Does reaction-diffusion support the duality of fragmentation effect?

Does reaction-diffusion support the duality of fragmentation effect?

The effects of habitat fragmentation on plant–animal interactions may emerge at different spatial scales, depending on the species-specific perception response of the interacting animals. Furthermore, changes in habitat cover and configuration commonly occur simultaneously, hampering efforts to understand and mitigate the impact of fragmentation on these biotic interactions. In order to account for the relative influence of habitat loss and fragmentation on plant–animal interactions, we quantified habitat structure in sixteen sectors (nested circular areas of 100 and 200 m radii) in four different localities (four sectors per locality) across the Cantabrian Range in NW Spain. In the center of each 100 m radius sector, we measured the magnitude of two ecologically opposite (mutualistic vs antagonistic) interactions in individual holly trees Ilex aquifolium which strongly determine the regeneration process in this plant species: frugivory by birds and seed predation by rodents. We found that habitat fragmentation, though not habitat loss, affected the magnitude of both plant–animal interactions. However, these effects were conditioned by the strong differences in spatial heterogeneity in habitat structure between localities. In fact, the effect of habitat fragmentation on both plant–animal interactions disappeared when the locality in which sectors were sited was taken into account. This study highlights that 1) habitat spatial configuration, far from being a negligible component of habitat structure, is in fact able to influence key ecological processes such as plant–animal interactions, and 2) the potential spatial and structural complexity of localities makes a regional approach (i.e. that involving many localities) indispensable in the quest for comprehensive understanding of the effects of habitat structure on biodiversity in real-world fragmented landscapes.

The reliability of ants as bioindicators of ecosystem condition is dependent on the consistency of their response to localised habitat characteristics, which may be modified by larger-scale effects of habitat fragmentation and loss. We assessed the relative contribution of habitat fragmentation, habitat loss and within-patch habitat characteristics in determining ant assemblages in semi-arid woodland in Queensland, Australia. Species and functional group abundance were recorded using pitfall traps across 20 woodland patches in landscapes that exhibited a range of fragmentation states. Of fragmentation measures, changes in patch area and patch edge contrast exerted the greatest influence on species assemblages, after accounting for differences in habitat loss. However, 35% of fragmentation effects on species were confounded by the effects of habitat characteristics and habitat loss. Within-patch habitat characteristics explained more than twice the amount of species variation attributable to fragmentation and four times the variation explained by habitat loss. The study indicates that within-patch habitat characteristics are the predominant drivers of ant composition. We suggest that caution should be exercised in interpreting the independent effects of habitat fragmentation and loss on ant assemblages without jointly considering localised habitat attributes and associated joint effects.

We examined the literature on the effects of habitat fragmentation and disturbance on howler monkeys (genus Alouatta) to (1) identify different threats that may affect howlers in fragmented landscapes; (2) review specific predictions developed in fragmentation theory and (3) identify the empirical evidence supporting these predictions. Although howlers are known for their ability to persist in both conserved and disturbed conditions, we found evidence that they are negatively affected by high levels of habitat loss, fragmentation and degradation. Patch size appears to be the main factor constraining populations in fragmented habitats, probably because patch size is positively related to food availability, and negatively related to anthropogenic pressures, physiological stress and parasite loads. Patch isolation is not a strong predictor of either patch occupancy or population size in howlers, a result that may be related to the ability of howlers to move among forest patches. Thus, we propose that it is probable that habitat loss has larger consistent negative effects on howler populations than habitat fragmentation per se. In general, food availability decreases with patch size, not only due to habitat loss, but also because the density of big trees, plant species richness and howlers' home range size are lower in smaller patches, where howlers' population densities are commonly higher. However, it is unclear which vegetation attributes have the biggest influence on howler populations. Similarly, our knowledge is still limited concerning the effects of postfragmentation threats (e.g. hunting and logging) on howlers living in forest patches, and how several endogenous threats (e.g. genetic diversity, physiological stress, and parasitism) affect the distribution, population structure and persistence of howlers. More long-term studies with comparable methods are necessary to quantify some of the patterns discussed in this review, and determine through meta-analyses whether there are significant inter-specific differences in species' responses to habitat loss and fragmentation.

