Annual variation in biomass and the community structure of crustacean zooplankton over 5 years in Lake Toya, Japan

The biomass and population dynamics of crustacean zooplankton were determined in oligotrophic Lake Toya in Japan over 5 years from May 1992 to May 1997. In 1992 and 1993, zooplankton biomass was up to 4.3 g dry weight m^?2, whereas it decreased to <1 g dry weight m^?2 after 1994. This extreme change in biomass was associated with the succession of dominant species from larger ones, such as Daphnia longispina and Cyclops strenuus (s. lat.), to smaller ones, such as Eubosmina tanakai and Bosmina longirostris. Consequently, this biomass change seemed to cause an increase in the chlorophyll a concentration in the euphotic zone and a decline in lake transparency. Because the birth rates of the dominant species were somewhat higher after 1994, the decline in the populations of larger crustaceans seemed to depend more on their rate of death rather than rate of birth, and this higher death rate is not considered to be attributed to food shortage. Although these results strongly suggest a top-down cascading effect of fish predation upon crustaceans, annual catches of two commercially important planktivorous fish species have also decreased in the lake, coincidentally with decreases in zooplankton biomass. This may be attributable to fishing regulations that prohibit catching smaller fish, implying that such smaller fish affect zooplankton and phytoplankton, as well as lake transparency.     

Radical changes in the Wadden Sea fauna and flora over the last 2,000 years

Humans have interacted with the Wadden Sea since its origin 7,500 years ago. However, exploitation, habitat alteration and pollution have strongly increased since the Middle Ages, affecting abundance and distribution of many marine mammals, birds, fish, invertebrates and plants. Large whales and some large birds disappeared more than 500 years ago. Most small whales, seals, birds, large fish and oysters were severely reduced by the late 19th and early 20th centuries, leading to the collapse of several traditional fisheries. In the 20th century, conservation efforts have enabled some breeding birds and seals to recover. But other species declined further due to continuing exploitation, habitat destruction, pollution and eutrophication. Moreover, complex three-dimensional habitats such as oyster banks, Sabellaria reefs and subtidal eelgrass beds have been lost completely. In contrast, several opportunistic species such as gulls, polychaetes, green algae and exotic invaders increased during the 20th century. Taken together, multiple human impacts have caused dramatic losses of large predators and habitat-building species in the Wadden Sea over the last 500 years. Although still of high natural value and global importance, the Wadden Sea is a fundamentally changed ecosystem. On the other hand, reduced hunting pressure, increased habitat protection and reduced river pollution have enabled the recent recovery of several species and an increase in environmental quality. These successes, together with a historical vision of what was once possible, should guide current and future conservation, restoration and management efforts towards a more sustainable interaction between man and the sea.     

Adaptive responses in resurgent Lake Victoria cichlids over the past 30 years

Textbook examples of adaptive radiation like the Galapagos finches and the East-African cichlids form a subject of major interest in evolutionary biology. Many of these species often show rapid morphological changes in response to a perturbed environment. The dramatic ecological changes in Lake Victoria during the past three decades, e.g. Nile perch predation and eutrophication, provide a unique opportunity to study environmental effects on cichlid morphology. Preliminary research has revealed that the lake’s haplochromines tend to be extremely plastic and sensitive to these environmental changes. So far, long-term ecomorphological studies at short-term intervals are extremely rare. In this study, we examined morphological changes over a 30 year period in six haplochromine species. Geometric morphometric analyses at intervals of approximately 3 years revealed adaptive responses. Three out of four resurgent haplochromines had a smaller head surface/caudal peduncle area (HS/CPA) ratio during the upsurge of the predatory Nile perch. During the same period, all four resurgent species had a larger cheek depth and a smaller eye size. The smaller HS/CPA ratio and larger cheek depth are likely to be adaptive responses to a high predation pressure and a diet shift to larger prey. The smaller eye size seems to be the result of a trade off between the eyes and other morphological structures in the smaller head of these species. Interestingly, the direction of the morphological changes was different between the four resurgent cichlid species and two species that became extremely rare or even may have gone extinct. The HS/CPA ratio increased in the extinct species where it decreased in the resurgent species. This study suggests that predation is a major driver of these morphological changes, which may be due to either phenotypic plasticity or adaptive changes.     

