The effect of ultraviolet-depleted light on the flavonol contents of the cactus species Opuntia wilcoxii and Opuntia violacea

An early investigation at the Biosphere-2 Laboratory, an artificial ecosystem in the Arizona desert, had shown that the flavonoid content of cacti grown in glass-filtered solar light was lower than of cacti grown in normal solar light. This was attributed to the absence of ultraviolet (UV) radiation, which is required for flavonoid biosynthesis. In this study, two species of Opuntia cacti were grown in solar and UV-depleted light, and their flavonol contents of different tissues were determined by HPLC. O. wilcoxii, previously raised in the absence of UV light, was exposed to normal solar light. The flavonol content of young O. wilcoxii pads was 28-fold higher when grown in solar light as compared to UV-depleted light. The flavonol contents of mature outer tissues were only slightly higher. O. violacea, previously raised in solar light, was also maintained in the same UV-depleted artificial ecosystem. The flavonol content after hydrolysis of outer tissues was similar, whether grown in solar light or UV-depleted light. We attribute these responses to different biosynthetic and metabolic rates of young vs. mature plant tissues; slow-growing mature tissues neither produce nor metabolize compounds as quickly as immature tissues. These findings indicate that artificial ecosystems can influence the production of natural products in cultivated plants.     

Accounting for functional connectivity in cross-realm conservation planning in a data poor context: The Cyprus case

In the past years, efforts have been made to include connectivity metrics in conservation planning in order to promote and enhance well-connected systems of protected areas. Connectivity is particularly important for species that rely on more than one realm during their daily or life cycle (multi-realm species). However, conservation plans for the protection of multi-realm species usually involve a single realm, excluding other realms from the prioritization process. Here, we demonstrate an example of cross-realm conservation planning application for the island of Cyprus by taking into account the terrestrial and marine realms and their interface (i.e. coast). Operating within a data-poor context, we use functional connectivity metrics to identify priority areas for the conservation of six multi-realm species, by setting conservation targets simultaneously for the terrestrial and marine realms. MARXAN decision-support tool was used for the identification of the priority areas.Four scenarios were developed to evaluate the impacts of including connectivity in the prioritization process and the effectiveness of the existing coastal/marine protected areas in the achievement of the conservation targets set for the species. All scenarios considered land and sea anthropogenic uses as surrogate costs to influence the prioritization process.Our findings show an increase in the area of the reserve network and, therefore, the cost, when connectivity is included, whilst reducing the total boundary length. Furthermore, the current reserve network fails to achieve conservation targets, particularly for the marine part, which has a substantially smaller protection coverage than the terrestrial part.We conclude that focus should be given in the expansion of the current coastal/marine reserve network following a cross-realm conservation approach. This approach is not only relevant for the conservation of multi-realm species, but also for islandscapes, in particular, where the interdependence between the hinterland and the coast is larger and therefore the magnitude of the impacts generated in one realm and affects the other.     

Invasive maize spotted stem borer Chilo partellus Swinhoe 1885 (Lepidoptera: Crambidae) is the dominant pest in maize agro-system in the Mediterranean Region of Turkey

The maize spotted stem borer Chilo partellus Swinhoe 1885 (Lepidoptera: Crambidae) was recorded for the first time in Turkey in 2014. This pest is described as invasive, especially in the current climate change dispensation. It is important to investigate the population dynamics of C. partellus for better management practices. We studied the species abundance distribution (SAD) models and some biodiversity indices of three major stem bores, C. partellus, Ostrinia nubilalis and Sesamia nonagrioides as these are the most common and major stem borers of maize in the Mediterranean Region. With the help of light traps, weekly catches of the three major maize stem borers were collected during two maize growing seasons (first cropping and second cropping seasons) in 2018 and 2019. The results showed that C. partellus emerged earlier (April-May) and was very dominant throughout the first cropping season of maize. Ostrinia nubilalis and S. nonagrioides emerged late in June-July, and its population remained low throughout the first cropping season. The population structure of all three stem borers was similar throughout the second cropping season of maize. The relative abundance (RA) of C. partellus was significantly higher than that of O. nubilalis and S. nonagrioides in the first cropping (p <.0001) when compared to the second cropping season (p >.05) for both years. In the first cropping season for both years, no SAD model fitted the observed species distribution, although Fisher’s log series was relatively similar. In the second cropping for both years, the geometric series distribution model fitted the observed SAD. The Berger-Parker dominance index was greater for the first cropping season than that of the second, whereas the opposite was true for the Simpson’s evenness and evenness of Pielou. High RA of C. partellus and the geometric series distribution observed in the second cropping are indicative of a possible dominant status of the C. partellus in the Mediterranean Region of Turkey. Our findings indicated that seasonality is a fundamental driving factor influencing the distribution of the three major stem borers of maize in the Mediterranean Region. In addition, the long and warmer winters could be the reason for the dominance of C. partellus as indicated by the diversity indices.     

