Frugivory and the fate of dispersed and non-dispersed seeds of six African tree species

1996 ◽  
Vol 12 (4) ◽  
pp. 491-504 ◽  
Author(s):  
Colin A. Chapman ◽  
Lauren J. Chapman
Keyword(s):  
Tree Species ◽  
National Park ◽  
Seedling Recruitment ◽  
Seedling Survival ◽  
Kibale National Park ◽  
Lower Probability ◽  
Foraging Activity ◽  
Seedling Density ◽  
Trade Off ◽  
The Relationship

ABSTRACTThe relationship between seedling recruitment (under and away from parent trees) and the behaviour of seed dispersers and predators, was explored in a three-year study in Kibale National Park, Uganda. On the basis of 1261 hours of observation, the foraging activity of the diurnal frugivores which fed on fruit from six tree species was quantified. The fate of dispersed and non-dispersed seeds and seedlings was examined experimentally. The findings suggest that a trade-off exists between factors that promote seedling growth in areas with high seedling density and factors that promote dispersal by frugivores. For example, dispersal ofMimusops bagshaweiincreases both seed and seedling survival; seeds placed away from adult conspecifics had a 8% lower probability of disappearing than seeds placed under adults and seedlings away from adults had a 30% greater probability of surviving than seedlings grown under adults. In contrast, forUvariopsis congensis, dispersed seeds had a 56% greater probability of disappearing than seeds directly under a parent tree, while the survival of dispersed and non-dispersed seedlings was similar. Non-dispersed seed and seedling disappearance were correlated with the percentage of the fruit crop removed from focal trees, suggesting that the ability to survive under an adult maybe related to other aspects of the tree's life history.

Landscape-scale heterogeneity in lodgepole pine serotiny

1994 ◽  
Vol 24 (5) ◽  
pp. 897-903 ◽  
Author(s):  
Daniel B. Tinker ◽  
William H. Romme ◽  
William W. Hargrove ◽  
Robert H. Gardner ◽  
Monica G. Turner
Keyword(s):  
National Park ◽  
Lodgepole Pine ◽  
Morphological Characteristics ◽  
Landscape Scale ◽  
Acute Angle ◽  
Seedling Density ◽  
Postfire Regeneration ◽  
Lodgepole Pines ◽  
The Relationship ◽  
Landscape Level

A 1992 study of serotiny in lodgepole pine (Pinuscontorta Dougl. ex Loud. var. latifolia Engelm.) in Yellowstone National Park asked four questions: (i) are there morphological characteristics that can be used to estimate pre-fire proportion of serotinous trees in forests that burned in 1988?; (ii) at what spatial scale does percent serotinous trees vary across the landscape?; (iii) which environmental factors are correlated with serotiny?; and (iv) what is the relationship between prefire serotiny and postfire lodgepole pine seedling density? We first sampled cone characteristics in serotinous and nonserotinous trees along four 2950-m transects in unburned forests, and examined burned trees nearby. Results indicated that asymmetrical cones and an acute angle of cone attachment to the branch were reliable indicators of serotiny even in burned trees. We then sampled nine patches of lodgepole pine forest that had burned in 1988, and varied in size from 1–3600 ha. We sampled serotiny at varying intervals along two perpendicular transects that crossed in the center of each patch. At each sample point, the 12 nearest canopy lodgepole pines were classified as serotinous or nonserotinous. We concluded that the percentage of serotinous trees is most variable at intermediate scales of 1–10 km, and is relatively homogeneous at both fine scales (<1 km) and at very broad scales (tens of kilometers). Percent serotiny was generally more variable and greater at low to middle elevations. Prefire density of serotinous trees was a more important predictor of postfire seedling density than aspect, slope, or soil type. These findings have important implications for landscape-level patterns in postfire regeneration of lodgepole pine.

The savanna tree Acacia polyacantha facilitates the establishment of riparian forests in Serengeti National Park, Tanzania

2009 ◽  
Vol 25 (1) ◽  
pp. 31-40 ◽  
Author(s):  
Gregory J. Sharam ◽  
A. R. E. Sinclair ◽  
Roy Turkington ◽  
Aerin L. Jacob
Keyword(s):  
Tree Species ◽  
Natural Regeneration ◽  
National Park ◽  
Seedling Survival ◽  
Forest Tree ◽  
Riparian Forests ◽  
Forest Trees ◽  
Grass Cover ◽  
Serengeti National Park ◽  
Acacia Polyacantha

