Threats to Lago Puelo National Park include:
• Exotic invader species
• Extractive activities
• Population increase
• Uncontrolled tourism/visitation
• Epidemiological risk
• Construction of new routes
• Impacts on the hydrography and aquatic environments
• General threats
The map below shows the most recent fires that have affected Lago Puelo National Park. The fires, which are frequent and fierce, ravage the forests and are therefore the most worrisome threat faced by the area. The size of the protected area is almost equal to the area devastated by the largest fires, such as the one of 1944, which indicates that one fire might burn down the total area of the park (1).
Map: History of the most recent fires in Lago Puelo National Park
Although scientists have been able to prove that fires were a natural occurrence in the Andean-Patagonian forests, more fires occurred after the arrival of the settlers of European origin. Many important fires have destroyed the park since the beginning of the century. The most important occurred during the 1940s and 1960s (1941, 1943, 1944, 1962, and 1963). From the 1970s, the areas affected by fires decreased.
The flora we see today is a product of past fires. The forests of some zones prone to recurrent fires or the hillsides do not yet evidence recuperation and are still covered by “notro” and “radal” shrubs, reeds, and exotic bushes.
Burnt forest in Lago Puelo (Photo © Felix Vidoz)
However, most of the area is covered with vegetation in the early stages, and the regeneration of coihue and cypress is becoming more evident. If new disturbances are prevented, those areas might fully recuperate.
The fires that occurred in the early part of the century affected some of the populations of alerces (Fitzroya cupressoides), and some areas still have singed individuals and hardly any sign of regeneration. Apparently, the lenga (N. pumilio) forests do not recuperate adequately after the fires. As a matter of fact, the areas once covered with such forests are today filled with pastures and shrubs, and the remaining lenga woods are very small and isolated (Vidoz 2000).
The conservation valoration map developed by ParksWatch shows, among the fatal flaws (red spots), patches of vegetation with a very high green index that might have not been affected by the fires maybe because the shores they live in buffered the effects of the fires. Very pristine hygrophilous forests thrive in such spots, with individuals whose age might be in the hundreds.
Socioeconomic implications of forest fires – The rudimentary economy of the early 20th Century that still thrives in the Turbio River valley (which has been a province protected area since 1994) has indirectly provoked repeated forest fires in the area shared by both parks (national and province) since 1989. The fires that have devastated this area, one of the most beautiful in the Andean-North Patagonian region, are the result of conflicts arising from the lack of employment, the advance of the forest on the pastures, disagreements among the residents (2), population increase, territory and forest claims of third parties, informal land tenure (fiscal residents), the boom of the cypress mushroom (Morchella spp.).
Cypress mushroom (Morchella spp.). The high price paid in Europe for this delicacy is one of the most prevalent causes of deliberate forest fires, because the first post-fire succession gives way to huge amounts of the mushroom (Photo © Felix Vidoz)
One of the most worrisome aspects for ParksWatch is that some residents might light fires to take revenge if the park authorities penalize them. As a matter of fact, this was the cause of many fires during the past century. There is resident in the north end of the park that lets his cows graze every night inside the park and gathers them in the morning. The park manager does not want any problems with this night intruder, because he might initiate a fire if pressured.
Cattle herding is one of the most serious problem faced by Lago Puelo National Park, second only to forest fires, although the latter do not constantly occur. Herding, on the other hand, is a permanent disturbance that results in substantial changes of the natural operation of the ecosystems. Beyond the consequences of trampling and the obliteration of the flora, cows are major scatterers of invader exotic species. As an example, park rangers recently visited an area of the Cuevas hill, a favorite place of huemules, and found cows, rather than the deer.
Cows property of neighbors grazing inside the Park, in the northern Reserve (Photo © Sofia Nazar Anchorena)
Disturbed environment invaded by sweet briar in Turbio pastures of Lago Puelo NP (Photo © Sofia Nazar Anchorena)
Cattle are brought in illegally to the park from the northern area. The Turbio, Derrumbe, and Alerzar River valleys suffer major impacts from the herding activities of the residents of the reserve. Large areas of the Turbio valley, west of the river, have been severely depleted by cattle; exotic vegetation and bare, eroded areas are all that remains. Cattle roll in the bare ground, which increases the erosive effect of the wind. Due to the magnitude of the impact (a combination of change, duration, and extension), ParksWatch believes that cattle herding is not compatible with the aims of the protected area and that there are many environmentally sustainable alternatives for economic development that can be done in smaller areas.
