Biogeographic Differences Research Articles

Baseline for marine cave monitoring strategies in the Alboran Sea using modified Cave Ecosystem-Based Quality Index (CavEBQI)

Marine caves constitute vulnerable habitats with unique and diverse biocoenoses. Monitoring these habitats is still challenging, which hinders the ability to evaluate global and local pressures that threatens their ecological value. In this study, ecological quality is estimated in twenty-one marine caves distributed along the northern and southern coasts of the Alboran Sea, a highly understudied area regarding marine caves. For that purpose, adjustments on the original Cave Ecosystem Based Quality Index (CavEBQI) are suggested in order to efficiently estimate the ecological quality of marine caves. Several methodological aspects regarding the assessment of biotic coverage, the visual census of motile fauna and the plasticity of the index usability were evaluated. Ecological quality of marine caves was in average “good” although it ranged between “poor”, “moderate” and “good” depending on the features of each cave. This study emphasizes the importance of adapting biotic indicators to biogeographical differences and technological advancements.

Biogeographical Variation in Termite Distributions Alters Global Deadwood Decay

ABSTRACTAimTermites are a crucial group of macroinvertebrates regulating rates of deadwood decomposition across tropical and subtropical regions. When examining global patterns of deadwood decay, termites are treated as a homogenous group. There exist key biogeographical differences in termite distribution. One such clear distinction is the distribution of fungus‐growing termites (FGT, subfamily Macrotermitinae). Considering that climate will have shaped termite distribution and ecosystem processes, we evaluate the roles of termite distribution (presence of FGT) and climate (aridity) on global patterns in deadwood decay.LocationBetween 46° N‐43° S and 175° E‐85° W.Time PeriodPresent (between 2016 and 2021).Major Taxa StudiedTermites (Blattodea: Termitoidae).MethodsWe add salient data to an existing global dataset on deadwood decomposition, including new data from five existing sites and seven additional African sites. We analyse a dataset spanning six continents, 16 countries and 102 experimental sites. Firstly, we evaluate climatic differences (mean annual temperature, mean annual precipitation and mean annual aridity) between sites with and without FGT. Secondly, using aridity as a single comparative climate metric between sites that accounts for temperature and precipitation differences, we examine the interaction between FGT and aridity on global patterns of termite deadwood discovery and decay through multivariate logistic and linear regressions.ResultsTermite‐driven decay and wood discovery increased with aridity; however, responses differed between FGT and NFGT sites. Wood discovery increased with aridity in FGT sites only, suggesting a greater role of FGT to deadwood decay in arid environments. On average, both termite discovery and decay of deadwood were approximately four times greater in regions with FGT compared with regions without FGT.Main ConclusionsTermite discovery and decay of deadwood is climate dependent, and higher decay may be through greater discovery of deadwood in FGT sites. Inclusion of biogeographical differences in termite distribution could potentially alter current and future global estimates of deadwood turnover.

Global Phylogeography and Microdiversity of the Marine Diazotrophic Cyanobacteria Trichodesmium and UCYN-A.

Cyanobacterial diazotrophs, specifically the genera Trichodesmium and UCYN-A, play a pivotal role in marine nitrogen cycling through their capacity for nitrogen fixation. Despite their global distribution, the microdiversity and environmental drivers of these diazotrophs remain underexplored. This study provides a comprehensive analysis of the global diversity and distribution of Trichodesmium and UCYN-A using the nitrogenase gene ( nifH ) as a genetic marker. We sequenced 954 samples from the Pacific, Atlantic, and Indian Oceans as part of the Bio-GO-SHIP project. Our results reveal significant phylogenetic and biogeographic differences between and within the two genera. Trichodesmium exhibited greater microdiversity compared to UCYN-A, with clades showing region-specific distribution. Trichodesmium clades were primarily influenced by temperature and nutrient availability, and particularly frequent in regions of phosphorus stress. In contrast UCYN-A was found in regions of iron stress. UCYN-A clades demonstrated a more homogeneous distributions, with a single sequencing variant within the UCYN-A1 clade dominating across varied environments. The biogeographic patterns and environmental correlations of Trichodesmium and UCYN-A highlight the role of microdiversity in their ecological adaptation and reflect their different ecological strategies. This study underscores the importance of characterizing the global patterns of fine-scale genetic diversity to better understand the functional roles and distribution of marine nitrogen-fixing cyanobacteria.