Habitat loss and habitat fragmentation usually occur together, at the same time and place. However, while there is a consensus that habitat loss is the preeminent threat to biodiversity, the effects of fragmentation are contentious. Some argue that habitat fragmentation is not bad for biodiversity, and even that it is good. Generally, the studies that find no harm or positive outcomes of fragmentation invariably assume that it is independent of habitat loss. However, dissociating the effects of habitat fragmentation from habitat loss is questionable because the two are essentially coupled. Accordingly, we evaluated how forest area and fragmentation (via edge effects) influenced dung beetles per se, and through their effects on the abundance of mammals, using structural equation modeling (SEM). Dung beetles are very sensitive to forest habitat loss and fragmentation and to changes in the abundance of mammals on which they depend for dung. Our study area was in the Tana River, Kenya, where forest fragments are depauperated of mammals except for two endemic species of monkeys. We mapped 12 forests, counted the resident monkeys, and sampled 113,955 beetles from 288 plots. Most of the 87 species of beetles found were small tunnellers. After implementing a fully latent Structural Regression SEM, the optimal model explained a significant 26% of the variance in abundance, and 89% of diversity. The main drivers of beetle abundance were positive, direct, effects of forest area and number of monkeys, and negative edge effects. The main drivers of diversity were the direct effects of the beetle abundance, indirect effects of forest area and abundance of mammals, and indirect negative edge effects. Thus, forest area, fragmentation (via edge effects), and the number of monkeys jointly influenced the abundance and diversity of the beetles directly and indirectly.

Primates are a particularly sensitive order to the negative effects of habitat loss and fragmentation due to their unique life histories and habitat requirements. Given that nearly all primate populations are in some way affected by habitat loss and fragmentation, it is important for all primatologists – even those uninterested in these processes directly – to consider the effects of habitat loss and fragmentation on the behavior and conservation of their study species. In this chapter, we review some of the current knowledge of the effects of habitat loss and fragmentation on primate behavior. We begin by defining key terms and discussing issues of scale. We then review some of the major literature regarding primary and secondary effects of fragmentation, highlighting its potential impact on home range, social interactions, and group composition. Finally, we note that primate responses to habitat fragmentation are species- and sometimes even site-specific and recommend a holistic approach for future research concerning habitat loss and fragmentation.

Anthropogenic habitat fragmentation has well-established deleterious effects on populations and communities of native vertebrates, but the mechanisms underlying population decline under fragmentation remain poorly understood. Most studies of vertebrates in anthropogenically-fragmented habitats have focused on population density, demographics or fecundity. Relatively little attention has been given to indices of health status, body condition or physiological stress. In this study, 30 populations of a small marsupial, the agile antechinus (Antechinus agilis), living in anthropogenically-fragmented forest patches were sampled in two years (2007 and 2008). Immediately after sampling in each fragment, a population in a matched control site in similar, but unfragmented forest (a 'pseudofragment') was sampled. Indices of population density (relative abundance), estimated fat reserves (mass-size residuals), health status (erythrocyte variables), parasite load (simplified ectoparasite counts and eosinophil percentages) and chronic physiological stress (total and differential immune cell counts) were examined. Relative abundances were lower and parasite load indices higher in fragmented than continuous forest. Fragment populations displayed indications of regenerative anaemia, which is related to poor health status and potentially caused by chronic stress, frequent blood loss or heavy parasite loads. Estimated fat reserves were higher in fragment than continuous forest populations. Nonetheless, differential leukocyte counts suggested that chronic physiological stress was greater (i.e. greater neutrophil-to-lymphocyte ratios) (N:L) in populations in fragments. Anthropogenic fragmentation effects are not often distinguished in the ecological literature from those of co-occurring processes, such as habitat loss and degradation. To investigate the effects of these processes, environmental factors were examined that were thought to have a potential influence on agile antechinus (e.g. fragment patch core area, proportion of edge habitat, isolation, woody debris abundance, shrub density etc). Relative abundance of agile antechinus was positively correlated with forest patch core area and native tree-cover within a 0.5 km radius of a study site. Estimated fat reserves, particularly in males, were greater in populations in fragments with a smaller core area, but statistical modelling indicated that the effect was an indirect one: males had greater estimated fat reserves where the abundance of conspecifics was lower, suggesting that this metric was responding to intraspecific competition and per capita food availability. Health status, indexed by erythrocyte indicators of regenerative anaemia,was positively associated with greater microhabitat heterogeneity, and abundance of shrubs, logs and native trees other than Eucalyptus species. Female abundances were lower in edge habitat (< 60 m from edge) than in fragment interiors (> 80 m from edge), and females had higher chronic stress indicators (N:L) where fragments were more highly dissected by edge habitat. Although parasite load indices and male N:L were higher in fragment than continuous forest sites, the environmental factors responsible were not identified. The study has demonstrated that anthropogenic habitat fragmentation, loss and degradation can have broadly negative effects on a native vertebrate, not only on its population density, but also in terms of health status and chronic physiological stress. This is a serious concern from a conservation management perspective, because chronic stress has pronounced fitness-reducing effects in vertebrates, including reduced reproductive investment, fecundity and survivorship.

