1. Kānuka (Kunzea serotina, Myrtaceae) dryland shrubland communities of the lowland plains of South Island (Te Wai Pounamu) New Zealand (Aoteoroa) contain a ground cover largely consisting of mosses, predominantly Hypnum cupressiforme. There has been no previous study of the role of mosses in this threatened habitat which is currently being restored within a contemporary irrigated and intensively-farmed landscape that may be incompatible with this component of the ecosystem. 2. The aim of the present study was to investigate the influence of moss ground cover on hydrology, nitrogen (N) availability and vascular plant interactions, and in relation to nutrient spillover from adjacent farmland. Experimental work was a combination of glasshouse experiments and field-based studies. 3. Extremes of soil temperature and moisture were found to be mediated by the moss carpet, which also influenced N speciation; available N declined with moss depth. The moss layer decreased the amount of germination and establishment of vascular plants but, in some cases, enhanced their growth. Spillover of mineral nitrogen and phosphate from farmland enhanced invasion of exotic grasses which may have benefited from conditions provided by the moss carpet. 4. Synthesis: We found the moss layer to be crucial to ecosystem functioning in these dry habitats with low nutrient substrate. However, when the moss layer is accompanied by nutrient spillover it has the potential to increase exotic weed encroachment. Our results emphasise the importance of non-vascular plant inclusion in restoration schemes but also highlights the importance of mitigating for nutrient spillover.
Seminal fluid proteins (SFPs) play vital roles for optimizing reproductive success in diverse animals. Underlining their significance, SFP production and transfer are highly plastic, e.g., depending on the presence of rivals or mating status of partners. However, surprisingly little is known about replenishing SFPs after mating. It is especially relevant in multiple mating species, as they would continuously produce and use SFPs throughout their reproductive life. Here we examined the expression pattern of SFP genes after mating in the great pond snail, Lymnaea stagnalis. Our results show that three out of the six SFP genes investigated here were up-regulated after mating, indicating that L. stagnalis replenishes seminal fluid in a protein-specific manner. In addition, we suggest that SFP replenishment is plastic depending on the mating history of female-acting snails. Our results shed light on unexplored aspects of SFP replenishment, thereby expanding the understanding of reproductive strategies in animals.
The reintroduction of endangered plant species is an essential conservation tool. Reintroductions can fail to create resilient, self-sustaining populations due to a poor understanding of environmental factors that limit or promote plant success. Biotic factors, specifically plant-arthropod interactions, have been shown to affect the establishment of endangered plant populations. Lupinus nipomensis (Nipomo Mesa lupine) is a state of California (California Rare Plant Rank: 1B.1) and federally (65 FR 14888) endangered endemic plant with only one extant population located along the central California coast. How arthropods positively or negatively interact with L. nipomensis is not well known and more information could aid conservation efforts. We conducted arthropod surveys of the entire L. nipomensis extant population in spring 2017. Observed arthropods present on L. nipomensis included 17 families, with a majority of individuals belonging to Thripidae. We did not detect any obvious pollinators of L. nipomensis, providing support for previous studies suggesting this lupine is capable of self-pollinating, and observed several arthropod genera that could potentially impact the reproductive success of L. nipomensis via incidental pollination or plant predation.
The subphylum Myriapoda included four extant classes (Chilopoda, Symphyla, Diplopoda and Pauropoda), but very little work has been done to explore their phylogenetic relationships. Herein, we determined the complete mitochondrial genome of Polydesmus sp. GZCS-2019 (Myriapoda: Polydesmida) and the mitochondrial genomes are circular molecules of 15,036 bp, with all genes encoded on + strand. The A+T content is 66.1%, making the chain asymmetric, and exhibits negative AT-skew (-0.236). Several genes rearrangements were detected and we propose a new rearrangement model: “TD (N\R) L + C” based on the genome-scale duplication + (non-random/random) loss + recombination. Phylogenetic analyses demonstrated that Chilopoda and Symphyla both were monophyletic group, whereas Pauropoda was embedded in Diplopoda to form the Dignatha. Divergence time showed the first split of Myriapoda occurred between the Chilopoda and other classes (Wenlock period of Silurian). We combine phylogenetic analysis, divergence time, and gene arrangement to yield valuable insights into the evolutionary history and classification relationship of Myriapoda and these results support a monophyletic Progoneata and the relationship (Chilopoda + (Symphyla + (Diplopoda + Pauropoda))) within Myriapod. Our results help to better explain the gene rearrangement events of the invertebrate mitogenome and lay the foundation for further phylogenetic study of Myriapoda.
