A lion being collared to track its movements.

Science is a crucial component of Global Park Defense. Without ecological monitoring, we can’t possibly know what we need to protect or how to measure the success of our efforts.

For each of our projects, Global Conservation funds wildlife population baseline estimates and 4-year progress studies. Here are a few examples of how scientific studies have helped to inform Global Park Defense.

Murchison Falls: Multi-Species Aerial Baseline Surveys

In Murchison Falls National Park, Uganda, where wildlife populations are still recovering from massive poaching in the 1970s and 80s, scientists are using cameras mounted on light aircraft to count animals with Global Conservation’s support. Traditionally, these counts were conducted by an observer sitting in the aircraft, but studies have shown that human observers often fail to detect some animals, biasing the population estimates. Human observers are often overwhelmed by large herds of animals that only remain in sight for about 5 seconds. On the other hand, cameras capture a permanent image of the herd so that the animals can be more accurately counted at a later time. The use of thermal imaging can further reveal wildlife that is well-camouflaged.

By calculating camera angles, focal lengths, altitude and frame interval, scientists were able to create strips of images of a known sample size to the left and right of the aircraft. Those highdefinition images were then analyzed visually, and the scientists’ counts of animals within the photos were used to derive population estimates for multiple wildlife species, including hartebeest, elephant, giraffe, Uganda kob, buffalo, waterbuck and oribi. This camera-based method was more accurate than traditional methods.

Using this method, scientists increased the national population estimate for Uganda kob by 77%, from 77,759 to 137,736. Regular aerial counts will allow scientists to monitor population changes, allowing conservation managers to better plan for the future and informing policy makers of the status of wildlife populations.

Mirador-Calakmul Ecosystem: Jaguar Monitoring

After the Amazon, the 14.2-million-hectare Mayan Forest is the largest continuous tropical forest in the Americas and is one of the most important areas for the conservation of biological diversity in the world. This vast expanse of forest is home to the jaguar, the largest feline in the Americas, with a distribution ranging from northern Mexico to northern Argentina. Over the past 50 years, jaguar populations have been shrinking due to habitat loss and fragmentation, poaching, and an increase in human-jaguar conflict.

In order to develop a conservation strategy for the jaguar now and to understand in the future how conservation actions have impacted jaguar populations, Global Conservation recently funded a three-year scientific baseline population study for jaguar and prey in Mirador National Park, northern Guatemala and Calakmul World Heritage Park, southern Mexico.

The study’s primary objectives were:

1. To determine jaguar abundance and density at El Mirador, Guatemala, and compare to Calakmul, Mexico where studies had been ongoing for three years.

2. To determine the jaguar’s prey base and feeding habits at El Mirador, Guatemala, compared to Calakmul, Mexico.

3. To establish a baseline study to evaluate the long-term conservation of jaguars and their prey at El Mirador, Guatemala. 

Having baseline data on jaguar and prey population numbers and distribution allows us to answer questions like:

1. Five years from now, how has the implementation of Global Park Defense impacted the populations of jaguars and their prey?

2. How is jaguar distribution changing in response to changing threats, such as logging or land development at the edge of forests?

3. Might changes in jaguar numbers be attributable to changes in prey populations, or are they caused by something else?

Like other big cats, the study and monitoring of jaguars is difficult due to their large home ranges, low densities and cryptic nature. Researchers used camera traps for the study. During the dry seasons of 2018 and 2019, Cuddeback trail cameras were placed in a spatial arrangement of nine blocks of 9km2 each (3 x 3 km). Four cameras were placed within each block to capture images that would allow scientists to identify jaguar individuals by the spot patterns on their coats. The cameras were kept active 24 hours a day for 73 continuous days, with a total sampling effort of 2,628 trap days.

During the whole sampling period, a total of 25 individual jaguars were identified. Based on this information, jaguar density in Mirador was estimated at 7 individuals per 100km2, similar to jaguar densities in the Mirador-Río Azul National Park and Protected Biotope Naachtún-Dos Lagunas, Guatemala.

Altogether, these three sites with a total area of 870,815ha were estimated to have a jaguar population of 610 individuals. The results of this study confirmed that the Mayan Forest is an area of particular importance for jaguar conservation, with the highest jaguar densities north of Brazil’s Orinoco River.

Massive loss of habitat across Mesoamerica, combined with hunting and wildlife poaching for profit, is putting major pressure on the jaguar’s survival. This multi-year scientific study has obtained reliable and comparable density estimates key to monitoring wildlife populations across space and time.

For the first time in Guatemala and in the Maya Biosphere, we have the data to accurately detect jaguar population declines, estimate threats, and implement the appropriate conservation interventions needed.

Leuser Ecosystem: Drone Monitoring of Orangutans

There are two species of orangutans alive today, and they are only found in the tropical forests of Indonesia and Malaysia. These highly intelligent apes are among our closest relatives, sharing 97% of our DNA. Unfortunately, both species are highly endangered, due to rampant habitat destruction fueled by an ever-increasing demand for palm oil. 90% of their habitat has been destroyed just in the past 20 years.

