LATEST NEWS - Frontier Costa Rica

FRONTIER COSTA RICA: PRIMATE STUDIES

Primates on the Osa Peninsula constitute an important part of its biodiversity. The four main species found in this area are the Central American Squirrel Monkey, the Mantled Howler Monkey, Geoffroy’s Spider Monkey and the White-faced Capuchin. In the most recent assessments by the IUCN, two of these species have been listed as endangered and vulnerable, while primate population numbers as a whole exceed a rate of 50% decline over the past 45 years. The role of primates in tropical forests is essential for maintaining floral biodiversity. The diets of most primates in fact are principally constituted by fruits. Due to their agile nature and moving across areas jumping from tree to tree, they perform an important role as seed dispersers, maintaining plant biodiversity.

The Osa Conservation and Frontier have been working on primate studies for the past few years. Recently however, the project methodology had changed trying to encompass surveys of all species present in the area. This will allow field staff to have a better idea of the behavioural routine these animals perform on a daily basis. Understanding the behavioural time budgets as well as the ecological necessities of individual species, is essential for developing conservation strategies targeted for each specific primate species.

The method employed in the last phase was kept consistent with the work being undertaken by Osa Conservation. The team has been revising trail routes and transects to maximise the area being surveyed when observing individual troops. While observing the troops all behaviours were recorded. Extra information was collected when possible, including the number of males and females and sex of the juveniles. One of the long- term aims of the project is in fact to determine the number of troops in the area of the different primate species ultimately using a GIS model to map their movements.

The results for this phase are still limited although patterns in dominant behaviours for each species are already noticeable. Over the next phases the team will continue to work on the study to be able to draw further conclusions on these important components of the wildlife of Costa Rica.

By Eleonora Arcese

Frontier runs a number of volunteer projects in Costa Rica and has a huge range of opportunities to volunteer in the Americas



FRONTIER COSTA RICA - SEA TURTLE PROJECT SHOWS NEW INTERESTING RESULTS

The Osa Conservation and Frontier Costa Rica turtle project has been producing some interesting results over the last survey phase. The patrolling of beaches and the monitoring of nesting females have allowed the team to gather once again data regarding the mysterious ecological behaviour of these fascinating animals.

In 2003, Osa Conservation began patrolling the beaches of the Osa Peninsula aiming to deter poachers and predators to ensure the long–term conservation of turtles nesting on these shores. It was subsequently joined by Frontier with the objective of patrolling the beaches and gathering together important data on turtles coming to nest on these sites. The overall aim of the project is to be able to create a database with relevant annual information on the nesting cycles of various species of turtle present on this peninsula. In addition, data is being gathered relating to hatchling success, predation levels and methods of protection, location of the nesting sites and size, health and species of turtle and flipper tagging individuals. The patrol area covers approximately 8 kilometres, and comprises a stretch of land between Playa Piro and Playa Pejeperro.

There are two species of marine turtle known to nest frequently on Playa Piro and Playa Pejeperro: the Olive Ridley turtle (Lepidochelys olivacea) and the Pacific Black turtle, also known as Pacific Green (Chelonia mydas agassizii). Leatherbacks (Dermochelys coriacea) and Hawksbill turtles (Eretmochelys imbricate) have been seldom sighted as they nest less frequently on these beaches. The Olive Ridley turtle is the more commonly sighted of the two species. Pacific Greens come ashore to nest between December and March, whereas Olive Ridley Turtles tend to nest from July until September. In some areas the two species will tend to nest together, where hundreds of turtles swim ashore at one given time. This extraordinary event is known as “arribadas” (Gaos et al, 2006; Savage, 2002).

Over the past few weeks, the team has been concentrating solely on morning patrols as the Oliver Ridley turtles which nest during the night have stopped arriving at the beaches, as their season is now over. The Pacific Green season however, is currently ongoing and this species tends to lay its eggs during early morning hours. The team had also explored the difference in nest position between the two species. As predicted the Pacific Greens tend to nest much closer to vegetation stands with respect to the Olive Ridleys. An interesting finding of the study was the very high proportion of false crawls present on the beaches during this phase with respect to previous ones. False crawls, or unaccomplished nesting attempts, may be occurring due to a number of different factors, usually strictly related to the environment. The higher proportion or false crawls by Pacific Greens during this phase could be related to their sensitive nature when choosing a nesting site and their low tolerance to disturbance.

