Finished on May 31/2021
Abstract
Herds of hippopotamus are threatening ecological integrity at the Colombian’ Magdalena River Basin (MRB). Management actions have been implemented for reducing reproduction rate amongst the individuals that invaded wilderness in the novel environment at the Andean; however, efforts have been unsuccessful for controlling the invasion. Thus, negative human-hippos’ interactions are increasing, hippos are causing economic losses, and are threatening biodiversity conservation and landscape integrity.
This article reviews the ongoing ecological threat to the Colombian neotropics caused by wild populations of hippopotamuses, introduced in the MRB approximately 40 years ago. The review starts with a revision of the invasion´s history, highlights the uncertainties about the individuals imported, and the animals that scaped and are currently living and reproducing in the wilderness. Afterwards, the species ecology is described and addressed for elaborating thoughtful insight for understanding drivers of ecological change and threats to public health. Then, the novel ecosystem is described for considering impacts on the biotic and abiotic resources, and finally, considerations on actions to implement for the invasion management are discussed.
Keywords
Alien species. Ecosystem engineer. Megaherbivore. Soil fauna. Magdalena River Basin. Human-Wildlife conflicts.
Resumen
Hatos de hipopótamos están amenazando la integridad ecológica de la cuenca del río Magdalena en Colombia. Aunque se han implementado acciones de manejo para disminuir la tasa de reproducción entre los individuos que escaparon al estado silvestre en los Andes; los esfuerzos para controlar la invasión han sido poco exitosos. Como resultado del aumento en la población de hipopótamos, las interacciones negativas entre humanos e hipopótamos han aumentado; además, están causando pérdidas económicas y están amenazando la conservación de la biodiversidad local y la integridad del ecosistema.
Este artículo hace una revisión de la actual amenaza ecológica que enfrenta el neotrópico colombiano, causada por la introducción de hipopótamos hace más de 40 años. La revisión inicia con la historia de la invasión, resaltando la poca certeza que se tiene con relación a la cantidad de individuos importados y los que actualmente se encuentran reproduciendo libremente en la cuenca del Magdalena. Posteriormente se hace una revisión sobre las características ecológicas de la especie, destacando aquellas que promueven el cambio ecológico y ponen en riesgo la integridad biológica y la salud pública dentro de la cuenca. Luego, se describe la cuenca del Magdalena para entender los posibles impactos en los recursos bióticos y abióticos; y finalmente se discuten alternativas en el manejo de la invasión.
Palabras clave
Especie invasora. Ingenieros del ecosistema. Mega herbívoro. Edafofauna. Cuenca del Magdalena. Conflictos Humanos y fauna silvestre
Introduction
Hippopotamuses are large mammals that occur in sub-Saharan Africa; currently, there are two living species, the pigmy hippopotamus with 2 subspecies, and the common hippopotamus, which has 5 subspecies (Ed. Oliver, 1993). However, some hippopotamus individuals were imported to Colombia for a private collection of exotic animals; the hippos found a pleasant environment in the neotropics and successfully reproduced; an uncertain number of animals scaped from the enclosure and continued reproducing and spreading over the region. In 2012 the species was acknowledged as the largest invasive species in the world by the Invasive Species Specialist Group from International Union for Conservation of Nature (IUCN).
The species has an amphibious behavior, hippopotamuses graze on land at night, moving several kilometers during the night if required; and spend daytime submerged in water for maintaining the skin moist. Furthermore, described as an ecosystem engineer, given the enormous size, and feeding habits, hippopotamuses’ behavior impacts ecological integrity, threatens terrestrial and freshwater diversity, and is already causing economic loses to communities. At the MRB, ecological and climatic conditions are favorable for satisfying the species requirements, wide ranges of grass species and constant water flow, furthermore, conflicts are to increase if wild population continues to growth and spread over the region.
History of wild hippos in Colombia.
In the 1980’s hippopotamus individuals were brought into Colombia, yet there is lack of certain information of how many animals were imported nor when the transport was made. Whereas the CITES trade Database registers that, between 1975 and 1993, there was only one import in 1982 of 3 individuals of hippopotamus pygmy species, from the United States to Colombia (CITES Trade Database); there are many unofficial histories about how such animals were introduced. According to Valderrama (2012), 6 individuals of common hippopotamus were brought in 1981, yet others says it was 4 individuals (Subalusky, et al., 2019), Monsalve (2018) states that the import consisted of 2 to 6 individuals in 1985. Once in Colombia, the animals were kept in a private collection at the MRB; between the Oriental and Western Andean Cordillera at Doradal Municipality, Antioquia Department. Then, the hippopotamuses successfully reproduced in captivity. In 1993 the private zoo was abandoned, yet the animals survived and continued reproducing. The lack of management to the property, in addition to intruders breaking in the area facilitated some individuals to scaped into the wild; yet it is also uncertain how many scaped (Valerrama Vasquez, 2012; Monsalve Buriticá & Ramírez Guerra, 2018).
