Understanding and predicting ecological dynamics: are major surprises inevitable?

Ecological surprises, substantial and unanticipated changes in the abundance of one or more species that result from previously unsuspected processes, are a common outcome of both experiments and observations in community and population ecology. Here, we give examples of such surprises along with the results of a survey of well-established field ecologists, most of whom have encountered one or more surprises over the course of their careers. Truly surprising results are common enough to require their consideration in any reasonable effort to characterize nature and manage natural resources. We classify surprises as dynamic-, pattern-, or intervention-based, and we speculate on the common processes that cause ecological systems to so often surprise us. A long-standing and still growing concern in the ecological literature is how best to make predictions of future population and community dynamics. Although most work on this subject involves statistical aspects of data analysis and modeling, the frequency and nature of ecological surprises imply that uncertainty cannot be easily tamed through improved analytical procedures, and that prudent management of both exploited and conserved communities will require precautionary and adaptive management approaches.     

Recycling of an acrylate–glass fiber reinforced polyester composite

Journal of Material Cycles and Waste Management - Recycling possibilities were evaluated for a composite waste composed of glass fiber reinforced polyester bound to a layer of crosslinked...     

Leaf reddening in the seagrass Thalassia testudinum in relation to anthocyanins, seagrass physiology and morphology, and plant protection

Numerous seagrass species growing in high-light environments develop red coloration in otherwise green leaves, yet the ecophysiology of leaf reddening in seagrasses is poorly understood. To increase our understanding of the process of leaf reddening in Thalassia testudinum found in the lower Florida Keys (USA), we identified the molecules responsible for red coloration in leaves and compared physiological, morphological, and growth attributes of entirely red-leafed shoots to entirely green-leafed shoots. We determined that four anthocyanin molecules are responsible for red coloration in leaves. In addition, we found that red leaves had higher concentrations of photoprotective pigments (anthocyanins and UV-absorbing compounds), higher effective quantum yields (ΔF/F _m′) at midday, and were shorter, narrower, and weighed less than green leaves. No significant difference in growth rates was observed between red- and green-leafed shoots, but patches of red-leafed shoots had shorter canopy heights and smaller LAI compared to patches of green-leafed shoots. Our results demonstrate that leaf reddening in T. testudinum is caused by high concentrations of anthocyanins, is associated with physiological and morphological attributes, and acts as a sunscreen since red leaves were able to maintain high effective quantum yields at high light intensities.     

Promiscuous behaviour disrupts pregnancy block in domestic horse mares

Based on questionnaires from horse breeders, we found that bringing a pregnant mare which had been mated away from home into a vicinity of a familiar male who was not the father of her foetus increased probability of pregnancy disruption. These mares aborted in 31% of cases, while none of those mated within the home stable aborted. Repeated sexual activity either by a stallion or dominant gelding from the normal home group was observed shortly after the mare came from away-mating. Pregnant mares isolated from home males by a fence were even seen soliciting them over the fence. We speculate that, once returned to the home “herd”, and introduced to familiar males, mares were more likely to terminate their pregnancy to save energy and avoid likely future infanticidal loss of their progeny by dominant male(s) of the home social group. This is a newly discovered phenomenon where a mare manipulates the male’s paternity assessment by promiscuous mating. It may explain a common increased incidence of foetal loss in domestic horses occurring in nearly 40% of pregnancies. We conclude that the common practice of transporting the mare for mating and then bringing her back to an environment with males, stallions or geldings, which did not sire the foetus, is the main cause of high percentages of pregnancy disruption in domestic horses.     

