Low Dispersal Ability Research Articles

How did subterranean amphipods cross the Adriatic Sea? Phylogenetic evidence for dispersal–vicariance interplay mediated by marine regression–transgression cycles

AbstractAimFreshwater subterranean amphipods with low dispersal abilities are known from both sides of the impermeable barrier, the Adriatic Sea. We tested the hypothesis that historical marine regression–transgression cycles shaped the distribution patterns of subterranean amphipods through repeated cycles of dispersal and vicariance against the hypothesis that subterranean amphipods colonized both sides of the Adriatic Sea independently.LocationWestern Balkan Peninsula, Adriatic Sea Islands and Apennine Peninsula, Europe.TaxonGenus Niphargus, a clade of freshwater subterranean amphipods (Crustacea: Amphipoda).MethodsThe taxonomic structure of the studied clade was revised using unilocus species delimitation methods. The timeframe of cladogenetic events was inferred using a multi‐locus time‐calibrated phylogeny and compared to the main regression–transgression events in the Miocene and Pleistocene. The geographical origin of the studied clade, species range expansions and contractions, as well as vicariance events were assessed through modelling of historical biogeography.ResultsSubterranean amphipods of the genus Niphargus, found on both sides of the Adriatic Sea, form a monophylum. The reconstructions of ancestral ranges suggest that the clade emerged in the Balkan Peninsula, dispersed three times independently to the Apennine Peninsula and once back to the Balkans. Adriatic Islands were colonized multiple times, predominantly from the Balkan Peninsula. The dispersal–vicariance events correspond to historical regression–transgression cycles in Miocene and Pleistocene.Main conclusionsMarine regression–transgression cycles apparently shaped the distribution patterns of subterranean amphipods while the alternative hypothesis received no support. The actual distribution of subterranean faunas apparently reflects old biogeographical events.

Trait-based climate vulnerability of native rodents in southwestern Mexico.

AimIncorporate species’ trait information together with climate projections for associated habitat to assess the potential vulnerability of rodent taxa to climate change.LocationOaxaca State, Mexico.MethodsWe used a trait‐based approach together with climate exposure models to evaluate the vulnerability of rodent species to projected climate conditions in the study region. Vulnerability was estimated based on three factors: (a) Level of climatic exposure that species are projected to experience across their current statewide range; (b) inherent species‐specific sensitivity to stochastic events; and (c) species’ capacity to cope with climate change effects. We defined species as inherently sensitive if they had any of the following: restricted geographic distribution in Mexico; narrow altitudinal range; low dispersal ability; or long generation length.ResultsVulnerability varied depending on the climate change scenario applied. Under the MPI general circulation model and current emissions trends, by 2099, all species evaluated were projected to have some level of threat (vulnerable for at least one factor), with 4 out of 55 species vulnerable for all three factors, 29 for two factors, and 22 for one factor. Six out of ten rodent species endemic to Oaxaca were vulnerable for two or more factors. We found that species with narrow and restricted‐range distributions combined with low adaptive capacity were projected to be particularly vulnerable.Main conclusionsBy including species‐specific trait information in climate exposure assessments, researchers can contextualize and enhance their understanding about how climate change is likely to affect individual taxa in an area of interest. As such, studies like this one provide more relevant threat assessment information than exposure analyses alone and serve as a starting point for considering how climatic changes interact with an array of other variables to affect native species across their range.

Flower morphology is correlated with distribution and phylogeny in Bertolonia (Melastomataceae), an herbaceous genus endemic to the Atlantic Forest