Regional-scale biogeographical patterns of soil extracellular enzyme activities across eight Chinese fir plantation locations

Chinese fir (Cunninghamia lanceolata) is the most important conifer tree species in plantations in subtropical China. Soil extracellular enzyme activities (EEAs) play key roles in mediating multiple forest ecosystem functions, such as organic matter decomposition, nutrient cycling, and plant productivity. In this study, the activities of five soil extracellular enzymes and their stoichiometric (EES) features were investigated at eight Chinese fir plantation locations. The results showed that the soil EEAs exhibited distinct biogeographic differences and were primarily affected by the spatial heterogeneity of soil nutrients. We found that the soil EES was strongly influenced by soil pH and mean annual temperature. Moreover, soil properties were found to be more important than climatic factors in influencing changes in soil microbial nutrient restrictions based on vector length (0.43 vs. −0.1). Random forest analysis indicated that changes in microbial nitrogen (N) and phosphorus (P) limitations were mainly affected by soil NO3−-N and dissolved organic carbon (DOC), whereas soil microbial C limitation was largely influenced by pH, DOC, and total C content. This study sheds light on how soil and climatic factors affect soil EES in subtropical Chinese fir plantation ecosystems and provides useful insights for the development of management strategies to improve the productivity of Chinese fir forests.

Current status and prognosis of Raphidiopsis raciborskii distribution in Bulgaria as part of the southeastern region of Europe

The cyanobacterial species Raphidiopsis raciborskii (Wołoszyńska) Aguilera et al. has a high invasiveness potential, which in less than a century leads to its cosmopolitan spread. In the temperate climate of Europe, R. raciborskii has been reported in many countries, but there is still a lack of detailed information about the current status of its distribution in lakes of Bulgaria, as a part of the southeastern range of its spread in Europe. We investigated the distribution of the species using data on the phytoplankton of 122 lakes surveyed during 13-years period (2009–2022). The species was found in 33 lakes (up to 324 m asl), and 14 new localities were registered during the studied period. The results reveal that the number of lakes with the presence of R. raciborskii (27 % of all research lakes) and its contribution to the total phytoplankton biomass, has increased significantly over the last decade. The species has successfully adapted and dominated the phytoplankton in 9 lakes, forming a bloom in 8 of them. The dominant position of R. raciborskii causes loss of species and functional diversity of phytoplankton and displaces the native bloom-forming cyanobacteria.Lakes with and without the species were compared based on the available data on bioclimatic and local environmental variables. Statistically significant differences were established with respect to water transparency, conductivity, maximum depth and maximum air temperature in the warmest month. Species distribution models (SDMs) were used to identify lakes in high risk of future invasion by R. raciborskii. The results of the SDMs implementation confirmed the high maximum air temperature and low water transparency to be important predictors of the occurrence of R. raciborskii in freshwater lakes in Bulgaria. In the areas with high summer temperatures the most suitable for R. raciborskii development were found to be shallow polymictic or medium deep lakes with small surface area and low water transparency. In areas with a suitable climate, the large, deep reservoirs with high transparency as well as macrophyte dominated lakes have a low probability of occurrence of R. raciborskii. Future colonization of lakes above 500 m asl (but most likely below 700 m asl) is also possible, especially in the conditions of global warming. SDMs account for climatic and biogeographic differences of lakes and could help in elucidating the underlying factors that control the occurrence and adaptation of R. raciborskii in a given area.

