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1. Foredune‐forming grass and plant diversity show contrasting responses along the southeastern United States coast after hurricane disturbance

   https://doi.org/10.1111/jvs.13230  

   De Battisti, Davide ; Angelini, Christine ; Joyce, Matthew ; Crotty, Sinead ; Fairchild, Tom P. ; Fischman, Hallie S. ; Griffin, John N. ( January 2024 , Journal of Vegetation Science)

   Latitudinal gradients in plant communities are well studied, yet how these fundamental ecological patterns influence ecosystem recovery after extreme weather events remains largely unknown. In coastal foredunes, we investigated how the cover of a key dune‐building grass (Uniola paniculata), vegetation diversity and vegetation cover vary along a short latitudinal gradient during recovery from hurricane disturbance.

   Southeastern USA.

   We surveyed 24 sites, from central Florida to north Georgia (>400 km), four times over 18 months. General linear mixed‐effect models were used to unravel patterns of vegetation responses across latitude.

   Vegetation properties showed countervailing patterns across the latitudinal gradient. While vegetation richness, functional diversity and total cover generally declined,Uniolacover increased with increasing latitude. Further, the latitude–richness relationship strengthened while the latitude–functional diversity relationship was invariant with increasing time since the hurricane disturbance. Meanwhile, the latitude–Uniolaassociation was seasonally dependent and strongest in the summer. Latitude also influenced diversity–cover relationships: vegetation cover was positively related to species richness at lower latitudes, while it was positively associated with functional diversity only at northern sites. We found no relationship between species richness or functional diversity and increases in cover between time steps; however, recruitment of new species and functional groups was associated with increases in vegetation cover between time steps at northern sites.

   Our study highlights the temporal dynamism and contrasting patterns along latitudinal gradients exhibited by key engineering species and overall plant diversity in foredunes — a crucial line of coastal protection — exposed to hurricane disturbances. These results suggest a need for greater integration of latitudinal and diversity effects into our understanding of coastal dune resilience. They also highlight the potential benefits of enhancing dune plant biodiversity, particularly in areas where the dune‐building grasses that are classically employed in restoration (e.g.,Uniola) are unfavoured, to accelerate the re‐establishment of well‐vegetated dunes.

    

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2. A graphical null model for scaling biodiversity–ecosystem functioning relationships

   https://doi.org/10.1111/1365-2745.13578  

   Barry, Kathryn E. ; Pinter, Gabriella A. ; Strini, Joseph W. ; Yang, Karrisa ; Lauko, Istvan G. ; Schnitzer, Stefan A. ; Clark, Adam T. ; Cowles, Jane ; Mori, Akira S. ; Williams, Laura ; et al ( January 2021 , Journal of Ecology)

   Global biodiversity is declining at rates faster than at any other point in human history. Experimental manipulations at small spatial scales have demonstrated that communities with fewer species consistently produce less biomass than higher diversity communities. Understanding the consequences of the global extinction crisis for ecosystem functioning requires understanding how local experimental results are likely to change with increasing spatial and temporal scales and from experiments to naturally assembled systems.

   Scaling across time and space in a changing world requires baseline predictions. Here, we provide a graphical null model for area scaling of biodiversity–ecosystem functioning relationships using observed macroecological patterns: the species–area curve and the biomass–area curve. We use species–area and biomass–area curves to predict how species richness–biomass relationships are likely to change with increasing sampling extent. We then validate these predictions with data from two naturally assembled ecosystems: a Minnesota savanna and a Panamanian tropical dry forest.

   Our graphical null model predicts that biodiversity–ecosystem functioning relationships are scale‐dependent. However, we note two important caveats. First, our results indicate an apparent contradiction between predictions based on measurements in biodiversity–ecosystem functioning experiments and from scaling theory. When ecosystem functioning is measured as per unit area (e.g. biomass per m²), as is common in biodiversity–ecosystem functioning experiments, the slope of the biodiversity ecosystem functioning relationship should decrease with increasing scale. Alternatively, when ecosystem functioning is not measured per unit area (e.g. summed total biomass), as is common in scaling studies, the slope of the biodiversity–ecosystem functioning relationship should increase with increasing spatial scale. Second, the underlying macroecological patterns of biodiversity experiments are predictably different from some naturally assembled systems. These differences between the underlying patterns of experiments and naturally assembled systems may enable us to better understand when patterns from biodiversity–ecosystem functioning experiments will be valid in naturally assembled systems.

   Synthesis. This paper provides a simple graphical null model that can be extended to any relationship between biodiversity and any ecosystem functioning across space or time. Furthermore, these predictions provide crucial insights into how and when we may be able to extend results from small‐scale biodiversity experiments to naturally assembled regional and global ecosystems where biodiversity is changing.

