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వాల్యూమ్ 6, సమస్య 4 (2018)

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Biodiversity Congress 2017: Seed size, storage and germination requirements can shape plant community structure in arid Arabian deserts

Ali El-Keblawy, Hatem A Shabana and Teresa Navarro

Background & Aim: Seed size (mass) and growth forms can affect dispersal distance, position of diaspora storage and consequently affect seedling establishment, growth, and survival and can shape community structure. Fewer studies assessed the relationship between seed size and germination level among different growth forms. Here, we assessed the impact of plant growth form, seed storage, and seed size and masses on seed dormancy, and light and temperature requirements during germination of 23 desert plants with aerial seed bank. Location: Northern Emirates of the United Arab Emirates (UAE) was the setting taken for this study. Methods: Seeds of 23 species with aerial seed bank, representing different growth forms (6 herbaceous, 11 small shrubs and 6 trees) were collected from natural habitats of the arid deserts of the UAE. Average seed mass and size were determined for each species. Fresh seeds, and those stored both in room temperatures for 9 months were germinated at daily night/day temperature regimes of 15/25°C, 20/30°C and 25/35°C in both continuous darkness and alternating light/darkness. Pearson correlation coefficients were used to assess the significance of the relationship between seed mass and seed size with final germination, relative light germination (RLG) and germination rate index (GRI) for each growth form at each temperature and light condition. Results: Trees and shrubs have significantly larger, heavier seeds that are characterized with higher dormancy, compared to herbaceous plants. Germination at all storage conditions was positively photoblastic in herbaceous plant, but was neutrally photoblastic in both shrubs and trees. Field storage enhanced light germination in trees, but not in shrubs and herbs. The relationships between both seed size and mass and final germination at all light and temperature conditions was positive in herbaceous, but negative in shrubby species. The relationship between seed size and LGI was significantly positive in shrubs; but was significantly negative in herbs and trees. GRI was greater for bigger seeds of herbs, but the reverse was true for seeds of trees. Conclusion: Seed size and storage, and light requirement during germination of species belonging to different growth forms could explain their distribution in the community and consequently could help explain community structure and composition.
Seed dormancy is an adaptation of the many plant species in unpredictable heterogeneous environments, like arid desert. Dormancy advantage, delay seed germination until the arrival of favourable conditions that allow seedling establishment and minimize seedling mortality. Light, temperature and moisture are the foremost important factors that determine germination time and place in desert environments. Herbaceous plants have smaller and lighter seeds.Room temperature storage improved final germination. Germination of herbaceous and trees species was greater than that of shrubby plants. Germination in light was greater than darkly . Unlike light, temperature had limited role in seed germination .The relationship between seed size and LGI was positive in shrubs; but was negative in herbs and trees. GRI was greater for bigger seeds of herbs and shrubs. But in trees the greater was for little seeds Generally, shrubs and trees attained lower germination than herbaceous plants. this means that smaller seeds germinate far more than larger seeds. Smaller seeds of herbs have greater chance for dispersal with winds than larger seeds of the opposite growth forms and explore new favourable condition, especially within the unpredictable desert habitats. In herbaceous plants, the small-seeded herbs contribute their seeds to soil seed bank, but large seeded invest more in their regeneration.Herbs with small seeds distribute the danger along time and retain a fraction of un-germinated seeds for the longer term . Small-seeded herbs required more light for germination, but large-seeded ones germinated better darkly . Small seeds buried too deep within the soil avoid possible fatal germination. Small seeds have little resources that limit seedling emerge from a depth deeper than superficial soils.The more food reserves of larger seeds enable them to emerge even from a deeper soil. Germination of larger seeds at deeper soil ensures that they're going to be closer to the wet soil, which might increase the prospect of the seedling establishment. In shrubs, large-seeded species germinate but small-seeded ones. Fewer large seeds that would germinate do this mainly in light. Canopy of small shrubs are dense, rounded and laid over the bottom so heavier larger seeds are expected to be retained under the canopies would expose them to lower R:FR (red/far-red) ratio and consequently end in lower germination, especially in dark. Larger seeds of shrubby plants should be dispersed away from their canopies. the higher chance of small seed for germination under the canopies of nurse plants to supply shade protect them from direct thermal radiation. The reduction of germination of the larger seeds under the cover would scale back inter- and intraspecific competition. Large seeds that might germinate faraway from canopies can produce bigger seedlings that migh adapt to dryness of exposed soils. In trees, species with large-seeded trees germinated more in dark, but small-seeded ones germinated better in light. The result might be explained consistent with the mode of dispersal of the studied tree species. Heavy diaspore unit which dispersed primarily by gravity germinated under the canopies. Endozoochorous species would disperse within the feces of grazing animals and consequently germinate in darkness; either within the feces or when feces buried in soil.When large seeds germinated under tree canopies they're going to produce larger seedlings that would compete with the maternal trees within the future . Field storage didn’t improve germination of seeds of herbaceous and shrubby plants, but improved it in seeds of trees. Under field condition, physical dormancy of the many species is weakened by sand scarification. Diurnal fluctuations in day and night moisture and temperatures could end in break down physical dormancy.
 

