Chromosome studies on some Asteraceae from South America

Mitotic or meiotic chromosome numbers for 42 accessions belonging to 39 species of different genera of Asteraceae were determined. First chromosome counts are reported for one genus ( Gymnocoronis ), 14 species, and one variety. These are as follows: Solidago chilensis var. megapotamica (2 n  = 2 x  = 18), Chromolaena barbacensis (2 n  = 3 x  = 30), Chromolaena christieana (2 n  = 3 x  = 30), Chromolaena hirsuta (2 n  = 4 x  = 40), Chromolaena verbenacea ( n  = 20 II, 2 n  = 4 x  = 40), Disynaphia multicrenulata (2 n  = 2 x  = 20), Gymnocoronis spilanthoides var. subcordata (2 n  = 2 x  = 20), Mikania thapsoides (2 n  = 4 x  = 68), Stevia commixta (2 n  = 2 x  = 22), Porophyllum brevifolium (2 n  = 4 x  = 44), Viguiera rojasii (2 n  = 2 x  = 34), Pterocaulon angustifolium (2 n  = 2 x  = 20), Gochnatia haumaniana (2 n  = 4 x  = 44), Senecio ostenii (2 n  = 4 x  = 40), Senecio pinnatus (2 n  = 8 x  = 80), and Lepidaploa amambaia (2 n  = 2 x  = 28). Chromosome numbers differing from those reported previously in the literature were found in Campuloclinium macrocephalum (2 n  = 2 x  = 20), Melanthera latifolia (2 n  = 4 x  = 60), Chrysolaena flexuosa (2 n  = 2 x  = 20), and Cyrtocymura cincta (2 n  = 4 x  = 40). The relevance of the results is discussed in relation to the available data for each of the analysed taxa. © 2007 The Linnean Society of London, Botanical Journal of the Linnean Society, 2007, 153 , 221–230.     

A new species of Lavatera Sect. Olbia (Medik.) DC. (Malvaceae) from north-east Morocco

As a result of recent fieldwork in north-east Morocco, a new woody Malvaceae species, Lavatera valdesii Molero & J.M. Monts., is described here. The morphological characters that link it to other species in Sect. Olbia (Medik.) DC. are discussed, as are those traditionally used in defining the species that make up this section. A recently described species of this group, Lavatera plazzae Atzei, is established here as a synonym of L. stenopetala Coss. & Durieu ex Batt., a species previously considered as an endemic of east Algeria. On the basis of morphological characters, we propose the exclusion of both L. thuringiaca and L. cashmiriana Cambess. from Sect. Olbia.  © 2007 The Linnean Society of London, Botanical Journal of the Linnean Society , 2007, 153 , 445–454.     

Extensive local‐scale gene flow and long‐term population stability in the intertidal mollusc Katharina tunicata (Mollusca: Polyplacophora)

The dispersal capabilities of intertidal organisms may represent a key factor to their survival in the face of global warming, as species that cannot adapt to the various effects of climate change will have to migrate to track suitable habitat. Although species with pelagic larval phases might be expected to have a greater capacity for dispersal than those with benthic larvae, interspecies comparisons have shown that this is not always the case. Consequently, population genetic approaches are being increasingly used to gain insights into dispersal through studying patterns of gene flow. In the present study, we used nuclear single‐nucleotide polymorphisms (SNPs) and mitochondrial DNA (mtDNA) sequencing to elucidate fine‐scale patterns of genetic variation between populations of the Black Katy Chiton, Katharina tunicata, separated by 15–150 km in south‐west Vancouver Island. Both the nuclear and mitochondrial data sets revealed no genetic differentiation between the populations studied, and an isolation‐with‐migration analysis indicated extensive local‐scale gene flow, suggesting an absence of barriers to dispersal. Population demographic analysis also revealed long‐term population stability through previous periods of climate change associated with the Pleistocene glaciations. Together, the findings of the present study suggest that this high potential for dispersal may allow K. tunicata to respond to current global warming by tracking suitable habitat, consistent with its long‐term demographic stability through previous changes in the Earth's climate. © 2012 The Linnean Society of London, Biological Journal of the Linnean Society, 2012, 106 , 589–597.     