Current Forest–Savanna Transition in Northern South America Departs from Typical Climatic Thresholds

The forest–savanna transition is the most widespread ecotone in the tropics, with important ecological, climatic, and biogeochemical implications at local to global scales. However, the factors and mechanisms that control this transition vary among continents and regions. Here, we analyzed which factors best explain the transition in northern South America (Llanos ecoregion and northwestern Amazon), where common thresholds on typical environmental factors (for example, mean annual precipitation (MAP), wet season precipitation) fail to predict it. For instance, savannas in the Llanos occur at MAP levels (> 1500 mm) which are typical of forests in other tropical regions. We examined the transition’s climate features, soils, and disturbance (fire frequency) spaces using remotely sensed data. We used logistic generalized linear models to assess the effect of seasonal (season length) and intra-seasonal (daily precipitation frequency and intensity) precipitation metrics during the dry season, soil silt content, and fire frequency, on the transition using canopy cover, tree cover, and the maximum Plant Area Volume Density as vegetation structure descriptor variables. Fire frequency and precipitation frequency were the most important variables explaining the transition. Although most fires occur in savannas, we found that a significant percentage of savanna pixels (46%) had no fires. This study indicates that the transition should be characterized regionally in response to biogeographic differences (for example, climatic space) among regions and continents. Our results highlight the importance of fire frequency and intra-seasonal precipitation in determining the transition in northern South America. Furthermore, future studies should consider regional differences in the climatic space of forest and savanna to improve projections of global change impacts on these highly diverse ecosystems.

Assembly Processes and Biogeographical Characteristics of Soil Bacterial Sub-communities of Different Habitats in Urban Green Spaces.

The process of urbanization is one of the most important human-driven activities that reshape the natural distribution of soil microorganisms. However, it is still unclear about the effects of urbanization on the different taxonomic soil bacterial community dynamics. In this study, we collected soil samples from highly urbanized the regions of Yangtze River Delta, Beijing-Tianjin-Hebei in China, to explore the bio-geographic patterns, assembly processes, and symbiotic patterns of abundant, moderate, and rare bacterial communities. We found that the number of moderate and rare taxa species were lower than that of abundant taxa, but their α-diversity index was higher than abundant taxa. Proteobacteria, Acidobacteria, Actinobacteria, Bacterioidetes, and Chloroflexi were the dominant phylum across all three sub-communities. And the β-diversity value of rare taxa was significantly higher than those of moderate and abundant taxa. Abundant, moderate, and rare sub-communities showed a weak distance-decay relationship, and the moderate taxa had the highest turnover rate of microbial geography in the context of urbanization. Diffusion limitation was the dominant process of soil bacterial community assembly. The co-occurrence networks of abundant, moderate, and rare taxa were dominated by positive correlations. The network of moderate taxa had the highest modularity, followed by abundant taxa. The main functions of the abundant, moderate, and rare taxa were related to Chemoheterotrophy and N transformations. Redundancy analysis showed that the dispersal limitation, climate, and soil properties were the main factors dominating bio-geographic differences in soil bacterial community diversity. We conclude that human-dominated urbanization processes have generated more uncertain survival pressures on soil bacteria, which resulted in a stronger linkage but weak bio-geographic variation for soil bacteria. In the future urban planning process, we suggest that such maintenance of native vegetation and soil types should be considered to maintain the long-term stability of local microbial ecosystem functions.

Thermal sensitivity of metabolic rate mirrors biogeographic differences between teleosts and elasmobranchs

Environmental temperature affects physiological functions, representing a barrier for the range expansions of ectothermic species. To understand the link between thermal physiology and biogeography, a key question is whether among-species thermal sensitivity of metabolic rates is mechanistically constrained or buffered through physiological remodeling over evolutionary time. The former conception, the Universal Temperature Dependence hypothesis, predicts similar among- and within-species thermal sensitivity. The latter conception, the Metabolic Cold Adaptation hypothesis, predicts lower among-species thermal sensitivity than within-species sensitivity. Previous studies that tested these hypotheses for fishes overwhelmingly investigated teleosts with elasmobranchs understudied. Here, we show that among-species thermal sensitivity of resting metabolic rates is lower than within-species sensitivity in teleosts but not in elasmobranchs. Further, species richness declines with latitude more rapidly in elasmobranchs than in teleosts. Metabolic Cold Adaptation exhibited by teleosts might underpin their high diversity at high latitudes, whereas the inflexible thermal sensitivity approximated by Universal Temperature Dependence of elasmobranchs might explain their low diversity at high latitudes.

