Six decades of changes in vascular hydrophyte and fish species in three plateau lakes in Yunnan, China

Biodiversity in the plateau lakes of Yunnan, China has decreased significantly over the past decades. To better understand this degradation, we analyzed the processes and characteristics of changes in vascular hydrophytes and fish species in three of Yunnan’s largest lakes (Dianchi, Erhai, and Fuxian). We reviewed primary literature reporting the occurrence of such species between the 1950s and 2000s. During this period, 46.3 % of native hydrophytes and 84.0 % of native fish species in Dianchi Lake had gone locally extinct, compared to 21.4 and 58.8 % in Erhai, and 11.8 and 41.7 % in Fuxian, respectively. In Dianchi alien species comprised 15.4 % of total hydrophytes and 87.5 % of total fish species, compared to 5.7 and 70.8 % in Erhai, and 11.8 and 65.0 % in Fuxian, respectively. The extinction of endemic fish species was particularly serious. The proportion of endemic fish species extinct was 90.0 % in Dianchi, 75.0 % in Erhai and 63.6 % in Fuxian. Homogenization of fish assemblages (calculated Jaccard indices) across the lakes increased during the study period in parallel with the extinction of endemics and introduction of alien species. Results showed that lacustrine conditions determined the observed changes of hydrophytes and fish species, likely reflecting anthropogenic disturbances associated with rapid economic development around the lakes. In a developing region like the plateau of Yunnan, which is rich in endemic freshwater species, the challenge is how to balance economic growth with habitat protection.     

Systematic revision of the freshwater snail Margarya Nevill, 1877 (Mollusca: Viviparidae) endemic to the ancient lakes of Yunnan,China, with description of new taxa

The systematics of the viviparid freshwater snail genus Margarya endemic to the ancient lakes of Yunnan, China, is revised based on comparative analyses of morphological features, including shell, operculum, radula, and genital anatomy, and molecular phylogenetic analyses of partial sequences of the mitochondrial 16S rDNA (16S) and cytochrome c oxidase subunit I (COI) genes, as well as the nuclear Internal Transcribed Spacer 2 (ITS2). The taxonomic utility of key anatomical and morphological features in this group is evaluated. The genus Margarya as delimited previously is split into three genera in order to retain monophyletic taxa: (1) Margarya s.s., consisting of four species, i.e. the type species Margarya melanioides plus Margarya francheti, Margarya oxytropoides, and Margarya monodi; (2) the previously introduced subgenus Tchangmargarya is elevated to an independent genus containing two species, Tchangmargarya yangtsunghaiensis and the new species T changmargarya multilabiata sp. nov. ; and (3) a new genus, A nularya gen. nov. , is described, also containing two species, i.e. Anularya mansuyi and Anularya bicostata. Molecular phylogenies based on analyses of three gene fragments have identical topologies, supporting the monophyly of these genera. The sister group of Margarya s.s. is Cipangopaludina, whereas the sister group of Anularya is Sinotaia; Tchangmargarya is sister to a clade containing all the aforementioned groups. Features of the operculum and the right male tentacle (penis) are particularly informative on the generic level, whereas shell and radular characters are especially useful to differentiate species. The phylogenetic relationships recovered here are consistent with orogenic patterns of the Yunnan Mountains. Changes in the river system and water area of ancient lakes caused by tectonic activities probably play an important role in speciation and shaping the current pattern of species distribution in Yunnan. © 2015 The Linnean Society of London     

Effects of eutrophication and temperature on Cyclotella rhomboideo‐elliptica Skuja,endemic diatom to China

An endemic diatom, Cyclotella rhomboideo‐elliptica Skuja, from the Yunnan Plateau, has been disappearing gradually from some lakes of the plateau. This study investigated the diatom's distribution in 30 lakes and documents long‐term population changes in the paleolimnological record of a deep lake, Lake Fuxian. Living cells of C. rhomboideo‐elliptica were found in five Yunnan Plateau lakes in 1957, but cells were restricted to Lake Fuxian in 2005. Its absolute abundance fluctuated from low to high to low. Our study suggests that nutrient concentrations correlate with C. rhomboideo‐elliptica's s abundance and survival. We infer that the disappearance of C. rhomboideo‐elliptica in some lakes may be due to increased nutrient concentrations and the species may be indicators of low nutrients. During the study, we also found that decreased in the diatoms average long axis length after the early 1990s. This morphological change was likely due to higher nutrient concentrations or to the increase in temperature, or a combination of the two.     