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Biodiversity Congress 2017: Biomonitoring of selected freshwater bodies using diatoms as ecological indicators

R U Sawaiker and B F Rodrigues

Lakes supply water for irrigation, drinking, fisheries, etc., and thus have significant economic and recreational value. In limnetic ecosystem, water quality is influenced by physical, chemical and biological factors. Freshwater communities are considerably sensitive to environmental variables. The algal flora constitutes a vital link in the food chain and its productivity depends on water quality at a given time. Diatoms, especially are of utmost importance, as they're the potential indicators of water quality thanks to their sensitivity and powerful response to several physical, chemical and biological changes. Occurrence of diatom communities in selected water bodies of Goa along side physico-chemical parameters are studied for a period of two consecutive years and therefore the data has been used in bio-monitoring. Using OMNIDIA GB 5.3 software, Louis Leclercq IDSE/5 index springs and therefore the level of degradation thanks to organic and antropogenic pollution has been acknowledged . Findings showed differences due to the season in physico chemical parameters and diatom population. The decent variety of diatoms was extensively high in Syngenta, Lotus and Curtorim lakes when contrasted with Khandola lake. Gomphonema parabolum, Navicula halophila, Navicula microcephala, Navicula mutica were showing natural contamination in all water bodies. Amphora ovalis, Stauroneis phoenicenteron, Synedra ulna were showing antropogenic contamination at Syngenta, Lotus and Curtorim lakes while Navicula rhynococephala was demonstrating antropogenic contamination at Khandola lake. Biomonitoring has been demonstrated to be fundamental and consequently the significance of diatoms as biological markers of water quality has been focused.

Freshwater people group are a lot of touchy to ecological varieties . Phytoplankton elements impact trophic levels and movability of water for human employments. Monitoring of water quality with regards to physical and chemical parameters reflects instantaneous measurements while, biotic parameters developed during the recent years have served as a superb tool in the area of pollution studies and provides better evaluation of environmental changes [4]. Diatoms are potential indicators of water quality due to their sensitivity and strong response to physico-chemical and biological changes .Juttner et al. studied environmental changes using diatom assemblages, relationship between diatoms and therefore the water chemistry parameters. According to him fluctuation of diatom species to varied environmental changes are often early warning towards freshwater ecological problems. Their sensitivity to small changes in water quality makes them powerful indicators. Several studies on diatoms as bioindicators of pollution are administered earlier. Biological monitoring is a fast and cost-effective approach for assessing the effects of environmental stressors, making it an essential tool . Various indices are developed for monitoring pollution in water bodies. One of the only and effective water quality index, utilizing diatom population is IDSE/5-the index of Saprobity-Eutrophication. This index is obtained from the OMNIDA GB 5.3 software which indicates the standard of water in terms of organic pollution also as anthropogenic eutrophication. The design of OMNIDA Software for computation of diatom indices has facilitated the utilization of diatom based biomonitoring. The software may be a comprehensive data base having an inbuilt ecological data for 13,000 diatom species. Present study discusses diatoms as indicators of water quality of selected water bodies using Louis-Leclercq Diatomic Index of Saprobity-Eutrophication (IDSE/5) and therefore the quality of water in terms of organic pollution as well as anthropogenic eutrophication.