This study compared the microhabitat use, daily activity pattern and diet of Liolaemus etheridgei Laurent 1998 in two Polylepis woodlands: El Simbral (fragmented) and Tuctumpaya (unfragmented), in Arequipa, Southern Peru. In both populations, we did not detect positive selection for any microhabitat; however, the population at El Simbral showed a negative selection for Polylepys trees while the Tuctumpaya population showed negative selection for Polylepis trees and non-thorny bushes. In El Simbral, active individuals were detected between 9:00 and 15:59h, whereas in Tuctumpaya, we detected active individuals from 8:00 to 17:59h. In both populations, observations of active individuals dropped between 11:00 and 11:59h. We recorded 17 and 23 prey categories in the El Simbral and Tuctumpaya populations respectively. The most important animal prey category in each population was found to be Lygaeidae: Hemiptera, and was the only animal prey category that was selected for in El Simbral and Tuctumpaya. In addition, due to the proportions of plant material found, the El Simbral was found to be omnivorous, whereas the Tuctumpaya population was herbivorous. Trophic niche breadth was broader in Tuctumpaya (B_a= 0.202) than the El Simbral (B_a= 0.147) population, despite there being no significant differences in diet (Permanova: F = 1.036, P = 0.409, permutations = 9999), which is coherent with the high value of trophic niche overlap (O_(j,k) = 0.963). Our compiled data reveal that L. etheridgei shows no selection for any of the resources we define in Polylepis woodlands, on the contrary, it selects negatively against Polylepis trees and non-thorny bushes. The daily activity patterns indicate a bimodal pattern with peaks at 9:00-10:59 and 13:00-13:59 h. The diet of L. etheridgei consists mainly of plants (%W: 66.373), and the most important animal prey category is Lygaeidae: Hemiptera (%IRI = 55.3), which is selected positively.
Species traits influence their response to environmental conditions and the match between phenotypes and environment mediates spatial changes in species composition. These trait-environment linkages can be disrupted in human-modified landscapes. Human land-use creates habitat fragments where dispersal limitation or edge effects can exclude species that may otherwise suit a given macro-scale environment. Furthermore, stressful micro-environments in fragments may limit viable trait combinations resulting in stronger trait covariance compared to contiguous forest, especially in harsher macroenvironments. In a wet tropical forest landscape in the Western Ghats Biodiversity Hotspot of peninsular India, I compared fragments with adjacent contiguous forest for signatures of trait-mediated assembly of tree communities along macroenvironmental gradients. Using four key plant traits—seed size, specific leaf area (SLA), wood density, and maximum height—I evaluated changes in trait-mediated abundances and trait covariance across environmental gradients. Trait-mediated abundances primarily changed along the elevation gradient in contiguous forest, smaller-seeded, shorter, thinner-leaved species increased at higher elevations. In fragments, higher SLA species increased in more seasonal climate and decreased with higher precipitation, and larger seeds decreased at warmer sites. However, traits only weakly predicted abundances and only contiguous forests experienced significant compositional change via traits, driven by trait syndromes varying along a composite environmental gradient defined by elevation, water deficit, and soil C:N ratio. Covariance of seed size and maximum height along gradients of precipitation and temperature revealed divergent constraints on viable phenotypes in fragments and contiguous forest. Notably, local biotic conditions (functional diversity) had stronger effects than environment in explaining trait covariance. Overall, the results imply that trait syndromes and trait covariance, rather than single traits, determine the phenotypes best suited to different macroenvironmental conditions and should inform management or restoration goals in fragments.
