Intraspecific Relationships Research Articles

Ecological and Behavioral Drivers of Supplemental Feeding Use by Roe Deer Capreolus capreolus in a Peri-Urban Context.

Simple SummarySupplementary feeding of ungulates is widespread in many European countries. However, little is known on the actual patterns of use of feeding sites by animals, and the effects of this practice on inter-individual relationships. We monitored the use of feeding sites in a population of roe deer living in the Italian Alps using camera traps, to enable continuous monitoring of feeding sites and to detect co-occurring visits by multiple individuals. We found that roe deer visits to feeding sites decreased from winter to spring at the onset of vegetation regrowth and when the temperature increases. During the 24 h cycle, roe deer visited feeding sites mainly at crepuscular hours, both solitarily (the majority of the cases) and in groups, with no substantial differences between sexes. When roe deer gathered at feeding sites, they spent more time there, therefore, exhibiting a certain tolerance to the presence of conspecifics. The presence and use of feeding sites did not alter the daily activity cycle and opportunistic use of resources in roe deer, however, they conditioned the intra-specific interactions, with potential behavioral and epidemiological consequences.Winter supplemental feeding of ungulates potentially alters their use of resources and ecological interactions, yet relatively little is known about the patterns of feeding sites use by target populations. We used camera traps to continuously monitor winter and spring feeding site use in a roe deer population living in a peri-urban area in Northern Italy. We combined circular statistics with generalized additive and linear mixed models to analyze the diel and seasonal pattern of roe deer visits to feeding sites, and the behavioral drivers influencing visit duration. Roe deer visits peaked at dawn and dusk, and decreased from winter to spring when vegetation regrows and temperature increases. Roe deer mostly visited feeding sites solitarily; when this was not the case, they stayed longer at the site, especially when conspecifics were eating, but maintained a bimodal diel pattern of visits. These results support an opportunistic use of feeding sites, following seasonal cycles and the roe deer circadian clock. Yet, the attractiveness of these artificial resources has the potential to alter intra-specific relationships, as competition for their use induces gatherings and may extend the contact time between individuals, with potential behavioral and epidemiological consequences.

Evaluation of dark jute SSR markers and morphological traits in genetic diversity assessment of jute mallow (Corchorus olitorius L.) cultivars

The jute mallow (C. olitorius L.) is an important nutritious green leafy vegetable in the tropical region of Africa. This study assesses the extent of genetic diversity and intra-specific relationships among 16 cultivated jute mallows of Nigeria (14), [Ghana (1) and Togo (1), used as checks, evaluating 16 dark jute SSR markers and 16 morphological traits (quantitative and qualitative). The study reveals moderate to high variation among the cultivars in the number of pods, pod yield and plant height traits. Based on the principal component (PC) analysis of the quantitative traits, the pod length, pod width, number of pods, pod yield and plant height are important traits composing PC1. On the other hand, the pod pedicel length and days of 50% flowering traits are highly correlated variables in PC2. Pod length, pod width, pod pedicel length and plant height account for the total diversity. Two main groups (I and II) and an outgroup are identified among the 16 cultivars based on the quantitative traits. among the cultivars, leaf shapes identified are ovate (38% of cultivars), lanceolate (6%), oblanceolate (25%) and palmately lobed (31%). Three markers which have monomorphic alleles are excluded and thirteen markers are used to analyse the genetic diversity. A total of 41 alleles are amplified using the 13 polymorphic markers with an average of 2.75 per locus. The mean polymorphism information content (PIC) value is 0.42, ranging from 0.06 to 0.73. The mean gene diversity or expected heterozygosity = 0.05 (from 0.06 to 0.76). The observed heterozygosity (Ho) ranges from 0.00 to 0.88, with a mean of 0.60. The mean genetic dissimilarity is 0.35. Thus, the SSR data indicate a moderate genetic dissimilarity within jute mallow under study. Clustering using the neighbour-joining dendrogram predicated on the SSR data separates the cultivars into three major groups in which the two cultivars from Ghana and Togo show distinctiveness from the cultivars from Nigeria. Principal coordinate analysis of SSR data is consistent with neighbour-joining groupings. The study based on a set of dark jute markers and morphological traits reveals that the extent of genetic diversity of cultivated jute mallow and could be used in germplasm evaluation. In addition to the knowledge of the high genetic variability observed in the number of pod and the yield of some of the studied cultivars, further efforts are needed to characterise the cultivar pods’ nutritive values for human health.