The team also recorded the presence of leatherback turtles during this phase. This species is usually very rarely seen, which makes the outcomes of this phase extremely successful. Furthermore, predated nests have not been recorded so far this year on either beach, although it is early in the year. There have also been some changes especially with regards to the domestic dogs on Pejeperro beach. A house formerly inhabited by locals is no longer occupied and therefore it is possible that the dogs have moved further away in search for food. Tracks are still seen regularly however, predated nests have dropped in numbers. Hopefully this will continue throughout the year.

By Eleonora Arcese

Frontier runs a number of volunteer projects in Costa Rica and has a huge range of opportunities to volunteer in the Americas



FRONTIER COSTA RICA - CAMERA TRAP UPDATES

The site of study for this project in Costa Rica, the Osa Peninsula, has been described as an area of unique ecological importance given the high faunal diversity it supports. Amongst these diverse species, one may encounter jaguars (Panthera onca), cougars (Puma concolor) and white-lipped peccaries (Tayassu pecari). However, such species are elusive to study since they are highly sensitive and cautious in the presence of humans. As such, traditional sampling methods that have been employed to study other species in this project cannot be utilised for these animals.

In order to overcome this situation, camera traps have been deployed on a variety of trails in the study area in order to capture photographic evidence of these species. Such a method is highly advantageous for both the researcher and the animals, as it allows us to monitor these species with minimal disturbance. Furthermore, since such species are generally nocturnal, it allows the researchers to continue their data collection throughout the entire day with minimal effort. Camera traps used in this phase were all Bushnell Cam trophy models, which were set to the highest sensitivity in order to take three photos in quick succession, each at a second apart and then programmed to not take pictures again for a further ten seconds. Cameras have been attached to trees at a suitable height in order to capture most animals passing by. The camera traps are checked approximately once a week in order to minimize disturbance in the area which may contribute to negative results, whilst at the same time ensuring that the batteries are charged as to not compromise any possible photographs.

Results obtained so far have been highly promising, with some very exciting shots of a variety of species including a subspecies of cougar native to Costa Rica (Puma concolor costaricensis) and several collared peccaries (Pecari tajacu). This on-going project is expected to shift in the area it covers, as it would potentially allow the researchers to estimate population sizes for such species, as well as their territory ranges. It is also anticipated that this sampling method will be applied to other projects in Costa Rica, such as the study on the Neotropical Otter.

By Antoine Borg Micallef

Frontier runs a number of volunteer projects in Costa Rica and has a huge range of opportunities to volunteer in the Americas.

COSTA RICA FOREST - FOREST RE-VEGETATION

Deforestation is a significant threat to the wildlife of Costa Rica with large areas of land having been cleared for arable agriculture, plantations and buildings. These were the main causes of forest clearance between 1986 and 1991 when deforestation rates were estimated to be at 4.2%. The majority of people living in Costa Rica earn a living through agricultural means and so land clearance has been an important factor for many years with clearance rates being at their highest in the 1950s and 1960s.

Deforestation is a danger to wildlife and habitats because not only does it remove important ecosystems that support many different species but it also contributes to fragmentation of forest areas. This impacts wildlife by leaving them with smaller and smaller areas for survival which may not be large enough to support the population; it also removes corridors to enable wildlife to move between different areas leaving them isolated. In Costa Rica, the Cerro Osa area and its surrounding forest habitats are an important corridor which connects the Corcovado National Park to surrounding areas within Costa Rica. If these corridors are lost or become too small, larger mammals, especially big cat species such as puma and jaguar will be stuck in isolated populations without the range size they need as well as reducing the diversity of their gene pool.

The Frontier Costa Rica Forest Team have identified deforested locations within their study area, specifically sites that have been abandoned in recent decades and which were once used as land for plantations. These areas are starting to resemble primary forest but are lacking in many of the important species native to the area with the current growth primarily being of low biodiversity. So, Frontier are collaborating with the local Osa Conservation group to initiate a re-vegetation programme so ensure that a more diverse, natural forest system forms for the benefit of the local wildlife.