In 2006, the property became a tourist complex with an estimated number of 16 hippos remining within (Subalusky, et al., 2019), nonetheless the population continued growing and spreading across the region. Observation of hippopotamus nearby rural populations are increaing, they have been seen up to 150 km away from the original enclosure (Shurin, y otros, 2020); although the estimated current distribution within the MRB is about 2000 km2, it could extend to 13500 km2 (Castelblanco Martinez, y otros, 2021). Furthermore, reports of conflictive interactions are rising; on May 11, 2020, occurred the first non-lethal attack from a hippopotamus to a human, in Puerto Triunfo Municipality, Antioquia Department.
Nevertheless, management actions for controlling the population growth have been stablished; 4 individuals have been sterilized and 1 more was culled; however, efforts implemented are unsuccessful for controlling the rising hippopotamus’ birth rate in the wild (Subalusky, et al., 2019). Although conservative models predicts that the ecosystem’s carrying capacity will be reached between 2040 and 2050 with an estimated of 500 individuals (Castelblanco Martinez, y otros, 2021); others predicts a steady population growth rate between 5 % to 11 %, thus, by 2050
there could be between 400 to 5000 individuals of hippopotamus in Colombia (Subalusky, et al., 2019). Nonetheless, in favorable environmental conditions population growth rate could rise to 18 % (Moneron & Drinkwater, 2021). Thus, nonnative herds of one of the third largest mammal in the world are self-sustaining, growing and spreading across the geographical range at the MRB, causing ecological threat to the ecosystem end producing economic harm (Lockwood, Hoopes, & Marchetti, 2007; Valerrama Vasquez, 2012).
Family Hippopotamidae
Hippopotamuses belong to the biological Family Hippopotamidae, which is represented by two living species, Hippopotamus amphibious also known as common hippo, kiboko or mvuvu; and the smaller pygmy hippopotamus, named Hexaprotodon liberiensis (CITES, 1994; Lewison & Pluháček, 2017). Hippos evolved from a common ancestor with marine mammals such as whales, the closest living relative; and the cleft-footed mammals such as cows, goats, and camels (Boisserie, Fisher, Lihoreau, & Weston, 2011); in fact, the Latin translation from the name stands for “hippo” meaning horse, and “potamus” which means river; hence, hippopotamuses are known as the river horses. The name adequately describes the species behavior, as they spend the daylight hours submerged in waterflows or ponds, and during the night they emerge for grazing.
Historical records of hippos’ fossils from Pliocene and Pleistocene conclude that, they were numerous and diverse; the Family Hippopotamidae was distributed in Europe, Asia, Africa, and Madagascar (Ed. Oliver, 1993; Boisserie, 2005). Three thousand years ago, the hippopotamuses were common throughout the Nile Delta to South Africa, the original species’ geographic rage (Lewison & Pluháček, 2017). Humans have long used hippos for different purposes; ancient Egyptians kept them in private zoos, likewise, animal parts are used by African Indigenous Peoples in the African traditional medicine, and for cultural and religious representations (Subalusky, et al., 2019). However, after the 1800’s the species went regionally extinct in northern Africa, and populations begun to decline (CITES, 1994), although, they are still well represented across sub-Saharan Africa (Lewison & Pluháček, 2017). Estimations of the global population is of 145000 individuals, unevenly distributed within the lakes, rivers and wetlands across different regions and protected areas in Africa; whereas the southern and eastern region holds the largest population, the western side of the continent holds about 5 % of the hippopotamus global population. (Lewison & Pluháček, 2017).
Hippopotamuses developed evolutive adaptations for the amphibious lifestyle. For the aquatic life, hippopotamuses built breathing adaptations, for example can last up to 19 minutes holding their breath, and autonomously emerge for breathing while sleeping (Ed. Oliver, 1993; Flindt, 2006). While diving, muscular valves are adapted for closing the ears and nostrils (Walzer & Stalder, 2015). The skin has thin epidermis, and thick dermis with heavy fat tissue; lacks sebaceous gland and retain few hairs. However, the species secretes oily red mucous called “blood sweat” that provides them with antibiotic and sunscreen activity (Saikawa, Hashimoto, & Nakata, 2004; Walzer & Stalder, 2015).
