Alarming evidence of widespread mite extinctions in the shadows of plant, insect and vertebrate extinctions

This paper studied the species diversity and fauna distribution of chigger mites on small mammals in Yunnan province, southwest Yunnan. In total, 120,138 individuals of chigger mites were collected from 13,760 individual small mammals, and these mites were identified as comprising two families, 26 genera, and 274 species. Of the five zoogeographical subregions, the mite species diversity in subregions I and II was higher than that in subregions III, IV, and V. Four mite species (Leptotrombidium scutellare, Leptotrombidium sinicum, Leptotrombidium deliense, and Helenicula simena) were the most dominant species in the whole province. Several vector species of chigger mites co-existed in Yunnan, and L. deliense (a main vector of scrub typhus in China) was mainly distributed in subregions IV and V with lower latitude and average altitude whereas L. scutellare (also a main vector in China) was mainly distributed in subregions I, II, and III with higher latitude and average altitude. Some geographically widely distributed mite species were also the mites with wide host ranges and low host specificity. The dominant mite species and their clustering tendency in the dendrogram of hierarchical clustering analysis were highly in accordance with the zoogeographical divisions. The species diversity of chigger mites showed a parabolic tendency from the low altitude (<500 m) to the high altitude (>3,500 m) along the vertical gradients and reached the highest value in the middle altitude regions in 2,000-2,500 m. The highest species diversity of the mites and their small mammal hosts happened in the regions around the Hengduan Mountains, which is a hotspot of biodiversity in Asia continent. The host and its sample size, geographical scope, landscape, topography, and some other factors comprehensively influence the species diversity and faunal distribution of chigger mites. A systematic field investigation with a wide geographical scope and large host sample is strongly recommended in the fauna study of chigger mites and other ectoparasites.

Tropical rain forests as carbon sinks

The rich biodiversity repository of Gandhamardan hill ranges, Eastern Ghats, India is under severe threat from various magnitudes such as deforestation, unsustainable collection of medicinal plants, invasion of alien species, forest fire, urbanization and habitat destruction. The Protected Forests (PFs) have lost a number of wild species from their natural habitat pose to loss of biodiversity. The hill range having two preservation plots of 100ha each identified in Nrusinghanath (SITE-I) and Harishankar (SITE-Ⅱ) range as study area. The present study inventoried a total of 10775 trees belonging to 91 tree species within a 17.6 hectare sampled area (441 plots). The predominant tree species are Diospyros melanoxylon, Madhuca indica, Cleistanthus collinus, Anogeissus latifolia, and Lagerstroemia parviflora. The Shannon-Weiner index (H') is 3.92 (SITE-Ⅰ) and 3.31 (SITE-Ⅱ) with Simpson's value 1.0. This value indicates that the tropical moist deciduous forests are also species diverse systems. Mean stand density was 671 ha^(-1) in SITE^(-1) and 565 ha^(-1) in SITE-II. Stem density and species richness have consistently decreased with increasing girth class of tree species from 50 cm girth. The present study on phyto-diversity of tree species and participatory approaches on sustainable use of natural resources will provide the baseline information for effective and sustainable biodiversity conservation of tropical moist deciduous forest.