Floristic composition and diversity changes over 60 years in eastern mulga communities of south central Queensland,Australia

Botanical surveys from prior to 1949 documented the plant species composition of the mulga (Acacia aneura) communities in the eastern Mulga Lands Bioregion of Queensland, Australia. These surveys recorded 282 vascular plant species including 268 natives and 14 exotics. Since 1949, mulga communities have experienced considerable modification through continuous grazing by domestic sheep and cattle even during drought periods and extensive vegetation clearance. To increase our knowledge on floristic composition and diversity change over this time, floristic data were recollected from mulga communities in the same region between 2007 and 2010 using a more systematic procedure. These surveys recorded 292 vascular plant species including 269 natives and 23 exotics. Species richness and composition within five life forms: tree, shrub, vine, forb and graminoid were compared between the recent survey data and the historical survey data. The majority of native plant species were either in the forb (45.4% of total native species) or graminoid (25.7% of total native species) life forms over the 60-year period. There was no significant difference in species richness between the historical and recent surveys within tree or shrub life forms, but there were differences in species richness in vine, forb and graminoid life forms over time. Similarities in native species between the historical and recent surveys were high. Sorensen Similarity Indices (ISS) were: 0.77 at species level, 0.84 at genus level and 0.87 at family level. In contrast, the similarity indices for exotic species was low (0.59) for species and genera (0.61), but high for families (0.86). More exotic species were recorded recently than historically. Among these, buffel grass (Pennisetum ciliare) and colocynth (Citrullus colocynthis) were more commonly encountered than other exotic species in the eastern mulga communities of south central Queensland, Australia.     

Analysis of changes over 44 years in the phytoplankton of Lake Võrtsjärv (Estonia): the effect of nutrients,climate and the investigator on phytoplankton-based water quality indices

We analysed long-term changes in phytoplankton composition in relation to hydrological, meteorological and nutrient loading data in the large (270 km²) shallow (mean depth 2.8 m) Lake Võrtsjärv. Nutrient loads to the lake were heavy in the 1970s and 1980s and decreased considerably thereafter. The average nutrient concentrations for 1985–2004 (1.6 mg l^?1 of total nitrogen and 53 μg l^?1 of total phosphorus) characterize the lake as a eutrophic water body. All four calculated taxonomic indices showed a unidirectional deterioration of the lake’s ecological status, despite reduced concentrations of nutrients. We focused our analysis on the PTSI index, which revealed a stepwise change between the years 1977 and 1979 that coincided with a large increase in water level, but also with a change of investigator. After correcting input data for possible investigator-induced differences, the step change remained because it was caused by major changes in the whole phytoplankton community. The previous dominant Planktolyngbya limnetica was replaced by two species of seasonally altering Limnothrix. Among phytoplankton functional groups, there was a decrease in all groups comprising small-sized phytoplankton species, such as X1, E, F, J, N and an increase in S1 and H1, both represented by filamentous cyanobacteria. Our results suggest a non-linear response of phytoplankton to changing nutrient loadings, and that the change observed between 1977 and 1979 was a regime shift triggered by water level change. High shade tolerance of the new dominants, and their ability to create shade, obviously stabilized the new status making it resistant to restoration efforts.     

Eight years of internal phosphorus loading and changes in the sediment phosphorus profile of Lake Søbygaard,Denmark

