Life histories of closely related amphidromous and non‐migratory fish species: a trade‐off between egg size and fecundity

相似文献   

Theoretical habitat templets, species traits, and species richness: Plecoptera and Ephemeroptera in the Upper Rhône River and its floodplain

• 1 Ephemeroptera and Plecoptera in two sites of the Upper Rhône River (France) were examined using multivariate analyses to determine: (i) relationships among seventeen species traits; (ii) habitat utilization of the fifty-five species present; (iii) the relationship between species traits and habitat utilization; (iv) trends of species traits and species richness in a framework of spatial and temporal habitat variability.
• 2 The species traits having the highest correlation ratios correspond to reproduction or life cycle, behavioural, and morphological characteristics. According to their traits, species of Baetidae, Caenidae, and Leptophlebiidae (Ephemeroptera) are opposite species of Perlidae and Perlodidae (Plecoptera).
• 3 The distribution of species in thirteen habitat types of the Upper Rhône River floodplain demonstrates a transverse gradient from the main channel to the oxbow lakes. Plecoptera are restricted to the different main channel habitats; in contrast, Ephemeroptera families have a broader distribution with Baetidae and Leptophlebiidae occurring in most floodplain habitats.
• 4 Plecoptera exhibit a significant relationship between species traits and habitat utilization but no relationship is evident for Ephemeroptera. Baetidae use many habitat types and have diverse species traits; in contrast, Leptophlebiidae, Heptageniidae, and Caenidae use many habitat types but each family has a rather uniform set of traits.
• 5 Trends in species traits were significantly related to both the spatial and temporal variability of habitats. Considering only temporal variability, the distribution of species trait modalities (= categories) corresponded well to predictions on trends in the river habitat templet for ‘minimum age at reproduction’ and ‘potential longevity’, and in general for ‘descendants per reproductive cycle’, ‘reproductive cycles per year’, ‘potential size’, and ‘body flexibility’ trends in six other traits did not match predictions.
• 6 No trends in species richness were evident in spatial–temporal framework of habitat variability.

     

Relation between temporal persistence of host plants and wing length in leafhoppers (Hemiptera: Auchenorrhyncha)

Abstract.

• 1 Wing form frequencies in 255 populations of 101 species of leafhoppers (Auchenorrhyncha) in temporary and permanent habitats were documented.
• 2 The proportion of brachypterous specimens in the leafhopper assemblages on ruderal host plants in temporary habitats (median 2%, range 0–8%) was significantly lower than that on permanent host plants in undisturbed habitats (median 22%, range 0–94%).
• 3 Leafhopper species typical of temporary habitats were either monomorphic, macropterous, or wing-dimorphic with macropterous forms prevailing in both sexes.
• 4 Among the eighty-nine species recorded in permanent habitats, forty-five species were wing dimorphic. In forty-one dimorphic species, a brachypterous form prevailed. This prevalence was found for both sexes in thirty-one species, for only females in nine species and for only males in one species.
• 5 The prevalence of brachypters in males, but not in females, found in Anoscopus flavostriatus, is probably the first such documented case in Auchenorrhyncha.
• 6 The hypothesis is proposed that in temporary habitats, density-dependent production of macropters in wing dimorphic species is an adaptation to frequent habitat deterioration caused by factors independent of the density of the species.
• 7 The predominance of brachypters in permanent habitats indicates that a density-dependent decrease in fitness usually does not offset the potential decrease in fitness connected with macroptery and dispersal. Because of this inability of leafhopper populations to decrease significantly the quality of their resources, a high population density cannot be used as a predictor of future quality of these resources, which is information essential for efficient dispersal behaviour.