The extant Chaoborus assemblage can be assessed using subfossil mandibles

1. Assemblages of Chaoborus were examined in 80 thermally stratified southern central Canadian Shield lakes to explore whether subfossil mandibles could be useful in assemblage‐level studies of Chaoborus. 2. Chaoborus (Sayomyia) (probably Chaoborus punctipennis in this study region) and Chaoborus flavicans were the most common taxa recorded, while Chaoborus trivittatus was rarer. Chaoborus americanus was not recorded in subfossil assemblages, because no fishless lakes were included in this study. Chaoborus flavicans had higher relative abundances (%) in lakes with higher dissolved organic carbon (DOC), probably because of reduced fish predation in less transparent water. 3. Results from logistic regression indicate that patterns of presence/absence for Chaoborus mandibles in the study lakes were influenced primarily by hypolimnetic oxygen concentration, probably because of the presence or extent of a hypolimnetic refugium from fish predation. 4. Chaoborus species richness in lakes, derived from subfossil assemblages, did not differ significantly from species richness estimates derived from plankton sampling with a net. Patterns of dominance and coexistence [e.g. the widespread co‐occurrence of C. flavicans and C. (Sayomyia)] determined from subfossil assemblages agreed with previous studies of the contemporary living assemblage. 5. These results suggest that subfossil assemblages may be used as an alternative to nocturnal plankton sampling to carry out research on the community ecology of Chaoborus. 6. We propose a hierarchical conceptual model of assemblage‐level patterns of Chaoborus in temperate lakes. Chaoborus americanus dominates in fishless lakes, whereas in lakes with fish Chaoborus is typically absent where there is no anoxic hyplimnion. In lakes with anoxic strata, C. trivittatus tends to dominate in lakes with few fish; in the remaining lakes, C. flavicans and C. (Sayomyia) dominate, although C. flavicans is more relatively abundant in lakes with lower water clarity (higher DOC).     

云南不同高原湖泊噬藻体psbA基因多样性

【目的】噬藻体(cyanophage)广泛存在于自然水体生态系统中,通过侵染蓝藻进而调控蓝藻种群及群落结构,具有重要生态功能和生态地位,在控制蓝藻水华方面有巨大开发潜力。本研究旨在探究云南高原湖泊噬藻体psbA基因多样性,分析其系统进化地位,为深入了解高原湖泊生态功能、开发利用噬藻体资源奠定理论基础。【方法】以云南高原主要湖泊滇池、抚仙湖和星云湖等为研究对象,以psbA基因作为分子靶标,对湖泊水体中噬藻体遗传多样性进行研究。【结果】从不同湖泊中共获得100条环境噬藻体psbA基因序列,系统发育分析表明,湖泊的噬藻体psbA基因序列与中国东湖、中国东北稻田、日本稻田等淡水中的环境噬藻体psbA基因亲缘关系较近,与海洋环境噬藻体psbA基因亲缘关系较远;抚仙湖中的噬藻体psbA基因多样性高于滇池、星云湖和异龙湖中的噬藻体psbA基因多样性;云南高原湖泊中存在新的噬藻体类群;各湖泊秋冬季节噬藻体psbA基因遗传多样性差异不明显。【结论】云南主要高原湖泊噬藻体psbA基因遗传多样性高,与淡水环境噬藻体psbA基因亲缘关系较近,且存在独特的噬藻体类群。     

The birth of an endemic species flock: demographic history of the Bellamya group (Gastropoda,Viviparidae) in Lake Malawi

Changes in habitat stability may significantly shape evolutionary patterns and processes in ancient lakes. In the present study, we use a hierarchical combination of molecular phylogenetic and coalescent approaches to investigate the evolutionary history of the endemic species of the gastropod genus Bellamya in the African rift‐lake Malawi. By integrating our findings with reported palaeontological and palaeolimnological data, we demonstrate that all but one evolutionary lineage of the Pliocene Bellamya fauna in Lake Malawi became extinct. Coalescent analyses indicate that the modern radiation underwent both a sudden demographic and a spatial expansion after a genetic bottleneck. We argue that a reflooding of the lake after severe Pleistocene low stands offers a straightforward explanation for this pattern and may have triggered speciation processes in the modern endemic Bellamya radiation in Lake Malawi. © 2010 The Linnean Society of London, Biological Journal of the Linnean Society, 2011, 102 , 130–143.     

