The coincidence of people and biodiversity in Europe

A positive correlation between human population density and species richness has been recorded across the tropics. Here I investigate whether this correlation holds true for Europe. Analyses reveal a positive correlation between human population density and plant (rho = 0.505), mammal (rho = 0.471) and reptile and amphibian (rho = 0.556) species richness. The results are largely concordant with those obtained in similar studies for Africa. However, contrary to previous analyses, the correlation found between people and breeding bird species richness (rho = 0.186) was weak. Of three measures of endemism used, only combined European endemic species richness correlated with human density (rho = 0.437). Richness among combined restricted‐range European endemics was not correlated (rho = 0.095) with human density, while richness among all combined restricted‐range species was only weakly correlated with human density (rho = 0.167). The results partially support the idea of a correlation between people and biodiversity, although there are some important exceptions. Discussion of possible mechanisms underling the observed patterns is undertaken.     

Priorities for conserving global species richness and endemism

The Convention on Biological Diversity aims to encourage and enable countries to conserve biological diversity, to use its components sustainably and to share benefits equitably. Species richness and endemism are two key attributes of biodiversity that reflect the complexity and uniqueness of natural ecosystems. National data on vertebrates and higher plants indicate global concentrations of biodiversity and can assist in defining priorities for action. Projections indicate that species and ecosystems will be at maximum risk from human activities during the next few decades. Prompt action by the world community can minimise the eventual loss of species. Highest priorities should be to: (i) strengthen the management of ecosystems containing a large proportion of global biodiversity; (ii) help developing countries complete their biodiversity strategies and action plans, monitor their own biodiversity, and establish and maintain adequate national systems of conservation areas; (iii) support actions at the global level, providing benefit to all countries in managing their own biodiversity. Generally, resources will best be spent in safeguarding ecosystems and habitats that are viable and important for global biodiversity, and which are threatened by factors that can be controlled cost-effectively. Other important criteria are representativeness, complementarity and insurance.     

Bird biodiversity

Endemic Bird Areas of the World. Priorities for Biodiversity Conservation by A.J. Stattersfield, M.J. Crosby, A.J. Long and D.C. Wege, Birdlife International, 1997. £37.00 pbk (860 pages) ISBN 0946 888 33 7CDROM: Birds of the World—A Multimedia Encyclopedia, Ransom, 1997. £14.99 ISBN 1 863 89 1748     

Searching for heat in a marine biodiversity hotspot

Coral reefs exhibit highly congruent patterns of biodiversity, with a prominent hotspot in the Indo-Australian Archipelago (IAA). Unlike many terrestrial systems, the IAA hotspot exhibits extensive latitudinal and longitudinal biodiversity gradients. Conflicting hypotheses have highlighted the importance of the area as a centre of origin, overlap or accumulation, with the location of endemics being used as the primary criterion for testing these hypotheses, by identifying the presumed geographical origins of species. We evaluate the utility of marine endemics for resolving these hypotheses, and examine recent molecular phylogenetic evidence for coral reef species that has revealed the antiquity of the endemics and the other species that make up this hotspot. These analyses emphasize the importance of the IAA in the survival rather than the origins of species.     

Assessing endemism at multiple spatial scales, with an example from the Australian vascular flora

Aim  To develop an approach for assessing the spatial scale of centres of endemism among species level data.
Location Australia.
Methods  Endemism is inherently scale dependent. Therefore, the Corrected Weighted Endemism (CWE) index used by Crisp et al. [ J. Biogeogr. (2001)28:183] is extended to account for species samples in local neighbourhoods as a Spatial CWE index. This then allows an analysis of how the degree of endemism of a location (cell) changes with spatial scale. The quality of the Spatial CWE index results are assessed using three spatial randomizations at the species level with and without preserving species richness and distributional patterns. We show that CWE is equivalent to beta diversity and predict that it should show high rates of change around centres of endemism.
Results  Similar patterns to those found by Crisp et al. using a data set of vascular flora from Australia are retrieved, but the extent to which they are scale dependent is more easily identified. For example, the Central Australian centre discounted by Crisp et al. is identified when a three-cell radius neighbourhood is used. However, the level of endemism in this centre is no greater than in the margins of many of the coastal centres of endemism. Most of the identified centres of endemism are better than random at all scales and are increasingly so as the spatial scale increases. As predicted, the highest rate of change in Spatial CWE (beta diversity) is most often between zero- and one-cell radius neighbours in most centres of endemism.
Main conclusions  The explicit incorporation of geographical space in analyses allows for a greater understanding of the scale-dependence of phenomena, in this case endemism and beta diversity.     

