The Coprophilous mycoflora of herbivores of the Kruger National Park, South Africa

Abstract

As a result of the taxonomical research a number of new records was established and a new species of the genus Trichodelitschia was described. In all 15 new records for the Southern Hemisphere; 18 new records for the African continent and 21 new records for South Africa were noted. Thus up to 70% of all the species recorded are new records for the Republic of South Africa. A number of extremely rare species were encountered, some of which were previously only known from the type locality. A relatively small number of the fungi recorded could not be identified to species level, these mostly belonged to fungal groups that are not normally reported from dung substrates. The largest number of fungal species belonged to either the Pyrenomycetes or the Discomycetes. The order Pezizales was well represented and a key to the coprophilous genera of this order was compiled (see addendum A). As a result of the ecological research it was possible to conclude that the feeding habits, food preferences and to a lesser degree the type of digestive systems had a definite influence on the fungal species composition and species diversity on the different dung substrates investigated. The existence of a forest-canopy coprophilous fungal flora and a grassland coprophilous fungal flora were established. These phenomena were attributed to the difference in fungal propagule sizes and the spore dispersal mechanisms as exhibited by the species on the different dung substrates. A comparison between the fungal species diversity on freshly voided dung substrates and substrates from different parts of the digestive tracts of the animals confirmed that the spores of the coprophilous species survive passage through the digestive system and are probably stimulated to germinate by the digestive processes. A comparison between the fungal species composition and the species diversity on freshly voided elephant dung substrates obtained from free roaming animals and animals kept in captivity were carried out. The results indicated a markedly lower fungal species diversity on the latter dung substrates. The possibility that these results could be indicative of a nutritionally related stress syndrome in the environment of the animals were implied, however the results could also be indicative of a lower fungal inoculum present on the food sources of the captive animals. With regard to the seasonality of fruiting of the coprophilous fungi the present research results differed from the observations of other authors in that the summer months proved to be the most productive period. However, the summer season in the study area represent the annual warm wet period and as such the results do concur with those of other authors. The fungal fruit body succession on the different dung substrates was investigated and the successional phases determined by means of a computer cluster analysis program. The conclusion was reached that the successional patterns exhibited could in all probability be attributed to a number of environmentally limiting factors and biotic pressures as well as the existence of inherited physiological characteristics exhibited by the fungi. Certain species associations were delimited by means of a computer cluster analysis program, these associations were found to be indicative of the peak ecological periods as exhibited by the members of each association. One-dimensional ordinations, with regard to the total overall ecological importance values, were constructed. These results lead to the arrangement of the coprophilous fungal species in order of ecological importance. A comparison between the fungal species composition and the species diversity on freshly voided elephant dung substrates obtained from free roaming animals and animals kept in captivity were carried out. The results indicated a markedly lower fungal species diversity on the latter dung substrates. The possibility that these results could be indicative of a nutritionally related stress syndrome in the environment of the animals were implied, however the results could also be indicative of a lower fungal inoculum present on the food sources of the captive animals. With regard to the seasonality of fruiting of the coprophilous fungi the present research results differed from the observations of other authors in that the summer months proved to be the most productive period. However, the summer season in the study area represent the annual warm wet period and as such the results do concur with those of other authors. The fungal fruit body succession on the different dung substrates was investigated and the successional phases determined by means of a computer cluster analysis program. The conclusion was reached that the successional patterns exhibited could in all probability be attributed to a number of environmentally limiting factors and biotic pressures as well as the existence of inherited physiological characteristics exhibited by the fungi. Certain species associations were delimited by means of a computer cluster analysis program, these associations were found to be indicative of the peak ecological periods as exhibited by the members of each association. One-dimensional ordinations, with regard to the total overall ecological importance values, were constructed. These results lead to the arrangement of the coprophilous fungal species in order of ecological importance.