The Habitat Persistence Hypothesis: a new perspective on the distribution of coral-reef organisms

We propose and define the “Habitat Persistence Hypothesis” (HPH) to explain the biogeographical distributions of organisms (especially fishes, invertebrates and algae) inhabiting tropical coral reefs. Both published and unpublished sources indicate that species occurringon deep coral reefs show higher rates of endemism and a less apparent biodiversity gradient across the Pacific Ocean than their counterparts inhabiting shallow coral reefs. The HPH accounts for these biogeographical differences by stipulating that deep reefs are relatively unaffected by sea level changes associated with glacial-interglacial cycles. Shallow-reef habitats may persist across sea level changes in regions with sloped bathymetry (e.g., continental regions and large islands), but are largely extirpated in regions with steep bathymetry (e.g., coral atolls). The HPH suggests that regions with habitat persistence are characterized by higher rates of endemism, and that patterns of attenuating diversity with increasing distance from centers of species richness are shaped by relatively recent recolonization of less persistent habitats from regions with greater habitat persistence. Whereas most existing hypotheses that attempt to explain biogeographical patterns observed on coral reefs (especially in the Indo-Pacific region) relyon observations limited to shallow (<30 m) coral-reef habitat and invoke processes operating on speciation time-scales (107 – 108 yr), the HPH incorporates patterns observed within the remaining 80% of coral-reef habitat (30 – 150 m) and invokes processes operating on time scales associated with sea-level changes (105 – 106 yr). The HPH posits seven specific predictions about coral-reef biogeography that can be directly tested to distinguish it from previous hypotheses. Our intention is to describe the rationale and qualitative support for the HPH with the hope of providing a framework for accumulating sufficient quantitative data to test the predictions, which we anticipate will require decades of robust field surveys.

A Review of the Ecological and Biogeographic Differences of Amazonian Floodplain Forests

Amazonian floodplain forests along large rivers consist of two distinct floras that are traced to their differentiated sediment- and nutrient-rich (várzea) or sediment- and nutrient-poor (igapó) environments. While tree species in both ecosystems have adapted to seasonal floods that may last up to 270–300 days year−1, ecosystem fertility, hydrogeomorphic disturbance regimes, water shortage and drought, fire, and even specific microclimates are distinct between both ecosystems and largely explain the differences in forest productivity and taxonomic composition and diversity. Here, we review existing knowledge about the influence of these environmental factors on the tree flora of both ecosystems, compare species composition and diversity between central Amazonian várzeas and igapós, and show that both ecosystems track distinct species life-history traits. The ecosystem-level and taxonomic differences also largely explain the biogeographic connections of várzeas and igapós to other Amazonian and extra-Amazonian ecosystems. We highlight the major evolutionary force of large-river wetlands for Amazonian tree diversity and explore the scenarios by which the large number of Amazonian floodplain specialist tree species might even contribute to the gamma diversity of the Amazon by generating new species. Finally, we call attention to the urgent need of an improved conservation of Amazonian várzea and igapó ecosystems and their tree species.

The macroecology of community energy use in terrestrial vertebrates

Energy is a fundamental macroecological property as it governs all ecological processes and interactions. Understanding variation in community energy use and its correlations is crucial to knowing how communities function across the globe. As an organism’s metabolic rate equates to its rate of energy flow, individual rates can predict community-level functioning. Here, daily rates of community energy flow are calculated for 118 bat, 109 bird, and 196 non-volant small mammal inventories from around the world. These were scaled up from individual metabolic rates that were obtained for the 416 bat, 1880 bird, and 562 small mammal species present in the samples. While controlling for spatial autocorrelation, rates were contrasted and compared to various ecological, environmental, geographic, and anthropogenic variables, using a method of sequential regression that renders the variables orthogonal to each other, thus addressing the issue of collinearity. In all groups, there is a strong positive correlation between community energy use and community mass, with biomass being the primary determinant of community energy flow. More surprisingly, there are strong biogeographic differences within and between groups. Bat communities have consistently higher rates of energy flow in the Neotropics, while small mammal communities have higher rates relative to mass in Holarctic realms. Investigations of individual-level patterns reveal that these differences are a direct result of contrasting patterns of abundance, average individual mass, and metabolic rates. These results indicate that community energy use is strongly linked to differences in ecology and evolutionary history within and among groups.

