Female social dominance over males can only be found in a small number of mammalian species, but is unusually concentrated among Malagasy lemurs. Three major hypotheses are currently discussed to ...explain this phenomenon, namely the energy conservation hypothesis, sleeping site hypothesis and ancestral lemur condition hypothesis. Since proximate determinants of female dominance have rarely been studied, this study aimed to investigate the influence of factors connected to these hypotheses, focusing on sex-specific differences in energy requirements and group composition in two closely related nocturnal lemur species. More specifically, the effects of species, season and age on agonistic behaviour and the expression of female dominance were tested, while the effects of individuality, body mass, breeding experience and habituation were controlled. Seasonal variations in intersexual dominance relationships were investigated in captivity in grey mouse lemurs, Microcebus murinus, a prominent female-dominant species, and Goodman's mouse lemurs, Microcebus lehilahytsara, whose agonistic behaviour was studied for the first time. Data were collected during a series of encounter experiments between one male and one female (15 dyads of M. murinus and nine of M. lehilahytsara) during the reproductive and nonreproductive seasons. Moderate female dominance was expressed in both species with females winning the majority of conflicts year round, independently of context. However, effects of season and species were found in conflict rates, in the probability for females to win conflicts, and in the number of dominant females. Moreover, the age difference between dyad partners and the breeding experience of females influenced whether conflicts were decided in favour of males or females. It can be concluded that female dominance probably represents an ancestral trait in mouse lemurs and it is proposed that its evolution might have been driven by sex-specific energetic constraints prevailing in the species-specific ancestral habitats, and may moreover be influenced by the species-specific social organization.
•Potential determinants of female dominance in mouse lemurs are presented.•Female dominance is influenced by species and season.•Older and sexually experienced females win more conflicts than male partners.•This rare behaviour probably represents an ancestral trait in the genus Microcebus.•Evolution might be driven by different energetic constraints and social organization.
Full text
Available for:
GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
The high-biodiversity phenomenon of the Balkan Peninsula is a result of the past and present topographic, climatic and geological conditions, as well as human impact. The Dinaric Alps, as a part of ...the Balkan Peninsula, harbour a high number of endemic species, some of them comprising a small number of populations, which are often endangered. We investigated spatial distribution, community composition, site ecology, genetic diversity and conservation of
Degenia velebitica
, a stenoendemic species of the north-western Dinaric Alps. Our results showed that
D. velebitica
is nowadays restricted to three localities with the area of occupancy of 48,560 m
2
, harbouring approximately 37,000 individuals.
Degenia velebitica
stands are differentiated into three well-characterized, floristically homogenous syntaxa, very distinct from the surrounding vegetation, suggesting their azonal occurrence and restriction to spatially highly fragmented microsites exposed to stormy winds. Spatial distances of populations, differences in
D. velebitica
community composition and site ecology are mirrored in genetic variation patterns of the populations, such as high-frequency down-weighted marker values in the north-western populations and high gene diversity in the south-eastern group of populations. The fact that we could not find a single
D. velebitica
individual at the
locus classicus
indicates the existence of the ever-growing fragmentation. The analyses of genetic structure using AFLP data recognized two main genetic groups of populations as evolutionary significant units that should be considered when planning protection measures. According to our IUCN Red List reassessment,
D. velebitica
should be treated as a critically endangered species that requires immediate conservation actions.
Full text
Available for:
DOBA, EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, IZUM, KILJ, KISLJ, MFDPS, NLZOH, NUK, OBVAL, OILJ, PILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UILJ, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
Three hundred and seventy-seven tree-ring width site chronologies including all eight principal forest tree species within Central Europe (5° to 15°E; 43° to 53°N) are expressed as Cropper-values and ...mapped using a Geographical Information System (here after referred to as GIS). Spatial classification of positive and negative growth anomalies and their occurrence within altitudinal zones, results in nine differing sub-groups of pointer years. In total, 39 years between 1901 and 1971AD are subdivided into these groups. The other 32 years show only growth anomalies in less than 40% of the research area, and therefore were excluded from further investigations.
Climatological interpretation of the growth patterns of the nine groups documents mutual temperature and precipitation forcings. Extreme positive pointer years represent optimal growth conditions, i.e., moderate cool and wet conditions during the growing season. For the other years we summarize (i) warm and wet (warm and dry) springs result in positive (negative) anomalies in the Central European lowlands and (ii) warm (cold) summers result in positive (negative) anomalies in the Central European highlands. In some years, however, similar climatological conditions yield to divergent growth response patterns.
Full text
Available for:
GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
Various factors, such as climate, body size and sociality are often linked to parasitism. This constrains the identification of other determinants driving parasite infections. Here, we investigate ...for the first time intestinal parasites in two sympatric arboreal primate species, which share similar activity patterns, feeding ecology, body size and sociality, and cope with the same climate conditions, but differ in sleeping site ecology: the Milne-Edward's sportive lemur (Lepilemur edwardsi) and the Western woolly lemur (Avahi occidentalis). Comparison of these two species aimed to test whether differences in sleeping sites are related to differences in parasite infection patterns. Additionally, gender and seasonal factors were taken into account. Animals were radio-collared to record their sleeping site dynamics and to collect fecal samples to assess intestinal parasitism during both the dry and the rainy season.
