scholarly journals Effects of habitat disturbance and hunting on the density and the biomass of the endemic Hose’s leaf monkey Presbytis hosei (Thomas, 1889) (Mammalia: Primates: Cercopithecidae) in east Borneo

2004 ◽  
Vol 73 (4) ◽  
pp. 283-291 ◽  
Author(s):  
Vincent Nijman

Hose’s leaf monkey Presbytis hosei is endemic to Borneo and occurs only in tall forest. In recent decades Borneo has lost a large part of its forest cover, mostly in low-lying coastal regions. Large intact tracts of forest remain in the interior, but these are by and large inhabited by tribes that subsist in part by hunting. The combined effects of habitat disturbance and hunting on the densities and biomass of Hose’s leaf monkey were studied in Kayan Mentarang National Park in Borneo’s far interior. Over four months, data on densities and hunting were collected by transect walks in four forest types. Hose’s leaf monkeys were hunted to deter crop-raiding, for their meat, and to obtain bezoar stones (visceral secretions used in traditional medicine). Hose’s leaf monkeys occurred in single male groups of 7-8 individuals in densities from 0.8 to 2.3 groups km-2. Densities of Hose’s leaf monkeys were positively correlated with certain vegetation characteristics, e.g. tree height and height of first bough, and negatively correlated with distance to the nearest village. Biomass of Hose’s leaf monkeys declined considerably as a result of habitat disturbance and hunting from 92 kg km-2 in primary hill forest inside the reserve to 38 kg km-2 in old secondary forest and 31 kg km-2 in young secondary forest near villages. A review of the few studies conducted on the effects of habitat disturbance and hunting on Hose’s leaf monkeys reveal inconsistent trends in biomass and density responses.

2018 ◽  
Vol 10 (12) ◽  
pp. 1980 ◽  
Author(s):  
Xavier Haro-Carrión ◽  
Jane Southworth

Understanding forest cover changes is especially important in highly threatened and understudied tropical dry forest landscapes. This research uses Landsat images and a Random Forest classifier (RF) to map old-growth, secondary, and plantation forests and to evaluate changes in their coverage in Ecuador. We used 46 Landsat-derived predictors from the dry and wet seasons to map these forest types and to evaluate the importance of having seasonal variables in classifications. Initial RF models grouped old-growth and secondary forest as a single class because of a lack of secondary forest training data. The model accuracy was improved slightly from 92.8% for the wet season and 94.6% for the dry season to 95% overall by including variables from both seasons. Derived land cover maps indicate that the remaining forest in the landscape occurs mostly along the coastline in a matrix of pastureland, with less than 10% of the landscape covered by plantation forests. To obtain secondary forest training data and evaluate changes in forest cover, we conducted a change analysis between the 1990 and 2015 images. The results indicated that half of the forests present in 1990 were cleared during the 25-year study period and highlighted areas of forest regrowth. We used these areas to extract secondary forest training data and then re-classified the landscape with secondary forest as a class. Classification accuracies decreased with more forest classes, but having data from both seasons resulted in higher accuracy (87.9%) compared to having data from only the wet (85.8%) or dry (82.9%) seasons. The produced cover maps classified the majority of previously identified forest areas as secondary, but these areas likely correspond to forest regrowth and to degraded forests that structurally resemble secondary forests. Among the few areas classified as old-growth forests are known reserves. This research provides evidence of the importance of using bi-seasonal Landsat data to classify forest types and contributes to understanding changes in forest cover of tropical dry forests.


Author(s):  
Abdul Rosyid

Tarsius lariang, also called tangkasi is one of the endemic animals which is found in Lore Lindu National Park (LLNP). The threat to the tarsius population are the limitation of the distribution area, the escalation of forests exploitation, and hunting. People around the forest tend to think the tangkasi as a pest which eats cultivated plants. Therefore, population and habitat research is important. The purpose of this study is to estimate the demographic parameters and identify the characteristics of the habitat of the tangkasi, so that it can be known that the habitat component is important for the existence of the tangkasi in LLNP. The results of this study indicate the density of individual tangkasi across the LLNP region is 95.55 individuals per km². Individual density on Primary Dryland Forest Cover (PDFC) was 80.21 individuals per km² and in Dryland Secondary Forest (DSF) cover was 218.29 individuals per km², which still in normal level. The population density of tangkasi groups in the LLNP area is 35 groups per km², for the PDFC 32 and for the DSF of 54 groups per km². The total population of tangkasi based on age structure located in the research area of LLNP, PDFC, and DSF shows that the age of the juvenile is very low compared to the sub-adult age classes. It shows that tangkasi population is decreasing (regressive population). The preferred habitat of the tangkasi is the type of Dryland Secondary Forest (SDF) with a very steep slope of < 45% and altitude between 1301 and 1800 m asl.


