Categories
Ecosystem Dynamics Environment

Agroecosystem and the Rise of Agroecology

Due to the lack of exhaustive reference material on agroecosystem for my ecosystems dynamics class, I decided to write this post. I defined agroecosystem, characterized it, and introduced agroecology as a sustainable way of producing food. Agroecology is crucial in meeting the ever-increasing demand for the nourishment of almost 8 billion people in the world.

Definition of Agroecosystem

According to Gliessman (2014), agroecosystem is a created ecosystem. It is an ecosystem that is altered and manipulated to establish that piece of land for agricultural production. At the core of an agroecosystem is agriculture. An agroecosystem is not restricted to the immediate site of the agricultural activity (e.g., farm), but rather, the region that is impacted by this activity, usually by changes to the complexity of species assemblages and energy flow as well as to the nutrient balance.

Traditionally, an agroecosystem, notably one managed intensively, is characterized as having a simpler species composition. These ecosystems have simpler energy and nutrient flows than the natural ecosystem. Likewise, agroecosystems are often associated with high nutrient input. Much of the nutrients exit through farm loading to eutrophication of connected ecosystems not directly engaged in agriculture. Some major organizations are handling the agroecosystem. Current farming methods have resulted in overstretched water resources, high levels of erosion, and reduced soil fertility (Audiopedia, 2016).

agroecosystem
Fig. 1. Farmland in Quezon, Palawan, exemplifies an agroecosystem.

Agroecosystem Characteristics

Human management alters a natural ecosystem’s structures and functions. Thus, agroecosystems usually are more challenging to study than natural ecosystems. Agroecosystems are human-made ecosystems that differ from natural ecosystems in many significant ways in terms of emergent properties related to its structure and function.

Table 1 compares natural ecosystems and agroecosystems using some key emergent qualities of natural ecosystems and the changes once converted to agroecosystems.

Table 1: Comparison of Natural Ecosystem and Agroecosystem in Terms of Emergent Properties (Gliessman, 2014; InTeGrate, 2018).

The Rise of Agroecology

Agroecology applies ecological concepts and principles in the design and management of sustainable agroecosystems. It draws on both natural ecosystems and traditional (local or indigenous) agroecosystem. It is a research approach that can be applied to converting unsustainable and conventional agroecosystems to sustainable ones. Both traditional and natural ecosystems have passed the test of time in terms of their long-term productive ability. However, each offers a different knowledge base from which to understand this ability.

There are many examples of traditional agroecosystems that demonstrate how culture and its local environment have co-evolved over time. These ecosystems strike a balance on the needs of people which are expressed as ecological, technological, and socio-economic factors.

Both systems demonstrate people’s concerns about the long-term sustainability of the system, rather than solely maximizing output and profit.

Sustaining Food Production through Well-Managed Agroecosystems

Responsible farming for food production promotes adherence to the sustainability principle. Sustainable agriculture, evidenced by the practice of Agroecology to provide the food needs of a growing population, appears to be a feasible solution.

However, there is an increasing realization among modern societies that production should focus not on just the volume of food produced but the kind or quality of food produced. Food preference shift from meat-based to a mainly vegetable or plant-based diet is recommended to achieve food sustainability.

The trend is a result of the negative externalities brought about by profit-oriented modern agriculture. Eutrophication, water pollution, and concerns about human health ensue.

References

Audiopedia (2016). What is agroecosystem? [youtube]. Retrieved on 10/28/2019 from https://www.youtube.com/watch?v=XYw5nEmQ6Tc.

Gliessman, S. R. (2014). Agroecology: the ecology of sustainable food systems. CRC press.

InTeGrate (2018). Natural ecosystem and agroecosystem comparison. Retrieved on 10/28/2019 from https://tinyurl.com/y4v5wmbc.

Categories
Ecosystem Dynamics Environment

Human-Beings and Ecosystem Interaction: The Complex Adaptive System

Without ecosystem services provided by the environment, human-beings cannot survive nor exist. Human-environment interaction is common to us. It is the usual scene every time we, humans, wake up in the morning and continue the routine of living.

For a moment, can you describe the details if you will be asked, what are the interactions between an individual and his environment? By posing for a while and observing what is really happening, I have found that the relations between human-beings and environment are complex.

In this article, we will see the reality of complex relations between ecosystem and human-beings within one of the remote communities in the island of Palawan that we have visited.

Human-environment interaction are complex adaptive systems. It is complex because ecosystem and social system have many parts that are interconnected and interdependent with each other. Adaptive since it has feedback structures that promote survival in a continuously changing environment.

Humans are highly dependent on the environment. Ecosystem services such as food, water, clothing, shelter, timber and many other resources are essential for human-beings survival. By using these resources, people affect the environment in a lot of ways. Humans modify the existing ecosystem for their purposes and benefits as well as develop new strategies that seem to be more effective in serving their needs.

