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opencc-zeroJun 2020View details →

Terrestrial acclimation and exercise lead to bone functional response in Polypterus pectoral fins

The ability of bones to sense and respond to mechanical loading is a central feature of vertebrate skeletons. However, the functional demands imposed on terrestrial and aquatic animals differ vastly. The pectoral girdle of the basal actinopterygian fish Polypterus senegalus was previously shown to exhibit plasticity following terrestrial acclimation, but the pectoral fin itself has yet to be examined. We investigated skeletal plasticity in the pectoral fins of P. senegalus after exposure to terrestrial loading. Juvenile fish were divided into three groups: a control group was kept under aquatic conditions without intervention, an exercised group was also kept in water but received daily exercise on land, and a terrestrial group was kept in a chronic semi-terrestrial condition. After 5 weeks, the pectoral fins were cleared and stained with Alcian Blue and Alizarin Red to visualize cartilage and bone, allowing measurements of bone length, bone width, ossification and curvature to be taken for the endochondral radial bones. Polypterus senegalus fin bones responded most strongly to chronic loading in the terrestrial condition. Fish that were reared in a terrestrial environment had significantly longer bones compared with those of aquatic controls, wider propterygia and metapterygia, and more ossified metapterygia and medial radials, and they showed changes in propterygial curvature. Exercised fish also had longer and more ossified medial radials compared with those of controls. Polypterus senegalus fin bones exhibit plasticity in response to novel terrestrial loading. Such plasticity could be relevant for transitions between water and land on evolutionary scales, but key differences between fish and tetrapod bone make direct comparisons challenging.

opencc-by-4.0Jun 2020View details →

Data used in the publication "The emission of terrestrial gamma-ray flashes associated to streamer coronae of the final leader step"

Simulation data used to create Fig. 2 of "The emission of terrestrial gamma-ray flashes associated to streamer coronae of the final leader step"

opencc-zeroJul 2020View details →

Data from: A global estimate of terrestrial net secondary production of primary consumers

Aim: Net Secondary production (NSP) emerges from the consumption of Net Primary Production (NPP) by any heterotrophic organism. There has been sporadic interest in the importance of NSP, but no global estimates have been produced. We revisit NSP and attempt a global estimate using contemporary NPP data combined with modern metabolic scaling theory for consumption rates. We distinguish between potential NSP as the amount of secondary production that could be supported by NPP, and realized NSP as the amount remaining after anthropogenic habitat disruption. Location: Global Time period: 2000-2014 Methods: We present a model of NSP implementing a Type II functional response for consumption rates wherein search efficiency and handling time are calculated based on consumer mass and ambient temperature. We solve this model for each 0.05-decimal-degree pixel in the global terrestrial biosphere using as data inputs NPP (MOD17A3) and land-surface temperature (MOD11C3). We aggregate estimates within global land cover classifications (MCD12C1) to obtain cover-specific and global estimates of NSP. We also correct our estimates based on declines in consumer abundance reported in Living Planet Report 2014. Results: We estimate potential NSP is 4.74 PgCy-1 globally (95%~CI~=~3.75--5.75). When we correct for global consumer population declines, realized NSP declines to 2.37 PgCy-1 (95%~CI~=~1.86--2.89), a loss of 50% in the rate of carbon flux through secondary consumers. Main Conclusions: Our estimates are sufficient to suggest that the flux of carbon through consumers is of a similar magnitude to many other fluxes critical to the global carbon cycle. We view this as a hypothesis to be tested that suggests NSP deserves significantly more attention in earth systems, macroecology, and biogeochemical research.

opencc-zeroAug 2020View details →

Data from: Evidence for the evolution of thermal tolerance but not desiccation tolerance in response to hotter, drier city conditions in a cosmopolitan, terrestrial isopod

Cities are often hotter and drier compared with nearby undeveloped areas, but how organisms respond to these multifarious stressors associated with urban heat islands is largely unknown. Terrestrial isopods are especially susceptible to temperature and aridity stress as they have retained highly permeable gills from their aquatic ancestors. We performed a two‐temperature common garden experiment with urban and rural populations of the terrestrial isopod, Oniscus asellus , to uncover evidence for plastic and evolutionary responses to urban heat islands. We focused on physiological tolerance traits including tolerance of heat, cold and desiccation. We also examined body size responses to urban heat islands, as size can modulate physiological tolerances. We found that different mechanisms underlie responses to urban heat islands. While evidence suggests urban isopods may have evolved higher heat tolerance, urban and rural isopods had statistically indistinguishable cold and desiccation tolerances. In both populations, plasticity to warmer rearing temperature diminished cold tolerance. Although field‐collected urban and rural isopods were the same size, rearing temperature positively affected body size. Finally, larger size improved desiccation tolerance, which itself was influenced by rearing temperature. Our study demonstrates how multifarious changes associated with urban heat islands, i.e. heat and aridity, will not necessarily contribute to contemporary evolution in each of the corresponding physiological traits.

