Lithopanspermia is defined as dispersal of living extremophiles from one planetary body to another, through life-bearing rocks ejected by meteor impacts. If lithopanspermia proves concrete, it should ...be viewed as an eco-evolutionary phenomenon. Biogeographic/microevolutionary models have been proposed as analogues for lithopanspermia dynamics; however, extremophile arrival on a planetary body is not the end of story. Here, we suggest that eco-evolutionary (environment + organismal microevolution) dynamics can lead to distinct macroevolutionary scenarios after extremophile arrival on a planetary body. Speciation would be the most important factor in interplanetary dynamics due to the possibly long time and distance between dispersive events, similar to long-distance dispersal dynamics on Earth. In previously uninhabited planets, persistence of extremophiles and descendants depends almost only on evolvability of extremophiles against abiotic filters. Considering a previously inhabited planet, ecological interactions at local or global scales could drive persistence (speciation/extinction) of extremophiles in the new habitat. Thus, we might expect high extinction rates if negative interactions are dominant, or, high speciation, if positive interactions occur, with extremophile lineages overpower (or not) the native biota. If interplanetary dispersal is possible, theories about the evolution of life may be universal, leading to a general eco-evolutionary model for life in the Universe.
Fire is a frequent disturbance in most grasslands around the world, being key for the structure and dynamics of the biodiversity in such ecosystems. While grassland species may be resilient, little ...is known on how plant–pollinator networks reassemble after fire. Here, we investigate the structure and dynamics of plant–pollinator networks and the variation in species roles over a 2-year post-fire chronosequence on grassland communities in Southern Brazil. We found that both network specialization and modularity were similar over the chronosequence of time-since-fire, but in freshly burnt areas, there were more species acting as network hubs. Species roles exhibited high variation, with plant and pollinator species shifting roles along the post-disturbance chronosequence. Interaction dissimilarity was remarkably high in networks irrespective of times-since-fire. Interaction dissimilarity was associated more with rewiring than with species turnover, indicating that grassland plant and pollinator species are highly capable of switching partners. Time-since-fire had little influence on network structure but influenced the identity and diversity of pollinators playing key roles in the networks. These findings suggest that pollination networks in naturally fire-prone ecosystems are highly dynamic and resilient to fire with both plants and pollinators being highly capable of adjusting their interactions and network structure after disturbance.
Understanding biological community distribution patterns and their drivers across different scales is one of the major goals of community ecology in a rapidly changing world. Considering natural ...forest-grassland ecotones distributed over the south Brazilian region we investigated how ant communities are assembled locally, i.e. considering different habitats, and regionally, i.e. considering different physiographic regions. We used taxonomic and phylogenetic approaches to investigate diversity patterns and search for environmental/spatial drivers at each scale. We sampled ants using honey and tuna baits in forest and grassland habitats, in ecotones distributed at nine sites in Rio Grande do Sul state, Brazil. Overall, we found 85 ant species belonging to 23 genera and six subfamilies. At the local scale, we found forests and grasslands as equivalent in ant species and evolutionary history diversities, but considerably different in terms of species composition. In forests, the soil surface air temperature predicts foraging ant diversity. In grasslands, while the height of herbaceous vegetation reduces ant diversity, treelet density from forest expansion processes clearly increases it. At a regional scale, we did not find models that sufficiently explained ant taxonomic and phylogenetic diversity based on regional environmental variables. The variance in species composition, but not in evolutionary histories, across physiographic regions is driven by space and historical processes. Our findings unveil important aspects of ant community ecology in natural transition systems, indicating environmental filtering as an important process structuring the communities at the local scale, but mostly spatial processes acting at the regional scale.
Abstract
Ecological networks describe community structure by focusing on how nodes are connected by links (interactions). Related species have higher probabilities of sharing links if interactions ...depending on phylogeny and/or species are functionally similar; however, if and how this modularity impacts higher trophic levels is still an open question.
We aimed to evaluate the effect of different structuring factors on an observed bipartite network of galling insects and associated parasitoids on a system with two closely related and recently diverged plants, where host‐tracking could be underway. We hypothesized that gall structure, galler taxonomy and host plant identity could contribute, from a higher to a lower degree respectively, to network modularity by generating a selective pressure on parasitoids.
Samples were collected between May 2015 and June 2017 in the forest areas of Porto Alegre, southern Brazil. Overall, we found 4629 galls of three monophagous and four oligophagous galling species; 664 parasitoid individuals were obtained and classified into 37 morphospecies.