The type of society strongly affects the attitude and behavior of people towards nature, and therefore brings impacts on ecosystem. Some of the significant characteristics include population size, social organization, knowledge, culture, belief and many more. Values, knowledge and cultures strongly influence peoples’ “view and principles of life” and subsequently define the way people act. The choice of possible actions is then limited by the available resources and technologies.

The Pala’wans – Environment Interaction

The Pala’wan tribe who have settled in the southern part of Palawan island have simple way of living. They are highly dependent on the availability of natural resources within their areas. The practice of traditional agriculture like slash-and-burn farming is one of their ways to produce staple food such as rice, cassava and other endemic crops. They also know unique strategies in fishing and hunting of several wild animals. For thousands of years, their lives are linked with the environment. Their rich traditional knowledge reflects and embodies a cultural and spiritual relationship with the land, river and wildlife.

The selected photo below shows how Pala’wans are connected with the environment. It was taken in May 2013 when my dad and I, together with my group mates in research study in college, visited Sitio Bayabas, Barangay Bunog, Rizal, Palawan. The site is located within Mt. Mantalingahan, one of the protected areas in the province of Palawan.

The site is considered as one of the sacred places of the Pala’wans. Thus, only limited people are allowed to visit the area. And we are fortunate to have that opportunity! Once more, I’m so blessed to witness these great creations of the Lord.

falls
©2013 Shellemai Roa

The Aesthetic Value of the Site

The aesthetic view of the place is like a paradise. You are free to hear the natural sound of murmuring water from a waterfall that continuously flows and rushes within the blocks of big rocks; it has crystal clear running waters with bluish and greenish color in some parts that seems like a confined pool with fresh and cold water; the fresh gentle breeze that touches your skin with whispering sounds around your ear; the sound of chirping birds and other insects around; as well as the views of mountains, really gives relaxation, peace of mind, thanksgiving and enjoyment to human-being like me. These natural services provided by the ecosystem cannot be compared to any man-made structure.

The Interrelationship of Each System

By looking deeper into the relationship of every factor present in the area, other interactions were recorded. These include the different biogeochemical cycles that sustain the homeostasis of the environment. For instance, sun is the critical source of energy for every living organism, both biotic and abiotic factors. Without it, no one can exist, including human-beings.

The communities benefit from the oxygen produced by vegetation in the area (including us who visited them as well as in a global aspect for it cannot be confined in an area). On the other hand, plants use the carbon dioxide released by humans and animals as well as other organisms that release the same, for the process of photosynthesis to take place.

Direct Benefits Obtained in the site by the Community

Aside from the indirect value of the resources in the area, the water source supplies the needs of the Pala’wans for cooking, cleaning, bathing or swimming and other purposes. Moreover, hunting of wild animals, fishes, shrimps and other crustaceans is one of the major sources of food of the Pala’wan. The provision of these resources support the lives of the tribe. They use arrows in hunting fishes or shrimps. What is so good about them in gathering of resources is they observe proper utilization.

During the trek, Rowel, a Pala’wan, tried to hunt some shrimps for lunch. However, during those times, shrimps are not fully grown yet; thus, he did not collect any.

The Pala’wan also believe that they will suffer in the near future if the available resources are exploited. Furthermore, they believe that every place is guarded by gods and goddesses who take care of the area and they will be punished once they over-use the resources.

fishing using spear
©2013 Shellemai Roa

Intangible institutions like these lead to environmental conservation. Beliefs, cultures and traditional knowledge drive their attitudes and values toward their interaction with natural ecosystem.

Human-environment interaction is observed in every action that we do. Human activities increase or mitigate pressure on the environment. The driving forces which initiate human activities are mainly socio-economic and socio-cultural forces.

Thus, it is very important that we examine the consequences of our actions before we start to act. Consider the impacts that it will bring to ecosystem for we have a very complex system – a system that is interrelated to one another in which an action in one factor is connected to the rest of ecosystem.

©2015 April 18 Shellemai A. Roa

Categories
Ecosystem Dynamics Environment

Facts About the Goliath Grouper

Have you ever encountered a Goliath grouper while snorkeling or SCUBA diving? How does it look like? How do these magnificent fishes reproduce? Are they really big as their name “Goliath” suggest? Are they aggressive? This article answers these questions. Read on and learn about the Goliath grouper.

During one of my SCUBA diving spree in Apulit Island, a popular tourist destination north of Palawan Island in the municipality of Taytay, I met the Goliath grouper. I learned about it from a buddy diver who excitedly told me to go diving with him upon a prompt from a classmate in high school who happened to be the mayor of that town. That day actually was our high school reunion day in that isolated, white-beach a few nautical miles from the town proper.

Probably, I am lucky that the Goliath grouper (Epinephelus quinquefasciatus) I encountered several minutes when I plunged into the water was still a juvenile.  But it’s already unusually bigger than the common reef fish I see.

