High Levels Of Species Richness Research Articles

Diversification rates have declined in the Malagasy herpetofauna

The evolutionary origins of Madagascar's biodiversity remain mysterious despite the fact that relative to land area, there is no other place with consistently high levels of species richness and endemism across a range of taxonomic levels. Most efforts to explain diversification on the island have focused on geographical models of speciation, but recent studies have begun to address the island's accumulation of species through time, although with conflicting results. Prevailing hypotheses for diversification on the island involve either constant diversification rates or scenarios where rates decline through time. Using relative-time-calibrated phylogenies for seven endemic vertebrate clades and a model-fitting framework, I find evidence that diversification rates have declined through time on Madagascar. I show that diversification rates have clearly declined throughout the history of each clade, and models invoking diversity-dependent reductions to diversification rates best explain the diversification histories for each clade. These results are consistent with the ecological theory of adaptive radiation, and, coupled with ancillary observations about ecomorphological and life-history evolution, strongly suggest that adaptive radiation was an important formative process for one of the most species-rich regions on the Earth. These results cast the Malagasy biota in a new light and provide macroevolutionary justification for conservation initiatives.

Sky Islands of the Cameroon Volcanic Line: a diversification hot spot for puddle frogs (Phrynobatrachidae: Phrynobatrachus)

The continental highlands of the Cameroon Volcanic Line (CVL) represent biological ‘sky islands’ with high levels of species richness and endemism, providing the ideal opportunity to understand how orogenesis and historical climate change influenced species diversity and distribution in these isolated African highlands. Relationships of puddle frogs (Phrynobatrachus) endemic to the CVL are reconstructed to examine the patterns and timing of puddle frog diversification. Historical distributions were reconstructed using both elevation and geography data. Puddle frogs diversified in the CVL via several dispersal and vicariance events, with most of the locally endemic species distributed across the northern part of the montane forest area in the Bamenda‐Banso Highlands (Bamboutos Mts., Mt. Lefo, Mt. Mbam, Mt. Oku and medium elevation areas connecting these mountains). Two new species, P. jimzimkusi sp. n. and P. njiomock sp. n., are also described based on molecular analyses and morphological examination. We find that these new species are most closely related to one another and P. steindachneri with the ranges of all three species overlapping at Mt. Oku. Phrynobatrachus jimzimkusi sp. n. is distributed in the southern portion of the continental CVL, P. njiomock sp. n. is endemic to Mt. Oku, and P. steindachneri is present in the northeastern part of the montane forest area. Both new species can be distinguished from all other puddle frogs by a combination of morphological characters, including their large size, ventral coloration and secondary sexual characteristics present in males. These results highlight the Bamenda‐Banso Highlands, and specifically emphasize Mt. Oku, as a centre of diversification for puddle frogs, supporting the conservation importance of this region. Our results also provide new insights into the evolutionary processes shaping the CVL ‘sky islands’, demonstrating that lineage diversification in these montane amphibians is significantly older than expected with most species diverging from their closest relative in the Miocene. Whereas climatic changes during the Pliocene and Pleistocene shaped intraspecific diversification, most speciation events were significantly older and cannot be linked to Africa's aridification in response to Pleistocene climate fluctuations.

Biodiversity conservation in a changing climate: a review of threats and implications for conservation planning in Myanmar.

High levels of species richness and endemism make Myanmar a regional priority for conservation. However, decades of economic and political sanctions have resulted in low conservation investment to effectively tackle threats to biodiversity. Recent sweeping political reforms have placed Myanmar on the fast track to economic development-the expectation is increased economic investments focused on the exploitation of the country's rich, and relatively intact, natural resources. Within a context of weak regulatory capacity and inadequate environmental safeguards, rapid economic development is likely to have far-reaching negative implications for already threatened biodiversity and natural-resource-dependent human communities. Climate change will further exacerbate prevailing threats given Myanmar's high exposure and vulnerability. The aim of this review is to examine the implications of increased economic growth and a changing climate within the larger context of biodiversity conservation in Myanmar. We summarize conservation challenges, assess direct climatological impacts on biodiversity and conclude with recommendations for long-term adaptation approaches for biodiversity conservation.