Likewise, for the terrestrial lifestyle they are admirably adapted, hippos are the third largest mammal on earth after elephants and rhinos; they can weigh up to 3200 kg, are 4,2 m large, and can attain 1,6 m high. Nonetheless, despite hippos’ size, strength, and great bulk, they can reach formidable speed on the ground, the maximum speed is 48 km/h (Flindt, 2006). When emerge at night for grazing, hippos can move between 10 to 12 km to find feeding crops; additionally; hippos are very resistant, they have been found in altitudes higher than 2000 m.a.s.l. in the native range (CITES, 1994; Walzer & Stalder, 2015).
Hippos are described as mega-herbivores, because of their great size and their feeding behavior; they are exclusively herbivores, yet they rely entirely upon terrestrial plants. Hippos are pseudo ruminant; while they have a four-chambered stomach, they do not ruminate (Walzer & Stalder, 2015). Hippos’ jawbone is equipped with 12 teeth ivory made, 8 incisors and 4 canines weighing in total approximately 5,25 kg (UNEP-WCMC, 2020; Moneron & Drinkwater, 2021). Daily food intake range between 30 kg to 45 kg of biomass; in a year, each hippopotamus can consume up to 12 ton of forage, including on their diet more than 44 species of grasses from their native range, specially from Poaceae, Polygonaceae and Cyperaceae families (Dibloni Ollo, Soulama, Ouedraogo, & Guenda, 2012; Mekonen & Hailemariam, 2016). Furthermore, hippos’ feeding behavior follows the central place foraging strategy, in which according to the vegetation characteristics such quality, quantity and distance from the central water resource; hippos can increase or reduce bite rate, food intake and movement speed when foraging in sites with higher grass quality or farther from the river (Lewison & Carter, 2004).
At night, hippos emerge for feeding solitary, females come out of the water in company of their calves; however, during the day hippopotamus’s behavior is gregarious. Males enforce mating territoriality to a shoreline of the river where the schools are, allowing in the groups only young males. The schools are unstable groups of polygynous females and their bachelors (Walzer & Stalder, 2015); which can sum up groups from 10 to 100 individuals.
The species’ reproduction strategy is really successful, in captivity, females can reach puberty as soon as 2-3 years old (Walzer & Stalder, 2015) and reach sexual maturity between the ages of 7 to 11 years (Flindt, 2006); yet, at the Magdalena River Basin females were observed to become reproductive at 5-6 years old (Subalusky, et al., 2019). Female hippopotamuses have an estrus cycle of 30 days, can have one calve every other year, the gestation lasts 240 days and the breastfeeding lasts 18 months. Thus, in total every female can have up to 25 calves during their lifetime of 50 years (Flindt, 2006; Walzer & Stalder, 2015; Lewison & Pluháček, 2017).
Hippopotamuses are hunted for many, purposes such as bushmeat or trophies, also people use the derivatives such the skin, bones, and organs for elaborating processed commodities and handcraft articles such wallets, belts, purses, or utensils as ropes. Since colonialism, articles made from hippo’s derivatives became available on the international market, with special interest for the hippo´s ivory; between 1950 to 1954, 12500 kg on hippo’s ivory pieces such carving, trophies and jewelry were exported from easter Nile region (CITES, 1994). Thus, given the pressure on the species resulting from trade, in 1975, pygmy hippos were included in Appendix III in the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES). However, in 1992 was detected that after the ban on elephant ivory trade, exports of hippo’s ivory rose, reducing dramatically wild populations; and, resulting, in 1994, on the amendment to the Appendix II for including Hippopotamus (CITES, 1994).
In the last 20 years, hippos´ international trade has been common from African countries like Zimbabwe, South Africa, Tanzania, and Mozambique; to significative importers such United States, Germany, Spain, France, and Hong Kong in Asia (CITES Trade Database; Williamson, 2004). Although the global trade of hippos includes living specimens, handcrafts, leather and skin products, the international market focusses specially on the Ivory trade (Outhwaite & Brown, 2018); it is estimated that for satisfying the international ivory trade between 2009 and 2018, 1349 hippos should have been culled each year; yet, most of the specimens are obtained from wild populations (CITES Trade Database; Moneron & Drinkwater, 2021). Furthermore, mismatches in trade volumes reports occur; frequently, Hong Kong reports on volumes imported are larger than volumes reported from the exporting countries in Africa (Weiler, Meulenaer, & Bloock, 1994; Andersson & Gibson, 2017).
