Shane A. Blowes's research while affiliated with Martin Luther University Halle-Wittenberg and other places

Publications (61)

Article
Ecological thresholds comprise relatively fast changes in ecological conditions, with respect to time or external drivers, and are an attractive concept in both scientific and policy arenas. However, there is considerable debate concerning the existence, underlying mechanisms, and generalizability of ecological thresholds across a range of ecologic...
Article
Full-text available
Patterns of biodiversity provide insights into the processes that shape biological communities around the world. Variation in species diversity along biogeographical or ecological gradients, such as latitude or precipitation, can be attributed to variation in different components of biodiversity: changes in the total abundance (i.e., more-individua...
Preprint
Earth’s biodiversity continues to change rapidly through the Anthropocene ¹ , including widespread reordering of species in space 2,3 and time 4,5 . A common expectation of this reordering is that the species composition of sites is becoming increasingly similar across space, known as biotic homogenization, due to anthropogenic pressures and invasi...
Article
Biodiversity metrics often integrate data on the presence and abundance of multiple species. Yet our understanding of covariation between changes to the numbers of individuals, the evenness of species relative abundances, and the total number of species remains limited. Using individual‐based rarefaction curves, we introduce a conceptual framework...
Preprint
Patterns of biodiversity provide insights into the processes that shape biological communities around the world. Variation in species diversity along biogeographical or ecological gradients, such as latitude or precipitation, can be attributed to variation in different components of biodiversity: changes in the total abundance (i.e. more-individual...
Preprint
Patterns of biodiversity provide insights into the processes that shape biological communities around the world. Variation in species diversity along biogeographical or ecological gradients, such as latitude or precipitation, can be attributed to variation in different components of biodiversity: changes in the total abundance (i.e. more-individual...
Article
Full-text available
Broad‐scale biodiversity monitoring relies, at least in part, on the efforts of citizen, or community, scientists. To ensure robust inferences from citizen science data, it is important to understand the spatial pattern of sampling effort by citizen scientists and how it deviates from an optimal pattern. Here, we develop a generalized workflow to e...
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Global change drivers such as anthropogenic nutrient inputs simultaneously alter biodiversity, species composition, and ecosystem functions such as above ground biomass. These changes are interconnected by complex feedbacks among extinction, invasion, and shifting relative abundance. Here, we use a novel temporal application of the Price equation t...
Preprint
Disturbances alter the diversity and composition of microbial communities, but whether microbiomes from different environments exhibit similar degrees of resistance or rates of recovery has not been evaluated. Here, we synthesized 86 time series of disturbed mammalian, aquatic, and soil microbiomes to examine how the recovery of microbial richness...
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The species composition of plant and animal assemblages across the globe has changed substantially over the past century. How do the dynamics of individual species cause this change? We classified species into seven unique categories of temporal dynamics based on the ordered sequence of presences and absences that each species contributes to an ass...
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Understanding how species are non‐randomly distributed in space and how the resulting spatial structure responds to ecological, biogeographic, and anthropogenic drivers is a critical piece of the biodiversity puzzle. However, most metrics that quantify the spatial structure of diversity (i.e., community differentiation), such as Whittaker’s β‐diver...
Preprint
Full-text available
Biodiversity metrics often integrate data on the presence and abundance of multiple species. Yet understanding covariation of changes to the numbers of individuals, the evenness of species’ relative abundances, and the total number of species remains limited. Using individual-based rarefaction curves, we introduce a conceptual framework to understa...
Article
Full-text available
Aim The island species–area relationship (ISAR) quantifies how the number of species increases as the area of an island or island-like habitat gets larger and is one of the most general patterns in ecology. However, studies that measure the ISAR often confound variation in sampling methodology and analyses, precluding appropriate syntheses of its u...
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While land use intensification is a major driver of biodiversity change in streams, the nature of such changes, and at which scales they occur, have not been synthesized. To synthesize how land use change has altered multiple components of stream biodiversity across scales, we compiled data from 37 studies where comparative data were available for...
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Full-text available
Structurally complex habitats tend to contain more species and higher total abundances than simple habitats. This ecological paradigm is grounded in first principles: species richness scales with area, and surface area and niche density increase with three-dimensional complexity. Here we present a geometric basis for surface habitats that unifies e...
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Full-text available
Seed dispersal limitation, which can be exacerbated by a number of anthropogenic causes, can result in local communities having fewer species than they might potentially support, representing a potential diversity deficit. The link between processes that shape natural variation in diversity, such as dispersal limitation, and the consequent effects...
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Full-text available
Disentangling the drivers of diversity gradients can be challenging. The Measurement of Biodiversity (MoB) framework decomposes scale‐dependent changes in species diversity into three components of community structure: the species abundance distribution (SAD), the total community abundance, and the within‐species spatial aggregation. Here we extend...