Habitat fragmentation and biodiversity: testing for the evolutionary effects of refugia

Concordant areas of endemism among taxa have important implications both for understanding mechanisms of speciation and for framing conservation priorities. Here we discuss the need for careful testing of phylogeographic data for evidence of such concordance, with particular reference to the Indonesian island of Sulawesi. This is because there are good reasons to question whether concordance between taxa is likely to be a common pattern, and because of the serious implications of incorrectly concluding that the biodiversity of a given area can be partitioned in this way.     

Towards biodiversity hotspots effective for conserving mammals with small geographic ranges

The main goal of using global biodiversity hotspots for conservation purposes is to protect taxa with small geographic ranges because these are highly vulnerable to extinction. However, the extent to what different hotspots types are effective for meeting this goal remains controversial because hotspots have been previously defined as either the richest or most threatened and richest sites in terms of total, endemic or threatened species. In this regard, the use of species richness to set conservation priorities is widely discussed because strategies focused on this diversity measure tend to miss many of the taxa with small geographic ranges. Here we use data on global terrestrial mammal distributions to show that, hotspots of total species, endemism and threat defined in terms of species richness are effective in including 27%, 29% and 11% respectively, of the taxa with small geographic ranges. Whilst, the same hotspot types defined in terms of a simple diversity index, which is a function of species richness and range-size rarity, include 68%, 44% and 90% respectively, of these taxa. In addition, we demonstrate that index hotspot types are highly efficient because they conserve 79% of mammal species (21% more species than richness hotspot types), with 59% of species shared by three hotspot types (31% more than richness hotspot types). These results suggest that selection of different diversity measures to define hotspots may strongly affect the achievement of conservation goals.     

Identifying and assessing the efficiency of different networks of a fine-scale hierarchy of biodiversity hotspots

Background: For prioritising practical conservation measures in areas of high endemic plant diversity, a fine-scale hierarchy of sites needs to be established. In this context, conservation sites designed at local and regional levels are considered a network of interconnected areas.

Aims: The main aim was to identify two hierarchical levels of a network of conservation sites, called ‘micro hotspots’ and ‘nano hotspots’, and test their efficiency for achieving conservation objectives across the island of Sardinia, Mediterranean Basin.

Methods: We analysed the spatial distribution of endemic vascular plant species (EVPS) richness. Additionally, the area, perimeter, connectivity and surplus costs for the protection of all endemic plant populations were used as ranking criteria for a hierarchical classification.

Results: We identified eight micro hotspots and 82 nano hotspots. Amongst the three possible solutions compared, the integrated network of micro and nano hotspots resulted in more effective conservation than any of the single-level network solutions with only micro or nano hotspots, and it included 89% of all EVPS in a relatively small areal extent.

Conclusions: The identification of hotspot networks at the regional level allowed determining priority areas to implement conservation efforts for EVPS. The integration of micro hotspots with nano hotspots resulted in the most effective network from both conservation and economic perspectives. We suggest that our model may provide an effective tool for integrated and effective conservation actions in the Mediterranean Basin.     