Ecoregion and community structure influences on the foliar elemental niche of balsam fir (Abies balsamea (L.) Mill.) and white birch (Betula papyrifera Marshall).

Changes in foliar elemental niche properties, defined by axes of carbon (C), nitrogen (N), and phosphorus (P) concentrations, reflect how species allocate resources under different environmental conditions. For instance, elemental niches may differ in response to large‐scale latitudinal temperature and precipitation regimes that occur between ecoregions and small‐scale differences in nutrient dynamics based on species co‐occurrences at a community level. At a species level, we compared foliar elemental niche hypervolumes for balsam fir (Abies balsamea (L.) Mill.) and white birch (Betula papyrifera Marshall) between a northern and southern ecoregion. At a community level, we grouped our focal species using plot data into conspecific (i.e., only one focal species is present) and heterospecific groups (i.e., both focal species are present) and compared their foliar elemental concentrations under these community conditions across, within, and between these ecoregions. Between ecoregions at the species and community level, we expected niche hypervolumes to be different and driven by regional biophysical effects on foliar N and P concentrations. At the community level, we expected niche hypervolume displacement and expansion patterns for fir and birch, respectively—patterns that reflect their resource strategy. At the species level, foliar elemental niche hypervolumes between ecoregions differed significantly for fir (F = 14.591, p‐value = .001) and birch (F = 75.998, p‐value = .001) with higher foliar N and P in the northern ecoregion. At the community level, across ecoregions, the foliar elemental niche hypervolume of birch differed significantly between heterospecific and conspecific groups (F = 4.075, p‐value = .021) but not for fir. However, both species displayed niche expansion patterns, indicated by niche hypervolume increases of 35.49% for fir and 68.92% for birch. Within the northern ecoregion, heterospecific conditions elicited niche expansion responses, indicated by niche hypervolume increases for fir of 29.04% and birch of 66.48%. In the southern ecoregion, we observed a contraction response for birch (niche hypervolume decreased by 3.66%) and no changes for fir niche hypervolume. Conspecific niche hypervolume comparisons between ecoregions yielded significant differences for fir and birch (F = 7.581, p‐value = .005 and F = 8.038, p‐value = .001) as did heterospecific comparisons (F = 6.943, p‐value = .004, and F = 68.702, p‐value = .001, respectively). Our results suggest species may exhibit biogeographical specific elemental niches—driven by biophysical differences such as those used to describe ecoregion characteristics. We also demonstrate how a species resource strategy may inform niche shift patterns in response to different community settings. Our study highlights how biogeographical differences may influence foliar elemental traits and how this may link to concepts of ecosystem and landscape functionality.

The smallest area shaped a big problem: a revision of the placement of the Ventania sky island in the biogeography of South America

AbstractThe placement of the southern border of the Neotropical region, called the Subtropical Line, is a long-lasting point of discussion. Its most debatable section runs around the Pampean province, where an isolated mountain system called Ventania has Andean connections surrounded by Neotropical biota. To answer where to place the Subtropical Line, a thorough revision of the biogeography of Ventania is needed. Thus, we characterized Ventania as an area of endemism and conducted a similitude analysis to compare it with surrounding systems using stenoic taxa. Then we compiled the disjunct distributions in Ventania and the phylogenetic information of its endemic taxa to know with which other areas it is related. We also compared the biogeographic differences with Tandilia, the nearest mountain system. We found that Ventania is a small but well-defined area of endemism mostly related to the Andean and South American Transition Zone (SATZ) provinces. Relatedness with the Pampean province is less than had been thought. We suggest that Ventania is a SATZ sky island province, and the smallest continental province of the world. The Subtropical Line should therefore be placed in the southern border of the Pampean province, with Ventania as a SATZ island inside the Neotropical region.

The EICA is dead? Long live the EICA!

