Conservation Value Index Research Articles

Phylogenetic diversity in conservation: A brief history, critical overview, and challenges to progress

AbstractSpecies that are evolutionarily distinct have long been valued for their unique and irreplaceable contribution to biodiversity. About 30 years ago, this idea was extended to the concept of phylogenetic diversity (PD): a quantitative, continuous-scale index of conservation value for a set of species, calculated by summing the phylogenetic branch lengths that connect them. This way of capturing evolutionary history has opened new opportunities for analysis, and has therefore generated a huge academic literature, but to date has had only limited impact on conservation practice or policy. In this review, I present a brief historical overview of PD research. I then examine the empirical evidence for the primary rationale of PD that it is the best proxy for “feature diversity,” which includes both known and unknown phenotypic characters, contributing to utilitarian value, ecosystem function, future resilience, and evolutionary potential. Surprisingly, it is only relatively recently that this rationale has been subject to systematic empirical scrutiny, and to date, there are mixed results on the connection between PD and phenotypic diversity. Finally, I examine the least well-studied, but potentially greatest challenge for PD: its dependence on the reliability of phylogenetic inference itself. The very few studies that have investigated this so far show that the ranking of species assemblages by their PD values can vary substantially under alternative, routine, phylogenetic methods and assumptions. If PD is to become more widely adopted into conservation decision-making, it will be important to better understand the conditions under which it performs well, and those under which it performs poorly.

Avian Diversity and Seasonal Abundance in Banpale Forest, Kaski District, Nepal

Baseline information on bird diversity is essential for biodiversity monitoring and conservation as birds are often considered a key indicator of ecosystem health and ecological balance. Studies from other countries suggest that green patches, like university campuses, play a vital role in local bird conservation in urbanized regions. In the Kaski district of Nepal, the study of bird diversity is limited to the larger lakes of the Pokhara valley. Banpale Forest, one of the few green patches in the Pokhara valley, is considered a hotspot for birdwatching; however, no proper studies have been conducted to explore the bird diversity. This study examines the species diversity and seasonal abundance of birds in the Banpale Forest of the Institute of Forestry, Pokhara. Two trails built by villagers and students for walking were used as transects for the study. A total of 2,975 bird individuals of 125 species were counted in the survey conducted from June 2018 to May 2019, with 12 field visits along a 2.17km trail. Passeriformes (54.03%) and Accipitridae (13.71%) were the dominant order and family respectively among the recorded species. Species diversity (H’) was higher in the winter season (H’=3.99), with species richness of 13.26 and species evenness of 0.88. Insectivores (n=54) were the dominant foraging guilds among the recorded species. The high avifaunal diversity and conservation value index of Banpale Forest indicate the need for conservation planning in the region.

Longitudinal multidiversity pattern and the environmental drivers of riparian bird communities along submontane rivers of Changbai Mountains, China.

Riparian zones are biodiversity hotspots in montane ecosystems and are of critical conservation concern. However, studies on longitudinal diversity patterns and environmental drivers have been restricted to aquatic fauna, while the animals that rely on both river and riparian resources have been of much less concern. Here, we examined the multifaceted diversity distribution of riparian birds along longitudinal gradients and analyzed the importance of environmental factors in shaping these patterns in the Changbai Mountains. Hump-shaped relationships between elevation and taxonomic, phylogenetic, and functional diversity, as well as with the conservation value index, were evident along each of the classic submontane rivers. Forest cover, vegetation height variation, and land cover patches positively affected the taxonomic diversity indices. In addition to the species richness, fluvial geomorphology variables (river sinuosity and gravel bar) were significantly related to the phylogenetic diversity. However, there was no statistical evidence for a relationship between functional diversity and the environmental variables examined. This study emphasized the necessity of including multiple diversity measures beyond taxonomic diversity and demonstrated the importance of both terrestrial and aquatic components in shaping the multifaceted biodiversity pattern of riparian organisms living in riparian zones. The results suggested that conservation priority should be given to both rivers and banks in the middle reaches and that riparian birds could be good candidate indicators of environmental change in the submontane river-forest ecotone.

