Multiple Human Pressures Research Articles

Human pressures and ecological status of European rivers

Humans have increased the discharge of pollution, altered water flow regime and modified the morphology of rivers. All these actions have resulted in multiple pressures on freshwater ecosystems, undermining their biodiversity and ecological functioning. The European Union has adopted an ambitious water policy to reduce pressures and achieve a good ecological status for all water bodies. However, assessing multiple pressures on aquatic ecosystems and understanding their combined impact on the ecological status is challenging, especially at the large scale, though crucial to the planning of effective policies. Here, for the first time, we quantify multiple human pressures and their relationship with the ecological status for all European rivers. We considered ecological data collected across Europe and pressures assessed by pan-European models, including pollution, hydrological and hydromorphological alterations. We estimated that in one third of EU’s territory rivers are in good ecological status. We found that better ecological status is associated with the presence of natural areas in floodplains, while urbanisation and nutrient pollution are important predictors of ecological degradation. We explored scenarios of improvement of rivers ecological status for Europe. Our results strengthen the need to halt urban land take, curb nitrogen pollution and maintain and restore nature along rivers.

Murciélagos (Chiroptera) del departamento del Chocó, occidente colombiano

Due to its location on the northwestern corner of the subcontinent, considered epicenter of the great inter- change of biota between North and South America, the department of Choco represents one of the most important terrestrial and aquatic environments in terms of biodiversity in the American tropics. In addition, the entire area of the department is part of in the Biogeographic Choco, which corresponds to a large proportion of conservation corridor Choco-Manabi, hotspot of biodiversity, as well as the Terrestrial Ecore- gion Priority (ETP) Tumbes-Choco-Magdalena. It has been documented, that chiropterans constitute one of the most important components of such diversity. Although there are many e orts that compile the chiropterological information of the department, important advances on the documentation of this group of mammals for the region make urgent a constant evaluation of the bat diversity for the department. On this line of ideas, we present an updated list of bats for the department of Choco, which include species that have been reported in national lists and are represented in scienti c collections of national and international institutions. We report a total of 132 Chocoan bat species, corresponding to 64,4% of the chiropteranfau-na of Colombia. Among this diversity there are six species considered at risk threat (IUCN). This diversity is grouped into 59 genera, seven families and 12 subfamilies. This study increases the Chocoan richness of bats in 49%, going from 83 to 132 species. This results position the Choco as the department with the highest number of species of bats in the country, and one of the areas with the greatest bat diversity in the hemisphere. The subregion with the highest species richness in the department was Atrato with 82 species and the municipality with the highest number recorded species was Quibdo with 72 species. However, our analyses suggest a high biotic potential for the region, and at the same time, point out on the scarcity of studies and knowledge and the poor geographic coverage of diversity inventories; a serious situation if we consider the multiple and constant human pressures on nature in this portion of the country. Habitat fragmentation caused by di erent human activities (agriculture, cattle, and mining) as well as hunting are some of the most relevant anthropogenic pressures. In this scenario, it is evident the need for further research in the department, involving taxonomic and eco- logical aspects, which contribute to a better understanding of this group and provide useful tools for the conservation of bats in northwestern Colombia.

Increased anthropogenic pressure decreases species richness in tropical intertidal reefs

Multiple human stressors affect tropical intertidal sandstone reefs, but little is known about their biodiversity and the environmental impacts of these stressors. In the present study, multiple anthropogenic pressures were integrated using the relative environmental pressure index (REPI) and related to benthic community structure across an intertidal gradient in five sandstone reefs in the tropical South Atlantic coast. Greater species richness and diversity were noted in the low intertidal zones. There was a negative relationship between REPI and species richness, suggesting that increasing anthropogenic pressure has decreased benthic richness. The factors associated with the loss of richness were jetties built to control erosion, urban areas, beachfront kiosks and restaurants, fish markets, and storm sewers with illegal sewage connections. Our results highlight the need for better infrastructure planning and rigorous monitoring of coastal urban areas, since the large influence of multiple human pressures in these reefs leads to biodiversity losses.

HOW MANY HIPPOS (HOMHIP): ALGORITHM FOR AUTOMATIC COUNTS OF ANIMALS WITH INFRA-RED THERMAL IMAGERY FROM UAV

Abstract. The common hippopotamus (Hippopotamus amphibius L.) is part of the animal species endangered because of multiple human pressures. Monitoring of species for conservation is then essential, and the development of census protocols has to be chased. UAV technology is considering as one of the new perspectives for wildlife survey. Indeed, this technique has many advantages but its main drawback is the generation of a huge amount of data to handle. This study aims at developing an algorithm for automatic count of hippos, by exploiting thermal infrared aerial images acquired from UAV. This attempt is the first known for automatic detection of this species. Images taken at several flight heights can be used as inputs of the algorithm, ranging from 38 to 155 meters above ground level. A Graphical User Interface has been created in order to facilitate the use of the application. Three categories of animals have been defined following their position in water. The mean error of automatic counts compared with manual delineations is +2.3% and shows that the estimation is unbiased. Those results show great perspectives for the use of the algorithm in populations monitoring after some technical improvements and the elaboration of statistically robust inventories protocols.