Behavior of Goliath Grouper

I brought with me my automatic Nikon camera encased in a plastic casing to make it water-resistant as taking pictures is a pleasure for me each time I travel. I grabbed the camera hanging by a tough nylon string around my wrist, and took a video of the Goliath grouper following my buddy. Midway the video, a grouper swam by my side then approached me with another one. You can see it below:

How big can Goliath groupers get? The ones above are just juveniles or young ones that could grow to as long as six feet. And they could weigh more than 300 kilograms! The one I saw was about two feet long.

Despite the huge size of the Goliath grouper, they seem to be docile fishes although there are reports that they do attack humans. I saw one video that says so but analyzing the situation, I thought the reason was mainly to feed, not really to attack. Here’s the video of that alleged Goliath grouper attack:

Do you agree with my observation? The moving fins attracted the grouper thinking probably that it was its prey and snapped on it. The prey was the speared fish, not the SCUBA diver who is holding the spear with the fish. It is also possible that the Goliath grouper thought the man as its competitor thus snapped on the competitor’s “tail” and swam away with its booty.

What is the life cycle of the Goliath grouper?

Goliath groupers rely on the protection of the mangrove forests because after their eggs hatch, they settle in the mangrove litter and roots. Thus, the mangroves are crucial in their survival because mangroves serve as microhabitats that prevent predators from eating the very young juveniles. When the juveniles are older, they migrate to the coral reefs and stay there for more than 40 years. When they are old enough to reproduce, the Goliath groupers migrate and spawn into the deeper water column, fertilize the eggs which then are carried by the current, hatch then drift in the currents for 30 to 80 days (Fig. 1).

Goliath grouper
Fig. 1. Life cycle of the Goliath grouper (Illustration by Jane Hawkey, IAN Image Library (ian.umces.edu/imagelibrary/)

The cycle shows that everything is connected to everything else. If something disastrous like oil spill that kills the larvae of fish like the Goliath grouper or makes the mangroves unfit for habitat to fish, then there will be lesser fish available for people to see and enjoy (if they are SCUBA diving or snorkeling tourists) and consume. I wouldn’t have seen the Goliath grouper at all.

The nearshore environment is a fragile one that should be protected or conserved considering the highly complex life that intertwine in mangrove ecosystems. The Goliath grouper is only one of the rich diversity of life that support man.

©2014 November 26 Patrick Regoniel

Categories
Ecosystem Dynamics Environment Research

18 Species of Insects from a Ceiling Lamp

This article demonstrates how deviating from a dull routine can lead one towards discovery. Find out how a little shift in one’s behavior can produce unusual information.

One night, I noticed that the ceiling lamp over our dining table got dimmer than usual. When I looked up, I saw that the central part of the lamp had a dark shade of dirt that blocked the light from going through the glass cover. Ah, the pesky insects once again got trapped on the concave part of the round plate of glass.

I got an aluminum ladder and carefully removed the rounded nut of one of the three bolts that pinned the glass covering metal holder. When I held down the glass, the following mass of winged insects attracted by the light at night greeted me.

insects
A mass of insect remains inside the glass cover of the ceiling lamp.

Instinctively, I walked towards the door to get rid of the “dirt” and clean the glass covering. On second thought, however, I paused and contemplated if I can make out something out of this mass of apparently insignificant stuff.

I went out the other door towards the porch and laid the chaotic array of broken wings. As I did so, distinct shapes and sizes of insects came into focus as I ran my fingers through it.

The picture below shows the 18 species of winged insects that I discovered from the messy collection.

insects
Species of insects sorted out from a mass of insect parts taken from the ceiling lamp.

The pile of material consisted of wasps, moths, winged termites and ants, moth, beetles, flies, plant bugs, among others. All of the identifiable stuff are insects except no. 17 which is a shed lizard skin. This indicates that lizards fed on most of the insects attracted by the light as they get trapped inside the glass cover.

Reflections from the Discovery

As we always try to find meaning to what we observe, I posed a question in my mind on the relevance of the things I’ve found. Are the things I’ve found of any value at all?

While this discovery may not be a ground breaking one, I believe that I have supplied information found nowhere else in print or online. This information may be of special significance to an entomologist.

From what I could make out from this discovery, the collection of insects in the glass covering of the ceiling lamp represents the diversity of living organisms next to our place lying next to forested lots. These insects live and die in the often inundated “bangkal” (Nauclea orientalis) forest once marked by termite mounds. These insects compose the forest ecosystem as intermediaries of nutrient cycling. They are agents that transport nutrients all over the place. Without insects, nutrients remain in the soil and will not be made available in the chain of predator and prey interactions. And these interactions influence human life (see the mango weevil story).

How significant are these insects to me? Well, they took my attention that made me climb a ladder, took pictures, and clean the glass cover of the ceiling lamp when I should have been out somewhere. It has sparked a chain of events that changed my usual routine and made online presence through this musing. And I gained enjoyment from my writing activity.

This is an exercise of being unconventional in one’s thinking. I broke a simple routine of just cleaning the “dirt” from the ceiling lamp. Being unconventional leads to discovery.