Two water bodies each from North Goa (Syngenta Lake and Khandola Pond) and South Goa (Lotus Lake and Curtorim Lake) were selected for the study from January 2014 to December 2015 on monthly basis. Water samples were collected within the early hours as daily vertical migrations of organisms occur in response to sunlight and nutrient concentrations from the surface near the landward margins. Physicochemical parameters such as pH, temperature, nitrates and phosphates were analysed using standard procedures [15]. For phytoplankton study one litre of water sample was collected in sterile plastic bottles (three replicates were taken) and Lugol’s solution (0.7 mL/100 mL of sample) added immediately for sedimentation. The bottles were subsequently left undisturbed for 24 h. The phytoplankton fixed and settled at the bottom of the containers after decanting the supernatant fluid were collected and preserved in bottles containing 4% formaldehyde. Identification of diatoms was finished by altered Lackey's drop technique. Measurements were estimated utilizing micrometry strategy and photomicrographs were taken utilizing Nikon DS Fi 2 camera. Various taxonomic guides were consulted [17-20]. Each taxon was codedwith acronyms as per the rules of OMNIDA GB 5.3 software. Diatom species counts were entered into diatom database and index calculation tool, OMNIDIA version 5.3. The output of the software provides many metrics of water quality through the indices and ecological characteristics. The Louis Leclercq IDSE/5 index was calculated through this software. Seven biological marker esteems given by Van Dam et al. were determined for chosen water bodies utilizing the OMNIDIA GB 5.3 programming and were utilized for understanding of results. These qualities show the conditions required for development and endurance of diatoms. These incorporate pH, saltiness (H), nitrogen uptake (NU), oxygen requirements (OR), saprobity (SP), trophic state (TS) and dampness (M) and furthermore decide the water quality. Each parameter is measured on a scale of 1-7. OMNIDIA is additionally wont to compute degradation (D) using IDSE/5 Louis Leclercq index for organic pollution (OP) and anthropogenic eutrophication (AE).Syngenta Lake is within the premises of M/s Syngenta Agro Chemicals at Corlim Tiswadi taluka located on the banks of Cumbarjua canal. Khandola pond is situated between 15.50N Latitude 73.90E Longitude of Marcela. It is a source of irrigation to areca nut plantation in surrounding areas. Lotus Lake is situated between 15.20N Latitude and 73.90E Longitude, Lake is polluted and has abundant growth of aquatic weeds. Curtorim lake is Situated between 15.20N Latitude and 74.00E Longitude. All four water bodies differ in dimensions, size, nutrients concentration, nature of aquatic life, usage and level of human disturbance. From the results it is concluded that there deterioration of water quality of the water bodies undertaken for the study.
 

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Biodiversity Congress 2018: Exploration of land-cover changes using GlobeLand30 (2000-2010) at the national level in Mexico

Rafael Moreno-Sanchez, Juan Manuel Torres Rojo, Francisco Moreno Sanchez, Daniel Carver1, Lily Niknami and Elizabeth Clay

This study explored the Land Cover (LC) and LC transitions at national level in Mexico using the GlobeLand30 (GL30) land cover 30 meter resolution data sets for the years 2000 and 2010. This information was contrasted against the results of previous national level Land Cover (LC)/LC Change (LCC) studies and land cover/use digital data sets. consistent with GL30, wetlands and barelands have had the most important decreases in their areas during the 2000-2010 period (-13.33% and -9.26%, respectively), while artificial surface and grasslands have had the most important increases (7.38% and 4.00%, respectively). Cultivated (1.88%), forest (-0.47%), shrublands (-1.04%) and water bodies (-1.21%) show low changes during the 2000-2010 period. From the GL30 estimates of LC extent and percent change, those for the forest and cultivated classes were the foremost almost like those estimates reported in previous studies. The estimates for other LC classes show low agreement with previous studies and with a group of aggregated LC classes created from official digital LC maps. Worth noticing is that the small decreased found for the GL30 Forest land cover class during the 2000-2010 period. this means a change in processes that in previous decades were reducing the extent of the forest cover in Mexico. the overall reduction in LC transitions observed within the 2000-2010 GL30 data supports reports that allocations for a few land covers/uses in Mexico have reached maturity and are tending to stabilize. The results of this study points to many needs for further research, like completing assessments of the locational and classification accuracy of the GL30 data sets for Mexico. More specifically, there's a requirement to closely analyze the extent and changes within the GL30 artificial surface and wetlands LC classes. Wildlife habitat and species round the world face a crisis. it's estimated that heating may cause the extinction of 15–37% of species by 2050. this is often another aspect which needs attention because we could lose about 1.25 million species. Unlike other environmental losses, this one can't be reversed because nature doesn't give second chances to biodiversity.
Wildlife resources constitute an important link within the survival of the human species and are a topic of much fascination, interest, and research everywhere the planet . Today, when wildlife habitats are under severe pressure and an outsized number of species of untamed fauna became endangered, the effective conservation of untamed animals is of great significance. Because all folks depends on plants and animals for all vital components of our welfare, it's quite a matter of convenience that they still exist; it's a matter of life and death. Being living units of the ecosystem, plants and animals contribute to human welfare by providing
  • material benefit to human life;
  • knowledge about genetic resources and their preservation; and
  • significant contributions to the enjoyment of life (e.g., recreation).