opennotspecifiedJun 2020View details →

FIGURE 4 in Quantifying vertebrate zoogeographical regions of Australia using geospatial turnover in the species composition of mammals, birds, reptiles and terrestrial amphibians

FIGURE 4. The zoogeographical regions proposed by Cracraft (1991, thick black lines) and superimposed over the three clusters found in this study.

opencc-zeroAug 2020View details →

Change in terrestrial human footprint drives continued loss of intact ecosystems

Human pressure mapping is important for understanding humanity's role in shaping Earth's patterns and processes. Our ability to map this influence has evolved, thanks to powerful computing, earth observing satellites, and new bottom-up census and crowd-sourced data. Here, we provide the latest temporally inter-comparable maps of the terrestrial human footprint, and assessment of change in human pressure at global, biome, and ecoregional scales. In 2013, 42% of terrestrial Earth could be considered relatively free of direct anthropogenic disturbance, and 25% could be classed as 'wilderness' (the least degraded end of the human footprint spectrum). Between 2000 and 2013, 1.9 million km2 of land relatively free of human disturbance became highly modified. The majority of this occurred within tropical and subtropical grasslands, savannah, and shrubland ecosystems, but the rainforests of Southeast Asia also underwent rapid modification. Our results show that humanity's footprint is eroding Earth's last intact ecosystems, and greater efforts are urgently needed to retain them.

opencc-zeroAug 2020View details →

Data from: Tandem host-parasite dispersal inferred from similarities in phylogeographic patterns among little penguins and their 'terrestrial' ectoparasites

Aim Organisms with poor intrinsic dispersal capacity, such as parasites, often rely entirely on transport with host species that have a greater dispersal capacity. Penguins, for example, are exploited by terrestrial ectoparasites when they come ashore to breed. Recent research indicates that little penguin (Eudyptula minor and E. novaehollandiae) hard ticks (Ixodes eudyptidis and I. kohlsi) may be capable of surviving short periods (days) at sea with their hosts, but their capacity to survive longer voyages (weeks) is not known. We here aimed to assess whether phylogeographic patterns in little penguins and their ticks indicate that the terrestrial ectoparasites are able to disperse long distances at sea with their swimming hosts. Location Southern Australia and New Zealand. Taxon Ixodes eudyptidis and I. kohlsi ticks. Methods We conducted a broad-scale genomic assessment of little penguin ticks from across their hosts' ranges in Australia and New Zealand. Using Genotyping by Sequencing (GBS), we generated SNP data sets from ticks from 14 penguin colonies, and analysed phylogeographic structure. We included ticks from some sympatric flighted seabirds to verify host-specificity. Results We resolved two distinct lineages of Ixodes from little penguins, with one restricted to Australia, and the other found throughout New Zealand and in low numbers at some eastern Australian sites. Both lineages exhibited phylogeographic structure consistent with patterns observed in their hosts, with some evidence of occasional oceanic dispersal, including across the Tasman Sea between Australia and New Zealand. Ticks from sympatric short-tailed shearwaters (Ardenna tenuirostris), which disperse aerially, were genetically distinct from those collected from little penguins, supporting prior evidence of host-specificity in seabird ticks. Main conclusions The most parsimonious explanation for our results is that ticks can travel at sea with little penguins. We infer that some terrestrial ectoparasites associated with aquatically-dispersing hosts have evolved the capacity to survive oceanic voyages.

opencc-by-4.0Aug 2020View details →

Data from: Monitoring and predictive mapping of floristic biodiversity along a climatic gradient in ENSO's terrestrial core region, NW Peru

