Evolutionary correlations between microhabitat specialisation and locomotor capabilities in the lizard genus Niveoscincus

2007 ◽  
Vol 55 (6) ◽  
pp. 351 ◽  
Author(s):  
Jane Melville
Keyword(s):  
Limited Range ◽  
Convincing Evidence ◽  
Central Issue ◽  
Generalist Species ◽  
Comparative Analyses ◽  
Organismal Biology ◽  
Functional Capabilities ◽  
Habitat Specialists ◽  
Specialist Species ◽  
Evolutionary Consequences

The evolutionary consequences of generalised versus specialised habit is a central issue in organismal biology. Theory predicts that specialist species may have greater capabilities than generalist species in particular habitats but will not be able to maintain this excellence across a broad range of habitats. The evolutionary consequences of ecological specialisation, in terms of functional capabilities, were investigated in the lizard genus Niveoscincus from Tasmania. Breadth of microhabitat occupation and ecologically relevant locomotor capabilities were quantified across the genus. Laboratory performance trials demonstrated that some species excelled in just a few of the five performance traits measured, while other species performed well at all traits but did not excel at any. Results of comparative analyses demonstrate that there is a significant evolutionary correlation between microhabitat breadth and range of locomotor capabilities. These results provide convincing evidence that habitat specialists have a correspondingly limited range of locomotor capabilities.

Habitat generalists drive nestedness in a tropical mountaintop insect metacommunity

2020 ◽  
Author(s):  
Frederico de Siqueira Neves ◽  
Pedro Giovâni da Silva ◽  
Ricardo Solar ◽  
Cássio Alencar Nunes ◽  
Marina do Vale Beirão ◽  
...  
Keyword(s):  
Habitat Specialization ◽  
Ecosystem Functions ◽  
Campo Rupestre ◽  
Species Sorting ◽  
Generalist Species ◽  
Habitat Specialists ◽  
Contrasting Habitats ◽  
Specialist Species ◽  
Underlying Mechanisms ◽  
Habitat Generalists

Abstract Nestedness is widely observed in natural metacommunities, but its underlying mechanisms are still poorly understood. The distribution of habitats in the landscape and differences in dispersal rates of distinct insect taxa can determine the nestedness of the metacommunity. Here, we evaluated how species habitat specialization contributes to metacommunity nestedness in insect groups with different dispersal capacities in a mountaintop landscape in south-eastern Brazil. We sampled ants, butterflies and dung beetles in two main habitats, naturally fragmented forest islands and a grassland matrix (campo rupestre), during both dry and rainy seasons. We classified species according to their degree of habitat specialization (generalists or specialists) based on the relative frequencies and abundances between these two contrasting habitats. Forty of 211 species were classified as habitat specialists, seven as habitat generalists. It was not possible to classify the remaining species. The metacommunity was nested in structure, with habitat generalist species contributing more to nestedness than habitat specialists. Nonetheless, habitat distribution in the landscape did not affect the nestedness of the metacommunity. Our findings reveal that species sorting (for habitat specialists) and mass effects (for habitat generalists) are concurrent processes in the mountaintop forest–grassland mosaic. Our study helps to advance our understanding of the differences in the distribution of generalist and specialist species in a tropical mountaintop landscape and improves our ability to predict and manage the increasingly adverse effects of changes in land use and climate on metacommunities and ecosystem functions.

scholarly journals List of Odonates from the Floresta Nacional de São Francisco de Paula (FLONA - SFP), with two new distribution records for Rio Grande do Sul, Brazil

2016 ◽  
Vol 16 (3) ◽  
Author(s):  
Samuel Renner ◽  
Eduardo Périco ◽  
Göran Sahlén
Keyword(s):  
Rio Grande ◽  
Rio Grande Do Sul ◽  
Generalist Species ◽  
Small Streams ◽  
Specialist Species ◽  
Ombrophilous Forest ◽  
First Time ◽  
Pristine Forest ◽  
New Distribution ◽  
Open Fields

Abstract A survey of Odonata was carried out in the National Forest FLONA - SFP, Northeastern region of the Rio Grande do Sul state, Brazil. This conservation unit is mainly covered by Mixed Ombrophilous Forest (MOF), a subtype of Atlantic Forest biome, being also areas covered in planted Pinus, planted Araucaria and open fields. Our sampling efforts were conducted in thirty aquatic environments inside this reserve during the period between January 2014 and November 2014. The sampling sites were selected randomly, comprehending lakes, bogs, small streams and river sections, all inserted in the four vegetation types occurring in the reserve. Fortysix species of Odonata were collected and grouped into 23 genera and seven families. The dominant families were Coenagrionidae (32%), Libellulidae (32%), Aeshnidae (12%), and, Calopterygidae and Lestidae (9%). As expected, the findings revealed the presence of a highly diverse Odonate assemblage, mainly represented by generalist species in the most human disturbed sectors (Pinus and Open fields) and some specialist species in the pristine forest. Two species were registered for the first time in the state of Rio Grande do Sul, Brazil: Libellula herculea Karsch, 1889 (Libellulidae) and Heteragrion luizfelipei Machado, 2006 (Heteragrionidae).