Underwater video and still‐image dataset of fishes and other aquatic animals in Lake Biwa, Japan, observed via carp‐mounted video loggers

AbstractThis is the first large dataset of underwater videos from which species occurrence and behavioral records of aquatic organisms were identified in Lake Biwa, the largest lake in Japan. We compiled 109 videos and 122 still‐images of fishes, diving birds and shrimps. The images were cropped from videos taken underwater with animal‐borne video cameras which were mounted on the backs of common carp (Cyprinus carpio). The attribute of each image and its occurrence of organisms were formatted according to the Darwin Core Archive which was developed by the Biodiversity Information Standards (TDWG), and the dataset is available via the Global Biodiversity Information Facility. Our dataset includes records of 10 species, 4 genera, 2 families and 1 infraorder which includes mostly fishes, several birds and a crustacean. The fish records include a threatened endemic fish, the “gengorou‐buna” crucian carp (Carassius cuvieri), and two alien fishes, largemouth bass (Micropterus salmoides) and bluegill sunfish (Lepomis macrochirus). We confirmed several types of intraspecific and interspecific relationships between video‐mounted carp and other organisms; for example, most video‐mounted carp frequently approached or chased conspecifics upon encountering, which sometimes led to two carp feeding side by side. At least three avian species also appeared in the dataset: Eurasian coot (Fulica atra), little grebe (Tachybaptus ruficollis), great crested grebe (Podiceps cristatus), but there was no apparent interaction between carp and these birds. Our underwater videos reveal and highlight the rich biodiversity of the lake today, providing clear evidence for behavior of aquatic organisms under natural conditions.The complete data set for this abstract published in the Data Paper section of the journal is available in electronic format in MetaCat in JaLTER at http://db.cger.nies.go.jp/JaLTER/metacat/metacat/ERDP-2020-18.1/jalter-en.

Relationships between epiphyton and macrophytes (Characeae) in tropical reservoirs

ABSTRACT We analyzed structural attributes (epiphyton composition, richness, density, biomass, and life forms) involved in interactions between the epiphyton and Characeae (Chara and Nitella) in 19 tropical reservoir environments, 7 with the presence of Chara, 7 with Nitella, and 5 with both genera. A sampling station measuring 4 m² was defined in each environment for the collection of abiotic and biotic data without temporal repetition. Univariate and multivariate analyses were performed for the characterization of each environment. Regression analysis and partial redundancy analysis (pRDA) were used to test the substrate–epiphyton relationship. The substrate biomass was significantly associated (p < 0.05) with epiphyton biomass, total density, and filamentous forms. The pRDA revealed that epiphyton biomass was related to the 2 substrates, whereas composition was related to the environment (p < 0.05). A negative association was found between Chara and Spirogyra (36.2%). Nitella was positively associated with the genera Lyngbya, Oedocladium, and Oedonogium and negatively with Staurastrum, whose genera together accounted for 12.9% of the biomass of the community. Characeae (Chara and Nitella) did not exert a direct influence on total richness or composition; these attributes were explained by environmental factors. Chara and Nitella biomass had a positive interaction with epiphyton biomass and density, but each substrate promoted specificity and distinct intraspecific relationships in the epiphytic structure in the tropical reservoir environments.

Not so peaceful: aggressive encounters between Beni titi monkey (&lt;i&gt;Plecturocebus modestus&lt;/i&gt;) groups in Bolivia

We report observations of intergroup interactions from a free ranging group of the endemic and threatened Beni titi monkey (Plecturocebus modestus). Our observations over the course of one study year suggest that competition for food resources is the main reason for most observed intergroup encounters (n=64), including aggressive interactions (n=28). Additionally, threats to group integrity, such as potential loss of members, might promote very aggressive encounters, including three fights observed between adults of neighbouring groups. We provide new information on the intraspecific relationships for these endemic primates related to their use of space and food resources.