1992 ◽  
Vol 22 (1) ◽  
pp. 37-45 ◽  
Author(s):  
Roy A. Renkin ◽  
Don G. Despain

The occurrence and behavior of lightning-caused fires in Yellowstone National Park were summarized for 17 years (1972–1988) during a prescribed natural fire program. Both ignition (occurrence) and spread (stand replacing fire activity) of fires were strongly influenced by fuel moisture and forest cover type. Fuel moisture estimates of 13% for large (>7.6 cm) dead and downed fuels indicated a threshold below which proportionately more fire starts and increased stand replacing fire activity were observed. During periods of suitable fuel moisture conditions, fire occurrence and activity were significantly greater than expected in old-growth, mixed-canopy lodgepole pine (Pinuscontorta Dougl. var. latifolia) and Engelmann spruce–subalpine fir (Piceaengelmannii Parry–Abieslasiocarpa (Hook.) Nutt.) forest types, and significantly less than expected in the successional lodgepole pine forest types. During periods of extended low fuel moisture conditions (drought), sustained high winds significantly reduced the influence of forest cover type on stand replacing fire activity. These extreme weather conditions were observed during the later stages of the 1988 fire season, and to a lesser extent, for a short duration during the 1981 fire season. The Douglas-fir (Pseudotsugamenziesii (Mirb.) Franco) forest type typically supported little stand replacing fire activity, even though a preponderance of fire starts was observed.


2019 ◽  
pp. 68-72
Author(s):  
E. A. Volkova

A monograph “Vegetation and biotopes of the “Narochansky” National Park was published in Minsk, Belarus in 2017, edited by A. V. Pugachevsky (Grummo et al., 2017). It includes the Map of terrestrial vegetation (S. 1 : 60 000) and the Map of biotopes (S. 1 : 60 000). Some small-scale maps such as the Map of changes in forest cover of the “Narochansky” National Park for the period 1985–2016, the Map of forest loss in the “Narochansky” National Park for the period 1985–2016 and a series of inventory and analytical maps on the basin of the Naroch Lake are given. This monograph can be considered as a small regional Atlas with detailed explanatory texts to the maps. It presents the experience on vegetation mapping accumulated in the Laboratory of Geobotany and Vegetation mapping of the Institute of Experimental Botany of the National Academy of Sciences of Belarus. Despite some critical comments, mainly concerning the biotope map, this publication of Belarusian geobotanists deserves an approval. They received the full answers to the questions posed: “What do we protect?” and “What is a current state of the vegetation of the National Park and the main trends of its dynamics? Cartographic design is made at a high level; the maps have both scientific and practical importance in the planning of environmental and economic activities.


Land ◽  
2021 ◽  
Vol 10 (8) ◽  
pp. 817
Author(s):  
Marina Palmero-Iniesta ◽  
Josep Maria Espelta ◽  
Mario Padial-Iglesias ◽  
Òscar Gonzàlez-Guerrero ◽  
Lluís Pesquer ◽  
...  

Farmland abandonment has been a widespread land-use change in the Iberian Peninsula since the second half of the 20th century, leading to the establishment of secondary forests across the region. In this study, we aimed to address changes in the recent (1985–2014) emergence patterns of these forests and examine how environmental factors affected their growth by considering differences in leaf-habit types. We used a combination of Landsat-derived land-cover maps and aboveground biomass (AGB) maps from the European Space Agency to assess the secondary forest establishment and growth, respectively, in the study region. We also obtained a set of topographic, climatic and landscape variables from diverse GIS layers and used them for determining changes over time in the environmental drivers of forest establishment and AGB using general linear models. The results highlight that secondary forest cover was still increasing in the Iberian Peninsula at a rate above the European average. Yet, they also indicate a directional change in the emergence of secondary forests towards lower and less steep regions with higher water availability (mean rainfall and SPEI) and less forest cover but are subjected to greater drought events. In addition, these environmental factors differentially affect the growth of forests with different leaf-habit types: i.e., needleleaf secondary forests being less favoured by high temperature and precipitation, and broadleaf deciduous forests being most negatively affected by drought. Finally, these spatial patterns of forest emergence and the contrasting responses of forest leaf-habits to environmental factors explained the major development of broadleaf evergreen compared to broadleaf deciduous forests and, especially, needleleaf secondary forests. These results will improve the knowledge of forest dynamics that have occurred in the Iberian Peninsula in recent decades and provide an essential tool for understanding the potential effects of climate warming on secondary forest growth.


2002 ◽  
Vol 46 (1) ◽  
Author(s):  
Dietrich Schmidt-Vogt

AbstractManagement of secondary tropical forests: a new perspective for sustainable use of forests in Asia. The decline of primary forests in the tropics is leading to a reassessment of the role secondary forests might play within the context of tropical forest management. Recent research has shown that secondary forests in the tropics can be both rich in species and complex in terms of stand structure. There is, moreover, a growing recognition of the importance of secondary forests for traditional subsistence economies in the tropics and of their economic potential for land use systems in the future. Management of secondary forests in Asia as an alternative to the extraction of timber from primary forests but also as one among other options to intensify traditional land use systems has a potential for the future especially because of the existence of vast tracts of valuable secondary forest cover, and because of the store of traditional knowledge that can still be found in tropical Asia.


