Península Valdés

Illegal hunting continues to be a threat to native wildlife in the Península Valdés region, although the level of its impact has not been systematically assessed for the World Heritage site. Poaching is mainly associated to sheep ranching and to the opening of new dirt roads that results in increased accessibility to poachers (Baldi et al., 2017). Native terrestrial mammals, especially the guanaco, fox, and puma, have been impacted by hunting and poisoning in addition to road kills (Monjeau, 2011). Hunting is fairly common throughout the Peninsula, whereas poisoning appears to be limited to selected ranches only (Nabte, 2010). The principal threat to carnivores is hunting, both retaliatory killing or to prevent predation or presumed predation on domestic animals, especially on lambs. Predators like the culpeo fox (Lycalopex culpaeus) are very rare in Península Valdés, and pumas (Puma concolor) are chased and killed when detected. Although the occasional presence of pumas does result in active persecution by ranchers allegedly to protect their sheep, the occurrence of attacks has not been documented in recent years (Baldi et al., 2017). Some rural workers kill the smaller cats, foxes and mustelids, allegedly because they prey on lambs, although the impact has not been assessed in Península Valdés. Also, a common practice to kill predators is to spread poisoned meat and eggs which kills not only carnivores but also birds of prey, armadillos and scavengers. Antún et al. (2018) modelled the spatial variation in lesser rheas abundance within Península Valdés and found that human-related factors such as the distance to ranch buildings was negatively related to their abundance. The avoidance of human dwellings by lesser rheas could be associated with activities such as hunting and egg collection for consumption (Baldi et al., 2017). From a narrow World Heritage perspective, the threat is ranked as low due to the World Heritage focus on the marine values while noting that the removal of mammalian predators from terrestrial systems results in severe and complex ecosystem changes.

Though visitor management is functional overall, increasing numbers of visitors have resulted in regular disturbance of the pinniped populations reproducing in the World Heritage site (Monjeau, 2011; World Heritage Committee, 2014). Lactating mothers of elephant seals are fasting while in the area, so they rely on blubber reserves for self-maintenance and nursing. Disturbance from human beings and dogs during this most sensitive phase can have devastating effects as energy reserves cannot be recovered. While massive tourism is controlled, tourists staying in private accommodations within the World Heritage site have unsupervised access to native pinnipeds or other fauna. Specific research to assess the impacts of this common practice in species behavior and fitness is lacking (IUCN Consultation, 2020a). Studies have shown that whale watching has some negative impacts on whale behavior elsewhere in Argentine Patagonia (Vermeulen et al., 2012). A pilot study on the effects of swim-with-whale programs at Peninsula Valdés showed short-term effects on southern right whale behavior (Lundquist et al., 2013 ). Visitors accessing intangible zones and performing recreation activities at unauthorized locations have been reported (La Nación, 2018; El Patagónico, 2018). 

Non-authorized construction of housing and temporary shacks on the beaches currently is an important conservation issue, especially in Bengoa, Larralde and Punta Gales. Given the socioeconomic characteristics of occupants, this complex management issue is not being addressed. At the same time, it is an indication of less than rigorous management and it could grow to be much more extensive in the future. This in turn constitutes a threat in terms of increased disturbance of birds colonies and pinnipeds during reproduction (Monjeau, 2011).

Regular anthropogenic fires to stimulate the growth of foraging grasses impoverish the native terrestrial ecosystems. The extent of biodiversity loss and degradation from wildfires is unknown (Monjeau, 2011). Wildfires are also common during the summer period, due to careless by visitors or started by lightning storms (IUCN Consultation, 2020e).

The steady and largely unplanned growth of the small town of Puerto Pirámides has been triggered by tourism. Impacts beyond the direct footprint on the land include poorly managed waste and increasing demand for freshwater in a semi-desert environment. The poor waste management has been linked to the explosion of the populations of kelp gull (Larus dominicanus) which feed on skin and blubber pecked from the backs of living right whales (Marón et al., 2015). While very localized, the factor is therefore ranked as a high threat.