Additionally, pressure for the species conservation in the native range includes urban expansion, agriculture, and large-scale development projects, which have cause habitat fragmentation, degradation. Human development has contributed to increased pressure on water resources, and caused land change, constraining suitable area for the species across Africa (Lewison & Pluháček, 2017). Thus, habitat pressure has risen the number of human and hippos’ mortalities resulting from the growing human- hippos’ conflicts; specially in countries with restricted areas for hippos, with high pressure from local communities, and in countries with civil unrest. Moreover, conflicts intensify during drought conditions (CITES, 1994; Lewison & Pluháček, 2017), when water is limited, and pastures are far; ecological trends restrict hippos’ growth and dispersal.
As a result, of legal and illegal hunting and habitat loss, the major threats for hippopotamus conservation; and the continued declining in populations, the International Union for Conservation of Nature (IUCN) has increased hippos’ conservation status over the past years. In 1965, the pygmy species was first included within the IUCN Red List of Threatened Species; then, in 1996, common hippos were listed. Since 2006 and a reassessed in 2016, pygmy species has been listed as Endangered and common hippos have been listed as Vulnerable (IUCN, 2012; Ransom, Robinson, & Collen, 2015; Lewison & Pluháček, 2017).
Drivers for ecological change in the neotropics
Hippopotamus’ behavior and ecology have great impacts on the landscape and ecosystems. In the Colombian neotropics, hippos are negatively impacting the novel ecosystem and affecting local communities, by displacing local biodiversity and modifying the ecological integrity of the MRB; additionally, are causing economic loses to farmers and fishermen. The alien herds of hippopotamuses are reducing space for humans to navigate on the rivers and are damaging crops and posing risk to public health acting as a diseases’ vector. Moreover, hippos are defined as ecosystem engineers because of the effects on the biotic and abiotic features of an entire landscape; and because the great size, the feeding behavior and effects on the flora are classified as mega-herbivores. Thus, impacts on the novel ecosystem are driven trough different means.
The Convention on Biological Diversity in recognition that alien species are major direct drivers of biodiversity loss around the world; and for addressing the negative impacts caused by alien species on ecosystems and biodiversity, specifically settled the Aichi Biodiversity target 9, for preventing, controlling, and eradicating biological invasions. Management actions for controlling invasions, have been expensive and unsuccessful. Established species compete for natural resources with local wildlife, modifies local ecological trends and negatively impacts ecosystems´ inhabitants (Lockwood, Hoopes, & Marchetti, 2007). Only in the US, 958 species are facing any extinction risk threatened by exotic species, Moreover, alien species, like domestic cats, have cause numerous species extinction in the world after their introduction (Pimentel, y otros, 2001). Likewise, invasive species affections on ecological features are difficult to quantify, however, Australia reported in 2012 a total cost of 13.6 million dollars in managing invasive species effects (Hoffmann & Broadhurst, 2016). It is specially challenging to measure negative impacts caused by amphibious herds, gracing at night when are less noticeable or assess effects in aquatic ecosystems.
Human-Hippos conflicts have been long documented in Africa. Rural populations like farmers, fisherman, mineworkers, and aquatic transporters conflicts frequently with hippos’ herds (Kahler & Gore, 2015). Nonetheless, despite the long history between humans and hippos, the species is extremely aggressive and dangerous; with no natural predators, it is occasionally reported attacks
to the juveniles by lions or crocodiles (Lewison & Pluháček, 2017). The speed, strength, body weight, the skull anatomy with the massive lower canines, makes from hippopotamuses a potentially harmful species. By yawning, hippos display the first threaten signs to intruders; they can open the jaw to a maximum of 150 degrees (Lewison & Carter, 2004; Walzer & Stalder, 2015).
Furthermore, wild hippos represent a threat to public health; wild hippos might act as vector to humans, livestock and wildlife in the transmission of infectious diseases like Brucella and Leptospira; and parasites like Fasciolidae, Ascarididae and Trypanosoma. Furthermore, studies have identified antibody titers to tetanus virus, and large outbreaks of Anthrax (Bacillus anthracis) have been documented in wild hippos’ populations (Walzer & Stalder, 2015).