Macroecological patterns of species and genetic diversity in vascular plants of the Mediterranean basin

Aim We address the question of whether broad scale biogeographical structure of species diversity (SD) matches that of genetic diversity (GD) of vascular plants. Location The Mediterranean basin. Methods We normalized vascular plant species richness (SD) estimates per country using the Med‐Checklist taxonomic database. We used a linear regression analysis to correlate normalized country estimates with country longitudinal position. We also compiled published and geo‐referenced within‐population GD data for tree species, which had populations in the Mediterranean. We normalized GD estimates for each population across species. Again, we used a linear regression analysis to correlate GD with population longitudinal position. We then compared the populations’ geographical and bioclimatic trends for GD with Last Glacial Maximum (LGM) palaeo‐climate data and the species current ecological requirements. Results The eastern Mediterranean and the coast of former Yugoslavia had higher SD than other regions. There was no overall spatial structure of SD in the Mediterranean, whereas there was an east–west trend of decreasing GD. This trend for GD tended to covary with an east–west warm/wet–cold/dry trend detected during the LGM. Low elevation xerothermic pine species displayed significantly less GD than higher elevation mesothermic or mountain pine species. Main conclusions We suggest that LGM climate may have significantly shaped the current longitudinal and altitudinal patterns of GD we observed in woody taxa across the Mediterranean, although it did not affect comparable SD patterns. In particular, colder LGM summer temperatures in the western Mediterranean may have reduced population sizes significantly more than in the eastern Mediterranean. As plant species richness and GD did not covary, SD and GD may not be used as surrogates of one another in the Mediterranean basin. As they contain comparatively less GD, conservation priorities in the Mediterranean should focus on hot spots of endemism and Western Mediterranean populations and species.     

Marine macroalgal biodiversity hotspots: why is there high species richness and endemism in southern Australian marine benthic flora?

The southern Australian marine macroalgal flora has the highest levels of species richness and endemism of any regional macroalgal flora in the world. Analyses of species composition and distributions for the southern Australian flora have identified four different floristic elements, namely the southern Australian endemic element, the widely distributed temperate element, the tropical element and a cold water element. Within the southern Australian endemic element, four species distribution patterns are apparent, thought to largely result from the Jurassic to Oligocene fragmentation of East Gondwana, the subsequent migration of Tethyan ancestors from the west Australian coast and the later invasion of high latitude Pacific species. Climatic deterioration from the late Eocene to the present is thought responsible for the replacement of the previous tropical south coast flora by an endemic temperate flora which has subsequently diversified in response to fluctuating environmental conditions, abundant rocky substrata and substantial habitat heterogeneity. High levels of endemism are attributed to Australia's long isolation and maintained, as is the high species richness, by the lack of recent mass extinction events. The warm water Leeuwin Current has had profound influence in the region since the Eocene, flowing to disperse macroalgal species onto the south coast as well as ameliorating the local environment. It is now evident that the high species richness and endemism we now observe in the southern Australian marine macroalgal flora can be attributed to a complex interaction of biogeographical, ecological and phylogenetic processes over the last 160 million years.     

Ecology and evolution of mammalian biodiversity

Mammals have incredible biological diversity, showing extreme flexibility in eco-morphology, physiology, life history and behaviour across their evolutionary history. Undoubtedly, mammals play an important role in ecosystems by providing essential services such as regulating insect populations, seed dispersal and pollination and act as indicators of general ecosystem health. However, the macroecological and macroevolutionary processes underpinning past and present biodiversity patterns are only beginning to be explored on a global scale. It is also particularly important, in the face of the global extinction crisis, to understand these processes in order to be able to use this knowledge to prevent future biodiversity loss and loss of ecosystem services. Unfortunately, efforts to understand mammalian biodiversity have been hampered by a lack of data. New data compilations on current species' distributions, ecologies and evolutionary histories now allow an integrated approach to understand this biodiversity. We review and synthesize these new studies, exploring the past and present ecology and evolution of mammalian biodiversity, and use these findings to speculate about the mammals of our future.     

Plant biodiversity in the Saint Catherine area of the Sinai peninsula, Egypt

This study focuses on plant species richness, taxonomic diversity, and endemism of the Sinai peninsula as a whole and Saint Catherine area in particular. Beta diversity was also measured using _T to represent the biotic change between different landforms in the St. Catherine area. The peninsula supports about 1285 species including the infraspecific taxa of which about 800 species (also including the infraspecific taxa) are recorded in the southern Sinai south of El-Tih Desert. The present study reveals that southern Sinai is more diverse as compared with the Sinai peninsula as a whole. Southern Sinai also supports more than the expected numbers of rare and very rare species (about 62%) and about 4.3% endemic species. Beta diversity between different landforms in the St. Catherine area reflect a large biotic change between slopes and terraces on the one hand and between terraces and ridges on the other. Finally, the study recommends appropriate management of the peninsula and more research for the management requirements of the numerous endemic and rare species in the Sinai peninsula.     

