Pollen analysis of animal coprolites recovered from vegetation mounds in El-Ga’ab paleolake: evidence for vegetation history of the desert of northern Sudan

In arid zones vegetation mounds are natural indicators for land degradation. Studying plants and animals remains in different strata of these mounds provide information about the past land use in which parts of the natural environment were modified into arable fields and pastures. They are suitable sites for preserving animal coprolites. In this study, two samples of different animal coprolites were collected from vertical trenches in vegetation mounds of Um Hilal and El-Hamra areas of El-Ga’ab depression in northern Sudan. Pollen grain analysis was conducted and eleven species that belong to eight families were identified. Five species recorded for El Hamra area and nine species were identified for Um Hilal area. Most of the pollen grains were identified as Suaeda monoica and Salsola imbricata which are halophytes indicates habitats of high soil salinity in El-Ga’ab depression. These species are still dominant in other law elevated areas of less dry sand dunes. Polygonum sp. Pollens were recorded in Um Hilal area indicating a moist habitat. Record of the comparatively large number of tree pollen grain of Acacia ehrenbergiana indicates no change in the dominant tree species. Presence of the pollen grains of Triticum sp. (wheat) and Heliotropium parciflorum is an evidence for past agricultural activities. This study recommended further intensive investigations of the old dry vegetation mounds distributed in the desert of northern Sudan to reconstruct its palaeoenvironment.

Record of the Non-native Suckermouth armored catfish hybrid Pterygoplichthys pardalis (Castelnau,1985) x Pterygoplichtys disjunctivus (Weber, 1991) (Siluriformes: Loricariidae) in Honduras

Loricariidae is the largest catfish family, with over 1000 species and 80 genera (Fricke & Eschmeyer, 2019). Sailfin catfishes of the genus Pterygoplichthys are armored catfishes, native to temperate and tropical areas of South America, especially the Amazon (Wakida-Kusunoki & del Angel, 2011). Two species of this genus (Pterygoplichthys pardalis (Castelanu, 1855) and P. disjunctivus (Weber, 1991)) are naturally distributed in South America along the lower, middle and upper basin of the entire Amazon River (Wakida-Kusunoki & del Angel, 2008). These armored catfishes, typified by the presence of ossified plates through the body, are considered very successful invaders of rivers and lakes outside their natural range. Their invasion success has been attributed to their morphology, behavior and life history. For instance, their ability to withstand droughts and cold weather by using burrows in river and lake banks they can survive in the moist habitat even when water levels decrease below the opening of the burrows, these survival characteristics of harsh conditions enable them to thrive in native and non-native grounds (Burgess 1989; Hoover & Killgore 2004; Nico & Martin 2001; Sandoval-Huerta et al. 2012). Furthermore, their rapid growth during their first years of life, their reproductive traits such as an extended reproductive period, high egg yield (Rueda-Jasso et al. 2013), and the capability of achieving reproductive maturity at smaller size (Wei et al. 2017) allow introduced populations to become abundant in a short period of time.

Winter-Active Spider Fauna is Affected by Plantation Forest Type

Plantations of non-native trees for commercial use are common practice in Europe. They are known to have severe ecological impacts on arthropod fauna by altering microclimatic conditions and reducing microhabitat diversity. However, the effect of plantation tree species on winter-active fauna is relatively unknown. Spiders are a diverse predatory arthropod taxon with strong effect on their prey populations. The composition of spider communities sensitively indicates changes in habitat structure. We established 40 sampling sites in five non-native pine and five native poplar plantations and collected spiders with pitfall traps for two winters in the Southern part of Hungary. We assessed the average height of vegetation and percentage cover of leaf litter, mosses, herbaceous vegetation, and shrubs to characterize habitat structure. We found species richness and activity density of spiders in the non-native compared to the native plantations, presumably due to the more temperate microclimate in pine than in poplar plantations. However, there was no significant effect of habitat structure and its interaction with forest type on species richness and activity density of spiders. Species composition of non-native and native plantation forests differed significantly. Furthermore, we identified six characteristic spider species of non-native plantations with preference for relatively moist habitat conditions. The single characteristic species, (Agroeca cuprea Menge, 1873) for the native plantations preferred dry and partly shaded habitats. We conclude that the effect of microclimatic differences and prey availability presumably overrides the effect of habitat structure on winter-active spiders.

Abiotic effects on the clear-winged grasshopper (Orthoptera: Acridae) and its fungal pathogen Entomophaga grylli (Entomophthorales: Entomophthoraceae) in an intermountain bunch-grass prairie

The grasshopper, Camnula pellucida Scudder (Orthoptera: Acridae), is a severe pest of small grains and rangeland forage in North America. In a field experiment using cages containing C. pellucida in northwestern Montana, United States of America, we manipulated exposure to the fungal entomopathogen, Entomophaga grylli Fresenius (Entomophthorales: Entomophthoraceae) pathotype 1, temperature using small greenhouses, and moisture for the pathogen with water pillows. Treatment effects on fungal infection (mycosis) rates and grasshopper survivorship were assessed. Water pillows provided additional moist habitat for E. grylli without having an impact on grasshopper performance or the plant biomass and nitrogen content. Number of fungal spores, pathogen-induced mortality rates, and treatment effects on grass biomass and nitrogen content were also measured. Water pillows benefited the pathogen by increasing fungal spore levels by eightfold, which in turn shortened pathogen-exposed grasshopper survival time by half. In contrast, warming reduced fungal spore levels by 50% and subsequently reduced mortality from E. grylli by 67%. However, warmed pathogen-exposed grasshoppers did not exhibit enhanced survival, which may be due, in part, to intraspecific competition among the surviving grasshoppers.