A high resolution 15,600-year pollen and microcharcoal record from the Cederberg Mountains, South Africa

The Cederberg Mountains (Western Cape Province, South Africa) are located within the Fynbos Biome, which exhibits some of the highest levels of species richness and endemism in the world. The region's post-glacial vegetation history, however, remains largely unknown. Presented here are high resolution pollen and microcharcoal records spanning the last 15,600years obtained from the De Rif rock hyrax midden from the Driehoek Valley of the central Cederberg. In this region, previous pollen studies have shown muted variability in vegetation community composition during periods of globally marked climatic variability (e.g. the last glacial–interglacial transition). In our record, however, significant changes in vegetation composition are apparent. Most notably, they indicate a shift from ericaceous/restioid fynbos (present from 15,600 to 13,300calyr BP) to a brief, but prominent, development of proteoid fynbos at the beginning of the Holocene around 11,200calyr BP. This vegetation shift is associated with increased moisture at the site, and coincides with reduced fire frequency as indicated by the microcharcoal record. At 10,400calyr BP, there is a marked reduction in Protea-type pollen, which is replaced by thicket, characterised by Dodonaea, which became the dominant arboreal pollen type. This shift was likely the result of a long relatively fire-free period coupled with warmer and wetter climates spanning much of the early Holocene. A brief but marked decrease in water availability around 8500–8000calyr BP resulted in the strong decrease of Dodonaea pollen. The vegetation of the mid- to late Holocene is characterised by the increased occurrence of Asteraceae and succulent taxa, suggesting substantially drier conditions. These data give unprecedented insight into the vegetation dynamics across a period of substantial, rapid climate change, and while they confirm the presence of fynbos elements throughout the last 15,600years, the results highlight significant fluctuations in the vegetation that were triggered by changes in both climate and fire regimes.

Determinants of fine-scale plant diversity in dry calcareous grasslands within the Baltic Sea region

We used an extensive dataset (1220 vegetation plots of 1m2) to study vegetation gradients and fine-scale plant diversity in dry calcareous grasslands (including alvar grasslands) in the Baltic Sea region. The study area covers the entire European distributional range of alvar habitats: Sweden (Öland, Gotland, Götaland), Estonia (Saaremaa, Hiiumaa, north Estonia, west Estonia), and western Russia (Izhora, Izborsk). Fine-scale plant diversity was characterized by species richness and standardized phylogenetic diversity (comparing the observed mean pairwise phylogenetic distance (MPD) with MPD values from random communities). Ordination techniques (DCA) were used to characterize the main vegetation gradient. Variables describing local environment, climate, the biogeographic composition of the plant communities, and geographic location were related to fine-scale species richness and phylogenetic diversity using variation partitioning techniques and linear mixed models.The main vegetation gradient in the dry calcareous grasslands in the Baltic Sea region had a strong geographic component, was associated with soil depth, species’ stress- and disturbance-tolerance and the age of the grassland habitat.Fine-scale phylogenetic diversity and species richness were negatively associated suggesting that these two diversity components are influenced by different sets of environmental and historical parameters. Fine-scale species richness was unimodally associated with the main vegetation gradient, and the highest levels of species richness were found under intermediate environmental (disturbance, light conditions and temperature) conditions where there was a mixture of species from different biogeographic regions. In contrast to species richness, fine-scale phylogenetic diversity was negatively associated with the main vegetation gradient. The highest phylogenetic diversity was found in the extremely thin-soiled alvar grasslands in Götaland and on the Baltic islands (especially on Öland) where the high phylogenetic diversity is likely to be a reflection of a long history of continuous openness that has allowed time for the “collection” of phylogenetically different species within these unique habitats.

The Role of Mountain Ranges in the Diversification of Birds

Avian faunas vary greatly among montane areas; those at high latitudes are biologically impoverished, whereas those of some low-latitude mountains are biologically very complex. Their high level of species richness is caused by the aggregation of many small-ranged species, which has been difficult to explain from purely macroecological models focusing on contemporary ecological processes. Because the individual mountain tracts harbor species that represent different evolutionary trajectories, it seems plausible to relate these species assemblages to high persistence (or absence of extinction) in addition to high levels of speciation. The distribution of small-ranged species is concentrated near tropical coasts, where moderation of the climate in topographically complex areas creates cloud forests and stable local conditions. The stability underpins specialization and resilience of local populations, and thereby the role of these places as cradles of biodiversity.