During each of the first 8 years following an 80–90% reduction in external phosphorus loading of shallow, hypertrophic Lake Søbygaard, Denmark in 1982, phosphorus retention was found to be negative. Phosphorus release mainly occurred from April to October, net retention being close to zero during winter. Net internal phosphorus loading was 8 g P m^–2 y^–1 in 1983 and slowly decreased to 2 g P m^–2 y^–1 in 1990, mainly because of decreasing sediment phosphorus release during late summer and autumn. The high net release of phosphorus from Lake Søbygaard sediment is attributable to a very high phosphorus concentration and to a high transport rate in the sediment caused by bioturbation and gas ebullition. Sediment phosphorus concentration mainly decreased at a depth of 5 to 20 cm, involving sediment layers down to 23 cm. Maximum sediment phosphorus concentration, which was 11.3 mg P g^–1 dw at a depth of 14–16 cm in 1985, decreased to 8.6 mg P g^–1 dw at a depth of 16–18 cm in 1991. Phosphorus fractionation revealed that phosphorus release was accompanied by a decrease in NH₄Cl-P + NaOH-P and organic phosphorus fractions. HCl-P increased at all sediment depths. The Fe:P ratio in the superficial layer stabilized at approximately 10. Net phosphorus release can be expected to continue for another decade at the present release rate, before an Fe:P ratio of 10 will be reached in the sediment layers from which phosphorus is now being released.     

Ostracod-based environmental reconstruction over the last 8,400 years of Nam Co Lake on the Tibetan plateau

From a 332-cm long lacustrine core taken at 60 m water depth and 25 surface sediment samples taken at different water depth sites in Nam Co lake (4,718 m a.s.l.) in the middle-south part of the Tibetan Plateau, we identified nine species of ostracods (Crustacea: Ostracoda) belonging to six genera. Using lithological data, auto-ecological information of the recovered taxa and an ostracod-based transfer function for water depth reconstruction, we distinguished three main environmental stages over the past 8,400 years: during Stage I (8,400–6,800 yr BP), the climate changed from warm-humid to cold-humid, and eventually to cold-arid. The water depth of the site was much lower than today and changed from an estimated 50 to 20–30 m. During Stage II (6,800–2,900 yr BP), environmental conditions were again warm-humid, turning into a cold-arid episode. The lake water depth initially stayed much shallower than today, but then gradually deepened to around 50 m. At the earlier period of Stage III (2,900 yr BP–present), the climate became again warm-humid from cold-arid status. There was a cold-dry event between 1,700 and 1,500 yr BP, which intensified afterward while the surface run off weakened. Early in this stage, lake depth decreased slightly, but then it continuously deepened to 60 m. Our results revealed that central Tibet experienced wavily warm toward tendency in early Holocene, a shift from warm-humid to cold-dry conditions in the middle Holocene, and from warm-humid to cold-dry conditions in the late Holocene. They also show that ostracod assemblages are not only indicative of cold-warm conditions, but are also usable to imply the dry–wet status of a lake area by the inferring water depth variations. Finally, this study provides baseline data on (natural) climate change in this mountain region against which to compare global change impacts.     

Spatial pattern dynamics over 10 years in a conifer/broadleaved forest,northern Japan

The present study investigated stand dynamics during 10-year period in a conifer/broadleaved mixed forest in Hokkaido, northern Japan, focusing on spatially dependent recruitment, mortality and growth of two growth-form groups, deciduous broadleaved species and the dominant evergreen conifer Abies sachalinensis. The stand-level basal area was maintained over the 10-year period, while a compositional equilibrium at the individual species level was not confirmed. Univariate and bivariate spatial analyses revealed clustering of many of the constituent species. The absence of single-species patches suggested an ambiguous mosaic formed by co-occurrence of Abies and broadleaved trees. The trend towards an aggregated distribution of Abies and broadleaved trees was caused by spatially dependent recruitment rather than mortality. New recruits of broadleaved species were spatially associated with surviving broadleaved trees, while this was not the case for Abies. The degree of competitive effects on growth was not consistent over the 10-year period. Abies showed between-groups competition, but not within-group competition. In contrast, we found asymmetric competitions between the broadleaved trees. Our results suggest that Abies is not sufficiently competitively dominant to exclude broadleaved trees, and that the co-occurrence of the two growth-form groups might be maintained.     