The exergy of a phase shift: Ecosystem functioning loss in seagrass meadows of the Mediterranean Sea

Sustained functioning of ecosystems is predicted to depend upon the maintenance of their biodiversity, structure and integrity. The large consensus achieved in this regard, however, faces to the objective difficulty of finding appropriate metrics to measure ecosystem functioning. Here, we aim at evaluating functional consequence of the phase shift occurring in meadows of the Mediterranean seagrass Posidonia oceanica, a priority habitat that is undergoing regression in many coastal areas due to multiple human pressures. Structural degradation of the P. oceanica ecosystem, consequent to increasing coastal exploitation and climate change, may result in the progressive replacement of this seagrass by opportunistic macrophytes, either native or alien. Reviewing published information and our personal records, we measured changes in biological habitat provisioning, species richness and biomass associated to each of the alternative states characterizing the phase shift. Then, ecosystem functioning was assessed by computing the exergy associated to each state, exergy being a state variable that measures the ecosystem capacity to produce work. Phase shift was consistently shown to imply loss in habitat provision, species richness, and biomass; structural and compositional loss was parallelled by a reduction of exergy content, thus providing for the first time an objective and integrative measure of the loss of ecosystem functioning following the degradation of healthy seagrass meadows.

A new fish-based multi-metric assessment index for cyprinid streams in the Iranian Caspian Sea Basin.

A major issue for water resource management is the assessment of environmental degradation of lotic ecosystems. The overall aim of this study is to develop a multi-metric fish index for the cyprinid streams of the Caspian Sea Basin (MMICS) in Iran. As species diversity and composition as well as population structure in the studied streams are different to other regions, there is a substantial need to develop a new fish index. We sampled fish and environmental data of 102 sites in medium sized streams. We analysed human pressures at different spatial scales and determined applicable fish metrics showing a response to human pressures. In total, five structural and functional types of metrics (i.e. biodiversity, habitat, reproduction, trophic level and water quality sensitivity) were considered. In addition, we used 29 criteria describing major anthropogenic human pressures at sampling sites and generated a regional pressure index (RPI) that accounted for potential effects of multiple human pressures.For the MMICS development, we first defined reference sites (least disturbed) and secondly quantified differences of fish metrics between reference and impaired sites. We used a Generalised Linear Model (GLM) to describe metric responses to natural environmental differences in least disturbed conditions. By including impaired sites, the residual distributions of these models described the response range of each metric to human pressures, independently of natural environmental influence.Finally, seven fish metrics showed the best ability to discriminate between impaired and reference sites. The multi-metric fish index performed well in discriminating human pressure classes, giving a significant negative linear response to a gradient of the RPI. These methods can be used for further development of a standardised monitoring tool to assess the ecological status and trends in biological condition for streams of the whole country, considering its complex and diverse geology and climate.

Linking risk factors to risk treatment in ecological risk assessment of marine biodiversity

Abstract Implementing marine ecosystem-based management at regional and small spatial scales is challenging due to the complexity of ecosystems, human activities, their interactions and multilayered governance. Ecological risk assessments (ERAs) of marine biodiversity are often used to prioirtise issues but only give broad guidance of how issues might be addressed in the form of strategies. However, at small and regional spatial scales marine natural resource managers have to make decisions within these strategies about how to manage specific interactions between human uses and ecological components. By using the transition between risk characterization and risk treatment in ERA for marine biodiversity tractable ways through the complexity can be found. This paper will argue that specific management and research actions relevant to smaller spatial scales can be developed by using the linkage between risk factors and risk treatment in ERA. Many risk factors require risk treatments that extend beyond the boundary of local agencies or sector responsibilities. The risk factor-treatment platform provides a practical way that these boundaries can be opened up by providing a scientifically based and transparent process to engage all actors who need to be involved in addressing the issues raised by an ERA. First, the principles of the mechanism will be described. Second, how the mechanism is constructed will be introduced using examples from an urban estuary. Application of the mechanism reveals three different types of risk factors (stressor, ecological, and knowledge gap) that can be used to develop specific management and research actions to treat risks. The systematic approach enables the dual complexities of marine ecosystems and multiple human pressures to be unravelled to identify and target issues effectively. The risk factor treatment linkage provides a platform to negotiate and develop effective management and research actions across jurisdictional, disciplinary, community and stakeholder boundaries.

A global model of the response of tropical and sub-tropical forest biodiversity to anthropogenic pressures.

Habitat loss and degradation, driven largely by agricultural expansion and intensification, present the greatest immediate threat to biodiversity. Tropical forests harbour among the highest levels of terrestrial species diversity and are likely to experience rapid land-use change in the coming decades. Synthetic analyses of observed responses of species are useful for quantifying how land use affects biodiversity and for predicting outcomes under land-use scenarios. Previous applications of this approach have typically focused on individual taxonomic groups, analysing the average response of the whole community to changes in land use. Here, we incorporate quantitative remotely sensed data about habitats in, to our knowledge, the first worldwide synthetic analysis of how individual species in four major taxonomic groups—invertebrates, ‘herptiles’ (reptiles and amphibians), mammals and birds—respond to multiple human pressures in tropical and sub-tropical forests. We show significant independent impacts of land use, human vegetation offtake, forest cover and human population density on both occurrence and abundance of species, highlighting the value of analysing multiple explanatory variables simultaneously. Responses differ among the four groups considered, and—within birds and mammals—between habitat specialists and habitat generalists and between narrow-ranged and wide-ranged species.

