scholarly journals Acacia invasion is facilitated by landscape permeability: The role of habitat degradation and road networks

2020 ◽  
Vol 23 (4) ◽  
pp. 598-609
Author(s):  
Gustavo Heringer ◽  
Jan Thiele ◽  
Cibele Hummel Amaral ◽  
João Augusto Alves Meira‐Neto ◽  
Fabio Antonio Ribeiro Matos ◽  
...  
Keyword(s):  
Habitat Degradation ◽  
Road Networks ◽  
Landscape Permeability

scholarly journals Defining the niche for niche construction: evolutionary and ecological niches

2021 ◽  
Vol 36 (3) ◽  
Author(s):  
Rose Trappes
Keyword(s):  
Evolutionary Biology ◽  
Ecological Niche ◽  
Niche Construction ◽  
Habitat Degradation ◽  
Ecological Niches ◽  
Niche Concept ◽  
Definition Of ◽  
Compare And Contrast ◽  
Extreme Habitat

AbstractNiche construction theory (NCT) aims to transform and unite evolutionary biology and ecology. Much of the debate about NCT has focused on construction. Less attention has been accorded to the niche: what is it, exactly, that organisms are constructing? In this paper I compare and contrast the definition of the niche used in NCT with ecological niche definitions. NCT’s concept of the evolutionary niche is defined as the sum of selection pressures affecting a population. So defined, the evolutionary niche is narrower than the ecological niche. Moreover, when contrasted with a more restricted ecological niche concept, it has a slightly different extension. I point out three kinds of cases in which the evolutionary niche does not coincide with realized ecological niches: extreme habitat degradation, commensalism, and non-limiting or super-abundant resources. These conceptual differences affect the role of NCT in unifying ecology and evolutionary biology.

The role of connectivity in Australian conservation

2004 ◽  
Vol 10 (4) ◽  
pp. 266 ◽  
Author(s):  
M. E. Soulé ◽  
B. G. Mackey ◽  
H. F. Recher ◽  
J. E. Williams ◽  
J. C. Z. Woinarski ◽  
...  
Keyword(s):  
Large Scale ◽  
Biological Diversity ◽  
Ecological Resilience ◽  
Landscape Permeability ◽  
Conservation Assessment ◽  
Ecological Processes ◽  
Trophic Relations ◽  
Scientific Framework

The existing system of nature reserves in Australia is inadequate for the long-term conservation and restoration of native biological diversity because it fails to accommodate, among other elements, large scale and long-term ecological processes and change, including physical and biotic transport in the landscape. This paper is an overview of the connectivity elements that inform a scientific framework for significantly improving the prospects for the long-term conservation of Australia's biodiversity. The framework forms the basis for the WildCountry programme. This programme has identified connectivity at landscape, regional and continental scales as a critical component of an effective conservation system. Seven categories of ecological phenomena are reviewed that require landscape permeability and that must be considered when planning for the maintenance of biological diversity and ecological resilience in Australia: (1) trophic relations at regional scales; (2) animal migration, dispersal, and other large scale movements of individuals and propagules; (3) fire and other forms of disturbance at regional scales; (4) climate variability in space and time and human forced rapid climate change; (5) hydroecological relations and flows at all scales; (6) coastal zone fluxes of organisms, matter, and energy; and, (7) spatially-dependent evolutionary processes at all scales. Finally, we mention eight cross-cutting themes that further illuminate the interactions and implications of the seven connectivity-related phenomena for conservation assessment, planning, research, and management, and we suggest how the results might be applied by analysts, planners, scientists, and community conservationists.

Effects of riparian woody vegetation on EPT functional connectivity in Western Germany

2021 ◽  
Author(s):  
Andrés Peredo Arce ◽  
Martin Palt ◽  
Martin Schletterer ◽  
Jochem Kail
Keyword(s):  
Water Pollution ◽  
Functional Connectivity ◽  
Riparian Vegetation ◽  
Habitat Degradation ◽  
Riparian Forest ◽  
Landscape Connectivity ◽  
Riparian Forests ◽  
Coniferous Forests ◽  
Western Germany