The rich global biodiversity is threatened with erosion on an unprecedented scale. While the rates of extinction were roughly equal to those of speciation for most of the history of life on earth, contemporary extinction rates are several times faster than those of speciation leading to erosion of Biodiversity (UNEP, 1995). Wemay already be losing 50 to 100 species per day (Myers, 1986). Conservation biologists caution that 25 percent of all species could become extinct during the next 20 to 30 years. During the last 200 million years about 100 species became extinct in each century due to natural evolutionary processes. At the same time evolution ushered in new life forms that more than compensated the species lost. Today the extinction rate is approximately 40,000 times higher than this background rate due to the depredations of Homo sapiens. The Holocene extinction rates of decline in biodiversity in this sixth mass extinction match or exceed rates of loss in the five previous mass extinction events in the fossil record. Previous mass extinctions had no palpable effect on terrestrial plants; but today for the first time an enormous proportion of terrestrial plant species which form the basis of land ecosystems are threatened (Knoll, 1984). A disappearing plant can take with it 10 to 30 dependent species such as insects, higher animals and even other plants. In 2006 many species were formally classified as rare or endangered or threatened. Moreover, scientists have estimated that several species are at risk which have not been formally recognized. About 40 percent of the 40,177 species assessed using the IUCN Red List criteria are now listed as threatened with extinction. There is a growing concern on the prospect of accelerating loss of species, populations, domesticated varieties and natural habitats such as tropical rainforests and wetlands. Recent estimates suggest that more than half the habitable surface of the planet has been significantly altered by human activity. World Conservation and Monitoring Centre (WCMC, 1992) has estimated the number of species of plants and animals extinct since 1600 as 654 and 484 respectively. One of the estimates suggests that tropical forests are being denudedat the rate of 15.4million ha per annum or approximately 1.8% of the remaining forest cover. This will undoubtedly cause the loss of innumerable species and populations of plants and animals and thus will impoverish the global species and genetic diversity. Despite their high diversity, tropical forests are fragile ecosystems and are less capable to recover from repeated human depredations than temperate forests. Tropical humid forests in general are amongst themost diverse, most productive andmost threatened of the biological communities with indeed 14 of the 18 biodiversity hotspots identified by Myers representing these biomes. Two of these hot spots viz., the Eastern Himalayas and the Western Ghats occur in India. But both these hot spots are threatened. To quote Dr. M. S. Swaminathan, both are paradises of valuable genes but are fast inching towards the status of “Paradise Lost.’’ At least 10 percent of India’s recorded wild flora and possibly more of its wild fauna are on the list of threatened species many of which are on the brink of obliteration. Of the wild fauna 80 species of mammals, 47 of birds 15 of reptiles, 3 of amphibians and a large number of moths, butterflies and beetles are listed as endangered. Out of 19 species of primates, 12 are endangered. The cheetah (Acinonyx jubatus) and the pink headed duck (Rhodonessa caryophyllacea) are among the well known conspicuous species that have become extinct; but there must be many more that have been totally annihilated unrecorded either because they were not that spectacular or because we simply were not aware of their existence (Balaji, 2010). Despite the discrepancy in the different estimates (Table 5.1) all prognoses lead tothe conclusion that what is taking place is not just loss of individuals but biodiversity as a whole is endangered.

Loss of tropical forests is the greatest threat to insect diversity globally, as tropical forests harbour the majority of all insect species and the destruction of tropical forests continues at the high annual rate of 0.5–1% (FAO 2001; Pimm 2001; Hanski 2005). The current estimate of globally extinct or threatened species of insects, a mere 0.07% of all insect species (IUCN 2004), does not imply a great threat to insects, but almost certainly this figure reflects more lack of knowledge rather than lack of real threat. A recent analysis of the past and current occurrences of Helictopleurini (Scarabaeidae) dung beetles in Madagascar suggested that forest loss has caused the apparent extinction of nearly half of the described species (Hanski et al. 2007). This result is strikingly consistent with the prediction stemming from the species-area relationship, as only about 10% of the original forest cover remains in Madagascar. Habitat loss is equally high or even higher in many other biomes. Mediterranean forests, woodlands and scrub, temperate steppe and woodland, and temperate broadleaf and mixed forests had lost more than 50% of their potential area before 1950 (MA 2005). The additional projected loss from 1990 to 2050 is greater than 10% of the potential area for tropical and sub-tropical moist broadleaf forests, for tropical and sub-tropical dry broadleaf forests, tropical and sub-tropical grasslands, savannas and shrublands, tropical and sub-tropical coniferous forests, as well as for montane grasslands and shrublands (MA 2005). At the regional scale, the area lost already exceeds 80% for 10s of the world’s 810 ecoregions, and is close to 100% for some of them (Hoekstra et al. 2005). In striking contrast, both the past and projected conversion of boreal forests is minimal, a few percent of their potential area (MA 2005). This may appear to cause little concern about biodiversity of insects and other taxa in boreal forests, but unfortunately such a conclusion is unwarranted. In the global assessments of habitat loss (MA 2005), no distinction is made between natural and managed forests. Extraction of timber and other forest products is compatible with maintenance of biodiversity if the intensity of resource use is not very high and if forest cover is mostly maintained. For instance, slash-and-burn agriculture as practiced in boreal forests in northern Europe in the 17 and 18th century affected large areas, but not the entire forested landscape, because of relatively low human population density and because much of the land is unsuitable even for this form of cultivation, and hence the overall and large-scale impact on insect diversity was probably minor. In northern Europe, and increasingly in other boreal parts of the world, the situation has changed dramatically in the past decades with forestry becoming highly industrialised. I take as an example Finland, which I know best and where industrial forestry is probably more advanced than anywhere else in the boreal forest region in the world. Nonetheless, similar considerations apply to elsewhere in northern Europe and parts of North America. Forestry has become so advanced technologically and in terms of the infrastructure that the ever-diminishing work force can manage the entire area of 20 million ha of forested land in Finland, practically down to the level of single big trees. With around 140,000 km of forest roads, or on average 0.7 km for every square km of forested land, practically the entire forested land is within the reach of I. Hanski (&) Department of Biological and Environmental Sciences, University of Helsinki, P.O. Box 65, Helsinki FI-00014, Finland e-mail: ilkka.hanski@helsinki.fi