Selection for Divergent Reproductive Investment Affects Neuron Size and Foliation in the Cerebellum

The cerebellum has a highly conserved internal circuitry, but varies greatly in size and morphology within and across species. Despite this variation, the underlying volumetric changes among the layers of the cerebellar cortex or their association with Purkinje cell numbers and sizes is poorly understood. Here, we examine intraspecific scaling relationships and variation in the quantitative neuroanatomy of the cerebellum in Japanese quail (Coturnix japonica) selected for high or low reproductive investment. As predicted by the circuitry of the cerebellum, the volumes of the constituent layers of the cerebellar cortex were strongly and positively correlated with one another and with total cerebellar volume. The number of Purkinje cells also significantly and positively co-varied with total cerebellar volume and the molecular layer, but not the granule cell layer or white matter volumes. Purkinje cell size and cerebellar foliation did not significantly covary with any cerebellar measures, but differed significantly between the selection lines. Males and females from the high-investment lines had smaller Purkinje cells than males and females from the low-investment lines and males from the high-investment lines had less folded cerebella than quail from the low-investment lines. These results suggest that within species, the layers of the cerebellum increase in a coordinated fashion, but Purkinje cell size and cerebellar foliation do not increase proportionally with overall cerebellum size. In contrast, selection for differential reproductive investment affects Purkinje cell size and cerebellar foliation, but not other quantitative measures of cerebellar anatomy.

Partial Mitogenome Sequence of the Indian Crested Porcupine (Hystrix indica) in Turkey, with the Phylogeny of the Subgenus Hystrix

Mitogenomic data can provide valuable information that can be used to elucidate and reveal the evolutionary history and phylogenetic relationships. Recently, mitogenomes generated using high-throughput sequencing technologies have become more applicable in association with advanced analytical tools. In this study, to provide mitogenomic data for the Indian crested porcupine and to disclose the intraspecific and interspecific relationships within the subgenus Hystrix, partial mitogenome (7.525 bp) of one sample from Turkey that included coding and noncoding regions was initially sequenced using the Illumina MiSeq platform. The structure of the obtained partial mitogenome was similar to those of the other mammals. The partial mitogenome sequence of the Turkish sample was used for phylogenetic analyses together with published mitochondrial sequences of the species within the subgenus Hystrix registered in GenBank. Two mitochondrial regions (CytB and D-loop available in GenBank) were analyzed using the Bayesian, Maximum Likelihood, and Neighbor-Joining methods. Phylogenetic analyses revealed three major phylogroups (Hystrix cristata, H. indica, and H. africaeaustralis) within the subgenus Hystrix. This partial mitogenome sequence was the first data for the Turkish porcupine belonging to the species H. indica. As genetic data for H. indica are already limited, the present study would contribute to further phylogenetic studies that would be performed using mitogenomic data of the Indian crested porcupine and other porcupines.

Leaf traits and performance vary with plant age and water availability in Artemisia californica.

Leaf functional traits are strongly tied to growth strategies and ecological processes across species, but few efforts have linked intraspecific trait variation to performance across ontogenetic and environmental gradients. Plants are believed to shift towards more resource-conservative traits in stressful environments and as they age. However, uncertainty as to how intraspecific trait variation aligns with plant age and performance in the context of environmental variation may limit our ability to use traits to infer ecological processes at larger scales. We measured leaf physiological and morphological traits, canopy volume and flowering effort for Artemisia californica (California sagebrush), a dominant shrub species in the coastal sage scrub community, under conditions of 50, 100 and 150 % ambient precipitation for 3 years. Plant age was a stronger driver of variation in traits and performance than water availability. Older plants demonstrated trait values consistent with a more conservative resource-use strategy, and trait values were less sensitive to drought. Several trait correlations were consistent across years and treatments; for example, plants with high photosynthetic rates tended to have high stomatal conductance, leaf nitrogen concentration and light-use efficiency. However, the trade-off between leaf construction and leaf nitrogen evident in older plants was absent for first-year plants. While few traits correlated with plant growth and flowering effort, we observed a positive correlation between leaf mass per area and performance in some groups of older plants. Overall, our results suggest that trait sensitivity to the environment is most visible during earlier stages of development, after which intraspecific trait variation and relationships may stabilize. While plant age plays a major role in intraspecific trait variation and sensitivity (and thus trait-based inferences), the direct influence of environment on growth and fecundity is just as critical to predicting plant performance in a changing environment.