Habitat loss and fragmentation are widely believed to be the most important drivers of extinction (Leakey and Lewin 1995). The habitats in which organisms live are spatially structured at a number of scales, and these patterns interact with organism perception and behavior to drive population dynamics and community structure (Johnson et al. 1992). Anthropogenic habitat loss and fragmentation disrupts these patterns and is expected to have large, negative effects on biodiversity (Flather and Bevers 2002; Haila 2002; Fahrig 2003). The majority of theoretical studies suggest that the effect of habitat fragmentation is weak relative to the effect of habitat loss (Fahrig 1997; Henein et al. 1998; Collingham and Huntley 2000; Flather and Bevers 2002; Fahrig 2003), although some studies have predicted larger fragmentation effects (Boswell et al. 1998; Burkey 1999; Hill and Caswell 1999; Urban and Keitt 2001). In addition, some theoretical studies suggest that the effects of fragmentation per se should become apparent only at low levels of habitat amount, for example below approximately 20–30% of the landscape (Fahrig 1998; Flather and Bevers 2002), although there is little empirical evidence available to test this prediction (Fahrig 2003).

Aim Habitat loss and fragmentation are amongst the greatest threats to biodiversity world‐wide. However, there is still little evidence on the relative influence of these two distinct processes on biodiversity, and no study, to date, has investigated the independent contribution of structural connectivity in addition to habitat loss and fragmentation. The aim of this study is to evaluate the independent effects of habitat loss (the decrease in total amount of habitat), habitat fragmentation per se (habitat subdivision) and structural connectivity (in the form of hedgerow networks) on the distribution of seven resident forest‐dependent birds in central Italy.Location Central Italy.Methods We strategically selected 30 landscapes (each of 16 km2 in size) with decreasing total amount of forest cover and with contrasting configuration of patches and contrasting lengths of hedgerow networks. Presence/absence of birds in each landscape unit was studied through point counts.Results The amount of forest cover in the landscape had the strongest relative influence on birds’ occupancy, whilst habitat subdivision played a negligible role. Structural connectivity and the geographic position of the landscape unit played a relatively important role for four species.Main conclusions Our study shows the importance of disentangling the contribution of different landscape properties in determining distribution patterns. Our results are consistent with the fact that halting habitat loss and carrying out habitat restoration should be conservation priorities, since habitat loss is the main factor affecting the distribution of the target species; implementation of structural connectivity through hedgerows, instead, should be evaluated with caution since its contribution is secondary to the predominant role of habitat loss.

Non-linear effect of habitat fragmentation on plant diversity: Evidence from a sand dune field in a desertified grassland in northeastern China

Habitat loss and fragmentation has long been considered the primary cause for biodiversity loss and ecosystem degradation worldwide, and is a key research topic in landscape ecology (Wu 2013). Habitat fragmentation often refers to the reduction of continuous tracts of habitat to smaller, spatially distinct remnant patches, and habitat loss typically occurs concurrently with habitat fragmentation (Collinge 2009). Although some habitats are naturally patchy in terms of abiotic and biotic conditions (Wu and Loucks 1995), human actions have profoundly fragmented landscapes across the word (Haddad et al. 2015), altering the quality and connectivity of habitats. Therefore, understanding the causes and consequences of habitat fragmentation is critical to preserving biodiversity and ecosystem functioning. From May 4th to 10th, 2015, an International Workshop on Habitat Fragmentation and Biodiversity Conservation, held at the Thousand Island Lake, Zhejiang, China, discussed threats to biodiversity in fragmented landscapes and how fragmentation research can identify and help mitigate these threats. To meet these challenges, the Workshop had three goals. The first was to synthesize key findings in fragmentation science. Second was to identify important remaining research questions concerning the relationships between habitat fragmentation, biodiversity, and ecosystem functioning at local, regional, and global scales. Finally, we examined the unique roles of field-based fragmentation experiments in addressing these questions. The Workshop’s findings are relevant to the broader ecological community, and we present them here to stimulate research that will advance landscape ecology and conservation biology.