Human society depends on genetic resources for virtually all of its food; nearly half its medicines; much of its clothing; in some regions, all of its fuel and building materials; and a part of its mental and spiritual welfare.
Considering the way we are galloping ahead, oblivious of what legacy we decide to leave for future generations, the longer term doesn't seem too bright. Statisticians have projected that by 2020, the human population will have increased by quite half, and therefore the arable fertile land and tropical forests are going to be but half what they're today. Genetic resources are treated as inexhaustible natural resource , but we'd like to worry about them. it's here that the concept of management and conservation of wildlife comes into play, because anything that's not human or undomesticated is ‘wildlife’. Presence or absence of an animal or plant during a region is decided by ecological and historical factors. Animals and plants live indicators of the characteristics of their environment; their ranges mark the places where environmental conditions are an equivalent or similar. To interpret the range of a species properly, it's necessary to understand , in detail, the conditions required for the species to measure and thrive. On this basis, the planet are often divided into six zoogeographical regions:
1) Nearctic North America and Greenland
2) Palaearctic Eurasia, without India
3) Ethiopian Africa, south of the Sahara
4) Oriental India and Indochina
5) Australian Australia and New Zealand
6) Neotropical South and Central America, and therefore the Antilles

The high cost of captive breeding and therefore the paucity of additional release sites threaten gharial conservation efforts. Increasing interactions between riverside human populations and therefore the gharial, also because the negative effects of agriculture and fishing restrict successful gharial populations to a couple of stretches along isolated and guarded rivers. Gharial migration out of protected areas has been identified as a big factor that's slowing population recovery.
If we take into consideration the traditional reasons why wildlife is disappearing in Asia, India is doing much better than other countries. India has launched an in depth protected area network of research institutions during which legislation, socio-economic factors, and wildlife research are playing an excellent role. The Central Zoo Authority plays a key role with zoos in programming research activities associated with the conservation and propagation of untamed animals. Planned research activities include studies on wildlife biology, genetic variability, species- specific nutritional requirements, animal behavior, epidemiological surveys, and disease diagnosis through autopsy. The longer term depends on interaction between captive and wild animals, preservation of biodiversity, and genetic and demographic variations of species. India still has 65% of Asia’s tiger population, 85% of the Asian rhino population, 80% of the Asian elephant population, and 100% of the Asiatic lion population.
 

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Biodiversity Congress 2018: Biodiversity of Manukau mangroves; whatâ??s really in there?