Macrophyte presence and growth form influence macroinvertebrate community structure

Multivariate analysis demonstrated that macroinvertebrate assemblages of macrophyte-dominated sub-habitats within a small eutrophic pond differed markedly from those of Bottom substrate and Open water habitats. Certain habitats (e.g. Nymphaea and Phragmites) appeared to be quite similar in their macroinvertebrate communities, whereas others appeared to be very distinct in terms of the species composition (e.g. Open water habitat). Analysis of functional feeding groups also revealed differences between habitats in terms of the community structure. Again, the Open water habitat exhibiting the most marked difference. Macrophyte growth form does not cause significant differences in macroinvertebrate species richness and diversity but it has a significant effect on macroinvertebrate abundance. Habitats consisting of highly branched and dissected macrophyte growth forms provide more food resources and microhabitats supporting larger numbers of macroinvertebrates than macrophytes with firm undissected stalks and leaves. This study highlights the importance of maintaining the ecological quality of small freshwater habitats in order to promote macrophyte growth and thus maintain a high level of species richness within such ecosystems.

Impacts of Different Land-use Patterns on the Carabid Beetle Diversity and Species Assemblages in South Korea

This work was performed to assess the effect of urbanization on habitat loss. Carabid beetle assemblages were examined from agricultural, forested, and urban areas. Environmental variables, which had the greatest impact on the carabid assemblages, were litter, tree cover, slope, shrub cover, exchangeable calcium, and pH. Eighteen carabid species were collected and identified with respect to the eight land-use types. Natural forest and agricultural habitats both supported higher levels of species richness, relative to urbanized areas. However, both fragmented and managed forests (urban subtypes) also maintained their level of species richness, relative to garden lawns (urban subtype). Comparatively, in rural areas, habitat loss and changes in agricultural practices over time have shown to be more damaging to natural ecosystems than the impact of urbanization on urban landscapes. Alternatively, with a full grasp of the knowledge of the original habitat and the influence of the effects of urbanization on natural landscapes, the biodiversity of urban landscapes can be facultatively improved. More importantly, sustainable management programs such as those aimed at inner city urban agriculture and habitat creation programs are supportive in maintaining ecosystem biodiversity.

Changes In the Vascular Flora of the Middlesex Fells Reservation, Middlesex County, Massachusetts, from 1895 To 2011

Abstract A study of the vascular flora of the Middlesex Fells Reservation, a suburban forest reserve in greater Boston, was made over nine years from 2003 to 2011. We compiled a checklist, determining the frequency of each taxon and documenting all natural community types occurring in the reservation. We compared our findings to those made in the 1890s, and attempted to explain changes in species composition and frequency. Despite many impacts on the reservation in the last century, a high level of species richness was observed, with 868 vascular taxa extant, including 563 native taxa. There was little net change in the number of native taxa found, but a near tripling of non-native taxa from 110 to 305. Habitat destruction, fragmentation, forest succession, fire suppression, trends favoring mesophytic vegetation, climate change, and invasive species are all believed to be factors in the changes observed in the flora.

Rapid altitudinal migration of mountain plants in Taiwan and its implications for high altitude biodiversity

Mountain systems throughout the globe are characterized by high levels of species richness and species endemism. Biodiversity, however, is not distributed evenly with altitude, but often declines from mid to high altitudes. Conversely, endemic species may be over‐represented at high altitudes. Upward elevational range shifts of mountain species have been reported in response to ongoing changes in climate, yet the reports are dominated by studies on woody species and mountains at high latitudes. We investigated spatial and temporal changes in the mountain biodiversity in the subtropical island of Taiwan, based on historical survey and resurvey data during the period 1906–2006. We found that upper altitudinal limits of mountain plant distributions have risen by ca 3.6 m yr−1 during the last century, in parallel with rising temperatures in the region. Although species, genus, and family richness decline with altitude, ca 55% of species at the highest altitudes are endemic to the island. Given the steep decline in land area with increasing elevation, these high altitude areas are disproportionately important for plant biodiversity when richness and endemism are standardized by available land area. We argue that the distributional shift that we report, in combination with the altitudinal distribution of plant diversity, is likely to pose a major threat to high mountain species of this highly biodiverse island, a threat that is becoming increasingly evident for high mountain plants throughout the globe.