Only low parasite diversity was detected, which is attributable to the strict arboreal lifestyle of these lemurs, limiting their contact with infective parasite stages. L. edwardsi, which sleeps in tree holes and repeatedly uses the same sleeping site, excreted eggs of strongyle and oxyurid nematodes, whereby strongyles always occurred in coinfection with oxyurids. In contrast, A. occidentalis, which sleeps on open branches and frequently changes sleeping sites, only excreted eggs of strongyle nematodes. This difference can be attributed to a potential favorable environment presented by tree holes for infective stages, facilitating parasitic transmission. Additionally, Strongylida in A. occidentalis were only observed in the rainy season, suggesting an arrested development during the dry season in the nematodes' life cycle. Males and females of both lemur species showed the same frequency of parasitism. No differences in body mass of infected and non-infected individuals were observed, indicating that the animals' body condition remains unaffected by the detected gastrointestinal parasites.
The comparison of two primate hosts with a very similar lifestyle suggests an influence of the sleeping site ecology on intestinal parasites. In A. occidentalis there was a clear seasonal difference in strongyle egg excretion. These results improve our understanding of the parasite ecology in these endangered primate species, which may be critical in the light of species conservation.
Questions: Can forest site characteristics be used to predict Ellenberg indicator values for soil moisture? Which is the best averaged mean value for modelling? Does the distribution of soil moisture ...depend on spatial information? Location: Bavarian Alps, Germany. Methods: We used topographic, climatic and edaphic variables to model the mean soil moisture value as found on 1505 forest plots from the database WINALPecobase. All predictor variables were taken from area-wide geodata layers so that the model can be applied to some 250 000 ha of forest in the target region. We adopted methods developed in species distribution modelling to regionalize Ellenberg indicator values. Therefore, we use the additive georegression framework for spatial prediction of Ellenberg values with the R-library mboost, which is a feasible way to consider environmental effects, spatial autocorrelation, predictor interactions and non-stationarity simultaneously in our data. The framework is much more flexible than established statistical and machine-learning models in species distribution modelling. We estimated five different mboost models reflecting different model structures on 50 bootstrap samples in each case. Results: Median R 2 values calculated on independent test samples ranged from 0.28 to 0.45. Our results show a significant influence of interactions and non-stationarity in addition to environmental covariates. Unweighted mean indicator values can be modelled better than abundance-weighted values, and the consideration of bryophytes did not improve model performance. Partial response curves indicate meaningful dependencies between moisture indicator values and environmental covariates. However, mean indicator values <4.5 and >6.0 could not be modelled correctly, since they were poorly represented in our calibration sample. The final map represents high-resolution information of site hydrological conditions. Conclusions: Indicator values offer an effect-oriented alternative to physically-based hydrological models to predict water-related site conditions, even at landscape scale. The presented approach is applicable to all kinds of Ellenberg indicator values. Therefore, it is a significant step towards a new generation of models of forest site types and potential natural vegetation.
Full text
Available for:
BFBNIB, DOBA, FZAB, GIS, IJS, IZUM, KILJ, NLZOH, NMLJ, NUK, OILJ, PILJ, PNG, SAZU, SBCE, SBMB, UILJ, UKNU, UL, UM, UPUK
Variations in ring width and ring coloration of 89 spruce trees from six sites in the Lötschental, Switzerland, are analyzed. Sites are located along an altitudinal transect spanning 1500 to 2000m ...a.s.l. on a SSE- and a NNW-facing slope. Site ecology is further determined by local differences in micro relief, allowing differentiation into locally wet and dry sites. Growth reactions are classified as “site pointer years” representing extreme years common within a site, and as “valley pointer years” representing extreme years common between sites. These site and valley pointer years are classified and analyzed separately for ring width, light rings and dark rings. In so doing, 44 ring width and 9 light ring pointer years are reported for the 20th century. Dark rings do not crossdate within sites, so that no such pointer year is documented. Comparisons with instrumental data show that May precipitation and temperatures are crucial for both negative and positive ring width pointer years. Climate variability in all other months only modifies the intensity of these pointer years. Light ring pointer years correlate with low temperatures recorded towards the end of the growing season, particularly in September. By further analyzing the climate response patterns of site and valley pointer years, a conceptual classification of six climate/pointer year groups is presented:
(1)Moderately cold and moist growing seasons cause wide rings at upper and lower sites.
(2)A cold May followed by moderately cool summers cause wide rings at lower sites.
(3)Warm (and moist) summers cause wide rings at upper sites.
(4)Warm and dry summers cause narrow rings at lower sites.
(5)Cold and moist summers cause narrow rings at upper sites.
(6)A cold September cause light rings at upper sites.