The Serengeti wildebeest migration is a rare and spectacular example of a once-common biological phenomenon. A proposed road project threatens to bisect the Serengeti ecosystem and its integrity. The precautionary principle dictates that we consider the possible consequences of a road completely disrupting the migration. We used an existing spatially-explicit simulation model of wildebeest movement and population dynamics to explore how placing a barrier to migration across the proposed route (thus creating two disjoint but mobile subpopulations) might affect the long-term size of the wildebeest population. Our simulation results suggest that a barrier to migration—even without causing habitat loss—could cause the wildebeest population to decline by about a third. The driver of this decline is the effect of habitat fragmentation (even without habitat loss) on the ability of wildebeest to effectively track temporal shifts in high-quality forage resources across the landscape. Given the important role of the wildebeest migration for a number of key ecological processes, these findings have potentially important ramifications for ecosystem biodiversity, structure, and function in the Serengeti.

This is my second Editorial since I became Editor-in-Chief of the African Journal of Ecology (AJE). As I did with my previous Editorial (Luiselli, 2023), I will continue in this case (and in the case of future Editorials) to emphasise the aspects of African ecology that, in my opinion, are still underdeveloped and the role that AJE can play in their development. In the previous Editorial (Luiselli, 2023), I addressed the general "themes" of greatest importance for the development of a fully "modern" ecological science in Africa. Starting from this "Editorial" I will deal with more specific "hot" topics that will be of particular interest to our journal over the next few years. For each of these "hot" topics, I will invite specific contributions from prominent authors in the form of "Reviews", "Perspectives", and "Interdisciplinary Perspectives", and I will even explore the potential for having special issues dedicated to them. I'm going to start this series of more specific contributions with addressing one of the hottest topics in contemporary conservation ecology: the habitat fragmentation. Habitat fragmentation is widely acclaimed as one of the main threats to biodiversity (Fahrig, 2017, 2019). Over the last two decades, literally rivers of (scientific) ink have been poured in the "northern world" (Europe and North America) to describe the importance of matrix permeability to allow animals to cross between forest patches (e.g., Anderson et al., 2022; Erős & Campbell Grant, 2015; Luque et al., 2012; Neuschulz et al., 2013; Watts & Handley, 2010). As a result, a dynamic theory around the phenomenon of habitat fragmentation has rapidly developed as well as how to maintain valid ecological connectivity between fragments. Analytical software has also been created to assess the resistance of fragment matrices and other parameters of management interest (e.g., Fardila et al., 2017; Leonard et al., 2017). A unifying point of several of these studies is that the matrix is the functionally dominant unit of the landscape (Forman & Godron, 1986). In Africa, habitat fragmentation is not less a threat to biodiversity than in temperate regions, particularly for forest species (e.g., Bloomfield et al., 2020; Curry et al., 2021; Davis & Philips, 2005; Dendi et al., 2023; Newmark & McNeally, 2018). For example, the Guinean forests of West Africa are considered among the most fragmented forest habitats in the world, a biodiversity hotspot, currently comprising no more than 5%–10% of its original extension. Habitat fragmentation processes in Africa are also characterised by dynamics that are almost unknown in other continents. For instance, Africa contains the largest number of refugees in the world (about 34% of the total), and there is a massive agricultural expansion and habitat loss in refugee-hosting areas (for instance, in some areas of Uganda) (Maystadt et al., 2020). The "refugee-induced" habitat fragmentation effect has remained virtually scientifically unstudied but is certainly a very promising field of investigation in the years to come. A "Google Scholar" search (12 December 2022) revealed that there are very few articles focusing on Africa on: (i) ecological connectivity between forest patches, sacred grooves, and protected reserves (e.g., Alohou et al., 2017; Smith et al., 2019) or (ii) modelling the distribution of threatened faunas in relation to the spatial distribution and the connectivity of the forested patches (Freeman et al., 2019). It seems evident to me that the issue of how to recreate invaluable ecological connectivity between isolated forest patches (or well-preserved savannahs) is currently rather forgotten in the African ecological literature, albeit being extremely important. Instead, the emphasis is virtually always on protected areas (the "core") and the management of faunas within these core habitats. However, recent work in the Dahomey Gap, West Africa, suggests that the management of the altered "matrix" is as important as maintaining forest patches in a savannah-forest mosaic landscape. This is because it is essential to allow many mammal species to be able to move between patches during certain seasons (Matshisela et al., 2021; Segniagbeto et al., 2022). Moreover, such matrix studies are also important for the development of community-controlled hunting areas that can enhance the conservation value