Several centers of endemism have been proposed for Melastomataceae, particularly in Amazonia and Atlantic Forest. Despite the high degree of human-caused degradation in the last 500 years, the Atlantic Forest still presents some of the largest levels of diversity and endemism across all angiosperms. With several recently described species in the last decade, the knowledge on Bertolonia’s distribution and morphological characterization has changed, with most new species found in northern Atlantic Forest and with different flower color patterns than the species from southern Atlantic Forest. We first tested the monophyly of the genus sampling over 85% of its species to generate a reliable phylogenetic hypothesis. Afterwards, we used Bertolonia as a model group to study distribution patterns and morphological evolution of lineages in the Atlantic Forest. Bertolonia is particularly interesting to address such questions because it is endemic to this domain, with species distributed either in the southern, central or northern portions of the Atlantic Forest. The second step of our work aimed to respond (1) Do closely related species endemic to Atlantic Forest tend to have similar distributions and share similar morphological traits? and (2) Are floral traits more conserved within clades than vegetative characters? We hypothesize that both (1) and (2) are true due to the low dispersal ability and consequent microendemic distribution of most species in the genus. Our results confirm the veracity of the proposed hypotheses. Three major groups were recovered in our analysis: marmorata, formosa and nymphaeifolia clades. Most species that occur in northern Atlantic Forest were recovered in the marmorata clade. Most species distributed in central Atlantic Forest were recovered in the formosa clade, and the ones from the southern Atlantic Forest in the nymphaeifolia clade. A similar pattern was recovered with reproductive characters reconstructed across the phylogeny. Generally, species with pink petals and cream-colored anthers with an extrorse pore occur in northern Atlantic Forest, and species with white petals and yellow anthers with an introrse or apical pore tend to occur in southern Atlantic Forest. Some vegetative characters also have evolutionary congruence and are restricted to one or few lineages, while other characters, such as the texture of the leaf blade surface, have a strong taxonomic value and are useful to identify species, but are not homologous. Our analysis also indicates that the division between southern and northern Atlantic Forest could also be related to ancient events, not only linked with recent phylogeographic patterns. Moreover, we suggest that the orientation of the anther pore in Bertolonia could be related with diversity of species and stability of its populations. In summary, we corroborate, based on the evolutionary history of Bertolonia, that closely related species endemic to Atlantic Forest tend to have similar distributions and share similar morphological floral traits.

Linking plant conservatism scores to plant functional traits

Many indices to assess ecosystem health involve conservatism scores (C-scores), which are assigned to individual plant species by expert regional botanists and are intended to provide a semi-quantitative metric of a species’ tolerance to environmental perturbation. However, C-scores are based on expert opinion and cannot be generalized because they are not based on explicit physiological or ecological information. Here, we examine the relationship between C-scores and plant functional traits to evaluate whether C-scores could be predicted by the morphology, life history, dispersal, reproduction, disturbance tolerance, or resource use efficiency of plant species. We compiled data on 27 such functional traits for 1042 plant species inhabiting the Northern Great Plains ecoregion of USA and Canada. We found significant relationships between C-score and several functional traits. Fire- and salt-tolerant species had C-scores 3.5 and 2 units lower than intolerant species; shade-tolerant species had C-scores 4 units higher than intolerant species. Species sensitive to environmental perturbation (i.e. with high C-score) generally had traits associated with low dispersal ability and germination success, slow growth rates, and high resource use efficiency. For example, species which propagate only vegetatively had average C-scores 4.5 units higher than species which propagate only by seed; germination success was 10% lower for species with the highest versus lowest C-scores; species with slow growth rates had average C-scores 4 units higher than species with fast growth rates; and leaf nitrogen content was 25% lower for species with the highest versus lowest C-scores. These findings illustrate the connection between C-scores and plant functional traits and suggest that C-scores may be extrapolated to other species with consistent traits. Further, linking functional traits to C-scores can improve predictions of how plants might respond to altered environmental conditions.

Multiple dimensions of climate change on the distribution of Amazon primates

Owing to climate change, species’ geographical distribution may be extended, reduced or displaced in the future. Across species’ ranges, novel climate conditions may also expose species to thermal conditions for which they are not adapted. Migration toward more suitable climates will, however, only be possible if species are able to keep pace with climate change. Here, we analyze different metrics to predict the impacts of climate change on the distribution of Amazon primates. We found that this iconic group will be exposed to novel climate conditions in a large portion of their territories and most species might not be able to track their preferred environmental conditions, even when their range is forecasted to expand. Remaining future populations are expected to become fragmented and to occupy sub-optimal conditions at the periphery of their projected bioclimatic envelopes. Our results suggest that climate change may have unprecedented impacts on Amazon biodiversity, especially for species with low dispersal ability, such as primates. In addition to deforestation, hunting, and disease spread, climate change is likely to add up to conservation-defying feedbacks for Amazon primate populations’ fitness and resilience dynamics.