    

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3. Vertical stratification patterns of tropical forest vertebrates: a meta‐analysis

   https://doi.org/10.1111/brv.12896  

   Basham, Edmund W. ; Baecher, J. Alex ; Klinges, David H. ; Scheffers, Brett R. ( September 2022 , Biological Reviews)

   Tropical forests harbour the highest levels of terrestrial biodiversity and represent some of the most complex ecosystems on Earth, with a significant portion of this diversity above ground. Although the vertical dimension is a central aspect of the ecology of forest communities, there is little consensus as to prominence, evenness, and consistency of community‐level stratification from ground to canopy. Here, we gather the results of 62 studies across the tropics to synthesise and assess broad patterns of vertical stratification of abundance and richness in vertebrates, the best studied taxonomic group for which results have not been collated previously. Our review of the literature yielded sufficient data for bats, small mammals, birds and amphibians. We show that variation in the stratification of abundance and richness exists within and among all taxa considered. Bat richness stratification was variable among studies, although bat abundance was weighted towards the canopy. Both bird richness and abundance stratification were variable, with no overriding pattern. On the contrary, both amphibians and small mammals showed consistent patterns of decline in abundance and richness towards the canopy. We descriptively characterise research trends in drivers of stratification cited or investigated within studies, finding local habitat structure and food distribution/foraging to be the most commonly attributed drivers. Further, we analyse the influence of macroecological variables on stratification patterns, finding latitude and elevation to be key predictors of bird stratification in particular. Prominent differences among taxa are likely due to taxon‐specific interactions with local drivers such as vertical habitat structure, food distribution, and vertical climate gradients, which may vary considerably across macroecological gradients such as elevation and biogeographic realm. Our study showcases the complexity with which animal communities organise within tropical forest ecosystems, while demonstrating the canopy as a critical niche space for tropical vertebrates, thereby highlighting the inherent vulnerability of tropical vertebrate communities to forest loss and canopy disturbance. We recognise that analyses were constrained due to variation in study designs and methods which produced a variety of abundance and richness metrics recorded across different arrangements of vertical strata. We therefore suggest the application of best practices for data reporting and highlight the significant effort required to fill research gaps in terms of under‐sampled regions, taxa, and environments.

    

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4. Does functional redundancy affect ecological stability and resilience? A review and meta‐analysis

   https://doi.org/10.1002/ecs2.3184  

   Biggs, Christopher R. ; Yeager, Lauren A. ; Bolser, Derek G. ; Bonsell, Christina ; Dichiera, Angelina M. ; Hou, Zhenxin ; Keyser, Spencer R. ; Khursigara, Alexis J. ; Lu, Kaijun ; Muth, Arley F. ; et al ( July 2020 , Ecosphere)

   In light of rapid shifts in biodiversity associated with human impacts, there is an urgent need to understand how changing patterns in biodiversity impact ecosystem function. Functional redundancy is hypothesized to promote ecological resilience and stability, as ecosystem function of communities with more redundant species (those that perform similar functions) should be buffered against the loss of individual species. While functional redundancy is being increasingly quantified, few studies have linked differences in redundancy across communities to ecological outcomes. We conducted a review and meta‐analysis to determine whether empirical evidence supports the asserted link between functional redundancy and ecosystem stability and resilience. We reviewed 423 research articles and assembled a data set of 32 studies from 15 articles across aquatic and terrestrial ecosystems. Overall, the mean correlation between functional redundancy and ecological stability/resilience was positive. The mean positive effect of functional redundancy was greater for studies in which redundancy was measured as species richness within functional groups (vs. metrics independent of species richness), but species richness itself was not correlated with effect size. The results of this meta‐analysis indicate that functional redundancy may positively affect community stability and resilience to disturbance, but more empirical work is needed including more experimental studies, partitioning of richness and redundancy effects, and links to ecosystem functions.

    

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5. Contrasting effects of plant diversity on β‐ and γ‐diversity of grassland invertebrates

   https://doi.org/10.1002/ecy.3057  

   Ebeling, A. ; Lind, E. W. ; Meyer, S. T. ; Barnes, A. D. ; Borer, E. T. ; Eisenhauer, N. ; Weisser, W. W. ( April 2020 , Ecology)

   The diversity of primary producers strongly affects the structure and diversity of species assemblages at other trophic levels. However, limited knowledge exists of how plant diversity effects at small spatial scales propagate to consumer communities at larger spatial scales. We assessed arthropod community β and γ‐diversity in response to experimentally manipulated plant community richness in two long‐term grassland biodiversity experiments (Jena, Germany and Cedar Creek, USA) replicated over two years. We calculated arthropod species turnover among all plot combinations (β‐diversity), and accumulated number of arthropod species occurring on (1) all pairwise plot combinations and (2) 40 randomly selected six‐plot combinations (γ‐diversity). The components of arthropod diversity were tested against two measures of plant diversity, namely average plant α‐diversity () and the average difference in plant α‐diversity between plots (ΔPSR). Whereas points to the overall importance of plant α‐diversity for arthropod community turnover and diversity on a larger scale, ΔPSR represents the role of habitat heterogeneity. We demonstrate that arthropod γ‐diversity is supported by high, homogeneous plant α‐diversity, despite lower arthropod β‐diversity among high‐ compared to low‐diversity plant communities. We also show that, in six‐plot combinations, average plant α‐diversity has a positive influence on arthropod γ‐diversity only when homogeneity in plant α‐diversity is also high. Varying heterogeneity in six‐plot combinations showed that combinations consisting solely of plots with an intermediate level of plant α‐diversity support a higher number of arthropod species compared to combinations that contain a mix of high‐ and low‐diversity plots. In fact, equal levels of arthropod diversity were found for six‐plot combinations with only intermediate or high plant α‐diversity, due to saturating benefits of local and larger‐scale plant diversity for higher trophic levels. Our results, alongside those of recent observational studies, strongly suggest that maintaining high α‐diversity in plant communities is important for conserving multiple components of arthropod diversity. As arthropods carry out a range of essential ecosystem functions, such as pollination and natural pest‐control, our findings provide crucial insight for effective planning of human‐dominated landscapes to maximize both ecological and economic benefits in grassland systems.

    

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