Native species are being used and seeds taken from local areas to establish seedlings within the nursery; once the saplings have germinated and are well established they are planted outside and will eventually be established within the deforested areas of plantation. The most abundant species that are being used are: Bateo (Muntingia calabua), Cristobal (Ayenia limitaris), Sapote (Pouteria sapota), Maria (Aglaonema sp), Cedro (Cedrela fissilis) and Dulce (Pithecellobium dulce). In this past phase, the team have been working on bagging up soil, weeding the saplings in the nursery and collecting the relevant seeds from nearby forest areas to ensure that the plants will be ready to be planted soon and to maintain a good stock of plants.

In the long-term, it is hoped that the re-establishment of native plant species will encourage more wildlife to return to the area, and that present faunal populations may increase.

Frontier runs a number of volunteer projects in Costa Rica and has a huge range of opportunities to volunteer in the Americas.

CHANGES TO THE PRIMATE MONITORING PROGRAMME

Primates constitute an important part of the biodiversity on the Osa Peninsula. There are four species present in the Osa region, the Central American Squirrel monkey (Saimiri oerstedii), Mantled howler monkey (Alouatta palliata), Geoffroy’s spider monkey (Ateles geoffroyi) and White-faced capuchin monkey (Cebus capuchinus). These primates perform important roles as seed dispersers and are therefore crucial in maintaining plant biodiversity in the forests of the Osa Peninsula.

The SEE research programme in Costa Rica has been monitoring the behaviour of these primates in varying habitat types, including both primary and secondary forest, at various times of the day. Recently, the team have adjusted the methodology providing a more meticulous surveying approach. The new methodology includes standardized categories for recording behaviour and a standardized method of recording weather conditions. When recording behavioural data a focal individual is picked from the troop and instantaneous sampling is used to record their activities every 30 seconds over a 5 minute period. This allows the team to be analyse the average percentage time that primates spend on each activity. The standard behaviour categories are; Locomotion, Resting, Foraging/Feeding, Social Interaction (grooming, sexual behaviour or close contact within species), Aggression, Behaviour towards humans (throwing sticks, shaking branches both directed at towards the observer) and Other (any behaviour not falling into the above categories).

This phase the team have found that the majority of primate species are found in secondary forest and are more frequently sighted in the early morning. Furthermore, results from the previous couple of phases show fluctuating figures in species abundance between secondary and primary forest, this could be due to environmental factors, for instance, it is currently the wet season this phase, and this will have an effect on the fruiting trees and therefore primate abundance.

From the latest Science Report.

Frontier runs a number of volunteer projects in Costa Rica and has a huge range of opportunities to volunteer in the Americas.

RIVER OTTER MONITORING

Frontier’s research programme in Costa Rica began in July 2009 in collaboration with the Osa Conservation at the Osa Biodiversity Centre. Part of the programme is concerned with monitoring the habitat distribution of the endangered species of Neotropical River Otter (Lontra longicaudis).

The Neotropical River Otter is sparsely distributed across Central and South America. For many years these animals have been persecuted by hunters for their extremely valued pelt. This activity has caused the extinction of various populations across parts of its former range. Today this species is listed in CITES Appendix 1 and in the IUCN Red List of Threatened Species, however, illegal hunting still occurs in numerous parts of Central and South America.

Lontra longicaudis is a solitary species only interacting with other individuals during the breeding season. They are commonly found living in swamps, lagoons, and fast- flowing streams. Although this species has been able to adapt to disturbance (being reported to inhabit irrigation ditches and sugar cane plantations), there are numerous threats it still faces today. As for most other tropical rain forest species, habitat destruction is the main concern for most scientists studying the Neotrpoical River Otter. Deforestation, agricultural expansion and water pollution have had a negative impact on otter population numbers in certain areas.

The aim of Frontier’s lead research programme is to contribute with significant data to the lack of knowledge there is about this species. The research focuses on trying to understand this species habitat distribution, usage and preference on a two kilometre stretch of two different rivers: Quebrada Coyunda River and Piro River. Most recently the methods employed for data collection have been based on recording the presence of otter trespassing in different river sectors. Scat and track sightings have been recorded using GPS on 20 metres sectors on each river stretch. Surface suitability has been described using the Environmental Agency River Habitat Survey methodology (Environmental Agency, 2003). Direct observations have been made by using Bushnell Trophy Camera traps placed where scats or tracks had been recorded during the study.

