The Road Lesser Traveled: A Map to Rheabilitation and Conservation By Kenna Mokobi

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1 The Road Lesser Traveled: A Map to Rheabilitation and Conservation By Kenna Mokobi Sophomore College: Parks and Peoples with Professor Bill Durham 16th October 2016 Stanford University Picture 1: A lesser rhea travelling on road near Torres del P aine mountains, by Author

2 Abstract The lesser rhea is an endangered ratite species that hails from the steppe of Patagonia. The rheas along with the guanacos are two animals that have historically dominated the steppe, and have the largest biomass in the steppe. Centuries ago rheas ran in flocks in the million, but after hunting and egg harvesting throughout the years, they have had their numbers reduced significantly and in some areas are considered wiped out. The rhea has been categorized as near threatened by the IUCN Red List, and has been for over 15 years. The population has been steadily decreasing and population of the lesser rhea outside of captivity is still unknown. Despite conservation efforts and changes in policy the population continues to decrease. This paper is a paper based research investigation on the different circumstances that may contribute to the reduction of the Rhea species. I will explore two hypothesis, both focused in the Rhea s habitats and nesting patterns to unwrap the mystery of the declining lesser Rhea. Hypothesis 1 states: Lesser rhea habitats are fragmented by farms and other man made structures. Hypothesis 2 states: Lesser rhea nesting sites are more exposed to hunting, egg harvesting and overgrazing. The paper will conclude on a discussion on current conservation methods to save the Rhea.

3 Introduction Also commonly known as Darwin s Rhea, the lesser rhea is a ratite closely related to the Greater rhea. The lesser Rhea inhabits the steppe of Patagonia, south of the Rio Negro in Argentina while the greater Rhea occupies the pampas to the north of the Rio Negro. These closely related species have played a large part in the regions culture, history and ecosystem. To locals the Rhea is an important cultural factor, especially in the steppe. On a trip to the region of Patagonia, a local tour guide named Alexander explained how in their mythology the Rhea ran down a stretch of

4 road through the night, and it ran so far it got to the sky and left it s footprint. This footprint is the Southern cross that is a key navigational constellation in the southern hemisphere. Symbols of the footprint are found in many parts of clothing and decorations from the South of Argentina. The Rhea not only has cultural importance, but also in its own way contributed to the scientific community. The rhea inspired some of Darwin s early thinking on the theory of evolution. It gets its name from his discovery of its differences from the greater Rhea on his adventures on the Beagle II. These differences helped kindle Darwin s thoughts on differences in animals as a result of the space they occupy. The rhea s population has been declining for years. Hunted for its feathers, it has gone through epochs of mass rhea killing. The lesser rhea have also had to face the creation of estancia s which have taken up acres of land to help raise invasive sheep. The sheep have caused problems for the ecosystem;their overgrazing causes desertification in the area. In recent years, farms have divested from wool and invested in rhea farms but even these tame rheas homogenous rhea do not aid in the species survival. The lesser rhea faces many issues, that could lead to loss of its wild population.

Research question- What are the issues stopping rheas from repopulating? Hypothesis 1 - Lesser Rhea habitats are fragmented by farms and other man made structures.

5 Research question- What are the issues stopping rheas from repopulating? Hypothesis 1 - Lesser Rhea habitats are fragmented by farms and other man made structures. In order to investigate this hypothesis, the habitats of the Lesser Rhea must be better understood. Through the research of Laura M. Bellis, we can categorize the lesser rhea s habitats into four types based of vegetation and coverage: Steppe, shrubland, shrub-steppe and wetlands, locally known as mallines (Bellis et al. 2005). Picture Illustrating the typical steppe of Patagonia with 2 hares roaming the area. B y Author