Hippos are described as ecosystem engineers. Ecosystem engineers are species that modify biotic and abiotic components on a certain landscape or ecosystem, for creating and maintaining new habitats; consequently, modulates resources availability for other species. Hippos are allogenic engineers, which means that change the environment via mechanical means, and, after the species absence impacts a remain (Jhones, Lawton, & Shacak, 1994; Hastings, y otros, 2007). Thus, hippos cause physical disturbances especially in riverbanks, were spend daytime compressing the soil by the river, changing water courses, creating channels, and reducing soil´s infiltration capacity (Lewison & Pluháček, 2017); contributing with soil degradation, erosion and desertification (Hastings, y otros, 2007).
Moreover, hippos create changes in water chemistry and biological balance. Input of fecal material to water sources, form pastures ingested on the ground, changes the chemical and biological trends in in the aquatic ecosystem after decomposing; thus, modifies the comfort zone in the habitat for the local species such plants, fishes, and macroinvertebrates (Subalusky, et al., 2019; Shurin, y otros, 2020), forcing species to shift ranges and distribution over the area for finding another comfort zone. Likewise, ecosystems within MRB are important for storing and regulation of superficial water in a numerous wetlands’ ecosystems such swamps, lagoons, ponds, and lakes (Restrepo, 2005).
Additionally, hippopotamuses modify the terrestrial landscapes as consequence of the feeding behavior. At night, when hippos are moving and foraging, herds cause economic loses on field crops and pastures by compressing soil and pastures or feeding from them (Kahler & Gore, 2015). Likewise, hippos are selectively grazers and can choose amongst pastures and take them from the ground, thus; can over graze some species and facilitate growth of others like shrubs (Lewison & Pluháček, 2017; Subalusky, et al., 2019). Thus, changing plants composition and compressing soil, edaphic fauna composition and distribution shrinks. Soil fauna are organisms that spend a portion of their life cycles in the soil, and produce many ecosystem services such soil formation, nutrient cycling, soil restoration, improves aeration and water filtration (Mekonen, 2019). Thus, when hippos displace soil fauna facilitates erosion and desertification at the MRB; likewise, displaces fauna that feeds from soil fauna, causing disturbances in biological balances in aquatic and terrestrial ecosystems.
Magdalena River Basin, the novel ecosystem.
MRB is in Colombia, is formed by the central and oriental branches at the northern portion of the Andean cordillera, with a total surface of 257438 km2, comprises a total of 151 subsidiary basins; the Magdalena River source is at 3600 m.a.s.l. at Paramo Papas, has a length of 1550 km, with an average flow of 7,100 m3s-1, and a maximum width of 70 km (IDEAM-Cormagdalena, 2001). 80 % of the Colombian population lives within the MRB, distributed in 726 municipalities of the Andean and Caribbean regions, and 86% of the PIB is produced within the MRB (IDEAM-Cormagdalena, 2001).
The isolation of the MRB by the Andean cordilleras, facilitated the basin to hold high biodiversity values, especially in endemic species. The MRB is a highly biodiverse hotspot for conservation priority (Myers, Mittermeier , Mittermeier, da Fonseca, & Kent, 2000); and was recently mapped as priority hotspot for carbon storage and conservation of biodiversity values (Soto Navarro, y otros, 2020). Natural forest’s ecosystems within the MRB hosts a wide range of biodiversity, which change across the altitudinal ranges within the basin; likewise freshwater ecosystems accounts for more than 233 fish species described for the Magdalena River, 68 % of which are endemic (Jiménez Segura & Lasso, 2020).
Anthropogenic pressure on the basing is excessive. Changes in land use for agriculture and urban expansion have cause deforestation, erosion, and have impacted 74 % of the Basin surface. As a result of the high pressure on the ecosystem; the Magdalena River is negatively impacted. Magdalena River accounts to be the river in south American that holds higher rates of erosion (Restrepo, 2015). Likewise, additional pressure on the ecosystem threatens the river´s biological diversity; 34 fish species have been introduced. Furthermore, within the MRB livelihoods of more than 30000 people rely on upon freshwater natural resources (IDEAM-Cormagdalena, 2001). Thus, while hippos are posing high pressure on biological resources, habitants are under risk to be attacked by a hippo, and livelihoods obtention are becoming more challenging to obtain.
