La Naturaleza de las Especies de Frailejones: Un Experimento de Jardín Común en Sumapaz

Combining common garden experiments with reciprocal transplant or sowing experiments is widely used to assess local adaptation in plants. This approach effectively minimizes the potential influence of maternal environments derived from seed origin. However, the impact of divergent common garden environments on local adaptation assessment has received limited attention in previous studies. To investigate the effects of diverse common garden conditions on the assessment of local adaptation, we conducted a 2‐year common garden experiment followed by a 5‐year reciprocal sowing experiment, both carried out at two different elevations. Seeds from low‐ and high‐elevation populations of Elymus nutans were directly sown in the common garden experiment to propagate seeds for the subsequent reciprocal sowing experiment. Multiple traits, including seedling emergence, survival, plant height, above‐ground biomass, number of reproductive branches, and the number of seeds per individual, were measured in both experiments. This comprehensive method allowed us to examine variations in local adaptation across different growth age and life cycle stages. The original low‐elevation population consistently outperformed the foreign population at the low‐elevation site, regardless of whether seeds were propagated in low or high‐elevation common gardens, indicating clear local adaptation. In contrast, the original high‐elevation population showed local adaptation only when seeds were propagated in the low‐elevation common garden. Long‐term experiments revealed a gradual decline in the strength of local adaptation in E. nutans over the years. Local adaptation was most evident in the number of seeds, with smaller advantages observed in seedling survival and a number of reproductive branches. No evidence of local adaptation was detected in other traits. Synthesis. The local adaptation of Elymus nutans was primarily observed during early growth age since seeding and was highly dependent on the common garden conditions in which the seeds were propagated. Therefore, it is crucial to carefully consider common garden conditions when evaluating plant local adaptation through common garden and reciprocal transplant experiments.

Background: The identification of genetic divergence among provenances is essential for designing seed zones for ecological restoration, but this is neither easy nor cheap, especially where tropical trees are concerned.Aims: In this study we sought to investigate the effectiveness of common garden and short-term reciprocal transplant experiments to identify genetic divergence in populations of Queen palm (Syagrus romanzoffiana).Methods: Seed harvesting was carried out in south-eastern Brazil, in natural remnants of seasonally dry forest, restinga and cerradão. Under common garden conditions, we examined the length of the cotyledonary petiole of three-month-old seedlings, and important sapling traits of 10-month-old nursery-grown individuals of the three above-mentioned seed provenances. Additionally, reciprocal transplants were carried out during 10 months for seasonally dry forest and cerradão seed lots.Results: In the common garden experiments, restinga seedlings had significantly shorter cotyledonary petioles, and cerradão saplings showed ca. 40% higher values for root, leaf blade, shoot and total dry mass, while saplings did not express genetic differences in reciprocal transplants, which is one of the four possible combined outcomes discussed here.Conclusions: Common garden experiments with long-lived tropical plant species used in ecological restoration can be advantageously used to improve the quality of the seed sources for restoration projects by detecting genetic divergence with a possible relation to local adaptation.

