REPORT ABOUT IMPORTANCE OF DOMESTIC CATTLE CARRIONS FOR CANTABRIAN BROWN BEAR CONSERVATION
November 2006
Developed by:
Alfonso Hartasánchez, Fondo para la Protección de los Animales Salvajes (FAPAS)
Francisco J. Purroy, Animal Biology Professor, University of León IMPORTANCE OF DOMESTIC CATTLE CARRIONS FOR BROWN BEAR CONSERVATION
LEGAL BACKGROUND
On may the 22nd 2001, European Union Diary, published the Regulation 999/2001, which establishes measures for prevention, control and eradication of Bovine Spongiform Encephalopathy1, better well known as o 'mad cow disease'. This disease is caused by an infectious transmissible agent called prion, accumulated in cattle's nervous system neurons provoking cell's death.
The current regulation demands that all infected sources should be controlled and eliminated; this implicates that death animals body with can potentially be infected, has to be removed from natural areas and destroyed in appropriate conditions. The reason is that the encephalopathy can only be diagnosed from brain nerves tissue taken from death animals.
Since then, it starts an obligatory collection of domestic animal dead bodies which are moved to crematorium ovens to avoid not controlled elimination.
The Service of Sanitary Alerts from Asturias Regional Government, has reported on year 2004 a removal of more than 17.000 animal bodies to be cremated. Before the european regulation comed in to effect, most of them would've been consumed as carrion by wild animals.
NEGATIVE EFFECTS OVER GENERAL FAUNA CAUSED BY REMOVING ANIMAL BODIES
Carrion-eating birds of prey are species of fauna which populations clearly depend on the presence of carrion on natural areas; among these species stand out the gryffon vulture (Gyps fulvus), the egyptian vulture(Neophron percnopterus) and the bearded vulture (Gypaetus barbatus), to quote the most significant. In order to avoid the decline of the considerant amount of carrion-eating birds existing in our country, the Spanish government published on 2002 a Royal Decree which gather the legal orders needed to accomplish the installation of carrion feeders, so it could be insured carrion-eating birds survival.
However, the negative effects of animal bodies removal over mammal's populations, seems to have go unnoticed, maybe because the fact that big carnivorous are only perceived as predatory species. In the particular case study of Brown Bear (Ursus arctos), which this report is referred to, is characterized by its short predation habits and to resort frequently to carrion ingest (Braña et al., 1993; Clevenger et al., 1994).
1 BSO from now on POTENTIAL AND CURRENT DISTRIBUTION OF BROWN BEAR IN CANTABRIAN MOUNTAINS
Cantabrian brown bear is an unique natural heritage, from genetic point of view, and it is at the same time one of the most threatened population from all Europe. The brown bear (Ursus arctos), an old inhabitant of practically all our forest and mountain chains, has at the present time less than 130 specimens that survive spread in two focus of Cantabrian Mountains, and although they exchange specimens with sporadic frequency, the two population can be considered as genetically isolated.
RESEARCHES DEVELOPED TO DETERMINE THE IMPORTANCE OF CARRION ON BROWN BEAR'S FEEDING
Since feeding resources availability is one of the key factors for brown bear reproduction success, scientific researches have been developed in order to determinate relatively importance of carrions on brown bear's diet during different seasons of the year:
1. Analysis of carrion leftovers in a sample of 929 bear excrements. University of León, Spain (2000-2004) and University of Tennessee, United States (2000-2004).
2. Monitoring of 24 carrions though photograph-trapping. FAPAS (2004-2005)
1. Out coming of analyse of carrion leftovers in brown bear excrements
By analysing 929 brown bear excrements contents collected in Cantabrian Mountains (Clevenger and Purroy, 1991; Clevenger et al., 1992), composition of brown bear diet have being set. These analyses confirm the constant presence of ungulates and domestic cattle remains obtained as carrion in bear's diet.
By mean of the aforementioned research, excrements were collected through all year with in order to obtain information of carrion presence in different seasons which coincide with bear's different life cycles. Steam from these analyses could be stated the following data of carrions volume in excrements:
· During spring, the volumetric percentage of carrion in excrements rises to 9%. It needs to be emphasize, that during years with big snowfalls and high deer and roe deer death toll, the volume got to represent an 89%.
· In summer, cattle remains mean 12% of volumetric percentage, mainly from sheep's carrion (7%) and cow's carrion (5%).
· Autumn feeding, presents also a high value of volumetric percentage of carrion (11%). From this volume, 80% belongs to cows remains, 10% to sheep and 10% to wild ungulates (during hunting periods some of the headless specimens of deer and roe deer stay at the forest) · During the winter, carrion represents a faecal volume of 5%. 80% of this percentage belongs to equine and 20% to wild ungulates.