Reproductive success of wind, generalist, and specialist pollinated plant species following wildfire in desert landscapes

2017 ◽  
Vol 26 (12) ◽  
pp. 1030 ◽  
Author(s):  
Andrew H. Lybbert ◽  
Justin Taylor ◽  
Alysa DeFranco ◽  
Samuel B. St Clair
Keyword(s):  
Reproductive Success ◽  
Plant Species ◽  
Mojave Desert ◽  
Fruit Production ◽  
Native Plant ◽  
Pollination Services ◽  
Generalist Species ◽  
Plant Reproductive Success ◽  
Show Evidence ◽  
Specialist Species

Wildfire can drastically affect plant sexual reproductive success in plant–pollinator systems. We assessed plant reproductive success of wind, generalist and specialist pollinated plant species along paired unburned, burned-edge and burned-interior locations of large wildfires in the Mojave Desert. Flower production of wind and generalist pollinated plants was greater in burned landscapes than adjacent unburned areas, whereas specialist species responses were more neutral. Fruit production of generalist species was greater in burned landscapes than in unburned areas, whereas fruit production of wind- and specialist-pollinated species showed no difference in burned and unburned landscapes. Plants surviving in wildfire-disturbed landscapes did not show evidence of pollination failure, as measured by fruit set and seed:ovule ratios. Generalist- and specialist-plant species established in the interior of burned landscapes showed no difference in fruit production than plants established on burned edges suggesting that pollination services are conserved with increasing distance from fire boundaries in burned desert landscapes. Stimulation of plant reproduction in burned environments due to competition release may contribute to the maintenance of pollinator services and re-establishment of the native plant community in post-fire desert environments.

scholarly journals Mutation load dynamics during environmentally-driven range shifts

2018 ◽  
Author(s):  
Kimberly J. Gilbert ◽  
Stephan Peischl ◽  
Laurent Excoffier
Keyword(s):  
Environmental Change ◽  
Geographic Distance ◽  
Species Range ◽  
Range Shifts ◽  
Strong Impact ◽  
Generalist Species ◽  
Deleterious Alleles ◽  
Species Survival ◽  
Specialist Species ◽  
The Impact

AbstractThe fitness of spatially expanding species has been shown to decrease over time and space, but specialist species tracking their changing environment and shifting their range accordingly have been little studied. We use individual-based simulations and analytical modeling to compare the impact of range expansions and range shifts on genetic diversity and fitness loss, as well as the ability to recover fitness after either a shift or expansion. We find that the speed of a shift has a strong impact on fitness evolution. Fastest shifts show the strongest fitness loss per generation, but intermediate shift speeds lead to the strongest fitness loss per geographic distance. Range shifting species lose fitness more slowly through time than expanding species, however, their fitness compared at equivalent geographic distances spread can be considerably lower. These counter-intuitive results arise from the combination of time over which selection acts and mutations enter the system. Range shifts also exhibit reduced fitness recovery after a geographic shift and may result in extinction, whereas range expansions can persist from the core of the species range. The complexity of range expansions and range shifts highlights the potential for severe consequences of environmental change on species survival.Author SummaryAs environments change through time across the globe, species must adapt or relocate to survive. Specialized species must track the specific moving environments to which they are adapted, as compared to generalists which can spread widely. During colonization of new habitat, individuals can accumulate deleterious alleles through repeated bottlenecks. We show through simulation and analytic modeling that the process by which these alleles accumulate changes depending upon the speed at which populations spread over a landscape. This is due to the increased efficacy of selection against deleterious variants at slow speeds of range shifts and decreased input of mutations at faster speeds of range shifts. Under some selective circumstances, shifting of a species range leads to extinction of the entire population. This suggests that the rate of environmental change across the globe will play a large role in the survival of specialist species as compared to more generalist species.

scholarly journals Role of physiological monitoring in educational organizations

2019 ◽  
Vol 72 ◽  
pp. 03005
Author(s):  
Olga Shchkvirina ◽  
Dinamutdin Misirov ◽  
Marina Akopyan ◽  
Irina Loseva
Keyword(s):  
Heart Rate ◽  
Heart Rate Variability ◽  
Functional State ◽  
Initial Period ◽  
Educational Environment ◽  
Convincing Evidence ◽  
Educational Process ◽  
The Body ◽  
Objective Criterion ◽  
Functional Capabilities