6 These four types of habitats vary in use, but are the main feeding grounds for the lesser Rhea. Steppe is the typical landscape of the Patagonia region; Steppe is dominated by tussock grass. Shrubland has medium sized to tall shrub, (about 1m). Shrub-steppe has a combination of low shrubs (<0.8m) and tussock grass. Steppe, shrubland and shrub-steppe have vegetation that creates ground cover that varies from about 24-29%. Mallines are the most unique of these habitats as they differ vastly from the classic steppe of Patagonia; Mallines are wetlands mainly composed of cyperaceous species and different grass shrubs. Mallines have the highest ground coverage (95.73%) and nil shrub density. The study found that rheas mainly use shrub-steppe and steppe as feeding grounds, but use varies throughout the year as a result of its breeding season. The lesser rhea has adapted to the arid environment by selecting breeding sites that balance profitability of feeding with cost of predation (Bellis et al. 2005). The lesser rhea has adapted by being able to move over larger distances, while the greater rhea has smaller habitats. A different study conducted by Bellis et al. found that lesser Rhea occupied larger areas due to the differences in availability of food; see table 1 on next page. By releasing both greater and less rhea that were grown in

incubation following the World Conservation Union guidelines for reintroduction in the regions of El Refugio, Las Dos Hermanas, El Remiendo and Loma Blanca, the researchers were able to find the

7 incubation following the World Conservation Union guidelines for reintroduction in the regions of El Refugio, Las Dos Hermanas, El Remiendo and Loma Blanca, the researchers were able to find the distances covered and Table 1: illustrating different habitat sizes for Greater and lesser Rhea areas the two species occupied. During the trip, tour guide Alexander explained rhea birds are able to move through the six wire fences around farms. Human presence due to agricultural activities (sowing, plowing, harvesting, livestock movements, sheepshearing, etc.) in each of the study areas does not appear to influence the spacing behavior of lesser and greater rheas. (Bellis et al. 2003). Thus

8 the hypothesis that man-made structures are creating fragmented habitats is not supported. Hypothesis 2 - Rhea nesting sites are more exposed to hunting, egg harvesting and overgrazing. As stated earlier, Darwin s Rhea has the most success in nesting among ground nesting birds (Barri et al. 2008). Barri et al found the lesser rhea over a course of 2 reproductive seasons had 71% and 78% success rate. Despite a higher success rate at nesting, rhea that reach their juvenile years are the same in number as other ratites, like the greater rhea. This hypothesis will investigate the role that mallines (nesting sites) play in rhea conservation, and if they are more exposed to hunting and egg harvesting. Post hatching, rhea males prefer to feed at mallines while they care for their chicks. Mallines offer a higher concentration of food. Barri et al Found that vegetation cover on average was 14.8% higher at nesting sites than at randomly selected feeding areas. Barri et al also speculate hat

9 the lesser rhea may use the higher vegetation cover as method of protection for their nests from predators. Their selective nesting habits may contribute to the success of rhea protection, and this also emphasizes the key role they play in conservation of the lesser rhea. As locals of the Patagonia steppe, lesser rhea have to move further for their food than most ratites, which is why the males invest in taking care of their chicks after hatching. When comparing the size of the habitats, it was seen lesser rhea could cover 4 times the area covered by Greater Rhea in search of food. The most telling factor for where a nest was selected was its proximity to the mallines. Mallines occupy the smallest area of the four habitat types in the Patagonia region, but boast the highest vegetation cover. These areas are pivotal in the reproductive process of lesser rheas. In a study conducted by Barri et al. 2009, researchers found 35 nests and followed the success of the each nest they observed within an area of 114km^2. 23 nests were successful with 12 being unsuccessful. Of the unsuccessful nests, they found that male rhea had deserted 10 out of 12 unsuccessful nests. Male rheas play a pivotal role in caring for the chicks, once a nest is abandoned success of nesting reduces significantly. Only 1 of the 12 nests was destroyed by a predator, which shows the selectiveness in nesting may contribute to their success. Anthropogenic disturbance caused

10 75% of all nest failures (Barri et al. 2008). 7 nests were abandoned as ranch workers came into contact with Rheas and one was harvested. 3 nests were deserted for reasons unknown to the researchers. These results show humans are the biggest factor in desertion of nests. Figure one shows the number of eggs in deserted nests is significantly lower than in successful nests because the nests were deserted in the early stages of the nesting periods, most commonly as a result of human disturbance. This figure illustrates the potential in population growth if less nests were abandoned. In an earlier study, Barri et al. 2007, found 3 ranches that varied in hunting and egg harvesting. In ranch one and two there Fig 1: Average maximum number of eggs per nest were no significant (white bars) in 23 successful and ten deserted Lesser Rhea nests from both reproductive seasons, and differences in the average number of eggs hatched(grey bar) in successful nests. metrics they used for success, but ranch 3 which had high hunting and egg harvesting had no nests recorder over both periods and significantly lower