DNA Barcoding and Demographic History of Peromyscus yucatanicus (Rodentia: Cricetidae) Endemic to the Yucatan Peninsula, Mexico

The Yucatan Peninsula (YP) is a biotic province located in southeastern Mexico, delimited mainly by climatic variables. One endemic species of the YP is the Yucatan deer mouse Peromyscus yucatanicus. It is considered a member of the P. mexicanus species group, but some morphological characters and habitat preferences separate it from them. Herein, the DNA barcoding identification of P. yucatanicus, intraspecific relationships, and the level of genetic differentiation among its geographical distribution were examined. Sequences of the mitochondrial cytochrome c oxidase subunit 1 gene were used for the phylogenetic, demographic history, and genetic structure analysis. In addition, an ecological niche model was built and transferred to 6000 years ago in order to explore the current and past environmental suitability of the species. Results showed that P. yucatanicus was monophyletic and its phylogenetic relationships unresolved. Intraspecific analyses showed signatures of a scenario of demographic stability followed by population growth, and three genetic haplogroups were identified. Paleontological, paleoclimate, and the results presented here are useful to hypothesize that P. yucatanicus likely diverged in the Pleistocene and invaded the south of YP after the Last Glacial Period with the arrival of the current vegetation in the late Pleistocene—early-middle Holocene, and its demographic population was stable during the remaining Holocene epoch with slight growth at the late-middle Holocene resulting in the major precipitation changes that provided more plant coverage.

Development of high-resolution chloroplast markers for intraspecific phylogeographic studies of Phaeocystis globosa

Phaeocystis globosa is an important harmful algal bloom causative species distributing widely in temperate and tropical coastal waters in the world. The morphological, physiological, and biochemical characteristics are different among geographic strains, which can not be distinguished with nuclear ribosomal DNA markers at present. Therefore, the genetic distance and phylogeographic relationships of nuclear 28S rDNA D1-D2 and ITS regions, and three chloroplast intergenic spacers (petN-trnS1, trnM1-psbA, and rbcS-rpl27) were analyzed and compared among 13 strains of P. globosa isolated from the Pacific Ocean and Atlantic Ocean in this study. In addition, the nucleotide polymorphisms of 28S rDNA D1-D2, ITS, and rbcS-rpl27 regions were evaluated in two P. globosa strains. The various levels of nucleotide polymorphism were in the nuclear 28S rDNA D1-D2 region and ITS region, but no polymorphism was in the chloroplast rbcS-rpl27 intergenic spacer. A reasonable intraspecific phylogeographic relationship was presented by rbcS-rpl27 intergenic spacer, which had the strongest distinction to geographic strains compared to those of 28S rDNA D1-D2 and ITS regions. In the phylogenetic tree of rbcS-rpl27 intergenic spacer, the two strains from the North Sea of the Atlantic Ocean were divided firstly from the species of P. globosa, and then formed an independent clade, while the other Atlantic strains and all of Pacific strains joined up to build the other clade. It was implied that at least two genetically distant populations of P. globosa existed in the Atlantic coastal regions. This study provided a high-resolution chloroplast marker to analyze intraspecific phylogeographic populations of P. globosa, and preliminarily clarified the genetic relationships of the Pacific and Atlantic strains of P. globosa.

Taxonomy and phylogenetic relationship of zokors

Zokor (Myospalacinae) is one of the subterranean rodents, endemic to east Asia. Due to the convergent and parallel evolution induced by its special lifestyles, the controversies in morphological classification of zokor appeared at the level of family and genus. To resolve these controversies about taxonomy and phylogeny, the phylogenetic relationships of 20 species of Muroidea and six species of zokors were studied based on complete mitochondrial genome and mitochondrial Cytb gene, respectively. Phylogeny analysis of 20 species of Muroidea indicated that the zokor belonged to the family Spalacidae, and it was closer to mole rat rather than bamboo rat. Besides, by investigating the phylogenetic relationships of six species of zokors, the status of two genera of Eospalax and Myospalax was affirmed because the two clades differentiated in phylogenetic tree represented two types of zokors, convex occiput type and flat occiput type, respectively. In addition, the two origins in Eospalax were found diverged at 3.71 million years ago (Ma) based on estimation of divergence time. It is suggested that the climate and ecology changes caused by the Qinghai-Tibet Plateau uplift event in 3.6 Ma led to the inner divergence of Eospalax. The intraspecific phylogenetic relationships of partial zokors were well resolved, the two clades of Eospalax cansus represented two geographical populations, respectively, and the divergent pattern of Eospalax baileyi was characterized by allopatric divergence spatially. In this study, we explored the taxonomic status and phylogenetic relationships of Myospalacinae at the molecular level. These works would be significant to understanding the evolutionary process and to clarify the mechanism of differentiation of Myospalacinae.