     

Theoretical habitat templets, species traits, and species richness: 548 plant and animal species in the Upper Rhône River and its floodplain

• 1 For practical reasons, conceptual developments in community ecology are usually based on studies of a restricted systematic group. The cooperation of thirty or so specialists in the synthesis of long-term ecological research on the Upper Rhône River, France, provided a unique occasion to investigate relationships among species traits, the habitat utilization by species, the relationship between species traits and habitat utilization, and trends of species traits and species richness in the framework of spatial-temporal habitat variability for 548 species of plants (Hyphomycetes, aquatic macrophytes, floodplain vegetation) and animals (Tricladida, Oligochaeta, several groups of Crustacea, Insecta and Vertebrata).
• 2 Using correspondence analysis, 100 modalities of eighteen species traits were examined; the resulting typology demonstrates that systematic groups are the most important elements for separating species traits such as size, fecundity of individuals, parental care, mobility, body form, and food type. Small species have an intermediate number of descendants per reproductive cycle and few reproductive cycles both per year and per individual; in contrast, large species have a high number of descendants per reproductive cycle and few reproductive cycles per year but many potential reproductive cycles per individual.
• 3 The analysis of habitat utilization in the Upper Rhône River and its floodplain by the 548 species demonstrated a vertical gradient separating interstitial from superficial habitats; a transverse gradient for superficial habitats from the main channel towards more terrestrial ones is also evident.
• 4 Because of a significant (P < 0.01) relationship between species traits and habitat utilization, traits such as size, fecundity of individuals, parental care, tolerance to variation in humidity, and respiration are arranged along the vertical and transverse habitat gradient. Size, the number of reproductive cycles per individual, and the tolerance to variation of humidity increases from permanent waters to temporary waters, aggrading habitats, and terrestrial habitats.
• 5 Species traits showed significant (P < 0.01) trends in the framework of spatial-temporal habitat variability and were compared with predictions based on the river habitat templet. Although each habitat showed a mixture of species traits at low temporal and spatial variability, and at high variability sites, trends corresponded to predictions for three traits (number of descendants per reproductive cycle, number of reproductive cycles per individual, attachment to soil or substrate) along a gradient of increasing temporal habitat variability.
• 6 The species richness of each habitat within the Upper Rhône River and its floodplain significantly (P = 0.03) increased as the spatial variability of habitats increased but there is no statistical correlation between spedes richness and temporal variability. An altemative hypothesis predicting that fewer spedes per resource occur in temporally stable habitats is also not supported.

     

Edge effects on ground beetles at the woodlot–field interface are short‐range and asymmetrical

• 1 Boundaries between woodlots and agricultural habitats are numerous in temperate agricultural landscapes and influence ecological processes in both woodlots and agricultural habitats.
• 2 We aimed to determine how far the species assemblage of ground beetles in woodlot and open habitats was influenced by the presence of the woodlot–field boundary.
• 3 We studied the distribution of ground beetles on both sides of the boundaries of four woodlots along transects of pitfall traps (n = 140). The depth of edge influence (i.e. the distance from the boundary at which the presence of the boundary has no more significant influence) on the species assemblage of ground beetles in each woodlot and in each agricultural habitat was determined with nonlinear canonical analysis of principal coordinates, an ordination method that is followed by nonlinear regression of the principal coordinates on distance from the boundary.
• 4 The depth of edge influence on the species assemblages of ground beetles was asymmetrical relative to the boundary: it was generally higher and had higher variability in open habitats (14.4 ± 12.3 m) than in woodlots (4.9 ± 2.3 m). Species assemblages of ground beetles in edges were a mix between both adjacent species assemblages. Edge effects in woodlots were deeper in the woodlots exhibiting a deeper penetration of open habitat species. Symmetrically, edge effects in open habitat were deeper in the open habitats with a deeper diffusion of forest species into the open habitat.
• 5 Forest ground beetles were not threatened by edge effects. Rather, edge effects are likely to benefit agriculture, mostly through the dispersal of predatory forest species into agricultural fields.

     

Use of agroecosystem matrix habitats by mammalian carnivores (Carnivora): a global‐scale analysis

相似文献   

Temperature‐driven color lightness and body size variation scale to local assemblages of European Odonata but are modified by propensity for dispersal

