Concealed truth: Modeling reveals unique Quaternary distribution dynamics and refugia of four related endemic keystone Abies taxa on the Tibetan Plateau

Understanding the factors driving the Quaternary distribution of Abies in the Tibetan Plateau (TP) is crucial for biodiversity conservation and for predicting future anthropogenic impacts on ecosystems. Here, we collected Quaternary paleo‐, palynological, and phylogeographical records from across the TP and applied ecological niche models (ENMs) to obtain a profound understanding of the different adaptation strategies and distributional changes in Abies trees in this unique area. We identified environmental variables affecting the different historical biogeographies of four related endemic Abies taxa and rebuilt their distribution patterns over different time periods, starting from the late Pleistocene. In addition, modeling and phylogeographic results were used to predict suitable refugia for Abies forrestii, A. forrestii var. georgei, A. fargesii var. faxoniana, and A. recurvata. We supplemented the ENMs by investigating pollen records and diversity patterns of cpDNA for them. The overall reconstructed distributions of these Abies taxa were dramatically different when the late Pleistocene was compared with the present. All Abies taxa gradually receded from the south toward the north in the last glacial maximum (LGM). The outcomes showed two well‐differentiated distributions: A. fargesii var. faxoniana and A. recurvata occurred throughout the Longmen refuge, a temporary refuge for the LGM, while the other two Abies taxa were distributed throughout the Heqing refuge. Both the seasonality of precipitation and the mean temperature of the driest quarter played decisive roles in driving the distribution of A. fargesii var. faxoniana and A. recurvata, respectively; the annual temperature range was also a key variable that explained the distribution patterns of the other two Abies taxa. Different adaptation strategies of trees may thus explain the differing patterns of distribution over time at the TP revealed here for endemic Abies taxa.     

Linking ecology,morphology, and metabolism: Niche differentiation in sympatric populations of closely related species of the genus Littorina (Neritrema)

Divergence of ecological niches in phylogenetically closely related species indicates the importance of ecology in speciation, especially for sympatric species are considered. Such ecological diversification provides an advantage of alleviating interspecies competition and promotes more efficient exploitation of environmental resources, thus being a basis for ecological speciation. We analyzed a group of closely related species from the subgenus Neritrema (genus Littorina, Caenogastropoda) from the gravel‐bouldery shores. In two distant sites at the Barents and Norwegian Sea, we examined the patterns of snail distribution during low tide (quantitative sampling stratified by intertidal level, presence of macrophytes, macrophyte species, and position on them), shell shape and its variability (geometric morphometrics), and metabolic characteristics (metabolomic profiling). The studied species diversified microbiotopes, which imply an important role of ecological specification in the recent evolution of this group. The only exception to this trend was the species pair L. arcana / L. saxatilis, which is specifically discussed. The ecological divergence was accompanied by differences in shell shape and metabolomic characteristics. Significant differences were found between L. obtusata versus L. fabalis and L. saxatilis / L. arcana versus L. compressa both in shell morphology and in metabolomes. L. saxatilis demonstrated a clear variability depending on intertidal level which corresponds to a shift in conditions within the occupied microhabitat. Interestingly, the differences between L. arcana (inhabiting the upper intertidal level) and L. compressa (inhabiting the lower one) were analogous to those between the upper and lower fractions of L. saxatilis. No significant level‐dependent changes were found between the upper and lower fractions of L. obtusata, most probably due to habitat amelioration by fucoid macroalgae. All these results are discussed in the contexts of the role of ecology in speciation, ecological niche dynamics and conservatism, and evolutionary history of the Neritrema species.     

Invasion of Old World Phragmites australis in the New World: precipitation and temperature patterns combined with human influences redesign the invasive niche

After its introduction into North America, Euro‐Asian Phragmites australis became an aggressive invasive wetland grass along the Atlantic coast of North America. Its distribution range has since expanded to the middle, south and southwest of North America, where invasive P. australis has replaced millions of hectares of native plants in inland and tidal wetlands. Another P. australis invasion from the Mediterranean region is simultaneously occurring in the Gulf region of the United States and some countries in South America. Here, we analysed the occurrence records of the two Old World invasive lineages of P. australis (Haplotype M and Med) in both their native and introduced ranges using environmental niche models (ENMs) to assess (i) whether a niche shift accompanied the invasions in the New World; (ii) the role of biologically relevant climatic variables and human influence in the process of invasion; and (iii) the current potential distribution of these two lineages. We detected local niche shifts along the East Coast of North America and the Gulf Coast of the United States for Haplotype M and around the Mississippi Delta and Florida of the United States for Med. The new niche of the introduced Haplotype M accounts for temperature fluctuations and increased precipitation. The introduced Med lineage has enlarged its original subtropical niche to the tropics‐subtropics, invading regions with a high annual mean temperature (> ca. 10 °C) and high precipitation in the driest period. Human influence is an important factor for both niches. We suggest that an increase in precipitation in the 20th century, global warming and human‐made habitats have shaped the invasive niches of the two lineages in the New World. However, as the invasions are ongoing and human and natural disturbances occur concomitantly, the future distribution ranges of the two lineages may diverge from the potential distribution ranges detected in this study.     