The impact of rising global temperatures on survival and reproduction is putting many species at risk of extinction. In particular, it has recently been shown that thermal effects on reproduction, especially limits to male fertility, can underpin species distributions in insects. However, the physiological factors influencing fertility at high temperatures are poorly understood. Key factors that affect somatic thermal tolerance such as hardening, the ability to phenotypically increase thermal tolerance after a mild heat shock, and the differential impact of temperature on different life stages, are largely unexplored for thermal fertility tolerance. Here, we examine the impact of high temperatures on male fertility in the cosmopolitan fruit fly Drosophila virilis. We first determined whether temperature stress at either the pupal or adult life-history stage impacts fertility. We then tested the capacity for heat-hardening to mitigate heat-induced sterility. We found that thermal stress reduces fertility in different ways in pupae and adults. Pupal heat stress delays sexual maturity, whereas males heated as adults can reproduce initially following heat stress, but lose the ability to produce offspring. We also found evidence that while heat-hardening in D. virilis can improve high temperature survival, there is no significant protective impact of this same hardening treatment on fertility. These results suggest that males may be unable to prevent the costs of high temperature stress on fertility through heat-hardening which limits a species' ability to quickly and effectively reduce fertility loss in the face of short-term high temperature events.
Climate change has the potential to alter plant reproductive success directly and indirectly through disruptions in animal pollination. Climate models project altered seasonal precipitation patterns and thus the effects of climate change on available resources and pollination services will depend on the season. Plants have evolved reproductive strategies to minimize pollen and resource limitations, and therefore we expect that the disruption of climate change might cause plants to be more pollen limited in seasons that become wetter than they were historically. In this study, we conducted a pollen supplementation experiment within the Global Change Experiment Facility (GCEF) in Central Germany. The GCEF experimentally manipulates future climate based on a realistic scenario of climate change for the region (drier summers and wetter springs and falls) in a native grassland ecosystem. We quantified seed production of two perennial species Dianthus carthusianorum and Scabiosa ochroleuca in response to pollination treatments (control, supplement), climate treatments (ambient and future) and season (summer and fall). Dianthus carthusianorum produced more seeds in future climate conditions independent of the season, but only when given supplemental pollen. Both species showed an increased reproduction in summer compared to the fall. We did not find any evidence for our expectation of higher pollen limitation in the future climate and fall season (i.e. no three-way interaction pollination x season x climate), which might be explained by the high drought tolerance and generalized pollination of our focal plant species. We conclude that plant reproductive success might be limited by the services of animal pollinators in future climates, and have many suggestions for future studies that are necessary to understand the context-dependence and underlying mechanisms of plant reproductive responses to climate.
The trade-off between within-host infection load and transmission to new hosts is predicted to constrain pathogen evolution, and to maintain polymorphism in pathogen populations. The life-history stages and their correlations that underpin infection development may change under coinfection with other parasites as they compete for the same limited host resources. Cross-kingdom interactions are common among pathogens in both natural and cultivated systems yet their impact on disease ecology and evolution are rarely studied. Host plant Plantago lanceolata is naturally infected by both Phompopsis subordinaria, a seed killing fungus, as well as Plantago lanceolata latent virus (PlLV) in the Åland Islands, SW Finland. We performed an inoculation assay to test whether coinfection with PlLV affects performance of two P. subordinaria strains, and the correlation between within-host infection load and transmission potential. The strains differed in the measured life-history traits and their correlations. Moreover, we found that under virus coinfection, within-host infection load of P. subordinaria was lower but transmission potential was higher compared to strains under single infection. The negative correlation between within-host infection load and transmission potential detected under single infection became positive under coinfection with PlLV. In wild populations, within-host infection load was positively associated with within-population disease prevalence. Jointly, our results suggest that the trade-off between within-host infection load and transmission may be strain specific, and that the pathogen life-history that underpin epidemics may change depending on the diversity of infection, generating variation in disease dynamics.
The characteristics of macroinvertebrate community structure can effectively reflect the health status of lake ecosystem and the quality of the lake ecological environment. It is of great significance to identify the limiting factors of macroinvertebrate community structure for the maintenance of lake ecosystem health. In this study, the community composition of macroinvertebrate assemblages and their relationships with environmental variables in 13 small lakes within Linhuan Lake was investigated. Self-organizing map, K-means clustering analysis, principal component analysis, pearson correlation analysis, and redundancy analysis were used to analyze the correlation and variability between macroinvertebrates community index and environmental factors. The results showed that the environmental variables (pH, total phosphorus, nitrate, water temperature, dissolved oxygen, conductivity, chemical oxygen demand, and ammonium) had a significant effect on the classification of macroinvertebrate community. Molluscs were significantly negatively correlated with pH and chlorophyll a, while annelids and aquatic insects were significantly positively correlated with chlorophyll a and dissolved oxygen. Species richness and Shannon’s diversity of macroinvertebrates were significantly negatively correlated with total phosphorus while biomass of macroinvertebrates was significantly negatively correlated with pH. High alkalinity characteristics and eutrophication of the lake have a serious impact on the macroinvertebrate community. Human interference and unreasonable industrial and surface runoff from agricultural farms destroy the ecological environment and affect the community structure of macroinvertebrate. Thus, the improvement of the macroinvertebrate’s community structure should be carried out by improving the Lianhuan Lake watershed ecological environment and controlling watershed environmental pollution.