Assessing benthic health under multiple human pressures in Bohai Bay (China), using density and biomass in calculating AMBI and M‐AMBI

AbstractIn recent decades, China has undergone an impressive development, which has produced increasing human pressures including coastal degradation. Bohai Bay, located in the west of the Bohai Sea (north of China), has been affected by various human pressures, including waste water discharges, land reclamation and oil exploitation. To monitor the effects of these pressures on this ecosystem, benthic macroinvertebrates and environmental variables (dissolved oxygen, nutrients, metals, etc.) were sampled in 2009 and 2011. To assess the ecological status of the benthic communities, the AZTI Marine Biotic Index (AMBI) and multivariate‐AMBI (M‐AMBI) were used, including both density and biomass in the calculation. This is the first research in which M‐AMBI based on biomass (M‐bAMBI) is applied. Both methods showed that the nearshore areas, especially close to the Haihe and Jiyun estuaries, were affected by human pressures, with a clear gradient of decreasing impacts offshore. The ecological status as assessed using density and biomass was quite similar. Significant relationships were also found between both methods and environmental variables. The use of AMBI and M‐AMBI, based upon density and biomass, in assessing the ecological status of water bodies in China seems to be promising.

Multiple human pressures and their spatial patterns in European running waters.

Running water ecosystems of Europe are affected by various human pressures. However, little is known about the prevalence, spatial patterns, interactions with natural environment and co-occurrence of pressures. This study represents the first high-resolution data analysis of human pressures at the European scale, where important pressure criteria for 9330 sampling sites in 14 European countries were analysed. We identified 15 criteria describing major anthropogenic degradation and combined these into a global pressure index by taking additive effects of multiple pressures into account. Rivers are affected by alterations of water quality (59%), hydrology (41%) and morphology (38%). Connectivity is disrupted at the catchment level in 85% and 35% at the river segment level. Approximately 31% of all sites are affected by one, 29% by two, 28% by three and 12% by four pressure groups; only 21% are unaffected. In total, 47% of the sites are multi-impacted. Approximately 90% of lowland rivers are impacted by a combination of all four pressure groups.

Understanding relationships between conflicting human uses and coastal ecosystems status: A geospatial modeling approach

Human use of ecosystem resources and services is increasing worldwide, generating pressures that alter ecosystem structure, functioning and provision of services. Unexpected ecosystem change is becoming frequent, and the complex ways through which multiple human pressures may interact leave conservation practitioners and natural resource managers faced with high uncertainty. We developed a geospatial approach for modeling the complex relationships between multiple human pressures and coastal ecosystems status. This framework was then used to produce maps of the expected status of marine coastal ecosystems resulting from variation in the cumulative human pressure. The geospatial modeling approach we developed was tested on an emblematic study case requiring marine spatial planning, i.e. a recently established marine protected area (MPA) that will have to coexist with the expansion of a close commercial harbor. In the study case presented, our modeling approach was used to predict the status of coastal ecosystems resulting from different management alternatives. Results showed that should Port Authority support MPA in reducing human pressures in the area, coastal ecosystems would not be expected to further deteriorate as a consequence of harbor expansion. Our approach proved effective in modeling complex interaction among multiple pressures (e.g. synergisms) and predicting potential future scenarios. The implementation of this approach into geographical information systems (GIS) allows managers to represent the expected outcomes of their planned conservation efforts, thereby representing an important decision-support tool for finding efficient management solutions in the face of complex interactions and high uncertainty.

Significant variables for the conservation of mountain invertebrates

Conserving biodiversity on mountains holds particular challenges, with topographic species beta diversity being high. In turn, conserving mountain biodiversity in the heart of a biodiversity hotspot, with intense urbanization on its lower slopes, poses further challenges. We investigate here an iconic mountain at the southern tip of Africa, which is under multiple human pressures, while receiving much conservation attention. We sought here some general principles to guide conservation management of this and other similar mountains. Our focal organisms were surface-active invertebrates, as they are abundant, diverse, and environmentally sensitive at point localities. We show that vegetation structure and elevation were the most important environmental variables determining this diversity. Type of fynbos vegetation, proximity of forest to a river, aspect, and abundance of the alien Argentine ant Linepithema humile, had no significant influence. Suburban woodland species richness and abundance had a non-significant difference to that of natural forest. Fynbos had high species beta diversity of invertebrates, suggesting that large areas of this dominant vegetation type should be conserved. However, many specialist and highly local endemic species were in forest, highlighting the irreplaceability of forest habitats. Such a mountain, with its complex topography, requires total protection, as there is no room for loss of any part of the mountain. We emphasize that, while the upper slope and summit are well protected, the lower slopes are in need of urgent attention, a situation which mirrors that in Europe.