Trophic position scales positively with body size within but not among four species of rocky reef predators

Intra- and interspecifically, larger-bodied predators generally occupy higher trophic positions (TPs). With widespread declines in large predators, there is a need to understand their size-based trophic roles to predict ecosystem-level responses. In British Columbia, Canada, we examined size-based trophic interactions between predatory fishes—3 rockfish species (genus Sebastes) and lingcod Ophiodon elongatus—and their prey, converting predator δ15N signatures to TP and analyzing stomach contents. Intraspecifically, TP scaled positively with predator length and gape width, but the rates of change varied by species. Interspecifically, TP did not scale positively with the observed mean sizes or known maximum sizes of species. Lingcod TP was lower than that of yelloweye and quillback rockfishes, which were 51 and 37%, respectively, smaller than lingcod. Yellowtail rockfish had the smallest average size, yet their mean TP did not differ significantly from that of lingcod. Neither species differences in some morphometric traits known to influence body size-TP relationships nor phylogenetic history explained these results. Most prey consumed were &lt;20% of the predator’s size, which might partially explain the lack of a size-based trophic hierarchy among species. Currently, large size classes of rockfishes are being lost due to fisheries and perhaps climate-driven changes. Our findings on intraspecific size-TP relationships indicate that fishery removals of large individuals may diminish trophic structures. Interspecific comparisons of TP suggest that, along with size, species remain an important factor in understanding trophic dynamics. In addition, smaller-bodied predator species may have significant ecological roles to be considered in ecosystem-based fisheries management.

A deeper meaning for shallow‐level phylogenomic studies: nested anchored hybrid enrichment offers great promise for resolving the tiger moth tree of life (Lepidoptera: Erebidae: Arctiinae)

AbstractAnchored hybrid enrichment (AHE) has emerged as a powerful tool for uncovering the evolutionary relationships within many taxonomic groups. AHE probe sets have been developed for a variety of insect groups, though none have yet been shown to be capable of simultaneously resolving deep and very shallow (e.g., intraspecific) divergences. In this study, we present NOC1, a new AHE probe set (730 loci) for Lepidoptera specialized for tiger moths and assess its ability to deliver phylogenetic utility at all taxonomic levels. We test the NOC1 probe set with 142 individuals from 116 species sampled from all the major lineages of Arctiinae (Erebidae), one of the most diverse groups of noctuoids (&gt;11 000 species) for which no well‐resolved, strongly supported phylogenetic hypothesis exists. Compared to previous methods, we generally recover much higher branch support (BS), resulting in the most well‐supported, well‐resolved phylogeny of Arctiinae to date. At the most shallow‐levels, NOC1 confidently resolves species‐level and intraspecific relationships and potentially uncovers cryptic species diversity within the genus Hypoprepia. We also implement a ‘sensitivity analysis’ to explore different loci combinations and site sampling strategies to determine whether a reduced probe set can yield results similar to those of the full probe set. At both deep and shallow levels, only 50–175 of the 730 loci included in the complete NOC1 probe set were necessary to resolve most relationships with high confidence, though only when the more rapidly evolving sites within each locus are included. This demonstrates that AHE probe sets can be tailored to target fewer loci without a significant reduction in BS, allowing future studies to incorporate more taxa at a lower per‐sample sequencing cost. NOC1 shows great promise for resolving long‐standing taxonomic issues and evolutionary questions within arctiine lineages, one of the most speciose clades within Lepidoptera.

Acclimation capacity and rate change through life in the zooplankton Daphnia.