Disturbingly high mortality rates of southern right whale were observed in and near the World Heritage site between 2005 and 2014 (Wilson et al., 2015), with a peak in 2012 (116 whales, including 113 calves, i.e. 97 percent,
Thomas et al., 2013). Average numbers of 6 deaths per year during 1971 - 2004 jumped to 75 deaths per year during 2005 – 2014 (Rowntree et al., 2013). Sironi et al. (2018) reported 774 whales were found dead on the shores of Península Valdés between 2003 and 2017. The vast majority are calves, about 90 percent being younger than three months. High mortality rates in baleen populations is very unusual (Rowntree et al., 2013). The situation has been raising major scientific and conservation interest and concern, including by the International Whaling Commission. The leading hypotheses to explain the causes of unusual high mortality proposed at experts’ workshops and following-up studies are: a decline in food availability, biotoxin exposure and infectious disease, or a combination of these factors; the role of kelp gulls attacks on whale health and density dependent processes. Results of research suggest that dead calves of Península Valdés do not show signs of malnutrition (Maron et al., 2018). Chemical contaminants were considered less likely by experts brought together at the workshops. Kelp gull attacks are considered to be a contributing factor to some whale calf deaths (Thomas et al., 2013). The hypothesis that stress from injuries in the southern right whale (predominantly due to kelp gull attacks) negatively affects their physiological homeostasis and could be a contributing factor to calf deaths in this population continues to be studied (Sironi et al., 2018; IUCN Consultation, 2020b). Density dependent mortality processes have shown to result in a redistribution of whales along the coast rather to have an effect in mortality (Sueyro et al., 2018 ). Mortality descended from 2014 onward (IUCN Consultation, 2020b). Baleen mortality in 2019 was only 10 calves, 91% lower than the average calve mortality since 2003 (Sironi and Rowntree, 2019). From 1970 to this date, population growth rate is between 5-7%. Crespo et al. (2019) conclude that current annual growth rate is 3.15%, thus lower than two or three decades before (Sironi and Rowntree, 2019; IUCN Consultation, 2020b). While it is essential to unravel the causes of previous massive mortality rates, the threat is considered to be low at the moment, considering the most recent findings.   

Most of the peninsula is privately owned and has been used for sheep ranching since the late 19th Century. Sheep grazing has caused major modifications in the steppe ecosystem and has degraded biodiversity (Blanco et al., 2017). The degree of biodiversity loss and degradation varies with grazing intensity, which is highest in the northeastern and southeastern portions of the World Heritage site. Although 80% of the land in Península Valdés is still devoted to sheep ranching, the overall stock is probably the lowest in decades (Antún and Baldi, 2020). The steppe ecosystem is less degraded as 15 years ago (IUCN Consultation 2020d). Nabte et al. (2013) documented how the grazing competition and harassment by sheep farmers poses a severe challenge to the conservation of the site's only native ungulate, the guanaco, while human-wildlife conflict affected the abundance of the puma, the terrestrial top predator. Antún et al. (2018) found that the location of ranch buildings, indicators of human presence, had a strong negative effect on lesser rheas, although their abundance increased at high sheep stocking rates. Antún and Baldi (2019) found that the location of ranch buildings had a strong positive effect on the abundance of maras (Dolichotis patagonum), presumably by providing protection against predators. However, they argue it is likely that the association could bring negative consequences for this and other species. Antún and Baldi (2020) identified that guanacos were more abundant at lower values of primary productivity and sheep stocking rates and further from inhabited ranch buildings, suggesting competition with sheep and conflict with humans. Although guanacos selected open grass-dominated habitats across sheep-free sites, fences dividing properties and paddocks played a significant role in the spatial structure of their population in Península Valdés affecting negatively the abundance of guanacos. Some landowners are currently implementing protocols of coexistence among sheep ranching and wildlife populations Despite facing threats, the number of guanacos in Península Valdés increased markedly during the last 25 years. Both the consolidation of Península Valdés as a protected area, inscribed as a World Heritage Site in 1999, and the decline of sheep ranching could have contributed to the recovery of the population of guanacos. While it can be argued that the site has primarily been inscribed in recognition of the importance for marine mammals (World Heritage Committee, 1999; World Heritage Committee, 2014), basic conservation expectations apply to the entire natural World Heritage site. Given the World Heritage focus on the marine mammals, the threat is ranked as low even though the high grazing intensity is a fundamental concern for the conservation of the remnants of the Patagonian steppe.