This is the data from the publication "Monitoring and predictive mapping of floristic biodiversity along a climatic gradient in ENSO's terrestrial core region, NW Peru" (<a href="http://onlinelibrary.wiley.com/doi/10.1111/ecog.05091/abstract">http://onlinelibrary.wiley.com/doi/10.1111/ecog.05091/abstract</a>). The code (including figures, appendices and the manuscript) can be found directly in the <a href="https://github.com/jannes-m/2020-enso-tdf">GitHub repository</a>. Data sources and description Column descriptions for all tables can be found in variable_description.ods. Following tables are stored in tables.gpkg: <ol> <li>plot_species_matrix_2011: Plot species matrix recorded in 2011</li> <li>plot_species_matrix_2012: Plot species matrix recorded in 2012.</li> <li>plot_species_matrix_2016: Plot species matrix recorded in 2016.</li> <li>plot_species_matrix_2017: Plot species matrix recorded in 2017.</li> <li>lifeform: Lifeforms of the recorded species</li> <li>plot_variables: Variables specific to the plots such as height of the first tree layer, cover of dead wood, etc.</li> <li>soil: Edaphic variables.</li> <li>topography: Topographic variables.</li> <li>streets: Streets and dirt tracks in the study area.</li> <li>towns: Polygons displaying the outline of the cities Paita, Piura and Chulucanas.</li> <li>rivers: Lines displaying the major rivers in the study area.</li> <li>study_area: Outline of the study area.</li> <li>peru: Outline of Peru.</li> <li>neighbors: Outline of Peru's neighbors (Bolivia, Brazil, Chile, Colombia, Ecuador).</li> <li>coast: Coastal strip of and close to the study area.</li> <li>precipitation: Precipitation measured at the three climatic stations (Paita, Piura, Chulucanas).</li> <li>experiment_count: species counted per visit (irrigation-fertilization experiment).</li> <li>experiment_irrigation: Rain input by time during the irrigation-fertilization experiment.</li> <li>experiment_cover: Cover of each plant species per visit and per experimental plot (irrigation-fertilization experiment).</li> </ol>

Relationships of mass properties and body proportions to locomotor habit in terrestrial Archosauria

Throughout their 250 Myr history, archosaurian reptiles have exhibited a wide array of body sizes, shapes and locomotor habits, especially in regard to terrestriality. These features make Archosauria a useful clade with which to study the interplay between body size, shape and locomotor behaviour, and how this interplay may have influenced locomotor evolution. Here, digital volumetric models of 80 taxa are used to explore how mass properties and body proportions relate to each other and locomotor posture in archosaurs. One-way, non-parametric, multivariate analysis of variance, based on the results of principal components analysis, shows that bipedal and quadrupedal archosaurs are largely distinguished from each other on the basis of just four anatomical parameters (P < 0.001): mass, centre of mass position and relative forelimb and hindlimb lengths. This facilitates the development of a quantitative predictive framework that can help assess gross locomotor posture in understudied or controversial taxa, such as the crocodile-line Batrachotomus (predicted quadruped) and Postosuchus (predicted biped). Compared to quadrupedal archosaurs, bipedal species tend to have relatively longer hindlimbs and a more caudally positioned whole-body centre of mass, and collectively exhibit greater variance in forelimb lengths. These patterns are interpreted to reflect differing biomechanical constraints acting on the archosaurian bauplan in bipedal versus quadrupedal groups, which may have shaped the evolutionary histories of their respective members.

Data from: The impact of anthropogenic disturbances on the genetic diversity of terrestrial species: a global meta-analysis

Duplicate of 10.5061/dryad.6hdr7sqxq Human activities are primarily responsible for habitat loss and changes in natural environments around the world. It has been suggested that populations inhabiting human-modified landscapes experience reduced gene flow, inbreeding depression, and loss of alleles due to genetic drift. However, the empirical evidence shows contrasting effects of anthropogenic disturbances on the genetic diversity of species. We performed a meta-analysis of 61 studies that compared the genetic diversity of plant and/or animal populations in disturbed and more preserved areas (316 paired comparisons) to investigate the genetic responses to different disturbance types. There is a negative effect (effect size: -0.45; 95% CI: -0.61, -0.29) of disturbances on genetic diversity, in which the most detrimental effects are caused by the loss of connectivity and forest cover. The methodological approach can explain part of the heterogeneity among the genetic responses detected by primary studies: (i) studies using the number of effective alleles did not detect genetic erosion, while all other indices, revealed negative responses to disturbances; and (ii) only studies performed with transferred or a combination of transferred and specific microsatellites detected negative responses. The effects on animal populations are more detrimental than in plant populations. Only plant species with shrub life form, self-incompatible reproductive systems, and biotic pollination and seed dispersal, showed negative responses to disturbances. Despite all heterogeneity among studies, there is an overall negative effect of disturbances on the genetic diversity, which indicates that remaining populations inhabiting human-modified landscapes have reduced evolutionary potential and are prone to local extinction.