Metacommunity Structure of Stream Insects across Three Hierarchical Spatial scales.

A major challenge in community ecology is to understand the underlying factors driving metacommunity (i.e., a set of local communities connected through species dispersal) dynamics. However, little is known about the effects of varying spatial scale on the relative importance of environmental and spatial (i.e., dispersal related) factors in shaping metacommunities and on the relevance of different dispersal pathways. Using a hierarchy of insect metacommunities at three spatial scales (a small, within‐stream scale, intermediate, among‐stream scale, and large, among‐sub‐basin scale), we assessed whether the relative importance of environmental and spatial factors shaping metacommunity structure varies predictably across spatial scales, and tested how the importance of different dispersal routes vary across spatial scales. We also studied if different dispersal ability groups differ in the balance between environmental and spatial control. Variation partitioning showed that environmental factors relative to spatial factors were more important for community composition at the within‐stream scale. In contrast, spatial factors (i.e., eigenvectors from Moran's eigenvector maps) relative to environmental factors were more important at the among‐sub‐basin scale. These results indicate that environmental filtering is likely to be more important at the smallest scale with highest connectivity, while dispersal limitation seems to be more important at the largest scale with lowest connectivity. Community variation at the among‐stream and among‐sub‐basin scales were strongly explained by geographical and topographical distances, indicating that overland pathways might be the main dispersal route at the larger scales among more isolated sites. The relative effect of environmental and spatial factors on insect communities varied between low and high dispersal ability groups; this variation was inconsistent among three hierarchical scales. In sum, our study indicates that spatial scale, connectivity, and dispersal ability jointly shape stream metacommunities.

Species–area relationship and small‐island effect of bryophytes on the Zhoushan Archipelago, China

AbstractAimThe species–area relationship (SAR) and the small‐island effect (SIE) are of important ecological significance. However, few studies have focused on these topics in regard to bryophytes. We aimed to (1) determine whether SIEs and a SAR with two thresholds and three different processes of species addition exist for bryophytes across continental islands and (2) test whether the SIE threshold tends to be high for stenoecious species with a high sensitivity to habitats and for those with relatively high resource requirements and low dispersal abilities.LocationThe Zhoushan Archipelago, China.TaxonBryophytes.MethodsWe obtained species number data for five bryophyte categories (total bryophytes, total mosses, acrocarpous mosses, pleurocarpous mosses and liverworts) from 66 continental islands of the archipelago and analysed the dataset using 24 SAR models. According to Akaike's information criterion, we identified models suitable for revealing SARs and detecting SIEs among the five bryophyte categories.ResultsThe power model was best for fitting SARs of all bryophyte categories except for pleurocarpous mosses. For detecting SIEs, the three‐segmented model provided the best support for the five categories. There were obvious SIEs for the five bryophyte groups, with area thresholds of 0.11–1.42 km2. The SIE threshold was much higher in liverworts than in mosses and in pleurocarpous mosses than in acrocarpous mosses. The second thresholds for the five categories were similar, ranging from 53.62 to 73.19 km2.Main conclusionsA unique SAR pattern with two area thresholds and three different dominant processes of species addition with island area was found for bryophytes across the continental islands. The second thresholds were not due to in situ speciation but were likely due to the high immigration of bryophytes from the mainland attributed to local residents. The SIE thresholds detected for the different categories of bryophytes indicated that the values tended to be low for species groups with low resource requirements and high dispersal abilities and high for those with a high sensitivity to habitat conditions, the latter indicating that areas for conservation purposes for species sensitive to habitats should be comparatively large.