Article
Full-text available
Estimates of biodiversity change are essential for the management and conservation of ecosystems. Accurate estimates rely on selecting representative sites, but monitoring often focuses on sites of special interest. How such site-selection biases influence estimates of biodiversity change is largely unknown. Site-selection bias potentially occurs a...
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Full-text available
Although habitat loss is the predominant factor leading to biodiversity loss in the Anthropocene1,2, exactly how this loss manifests—and at which scales—remains a central debate3,4,5,6. The ‘passive sampling’ hypothesis suggests that species are lost in proportion to their abundance and distribution in the natural habitat7,8, whereas the ‘ecosystem...
Article
Aim The ‘abundant centre’ hypothesis states that species are more abundant at the centre of their range. However, several recent large‐scale studies have failed to find evidence for such a pattern. Here we used extensive global data of reef fishes to test the ‘abundant centre’ pattern, and to examine variation in the abundance patterns across speci...
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Full-text available
Climate change is reshaping global biodiversity as species respond to changing temperatures. However, the net effects of climate-driven species redistribution on local assemblage diversity remain unknown. Here, we relate trends in species richness and abundance from 21,500 terrestrial and marine assemblage time series across temperate regions (23.5...
Article
Land-use change and forest biodiversity Land-use change by humans, particularly forest loss, is influencing Earth's biodiversity through time. To assess the influence of forest loss on population and biodiversity change, Daskalova et al. integrated data from more than 6000 time series of species' abundance, richness, and composition in ecological a...
Preprint
Full-text available
Biodiversity is non-randomly distributed in space and understanding how spatial structure of species diversity responds to ecological, biogeographic and anthropogenic drivers is one of the major quests of modern ecology. However, metrics of community differentiation such as Whittaker’s beta-diversity fail to unambiguously capture species turnover w...
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Full-text available
Abstract Climate change and other anthropogenic drivers of biodiversity change are unequally distributed across the world. Overlap in the distributions of different drivers have important implications for biodiversity change attribution and the potential for interactive effects. However, the spatial relationships among different drivers and whether...
Preprint
Full-text available
Structurally complex habitats tend to contain more species and higher total abundances than simple habitats. This ecological paradigm is grounded in first principles: species richness scales with area, and surface area and niche density increase with three-dimensional complexity. Here we present a geometric basis for surface habitats that unifies e...
Article
Full-text available
Protected areas are central to biodiversity conservation. For marine fish, marine protected areas (MPAs) often harbour more individuals, especially of species targeted by fisheries. But precise pathways of biodiversity change remain unclear. For example, how local‐scale responses combine to affect regional biodiversity, important for managing spati...
Preprint
Full-text available
Climate change is reshaping global biodiversity as species respond to changing temperatures. However, the net effects of climate-driven species redistribution on local assemblage diversity remain unknown. Here, we relate trends in species richness and abundance from 21,500 terrestrial and marine assemblage time series across temperate regions (23.5...
Preprint
Full-text available
Disentangling the drivers of diversity gradients can be challenging. The Measurement of Biodiversity (MoB) framework decomposes changes in species diversity into three components of community structure: the species abundance distribution (SAD), the total community abundance, and the within-species spatial aggregation. Here we extend MoB from catego...
Article
Human activities are fundamentally altering biodiversity. Projections of declines at the global scale are contrasted by highly variable trends at local scales, suggesting that biodiversity change may be spatially structured. Here, we examined spatial variation in species richness and composition change using more than 50,000 biodiversity time serie...
Article
Habitat destruction is the single greatest anthropogenic threat to biodiversity. Decades of research on this issue have led to the accumulation of hundreds of data sets comparing species assemblages in larger, intact, habitats to smaller, more fragmented, habitats. Despite this, little synthesis or consensus has been achieved, primarily because of...
Article
Although evidence suggests that humans have elevated global extinction rates and lowered global species richness, species richness at scales smaller than the globe can increase, decrease or remain the same. However, the role of spatial scale is rarely considered as a modifier in driving how richness change unfolds. We first observed richness change...
Preprint
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Global assessments have highlighted land-use change as a key driver of biodiversity change. However, we lack real-world global-scale estimates of how habitat transformations such as forest loss and gain are reshaping biodiversity over time. Here, we quantify the influence of 150 years of forest cover change on populations and ecological assemblages...
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Full-text available
Human activities have fundamentally altered biodiversity. Extinction rates are elevated and model projections suggest drastic biodiversity declines. Yet, observed temporal trends in recent decades are highly variable, despite consistent change in species composition. Here, we uncover clear spatial patterns within this variation. We estimated trends...
Article
1.Little consensus has emerged regarding how proximate and ultimate drivers such as productivity, disturbance, and temperature may affect species richness and other aspects of biodiversity. Part of the confusion is that most studies examine species richness at a single spatial scale and ignore how the underlying components of species richness can v...
