Nestedness analysis as a tool to identify ecological gradients

Ulrich, Werner

doi:10.2478/v10090-009-0015-y

Cited by 22 publications

(34 citation statements)

References 38 publications

(56 reference statements)

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“…While at least 10 metrics have been used to assess whether species assemblages exhibit nestedness , we simplified our analyses by using four nestedness metrics. (1) Matrix temperature ( T ) is a measure of disorder in a data matrix ranging from perfect nestedness ( T = 0°) to maximum disorder ( T = 100°), with intermediate temperatures indicating a combination of order and disorder of the species assemblage . To calculate T of the packed matrix we used ANINHADO .…”

Section: Methodsmentioning

confidence: 99%

Nestedness in sessile and periphytic rotifer communities: A meta‐analysis

Meksuwan

Pholpunthin

Walsh

et al. 2014

Internat. Rev. Hydrobiol.

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The freshwater littoral comprises a mosaic of habitats structured at several scales by a combination of hydrophyte architecture and physiology. Within this complex environment littoral invertebrates should distribute themselves to maximize fitness: that is, for sessile animals selection of permanent substrata is critical, while distribution of motile (periphytic) animals should follow predictions of Ideal Free Distribution theory. Here we explore the relationships between littoral rotifers and hydrophytes by conducting nestedness analyses on 10 published datasets (7 sessile; 3 periphytic); one dataset each of microcrustaceans and insects were included for comparison. We used four metrics to assess nestedness: mean matrix temperature (T); counts of discrepancy shifts and species segregation; and percent singletons. Six sessile rotifer datasets exhibited nestedness (T ¼ 9.25-30.2°, supported by !2 null models; the other metrics varied widely). Our results indicate that distribution of sessile rotifers and periphytic insects was highly structured, but until more data is available little can be said about the distribution of the periphytic rotifer or microcrustacean community structure. Sessile rotifer species possessing idiosyncratic temperatures (T>T þ1.5 SD) exhibited a trend toward a record of cosmopolitanism. Important idiosyncratic hydrophytes included Ceratophyllum, Chara, and Utricularia. Two of the three periphytic, rotifer datasets exhibited nestedness (T ¼ 19.2°, 39.9°), but each was supported by only one of the four null models. The periphytic microcrustaceans did not show nestedness, while the insects did (T ¼ 15.5°; supported by four null models). The three other metrics varied considerably among the periphytic datasets, showing no discernable pattern.

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Section: Methodsmentioning

confidence: 99%

Nestedness in sessile and periphytic rotifer communities: A meta‐analysis

Meksuwan

Pholpunthin

Walsh

et al. 2014

Internat. Rev. Hydrobiol.

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“…To perform the analyses, two matrices were constructed: the first matrix was ordered by columns according to the size gradient of the fragments, and the second matrix according to the isolation; then both were ordered by rows consistent with the occurrence or abundance of species (Atmar & Patterson, 1993;Lomolino, 1996;Ulrich et al, 2009). Thus, the force of the colonization and extinction processes in structuring the community was evaluated considering fragment size and isolation (Bruun & Moen, 2003;Cutler, 1994;Lomolino, 1996;Ulrich, 2009).…”

Section: Evaluation Of the Species Composition Nestednessmentioning

confidence: 99%

“…In this way, if area size produces nestedness and isolation does not, the system must be led by extinction because small patches have small population sizes, and colonization is therefore not sufficiently strong to generate nestedness. Under the opposite argument, that area size does not produce nestedness and isolation does, it is less clear whether it is selective immigration or extinction that determines the pattern (Bruun & Moen, 2003;Cutler, 1994;Lomolino, 1996;Ulrich, 2009;Ulrich & Gotelli, 2007), since local extinctions may actually be occurring but could be attenuated by a "rescue effect" from other fragments (Brown & Kodric-Brown, 1977). In this way, the dispersal capacity of the species has an effect, accumulating species with high and low dispersal in nearby patches and only species with high dispersal capacity in distant patches (Dornier & Cheptou, 2012;Leibold et al, 2004).…”

Section: Introductionmentioning

confidence: 99%

Consequences of swamp forest fragmentation on assemblages of vascular epiphytes and climbing plants: Evaluation of the metacommunity structure

