scholarly journals Calling for a new strategy to measure environmental (habitat) diversity in Island Biogeography: a case study of Mediterranean tenebrionids (Coleoptera: Tenebrionidae)

2015 ◽  
Vol 47 (1) ◽  
pp. 1 ◽  
Author(s):  
Simone Fattorini ◽  
Leonardo Dapporto ◽  
Giovanni Strona ◽  
Paulo A.V. Borges
Keyword(s):  
Species Richness ◽  
Land Cover ◽  
Island Biogeography ◽  
Environmental Heterogeneity ◽  
Habitat Diversity ◽  
Central Mediterranean ◽  
Environmental Diversity ◽  
New Strategy ◽  
Per Se

Many recent researches in island biogeography attempted to disentangle the effects of area <em>per se</em> and “habitat diversity” on species richness. However, the expression “habitat diversity” in this context should be avoided, because habitats can be only recognized by referring to the resources needed by a particular species. What is really measured in such researches is some form of “environmental heterogeneity”. Although habitat heterogeneity can be measured in various ways, most researches in island biogeography simply used the number of biotopes (typically classified as land cover categories). However, not all biotopes have the same surface. On the basis of the area occupied by each land cover category, it is possible to calculate indices of environmental diversity, evenness and dominance, as commonly done in community ecology research. These indices can be used to investigate the role of environmental diversity in determining species richness. We used the tenebrionid beetles inhabiting twenty-five small islands around Sicily (Central Mediterranean) to illustrate these concepts. We found that both area per se and environmental heterogeneity contributed to determine species richness. Moreover, we found that the relationship between species richness and environmental homogeneity followed a power function model. This indicates that environmental homogenization may determine a rapid, non linear decline in species richness.

scholarly journals Altitudinal diversity gradients and the theory of island biogeography - an explanation

2002 ◽  
Vol 8 (3) ◽  
pp. 213
Author(s):  
John Ogden
Keyword(s):  
Species Richness ◽  
New Zealand ◽  
Environmental Variables ◽  
Island Biogeography ◽  
Environmental Heterogeneity ◽  
Causal Agent ◽  
Forest Diversity ◽  
Island Biogeography Theory ◽  
Diversity Gradients ◽  
Theory Of Island Biogeography

As part of a wider discussion of forest diversity in New Zealand, Ogden (1995) pointed out that the area available between any pair of contours on a conical mountain decreased with altitude in parallel with the decrease in species richness. This correlation is confounded with other environmental variables, such as temperature, which have been widely considered to be causal in the diversity decline. However, generalization has been elusive, and the supposed causal mechanisms are often couched in vague terms such as "harshness". Ogden chose to emphasize area, and invoked the theory of island biogeography of MacArthur and Wilson (1967) by drawing parallels between islands and successively superimposed areas on mountains. Kingston (this issue) objected, mainly on the grounds that the theory of island biogeography refers to "isolated" areas and deals with the equilibrium between immigration and extinction, on which Ogden presented no evidence. In the light of these criticisms the data presented in Ogden (1995) is re-assessed here. I conclude that the "area hypothesis" is at least as good as any other for "explaining" (correlating with) elevational diversity trends. Area is itself correlated with environmental heterogeneity, which is presumably more important as a causal agent. However, Kingston's insistence on the need for evidence on immigration and extinction to support the application of island biogeography theory is acknowledged.

scholarly journals Evaluating the correlation between area, environmental heterogeneity, and species richness using terrestrial isopods (Oniscidea) from the Pontine Islands (West Mediterranean)

2021 ◽  
Author(s):  
Gabriele Gentile ◽  
Roberto Argano ◽  
Stefano Taiti
Keyword(s):  
Species Richness ◽  
Environmental Heterogeneity ◽  
Geographic Distance ◽  
Habitat Diversity ◽  
Tyrrhenian Sea ◽  
Island Species ◽  
Random Placement ◽  
Species Area ◽  
Pontine Islands ◽  
Volcanic Islands

