scholarly journals The line transect method for estimating densities of large mammals in a tropical deciduous forest: An evaluation of models and field experiments

1995 ◽  
Vol 20 (2) ◽  
pp. 273-287 ◽  
Author(s):  
K Surendra Varman ◽  
R Sukumar
2014 ◽  
Vol 62 (4) ◽  
pp. 1433 ◽  
Author(s):  
Malinalli Cortés-Marcial ◽  
Miguel Briones-Salas

<p>The use of camera traps and mammal track search are complementary methods to monitoring species of which is not well documented their natural history, as in the case of medium and large mammals. To ensure its conservation and good management, it is necessary to generate information about the structure of the community and their populations. The objective of the present study was to estimate the diversity, relative abundance and activity patterns of medium and large mammals in a tropical deciduous forest located in the Isthmus of Tehuantepec, Oaxaca, Mexico. Samplings were conducted in three month intervals, from September 2011 to May 2013. We used photographic-sampling and track search, two complementary sampling methods. For photographic-sampling, 12 camera traps were placed covering an area of 60km<sup>2</sup>, while for the tracks search a monthly tour of four line-transect surveys of three kilometers length each was undertaken. We obtained a total of 344 pictures with 5 292 trap-days total sampling effort; in addition, 187 track records in a total of 144km. With both methods we registered 21 species of mammals, in 13 families and seven orders, and five species resulted in new records to the area. The diversity index of Shannon-Wiener obtained with the method of tracks was H´=2.41, while the most abundant species were <em>Urocyon cinereoargenteus</em> (IAR=0.23) and <em>Pecari tajacu</em> (IAR=0.20). By the method of trap the most abundant species were <em>P. tajacu</em> (IAR=2.62) and <em>Nasua narica</em> (IAR=1.22). In terms of patterns of activity <em>P. tajacu</em>, <em>N. narica</em> and <em>Odocoileus virginianus</em> were primarily diurnal species; <em>Canis latrans</em> and <em>Leopardus pardalis</em> did not show preference for any schedule in particular, and <em>Didelphis virginiana</em> and <em>Dasypus novemcinctus</em> preferred to have nocturnal activity. This information can be of help to the creation of programs of management and conservation of mammals of medium and large in the Isthmus of Tehuantepec, Oaxaca, México.</p>


1995 ◽  
Vol 9 (4) ◽  
pp. 703-709 ◽  
Author(s):  
Gregory J. Endres ◽  
William H. Ahrens

Field experiments were conducted to evaluate postplant crop residue, green and yellow foxtail control, and wheat grain yield after fall application of trifluralin granules in undisturbed small grain stubble. Levels of postplant residue were at least 48% cover (line transect method) and 2750 kg/ha of aboveground dry matter where herbicide granules were left unincorporated or were incorporated with conservation-till methods, including an undercutter, rotary hoe, or undercutter followed by a rotary hoe. Trifluralin at 0.56 kg/ha applied as granules in mid October in untilled stubble and incorporated with conservation-till methods controlled foxtail 81 to 88%, with control appearing slightly lower when granules were not incorporated. The 81 to 88% foxtail control in conservation-till treatments was comparable to control achieved with trifluralin at 0.56 kg/ha applied in mid October on conventionally-tilled soil and incorporated by a field cultivator. Foxtail control improved somewhat as trifluralin rate was increased to 0.84 and 1.12 kg/ha in conservation-till treatments. Slight wheat stand reductions at 1.12 kg/ha of trifluralin did not appear to reduce wheat yield. Fall application of trifluralin granules in these high-residue conditions apparently minimizes herbicide losses by photodecomposition and volatility, thereby facilitating good trifluralin efficacy the following season.


Biometrics ◽  
2003 ◽  
Vol 59 (3) ◽  
pp. 512-520 ◽  
Author(s):  
Hiroshi Okamura ◽  
Toshihide Kitakado ◽  
Kazuhiko Hiramatsu ◽  
Mitsuyo Mori

2003 ◽  
Vol 59 (1) ◽  
pp. 79-87 ◽  
Author(s):  
Dolores R. Piperno ◽  
John G. Jones

AbstractA phytolith record from Monte Oscuro, a crater lake located 10 m above sea level on the Pacific coastal plain of Panama, shows that during the Late Pleistocene the lake bed was dry and savanna-like vegetation expanded at the expense of tropical deciduous forest, the modern potential vegetation. A significant reduction of precipitation below current levels was almost certainly required to effect the changes observed. Core sediment characteristics indicate that permanent inundation of the Monte Oscuro basin with water occurred at about 10,500 14C yr B.P. Pollen and phytolith records show that deciduous tropical forest expanded into the lake’s watershed during the early Holocene. Significant burning of the vegetation and increases of weedy plants at ca. 7500 to 7000 14C yr B.P. indicate disturbance, which most likely resulted from early human occupation of the seasonal tropical forest near Monte Oscuro and the development of slash-and-burn methods of cultivation.