Investigating the determinants of reproductive biology of fishes is an essential component of biological research. Breeding pattern was investigated to determine the impact of exotic Oreochromis niloticus on the native congeneric Oreochromis macrochir in the upper Kabompo River. Gonado-somatic index and sex ratio was used to investigate the breeding pattern in both invaded (where O. niloticus is present) and uninvaded (where O. niloticus is absent) sections of the river. Oreochromis macrochir was the only native congeneric species found in both sections. Results showed that the overall gonado-somatic index means for both sexes of O. macrochir in both sections were similar. For O. niloticus in invaded section indicated all year reproduction though reduced spawning in cold season (May-June), but with increased spawning activity in wet season (February-March). In O. macrochir, males and females were found breeding in both dry and wet seasons only, as for cold season no reproduction was recorded. Sex ratio (females: males) was 1:1.3 and 1:1.7 for O. niloticus and O. macrochir respectively, and both significantly deviated from the sex ratio of 1:1 (ꭓ2=8.42 and 9.37; p<0.05). Oreochromis niloticus formed the most abundant fish caught 221(63.5%) than O. macrochir 127(36.5%). Our study has revealed that O. niloticus was able to spawn in all seasons with 23% higher breeding population than O. macrochir, which explains the suppression in the abundance. We expect O. niloticus to invade further downstream of the Kabompo River due to natural dispersion.
Abstract Predator/Parasitoid functional response is one of the main tools used to study predation behaviour, and in assessing the potential of biological control candidates. It is generally accepted that predator learning in prey searching and manipulation can produce the appearance of type III functional response. Holling proposed that in the presence of alternative prey, at some point the predator would shift the preferred prey, leading to the appearance of a sigmoid function that characterized that functional response. This is supported by the analogy between enzyme kinetics and functional response that Holling used as the basis for developing this theory. However, after several decades, sigmoidal functional responses appear in the absence of alternative prey in most of the biological taxa studied. Here, we propose modelling the effect of learning on the functional response by using the explicit incorporation of learning curves in the parameters of the Holling functional response, the attack rate (a), and the manipulation time (h). We then study how the variation in the parameters of the learning curves causes variations in the shape of the functional response curve. We found that the functional response product of learning can be either type I, II or III, depending on what parameters act on the organism, and how much it can learn throughout the length of the study. Therefore the presence of other types of curves should not be automatically associated with the absence of learning. These results are important from an ecological point of view because when type III functional response is associated with learning, it is generally accepted that it can operate as a stabilizing factor in population dynamics. Our results, to the contrary, suggest that depending on how it acts, it may even be destabilizing by generating the appearance of functional responses close to type I.
Movement and demographic rates are critical to the persistence of populations in space and time. Despite their importance, estimates of these processes are often derived from a limited number of populations spanning broad habitat or environmental gradients. With increasing appreciation of the role fine-scale environmental variation in microgeographic adaptation, there is need and value to assessing within-site variation in movement, growth, and demographic rates. In this study, we analyze three years of spatial capture-recapture data collected from a mixed-use deciduous forest site in central Ohio, USA. Study plots were situated in mature forest on a slope and in successional forest on a ridge but were separated by less than 100-m distance. Our data showed that the density of salamanders was less on ridges, which corresponded with greater distance between nearest neighbors, less overlap in core use areas, greater space-use, and greater shifts in activity centers when compared to salamander occupying the slope habitat. However, these differences were moderate. In contrast, we estimated growth rates of salamanders occupying the ridge to be significantly greater than salamander on the slope. These differences result in ridge salamanders reaching maturity more than one year earlier than slope salamanders, increasing their lifetime fecundity by as much as 43%. The patterns we observed in space use and growth are likely the result of density-dependent processes, reflecting differences in resource availability or quality. Our study highlights how fine-scale, within-site, variation can shape population demographics. As research into the demographic and population consequences of climate change and habitat loss and alteration continue, future research should take care to acknowledge the role that fine-scale variation may play, especially for organisms with small home ranges or limited vagility.