Invasion of exotic species
Voluntary and involuntary introduction of exotic species is considered, after the loss of habitat, the most critical threat on the biological diversity. When some species are introduced into areas where they did not exist previously, they compete with the resident species for space and food and might even feed on other species, degrade or destroy the habitat and increase the epidemiological risk.
In modern times, the lowlands surrounding the Park’s administration, which had been under intense agricultural and herding use, were almost abandoned due to new ecological prescriptions. Some European species, such as sweet briar (Rosa rubiginosa) and blackberry (Rubus ulmifolius) (3), took over the abandoned areas. A past effort to eradicate the invader species included herbicides (4), but currently the plants are removed by mechanical means from the areas of intense tourist use.
The flora succession begins with sweet briar, which have taken over every available open space thanks to the efficient dispersal of the seeds by cattle and horses. The ensuing phases, maitén (Maiten tree – Maytenus boaria) and cypress, thrive in the native forest and provide protection to cattle herds without excessive shade, replacing the role that the native bushes perform in non-altered areas. In many areas, the residents carry out permanent control of sweet briar and reserve large areas for the grasses that cattle prefer (Vidoz 2000).
Native forest with incipient invasion of exotic species in the shore of the Puelo Lake (Photo © Felix Vidoz)
Post-fire succession: invasion of exotic thorny bushes dispersed by cattle. They provide an adequate environment for the proliferation of Hantavirus-fostering rodents (Photo © Sofia Nasar Anchorena)
Several exotic herbaceous species common to the North-Patagonian region can be seen throughout the Park: Cocksfoot (Dactylis glomerata), Kentucky Bluegrass (Poa pratensis), Dandelion (Taraxacum officinale), Dallas Grass (Paspalum dilatatum) White Clover (Melitotus albus), Yellow wood sorrel (Oxalis corniculata), and others, which are generally associated with areas disturbed by cattle, fires, or tourist use (5). The fact that these species are not plentiful in pristine sites, which proves the statement above, indicates that they can be kept under control if the activity that causes them is eradicated. Sweet briar and blackberry shrubs are quite abundant. Blackberry shrubs are very exuberant and impede the growth of the native flora.
The Spanish Broom (Spartium junceum) is another very aggressive and high-impact invader that, like blackberry, grows thick shrubs under which the native vegetation cannot mature. After the fire of 2002 in the Recreational Area, retama took over the areas previously covered by sweet briar and the species is today uncontrolled and presents a short-term problem. There are also several exotic trees generally associated to old and current settlements. There are several poplar and pine species, as well as other exotic evergreens, and a handful of fruit trees. Poplars are taking over the area surrounding the shore and the Turbio River sector, where they compete with cypress trees. Oregon and Ensign thrive in the area, but the areas covered by them are still negligible.
Native pine species are taking over the native flora of the northeast boundary of the park; there are commercial plantations in the surrounding areas. The wind is greatly contributing to the worrisome dispersal of Pinus contorta, and some individuals reach beyond the timberline. Maple trees are also disseminating rapidly and there are some important nuclear patches close to the dock and the administration. Throughout the delta of the Azul River, Salix fragilis is causing severe conservation problems and is depleting important sites of recreational value and interfering with the hydrological and basin balance of the river, which might suffer from the invasion of the trees and might prefer flowing into the Recreational Area, where there are several tourist services. This species is rapidly dispersing throughout the few beaches of the lake and is overtaking the areas for the visitor’s use while simultaneously providing shade. Many removal methods have been essayed, with mechanical means (Vidoz 2000).
Exotic trees (mainly poplars and willows) have overtaken the landscape of the North area of the Lago Puelo NP (Photo © modified from the Lago Puelo NP Administration / Felix Vidoz)
The most prevalent vertebrates are wild boar, mink, and European hare, and the Californian quail, since 2000. Rainbow and River Trout have taken over the bodies of water and their management is difficult, because they influence changes in affected communities.
Salmons feed on native fish and other components of the aquatic fauna, and present a potential threat because they feed on amphibian larvae and adults, which impedes that these aquatic animals re-populate the areas from they have disappeared due to depredation or other causes, and might also isolate the many different amphibian populations of the sub-basins if the main courses are threatened. Salmons have a high economic value and are of regional importance, aspects that must be taken into account when defining management strategies (Vidoz 2000).