Although the data is still in its early stages, the results show various trends especially regarding the choice of surface used for latrines (otters preferred logs to other surfaces). Otters have been occurring in certain river sectors with higher frequencies compared to other sectors sampled for scats and tracks. Existing wisdom on Mustelids suggests that otters use latrines to scent- mark their territory and for mating signals. It is therefore possible they have been repeatedly using particular sectors of the rivers to mark their territorial range against other males, or for communication with females. Furthermore, studies have shown that otters tend to return to places where there is most likely abundance of food, or in the case of females, if their holts are nearby. Females will emerge from their holts on rare occasions and will only use latrines during the breeding season.

Scat and track recording does not give an accurate estimate of otter population numbers present in a certain area. Scats and tracks could belong to the same individual, as otters have been found to travel up to 40 kilometres away from their home ranges. However, the preliminary results gathered by this study do imply that the otter population on these two river stretches could give a good indication of habitat preferences and distribution of otters across the whole length of the two rivers. Further studies with the aid of possible granting could ensure the study to continue in the future allowing conservation efforts and management strategies to be implemented to protect this vulnerable species.

By Eleonora Arcese

Frontier runs a number of volunteer projects in Costa Rica and has a huge range of opportunities to volunteer in the Americas.

TURTLE EGG DEPREDATION BY DOGS

During the last phase in Costa Rica study of turtle nesting sites has begun to include data on predation. Although in its early stages this study has seen many observations of disturbed nests and predated eggs on both Piro and Pejeperro beaches. Around the nests several different species tracks have been noted, including coati, dog, and vulture, these species have been known to predate on turtle nests in Costa Rica and cause significant population damage (Fowler, 1979). Depredation of turtle nests is a big threat in terms of their survival as many introduced species may be new enemies to the nests.

The study in Costa Rica evaluated the tracks around disturbed nests and found that the majority of disturbance was most likely caused by dogs. There was a peak in predation between sectors 27 and 41 of Pejeperro beach which was at first not understood by locals and staff. With this in mind they surveyed the local area and discovered that a house located on the edge of Pejeperro beach was home to seven domestic dogs which the owner allows to roam freely. This house is located in sector 36, right in the middle of the peak predation zone, leading the Costa Rica team to believe that these dogs may be a cause for concern when hatching season begins, as studies have shown that dogs are more likely to prey upon nests with hatchlings than with unhatched eggs. In extreme cases, such as in Florida, there were years where up to 95% of nests were predated, mainly by dogs, but after removing the animals the decline in disturbance was rapid. In 2002 it was revealed that these actions saved around 120,000 turtle hatchlings and secured survival of the species in the area.

In Costa Rica, after reviewing the tracks again and confirming the data with the house owner it was decided that 4 of the 7 dogs should be removed, to allow the owner to have time to watch each dog an reduce predation in the upcoming months. As of yet it is too early to tell whether this plan has been successful, but we look forward to good news from the field on this front.

The team has also been looking into further mitigation methods in case the damage was not reduced by these actions. Ideas such as campaigns to raise awareness of the effects of dogs on turtle populations have been used in other places, such as Vanuatu, to encourage the communities living in close proximity to turtle nesting site to be aware of their dog’s movement or keep them enclosed while they are unable to do so.

By Grace McConnell

Frontier runs a number of marine conservation projects, including volunteer projects in Costa Rica and a huge range of opportunities to volunteer in the Americas.

THE NEW BUTTERFLY PROJECT

Butterflies are one of the most diverse groups of invertebrates, with twice as many species of butterflies as terrestrial birds and approximately three times the number of mammals and reptiles. Nearly 90% of all butterfly species live in the tropics; it is surprising therefore that extremely little is known about tropical butterfly ecology in comparison to their temperate counterparts. In Costa Rica alone there are at least 1,250 species of butterflies.