<p>In the degraded European landscapes riparian corridors had have become key features to maintain connectivity between habitat patches for multitude of organisms. This role of riparian forests has been assessed from the purely structural point of view, to complex models specific for particular species or groups of species, from mammals to plants, from endangered to invasive species.</p><p>Dispersion is a key part of the lifecycle of EPTs (Ephemeroptera, Plecoptera and Trichoptera) as they live most of their lives as aquatic juveniles, being drifted downstream, and disperse back upstream when they become short-lived winged adults. These three families of aquatic macroinvertebrates are widely used as bioindicators because of their sensitivity to water pollution and habitat degradation, but little is known about how the riparian vegetation impacts their ability to disperse and recolonize. For example, riparian vegetation could help EPTs dispersion by protecting them from harsh weather conditions, or by helping them to orientate themselves by changing how the reflexion of the light on the water polarises.</p><p>Nevertheless, connectivity is not the only driver of the EPT community as other parameters can have a direct effect on the community composition. For example, water pollution is an important driver of the freshwater macroinvertebrate community and in locations where pollution is high is not expected to find almost any EPTs individual regardless of the landscape connectivity. Furthermore, other landscape features can hinder the role of riparian forests as corridors for being a barrier to EPT dispersion, like dams or coniferous forests.</p><p>In this study we compare the EPT communities on 120 pairs of sites, each pair located in the same river at 1 to 5 km distance, with different riparian vegetation conditions in Western Germany. The communities are characterised by their overall dispersion capacity using the Species Flying Propensity index (Sarremejane et al. 2017). The riparian vegetation is identified using areal images in the 10 meters and 30 meters buffer from the river.</p><p>We expect that riparian forest fragmentation will directly impact functional connectivity, and therefore, in locations with less fragmented riparian forests the EPT community will be mainly composed by weak dispersers (and <em>vice versa</em>). Nevertheless, covariates that can impact or mask this effect were taken into account: catchment land use, saprobic pollution, naturalness, hidromorphological hydromorphological degradation and also other features as coniferous forests or dams.</p>

ON THE ROLE OF ROAD NETWORKS IN REDUCING HUMAN LOSSES AFTER EARTHQUAKES

2006 ◽  
Vol 10 (2) ◽  
pp. 195-206 ◽  
Author(s):  
PAOLO FRANCHIN ◽  
ALESSIO LUPOI ◽  
PAOLO E. PINTO
Keyword(s):  
Road Networks ◽  
Human Losses

Evaluating the role of invasive aquatic species as drivers of fine sediment-related river management problems: The case of the signal crayfish (Pacifastacus leniusculus)

2011 ◽  
Vol 35 (4) ◽  
pp. 517-533 ◽  
Author(s):  
Gemma L. Harvey ◽  
Tom P. Moorhouse ◽  
Nicholas J. Clifford ◽  
Alexander J. Henshaw ◽  
Matthew F. Johnson ◽  
...  
Keyword(s):  
Invasive Species ◽  
Habitat Degradation ◽  
River Sediments ◽  
Large Body ◽  
Aquatic Organisms ◽  
Mitigation Strategies ◽  
Catchment Scale ◽  
Signal Crayfish ◽  
River Bed

Sediment quantity and quality are key considerations in the sustainable management of fluvial systems. Increasing attention is being paid to the role of aquatic biota as geomorphic agents, capable of altering the composition, mobilization and transport of fluvial sediments at various spatiotemporal scales. In this paper invasive species are presented as a special case since: (1) populations may not be constrained by factors characteristic of their native habitats; and (2) they represent a disturbance to which the system may not be resilient. Discussion is centred on the signal crayfish which has rapidly colonized catchments in Europe and Japan, but the hypotheses and models presented provide a framework applicable to other invasive species. This paper explores the mechanisms by which signal crayfish may influence sediment dynamics from the patch scale to the catchment scale. There is potential for signal crayfish to impact significantly on river sediments and morphology as a function of their interactions with river bed and bank material, and with other aquatic organisms, combined with their large body size and aggressive nature, their presence in very high densities, and the lack of effective mitigation strategies. Potential catchment-scale management issues arising from these factors include habitat degradation, mobilization of sediment-associated nutrients and contaminants, and sediment-related flood risks. Further interdisciplinary research is required at the interface between freshwater ecology, fluvial geomorphology and hydraulics, in order to quantify the significance and extent of these impacts. The paper points to the key research agendas that may now emerge.