2. Out coming from monitoring of 24 carrions though photograph-trapping
The organization Fondo para la Protección de los Animales Salvajes2, FAPAS, carried out between years 2004-2005 monitoring works of 24 carrions using photograph automatic cameras located close to each of them. The aim of this research was to know, through the images obtained, what was the utilization intensity of carrion by bear population3 as a feeding resource.
The 24 carrions controlled by photographic monitoring become from old horses, which are not specified as risk specimens in BSA regulations. These specimens where took to plots placed into bear's area and they where consumed as follows:
· On 2004, from 10 carrions placed, 7 of them (70%) were consumed by bears
· On 2005, from 14 carrions placed. 10 of them (71%) were consumed by bears
One of the aims of this study, was to repeat the situation occurred in three Asturian municipalities4 where bear presence is usual, and which carrions location would be similar to its habitual distribution in the frame of traditional agrarian uses. This way we could imitate what have been happening in the area during hundred of years.
Conclusions taken out from both studies
Although, brown bear is able to adapt itself to cantabrian forest's rate production, consuming the resource offered by the environment, there are two critical moments along the year when the proteins supply is fundamental in order to ensure reproduction success of this specie which specimen's number are in a critical situation, threading the future of this natural relic refugee in Cantabrian Mountains:
· Post-winter period (early spring), when bears leave their caves after winter sleep
· Autumn-early winter period, specially during years with low rates of fruits production
In both cases, natural carrion availability, consumed systematically by bears, becomes an additional food supply in moments of high nutritional stress.
2 Association for Protection of Wild Animals 3 Population composed by solitary specimens adult and young, and two reproductive females with cubs 4 Concejo de Somiedo, Concejo de Belmonte de Miranda y Concejo de Proaza (Asturias) · Importance of domestic cattle carrions in spring. This period, from February to April, coincides with a high feeding activity for bears after the hibernation, when this plantigrade comes out from its winter lethargy, and has undergone a great lost of weight and fat reserves which have to be recovered. This unfavourable corporal condition force bears to search immediate feeding resources.
During this period, food's availability is very low, limited to wild animals carrions and the fruits that remain conserved in the floor from previous autumn (bot chestnut and acorn). Both resources are very variable because they depend on climatic fluctuations and trees productivity. Like this, heavy winters with strong snow-covered, provoke the death of wild ungulates, but not during winters with smooth climate. In the other hand, rainy winters cause the rapid waist of fruits fallen to the floor, because they get rotten or eaten by insects, herbivore mammals (rodents, wild boars and deers) and birds. During this rainy winters there is not any fruits left by January.
This way, early spring is one of the greatest feeding stressing moment on bear's life cycle that has lost around 30% of its corporal volume due to hibernation. Though the consumption of a diet rich on proteins, bears are able to recover around one kilogram of weight by day.
FOTOGRAPH 1 (April the 26th of 2005) – Female bear eating carrion on spring 2005. FOTOGRAPH 2 (April the 27th of 2005)- Adult male bear marking a tree located close to a carrion left over
· Importance of carrions during rut period (Summer)
Ones bears come overcome winter lethargy crisis, new biological shortages appear because the bear go through reproduction period and males have to cover long distances looking for the few females left in the Cantabrian Mountains. In addition, the females select inaccessible areas to avoid meetings with males in heat that can attack their cubs. This fact becomes a delicate circumstance due to the low number of females in the territory.
Summer is the season of pulp fruits , and in spite of bot cherry and hazelnut help to improve food resources, but their production is quite irregular.
During this period the livestock uses high mountain pastures, open territories which become very suitable for carrion-eating birds feeding which can get domestic animal bodies, so in this case the competence for the carrion is greater for bears. Furthermore, the heat accelerates bodies decomposition that can disappear in less than ten days without been consumed, not just by bear, but by any fauna specie. · Importance of carrion for cubs survival during their first year alive
Brown bear is a specie with strong links among the mother and its descendants and has a high rate of death toll during the first five years of cubs life. The habit of eating carrions, serve as learning for cubs and allows to ensure the good well physical state of bear cubs to face the first months of life alone.
FAPAS team could photograph two litters from the same mother on consecutive years. One of them had an additional supply of carrion but not the other one. The graphic proofs turn out obvious: while the bear cubs from the first labour show an absolute malnutrition state in the moment of their independent life (see photograph 4), physical appearance of bear cubs from the second litter is excellent (see photograph 3).