Nature protection areas of Europe are insufficient to preserve the threatened beetle Rosalia alpina (Coleoptera: Cerambycidae): evidence from species distribution models and conservation gap analysis

1. Natura 2000 network (N2000) and national protected areas (NPAs) are recognised as the most important core ‘units’ for biological conservation in Europe. 2. Species distribution models (SDMs) were developed to detect the potential distribution of the rare and threatened cerambycid beetle Rosalia alpina L. in Europe, and the amount of suitable habitat within the N2000 network [special areas of conservation (SACs) and special protection areas (SPAs)], NPAs (e.g. national parks, regional parks, state reserves, natural monuments and protected landscapes) and the overall European protected area network (EPAN) (N2000 + NPAs) was quantified. 3. According to this analysis, the suitable habitat for R. alpina in Europe amounts to c. 754 171 km² and stretches across substantially uninterrupted areas from Portugal to Romania (west to east) and from Greece to Germany (south to north). The overlay between the existing system of conservation areas in Europe (N2000 and NPAs) and the binary map for R. alpina showed that only c. 42% of potential habitat is protected. SACs and SPAs protect c. 25% and 21% of potential habitat, respectively. However, because the two site types often spatially overlap, when taken together the entire N2000 network protects c. 31% of potential habitat. Instead, NPAs offer a degree of protection of c. 29%. Overall, almost 60% of the area potentially suitable for the species is unprotected by the EPAN, an aspect that should be considered carefully when planning the conservation of this beetle at a large scale. 4. These results may also help to focus field surveys in selected areas where greater chances of success are encountered to save resources and increase survey effectiveness.     

Climate‐driven geographic distribution of the desert locust during recession periods: Subspecies’ niche differentiation and relative risks under scenarios of climate change

The desert locust is an agricultural pest that is able to switch from a harmless solitarious stage, during recession periods, to swarms of gregarious individuals that disperse long distances and affect areas from western Africa to India during outbreak periods. Large outbreaks have been recorded through centuries, and the Food and Agriculture Organization keeps a long‐term, large‐scale monitoring survey database in the area. However, there is also a much less known subspecies that occupies a limited area in Southern Africa. We used large‐scale climatic and occurrence data of the solitarious phase of each subspecies during recession periods to understand whether both subspecies climatic niches differ from each other, what is the current potential geographical distribution of each subspecies, and how climate change is likely to shift their potential distribution with respect to current conditions. We evaluated whether subspecies are significantly specialized along available climate gradients by using null models of background climatic differences within and between southern and northern ranges and applying niche similarity and niche equivalency tests. The results point to climatic niche conservatism between the two clades. We complemented this analysis with species distribution modeling to characterize current solitarious distributions and forecast potential recession range shifts under two extreme climate change scenarios at the 2050 and 2090 time horizon. Projections suggest that, at a global scale, the northern clade could contract its solitarious recession range, while the southern clade is likely to expand its recession range. However, local expansions were also predicted in the northern clade, in particular in southern and northern margins of the current geographical distribution. In conclusion, monitoring and management practices should remain in place in northern Africa, while in Southern Africa the potential for the subspecies to pose a threat in the future should be investigated more closely.     

Lazarus ecology: Recovering the distribution and migratory patterns of the extinct Carolina parakeet

The study of the ecology and natural history of species has traditionally ceased when a species goes extinct, despite the benefit to current and future generations of potential findings. We used the extinct Carolina parakeet as a case study to develop a framework investigating the distributional limits, subspecific variation, and migratory habits of this species as a means to recover important information about recently extinct species. We united historical accounts with museum collections to develop an exhaustive, comprehensive database of every known occurrence of this once iconic species. With these data, we combined species distribution models and ordinal niche comparisons to confront multiple conjectured hypotheses about the parakeet's ecology with empirical data on where and when this species occurred. Our results demonstrate that the Carolina parakeet's range was likely much smaller than previously believed, that the eastern and western subspecies occupied different climatic niches with broad geographical separation, and that the western subspecies was likely a seasonal migrant while the eastern subspecies was not. This study highlights the novelty and importance of collecting occurrence data from published observations on extinct species, providing a starting point for future investigations of the factors that drove the Carolina parakeet to extinction. Moreover, the recovery of lost autecological knowledge could benefit the conservation of other parrot species currently in decline and would be crucial to the success of potential de‐extinction efforts for the Carolina parakeet.     