Abstract:Forests are being converted to grasslands and croplands across Africa and natural regeneration of forests is typically poor. In Serengeti National Park, Tanzania, the savanna tree species Acacia polyacantha established in riparian grasslands and forest trees subsequently established within these stands. We examined the conditions for establishment of: (1) A. polyacantha and (2) riparian (non-Acacia) forests. Fire was excluded from three grassland areas for 5 y allowing A. polyacantha to establish during 1999 when dry-season rainfall was high. The seedlings of forest tree species did not establish in grasslands, but were found in large A. polyacantha stands (> 0.3 ha) with reduced grass cover (< 10%), higher cover of herbs (> 80%) and thorny shrubs (> 90%). Seeding survival was high in large stands (0.87 y−1), but declined in artificial canopy gaps due to the ingrowth of grasses (0.21 y−1) and subsequent fires (0.07 y−1). Shrub removal also reduced seedling survival (0.46 y−1) due to browsing by antelope. We propose that: (1) A. polyacantha establishes in pulses perhaps as infrequently as twice per century, and (2) riparian forests in Serengeti have established via facilitation under larger stands where shade excludes grass, and therefore fires and thorny shrubs exclude browsers.

Regeneration from seed of six tree species in the interior cedar-hemlock forests of British Columbia as affected by substrate and canopy gap position

1998 ◽  
Vol 28 (9) ◽  
pp. 1352-1364 ◽  
Author(s):  
Elaine F Wright ◽  
K Dave Coates ◽  
Paula Bartemucci
Keyword(s):  
Tree Species ◽  
Shade Tolerance ◽  
Community Dynamics ◽  
Seedling Survival ◽  
Tree Regeneration ◽  
Canopy Gap ◽  
Abies Lasiocarpa ◽  
Differential Survival ◽  
Trade Off ◽  
Light Levels

Canopy gap size can play a major role in determining composition of tree regeneration after disturbance. The effect of different positions within gaps and within the intact forest has received less study. We seeded six tree species onto two substrates (organic and undisturbed moss) in three positions along a north-south gradient within eight replicate 600-m2 canopy gaps and in the intact forest south of each gap (the gap positions), in 1995 and 1996. Emergence of all species was strongly affected by gap position, seedbed substrate, and year, but there was little evidence of partitioning by gap position among the species. Average emergence was higher in the shady southern position in gaps and within the intact forest and significantly higher on organic than undisturbed moss substrates (with the exception of Abies lasiocarpa (Hook.) Nutt., which showed no preference for seedbed). Seedling survival was greatest for all species in the south end of the gap, where soil moisture remained highest and light levels of approximately 20% full sun were adequate for survival. A species trade-off was observed in the understory of the intact forest, where differential survival based on shade-tolerance ranking occurred. To predict regeneration success in these forests, for either silvicultural purposes or to permit a better understanding of community dynamics and succession, it is important to consider the influence of position inside and outside of gaps and the nature of the seedbed substrate.

scholarly journals Vegetation Dynamics in Treeline Ecotone of Langtang National Park, Central Nepal

1970 ◽  
Vol 11 ◽  
pp. 107-114 ◽  
Author(s):  
NP Gaire ◽  
YR Dhakal ◽  
HC Lekhak ◽  
DR Bhuju ◽  
SK Shah
Keyword(s):  
Tree Species ◽  
National Park ◽  
Basal Area ◽  
Anthropogenic Pressure ◽  
Climatic Warming ◽  
Seedling Density ◽  
Treeline Ecotone ◽  
Central Nepal ◽  
Abies Spectabilis ◽  
The Impact

A study was carried out at the treeline ecotone (3,730m-3,950m asl) of Langtang National Park in central Nepal with an aim to document the impact of climatic warming on ecological chracteristics. Three sampling sites were selected at Chaurikharka and Lauribina, where no serious anthropogenic pressure was noticed. The nearest meteorological station has records of climatic warming in recent years. Six tree species and three shrub species belonging to seven families were enumerated from the study plots. The average basal area for tree species was found to be 20.56 m2 per ha while average tree density was found to be 734 trees per ha with Abies spectabilis as dominant species. The mean DBH (diameter at breast height) of tree species was found to be 15.8 cm (max. 115.5cm). Density of dead trees accounted 2 no. per ha with basal area 0.195m2 per ha. Average sapling and seedling density of tree species per ha was observed to be 1,590 and 831 respectively. The average sapling and seedling density of A. spectabilis was 255 and 350 per ha respectively. Similarly, average shrub density (per ha) for the area was found to be 9,609 no/ha. The stand character showed that there was high level of recruitment of A. spectabilis in the recent years. The presence of sapling and seedling of A. spectabilis at higher altitude showing linear relationship with canopy coverage indicated prospects for a gradual and upward shift of A. spectabilis with increased temperature. Key words: Abies spectabilis; regeneration; climate change; DBH DOI: 10.3126/njst.v11i0.4132Nepal Journal of Science and Technology 11 (2010) 107-114