© 2014 September 21 P. A. Regoniel

Categories
Ecosystem Dynamics Environment Environmental Issues

Balabac Mousedeer: Is it a Mouse or a Deer?

Have you heard about or seen the Balabac mouse deer lately? How does it look like? Is it really a mouse or a deer? For those who are not familiar with this unique species of animal, this article is for you. Read on to find out answers to these questions.

In one of the remote islands of the Philippines, there exists an animal called pilandok or the Palawan mouse deer. Pilandok looks like a deer, but its small size at birth approximates that of a mouse. This may be the reason people call it a mouse deer. When mature, however, it’s way too large to be called a mouse. It can grow to 50 cm from the head to the base of the tail, five times bigger than the biggest mouse.

The term “mouse deer” is a misnomer because, in reality, this mammal belongs to the Chevrotain family. In French, chevrotain literally means “little goat.” Thus, it is neither a mouse nor a deer although the latter gains more semblance.

Judge by yourself where this animal should be classified by the way it looks below.

mouse deer
A mouse deer in captivity shown with its food, a fig species locally called tubog. The owner said the animal was captured while browsing for food near the coast. Photo © 2014 P. A. Regoniel

Do you agree that it looks more like a goat than a deer? Or would you rather call it a mouse?

Notice that the pupil of eye of the mouse deer is oriented horizontally. This feature characterizes goats, hence, confirming the observation that it should not be classified as a deer but to another family, i.e., the Chevrotain. This eye orientation indicates that the animal is active at night.

The mouse deer in the picture was captured way back in 2006 in Balabac Island. Allegedly, a group of locals cornered the confused mouse deer while trying to find food along the seashore amidst large stands of the firefly mangrove, Sonneratia alba. Its favorite food is a species of fig called tubog shown in the picture above.

The animal was difficult to find even while some people say it is commonly encountered along the road. In fact, the  International Union for the Conservation of Nature (IUCN) classifies the Palawan mouse deer as an endangered species. Being endemic to islands of Balabac, Bugsuk and Ramos Islands at the southwest part of Palawan Island (see map below), its remaining population is threatened by encroachment to its habitat as well as human consumption of its delicious meat.

mouse deer distribution
Population distribution range of the Balabac mouse deer in the Province of Palawan.

Another threat is that nobody has done a population study yet as far as I am concerned. Nobody exactly know how many of these animals are still in the wild. Further, according to IUCN, research is needed on its habitat requirements, threats and conservation needs.

A comforting fact is that the mouse deer are r-strategists, meaning, they reproduce fast once allowed to do so. By the time I get back to Balabac Island again, I hope to see more of them and take better pictures and videos.

Do you have additional information you want to share about the Balabac mouse deer? Write me and I’ll feature your contribution.

Reference

Oliver, W., Matillano, J. & Widmann, P. 2008. Tragulus nigricans. The IUCN Red List of Threatened Species. Version 2014.2. . Downloaded on 10 September 2014.

© 2014 September 10 P. A. Regoniel

Categories
Ecosystem Dynamics Environment Environmental Issues

Three Simple Facts About Jellyfishes

How long does it take for the jellyfish to stay alive out of sea water? Do jellyfishes melt in the rain? What ecological role do jellyfishes play in the marine ecosystem? These are three questions answered in this article. Read on to find out.

The trip to Kitu-Kito, a tourist destination north of Puerto Princesa, on board a raft made of large PVC tubings, appeared to be uneventful until tiny blobs of jellyfishes of different sizes gained our group’s attention. While a scourge to swimmers, the jellyfishes became a subject of photographic interest for me.

Various sizes of jellyfishes bob out of the water, from 5-inch diameter ones with venomous tentacles to the cute, half-inch juveniles. Here are two of them:

jelly fishes
Two jellyfishes swim about in the food container filled with water.

How Long Can Jellyfishes Stay Out of the Water?

Taken by curiosity and instinctively, our boatman caught one of the jellyfishes and placed it on the front edge of the raft. The transparent jellyfish helplessly throbbed just like a heart on the wooden surface indicating that it is alive. Its gelatinous bell (its head) looks edible.

The taste of nata de coco flashed in my mind. I had that urge to slice and eat the chewy head.

I wonder if it tastes like nata de coco? Are jellyfishes edible? The boatman said, “Yes, it is.”

The jellyfish, in fact, is a delectable delicacy in Asia. These are dried, preserved and shipped to restaurants in Japan, China, and Thailand. But I never had the chance to taste it and will not venture to do so unless everybody is eating it.

jellyfish with tentacles
The jellyfish looks like nata de coco, a chewy, translucent, jelly like foodstuff produced by the fermentation of coconut water.

“How long can jellyfishes survive out of the water?” asked one of my friends. Being a biologist, and, not knowing exactly how long it will take for these animals to stay out of the water, I retorted, “Let’s use a timer to find out.” And so we did.

