The Meaning of z in Species/Area Regressions and the Study of Species Turnover in Island Biogeography

Oikos ◽  
1983 ◽  
Vol 41 (3) ◽  
pp. 385 ◽  
Author(s):  
Ian Abbott
Science ◽  
1976 ◽  
Vol 194 (4265) ◽  
pp. 572-578 ◽  
Author(s):  
D. Simberloff

2016 ◽  
Vol 283 (1829) ◽  
pp. 20160102 ◽  
Author(s):  
Ryan A. Chisholm ◽  
Tak Fung ◽  
Deepthi Chimalakonda ◽  
James P. O'Dwyer

MacArthur and Wilson's theory of island biogeography predicts that island species richness should increase with island area. This prediction generally holds among large islands, but among small islands species richness often varies independently of island area, producing the so-called ‘small-island effect’ and an overall biphasic species–area relationship (SAR). Here, we develop a unified theory that explains the biphasic island SAR. Our theory's key postulate is that as island area increases, the total number of immigrants increases faster than niche diversity. A parsimonious mechanistic model approximating these processes reproduces a biphasic SAR and provides excellent fits to 100 archipelago datasets. In the light of our theory, the biphasic island SAR can be interpreted as arising from a transition from a niche-structured regime on small islands to a colonization–extinction balance regime on large islands. The first regime is characteristic of classic deterministic niche theories; the second regime is characteristic of stochastic theories including the theory of island biogeography and neutral theory. The data furthermore confirm our theory's key prediction that the transition between the two SAR regimes should occur at smaller areas, where immigration is stronger (i.e. for taxa that are better dispersers and for archipelagos that are less isolated).


2011 ◽  
Vol 57 (3) ◽  
pp. 207-211
Author(s):  
Yoni Gavish

In their rebuttal to my comment, Roll et al. (2011) defend their original conclusion, by questioning the theoretical framework on which I based my analysis. They stress the importance of the statistical prediction limits and the treatment of latitudinal location as a covariate. They also add an additional grid-cell-based analysis. Here, I claim that even if provincial species-area relationships (SPAR) are not parallel, they are still different. While relying on Roll et al.'s (2011) analyses, I show that for each taxon there is at least one other provincial SPAR that lies considerably above the Palaearctic SPAR, making Palaearctic countries less favorable to be identified as a global biodiversity hotspot. I further claim that prediction limits should not be used to answer the question in focus and that adding latitude as a covariate does not alter the results. Finally, I address the grid-cell analyses of Roll et al. (2011), claiming that Israel's diversity lies mainly in the species turnover between cells (i.e., β diversity) and not on the average species richness within cells (α diversity). Therefore I hold on to my former conclusion that at least for three taxa—birds, mammals, and reptiles—Israel is indeed a Palaearctic provincial hotspot.


2021 ◽  
Vol 43 (1) ◽  
Author(s):  
JAIRO PATIÑO ◽  
ALAIN VANDERPOORTEN

In the present review, we provide an updated account on the level of knowledge in island bryophyte biogeography. In the framework of the 50 most fundamental questions for present and future island biology research highlighted by Patiño et al. (2017), we summarize current knowledge in bryophyte island biogeography and outline main research avenues for the future in the field. We found that only about 50% of the key current questions in island biogeography have been addressed to some extent, at least once, in bryophytes. Even fundamental questions that have caught the attention of ecologists since more than one century, such as the species-area relationship, have only rarely been dealt with in bryophytes. The application of the Island Biogeography Theory therefore opens an avenue for research in bryology, and we discuss the most salient features, including species and community phylogenetics, biotic interactions, and invasion biology.


2021 ◽  
Vol 1 (1) ◽  
Author(s):  
Teng Yang ◽  
Leho Tedersoo ◽  
Xiao Fu ◽  
Chang Zhao ◽  
Xu Liu ◽  
...  