A decade of canopy-tree seedling survival and growth in two Bornean rain forests: persistence and recovery from suppression

2002 ◽  
Vol 18 (5) ◽  
pp. 645-658 ◽  
Author(s):  
Lisa J. Delissio ◽  
Richard B. Primack ◽  
Pamela Hall ◽  
H. S. Lee
Keyword(s):  
Tree Species ◽  
National Park ◽  
Seedling Survival ◽  
High Growth ◽  
Tree Seedlings ◽  
Gap Formation ◽  
Rain Forests ◽  
Tree Seedling ◽  
Dipterocarp Forests ◽  
Census Interval

The population dynamics of 8500 shade-tolerant tree seedlings of 13 tree species were followed for 10 years at rain forests in Lambir Hills National Park and Bako National Park, Malaysian Borneo. Since these dipterocarp forests have lower rates of canopy gap formation than do rain forests elsewhere, tree seedling biology was predicted to differ. Approximately 50% of seedlings present in 1986 were still alive in 1996. Seven out of thirteen had seedling populations composed predominantly of individuals that were at least 10 years old. These seedlings can undergo alternating periods of relatively rapid and slow growth. Many seedlings that grew rapidly in the first census interval survived through a period of suppression in the second census interval, and conversely many seedlings with a history of suppression had exceptionally high growth in the final census interval. Seedlings of South-East Asian forest tree species are long-lived and appear to be adapted to long periods of suppression in the understorey.

WILD ROBUSTA COFFEE (COFFEA CANEPHORA FROEHNER) SEEDLING RECRUITMENT AND SURVIVAL IN KIBALE NATIONAL PARK, UGANDA

1998 ◽  
Vol 46 (3) ◽  
pp. 189-198
Author(s):  
Hannington Oryem-Origa ◽  
MichaelJ.S. Magambo ◽  
John Kasenene M.
Keyword(s):  
Mortality Rate ◽  
National Park ◽  
Seedling Recruitment ◽  
Coffea Canephora ◽  
Kibale National Park ◽  
Ground Vegetation ◽  
Botanic Garden ◽  
Mortality Factors ◽  
Seedling Mortality ◽  
Robusta Coffee

Survival of wild robusta coffee (Coffea canephora) seedlings on the forest understorey in Kibale National Park was monitored and analyzed in response to a number of mortality factors, such as fungal diseases, herbivory, desiccation, trampling, and litter of other plant species. A comparison was made with wild coffee seedlings germinated in the laboratory and transplanted in the Botanic Garden under two light conditions. There was a general decrease in the number of coffee seedlings with time under all treatments and in all sites. Seedling mortality rate was initially rapid but later slowed down to a steady rate. Seedling mortality was highest on plots with intact ground vegetation cover and lowest on plots without ground vegetation and leaf litter. In the Botanic Garden, seedlings grown on plots partially illuminated had a much lower mortality rate and longer half-life than those grown on fully illuminated plots. Fungal infection affected the largest percentage of coffee seedlings, followed by herbivory. Trampling had the least effect on coffee seedlings. The effects of all mortality factors on coffee seedlings decreased with age under all treatments.

Density- and distance-dependent seedling survival in a ballistically dispersed subtropical tree species Philenoptera sutherlandii

2008 ◽  
Vol 24 (1) ◽  
pp. 1-8 ◽  
Author(s):  
S. Boudreau ◽  
M. J. Lawes
Keyword(s):  
Tree Species ◽  
Seedling Survival ◽  
Positive Density ◽  
Seedling Density ◽  
Predator Satiation ◽  
Term Survival ◽  
Recruitment Curve ◽  
Parent Tree ◽  
Adult Trees ◽  
Ballistic Dispersal

Abstract:We examine the density- and distance-dependent seedling survival of Philenoptera sutherlandii, a common pod-bearing and dehiscent legume (Fabaceae) in Ongoye Forest, South Africa. Short-range ballistic dispersal causes seed to fall beneath the parent tree, where density- or distance-dependent mortality effects are expected to be concentrated. One hundred and eighty marked seedlings were monitored in a 0.5-ha plot containing 30 adults. Our survival data do not support the escape hypothesis. Predation levels declined with increasing seedling density (positive density-dependent survival), but seedling survival after 15 mo was not distance-dependent. Nevertheless, a unimodal (hump-shaped) recruitment curve, typically associated with decreasing seedling density and increasing seedling survival with distance, was observed. In the context of ballistic dispersal, this recruitment curve may indicate a hump-shaped dispersal kernel with predator satiation at high seedling densities near a parent tree. This recruitment curve likely arises because generalized insect seedling predators while attracted to the adult trees also tend to forage farther away. Short dispersal distances, in turn generate the high densities needed to satiate seed and seedling predators. Predator satiation results in long-term survival rates in P. sutherlandii similar to more widely dispersed and less common tree species.