IAWA Journal ◽  
1987 ◽  
Vol 8 (2) ◽  
pp. 143-148 ◽  
Author(s):  
Josefina Barajas-Morales

The specific gravity of 220 woody species, half of them from a tropical rainforest, half from a tropical deciduous forest was measured. The two groups were compared using a Student t-test. The results show highly significant differences in specific gravity between the species from the two areas: woods from the dry deciduous forest tend to be much heavier than those from the rainforest.


Ring ◽  
2006 ◽  
Vol 28 (2) ◽  
pp. 119-125
Author(s):  
Michał Ciach ◽  
Dominik Wikar ◽  
Małgorzata Bylicka

Density and Flock Size of the Raven (Corvus corax) In the Orawa - Nowy Targ Basin During Non-Breeding Season During the 2002/2003-2004/2005 non-breeding seasons the density of the Raven in the open habitats of the Orawa - Nowy Targ Basin was studied by line transect method. The results were analysed in four periods (autumn, early winter, winter and early spring). The median density of Ravens did not differ significantly between individual periods and was respectively: 3.5, 3.8, 4.8 and 3.8 indiv. / 10 km. Number of birds during particular controls varied from 1.0 to 24.8 indiv. / 10 km. However, while excluding flocks, the median density of single individuals and pairs of the Raven was considerably lower and in subsequent periods reached respectively: 2.2, 2.4, 2.2 and 1.7 indiv. / 10 km. Flock size did not differ significantly between individual periods. Single individuals and, less often, groups of two birds were recorded mostly. Small (3-5 indiv.) and medium (6-15 indiv.) flocks were recorded rarely and large flocks (16 indiv. and above) - only exceptionally. The high density and strong fluctuations of abundance of Ravens were determined by flocks presence, which was probably linked to irregular occurrence of food resources.


Biotropica ◽  
2008 ◽  
Vol 40 (4) ◽  
pp. 422-431 ◽  
Author(s):  
Edwin Lebrija-Trejos ◽  
Frans Bongers ◽  
Eduardo A. Pérez-García ◽  
Jorge A. Meave

Biotropica ◽  
2009 ◽  
Vol 41 (3) ◽  
pp. 347-353 ◽  
Author(s):  
Lisette Cantú-Salazar ◽  
Mircea G. Hidalgo-Mihart ◽  
Carlos A. López-González ◽  
Alberto González-Romero

Check List ◽  
2012 ◽  
Vol 8 (3) ◽  
pp. 432 ◽  
Author(s):  
Joydeb Majumder ◽  
Rahul Lodh ◽  
B. K. Agarwala

Quantification of butterfly diversity and species richness is of prime importance for evaluating the status of protected areas. Permanent line transect counts were used to record species richness and abundance of butterfly communities of different habitat types in Trishna wildlife sanctuary. A total of 1005 individuals representing 59 species in 48 genera belonging to five families were recorded in the present study. Of these, 23 species belonged to the family Nymphalidae and accounted for 38.98% of the total species and 45.20% of the total number of individuals. Mature secondary mixed moist deciduous forest showed the maximum diversity and species richness, while exotic grassland showed minimum diversity and species richness. Out of 59 species, 31 are new records for Tripura state, while 21 are unique species and nine are listed in the threatened category. This study revealed that mature secondary forests are more important for butterfly communities, while exotic grasslands have a negative impact on species composition.


Author(s):  
Yona Aksa Lewerissa

Background: Decreasing of sea cucumber resources on numbers and size of fishing capture in Negeri Porto waters influenced its community structures. Further, water environment steadiness will questionable. For this reason, study was done to analyzed community structures of sea cucumbers include of numbers species found, density, potency, species presence frequency, distribute pattern, ecology index and environment measurement. Method: Research done on February to May, 2008 at Negeri Porto used Line Transect Method. Result: showed there were eight species of sea cucumbers found (potency as much as 12.286 individuals). Bohadschia marmorata got highest in numbers species found, density, potency and species presence frequency. There were three distribute pattern of sea cucumbers found wich are uniform, random and group. Conclusion: Sea cucumbers diversity was in lower, species are closed to compatible. B. marmorata and Holothuria edulis are tends to dominate this water. Environment factors such temperature, pH, salinity, DO, turbidity, current and sediment distribute showed that Porto waters was suitable to sea cucumbers growth.


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