The nutritional state of brown bear condition the following parameter:
· First reproduction age · Litter size · Labour intervals · Bear cubs survival rate FOTOGRAPH 4 (June the 11th of 2004) – Bear cub from first litter that had not additional carrion supply. The malnutrition signs are clear
FOTOGRAPH 3 (April the 30th of 2005) – Bear cub from second litter which had carrion supply. The image reflect a good nutritional state. INTEGRATION OF BROWN BEAR CONSERVATION AND BSA ERADICATION PROGRAMMES
Among the guidelines contained into the National Strategy for Brown Bear's Conservation, the section 5.2.1.3. establish the need of “steer habitat management actions using restoration, conservation and management criteria, which guarantee the improvement and access of bear specimens to feeding resources”.
As well, the Brown Bear Recovery Plan in Asturias (Decree 13/91, from January 24th) considers as working objective, to have disposal of an additional feeding programme that guarantee feeding resources in case of borderline situations. This aspect has been specified in section 1.8. “ Contribution, in cases where is require, with feeding supply located in not fixed places in order to alleviate the possible negative effects stem from low availability of feeding resources”
Nowadays, in Asturias, due to livestock bodies gathering, we are witnesses of the disappearance of carrions along bear territory. In the other hand, BSA doesn't affect to asturian breed cows5 that graze in bear areas. The only breed that has suffer from this disease was the 'Holstein cows' which are kept in stables. We can't forget the fact that the common practice from livestock farmers of bury animals death bodies in appropriate locations, kept off from towns and public running waters, are traditional activities among Cantabrian Mountain shepherds.
We also know, that habitat quality and availability of feeding resources determines bears reproduction, being a common fact that females better feed are the ones that have litters more numerous and frequents in an early time.
Long term bear's conservation is unthinkable, if actions directed towards carrions availability in its environment, are not carried out. This should be done, without any kind of doubt, with environmental responsible administrations controls and cautions.
The current policy of death animals gathering because of sanitary reasons, eliminates 100% of spring and winter carrions from humanized rural areas.
European regulation is not taking into account the singularity of extensive farming from southern European countries, which is developed integrated in a natural environment with great ecological values.
It is necessary to integrate the unique biological heritage conservation of these countries with BSA eradication programmes in certain way that ensure sanitary security of human and sensitive animals population.
Carrions coming from extensive farming are part of certain species feeding along its cycle of life or during specific critical moments of its life. The elimination of this feeding resource, can entail towards drastic populations reduction or even its extinction.
Once we have identified the greatest feeding stress moments for bears, right after leaving the hibernation cave in spring, and along autumn-winter periods with few fruits available in the environment, we consider it is a need to improve bears feeding as a determining factor of reproduction and cubs survival. This actions should be guarantee with a legal moratorium which allows the abandon of death cattle in those bear areas where still exits seasonal high mountain grazing.
5 Vaca asturiana de los valles Documental and legislation references
· Reglamento (CE) nº 999/2001 del Parlamento Europeo y del Consejo, de 22 de mayo de 2001, por el que se establecen disposiciones para la prevención, el control y la erradicación de determinadas encefalopatías espongiformes transmisibles
· COMISIÓN NACIONAL DE PROTECCIÓN DE LA NATURALEZA. 2000. Estrategia de Conservación del Oso Pardo Cantábrico. Ministerio de Medio Ambiente. Madrid.
· DECRETO 9/2002, de 24 de enero, por el que se revisa el Plan de Recuperación del Oso Pardo (Ursus arctos) en el Principado de Asturias.
· FAPAS (2005) Informe sobre utilización de las carroñas por fauna salvaje en Asturias 2004- 2005
· Camiña, A. (2004). Consequences of Bovine Spongiform Encephalopathy on breeding success and food availability on Spanish vulture populations. En: Chancelor, R.D. & B. U. Meyburg eds. 2004, Raptors Worldwide. WWGB/MME.
· Braña, F., Naves, J., Palomero, G. (1993). Hábitos alimenticios y configuración de la dieta del oso pardo en la Cordillera Cantábrica: En Naves J. y Palomero, G. (eds). El oso pardo (Ursus arctos) en España: 81-103. ICONA. Madrid.
· Clevenger A..P. y Purroy , F. J. (1991). Ecología del oso pardo en España. Museo Nacional de Ciencias Naturales. CSIC. Madrid.
· García Garitagoitia, J.L., Alda Pons, I, Doadrio, I. (2004). Estudio genético del oso pardo cantábrico en Asturias.
· Berdocou,C., Faliu, L., y Barrat, J. (1982). Ke régime alimentaire de l’ours brun des Pyréées. Bull. Mens. O : N. Chasse 54 : 34-45.