Resurveyed Island Vegetation Reveals That Species Colonisation and Extinction Probabilities Are Linked to Traits

The equilibrium theory of island biogeography (ETIB) is a widely applied dynamic theory proposed in the 1960s to explain why islands have coherent differences in species richness. The development of the ETIB was temporarily challenged in the 1970s by the alternative static theory of ecological impoverishment (TEI). The TEI suggests that the number of species on an island is determined by its number of habitats or niches but, with no clear evidence relating species richness to the number of niches however, the TEI has been almost dismissed as a theory in favour of the original ETIB. Here, we show that the number of climatic niches on islands is an important predictor of the species richness of plants, herpetofauna and land birds. We therefore propose a model called the niche-based theory of island biogeography (NTIB), based on the MacroEcological Theory on the Arrangement of Life (METAL), which successfully integrates the number of niches sensu Hutchinson into ETIB. To account for greater species turnover at the beginning of colonisation, we include higher initial extinction rates. When we test our NTIB for resident land birds in the Krakatau Islands, it reveals a good correspondence with observed species richness, immigration and extinction rates. Provided the environmental regime remains unchanged, we estimate that the current species richness at equilibrium is ~45 species (range between 38.39 and 61.51). Our NTIB provides better prediction because it counts for changes in species richness with latitude, which is not considered in any theory of island biogeography.

In Memoriam : Edward O. Wilson (1929-2021): It All Started with Ants.

8.1 INTRODUCTION When a nature preserve is set aside, it is destined to become an island in a sea of habitats modifi ed by man. (Wilson & Willis, 1975 , 525) p. Islands have played a central part in the development of conservation theory. In particular, the Equilibrium Theory of Island Biogeography (ETIB) (MacArthur & Wilson, 1963, 1967 ; Wilson, 1969 ) has played a pivotal role in diverse areas such as protected area network design theory and predicting extinction rates. The ETIB is a dynamic equilibrium model which pos-tulates that the number of species of a given taxon found on an island will be the product of opposing forces leading respectively to the gain and loss of species, and resulting in a continual turnover of the species present on each island through time. This is captured in MacArthur and Wilson ’ s famous graphical model, in which immigration rate declines exponentially and extinction rate rises exponentially as an initially empty island fi lls up towards its equilibrium richness value (shown by the intersection; Figure 8.1 ). The immigration rate curve fl attens with increasing island isolation and the extinction rate curve fl attens with increasing area, thereby generating a family of curves providing unique combinations of richness and turnover for each combination of area and isolation. The infl uence of the ETIB is marked not just by the research it has inspired, but also by the theories and applications it has spawned and infl uenced (e.g. species – energy theory, metapopulation theory, island assembly theory, neutral theory and stochastic niche theory; reviewed in Whittaker & Fenr a ndez - Palacios, 2007 ). Within a few years of publication, the applica-tion of the ETIB to the fi eld of conservation was being vigorously debated by academics. One of the key insights was the realization that terrestrial reserves and national parks could be viewed as simply another type of island ( ‘ habitat islands ’ ) surrounded by a ‘ sea ’ of human - altered landscapes. It logically followed that these reserves would behave like islands cut off from the mainland by rising sea levels, i.e. they would lose species as they ‘ relaxed towards equilibrium ’ (Figure 8.1 ; Diamond, 1975a ; Wilson & Willis, 1975 ). In the context of the ‘ crisis ’ discourse of conserva-tion science from the 1970s onwards, several pro-minent conservation scientists turned to island theory in the search for an ‘ off the shelf ’ general scientifi c guide on protected area system design to assist in both advocacy and implementation. If each protected area might become, in time, an island surrounded by habi-tats modifi ed by man (Wilson & Willis, 1975 , p. 18), and given a fi nite total area that can be set aside for conservation as a natural landscape is being converted to other uses, one of the basic questions is, ‘ What confi guration of reserves should conservationists advocate? ’ According to Margules & Pressey (2000) , reserves have two main roles: they should sample or represent the biodiversity of each region and they should