We constructed four networks with the collected data by organising nodes according to the tested factors, that is, gall structure, galler taxonomy, host plant identity and gall–plant interaction. All networks were significantly modular, and for three out of four analysed factors (gall structure, galler taxonomy and gall–plant interaction), modularity levels were at least intermediate (at about
Q
= 0.4).
Barriers to or preferences for certain interactions appear to be responses to multiple concomitant factors. However, galler taxonomy and host plant identity are somehow stronger determinants for the parasitoids in terms of attacked hosts.
ABSTRACT Bruggmannia capixaba, sp. n., Bruggmannia gaucha, sp. n., and Bruggmannia marambaiensis sp. n. are described and illustrated. All species were collected in Atlantic forest areas. They induce ...galls on Guapira (Nyctaginaceae), a plant genus native to Brazil, the first on G. pernambucensis and the others on G. opposita. Furthermore, the male and larva of Bruggmannia monteiroi are described for the first time, based on specimens collected in the type locality.
Butterflies are among the most colourful organisms in the world and colour plays a central role in many of their life-history strategies. However, the efficacy of coloration strategies in these and ...other animals could be affected by sudden environmental changes, including anthropogenic disturbances such as habitat loss and fragmentation. Here we investigate the effect of forest disturbance gradients on the colours of fruit-feeding butterflies in the Amazon Rainforest. The disturbance gradients tested represented habitat-size (continuous primary forests versus forest fragments of 1, 10 and 100 ha) and succession gradients (continuous primary forests, 30 year old secondary forests, and three year old early successional forests). Using digital image analysis, we obtained intrinsic measures of butterfly colour patches corresponding to hue, saturation, brightness, in addition to measures of the contrast among patches and of the overall wing-colour diversity corresponding to 220 individuals, belonging to 60 species. Our results showed that butterflies in the secondary forest and continuous primary forest are more colourful than those found in early succession and fragments of forests. Individuals occurring in forests of early succession showed higher average values of hue and saturation, but lower brightness. Accompanying changes in colour composition, wing-colour diversity among species was lower in human-disturbed habitats, such as those of early forest succession and secondary forest. Forest fragments have smaller effects on butterfly colour composition, indicating that well-structured forest habitats can house butterfly assemblages with more diverse phenotypic features and colours. We show how high deforestation rates in recent years is linked with negative changes in functional coloration strategies (e.g. camouflage, warning colours), something that has to date been poorly explored or demonstrated for butterflies. Specifically, human interference has apparently placed butterflies under strong selection for lower diversity in their colours and range of defensive strategies. Those species that are most colourful are the first to be locally extinguished, likely due to removal of native vegetation and increased exposure to predators, and more broadly owing to inhospitable environmental conditions. This illustrates an accelerated loss of local fauna and a “discolouration” of the Amazonian butterflies due to anthropogenic impacts.
Environmental gradients consist of sequential changes in the physical and structural characteristics of a region. These allow us to follow species responses and tolerances under different habitat ...conditions. Among them, forest fragmentation and succession comprise the most common examples of forest gradients, where organismal responses require distinct morphological, physiological, and behavioral adaptations. However, environmental changes can impose ecological and evolutionary constraints that act on species traits, as well as on local species assemblies through their phylogenetic history. In this study, we evaluated the differences in species distribution and composition on fruit‐feeding butterfly assemblages along forest fragmentation and succession gradients. We combine functional and phylogenetic methods for determining butterfly assemblages, and inferred species resistance and resilience according to habitat changes in tropical forests. We used a database of 471 fruit‐feeding butterflies of 60 species sampled from different environments in the central Amazon rainforest. A total of 13 functional traits were measured, and a phylogenetic tree was obtained for the sampled species. The trait–environment relationship was analyzed along both forest fragmentation and succession gradients, controlling for phylogenetic signal on species distribution and functional composition when necessary. Several traits presented phylogenetic signal, and phylogeny was also driving butterfly species distribution along the successional gradient. After controlling for phylogeny, individual characteristics related to flight speed (thoracic weight) and anti‐predatory strategies (camouflage) increased in early‐successional forests, with large butterflies (body length) prevailing in primary forests. No clear functional and phylogenetic pattern was identified for the fragmentation gradient. Our results are consistent with the idea that butterflies may be employing distinct functional strategies to attenuate habitat change effects. Larger butterflies, with lower dispersal ability, are preferentially susceptible to local extinctions in the early‐successional environments, mainly when forested habitat and its resources become spatially restricted. In addition, several anti‐predatory strategies related to conspicuous colors may be losing their functionality in open areas, where not being distinctive against the background becomes the primary defense against predation.