Post-fire Seedling Recruitment in Coastal Heathland in Relation to Regeneration Strategy and Habitat

1998 ◽  
Vol 46 (1) ◽  
pp. 75 ◽  
Author(s):  
Andrew S. Benwell
Keyword(s):  
Growth Rate ◽  
Shoot Growth ◽  
Seedling Recruitment ◽  
Seedling Survival ◽  
Regeneration Strategy ◽  
Seedling Density ◽  
Fire Response ◽  
Ecotypic Variation ◽  
North Eastern ◽  
Shoot Growth Rate

Post-fire seedling recruitment was studied at six heathland sites near Evans Head, north-eastern NSW, in a range of habitats from dry to wet sand-heath. Species fire responses were recorded and seedling density, seedling survival and seedling shoot-growth rate were monitored for 3 years. There were marked differences in total seedling density and survivorship in different habitats, caused by several possible factors. Obligate seeders and facultative resprouters were found to have overlapping yet broadly distinctive patterns of seedling recruitment behaviour. Facultative resprouters as a group had significantly lower levels of seedling density and survival than obligate seeders. Six species exhibited ecotypic variation in mode of regeneration, five accompanied by marked changes in seedling density. Patterns of seedling recruitment behaviour in relation to fire response and habitat were consistent with the theory that resprouting is a stress-tolerant regeneration strategy and that for a given species regeneration strategy is linked with habitat quality.

‘Nature Has Its Own Soul and Speaks Its Own Language’

2010 ◽  
Vol 19 (2) ◽  
pp. 62-73
Author(s):  
Helena Ruotsala
Keyword(s):  
National Park ◽  
Tourism Industry ◽  
Reindeer Herding ◽  
Nature Protection ◽  
Economic Interests ◽  
Finnish Lapland ◽  
The People ◽  
Heated Debate ◽  
The 1960S ◽  
The Relationship

Nature and environment are important for the people earning their living from natural sources of livelihood. This article concentrates on the local perspective of the landscape in the Pallastunturi Fells, which are situated in Pallas-Ylläs National Park in Finnish Lapland. The Fells are both important pastures for reindeer and an old tourism area. The Pallastunturi Tourist Hotel is situated inside the national park because the hotel was built before the park was established 1938. Until the 1960s, the relationship between tourism and reindeer herding had been harmonious because the tourism activities did not disturb the reindeer herding, but offered instead ways to earn money by transporting the tourists from the main road to the hotel, which had been previously without any road connections. During recent years, tourism has been developed as the main source of livelihood in Lapland and huge investments have been made in several parts of Lapland. One example of this type of investment is the plan to replace the old Pallas Tourist hotel, which was built in 1948, with a newer and bigger one. It means that the state will allow a private enterprise to build more infrastructures for tourism inside a national park where nature should be protected and this has sparked a heated debate. Those who oppose the project criticise this proposal as the amendment of a law designed to promote the economic interests of one private tourism enterprise. The project's supporters claim that the needs of the tourism industry and nature protection can both be promoted and that it is important to develop a tourist centre which is already situated within the national park. This article is an attempt to try to shed light on why the local people are so loudly resisting the plans by a private tourism enterprise to touch the national park. It is based on my fieldwork among reindeer herding families in the area.

Gebirgswaldpflege – es kommt auf den Standort an | Mountain silviculture – it all depends on the site

2001 ◽  
Vol 152 (5) ◽  
pp. 169-176 ◽  
Author(s):  
Monika Frehner
Keyword(s):  
Nature Conservation ◽  
Low Temperature ◽  
Tree Species ◽  
Forest Stand ◽  
Ground Vegetation ◽  
Mountain Forests ◽  
Research Projects ◽  
Snow Mould ◽  
The Relationship ◽  
Protection Forests

The article shows that knowledge of the site of a particular forest stand, together with research results and experience, can provide information that is important for the cultivation of mountain forests, including knowledge of the composition of the tree species and the structure and growth capacity of natural forest. Furthermore, certain sites can, thus, be characterized by factors that influence restocking, such as snow mould,lush ground vegetation or low temperature. The guidelines«minimale Pflegemassnahmen» – «Minimal tending of protection forests» (WASSER und FREHNER, 1996) are based on this principle. For individual sites, warnings about natural dangers such as rock fall or statements concerning nature conservation can be made (e.g., the occurrence of tree species, suitability as a biotope for Capercaille). In conclusion, two research projects on the relationship between site and natural dangers will be presented.

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