Relict Forest Research Articles

Biogeography, Diversity and Seasonality of Syrphidae (Diptera) in a Guineo-Congolian Rain Forest in Kenya

Syrphidae (Diptera) were collected from different sites in Kakamega Forest, the only dry guineo-congolian rain forest relict in Kenya. In addition, literature records were compiled and old collections specimens were re-identified. In total, 74 species or 43 % of the known syrphid fauna in Kenya, were identified. The fauna indicates a biogeographical affinity with the main central and western African rain forest belt, with 12 out of the 74 species being indicator species for such a link. The alpha and beta diversity were compared at four sites, representing the main ecological habitats within the forest complex. Mostly undisturbed forest habitat shows the highest diversity. It also harbours a large proportion of the indicator species (seven out of 12). Natural glades in the forest show a low similarity with the other habitats, indicating the more exceptional fauna of the natural grasslands. The seasonal fluctuations for the more abundant species are briefly discussed. Most species reach highest abundance during the dry season.

Effects of Habitat Fragmentation on Bird Species in a Relict Temperate Forest in Semiarid Chile

Abstract:We analyzed the structure and composition of a bird assemblage in a fragmented relict temperate forest located in northcentral Chile ( Fray Jorge National Park). In terms of species composition, the bird assemblage we found in Fray Jorge was more similar to southern temperate forest sites, located more than 1200 km south of Fray Jorge, than to localities found in nearby scrub habitats. The relict character and long‐term isolation of the Fray Jorge forest provides a natural experiment with which to establish the potential long‐term effects of fragmentation and isolation on southern Chilean temperate forests. Between May 1996 and March 1997, we conducted seasonal surveys of birds in six forest fragments, ranging in size from 0.5 to 22.5 ha, at Fray Jorge. The number of bird species at each forest fragment was positively correlated with fragment area during all seasons. The relict forest system had a steeper species‐area slope than that reported for similar temperate‐forest bird assemblages in forest fragments within Chiloé Island and for islands across the Chiloé Archipelago in southern Chile. In this regard, this bird fauna resembled a depauperate oceanic archipelago. This difference in area effects is likely a consequence of the minimization of rescue effects because of the absence of large source forest areas nearby and the long‐term isolation of the system. In addition, the distribution of species among forest fragments in Fray Jorge was not random, showing a nested subset pattern. Thus, some species occur across all fragments, regardless of their area, and therefore are less affected by habitat fragmentation and less prone to local extinction. These results suggest that, for south‐temperate forest birds, large fragments (or reserves) should afford better protection against extinction than small forest patches.

Effects of urbanization on transmission of human African trypanosomiasis in a suburban relict forest area of Daloa, Côte d'Ivoire

The epidemiological risk of human African trypanosomiasis transmission was evaluated from entomological parameters (apparent trap density, female teneral rates, daily survival rates, proportion of human feeds) of tsetse ( Glossina palpalis palpalis) populations in the town of Daloa, Côte d'Ivoire. High tsetse densities were found in the town outskirts, where the calculated risk of transmission was greatest. Environmental changes brought about by urbanization did not result in the disappearance of tsetse, or the interruption of sleeping sickness transmission. The few cases of sleeping sickness detected (32) in the years 1990–1995 indicated that transmission was unrelated to tsetse density.

Pangolins in south-west Nigeria - current status and prognosis : O. A. Sodeinde & S. R. Adedipe, Oryx, 28(1), 1994, pp 43–50

Despite being officially listed as endangered in Nigeria, pangolins are still hunted in Ogun State, where deforestation has fragmented and reduced their forest habitat. To investigate pangolin status in the state, the authors interviewed hunters, forest workers and market traders selling wild animals or their parts for medicinal use. The authors also counted pangolins stocked by market traders during weekly visits to markets in six towns/villages. Only one of Nigeria's three pangolin species, Manis tricuspis, was encountered frequently. Hunters' reports and evidence of forest destruction suggest that even this species is becoming rare. An estimate of extinction-susceptibility shows that pangolins are at fairly high risk. Creation of sanctuaries for pangolins and other important sympatric vertebrates in forest relicts in south-west Nigeria and the establishment of semicaptive pangolin populations are advocated.

A preliminary survey of Kounounkan Forest, Guinea, West Africa

Biological studies in Guinea have been very patchy, leaving much of the country almost unsurveyed. In 1992 the Fauna and Flora Preservation Society funded a 10-day field visit to Kounounkan, a relict forest at the northern edge of the Upper Guinea Forest Block. The survey found a variety of habitats and high biodiversity, including two vulnerable and one endangered species. Hunting pressure appears to be low and the site is very well suited for the development of further conservation initiatives.