Glancing once in a while and observing the jellyfish for its tell-tale throb of life somewhere in the middle of its body, we waited until no discernible movement to indicate life is evident. After a while and looking at my watch’s timer, I blurted out to the group: “48 minutes.”

Now we learned that jellyfishes could survive that long out of sea water. If it does not return within that period to the deeper parts of the sea during the rush of sea water towards low tide levels, then it gets isolated and fried under the sun or get dehydrated. Thus, it somehow distributes nutrients along the coastline as it becomes a part of the beach ecosystem food chain.

Do Jellyfishes Melt in the Rain?

Another question sprang up. “Is it true that jellyfishes melt when out of the water and exposed to the rain?”

Honestly, I could not think of a good reason why jellyfishes will melt in the rain. They’re not ice cream or made of ice. I have heard this wrong notion on many occasions. And so I simply said, “I don’t think so,” explaining a bit about the composition of animal tissue.

As if to confirm my point, by sheer coincidence, it rained that afternoon despite the generally fair weather in the morning. The raft shook with every gust of wind that pass our way and alarmed almost everyone. I have been through this situation many times in the field and I feel confident that the wind will settle in a few moments.

The raindrops fell on the jellyfish, washing it through and through. The jellyfish, of course, did not melt. It’s still there.

3. Ecological Value of Jellyfishes

Jellyfishes form part of the marine food chain. They prey mainly on the zooplankton. In turn, they are favorite diets of sea turtles. Thus, they help stabilize the marine ecosystem.

Transparent plastics thrown into sea water sometimes get mistaken for jellyfishes. This is the reason many sea turtles die as plastics block their gut and keep them full when, in reality, they are without food in their stomachs.

© 2014 September 8 P. A. Regoniel

Categories
Ecosystem Dynamics Environment

Solution to World Hunger: Eat the r Strategists

How can world hunger be resolved? The answer: through eating the r strategists! What are r-strategists and how can these animals help relieve pressure on animal populations that traditionally serve as human food? This article explores the possibility of consuming alternative food sources. 

The increasing demand for food of 7.2 billion people in the world puts pressure on conventional food sources. Thus, there is a need to explore alternative food sources. Scientists recommend the consumption of animals called r-strategists.

What are r strategists?

The so-called r-strategists are animals that reproduce so fast that chances for their populations to get depleted is much lower compared to other animals. These animals can live in unstable environments, meaning, situations and conditions where animal populations are under threat. The adaptive evolution is to have so many of their own kind. Thus saith the r/K theory that became popular in the 1970s.

For better understanding, let me define the r and the K in the r/K theory.

The r/K Theory

The r in the theory refers or comes from the word “rate.” This word reminds us to think about the rate of reproduction by which animals of this group propagate. These animals rapidly reproduce to compensate for their small size which easily become prey to other animals in the higher echelon of the food chain. And each of the offspring get less or no parental care. They can also easily adjust to environments that fluctuate. This adaptation strategy increases their chance to survive as a species.

aphids and ants
Ants and aphids are r-strategists because they rapidly reproduce and are small. These two organisms exhibit mutualism: the aphids provide the sugary honeydew they obtain from the guava to the ants while the ants provide them protection from their predators like the ladybugs (see an interesting ant defense here: http://www.pbase.com/antjes/lady_bug)

Meanwhile, the K in the theory refers to “carrying capacity.” In contrast to the r-strategists, animals that belong to this category undertake controls to their population by remaining close to the carrying capacity of their habitat. They adopt efficiency in resource use to maintain sustenance or adequate resources for each of the individuals in the face of scarce resources.

The carrying capacity of the habitat must not be exceeded to ensure the survival of these species. Thus, the K-strategists reproduce slowly, nurture their young, have larger bodies, and smaller in number compared to the r-strategists. These animals lie belong to the higher rung of the food chain, serving as “pools of nutrients” that can live in a stable habitat for a long time.

binturong
The bearcat Arctictis binturong is a K-strategist because gestation takes about 90 days and the average number of offspring per year is only two.

While recent theories like the Life History Theory supplanted the r/K theory, the terms r– and K-strategists are still used by scientists as this theory appears to be a necessary step in the study of animal adaptation to their environment. If you try to apply this theory by looking at the way animals propagate, it just makes sense. Small animals tend to produce more of their kind while the large animals reproduce slowly.

There are , however, always exceptions to any rule. For example, the bivalve Icelandic quahog (also known as black clam, Islandic cyprine, or black quahog) can live for more than 400 years! Also, the relatively small fish called orange roughy reproduce only upon reaching 20 years of age. And these fishes are estimated to live 149 years! This is the reason these fishes were not able to easily regain their population when their populations were subjected to intense fishing pressure in New Zealand, Australia and Namibia because of their popularity as food.

r-Strategists as Food?

hen and chicks
A free-ranging mother hen provides protection to its chicks.