of well-preserved buffer zones (Atsri et al., 2020), together with promoting sustainable agricultural production systems in degraded areas. Such an approach can help stabilise the agricultural front and reduce land pressure on the forests themselves (Atsri et al., 2020). Scrolling down recent contents of AJE, we can notice that we published many excellent articles that were directly or indirectly important for addressing aspects of habitat loss and fragmentation, but with a clear substantial attention to the "core" and not to "what surrounds it" (the matrix). For instance, we published several demographic studies and other interesting observations/data focusing on wildlife species within protected pristine areas (e.g., Amin et al., 2022; Gush et al., 2022; Lee et al., 2023; Meheretu et al., 2022; Sonhaye-Ouyé et al., 2022; Turikunkiko et al., 2022; Uwizelimana et al., 2022), whereas those focusing on the matrix areas surrounding pristine protected areas were much less (Kifle & Bekele, 2022; Kisingo et al., 2021; Ncube & Tarakini, 2022). Changing the paradigm, i.e., shifting at least partially the focus away from core areas as biodiversity hotspots to the surrounding matrix, could constitute a great opportunity for conservation (and for ecological research as well). In fact, it will bring to the fore also the 'minor' environmental mosaics, often underestimated and ignored but ecologically relevant both structurally (as habitat for biodiversity), and functionally (as role in species dispersal; Poiani et al., 2000). For instance, the fragmented island forests of Africa and their surroundings will become promising field scenarios for ecological research (e.g., see Segniagbeto et al., 2022). Core areas are undoubtedly a priority as they not free from human threats, although most are protected to some degree. Nevertheless, focusing research and conservation efforts only on them can be a serious mistake, since distracting oneself from what is happening in the surrounding landscape matrices means starting a progressive isolation of the core areas and interrupting fundamental connective processes (Salerno et al., 2018; Segniagbeto et al., 2022). 'Tunnel vision' and 'functional cognitive fixedness' must be overcome (Ward et al., 2019). Cognitive biases (i.e., the systematic pattern of deviation from rationality in judgement and perception; Barnes, 1984) can influence decisions also in nature conservation (Catalano et al., 2018). In this sense, it is important that conservation managers do not automatically anchor themselves only to hotspots following charismatic perceptions (an 'anchoring bias'; Cinner, 2018) and initiate a change of vision by focusing on still neglected landscape matrices. Therefore, I am inviting potential contributors to submit to AJE original articles or reviews and meta-analysis on the phenomenon of habitat fragmentation and the role of matrix management for the conservation of animals and plants in Africa. I would seek especially those studies documenting the field data into a theoretical framework that, as for the African studies, has never been properly and deeply analysed. This article has been improved through constructive discussions with Dr C. Battisti (Rome), Dr M. Behangana (Kampala), Prof. G.H. Segniagbeto (Lomé), and Prof. J.E. Fa (Manchester).

Kin structure, the spatial aggregation of related individuals, impacts many processes important to conservation (e.g. inbreeding), and patterns of kin structure could be impacted by human‐mediated habitat fragmentation and loss. While kin structure is expected to increase with habitat fragmentation (reduced connectivity), the effects of habitat loss (reduced resource availability) remain unclear. Disentangling the effects of habitat fragmentation and loss is challenging because they usually are spatially correlated, and because most species are negatively affected by both processes. Raccoons Procyon lotor is a model species to test how habitat loss affects kin structure because, although relatively unaffected by habitat fragmentation (because of high dispersal ability), they are negatively affected by habitat loss (forest‐related resources being important for female reproductive success). To elucidate the causes and consequences of kin structure in raccoons, we utilized genetic and demographic data collected from 998 individuals trapped from 27 spatially distinct habitat patches (local populations) situated in an agricultural ecosystem. Our results highlight an important, but often ignored fact: structural connectivity does not necessarily predict functional dispersal patterns in natural populations. Thus, in raccoons, local populations with low kin structure were associated with high landscape disturbance (i.e. high levels of habitat loss and low connectivity), and were characterized by demographic instability (i.e. high immigration, emigration and/or mortality). Alternatively, local populations exhibiting high kin structure were associated with low landscape disturbance and high demographic stability (i.e. high natality and philopatry). We propose that such increased philopatry in resource‐rich patches could lead to a functional isolation (‘isolation by resource’) exacerbating the negative effects of landscape modification because of isolation by distance and/or resistance, especially in species with low dispersal capability. Our results also indicate that high levels of genetic diversity may be associated with low (rather than high) patch quality because populations in such patches could be composed predominantly of (unrelated) immigrants.

