scholarly journals Assessing the Structure and Drivers of Biological Sounds Along a Disturbance Gradient

2021 ◽  
pp. e01819
Author(s):  
Johan Diepstraten ◽  
Jacob Willie
Keyword(s):  
Disturbance Gradient

Richness, Community Structure, and Diurnal Activity of Species of Ants along a Disturbance Gradient at El Cielo Biosphere Reserve, Tamaulipas, Mexico

2018 ◽  
Vol 43 (4) ◽  
pp. 919-938 ◽  
Author(s):  
Itzel Rubí Rodríguez-de León ◽  
Crystian Sadiel Venegas-Barrera ◽  
Miguel Vásquez-Bolaños ◽  
Alfonso Correa-Sandoval ◽  
Jorge Víctor Horta-Vega
Keyword(s):  
Community Structure ◽  
Biosphere Reserve ◽  
Diurnal Activity ◽  
Disturbance Gradient ◽  
El Cielo Biosphere Reserve

scholarly journals Macroinvertebrate community responses to a dewatering disturbance gradient in a restored stream

2011 ◽  
Vol 15 (6) ◽  
pp. 1771-1783 ◽  
Author(s):  
J. D. Muehlbauer ◽  
M. W. Doyle ◽  
E. S. Bernhardt
Keyword(s):  
Species Abundance ◽  
Recovery Process ◽  
Macroinvertebrate Community ◽  
Summer Drought ◽  
Community Responses ◽  
Disturbance Gradient ◽  
Habitat Refugia ◽  
Species Groups ◽  
Community Variability ◽  
Strong Control

Abstract. Dewatering disturbances are common in aquatic systems and represent a relatively untapped field of disturbance ecology, yet studying dewatering events along gradients in non-dichotomous (i.e. wet/dry) terms is often difficult. Because many stream restorations can essentially be perceived as planned hydrologic manipulations, such systems can make ideal test-cases for understanding processes of hydrological disturbance. In this study we used an experimental drawdown in a 440 ha stream/wetland restoration site to assess aquatic macroinvertebrate community responses to dewatering and subsequent rewetting. The geomorphic nature of the site and the design of the restoration allowed dewatering to occur predictably along a gradient and decoupled the hydrologic response from any geomorphic (i.e. habitat heterogeneity) effects. In the absence of such heterogeneous habitat refugia, reach-scale wetted perimeter and depth conditions exerted a strong control on community structure. The community exhibited an incremental response to dewatering severity over the course of this disturbance, which was made manifest not as a change in community means but as an increase in community variability, or dispersion, at each site. The dewatering also affected inter-species abundance and distributional patterns, as dewatering and rewetting promoted alternate species groups with divergent habitat tolerances. Finally, our results indicate that rapid rewetting – analogous to a hurricane breaking a summer drought – may represent a recovery process rather than an additional disturbance and that such processes, even in newly restored systems, may be rapid.

Changes in escape behaviour of black iguanas (Ctenosaura similis) over an anthropogenic disturbance gradient

Behaviour ◽  
2021 ◽  
pp. 1-21
Author(s):  
Pooja Panwar ◽  
Pilar Angélica Gómez-Ruiz ◽  
Matthew N. Zipple ◽  
Luis Sandoval
Keyword(s):  
Human Disturbance ◽  
Protected Area ◽  
Anthropogenic Disturbance ◽  
Escape Behaviour ◽  
Human Presence ◽  
Disturbed Areas ◽  
Disturbance Gradient ◽  
The Impact ◽  
Ctenosaura Similis ◽  
Flight Initiation

Abstract Studies on the impact of human activity on animal behaviour are critical for understanding the extent to which humans affect ecological dynamics. Previous studies have found that human presence alters antipredator behaviours, which can be measured by flight initiation distance (FID). We investigated escape behaviour of 96 black iguanas (Ctenosaura similis) across a gradient of human disturbance in six sites inside a protected area in Costa Rica. We used a field experiment to test for effect of human disturbance on FID. We found that individuals from higher disturbance sites had shorter FIDs, meaning that black iguanas from disturbed areas allow closer approaches. This finding is consistent with the prediction that some animals become more habituated to human presence as the degree of human disturbance increases. We propose that black iguanas’ ability to alter their behaviour in response to humans’ presence could make them especially adept at invading new environments.

scholarly journals Spatial and temporal variation of CO<sub>2</sub> efflux along a disturbance gradient in a <i>miombo</i> woodland in Western Zambia