The residents illegally hunt wild boar, and hunting dogs might kill pudú, foxes, ferrets, and huemules. There is no information available about the impact of wild boar, but their effects on the flora and the ground are very evident in some areas.
It has become evident, in several places of the Patagonian region, that aquatic bird populations dwindle when minks invade the water bodies. The latter also have an effect on otters (Myocastor coipus). There are no systematic data yet, but it seems that the autoctonous fauna has been able to recuperate a few years after minks have invaded a body of water.
There is evidence of populations of Red deer (Cervus elaphus) in an area very close to the park, so it is highly that these animals might inhabit the Park in the short or medium term.
An invasion of German yellowjacket wasps (Vespula germanica) causes problems in the main recreational center of the park, especially between mid-February and March. Large swarms jeopardize the bathing area and disturb the visitors. The effects of the wasps on the native communities have not been studies, but they have been seen feeding on native insects.
Nature resource use
Park rangers estimate that 50% of the regular low-impact illegal entries to the park are controlled, but Park Management believes that only a handful of sporadic entries are of importance.
In late September, the pollen clouds from cypresses announce the eclosion of mushrooms of the Morchella genus, which are highly coveted by European gourmands and can therefore be sold at very attractive prices, whether dried or fresh. The spring after the cypress forests have burned down, for one time only, there is an exceptional eclosion of these mushrooms, which is the cause of many intentional fires. After the edible mushrooms are reaped, the mycelium cannot produce any more, so the extraction is final.
The Leatherleaf fern (Ruhmora or Polystichum adiantiformis), which thrives at half shade in these forests, has been commercially exploited since 1995 in the areas surrounding the Park and are sold to flower shops in the big cities. This has caused a dramatic decrease of the species and very intense illegal harvesting in the Park boundaries, which has forced the park rangers to constantly patrol the area to hamper illegal harvesters (information from the Patagonia Technical Delegation) (6).
Ornamental ferns in Lago Puelo NP (Photo © Sofia Nazar Anchorena)
Just recently, an inordinate harvest of “murta” (Chilean Guava – Ugni molinae) has been noticed. These fruits mature in late summer and are used to produce sweets and liquors that are sold in regional fairs. This fruit must be managed, because of the high demand among the resident (Vidoz 2000).
Another recent problem is that cypresses, both dry and green, have been cut down to produce eaves in situ. The eaves are of higher added value than raw wood and are easily transported. The main pressure has been noticed in the Desemboque area in the last year.
ParksWatch is concerned about the demographic increase trend of the families that reside in the Turbio area. The residents must be offered alternative economic alternatives, which is an objective compatible with the environmentally sustainable economic development of the National Reserve areas. Some park rangers interviewed, however, believe that the improvement of the quality of life of the residents will only translate in more residents, because the family members move in with them to enjoy the improvements and will, in turn, deplete the natural resources even further.
Without a doubt, tourism is the best ally of the national parks, more than any other economic development activity. This is because tourism permits to satisfy the economic demands without taking up too much space, in a timely manner, and producing low and medium intensity disturbances that are generally reversible. After the devaluation of the Argentine peso, there has been an explosion of foreign and national tourism. Ecotourism and adventure tourism are the most sought after activities in the country.
National parks are one of the most important places where the activities can take place. This is an important opportunity for the federal system of protected areas. However, the sector is growing too fast and no national guidelines have been issued for the purpose. National Parks has very complete rules regarding tourism and the guides that operate in the protected areas must do extensive tests, but the number of park rangers might soon be too few to control and monitor the activities.
The main problem results from waste management. The beaches used by the tourists are strewn with garbage, which is picked up by the rangers (not in their job description!), young volunteers, and maintenance personnel. Although signs have been posted, the amount of garbage left by visitors during peak periods is too much for the Park administration to handle. The major impact of this action is indirect: since garbage is the most obvious disturbance and evident to non-environmentally aware visitors, most of the complaints to park rangers and the park’s administration have to do with the unkempt grounds. The complaints have resulted in 5 of the 6 park rangers of the Lago Puelo NP devoting 90% of their time to control a low conservation value public bathing spot and therefore not caring for more critical areas.