Discussion
Hippopotamus impacts are increasing with population growth. While hippo´s impacts after attacking humans, producing economic losses in crops, and reducing space for freely navigate and work on the MRB rivers are rapidly noticeable; impacts on ecological features will be evident in the long term. The MRB is already highly impacted by human communities; the landscape is extremely fragmented, is densely populated, and there is a lot of deforestation for implementing agricultural productions; causing erosion and large amounts of sediment into the Magdalena River. Therefore, hosting the largest invasive alien species, an extremely aggressive and dangerous animal, which is an ecosystem engineer, is rising pressure in the local ecosystem´s integrity and stability, in one of the most biodiverse and prioritized basins for conservation in the world. Moreover biotic effects will be evident in the long term, when consequences from competing, displacing and facilitating biodiversity loss at the MRB are unrepairable; and abiotic impacts, will be noticeable when results from modifications to the soil and riverbanks affects watercourses and change hydrological dynamics.
Herds of hippos in the wild are young individuals becoming adults. Animals that initially scaped were reproductive yet not entirely mature; given the novelty of the animals in the ecosystem, animals that scaped are firs generational groups of introduced individuals. This means that reproductive animals that scaped are reaching maturity stages of development, thus, starting to develop adult characters such territoriality and male displacement of young competitors, and increasing displays of threats demonstrations to intruders. Thus, in the highly populated basin, interactions between humans and hippos are to increase, when new young adults explore the territory looking to enforce territoriality in the basin. Likewise, females with calves are extremely aggressive, increased number of females in the territory is to conflict with humans, when protecting the calves.
Thus, management actions are urgently required for protecting human lives, for protecting biodiversity richness, for securing ecological integrity and for facilitating further ecological restoration actions on the MRB. Decision making should include scientific knowledge of the invasion ecology, yet there is still research needed for determining biotic interactions of the alien
species in the novel ecosystem. Increasing capacity building for studying the species in the wild is required; research on the on hippos’ ecology and impacts in wild aquatic and terrestrial ecosystems are needed; assessment of the number of individuals in the wilderness, and studies for stablishing a taxonomic study and the genetics introduced are important. Furthermore, given the novelty of the presence in the ecosystem, there is lack of traditional nor highly qualified technicians on the species management; thus, qualifying technicians abroad on the species management is to be considered.
Nonetheless, for fully avoiding negative impacts on the ecosystem, I agree with Castelblanco (2021) that, the best species management to implement is the complete removal of animals from the wild; and culling the most endurable method for protecting future impacts on the ecosystem. Nonetheless, considerations on the species conservation status should be minded. Although avoiding hippos keep reproducing in wilderness is the minimum goal to achieve, and practicing castration or sterilizing animals is the humanitarian solution to prevent long term effects in the ecosystem, demands long term monitoring for ensuring the complete castration of the reproductive population in the wilderness. And sterilizing animals do not reduce pressure on the species conservation status and threatens to habitants persist.
However, removal for cropping hippos should be considered. Hippos are widely trade worldwide under the CITES regulations. Furthermore, in the 2017 hippos´ reassessment for the IUCN Red List, within the actions needed for the species conservation, includes the species management ex-situ and captive breeding (Lewison & Pluháček, 2017). Thus, building capacity in Colombia for breeding hippos is to be considered. By producing sustainable market alternatives of hippos’ goods; might reduce pressure on hippos at the native range for ivory obtention. Removing hippos from wilderness and relocating them in adequate enclosure for captive breeding, is to reduce pressure on the species, lessen illegal hunting and illegal trade, by providing the international market with hippo’s derivatives. Furthermore, Colombia as a CBD signature party is committed to achieve international conservation goals, and is dedicated in developing green strategies and markets to accomplish the Sustainable Development Goals and the Paris Agreement; and enhance businesses with sustainable use of natural resources and increasing income from biodiversity (CONPES, 2018); thus, the invasion management becomes an opportunity for supporting hippo’s conservation, after the ecological risk is controlled.
Conclusion
MRB is a priority area for biodiversity conservation, however, is a fragile and highly impacted ecosystem; hippopotamus invasion will further negatively impact biotic and abiotic features in the ecosystem, causing ecological change, and worsening ecological degradation within the basin. A wide range of actions for controlling and mitigating impacts on the environment are urgent; however, building capacity is essential for succeeding in the species´ management, for preventing conflictive interactions with humans, reduce economic loses, avoid further pressure on the MRB and prevent an ecological catastrophe.
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