Una propuesta para valorar el estado de conservación de los bordes de caminos rurales en el sudeste bonaerense

Rural roadsides (RRS) are key elements for conserving biodiversity and ecosystem services in agricultural landscapes. Their restoration and management require simple protocols to assess (diagnose) their conservation status and ecological functionality. We elaborated a conservation value index (CVI) of RRS by constructing a decision tree based on the experts’ opinion. The index, which can range between 4 and 30, evaluates the conservation status and ecological functionality of RRS according to 11 attributes related to vegetation structure. The CVI was applied to 30 RRS in southeastern Buenos Aires (Argentina). Values ranged from 4 to 29, being the cropped RRS those with the lowest value. The RRS with the highest CVI (>21) were those characterized by higher richness of native, entomophily and cultural value species, higher coverage of native species and perennial grasses, lower coverage of weeds and invasive species, and presence of at least a vulnerable and/or phytotelmata species. This index represents a first contribution applicable to the diagnosis of the conservation status of RRS through the identification of key attributes of vegetation structure suggested by experts. In addition, the index provides relatively synthetic information about the status of RRS, which in spite of their multiple ecological functions are seldom taken into account for their conservation within territorial planning. DOI: https://doi.org/10.25260/EA.17.27.3.0.541

Forest edges have high conservation value for bird communities in mosaic landscapes.

A major conservation challenge in mosaic landscapes is to understand how trait‐specific responses to habitat edges affect bird communities, including potential cascading effects on bird functions providing ecosystem services to forests, such as pest control. Here, we examined how bird species richness, abundance and community composition varied from interior forest habitats and their edges into adjacent open habitats, within a multi‐regional sampling scheme. We further analyzed variations in Conservation Value Index (CVI), Community Specialization Index (CSI) and functional traits across the forest‐edge‐open habitat gradient. Bird species richness, total abundance and CVI were significantly higher at forest edges while CSI peaked at interior open habitats, i.e., furthest from forest edge. In addition, there were important variations in trait‐ and species‐specific responses to forest edges among bird communities. Positive responses to forest edges were found for several forest bird species with unfavorable conservation status. These species were in general insectivores, understorey gleaners, cavity nesters and long‐distance migrants, all traits that displayed higher abundance at forest edges than in forest interiors or adjacent open habitats. Furthermore, consistently with predictions, negative edge effects were recorded in some forest specialist birds and in most open‐habitat birds, showing increasing densities from edges to interior habitats. We thus suggest that increasing landscape‐scale habitat complexity would be beneficial to declining species living in mosaic landscapes combining small woodlands and open habitats. Edge effects between forests and adjacent open habitats may also favor bird functional guilds providing valuable ecosystem services to forests in longstanding fragmented landscapes.

The impact of natural resource use on bird and reptile communities within multiple-use protected areas: evidence from sub-arid Southern Madagascar

Multiple-use protected areas, in which sustainable levels of extractive livelihood activities are permitted, play an increasingly important role in the global protected area estate, and are expected to rise in prevalence. However, we know little about their effectiveness at conserving biodiversity. We surveyed bird and reptile communities in three areas across a forest disturbance gradient resulting from charcoal production and shifting cultivation within a multiple-use protected area in Madagascar’s sub-arid spiny forest. We scored individual species using a Conservation Value Index (CVI; a simple metric based on rarity, threat and distinctiveness), and estimated the total conservation value of each treatment by calculating the sum of frequency-weighted CVI scores across all present species. Bird and reptile community responses to forest disturbance were idiosyncratic. Bird richness was greatest in the moderate-disturbance treatment, but the low-disturbance treatment had the superior conservation value due to higher frequencies of locally-endemic species. Reptile richness was the same in low- and moderate-disturbance treatments, but the conservation value of the latter was greater. The high-disturbance areas had lowest richness and conservation value for both groups. For birds, increasing disturbance levels were accompanied by community turnover from high-value to low-value species, a pattern highlighted by CVI that is masked by assessing species richness alone. Although some endemic species appear to be resilient to degradation, multiple-use protected areas in Madagascar may lose biodiversity since most endemic species are forest-dependent. Stricter protected area models may be more appropriate in areas where much of the high-value biodiversity is sensitive to habitat degradation.