Succession of aquatic macrophytes in the Modern Yellow River Delta after 150 years of alluviation

This study evaluated the succession process of aquatic macrophytes after 150 years of alluviation in the Modern Yellow River Delta, China, and identified the roles of various environmental parameters that regulate vegetation succession. From 2007 to 2008, 214 quadrats were surveyed and 19 environmental parameters were measured, including elevation, plot distance from the seashore, 10 water parameters, and 7 soil parameters. Forty-six aquatic macrophytes belonging to 20 families and 34 genera were identified across the entire delta. Emergent and submerged plants were the most frequent species, accounting for 58.7 and 34.8 % of all species, respectively. Detrended canonical correspondence analysis showed that the presence of aquatic macrophytes in this delta was primarily regulated by water salinity, soil salinity, and distance from the seashore, followed by nutrient concentrations (e.g., NH₄ ⁺, total soil N and PO₄ ^? of water). Salinity-tolerant species (e.g., Ruppia maritima, Phragmites australis, and Typha angustifolia) tended to be widely distributed across the entire delta. In contrast, salinity-sensitive species (e.g., Ceratophyllum demersum, Hydrilla verticillata, and Potamogeton malaianus) tended to be distributed in areas at the early stages of succession, which were relatively distant from the shore. Moreover, this study also confirmed that species richness and diversity were negatively correlated with water and soil salinity, which in turn were negatively correlated with plot distance from the shore. These data indicate that the primary drivers of aquatic macrophyte succession in this delta are water and soil salinity. The information assimilated here is used to propose management practices for the protection of aquatic macrophytes in the Yellow River Delta.     

Mutagenicity of bi-, tri- and tetra-cyclic aromatic hydrocarbons in the “taped-plate assay” and in the conventional Salmonella mutagenicity assay

Aromatic hydrocarbons in the range of 1–4 nuclear rings were examined for mutagenicity in the so-called “taped-plate assay”. This modification of the Ames assay is particularly equipped for the detection of volatile mutagens. Of the many compounds tested only phenanthrene, pyrene, benzo[c]phenanthrene and benzoacenaphthylene were positive in this assay. The present data underline the exceptional behaviour of fluoranthene by being a rather potent bacterial mutagen with a volatile nature (as found in a previous study).     

Nutrient fluxes and water quality in the drainage network of the Scheldt basin over the last 50 years

and use and urban activity in the catchment of the Scheldt river system have deeply changed during the last 50 years, modifying in turn the water quality of the drainage network and the fluxes of nutrient transferred to the estuary and to the sea. Based on the RIVERSTRAHLER model, developed for establishing the link between the biogeochemical functioning of large river systems and the constraints set by the meteorology, the morphology of the drainage network and the human activity in the watershed, we reassembled the data available to document these constraints in the Scheldt basin since the last half of the XXth century and we used them to reconstruct the variations of nutrient and oxygen concentrations at the outlet of the Scheldt drainage network. We compared the results with the water quality data at the entrance of the estuarine zone available since the 1960s. Both model results and observational data show a very severe deterioration of water quality (with deep oxygen depletion) in the beginning of the 1960s, while a clear trend to improvement is apparent since the late 1980s. The budget of nutrient loadings from the watershed, retention within the drainage network and delivery to the estuarine zone is established on an annual basis for the 50 last years. The yearly fluxes of nutrient delivered by the river to the estuary and the sea show a severe depletion of silica with respect to nitrogen compared with the requirements of diatoms, and a clear shift from the early 1990s from nitrogen to phosphorus potential limitation. Seasonal variations of nutrient delivery are however much more pronounced for nitrogen, with much less inputs during the dry seasons, while phosphorus inputs, mainly from point sources are more constant, so that nitrogen limitation can still occur during summer. Compared with similar budget estimations carried out for the Seine river system, the Scheldt basin, in spite of its much higher population density, does not deliver higher specific fluxes of nutrient (presently about 2000 kgN/km²/yr, 80 kgP/km²/yr and 1000 kgSi/km²/yr), owing to very efficient processes of nutrient retention.     

