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Category: Ecology

Seagrasses biomass-density relationship and ecological indicator

Seagrasses are marine flowering plant that comprises more than 60 different species. It grows by rhizome extension forming like grassland. Seagrasses also photosynthesize in submerged photic zone that mostly occur in shallow coastal water. In productive ecosystem seagrasses beds are diverse that can accommodate hundreds of associated species like fishes, macroalgae, mollusks and nematodes. However, biomass-density relationship becomes the center of research that describes the health of seagrass meadows.  Concurrently, biomass-density upper boundaries determined the maximum efficiency of space occupation. In which each distance reflects effective competence in packing biomass which proved as reliable ecological indicators.

 

Biomass-Density of Seagrasses

The researchers gathered 32 studies on 10 seagrasses species distributed worldwide reveals that seagrasses are limited by boundary line. Upon using the applied metric system on this particular research each stand of seagrass distance are perpendicular to the boundary.  However, seagrasses shows poor occupier of space compared to terrestrial plants and algae wherein less volume exploited per unit stand surface. Due to some reasons such as short shoot heights, wasted volume due to internodes length larger than shoot widths.

 

Seagrass comprises different species which shows diverse efficiency in space occupation. However, it occupies different bands of biomass-shoot density signifying conditional differentiation of co-occurring seagrass species. Furthermore, high shoot density dominates in favorable environments compare to harsh environment. As a result, this space occupation revealed as a good tool in understanding aspects of seagrasses ecology. Therefore, it serves as the basis to review fundamental aspects including clonal growth pattern, seasonality, competition and depth distribution.

 

Biomass-density of seagrass meadows is limited by interspecific boundary line making a maximum efficiency of space occupation. Though, species tends to differentiate the bands each scatter plot showing conditional differentiation. Moreover, during summer it shows the most favorable season and lower intertidal in correspond to depth. Therefore, the competence of space occupation requires biomass and shoots density of stands measured by vertical distance to the seagrasses.

 

Source: Prepared by Joan Tura from BMC Ecology

Volume 18: 24, October 19, 2018

Black-legged Kittiwakes: Sperm collection, characterization and morphology

Blacked-legged Kittiwakes are pelagic gulls that often feed on fish and macro-zooplankton at the ocean surface. They breed in colonies ranging from few to thousands of pairs which prominently observed in their open, sea-cliff nesting habitats. Blacked-legged Kittiwakes are the most popular models for research because they can be easily monitored and captured. They also considered as prime indicators of fluctuating conditions in marine ecosystem. The purpose of this research is to collect live sperm of blacked-legged Kittiwakes using a non-invasive method. Also, be able to provide information on suitable extenders and timing in relations to the breeding phenology. Additionally, it will offer informations to different disciplines including veterinary science, conservation biology, ecotoxicology and evolutionary biology.

 

Sperm collection of Blacked-legged Kittiwakes

Sperm of blacked-legged Kittiwakes were obtained by firmly massaging the lower back and the tail base of the male bird. Since, the researchers observed that during mating the male tend to wag their tails thus, releasing the sperm naturally. After massaging the handler lift the tail, clear the feathers around cloaca and gently squeeze the cloacal area. While doing this a capillary tube placed on the top of the cloaca to collect directly the translucent liquid. Then, verified directly to the laboratory under the microscope.

 

The result demonstrates a successful collection of live sperm under field condition of blacked-legged Kittiwakes for the first time. In which the researchers discovered two extenders suitable for maintaining the sperm however, undiluted sperm also performed well in terms of survival. Since, seminal fluids alone are sufficient enough to maintain the sperm alive. Though, the researchers still recommend using sperm extenders since it is necessary to dilute highly concentrated ejaculates. Also, extenders are necessary on sperm quality examination when comparing experimental groups and sperm production.

 

Blacked-legged Kittiwakes are strictly monogamous and stores semen inside their body unlike passerine birds that stores semen in seminal glomera. Interestingly, one has to keep in mind that sperm quality may vary seasonally. So, the researchers suggest that one should statistically account for this effects using date relative to laying eggs. Also the researchers recommends to target specific time window when the birds are about to copulate but not after copulation within a day.