Ochthebius (s.str.) capicola (Coleoptera) re-discovered in the Cape Peninsula,South Africa

New distributional records and ecological observations are presented for the Cape endemic hydraenid Ochthebius capicola. Considered extinct on the Cape Peninsula, the species has been re-discovered at two adjacent locations as well as at a new site in Tsitsikamma National Park, Eastern Cape. New species associations are recorded, in conjunction with observations confirming this species' preference for algae-covered rock surfaces in the hypersaline pools of the supralittoral zone. Provisional internationally-endangered status for this species was examined but considered dependent on future data. It was considered likely that the beetle may be insufficiently recorded, due to its atypical habitat requirement. A synopsis of the taxonomic status of this species and Ochthebius rubripes is given. Notes on both species are provided, as well as a record of sympatric occurrence.     

Morphologically tortured: taxonomic placement of an Antarctic springtail (Collembola: Isotomidae) misguided by morphology and ecology

An endemic springtail from northern Victoria Land, Antarctica, was recently moved from Desoria to the new genus Chionobora, erected for a new species C. amila from lakes in the central highland plateau of Tasmania. This new combination for klovstadi was based on characters similar to both species (although not definitive) and an apparent preference for aquatic habitats. Here we show that neither of these inferences are valid. We sampled from two lake localities to obtain C. amila, and in doing so, we describe its habitat as riparian, not aquatic. We compared specimens of C. amila with klovstadi within a phylogeny using three genes (mtDNA COI, 18S rDNA, D1‐D5 of 28S rDNA) for 59 Isotominae terminals. We show that klovstadi is not closely related to the genus Chionobora that has closest affinities to the genus Isotomurus. As previously identified, klovstadi has no close affinities to any existing genus in Isotominae. Based on additional ecological, morphological and molecular evidence, we erect a new genus for klovstadi, Kaylathalia gen. n.     

A new species of Mesopropithecus (Primates, Palaeopropithecidae) from Northern Madagascar

We diagnose new subfossil specimens belonging to the extinct palaeopropithecid, Mesopropithecus,from several caves at the Ankarana massif in northern Madagascar. They include three partial crania with mandibles, and the first vertebrae, ribs, clavicle, pelvis, ulna, and hand and foot bones of Mesopropithecusever found. Several other postcranial elements are known for this northern variant of Mesopropithecusand for previously described species from central and southern Madagascar. The new materials cannot be accommodated in either currently recognized species of this genus and are,hereby, given the name Mesopropithecus dolichobrachion. M. dolichobrachionis the second new species of extinct subfossil lemur to be found in the caves of Ankarana. It is unlike the two previously described species of this genus primarily in its larger size, different limb proportions, and aspects of its long bone morphology. Most notable is the fact that this is the only species of Mesopropithecuswith the forelimb longer than the hind limb— hence the name, the “long-armed” Mesopropithecus.Various characteristics place M. dolichobrachionphenetically closest (of species belonging to Mesopropithecus)to Babakotia radofilai, Archaeoindris,and Palaeopropithecus.If these similarities are derived specializations rather than primitive for palaeopropithecids, a new generic name will be required.     

