On phylogenetic inertia: a case of Lixinae weevils

Summary. Among host plants of Lixinae weevils, plant life-form ratio (sensu Raunkiaer) is similar to the plant spectrum of Mediterranean deserts. A possible explanation is that this group of insects formed in desert zones and settled in the steppe rather later. For the first time Raunkiaer’s life-form ratio is compared with a spectrum of food plants of herbivores. This approach may be useful for reconstruction of the genesis of taxa and communities.     

Phylogenetic structure of Brazilian savannas under different fire regimes

Questions: Fire is a strong filter in fire‐prone communities and is expected to assemble closely related species when functional traits are conserved in plant lineages. Do frequent fires assemble savannas with closely related species (phylogenetic clustering)? If so, what are the clades pruned by fire in the phylogenetic trees? Are species of semi‐deciduous seasonal forests, where fires are not frequent, less related than expected by chance (phylogenetic over‐dispersion)? Are life forms conserved in the phylogeny of the species? Location: Central and SE Brazilian savannas (Emas National Park, 18°18′S, 52°54′W; Brasília, 15°56′–15°57′S, 47°53′–47°56′W and Corumbataí‐Itirapina, 22°13′–22°15′S, 47°37′–47°39′W); and close semi‐deciduous seasonal forests (in Pirenópolis, 15°45′S, 49°04′W; Brasília, 15°33′S, 47°51′W; and São Carlos, 21°55′S, 47°48′W). Methods: We recorded woody species in savannas under different fire regimes and in semi‐deciduous seasonal forests. We obtained data from the literature and from field sampling. We compared mean phylogenetic distance of species of savanna and of nearby semi‐deciduous seasonal forest sites. We obtained significance by randomizing the species among the tips of phylogenetic trees. We also assessed whether life forms were evolutionary conserved across phylogeny of the studied plants (phylogenetic signal) with tests based on the variance of phylogenetic independent contrasts. Results: Some sites of savanna under high fire frequency were characterized by phylogenetic over‐dispersion of woody species whereas, in contrast, some sites of semi‐deciduous seasonal forest were characterized by phylogenetic clustering. We found phylogenetic signals in the traits across the phylogeny of the 801 species investigated. Conclusion: Fire may have different roles in assembling plant species in Brazilian savannas than in other fire‐prone communities. We postulate that the absence of phylogenetic clustering in the cerrado is mainly due to the persistence of long‐lived resprouting species from different plant lineages.     

Plant biodiversity in a larch plantation from the view point of photosynthetic nitrogen use efficiency in northeast China

Forest floor of larch species often provides growth habitat for many kinds of understory species because of relatively sparse structure in a larch canopy. A rich flora of forest understory species may play an essential role in maintaining fertility of a larch stand. An attempt was made to evaluate photosynthetic nitrogen use efficiency (PNUE) of many understory and overstory species according to their Raunkiaer lifeform. By studying 72 perennial deciduous species in a larch plantation in northeast China, marked photosynthetic differences between phanerophytes (Ph) and other three lifeforms of chamaephytes (Ch), hemicryptophytes (He), and cryptophytes (Cr) were found, with marginal differences found among Ch, He, and Cr. Ph species had much lower PNUE, and much lower values of rate of nitrogen allocation to chlorophyll (Chl./N) and nitrogen allocation to carboxylation processes (V _cmax/N) were concurrently observed in Ph compared with the other three lifeforms. Ph had much lower leaf nitrogen per unit of projection area (N _area) and specific leaf area (SLA, cm² g^–1). At lower SLA, for Ph species the change of PNUE with SLA was small, but these changes became very large at higher SLA for Ch, He, and Cr species. Our findings indicate that leaf morphological change is important for clarifying photosynthesis differences among species with different lifeform.     

Spatial patterns along an elevation gradient in high altitude grasslands,Brazil

The Brazilian high altitude grasslands are important biodiversity centers that contribute to human well‐being far outside their boundaries. They host many vulnerable species that may go locally extinct as a result of small changes in the environment. Performing studies on local species distribution is important to guide biodiversity conservation in these areas. This study aimed to characterize a high altitude grassland plant community along an elevation gradient in southeastern Brazil. Simple logistic regression, chi‐squared tests and indicator species analysis were performed to investigate respectively whether: 1) the occurrence of botanical families was related to the altitude; 2) the richness and abundance of life forms varied along the gradient and 3) there were populations associated with specific altitudinal belts. Rubiaceae and Polygalaceae had higher occurrence probability at higher altitudes. Hemicryptophytes and chamaephytes seem to be the most favored life forms under local extreme conditions such as low temperatures and drought. The vegetation spectra varied significantly along the gradient, highlighting the major role of the turnover of habitats on a local scale for the underlying patterns of species distribution. Upper elevations encompassed a high number of indicator species, and further analyses of indicator species of high altitude grasslands will provide clues about adaptability of local species, important to consider in ecosystem management and conservation.