 

Source: Prepared by Joan Tura from BMC Avian Research

Volume 9:24, 14 July 2018

Reproductive Success of Medicago sativa: Pollen and Resource limitation

Medicago sativa is a perennial flowering plants that belongs to a legume family.  This plant is known in forage crop, grazing, silage, green manure and cover crop.  Medicago sativa develops potential for medicinal uses and thrive mostly in an arid climate. The aim of this particular research is to determine the floral traits and pollinators visitation activities that affect pollen limitations. It also identifies possible effects of resource allocation on pollen supplementation and the impacts of pollen on flower opening.

 

Medicago sativa floral traits and pollinators

Plant reproduction is limited due to pollen resources, floral traits and pollinator activities. Medicago sativa was observed at about 120 hours by collecting pollens and nectars. The pollinator type was then noted. It was then recorded the visitation frequency and behavior of flowers based on insects as effective pollinators or occasional pollinators. The pollinators then, captured using insect nets to find out the presence of pollen grains.

 

The result shows a positive relationship between pollinators visitation frequency and the number of open flowers. It also found out that, it is more efficient for pollinators to visits opening flowers. Since, filaments of Medicago sativa will dry easily particularly in an arid regions. Moreover, flowers of Medicago sativa was completely open and the pollen released between 09:00 to 14:00 hours. Additionally, some insects identified as effective pollinators because it can collect more pollen and visit more often. However, a reduction of pollinators will decline the amount of pollens and reduced the probability of cross pollen transfer.

 

Overall, this research found out that pollen resources is the limiting factor for the reproductive success of Medicago sativa. It also shows that resource reallocation can increase pollen limitation and plants might reallocate among flowers. However, insufficient pollen deposition is typically caused by pollinators assemblage, visitation and abundance.  In which flowers is the main effects of resource limitations and pollinators plays an important role in outcrossing.

 

Source: Prepared by Joan Tura from BMC Ecology

Volume 18:28 August 29, 2018

 

 

 

 

 

 

 

 

 

 

Longest recorded trans-Pacific migration of a whale shark

Whale shark is a slow moving carpet shark and known as the largest extant fish species. It has a very huge mouth yet it feeds almost exclusively on plankton and small fishes. In marine biodiversity records whale shark showed the longest migratory path. Migratory behavior of marine species has been subject for research studies since it is important for optimizing growth and foraging opportunities. It also caters the breeding ground at discrete geographical locations and identification of different habitats across several jurisdictions. Also, it serves as the key for spatial planning and international policy management for ecosystem resources. Furthermore, gene flow, connectivity and population status are essentials for the marine conservation especially for migratory species.

 

Whale shark Migratory Route

On September 16, 2011 three female whale shark were tag using satellite transmitter model SPOT 253C. The tag specifies battery life wherein transmission occurs only when the animal is swimming near surface to maximize battery life. One female whale shark named Anne remained in Panamanian waters for 116 days then to eastern Pacific for 226 days. Then transmission began again at Hawaii after 235 days of silence then continued to Marshall Islands for about 268 days. But then transmission were interrupted again when the Anne reach the Mariana Trench.

 

So, the whale shark Anne travelled a long distance of 20,142 km approximately from Panama to Mariana Trench. Throughout this period Anne spent the entire time above thermocline with a temperature ranging from 15.1–35 °C. The route taken by Anne followed primarily westward North Equatorial Current similar to other whale that has been tracked previously. These results show that long periods without transmission do not necessarily entails tag shedding. Thus, this unusual long distance travelled of Anne and the intervals between detection offers evidence both tracking and genetic studies. It also suggests that whale shark is capable of long-distance travel.

 

Whale shark can migrate from Eastern Pacific to Western Indo-Pacific connecting two ocean basin using North Equatorial Current. It also imply that a potential passageway to reach Philippine Sea into South China Sea to get to Indian Ocean. Moreover, the results of this record are consistent to the genetic studies showing potential dispersal of whale shark. Overall, these two tracks showed by Anne expose the complexity of management of endangered species crossing multiple jurisdictions. Yet, the protection and conservation programs focused only at the local level rather than across Pacific.

 

Source: Prepared by Joan Tura from BMC Marine Biodiversity Records

Volume 11:8, April 19, 2018

Ecosystem carbon emissions from forest fires in Alaska

Carbon emissions in Alaska relied on measurements of trees and changes in surface organic layer carbon pools after large-scale burning. In 2015 hundreds of forest fires burned across the state of Alaska resulted as second highest acreage burned in a year.  Nearly 300 forest fires occur in a week, as a result over 61,000 lightning strikes detected during this period. As of mid-September a total of 2.1 million hectares has been burned statewide in 700 separate forest fires. Deeper burning of surface layers happened during fires and on more well-drained sites at moderate to high severity levels. Summer of 2015 in Alaska has an exceptionally warm and dry condition following the largest forest fires recorded in decade.