Disturbances are primary forces creating spatial heterogeneity in ecosystems, and inducing changes on biological communities, abiotic characteristics and ecological processes. Here we focus on the ...effects of fire disturbance in the decomposition process at subtropical Campos grasslands in South Brazil, where burns are traditionally used to reduce shrub encroachment, and improve forage quality. We experimentally investigated how burns and the changes they produce in grassland habitat conditions affect soil fauna detritivory and surface leaf‐litter decaying patterns over one year. Previously to fire, we found significant correlation of litter decay with plant evenness and detritivory rates in non‐disturbed grasslands. One month after fire grassland patches presented reduced soil fauna densities and surface feeding activity possible because of the mortality caused directly by heating, and/or due to harsh microenvironmental filters to fauna colonization and permanency (e.g. decreased humidity). At 6–7 months after fire however these features did not differ any more from the paired unburned plots. On the other hand, canopy openness accelerated the decaying of leaf‐litter in burned patches by allowing increased action of abiotic factors as solar radiation potentially triggering photodegradation. These effects seemed to last less than one year. Overall, our results bring insights regarding drivers of soil ecological processes at local scales in subtropical grasslands, and suggest that detritivory and litter decay processes are sensitive to fire, but resilient following grassland recovering.
Grasslands are historically and evolutionarily associated with disturbances, such as fire, that drive biodiversity assembly patterns and biotic interactions. Disturbance suppression in fire‐prone ...ecosystems usually leads to a decline in forb diversity and flowering due to biomass accumulation, which could jeopardise pollinator diversity. In this study, we investigated patterns and drivers of plant flowering and flower insect visitor communities in a chronosequence of patches from different time‐since‐fire categories in Southern Brazilian grasslands. Old‐burnt patches (more than 2 years since fire) had taller vegetation, more biomass and grass cover than intermediate (about 1 year after fire) and freshly‐burnt patches (less than 6 months since fire), which had increased bare soil cover. Forb flower abundance was much higher in freshly burnt patches, directly predicted by the degree of habitat openness. Pollinator insects were then benefited by floral resource aggregation in freshly burnt patches, increasing in abundance (bees and butterflies) and species richness (bees). Beetle communities were positively influenced by vegetation height. Furthermore, plant species flowering and bee species composition varied between freshly and old‐burnt grasslands, with indicator species found for all recovery stages but mainly freshly‐burnt patches. Altogether, these results indicate the importance of maintaining freshly‐burnt patches in the grassland landscape: it helps to sustain flower diversity, pollination services and flowering plant reproduction. Our findings support the idea that a mosaic of grasslands from different times‐since‐fire should be considered for grassland conservation.
We investigated patterns and drivers of plant flowering and flower insect visitor communities in a chronosequence of patches from three different time‐since‐fire categories in Southern Brazilian grasslands. Pollinator insects were benefited by floral resource aggregation in freshly‐burnt (FB) patches, increasing in abundance (bees and butterflies) and species richness (bees). Furthermore, plant species flowering and bee species composition varied between FB and old‐burnt (OB), but did not differ from intermediate‐burnt (IB) grasslands. Altogether, these results indicate the importance FB patches to sustain pollination services, and support that a mosaic of grasslands from different times‐since‐fire should be considered for grassland conservation.
Including ecosystem functions into restoration ecology has been repeatedly suggested, yet there is limited evidence that this is taking place without bias to certain habitats, species, or functions. ...We reviewed the inclusion of ecosystem functions in restoration and potential relations to habitats and species by extracting 224 publications from the literature (2004–2013). Most studies investigated forests, fewer grasslands or freshwaters, and fewest wetlands or marine habitats. Of all studies, 14% analyzed only ecosystem functions, 44% considered both biotic composition and functions, 42% exclusively studied the biotic component, mostly vascular plants, more rarely invertebrates or vertebrates, and least often microbes. Most studies investigating ecosystem functions focused on nutrient cycling (26%), whereas productivity (18%), water relations (16%), and geomorphological processes (14%) were less covered; carbon sequestration (10%), decomposition (6%), and trophic interactions (6%) were rarely studied. Monitoring of ecosystem functions was common in forests and grasslands, but the functions considered depended on the study organisms. These associations indicate research opportunities for certain habitats, species, and functions. Overall, the call to include ecosystem functions in restoration has been heard; however, a lack of clarity about the ecosystem functions to be included and deficits of feasible field methods are major obstacles for a functional approach. Restoration ecology should learn from recent advances in rapid assessment of ecosystem functions, and by a closer integration with biodiversity–ecosystem functioning research. Not all functions need to be measured in all ecosystems, but more functions than the few commonly addressed would improve the understanding of restored ecosystems.
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