Temperature and pCO2 jointly affect the emergence and survival of cercariae from a snail host: implications for future parasitic infections in the Humboldt Current system

Ocean warming and acidification are general consequences of rising atmospheric CO₂ concentrations. In addition to future predictions, highly productive systems such as the Humboldt Current System are characterized by important variations in both temperature and pCO₂ level, but how these physical–chemical ocean changes might influence the transmission and survival of parasites has not been assessed. This study experimentally evaluated the effects of temperature (14, 18 and 25 °C) and the combined effects of temperature (∼15 and 20 °C) and pCO₂ level (∼500 and 1400 microatmospheres (µatm) on the emergence and survival of two species of marine trematodes—Echinostomatidae gen. sp. and Philophthalmidae gen. sp.—both of which infect the intertidal snail Echinolittorina peruviana. Snails were collected from intertidal rocky pools in a year-round upwelling area of the northern Humboldt Current System (23°S). Two experiments assessed parasite emergence and survival by simulating emersion-immersion tidal cycles. To assess parasite survival, 2 h old cercariae (on average) were taken from a pool of infected snails incubated at 20–25 °C, and their mortality was recorded every 6 h until all the cercariae were dead. For both species, a trade-off between high emergence and low survival of cercariae was observed in the high temperature treatment. Species-specific responses to the combination of temperature and pCO₂ levels were also observed: the emergence of Echinostomatidae cercariae was highest at 20 °C regardless of the pCO₂ levels. By contrast, the emergence of Philophthalmidae cercariae was highest at elevated pCO₂ (15 and 20 °C), suggesting that CO₂ may react synergistically with temperature, increasing transmission success of this parasite in coastal ecosystems of the Humboldt Current System where water temperature and pH are expected to decrease. In conclusion, our results suggest that integrating temperature-pCO₂ interactions in parasite studies is essential for understanding the consequence of climate change in future marine ecosystem health.     

Apex predator suppression is linked to restructuring of ecosystems via multiple ecological pathways

Removal of apex predators can drive ecological regime shifts owing to compensatory positive and negative population level responses by organisms at lower trophic levels. Despite evidence that apex predators can influence ecosystems though multiple ecological pathways, most studies investigating apex predators’ effects on ecosystems have considered just one pathway in isolation. Here, we provide evidence that lethal control of an apex predator, the dingo Canis dingo, drives shifts in the structure of Australia's tropical‐savannah ecosystems. We compared mammal assemblages and understorey structure at seven paired‐sites. Each site comprised an area where people poisoned dingoes and an area without dingo control. The effects of dingo control on mammals scaled with body size. Where dingoes were poisoned, we found greater activity of herbivorous macropods and feral cats, a mesopredator, but sparser understorey vegetation and lower abundances of native rodents. Our study suggests that ecological cascades arising from apex predators’ suppressive effects on herbivores and mesopredators occur simultaneously. Concordant effects of dingo removal across tropical‐savannah, forest and desert biomes suggest that dingoes once exerted ubiquitous top–down effects across Australia and provides support for calls that top–down forcing should be considered a fundamental process governing ecosystem structure.     