1. Previous macrophysiological studies suggested that temperature‐driven color lightness and body size variations strongly influence biogeographical patterns in ectotherms. However, these trait–environment relationships scale to local assemblages and the extent to which they can be modified by dispersal remains largely unexplored. We test whether the predictions of the thermal melanism hypothesis and the Bergmann's rule hold for local assemblages. We also assess whether these trait–environment relationships are more important for species adapted to less stable (lentic) habitats, due to their greater dispersal propensity compared to those adapted to stable (lotic) habitats.
2. We quantified the color lightness and body volume of 99 European dragon‐ and damselflies (Odonata) and combined these trait information with survey data for 518 local assemblages across Europe. Based on this continent‐wide yet spatially explicit dataset, we tested for effects temperature and precipitation on the color lightness and body volume of local assemblages and assessed differences in their relative importance and strength between lentic and lotic assemblages, while accounting for spatial and phylogenetic autocorrelation.
3. The color lightness of assemblages of odonates increased, and body size decreased with increasing temperature. Trait–environment relationships in the average and phylogenetic predicted component were equally important for assemblages of both habitat types but were stronger in lentic assemblages when accounting for phylogenetic autocorrelation.
4. Our results show that the mechanism underlying color lightness and body size variations scale to local assemblages, indicating their general importance. These mechanisms were of equal evolutionary significance for lentic and lotic species, but higher dispersal ability seems to enable lentic species to cope better with historical climatic changes. The documented differences between lentic and lotic assemblages also highlight the importance of integrating interactions of thermal adaptations with proxies of the dispersal ability of species into trait‐based models, for improving our understanding of climate‐driven biological responses.

     

Theoretical habitat templets, species traits, and species richness: ostracods (Crustacea) in the Upper Rhône River and its floodplain

• 1 Ostracods occurring at two sections of the Upper Rhône River, France, were examined to determine relationships among species traits, habitat utilization, the relationship between species traits and habitat utilization, and trends in species traits and species richness in the context of spatial and temporal variability of habitats. Twenty regularly sampled species were used in this study and fifteen species traits were considered.
• 2 Throe groups can be distinguished according to their species traits: group 1 has species of mixed sizes with high reproductive rates, short life span, spherical shape, long swimming bristles, low thigmotactism, and high resistance to desiccation; group 2 has medium-sized species with low reproductive rates, long life span, low or no tolerance to desiccation, geometric (trapezoidal, triangular) or streamlined carapace shape, no swimming bristles, and a strong thigmotactism; group 3 has the largest species with parthenogenetic reproduction, medium-sized swimming bristles, and flattened or cylindric carapace shape.
• 3 Ostracod habitat utilization segregates the superficial and interstitial habitats along a gradient from the main channel to the abandoned arms and to the temporary waters.
• 4 The co-structure (= relationship) between species traits and habitat utilization indicates that the species use particular habitats with a particular set of species trait modalities. Species with long life spans, late maturity, low fecundity, and low migratory ability are restricted to the interstitial habitats; the epigean species with long life spans, large size, and parental care are more abundant in permanent flowing and standing surface waters; the epigean species with short life spans, high migratory ability, and high tolerance to desiccation are more abundant in temporary ponds.
• 5 The analyses of the distribution of the species traits in a river habitat templet of spatial and temporal variability emphasized that the main disturbance structuring the Rhône River ostracod assemblage is desiccation.
• 6 Of the trends predicted for species traits in the framework of the river habitat templet, five (size, body form, attachment, reproductive technique, and mobility) are clearly opposite for ostracods (because the predictions were mainly established for flood-related disturbances) but four (life span, number of reproductive cycles per year, age at first reproduction, and desiccation tolerance) are in agreement.
• 7 No trends in ostracod species richness in the framework of spatial–temporal habitat variability were evident.

     

Theoretical habitat templets, species traits, and species richness: Trichoptera in the Upper Rhône River and its floodplain