Preprint
Full-text available
Climate change and other anthropogenic drivers of biodiversity change are unequally distributed across the world. The geographic patterns of different drivers, and the spatial overlap among these drivers, have important implications for the direction and pace of biodiversity change, yet are not well documented. Moreover, it is unknown if the geogra...
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Full-text available
Because biodiversity is multidimensional and scale‐dependent, it is challenging to estimate its change. However, it is unclear (1) how much scale‐dependence matters for empirical studies, and (2) if it does matter, how exactly we should quantify biodiversity change. To address the first question, we analysed studies with comparisons among multiple...
Article
Macroecology is the study of the mechanisms underlying general patterns of ecology across scales. Research in microbial ecology and macroecology have long been detached. Here, we argue that it is time to bridge the gap, as they share a common currency of species and individuals, and a common goal of understanding the causes and consequences of chan...
Preprint
Full-text available
Little consensus has emerged regarding how proximate and ultimate drivers such as productivity, disturbance, and temperature may affect species richness and other aspects of biodiversity. Part of the confusion is that most studies examine species richness at a single spatial scale and ignore how the underlying components of species richness can var...
Preprint
Full-text available
Because biodiversity is multidimensional and scale-dependent, it is challenging to estimate its change. However, it is unclear (1) how much scale-dependence matters for empirical studies, and (2) if it does matter, how exactly we should quantify biodiversity change. To address the first question, we analyzed studies with comparisons among multiple...
Article
Full-text available
Motivation: The BioTIME database contains raw data on species identities and abundances in ecological assemblages through time. These data enable users to calculate temporal trends in biodiversity within and amongst assemblages using a broad range of metrics. BioTIME is being developed as a community-led open-source database of biodiversity time se...
Article
Full-text available
Motivation: The BioTIME database contains raw data on species identities and abundances in ecological assemblages through time. These data enable users to calculate temporal trends in biodiversity within and amongst assemblages using a broad range of metrics. BioTIME is being developed as a community-led open-source database of biodiversity time se...
Article
Full-text available
Motivation: The BioTIME database contains raw data on species identities and abundances in ecological assemblages through time. These data enable users to calculate temporal trends in biodiversity within and amongst assemblages using a broad range of metrics. BioTIME is being developed as a community led open-source database of biodiversity time se...
Article
Full-text available
Motivation: The BioTIME database contains raw data on species identities and abundances in ecological assemblages through time. These data enable users to calculate temporal trends in biodiversity within and amongst assemblages using a broad range of metrics. BioTIME is being developed as a community-led open-source database of biodiversity time se...
Article
Biodiversity varies from place to place due to environmental and historical factors. To improve our understanding of how history and the environment influence observed patterns, we need to address the limitations of the most commonly used biodiversity metric, species richness. Here, we show that scale-dependent dissections of species richness into...
Article
Full-text available
Functional responses describing how foraging rates change with respect to resource density are central to our understanding of interspecific interactions. Competitive interactions are an important determinant of foraging rates; however, the relationship between the exploitation and interference components of competition has received little empirica...
Article
The Mediterranean Sea is an invasion hotspot, with non-indigenous species suspected to be a major driver behind community changes. We used size spectra, a reliable index of food web structure, to examine how the influx of Red Sea fishes into the Mediterranean Sea has impacted the indigenous species community. This is the first attempt to use change...
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Full-text available
The dispersal potential of crown-of-thorns starfish (CoTS) larvae is important in understanding both the initiation and spread of population outbreaks, and is fundamentally dependent upon how long larvae can persist while still retaining the capacity to settle. This study quantified variation in larval survivorship and settlement rates for CoTS mai...
Article
Direct interference interactions between species are often mediated by aggression and related to resource use. Interference interactions are frequently asymmetric, whereby one species wins the majority of interactions; however, the effect of this asymmetry on the diet of subordinate species has not received the same attention as the impact of inter...
Preprint
Full-text available
The dispersal potential of crown-of-thorns starfish (CoTS) larvae is important in understanding both the initiation and spread of population outbreaks, and is fundamentally dependent upon how long larvae can persist while still retaining the capacity to settle. This study quantified variation in larval survivorship and settlement rates for CoTS mai...
Article
Full-text available
Extensive coral loss often leads to pronounced declines in the abundance of fishes, which are not necessarily limited to those fishes that are directly reliant on live coral for food or shelter. This study explored changes in the abundance of two non-corallivorous butterflyfish, Chaetadon auriga and Chaetodon vagabundus, during declines in coral co...
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Full-text available
Rare and cryptic species can be easily missed during ecological surveys of coral communities. This study reveals a disparity in the reported geographic range of a rare species, Echinomorpha nishihirai, between three different sources; none of which are wholly consistent with the available published occurrence records. Discrepancies in the species r...
