scholarly journals Edge effect on the population structure and the reproductive success of two Bursera species

2017 ◽  
Vol 95 (1) ◽  
pp. 9 ◽  
Author(s):  
Humberto Suzán-Azpiri ◽  
Oscar O Ponce-González ◽  
Guadalupe X. Malda-Barrera ◽  
Victor H. Cambrón-Sandoval ◽  
Israel G. Carrillo-Angeles

<p><strong>Background</strong>: Environmental conditions in edges of vegetation fragments affect life cycle characteristics of the native biota (edge effect). We evaluated the edge effect on two <em>Bursera</em> species, which are representative of the mature community of the tropical deciduous forest (TDF) in Mexico.</p><p><strong>Hypothesis</strong>. We expected a population structure reflecting the affectation to reproduction, survival and growth in the edges of TDF fragments.</p><p><strong>Studied species:</strong><em> Bursera fagaroides</em>, <em>B. Palmeri.</em></p><p><strong>Study site and years of study:</strong> Querétaro (Qro.), Apaseo el Grande (Gto.), México. Field survey: May-September 2012.</p><p><strong>Methods:</strong> Within each of nine TDF fragments, we drew plots in two environmental contrasting conditions (edge and interior), between which we compared the density, population structure and reproductive success of the two <em>Bursera</em> species, as well as estimators of the solar radiation and soil compaction.</p><p><strong>Results:</strong> Solar radiation and soil compaction were not different between environmental conditions. In both species density of individuals was larger in the edge, where individuals with middle and large sizes were predominant. Reproductive potential of individuals, and the viability and germination of their seeds were similar between edge and core environments.</p><p><strong>Conclusions:</strong> Density and population structure showed a congruent variation with higher rates of recruitment, growth and survival in the edge environment, which could have been present under initial conditions of greater incidence of radiation in the edges. The similarity currently observed in the solar radiation between edge and core areas of fragments, could be a result of the fast recovery of the canopy under conditions of higher light incidence in edges.</p>

2004 ◽  
Vol 26 (1) ◽  
pp. 45 ◽  
Author(s):  
AD Bilton ◽  
DB Croft

Female reproductive success and the recruitment of offspring to the next generation are key components of animal population dynamics. With an annual commercial harvest of between 13 and 22% of the red kangaroo (Macropus rufus) population, it is increasingly important that these processes are understood. We used data on the reproductive success of 33 free-ranging female M. rufus on Fowlers Gap station in far western New South Wales to determine the expected lifetime reproductive success (LRS) of females within an unharvested population. We also designed a model to generate predictions about female LRS incorporating empirical relationships between a mother?s reproductive success and maternal age, environmental conditions and the sex and survivorship of a previous reproductive attempt. Results from observations on female LRS (calculated from annual weaning rates) and those generated by the model predict that female M. rufus on ?Fowlers Gap? wean, on average, 3.7 young in a lifetime (ranges 0 - 11 and 0 - 20, respectively); representing only 41% of their maximum reproductive potential. Manipulation of initial starting conditions allowed the effect of varying environmental conditions on female LRS to be explored. The condition of the environment when females commence breeding does not appear to significantly affect their overall lifetime reproductive output. However, the occurrence of drought does. Females experiencing two droughts in a lifetime did not live as long and weaned fewer offspring and grandoffspring (from their daughters) than those females experiencing only one drought in a lifetime. In addition to the adverse effect of drought on the reproductive success of female M. rufus in this study, we suggest that, given the relatively high and stable population densities of M. rufus on ?Fowlers Gap?, other mechanisms (acting primarily on juvenile survival) must exist which limit population growth.


CATENA ◽  
1999 ◽  
Vol 36 (1-2) ◽  
pp. 153-164 ◽  
Author(s):  
L Galicia ◽  
J López-Blanco ◽  
A.E Zarco-Arista ◽  
V Filips ◽  
F Garcı́a-Oliva

2021 ◽  
Vol 11 (7) ◽  
pp. 3084-3092
Author(s):  
Pablo Capilla‐Lasheras ◽  
Blanca Bondía ◽  
José I. Aguirre

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.


2017 ◽  
Vol 17 (3) ◽  
pp. 39-56 ◽  
Author(s):  
Sérgio Roberto Andrade Dantas ◽  
Fulvio Vittorino ◽  
Kai Loh

Abstract Contact of facades with degradation agents and direct incidence of ultraviolet radiation on external coatings make them more opaque over time, affecting their colour and reflectance characteristics. This study evaluated the effect of adding different TiO2 contents to mortars applied in concrete substrates in order to verify the reflectance maintenance on surfaces after exposure over time. Mortar with different concentrations of TiO2 (1%, 5%, 10%) were produced in relation to the total dry premix, added as a powder and compared to unpainted mortar without TiO2 (type "A") and painted mortar without TiO2 (type "B"), both used as a reference for colour and reflectance. Exposed over 16 months to climate conditions in São Paulo, regarding the maintenance of reflectance and solar radiation, the results showed that type "B" (0%TiO2) painted mortar presented the best performance. Type "C" (1%TiO2) and type "D" (5%TiO2) unpainted mortar remained more stable. Type "A" (0%TiO2) and type "E" (10%TiO2) unpainted mortar showed greater differences according to the Just Noticeable Difference (JND) range caused by dirt pick up.


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

2018 ◽  
Vol 240 ◽  
pp. 04004 ◽  
Author(s):  
Marek Jaszczur ◽  
Qusay Hassan ◽  
Janusz Teneta ◽  
Ewelina Majewska ◽  
Marcin Zych

The operating temperature of the photovoltaic module is an important issue because it is directly linked with system efficiency. The objective of this work is to evaluate temperature distribution in the photovoltaic module under different environmental conditions. The results shown that photovoltaic module operating temperature depends not only on the ambient temperature or solar radiation dependent but also depends on wind speed and wind direction. It is presented that the mounting conditions which are not taken into consideration by most of the literature models also play a significant role in heat transfer. Depends on mounting type an increase in module operating temperature in the range 10-15oC was observed which cause further PV system efficiency decrease of about 3.8-6.5 %.


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