editorial ISSN 1948-6596 Biogeography of a fragmenting world Part of the value of biogeography as a multidiscipli- nary transversal science is its wide applicability to processes that occur at multiple scales. One such process is the extinction of species resulting from the disappearance of their habitats. Habitat loss and fragmentation are widespread, and, together with habitat degradation and other human im- pacts, they probably constitute the aspect of global change that contributes the most to current extinc- tion rates (see, e.g., Sandom et al. 2014), although climate change and biological invasions also play significant roles in changing the ecological dynam- ics of species (see the book reviews by Hinsley 2015 and Cassey 2015 in this issue). Island biogeography is particularly useful for understanding the complex effects of habitat loss and fragmentation on biodiversity, for it provides a solid theoretical background to study and model extinction trends (Harris 1984). Using this concep- tual framework, Matthews (2015) studied different aspects of biodiversity variation in habitat frag- ments, finding that trends in these habitat islands are complex and change from one system to an- other, with traditional island biogeographic rela- tionships only being applicable to a very limited extent. Importantly, some of this lack of transfera- bility can be attributed to the effects of non-native species or the characteristics of human disturb- ance, rather than to a lack of generality of the prin- ciples of island biogeography. Further, the nature and extent of habitat degradation in the matrix surrounding the habitat islands turn out to be im- portant in Matthews’ (2015) research, adding a new dimension to island biogeographic enquiry. High-quality datasets such as the one provided by Bergamin et al. (2015) for the vegetation of the highly fragmented Brazilian Atlantic forest will fur- ther enhance our knowledge about the effects of habitat transformation on biodiversity loss. Islands can also contribute to the study of habitat change and extinctions in that they can act as natural experiments, where isolation has result- ed in the existence of many (pseudo)replicates of limited size with similar ecological conditions and similar but, at the same time, independent evolu- tionary processes and species pools. The work of Lavery (2015) on northern Melanesian mammals is a nice example of how the distribution, ecology and evolution of several groups and lineages can be studied from a holistic, multidisciplinary per- spective in archipelagos and island complexes. This integrative perspective is also adopted for the study of particular biomes, such as the South Afri- can Fynbos (Ojeda 2015), but is particularly difficult when these biomes occupy large areas or are locat- ed in areas with considerable biotic interchange. Some of the complexity of continental set- tings can be untangled by studying areas of inter- mediate isolation, such as peninsulas, and explicitly addressing temporal patterns. The combination of data on past (through pollen) and current distribu- tion of species with macroecological and multivari- ate analyses allow Gavin (2015) to study the stabil- ity of habitats in the Olympic Peninsula (Washington, USA) throughout the end of the Pleistocene and the Holocene. At a larger temporal scale, the macroevolutionary study of extinction risk allows understanding of which species may be more prone to extinction, although habitat loss continues to play a major role in determining which species may be finally lost (DeNeve et al. 2015). Here, the important development of statisti- cal tools to analyse temporal and spatial data (Dale & Fortin 2015, Hartig 2015) allows understanding of trends and drivers from multiple sources of da- ta. A multidisciplinary approach, using transversal frameworks and addressing topics of broad inter- est to biogeographers, can perhaps best account for the many facets of the impacts of global change. This major strength of biogeography is nicely encapsulated by the papers within this issue of Frontiers of Biogeography. Joaquin Hortal 1 and Richard Field 2 Frontiers of Biogeography editors-in-chief Departament of Biogeography and Global Change, Museo Nacional de Ciencias Naturales (MNCN-CSIC), 28006 Madrid, Spain. jhortal@mncn.csic.es School of Geography, University of Nottingham, NG7 2RD, UK. richard.field@nottingham.ac.uk frontiers of biogeography 7.2, 2015 — © 2015 the authors; journal compilation © 2015 The International Biogeography Society