1,721,210 research outputs found
Spatial pattern analysis of the herb layer of woodland vegetation using information theory (JNP)
No full textSoil depth shapes plant functional diversity in granite outcrops vegetation of Southwestern Australia
No full textBackground: The arid and nutrient-poor Southwestern Australia is one of the global biodiversity hotspots. Embedded in this landscape, granite outcrops are considered terrestrial insular habitats supporting habitat heterogeneity when compared to the more homogenous surrounds. Ecology of plant species and communities on granite outcrops has been addressed in numerous studies. However, functional diversity (FD) in context of the environmental heterogeneity remained unexplored. Aims: We tested whether mesic deep-soil habitats on granite outcrops can sustain larger FD than dry shallow-soil habitats. Methods: We calculated FD for dominant species for five single traits (leaf dry matter content, foliar δ13C, foliar C:N ratio, plant height and specific leaf area) and their combinations. We employed Generalized Additive Mixed Models to quantify the relationship between selected climate and soil depth variables, and FD. Results: More benign (deep-soil) habitats supported larger FD for foliar C:N, plant height and for multiple traits than did shallow-soil habitats. Conclusions: We suggest that: (1) functional diversification, likely aimed at avoiding intra- and interspecific competition for light and nutrients acquisition, might be the important factor in deep-soil habitats; (2) deep-soils patches on and around granite outcrops may serve as ecological microrefugia for biota associated with resource-rich environments.</p
On the importance of fine-scale spatial complexity in vegetation restoration studies
No full textEffective restoration should start from an understanding of the spontaneous processes of vegetation succession and
utilize the natural “self-repair” mechanisms. The number of possible restoration treatments (for example,
manipulating the level of soil nutrients, propagule sources or disturbance regime) is limited. However, the relatively
constant treatments should interact with a great variability of ecosystem states and landscape contexts, making
restoration practice a very challenging and hard task. This context dependence of local vegetation dynamics is
emphasized by the non-equilibrium ecological paradigm. This paradigm views the developing plant community as
a complex dissipative system, which involve a methodology with explicit representation of spatiotemporal patterns.
Restoration practice needs simple methods that easy to implement in the routine. However, there is a conflict
between the simplicity required by the application and the complexity offered by advanced theory. We propose a
solution based on the information theory models of Juhász-Nagy. These models are able to represent complex
community patterns in a very simple way. The frequency distribution of species combinations within the community
is detected as a function of spatial resolution. Comparing the pattern of species combinations detected in the field
with other reference patterns generated by neutral models, we are able to quantify and interpret constraints of
vegetation dynamics in an explicit, detailed way. The related information theory models are additive that makes the
calculations easy. The basic models are very simple and practical in routine works. Nevertheless the more advanced
models of the model family can be connected with spatially explicit individual based models and with advanced
techniques analysing complex trajectories in abstract coenostate spaces. The pattern of species combinations can
be sampled with long transects in the field. This sampling is rapid and causes minimum sampling disturbance,
therefore applicable for the long-term monitoring of restoration experiments as well. We present some case studies
to illustrate the application and the interpretation of results. This methodology enables us to study non-equilibrium
dynamics and assembly rules of vegetation in a more operative way. Taking into account the structural constraints
detected by Juhász-Nagy’s models we intend to improve the predictability of the processes, and the effectiveness
of restoration treatments
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
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