Assessing Potential Conservation and Restoration Areas of FreshwaterFish Fauna in the Indian River Basins.

Conservation efforts globally are skewed toward terrestrial ecosystems. To date, conservation of aquatic ecosystems, in particular fish fauna, is largely neglected. We provide a country-wide assessment of Indian river ecosystems in order to identify and prioritize areas for protection and restoration of freshwater fish fauna. Using various biodiversity and anthropogenic attributes, coupled with tools of ecological modeling, we delineated areas for fish fauna conservation and restoration in the 20 major river basins of India. To do this, we used prioritization analyses and reserve selection algorithms to derive conservation value index (CVI) and vulnerability index (VI) of the river basins. CVI was estimated using endemicity, rarity, conservation value, and taxonomic singularity, while VI was estimated using a disturbance index derived from percent geographic area of the basin under human settlements, human population density, predominant land use, and total number of exotic fish species in each basin. The two indices, CVI and VI, were converted into geo-referenced maps, and each map was super-imposed onto species richness and forest cover maps, respectively. After superimposition, areas with high CVI and low VI shade intensities were delineated for conservation, while areas with high CVI and high VI shade intensities were demarcated for restoration. In view of the importance of freshwater fish for human livelihoods and consumption, and ecosystems of India's rivers, we call for urgent attention to the conservation of their fish fauna along with restoration of their degraded habitats.

Does the taxonomic completeness of headwater stream assemblages reflect the conservation status of the riparian forest?

Headwater streams are intimately linked to their riparian zones, yet in conservation planning streams have attracted much less attention than riparian forests. We assessed the relation between the conservation status of riparian forests and taxonomic completeness (ratio of observed to expected taxa richness, O/E) of stream bryophytes and benthic invertebrates in fifty northern Finnish headwater streams. The streams represent three levels of riparian modification: pristine old-growth forests (Woodland Key Habitats, WKHs), slightly modified and strongly modified (mainly drainage ditching) forests. Macroinvertebrate O/E ratios were significantly, by about 40%, higher in natural than in modified sites. Bryophyte O/E ratios in strongly modified sites were about half of those in pristine sites (mean O/Es: 0.95 vs. 0.50, respectively) whereas the pristine and slightly modified sites did not differ. O/E ratios of both groups were negatively correlated with fine sediments, indicating drainage as the primary factor impairing stream condition. Eight streams (four pristine, four slightly modified) monitored through six years showed little temporal variability in taxonomic completeness. Nonetheless, inter-annual variability in O/E was sufficient to cause frequent misclassifications of stream status, slightly modified sites being frequently classified as no different from the reference. For macroinvertebrates, sites indicative of high conservation value (CV) were rather evenly distributed among the three status classes, whereas the bryophyte CV index was lower for the strongly modified than for pristine sites. Several sites defined degraded a priori scored high values for the CV index of macroinvertebrates. Conservation efforts focusing on small-scale key habitats may therefore be insufficient and need to be complemented by sites that remain beyond protected area networks (WKHs), yet support high conservation value in terms of rare taxa occurrence. Conclusions about the performance of protected area networks should not be based on a single taxonomic group as different groups may yield different assessment outcomes. We also suggest that sites that are in inferior ecological condition (O/E<1.0) yet support unexpectedly high numbers of rare taxa (CV>1.0) should be addressed as ‘restoration priority sites’ that might benefit from in-stream or riparian (or both) restoration.