Grain of environment explains variation in the strength of genotype × environment interaction

Theory predicts that genetic variation in phenotypic plasticity (genotype × environment interaction or G × E) should be eroded by selection acting across environments. However, it appears that G × E is often maintained under selection, although not universally. This variation in the presence and strength of G × E requires explanation. Here I ask whether the explanation may lie in the grain of the environment at which G × E is expressed. The grain (or grain size) of the environment refers to the scale of environmental heterogeneity relative to generation time – that is, relative to the window of operation of selection – with higher rates of heterogeneity occurring in finer‐grained environments. The hypothesis that the grain of the environment explains variation in the expression of G × E encapsulates variation in the power of selection to shape reaction norms: selection should be able to erode G × E in fine‐grained environments but lose its power as the grain becomes coarser. I survey studies of G × E in sexual traits and demonstrate that the strength of G × E varies with the grain of the environment across which it is expressed, with G × E being stronger in coarser‐grained environments. This result elucidates when G × E is most likely to be sustained in the reaction norms of fitness‐related traits and when its evolutionary consequences will be most pronounced.     

Degradation of polycyclic aromatic hydrocarbons and long chain alkanes at 6070 °C by Thermus and Bacillus spp

Although polycyclic aromatic hydrocarbons (PAH) and alkanesare biodegradable at ambient temperature, in some cases low bioavailabilities are thereason for slow biodegradation. Considerably higher mass transfer rates and PAH solubilities and hence bioavailabilities can be obtained at higher temperatures. Mixed and pure cultures of aerobic, extreme thermophilic microorganisms (Bacillus spp., Thermus sp.) were used to degrade PAH compounds and PAH/alkane mixtures at 65 °C. The microorganismsused grew on hydrocarbons as sole carbon and energy source. Optimal growthtemperatures were in the range of 60–70 °C at pH values of 6–7. The conversion of PAH with 3–5 rings (acenaphthene, fluoranthene, pyrene, benzo[e]pyrene) was demonstrated. Efficient PAH biodegradation required a second, degradable liquid phase. Thermus brockii Hamburg metabolized up to 40 mg (l h)^-1 pyrene and 1000 mg(1 h)^-1 hexadecane at 70 °C. Specific growth rates of 0.43 h^-1 were measured for this strain with hexadecane/pyrene mixtures as the sole carbon and energy source in a 2-liter stirred bioreactor. About 0.7 g cell dry weight were formed from 1 g hydrocarbon. The experiments demonstrate the feasibility and efficiency of extreme thermophilic PAH and alkane biodegradation.     

Using liquid chromatography–tandem mass spectrometry to quantify monohydroxylated metabolites of polycyclic aromatic hydrocarbons in urine

We present an assay which employs enzyme digestion and solid phase extraction followed by liquid chromatography–tandem mass spectrometry to simultaneously quantify 16 hydroxylated polycyclic aromatic hydrocarbons (OHPAHs) in 3-ml samples of urine. The analytes consisted of 2-, 3-, and 4-ring OHPAHs, namely, 1- and 2-hydroxynaphthalene (1- and 2-OHNAP), 2-hydroxyfluorine (2-OHFLU), 1-, 2-, 3-, 4-, and 9-hydroxyphenanthrene (1-, 2-, 3-, 4-, and 9-OHPHE), 1-hydroxypyrene (1-OHPYR), 1- and 2-hydroxybenzo(a)anthracene (1- and 2-OHBAA), 3- and 6-hydroxychrysene (3- and 6-OHCHR) and 3-, 7-, and 9-hydroxybenzo(a)pyrene (3-, 7-, and 9-OHBAP). The method was validated using urine samples from steel workers and control subjects. The coefficients of variation of the method for the particular analytes were between 7% and 27% and the limits of quantitation were between 0.002 and 0.010 μg/l urine. The 2- and 3-ring OHPAHs were easily quantified in all subjects. However, 1-OHPYR was the only representative of the 4- and 5-ring metabolites that could be quantified. Pairwise correlations showed that all OHPAHs were highly correlated with each other (0.553 ≤ r ≤ 0.910) and with 1-OHPYR (0.614 ≤ r ≤ 0.910), the metabolite most widely accepted as a short-term biomarker of exposure to PAHs. The analyte, 2-OHNAP exhibited the lowest pairwise correlations with the other OHPAHs (0.542 ≤ r ≤ 0.628), presumably due to confounding by smoking. Metabolites of phenanthrene, an abundant PAH and the smallest to possess a bay region, are promising OHPAHs for characterizing both exposures to PAHs and the various metabolic pathways.     