Research that has been conducted documenting species richness patterns on tropical mountains has resulted in conflicting observations: monotonic declines with increasing elevation, monotonic increase with increasing elevation, and a mid-elevation ‘bulge.’ Currently, it is unclear if these differences are due to environmental differences associated with the various study areas, the taxonomic groups or ecological groups (e.g., growth form) sampled, or the scale of the study area along an elevation gradient. Because of the difficulty in sampling and identifying canopy-dwelling plants, the number of inventories quantifying tropical epiphytes is relatively limited and recent. In this study, we provide a detailed qualitative and quantitative assessment of the vascular epiphyte flora and its spatial distribution on Volcán Maderas, Isla de Ometepe, Nicaragua, including weather and environmental measurements along the entire elevation gradient of the volcano. We sampled epiphytes in five distinct forest types associated with increasing elevation as follows: dry forest, humid forest, wet forest, cloud forest, and elfin forest Five weather stations were placed along the elevation gradient for us to relate observed patterns to environmental conditions. A hump-shaped species richness pattern was detected for all vascular epiphytes at approximately 1000 m in elevation (cloud forest), yet species abundance increased with increasing elevation. In total we obtained 206 unique species identifications of vascular epiphytes belonging to 26 families and 73 genera. The most species-rich family was the Orchidaceae with 55 species for the entire elevation gradient, followed by Bromeliaceae (29 species), Araceae (23), Polypodiaceae (25), Dryopteridaceae (16), and Piperaceae (11), with all other families respresented by fewer than 10 species each. We found that richness patterns differ phylogenetically within epiphytes, possibly due to different adaptive strategies, and species for the most part appear to be narrowly distributed within specific habitat zones along the elevation gradient.
Habitat alterations that often accompany land-use change are one of the major drivers of global biodiversity losses. In Africa, these threats are especially severe, as this continent has the most rapidly growing of all human populations. Inevitably, increasing areas of land are being transformed for agriculture, including drought-prone drylands in southern and central Africa, despite often having poor soils. In Zimbabwe, a land reform programme provided a unique opportunity to study the biodiversity response to abrupt habitat modification in an extensive dryland area of mixed grassland and woodland savannah. Small-scale subsistence farms were created rapidly during 2001-2002 in formerly semi-natural savannah. We measured the changing compositions of bird communities in transformed and untransformed land over an 8-year period, commencing one decade after subsistence farms were established. Over the study period, repeated counts were made along identical transects in order to assess species' population changes that may have resulted from trait-filtering responses to habitat disturbance. We recorded significantly increased abundances in both land-use areas, accompanied by increases in species diversity and functional redundancy. Temporal trends showed increased abundances across all feeding guilds, and in species of virtually all sizes. Influxes of new species did not increase functional traits' diversity, and no species with distinctive traits appear to have been lost as a result of land-use change. Nearly two decades after habitat transformation, the bird communities in the transformed and untransformed areas had become more similar in composition. The broadly benign impact on birds of land conversion into subsistence farms is attributed to the relatively low-level of human activities and disturbance in the transformed land, and the large regional pool of non-specialist bird species.