When a change in the environment occurs, organisms can maintain an optimal phenotypic state via plastic, reversible changes to their phenotypes. These adjustments, when occurring within a generation, are described as the process of acclimation. While acclimation has been studied for more than half a century, global environmental change has stimulated renewed interest in quantifying variation in the rate and capacity with which this process occurs, particularly among ectothermic organisms. Yet, despite the likely ecological importance of acclimation capacity and rate, how these traits change throughout life among members of the same species is largely unstudied. Here we investigate these relationships by measuring the acute heat tolerance of the clonally reproducing zooplankter Daphnia magna of different size/age and acclimation status. The heat tolerance of individuals completely acclimated to relatively warm (28°C) or cool (17°C) temperatures diverged during development, indicating that older, larger individuals had a greater capacity to increase heat tolerance. However, when cool acclimated individuals were briefly exposed to the warm temperature (i.e. were ‘heat-hardened'), it was younger, smaller animals with less capacity to acclimate that were able to do so more rapidly because they obtained or came closer to obtaining complete acclimation of heat tolerance. Our results illustrate that within a species, individuals can differ substantially in how rapidly and by how much they can respond to environmental change. We urge greater investigation of the intraspecific relationship between acclimation and development along with further consideration of the factors that might contribute to these enigmatic patterns of phenotypic variation.

Systematics and Taxonomy of Tonatia saurophila Koopman & Williams, 1951 (Chiroptera, Phyllostomidae).

The Stripe-headed Round-eared bat, Tonatia saurophila, includes three subspecies: Tonatia saurophila saurophila (known only from subfossil records in Jamaica), Tonatia saurophila bakeri (distributed from southeastern Mexico to northern Colombia, Venezuela west and north of the Cordillera de Mérida, and northwestern Ecuador), and Tonatia saurophila maresi (distributed in Venezuela east and south of the Cordillera de Mérida, the Guianas, Trinidad and Tobago, northeastern Brazil, and along the upper Amazon basin in Colombia, Ecuador, Peru, and Bolivia). The last two subspecies are an attractive example to test predictions about the historical role of the Andes in mammalian diversification. Based on morphological descriptions, morphometric analyses, and phylogenetic reconstruction using the mitochondrial gene Cyt-b and the nuclear exon RAG2, this study evaluates the intraspecific relationships within Tonatia saurophila and the taxonomic status of the taxon. The three subspecies of T. saurophila are recognizable as full species: Tonatia bakeri, Tonatia maresi, and Tonatia saurophila. The latter is restricted to its type locality and possibly is extinct. Tonatia bakeri, in addition to being larger than T. maresi, is morphologically distinguishable by possessing an acute apex at the posterior edge of the skull, a well-developed clinoid process, and relatively robust mandibular condyles, and by lacking a diastema between the canine and the first lower premolar. The genetic distance between T. bakeri and T. maresi is 7.65%.

How much water is in the tank? An allometric analysis with 205 bromeliad species

Tank bromeliads are prominent and distinctive components of many Neotropical forests. Functionally important for the plants themselves these phytotelms also represent important freshwater habitats in the forest canopy for a range of animal species and other biota. Existing literature values of the amount of water held in these tanks have never been systematically compiled nor has there ever been a systematic assessment of the water holding capacity of bromeliad tanks (tank capacity, TC) with a consistent methodology that covered a large taxonomic breadth of the bromeliad family.We determined TC for more than 200 taxa and collected additional data on total plant dry mass, projected area of the rosette (catchment area), and the number of individual reservoirs for a subset of them. These data were then used to establish intraspecific and interspecific allometric relationships of TC with plant size, the water held in living tissue, and the amount of rain necessary to fill the tank. This paper provides important baseline data for any study of tank function and gives a more modest picture of the “typical” bromeliad tank as often implied by the reference to extreme and unsubstantiated values in the literature.

Genetic differentiation among Psittacanthus rhynchanthus (Loranthaceae) populations: novel phylogeographic patterns in the Mesoamerican tropical lowlands

Historical geological events and climatic changes have played important roles in shaping population differentiation and distribution within species. In this study, we analysed the distribution, expansion and colonization patterns, and genetic differentiation among Psittacanthus rhynchanthus populations in Mesoamerica. Specifically, we determine the effects of major historical events and geographic barriers on population divergence using nuclear and chloroplast DNA sequence data and the impact of Pleistocene glacial cycles on the distribution dynamics of P. rhynchanthus using ecological niche modelling (ENM). Our results showed that P. rhynchanthus populations split into two lineages, one distributed on the Yucatan Peninsula and the second along the Pacific and Atlantic slopes and Honduras, approximately 1 million years ago. The two lineages were fragmented at the last interglacial according to ENM predictions and experienced postglacial range expansion during the Last Glacial Maximum. Analysis of climate differentiation and niche models showed that both lineages have different climatic preferences, where the climatic characteristics of the Yucatan populations are not fully represented in the rest of the distribution range of P. rhynchanthus. Additionally, our study suggests that Pleistocene expansion of suitable habitat, environmental segregation (ecological barrier between regions) and, perhaps host shifts, have acted as the isolation mechanisms between the two lineages. Our results provide new insight as to understanding the distribution and phylogeographic patterns and the possible mechanisms underlying intraspecific evolutionary relationships of plants in the Mesoamerican tropical lowlands.