 

Forest fires estimated carbon emission

Estimated burned depth from forest fires consumed almost the surface organic moss layers at about 5cm-10cm depth. This estimate confirmed using the relationship of every centimeter of organic mat thickness and soil temperature under organic layer. In sternly burned forest a total consumption of living moss organic layer is directly associated with warming at the soil surface layer. Additionally, soil temperature at about 30cm depth has 8–10 °C higher compared to unburned forest sites. Therefore, forest fire impacts on forested areas caused a fivefold decrease in surface organic layer thickness. As well as doubling of water storage in the soil layer, doubling in thaw depth and increase soil temperature.

 

Moreover, carbon emissions include the measurement above ground biomass and changes in surface organic layer carbon pools. In 2017 field surveys of Tanana, Alaska shows no live surface organic layers remained from 2015 forest fires. Due to these intense fires only residual dead, charred moss and lichen left behind that could not insulate soil layers. Also, post-fire thickness of organic layer and thermal conductivity are important factors to determine soil temperature and thaw depth. Nevertheless, the role of mineral to the total ecosystem carbon emissions is higher in forests that are normally calculated.

 

Forest fires have overall percentage of more than 60% in interior Alaska. And this abrupt removal of moss and soil organic layer elevates post-fire soil temperatures and thaw depths. Because of this a massive loss of carbon and nitrogen from soil layer minerals. As well as, a much warmer and wetter surface layer compared to unburned forest nearby. Therefore, carbon emissions are due to the addition of mass wasting of soil mineral in 2 years following forest fires.

 

Source: Prepared by Joan Tura from  BMC Carbon Balance and Management

Volume 13:2 January 8, 2018

Impacts of millennium drought on butterfly faunal dynamics

Butterflies are flying colored wing insects that vary in color and pattern from individual to another individual. It has wings covered with overlapping rows of scales. Most of butterflies have developed mechanisms to   avoid predators making disguise coloration blending like leaf or bark of the tree. Some releases chemicals as a defense mechanism wherein butterfly evolved to have toxic chemicals. But recent finding due to extreme weather events and trend linked to ongoing anthropogenic climate change species shifts its dynamics. Droughts occur more often in larger spatial scale which has an effect on insects. Generally, drier and warmer climatic conditions have an impact either positive or negative to insect populations. The aim of this research is to address the knowledge gap using multi-decadal dataset of 163 butterfly species. All of this butterflies experienced millennium-scale drought.

 

Impacts of droughts on Butterflies

To know the faunal dynamics, investigation of phenology, species richness and diversity with its elevation gradient has been conducted. In which linear model used to understand differential sensitivity of butterflies to climate change at low and high elevation. A decade of dataset of 163 butterfly species across elevational gradient in Northern California has been considered. Results showed that a prolonged shift towards spring flight during drought years and change in phenology is evident across elevations. It also happened that the total flight window expanded at lower elevations while at higher elevation shifted and compressed. This leads the notion that fewer overall flight days at higher sites.

 

The millennium drought in California created across site with elevation-specific changes in flight windows and species richness. This resiliency reveals that lowest elevations are less detrimental than biotic-abiotic association at higher elevations. Most of the researchers hypothesized a mismatch between trophic levels as a result of climate change. But, results of butterflies from low elevation would suggest that at consumer trophic level need not always have negative impacts. Additionally, species at lowest elevations have access to agricultural lands though irrigation does not correlate the population dynamics during drought. Thus, there is a possibility that low elevation population buffered by irrigated crops or agricultural margin during drought.

 

Indeed, that at high elevation butterflies declined in number and become sensitive to dry years with warmer temperatures. Contrary to the theory that mountains offer microclimatic refugia and adapt species for climatic changes. It has been known that high latitude environments are warming faster with negative consequences to several species. But positive or have a neutral effect for other species. Consequently, this research suggests more thorough investigation about organismal responses to extreme weather. As well as on the extent wherein different habitat type may or may not buffer species populations against climate change.