An indicators analysis of the first-graders functional state and vegetative homeostasis obtained in the initial period of adaptation to the educational environment revealed gender differences in the rates of the adaptation process to new learning conditions. It has been established that girls’ adaptation mechanisms turn on earlier than boys’, with their similar orientation. The article provides an experimental justification of the indicators use legitimacy for heart rate variability to assess the functional state of the body in the acute period of adaptation to the educational environment. The importance of teacher physiological literacy for the optimization of the educational process is substantiated. The results of the study are convincing evidence of the knowledge importance for the physiological foundations of the occurrence and course of physiological and mental processes, stable individual psycho-physiological characteristics for the organization of the learning environment, corresponding to the functional capabilities of the body. This argument is also confirmed by many years of experience among master students key competencies development, which allow using such an objective criterion as the current functional state of the body to ensure, through the joint efforts of parents, teachers, psychologists, and doctors, the correction of the educational environment and psycho-physiological resistance of individual to it. The established differences in the dynamics of heart rate variability indicators for girls and boys can be used to form a health-saving program in school settings.

scholarly journals Community structure of metazoan parasites of silverside, Odontesthes bonariensis (Pisces, Atherinopsidae) from Argentina

2012 ◽  
Vol 102 (1) ◽  
pp. 26-32 ◽  
Author(s):  
Fabiana B. Drago
Keyword(s):  
Parasite Species ◽  
Host Record ◽  
Component Community ◽  
New Host ◽  
Metazoan Parasites ◽  
Generalist Species ◽  
New Host Record ◽  
Host Sex ◽  
Odontesthes Bonariensis ◽  
Specialist Species

The helminth communities of silverside, Odontesthes bonariensis (Valenciennes, 1835), from two Argentinean lagoons were studied and compared at component community and infracommunity levels. Nine helminth species were found: five digeneans (Austrodiplostomum cf. mordax, Ascocotyle (Phagicola) cf. diminuta, Ascocotyle sp., Thometrema bonariensis and Saccocoelioides sp.); two nematodes (Contracaecum sp. and Hysterothylacium sp.); one acanthocephalan (Wolffhugelia matercula) and one cestode (Cangatiella macdonaghi). Odontesthes bonariensis is a new host record for five parasite species. Richness, diversity and number of helminths in silversides from Salada Grande lagoon were higher than in those from Lacombe lagoon. This could be related with lagoon size, abundance of mollusks and fish-eating birds, and size and diet of silversides captured in each lagoon. In Salada Grande lagoon the helminth community of silversides was dominated by the allogenic and generalist species A. cf. mordax; while the autogenic and intermediate specialist species C. macdonaghi was dominant in Lacombe lagoon. Host sex did not affect richness, diversity or total abundance, whereas host size was positively correlated with these attributes, except diversity in Salada Grande lagoon.

Co-occurring Notonecta (Hemiptera: Heteroptera: Notonectidae) Species Differ in Their Behavioral Response to Cues of Belostoma (Hemiptera: Heteroptera: Belostomatidae) Predation Risk

2019 ◽  
Vol 112 (4) ◽  
pp. 402-408
Author(s):  
Ilia Maria C Ferzoco ◽  
Celina B Baines ◽  
Shannon J McCauley
Keyword(s):  
Predation Risk ◽  
Chemical Cues ◽  
Habitat Specialization ◽  
Life History Strategies ◽  
Generalist Species ◽  
Ephemeral Ponds ◽  
Trade Offs ◽  
Specialist Species ◽  
Species Specific ◽  
Shared Predator

Abstract Predators affect prey through direct consumption as well as by inducing prey to defensively alter their phenotypes, including behavioral phenotypes, to maximize survival under predation risk. Closely related sympatric prey species with shared natural enemies may resolve behavioral trade-offs under predation risk differently. In a laboratory experiment, we investigated two co-occurring semiaquatic backswimmer congeners, which exhibit differences in their degree of habitat specialization across a gradient of habitat permanence. Notonecta irrorata Uhler primarily occur in ephemeral ponds, whereas Notonecta undulata Say are habitat generalists that are commonly found in both permanent and ephemeral ponds. We tested whether the two species differed in antipredator responses to both visual and chemical cues of a shared predator, the giant water bug, in a fully factorial design. The generalist species, N. undulata, exhibited reductions in activity in the presence of predator chemical cues only, whereas the specialist species, N. irrorata, remained consistently active across predator cue treatments. Our work shows that there are species-specific differences in how prey assess or respond to predation risk. The varying propensities of these backswimmer congeners to behaviorally respond to a shared predator, and differences in their behavior when exposed to different predation risk cues may be linked to underlying divergence in their life-history strategies.

scholarly journals Loss of Generalist Plant Species and Functional Diversity Decreases the Robustness of a Seed Dispersal Network

