Spatial—temporal marked point processes: a spectrum of stochastic models

Renshaw, Eric

doi:10.1002/env.1019

Cited by 3 publications

(1 citation statement)

References 28 publications

(21 reference statements)

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“…When minimum distances between objects are computable, the statistics described here are applicable to spatial data relating to objects and therefore have a broad applicability, in particular when interactions occur between marginal areas of objects. To advance spatial studies, it is necessary to construct spatial community dynamic models incorporating growth, mortality, reproduction and species interactions (Muko, Sakai & Iwasa ,b; Renshaw, Comas & Mateu ; Renshaw ), based on multispecies spatial data with size variations. Modelling requires summary statistics for estimating maximum likelihood, testing model fit, and other modelling processes (Penttinen, Stoyan & Henttonen ; Shimatani & Kubota ; Comas & Mateu ; Micheas & Wikle ; Waagepetersen & Guan ; Shimatani ).…”

Section: Discussionmentioning

confidence: 99%

Spatial analyses for nonoverlapping objects with size variations and their application to coral communities

Muko

Shimatani

Nozawa

2014

Journal of Animal Ecology

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Summary1. Spatial distributions of individuals are conventionally analysed by representing objects as dimensionless points, in which spatial statistics are based on centre-to-centre distances. 2. However, if organisms expand without overlapping and show size variations, such as is the case for encrusting corals, interobject spacing is crucial for spatial associations where interactions occur. 3. We introduced new pairwise statistics using minimum distances between objects and demonstrated their utility when examining encrusting coral community data. We also calculated the conventional point process statistics and the grid-based statistics to clarify the advantages and limitations of each spatial statistical method. For simplicity, coral colonies were approximated by disks in these demonstrations. 4. Focusing on short-distance effects, the use of minimum distances revealed that almost all coral genera were aggregated at a scale of 1-25 cm. However, when fragmented colonies (ramets) were treated as a genet, a genet-level analysis indicated weak or no aggregation, suggesting that most corals were randomly distributed and that fragmentation was the primary cause of colony aggregations. In contrast, point process statistics showed larger aggregation scales, presumably because centre-to-centre distances included both intercolony spacing and colony sizes (radius). The grid-based statistics were able to quantify the patch (aggregation) scale of colonies, but the scale was strongly affected by the colony size. 5. Our approach quantitatively showed repulsive effects between an aggressive genus and a competitively weak genus, while the grid-based statistics (covariance function) also showed repulsion although the spatial scale indicated from the statistics was not directly interpretable in terms of ecological meaning. 6. The use of minimum distances together with previously proposed spatial statistics helped us to extend our understanding of the spatial patterns of nonoverlapping objects that vary in size and the associated specific scales.

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Section: Discussionmentioning

confidence: 99%

Spatial analyses for nonoverlapping objects with size variations and their application to coral communities

Muko

Shimatani

Nozawa

2014

Journal of Animal Ecology

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Effects of the lack of forest management on spatiotemporal dynamics of a subalpinePinus cembraforest

Giammarchi

Vacchiano

Bertagnolli³

et al. 2016

Scandinavian Journal of Forest Research

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Knowledge about the stand structure and dynamics of subalpine forests is crucial to preserve their 15 multifunctionality. In the present study, we reconstructed the spatio-temporal dynamics of a subalpine Pinus 16 cembra forest in the eastern Italian Alps in response to natural disturbances and forest management. We 17 adopted a concurrent point pattern, dendroecological and growth dominance analysis. We mapped and 18 measured all trees of Pinus cembra and Larix decidua in a 1 ha plot. We analyzed intra-and inter-specific 19 spatial patterns and spatial autocorrelation of tree size and age. We explored establishment dynamics and 20 shifts in competition by analyzing growth suppression/release patterns and growth dominance trends. Results 21 showed a clumped, uneven-aged, multi-layered structure where pine was dominant. The synergic action of 22 ecological and human-induced factors is discussed to explain the prevalence of pine over time. Spatial pattern 23 and autocorrelation analyses suggest a different colonization strategy of the two species, in which pine 24 established after small-scale perturbations and experienced a stronger inter-and intra-specific competition. 25 The interruption of tree establishment and shift in growth dominance towards large trees resulting from the 26 lack of forest management is the most important finding of this research. This highlights the importance of an 27 active management to avoid a homogenization of the forest structure that is generally associated with a 28 reduction of biodiversity and protective ability of forests.

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