bluuebunny/crossref_metadata_2025_split huggingface dataset:
Extinction of biotic interactions due to habitat loss could accelerate the current biodiversity crisis
Authors: Sandor Manette E. , Elphick Chris S. , Tingley Morgan W. 
Published: April 2022

AbstractHabitat loss disrupts species interactions through local extinctions, potentially orphaning species that depend on interacting partners, via mutualisms or commensalisms, and increasing secondary extinction risk. Orphaned species may become functionally or secondarily extinct, increasing the severity of the current biodiversity crisis. While habitat destruction is a major cause of biodiversity loss, the number of secondary extinctions is largely unknown. We investigate the relationship between habitat loss, orphaned species, and bipartite network properties. Using a real seed dispersal network, we simulate habitat loss to estimate the rate at which species are orphaned. To be able to draw general conclusions, we also simulate habitat loss in synthetic networks to quantify how changes in network properties affect orphan rates across broader parameter space. Both real and synthetic network simulations show that even small amounts of habitat loss can cause up to 10% of species to be orphaned. More area loss, less connected networks, and a greater disparity in the species richness of the network's trophic levels generally result in more orphaned species. As habitat is lost to land‐use conversion and climate change, more orphaned species increase the loss of community‐level and ecosystem functions. However, the potential severity of repercussions ranges from minimal (no species orphaned) to catastrophic (up to 60% of species within a network orphaned). Severity of repercussions also depends on how much the interaction richness and intactness of the community affects the degree of redundancy within networks. Orphaned species could add substantially to the loss of ecosystem function and secondary extinction worldwide.
Informing conservation decisions to target private lands of highest ecological value and risk of loss
Authors: Hansen Andrew J. , Mullan Katrina , Theobald David M. , Robinson Nathaniel , East Alyson , Powell Scott 
Published: April 2022

AbstractNatural habitats on private lands are potentially important components of national biodiversity conservation strategies, yet they are being rapidly lost to development. Conservation easements and other means of protecting these habitats have expanded in use and will be most effective if they target private lands of highest biodiversity value and risk of loss. We developed a Biodiversity Conservation Priority Index (BCPI) based on ecological value and risk of habitat loss for remaining areas of natural vegetation cover (NVC) in the northwestern United States and addressed two questions: (1) Which remaining NVC on private lands is the highest priority for biodiversity conservation based on ecological value and risk of development? And (2) are conservation easements in NVC placed preferentially in locations of high biodiversity conservation priority? Drawing on the concept of ecological integrity, we integrated five metrics of ecological structure, function, and composition to quantify ecological value of NVC. These included net primary productivity, species richness, ecosystem type representation, imperiled species range rarity, and connectivity among “Greater Wildland Ecosystems.” Risk of habitat loss was derived from analysis of biophysical and sociodemographic predictors of NVC loss. Ecological value and risk of loss were combined into the BCPI. We then analyzed spatial patterns of BCPI to identify the NVC highest in biodiversity conservation priority and examined the relationship between BCPI and conservation easement status. We found that BCPI varied spatially across the study area and was highest in western and southern portions of the study area. High BCPI was associated with suburban and rural development, roads, urban proximity, valley bottom landforms, and low intensity of current development. Existing conservation easements were distributed more towards lower BCPI values than unprotected NVC at both the study area and region scales. The BCPI can be used to better inform land use decision making at local, regional, and potentially national scales in order to better achieve biodiversity goals.
Age structure affects population productivity in an exploited fish species
Authors: Ohlberger Jan , Langangen Øystein , Stige Leif Chr. 
Published: April 2022