scholarly journals Biodiversity Patterns of Macroinvertebrate Assemblages in Natural and Artificial Lentic Waters on an Oceanic Island

2021 ◽  
Vol 8 ◽  
Author(s):  
Lucas Lamelas-López ◽  
Paulo A. V. Borges ◽  
Laura Serrano ◽  
Vitor Gonçalves ◽  
Margarita Florencio
Keyword(s):  
Habitat Degradation ◽  
Temporary Ponds ◽  
Macroinvertebrate Assemblages ◽  
Β Diversity ◽  
Spatial Influence ◽  
Physico Chemical ◽  
Monthly Pattern ◽  
High Concentrations ◽  
Lentic Waters

The Azorean islands have been historically affected by human activities, mainly due to the combined effects of habitat degradation and fragmentation, and the introduction of exotic species. We here aim to analyze the role of environmental characteristics and spatial descriptors in supporting regional biodiversity of macroinvertebrates by considering natural ponds and artificial tanks. After the monthly variation of macroinvertebrate assemblages was assessed in three temporary and two permanent ponds in the Azorean island of Terceira during a complete inundation-desiccation annual cycle, the assemblage differences of 12 ponds (three temporary and nine permanent ponds) and 8 closely-located artificial tanks were analyzed across a range of landscape disturbances. Macroinvertebrate assemblages were found to differ according to hydroperiod and sampled months. Although the former explained the highest variance, macroinvertebrate differentiation by hydroperiod was also dependent on the study month. Our results also revealed a consistent monthly pattern of species replacement. However, the contribution of nestedness to the macroinvertebrate β-diversity was notable when temporary ponds were close to desiccation, probably indicating a deterministic loss of species due to the impoverished water conditions of the ponds facing desiccation. When the macroinvertebrate assemblages were analyzed in relation to physico-chemical variations and spatial descriptors, the artificial tanks were not clearly segregated from the natural ponds, and only differentiated by pH differences. In contrast, those natural ponds exhibiting high concentrations of total phosphorous (likely signs of anthropization) also discriminated the ordination of ponds in a distance-based redundancy analysis, and showed impoverished assemblages in comparison with well-preserved ponds. The macroinvertebrate assemblages of the natural ponds showed a significant spatial pattern, but this spatial influence was not significant when tanks and ponds were considered together. Our results suggest that tanks may act as possible reservoirs of biodiversity during the desiccation period of temporary ponds, but are unable to establish successful populations. These fishless permanent tanks can complement the conservation of a biodiversity that is largely maintained by the pristine high-altitude natural ponds. The establishment of a guideline for conservation management that also considers the artificial tanks is necessary to benefit the local and regional Azorean macroinvertebrate diversity.

scholarly journals Study of the curative role of “Draas” in evacuating dunes threatening roads in the Lower Algerian Sahara: physical model on a smaller scale

2018 ◽  
Vol 64 (4) ◽  
pp. 15-35
Author(s):  
A. K. Sebaa ◽  
M. Belhamra
Keyword(s):  
Physical Model ◽  
Road Networks ◽  
Model Tests ◽  
Flow Channel ◽  
Reduced Model ◽  
Liquid Stream ◽  
Algerian Sahara ◽  
Protective Structures

AbstractSand drifting on road networks in the region of the Lower Algerian Sahara is one of the main problems for the sector. Machines are repeatedly deployed to overcome this phenomenon. The long experience acquired while dealing with the removal of sand from roads pushed us to focus on obstacles called “Draas”. The purpose of this study is to perform an optimization of these special protective structures called “Draas”, using a reduced physical model. Model tests were performed in flow channel. The principle of modeling the wind transport using a reduced model is to simulate the wind using a liquid stream while respecting the laws of hydraulic and sedimentological similarity. The results obtained are extrapolated to make a normal size prototype.

Competitive reversals inside ecological reserves: the role of external habitat degradation

1998 ◽  
Vol 37 (6) ◽  
pp. 491-533 ◽  
Author(s):  
Robert Stephen Cantrell ◽  
Chris Cosner ◽  
William F. Fagan
Keyword(s):  
Habitat Degradation
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