Introduction

The relationship between the pine bark beetle Ips sexdentatus and its phoretic mites in a Pinus pinaster forest in northwest Spain was studied during 2014. Four species of mites were collected, three of them from the body of the beetle-Histiostoma ovalis, Dendrolaelaps quadrisetus and Trichouropoda polytricha-the fourth, Cercoleipus coelonotus, was collected from the sediments. The main aims of this study were to explore (1) mite diversity and related parameters, (2) the location on the body of the (male and female) beetle, as well as mite assemblages, and (3) the seasonal dynamic association between mite species and the beetle. Results indicated that the diversity oscillated around 0.71 through the study period and the most dominant, frequent and abundant mite was H. ovalis. Histiostoma ovalis was found attached to almost all parts of the body (mainly on the elytral declivity and ventral thorax), whereas D. quadrisetus was exclusively found under the elytra, and T. polytricha displayed affinity towards the elytral declivity as well as the ventral thorax. None of the mite species displayed any preference for the sex of the beetle and the most frequent mite assemblage was H. ovalis, T. polytricha and D. quadrisetus all together. Maximum abundance of each phoretic mite species was related with each of the flight peaks of the beetle that would indicate that these mite species use phoresy as a primary method of transport for colonizing new food sources.

The tropical wet evergreen, tropical semi evergreen and moist deciduous forest types are projected to be impacted by climate change. In the Western Ghats region, a biodiversity hotspot, evergreen forests including semi evergreen account for 30% of the forest area and according to climate change impact model projections, nearly a third of these forest types are likely to undergo vegetation type change. Similarly, tropical moist deciduous forests which account for about 28% of the forest area are likely to experience change in about 20% of the area. Thus climate change could adversely impact forest biodiversity and product flow to the forest dependent households and communities in Uttara Kannada district of the Western Ghats. This study analyses the distribution of non-timber forest product yielding tree species through a network of twelve 1-ha permanent plots established in the district. Further, the extent of dependence of communities on forests is ascertained through questionnaire surveys. On an average 21% and 28% of the tree species in evergreen and deciduous forest types, respectively are, non-timber forest product yielding tree species, indicating potential high levels of supply of products to communities. Community dependence on non-timber forest products is significant, and it contributes to Rs. 1199 and Rs. 3561/household in the evergreen and deciduous zones, respectively. Given that the bulk of the forest grids in Uttara Kannada district are projected to undergo change, bulk of the species which provide multiple forest products are projected to experience die back and even mortality. Incorporation of climate change projections and impacts in forest planning and management is necessary to enable forest ecosystems to enhance resilience.Key Words: climate change, non-timber forest products, yield, tropical forests, Western Ghats

Tropical rain forests are disappearing rapidly as a result of increasing human encroachment. During the past century, tropical rain forests have been reduced to about half of their original area. And the rate of deforestation is accelerating, fueled by population growth in developing countries and resource demands in the developed countries. The remaining forests are subject to increasingly intensive human use. Deforestation, fragmentation, and exploitation cause a plethora of problems, including soil erosion; siltation of rivers, lakes, and estuaries; increased flooding and droughts; release of carbon dioxide and other greenhouse gases into the atmosphere; and loss of species. In recent years, these problems have become the subject of international concern. This book focuses on the loss of biodiversity in tropical rain forests and on the role of protected areas in stemming the loss. This chapter examines the meaning of biodiversity and the history of the park movement in the tropics. What began as protection of habitat through the exclusion of people has transformed into sustainable use of biological resources. This new emphasis provides local control of important resources and greater income, but does it conserve habitat and species? We will argue that a renewed focus on protected areas as the primary storehouse of biodiversity is needed. We will also make the case for a focus on the tropical rain forest biome and will conclude with an overview of the rest of the book. In its strict sense, biodiversity refers to the “variety and variability among living organisms and the ecological complexes in which they occur” (Office of Technology Assessment, U.S. Congress, 1987:3). This definition can be extended both downward to cover genetic variability within a species and upward to include habitat and ecosystem diversity. practical terms, however, biodiversity is most profitably expressed as species diversity (weighted for rarity, endemism, and taxonomic distinctiveness, if necessary) at the landscape level (see chapter 6). We adopt this definition of biodiversity. During the past few years, attempts to link rain forest protection with sustainable development have led to a noticeable expansion of the meaning of the phrase “biodiversity conservation.”