Herbivorous insect species in the tree canopy of a relict South African forest

Abstract. The herbivorous insects on twelve species of evergreen broadleafed trees were repeatedly sampled over a period of 11 months in a small relict forest on the east coast of South Africa. This extraordinarily speciose forest patch has an unusually high proportion of endemic tree species, some of which are extremely rare. The insect herbivore fauna (number of species) seems to be markedly depauperate compared to that reported on native, broadleafed trees from other parts of the world. Some possible reasons for this are discussed. The total number of herbivorous insect species on each tree species was strongly correlated with the local relative abundance of the host plant species. There was no relationship between the total number of insect herbivore species on each tree species and the relative taxonomic isolation of the trees. The proportion of seemingly unique (= specialist) herbivorous insect species (i.e. those that occurred on one tree species only) was greatest on taxonomically isolated trees. A fundamental deficiency in the interpretation of the data in this study, and of many other similar studies that report on the number of insect species on plants, is discussed, namely the lack of clarity on the closeness of the association between individual insect herbivore species and their respective host plants.

Pangolins in south-west Nigeria – current status and prognosis

Despite being officially listed as endangered in Nigeria, pangolins are still hunted in Ogun State, where deforestation has fragmented and reduced their forest habitat. To investigate pangolin status in the state, the authors interviewed hunters, forest workers and market traders selling wild animals or their parts for medicinal use. The authors also counted pangolins stocked by market traders during weekly visits to markets in six towns/villages. Only one of Nigeria's three pangolin species, Manis tricuspis, was encountered frequently. Hunters' reports and evidence of forest destruction suggest that even this species is becoming rare. An estimate of extinction-susceptibility shows that pangolins are at fairly high risk. Creation of sanctuaries for pangolins and other important sympatric vertebrates in forest relicts in south-west Nigeria and the establishment of semicaptive pangolin populations are advocated.

Feeding ecology of Saguinus bicolor bicolor (Callitrichidae: Primates) in a relict forest in Manaus, Brazilian Amazonia.

This study is part of a long-term ecological study of habitat and dietary requirements of the pied bare-face tamarin (Saguinus bicolor bicolor). One group was studied for 11 months in an area of secondary forest in a suburb of Manaus, Amazonas, Brazil. Three main vegetation types occurred inside the group's home range (12 ha): capoeira, older secondary forest and campinarana (white sand forest). The tamarins ate fruits (21 species), flowers (1 species), exudates (4 species), and arthropods (insects and spiders). They spent 14.3% of total activity time seeking and eating animal prey, and 9.9% feeding on plant material, mostly fruits. In general, fruits consumed were ripe, small and succulent. Trees used for feeding were low and had small crown diameters. Three plant species (Protium aracouchinni, Myrcia cf. fallax, and Couma utilis) were used intensively during the three seasons covered by the study period. The concentrated use of 3 fruit species, each for an extended period (one fruiting species per season), provided the tamarins with a regular food supply. Tamarins consumed exudates from holes in the bark of trees of the families Anacardiaceae and Vochysiaceae, as well as gum exuded from seed pods of Mimosaceae. Exudates were exploited during the dry season and at the beginning of the wet season. Group travel was primarily based on routes connecting the fruiting trees exploited, with foraging for animal prey occurring during travel. Tamarins searched for arthropods on trunks, branches and leaves and in trunk holes. The foraging and feeding tactics displayed by S. b. bicolor are closely linked to morphological characteristics (small size and weight, claw-like nails) that allowed access to energy-rich resources (arthropods and plant exudates) in different strata of the vegetation.

Reconstruction of the tree vegetation near a Bronze Age site in Northern Italy based on the analysis of charcoal fragments

We have analyzed the charcoal fragments found during the archaeological excavation at Ca' de Cessi in the Po plain (Mantova, Italy). This place was inhabited during the XIII-th century B.C., a period corresponding to the Late Bronze Age. The identification of the species found in three superimposed layers allowed us to reconstruct the tree vegetation characteristic of the region during this prehistoric period. The identified species are all members of a typical deciduous forest characterized by the predominant presence of Quercus robur, Quercus petraea and Ulmus sp. This association is the same that is found today in the small relict forest areas in the Po plain. This suggests that the climate conditions of this region during the Late Bronze Age were similar to those found today.

