Search results for " systematic"

Durch Phenylbors�ure induzierte ?Lanzettbl�ttrigkeit? bei Solanum lycopersicum

1963

Comparative Cytogenetic Analysis of Three Stylommatophoran Slugs (Mollusca, Pulmonata)

2009

system is still controversial because phylogeny and systematic relationships at the family level are poorly understood. Besides morphological studies, ribosomal RNA genes and the H3/H4 histone gene cluster (Ambruster et al., 2005; Wade et al., 2006) have also been used to resolve the relationships within this order. Recently, by comparison of primary sequence of mitochondrial and nuclear genes, Grande et al. (2004) resolved the Stylommatophora as the early split monophyletic sister group of all the other gastropod taxa. Available data on the cytogenetics of Stylommatophora are extremely poor (reviewed by Patterson, 1969, and Thiriot-Quievreux, 2003) and mostly concern the haploid (n) and/ o…

Chemosensory enrichment as a simple and effective way to improve the welfare of captive lizards

2018

2015

Songs in passerine birds are important for territory defense and mating. Speciation rates in oscine passerines are so high, due to cultural evolution, that this bird lineage makes up half of the extant bird species. Leaf warblers are a speciose Old-World passerine family of limited morphological differentiation, so that songs are even more important for species delimitation. We took 16 sonographic traits from song recordings of 80 leaf warbler taxa and correlated them with 15 potentially explanatory variables, pairwise, and in linear models. Based on a well-resolved molecular phylogeny of the same taxa, all pairwise correlations were corrected for relatedness with phylogenetically independe…

Long-term dynamics of pelagic fish density and vendace (Coregonus albula (L.)) stocks in four zones of a lake differing in trawling intensity

2001

– An 11-year time series of hydroacoustic fish density estimates and fisheries statistics of vendace (Coregonus albula (L.)) from four zones of a lake differing in trawling intensity was analyzed in order to test the hypothesis that intensive trawling has detrimental effects on pelagic fish stocks, especially vendace recruitment. The standardized fish density estimate in trawled zones showed no decrease in comparison to the non-trawled zone. No signs of recruitment failure associable with trawling intensity were found. The growth of vendace at the end of the study period was slower than that at the beginning, indicating a higher density, most clearly so in the zone with highest trawling int…

Orthotrichum consobrinumCardot in Western Europe and South-Western Asia

2009

Abstract Orthotrichum consobrinum Cardot, a moss that was earlier considered an endemic to the Sino-Japanese Region, has been found in the north of the Iberian Peninsula (Spain) and in north-eastern Anatolia (Turkey). Comparison of Spanish and Turkish material with eastern Asiatic specimens revealed no relevant morphological differences, and the specimens from both disjunct populations showed the same range of variation of the species attributes. However, the morphological analysis has revealed some distinctive features of the species that had been overlooked in the past. An updated description of this Euro-Asiatic moss is provided here.

Zur Frage der Ein- oder Mehrkernigkeit der Konidiosporen von Claviceps purpurea Tul. (Mutterkorn)

1957

Variation in the Senecio aethnensis group (Asteraceae) along an altitudinal gradient

2003

ABSTRACT The variability of the Senecio aethnensis group was investigated through morphometric analyses of seven populations along an altitudinal transect on Mt. Etna (E Sicily). The data obtained show a separation into two groups, one including the populations of the upper and middle belts, at and above 1700 m, the other including the populations from lower altitudes. In the first group a clinal morphological variation in several reproductive and vegetative characters was observed in relation to altitude. The analysis of leaf characters in progeny cultivated under uniform conditions confirmed the differentiation into the two groups, which are to be treated as separate species, i.e. S. aeth…

Stopover strategies in birds: a review of methods for estimating stopover length

1999

This study categorizes and reviews methods used to estimate stopover length in migratory birds. Stopover length is an important variable in analysing migration strategies. The analysis of the stopover pattern of migratory birds typically attempts to investigate variability in the number of stopovers and in the length of time spent at stopover sites in relation to species, age, sex and body condition. Although the number of capture-recapture studies analysing stopover length has increased substantially, most are analysed using the simple last-first capture method which gives biased estimates. The use of mathematical models to calculate stopover length is uncommon. Most researchers assume hom…

A HYDRAULIC CONDUCTIVITY MODEL POINTS TO POST-NEOGENE SURVIVAL OF THE MEDITERRANEAN OLIVE

2004

Research on the subfossil record and paleoecology of Olea europaea suggests a new interpretation of its history and ecology with reference to the Mediterranean climate since the Neogene. New results are based on the wood anatomy of ancient and extant Olea and a model estimating hydraulic conductance established for wild forms belonging to Olea europaea subsp. europaea. These suggest that during glacial periods wild olive populations survived in protected microenvironments, particularly riparian habitats. Thereafter, the postglacial expansion of olive associated with climatic warming took place from these refuge areas. This new evidence suggests that the continued existence of Olea in Medite…