Butterflies belong to the order Lepidoptera (the order of insects that includes moths and butterflies), Lepidoptera means ‘scaly wing’ and butterflies are characterized by their large, often colourful wings. Butterflies also play important ecological roles in tropical ecosystems, as they are major pollinators of plants and are also prey for a large number of animals. They are also effective indicator species, and have been used to monitor human degradation, land use change and climatic shifts.

In this phase, the new butterfly project in Costa Rica is monitoring the Lepidoptera with a special focus on habitat diversity and human disturbance. The team used two different methods to collect species diversity and abundance data, these included canopy traps, and sweep netting, at two different surveying sites. The first site was a grass clearing and the second was a river habitat. The Frontier Costa Rica research team found a difference in diversity and abundance between the two different sites, the grass clearing yielded over 45 individuals, was four times the number of individuals found at the river habitat. As well as having a higher abundance, the grass clearing also had double the species diversity.

One possible explanation for the higher species abundance and diversity in the grass clearing could be due to the different microhabitats. This project is still in its early stages and due to the wet season beginning canopy traps cannot be used until November. Nevertheless, this project aims to survey many more different habitats in the survey areas in order to gain a better understanding of tropical butterfly ecology.

By Marielle James

Frontier runs a number of marine conservation projects, including volunteer projects in Costa Rica and a huge range of opportunities to volunteer in Africa.

OLIVE RIDLEY TURTLE HATCHLINGS

Frontier Costa Rica Staff and Volunteers are seeing more and more turtle hatchlings in the last few weeks. The two beaches on the Costa Rica camp, Playa Piro and Playa Pejeperro are the nesting grounds for two turtle species, the Olive Ridley (Lepidochelys olivacea) and the Pacific Green (Chelonia mydas agassizii).

The hatchlings sighted over the last few weeks have been predominately Olive Ridleys. Olive Ridley turtles breed between July –December. Olive Ridley’s are famous for their synchronized nesting in mass numbers, termed arribadas in Spanish, meaning “arrival”. During the arribadas, tens of thousands of female turtles nest during the same 3-7 day period once a month.

Marine turtles are a unique class of species. They play vital roles in ocean and beach/dune ecosystems. For example, the Green turtle (Chelonia mydas) forages on seagrass beds that are on the sea floor. They help keep the seagrass short which maintains healthy seagrass beds, which are essential breeding and nursery grounds for many species of fish and other marine life. The Olive Ridley turtle is the more common of the two species found in Costa Rica, despite this Olive Ridleys are classified as Vulnerable and the Pacific Green turtle is listed as Globally Endangered on the IUCN Red List.

One of the research areas for Fontier’s Costa Rica team is predation on turtle nests. On the beaches of Osa Peninsula, turtles are threatened predominantly by predation from dogs, coatis and humans. It was only relatively recently in 1963 that the Costa Rican government provided legal protection against the collection of turtles and their eggs. Despite this protection, illegal trade of turtle eggs still continues. Recent research has found that dog, vulture and coati tracks have been noted next to some of the predated nests. Predation and the illegal trade of turtle eggs are some of the main causes of turtle population decline.

The increased sightings of Olive Ridley hatchlings are encouraging evidence of the importance of protected areas in marine turtle conservation. The increasing interest in ecotourism in Costa Rica, which provides locals with an alternative source of income instead of poaching eggs and turtles for their shells and meat, will further increase marine turtle protection. Ecotourism is other countries, has resulted in dramatic increases in turtles nesting on the protected beaches and it is hoped that this will be a similar case for marine turtles in Costa Rica.

By Marielle James

Frontier runs a number of marine conservation projects, including volunteer projects in Costa Rica and a huge range of opportunities to volunteer in Africa.

PUMA CAPTURED ON CAMERA TRAP

Frontier Costa Rica has captured their first ever big cat on camera. Costa Rica’s camera traps have captured four photos of a Puma concolor, commonly known as a puma, panther, cougar, mountain lion and mountain cat.

The puma has the largest range of any terrestrial mammal in the Western Hemisphere. It occurs in every major habitat in the Americas throughout Canada, the US, Central and South America, with different regions using the variations of the puma’s common name. The puma is a reclusive cat and usually avoids people.