Improved identification of Nannomonas infections in tsetse flies from The Gambia

Trypanosomes from 36 midgut infections were isolated in procyclic culture from Glossina morsitans submorsitans and G. palpalis gambiensis in The Gambia. Twenty-eight stocks (78%) were identified using DNA probes specific for: (a) Trypanosoma (Nannomonas) congolense savannah type, (b) T. (N.) congolense riverine-forest type, (c) T. (N.) simiae and (d) Trypanozoon. T. simiae and savannah type T. congolense were found only in G.m. submorsitans while the riverine-forest type T. congolense was restricted to populations of G.p. gambiensis from two isolated areas of relict forest; one Trypanozoon stock was isolated from G.m. submorsitans. T. congolense accounted for only 17% of all Nannomonas infections, as identified by dissection, in G.m. submorsitans. This re-emphasises the importance of differentiating infections below the subgeneric level when estimating challenge to domestic animals. T. simiae could not be distinguished from T. congolense by the arrangement of trypanosomes in the fly proboscis. The 8 stocks which were not identified by DNA probes were separated into two groups on the basis of hybridization with total DNA probes and the cycle of development in experimental tsetse. One group of four isolates, all from G.m. submorsitans, was a new kind of Nannomonas which appeared to be common and widespread in The Gambia. The second group, which was found only in G.p. gambiensis, had a stercorarian cycle of development, maturing in the hindgut, and was morphologically similar to insect forms of the crocodile parasite T. grayi.

Marginal habitats of chimpanzees

(1) This paper aims to define the marginal habitat of the chimpanzee before the advent of man-made bushfires and agriculture. (The numbers in this abstract refer to the sections of the paper). (2) Written inquiries and personal interviews resulted in a map of the geographical range of the chimpanzee. (3) The rainfall data produced by McGrew et al. (1981) are inadequate because they are based upon short-term measurements during the years of the Sahel drought. On a long-term basis, Mt Assirik probably receives more annual rainfall (1200–1300 or even 1400 mm) than Gombe (∼1100–1300 mm?). The driest chimpanzee sites are Falémé-Bafing in Mali (∼1000 mm) and Ugalla in Tanzania (∼800–900 mm). The annual amount of rainfall is, however, not the decisive factor determining the geographical range. (4) The climatically determined belts of natural vegetation in tropical Africa are described and defined. The ecological limit of the chimpanzee runs obliquely through the Isoberlinia soudanien belt, i.e. from the southern part of the dry soudanien belt in Senegal and Mali to the relatively humid soudano-guinéen belt in the Sudan. This lack of fit between vegetation belts and chimpanzee range cannot be explained by the presence or absence of drinking water in the dry season. (5) Before the advent of agriculture, the chimpanzee's geographical range was covered predominantly by rain forests in the equatorial zone, and by dry forests in the soudanien belt. Man has converted these into mosaic landscapes of savannas, woodlands, secondary forests and relict forests. (6) However, before that time, the social herbivores (from elephants to locusts) had a more or less similar mosaic-forming impact, though to a lesser degree. Statements on ecosystems and their fauna should, therefore, be preceded by and based upon an analysis of the status and dynamics of the vegetation. (7) In mosaic landscapes in Guinea and Senegal, chimpanzee population densities at different sites appear not to be correlated with the local floristic composition in terms of percentages of drought-adapted vs humid flora, but they are correlated with the degree of floristic richness and diversity at these sites. In the dry parts of the chimpanzee range in Tanzania the apes depend on a combination of drought-adapted and humid flora. Apparently their need for a diversified diet determines their ecological limit. The oblique course of the range boundary across the soudanien belt can perhaps be explained by increasing floral impoverishment towards the East, owing to man's activities. The surprising absence of chimpanzees East of the Western Rift system must be attributed to ecological barriers and palaeo-conditions. (8) A confusing phenomenon is that drought-adapted types of arboreal vegetation have, in general, higher powers of regeneration than humid (rain forest) types. (9) The comparison between chimpanzees and Bushmen as made by McGrew et al. is inappropriate because the vegetation of Mt Assirik is degraded whereas that of the Kalahari is natural.

Descripcion de un metodo para el estudio de las especies de arboles del valle central de costa rica

A methodology for an inventory of tree species was tested in three forest relicts of the Central Valley, Costa Rica. All three sites are secondary forests, but two (Ciudad Colon, 800 m and San Pedro de Montes de Oca, 1200 m), are of recent regeneration by succession; the oldest (Ochomogo, 1600 m), is an old relict surrounded by cultivated land. Forty families, 97 genera and 144 species of trees were identified from the three forests.