In land plants, heteroblasty broadly refers to a drastic change in morphology during growth through ontogeny. Juniperus flaccida and Pinus cembroides are conifers of independent lineages known to exhibit leaf heteroblasty between the juvenile and adult life stage of development. Juvenile leaves of P. cembroides develop spirally on the main stem and appear decurrent, flattened and needle-like; whereas, adult photosynthetic leaves are triangular or semi-circular needle-like, and grow in whorls on secondary or tertiary compact dwarf shoots. By comparison, J. flaccida juvenile leaves are decurrent and needle-like, and adult leaves are compact, short and scale-like. Comparative analyses were performed to evaluate differences in anatomy and gene expression patterns between developmental phases in both species. RNA from twelve samples was sequenced and analyzed with available software. They were assembled de novo from the RNA-Seq reads. Following assembly, 63,741 high quality transcripts were functionally annotated in P. cembroides and 69,448 in J. flaccida. Evaluation of the orthologous groups yielded 4,140 shared gene families among the four references (adult and juvenile from each species). Activities related to cell division and development were more abundant in juveniles than adults in P. cembroides, and more abundant in adults than juveniles in J. flaccida. Overall, there were 509 up-regulated and 81 down-regulated genes in the juvenile condition of P. cembroides and 18 up-regulated and 20 down-regulated in J. flaccida. Gene interaction network analysis showed evidence of co-expression and co-localization of up-regulated genes involved in cell wall and cuticle formation, development, and phenylpropanoid pathway, in juvenile P. cembroides leaves. Whereas in J. flaccida, differential expression and gene interaction patterns were detected in genes involved in photosynthesis and chloroplast biogenesis. Although J. flaccida and P. cembroides both exhibit leaf heteroblastic development, little overlap was detected and unique genes and pathways were highlighted in this study.
Because of their range expansion across North America, coyotes (Canis latrans) now occur sympatrically with numerous other predator species, including red foxes (Vulpes vulpes). This raises several interesting ecological questions, including if and how sympatry affects the diet and gut microbiomes of coyotes and red foxes. We examined the gut microbiomes of sympatric populations of coyotes and red foxes within two different National Parks in Virginia, USA, that differ in land use, vegetation, and anthropogenic disturbance: Prince William Forest Park (PRWI) and Manassas National Battlefield Park (MANA). From 2012 to 2017, scat samples from PRWI and MANA were collected and analyzed. Polymerase Chain Reaction (PCR) amplification of a region of the mitochondrial cytochrome-b gene followed by restriction enzyme digestion of the PCR product was used to determine the origin of each scat sample. Next-Generation DNA sequencing of a hypervariable 16S rRNA gene region was used to determine gut microbiome information about the scat samples. There was no evidence for a difference between the gut microbiomes of red foxes in either location, or for a difference between the gut microbiomes of red foxes at either location and coyotes at the location with lower human disturbance, PRWI. However, the gut microbiomes of coyotes at the location with higher anthropogenic disturbances, MANA, revealed a marked change from those found in red foxes at either location and from those in coyotes at the location with lower disturbances. The gut microbiomes of coyotes subjected to greater human impact revealed clear evidence of dysbiosis, indicative of increased physiological stress and reduced health. We discuss our observations in the context of understanding anthropogenic impacts on coyote and red fox interactions. Our results suggest that physiological stress in the form of human disturbance may play an important role in the composition of the gut microbiome of coyotes, which can affect their overall health.
Climate effects habitat and define species physiology. Climatic regimes were different in past and adaptability of different species varied. Climate change causes certain stress on animal, recorded as Enamel Hypoplasia (EH). Proboscideans, the mega herbivores were extensively represented in the Siwaliks of Pakistan between Middle Miocene to Pleistocene (~15.2 – ~1.0Ma). The study is carried out on 15 species from 9 genera and 4 families using 319 teeth from 266 individual quarries. Our results revealed 20.06% (64/319) teeth infected by EH. Family Deinotheriidae faced higher stress during the terminal of middle Miocene (EH 25%). Dental structure indicate that this family preferred soft vegetation like C3 plants and failed to survive in grassland ecology at the onset of Late Miocene (~10-9 Ma). Gomphotheriids (EH 21.05%) and Stegodontids (EH 23.40%) survived through warm and dry climatic conditions of the Late Miocene, but could not survive the cool and dry climate of Plio-Pleistocene where grasslands were abundant with less browsing activity. Family Elephantidae (EH 8.75%) was successful in drier conditions, and utilized the exclusive C4 diet in open grasslands as efficient grazers, indicated by their tooth morphology. Elephantids were dominant of the proboscideans in open grassland and drier climate during Plio-Pleistocene in Indian subcontinent. We assume that change in the Siwalik climate was governed by microclimate as in the present day Siwaliks grasslands are widely distributed at low altitudes with lower mean annual precipitation and forestlands still persist in Myanmar and Nepal which receives more rainfall and have lower mean annual temperature.