水分和种植密度对干热河谷车桑子生长性状及种内相互关系的影响

PDF HTML阅读 XML下载 导出引用 引用提醒 水分和种植密度对干热河谷车桑子生长性状及种内相互关系的影响 DOI: 10.5846/stxb202002130246 作者: 作者单位: 作者简介: 通讯作者: 中图分类号: 基金项目: 国家重点研发计划项目（2018YFD0200502）；绵阳师范学院生态安全与保护四川省重点实验室开放基金项目（ESP1901）；绵阳师范学院科研启动项目（QD2019A04） Effects of water and planting density on the growth characteristics and intraspecific relationships of Dodonaea viscosa in a dry-hot valley Author: Affiliation: Fund Project: 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:水分是干热河谷植物生长过程中最主要的限制因子，种植密度增加也会引起植物生长的资源限制，两者交互作用下植物生长性状及种内关系的变化特征还不清楚。以干热河谷优势植物——车桑子为研究对象，根据元谋干热河谷年均生长季降雨量设置3种水分梯度：高水分、中水分和低水分，同时在各水分梯度下设置4个种植密度：1、2、4、9株/盆，探究水分、种植密度及其交互作用对车桑子生长性状、生物量分配及种内相互作用的影响。结果表明：（1）低水分条件下，车桑子生长和水分生理受到抑制，但车桑子在较低的叶水势下依然能够保持较高的相对含水量；（2）干旱胁迫显著降低了车桑子总生物量和单株生物量，显著增加了枯叶生物量比例，低水分和中水分条件下，增加种植密度对总生物无显著影响；而高水分条件下，增加种植密度显著提高了车桑子总生物量；（3）低水分显著增加了茎、叶生物量的异速生长指数，将更多生物量分配到叶，而种植密度增加显著降低了茎、叶生物量的异速生长指数，增加了茎的生物量分配；（4）通过相对邻体效应的计算，各处理条件下，车桑子种内关系均表现为竞争作用，并且，这种竞争作用的强度随水分的减少和密度的增加而增加。在高密度条件下（9棵/盆），增加水分不会减轻种内竞争作用。综上，水分和种植密度均会对车桑子个体的生理生长产生影响，在植被恢复过程中，应考虑水分和种植密度对车桑子个体产生的资源限制作用。 Abstract:Water is the most important limiting factor in the growth of plants in dry-hot valleys; furthermore, the increase in planting density also causes resource limitation in plant growth. However, the interactive effects of water and planting density on plant growth characteristics and intraspecific relationships are not clear. In this study, Dodonaea viscosa, a dominant species in dry-hot valleys was used as the research subject. According to the rainfall during the growing season of Yuanmou dry-hot valley, D. viscosa was planted with three water levels (high water, medium water, and low water) and at four densities (1, 2, 4, and 9 plants/pot) to explore the influence of water, planting density, and their interaction on growth, biomass accumulation, and intraspecific interaction of D. viscosa. The results showed that (1) under the low-water treatment, the growth and water physiology of D. viscosa were inhibited, but the relative water content was still high when the leaf water potential decreased greatly. (2) Drought stress significantly reduced the total biomass and individual biomass and significantly increased the proportion of litter biomass. Under the low-water and medium-water treatments, the increase in planting density had no significant effect on total biomass, whereas under the high-water treatment, the increase in planting density significantly improved total biomass of D. viscosa. (3) The allometric exponent of stem biomass and leaf biomass was significantly greater under the low-water treatment, which indicated relatively more biomass was allocated to leaves, and the allometric exponent decreased under high-planting density. (4) The intraspecific relationship of D. viscosa exhibited a competitive effect, and the intensity of the competitive effect increased with decreased water content and increased with an increase in planting density. Under the high-density treatment (9 plants/pot), increasing water content did not reduce the competitive effect. In conclusion, both water and planting density affected the growth and physiological characteristics of D. viscosa. In the process of vegetation restoration, the effect of water and planting density on resource constraints of D. viscosa should be considered. 参考文献 相似文献 引证文献

