Hypotheses:
1. social organization,
2. varied diet (omnivorous diet based on fruits, acorns, roots, tubers, bulbs, rhizomes, insects and small mammals AND increase in the availability of cultivated plants,, ...),
3. reproductive system (high fertility, early first reproductive age, large size, high potential life expectancy,gestation time which is very short ),
4. low hunting and catching pressure,
5. extinction and regression of its natural predators especially the panther and the jackal,
I am not very strong in mammal ecology, but in my opinion in Latvia one of factors for the population growth was (!) hunting, e.g. - animal fattening and saving females.
It seems your question implies that the wild boar population is growing in the Atlas mountains in Morocco. Interesting! Increasing in number, geographically or both? Currently, such population growth is observed indeed in areas across Eurasia, to the extent that wild boar is considered a pest by farmers and suburban gardeners. All the points you mention may play a role, in various combinations depending on the locality. The overall reason seems to me rural depopulation, or its mirror image increasing urbanisation and associated decline of hunting and poaching pressure over large areas. Also effective hunting prohibitions in protected areas and the increase in the latter seem to play a role.
The trend meets the current accelerated geographic expansion of African swine fever (ASF) epidemic across Eurasia with the wild boar as actual and potential host. In an attempt to control the spread of ASF, new hunting regimes and regulations are applied, that is shooting females before their first pregnancy. So far, hunting seems to be effective in population control in dominantly agrarian landscapes, but not yet in extensive forested areas.
The least likely regulator of wild boar population size seems to be non-human predators. Most predators were in decline or vanished long before the current wild boar population boom. In various areas carnivore populations were growing in tandem with a wild boar population boom (e.g. in my Majella research area: wolf and wild boar). Further, sizable wild suid populations in the teeming wildlife areas in Africa seems to live side-by-side with healthy and diverse carnivore populations.
Thank you for Mrs Hein Van Gils and Martins Kalnins
based on data collected during 2008-2018 (not yet published)
the wild boar population of the Moroccan High Atlas Mountains are currently experiencing:
1. overpopulation because of the explosion of its effectifs;
2. increase in its range;
3. increase in cases of aggression against inhabitants.
The numbers of wild boars declined during the 80s and 90s of the 20th century, and then increased significantly in recent years. Currently, wild boar is abundant.
It damages the crops and devastates important surfaces of the spontaneous flora. This animal is the main pest of crops in the central High Atlas (EL ALAMI, 2014). Until the end of the twentieth century, the boar was still present, but without causing these problems. The increase of its populations and the change of its behavior are surely a consequence of the imbalance of the ecosystem in the region of the study, because of the extinction of several mammals, in particular the carnivores, and the pressure exerted on forest resources
I can make an example for Italy, where I live and work.
In Italy there was a similar trend, with wild boars declining all over the peninsula almost on the verge of extinction due to over hunting and habitat destruction.
Also to the natural predators of wild boars (wolves, bears) were reduced to the verge of extinction.
The Italian wild boar was relatively small, if compared to central European wild boars and had a low reproduction rate.
Then in Italy there was a deliberate introduction of wild boars from Central European areas by hunters associations that increased the size of the animals and moreover the Italian wild boars also mated with semi-wild pigs (in Italy there are/were some pigs, for example Cinta Senese, that were reared in a semi wild condition and could easily meet wild boars).
The mating with pigs increased the wild boar reproduction rate, therefore the present population in Italy is combination of the relatively small Italian wild boar, a very reproductive pig and the big European wild boar.
The combination of these factors and the abandonment of rural areas that are now reinvaded by forests helped to recover the populations of wild boars that are now reaching impressive numbers. they are now aggressively invasive and destroy cultivated fields and have also negative impact also in some forest environments.
They are a sort of semi-invasive species, in the sense that they are no more the original wild species, although they are not completely alien to their environment.
Dear Mr El Alami,
I agree with Martins concerning the females. In Hungary, totally accepted that shooting females with piglets is forbidden. The wild boar situation in a mountainous area, I quess, is more different than here (plains and hilly region), but I think their flexibility to changes and persistence are the main factors.
I also agree with You concerning the wide range of diet, and the population of ground nesting bird species (eggs) could effect its distribution. To study the seasonal varation in diet, landscape changes (e.g. farming, forestry, mining) or regional climate change may be important. In Hungary, golden jackal (Canis aureus) is a natural predator and they can catch piglets, but wild boar gives a low proportion of its diet (Hungarian view). Here, large-scle farming (as feeding & resting) has a positive effect on wild boar population. Hunting pressure should intensify, I think.
The main factor shaping the population growth of wild boar is nutrition. However, climate canges, changes in agriculture/landscape and in human behaviour (esp. changes in ethical aspects of hunting) are also important drivers.
How to manage wild boar?
Manage them and do not hunt them as a leisure activity...!
I have already been in contact to colleagues in Algeria with the same problems.
There is a lot of literature on these topics.
Thus, no real need to discuss and especially to speculate here
Best
Oliver
e.g.