vegetation in shrub and grass, means there is less overlap in

11 rhea populations. Table 2(next page) shows data from ranch 1 and 2 as ranch 3 has no recordable data. The study found that the lesser rhea s ability to eat a variety of vegetation in shrub and grass, means there is less overlap in competition with other species so it is not as affected by overgrazing (Barri et al. 2007). He later finds there is potential harm in overgrazing; mallines are used by farmers to feed their livestock (Barri et al. 2009). The data supports the hypothesis that Rhea nesting sites are more exposed to hunting, egg harvesting and overgrazing.

12 Discussion Conservation efforts for the lesser rhea should focus on the protection of the malline sites. Studies conducted have concluded that activity of hunting, egg harvesting and even ranching have serious effects on the reproductive success of the lesser rhea. Mallines are limited in the region, and cooperation from farmers will be pivotal in restoring the lesser rhea. In conducting this research, the relationship between farmers and researchers was intriguing. Almost every researcher used a ranch as their base, and some worked on ranches to incubate and raise lesser rhea to be released for their studies. On the field, tour guides would describe the rhea as being useful to the greater ecosystem and thus could be beneficial to farmers to restore the rhea. Conservacion Patagonica has made strides in Chile by starting a breeding program in 2015 at Nandu Park. The group works with volunteers and park officers who find orphaned eggs, incubate them, hatch them and release grown Rhea into the wild. If efforts were made to have even farmers donate orphaned eggs, the reproductive success of the lesser rhea would be boosted, as the impact of human activity will be reduced. The rhea may yet decorate the steppe of Patagonia once again.

13 Acknowledgements Firstly, I want to thank all the alumni and Joey Durham who came on this trip with us. You made this a journey unlike any other, and were able to rekindle that excitement to learn that we share across generations at Stanford. It was a pleasure and an inspiration to share the trip with these eager minds. I d like to thank the alumni center and all the coordinators who made this an amazing, well-planned and fun trip. I d like to thank all my peers for simply being amazing, curious, driven and inspirational students. Lastly I thank Professor Bill Durham, and ours SCAs Shannon Swanson and Elana Springer for all the help guidance throughout this course. They made this an amazing trip, and an unforgettable learning experience.

14 References Glatz, P. C., Christine Lunam, and Irek Malecki. The Welfare of Farmed Ratites. Berlin: Springer, Print. Bellis, Laura M., Monica B. Martella, Joaquin L. Navarro, and Pablo E. Vignolo. "Home Range of Greater and Lesser Rhea in Argentina : Relevance to Conservation." Biodiversity and Conservation (2004): Springer.com. Web. Barri, Fernando R., Mónica B. Martella, and Joaquín L. Navarro. "Nest-site Habitat Selection by Lesser Rheas (Rhea Pennata Pennata) in Northwestern Patagonia, Argentina." Journal of Ornithology (2009): Web. Barri, Fernando R., Mónica B. Martella, and Joaquín L. Navarro. "Effects of Hunting, Egg Harvest and Livestock Grazing Intensities on Density and Reproductive Success of Lesser Rhea Rhea Pennata Pennata in Patagonia: Implications for Conservation." Oryx (2008): 607. Web. Bellis, Laura M., Joaquín L. Navarro, P. E. Vignolo, and Mónica B. Martella. "Habitat Preferences of Lesser Rheas in Argentine Patagonia." Biodiversity and Conservation 15.9 (2005): Web. Barri, Fernando R., Monica B. Martella, and Joaquín L. Navarro. "Reproductive Success of Wild Lesser Rheas (Pterocnemia -Rhea- Pennata Pennata) in North-western Patagonia, Argentina." Journal of Ornithology (2008): Web.

Species Fact Sheets. Order: Struthioniformes Family: Rheidae Scientific Name: Rhea pennata Common Name: Lesser Rhea

Species Fact Sheets. Order: Struthioniformes Family: Rheidae Scientific Name: Rhea pennata Common Name: Lesser Rhea Order: Struthioniformes Family: Rheidae Scientific Name: Rhea pennata Common Name: Lesser Rhea AZA Management: Green Yellow Red X None Photo (Male) with juvenile chicks: The female is generally duller