Phylogeny and biogeography of the Pleistocene Holarctic steppe and semi-desert goosefoot plant Krascheninnikovia ceratoides

Krascheninnikovia ceratoides (Chenopodiaceae) is a steppe and semi-desert plant with two subspecies, K. ceratoides subsp. ceratoides, which is widespread in Eurasia, and K. ceratoides subsp. lanata, which grows in western and central North America. A few disjunct populations of K. ceratoides subsp. ceratoides are found in Anatolia, Europe and North Africa to the west of its otherwise continuous Eurasian distribution. To understand the evolutionary history of this characteristic steppe and semi-desert plant, we analysed its phylogeny and biogeography. We sequenced several loci including ITS, ETS and the chloroplast intergenic spacer regions atpB-rbcL, rpl32-trnL and trnL-trnF to establish a time-calibrated phylogeny and reconstruct intraspecific relationships. Furthermore, we identified the ploidy level of individuals. While diploid, tetraploid and hexaploid individuals have been reported in the literature, we were only able to find diploids and tetraploids. The diploids were found in the east of Mongolia, Kazakhstan, Kyrgyzstan, Russia and the USA. The tetraploids were located in the west of Mongolia, Kazakhstan, Tajikistan, Russia, and Europe. Populations were uniformly di- or tetraploid. Our results indicate that the species may have spread from the area of Mongolia, northern China and Middle Asia (i.e., the Altai Mountains region) in two opposite directions – on the one hand, diploids migrated to the east, to eastern Asia and North America, and on the other hand diploids and tetraploids migrated to the west, to western Asia and Europe. Fossil-calibrated gene trees were used to estimate the age of the species. Diversification within the species is probably of Pleistocene age. Our dated analysis indicates that the first split among extant lineages of the species took place in the Early Pleistocene (Gelasian). The spread of the main lineages is likely related to major phases of steppe and semi-desert expansions during glacial periods of the Pleistocene.

A biologging perspective to the drivers that shape gregariousness in dusky dolphins

Knowledge of proximate (causation and development) and ultimate (evolution and survival function) causes of gregariousness is necessary to advance our knowledge of animal societies. Delphinids are among the most social taxa; however, fine-scale understanding of their intra-specific relationships is hindered by the need for underwater observations on individuals. We developed a non-invasive animal-borne camera system with the goal of examining influences on gregariousness in dusky dolphins (Lagenorhynchus obscurus). We analyzed video and diving records from 11 individual dusky dolphins off Kaikoura, New Zealand. We examined the influence of biologger attachment on dolphin behavior and tested hypotheses regarding the effects of physiology, predation, and inter-individual variation on conspecific interactions. Dolphins did not exhibit increased rates of descent or ascent in the minutes immediately following biologger attachment, indicating a lack of behavioral response. Respiration rate was positively related to dive depth and duration, suggesting that diving is energetically expensive for this species. Gregariousness was negatively related to dive depth providing evidence that the physiological constraints of diving are likely to limit social behavior. Calves were not observed more frequently in infant (vs. echelon) position with increasing depth, highlighting the likelihood of other anti-predation strategies (e.g., dilution effect) in mother-calf pairs. We found that gregariousness differed between individuals within similar social groups, suggesting the importance of collecting data at the individual level. The evidence presented herein suggests that the further development of animal-borne camera systems will yield further insight into the mechanisms underlying delphinid social behavior. Dolphins are highly social and thus excellent model species for examining the cause and function of gregariousness. However, their cryptic nature poses a challenge to collecting the fine-scale data at the individual level required to conduct rigorous hypothesis tests. We overcame this obstacle by deploying a non-invasive cutting-edge biologger on free-ranging dusky dolphins to collect information on diving behavior, physiology, gregariousness, and mother-calf strategies. Results indicate that diving is energetically expensive, even to relatively shallow depths, and these costs likely hinder gregariousness at depth. Individual differences in gregariousness were apparent and as expected in this fission-fusion society. Unexpectedly, mother-calf pairs appeared to utilize strategies other than spatial positioning to minimize predation risk. This study advanced knowledge of dolphin social life and helps to improve the degree of data resolution in cetaceans to a level on par with terrestrial studies.