Decrease in air pollution load in urban environment of Bratislava (Slovakia) inferred from accumulation of metal elements in lichens

The study illustrates the response of epiphytic lichens to changing atmospheric conditions in Central Europe, where the emission of air pollutants has significantly decreased from 1990, in the area in and around Bratislava City. Variation in concentrations of seven metal elements (Cu, Cd, Cr, Mn, Ni, Pb and Zn) in the thalli of Evernia prunastri, Hypogymnia physodes and Parmelia sulcata is assessed. Samples of these species were exposed in lichen bags in 39 sites throughout the territory of the city (more than 300 km(2)) during the period December 2006-February 2007. The samples were analyzed by AAS for metal element contents prior to and after exposure. The decrease in air pollution (for all studied elements by more than 90%) corresponded to a decrease in the accumulation of elements in lichen thalli, e.g. the contents of Pb decreased by 69% and of Cd by 34% on average. The results show also variations in accumulation between with different lichen species. The background values of metal element contents in thalli of H. physodes growing in situ were measured in semi-natural sites in Slovakia. It is suggested that these can be used as a reference in large-scale monitoring studies in Central Europe. Analysis of compatible data from the current study, and the study performed at the end of 1990s shows a significant decrease of metal elements in the air pollution load.     

Soil washing: Practical considerations and pitfalls

The use of soil washing to remove petroleum hydrocarbon contamination from the soil matrix is becoming more widely used. When viewed as a volume reduction tool, this technology shows some promise. However, ongoing research and treatability studies indicate that without further treatment, even larger-sized soil fractions (sands and cobbles) may retain hydrocarbon contamination at levels that require further cleaning prior to permanent disposal or reuse. The perception has been that by removing the sand from the soil matrix, thus achieving a 30 percent to 60 percent volume reduction, expensive post-washing treatment or approved disposal of the finer materials (silts and clays) would be cost-effective. There exists evidence to the contrary, however. Hydrocarbon retention after soil washing may be influenced by a number of factors unrelated to particle size. Soil characteristics that may play a role include soil humic acids, metal oxide coatings, geologic origin of the soil particles, and clay type. In this article the authors describe a laboratory study designed to evaluate the “cleanability” of two soils.     

Effect of biopolymer on the dewatering characteristics of autothermal thermophilic aerobic digestion of sludges.

Autothermal thermophilic aerobic digestion of sludge is known to produce poorly dewatering sludges. Laboratory studies were conducted to investigate the reasons for the poor dewatering. It was found that, during digestion, proteins and polysaccharides were released into solution, and that these could be linked to the deterioration in dewatering. The biopolymer release was accompanied by an increase in the monovalent-to-divalent (M/D) cation ratio. The degree to which the M/D caused deterioration of the sludges depended on the presence of iron in sludge. When the iron content was high, the release of protein and polysaccharides was low. When iron was low, the release of protein and polysaccharides increased linearly with the M/D ratio. The dose of conditioning chemicals, cationic polymer or ferric chloride, was related to the amount of colloidal biopolymer present in solution. The findings suggest that the addition of iron during the digestion process has the potential to produce better dewatering sludges.     

Cranial pneumatization and auditory perceptions of the oviraptorid dinosaur <Emphasis Type="Italic">Conchoraptor gracilis</Emphasis> (Theropoda,Maniraptora) from the Late Cretaceous of Mongolia

The distribution of air-filled structures in the craniofacial and neurocranial bones of the oviraptorid ZPAL MgD-I/95, discovered at the Hermiin Tsav locality, Mongolia, is restored. Based on the complete obliteration of most of the cranial sutures, the specimen is identified as an adult individual of Conchoraptor gracilis Barsbold 1986. Except for the orbitosphenoids and epipterygoids, the preserved bones of the neurocranium are hollow. Three types of tympanic recess are present in Conchoraptor, a characteristic shared with troodontids, dromaeosaurids, and avian theropods. The contralateral middle ear cavities are interconnected by the supraencephalic pathway that passes through the dorsal tympanic recesses, the posterodorsal prootic sinuses and the parietal sinus. The spatial arrangements of the middle ear cavity and a derived neurocranial pneumatic system in Conchoraptor indicate enhancements of acoustic perception in the lower-frequency registers and of auditory directionality. We further speculate that this improvement of binaural hearing could be explained as an adaptation required for accurate detection of prey and/or predators under conditions of low illumination. The other potentially pneumatic structures of the Conchoraptor cranium include (1) recessus-like irregularities on the dorsal surface of the nasal and frontal bones (a putative oviraptorid synapomorphy; pos); (2) a subotic recess; (3) a sub-condylar recess; and (4) a posterior condylar recess (pos). Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.