Bergqvist G, Paulson S, Elmhagen B (2018) Effects of female body mass and climate on reproduction in northern wild boar. Wildl Biol 2018:wlb.00421 doi:10.2981/wlb.00421
Frauendorf M, Gethöffer F, Siebert U, Keuling O (2016) The influence of environmental and physiological factors on the litter size of wild boar (Sus scrofa) in an agriculture dominated area in Germany. Sci Total Environ 541:877–882 doi:10.1016/j.scitotenv.2015.09.128
Gamelon M, Focardi S, Baubet E, Brandt S, Franzetti B, Ronchi F, Venner S, Sæther B-E, Gaillard J-M (2017) Reproductive allocation in pulsed-resource environments: a comparative study in two populations of wild boar. Oecologia 183:1065-1076 doi:10.1007/s00442-017-3821-8
González-Crespo C, Serrano E, Cahill S, Castillo-Contreras R, Cabañeros L, López-Martín JM, Roldán J, Lavín S, López-Olvera JR (2018) Stochastic assessment of management strategies for a Mediterranean peri-urban wild boar population. PLOS ONE 13:e0202289 doi:10.1371/journal.pone.0202289
Keuling O (2009) Managing Wild Boar - Considerations for wild boar management based on game biology data. PhD thesis, Dresden University of Technology
Keuling O, Baubet E, Duscher A, Ebert C, Fischer C, Monaco A, Podgórski T, Prevot C, Ronnenberg K, Sodeikat G, Stier N, Thurfjell H (2013) Mortality rates of wild boar Sus scrofa L. in central Europe. Eur J Wildl Res 59:805-814
Keuling O, Podgórski T, Monaco A, Melletti M, Merta D, Albrycht M, Genov PV, Gethöffer F, Vetter SG, Jori F, Scalera R, Gongora J (2018a) Eurasian Wild Boar Sus scrofa (Linnaeus, 1758). In: Melletti M, Meijaard E (eds) Ecology, Conservation and Management of Wild Pigs and Peccaries. Cambridge University Press, Cambridge, pp 202-233. doi:10.1017/9781316941232
Keuling O, Sange M, Acevedo P, Podgorski T, Smith G, Scandura M, Apollonio M, Ferroglio E, Vicente J, consortium E (2018b) Guidance on estimation of wild boar population abundance and density: methods, challenges, possibilities. EFSA Supporting Publications 15:1449E doi:doi:10.2903/sp.efsa.2018.EN-1449
Keuling O, Strauß E, Siebert U (2016) Regulating wild boar populations is “somebody else's problem”! - Human dimension in wild boar management. Sci Total Environ 554–555:311-319 doi:http://dx.doi.org/10.1016/j.scitotenv.2016.02.159
Malmsten A, Dalin A-M (2016) Puberty in female wild boar (Sus scrofa) in Sweden. Acta Veterinaria Scandinavica 58:55 doi:10.1186/s13028-016-0236-1
Malmsten A, Jansson G, Dalin A-M (2017a) ‘Post-mortem examination of the reproductive organs of female wild boars (Sus scrofa) in Sweden’. Reproduction in Domestic Animals:n/a-n/a doi:10.1111/rda.12947
Malmsten A, Jansson G, Lundeheim N, Dalin A-M (2017b) The reproductive pattern and potential of free ranging female wild boars (Sus scrofa) in Sweden. Acta Veterinaria Scandinavica 59:52 doi:10.1186/s13028-017-0321-0
Massei G, Kindberg J, Licoppe A, Gačić D, Šprem N, Kamler J, Baubet E, Hohmann U, Monaco A, Ozoliņš J, Cellina S, Podgórski T, Fonseca C, Markov N, Pokorny B, Rosell C, Náhlik A (2015) Wild boar populations up, numbers of hunters down? A review of trends and implications for Europe. Pest Manage Sci 71:492-500 doi:10.1002/ps.3965
Melletti M, Meijaard E (eds) (2018) Ecology, Conservation and Management of Wild Pigs and Peccaries. Cambridge University Press, Cambridge. doi:10.1017/9781316941232
Oja R, Kaasik A, Valdmann H (2014) Winter severity or supplementary feeding—which matters more for wild boar? Acta Theriol 59:553-559 doi:10.1007/s13364-014-0190-0
Santilli F, Senserini D (2016) Potential impact of Wild boar (Sus scrofa) on Pheasant (Phasianus colchicus) nesting success. Wildl Biol Pract 12:15-20
Skjerve E, Thurfjell H, Flø D, Grahek-Ogden D, Malmstrøm M, Nesbakken T, Neves CD, Nielsen A, Pedersen HC, Robertson L, Rueness EK (2018) Wild boar population growth and expansion –implications for biodiversity, food safety, and animal health in Norway. Opinion of the Norwegian Scientific Committee for Food and Environment.
