Human impact

Vogiatzakis, I. N., Griffiths, G. H. & Bacchetta, G. 2005: Human impacts on Quercus suber habitats in Sardinia: Past and present. Bot. Chron. 18(1): 293-300. Quercus suber L. is a species confined to the centre and western Mediterranean basin. On the island of Sardinia its distribution is limited mainly by soils. Apart from its economic significance to local communities, cork oak habitats are recognised as having both cultural and biodiversity value at a European level. Although traditionally associated with human activities these habitats are today under increasing threat. Among the problems that affect cork oak habitats on the island are soil erosion and loss of organic matter due to ploughing and seeding for pasture. Stock numbers have increased while grazing cattle have been replaced by sheep and are proven to be particularly damaging especially to cork oak regeneration. Although the species is a passive pyrophyte, frequent fires render the trees susceptible to fungal and defoli...

The relationship between species and functional diversity remains poorly understood for nearly all ecosystem types, yet determining this relationship is critically important for developing both a mechanistic understanding of community assembly and appropriate expectations and approaches to protecting and restoring biological communities. Here we use two distinct data sets, one from kelp forests in the Channel Islands, California, and one from a global synthesis of marine reserves, to directly test how ...

The transformation of the Earth’s land surface by mineral extraction and construction is on a scale greater than natural erosive terrestrial geological processes. Mineral extraction statistics can be used as a proxy to measure the size of the total anthropogenic global sediment flux related to mineral extraction and construction. It is demonstrated that the annual direct anthropogenic contribution to the global production of sediment in 2015 was conservatively some 316 Gt (150 km3), a figure more than 24 times greater than the sediment supplied annually by the world’s major rivers to the oceans. The major long-term acceleration in anthropogenic sediment flux started just after the Second World War and anthropogenic sediment flux overtook natural fluvial sediment flux in the mid-1950s. Humans are now the major global geomorphological driving force and an important component of Earth System processes in landscape evolution. The changing magnitude of anthropogenic sediments and landfor...

Human intervention in the hydrologic basin of the Colorado River has eliminated water discharge and sediment supply to the river's mouth and its delta. After ∼95 years of applying strong flow control policies, the previous sedimentary budget in the delta has changed, the delta now being entirely exposed to the hydrodynamic forces in its basin. In order to assess the anthropogenic impact of water diversion on deltaic sedimentary processes and short-term delta geomorphic evolution, textural and mineralogical analyses were performed on 68 sediment samples collected from the river, estuary, beach, continental shelf, delta plain and desert. The results show a consistent NE to SW textural gradient on the shallow-marine platform adjacent to the Colorado River delta (an area known as the Upper Gulf of California), and a net cross-basinal sediment transport occurring in the same direction. Two opposing littoral transport components exist along the Sonoran and Baja Californian coasts: (1) net sediment transport from SE to NW along the Sonoran coast delivers sediments from the ocean into the estuarine basin through the Sonora channel of the deltaic system of the Colorado River; and (2) sediment transport from N to S along the Baja Californian coast removes sediments from the estuarine basin of the Colorado River into the Northern Gulf of California (NGC). The residual sediment transport pattern observed suggests a counterclockwise path of exchange of materials between the estuarine basin of the Colorado River and the NGC. Multivariate cluster and factor analyses of the heavy-mineral data reveal the existence of a sedimentary system dominated by two end-members, representing two heavy-mineral sedimentary provinces: (1) the Sonora province is characterized by a heavy-mineral suite of garnet and zircon (G–Z), whose sediment supply originates from the sandy sediments of the Sonora Mesa deposits and Sonora's Gran Desierto; and (2) the Baja California province is characterized by a hornblende–epidote–pyroxene (H–E–P) suite, whose sediments originate from the earlier supply of the Colorado River. Since the Colorado River is no longer supplying sediments from its drainage basin, the H–E–P-rich sediments now actively dispersed in the system have mainly originated through intense reworking of the delta. Moreover, G–Z-rich sediments are starting to invade areas previously dominated by H–E–P sediments. On the basis of the prevailing hydraulic regime, textural and mineralogical characteristics of the sediments, and hydrographic and bathymetric information from the region, a hypothetical sediment dynamics model for the delta region is proposed, in which the tidally influenced, wave-dominated, sediment-reworked, slightly eroding Sonoran coast changes into a tide-dominated, depositional, very slowly prograding Baja Californian coast. This study shows that human intervention of the hydrologic basin of the Colorado River is not only responsible for inducing drastic hydrologic changes in its estuary (i.e., from brackish to hypersaline), but also for inducing drastic changes in the hydrographic circulation of the receiving basin (i.e., from long-basinal to cross-basinal). These changes are ultimately responsible for the relocation of massive volumes of the delta's sediment inventory, and for the serious ecological impact of habitat loss of indigenous species, such as the now endangered Totoaba (Totoaba macdonaldi) and Vaquita (Phocoena sinus).