Changes in the amount and timing of precipitation may affect plant species coexistence. However, little is known about how these changes in precipitation structure plant communities. Here, we conducted a 6-year field precipitation manipulation experiment in the semi-arid steppe of Inner Mongolia, China, to assess the importance of species extinction and colonization in community assembly by incorporating information on phylogenetic and functional relatedness. Our results demonstrated that the decline in plant species richness under decreasing precipitation in the late and entire growing season could be attributed to a decrease in species colonization and an increase in species loss, respectively. The increase in species richness under increasing precipitation in the late growing season was mainly caused by increases in colonizing species. The loss of species that were more closely related to other residents under decreasing precipitation in the late growing season did not alter patterns of phylogenetic overdispersion, and the colonization of species that were more distantly related to residents under increasing precipitation in the late growing season shifted functional relatedness from clustering to randomness. Increasing precipitation may weaken the strength of environmental filtering induced by water stress in this semi-arid steppe and thus increase the probability of successful colonization of functionally dissimilar species relative to residents. Our study suggests that incorporating information on the functional and phylogenetic relatedness of locally lost resident species and the colonization of new species into analyses of community assembly processes can provide new insights into the general responses of plant communities to global change.

Mosquitoes are well known for their epidemiological importance as vectors of a wide range of human pathogens. Despite the many studies on medically important species, little is known about the diversity patterns of these insects in urban green spaces, which serve as shelter and refuge for many native and invasive species. Here, we investigate drivers of mosquito richness and composition in nine urban parks in the city of São Paulo, Brazil. Using the equilibrium theory of island biogeography, we tested predictive models for species richness and composition and performed nestedness analysis. We also investigated whether species loss tends to benefit vector mosquitoes. In the period 2011 to 2013, a total of 37,972 mosquitoes belonging to 73 species and 14 genera were collected. Our results suggest there is a species-area relationship, an increase in species similarity as richness is lost and a nested species composition pattern. Seven of the eight most commonly found species are considered vectors of human pathogens, suggesting a possible link between species loss and increased risk of pathogen transmission. Our data highlight the need for studies that seek to understand how species loss may affect the risk of infectious diseases in urban areas.

We are delighted to publish the first collection of papers submitted in response to the announcement of the Journal of Biogeography (JBI) Innovation Awards. These manuscripts were considered using JBI's standard editorial and peer review processes, and were additionally ranked in terms of the originality of their ideas, identification of a gap in knowledge, impact of findings and quality of preparation of the manuscript at each round of editorial review. The set published here are the top ranked among the submissions, and also hold their own among the novel, insightful, consequential and well-prepared manuscripts submitted year-round to JBI. The papers address a range of topics within biogeography's broad remit, the focal taxa represent divergent lineages of eukaryotes and other organisms with which they interact, and the research or teams span continents. We congratulate William Carvalho, Thais Vasconcelos and Frederic Windsor as the inaugural recipients of the Journal of

Effect of Environmental Factors on the Colonization of Surfaces by Pseudomonas Fluorescens

Fungal colonization of resources in soil — An island biogeographical approach

SUMMARYBecause of their isolation, biotic communities of urban green spaces are expected to be similar to those of oceanic islands. This should be particularly true for insects, which represent an important component of urban faunas. The equilibrium theory of island biogeography (ETIB) allows for the formulation of some hypotheses regarding the influence of the geographical characteristics of green spaces on insect species richness and extinction risk. Based on island biogeography principles, we present eight predictions on how green space characteristics should influence insect species richness and loss. We analysed the current literature in order to determine which predictions were supported and which were not. We found that many studies gave outcomes that support ETIB predictions about the effects of area and isolation of green spaces; we found no strong support for predictions about shape and extent of native habitat in the literature that we reviewed. Most of the available studies dealt with patterns in species richness, whereas insect species loss has been rarely investigated. Future developments in the application of island biogeography principles to urban insect conservation should address temporal trends in species persistence and the analysis of species co-occurrence and nestedness.

The equilibrium theory of island biogeography proposes that on an island of a given area, there exists an equilibrium number of species when the rates of immigration and local extinction of species are equal (MacArthur and Wilson 1967). This theory has been applied to park systems because parks may act as functional islands when surrounding unprotected land is cleared of natural vegetation. Alteration of these surrounding habitats isolates these parks and reduces the effective area, causing a decrease in the equilibrium number of species. In animal communities, this process is called faunal collapse (Soule et al. 1979).The effects of park isolation and faunal collapse have been studied for mammals in Rocky Mountain parks (Picton 1979, Newmark 1986, Glenn and Nudds 1989). In western U.S. parks, extinctions were more numerous in smaller or older parks (Newmark 1987). Area, topographic diversity, and habitat diversity have been correlated with mammal species richness in western North American parks (Picton 1979, Newmark 1986). Initial population size was also related to the extinction probability of a species (Newmark 1986). It has been proposed that all parks in a region are subject to similar factors influencing local extinctions, and therefore a similar suite of species should become locally extinct in all parks (Patterson and Atmar 1986, Patterson 1987). This means that a nested subset pattern is produced, where parks with low species richness contain mainly species already present in parks with high species richness. This pattern was not found for Canadian parks, where even small parks contained different species assemblages (Glenn 1990). The objectives of this three-year study are to: (i) identify mammal species that have become locally extinct in each of the Rocky Mountain National Parks; (ii) distinguish between hypotheses regarding the causes of these local extinctions in National Parks; (iii) determine if the same species become locally extinct in all parks; and (iv) identify potential sites for future protection of species prone to extinction.