Generally, the animals that are found acceptable by society to eat today are essentially K-strategists. These include meat coming from cows, swine, goat, chicken, among others. The last one, however, appears to lean on the r-strategists because of their short life span. Besides, these birds are domesticated and their growth is hastened to serve increasing fast food consumption demands.

We do eat fishes that are mostly r-strategists although we tend to consume too much of the wild populations. Thus, controls towards sustaining the population of these marine organisms are instituted in most countries  with intense fishing efforts.

Other r-strategists that are considered pests because of their great numbers may be considered as general food sources. For example, places like Thailand have exotic foods or foods that are generally regarded bizarre by people from other countries. These include fried crickets, earthworms, scorpions, steamed bugs, cockroaches, ant eggs and all sorts of bugs. These are all r-strategists since they reproduce rapidly but many find unpalatable despite their respectable nutritional value.

These pests are abundant in areas where people suffer malnutrition and lack of food. Is it time that these animals become a normal part of the diet? This may be the solution to world hunger. That is, if hungry people have the guts to fill their stomachs with such wiggly, wriggly and critty creatures.

Anyone ready to eat a crunchy and creamy cockroach?

References

Reznick, D.; Bryant, M. J.; and Bashey, F. ,2002. r-and K-selection revisited: the role of population regulation in life-history evolution. Ecology, 83 (6): 1509–1520. doi:10.1890/0012-9658(2002)083[1509:RAKSRT]2.0.CO;2

Schleif, M. 2013. “Arctictis binturong” (On-line), Animal Diversity Web. Accessed September 01, 2014 at http://animaldiversity.ummz.umich.edu/accounts/Arctictis_binturong/

© 2014 September  2 P. A. Regoniel

Categories
Ecosystem Dynamics Education

BioBlitz of a Disturbed Mangrove Ecosystem

Can a three-hour Bioblitz yield useful information? This article highlights the results of a quick trip to a coastal fringe. See what flora and fauna could thrive in a disturbed mangrove ecosystem.

The past two weeks had been quite busy for me as I try to keep up with two graduate and two undergraduate subjects in the university. One of those undergraduate subjects is titled marine methodology.

As an initial step in field exploration, I introduced my students to BioBlitz, a survey method where they have to record all living species within a designated area at a given period of time. The laboratory period for the class is only three hours every Friday so I designated a nearby mangrove area as the site for the activity. I intend to conduct the usual 24-hour duration BioBlitz when we go out in the field in the coming months. At best, it is only a taste of field work.

The Water as Convenient Waste Basket

We walked off at around 7:30 in the morning down to the eastern coastal fringes of the university where a clump of mangroves had grown quite well. I cautioned them to apply OFF lotion to ward off pesky mosquitoes and sandflies common in these forests. They also need to wear old shoes, sneakers or boots to keep their foot safe from shards of glass, nails or similar objects that we might step on. Incidentally, the back portion of some buildings had become dumping grounds for waste materials including bottles, old papers, and assortment of things in the office. I wonder if the administration knows about this undesirable practice.

We negotiated a slippery trail down a steep slope and were greeted by lots of floating waste carried by the waters probably from nearby places. An ordinance prohibits indiscriminate throwing of wastes but then the scene shows something is amiss in people’s attitude. The ordinance seems to work only in visible areas but not in the city’s waters.  I thought I’d spearhead a  coastal clean up and massive information campaign to prevent such build up of waste that lowers the quality of the environment.

floating waste
An assortment of floating waste materials consisting of old slippers, biscuit wrappers, shampoo sachets, instant drink pouches, old toys, sando plastic bags, empty lotion bottles, among others.

With BioBlitz in mind, we proceeded to the shallower regions of the mangrove ecosystem to inventory whatever we could find. It was high tide at 8 o’clock so we have to contend with the limited muddy strip where we could walk without fully submerging our waists. Everyone was mindful that they still have to attend their next class at 10:30 am and had to avoid getting wet all over.

Plant and Animal Species in the Narrow Stretch of Mangrove

Xylocarpus flower
Flower of Xylocarpus granatum.

I lectured on some species of mangroves and their peculiar  characteristics. Notable among these mangroves is Xylocarpus granatum, the monkey puzzle mangrove, easily identified by its pomelo-like fruit and chocolate brown petiole. The other mangrove species we found were the common stilt-rooted Rhizophora spp. , Lumnitzera littoreaAvicennia sp., and Sonneratia sp. We also noted mangrove associates like Nypa fruticans, Heritiera littorea, Excoecaria agallocha, Acrostichum aureum, and Pandanus sp. Just next to these mangroves and their associates are large trees of bangkal (Nauclea orientalis) growing at the slopes.

Below are pictures of macroorganisms found in that narrow stretch of mangrove:

marine macroorganisms
Mangrove macroorganisms (clockwise): beetle, marine cockroach and spider, cricket, mudskipper, sea slater, and sea snail.

I saw a crab but this quickly dipped underwater when I approached it. What was left was an indiscernible picture of the crustacean.