An important hypothesis for how plants respond to introduction to new ranges is the evolution of increased competitive ability (EICA). EICA predicts that biogeographical release from natural enemies initiates a trade-off in which exotic species in non-native ranges become larger and more competitive, but invest less in consumer defences, relative to populations in native ranges. This trade-off is exceptionally complex because detecting concomitant biogeographical shifts in competitive ability and consumer defence depends upon which traits are targeted, how competition is measured, the defence chemicals quantified, whether defence chemicals do more than defend, whether 'herbivory' is artificial or natural, and where consumers fall on the generalist-specialist spectrum. Previous meta-analyses have successfully identified patterns but have yet to fully disentangle this complexity. We used meta-analysis to reevaluate traditional metrics used to test EICA theory and then expanded on these metrics by partitioning competitive effect and competitive tolerance measures and testing Leaf-Specific Mass in detail as a response trait. Unlike previous syntheses, our meta-analyses detected evidence consistent with the classic trade-off inherent to EICA. Plants from non-native ranges imposed greater competitive effects than plants from native ranges and were less quantitatively defended than plants from native ranges. Our results for defence were not based on complex leaf chemistry, but instead were estimated from tannins, toughness traits and primarily Leaf-Specific Mass. Species specificity occurred but did not influence the general patterns. As for all evidence for EICA-like trade-offs, we do not know if the biogeographical differences we found were caused by trade-offs per se, but they are consistent with predictions derived from the overarching hypothesis. Underestimating physical leaf structure may have contributed to two decades of tepid perspectives on the trade-offs fundamental to EICA.

Odonate Diversity Patterns in Italy Disclose Intricate Colonization Pathways.

Simple SummaryDuring the last Ice Age, most European animals retreated into southern refuges (mainly the Iberian, Italian, and Balkan peninsulas) from which they recolonized central and northern countries after deglaciation. These medio-European territories may have subsequently acted as secondary centers of southward dispersion for many species. Acting both as a refuge and as an area of colonization from adjacent territories, Italy was the theater of complex biogeographical histories, as illustrated by current distributional patterns of odonates (damselflies and dragonflies). These patterns are a result of historical factors and current ecological conditions. Odonates need freshwater for their development, and their richness in Italy decreases southwards, both because of a decrease in precipitation and because of increasing distance from the mainland (peninsula effect). Biogeographical composition of Italian regions is influenced by climate, geographical distances and historical factors. In particular, biogeographical similarities between Italian regions and adjacent areas revealed multiple colonization patterns. After serving as a glacial refuge from which odonates may have colonized medio-European areas, Italy was in turn subject to complex colonization processes, that made its fauna biogeographically very complex, albeit not particularly rich.As a natural bridge between Europe and Africa, Italy occupies a prominent position to understand the biogeography of Europe. The influence of climatic, spatial, and historical factors on current patterns of species richness and turnover (i.e., inter-regional biogeographical differences) has been analyzed for 88 species occurring in 17 Italian natural regions. Use of multimodel inference showed that odonate richness decreased southwards in response to decreasing rainfall, as expected for animals that depend on freshwater for their development. Use of Mantel tests indicated that patterns of inter-regional similarities were influenced by both climate and geographical distances. These patterns, as highlighted using Non-Metric Multidimensional Scaling, indicate a role for historical factors. Biogeographical similarities between Italian regions and adjacent areas revealed multiple colonization pathways. These results, coupled with the overall southward decrease in species richness, suggest that, after serving as a Pleistocene refuge from which odonates may have colonized medio-European areas, Italy was in turn subject to colonization from north to south. This resulted in Italian odonate fauna being less species rich compared to faunas in the medio-European territories, but also being biogeographically very complex.

Croatian freshwater bryoflora-diversity and distribution.