In the present study, stratigraphic data from cores and outcrop sections are integrated with data on thermal maturity, organic facies, and thermochronometric information to reconstruct the tectonic and associated petroleum system evolution of the eastern foothills thrust belt along the Colombian Eastern Cordillera, one of the most prolific hydrocarbon provinces in northern South America. Sedimentary and tectonic burial of the foreland autochthon caused maturation of the Coniacian to Santonian shallow marine Chipaque Formation, resulting in successive and diachronous episodes of hydrocarbon migration and trapping. One-dimensional and two-dimensional maturation modeling indicates that oil generation from the Chipaque Formation began at the Paleocene-Eocene boundary (55 Ma) in the southern parts of what is now the Eastern Cordillera and progressed to the north. By the late Oligocene, tectonic inversion of the Eastern Cordillera exhumed most of these kitchens, terminating the oil generation from the Chipaque Formation. Kitchens migrated northward and eastward during the Oligocene and early Miocene. Because of the absence or subsequent erosion of traps, it is likely that the southernmost source rocks expelled most of their oil without any appreciable accumulation. Our modeling indicates that there were two important kitchens during the Cenozoic. The larger of the two was located in the present-day Eastern Cordillera, and it was most productive in the late Eocene–early Oligocene. The second kitchen, which generated oil throughout the Neogene, was located in the foredeep of the Llanos basin, adjacent to the mountain front. Considerable amounts of oil from this recent pulse have accumulated in both deep and shallow reservoirs along the eastern foothills. The modeled reservoir charge history also explains the substantial biodegradation of oils in reservoirs that are today much too deep to support the process. Biodegradation must have occurred when the reservoirs were shallower and at cooler temperatures, and they remained active until the reservoirs were buried to depths where temperatures were high enough to prevent further bacterial activity.

Species delimitation in recent radiations is challenging because these species often display overlap in their expression of morphological characters. Here we analyze morphological characters measured from field-collected herbarium specimens and compare them to measurements from live plants grown in a common garden to determine reliable characters that could be used to delimit species in the Myosotis pygmaea (Boraginaceae) species group in New Zealand. This species complex is of primary interest because it includes many threatened species as well as several taxonomically indeterminate entities. The common garden experiment revealed high levels of morphological plasticity within the M. pygmaea species group, as plants in the common garden grew to be strikingly larger than those in the field. The M. pygmaea species complex was found to be a morphologically definable group, and several taxonomically indeterminate entities were placed as being either morphologically similar to the M. pygmaea species group or to other species complexes. In multidimensional scaling analyses of morphological data, of the five named species that make up the M. pygmaea species group, three formed separate clusters (M. pygmaea, M. glauca, and M. brevis), and the two others were indistinguishable from each other (M. antarctica and M. drucei). This study represents an important step towards a planned integrative taxonomic revision of the M. pygmaea species group, and highlights the value of morphological data collected from a common garden experiment.

Phenotypic plasticity is essential for the persistence of organisms under changing environmental conditions but the control of the relevant cellular mechanisms including which genes are involved and the regulation of those genes remains unclear. One way to address this issue is to evaluate links between gene expression, methylation and phenotype using transplantation and common garden experiments within genetically homogeneous populations. This approach was taken using the Antarctic limpet Nacella concinna. In this species, two distinct phenotypes are associated with the intertidal and subtidal zones. The in situ gene expression and methylation profiles of intertidal and subtidal cohorts were directly compared before and after reciprocal transplantation as well as after a common garden acclimation to aquarium conditions for 9 months. Expression profiles showed significant modulation of cellular metabolism to habitat zone with the intertidal profile characterised by transcription modules for antioxidant production, DNA repair and the cytoskeleton reflecting the need to cope with continually fluctuating and stressful conditions including wave action, UV irradiation and desiccation. Transplantation had an effect on gene expression. The subtidal animals transplanted to the intertidal zone modified their gene expression patterns towards that of an intertidal profile. In contrast, many of the antioxidant genes were still differentially expressed in the intertidal animals several weeks after transplantation into the relatively benign subtidal zone. Furthermore, a core of genes involved in antioxidation was still preferentially expressed in intertidal animals at the end of the common garden experiment. Thus, acclimation in an aquarium tank for 9 months did not completely erase the intertidal gene expression profile. Significant methylation differences were measured between intertidal and subtidal animals from the wild and after transplantation, which were reduced on common garden acclimation. This suggests that epigenetic factors play an important role in physiological flexibility associated with environmental niche. A plain language summary is available for this article.