Pincheira‐Ulbrich

Hernández

Saldaña

2018

Ecology and Evolution

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AimHabitat reduction in fragmented landscapes provides an opportunity to study the biogeographic patterns that drive changes in diversity in poorly studied metacommunities. In this study, colonization–extinction dynamics were indirectly evaluated through the analysis of the species–area relationship and the nestedness of vascular epiphytes and climbing plants in 30 swamp forest fragments.LocationCoast of the Araucanía Region in Chile.TaxonVascular epiphytes (16 species, mainly Pteridophytes) and climbing plants (15 species).MethodsWe used the database in Pincheira‐Ulbrich et al. (New Zealand Journal of Botany, 54, 2016, 458), where 904 trees were sampled and a total abundance of 41,097 fern fronds and 3,098 climbing stems were reported. For the species–area relationship, a simple linear regression model (SLR) and two models that consider the spatial autocorrelation of species richness among fragments, generalized least squares (GLS) and simultaneous autoregressive model (SAR), were compared. For the species nestedness, the nestedness measure based on overlap and decreasing fills (NODF) and weighted nestedness metric based on overlap and decreasing fill (WNODF) indexes were used on presence–absence and abundance matrices, respectively. These matrices were sorted by area size and distance from the largest fragment and then contrasted with the probability distribution of a randomized null model based on 10,000 simulations.ResultsThe results showed that the area size had a significantly positive effect on epiphyte species richness, while spatial autocorrelation played a fundamental role in explaining the richness of climbing plants. Both metacommunities had a general nestedness structure in terms of species incidence, which was determined first by area size and secondly by isolation.Main conclusionsOur results indicate that local colonization processes determined by species’ dispersal capacities could be the predominant mechanism for the spatial configuration of climbing plant species composition. On the other hand, selective extinction determined by patch size could characterize the spatial structure of epiphyte species’ composition.

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“…Second, we used gradient analyses, which consist of ordering the incidence matrix according to the site characteristic(s) of interests (e.g. area, distance) and comparing the degree of nestedness to identify the most dominant driver [48]. Computation of the three metrics was carried out using NODF-Program version 1.1 [49].…”

Section: Nestedness and Potential Determinantsmentioning

confidence: 99%

Forest-bird Species Assemblages in the Lowland Rainforest of Madagascar: The Effects of Forest Fragmentation Revisited

Rakotoarisoa¹

2013

TOCONSBJ

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Abstract:Although the eastern lowland rainforest of Madagascar houses a high proportion of endemic birds, little is known about how fragmentation effects and habitat loss specifically impact them. We analyzed published lists of forest birds across several eastern lowland rainforest fragments of three size classes (large: ~ 6,000 ha, medium: ~ 2,000 ha, small: ~ 600 ha) and varying distance (0.45-20 km) from a nearby continuous forest block. Several key species traits were incorporated to elucidate 1) patterns of species loss across forest fragments and the characteristics of lost species; 2) relationships of species richness and composition with fragment size and distance, and the factors that potentially drive these associations; and 3) pattern of nestedness in the resulting species assemblages. At the scale of our study, we found that species' vulnerability to loss was a function of degree of rarity and ecological specialization, such as insectivorous diet and habitat restriction. Fragment size was associated with species richness and composition. However, distance from the remaining continuous forest block and human disturbance, such as selective logging, may also influence their patterns of association. Both ecological factors and sampling effects (passive sampling of the regional species pool) appeared to influence species distribution across our fragments. Although no significant pattern of nested subset was detected among individual fragments, such a pattern is apparent among fragments from the three size classes. We briefly address conservation implications of these findings.

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Nestedness analysis as a tool to identify ecological gradients

Cited by 22 publications

References 38 publications

Nestedness in sessile and periphytic rotifer communities: A meta‐analysis

Nestedness in sessile and periphytic rotifer communities: A meta‐analysis

Consequences of swamp forest fragmentation on assemblages of vascular epiphytes and climbing plants: Evaluation of the metacommunity structure

Forest-bird Species Assemblages in the Lowland Rainforest of Madagascar: The Effects of Forest Fragmentation Revisited

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