Paleoenvironment of Ankilitelo Cave (late Holocene, southwestern Madagascar): implications for the extinction of giant lemurs

Following human arrival, Madagascar suffered well-documented megafaunal extinctions and widespread deforestation. Although humans are widely considered to be the primary cause of the extinctions, the relative contributions of climate change and human activities to this ecological transformation remain uncertain. Reconstructing the habitats of the giant lemurs of Madagascar can provide key information for understanding the evolutionary mechanisms involved in their extinction. In this study, I present a faunal analysis of the subfossil assemblage from Ankilitelo Cave, southwestern Madagascar. This assemblage documents the latest known occurrence of five species of extinct giant lemur, in association with abundant well-preserved small mammal remains. I compared the small mammal fauna at Ankilitelo with 27 extant Malagasy mammal communities spanning the range of Madagascar's habitat types. Similarities in species composition between modern communities and Ankilitelo were assessed using cluster analysis. Ecological similarities were examined by assigning each species to dietary, locomotor, activity pattern, and body size categories. Multiple discriminant analysis was then used to classify Ankilitelo relative to modern habitat types in Madagascar, based on the ecological structure of the subfossil fauna. Results indicate that the habitat surrounding Ankilitelo during the late Holocene was similar to the succulent woodlands of modern southwestern Madagascar. This suggests that approximately 500 yr BP, these semi-arid habitats supported a subfossil lemur community that included the highly-suspensory Palaeopropithecus, and deliberate slow-climber Megaladapis, as well as Archaeolemur, Pachylemur, and Daubentonia robusta. In such environments, these giant lemurs would likely have been highly vulnerable to increasing human pressure in southwestern Madagascar.     

Ecological evaluation of local extinction: the case of two genera of endemic Mexican fish, Zoogoneticus and Skiffia

The Goodeidae is a family of endemic fish from central Mexico. Populations of several species are declining in the wild and two have been reported extinct; Skiffia francesae and Zoogoneticus tequila. Both species were native to just one locality in the Ameca basin. It is difficult to infer the causes of extinction, since limnological data from Teuchitlán prior to the extinction events are not available, and there are no replicate populations. As an alternative approach, we explored the potential links between key environmental variables and events of local extinction of any species in the two genera (four Skiffia spp. and two Zoogoneticus spp.). In 14 localities known to harbour populations of fish of at least one of the six focal species, we conducted limnological surveys in the rainy and in the dry season, and quantified population densities of endemic and introduced fish. In addition, we quantified the concentration of agricultural pollutants in water and mud samples taken from every locality in the dry season. We found that all the focal species face some conservation threat, but we also discovered an extremely small population of the reputedly extinct Zoogoneticus tequila; in contrast, Skiffia francesae was not found. Eutrophication and habitat fragmentation appear to be the main threats to the focal species, with habitat fragmentation exponentially reducing population size and driving populations into refuges where they face stochastic extinction.     

Responses of Metapopulation Dynamics to Two Different Kinds of Habitat Destruction Caused by Human Activities

Habitat destruction can be classified into instantaneous destruction and continuous destruction by the different ways of human destroying habitat. Previous studies, however, always focused on instantaneous destruction. In this study, we develop a universal model, Multi-time scale N-species model, to study and compare the responses of metapopulation dynamics to both kinds of habitat destruction. The model explores that: (1) under instantaneous habitat destruction, species extinction is determined by the proportion of habitat destruction (D) and the structure of metapopulation (q). When D>q, species will go extinct ranked from the best competitor to the worst. When D≤ q, no species will go extinct, but the equilibrium abundances of odd-ranked competitors will decrease, and the equilibrium abundances of even-ranked competitors will increase; (2) under continuous destruction, species extinction is dependent on the speed of habitat destruction and the metapopulation structure. The higher the speed of habitat destruction and the bigger q are, the earlier species go extinct. Usually, there are two possible mechanisms of species extinction: one is that all species go extinct collectively following complete destruction, and the other is that species go extinct in ranked competitive order from best to worst, and the survivals, if they exist, will go extinct collectively following complete destruction. The oscillation amplitudes of inferior competitors are so large as to increase the probability of stochastic extinction under instantaneous destruction. Therefore, it is relatively propitious for the persistence of rare species under slow and continuous destruction, especially when continuous destruction stops.     