Savanna tree regrowth after defoliation explained by bud activation rather than reserve mobilization

Rethinking the common garden in invasion research

The systematics of Rhabdophis subminiatus (Schlegel, 1837) at subspecies level has long proved to be controversial. We analyse the variation of selected morphological characters in 179 specimens from populations covering the whole range of R. subminiatus sensu lato. Based on this review, we recognize four morphological groups, of which two do not agree with the current definitions and distributions of the currently recognized subspecies R. s. subminiatus. The “northernmost group” agrees with the definition of Natrix helleri Schmidt, 1925. In contrast, the “southernmost group” agrees with the syntypes of Tropidonotus subminiatus and we here restrict this species to the Sunda Region. We also discuss a previous designation of the lectotype of T. subminiatus, which we consider invalid, and we here make it valid in the sense of the Code. Furthermore, our analysis allows us to define a third group that is widespread in the Indochinese Region and Malayan Peninsula. For this geographically “central group”, the name Natrix subminiata siamensis Mell, 1931, is available. We therefore resurrect this taxon from its synonymy with R. subminiatus and we designate a lectotype in agreement with requirements of the Code. Lastly, we recognize a fourth group at species level, endemic to Hainan Island, China, that we describe as a new species. This division into four morphological groups at species level is coherent with phylogenetic analyses recently published in the literature. We also discuss and modify the taxonomic status of Natrix subminiata hongkongensis Mell, 1931 and Natrix (Rhabdophis) laobaoensis Bourret, 1934, now regarded as synonyms of R. subminiatus and R. siamensis, respectively.

The way functional traits affect growth of plant species may be highly context‐specific. We asked which combinations of trait values are advantageous under field conditions in managed grasslands as compared to conditions without competition and land‐use. In a two‐year field experiment, we recorded the performance of 93 species transplanted into German grassland communities differing in land‐use intensity and into a common garden, where species grew unaffected by land‐use under favorable conditions regarding soil, water, and space. The plants’ performance was characterized by two independent dimensions (relative growth rates (RGR) of height and leaf length vs. aboveground biomass and survival) that were differently related to the eight focal key traits in our study (leaf dry matter content (LDMC), specific leaf area (SLA), height, leaf anatomy, leaf persistence, leaf distribution, vegetative reproduction, and physical defense). We applied multivariate procrustes analyses to test for the correspondence of the optimal trait–performance relationships between field and common garden conditions. RGRs were species‐specific and species ranks of RGRs in the field, and the common garden were significantly correlated. Different traits explained the performance in the field and the common garden; for example, leaf anatomy traits explained species performance only in the field, whereas plant height was found to be only important in the common garden. The ability to reproduce vegetatively, having leaves that are summer‐persistent and with high leaf dry matter content (LDMC) were traits of major importance under both settings, albeit the magnitude of their influence differed slightly between the field and the common garden experiment. All optimal models included interactions between traits, pointing out the necessity to analyze traits in combination. The differences between field and common garden clearly demonstrate context dependency of trait‐based growth models, which results in limited transferability of favorable trait combinations between different environmental settings.

Protogyrodactylus ethiopicus sp. n. and P. kritskyi sp. n. are described from the gills of Gerres nigri Günther (Gerreidae, Perciformes) captured from the estuary of the Sine-Saloum River (Senegal, West Africa). These new species differ from previously described species within the genus by a mid- or dextro-ventral vaginal opening (dextral in all other species). They are part of a morphological species group within Protogyrodactylus Johnston et Tiegs, 1922 that has the tip of the superficial root of the ventral anchor resembling a hook and two anterior projections on the anterior margin of the ventral bar. Protogyrodactylus ethiopicus differs from the remaining species in this group mainly by the morphology of the base of the male copulatory organ (MCO), which is disk-shaped, and the shape of the anterior projections of the ventral bar (round in the new species and relatively elongate in the other species of the group). The other new species, P. kritskyi, differs from all others in the same morphological group in having a MCO with a greatly expanded base that bears a heel-like subterminal sclerotization.