2003 ◽  
Vol 81 (2) ◽  
pp. 266-271 ◽  
Author(s):  
Jerry O Wolff ◽  
Toni Van Horn

Animal behavior is often optimized as a trade-off between survival and reproduction. During the breeding season, mammals tend to maximize their reproductive effort within the constraints of predation pressure. When predation pressure is reduced, greater effort can be allocated to reproductive behavior and less to vigilance and predator avoidance. The objective of this study was to test the hypothesis that elk, Cervus elaphus, in Yellowstone National Park (YNP), with predators, would spend more time in vigilance and risk-avoidance behavior than would elk in Rocky Mountain National Park (RMNP), a predator-free environment. We further predicted that elk at Mammoth Hot Springs (MAM) in YNP would behave similarly to those at RMNP because predators were absent in that area of the park. Cow elk in YNP spent more time in vigilance and less in foraging during activity periods than did cows in RMNP or MAM. Also, elk in YNP retreated to forest cover during the midday inactive period, whereas elk in RMNP and MAM remained in open habitat. Vigilance was not correlated with group size at either site. Cows with calves spent more time in vigilance and less in foraging than did cows without calves in RMNP and YNP. Bull elk spent most of their time in courtship at all sites, but foraged more at RMNP than in YNP or MAM. Mean harem sizes were similar among the three sites: 17.0 in RMNP, 15.7 in YNP, and 19.0 in MAM. The proportion of cows with calves was significantly lower in the area with predators, YNP (0.10), than in the predator-free areas (0.24 in RMNP and 0.37 in MAM), probably because of greater calf mortality in YNP. Elk in YNP behaved in accordance with a predation risk, whereas those in RMNP and MAM showed less vigilance behavior.


2017 ◽  
Vol 130 (4) ◽  
pp. 281 ◽  
Author(s):  
David Hamer

Bears (Ursus spp.) in North America eat the seeds of several pines (Pinus spp.), including Limber Pine (P. flexilis E. James). Information on use of Limber Pine in Canada is limited to a report of three bear scats containing pine seeds found in Limber Pine stands of southwestern Alberta. After my preliminary fieldwork in Banff National Park revealed that bears were eating seeds of Limber Pine there, I conducted a field study in 2014–2015 to assess this use. Because bears typically obtain pine seeds from cone caches (middens) made by Red Squirrels (Tamiasciurus hudsonicus), I described the abundance, habitat characteristics, and use by bears of Red Squirrel middens in and adjacent to Limber Pine stands at six study sites. On Bow River escarpments, I found abundant Limber Pines (basal area 1–9 m2/ha) and middens (0.8 middens/ha, standard deviation [SD] 0.2). Of 24 middens, 13 (54%) had been excavated by bears, and three bear scats composed of pine seeds were found beside middens. Although Limber Pines occurred on steep, xeric, windswept slopes (mean 28°, SD 3), middens occurred on moderate slopes (mean 12°, SD 3) in escarpment gullies and at the toe of slopes in forests of other species, particularly Douglas-fir (Pseudotsuga menziesii). At the five other study sites, I found little or no use of Limber Pine seeds by bears, suggesting that Limber Pine habitat may be little used by bears unless the pines are interspersed with (non-Limber Pine) habitat with greater forest cover and less-steep slopes where squirrels establish middens. These observations provide managers with an additional piece of information regarding potential drivers of bear activity in the human-dominated landscape of Banff National Park’s lower Bow Valley.


2012 ◽  
Vol 19 (3) ◽  
pp. 115-123
Author(s):  
YANTO SANTOSA ◽  
TAQIUDDIN ◽  
ABDUL HARIS MUSTARI ◽  
DEDE AULIA RAHMAN

2015 ◽  
Vol 39 (3) ◽  
pp. 205-215 ◽  
Author(s):  
Alexander Christian Vibrans ◽  
Paolo Moser ◽  
Laio Zimermann Oliveira ◽  
João Paulo de Maçaneiro

Total tree height (h) is often difficult to measure in natural forests. Regression models based on easily accessed variables like DBH (d) can be an alternative, since their assumptions are validated. The aims of this study are to: (i) calibrate specific and generic h-d models for three forest types (Seasonal Deciduous Forest, DEC; Mixed Ombrophilous Forest, MIX; and Dense Rainforest, DEN) in Santa Catarina state testing the regression assumptions and evaluating model quality; (ii) verify different h-d relationship between forest types. The dataset (1,766 measured tree h and 3,150 estimated h) was collected by Santa Catarina Forest and Floristic Inventory (IFFSC) in 418 systematically located sample plots. Models were calibrated for two datasets, one containing hypsometer measurements, the other h estimations made by field crews. Specific models were calibrated for species with at least 30 sampled trees. Residual normality, randomness and heteroskedasticity were evaluated by analytical methods. Confidence bands were generated by the Working-Hotelling method; z test for means was applied to compare models based on the two databases. The statistical parameters such as corrected Akaike Information Criterion provided evidences that logarithmic models were better adjusted to the data. Both datasets were statistically different for DEN and MIX. Differences in h-d relationships were found between forest types. The use of calibrated h-d models is an alternative for studying the relationships between these variables and to assess vertical structure patterns of forest communities, when h measurements are not feasible, although, for situations that more accurate h values are needed, they will not always provide reliable predictions.


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