Population modelling and genetics of a critically endangered Madagascan palm Tahina spectabilis

Madagascar is home to 208 indigenous palm species, almost all of them endemic and >80% of which are endangered. We undertook complete population census and sampling for genetic analysis of a relatively recently discovered giant fan palm, the Critically Endangered Tahina spectablis in 2008 and 2016. Our 2016 study included newly discovered populations and added to our genetic study. We incorporated these new populations into species distribution niche model (SDM) and projected these onto maps of the region. We developed population matrix models based on observed demographic data to model population change and predict the species vulnerability to extinction by undertaking population viability analysis (PVA). We investigated the potential conservation value of reintroduced planted populations within the species potential suitable habitat. We found that the population studied in 2008 had grown in size due to seedling regeneration but had declined in the number of reproductively mature plants, and we were able to estimate that the species reproduces and dies after approximately 70 years. Our models suggest that if the habitat where it resides continues to be protected the species is unlikely to go extinct due to inherent population decline and that it will likely experience significant population growth after approximately 80 years due to the reproductive and life cycle attributes of the species. The newly discovered populations contain more genetic diversity than the first discovered southern population which is genetically depauperate. The species appears to demonstrate a pattern of dispersal leading to isolated founder plants which may eventually lead to population development depending on local establishment opportunities. The conservation efforts currently put in place including the reintroduction of plants within the species potential suitable habitat if maintained are thought likely to enable the species to sustain itself but it remains vulnerable to anthropogenic impacts.     

Conservation status of <Emphasis Type="Italic">Prodontria</Emphasis> (Coleoptera: Scarabaeidae) species in New Zealand

The genus Prodontria (Scarabaeidae: Melolonthinae), which comprises 16 described species, is an endemic southern New Zealand genus occupying lowland and coastal habitats, inter-montane basins and alpine environments. Many of the species have a limited distribution and face potential threats from habitat change and predation. The only species to be formally protected is P. lewisii Broun, commonly known as the Cromwell Chafer, which is now restricted to a 81-ha reserve in Central Otago. One undescribed lowland species might be extinct as a result of habitat modification. The current status of Prodontria species, the known distribution of species and potential threats are discussed. An erratum to this article can be found at     

Dietary adaptations and palaeoecology of Lophialetidae (Mammalia,Tapiroidea) from the Eocene of the Erlian Basin,China: combined evidence from mesowear and stable isotope analyses

Lophialetidae is an extinct group of endemic Asiatic tapiroids that are widely distributed in the Eocene sediments of Asia. Schlosseria magister and Lophialetes expeditus are the most abundant species in this family. However, their dietary and ecological characteristics are largely unknown. For the first time, we reconstruct the palaeodiet and habitat of these two lophialetids using a combination of mesowear and stable carbon isotope analysis of fossil teeth excavated from the Erlian Basin, China. Mesowear analysis (n = 141) suggests that the dietary structure of S. magister and L. expeditus shifted from less to more abrasive diets from ~52 to ~42 Ma. Stable carbon isotope analysis (n = 137) suggests that the habitats of S. magister and L. expeditus became drier and/or more open through time. The dietary shifts of the two lophialetids are consistent with evident changes in habitat. The changes in the diet and habitat were probably related to global climate change during that time period. The gradual drop in global temperatures during the early–middle Eocene led to a drier and more open terrestrial ecosystem in the Erlian Basin, probably resulting in changes in floral composition of the environment inhabited by S. magister and L. expeditus. Hence, herbivores highly susceptible to vegetation modification had to develop new resource exploitation strategies to adapt to these changes. Schlosseria magister, considered to be the sister-group of L. expeditus and with a low level of ecological flexibility, was unable to adapt to the habitat changes finally becoming extinct at ~45 Ma.     