Despite the short duration of our quick survey, we had an actual glimpse of the mangrove ecosystem and its component flora and fauna. The students surely have learned to appreciate the mangrove ecosystem and came up with ideas on how they could unravel more information from what they have personally experienced; that learning and enthusiasm showed up in their field report.

© 2014 July 14 P. A. Regoniel

Categories
Ecosystem Dynamics Environment

Palawan Greater Coucal: Three Roles in the Forest Ecosystem

What is the role of a bird such as the greater coucal, a species of cuckoo, in the forest ecosystem? How will removal of its forest habitat compromise the other components of the ecosystem? This article explains how displacement and possible extinction of a bird species can impact on their habitat as well as human society.

Barry Commoner’s first Law of Ecology in his book The Closing Circle states that everything is connected to everything else. What affects one organism affects all.

If applied at ecosystem level, this means that the ecosystem’s integrity and resilience is compromised if one or more of the component parts is lost. Whatever animal or plant you find in an ecosystem will have some special role, function or influence on the other components in that ecosystem. The ecosystem works like a clock, where removal of one apparently insignificant part may prevent it from working properly or diminish the clock’s features or function.

This ecosystem principle made me ponder about the fate of the Palawan greater coucal, a bird associated with many omens in other places, that frequent the remnant forest found at the back of our house.

I took a picture of the bird this morning and feature it below. It looks as if it has just awakened from sleep as it sluggishly clambers on a branch of a tree. It cannot sustain flight just like the other birds.

greater coucal
Palawan greater coucal Centropus sinensis.

Since the land that we now occupy is classified as commercial land, in due time, the forested lot will be gone. These birds will no longer have their special place to roost and food to feed on once the remaining patches of trees that bear fruit and sustain them are cut down to make way for housing.

Do the greater coucals and other birds matter at all? What will probably happen once they are gone?

To find out how removal of the remaining forest will impact on the bird’s population, if indeed they still exist in great numbers, I will enumerate three roles that these wild birds play in the ecosystem.

Three Roles of the Greater Coucal

The greater coucal plays an important role in the ecosystem within which they live and reproduce. They serve many purposes among which are the following specific roles:

1. Seed dispersants

The greater coucals, just like the other birds, disperse the seeds of plants from fruits that they feed on. Their feeding behavior allows the distribution of plant species across a range of habitat. As a result, the plants have a greater chance to propagate their kind.

2. Aid in nutrient cycling

As the greater coucals move or fly with effort from one place to another, the birds are able to transfer nutrients that they bring with them, i. e., in their bodies. These are nutrients derived from their food. After absorbing the necessary food elements for their metabolic needs, the birds dispose of their organic waste somewhere. Their manure serves as fertilizer to plants thus starting off once again the circulation of nutrients.

Once these birds die, dead organic matter is acted upon by the decomposers. Organic matter is broken down into humus, consisting of minerals and other compounds that are available for plant use. Thus, with the aid of birds, poor nutrient areas are enriched.

3. Pest control

The greater coucals also feed on insects and even snails. Such feeding behavior help control their prey which in large numbers become pests. Economic problems can arise due to a lack of natural predator to prevent its propagation in large numbers (see the case of the mango pulp weevil).

This list enumerates at best a limited description of the role of the greater coucal in the ecosystem. A deeper investigation into its biology and behavior may uncover something that we cannot afford to lose.

What if these birds have genes that can cure an incurable illness? We will never know if we drive them out into extinction.

References

Natarajan,V (1993). Food and feeding habits of the Southern Crow-Pheasant Centropus sinensis parroti Stresemann (Aves : Cuculidae) at Pt. Calimere, Tamil Nadu. J. Bombay Nat. Hist. Soc. 90 (1): 11–16.

Payne, RB (2005). The Cuckoos. Oxford University Press. pp. 238–242. ISBN 0-19-850213-3.

© 2014 June 3 P. A. Regoniel

Categories
Cases Ecosystem Dynamics Research

Mango Pulp Weevil: A Pest Control Problem in Palawan Island

This article describes the mango pulp weevil (MPW), Sternochetus frigidus, introduced to Palawan province and discovered in 1987.  The weevil still lingers as a pest control problem that prevents local mango farmers from exporting their agricultural produce in other places. Find out how the MPW looks like and where it grows. A video is included to show how this pest behaves when disturbed and how fast it can move.

Research still has to find a long-term remedy to the problem of mango pulp weevil (Sternochetus frigidus) infestation in the province of Palawan in the Philippines where the world-renowned underground river is found.  Pest control approaches by farmers have so far been unable to eradicate the pest at source which finds the edible fleshy part of the mango as its favorite breeding place. Hence, the name mango pulp weevil or MPW.

The weevil damages a part of the mango pulp thus reduce the quality of the fruit. For more than two decades, mango growers were unable to export their agricultural produce because the mango pulp weevil will threaten the mango industry in other places.