Identifying Priority Areas for Conservation and Management in Diverse Tropical Forests

The high concentration of the world’s species in tropical forests endows these systems with particular importance for retaining global biodiversity, yet it also presents significant challenges for ecology and conservation science. The vast number of rare and yet to be discovered species restricts the applicability of species-level modelling for tropical forests, while the capacity of community classification approaches to identify priorities for conservation and management is also limited. Here we assessed the degree to which macroecological modelling can overcome shortfalls in our knowledge of biodiversity in tropical forests and help identify priority areas for their conservation and management. We used 527 plant community survey plots in the Australian Wet Tropics to generate models and predictions of species richness, compositional dissimilarity, and community composition for all the 4,313 vascular plant species recorded across the region (>1.3 million communities (grid cells)). We then applied these predictions to identify areas of tropical forest likely to contain the greatest concentration of species, rare species, endemic species and primitive angiosperm families. Synthesising these alternative attributes of diversity into a single index of conservation value, we identified two areas within the Australian wet tropics that should be a high priority for future conservation actions: the Atherton Tablelands and Daintree rainforest. Our findings demonstrate the value of macroecological modelling in identifying priority areas for conservation and management actions within highly diverse systems, such as tropical forests.

Similar effects of residential and non-residential vegetation on bird diversity in suburban neighbourhoods

Estimating the relative importance of vegetation on residential land (gardens, yards, and street-trees) and vegetation on non-residential land (parks and other large green spaces) is important so that competing options for urban conservation planning can be prioritized. We used data from an urban breeding-bird monitoring program to compare the relative effects vegetation on residential land and vegetation on non-residential land (both the amount and type of vegetation at local and landscape scales) on bird species richness and an index of conservation value for the bird community. We then estimated the realised relative benefit of managing the amount of vegetation on these two types of land (i.e., as alternative management options for promoting biodiversity), which might be achieved within the practical limits imposed by human population density. The local effects of increasing residential and non-residential vegetation amount were similar and positive on all measures of bird species richness and conservation value. Non-residential vegetation had an additional landscape-scale influence on bird diversity that residential vegetation did not. Options for managing the amount of non-residential vegetation appear to be more limited by high human population density than for managing the amount of residential vegetation. This suggests that there may be greater realised benefits to bird diversity from managing the amount of vegetation on residential land than from the more common focus of urban planning of managing vegetation on non-residential land.

湿地自然保护区保护价值评价方法

Wetland nature reserves are one of the main networks of China′s nature reserves system.A protection management system is gradually taking shape.However,the current system of wetland nature reserves was established based on the idea of saving and preserving specific natural wetland areas,a method which lacked a reasonable level of system-wide oversight and planning.The system used to establish nature reserves lacked an effective assessment methodology to help provide for the management,planning and delineation of the wetland nature reserves in China.Therefore,one prerequisite involved in reforming this system was to develop a logical and workable method of evaluating wetland nature reserves which focused on the planning,establishment,and management of those reserves. Wetland birds are important indicator species and the presence or absence of wetland bird species has been used as an important standard to justify upgrading the status of nature reserves.Wetland nature reserves established for these waterbirds provide good habitat and food sources as well as breeding,migration and overwintering areas.We present here a wetland nature reserve evaluation method based on a thorough analysis of the existing wetland nature reserve system using waterbird information and geographical/ecological information with a focus on waterbird protection.It may be used to evaluate the existing different administrative levels of the wetland nature reserve system. An evaluation index system is proposed for wetland nature reserves based on scientific research and planning information related to wetland nature reserves.The indicators of this index system were identified by consultation with experts and the use of conferences;a hierarchical model was established using the analytic hierarchy process(AHP).The four tiered index system consisted of 1 object layer,5 system layers,11 criteria layers and 26 index layers.The nature reserves were classified into three broad types based on relevant national criterion to facilitate the analysis of this application and evaluation method,1) nature reserve for ocean and seacoast ecosystem,2)nature reserve for inland wetlands and water area ecosystem,and 3) nature reserve for wildlife types.The three wetland types within the nature reserve wetland system were further divided into four smaller types 1) offshore and coastal wetlands,2) riverine,3)lacustrine wetlands,and 4) marsh wetlands. Meanwhile,the Golden section method was used to assign indicators.Each set of indicators was calculated using frequency percentiles,with the values of 62%,38%,and 0% representing the high,medium,low value by threshold,respectively.The assignment method was(62%—100%) as the high value niche section assignment 1,(38%—62%) as interval assignment 0.62,and(0—38%) as low range assignment 0.38.The final results were calculated from the nature reserve conservation value index formula. In this paper,8 nature reserves were analyzed from the offshore and coastal wetlands as the main body of ocean and seacoast ecosystem type,13 nature reserves of marsh wetlands were analyzed as the main body of inland wetlands and water area ecosystem type and 6 nature reserves of riverine wetlands were analyzed as the main body of wildlife type and classified for each type of protection index on a case-by-case basis,respectively. The results showed the evaluation method used to classify wetlands on the basis of waterbird protection may objectively and fairly reflect the value of wetlands needed to protect water birds.Furthermore,this evaluation index system may be used to classify the wetland nature reserve system using a protection index and provides the foundation to plan and reconstruct the wetland ecosystem nature reserves and change their protection status.