Antecedentia Relictus: The Closed-Cone Pines of California

Despite its title, specifically directed to a California relict forest association, the locale for much of this account is Polynesia. For it is in New Zealand, not California, where a member of these generally undistinguished pines surprisingly has flourished as a com mercial timber tree. It is a significant element in the New Zealand economy today and its success there has even prompted experiments at reintroduction of the improved tree into California.

The Red-billed Curassow

The red-billed curassow, or mutum, Crax blumbachii formerly occurred from southern Bahia to Rio de Janeiro in south-east Brazil, although only a few specimens were ever obtained. Europeans settled this region early, and it was feared that hunting pressure and, later, habitat destruction had brought the species to the verge of extinction when in 1970 Sick discovered a population about 60 km north of Linhares, Espirito Santo, in and near what is now the Reserva de Sooretama. This forest reserve is now the only place where the bird is known. A few may survive in relict forest tracts in southern Bahia, although the last record, a specimen, was collected in 1944. The specimen from eastern Bolivia which Gyldenstolpe assigned to this species was certainly a variant of C. globulosa. On a recent trip to Brazil we found that almost all the forest in north-east Espirito Santo, where this curassow formerly occurred, had been cleared, much of it within the year. Dr Augusto Ruschi (pers. comm.) confirms that the rate of forest destruction, mainly for charcoal, has accelerated markedly in the past decade. The main sources for information on the species are Prince Maximilian of Wied and Sick.

Submerged Relict Forests off Northwest Florida Coast--Paleoenvironmental Significance: ABSTRACT

Submerged Relict Forests off Northwest Florida Coast--Paleoenvironmental Significance: ABSTRACT

Pollen evidence for the protohistoric development of the “big woods” in Minnesota (U.S.A.)

When the presettlement deciduous forest, as described from land-survey notes of 1854–1860, is compared with relict forest stands of today, it is clear that mesic succession has taken place. The “Big Woods”, dominated by Acer and Tilia, has developed from a forest dominated by Ulmus and Quercus with some Tilia and Acer. Two pollen diagrams spanning the past 1,000 years show that this succession was initiated several hundred years before settlement. Three pollen diagrams from the adjacent oak forest suggest a concurrent succession from Quercus savanna, as well as a later increase in mesic elements at the time of settlement. An area that was oak barrens (a type of Quercus savanna) at the time of settlement, now has relict stands of oak forest; the two pollen diagrams from this area suggest the formation of oak forest since settlement. The mesic successions are probably a culmination of a long-term change toward a cooler and moister climate, but a postulated decrease in Indian populations and fires after European contact about 1650 and before settlement could have accelerated the vegetation successions.

Tropical Savanna Vegetation of the Llanos of Colombia

The Llanos Orientales of Colombia are between 3° and 7° lat N, extending as a level plain between 600 and 200 m above sea level, east of the Andes Mountains. The hot tropical climate shows a seasonal pattern of rainfall, divided between one rainy season and one dry season. In the survey of a 45,000—square—mile study area within this llanos region, 10 savanna types were recognized and classified on a floristic basis. Three of these types were floristically distinct, but with the homologous factor of all having relict forests. The other seven savanna types intergraded along a gradient of increasing humidity, and for convenience were divided into dry, humid, and inundable savannas. A great number of species were shared by these last seven types, their distinction being based on the relative dominance of species in the different types. The various theories on the origins of tropical savanna are discussed in the light of this new information on vegetation and that found in a concurrent soil survey. No single factor is believed responsible for savanna formation, but deflection from forest development is considered the result of several adverse factors, with savanna formation accelerated once the process has started.

Some Effects of Livestock Grazing on Ponderosa Pine Forest and Range in Central Washington

Many stories have arisen to describe what the vegetation of the virgin ponderosa pine forest and range was like before white man, his grazing animals, and logging machinery began to harvest the forest land crops. Are the tales of an open, parklike tree overstory with dense stands of grass true ? If so, what has caused the change to the present thin stands of grasses and dense stands of advance tree reproduction ? It is difficult to answer these questions correctly, for practically all of the ponderosa pine forest has been used in some degree by white man. One of the few relicts of virgin ponderosa pine forest and range, which provides an opportunity to investigate the original appearance of the type, is Meeks Table in central Washington. Meeks Table is a 70-acre isolated plateau that has never been grazed by livestock because natural barriers have made it inaccessible. Meeks Table was set aside by the U. S. Forest Service as a Natural Area in 1948. As such it will never be logged or grazed by livestock, but will be maintained in its natural state for observation and study. For comparison, there is Devils Table, a larger plateau covering approximately 2,000 acres four miles southeast of Meeks Table. Devils Table is essentially similar to Meeks Table in geologic origin, elevation, climate, and timber type, but Devils Table has been heavily utilized by livestock during the past 40 years. Both tables are pon-