Tourists usually carve the barks of the arrayán trees (Myrceugenella apiculata) of the Bosque de las Sombras trail. Most carve names and dates (E.g., Tito, 12/01/2004) perhaps wishing to preserve their “art” for eternity. Immortality, alas, deserves more merit and talent.
Bonfires are highly controlled in the camping areas. However, ParksWatch witnessed one of the many events with which the park rangers have to deal with frequently: a camper was brandishing a lit branch close to his tent (7).
More visitors mean more vehicles. In 2004, a car hit a pudú inside the park. After the animal recovered, a veterinarian who collaborates with the National park liberated it inside the strict Reserve. This type of accidents might occur more frequently if the traffic increases.
Cypress disease: Some cypress trees of the Turbio River area exhibit signs of a fungus infection called “cypress disease” that makes the leaves fall and eventually kills of the tree.
Hantavirus: The long-tailed pygmy rice rat (Oligoryzomys longicaudatus) is the principal Hantavirus host. In 1997, there was a population boom of this rodent in the Turbio area, mostly due to the proliferation of sweet briar, which are this species’ favorite habitat and food. Neither the trails that cross the natural forests of Lago Puelo NP nor the open and well-aired spaces are prone to any epidemiological risk.
The most troublesome project inside the reserve is the opening of an international highway that will end in Chile.
Los Hitos sector of Lago Puelo NP. The narrow space to the left of the picture is the Chilean boundary, where the Chilean highway ends. One of the project’s alternatives strives to continue the road into Argentina, through National Reserve forests that can be seen in the lakeshore (Modified photo by the Lago Puelo NP Administration /Felix Vidoz)
The opening of a controlled frontier post between Argentina and Chile is of major importance for the development and integration of the Los Lagos region. The post would increase Chilean visitation to Lago Puelo NP Regardless of the obvious benefits, the highway project proposes a direct environmental impact and collateral impacts that are not in synch with the conservation objectives of the protected area.
The conservation value map shows that the highway would interfere with areas with moderate to high conservation values, including some areas of very high conservation value and a patch that is considered a fatal flaw.
Impact on hydrography and aquatic environments
In general terms, the deforestation caused by fires and overherding has a major impact upon the natural hydrography of the Puelo system, because it increases the drainage speed which brings about an excessive sedimentation of eroded materials and fosters uncontrolled flow (8). The lack of vegetation in the areas surrounding the Park, which are almost totally deforested, causes uncontrolled flow and the forests don’t retain any water. For this reason, heavy rainfall elevates the level of the Puelo Lake waters. The lake is growing more dependent on the melting of ice at the headwaters of the Turbio river basin, which will cause that the level of the water and stratification change be more evident in the future.
Occasional floods after heavy rains and the overflow of the lake destroy shore infrastructure (dock, information booth, tables and chairs.)
Overflow of Puelo Lake. The picture shows how the overflow of the lake can flood the entire north area and can affect the Park Administration building (Modified photo by the Administration of Lago Puelo NP / Felix Vidoz)
Pollution of aquatic environments
Puelo Lake is located mid-basin, downstream from water bodies and courses that are outside the protected areas. There are relatively important human settlements in the shore of the lake, the populations of which have grown in the last few years. The lake drains into a basin that has a growing population of 22,350 residents and that is visited by more than 20,000 tourists during the summer. Regardless of the quick renewal of the water, there is evidence of eutrophication, which brought about the need to build the sewage purifying plant in El Bolsón. The clarity of the water is gradual from the headwaters of the Turbio River to the delta, with an average value of 9 meters.
The Turbio, Epuyén, and Azul Rivers are the most important affluents. The National Parks does not have authority on any of the three. An important sub-basin that belongs to the Province Park and the Turbio multiple use reserve drains into the Turbio River, where regulated productive activities are permitted. The Epuyén River drains the Epuyén Lake into the Puelo Lake; it receives the sewage of the shore villages of Epuyén and Hoyo (previously treated in the El Salamín lagoon.) The important agricultural and cattle activities in the valley cause fertilizer and agrochemical contamination. Another affluent of the Azul River is the Quemquemtreu, which carries the sewage waters from El Bolson. Those waters only receive first-phase treatment.