The Leuser Ecosystem on the Indonesian Island of Sumatra is one of the orangutan’s last strongholds. The ecosystem spans 2.6 million hectares, almost three times the size of Yellowstone National Park. Its diverse landscape includes lowland and montane rainforests, nine rivers, three lakes, and over 185,000 hectares of carbon-rich peatlands. One of the last remaining intact rainforests in all of Indonesia, it is a crucial source of clean drinking water and agricultural livelihoods for over four million people.

Drones can be used to record orangutan nests, seen here as pale clumps of leaves at the top left corner and bottom center.

Monitoring orangutan populations in the Leuser Ecosystem is particularly challenging. Traditionally, researchers have estimated orangutan populations by walking line transects through the rainforest and counting orangutan nests. However, their habitat is dense and difficult, requiring significant time and funding. Sometimes, researchers need to cut a path through the dense undergrowth, and they can typically only walk two kilometers of transect per day. With total transect lengths reaching 100km or more, research teams often spend the better part of a month conducting one survey.

Methods that are often used to estimate populations of grounddwelling species aren’t of much use; because orangutans move through the trees in threedimensional space, camera traps are unlikely to capture them. Due to these challenges, researchers have been unable to conduct population counts at a high enough frequency to accurately monitor changes.

Researchers at Conservation Drones figured out that unmanned aerial vehicles (UAVs) could address this problem. By flying fixed-wing UAVs in a pre-programmed pattern above the forest, researchers could capture thousands of high-resolution images of the forest canopy. They could then scour these images for orangutan nests, producing an accurate count of the number of nests in a given area. Although these nests must currently be counted manually, researchers are working on training artificial intelligence to detect nests in the images. 

Researchers chose fixed-wing UAVs because they are faster than quadcopters and can fly further on a single battery. Even though fixed-wing UAV surveys are faster and cheaper than walking transects, able to fly 50km in 40 minutes, they tend to differ from foot-transect surveys in how many nests they detect. Therefore, the first step to implementing this new technology was to conduct both survey types in the same area and then compare the results. After doing this enough times, researchers were able to calculate the error and accurately estimate populations using UAV surveys alone.

Most recently, researchers have begun to add thermal cameras to the drones, helping them to detect orangutans even more reliably using their heat signatures.

This new method adds to the many uses of UAVs in conservation, including mapping land use types and forest cover, and anti-poaching.

Mana Pools: Carnivore and Elephant Collaring

Wildlife tracking collars are an important part of scientific monitoring at Mana Pools National Park, Zimbabwe. Our partners at the Bushlife Conservancy are working with ZimParks to build up a research program in Mana Pools and its surrounding areas. As of mid-2020, they have collared three lions, three hyenas, and one leopard.

It is hoped that by collaring these predators, their movements can be tracked, den sites marked and information on genes and diseases can be collected. Bushlife is hoping to get collars on another two lions, two hyenas, three leopards, four wild dogs, and one cheetah this year. This will open up research opportunities in the park for both local and international students and help inform their conservation efforts.

The researchers also re-collared three iconic elephant bulls to help identify them as iconic and prevent hunters from shooting them in the areas adjacent to Mana Pools. Although elephants with collars may legally be hunted, the collars are a way of safeguarding these animals as they act as a deterrent to hunters. In this way, Bushlife aims to conserve the large tusk gene in the elephant population. Meanwhile, female elephants are collared in order to monitor their movements for research purposes. Two more collars will go on elephants this year.

For this type of work, there are several different types of collars that can be used, each of which has advantages and disadvantages. 

Radio collars, or VHF (very high frequency) collars, emit a pulsed radio signal that can be picked up by a receiver and antenna, allowing someone to locate and observe the animal on foot or with a vehicle. While radio collars allow an observer to find an animal, they do not store data on the animal’s movements. Any location data must be taken manually by the observer.

GPS/GSM collars, on the other hand, allow continuous collection of location data because the location is stored within the collar or sent by cell phone GSM connection to the researchers at regular intervals. For that reason, GPS collars are better for collecting home range data, as they give a more complete picture of the animal’s use of the landscape at all hours. GPS collars work by sending signals to networks of satellites in orbit around the earth, which are able to pinpoint the precise location of the animal and track its path as it moves.

Satellite collars are similar to GPS collars, but are able to directly transmit the data to a user’s email or server. This is especially advantageous in areas with little or no cell phone signal, as in many wilderness areas.

GPS and satellite collars transmit the animal’s location at preset intervals rather than on demand, but they may also have a VHF attachment to allow researchers to track the animals on the ground in real time as well. This is one benefit of VHF -- with a standard GPS or satellite collar, researchers usually cannot find the animal in real time to make behavioral observations.

One major consideration in choosing among these options is cost. Radio collars tend to cost about US$350-650, not including the cost of antennas and receivers. GPS collars are more expensive at around $1,000-3,500, with satellite collars being the most expensive option at around $4,500. Radio collars tend to have a longer battery life than GPS or satellite collars.

