abiotic and biotic variables. Taxonomic and phylogenetic richness tended to be higher at warmer, wetter sites, reflecting the role energy inputs play in driving broad-scale diversity. However, plant diversity was negatively correlated with bird phylogenetic and mammal functional diversity, implying trait conservation in plant communities may limit niche availability for consumer species. Equally, turnover in bird and mammal species across sites were associated with plant turnover. That the biodiversity of one taxon is predictive of another across these North American sites, even when controlling for environment, supports a role for the cross-clade biotic environment in driving species assembly.

ecology↗

bioRxiv2021

Disorder or a new order: how climate change affects phenological variability

Advancing spring phenology is a well-documented consequence of anthropogenic climate change, but it is not well understood how climate change will affect the variability of phenology year-to-year. Species phenological timings reflect adaptation to a broad suite of abiotic needs (e.g. thermal energy) and biotic interactions (e.g. predation and pollination), and changes in patterns of variability may disrupt those adaptations and interactions. Here, we present a geographically and taxonomically broad analysis of phenological shifts, temperature sensitivity, and changes in inter-annual variance encompassing nearly 10,000 long-term phenology time-series representing over 1,000 species across much of the northern hemisphere. We show that early-season species in colder and less seasonal regions were the most sensitive to temperature change and had the least variable phenologies. The timings of leaf-out, flowering, insect first-occurrence, and bird arrival have all shifted earlier and tend to be less variable in warmer years. This has led leaf-out and flower phenology to become moderately but significantly less variable over time. These simultaneous changes in phenological averages and the variation around them have the potential to influence mismatches among interacting species that are difficult to anticipate if shifts in average are studied in isolation.

ecology↗