An extensive macrophyte field survey of running and standing waters was conducted from 2016 to 2021 at 786 sampling sites across Croatia as a part of the implementation of the Water Framework Directive. This survey is the first to present a comprehensive floristic catalogue of the freshwater bryoflora, along with an analysis of the distribution and diversity patterns on a national level. In all, 83 bryophyte species (68 mosses and 15 liverworts) were recorded in the 228 sites, with average species richness of 4.17 species per site. The most frequent species were Fontinalisantipyretica, Rhynchostegiumriparioides, Leptodictyumriparium and Cratoneuronfilicinum. The majority of the species encountered were rarely found, with over 70% of species recorded on less than 10 sampling sites and the majority of the species not being truly aquatic, rather being classified as facultative aquatics. The Dinaric Ecoregion, characterised by clean, cold, fast-flowing karstic rivers, especially in the Continental Subecoregion, supported higher freshwater bryophyte diversity than the lowland Pannonian Ecoregion, with mostly slow, eutrophic lowland watercourses with unstable sandy and gravelly alluvial sediments. Chorological comparison of Croatian eco- and subecoregions revealed the expected dominance of circumpolar and European elements, i.e. temperate chorotypes, as well as some biogeographical differences. The most frequent life forms were aquatic trailings and turfs. Amongst the recorded species, perennials and colonists were the most represented life strategies. The analysis of both the life-form and life-strategy spectra showed some differences amongst the Croatian regions, supporting the fact that the Dinaric Ecoregion provides more truly aquatic habitats and microhabitats suitable for the freshwater bryophytes, while in the Pannonian Ecoregion freshwater bryophytes dominantly inhabit the periodically submerged riparian zones, for example shaded lowland forest streams and rivulets or gently sloping margins of rivers and lakes.

Towards mapping biodiversity from above: Can fusing lidar and hyperspectral remote sensing predict taxonomic, functional, and phylogenetic tree diversity in temperate forests?

AbstractAimRapid global change is impacting the diversity of tree species and essential ecosystem functions and services of forests. It is therefore critical to understand and predict how the diversity of tree species is spatially distributed within and among forest biomes. Satellite remote sensing platforms have been used for decades to map forest structure and function but are limited in their capacity to monitor change by their relatively coarse spatial resolution and the complexity of scales at which different dimensions of biodiversity are observed in the field. Recently, airborne remote sensing platforms making use of passive high spectral resolution (i.e., hyperspectral) and active lidar data have been operationalized, providing an opportunity to disentangle how biodiversity patterns vary across space and time from field observations to larger scales. Most studies to date have focused on single sites and/or one sensor type; here we ask how multiple sensor types from the National Ecological Observatory Network’s Airborne Observation Platform (NEON AOP) perform across multiple sites in a single biome at the NEON field plot scale (i.e., 40 m × 40 m).LocationEastern USA.Time period2017–2018.Taxa studiedTrees.MethodsWith a fusion of hyperspectral and lidar data from the NEON AOP, we assess the ability of high resolution remotely sensed metrics to measure biodiversity variation across eastern US temperate forests. We examine how taxonomic, functional, and phylogenetic measures of alpha diversity vary spatially and assess to what degree remotely sensed metrics correlate with in situ biodiversity metrics.ResultsModels using estimates of forest function, canopy structure, and topographic diversity performed better than models containing each category alone. Our results show that canopy structural diversity, and not just spectral reflectance, is critical to predicting biodiversity.Main conclusionsWe found that an approach that jointly leverages spectral properties related to leaf and canopy functional traits and forest health, lidar derived estimates of forest structure, fine‐resolution topographic diversity, and careful consideration of biogeographical differences within and among biomes is needed to accurately map biodiversity variation from above.

Spatial phylogenetic patterns in the North American moss flora are shaped by history and climate