Data from: Similarity in mycorrhizal communities associating with two widespread terrestrial orchids decays with distance

Aim: Interactions with mycorrhizal fungi are increasingly recognized as an important factor underlying the distribution and abundance of orchid species. However, the geographic distribution of orchid mycorrhizal fungi (OMF) and how their communities vary over large geographical areas are less well understood. Because climatic and environmental similarity may decrease with geographical distance or because some OMF have limited dispersal capabilities, similarities in orchid mycorrhizal communities can be expected to decrease with increasing distances separating orchid populations. However, up till now empirical evidence is largely lacking. Location: Eurasia Taxa: Gymnadenia conopsea (L.) R. Brown and Epipactis helleborine (L.) Crantz Methods: High-throughput sequencing was used to perform a cross-continental comparison of OMF that associate with two widespread Eurasian terrestrial orchids, Epipactis helleborine and Gymnadenia conopsea. Both phylogenetic and non-phylogenetic measures of community dissimilarity and their components were calculated and related to geographic distances using Mantel tests. Results: Our results showed that in both orchid species similarity in mycorrhizal communities decreased significantly with geographical distance. Decomposing the contribution of spatial turnover and nestedness to overall dissimilarity showed that the observed dissimilarity was mainly the result of species replacement between regions, and not of species loss. Similarly, a strong relationship was observed between phylogenetic community dissimilarity and geographic distance. Decomposing PCD values into a nonphylogenetic and phylogenetic component showed that orchid populations located closely next to each other were likely to contain the same OTUs, but that the non-shared taxa came from different phylogenetic clades. Species indicator analyses showed that the majority of OMF OTUs were restricted to particular geographic areas. However, some OTUs occurred in both continents, indicating that some fungi have very wide distributions. Main conclusions: Overall, these results demonstrate that orchid mycorrhizal communities differ substantially across large geographic areas, but that the distribution of orchids is not necessarily restricted by the distribution of particular OMF. Hence, widespread orchid species can be considered mycorrhizal generalists that are flexible in the OMF with which they associate across large geographic areas.

Data from: Terrestrial contributions to Afrotropical aquatic food webs: the Congo River case

1. Understanding the degree to which aquatic and terrestrial primary production fuel tropical aquatic food webs remains poorly understood, and quantifying the relative contributions of autochthonous and allochthonous inputs is methodologically challenging. Carbon and nitrogen stable isotope ratios (δ13C, δ15N) can provide valuable insights about contributions of terrestrial resources and trophic position respectively, but this approach has caveats when applied in typical complex natural food webs. 2. Here, we used a combination of C, N, and H (δ2H) stable isotope measurements and Bayesian mixing models to estimate the contribution of terrestrial (allochthonous) and aquatic (autochthonous) inputs to fish and invertebrate communities in the Congo River (and some tributaries). 3. Overall, our results show that we gained power to distinguish sources by using a multiple tracer approach and we were able to discriminate aquatic vs. terrestrial sources (esp. including hydrogen isotopes). Fish δ2H values were clearly correlated with their food preferences and revealed a high level of variation in the degree of allochthony in these tropical aquatic communities. 4. At the community level, it is clear that terrestrial C3 plants are an important source fueling the Congo River food web. However, in order to better constrain source contribution in these complex environments will require more robust constraints on stable isotope values of algal and methane-derived C sources.

opencc-by-nc-sa-4.0Nov 2020View details →

Two videos showing mating behaviour of the terrestrial slug Deroceras cecconii (Gastropoda: Agriolimacidae)

The dataset consists of two videos showing the mating behaviour of Deroceras cecconii. Details are explained further in: Hutchinson, J.M.C, Reise, H. & Schlitt, B. (2020) Mating behaviour and genital anatomy of Deroceras cecconii (Pollonera, 1896), a widespread but overlooked slug from Italy, now introduced to eastern Germany. Archiv für Molluskenkunde 149: 221–236.    The video cecconii_mating.mp4 shows the mating from soon (<8 min) after the sarcobela have everted (defining the start of the courtship phase) until the separation after copulation, 93 min later. Behaviour has been speeded up by a factor of 10. These two slugs (p23912 and p23915 in the collection of the Senckenberg Museum of Natural History Görlitz) were collected from site G45 (43.7338°N 011.55662°E, province of Firenze, Italy) on 22.iii.2013 and the mating occurred on 5.iv.2013. To give a rough idea of scale, each slug was about 3 cm long.    The video cecconii_copulation.mp4 shows the entire copulation phase (when the penes evert fully and sperm is exchanged between them) of a different pair of slugs (p23903 and p23904 in the collection of the Senckenberg Museum of Natural History Görlitz). They were collected from site G43 (42.7771°N 011.1938°E, province of Grosseto, Italy) on 21.iii.2013 and the mating occurred on 17.iv.2013. The video plays at the true speed. In this mating, the copulation started 76-84 min after the start of courtship. Stills from this video make up Fig. 7A-L in the above article. To give a rough idea of scale, each slug was about 3 cm long.    Video recording used Samsung SHC-737P cameras with Fujinon YV10×5B-2 lenses connected to an ISIS-1624 digital video card. Video processing utilised Avisynth, VirtualDub2, and ffmpeg.    A video recording of another copulation of D. cecconii, in side view, is available at https://malagr.de/hutch/video/cecconii.htm.