Aim We studied the relationship between the size and isolation of islands and bat species richness in a near‐shore archipelago to determine whether communities of vagile mammals conform to predictions of island biogeography theory. We compared patterns of species richness in two subarchipelagos to determine whether areaper seor differences in habitat diversity explain variations in bat species richness.Location Islands in the Gulf of California and adjacent coastal habitats on the Baja California peninsula in northwest Mexico.Methods Presence–absence surveys for bats were conducted on 32 islands in the Gulf of California using acoustic and mist‐net surveys. We sampled for bats in coastal habitats of four regions of the Baja peninsula to characterize the source pool of potential colonizing species. We fitted a semi‐log model of species richness and multiple linear regression and used Akaike information criterion model selection to assess the possible influence of log10area, isolation, and island group (two subarchipelagos) on the species richness of bats. We compared the species richness of bats on islands with greater vegetation densities in the southern gulf (n = 20) with that on drier islands with less vegetation in the northern gulf (n = 12) to investigate the relationship between habitat diversity and the species richness of bats.Results Twelve species of bats were detected on islands in the Gulf of California, and 15 species were detected in coastal habitats on the Baja peninsula. Bat species richness was related to both area and isolation of islands, and was higher in the southern subarchipelago, which has denser vegetation. Log10area was positively related to bat species richness, which increased by one species for every 5.4‐fold increase in island area. On average, richness declined by one species per 6.25 km increase in isolation from the Baja peninsula.Main conclusions Our results demonstrate that patterns of bat species richness in a near‐shore archipelago are consistent with patterns predicted by the equilibrium theory of island biogeography. Despite their vagility, bats may be more sensitive to moderate levels of isolation than previously expected in near‐shore archipelagos. Differences in vegetation and habitat xericity appear to be associated with richness of bat communities in this desert ecosystem. Although observed patterns of species richness were consistent with those predicted by the equilibrium theory, similar relationships between species richness and size and isolation of islands may arise from patch‐use decision making by individuals (optimal foraging strategies).

1. We test MacArthur and Wilson's theory about the biogeography of communities on isolated habitat patches using bird breeding records from 16 small islands off the coasts of Britain and Ireland. 2. A traditional examination of patterns of species richness on these islands suggests that area and habitat diversity are important predictors, but that isolation and latitude have a negligible impact in this system. 3. Unlike traditional studies, we directly examine the fundamental processes of colonization and local extinction (cessation of breeding), rather than higher-order phenomena such as species richness. 4. We find that many of MacArthur and Wilson's predictions hold: colonization probability is lower on more isolated islands, and extinction probability is lower on larger islands and those with a greater diversity of habitats. 5. We also find an unexpected pattern: extinction probability is much lower on more isolated islands. This is the strongest relationship in these data, and isolation is the best single predictor of colonization and extinction. 6. Our results show that examination of species richness alone is misleading. Isolation has a strong effect on both of the dynamic processes that underlie richness, and in this system, the reductions in both colonization and extinction probability seen on more distant islands have opposing influences on species richness, and largely cancel each other out. 7. We suggest that an appropriate model for this system might be optimal foraging theory, which predicts that organisms will stay longer in a resource patch if the distance to a neighbouring patch is large. If nest sites and food are the resources in this system, then optimal foraging theory predicts the pattern we observe. 8. We advance the hypothesis that there is a class of spatial systems, defined by their scale and by the taxon under consideration, at which decision-making processes are a key driver of the spatiotemporal dynamics. The appropriate theory for such systems will be a hybrid of concepts from biogeography/metapopulation theory and behavioural ecology.

Habitat fragmentation differentially affects invasive and native plant diversity in a human-dominated wetland island system

A generalization of the taxon cycle

Spatial processes that maintain biodiversity in plant communities