This paper and a companion article present illustrated guides to the identification of sub-fossil chironomid larvae (Insecta: Diptera: Chironomidae) preserved in the sediments of low- and mid-elevation lakes in East Africa. They are based on analysis of surface-sediment death assemblages from 61 lakes located in the humid to semi-arid environments of equatorial East Africa (Uganda, Kenya, Tanzania), supplemented with similar surface-sediment samples from 12 lakes in the Horn of Africa (Ethiopia), and sub-recent core samples from six lakes in Kenya and two in Uganda. We analyzed about 11,000 specimens and identified 98.4% of these to species, species group, genus, or tribe level depending on current α -taxonomic knowledge of the various genera considered and the taxonomic resolution of preserved diagnostic features. We distinguished 90 different sub-fossil morphotypes, of which 16 are Tanypodinae, 19 are Orthocladiinae, and 55 are Chironominae. Diagnostic characters distinguishing these morphotypes from each other resemble differences at the species level in the better-known Holarctic fauna, hence we consider most of our morphotypes equivalent to morphological species or groups of closely related species. In this paper we focus on the Tanypodinae and Orthocladiinae, with special attention to the high taxon richness among the Pentaneurini. Patterns of cephalic setation were found to facilitate identification of Tanypodinae both at the genus and species level, and contributed to improved taxonomic resolution in sub-fossil East African material. High taxon richness and numerical abundance of the Orthocladiinae in our study lakes indicates that a considerable number of African Orthocladiinae is adapted to warm standing-water environments.

Molecular systematics of the neotropical scorpion genus Tityus (Buthidae): The historical biogeography and venom antigenic diversity of toxic Venezuelan species

RAPD fragment pattern analysis and morphological segregation of small-spored Alternaria species and species groups

Soil-borne pathogens are posited to maintain forest diversity. However, their in situ impact and spatial variation are largely unknown. We examined spatial patterns of pathogenic activity in a deciduous forest using a common garden experiment and also in a natural experiment around replicated trees, and we quantified Pythium (a soil-borne pathogen) density around individual Prunus serotina trees. In both experiments, P. serotina seedling survival was 52-57% greater in plots treated with a metalaxyl-based fungicide specific to oomycetes (i.e., Pythium) than in untreated plots. Disease dynamics were not density dependent, but pathogenic activity and Pythium density were spatially variable. In the common garden and natural experiments, pathogenic activity of soil inoculum varied among trees, while in the natural experiment disease dynamics were also distance dependent and pathogenic activity decreased away from P. serotina trees. Disease and Pythium density were not always related but displayed considerable spatial variation. We found that Pythium density did not vary with distance away from P. serotina trees but did vary among trees. Understanding the spatial complexity of soil-borne pathogens is critical to accurately characterizing their effects on populations and ultimately on forest diversity.

Experiments using natural populations have provided mixed support for thermal adaptation models, probably because the conditions are often confounded with additional environmental factors like seasonality. The contrasting geothermal environments within Lake Mývatn, northern Iceland, provide a unique opportunity to evaluate thermal adaptation models using closely located natural populations. We conducted laboratory common garden and field reciprocal transplant experiments to investigate how thermal origin influences the life history of Radix balthica snails originating from stable cold (6°C), stable warm (23°C) thermal environments or from areas with seasonal temperature variation. Supporting thermal optimality models, warm-origin snails survived poorly at 6°C in the common garden experiment and better than cold-origin and seasonal-origin snails in the warm habitat in the reciprocal transplant experiment. Contrary to thermal adaptation models, growth rate in both experiments was highest in the warm populations irrespective of temperature, indicating cogradient variation. The optimal temperatures for growth and reproduction were similar irrespective of origin, but cold-origin snails always had the lowest performance, and seasonal-origin snails often performed at an intermediate level compared to snails originating in either stable environment. Our results indicate that central life-history traits can differ in their mode of evolution, with survival following the predictions of thermal optimality models, whereas ecological constraints have shaped the evolution of growth rates in local populations.