Full text
Available for:
GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
Based on a stratified random sample of 93 vegetation plots and coincident measurements of ecological conditions in mountain forests of the Bavarian Alps, the degree to which species composition and ...Ellenberg indicator values derived thereof were related to measured environmental variables was assessed for vascular understorey plants and epigeic bryophytes. According to Mantel tests vascular composition contained ca. 30% more ecological information than bryophyte composition. When expressed as average Ellenberg or Düll values, vascular plant-based values reflected 60% more of measured variables than bryophyte-based values. The differences remained after rarefaction of the vascular matrix to the gamma diversity of bryophytes, showing that indication is not a function of indicator richness. Analysing vascular plants and bryophytes combined yielded very similar, or even slightly less stringent relationships with the environment than using vascular plants only.
Bivariate relationships of indicator values with corresponding ecological measurements confirmed the specific potential of the values to estimate ecological factors from both plant groups, but vascular plants performed better for all factors. Bryophyte indication was particularly poor for light, temperature and base saturation. Bryophyte-based indicator values did not significantly predict the residuals of measured ecological variables against vascular plant-based Ellenberg values.
For the study region, it is concluded that indicator values of vascular forest understorey should be used without consideration of Düll's indicator values for epigeic bryopyhtes. There appears to be potential to improve bioindication by recalibrating indicator values of epigeic bryophytes based on ecological measurements and vascular plant indicator values.
Auf Grundlage einer stratifizierten Zufallsstichprobe von 93 Vegetationsaufnahmen und zugehörigen ökologischen Messungen in Bergwäldern der Bayerischen Alpen wurde die Übereinstimmung zwischen Artenzusammensetzung bzw. mittleren Ellenberg-Zeigerwerten und gemessenen Umweltvariablen getrennt für Gefäßpflanzen der Feldschicht und bodenbewohnende Moose untersucht. Mantel-Tests zufolge spiegelt die Artenzusammensetzung der Gefäßpflanzen ca. 30% mehr Varianz in den Umweltbedingungen wider als die der Moose. In der Zusammenfassung als Ellenberg- (bzw. Düll-) Zeigerwerte entsprechen die Gefäßpflanzen-basierten Werte den Messwerten sogar zu 60% genauer als die auf Moosen beruhenden. Diese Unterschiede bleiben nach einer zufälligen Ausdünnung der Gefäßpflanzenmatrix auf die Gesamtartenzahl der Moose im Datensatz bestehen, was zeigt, dass es sich nicht um eine Funktion der Zeigerartenvielfalt handelt. Die gemeinsame Analyse von Gefäßpflanzen und Moosen erbrachte sehr ähnliche oder sogar etwas schwächere Beziehungen zu gemessenen Größen als bei Verwendung der Gefäßpflanzen allein.
Bivariate Beziehungen der Zeigerwerte mit den entsprechenden Messwerten bestätigten das Potential, bestimmte ökogologische Faktoren gezielt aus dem Artenbestand beider Gruppen zu schätzen, jedoch schnitten dabei die Gefäßpflanzen stets besser ab als die Moose. Die Indikation durch Moose war vergleichsweise gut für Bodenreaktion und Feuchte, vergleichsweise schlecht für Licht, Temperatur und Basensättigung. Die Moos-basierten Zeigerwerte waren nicht signifikant geeignet, um die Residuen der gemessenen Umweltvariablen gegen die Gefäßpflanzen-basierten Zeigerwerte vorherzusagen.
Im betrachteten Naturraum ist eine Ergänzung der Ellenberg-Zahlen der Gefäßpflanzen durch zusätzliche Berücksichtigung der Düll'schen Moos-Zeigerwerte nicht zu empfehlen. Die Analysen weisen gleichwohl darauf hin, dass die Bioindikation durch eine Neueichung von Zeigerwerten für epigäische Moose auf Basis von ökologischen Messungen oder Gefäßpflanzen-basierten Zeigerwerten durchaus verbessert werden könnte.
Full text
Available for:
GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
Using a representative sample of stands from a cross section through the Bavarian portion of the northern Calcareous Alps, this study evaluates the plausibility and significance of causal hypotheses ...for an explanation of the poor crown condition of Norway spruce in mountain forests: (1) ozone exposure in conjunction with (a) drought and (b) ample water supply; (2) soil-borne nutrient deficiency; (3) drought; and (4) tree age. Site index and, in a subset of stands, foliar nutrient concentrations are considered as additional indicators of tree vigour. According to principal component analysis and multiple regression, crown condition was controlled by soil chemistry (transparency increased towards shallow calcareous soils), stand age and, to a smaller degree, by an interaction between ozone exposure and drought. Site index was best explained by a model including elevation, soil chemistry and drought. Tree nutrition clearly reflected the main soil chemical gradient, and P, N and Fe deficiencies were found in transparent stands, which had markedly smaller needles. The similar distributions of crown transparency, site index and nutrition present a strong argument for the hypothesis that soil chemistry has constrained the vigour of spruce trees in the Calcareous Alps for a long time. By leaving unproductive stands to age naturally, forest management has accentuated the pattern of crown condition. In the heterogeneous alpine landscape, possible effects of recent increases in ozone exposure have to be viewed extremely carefully against the background of these natural and anthropogenic covariables.PUBLICATION ABSTRACT
Full text
Available for:
EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
PDF