 

Source: Prepared by Joan Tura from Springer BMC Climate Changes Responses

Volume 5:3 26 January 2018

Tracking the migration of Whip-poor-will in Americas

Eastern whip-poor-will (Antrostomus vociferous) is continuously declining due to habitat loss and unavailability of insects for food. Little is known about whip-poor-will migration because of their nocturnal quite habit during non-breeding season. At high latitude 80% avian species are migratory wherein factors affecting migration includes predators, anthropogenic threats and pathogens. Migratory strategies allows individual to track seasonal changes mostly for temperate breeding aerial insectivores. However, population declines among temperate insectivore birds due to extreme weather condition, cost of migration and reliance on sensitive prey. In addition it is important to determine the migratory routes, year round habitat requirement and temporal constraints of threatened species.

 

Geolocator deployment of Whip-poor will

There were 20 males and 2 females of whip-poor-will have been tracked using geolocators in four regions of Canada. The study shows that this species breed more in northern part than southern breeding population and experienced different wintering conditions. Also a high migratory cost happens such as novel threats, energy expenditure and the ability to adjust time in tracking breeding ground condition.  In contrast, both eastern and western breeding individuals wintered together wherein mostly concentrated in Guatemala and some provinces of Mexico. However, male often have higher benefits of early arrival on the breeding grounds thus accept higher cost of wintering further. Additionally, early arrival on breeding grounds is more advantageous on whip-poor-will males allowing occupation on higher quality territories.

 

On the other hand female whip-poor-will forced to migrate further on lower latitude with less competition and more abundant resources. Most of this species travel overland through Mexico and Central America. However, only two individuals flights across portion of the Gulf of Mexico during autumn and spring. It just shows that this pattern is the response to prevailing winds and availability of resources along different route. Also more species migrating along Eastern North America, South and Central America over ocean flights during autumn. While in spring more species taking longer over land route around western side of the Gulf of Mexico.

 

Therefore, geolocators is helpful in identifying wintering areas, stopovers and migratory route of whip-poor-will. These migratory stopovers in the southeastern and central United States as well as in southern Mexico and Central America are both important for the whip-poor-will species. Finally, habitat protection and insect population might increase the number of these species despite pressures of long migrations and climate changes.

 

Source: Prepared by Joan Tura from Springer BMC Zoology

Volume 2:5, 2017

Endangered ecosystems: Review on conservation status of Asian rivers

Physical, chemical or biological changes in the environment that will affect its equilibrium are indeed a need of thorough investigations. For it will create a compounded effect from the lower living organisms up to a higher one. This particular article cited the conservation strategies that sustain life on tropical Asian rivers way back two decades ago. River ecology is dominated by flow seasonality imposed by monsoonal rains with profound consequences for fishes and zoobenthos. Riverine biodiversity is threatened by habitat degradation, pollution, flow regulation, river regulation and control as well as over-harvesting. It is emphasized on this article the factors affecting ecological niche of the river based on the survey. At different level from biotic and abiotic features which is very important in determining the flora and fauna.

 

Threats to tropical Asian Rivers

Water elements and hydrochemistry in relation to its topography and latitude will constitute the wide range factor in ecological balance. Floodplain ecology is economically importance for the breeding and feeding sites of fishes and other aquatic organisms. Between the riparian forests indicates the lateral-interactions for carbon processing as well as trophic production. Two decades ago technologies are not yet fully develop compared today yet problems of river system existed way back time. Seasonal change in Asia will also affect the amount of water in the river catchment.

 

Mekong River is significantly important for potential energy that is why United Nation makes a committee to investigate. Irrigations, dams have been established all along the Mekong River to control the floods. Yet it cause an environmental impact and environmental consequences which affects balance patterns of nature and its species itself. Like for example the change in inundation patterns that affects productivity. Changes in flow and temperature may remove important directive factors for breeding and migratory behavior of some species.

 

Proper policy implementation and regulation in River system are very important it must foresee wide range effect to the environment. One single action will affect the whole system of the environment. Though this is still open for argument nowadays since politics and businesses will always contradict for maintaining the pristine ecosystem. Adequate management and efforts in assessing environmental impacts and collaborative studies is indeed necessary. Also a manifestation and proper policy for a good river ecosystem management are deemed needed. This is the challenge and continuing advocacy to limnologists to visualize and assess the sustainability and conservation of river ecosystem.