Coarse woody debris in Australian forest ecosystems: A review

Abstract Coarse woody debris (CWD) is the standing and fallen dead wood in a forest and serves an important role in ecosystem functioning. There have been several studies that include estimates of CWD in Australian forests but little synthesis of these results. This paper presents findings from a literature review of CWD and fine litter quantities. Estimates of forest‐floor CWD, snags and litter from the literature are presented for woodland, rainforest, open forest and tall open forest, pine plantation and native hardwood plantation. Mean mass of forest floor CWD in Australian native forests ranged from 19 t ha^?1 in woodland to 134 t ha^?1 in tall open forest. These values were generally within the range of those observed for similar ecosystems in other parts of the world. Quantities in tall open forests were found to be considerably higher than those observed for hardwood forests in North America, and more similar to the amounts reported for coniferous forests with large sized trees on the west coast of the USA and Canada. Mean proportion of total above‐ground biomass as forest floor CWD was approximately 18% in open forests, 16% in tall open forests, 13% in rainforests, and 4% in eucalypt plantations. CWD can be high in exotic pine plantations when there are considerable quantities of residue from previous native forest stands. Mean snag biomass in Australian forests was generally lower than the US mean for snags in conifer forests and higher than hardwood forest. These results are of value for studies of carbon and nutrient stocks and dynamics, habitat values and fire hazards.     

Frost in a future climate: modelling interactive effects of warmer temperatures and rising atmospheric [CO2] on the incidence and severity of frost damage in a temperate evergreen (Eucalyptus pauciflora)

Although plants are more susceptible to frost damage under elevated atmospheric [CO₂], the importance of frost damage under future, warmer climate scenarios is unknown. Accordingly, we used a model to examine the incidence and severity of frost damage to snow gum (Eucalyptus pauciflora) in a sub‐alpine region of Australia for current and future conditions using the A2 IPCC elevated CO₂ and climate change scenario. An existing model for predicting frost effects on E. pauciflora seedlings was adapted to include effects of elevated [CO₂] on acclimation to freezing temperatures, calibrated with field data, and applied to a study region in Victoria using climate scenario data from CSIRO's Global Climate Model C‐CAM for current (1975–2004) and future (2035–2064) 30 years climate sequences. Temperatures below 0 °C were predicted to occur less frequently while the coldest temperatures (i.e. those below ?8 °C) were almost as common in the future as in the current climate. Both elevated [CO₂] and climate warming affected the timing and rates of acclimation and de‐acclimation of snow gum to freezing temperatures, potentially reducing the length of time that plants are fully frost tolerant and increasing the length of the growing season. Despite fewer days when temperatures fall below 0 °C in the future, with consequently fewer damaging frosts with lower average levels of impact, individual weather sequences resulting in widespread plant mortality may still occur. Furthermore, delayed acclimation due to either warming or rising [CO₂] combined with an early severe frost could lead to more frost damage and higher mortality than would occur in current conditions. Effects of elevated [CO₂] on frost damage were greater in autumn, while warming had more effect in spring. Thus, frost damage will continue to be a management issue for plantation and forest management in regions where frosts persist.     

Long‐term moderate nutrient inputs enhance autotrophy in a forested Mediterranean stream

1. The effects of long‐term nutrient addition at moderate levels were examined in the food web of a forested Mediterranean stream. Basal concentrations of N and P were increased twofold (to c. 750 μg N) and threefold (to c. 30 μg P) from ambient concentrations in an experimental reach. Variations in the abundance of microbes (bacteria and algae), meiofauna and macrofauna, microbial processing of organic matter (extracellular enzyme activities) and stoichiometry of biofilms and invertebrates were compared to an upstream control reach during 4 years of artificial nutrient enhancement. 2. Effects were faster in the bacterial compartment but more substantial in the algal compartment. Epilithic algal biomass doubled in the enriched section jointly triggered by nutrients and increased light irradiance in winter and early spring. Only a few animal groups reacted to the enrichment, including the meiofaunal Copepoda, linked to their high use of enriched FPOM, and macrofaunal grazers (Ancylus), which followed the large algal biomass increase. 3. The enrichment caused biofilm phosphatase activity to decrease, while activities related to the use of algal‐related materials (peptidase, β‐glucosidase) increased. Enzymatic activities related to the use of allochthonous organic matter showed only minor and episodic increases. 4. Changes in stoichiometric ratios were apparent in the epilithic compartment, but not in the sand sediment or in the FPOM. Increases in P content were delayed for 9 months in epilithic biofilms and for nearly 2 years in the case of N. 5. After 2 years of enrichment, the flatworm Schmidtea polychroa (predator), oligochaetes (detritivore) and tadpoles of Bufo bufo (grazer) showed higher per cent N. 6. Enrichment effects were produced in spite of flow cessations that occurred commonly in summer. The results show that forested streams subjected to sustained (though minor) nutrient enrichment changed aspects of their biological structure and metabolism and that changes were especially favoured by periods when light was not limiting.     