2011 ◽  
Vol 8 (1) ◽  
pp. 147-164 ◽  
Author(s):  
L. Merbold ◽  
W. Ziegler ◽  
M. M. Mukelabai ◽  
W. L. Kutsch
Keyword(s):  
Soil Respiration ◽  
Soil Temperature ◽  
Temporal Variation ◽  
Carbon Content ◽  
Ecosystem Respiration ◽  
Spatial And Temporal Variation ◽  
Co2 Efflux ◽  
Forest Reserve ◽  
Disturbance Gradient ◽  
Total Ecosystem Respiration

Abstract. Carbon dioxide efflux from the soil surface was measured over a period of several weeks within a heterogeneous Brachystegia spp. dominated miombo woodland in Western Zambia. The objectives were to examine spatial and temporal variation of soil respiration along a disturbance gradient from a protected forest reserve to a cut, burned, and grazed area outside, and to relate the flux to various abiotic and biotic drivers. The highest daily mean fluxes (around 12 μmol CO2 m−2 s−1) were measured in the protected forest in the wet season and lowest daily mean fluxes (around 1 μmol CO2 m−2 s−1) in the most disturbed area during the dry season. Diurnal variation of soil respiration was closely correlated with soil temperature. The combination of soil water content and soil temperature was found to be the main driving factor at seasonal time scale. There was a 75% decrease in soil CO2 efflux during the dry season and a 20% difference in peak soil respiratory flux measured in 2008 and 2009. Spatial variation of CO2 efflux was positively related to total soil carbon content in the undisturbed area but not at the disturbed site. Coefficients of variation of efflux rates between plots decreased towards the core zone of the protected forest reserve. Normalized soil respiration values did not vary significantly along the disturbance gradient. Spatial variation of respiration did not show a clear distinction between the disturbed and undisturbed sites and could not be explained by variables such as leaf area index. In contrast, within plot variability of soil respiration was explained by soil organic carbon content. Three different approaches to calculate total ecosystem respiration (Reco) from eddy covariance measurements were compared to two bottom-up estimates of Reco obtained from chambers measurements of soil- and leaf respiration which differed in the consideration of spatial heterogeneity. The consideration of spatial variability resulted only in small changes of Reco when compared to simple averaging. Total ecosystem respiration at the plot scale, obtained by eddy covariance differed by up to 25% in relation to values calculated from the soil- and leaf chamber efflux measurements but without showing a clear trend.

scholarly journals Impacts of Skidding Traffic Intensity on Soil Disturbance, Soil Recovery, and Aspen Regeneration in North Central Minnesota

2007 ◽  
Vol 24 (3) ◽  
pp. 177-183 ◽  
Author(s):  
Eric K. Zenner ◽  
Jeremiah T. Fauskee ◽  
Alaina L. Berger ◽  
Klaus J. Puettmann
Keyword(s):  
Populus Tremuloides ◽  
Soil Surface ◽  
Soil Disturbance ◽  
Quaking Aspen ◽  
Partial Recovery ◽  
Traffic Intensity ◽  
Basal Diameter ◽  
Disturbance Gradient ◽  
Soil Recovery ◽  
Number Of Passes

Abstract We investigated the effects of different levels of ground-based skidding traffic intensity on soil disturbance, characterized by resistance to penetration (RP) within the top 15 cm of soil, as well as soil recovery, regeneration, and early growth of quaking aspen (Populus tremuloides Michx.) suckers 3 years after a clearcut with reserves summer harvest. Equipment traffic was confined to a network of skid trails, and a GPS was used to determine the number of skidder passes at each of 30 sampling points that were preestablished along an anticipated disturbance gradient ranging from landings to skid trails to areas off skid trails. Thirty-one percent of the harvest area was affected by skid traffic, and up to 603 passes were recorded for a plot. RP increased nonlinearly with the number of passes and reached highest levels at the soil surface. Three years after harvest, soils showed partial recovery in the upper 10-cm layer, with full recovery of the surface layer (0–5 cm depth) when affected by 4 or fewer passes. The deepest layer (10–15 cm), however, showed little recovery since harvest. Sucker density, height, and basal diameter of all suckers and height, basal diameter, and dbh of the tallest suckers were significantly reduced with increasing traffic intensity but were not related to increases in RP. Predicted reduction of sucker density was approximately one-third after 10 passes; reductions of height, basal diameter, and dbh were between 1.5 and 2.5% at 10 passes and 3.5 and 6.5% at 25 passes. Because skidding traffic affected only a limited portion of the stand, the productivity of the future aspen stand was not severely impaired, at least in the very short term.

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