AbstractArea and environmental heterogeneity influence species richness in islands. Whether area or environmental heterogeneity is more relevant in determining species richness is a central issue in island biogeography. Several models have been proposed, addressing the issue, and they can be reconducted to three main hypotheses developed to explain the species-area relationship: (1) the area-per se hypothesis (known also as the extinction-colonisation equilibrium), (2) the random placement (passive sampling), and the (3) environmental heterogeneity (habitat diversity). In this paper, considering also the possible influence of geographic distance on island species richness, we explore the correlation between area, environmental heterogeneity, and species richness by using faunistic data of Oniscidea inhabiting the Pontine Islands, a group of five small volcanic islands and several islets in the Tyrrhenian Sea, located about 60 km from the Italian mainland. We found that the colonisation of large Pontine Islands may occur via processes independent of geographic distance which could instead be an important factor at a much smaller scale. Such processes may be driven by a combination of anthropogenic influences and natural events. Even in very small-size island systems, environmental heterogeneity mostly contributes to species richness. Environmental heterogeneity could influence the taxocenosis structure and, ultimately, the number of species of Oniscidea via direct and indirect effects, these last mediated by area which may or may not have a direct effect on species richness.

scholarly journals Contemporizing island biogeography theory with anthropogenic drivers of species richness

2021 ◽  
Author(s):  
Jason Gleditsch ◽  
Jocelyn Behm ◽  
Jacintha Ellers ◽  
Wendy Jesse ◽  
Matthew Helmus
Keyword(s):  
Species Richness ◽  
Island Biogeography ◽  
Natural Habitat ◽  
Habitat Diversity ◽  
Positive Relationships ◽  
Relationship Expectations ◽  
Economic Area ◽  
Total Species Richness ◽  
Negative Relationships ◽  
Total Species

Classic ecological theory must explain effects of humans on biodiversity to be more applicable today. We contemporized island biogeographic theory providing native, introduced, and total species richness relationship expectations with natural and anthropogenic metrics of habitat diversity (geographic and economic area) and isolation from source pools (geographic and economic isolation). We assessed these expectations across Caribbean island herpetofauna clades. As expected by the contemporized theory, natural habitat diversity metrics exhibited positive relationships with native and introduced richness, strengthening positive total richness-area relationships. Geographic isolation exhibited negative relationships with native and positive relationships with introduced richness, weakening total richness-isolation relationships. Economic area and isolation exhibited negative and positive relationships, respectively, with native richness but positive and negative relationships, respectively, with introduced richness. Total richness relationships with economic area and isolation were strongest in clades with many introductions. As more species spread globally, these contemporary expectations will increasingly predict Anthropocene island biogeography.

scholarly journals Urbanization and species-energy relationships

2018 ◽  
Author(s):  
Lucas M. Leveau
Keyword(s):  
Species Richness ◽  
Primary Productivity ◽  
Positive Relationship ◽  
Environmental Heterogeneity ◽  
Negative Relationship ◽  
Habitat Diversity ◽  
Bird Abundance ◽  
Bird Richness ◽  
Urban Rural ◽  
Energy Relationships

AbstractSpecies-energy relationships (SER) have been used scarcely to predict responses of biodiversity to changes in land use. In this work, two hypothesis of the SER were tested on bird communities along urbanization gradients: the increasing population size (IPS) and the niche position (NP) hypotheses. The IPS hypothesis states that sites with more primary productivity have more individuals, decreasing the probability of extinction and increasing species richness. The HPN predicts that sites with greater primary productivity and environmental heterogeneity allow the availability of a greater variety of resources and the presence of specialist species, thus increasing species richness. The hypothesis of habitat heterogeneity was evaluated by which more complex habitats provide more variety of resources and greater species richness. Birds were counted along three urban-rural gradients in the Pampean region of Argentina during the breeding season. The productive energy was measured from the NDVI and the environmental heterogeneity through the Shannon-Wiener diversity index, calculated with the percentage coverage of different substrates. Bird richness and habitat diversity were higher at intermediate levels of urbanization, while primary productivity had a negative relationship with urbanization. Although there was a positive relationship between bird richness and abundance, there was no positive relationship between bird abundance and primary productivity. Bird richness showed a positive relationship with habitat diversity and primary productivity; although path analysis revealed that the habitat diversity increased bird richness through an increase of bird abundance. The NP hypothesis was the most consistent to predict the bird richness along urban-rural gradients.

scholarly journals From Island Biogeography to Conservation: A Multi-Taxon and Multi-Taxonomic Rank Approach in the Tuscan Archipelago