AbstractLong‐term changes in the age and size structure of animal populations are well documented, yet their impacts on population productivity are poorly understood. Fishery exploitation can be a major driver of changes in population age–size structure because fisheries significantly increase mortality and often selectively remove larger and older fish. Climate change is another potential driver of shifts in the demographic structure of fish populations. Northeast Arctic (NEA) cod is the largest population of Atlantic cod (Gadus morhua) and one of the world's most important commercial fish stocks. This population has experienced considerable changes in population age–size structure over the past century, largely in response to fishing. In this study, we investigate whether changes in spawner age structure have affected population productivity in NEA cod, measured as recruits per spawning stock biomass, over the past 75 years. We find evidence that shifts in age structure toward younger spawners negatively affect population productivity, implying higher recruitment success when the spawning stock is composed of older individuals. The positive effect of an older spawning stock is likely linked to maternal effects and higher reproductive output of larger females. Our results indicate a threefold difference in productivity between the youngest and oldest spawning stock that has been observed since the 1950s. Further, our results suggest a positive effect of environmental temperature and a negative effect of intraspecific cannibalism by older juveniles on population productivity, which partly masked the effect of spawner age structure unless accounted for in the model. Collectively, these findings emphasize the importance of population age structure for the productivity of fish populations and suggest that harvest‐induced demographic changes can have negative feedbacks for fisheries that lead to a younger spawning stock. Incorporating demographic data into harvest strategies could thus facilitate sustainable fishery management.
Plastid genomes reveal evolutionary shifts in elevational range and flowering time of Osmanthus (Oleaceae)
Authors: Li Yongfu , Li Xuan , Sylvester Steven Paul , Zhang Min , Wang Xianrong , Duan Yifan 
Published: April 2022

AbstractSpecies of Osmanthus are economically important ornamental trees, yet information regarding their plastid genomes (plastomes) have rarely been reported, thus hindering taxonomic and evolutionary studies of this small but enigmatic genus. Here, we performed comparative genomics and evolutionary analyses on plastomes of 16 of the 28 currently accepted species, with 11 plastomes newly sequenced. Phylogenetic studies identified four main lineages within the genus that are here designated the: “Caucasian Osmanthus” (corresponding to O. decorus), “Siphosmanthus” (corresponding to O. sect. Siphosmanthus), “O. serrulatus + O. yunnanensis,” and “Core Osmanthus: (corresponding to O. sect. Osmanthus + O. sect. Linocieroides). Molecular clock analysis suggested that Osmanthus split from its sister clade c. 15.83 Ma. The estimated crown ages of the lineages were the following: genus Osmanthus at 12.66 Ma; “Siphosmanthus” clade at 5.85 Ma; “O. serrulatus + O. yunnanensis” at 4.89 Ma; and “Core Osmanthus: clade at 6.2 Ma. Ancestral state reconstructions and trait mapping showed that ancestors of Osmanthus were spring flowering and originated at lower elevations. Phylogenetic principal component analysis clearly distinguished spring‐flowering species from autumn‐flowering species, suggesting that flowering time differentiation is related to the difference in ecological niches. Nucleotide substitution rates of 80 common genes showed slow evolutionary pace and low nucleotide variations, all genes being subjected to purifying selection.
Application of GPS occurrence data to understand African white‐backed vulturesGyps africanusspatial home range overlaps
Authors: Zvidzai Mark , Zengeya Fadzai Michelle , Masocha Mhosisi , Ndaimani Henry , Murwira Amon 
Published: April 2022