Tabak MA, Webb CT, Miller RS (2018) Propagule size and structure, life history, and environmental conditions affect establishment success of an invasive species. Scientific Reports 8:10313 doi:10.1038/s41598-018-28654-w
Vetter SG, Ruf T, Bieber C, Arnold W (2015) What is a mild winter? Regional differences in within-species responses to climate change. PLoS ONE 10:e0132178 doi:10.1371/journal.pone.0132178
Thank you fo all (Marco Ciolli, Tamás Márton Németh, Oliver Keuling )
In the morrocan High Atlas, thewild boars also mated with semi-wild individualsreleased by the authorities when the numbers of wild boars are low (80s and 90s of the 20th century).
In this region, the wild boar consumes a wide range of foods. and its ability to adapt allows it to survive in diverse habitats and colonize new environments.
but a new behavior is being recorded in the wild boars of the High Atlas, it is aggressiveness towards the inhabitants (death and injury)
I Thank Mr Oliver Keuling for references.
I echo the comments by Martins Kalnins re the reasons for the increase in Latvian wild boar. I did a study on the conflict over the management of wild boar back in 2012, Article Wildlife Management Conflicts in Rural Communities: A Case-S...
) and hunting for leisure as Oliver Keuling points out was one of the contributory issues, along with a lack of predators. We do have wolves but not enough to keep the wild boar under control. Disease and strong hunting pressure to contain the disease did result in a dramatic drop in numbers recently but as a part-time farmer we have noticed this has started to reverse again, judging by the increase in damage we are already seeing this year.
Yes, the wild boar is able to increase its numbers after decreases related to natural factors or the impact of man. It has a high adaptive capacity and an immediate response to factors that can decrease its population.
In the mountains of the Moroccan High Atlas, legal (by the authorities) and illegal (by the inhabitants and hunters) Hunting session performed to kill a large number of wild boars are carried out to fight against wild boars. The aggressiveness of wild boars in these can be explained by the use of these inadequate methods to control this animal. In the majority of attacks (deaths and injuries), wild boars attacking the inhabitants are wounded or hunted during the beatings. (photo: Photo of a boar killed during a threshing session in the High Atlas, Morocco).
some references
OUBELLIL D. 2011. Sélection de l’habitat et écologie alimentaire du chacal doré Canis aureus algirensis dans le parc national de Djurdjura. Mémoire de Magister. Université Mouloud Mammeri de Tizi-Ouzou, Algérie.
SERVANTY S. 2007. Dynamique d’une population chassée de sangliers (Sus scrofa scrofa) en milieu forestier. Thèse Doctorat. Université Claude Bernard-Lyon 1, France.
TSACHALIDIS E.P. & HADJISTERKOTIS E. 2008. Wild boar hunting and socioeconomic trends in Northern Greece, 1993- 2002. Eur. Journ. Wildl. Res. 54: 643-649.
UEDA G. & KANZAKI N. 2005. Wild boar hunters profile in Shimane Prefecture, Western Japan. Wildl. Biol. Pract. 1(2): 146-151.
PANOUSE J.B. 1958. Les Mammifères du Maroc: Primates, Carnivores, Pinnipèdes, Artiodac-tyles. Travaux de l’Institut Scientifique Chérifien et de la Faculté des Sciences. Série zoologique 5: 1-206.
ONIDA P., GARAU F., COSSU S. 1995. Damages caused to crops by wild boars (S. scrofa meridionalis) in Sardinia (Italy). Ibex J. Mt. Ecol. 3: 230–235.
Excellent review by Melis et al 2006 concluded that the key determinants of wild boar density were:
- Winter temperature
- Followed by primary productivity
- With predation (wolves) an important but weaker limiting factor:
Article Biogeographic variation in wild boar (Sus scrofa L.) density...
Thank you very much Dear collegue Andrew P. Stringer for this reference.
All the factors already mentioned are likely to affect wild boar populations growth but as my colleague Oliver Keuling have explained the problem in North Africa at least in Algeria and I think in morroco and Tunisia also, is the fact that it does not exist a management plan for wild boar hunting. We hunt for leisure so we miss information that allows us to have an overview on population trends.
We can say that wild boar populations are increasing, decreasing or stable if we don't have an evaluation indicators Oliver Keuling .
Best
Fatima
See article: The Hunting Trends of Wild Boar (Sus scrofa) Hunters in Northeastern Algeria.
Hi everyone, I think the question of Abderrazak it is very interesting.
When I think about this question, we can talk about several factors as Oliver proposed, however, an important issue that alters the "weight" of these factors is the character of "introduced" or "native" of the boar. Because, for example, this determines whether the wild boar has natural predators (eg tiger in Asia) or natural foods (eg acorn in Europe), which often determine the stability of their populations. At the southern tip of South America, the wild boar is an invasive exotic species that grows out of control and its populations colonize new territories year after year. The causes are multiple, for example the lack of natural predators is one of them. On the other hand, in my opinion plasticity in their diet and in the use of environments allows the species to successfully disperse in this region. I believe that these two characteristics of the species are those that allow the wild boar to adapt to these times of change in the anthropocene.
Research does indeed back up your opinion, Sebastian Bellari
This is perhaps a place to start "Wild Boar (Sus scrofa). Populations in Europe: A scientific review of population trends and implications for management" by Dr. Jurgen Tack
- Badges
- Science topic