Temporal dynamics and resilience of fine litterfall in relation to typhoon disturbances over 14 years in an old-growth lucidophyllous forest in southwestern Japan

We examined fine litterfall fluctuations on a seasonal and annual scale for 14 years (1992–2005) in a 1.2-ha plot in an old-growth lucidophyllous (evergreen broad-leaved) forest within the Aya Research Site, southwestern Japan. The average total litterfall input was 6.32 Mg ha^–1, of which leaf litter accounted for 60% of the total. Two high-impact typhoons struck the study area in 1993 (T9313) and 2004 (T0416) during the observation period; however, the subsequent pattern of litterfall after disturbance was different between the two typhoons. T9313 disturbance caused a reduction of biomass (ca. 10% of basal area (BA)) and a sharp decrease in litterfall input following a massive input in 1993. On the other hand, T0416 caused a minor decline in litterfall input, accompanied by a relatively small reduction of BA (5.2% of the 2001 BA). In spite of large fluctuations, litterfall input increased year by year after the T9313 disturbance. In 2000, 7 years after T9313, leaf input showed no significant differences and recorded more than 90% of pre-T9313 levels. Re-leafing from typhoon survivors may play an important role in the recovery of litterfall input in this forest. This study demonstrated how one high-impact typhoon can alter the temporal fluctuations in fine litterfall in lucidophyllous forest ecosystems.     

Estimates of annual survival,growth, and recruitment of a white-tailed ptarmigan population in Colorado over 43 years

Long-term datasets for high-elevation species are rare, and considerable uncertainty exists in understanding how high-elevation populations have responded to recent climate warming. We present estimates of demographic vital rates from a 43-year population study of white-tailed ptarmigan (Lagopus leucura), a species endemic to alpine habitats in western North America. We used capture-recapture models to estimate annual rates of apparent survival, population growth, and recruitment for breeding-age ptarmigan, and we fit winter weather covariates to models in an attempt to explain annual variation. There were no trends in survival over the study period but there was strong support for age and sex effects. The average rate of annual growth suggests a relatively stable breeding-age population ( \( \bar{\lambda } \)  = 1.036), but there was considerable variation between years for both population growth and recruitment rates. Winter weather covariates only explained a small amount of variation in female survival and were not an important predictor of male survival. Cumulative winter precipitation was found to have a quadratic effect on female survival, with survival being highest during years of average precipitation. Cumulative winter precipitation was positively correlated with population growth and recruitment rates, although this covariate only explained a small amount of annual variation in these rates and there was considerable uncertainty among the models tested. Our results provide evidence for an alpine-endemic population that has not experienced extirpation or drastic declines. However, more information is needed to understand risks and vulnerabilities of warming effects on juveniles as our analysis was confined to determination of vital rates for breeding-age birds.     

Assessment of ecosystem health during the past 40 years for Lake Taihu in the Yangtze River Delta,China

An assessment of the ecosystem health of Lake Taihu in eastern China from 1960 to 2005 was conducted using separate and aggregated chemical and biological indicators. The chemical oxygen demand, the total nitrogen, total inorganic nitrogen and total phosphorus concentrations, and the molar ratio of TN to TP (N/P) have all significantly increased (P < 0.05) since 1980. The trophic state index increased from 35.0 in 1960 to >60.0 in 1990, confirming that Lake Taihu changed from being oligotrophic to being eutrophic. These changes in water quality have led to corresponding changes in species composition and in the densities and biomasses of many aquatic species. Algal blooms have occurred frequently since the late 1980s, leading to the dominance of small zooplankton and benthic invertebrates. About 41 fish, 65 zooplankton and 16 macrophyte species were estimated to have disappeared from the lake since the late 1980s. Buffer capacity increased for phytoplankton and zooplankton but decreased for zoobenthos. These results suggest that the Lake Taihu ecosystem was in better health in 1960, and has deteriorated since 1980.     