Sandy beach conservation and recreation: Guidelines for optimising management strategies for multi-purpose use

This paper addresses the need for a simple model for managers to employ when planning strategies for management of sandy beaches. It is based on the premise that in the overwhelming majority of cases beaches are suitable for recreation or for conservation or a combination of the two, whereas other uses are rare. The broad range of physical, ecological and socio-economic factors relevant to beaches, are reviewed briefly. Then three key factors are selected to develop each of two simple indices, an index of conservation value, CI, based on dune state of health, the presence of iconic species and macrobenthic species richness; and an index of recreation potential, RI, based on the extent of infrastructure, the level of safety/health of the beach and its physical carrying capacity. By combining these two indices, a beach can be simply classified as suitable for intensive recreation, or primarily for conservation, or for mixed use. Ten principles are outlined for consideration and potential application to beach management strategies. Finally, 23 beaches from three continents are classified, with detailed descriptions of a beach typical of each major use type.

The comparison of site spider “biodiversity quality” in Portuguese protected areas

Spiders at 23 Portuguese protected area sites were sampled (pitfall trapped) over 10-month periods. The data allowed for a “biodiversity quality” assessment consisting of the following indices: Species Richness, Biomass, Simpson Index, Species Conservation Value Index and Population Density. These “biodiversity quality” characteristics were reviewed for relative indication of site spider “biodiversity quality”. Spiders are proposed as a group of organisms that could be used to indicate part of the “biodiversity quality” of a site since they can be sampled in a standardised way and yield biodiversity indices for comparison spatially and temporally. The approach adopted in this paper allows a range of “biodiversity quality” indices to be measured for spiders in Portuguese protected areas which, in turn requires decisions from scientists, managers and politicians on what element or characteristic of biodiversity it is intended to be targeted.

Does Botanical Diversity in Sewage Treatment Reed-Bed Sites Enhance Invertebrate Biodiversity?

(1) This study examines the effect of increasing botanical diversity, through reed-bed planting and maintenance regimes, on sewage treatment reed-bed invertebrate biodiversity and the possible enrichment of overall catchment biodiversity. (2) Reed-bed invertebrates were identified as a good indicator group of overall site biodiversity quality and were sampled at a range of sewage treatment reed-bed sites in the same geographical area between May and August 2006 (plus one natural reed-bed control site). Standardised water trapping and pitfall trapping techniques were employed throughout this sampling period. (3) Statistical analysis of the sampling results revealed that the number of plant species recorded was inversely related to terrestrial invertebrate species richness, species conservation value index and biomass within the study sites. For example, the natural reed-bed sampled had the highest botanical diversity but the lowest terrestrial invertebrate species richness. (4) This study has demonstrated that sewage treatment reed-beds support a diverse range of invertebrate species, some of them being of national conservation value. This suggests that sewage treatment reed-beds may be at least as biodiverse as naturally occurring reed-beds and will add to the overall biodiversity and ecohydrology of a catchment whilst saving energy.