The geographic distribution of Protura (Arthropoda: Hexapoda): a review

Protura is a poorly known class of Hexapoda represented by more than 800 species belonging to 77 genera worldwide. They are tiny soil organisms with low dispersal ability, mainly attributable to water and human-mediated transfer. The analysis of biogeography of Protura is hindered by the lack of knowledge on their natural history, systematics and distribution. In order to provide a starting point for future more detailed investigations, we reviewed the available literature on their geographic distribution, making a distinction between continental and insular areas. A general overview based on Wallace’s biogeographic regionalization is outlined, highlighting a maximum of known richness and endemism at the genus level in the Palearctic region, and particularly within its eastern part. Some detailed examples of disjunct distribution and their interpretation based on vicariance or dispersal events are given.

Survey on Drosophila suzukii Natural Short-Term Dispersal Capacities Using the Mark−Release−Recapture Technique

Spotted wing drosophila, Drosophila suzukii Matsumura (Diptera: Drosophilidae), has become a key pest for soft fruits and cherries in Europe in less than a decade since the first outbreak in 2007. Although this pest’s passive dispersal ability has been observed over more than 1400 km in 1 year, active spread has not yet been extensively studied. A mark−release−recapture (MRR) method based on protein-marked flies was employed to determine the flight capacity of D. suzukii. Sterile marked flies were released and recaptured in a trap grid at increasing distances from 10 to 250 m from the releasing point to study flight distance during periods ranging from 3 h to 1 week. MRR experiments were replicated in the presence and absence of host fruits to study how they could affect dispersal behavior. The dispersal capacity of the Mediterranean fruit fly, Ceratitis capitata Wiedemann (Diptera: Tephritidae) was also studied under the same conditions. The results showed a low dispersal ability for D. suzukii, with a daily flight distance below 100 m with no predominant wind. The implications on natural dispersion and control methods based on attractants are discussed.

Combining functional traits and phylogeny to disentangling Amazonian butterfly assemblages on anthropogenic gradients

AbstractEnvironmental gradients consist of sequential changes in the physical and structural characteristics of a region. These allow us to follow species responses and tolerances under different habitat conditions. Among them, forest fragmentation and succession comprise the most common examples of forest gradients, where organismal responses require distinct morphological, physiological, and behavioral adaptations. However, environmental changes can impose ecological and evolutionary constraints that act on species traits, as well as on local species assemblies through their phylogenetic history. In this study, we evaluated the differences in species distribution and composition on fruit‐feeding butterfly assemblages along forest fragmentation and succession gradients. We combine functional and phylogenetic methods for determining butterfly assemblages, and inferred species resistance and resilience according to habitat changes in tropical forests. We used a database of 471 fruit‐feeding butterflies of 60 species sampled from different environments in the central Amazon rainforest. A total of 13 functional traits were measured, and a phylogenetic tree was obtained for the sampled species. The trait–environment relationship was analyzed along both forest fragmentation and succession gradients, controlling for phylogenetic signal on species distribution and functional composition when necessary. Several traits presented phylogenetic signal, and phylogeny was also driving butterfly species distribution along the successional gradient. After controlling for phylogeny, individual characteristics related to flight speed (thoracic weight) and anti‐predatory strategies (camouflage) increased in early‐successional forests, with large butterflies (body length) prevailing in primary forests. No clear functional and phylogenetic pattern was identified for the fragmentation gradient. Our results are consistent with the idea that butterflies may be employing distinct functional strategies to attenuate habitat change effects. Larger butterflies, with lower dispersal ability, are preferentially susceptible to local extinctions in the early‐successional environments, mainly when forested habitat and its resources become spatially restricted. In addition, several anti‐predatory strategies related to conspicuous colors may be losing their functionality in open areas, where not being distinctive against the background becomes the primary defense against predation.