Geographical ecology and conservation of Eugenia L. (Myrtaceae) in the Brazilian Cerrado: Past,present and future

Human actions have caused the fragmentation of natural vegetation, habitat loss and climate change. The Cerrado, considered one of the global hotspots of diversity, has suffered great habitat loss due to these factors, which has been aggravated by the agricultural expansion that took place during the last 60 years. In this context, we chose species of the genus Eugenia L. (Myrtaceae) occurring in the Brazilian Cerrado to describe richness patterns and range loss, and determine conservation priorities for the Cerrado. Ecological niche models (ENMs) were applied to calculate the geographical range of each species in the past (Last Glacial Maximum – LGM, 21 000 years ago), present (PIP, representing current climatic conditions – 1760 years ago) and future (near future – NF, 2080–2100). These results were combined to calculate the richness of the group and also to estimate the range loss of these species in the future. Moreover, we evaluated the irreplaceability of areas for species conservation, aiming to maximize the biotic stability of Eugenia species. Our results showed that the highest species richness in the past was found in the southwestern region of the Cerrado and, currently, the richest regions are found in the central and southeastern areas. However, in the future, we predict a shift of the greatest values of richness towards the southeastern region, an area currently occupied by the Atlantic forest. Although areas with high conservation priorities were found scattered across the biome, this shift is worrisome due to the high fragmentation rate and intensive human occupation thoughout the Atlantic region. Thus, conservation efforts should focus on areas found within these limits.     

Contrasting patterns of genetic structure and phylogeography in the marine agarophytes Gelidiophycus divaricatus and G. freshwateri (Gelidiales,Rhodophyta) from East Asia

The evolutionary and population demographic history of marine red algae in East Asia is poorly understood. Here, we reconstructed the phylogeographies of two upper intertidal species endemic to East Asia, Gelidiophycus divaricatus and G. freshwateri. Phylogenetic and phylogeographic inferences of 393 mitochondrial cox1, 128 plastid rbcL, and 342 nuclear ITS2 sequences were complemented with ecological niche models. Gelidiophycus divaricatus, a southern species adapted to warm water, is characterized by a high genetic diversity and a strong geographical population structure, characteristic of stable population sizes and sudden reduction to recent expansion. In contrast, G. freshwateri, a northern species adapted to cold temperate conditions, is genetically relatively homogeneous with a shallow population structure resulting from steady population growth and recent equilibrium. The overlap zone of the two species roughly matches summer and winter isotherms, indicating that surface seawater temperature is a key feature influencing species range. Unidirectional genetic introgression was detected at two sites on Jeju Island where G. divaricatus was rare while G. freshwateri was common, suggesting the occurrence of asymmetric natural hybrids, a rarely reported event for rhodophytes. Our results illustrate that Quaternary climate oscillations have left strong imprints on the current day genetic structure and highlight the importance of seawater temperature and sea level change in driving speciation in upper intertidal seaweed species.     

Further observations of blunt-hooked pentastomids belonging to the genus Raillietiella Sambon, 1910 infecting Hemidactylus brookii (Sauria: Gekkonidae) in Africa and the Caribbean: comparison with closely related Raillietiella spp. from an African skink (Mabuya perrotetii)

Hemidactylus brookii, a gecko possessing great dispersal ability, has apparently spread from West Africa to the Caribbean and South America by natural rafting. The lungs of populations from West Africa and the Greater Antilles (hispaniola and Puerto Rico) are heavily infected by raillietiellied pentastomids. Nigerian populations harbour two distinct species, frequently as concurrent infections, the males of which can be separated principally by marked differences in the morphology of the copulatory spicule. However one of these species cannot be reliably distinguished from Raillietiella teagueselfi, a common parasite of another highly successful coloniser, the Mediterranean gecko H. turcicus in Texas. The other more closely resembles R. frenatus, first described from the lungs of yet another itinerant gecko (H. frenatus) from south east Asia. Raillietiella spp. from both the Hispaniolan and Puerto Rican H. brookii haitianus populations, possess bluntly-rounded spicules of the R. frenatus type, although comparative posterior hook dimensions indicate that they are not closely related to it, or indeed to each other. They clearly comprise recognisably different geographical populations, but it remains unclear as to whether these are endemic or introduced. Both of the Caribbean species are left unnamed because we do not know what proportion of the observed intra- and interspecific variation is genetically based. Analysis of another raillietiellid population from an African skink (Mabuya perrotetii) is also included because it harbours two more species which are not easily distinguished from R. frenatus and R. teagueselfi. More refined diagnostic techniques, ultimately supplemented by life-cycle studies, are required to resolve these taxonomic problems.     

Cloning and molecular characterization of a unique hemolysin gene of Vibrio pommerensis sp. nov.: development of a DNA probe for the detection of the hemolysin gene and its use in identification of related Vibrio spp. from the Baltic Sea

A group of hemolytic Vibrio strains was isolated from surface water of the Baltic Sea in 1995. A typical representative strain, CH-291, was found to lyse washed human and animal erythrocytes. Hemolysis was found to be calcium-dependent and occurred over a temperature range from 25 to 37 degrees C. The hemolysin-encoding genes were identified by screening a genomic library of total DNA from strain CH-291. A cloned chromosomal DNA fragment of 15.6 kb conferred to Escherichia coli DH5alpha a hemolytic phenotype. Hybridization and sequence analysis showed the cloned sequence to be unique to these Baltic Sea Vibrio isolates and therefore provides a useful marker for their identification. Moreover, the cloned 15.6-kb DNA fragment possessed structural features typical for genetic islands, including a decreased GC content and a flanking cryptic insertion sequence element.