Amrit Melissa Dencer Brown

Introduction: How we perceive and interact with the natural world will govern our future in times of great environmental change. In New Zealand, the indigenous mangrove species Avicennia marina (subsp.) australasica has expanded within estuaries in the North Island at a rapid rate over the past few decades. This has led to polarity in public perceptions and attitudes towards mangrove preservation and removal. Although protected, removal of huge areas of mangroves has occurred and continues to require place. This thesis investigates the social-ecological trade-offs between removing and preserving mangroves in New Zealand. The research approach employs a mixed methods Holistic Mangrove Framework, which explores gaps within the social-ecological monitoring of mangroves both nationwide and specifically at four sites of removal in the Manukau Harbour, Auckland. Chapter two’s review of the literature on mangrove social-ecology showed that prominent knowledge gaps remain in ecological monitoring of mammals, reptiles, insects and spiders, which is also true globally. In a social context, little is known about the cultural value of mangroves (manawa) to Māori or the intrinsic value of this ecosystem. Chapter three showed the creation of a completely unique framework to research the creeping environmental problem of mangrove expansion in New Zealand. This framework has the capacity to be applied to any social-ecological system for a holistic understanding of interactions between humans and nature. Chapter five’s integrated biodiversity assessments revealed that there is much heterogeneity in habitat complexity, species richness and abundance among sites. The study site adjacent to the largest mangrove removal area possesses the greatest abundance of bird species, and richness and abundance of arboreal arthropods compared to all other study sites. This highlights that a siteby- site management approach is required and generalisations about the ii habitat value of mangroves for wildlife cannot be made in the New Zealand context. Chapter six’s exploration into perceptions and attitudes towards mangrove preservation and removal revealed significant disparity in attitude between community groups and conservation organisations. Sediment and nutrient retention properties of mangroves are the highest rated ecosystem services. The desire for reversion of estuaries to a pre-urban state is that the greatest issue affecting mangroves. Iwi recommend monitoring of water quality and contaminants in mangrove soils. Based on the findings of this study, it is recommended to look beyond mangroves as an ecosystem which has expanded and replaced other adjacent habitats and start thinking about managing our coastal landscapes in a holistic manner. Embracing connectivity and complexity of coastal landscapes and addressing wider land-based issues of sedimentation and nutrient run-off is a necessity. It is advisable for us to work with and be part of our natural environment in order to create a more sustainable future in Aotearoa New Zealand. This is true for interactions with social-ecological systems globally. This study has added to baseline data on social and ecological information on New Zealand’s mangroves and contributes to the international body of work on this coastal ecosystem using a mixed methods approach.

Aim: to research what biodiversity of species exists at fragmented mangrove sites in Auckland.

Research objectives of the study are as follows:
1. To review the literature on social and ecological studies in New Zealand mangroves in order to identify gaps in social-ecological information regarding mangroves
2. To create a mixed methods framework based on social-ecological systems in order to address the overall research aim
3. To investigate secondary social-ecological data from council resource consents to compile background knowledge on a) the ecological assessments and b) the demographics and opinions towards specific removals of community stakeholders at selected sites
4. To understand the perceptions and attitudes towards mangrove removal and preservation through interviewing local community stakeholders
5. To conduct integrated biodiversity assessments at the selected sites to provide baseline data for lesser known species occupying mangrove habitats
6. To evaluate trade-offs in order to recommend future courses of action with mangrove removal/management in New Zealand

Methods: a variety of various non-invasive techniques were employed to record presence/absence data of reptiles, mammals, fish and birds utilizing mangroves. Insects and spiders were captured and preserved for identification and future research.

Results: All groups of organisms were found with the exception of reptiles; skink was observed at the marsh-mangrove edges. The most fragmented patch of mangrove had the foremost species in terms of insects and spiders and bird species. The threatened bird the Banded Rail was present at 50% of the sites. There were significant differences between the sites potentially driven by the proximity and connectivity to nearby forested habitats.

Conclusion: Sites differ in terms of biodiversity then each site must be monitored long-term before any removal. The highly fragmented site should be preserved and guarded thanks to its healthy and high ecological functioning, including habitat for shortfinned eels and juvenile yellow-eyed mullet. The results of those assessments have the potential to be implemented in policy for mangrove biodiversity monitoring which can be applied across New Zealand and to mangroves internationally.
 