High altitude endemic carabid beetles as biogeographic indicators: a case study in equatorial Andes

The tropical Andean páramo ecosystem emerged after the final uplift of the Cordilleras, leading to the rapid radiation of species-rich clades and to the diversification of narrow-range endemic taxa in isolated high-altitude island-like environments. This study focuses on the wingless carabid species that inhabit the so-called superpáramo, i.e. the upper belt of this ecosystem, above 4200/4300 m a.s.l. The low dispersal ability of these cold-adapted ground beetles gives the opportunity of an exceptionally fine-grained analysis of endemism patterns. Two hypotheses are tested: (i) that most of these endemic carabids have evolved by niche shift, from local ancestors in the montane forest, rather than by long range dispersal from cool regions north or south, and (ii) that the high level of microendemism observed in several genera is the result of recent speciation events, related to the volcanic and tectonic history of the Andes. More than 14,000 carabid beetles were collected above 4200 m on 12 superpáramo “sky islands” in central and northern Ecuador, using standardized sampling methods. COI sequencing was performed to strengthen species delimitations, and a further molecular study was conducted for phylogeographic analyses in two highly diverse genera: Oxytrechus (Trechini) and Dyscolus (Platynini). Of a total of 89 species, 65 species are microendemic, i.e. restricted to only one isolated superpáramo. The first results of this ongoing project are presented with a highlight on the extinction risk caused by the current climate change.

The scale of saproxylic beetles response to landscape structure depends on their habitat stability

Forest management and disturbances cause habitat fragmentation for saproxylic species living on old-growth attributes. The degree of habitat spatiotemporal continuity required by these species is a key question for designing biodiversity-friendly forestry, and it strongly depends on species’ dispersal. The “stability–dispersal” model predicts that species using stable habitats should have lower dispersal abilities than species associated with ephemeral habitat and thus respond to habitat availability at smaller scales. We aimed at testing the stability–dispersal model by comparing the spatial scales at which saproxylic beetle guilds using substrates with contrasted stability (from stable to ephemeral: cavicolous, fungicolous, saproxylophagous and xylophagous guilds) are affected by landscape structure (i.e. habitat amount and aggregation). We sampled saproxylic beetles using a spatially nested design (plots within landscape windows). We quantified habitat availability (tree cavities, polypores and deadwood) in 1-ha plots, 26-ha buffers around plots and 506-ha windows, and analyzed their effect on the abundance and diversity of associated guilds. The habitat amount within plots and buffers positively affected the abundance of the cavicolous and the fungicolous guilds whereas saproxylophagous and xylophagous did not respond at these scales. The habitat aggregation within windows only positively affected the saproxylophagous species richness within plots and also on the similarity in species composition among plots. Beetle guilds specialized on more stable habitat were affected by landscape structure at smaller spatial scales, which corroborated the stability–dispersal model. In managed forests, the spatial grain of conservation efforts should therefore be adapted to the target habitat lifetime.

Global warNing: what we know and what we should know about carabid beetles in high altitude habitats

Models that relate species distributions and climate to predict the future geographical range of species in response to forecast climate change have shown that species living at high altitudes are expected to be particularly affected. Presently, the global trend towards a rapid climate warming represents a major concern for high-altitude carabid beetles, specifically for the populations living in glacialised mountain areas. Most of the high altitude carabid species are endemic and cold-adapted, have low dispersal abilities and present small and/or isolated populations. These threats are triggering an increase of their extinction risk. Some researchers have demonstrated both local-scale extinctions and upward shift to higher altitudes. A key point is whether the losses determined by climate change could be mitigated by species’ survival in micro-refugium areas. Traditionally, the current species distribution in climate-limited ecosystems, like those at high altitude, have been described underlining the role of cold-stage refugia during the Last Glacial Maximum (c. 22000 years BP). On the other hand, no studies addressed the question if the present-day distribution of cold-adapted mountain species is driven by climate conditions occurring during the past and/or current warm periods. More recently, the potential role of some ice-related mountain landforms as warm-stage refugia was documented. It suggests that these landforms could be able to promote the long-term survival of cold-adapted species when the surrounding habitats become climatically unfavorable, thus more effort should be done to investigate the ecology these kind of harsh habitats.