Seed germination ecology and salt stress response in eight Mediterranean populations of Sarcopoterium spinosum (L.) Spach

This study aims to deepen the analysis of seed germination ecology and salinity tolerance of Sarcopoterium spinosum (Rosaceae). Germination tests were conducted to evaluate the effect of the fruit’s spongy tissue and the intraspecific variability in seed germination among eight populations of the species on responses to light and total darkness, constant and alternating temperatures, salt stress and germination recovery. The effect of the presence of the spongy tissue varied among populations, with significant results for seed germination. For all populations, optimum germination temperatures were observed in the range of 10–20°C, indicating that S. spinosum and its germination in the field might occur preferably in the period between autumn and early spring. The high water availability due to rainfall during this period could be a considerable advantage for the seed germination of this species. Seeds of S. spinosum showed the ability to germinate in up to 250 mM NaCl in the substrate, and their ability to recover after salt exposure may be interpreted as adaptation to the coastal habitats in which they generally grow. These results give this species a halo-tolerant character. Great inter-population variability is detected in this study in several aspects, which indicated that the Mediterranean populations of S. spinosum differ considerably and are adapted to their local conditions. This study provides new information about S. spinosum seed ecology, which could help to preserve and apply effective conservation measures for this species, which in several areas of its distribution range is endangered.     

Tindaria kretensis n. sp., a new deep water protobranch (Bivalvia) from the Early Pliocene of Crete (Southern Greece)

Tindaria kretensis n. sp., a minute deep-water protobranch, is described from Early Pliocene marls cropping out in the Voutes section, northern Crete Island. This is one of the few fossil records of Tindaria from the Mediterranean area, the first well documented for the Neogene. Tindaria is an almost cosmopolitan deep-water genus, absent from the modern Mediterranean. Its occurrence in the Early Pliocene is in agreement with what is known about the past psychrospheric conditions in the Mediterranean.     

Context‐dependent biotic interactions control plant abundance across altitudinal environmental gradients

Many biotic interactions influence community structure, yet most distribution models for plants have focused on plant competition or used only abiotic variables to predict plant abundance. Furthermore, biotic interactions are commonly context‐dependent across abiotic gradients. For example, plant–plant interactions can grade from competition to facilitation over temperature gradients. We used a hierarchical Bayesian framework to predict the abundances of 12 plant species across a mountain landscape and test hypotheses on the context‐dependency of biotic interactions over abiotic gradients. We combined field‐based estimates of six biotic interactions (foliar herbivory and pathogen damage, fungal root colonization, fossorial mammal disturbance, plant cover and plant diversity) with abiotic data on climate and soil depth, nutrients and moisture. All biotic interactions were significantly context‐dependent along temperature gradients. Results supported the stress gradient hypothesis: as abiotic stress increased, the strength or direction of the relationship between biotic variables and plant abundance generally switched from negative (suggesting suppressed plant abundance) to positive (suggesting facilitation/mutualism). For half of the species, plant cover was the best predictor of abundance, suggesting that the prior focus on plant–plant interactions is well‐justified. Explicitly incorporating the context‐dependency of biotic interactions generated novel hypotheses about drivers of plant abundance across abiotic gradients and may improve the accuracy of niche models.     

Phytoplankton Fluctuations during an Annual Cycle in the Coastal Lagoon of Cullera (Spain)

The seasonal variation and the vertical distribution of the phytoplanktonic population of the lagoon of Cullera, an elongated coastal lagoon with estuarine circulation of water, has been studied in three sampling stations: mouth, centre and source. Seasonal variation is determined by a marine-freshwater interaction. In winter, the sea influence is important, a marine water wedge of anoxic water arrives at the sampling station located at the source and marine and brackish water species dominate the phytoplankton. Also marine species of zooplankton and fish enter the system, which may then be considered as exploited by the sea. In spring the marine wedge retreats from the source but remains in the centre and mouth, salinity diminishes, vertical mixing persists and phytoplankton is dominated by Cyclotella species. From late spring to autumn the freshwater influence prevails and a sharp stratification of the water is produced in the stations at the mouth and the centre, by means of a steep halocline coincident with an oxycline. The phytoplankton in this period follows a typical succession like those described in freshwater eutrophic lakes. Vertical distribution of phytoplankton is determined by the presence of the oxycline, originated by the marine water wedge, whose depth varies seasonally but which is always present in the mouth and centre of the lagoon; only few species of algae can be found below its level.