 

Source: Prepared by Joan Tura from Springer Hydrobiologia 

Volume 248, Issue 3 pp 167–191

First record: Common bottlenose dolphin in Canadian Pacific waters

Common bottlenose dolphins are the largest species of the beaked dolphins that inhabits in temperate and tropical oceans worldwide. These species are large that mostly found in groups and known to mixed with other species like whales and cetaceans. Common bottlenose dolphin diet mainly squid, eel, shrimp and wide variety of fishes by swallowing a whole than chewing it. Dolphins usually search prey using echolocation in a form of sonar. And uses sounds for communication like squeaks emitted from blowhole, whistles from nasal sacs and body language. The coastal of United States Pacific is known to have around 450 individuals while the offshore population about 3,495 individuals. In Canadian west coast no common bottlenose dolphin has been documented. However, on July 29, 2017 a sighting of this species mixed with cetaceans and killer whales has been observed.

 

Common bottlenose dolphins observed in Canadian waters

For the first time common bottlenose dolphins have been observed on July 29, 2017 in Canadian water. Each individual shows particular characteristics like short to moderate beak. A curved mouth line that dips downward resembling like a smile and tall falcate dorsal fin at the central back. Moreover, the body colors were usually light grey to black on the back and side while light to white color around the belly.

 

The sighting of the large group of common bottlenose dolphins is the first confirmed occurrence in Canadian Pacific waters. The location of sighting is approximately 1000 km northwest coast of America which signifies the first northernmost record of the species. About 200 dolphins were seen in the group in an unusual large aggregation. On the other hand it was also observed that this dolphins traveling closely with false killer whales, a typically offshore species.

 

The discovery of common bottlenose dolphins and false killer whales signifies the warming trends in North Pacific waters. Both of the species typically inhabit warm temperate waters in lower latitudes. But this sighting indicates that British Columbia, Canada oceanic conditions gives suitable habitat for them. It is also recorded that the show-up happened after a prolonged warming period.

 

Source: Prepared by Joan Tura from  Springer Nature BMC Marine Biodiversity

Vol. 11: 3, 20 April 2018

Population trends, threats, and conservation of Waterbirds in China

Waterbirds are very important indicators in the ecosystem particularly wetlands. Due to climate change and human activities such as pollution, over-hunting and habitat loss about 23% globally are declining. Some have been listed as threatened species by the International Union for Conservation of Nature (IUCN) for about 19% worldwide. In view of this severe condition, waterbirds diversity has been rapidly decreasing and its conservation status received attention. In China there are 53.6 million hectares of wetlands making it the first among Asia and fourth in the world. There were different wetland types in China including swamps, rivers, lakes, coastal wetlands and estuaries. Conservation of waterbirds in China has been implemented establishing nature reserves, designating key habitat and captive breeding to increase population.

 

Population Trends of Waterbirds in China

According to Wetlands International there were 871 waterbird species in 32 families and 8 orders in the world. In China, 260 waterbird species has been identified that belongs to 21 families. 84 species exhibited a declining trend, 35 species remained stable while 16 species showed increasing trends. Threatened species includes Critically Endangered, Endangered, Vulnerable, Near Threatened, Least Concern and Data Deficient.  Moreover, the migratory and residents waterbirds suffered serious threats and a total of 38 species listed as threatened species. Also there were 6 species listed as Critically Endangered, 16 species Vulnerable, 16 species Endangered and 27 species as Near Threatened.

 

Threats to waterbirds include both direct and indirect human activities such as illegal hunting, disturbances, pollution and habitat loss. However, habitat loss is the most common threat because of large scale reclamation in both coastal and inland wetlands. According to the national surveys a decreased of 3.4 million hectares of wetlands wherein coastal losses more than inland wetlands. In recent years, continuous development and industrialization affects the natural habitats of waterbirds. In which foraging time have been reduced, vigilance behavior increased and recurrently being flushed away. As a consequence human disturbances forced the birds to abandon habitats and nest due to breeding failure.

 

Therefore, waterbirds in China might be in more serious situation than we thought that is why conservation must be implemented. Like restoration of degraded wetlands, public awareness, cracking down on illegal hunting and enforcement of Wildlife Protection Law. Additionally, restoration of highly threatened species through artificial intervention is needed. As well as promoting cooperation between international and regional information on conservation.

 

Source: Prepared by Joan Tura from Springer Nature BMC Avian Research

Published: 28 April 2018