AbstractUnderstanding key overlap zones and habitats which are intensively shared by species in space and time is crucial as it provides vital information to inform spatial conservation with maximum benefits. The advent of high‐resolution GPS technologies associated with new analytical algorithms is revolutionizing studies underpinning species spatial and social interaction patterns within ecosystems. Here, using a robust home range estimation algorithm, the autocorrelated kernel density estimator (AKDE) equipped with an equally powerful home range overlap metric, the Bhattacharyya's coefficient (BC), we provide one of the first attempts to estimate and delineate spatial home range overlap zones for critically endangered African white‐backed vultures to inform conservation planning. Six vultures were captured in Hwange National Park using a modified cannon net system after which they were tagged and tracked with high‐resolution GPS backpacks. Overall, results suggested weaker average home range overlaps based on both the pooled data (0.38 ± 0.26), wet non‐breeding seasonal data (0.32 ± 0.23), and dry breeding season data (0.34 ± 0.28). Vultures 4, 5, and 6 consistently revealed higher home range overlaps across all the scales with values ranging between 0.60 and 0.99. Individual vultures showed consistence in space use patterns as suggested by high between‐season home range overlaps, an indication that they may be largely resident within the Hwange ecosystem. Importantly, we also demonstrate that home range overlapping geographic zones are all concentrated within the protected area of Hwange National Park. Our study provides some of the first results on African vulture home range overlaps and segregation patterns in the savanna ecosystem based on unbiased telemetry data and rigorous analytical algorithms. Such knowledge may provide vital insights for prioritizing conservation efforts of key geographic overlap zones to derive maximum conservation benefits especially when targeting wide‐ranging and critically endangered African white‐backed vultures. To this end, spatial overlap zones estimated here, although based on a small sample size, could provide a strong foundation upon which other downstream social and ecological questions can be explored further to expand our understanding on shared space use mechanisms among African vulture species.
Time series covering up to four decades reveals major changes and drivers of marine growth and proportion of repeat spawners in an Atlantic salmon population
Authors: Harvey Alison , Skaala Øystein , Borgstrøm Reidar , Fjeldheim Per Tommy , Christine Andersen Kaja , Rong Utne Kjell , Askeland Johnsen Ingrid , Fiske Peder , Winterthun Synne , Knutar Sofie , Sægrov Harald , Urdal Kurt , Alan Glover Kevin 
Published: April 2022

Abstract

Wild Atlantic salmon populations have declined in many regions and are affected by diverse natural and anthropogenic factors. To facilitate management guidelines, precise knowledge of mechanisms driving population changes in demographics and life history traits is needed.

Our analyses were conducted on (a) age and growth data from scales of salmon caught by angling in the river Etneelva, Norway, covering smolt year classes from 1980 to 2018, (b) extensive sampling of the whole spawning run in the fish trap from 2013 onwards, and (c) time series of sea surface temperature, zooplankton biomass, and salmon lice infestation intensity.

Marine growth during the first year at sea displayed a distinct stepwise decline across the four decades. Simultaneously, the population shifted from predominantly 1SW to 2SW salmon, and the proportion of repeat spawners increased from 3 to 7%. The latter observation is most evident in females and likely due to decreased marine exploitation. Female repeat spawners tended to be less catchable than males by anglers.

Depending on the time period analyzed, marine growth rate during the first year at sea was both positively and negatively associated with sea surface temperature. Zooplankton biomass was positively associated with growth, while salmon lice infestation intensity was negatively associated with growth.

Collectively, these results are likely to be linked with both changes in oceanic conditions and harvest regimes. Our conflicting results regarding the influence of sea surface temperature on marine growth are likely to be caused by long‐term increases in temperature, which may have triggered (or coincided with) ecosystem shifts creating generally poorer growth conditions over time, but within shorter datasets warmer years gave generally higher growth. We encourage management authorities to expand the use of permanently monitored reference rivers with complete trapping facilities, like the river Etneelva, generating valuable long‐term data for future analyses.
Maternal dopamine exposure provides offspring starvation resistance in Daphnia
Authors: Issa Semona , Chaabani Safa , Asimakopoulos Alexandros G. , Jaspers Veerle L. B. , Einum Sigurd 
Published: April 2022