Nebria germari Heer, 1837 – insight about the distribution and ecology of a climate-sensitive species of the Eastern Alps

Nebria germari (Coleoptera: Carabidae) is a cold-adapted species currently restricted to high altitude habitats of the Eastern Alps and exhibits fragmented distribution patterns suggesting refugial occurrence. It is a brachypterous species (thus with low dispersal ability) and it has nocturnal forage behaviour (mainly predating springtails and midges). Since N. germari is an endemic and a climate-sensitive species, we performed a study aimed at describing the past distribution on the Dolomites (Italy), the ecology and the current population dynamic on debris-covered glaciers of this area where it is still abundant. The past distribution was investigated by reviewing literature and analysing the labels of the specimens preserved in some Museum collections. We found that, until the second half of the last century, the lower altitudinal limit of this species was around 2000 m asl. Specifically, it was abundant in alpine grasslands on carbonate substrata (Carex firma-dominated). Field data collected in the last ten years demonstrated the current extinction in this grassland type of the Southern Alps, with a consequent contraction of the distribution. Currently, N. germari is still abundant in high altitude, north-faced, scree slopes with macroporal soil structure, in deep underground and on debris-covered glaciers due to its preference for cold temperatures (i.e. terrains with average annual temperature of ca. 0°C). Preliminary results obtained analysing, through the snow-free period, the larval, sub-adult and adult abundance patterns on debris-covered glaciers suggest that, in this kind of harsh habitat, N. germari is a spring rather than an autumn breeder as was documented in the last century for the populations found in high alpine prairies. In addition, the population size seems to decrease from the snowmelt to the beginning of the snow period and to increase with the percentage of coarse fraction of the terrain. Conversely, no significant relation was found between the population size and the abundance of preys (Collembola) and competitors (Araneae).

On three new species of Elpidium Müller, 1880 and the re-description of Elpidium laesslei (Tressler, 1956) from Jamaica (Ostracoda: Podocopida: Limnocytheridae).

Elpidium ostracods are known by their very particular niche (water accumulated in tank-bromeliads), their relatively low dispersal ability and their dependency on amphibians for dispersal and colonization of new bromeliads. All these characteristics make the genus an interesting group for evolutionary, ecological and even taxonomic studies. However, the diversity of the group remains poorly studied. Here, we describe three new species of Elpidium, Elpidium littlei n. sp., Elpidium heberti n. sp. and Elpidium wolfi n. sp., and re-describe Elpidium laesslei, all from Jamaica. These species are characterized by a copulatory process with separated ejaculatory duct and distal glans, a feature so far unique within the genus. Each species can, in turn, be diagnosed by soft part and carapace morphology, most notably comparing hemipenis, valve ornamentation and degree of sexual dimorphism. The observed morphological diversity of Elpidium is discussed in relation to previous genetic estimates that suggested an even higher diversity in Jamaica. We point to intraspecific variation and lack of complete morphological descriptions as possible explanations. We also reaffirm the need of multidisciplinary studies in order to do more objective and secure taxonomic classifications in future studies.

Phylogeographic patterns and conservation implications of the endangered Chinese giant salamander.

Understanding genetic diversity patterns of endangered species is an important premise for biodiversity conservation. The critically endangered salamander Andrias davidianus, endemic to central and southern mainland in China, has suffered from sharp range and population size declines over the past three decades. However, the levels and patterns of genetic diversity of A. davidianus populations in wild remain poorly understood. Herein, we explore the levels and phylogeographic patterns of genetic diversity of wild‐caught A. davidianus using larvae and adult collection with the aid of sequence variation in (a) the mitochondrial DNA (mtDNA) fragments (n = 320 individuals; 33 localities), (b) 19 whole mtDNA genomes, and (c) nuclear recombinase activating gene 2 (RAG2; n = 88 individuals; 19 localities). Phylogenetic analyses based on mtDNA datasets uncovered seven divergent mitochondrial clades (A–G), which likely originated in association with the uplifting of mountains during the Late Miocene, specific habitat requirements, barriers including mountains and drainages and lower dispersal ability. The distributions of clades were geographic partitioned and confined in neighboring regions. Furthermore, we discovered some mountains, rivers, and provinces harbored more than one clades. RAG2 analyses revealed no obvious geographic patterns among the five alleles detected. Our study depicts a relatively intact distribution map of A. davidianus clades in natural species range and provides important knowledge that can be used to improve monitoring programs and develop a conservation strategy for this critically endangered organism.