Patterns in taxonomic and functional diversity of lake phytoplankton

1. Patterns in phytoplankton diversity in lakes and their relationships with environmental gradients have been traditionally based on taxonomic analyses and indices, even though measures of functional diversity (FD) might be expected to be more responsive to such gradients. 2. We assessed the influence of water column physical structure, and other components of the overall environment, on lake phytoplankton diversity using two taxonomically based indices [species richness (S) and the Shannon index (H’)] and a FD index, to determine whether these different measures respond in similar ways to habitat structure. The study encompassed 45 lakes in Eastern Canada, within two lake districts [the Eastern Townships Region (ETR) and Laurentians Region (LR)] that vary in geology and landscape and in lake morphometry and chemistry. 3. Across all lakes, S and H’ were higher in lakes having greater vertical temperature heterogeneity and higher susceptibility to wind mixing. In addition, H’ declined with total phosphorus concentration. FD was only related to maximum lake depth, a variable that integrates many other habitat features. 4. Further insight into the factors affecting phytoplankton diversity was obtained by contrasting the two regions. The taxonomically based diversity measures differed little between the regions, while FD was higher in the ETR where more trait variants were present and more evenly distributed amongst species. Whereas factors driving S did not differ between the regions, we found region‐dependent patterns in the relationships of H’ and FD with maximum lake depth: both indices decreased with maximum depth in the region with lakes more exposed to wind (ETR) but increased in the more hilly landscape where lakes are more sheltered from wind mixing (LR). 5. Our study demonstrates that, for phytoplankton communities, a FD index can show simpler and stronger responses to environmental drivers than a taxonomically based index, while shedding further light onto the functional traits that are important in particular lake categories.     

Ancient lakes as hotspots of diversity: a morphological review of an endemic species flock of <Emphasis Type="Italic">Tylomelania</Emphasis> (Gastropoda: Cerithioidea: Pachychilidae) in the Malili lake system on Sulawesi,Indonesia

The viviparous freshwater gastropod Tylomelania (Caenogastropoda: Cerithioidea: Pachychilidae) endemic to the Indonesian island Sulawesi has radiated extensively in two ancient lake systems. We here present the first systematic species-level review of taxa in the five lakes of the Malili lake system, which contains the most diverse and best studied freshwater fauna on Sulawesi. Our results indicate a significantly higher diversity of Tylomelania in these lakes than previously perceived based on morphological evidence for delimiting the taxa. We describe nine new species, thus increasing the number of taxa known from the Malili lakes to 25. Tylomelania species are inhabiting all available substrates in the lakes, and the diversity of habitats is reflected in an unparalleled range of radula types in this closely related group. Several species show a high intraspecific variability in some characters, and their closer investigation will probably lead to the discovery of more cryptic species. As it is, this species flock on Sulawesi is among the largest freshwater mollusc radiations known. Since the Malili lake system also contains other large endemic species flocks of e.g. crustaceans and fishes, it is a major hotspot of freshwater biodiversity in Asia to become a conservation priority. Handling editor: K. Martens     

Drivers of extinction: the case of Azorean beetles

Oceanic islands host a disproportionately high fraction of endangered or recently extinct endemic species. We report on species extinctions among endemic Azorean beetles following 97% habitat loss since AD 1440. We infer extinctions from historical and contemporary records and examine the influence of three predictors: geographical range, habitat specialization and body size. Of 55 endemic beetle species investigated (out of 63), seven can be considered extinct. Single-island endemics (SIEs) were more prone to extinction than multi-island endemics. Within SIEs restricted to native habitat, larger species were more extinction-prone. We thus show a hierarchical path to extinction in Azorean beetles: species with small geographical range face extinction first, with the larger bodied ones being the most threatened. Our study provides a clear warning of the impact of habitat loss on island endemic biotas.     

Nematodes from saline and freshwater lakes of the Vestfold Hills,East Antarctica,including the description of <Emphasis Type="Italic">Hypodontolaimus antarcticus</Emphasis> sp. n.

The invertebrate fauna of many Antarctic ice-free areas, even those close to permanent research stations, can be poorly known. Here we describe some nematodes from freshwater and saline, marine-derived lakes of the Vestfold Hills, East Antarctica. The freshwater lakes contained the widespread East Antarctic endemic species, Plectus frigophilus Kirjanova, 1958. The saline lakes were inhabited by two recently described species, Halomonhystera halophila Andrássy, 2006 and Halomonhystera continentalis Andrássy, 2006, and by a new species described in this report, Hypodontolaimus antarcticus sp. n. Originally marine but now brackish Highway Lake contained a nematode fauna with both freshwater and marine-derived components. The nematode fauna of Antarctica now consists of 54 named species, 22 of which are found in East Antarctica.