Habitat selection reveals state-dependent foraging trade-offs in a temporally autocorrelated environment

We use theories of risk allocation to inform trade-offs between foraging in a rich and risky habitat versus using a poor but safe alternative. Recent advances in the theory predict that the length of exposure to good or bad conditions governs risk allocation, and thus habitat choice, when patterns of environmental risk are autocorrelated in time. We investigate the effects of these factors with controlled experiments on a small soil arthropod (Folsomia candida). We subjected animals to nine temporally autocorrelated 16-day feeding treatments varying in both the proportion (0.25, 0.50, and 0.75) and duration (short, medium and long intervals) of time when food was present and absent. We assessed foraging trade-offs by the animals' choice of occupying a risky dry habitat with food (rich) versus a safe moist habitat with no food (poor). Irrespective of autocorrelation in conditions, the proportion of time spent with no food primarily determined habitat selection by these collembolans. Our results imply an energetic threshold below which F. candida are forced to forage in rich and risky habitat despite the possibility of mortality through desiccation. The link to energetic thresholds suggests the possibility of employing state-dependent habitat selection as a leading indicator of habitat change.

Vertebrate community on an ice-age Caribbean island

We report 95 vertebrate taxa (13 fishes, 11 reptiles, 63 birds, 8 mammals) from late Pleistocene bone deposits in Sawmill Sink, Abaco, The Bahamas. The >5,000 fossils were recovered by scuba divers on ledges at depths of 27–35 m below sea level. Of the 95 species, 39 (41%) no longer occur on Abaco (4 reptiles, 31 birds, 4 mammals). We estimate that 17 of the 39 losses (all of them birds) are linked to changes during the Pleistocene–Holocene Transition (PHT) (∼15–9 ka) in climate (becoming more warm and moist), habitat (expansion of broadleaf forest at the expense of pine woodland), sea level (rising from −80 m to nearly modern levels), and island area (receding from ∼17,000 km2 to 1,214 km2). The remaining 22 losses likely are related to the presence of humans on Abaco for the past 1,000 y. Thus, the late Holocene arrival of people probably depleted more populations than the dramatic physical and biological changes associated with the PHT.

Effect of the kind of habitat on flowering of Hierochloë repens (Host) Simonkai

Studies on flowering of <i>Hierochloë repens</i> were performed over the years 2005-2007 in five habitats located in Bydgoszcz. The first habitat is a degenerated fresh ryegrass meadow (<i>Arrhenatheretum elatioris</i>). Another one is a degenerated form of initial xerothermic swards (<i>Tunico</i>-<i>Poetum compressae</i>). The third habitat in which the occurrence of <i>Hierochloë repens</i> was found and flowering was analyzed is sandy sward (<i>Koelerio</i>-<i>Corynephoretea</i>). Yet another habitat is ruderal in character and it was located on the side of the road (<i>Convolvulo</i>-<i>Brometum inermis</i>). The last one is a fertile and moist habitat of elm-ash marshy meadow being gramineous herb fringe communities in character. The evaluation was based on the following analyses: morphological characters of inflorescences (length of inflorescence, stem length, number of inflorescence branches and number of spikelets), stem and inflorescence weight and reproduction effort as well as the share of generative individuals in the population and the number of generative individuals per m². Differences were found in the structure of <i>Hierochloë repens</i> inflorescence in the habitats analyzed. The biggest inflorescence, in terms of all the characters analyzed, was found in fertile elm-ash marshy meadow, and the smallest in poor xerothermic sward. The highest generative reproduction potential of <i>Hierochloë repens</i> was found in the ruderal habitats. They are the basic potential source of generative diaspora production, which can affect the spreading of this species in Poland.

Plasma proteins and morphology of Salamandra salamandra in Israel

Differences between three isolated populations of Salamandra salamandra were examined in this study. It is based on 369 adult specimens which were measured for length and weight. The yellow markings and the quantitative relationship between the black and the yellow areas were compared. Plasma proteins were determined by electrophoresis on polyacrylamide gel. Salamanders from a moist habitat (Tel Dan) are much smaller than salamanders from semi-arid habitats (Mt. Meron and Mt. Carmel). The colour pattern typical of the Lebanese S. s. infraimmaculata was found in all the Israeli populations, whereas colour patterns typical of the European S. s. salamandra were not found in them. The plasma proteins of the Israeli salamanders are very similar to those of the Lebanon (Gasser, 1975) and differ greatly from those of the European S. s. salamandra. These results indicate that the Israeli salamander populations should be arranged taxonomically with S. s. infraimmaculata.

Water balance of salamanders (Salamandra salamandra (L.)) from different habitats

Salamanders (Salamandra salamandra) from semi-arid and moist habitat maintained their body weight constant on 40% and 50% field capacity respectively. The water turnover of salamanders from moist habitats (50 % field capacity) was 93 μl.g-1.day-1 and the water turnover of salamanders from semi-arid habitats (40% field capacity) was 47 μl.g-1.day-1 and 49 μl.g-1.day-1. The blood plasma concentration of salamanders from semi-arid habitats was higher than the blood plasma concentration of salamanders from moist habitats when they were found, in water balance, on soil with a low moisture content.