The Mosquitos of the Kaimosi Forest, Kenya Colony, with special Reference to Yellow Fever

1. The danger of the establishment of yellow fever in certain of the forests of Kenya is pointed out. Kenya has had two recognised cases of the disease in recent years.2. The Kaimosi forest was selected as a suitable area for investigation and the general environmental conditions are described.3. A mosquito survey was undertaken over a period of two years and particular attention was paid to the question of “acrodendrophily” i.e., the preference shown by certain species of mosquitos for life in the tree-tops.4. Five species of mosquitos—Culex nebulosus, Aëdes capensis, A. fraseri, A. deboeri subsp. demeilloni and A. longipalpis breed in high tree-holes; the last, almost entirely so. The many characteristically low breeders include A. aegypti and A. africanus. There is an interesting distinction between the two commoner Megarhines; M. brevipalpis breeds high, M. barbipes, low.5. Four species of mosquitos—A. apicoargenteus, A. fraseri, A. africanus and A. longipalpis were found biting in the tree-tops; the last two being rare in ground catches.6. Forest with a broken canopy proved best for adult catching and the morning was a better time than the (usually overcast) afternoon. Night searches gave negative results. Catches on high tree platforms appeared to be more prolific than those oa the ground.7. The following points of special interest in regard to individual species of mosquitos are summarised below: —(i) Megarhine larvae consume about 20 fourth-stage aegypti larvae a night. Pupal stage lasts on an average for nine days.(ii) Aëdes aegypti breeds commonly in two sites (a) recently felled trees at forest edge; (b) rock pools in rivers in drought periods. Larvae are found a mile or more inside the forest. Breeding of this species has been discovered as high as 6,500 feet.(iii) Aëdes apicoargenteus was the commonest adult. Some specimens survived 55 days in captivity.(iv) Aëdes africanus shows a seasonal incidence, being commonest at the end of the “long rains”. Its favoured breeding places are the buttresses of the tree, Craibia elliottii.(v) In the larval stage, Aëdes capensis is the commonest mosquito.(vi) The characteristic breeding place of Theobaldia fraseri contained 79 parts of oxidisable matter per 100,000 of water.8. Probably at least two trees per acre have rot holes with larvae and about 14 per cent, of the Dracaena plants are infested. Holes in shaded granite boulders are another common source of sylvan mosquitos.9. Surveys of adjacent forest areas at different altitudes revealed striking changes in the mosquito fauna. Aëdes pulchrithorax is the prevalent species at the 6,500 foot level; A. kapretwae at the 8,500 foot; whilst in general, A. africanus, A. aegypti and A. bambusae appear to be widespread.10. A study of the lists of mammals, trees and mosquitos indicates that the relict forest of Kaimosi contains numerous “western” species which are not found elsewhere so far to the east.11. Immunity tests performed at the Yellow Fever Research Institute, Entebbe, demonstrated the absence of yellow fever in man and monkeys at Kaimosi. The monkeys show, however, immunity to Semliki forest virus and either Japanese B or St. Louis encephalitis virus.12. The human inhabitants suffer from malaria and onchocerciasis (the latter carried by Simulium neavei) and the monkeys and fruit bats are infected with species of Plasmodium.13. The Kaimosi forest from every standpoint (including meteorological) is suitable for the establishment of jungle yellow fever and possible measures of control ate briefly suggested.14. Short descriptions of new species, etc., of mosquitos are given in the Appendix

Ecological Composition of Pulpwood Forests in Northwestern Maine

Within the State of Maine are few, if any, relicts of the original northeastern coniferous forest. Extensive areas of forest land are covered with second-growth forest, the main source of pulpwood for the local papermills. Silvicultural considerations have had little weight in determining the management of these forests in the past. Demand for and accessibility of timber have regulated the extent of each year's cut. Modern methods of operation, particularly clear-cutting, suggest the future value and usefulness of silvical and ecological information pertinent to tlhe nature of these second-growth forest commuinities. Sound silvicultural practices can be initiated and applied successfully only as ecological and silvical information accumulates. The Swain and Reed Lumber Company of Roxbury, Maine, provided special facilities in the summer of 1940 which made possible an ecological survey of the pulpwood forests in the general vicinity of the watershed of Swift River, a tributary of the Androscoggin River, located in northern Oxford County, Maine. After reconnaissance, several stands were selected as representative of the pulpwood forests of the region, and these were studied intensively on a phytosociological basis. This is a report on the findings of the study with conclusions drawn from the data obtained.