Climate change-induced range shift of the endemic epiphytic lichenLobaria pindarensisin the Hindu Kush Himalayan region

AbstractThe Hindu Kush Himalayan (HKH) region harbours some of the richest and most diverse ecosystems on the planet that are now facing substantial threats through changes in climate, land use and human population growth, with serious consequences for the biodiversity in this mountainous region. In this paper we evaluated the effects of climate change on the distribution of the tripartite epiphytic macrolichenLobaria pindarensis, considered to be endemic to the Himalayas. To predict the current and future distribution of this species we applied the Random Forest modelling algorithm and climatic variables with a post-processing of projected distributions using a map of habitat types in the study region. We calibrated models based on 1397 species presences within an altitudinal range of 2036–4000 m and extrapolated them according to two IPCC scenarios of climate change (RCP 2·6 and RCP 8·5). Based on the results of ensemble modelling, two new localities whereL. pindarensismight potentially occur were predicted. Our simulations predicted a range expansion of this epiphytic lichen to the north-east and to higher altitudes in response to climate change, although the species’ low dispersal abilities and the local availability of trees as a substratum will considerably limit latitudinal and altitudinal shifts. By contrast, assuming the species can migrate to previously unoccupied areas, and depending on different future climate scenarios, our models forecasted a habitat loss of 30–70% forL. pindarensis.The main reason for the simulated habitat loss is the expected increase in mean annual temperature (by 1·5–3·7 °C) and total annual precipitation (by 56–125 mm). Our results contribute further evidence for the high sensitivity of tripartite macrolichens, especially those from mountain areas, to climate change and particularly emphasize the vulnerability ofL. pindarensis. Thus, we stress the need to develop and formulate conservation measures and strategies for the protection of this endemic species in the Hindu Kush Himalayan region.

Resources and soil influencing habitat selection by a subterranean rodent in a high cold desert

Selection occurs when animals choose from among alternative habitat resources they find available in the environment. As selection is a hierarchical process, it can be studied at multiple spatial scales. Subterranean rodents are a good model to study habitat selection because of their low dispersal ability and easily identifiable perturbed areas. Using a comparative data from multiple distinct locations, we analyzed if Ctenomys mendocinus selects different habitat units at a macroscale and identify which variables most influence its activity at a microscale. We conducted this study in an extreme environment in terms of resource abundance and climatic conditions, generating interesting new insights into patterns of habitat selection by this species. We found that minimum soil depth and the abundance of Fabiana punensis shrub were the most important variables determining C. mendocinus activity at the microscale. Also, the changes in these variables may probably influence the selection of habitat units found at the macroscale.

Population genetics and biophysical modeling inform metapopulation connectivity of the Caribbean king crab Maguimithrax spinosissimus