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Biodiversity Congress 2018: Assessing changes of habitat quality for shorebirds in stopover site: A case study in Yellow River Delta, China

Xiaowei Li

The population of shorebirds within the East Asian-Australasian Flyway (EAAF) is on a severe, long-term decline. One of the explanations is low survival during stopover sites in Yellow Sea Ecoregion thanks to habitat degradation. In this paper, we focused on the shorebird habitat quality in Huang He Delta (YRD), which may be a representative shorebirds stopover site within the Yellow Sea Ecoregion on EAAF. The East Asian–Australasian Flyway (EAAF) has the highest shorebird populations among the world’s flyways (International Wader Study Group 2003; Milton 2003). The population of migratory shorebirds in EAAF has severely declined over the past several decades (Amano et al. 2010). Migratory shorebird populations in this flyway have declined up to 48% (International Wader Study Group 2003), along with perpetual annual declines of as much as 8% for some shorebirds (Studds et al. 2017). The tidal mudflats of the Yellow Sea Ecoregion (YSE) have been a crucial migratory bottleneck for the millions of shorebirds that migrate through this flyway (Barter 2002; Studds et al. 2017). The YSE has lost 28% tidal flat area at a mean rate of −1.2% yr.−1 over the past three decades for land reclamation, leading to growing concerns that habitat degradation at stopover sites may be driving the declines in shorebird populations (Murray et al.2014). Previous studies implied that population declines are driven by low survival during or after staging in the YSE tidal mudflats because birds are unable to replenish their energies to meet the demands of migration (Amano et al. 2010; Studds et al. 2017). Considering that shorebirds rely on stopover sites along their migratory path, they are vulnerable to various threats in these habitats (Piersma and Lindström 2004). Such threats include habitat losses and degradation due to agriculture, mariculture, and industrial developments (Newton 2004; Burton et al. 2006; Yasué and Dearden 2006). To ensure the persistence of migratory shorebird populations, a balance needs to be achieved between conservation and human development requirements. However, achieving such a balance with inadequate information about the consequences of land use (LU) change is difficult. Thus, understanding and predicting the effects of these threats on shorebird habitat quality are valuable for making an initial assessment of conservation needs on shorebird flyways and for projecting changes across time. On this basis, models have been designed to help planners in determining LU configuration to ensure that the biodiversity value of each area can be maximized. Several models, such as the Global Biodiversity (GLOBIO) (Alkemade et al. 2009) and Integrated Valuation of Ecosystem Services and Tradeoffs (InVEST) models, have predicted habitat status and biodiversity as a function of anthropogenic threats (Sharp et al. 2016). GLOBIO is a modeling framework that is used to calculate the past, present, and future impacts of environmental drivers on biodiversity on the global to national scale (Alkemade et al. 2009). The habitat quality module of InVEST (Kareiva et al. 2011; Sharp et al. 2016) has successfully been applied to assess the relative extent and degradation of different habitat types. Considering the hypothesis that areas with high habitat quality support high richness of native species, the InVEST model combines LU/land cover (LU/LC) changes and threats to biodiversity to produce habitat quality maps. In this study, we used the InVEST model rather than the GLOBIO model on the regional scale. In this study, we focused on the Yellow River Delta (YRD), which is a representative and ecologically important shorebird stopover site in the YSE on the EAAF. We used the InVEST model to assess the shorebird habitat quality change in the YRD by considering the consequences of anthropogenic threats. The entire duration of the study was 1999–2016, and the modeling was done on year 2000 and year 2015 data.We also applied the model under future scenario based on government policy planning. The results would help decision makers avoid inefficiencies in LU management. North China Plain, and drains into the Bohai Sea. Approximately 1.26 × 108 t of silt were carried by the river and deposited at the river mouth to form new marshes each year during 2000–2015. YRD has a warm temperate continental monsoon climate with distinctive seasons and rainy summers (Cui et al. 2009; He et al. 2009; Cui et al. 2011). YRD is known for its rich biodiversity (phytoplankton, vascular plants, invertebrates, fishes, birds, etc.) supported by various habitats and has become an important overwintering stopover and breeding site for migrating birds in EAAF. This site used to support >100,000 shorebirds during northward migration and an estimated >70,000 during southward migration (Barter 2002). We adapt the habitat quality model of the InVEST for the assessment of shorebirds habitat quality change in YRD during 2000-2015 and future, considering the effects of anthropogenic threats on shorebirds habitat. In our results, the abundance of 11 species of shorebirds had significant downward trends (70-97% reduction) during 1999-2015. The most prominent land use changes within the YRD during 2000-2015 are the shrinkage of estuarine delta and dense-grass, along side the expansion of city, saltern and mariculture. The area of estuarine delta, unused land, tidal flats and sparse grass reduced 30214, 21792, 6510, 6166 ha, respectively during the 15 years. There was high spatial heterogeneity in modeled habitat quality within the YRD. Tidal flats areas within the nature reserve (part 2) had higher habitat quality than areas within the northwestern (part 1) and eastern (part 4) parts of the study area, where the major mariculture occurs. Mean habitat quality within the part 1and part 4 was 26% and 44% less than mean habitat quality partially 2, respectively. The mean habitat quality partially 1 and part 4 decreased 27% and 31% during 2000-2015, respectively. Optimal habitat in YRD declined from 1433 km2 in 2000 to 1154 km2 in 2015. The habitat quality shows a big downward trend within the southeast and northeast of YRD during 2015-2020. The results would help decision makers avoid inefficiencies in land use management.