Pollination ecology of the pre-Pyrenean endemic Petrocoptis montsicciana (Caryophyllaceae): effects of population size

Petrocoptis montsicciana (Caryophyllaceae) is a threatened pre‐Pyrenean endemic that grows exclusively on caves and walls of limestone. We studied its pollination ecology by monitoring phenology and by evaluating pollen and nectar production, pollinator activity (frequency and behaviour of visitors), quantity and quality of pollination services, pollen/ovule ratio, and seed set in response to insect exclusion and self‐compatibility tests. We also analysed the effect of population size on reproductive mechanisms by comparing a large and a small population. Flowers of P. montsicciana produced nectar and were visited by Hymenoptera (79.7%), Diptera (11.5%), and Lepidoptera (8.8%). The most frequent pollinators (60.6% of total visits) were long‐tongued bees of the genus Anthophora. Both populations had a similar range of pollinators. We found a correlation between the number of visited flowers and the number of open flowers per census; 88.7% of pollen grains deposited on the stigmas were conspecific and the main competitor was another chasmophyte plant, Antirrhinum molle. Bagged flowers set seeds but significantly less so than hand‐self‐pollinated and control flowers. Thus, although self‐compatible and self‐pollinated, entomophilous pollination of P. montsicciana is required in order to explain c. 10–40% of total seed set, in accordance with P/O ratio estimations. Bagged flowers from the small population set significantly more seeds than the large one. Visitation rates were lower in the small population, but, unexpectedly, showed higher stigmatic pollen loads and similar or higher seed set. These results suggest an increase of spontaneous selfing rates in the small population, probably favoured by a smaller flower size, which can not only assure reproductive success when pollinators are scarce, but also provide additional potential to adapt to climatic changes. © 2002 The Linnean Society of London, Biological Journal of the Linnean Society, 2002, 76 , 79–90.     

Expressed sequence tag‐derived microsatellites for the cool‐water marine copepod Calanus finmarchicus

The copepod Calanus finmarchicus is the major contributor to zooplankton biomass in the North Atlantic and Norwegian Sea, but recent studies have shown a 70% decrease in abundance as well as a northward shift in the species’ range. Insights into dispersal capabilities gained from population genetic studies will be crucial in predicting the response of C. finmarchicus communities to climate change and, consequently, we have developed a set of expressed sequence tag‐derived microsatellite markers to allow fine‐scale elucidation of population structuring and dispersal. Ten polymorphic markers displayed between two and 19 alleles, with levels of expected heterozygosity ranging from 0.044 to 0.924.     

Taxonomic and nomenclatural notes on Delphinium L

BLANCHE, C. & MOLERO, J., 1993. Taxonomic and nomenclatural notes on Delphinium L. Delphinium viciosoi Pau and Delphinium intrincatum Pau, two poorly known plants from Iran, are typified. A new combination for the latter, Aconitella intrincata (Pau) Blanche & Molero is given. The name Delphinium ambiguum L. should not be attached to the plant known as Delphinium nanum DC, but should be considered as a synonym for Consolida ajacis (L.) Schur (= Delphinium ajacis L.).     

Range expansion due to urbanization: Increased food resources attract Grey‐headed Flying‐foxes (Pteropus poliocephalus) to Melbourne

Abstract Urbanization profoundly alters the biota of areas that become cities and towns. Many species are introduced by humans while indigenous species often decline. Although these changes are well known, the long‐term ecological effects of new species and their interactions are seldom considered and rarely documented. This study examines changes in diversity and temporal availability of the food resources of Pteropus poliocephalus (Grey‐headed Flying‐fox) in the Melbourne region using a variety of historical and current data sources. Our results indicate that urbanization has influenced the distribution, abundance and ecology of P. poliocephalus through a dramatic increase in the quantity and temporal availability of food resources. Prior to European settlement, only 13 species recorded in the range‐wide diet of P. poliocephalus grew in the Melbourne area. Compilations of street‐tree databases indicate that an additional 87 species have been planted on Melbourne’s streets and that there are at least 315 500 trees that are able to provide food for P. poliocephalus. Phenology records indicate that street trees have lengthened the temporal availability of food for P. poliocephalus. A period of natural food scarcity between May and August has been ameliorated by street trees which have provided nectar and a previously absent fruit resource. These changes are likely to be a major factor contributing to the recent range expansion of P. poliocephalus and the establishment of a permanent camp in Melbourne.