Changes in the lichen biota of the Lions Rump area,King George Island,Antarctica, over the last 20 years

Climate changes observed in recent years in the maritime Antarctic have affected the tundra vegetation, including plant communities in which lichens are a dominant component. The results of comparative studies (1988 and 1990 vs. 2007 and 2008) on the dynamics of the lichen biota within the Antarctic Specially Protected Area No. 151 (King George Island, Antarctica) minimally influenced by human impact, are presented. This long-term experiment is aimed at determining the trends and rate of changes on lichen biota induced by climate warming and rapid deglaciation. The most significant changes affecting the lichen biota have taken place in the forefield of a glacier and on the young moraines where in the second period of studies three species (Polyblastia gothica, Thelenella kerguelena, Thelocarpon cyaneum) were not refound. There was also a reduction in the number of other sites for some species (e.g. Leptogium puberulum, Staurothelle gelida) caused by substrate desiccation. On the other hand, there was an increase in the range of pioneering species (e.g. Bacidia chrysocolla, Caloplaca johnstonii, Candelariella aurella, Lecanora dispersa) on young moraines recently uncovered by the retreating glacier. The smallest changes were observed on the cliff rocks near penguin colonies.     

Accomplishments and impact of the NGO,Island Conservation,over 15 years (1994–2009)

Improvements in biodiversity conservation are hampered by the lack of reporting on the effectiveness of conservation techniques and the organizations that implement them. Here we summarize the accomplishments and potential impact of the non-governmental organization, Island Conservation, which eradicates damaging invasive vertebrates from islands. Island Conservation has removed 54 populations of 10 invasive vertebrates from 35 islands totaling over 520 km². These actions helped protect 233 populations of 181 insular endemic species and subspecies of plants and vertebrates and 258 populations of 54 species and subspecies of seabirds from the threat of local and global extinction. There were no reinvasions. One eradication attempt failed. These conservation actions and their apparent biodiversity impact demonstrate the potential of private organizations to protect biodiversity by eradicating invasive species from islands.     

Decline in seminal quality in Indian men over the last 37 years

Background

Since the first report of a decline in semen quality in 1974, there have been several reports of similar declines across populations. Despite some scattered reports of declining semen quality in the Indian sub-continent, comprehensive studies analyzing semen quality over the last few decades have not been undertaken. We undertook the present study to investigate the temporal trend in semen parameters in Indian populations over a period of 37 years (1979–2016).

Methods

Publications providing semen analysis details for fertile and infertile men from the Indian sub-continent were collected by a thorough literature search. Semen quality data for 6466 normal fertile or presumptive normal men (from 119 studies/data sets) and 7020 infertile men (from 63 studies/data sets) published between 1979 and 2016 were retrieved. We undertook systematic review and quantitative analysis of mean sperm count, motility, normal morphology and other available parameters. Data were analyzed to estimate semen parameters reference values for Indian men and to assess temporal trends in infertile, fertile and all subjects.

Results

Seminal quality shows a decreasing temporal trend and the decrease is higher in infertile than fertile males. In pooled analysis for all individuals, significant (p?<?0.05 or?<?0.001) declines in sperm concentration and normal morphology are observed; however, isolated analysis for each group shows declines without statistical significance. The mean (± SD) semen volume, sperm concentration, total motility, rapid linear progressive motility, normal sperm morphology and sperm viability for Indian fertile men are 2.88?±?0.77 ml, 81.08?±?29.21 million/ml, 66.37?±?10.95%, 52.64?±?15.78%, 56.68?±?20.23% and 72.63?±?8.31%, respectively, whereas in infertile these are 3.07?±?1.27 ml, 37.94?±?26.41 million/ml, 40.22?±?13.76%, 26.79?±?15.47%, 36.41?±?21.66% and 55.25?±?11.99%, respectively. The mean seminal parameter values were significantly lower (p?<?0.001) in infertile as compared to fertile men, except semen volume.

Conclusions

Semen parameters in Indian men have declined with time and the deterioration is quantitatively higher in the infertile group. The study also provides reference values for semen parameters in Indian men.