opencc-zeroNov 2020View details →

The preservation potential of terrestrial biogeographic patterns

Extinction events in the geological past are similar to the present-day biodiversity crisis in that they have a pronounced biogeography, producing dramatic changes in the spatial distributions of species. Reconstructing paleobiogeographic patterns from fossils therefore allows us to examine the long-term processes governing the formation of regional biotas, and potentially helps build spatially-explicit models for future biodiversity loss in a potential '6th mass extinction' event. However, the extent to which biogeographic patterns can be preserved in the fossil record is not well understood. Here, we perform a suite of simulations based on the present-day distribution of North American mammals, aimed at quantifying the preservation potential of beta diversity and spatial richness patterns over extinction events of varying intensities, and after applying a stepped series of taphonomic filters. We show that taphonomic biases related to body size are the biggest barrier to reconstructing biogeographic patterns over extinction events, but that these may be compensated for by both the small-mammal record preserved in bird castings, as well as range-expansion in surviving species. Overall our results suggest that the preservation potential of biogeographic patterns is surprisingly high, and thus that the fossil record represents an invaluable dataset recording the changing spatial distribution of biota over key intervals in Earth History.

FIGURE 6. Baeticoniscus bullonorum n. gen., n in A new genus and species of cave-dwelling terrestrial isopod (Crustacea: Oniscidea Trichoniscidae) from Southern Spain

FIGURE 6. Baeticoniscus bullonorum n. gen., n. sp. Female paratype. A, dorsal view; B, cephalon, dorsal; C, pereonites 5–7, pleon and pleotelson, dorsal; D, detail of the honeycomb structure of the seventh pereonite.

FIGURE 2. Baeticoniscus bullonorum n. gen., n in A new genus and species of cave-dwelling terrestrial isopod (Crustacea: Oniscidea Trichoniscidae) from Southern Spain

FIGURE 2. Baeticoniscus bullonorum n. gen., n. sp. Male paratype. A, habitus, dorsal view; B, pereonites 1–6, transversal view (from the front), and pereonite 7, dorsal; C, head (cephalothorax), frontal; D, first antenna; E, second antenna; F, second antenna flagellum (apical cone omitted).

FIGURE 1 in A new genus and species of cave-dwelling terrestrial isopod (Crustacea: Oniscidea Trichoniscidae) from Southern Spain

FIGURE 1. Cueva de la Pileta of Benaoján, Málaga, Spain. A, entrance to the cave; B, view of one of the halls inside (photos provided by Bullón family and Juan Mayoral).

FIGURE 4. Baeticoniscus bullonorum n. gen., n in A new genus and species of cave-dwelling terrestrial isopod (Crustacea: Oniscidea Trichoniscidae) from Southern Spain

FIGURE 4. Baeticoniscus bullonorum n. gen., n. sp. Male paratype. A, first pereopod; B, detail of propodus and dactylus of first pereopod; C, first male pleopod; D, second male pleopod; E, genital papilla.

FIGURE 5. Baeticoniscus bullonorum n. gen., n in A new genus and species of cave-dwelling terrestrial isopod (Crustacea: Oniscidea Trichoniscidae) from Southern Spain

FIGURE 5. Baeticoniscus bullonorum n. gen., n. sp. Male paratype. A, seventh pereopod; B, detail of propodus and dactylus of seventh pereopod.

FIGURE 3. Baeticoniscus bullonorum n. gen., n in A new genus and species of cave-dwelling terrestrial isopod (Crustacea: Oniscidea Trichoniscidae) from Southern Spain

FIGURE 3. Baeticoniscus bullonorum n. gen., n. sp. Male paratype. A, first maxilla outer and inner endites; B, maxilliped, distal portion; C, second maxilla distal portion, frontal and ventral; D, right mandible; E, left mandible.