MEPS Marine Ecology Progress Series Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsTheme Sections MEPS 610:83-97 (2019) - DOI: https://doi.org/10.3354/meps12842 Population genetics and biophysical modeling inform metapopulation connectivity of the Caribbean king crab Maguimithrax spinosissimus J. Antonio Baeza1,2,3,*, Daniel Holstein4, Rodolfo Umaña-Castro5, Luis M. Mejía-Ortíz6 1Department of Biological Sciences, Clemson University, Clemson, SC 29634, USA 2Smithsonian Marine Station at Fort Pierce, Fort Pierce, FL 34949, USA 3Departamento de Biología Marina, Facultad de Ciencias del Mar, Universidad Católica del Norte, Coquimbo, Chile 4Department of Oceanography and Coastal Sciences, College of the Coast and Environment, Louisiana State University, Baton Rouge, LA 70803, USA 5Laboratorio de Análisis Genómico (LAGEN), Universidad Nacional, Heredia, Costa Rica 6Laboratorio de Bioespeleología y Carcinología, División de Desarrollo Sustentable, Universidad de Quintana Roo, Quintana Roo, Mexico *Corresponding author: jbaezam@clemson.edu ABSTRACT: Marine organisms with a short pelagic larval duration (PLD) are assumed to display significant population structure given low long-distance dispersal ability. For the wider Caribbean, theoretical and empirical considerations suggest that species with short PLDs inhabiting each of the following areas should be genetically distinct: Costa Rica (CR), Mexico (MX), and Florida Keys (FL-K), USA. This study tested the hypothesis of significant genetic differentiation in Maguimithrax spinosissimus populations across the wider Caribbean using a combination of biophysical modeling and population genetics. Biophysical modeling predicted dissimilar connectivity patterns among CR, MX, and FL-K depending upon assumed PLD. Eight days of dispersal only provided rare connections from MX to FL-K, and low likelihood multi-generational connections between CR and FL-K. In turn, 12 d of dispersal was sufficient to connect MX to FL-K through direct and indirect routes in biophysical models, but CR and FL-K remained connected only through multiple generational steps. After 16 d of dispersal, direct connections between CR and FL-K may occur, and by 20 d of dispersal, connections are likely between all sampled patches. Population genetic analyses based on partial sequences of the mtDNA 12S, 16S, and COI genes denoted the existence of a single, relatively high-frequency haplotype shared among all 3 populations, which suggests a longer PLD than predicted by laboratory study. In turn, an analysis of molecular variance and pairwise FST values demonstrated significant genetic differentiation among the studied populations. Altogether, the above information suggests low to moderate connectivity among populations in M. spinosissimus. Subpopulation split predictions suggest multi-generational or stepping-stone connectivity between CR and both MX and FL-K, and provides a framework for understanding the structure of M. spinosissimus metapopulations throughout the region. Overall, this study agrees with the notion of significant population structure in marine species with lower dispersal ability. KEY WORDS: Crab · Demographic history · Coalescence · Phylogeny Full text in pdf format PreviousNextCite this article as: Baeza JA, Holstein D, Umaña-Castro R, Mejía-Ortíz LM (2019) Population genetics and biophysical modeling inform metapopulation connectivity of the Caribbean king crab Maguimithrax spinosissimus. Mar Ecol Prog Ser 610:83-97. https://doi.org/10.3354/meps12842 Export citation RSS - Facebook - Tweet - linkedIn Cited by Published in MEPS Vol. 610. Online publication date: February 01, 2019 Print ISSN: 0171-8630; Online ISSN: 1616-1599 Copyright © 2019 Inter-Research.

Patch‐scale biodiversity retention in fragmented landscapes: Reconciling the habitat amount hypothesis with the island biogeography theory

AbstractAimTo test whether the species richness of understorey insectivorous birds on forest islands induced by a major hydroelectric dam is best explained by either the island biogeography theory (IBT) or the habitat amount hypothesis (HAH). Given the low dispersal ability of the focal species group and the hostile water matrix, we predict that the species richness will be predominantly driven by an island effect as posited by the IBT, rather than a sample area effect as posited by the HAH.LocationForest islands within the Balbina Hydroelectric Reservoir, central Brazilian Amazonia.TaxonBirds.MethodsWe mist‐netted birds at 33 forest islands (0.63–1,699 ha), totalling 874 individuals of 59 species. The size of the local landscape used to calculate the habitat amount was determined by a multi‐scale analysis in which buffers around mist‐net lines ranged from 50 to 2,000 m. We applied four tests to examine whether the species richness on forest islands is predominantly driven by either an island effect (island size) or a sample area effect (habitat amount).ResultsFrom the four tests applied, one was consistent with an island effect, two were regarded as inappropriate to test the HAH, and one could not be adequately addressed due to island size being highly correlated with habitat amount in the local landscape (200‐m buffer).Main conclusionsSome of the proposed ways of testing the HAH may lead to misleading conclusions. The relative importance of island size in determining the species richness of understorey insectivorous birds on forest islands is higher than that of surrounding habitat amount, thereby providing stronger support for IBT. We propose a conceptual framework, based on the degree of matrix permeability and species dispersal ability, to determine to what extent a patch‐ or landscape‐centric worldview in landscape ecology provides the most appropriate framework to assess the effects of habitat fragmentation on biodiversity.