The preliminary studies performed to date have not discovered any pollution in the lake. Lake Puelo is the final link of the sub-basin, which makes it very vulnerable (Vidoz 2000). However, it has been confirmed that the Azul River is contaminated.
In the future, as the upriver population grows, the contamination of the lake and rivers might become a problem, as well as the changes in land use and the loss of the buffer areas around the National Park due to tourist development and the growth of the surrounding populations. ParksWatch is concerned about a small land plots project initiated by the Municipality of Lago Puelo. This project might bring about an inordinate growth of the population, which will translate into heavier pressure upon the hydric system of the Lago Puelo National Park.
General threats, integrated analysis
The most serious threats to the natural heritage of the park are forest fires and cattle herding, because they alter the environment during long periods. In third place, invader exotic flora is slowly creeping upon the park and has invaded former cattle grazing areas. The intrusive sweet briar shrubs have disseminated throughout several areas of the Park and have overtaken former cattle grazing areas, which increases the epidemiological risk of Hantavirus. Blackberries, willows, acacia, Spanish broom, oak, and several fruit trees and herbaceous plants have also been introduced. The dissemination of exotic evergreens inside the forest is worrisome because they have overtaken the native forest and former pristine sites. Minks, wild boars, and salmons jeopardize the native biological diversity. The increase of legal and illegal population in the Turbio area hinders the sustainability objectives of the National Reserve. The Puelo basin relies mostly on the melting of the ice in the headwaters of the Turbio River, which might unbalance the hydrological system if it becomes completely dependent on rainfall. Waters flow uncontrolled throughout the park because many areas are severely deforested. For this reason, heavy rainfall might dramatically increase the level of Lake Puelo. The park faces other threats: hydric pollution of the Puelo Lake waters by the Azul River, that carries sewage from the Lago Puelo village and surrounding towns; the urbanization of small parcels, an initiative of the Lago Puelo municipality, might increase this impact; the opening of an international highway running from the protected area of Paso Puelo in Argentina to Los Hitos, Chile; the weak law enforcement by the very few park rangers, inadequate funding, and garbage disposal in the beach area.
The global threat map (see map below) shows that all of the National Reserve is under moderate and wide threats. The map does not include fires because they are treated differently (because they are occasional and not permanent). The fires are considered a high-probability threat, especially during the dry months of summer because the combustibility of the forest increases, endangering the total area of the National Park.
Layers of threats faced by Lago Puelo NP This image is the result of the overlaying the pixels that represent the magnitude values of each theme map. This map does not include forest fires because there is a specific map for this subject.
(1) A meta-analysis of the fires in the protected areas of the world concluded that the ideal relationship between a protected habitat and its FIRE regime is from 10 to 1. When the ratio is lower, recuperation is partial and fragmented (Meefe and Carroll, 1994). In other words, a protected forest should ideally be 10 times larger than the largest historical fire-ravaged area.
(2) There is evidence that the fire that destroyed 10,000 hectares in 2002 started in the Turbio Provincial Reserve after a heated and long dispute between neighbors (one of them burned down the other’s plot.) These disagreements are hard to assuage and will probable keep causing more environmental problems in the future. Increased conservation actions might also cause further upheaval among the residents.
(3) Locally called “murra”(Rubus ulmifolius), which found the ideal conditions for rapid proliferation. By 1980 they were already considered noxious weeds.
(4) The failure of these experiments and time permitted the park rangers to notice that some weeds protected the seedlings of autochthonous trees (especially from the actions of the cattle brought in from outside the Park) and became tutors of future maintenes and cypress bushes.
(5) It would be beneficial to explore Eduardo Rapoport’s proposal about edible weeds, which shows the surprising amount and quality of food available in one hectare.
(6) The illegal extraction of ferns increases when the Chubut province authorizes harvesting for ornamental purposes. The harvests are intense and unsustainable in the countryside and the species are quickly disappearing; illegal harvests are frequently the culprits.
(7) It was almost midnight, on a Sunday, when a park ranger suddenly appeared and suggested to the camper, “if you want to play with fire, do it somewhere else.” The camper apologized and said that he was using the branch to find his way in the darkness. This example shows that our protected areas are in jeopardy if the public is not environmentally aware. Apparently, flashlights and common sense are not abundant in the region.
(8) This is very evident in the western shore of the lake, which was very affected by the 1987 fire.