Some collars are equipped with studded plates that are designed to protect animals from becoming injured if a snare gets wrapped around their neck. All three collar types can be programmed to transmit a special signal if the animal has not moved for a predefined period of time, called a “mortality signal.”

To help inform conservation decision-making, GPS and radio collars can help answer research questions like:

1. How does wildlife move in response to disturbances such as tourism, logging, or poachers in the area?

2. What is the home range of a given wildlife species in the study area, and consequently, how might habitat fragmentation affect its survival?

3. Which are the most dangerous areas for wildlife (are they consistently becoming injured or dying within a particular part of the protected area)?

4. How is a relocated animal adapting to its new area, and is relocation successful at keeping problem animals away from human settlements?

5. How do seasonal changes, natural disasters, or interspecies interactions affect animal movements? 

Collaring one individual in a group of social animals like lions, spotted hyenas and wild dogs can help provide information about the whole group. In solitary animals, a collar can only provide information about the individual. In any case, wildlife collars are an important scientific tool for conservation.

Palau Northern Reefs: Monitoring Fish Populations

Palau’s ocean riches are many; its coral reefs are considered one of the seven Underwater Wonders of the World. In just one day, it’s possible for a diver to see a menagerie of megafauna, from giant clams and manta rays to sea turtles, dugongs and fierce saltwater crocodiles that grow up to 4.5m long.

Palau’s technicolor reefs contain more than 350 hard coral species, 200 soft corals, 300 sponges, and 1300 species of reef fish. However, there is concern across Palau that fish stocks are declining, especially with booming tourism and the resulting demand for fresh seafood.

Illegal fishing and commercial exploitation is threatening traditional communal fishing systems. In a given year, Palau faces 50 to 100 incursions by foreign pirate vessels. Some local community members also enter no-take MPAs illegally, often at night. As fish stocks decline in South Palau due to heavy domestic and international fishing, the protected Northern Reefs will be increasingly targeted by poachers.

The sustainability of a given fishery is determined not only by the sheer number of fish harvested, but also by the size of those fish. Harvesting smaller fish means removing individuals before they have the chance to breed, which reduces the overall ability of a fish population to replenish itself after a fishing season. Eventually, the stocks might collapse.

Over recent years, fisheries stock assessments conducted in the waters of Kayangel and Ngarchelong showed the area is grossly overfished. According to fisheries data, nearly 70% of fish caught were immature or juvenile; fish are being caught before they have the chance to mature and reproduce.

In order for a fishery to be sustainable, enough breeding-age fish must be left to replenish their population. Should the situation continue as-is, the fisheries will no longer be able to support the livelihoods of communities or provide an economic benefit to Palau.

All of this means that fishing is becoming increasingly unsustainable in Palau, threatening the livelihoods of Palau’s fishermen. Resolving this situation requires both effective regulation and enforcement.

Governments usually regulate the number and size of fish that fishermen are allowed to harvest, but to set those regulations, government officials must rely on scientific studies to determine what is sustainable. To understand whether current laws, regulations and enforcement were sufficient, or whether they were allowing fish stocks to decline, scientists at the Coral Reef Research Foundation studied the size of fish that were being harvested by Palau’s fishermen.

The researchers used a compact 3D camera to film each fish that was caught at a particular landing site in Palau. Then, they used a specialized software called EventMeasure-Stereo to automatically measure the size of those fish. This method allowed them to quickly measure a large number of fish without touching them or interrupting the fishermen’s work. Once they had these data, they compared them to historical data on the size of fish caught in the 1980’s and 90’s.

They found that the average size of most fish species captured has decreased, indicating that fishing of these species is approaching unsustainability. The number of large fish caught has also declined markedly, and many of the fish being caught are immature. For three common fish species, the scientists found that fishing pressure was already far above the sustainable rate.

After this study showed that fish stocks were in decline, the Palau Fishermen’s Forum supported recommendations to (1) create a list of ten priority near-shore fish species that will be the targets of legislative reform proposals; (2) determine optimal, scientifically derived size limits for each of these species that protects more breeding-age fish; (3) identify spawning seasons, spawning sites, and other critical habitats for these species, and develop strategies for adequate enforcement; and (4) explore marine use zoning options that delineate areas for conservation, hatcheries, and specific types of fishing. It is hoped that these activities will help set reef fish stocks back on the path to recovery.

With adopted resolutions and public awareness of the problem, it is hoped that over time we will see improvement in the reef fish stocks. What’s more, the data generated now can be used to assess the effectiveness of these interventions in the future. For that reason, this study also highlights the usefulness of historical data collection. The fish size data collected in the 1980s and 90s may not have been directly informative at the time, but it now provides a good baseline to assess changes over time.

It would also be beneficial to increase studies on the size at maturity of fishes in Palau, as without this parameter a biologically relevant size limit cannot be recommended.