AbstractAimWe documented patterns of phylogenetic diversity (PD) and phylogenetic endemism (PE) in the moss flora of North America, determined how environmental variables explain these patterns, compared the patterns in mosses to known patterns in angiosperms and explored how patterns driven by sub‐clades might conflict with patterns driven by other sub‐clades.LocationNorth America north of Mexico.TaxonMosses (Bryophyta).MethodsA maximum‐likelihood tree inferred from publicly available sequence data and locality data from ca. 7.5 × 105 herbarium specimens were combined to build a dataset of 935 species (representing ca. 67% of the known moss flora). Spatial randomization procedures were used to find significance levels of PD and relative phylogenetic diversity (RPD) for the full dataset and three major sub‐clades, as well as to carry out a categorical analysis of Neo‐ and Paleo‐endemism (CANAPE). Range weighted turnover in both species and PE was used to identify phytogeographic regions across the continent. Ordinations of environmental data were used to determine the distribution of PD, RPD, and phytogeographic regions within environmental space. Results of this study were compared to known patterns of phylodiversity in angiosperms.ResultsPhylodiversity is distributed non‐randomly. Some patterns, for example, long branches in the southeastern US, are consistent with angiosperms; however, there are strong contrasts as well. Overall patterns of PD and RPD are strongly influenced by different phylogenetic scales within mosses, indicating that signal from one clade can obscure patterns in others. Three primary phytogeographic zones are defined by both differing geological histories and differing current abiotic conditions. Phytogeographic regions, PD, and RPD are all aligned with environmental variables.Main conclusionsThere is evidence for both ecological and historical factors in shaping the moss flora of North America, and biogeographic differences between angiosperms and mosses appear to align with important life‐history differences between the two groups.

Classification and distribution of evergreen broad-leaved forests in Jiangxi, East China

AbstractEvergreen broad-leaved forest (EBLF) is climax vegetation in East China, and Jiangxi Province is located at the center of EBLF. Although many phytosociological studies have provided detailed descriptions on this forest at local and regional scales, knowledge on the high-level classification of EBLF and factors controlling their tree species composition and distribution are still lacking. We aim at providing a high-level classification framework for EBLF in Jiangxi and exploring the roles of topographic and climatic factors in driving their distributions. We investigated 205 EBLF plots covering the main alliances across Jiangxi Province. Two-way indicator species analysis (TWINSPAN) and detrended correspondence analysis (DCA) were used to distinguish the EBLF types. Diagnostic and indicator species were detected. The nonparametric Kruskal–Wallis test was used to compare the differences between the groups of EBLFs. We also used redundancy analysis and variation partitioning to estimate the effects of climatic, geographical and topographical factors on the distribution of EBLFs in Jiangxi. The EBLFs in Jiangxi were classified into four types based on the diagnostic taxa and verified by TWINSPAN, i.e. lowland, ravine monsoon, montane typical and dwarf cloud EBLF types. These four EBLF types are associated with climatic and topographic conditions, and their distribution pattern reflects biogeographic differences. Our study provides an important basis for the syntaxonomic classification of EBLFs and further in-depth studies on humid EBLFs in East China. We also emphasize the importance of conservation practices to protect these forests as diversified Tertiary relict plants.

Genetic Differentiation among Subspecies of Banksia nivea (Proteaceae) Associated with Expansion and Habitat Specialization

Subspecies are traditionally defined using phenotypic differences associated with different geographical areas. Yet patterns of morphological and genetic variation may not coincide and thereby fail to reflect species’ evolutionary history. The division of the shrub Banksia nivea Labill. into one widespread (B. nivea subsp. nivea) and two geographically localized subspecies (B. nivea subsp. uliginosa (A.S. George) A.R. Mast & K.R. Thiele and B. nivea subsp. Morangup (M. Pieroni 94/2)) in south-west Australia has been based mainly on variation in leaf shape and pistil length, although flowering time and habitat differences are also evident, and subsp. uliginosa occurs on a different substrate. To assess the genetic divergence of B. nivea subspecies, we genotyped representatives from each subspecies for nuclear microsatellite and non-coding chloroplast sequence variation. We used distance and parsimony-based methods to assess genetic relatedness. Patterns were consistent with the existing taxonomy of subsp. nivea and uliginosa but not subsp. Morangup. Phylogenetic analyses revealed evidence for a more recent divergence of subsp. uliginosa associated with expansion from dryer sandy soils into the winter-wet ironstone soils in the southwest of Western Australia, consistent with progressive long-term climatic drying. Nuclear microsatellites showed low to moderate diversity, high population differentiation overall, and genetic structuring of subspecies in different biogeographical areas. We propose this pattern reflects the predicted impact of a patchy distribution, small populations, and restrictions to gene flow driven by both distance and biogeographic differences in subspecies’ habitats.