Structure of epiphyton communities on Lake Baikal submerged macrophytes

Abstract We carried out a first study of Lake Baikal epiphyton on six species of submerged macrophytes: Myriophyllum spicatum L., Potamogeton perfoliatus L., Potamogeton sp., Sparganium gramineum Georgi, Ceratophyllum demersum L., and Elodea сanadensis Michaux. We identified 70 epiphyton species and intraspecific taxa belonging to 3 phyla, viz. Ochrophyta, Cyanobacteria, and Chlorophyta. Nine species of Cyanobacteria were new records for Lake Baikal. Epiphyton communities differing in species composition and quantitative characteristics grew on diverse species of submerged macrophytes. High levels of species richness were recorded on Sparganiumgramineum and Potamogeton sp., whereas low diversity of epiphyton was observed on Myriophyllum spicatum and Elodea canadensis. A monodominant community was revealed on the invasive Elodea canadensis represented by Cocconeis placentula var. placentula. Specific characteristics of morphology of submerged macrophytes influenced the structural organization and quantitative development of epiphyton. Epiphyton abundance and biomass were higher on upper sections of most plants than on lower sections, probably because of canopy shading of macrophyte lower portions.

Study of Mammal Diversity in Xuan Nha and Muong Do Nature Reserves, Son La Province, Northwestern Vietnam

The southern part of China and northern part of Indochina Peninsula are a ‘hot-spot’ of biodiversity (e.g., Cincotta et al. 2000; Cox and Moore 2005). This area also shows striking endemism of mammalian species; for instance, the giant panda Ailuropoda melanoleuca, saola Pseudoryx nghetinhensis, and Tonkin snub-nosed monkey Rhinopithecus avunculus are confined in this area (e.g., Wilson and Reeder 2005). Investigation of this area’s mammal fauna could have be insightful to the evolutionary history of mammals. Son La Province is located in this area, about 200 km west of Hanoi, Vietnam, at coordinates 20°39'–22°02'N, 103°11'–105°02'E. The province has total area of 14,055 km 2 , sharing about 250 km international border with Laos, and is characterized by very complex mountainous terrain, and tropical humid forest cover. The tropical forests contain high biodiversity values of national and international significance (Baltzer et al. 2001; MoNRE 2005; Tordoff et al. 2007). During recent decades, however, these biodiversity values have been seriously threatened and degraded due to increasing human population and rapid economic development. In situ conservation effort are necessary to halt biodiversity decline (Balmford et al. 1996; Sarat and Kalemani 2004); five nature reserves (NR) have been established or proposed by Son La Province to conserve its biodiversity values. Baseline biodiversity assessments of these NRs is required to develop strategies for effective NR management. In Son La Province, there are many mountains; different altitudes produce different distribution patterns of mammalian species (e.g., Chappel 1978). The wide altitudinal range, with variable topographic features, in Son La may promote different distribution patterns of mammalian species and high levels of species richness. To investigate this supposition in this area, we compared preliminary data on mammalian species richness between two NRs (Xuan Nha NR and Muong Do NR), which differ in elevation. As there are many species in biodiversity hotspot, this area could be suitable to examine differences of species diversity of mammals. The elevation of Xuan Nha NR ranges from 300 to ca. 2,000 m a.s.l., while that of Muong Do NR is lower (300 to ca. 1,000 m). We expect that number of mammalian species in Xuan Nha NR could be significantly more than that in Muong Do NR. We preliminary discuss the relationship between species richness and altitude on the Indochina Peninsula. This paper also presents an updated list of mammal species recorded in the NRs and evaluates their conservation importance. This study is the first mammal investigation in Muong Do NR, except bat surveys by Vu et al. (2009).