Bird community specialization, bird conservation and disturbance: the role of wildfires

1. Although niche theory predicts that disturbance should favour generalist species, the community-level implications of this pattern have been sparsely analysed. Here, we test the hypothesis that disturbance favours generalist species within communities, analysing effects of wildfires in bird communities in a Mediterranean climate area as a case study. 2. We use bird occurrence data in more than 500 1 × 1 km squares forming a gradient running from forest to completely burnt areas. The level of specialization of bird communities was estimated by means of three complementary species specialization indices, calculated for different landscape gradients and averaged at the community level (i.e. 1 × 1 km squares), and mean species rarity. 3. We also calculated mean habitat preferences along landscape gradients, as well as an index of conservation value and total species richness. 4. Different estimators of bird community specialization varied in contrasting fashion along the wildfire disturbance gradient, and thus we conclude that it is not justified to expect unique community responses to the sharp variations in habitat characteristics brought by wildfire disturbances. 5. Burnt areas tended to have rarer and urban-avoider bird species, whereas unburnt forests tended to have larger proportions of forest specialist species. 6. The mean conservation value of communities clearly increased towards the burnt extreme of the wildfire disturbance gradient, while this had a negligible effect on species richness. 7. Wildfires seem to play an important role for the maintenance of open-habitat, urban-avoider bird populations in Mediterranean landscapes and also to benefit a set of bird species of unfavourable European conservation status. 8. In this context, it cannot be unambiguously concluded that fire disturbance, even in a context in which fires are greatly favoured by human-related activities, leads to more functionally simplified communities dominated by generalist species.

Conservation Value and Degree of Threat of Natural Habitats—An Attempt for Evaluation Matrix

ABSTRACTThe main problem of developing an evaluation matrix is the transformation of “quality” parameters into “quantity” parameters. Based on our previous experience an attempt for elaboration of evaluation matrix for natural habitats was made. A four level scale of 25, 50, 75 to 100 relative units gives the possibility to measure the conservation value and degree of threat. Several types of parameters were used for evaluation: spatial, temporal and functional. The occurrence of species with conservation value in the habitats and specie' presence in national and international legislation was taken into account. The most significant condition for the effective use of the matrix is the sufficient knowledge about the habitats and threats selected for evaluation. Corresponding with the IUCN categories, four degrees of the Index of Threat were accepted: CRh—Critically Endangered; ENh—Endangered; VUh—Vulnerable; NTh—Near Threatened, where the letter “h” indicates “habitat”. Four degrees of the Index of Conservation Value were accepted: HSh—Highly Significant; CSh—Conservation Significant; LSh—Least Significant; NSh—Non Significant.

Assessing the conservation value of the spider fauna across the West Palearctic area

Making use of the recent publication of a catalogue of spider species from Europe and the Mediterranean Basin, we built a computer database which indexes all specific and subspecific taxa reported from countries or islands in Platnick's world catalogue as well as in regional or national catalogues. We used this database to analyze the distribution of conservation values at the West Palearctic scale. Three indices of conservation value were calculated and compared between mainland and island territories: species richness, number of endemic species, and Ic, a “Conservation Value Index.” Species richness increases with the size of the area being considered, either in islands or in mainland countries, and is highest in Southern Europe. The number of endemics also increases with area, but only for mainland countries, suggesting that different factors determine endemism on islands and in mainland areas. The conservation index shows that several island territories are of a high conservation interest: the Mediterranean and Atlantic islands clearly exhibit the highest conservation value and some islands (mainly Canary and Balearic islands) can be considered hotspots of biodiversity for the West Palearctic area; other hotspots are some small Mediterranean islands.