Land ◽  
2021 ◽  
Vol 10 (5) ◽  
pp. 486
Author(s):  
Enrico Ruzzier ◽  
Leonardo Forbicioni ◽  
Rodolfo Gentili ◽  
Nicola Tormen ◽  
Olivia Dondina ◽  
...  
Keyword(s):  
Species Richness ◽  
Differential Effect ◽  
Island Biogeography ◽  
Regression Models ◽  
Habitat Diversity ◽  
Land Bridge ◽  
Taxonomic Rank ◽  
Island Area ◽  
Species Area ◽  
Species Area Relationship

Investigating the drivers that support species richness (S) in insular contexts can give insights for the conservation of insular biodiversity. Our aim was to decouple the effect of drivers (island area, distance from mainland and habitat diversity) accounted in three hypotheses or a combination of them in explaining S in seven islands of the Tuscan Archipelago: Area (species–area relationship, SAR), area and distance from mainland (equilibrium hypothesis, EQH) and habitat (habitat diversity hypothesis, HDH). We used published and original datasets to assess S (except aliens) for 42 taxa (14 animal and 28 plant taxa) in each island, and we used S as the dependent variable and the drivers as covariates in regression models. In 31 taxa, the data supported one of the tested hypotheses or a combination of them, and the most commonly supported hypotheses were SAR (12 taxa) and EQH (10 taxa). The effect of the area was also evident in SAR + HDH (five taxa) and EQH + HDH (one taxon), making it the prevailing driver in explaining S. Since distances are relatively short, and three out of four islands are land-bridge islands, the effect of distance was significant for 12 taxa. The effects of habitat diversity were evident for just nine taxa. The multi-taxon approach allowed us to understand the differential effect of drivers among taxa in influencing S in a single archipelago. Moreover, the multi-taxonomic rank approach highlighted how the information contained within higher taxonomic ranks (e.g., Division) can be substantially different from that derived from lower ranks (e.g., Family). These insights are of particular importance from a conservation perspective of the archipelago’s biodiversity, and this approach can be transferred to mainland fragmented systems.

Parliament as the Foreign Policy Actor: the Resources of the Parliamentary Diplomacy

2018 ◽  
Vol 42 ◽  
pp. 316-321
Author(s):  
Boris I. Ananyev ◽  
Daniil A. Parenkov
Keyword(s):  
Foreign Policy ◽  
International Security ◽  
New Technologies ◽  
Conservative Approach ◽  
National Interests ◽  
Policy Actor ◽  
Security Challenges ◽  
Essential Idea ◽  
Per Se

The aim of the article is to show the role of parliament in the foreign policy within the framework of the conservative school of thought. The authors examine both Russian and Western traditions of conservatism and come to the conclusion that the essential idea of “the rule of the best” has turned to be one of the basic elements of the modern legislative body per se. What’s more, parliament, according to the conservative approach, tends to be the institution that represents the real spirit of the nation and national interests. Therefore the interaction of parliaments on the international arena appears to be the form of the organic communication between nations. Parliamentary diplomacy today is the tool that has the potential to address to the number of issues that are difficult to deal with within the framework of the traditional forms of IR: international security, challenges posed by new technologies, international sanctions and other.

Gedanken zu Genesis 46,8–27

2019 ◽  
Vol 63 (1) ◽  
pp. 93-104
Author(s):  
Wilfried Warning
Keyword(s):  
Close Reading ◽  
Per Se ◽  
Distinct Distribution

Abstract In general, commentators consider Gen 46:8–27 as a secondary addition. Close reading brings to light the structuring role of verses 18 and 25 („these were the sons of Zilpah / Bilhah … and these she bore to Jacob, sixteen souls / seven souls”). In a ten-part outline based on the personal name (PN) „Jacob” v. 18 takes the fourth and v.25 the fourth from last positions. In Genesis 37–50 the noun נפש „soul” occurs thirteen times – now v. 18 takes the sixth and v. 25 the sixth-from-last positions. The thirteen-part table based on the PN „Ruben” stands out for two reasons: Firstly, in Genesis the term „Ruben the first born of Jacob” shows up only twice, namely in the first (34,23) and last (46,8) texts. Secondly, as regards content 37,22 and 42,22 are correlated. In the 13-part outline they take the sixth and sixth-from-last positions respectively. The distinct distribution of these terms indicates that the passage per se is well structured and, what is more, at the same time it has been skillfully integrated in Gen 37–50 and in the Jacob-Joseph cycle.

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