• 1 For Trichoptera occurring in two sites of the Upper Rhône River (France) we examine: (i) relationships among species traits; (ii) habitat utilization of Trichoptera species; (iii) the relationship between species traits and habitat utilization; (iv) trends of species traits in the framework of spatial–temporal habitat variability to test predictions of the habitat templet concept; and (v) trends of species richness in the framework of spatial–temporal habitat variability to test predictions of the patch dynamics concept.
• 2 Of the sixteen species traits selected, twelve have high correlation ratios for the seventy-five species used in this analysis; these traits are related to behavioural, morphological, or physiological aspects. Traits related to reproduction or life cycle have lower correlation ratios.
• 3 An ordination by species traits separates the five main families into three groups: (i) Hydropsychidae and Polycentropodidae; (ii) Hydroptilidae; and (iii) Leptoceridae and Limnephilidae. An ordination of the habitat utilization of the species in ten habitats indicates that the Hydropsychidae occur preferentially in the main channel, Hydroptilidae, Polycentropodidae, and Limnephilidae occur in backwaters or oxbow lakes, and the Leptoceridae are ubiquitous.
• 4 The Hydropsychidae exhibit a relationship between species traits and habitat utilization, i.e. they use similar habitat types with similar species traits. The species traits of the other four families are similar but their habitat utilization is quite different.
• 5 The Hydropsychidae occur in lowest spatial–temporal variability habitats and Limnephilidae in the highest. Therefore, net spinners and filterers are characteristic of habitats with a low spatial–temporal variability, whereas shredders and case makers using plant material are characteristic of habitats with high spatial–temporal variability. The trends in species traits show little agreement with trends predicted from the river habitat templet.
• 6 Trends of species richness in the framework of spatial and temporal variability do not follow the predictions of the patch dynamics concept because richness is similar in all superficial habitats. This implies that each habitat, in spite of large differences in their spatial and temporal variability, offers Trichoptera a similar but limited number of ecological niches.

     

Arthropod accumulation on tea in young and old habitats

ABSTRACT.

• 1 A comparison is made of the number of species of arthropods that inhabit tea plants in young and old habitats. Tea plants of comparable age harbour more species in old habitats than in young habitats.
• 2 In both young and old habitats, there is an initial rise in the number of arthropod species on young tea upto 11 years: in the intermediate phase, i.e. between 12 and 21 years, a sharp decline in species numbers occurs followed by a rapid increase between 22 and 36 years, and a final drop after 36 years. These phases are characterized by sap-feeding mites and insects; leaf eaters and defoliators; stem and root borers; and termites and wood-eating insects respectively.
• 3 Attracting abilities of the plants of different age-groups vary according to their morphological, and physiological attributes depending on their locations in young and old habitats.
• 4 Diverse species of arthropods coexist on tea by developing their own niches in different parts of plants; they apparently avoid interspecific competition by maintaining their numbers at low density.

     

The biology and ecology of lotic Tardigrada

• 1 Tardigrades comprise a micrometazoan phylum that is a sister group of the arthropods.
• 2 They are components of the meiobenthos in lotic habitats, and ≈ 50–70 species have been reported in such habitats world‐wide. Approximately 800 species have been identified from all marine, freshwater, and terrestrial habitats.
• 3 Taxonomy is based primarily on the morphology of the claws, buccal‐pharyngeal apparatus, cuticle and eggs.
• 4 Reproductive modes include sexual reproduction (amphimixis) and parthenogenesis. The sexual condition of individuals may be either gonochorism, unisexuality, or hermaphroditism. Moulting occurs throughout the life of the tardigrade.
• 5 Latent states (cryptobiosis, including encystment, anoxybiosis, cryobiosis, osmobiosis and anhydrobiosis) enable tardigrades to withstand unfavourable environmental conditions.
• 6 Population densities, life histories, dissemination and biogeography of freshwater species are poorly known.

     

Life history traits related to resource partitioning between synhospitalic species of Colocasiomyia (Diptera, Drosophilidae) breeding in inflorescences of Alocasia odora (Araceae)

Abstract.

• 1 Two closely related species of Colocasiomyia alocasiae (Okada) and C.xenalocasiae (Okada) (Diptera, Drosophilidae) breed in inflorescences of Alocasia odora C. Koch (Araceae), a hermaphroditic understorey clonal herb.
• 2 The two drosophilid species form a synhospitalic pair in Okinawa with alocasiae breeding in the upper half of the inflorescence and xenalocasiae breeding in the lower half.
• 3 C.alocasiae also has the following combination of life history traits: small body size, many eggs, and early reproductive maturity. In contrast, xenalocasiae can be described as having larger body size, fewer eggs, and delayed reproductive maturity.
• 4 Resource partitioning between the two species on the same host may be affected by these life history traits which are associated with their larval habitats.