Floristic structure and biomass distribution of a tropical seasonal rain forest in Xishuangbanna, southwest China

ABSTRACTAimThe Indo‐Australian Archipelago is known as a biodiversity hotspot with high levels of endemism typically ascribed to vicariance as reflected by the ‘Wallace's line’. However, it is unknown how vicariance has affected belowground biodiversity, especially process‐based beta diversity. Here, we relate beta diversity of soil oribatid mite (Oribatida, Acari) assemblages to geographic distance as well as climatic and soil factors to explore the factors shaping the diversity of oribatid mites across 11 regions of the Indo‐Australian Archipelago.LocationIndo‐Australian Archipelago.Time PeriodPresent.Major Taxa StudiedOribatida, Acari.MethodsWe compiled a list of 2549 oribatid mite species in the Indo‐Australian Archipelago and investigated the level of endemism and beta diversity of oribatid mites in the 11 regions at species, genus and family level. We then summarised the biogeographical dissimilarity patterns of oribatid mites using ordination and clustering methods and compared the patterns with the zoological boundaries based on aboveground taxa such as Wallace's, Lydekker's, Weber's and Holt's lines. We integrated data on geography, climate and soil to reveal the key drivers of species compositional dissimilarity of oribatid mites among regions using Mantel tests.ResultsGenerally, the level of endemism of oribatid mite assemblages in the 11 regions was high; they formed three groups (west of New Guinea, New Guinea and south of New Guinea) with dissimilarity changing from northwest to southeast. The patterns reflect and integrate the lines of Weber, Lydekker and Holt. Species turnover generally correlated with geographic distance, reflecting the critical role of vicariance in dispersal‐limited oribatid mites.Main ConclusionsOur results, for the first time, demonstrate contrasting patterns in below‐ and aboveground organisms in the Indo‐Australian Archipelago, and elucidate how geographic distance‐based vicariance has structured soil animal diversity in this biodiversity hotspot region.

Biodiversity Conservation Targets: How to Allocate Resources

How can we save forest biodiversity?

To investigate the storage relationships between and production of organic matter in tropical forests and climate, data on forest biomass, soil organic matter, litter storage, primary production, and litterfall were surveyed from the literature and organized using the Holdridge Life Zone system of classification. Ordinary least squares regressions were applied to all the data sets using the ratio of temperature to precipitation (T/P) as an index to climate and the independent variable. Total forest biomass (40-538 t/ha) gave a significant inverted U-shaped relationship with T/P, with peak values in the tropical moist forest life zone and lower ones in wetter and drier forest life zones. Soil carbon content (24-599 t C/ ha) decreased exponentially and significantly with increasing T/P (i.e., from wet to dry forest life zones). No significant relationship was found between litter storage and T/P. Gross primary production (19-120 t/ha yr) decreased curvilinearly and significantly with increasing T/P. Neither net primary production (11-21 t/ha yr) nor wood production (1-11 t/ha yr) were related to T/P. The ratio of leaf litter production to net primary production (0.25-0.65) was inversely related to T/P, suggesting different strategies of allocation of the net primary production in different life zones. The relationship between total litterfall (1.0-15.3 t/ha yr, excluding large wood) and T/P was significant and its shape similar to that obtained for biomass versus T/P; litterfall was highest in tropical moist forest life zones and lower in wetter or drier ones. The linear relationship between biomass and litterfall suggested that the turnover time of biomass in mature tropical forests is similar for all life zones, and is of the order of 34 yr. To determine the role of tropical forests in the global carbon cycle, literature estimates of areas of tropical forests were placed into six life zone groupings. The total tropical and subtropical basal and altitudinal forest area of 1838 million ha was comprised of 42 percent dry forest, 33 percent moist forest, and 25 percent wet and rain forest life zone groups. Organic-matter storage data were also combined into the six life zone groups and the means for each group calculated. The product of forest areas in the six groups and the mean organic matter per unit area in the groups yielded a total storage of 787 billion t organic matter, with vegetation accounting for 58, soils 41, and litter 1 percent. About half of the total storage was located in the tropical basal wet, moist, and dry forest life zone groups. Litterfall data were treated in the same way as organic-matter storage, resulting in a total litter production in tropical forests of 12.3 billion t organic matter/yr. Most litter was produced in the tropical basal moist forest group (30%) and least in the tropical basal dry forest group (10%). Turnover time of litter in tropical forests was less than 1 yr. Lowest turnover times were in very wet (1 yr) and in dry (0.9-1.9 yr) life zone groups. Tropical forests play an important role in the global carbon cycle because they store 46 percent of the world's living terrestrial carbon pool and 11 percent of the world's soil carbon pool.

Extinction in the Anthropocene.