AbstractThe neurotransmitter dopamine has been shown to play an important role in modulating behavioral, morphological, and life history responses to food abundance. However, costs of expressing high dopamine levels remain poorly studied and are essential for understanding the evolution of the dopamine system. Negative maternal effects on offspring size from enhanced maternal dopamine levels have previously been documented in Daphnia. Here, we tested whether this translates into fitness costs in terms of lower starvation resistance in offspring. We exposed Daphnia magna mothers to aqueous dopamine (2.3 or 0 mg/L for the control) at two food levels (ad libitum vs. 30% ad libitum) and recorded a range of maternal life history traits. The longevity of their offspring was then quantified in the absence of food. In both control and dopamine treatments, mothers that experienced restricted food ration had lower somatic growth rates and higher age at maturation. Maternal food restriction also resulted in production of larger offspring that had a superior starvation resistance compared to ad libitum groups. However, although dopamine exposed mothers produced smaller offspring than controls at restricted food ration, these smaller offspring survived longer under starvation. Hence, maternal dopamine exposure provided an improved offspring starvation resistance. We discuss the relative importance of proximate and ultimate causes for why D. magna may not evolve toward higher endogenous dopamine levels despite the fitness benefits this appears to have.
A nondestructive method of calculating the wing area of insects
Authors: Yu Kexin , Reddy Gadi V. P. , Schrader Julian , Guo Xuchen , Li Yirong , Jiao Yabing , Shi Peijian 
Published: April 2022

AbstractMost insects engage in winged flight. Wing loading, that is, the ratio of body mass to total wing area, has been demonstrated to reflect flight maneuverability. High maneuverability is an important survival trait, allowing insects to escape natural enemies and to compete for mates. In some ecological field experiments, there is a need to calculate the wing area of insects without killing them. However, fast, nondestructive estimation of wing area for insects is not available based on past work. The Montgomery equation (ME), which assumes a proportional relationship between leaf area and the product of leaf length and width, is frequently used to calculate leaf area of plants, in crops with entire linear, lanceolate leaves. Recently, the ME was proved to apply to leaves with more complex shapes from plants that do not have any needle leaves. Given that the wings of insects are similar in shape to broad leaves, we tested the validity of the ME approach in calculating the wing area of insects using three species of cicadas common in eastern China. We compared the actual area of the cicadas’ wings with the estimates provided by six potential models used for wing area calculation, and we found that the ME performed best, based on the trade‐off between model structure and goodness of fit. At the species level, the estimates for the proportionality coefficients of ME for three cicada species were 0.686, 0.693, and 0.715, respectively. There was a significant difference in the proportionality coefficients between any two species. Our method provides a simple and powerful approach for the nondestructive estimation of insect wing area, which is also valuable in quantifying wing morphological features of insects. The present study provides a nondestructive approach to estimating the wing area of insects, allowing them to be used in mark and recapture experiments.
Moose in our neighborhood: Does perceived hunting risk have cascading effects on tree performance in vicinity of roads and houses?
Authors: Mehlhoop Anne C. , Van Moorter Bram , Rolandsen Christer M. , Hagen Dagmar , Granhus Aksel , Eriksen Rune , Ringsby Thor Harald , Solberg Erling J. 
Published: April 2022

AbstractLike large carnivores, hunters both kill and scare ungulates, and thus might indirectly affect plant performance through trophic cascades. In this study, we hypothesized that intensive hunting and enduring fear of humans have caused moose and other forest ungulates to partly avoid areas near human infrastructure (perceived hunting risk), with positive cascading effects on recruitment of trees. Using data from the Norwegian forest inventory, we found decreasing browsing pressure and increasing tree recruitment in areas close to roads and houses, where ungulates are more likely to encounter humans. However, although browsing and recruitment were negatively related, reduced browsing was only responsible for a small proportion of the higher tree recruitment near human infrastructure. We suggest that the apparently weak cascading effect occurs because the recorded browsing pressure only partly reflects the long‐term browsing intensity close to humans. Accordingly, tree recruitment was also related to the density of small trees 5–10 years earlier, which was higher close to human infrastructure. Hence, if small tree density is a product of the browsing pressure in the past, the cascading effect is probably stronger than our estimates suggest. Reduced browsing near roads and houses is most in line with risk avoidance driven by fear of humans (behaviorally mediated), and not because of excessive hunting and local reduction in ungulate density (density mediated).
Mechanisms and drivers of alternative shrubland states
Authors: Archer Steven R. , Peters Debra P. C. , Burruss N. Dylan , Yao Jin 
Published: April 2022