     

Spatiotemporal dynamics of active flying Diptera predators among different farmland habitats

1. Farmland habitats comprise an arrangement of cropped, uncropped and natural vegetation among the farms. Despite the differences in these habitats' features, generalist highly mobile predators are more likely to explore them in time and space.
2. We investigated the spatiotemporal dynamics of the species of Dolichopodidae (Diptera) in organic vegetable farms because they are one of the most abundant generalist highly mobile predators in Brazilian agroecosystems.
3. We simultaneously sampled the abundance of Condylostylus Bigot and Chrysotus Loew adults (both Dolichopodidae) in the crop, fallow areas, agroforests and forest fragments within five organic farms for 2 years.
4. Predators preferred open-field habitats to agroforests and forest fragments. Probably, open-field habitats present more opportunities to prey foraging, resulting in higher population densities.
5. To the extent that abiotic conditions become more restrictive during the dry season, agroforests and forests act as breeding sites and shelter, thereby maintaining the predators' populations in the overall farmland habitat.
6. Both predatory genera occupy habitats with distinct features across time, forming a dynamic and contiguous population unit within the farm. Therefore, conservation biological control strategies in organic crops should consider the role of agroforests and forest fragments in species conservation beyond the plot level.

     

Theoretical habitat templets, species traits, and species richness: aquatic oligochaetes in the Upper Rhône River and its floodplain

• 1 This paper summarizes twenty years of ecological research on aquatic oligochaetes of the Upper Rhône River and its alluvial floodplain (France). Species traits of fifty species of the ninety taxa recorded from two areas Gons and Brégnier-Cordon) were used to examine the relationships among species traits, habitat utilization of these species, whether a relationship exists between species traits and habitat utilization, and the applicability of predictions from the river habitat templet and the patch dynamics concept in the framework of spatial and temporal habitat variability. We used fourteen habitat types and sixteen species traits in this analysis.
• 2 When examined by correspondence analysis, species traits separate the Naididae (with a higher potential for reproduction, small size, high mobility, and opportunistic diet) from all other families.
• 3 Habitat utilization by oligochaetes demonstrates two gradients: a vertical gradient that arranges species by their affinity for interstitial habitats (stygophily) and a transversal gradient that arranges them by their affinity for main channel habitats (rheophily).
• 4 No significant relationship was found between species traits and habitat utilization in a co-inertia analysis.
• 5 Trends observed for species traits within the framework of spatial-temporal habitat variability show only minor agreement with predictions of the river habitat templet.
• 6 Species richness is generally higher in superficial and interstitial habitats that are permanently connected with the main channel, and peaks in the superficial parapotamons (backwaters that are permanently connected with the main channel) characterized by intermediate levels of spatial as well as temporal variability; this pattern only partially fits with predictions of the patch dynamics concept.

     

Theoretical habitat templets, species traits, and species richness: aquatic Coleoptera in the Upper Rhône River and its floodplain

• 1 To test predictions of the river habitat templet and the patch dynamics concept, trends in species traits and species richness of aquatic beetles were related to the spatial-temporal variability of eighteen habitat types in the alluvial floodplain of the French Upper Rhône River. One hundred and twenty species of beetles were used in this analysis.
• 2 The basic information was obtained either from the literature (for most of the species traits) or from observations made at approximately 500 sampling sites in the Brégnier-Cordon and Jons sections over the past 19 years (for habitat utilization). This information was structured by a fuzzy coding technique and examined by ordination analyses.
• 3 Analyses of the relationships among nineteen species traits revealed a clear distinction according to traits such as body form (for adults), functional feeding type and food (adults and larvae), attachment to the substrate and dissemination potential (adults and larvae), and patterns of aquatic and/or terrestrial life of adults and larvae. Species traits such as number of descendants per reproductive cycle, and number of reproductive cycles per year or per individual showed less contrast, because these traits are rather homogeneous in aquatic beetles.
• 4 Analyses of the habitat utilization by the aquatic beetles revealed a vertical gradient that separates interstitial from superficial habitats, and a transverse gradient for the superficial habitats, which extends from the main channel towards permanent oxbow lakes and temporary waters.
• 5 The significant relationship betweeen species traits and habitat utilization demonstrates that most beetle species use a particular set of habitat types with a particular set of species trait modalities.
• 6 Species traits of aquatic beetles are homogeneous but evidently very successful and are adapted to many potential conditions of spatial–temporal variability. Because of this homogeneity, observations on aquatic beetles do not support trends of traits in the framework of spatial–temporal variability predicted from the river habitat templet.
• 7 The observed species richness of aquatic beetles is low in habitat types with a low spatial–temporal variability, increases as spatial variability increases, and tends to be highest at intermediate temporal variability. This pattern matches predictions of the patch dynamics concept.