A post-harvest pest control approach done so far to control the mango pulp weevil include irradiation as quarantine treatment (Padilla 2012). This approach appears to be more economical compared to other post-harvest pest control treatments such as the application of heat and fumigation. Local farmers also apply hit-and-miss approaches to control the weevil at source.

Morphology of the Mango Pulp Weevil

How do these pests look like? Below are pictures of the mango pulp weevil.

mango pulp weevil
Mango pulp weevil (Sternochetus frigidus) infesting mangoes in Palawan Island.

These are two of the four MPWs I have found yesterday upon slicing several fruits from our homegrown mango trees. I can feel that they have a hard texture as I turn them around for the right angles to take photos. The insect is quite small (6mm x 4mm) but switching my Panasonic Lumix LX5 to macro mode enabled me to take extreme close up shots at a distance of less than one centimeter.

Overall, MPWs have dominant brown color at the underside and an orange dorsal region mottled with dark, charcoal black bands across the pitted wings. Also, the wings have rough tiny keratinous projections that probably aid them in burrowing through the soft pulp upon maturity. The long snout has two antenna with rounded tips.

Behavior of the Mango Pulp Weevil

The two samples in the pictures shown previously were found in just one mango fruit, occupying about two centimeters of the pulp next to the seed. Initially, I thought there was only one but upon closer look, another weevil with neatly folded legs sprang to life after a minute or two.

Below is a video of how fast these pests could walk about. If given the chance, they will fly within a few minutes and enter into a state of suspended animation or diapause. Weevils do not fly great distances but usually stay close to the parent tree until the next fruiting season (Gove et al. 2007).

Consumers in Palawan can still eat at least half of the mangoes because only one side of the fruit is affected. An alternative way of consuming infested fruits is to flesh out the mango pulp and dry it (dried mangoes). The affected area is normally about 3 cm in diameter.

Preventive Measures to Control the Pest

I have not been so keen before on the presence of the mango pulp weevil in the three mango trees we have in our yard. My friend, a City Agriculturist, remarked that I should do something about the mango fruits that fall when ripe as this will infect other healthy mango trees.

Based on her remark and on the readings I made in writing this article, I recommend that the following measures should be made by consumers or mango owners.

  1. Harvest mango fruits as soon as these are mature.
  2. Remove all fallen fruits and destroy pests in infested fruit. Damaged fruits should be buried at least half a meter below the ground to prevent the weevil from completing its life cycle (Catindig and Heong 2005).
  3. Kill the pest right away when found in mango consumed.
  4. Report to authorities illegal shipments of mango from infested sources.
  5. Undertake indigenous ways to control weevil infestation such as natural fumigation or bagging using newspapers or similar material.

For researchers, studying local farmers’ practices in controlling mango pulp weevil infestation can help minimize costs associated with pest control specifically the use of synthetic pesticides. Comparing the efficacy of such practices will help identify low-cost techniques or approaches that will reduce, if not eradicate the mango pulp weevil problem.

Natural pest control measures such as breeding ants that feed on the mango weevil (Renkang and Christian 2007) may also be explored. Are there ants species in Palawan that can qualify as weevil predators? This ecosystem approach, particularly looking at the food web interactions, may be the more viable pest control option.

Is Banning Mango Export the Answer?

While banning the exportation of mango fruits from Palawan will prevent pest outbreak in other places, this caused a great loss to mango farmers in the province. Other efficient ways to control the pest must be considered or its economic impact be examined further.

Moreover, despite the infestation, it seems that only a small percentage of the mango fruits are affected. Without pesticide use, out of 300 mangoes that we have harvested at home, we found only less than 10 fruits with MPW in it. That’s only three percent.

An economic analysis may be done to look at the actual damage caused by this pest. Banning fruit exportation may not really be the answer. Rather, an effective quarantine measure should be applied.

References

Catindig, J. L. A. and K. L. Heong, 2005. Description of mango pulp weevil. Retrieved on May 27, 2014 from http://www.niaes.affrc.go.jp/techdoc/apasd/Sternochetus%20frigidus%20-B.html

Gove, T.; Joubert; J. P.; and M. S. de Beer; 2007. Literature review on mango seed weevil Sternochetus mangiferae (Fabricius) (Coleoptera: Curculionidae). SA Mango Growers’ Association Research Journal 27, 21-28.

Padilla, L. D. E., 2012. Saving the Phl Super Mango export industry from pulp weevil infestation through irradiation. Retrieved on May 27, 2014 from http://www.bar.gov.ph/digest-home/digest-archives/365-2012-1st-quarter/2055-janmar2012-phl-super-mango-export-industry

RenKang, P. and K.  Christian, 2007. The effect of the weaver ant, Oecophylla smaragdina (Hymenoptera: Formicidae), on the mango seed weevil, Sternochetus mangiferae (Coleoptera: Curculionidae), in mango orchards in the Northern Territory of Australia. International Journal of Pest Management, 53(1):15-24.

© 2014 May 27 P. A. Regoniel