Sampling period, size and duration influence measures of bat species richness from acoustic surveys

Summary1. Understanding animal ecology depends on an ability to accurately inventory species. However, there are few quantitative data available, which allow for an assessment of the effectiveness of acoustic sampling methods for determining bat species richness.2. We assessed inventory efficiency, defined as the percentage of species detected per survey effort, using data from 7 to 9 Anabat bat detectors deployed concurrently between June 2008 and August 2009 at fixed locations. We examined sampling period and time of night to calculate the minimum duration of sampling effort required to detect the greatest percentage of species.3. In all cases, multiple survey nights at multiple sampling locations were necessary to detect higher levels of species richness using acoustic detectors. Additionally, continuous sampling throughout the night was important for detecting more species, especially during summer, fall and spring months.4. Species accumulation curves indicated that relatively few nights were needed to detect ‘common’ species at various sampling locations (2–5 nights on average); however, longer sample periods (>45 nights) were necessary to detect ‘rare’ species at some sampling locations. Accumulation curves indicated that the number of detector locations positively influenced the number of species detected during surveys periods.5. A priori knowledge of sampling effort is fundamental for designing biologically robust inventories. We make recommendations for improving the efficiency of acoustic surveys using analytical methods that are broadly applicable to a range of survey methods and taxa.

DIVERSIFICATION AND BIOGEOGRAPHIC PATTERNS IN FOUR ISLAND RADIATIONS OF PASSERINE BIRDS

Declining diversification rates over time are a well-established evolutionary pattern, often interpreted as indicating initial rapid radiation with filling of ecological niche space. Here, we test the hypothesis that island radiations may show constant net diversification rates over time, due to continued expansion into new niche space in highly dispersive taxa. We investigate diversification patterns of four passerine bird families originating from the Indo-Pacific archipelagos, and link these to biogeographic patterns to provide independent indications of niche filling. We find a declining diversification rate for only one family, the Paradisaeidae (41 species). These are almost completely restricted to New Guinea, and have on average smaller species ranges and higher levels of species richness within grid cells than the other three families. In contrast, we cannot reject constant diversification rates for Campephagidae (93 species), Oriolidae (35 species), and Pachycephalidae (53 species), groups that have independently colonized neighboring archipelagos and continents. We propose that Paradisaeidae have reached the diversity limit imposed by their restricted distribution, whereas high dispersal and colonization success across the geologically dynamic Indo-Pacific archipelagos may have sustained high speciation rates for the other three families. Alternatively, increasing extinction rates may have obscured declining speciation rates in those three phylogenies.

Topographic and biotic regulation of aboveground carbon storage in subtropical broad-leaved forests of Taiwan

There is a growing need to understand, and ultimately manage, carbon storage by forest ecosystems. Broad-leaved evergreen forests of Taiwan provide an outstanding opportunity to examine factors that regulate ecosystem carbon storage. We utilized data from three Taiwan Forest Dynamics Plots (FS, LHC, and PTY) in which every tree is identified, measured, tagged and mapped, to examine factors regulating carbon storage as estimated from aboveground biomass. Allometric equations were used to estimate the aboveground biomass of each tree, and a model building procedure was used to examine relationships between plot-level aboveground biomass (AGB; Mg/ha) and a suite of topographic and biotic factors. We found that our study sites have AGB values comparable to some of the most carbon dense forests in the world. Across all three sites, maximum biomass was contained in the taxonomic families Fagaceae, Lauraceae and Theaceae. In the FS site, we identified slope convexity ( P = 0.03) and elevation ( P < 0.001) as topographic predictors of AGB and found that maximum AGB was found in topographically flat areas. In FS, stem density ( P < 0.001) was a significant biotic predictor of AGB and the maxima occurred at intermediate densities. In LHC, we found that convexity ( P < 0.001) and slope ( P < 0.001) were significantly related to AGB which was maximized along a topographic ridge in the plot. Species richness ( P < 0.001) was a significant biotic predictor of AGB in LHC, and the relationship indicated slightly higher AGB at higher levels of species richness. The only significant factor related to AGB in PTY was species richness ( P = 0.02). Further work is needed to seek a mechanistic understanding of topographic factors and species richness as drivers of carbon storage in forests.