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Biodiversity Congress 2018: Metabarcoding and culturing to investigate the diverse fungi associated with cabbage in and their bio-control potential

Michal Kuchár

Statement of the Problem: Agricultural crops like cabbage (Brassica oleracea var. capitata) are vulnerable to a plethora of pests and diseases. Endophytic fungi are increasingly used in biological control against these pests and diseases as agricultural producers plan to reduce their environmental footprint.

Methodology & Theoretical Orientation:
During this study, putative endophytic fungi were isolated from cabbage grown in three regions in New Zealand so as to spot isolates with potential to help crop production. Isolation method was optimised in an exploratory study, and subsequently large scale sampling took place, where a culture-independent method was also used to detect fungi associated with cabbage. Spatial patterns in fungal communities in various plant tissues and geographical regions were investigated based on data obtained by culture-dependent and culture-independent methods. Selected fungal isolates were tested in bioassays to work out their potential for biological control of a fungal disease caused by Sclerotinia sclerotiorum and an insect pest of cabbage - Diamondback moth (Plutella xylostella). In addition to isolation from plants, patterns in fungal communities were also described using metabarcoding data acquired by high-throughput sequencing and compared with data on direct isolation through culturing.

Findings: Over 100 species were identified using culturing approaches, while metabarcoding approaches suggest the amount of fungal species related to cabbage tissues might be over 200. Fungal communities differ in above and belowground parts of cabbage. There does not seem to be a significant difference between fungal communities in different regions of New Zealand. Fewer species were recovered in both years than would be expected, nevertheless, these taxa stand out as ubiquitous and abundant; fungi such as Alternaria, Boeremia, Cladosporium, Fusarium, Monographella, Plectosphaerella, Pyrenochaeta and Stemphylium were isolated in most of the sampled plants and usually in high frequencies. However, most of the species isolated in this study were rare. Such distribution of fungi is similar to that in a study describing mycorrhizal and phylosphere fungal communities [139], or to the one describing potential of endophytic fungi isolated from oilseed rape [153]. It is not possible to directly compare 2015 and 2016 studies, given differences in plant ages, isolation approaches, and sampled fields. Nonetheless, the relatively large number of species found in only one year or the other is consistent with a very high total diversity of fungi in these systems. Increased mortality of Diamondback moth larvae feeding on cabbage leaves treated with spore suspensions of several isolates of Lecanicillium sp. was observed. None of the tested isolates used as seed inoculants significantly reduced disease symptoms caused by Sclerotinia sclerotiorum during a bioassay on cabbage seedlings.

Conclusion & Significance: During this study several isolates were identified as promising biological control agents of an insect pest of cabbage. However, these isolates are members of a large consortium of fungi. The uncovered patterns within the fungal communities underline the importance of understanding of the microbial communities related to agricultural crop for us to enhance it. Endophytic fungi isolated from internal tissues of crop plants such as cabbage, have potential for improving crop production through biological control of pests. Diverse fungal communities can be detected, not only by isolation, but also culture independent methods such as Illumina high-throughput sequencing. This study is far from being exhaustive in describing microbial communities associated with cabbage but gives a solid description of fungi associated with different plant tissues across different geographical regions. Three out of over fifty isolates tested, showed potential for biological control of Diamondback moth, however, further research needs to be conducted in order to formulate a biopesticide based on these isolates, In addition, more pests could be targeted by fungi isolated in this study.
 

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