     

Community science data suggests that urbanization and forest habitat loss threaten aphidophagous native lady beetles

1. Community scientists have illustrated rapid declines of several aphidophagous lady beetle (Coccinellidae) species. These declines coincide with the establishment of alien coccinellids. We established the Buckeye Lady Beetle Blitz program to measure the seasonal occupancy of coccinellids within gardens across a wide range of landscape contexts. Following the Habitat Compression Hypothesis, we predicted that gardens within agricultural landscapes would be alien‐dominated, whereas captures of natives would be higher within landscapes encompassing a high concentration of natural habitat.
2. Within the state of Ohio, USA, community scientists collected lady beetles for a 7‐day period across 4 years in June and August using yellow sticky card traps. All identifications were verified by professional scientists and beetles were classified by three traits: status (alien or native), mean body length, and primary diet. We compared the relative abundance and diversity of coccinellids seasonally and determined if the distribution of beetles by size, status, and diet was related to landscape features.
3. Alien species dominated the aphidophagous fauna. Native aphidophagous coccinellid abundance was positively correlated with forest habitat while alien species were more common when gardens were embedded within agricultural landscapes. Urbanization was negatively associated with both aphidophagous alien and native coccinellids.
4. Synthesis and Applications: Our census of native coccinellid species within residential gardens—a widespread and understudied habitat—was enabled by volunteers. These data will serve as an important baseline to track future changes within coccinellid communities within this region. We found that native coccinellid species richness and native aphidophagous coccinellid abundance in gardens were positively associated with forest habitat at a landscape scale of 2 km. However, our understanding of when and why (overwintering, summer foraging, or both) forest habitats are important remains unclear. Our findings highlight the need to understand how declining aphidophagous native species utilize forest habitats as a conservation priority.

     

Floral resources,body size,and surrounding landscape influence bee community assemblages in oak‐savannah fragments

相似文献   

Effects of an invasive crayfish on the littoral macroinvertebrates of large boreal lakes are habitat specific

相似文献   

Better desiccated than eaten by fish: Distribution of anurans among habitats with different risks to offspring

1. Freshwater species with complex life cycles face a trade-off between the risks of offspring mortality due to desiccation in temporary habitats and due to predators common in long-duration habitats, especially fish. In real-world conditions, intermediate-gradient areas that are highly suitable for some ecological specialists are often limited. I examined the relative significance of drivers of the permanence–predation gradient in habitat selection by pond-breeding anurans.
2. Anuran oviposition was investigated at the community level in fish pond landscapes with only three types of habitat, permanent fish-containing ponds and highly desiccation-prone pools, either fishless or recently emptied of fish and with fish odour (fish cue). Altogether, 65 ponds/pools, interspersed in four clusters, were examined for the presence of egg masses.
3. Bufo bufo was the only species preferring permanent ponds. Egg masses of Rana sp. (Rana arvalis/Rana temporaria) occurred in all fishless pools, and less frequently in the ponds. Bufotes viridis and long larval period species Pelobates fuscus and Hyla orientalis oviposited almost exclusively in fishless pools. Fish-cue pools were avoided by all species. Anuran richness was higher in fishless pools than in permanent ponds. Species distribution between the two habitats was nested, with both common and rare species occurring in fishless pools.
4. The results indicate the primacy of offspring predation risk over hydroperiod constraints in oviposition decision-making by fish-intolerant anurans. The absence of some species from ponds and pools with fish or fish cues shows that non-consumptive interactions may better explain the scarcity of anuran larvae in waters dominated by fish than actual consumption. The strict avoidance of fish habitats despite their proximity to fishless patches indicates fine-scale assessment of predation risk. However, rigid habitat selection against fish predation on offspring may prove maladaptive if habitats with high desiccation risk are the main alternative and are indiscriminately preferred. Maintenance of fishless wetlands with a hydroperiod sufficient to allow completion of metamorphosis should be a conservation priority for anuran diversity in areas where fishless habitats are limited.