Análisis de la riqueza vegetal y el valor de conservación de tres áreas incorporadas a la Reserva Ecológica del Pedregal de San Ángel, Distrito Federal (México)

Se evaluó la riqueza vegetal y el valor de conservación de tres zonas incorporadas recientemente a la Reserva Ecológica del Pedregal de San Ángel: dos añadidas a la zona núcleo suroriente (SO 1 y S02) y el área de amortiguamiento A13. Se registraron 199 especies (57.6% de las reportadas). Se registraron 148, 152 y 149 especies en SOi, S02 y A13, respectivamente. En Al3 se registró a Mammillaria haageana subsp. san-angelensis, una subespecie en peligro de extinción, a Bletia urbana, clasificada como amenazada, y a dos nuevos registros para la reserva: Eupatorium pazcuarense y Adiantum andicola. Se reconoce también a Pennisetum clandestinum, por lo que se eleva a 340 especies el número de especies registradas en esta reserva. Utilizando un índice de valor para la conservación basado en ocho parámetros, se encontró que el sitio Al3 tiene mayor valor (21 puntos), seguido por el S02 y SO 1, con 16.5 y 10.5 puntos, respectivamente.

Average optimacity: An index to guide site prioritization for biodiversity conservation

We developed an index, called average optimacity, that can be used to guide site prioritization for biodiversity conservation. Our index has three desirable properties: (1) it indicates a site’s potential contribution to an efficient representative reserve system; (2) it equals zero if and only if a site contains no elements of biodiversity; and (3) it accommodates multiple sets of representation targets. The index is calculated with an optimization algorithm – simulated annealing as implemented in the computer program Marxan. We ran Marxan with 10 different representation target sets and averaged the results. The 10 target sets approximated equal increments in conservation value. Data from the Willamette Valley-Puget Sound-Georgia Basin Ecoregion were used to evaluate the index. To help conservation planners understand average optimacity we: (1) compared it to an average of irreplaceability, a well-known index of conservation value, and (2) used logistic regression models to relate average optimacity to other measures of conservation value (e.g., rarity, richness). Average optimacity and average irreplaceability were highly correlated (Spearman rank correlation=0.90), suggesting substantial agreement in site prioritization. However, there were clear differences in the rankings of highly valued sites, demonstrating that these two indices provide different perspectives on priorities. Simple regression models showed that average optimacity was strongly associated with maximum representation and maximum rarity. Two of the top multiple regression models for average optimacity exhibited a moderate increase in explanatory power relative to the best simple regression model and had three independent variables, which reflects the multi-dimensional nature of this index. The average optimacity index may be preferable to an irreplaceability index when efficiency is considered an important dimension for site prioritization.

Prioritization of fish assemblages with a view to conservation and restoration on a large scale European basin, the Loire (France)

The hierarchical organization of important sites for the conservation or the restoration of fish communities is a great challenge for managers, especially because of financial or time constraints. In this perspective, we developed a methodology, which is easy to implement in different locations. Based on the fish assemblage characteristics of the Loire basin (France), we created a synthetic conservation value index including the rarity, the conservation status and the species origin. The relationship between this new synthetic index and the Fish-Based Index allowed us to establish a classification protocol of the sites along the Loire including fish assemblages to be restored or conserved. Sites presenting disturbed fish assemblages, a low rarity index, few threatened species, and a high proportion of non-native species were considered as important for the restoration of fish biodiversity. These sites were found mainly in areas where the assemblages are typical of the bream zone, e.g. with a higher number of eurytopic and limnophilic species. On the contrary, important sites for conservation were defined as having an important conservation potential (high RI, a lot of threatened species, and few non-natives fish species) and an undisturbed fish assemblage similar to the expected community if habitats are undisturbed. Important sites for conservation were found in the Loire basin’s medium reaches which host assemblages typical for the grayling and the barbell zones, e.g. with a higher number of rheophilic species. The synthetic conservation value index could be adapted and completed with other criteria according to management priorities and capacities.