Seagull populations, in particular of kelp gull (Larus dominicanus) have been steadily and rapidly increasing, probably taking advantage of poor waste management practices at urban landfill and from large amounts of bycatch at sea and at fishery (Sironi et al., 2009). Kelp gulls were first observed to feed on skin and blubber of living whales when they surface (Marón et al., 2015). The percentage of living mothers and calves with gull lesions increased from an average of 2 percent in the 1970s to 99 percent in the 2000s (Marón et al., 2015). This harassment, judged as a form of parasitism by some researchers, has caused the whales to modify their behavior, surfacing less completely and for shorter periods (Argüelles et al., 2016; Sironi et al., 2009). Gull harassment appears to be affecting the overall health and survival of newborn right whale calves at Península Valdés (Thomas et al., 2015) and may be a contributing factor to the massive increase in right whale mortality rates over the last years (Marón et al., 2015; Thomas et al., 2015). The hypothesis that stress from injuries in the southern right whale (predominantly due to kelp gull attacks) negatively affects their physiological homeostasis and could be a contributing factor to calf deaths in this population continues to be studied (Sironi et al. 2018; IUCN Consultation, 2020b). The prediction is that increased severity and extent of wounds will correlate significantly and positively with increased concentration of glucocorticoids (GCs) in baleen, and GCs will be highest in calves with many wounds, lower in calves with fewer wounds and least in calves that died due to acute trauma (e.g. shipstrike) (Sironi et al., 2018 ). While attempts to cull kelp gulls so far have not resulted in effective population control, a number of options have been proposed to manage the populations (Sironi et al., 2009).

Both the southern right whale and the southern elephant seal are only seasonally present in and near the site. Their main foraging areas are located far away from the site (Jonker et al., 1998; Campagna et al., 1995, Campagna et al., 2006). Lactating mothers of both species do not feed at all when in the area. Environmental change in their wide ranges and, in the case of the elephant seals, competition with squid  fisheries are plausible reasons for concern in terms of food availability (Kovacs et al., 2012) and entangled animals are relatively common (Campagna et al., 2007). As for fisheries, it is important to distinguish the near-shore commercial fishing, which is an important economic sector in Argentine Patagonia, and largely uncontrolled fishing elsewhere in the South Atlantic. While beyond the scope of this assessment, environmental change and intense commercial fishing must be considered as factors in the future of the site.

The construction of a major commercial port in Puerto Madryn dates back to the 1970s as an integral part of the construction of the ALUAR (Aluminum Argentino) aluminum smelter. The smelter required both raw materials, primarily bauxite, and the shipping out of the aluminum products. Later on, in the 1980s, the port also became an important base of fisheries operations (fishing, factory and freezer vessels). In addition, the port serves many other transportation needs of the growing town and its hinterland (Puerto Madryn, Administración Portuaria, 2017). Every single ship to and from the port has to cross the entire Golfo Nuevo, which comes with threats in terms of disturbance, spill risks and vessel strikes (UNEP-WCMC, 2011; IUCN, 1999; Campagna et al., 1997). Currently, large-scale metalliferous mining with cyanide is prohibited in Chubut Province by the Law XVII-Nº 68. If the decision is reversed, augmented ship circulation would increase the level of this threat (IUCN Consultation, 2020c).