Although the puma is categorised as a species of least concern according to the IUCN (International Union for Conservation of Nature), population numbers are in decline. Puma habitats are also in declining as a result of habitat loss and fragmentation. Their dispersal is also restricted due to heavily travelled roads that prove major barriers.

These sightings are ongoing proof of the revolutionary impacts that camera traps are having on terrestrial conservation research, capturing images of secretive animals and animal behaviour not previously witnessed by humans.

By Julia Crabbe

Frontier runs a number of marine conservation projects, including volunteer projects in Costa Rica and a huge range of opportunities to volunteer in Africa.

THE NEW DRAGONFLY PROJECT

Dragonflies (Insecta: Odonata) are amongst the most attractive and captivating groups of insects. They are known to occupy a wide range of aquatic habitats in forests which include seasonal and permanent pools, seasonal and permanent swamps, lakes, streams, rivers and springs. Their bright colors, aerial acrobatics, large body size and unique mating patterns capture scientist are as well as tourist’s attention. Biological wise, they can be used as indicators of ecological health, ecological integrity, environmental change and the hydrological dynamics of water bodies. Other advantages of using dragonflies as bio-indicators could be serving as umbrella species representing both aquatic and terrestrial assemblages.

In this phase, Frontier Costa Rica Forest programme studied the dragonfly assemblage of Osa Conservation’s land with the overall aim of filling some gaps in knowledge of Central American Odonata. The objectives were to collect baseline presence/absence data in order to detect changes in habitat quality that may have gone unnoticed by humans. In addition, the team looked into habitat use and seasonality and created a photo ID guide of the species present in the area to facilitate future research efforts.

To account for both seasonal and daily activity patterns, sites ware surveyed in different timeslots between January 30th and May 17th 2012. Sampling was standardized by 30 minutes of intense sampling. Adult dragonflies were netted, measured, photographed and released. Other information including sex, behavior, and height of perching were also recorded.

A total of 314 individuals have been captured and identified representing 53 species, belonging to 29 genera and 9 families. Libellulidae and Coenagrionidae families stood out for having the most genera and species. The two families combined comprised 73% of the species found in the area. The present survey yielded 19.7% of the species currently known from Costa Rica. This is an exceptional high figure considering that the surveys were conducted in a relatively small area of lowland forest. The most interesting find was a female member of the Palaemnema genus (Family: Platystictidae) which is likely to be an un-described species. Because this species was encountered only once, no specimen could be taken for DNA analysis and formal description. More work on species distribution, seasonality and between site comparisons is on the way and will be published in future reports.

By Julia Crabbe

Frontier runs a number of marine conservation projects, including volunteer projects in Costa Rica and a huge range of opportunities to volunteer in Africa.

THE NEOTROPICAL RIVER OTTER (LONTRA LONGICAUDIS)

This fascinating species leads a solitary lifestyle and lives in a variety of habitats from swamps to streams to lagoons in Central and South America. It is known for being able to adapt well to habitat disturbance and there are reports of the species even inhabiting irrigation ditches in rice and sugar plantations.

The Neotropical Otter is listed in Appendix 1 of CITES as its populations have long been hunted for their pelts, in some areas to such an extent that the river otter became extinct in many areas of its former range. The species is protected in many countries, including Costa Rica, where Frontier is currently conducting research into the habitat preferences in order to contribute to the gap in knowledge on the habitat use and population structure of Neotropical Otters. Despite its protected status, the Neotropical Otter is still hunted illegally. Other threats to the otters include agricultural activities, pollution of waterways and deforestation.

Frontier is currently surveying stretches along both the Quebrada Coyunda River and Piro River. The team is looking for scat and track signs as well as setting up camera traps in the hopes of capturing images of the otters and learning more about the composition of the local populations and potentially recognise individuals.

Due to the shy and elusive behaviour of the river otter, they are rarely observed. Because of this, there is very little information on Lontra longicaudis and thus they are listed as ‘data deficient’ on the IUCN (International Union for Conservation of Nature) Red List. The otter has been assigned this status since 2000 due to ongoing uncertainties about the effects of different anthropogenic threats across its range on the rates of population decline. Until now, there have been no systematic studies to evaluate the size of the population and no standardised information about changes in the extent of occurrence or area or occupancy. The species is suspected to be threatened, but further research must be conducted to confirm this. In this way, the research that Frontier’s Costa Rica team is conducting is vital for the conservation of this species.