Water flow drives biodiversity by mediating rarity in marine benthic communities

In aquatic ecosystems, water flow mediates the delivery of reproductive propagules, competition and predation, each of which may have contrasting effects on biodiversity. Here, we show that water flow has a net positive effect on the biodiversity of benthic invertebrate communities in three biogeographic regions. In Palau and Alaska, flow velocity predicted 55-91% of the variance in species richness in natural communities. In experimental communities in Alaska and Maine, enhanced water flow treatments resulted in higher levels of species density (+56%) and richness (+74%), which were predicted by the abundance of locally rare species. Additionally, the richness of recruitment was higher in experimentally enhanced flows (+46%). Thus, the data suggest that flow drives diversity by mediating the delivery of rare species in multiple biogeographic regions. Consequently, flow velocity should be included in future developments of diversity theory and conservation strategy.     

An upgraded national biodiversity risk assessment index

The setting of priorities for international conservation assistance is important due to limited available financial resources. A recent study constructed a national biodiversity risk assessment index (NABRAI) in order to prioritise nations for conservation assistance. The present study aimed to upgrade the original index in order to address computational and weighting inconsistencies. The results of the upgraded index corresponded relatively well with those of the original model. We feel this study goes a step further towards strengthening the methodologies for biodiversity risk assessment. However, due to the absence of theoretical constructs for biodiversity risk assessment and the considerable disagreement between the various models of biodiversity risk, we recognise a need for a more sophisticated understanding of national biodiversity risk before these models can be used to identify global conservation priorities with any degree of confidence.     

Marine nematode deep‐sea biodiversity – hyperdiverse or hype?

Nematodes have been identified as a potentially hyperdiverse group and the deep sea as a potentially hyperdiverse environment (i.e. > 1 million species). A large-scale data set from the equatorial central Pacific is used to estimate regional diversity with results that challenge this view; regional diversity is higher in some coastal waters despite lower sample diversity in coastal waters than in the deep sea. The data suggests a paradigm where the deep sea has modest regional diversity, despite high local diversity through patch dynamics, because similar patches in a similar habitat are repeated for considerable distances. Disturbance in shallow water dominates over patch-dynamic mechanisms reducing local diversity but regional diversity is high because of the close packing of multiple habitats within a single region.
  The Pacific data are also used to demonstrate the pitfalls of extrapolating from local to global diversity. There is no reason to conclude that nematodes are less diverse than other benthic groups, indeed where direct comparison is possible the Nematoda appear to be as diverse as the Polychaeta, the most diverse macrofaunal taxon. This analysis is not consistent with the hypothesis that either marine nematodes or the deep-sea benthos are hyperdiverse raising the question whether any environment or metazoan taxon has more than a million species.     

Understanding investment in biodiversity conservation in Mexico

Documenting financial resources in biodiversity conservation is a key aspect worldwide in order to set priorities and use effectively the limited resources available. In Mexico, a megadiverse country, studies on financial resources invested in biodiversity conservation are scarce and do not address funding for conservation comprehensively. Using recent data from several sources and applying criteria based on the national priorities for conservation, we compiled, systematized and analyzed data at a national scale on financing sources, financial resources and conservation organizations and their projects. The information obtained is presented in various ways and part of it (case study) is already an information system that can be continuously up-dated. Some of the results show the following: a steady diversification of mechanisms and methods for raising funds for conservation; an increase in governmental budgets; the acknowledgment by the private sector of the importance of biodiversity conservation; a greater technical capacity in people and organizations working in conservation; a greater accessibility of financial resources to support and maintain conservation projects; yet a short term vision in conservation projects; among other. Although the results obtained through this study are a first approach, they can now be used as a baseline to continue gathering and analyzing information on conservation financing in Mexico.