2018 ◽  
Vol 46 (1) ◽  
pp. 52-58 ◽  
Author(s):  
Vinicius AG Bastazini ◽  
Vanderlei J Debastiani ◽  
Bethânia O Azambuja ◽  
Paulo R Guimarães ◽  
Valério D Pillar
Keyword(s):  
Seed Dispersal ◽  
Plant Species ◽  
Functional Diversity ◽  
Woody Plant ◽  
Simulation Studies ◽  
Biological Factors ◽  
Generalist Species ◽  
Cascading Effects ◽  
Forest Mosaic ◽  
Specialist Species

SummaryUnderstanding cascading effects of species loss is a major challenge for ecologists. Traditionally, the robustness of ecological networks has been evaluated based on simulation studies where primary extinctions occur at random or as a function of species specialization, ignoring other important biological factors. Here, we estimate the robustness of a seed dispersal network from a grassland–forest mosaic in southern Brazil, simulating distinct scenarios of woody plant species extinction, including scenarios where species are eliminated based on their evolutionary and functional distinctiveness. Our results suggest that the network is more robust when species are eliminated based on their evolutionary uniqueness, followed by random extinctions, the extinction of the most specialist species, functional distinctiveness and, at last, when the most generalist species are sequentially eliminated. Our results provide important information for grassland–forest mosaic management, as they indicate that loss of generalist species and functional diversity makes the system more likely to collapse.

Age-dependent colonization of urban habitats: a diachronic approach using carabid beetles and spiders

2013 ◽  
Vol 63 (3) ◽  
pp. 257-269 ◽  
Author(s):  
Marion Varet ◽  
Françoise Burel ◽  
Denis Lafage ◽  
Julien Pétillon
Keyword(s):  
Urban Areas ◽  
Time Lag ◽  
Ecosystem Dynamics ◽  
Carabid Beetles ◽  
Life History Trait ◽  
Generalist Species ◽  
High Dispersal ◽  
Specialist Species ◽  
Habitat Generalist ◽  
Habitat Specialist Species

Urbanization creates human disturbance that plays an important role in ecosystem dynamics. Most of the time, there is a time lag between disturbance and colonization. Opportunistic species with high dispersal power colonize first, while habitat specialist species with a lower power of dispersal colonize later; the communities change with time after disturbance. We hypothesize that, following the establishment of a new neighbourhood, arthropod communities will change from habitat generalists to specialists, and will be more similar to those of the adjacent countryside. We selected two groups of invertebrates often used as bioindicators, spiders and carabid beetles. The following parameters were estimated: assemblage composition, species richness, activity-density total and per life history trait (broad habitat preference). The field data were collected in 2010 within 3 towns located in France. Neighbourhoods of 10 and 30 years old were pair-matched in these towns and sampled using pitfall traps set randomly in hedgerows (120 traps in total). 2101 adult spiders belonging to 89 species were collected, whereas the 643 captured carabid beetles belonged to 24 species. We found no evidence of any significant change in carabid beetle and spider communities according to neighbourhood age. The assemblages were mainly composed of habitat generalist species. These results suggest that urban areas can be seen to be in continual state of disruption, and colonization of these areas is assumed to be relatively rapid (i.e., less than 10 years in our case study), although incomplete.

scholarly journals Increasing connectivity enhances habitat specialists but simplifies plant–insect food webs

Oecologia ◽  
2020 ◽  
Author(s):  
Péter Batáry ◽  
Verena Rösch ◽  
Carsten F. Dormann ◽  
Teja Tscharntke
Keyword(s):  
Food Webs ◽  
Landscape Connectivity ◽  
Arable Land ◽  
Calcareous Grassland ◽  
Landscape Matrix ◽  
Generalist Species ◽  
Habitat Specialisation ◽  
Habitat Specialists ◽  
Surrounding Landscape ◽  
Complex Landscapes

AbstractStrong declines of grassland species diversity in small and isolated grassland patches have been observed at local and landscape scales. Here, we study how plant–herbivore interaction webs and habitat specialisation of leafhopper communities change with the size of calcareous grassland fragments and landscape connectivity. We surveyed leafhoppers and plants on 14 small (0.1–0.6 ha) and 14 large (1.2–8.8 ha) semi-natural calcareous grassland fragments in Central Germany, differing in isolation from other calcareous grasslands and in the percentage of arable land in the surrounding landscape (from simple to complex landscapes). We quantified weighted trophic links between plants and their phytophagous leafhoppers for each grassland fragment. We found that large and well-connected grassland fragments harboured a high portion of specialist leafhopper species, which in turn yielded low interaction diversity and simple plant-leafhopper food webs. In contrast, small and well-connected fragments exhibited high levels of generalism, leading to higher interaction diversity. In conclusion, food web complexity appeared to be a poor indicator for the management of insect diversity, as it is driven by specialist species, which require high connectivity of large fragments in complex landscapes. We conclude that habitat specialists should be prioritized since generalist species associated with small fragments are also widespread in the surrounding landscape matrix.

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