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Full-text available
The global decline in biodiversity is causing increasing concern about the effects of biodiversity loss on ecosystem services such as productivity. Biodiversity has been hypothesised to be important in maintaining productivity of biological assemblages because niche complementarity and facilitation among the constituent species can result in more e...
Article
Abstract Interspecific competition mediates biodiversity maintenance and is an important selective pressure for evolution. Competition is often conceptualized as being exploitative (indirect) or involving direct interference. However, most empirical studies are phenomenological, focusing on quantifying effects of density manipulations, and most com...
Article
Two important processes determining the dynamics of spatially structured populations are dispersal and the spatial covariance of demographic fluctuations. Spatially explicit approaches to conservation, such as reserve networks, must consider the tension between these two processes and reach a balance between distances near enough to maintain connec...

Citations

... We also note that the volume of data available from citizen-science sources is rapidly growing, and not surprisingly, is being increasingly used for addressing a wide range of ecological-research questions (e.g., Callaghan et al., 2022). Still, data from large-scale citizen science typically present a number of challenges that may inhibit robust ecological inferences, including both species and spatial biases, variation in effort, and also variation in observer skills (Johnston et al., 2021). ...
... CSA is sensitive to sampling effort, species pool characteristics (e.g., size and species evenness, reflected by SAD), and their interactions, making it traditionally difficult to be compared without biases. β C is the CSA metric that is recently developed and derived from the rarefaction process based on sample coverage (a measure of sample completeness) and turns out to be unbiased by those factors (Engel et al., 2021). Therefore, it was applied for illustrating and comparing the metacommunity-level CSA pattern among forest types. ...
... Univariate metrics assessed were those known to have a major influence on local-scale biodiversity patterns (Blowes et al. 2022); i.e. (i) overall faunal numbers per unit area, (ii) observed numbers of taxa per unit area, N 0 [i.e. 'species density' sensu (Gotelli and Colwell 2001)], and (iii) relative evenness (= equitability) assessed as Pielou's J. Estimates of likely total number of taxa per unit area were obtained via Chao1 and ACE (abundancebased coverage estimation) values. ...
... Currently, land use intensification and deforestation are key processes that affect the composition of communities and reduce biodiversity in both terrestrial (Newbold et al. 2015) and freshwater ecosystems (Reid et al. 2019;Petsch et al. 2021a). In river catchments, the conversion of forests to agricultural and urban areas is related to major changes in stream conditions, including increased siltation, nutrient inputs, and light incidence; alteration of the flow regime; and reduced leaf litter input (Allan 2004). ...
... Our analysis suggests that such spatial patterns emerge from community dynamics operating differentially on islands of different sizes. This is not surprising since there is emerging evidence that ecological mechanisms affect islands of different sizes disproportionately (Gooriah et al. 2021). ...
... CoTS outbreaks associated with anthropogenic nutrient enrichment are now seen as one of the "signals" of partial eutrophication of the GBR [25,33]. Recently, refinements of the experiments have further supported the hypothesis [34,35,36] to an agreement that larval survivorship increases with increased food supply of phytoplankton biomass, represented by chlorophyll a concentrations of about 1 μgL -1 [35a,36] or at algal food densities above 1000 cells mL -1 [34] but with development is being inhibited at low chlorophyll a concentrations of 0.1 μgL -1 . Higher chlorophyll a concentrations close to 10 μgL -1 appear to retard development [35,36,37], indicating an optimum range of phytoplankton biomass or cell counts for larval survivorship. ...
... However, such approaches typically only offer qualitative insights because effect sizes from different diversity metrics are not quantitatively comparable (Dauby & Hardy, 2012). For example, one may find that more-individual effects seem to play a role for a gradient, but it usually remains unclear exactly what proportion of a diversity gradient can be attributed to variation in total abundance and associated passive sampling effects, and what percentage to changes in the regional SAD (but see McGlinn et al., 2019McGlinn et al., , 2021. ...
... Here, we show how the combination of rarefaction and accumulation curves can be used to disentangle changes in these three biodiversity components (Fig. 2). The key point is that the shape of the rarefaction curve only depends on the underlying SAD, but not on the spatial distribution, while the shape of the accumulation curve depends on both the SAD and the spatial distribution (McGlinn et al., 2018). First, we randomly removed 50% of all individuals. ...
... However, on a large scale a random and regular spatial distribution can happen. Random distribution occurs when sampling points are anywhere in the spatial site, that is, when there is no defined spatial pattern (Mentges et al., 2020). A regular distribution occurs when there is a "homogeneous" spacing between the sampling points, generating a sampling pattern of equal distance along the spatial gradient (Brooks et al., 2004). ...
... Due to the potential for morphological plasticity of marine taxa such as corals (Todd, 2008), assessing the discriminative power of 3D-morphological variables to distinguish species throughout