This report summarises the status of coral reefs in the ROPME Sea Area which includes Bahrain, Iran, Kuwait, Oman, Qatar, Saudi Arabia and United Arab Emirates (UAE); there are no coral reefs in Iraq. The region can be split into three parts according to the local marine climate, which strongly influences the nature of the coral communities: the Persian/Arabian Gulf

Riparian vegetation and management of surface water, the case of the Inaouène-Wadi watershed (NW Morocco). Integrated management of water resources interfere, directly or indirectly, with the biodiversity conservation. In Morocco, most studies on plant diversity of wetland interested especially ecological and functioning aspects. In this work, we tried to establish a relationship between human activities (planning, pollution …) and wetland flora and its conservation status. The specific plant diversity (Spermatophyta and Pteridophyta) of the Inaouène River was estimated based on the riparian flora exploration of 21 stations. The main ecological and anthropogenic factors (sampling, planning …) affecting plant groups were discussed as elements interfering with the rivers management. The study highlights the dependence of the population vis-à-vis plant resources, which may have a negative impact on surface water, and more rational measures should be taken, namely the plantation of the ...

This report summarises the status of coral reefs in the ROPME Sea Area which includes Bahrain, Iran, Kuwait, Oman, Qatar, Saudi Arabia and United Arab Emirates (UAE); there are no coral reefs in Iraq. The region can be split into three parts according to the local marine climate, which strongly influences the nature of the coral communities: the Persian/Arabian Gulf

Although the phytoplankton and protozoan assemblages of Lake Winnipeg are quite variable both, spatial and temporally, knowledge of their current distribution and ecology enables them to be used as indicators providing unique information concerning past and recent ecosystem conditions. Many of the main taxa have been similar throughout history although there have been dramatic changes in their abundance. Lake Winnipeg

Detailed palynological studies in two adjoining French Pyrenean valleys, complemented by the study of archives, demonstrate that under similar climatic conditions, the forest history of each valley from the Bronze Age to present time was essentially determined by socio-economical constraints, possibly modified by natural characteristics such as topography. The studies show why the expansion of Fagus (beech) at c. 4000 B.P. was asynchronous on the northern slope of the Pyrenees and emphasize the effects of the human impact on the recent lowering of the tree-line.

The aim of this study is to elaborate a synthetic document for the assessment of groundwater vulnerability to pollution in the Hajeb-Jelma aquifer. The specific object is to incorporate the Geographical Information System (GIS) to generate groundwater vulnerability and risk maps with DRASTIC model. Indeed, GIS could help to make the results of a complicated model more clear through visual representation, providing an applicable tool for decision makers. The vulnerability map of Hajeb-Jelma watershed shows three classes: moderate, high and very high depending on the intrinsic properties. The risk map shows a very high risk dependant on hydrogeological characteristics, land use and human impacts in major part of the Hajeb-Jelma region. These maps could serve as a scientific basis for sustainable land use planning and groundwater management in the Hajeb-Jelma region.

A multi-proxy approach study (cladocerans, diatoms, geochemistry, plant macrofossils, pollen), was performed on a sediment core from Lake Vrana (Vransko Jezero), a large and deep karstic lake on the northern Adriatic island of Cres, Croatia. Considerable lake-level changes occurred during the last approx. 16,000 years. The stratigraphic evidence suggests that periods of enhanced pre- cipitation and the post-LGM rise in