AbstractIsland biogeography theory (IBT) is one of the most fruitful paradigms in macroecology, positing positive species-area and negative species-isolation relationships for the distribution of organisms. Biotic interactions are also crucial for diversity maintenance on islands. In the context of a timberline tree species (Betula ermanii) as “virtual island”, we surveyed ectomycorrhizal (EcM) fungal diversity along a 430-m vertical gradient on the top of Changbai Mountain, China, sampling fine roots and neighboring soils of B. ermanii. Besides elevation, soil properties and plant functional traits, endophytic and saprotrophic fungal diversity were assessed as candidate predictors to construct integrative models. EcM fungal diversity decreased with increasing elevation, and exhibited positive diversity to diameter at breast height and negative diversity to distance from forest edge relationships in both roots and soils. Integrative models further showed that saprotrophic fungal diversity was the strongest predictor of EcM fungal diversity, directly enhancing EcM fungal diversity in roots and soils. Our study supports IBT as a basic framework to explain EcM fungal diversity. The diversity-begets-diversity hypothesis within the fungal kingdom is more predictive for EcM fungal diversity within the IBT framework, which reveals a tight association between saprotrophic and EcM fungal lineages in the timberline ecosystem.


The colonization of the Krakataus by resident land birds is re-examined in view of two additional good data points, 1951 and 1984-86, which were not available to MacArthur & Wilson (1967) in their seminal work on island biogeography. The bird data for all years were carefully assessed with respect to the explicit criteria needed for the calculation of rates of extinction, immigration and turnover; these parameters are defined and calculated. Calculated from data from the two most recent surveys, the equilibrium number of species ( S ) for Rakata, the largest island, is from 48 to 56 and for the archipelago as a whole from 44 to 58; the ranges reflect alternative assessments of the records. By fitting a colonization equation to data from all surveys, S for the archipelago is estimated as 36 species, and by a procedure attempting to account for cryptoturnover, 38 species. These estimates compare with 30 (MacArthur & Wilson 1967) and 40-45 (Mayr 1965). Thirty-seven species were present during 1984-86. The establishment of the secondary forest and closure of the canopy had the greatest effect on colonization parameters of resident land birds since 1883. Immigration and turnover peaked in the period 1908-21 and fell sharply over the next decade, when, in contrast, extinctions reached a peak. The species that have colonized the Krakataus are mostly wide-ranging species that are found in both Java and Sumatra and have wide ecological tolerances. The earlier colonists were open country, generalist species, but since forest formation there was an increase in the proportion that are true forest species and more specialist feeders; more recent colonists have been aerial predators and insect feeders. Analysis of the colonization data suggests that the first resident land birds colonized the Krakataus one or two decades after the 1883 eruption. The newly emergent island, Anak Krakatau, has provided early serai habitats for species that have been lost from the other islands of the archipelago because of ecological succession and consequently the island provides an ecological refuge, postponing the extinction of birds that depend on these open habitats. Anak Krakatau’s emergence and continued existence will reduce species turnover and delay the achievement of equilibrium on the archipelago.


2017 ◽  
Vol 149 (4) ◽  
pp. 491-503 ◽  
Author(s):  
Aaron J. Bell ◽  
Iain D. Phillips ◽  
Scott E. Nielsen ◽  
John R. Spence

AbstractWe tested the applicability of the “passive sampling” hypothesis and theory of island biogeography (TIB) for explaining the diversity of forest-dwelling carabid assemblages (Carabidae: Coleoptera) on 30 forested islands (0.2–980.7 ha) in Lac la Ronge and the adjacent mainland in Saskatchewan, Canada. Species richness per unit area increased with distance to mainland with diversity being highest on the most isolated islands. We detected neither a positive species-area relationship, nor significant differences in species richness among island size classes, or between islands and the mainland. Nonetheless, carabid assemblages distinctly differed on islands <1 ha in area and gradually approached the structure of mainland assemblages as island area increased. Small islands were characterised by abundant populations of small-bodied, winged species and few if any large-bodied, flightless species like Carabus taedatus Fabricius. Our findings suggest that neither the “passive sampling” hypothesis nor the theory of island biogeography adequately explain carabid beetle diversity patterns observed among islands in Lac la Ronge. Instead, we hypothesise that population processes such as higher extinction rates of large-bodied, flightless species and the associated release of smaller-bodied, flying species from intra-guild predation on small islands contribute to observed differences in the structure of carabid assemblages between islands.


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