If you are interested in volunteering to help conserve the Neotropical River Otter and other species, Frontier runs a Costa Rica conservation programme.

By Lea Fraenkl

Frontier runs a number of marine conservation projects, including volunteer projects in Costa Rica and a huge range of opportunities to volunteer in Africa.

FRONTIER COSTA RICA – SEA TURTLES

Sea turtles are a unique species. Not only are they a flagship species due to their iconic nature, but they are also an excellent indicator species for climate changes thanks to their temperature dependent sex determination.

Frontier’s research programme in Coast Rica is situated on the Osa Peninsula and there are two species of marine turtle known to nest frequently on two of the beaches being surveyed by the Frontier team: the Olive Ridley turtle (Lepidochelys olivacea) and the Pacific Green turtle (Chelonia mydas agassizii). The Olive Ridley turtle is the more common of the two species; nevertheless, it is still listed as ‘vulnerable’ by the IUCN (International Union for Conservation of Nature). The Pacific Green turtle is listed as globally endangered following significant population declines worldwide, with a 48-67% decline globally over the past three generations.

Sea turtles take decades to mature (for example, females of the Pacific Green Turtle (Chelonia mydas agassizii) can take up to 26 years to reach sexual maturity) and it is this late maturation, along with anthropogenic threats such as beach development, long line fishing and pollution, that mean sea turtles populations are highly vulnerable and often unstable.

Currently, one of the research areas for Frontier’s Costa Rica team is species that are especially sensitive to climate change, such as sea turtles. Like many cold blooded reptiles, sea turtles exhibit temperature dependent sex determination, which means that increased temperatures create a sex bias in favour of females. Increasing temperatures therefore bring with them the concern that there may be too many female sea turtles, which could result in the collapse of entire populations.

Poaching and the illegal trade of turtle eggs are some of the main causes of turtle population decline. In the period of 1950 to 1970, turtle poaching was at its worst, with a half of the world’s turtle catches being made in Mexico (up to 350’000 turtles annually). Habitat loss is often the result of tourism, which is another threat to sea turtle populations. On the beaches of the Osa Peninsula, sea turtles are threatened predominantly by predation and land development. However, up and coming in Costa Rica is also the popularity for ecotourism, which has resulted in a dramatic increase in sea turtle nesting on certain beaches. This growing industry provides locals with an alternative source of income in regard to the sea turtles. Where before sea turtles were hunted by locals for their eggs, shells and meat, now they are protected by them.

By Lea Fraenkl

Frontier runs a number of marine conservation projects, including volunteer projects in Costa Rica and a huge range of opportunities to volunteer in Africa.



AMPHIBIAN PROJECT PROGRESSES


Amphibians stand at the frontline of global biodiversity loss. More than one third of amphibian species are globally threatened, and over 120 species have been categorised as extinct by IUCN (International Union for the Conservation of nature) since 1980. In Costa Rica, the Frontier research team has introduced a new project investigating altitudinal migration of amphibians and reptiles. These two groups are well known for their vulnerability toward environmental stress; therefore, act as excellent indicators for environmental change.

The research programme is situated in Piro, on the southwest of the Osa Peninsula. Here, the team is situated on the perimeter of a 1700ha private forest reserve, adjacent to Playa Piro on the Pacific coastline. Whilst still in its initial stages, the project has a lot of potential to expand. Costa Rica is believed to host 5% of all the earth biodiversity. It is the home of all three orders of amphibians: caecilians, salamanders, frogs and toads. During previous years, our team in Costa Rica has been surveying amphibians’ diversity and abundance around the area, including a comparative study between biodiversity and population between swamps and leaf litter. A total of 42 species have been Identified so far, with still more being discovered. The most commonly sighted species where members of family Craugastor, and the rocket frog (Colostethus talamancae), which are listed as species of Least Concern on the IUCN Red list of endangered species, and are thought to be able to tolerate some environmental disturbance.

Frontier runs a number of wildlife conservation projects, including volunteer projects in Costa Rica and a huge range of opportunities to volunteer in Africa.