AbstractGrassland‐to‐shrubland state change has been widespread in arid lands globally. Long‐term records at the Jornada Basin USDA‐LTER site in the North American Chihuahuan Desert document the time series of transition from grassland dominance in the 1850s to shrubland dominance in the 1990s. This broadscale change ostensibly resulted from livestock overgrazing in conjunction with periodic drought and represents the classic “grassland‐to‐shrubland” regime shift. However, finer‐scale observations reveal a more nuanced view of this state change that includes transitions from dominance by one shrub functional type to another (e.g., based on leaf habit [evergreen vs. deciduous], N2 fixation potential, and drought tolerance). We analyzed the Jornada Basin historic vegetation data using a fine‐scale grid and classified the dominant vegetation in the resulting 890 cells on each of four dates (1858, 1915, 1928, and 1998). This analysis allowed us to quantify on contrasting soil geomorphic units the rate and spatial distribution of: (1) state change from grasslands to shrublands across the Jornada Basin, (2) transitions between shrub functional groups, and (3) transitions from shrub‐to‐grass dominance. Results from our spatially explicit, decadal timescale perspective show that: (1) shrubland ecosystems developing on former grasslands were spatially and temporally more dynamic than has been generally presumed, (2) in some locations, shrublands initially developing on grasslands subsequently transitioned to ecosystems dominated by a different shrub functional type, with these changes in shrub composition likely involving changes in soil properties, and (3) some shrub‐dominated locations have reverted to grass dominance. Accordingly, traditional, broad characterizations of “grassland‐to‐shrubland” state change may be too simplistic. An accounting of these complexities and transitions from one shrub functional group to another is important for projecting state change consequences for ecosystem processes. Understanding the mechanisms, drivers, and influence of interactions between patterns and processes on transitions between shrub states defined by woody plant functional types will be germane to predicting future landscape change.
TrophicCS: Spatialized trophic data of the Celtic Sea continental shelf food web
Authors: Robert Marianne , Pawlowski Lionel , Kopp Dorothée 
Published: April 2022

AbstractUnderstanding the dynamics of species interactions for food (prey–predator, competition for resources) and the functioning of trophic networks (dependence on trophic pathways, food chain flows, etc.) has become a thriving ecological research field in recent decades. This empirical knowledge is then used to develop population and ecosystem modeling approaches to support ecosystem‐based management. The TrophicCS data set offers spatialized trophic information on a large spatial scale (the entire Celtic Sea continental shelf and upper slope) for a wide range of species. It combines ingested prey (gut content analysis) and a more integrated indicator of food sources (stable isotope analysis). A total of 1337 samples of large epifaunal invertebrates (bivalve mollusks and decapod crustaceans), zooplankton, fish, and cephalopods, corresponding to 111 taxa (94% determined at the species level), were collected and analyzed for stable isotope analysis of their carbon and nitrogen content. Samples were collected between 2014 and 2016, mostly during the month of November and between 57 and 516 m depth. Sample size varied between taxa (from 1 to 52), with 98 taxa having at least three samples. The gut contents of 1027 fish belonging to 10 commercially important species: black anglerfish (Lophius budegassa), white anglerfish (Lophius piscatorius), blue whiting (Micromesistius poutassou), cod (Gadus morhua), haddock (Melanogrammus aeglefinus), hake (Merluccius merluccius), megrim (Lepidorhombus whiffiagonis), plaice (Pleuronectes platessa), sole (Solea solea), and whiting (Merlangius merlangus) were analyzed. Sampling occurred in November 2014 and 2015. The gut content data set contains the occurrence of prey in gut, identified to the lowest taxonomic level possible. No prey were assigned for 274 empty gut contents. To consider potential ontogenetic diet changes, a large size range was sampled for each species. The TrophicCS data set was used to improve understanding of trophic relationships and ecosystem functioning in the Celtic Sea. Data are released under a CC‐BY‐NC‐SA license, and please cite this paper when reusing the data.