Genetic structure and variability of the endemic and vulnerable Vellozia gigantea (Velloziaceae) associated with the landscape in the Espinhaço Range, in southeastern Brazil: implications for conservation

The Espinhaço Range, in eastern Brazil, has a peculiar landscape that has influenced the vegetation pattern of the region because of its valleys, canyons, ranges and disjunct rock outcrops found at high elevations. In this region, the vegetation type known as campos rupestres (rupestrian fields), which occurs in the disjunct outcrops, has high levels of species richness and endemism. Vellozia gigantea, a 6-m tall dracenoid monocot, is a vulnerable species endemic to this vegetation and has a narrow distribution that extends approximately 27 km. This region is located in a disturbed area, where populations are divided into three geographical groups, separated by a canyon and a valley. For this study, we used ISSR markers to measure the genetic diversity of the species and test the hypothesis that the canyon and the valley constitute geographical barriers to gene flow in V. gigantea. Nine populations and 173 individuals were analyzed using nine ISSR primers, which produced 89 fragments. In spite of being a vulnerable species with a narrow distribution, the populations of V. gigantea have high genetic diversity (mean percentage of polymorphic loci = 56.6%; mean Shannon's index of diversity = 0.278; mean expected heterozygosity = 0.183). Genetic divergence among populations was high (Φ(ST) = 0.28), and principal coordinate, neighborjoining and Bayesian analyses showed that only the canyon may constitute a partial barrier to gene flow in this species. Groups of populations separated by the canyon should be managed separately because they contain different gene pools.

Biogeographic patterns of spiders in coastal dunes along a gradient of mediterraneity

The Iberian Peninsula is recognized for its high levels of species richness, rarity and endemicity. Our main aim was to study biogeographic patterns of spiders in coastal dunes along a gradient of mediterraneity. Distance-decay of similarity, nestedness and co-occurrence metrics were used to explore spider’ distribution patterns. A similarity analysis was performed in order to obtain a hierarchical classification of sites. Indicator species analysis was conducted to identify indicator species for the various clustering levels of the site typology. The differentiation among assemblages was further explored by non-metric multidimensional scaling (NMDS) and analysis of similarities (ANOSIM). Assemblages’ similarity among sites decreased with climatic/geographic distance. The observed values of nestedness metrics (T and NODF) were not significant, while the co-occurrence metrics (C-score and Checkerboard units) were higher than expected by chance. Cluster analysis showed that spider’ assemblages were structured along a gradient from North to South, forming four geographically distinct clusters. ANOSIM tests and NMDS supported the biogeographic patterns identified by cluster analysis. Several indicator species were found for the different levels of the hierarchic site typology. Spider assemblages revealed a high degree of biogeographical structure along the Atlantic coast of the Iberian Peninsula. The coast is a “biogeographic crossroad”, encompassing faunistic elements of different origins. The hierarchic typology of sites is generally consistent with the major biogeographic regions and the thermoclimatic belts recognized for the region. Our results indicate that the climatic gradient and historic factors played a key role in the current spiders’ biogeographic patterns.

Determinants of beta diversity of spiders in coastal dunes along a gradient of mediterraneity

AbstractAim The Mediterranean Basin is recognized for its high levels of species richness, rarity and endemicity. Our main aim was to evaluate the relative effects of environmental and spatial variables and their scale‐specific importance on beta diversity patterns along a gradient of mediterraneity, using spiders as a model group.Location This study was carried out in 18 coastal dune sites along the Portuguese Atlantic coast. This area encompasses 445 km and comprises two distinct biogeographic regions, Eurosiberian (northern coast) and Mediterranean (centre and south).Methods A forward selection procedure was carried out to select environmental and spatial variables responsible for determining beta diversity patterns. Variation partitioning and principal coordinates of neighbour matrices (PCNM) were used to estimate the contribution of pure environmental and pure spatial effects and their shared influence on beta diversity patterns and to estimate the relative importance of environmental structured variation and pure spatial variation at multiple spatial scales.Results Climate, ground vegetation dune cover and area were selected by a forward selection procedure. The same procedure identified three PCNM variables, all corresponding to large and medium spatial scales. Variation partitioning revealed that 46.1% of the variation of beta diversity patterns was explained by a combination of environmental and PCNM variables. Most of this variation (42.5%) corresponded to spatial variation (environmental spatially structured and pure spatial). Climate and vegetation structure influences were predominant at the PCNM1 and PCNM3 scales, while area was more important at the intermediate PCNM2 scale.Main conclusions Our study revealed that beta diversity of spiders was primarily controlled by a broad‐scale gradient of mediterraneity. The relative importance of environmental variables on the spider assemblage composition varied with spatial scale. This study highlights the need of considering the scale‐specific influence of niche and neutral processes on beta diversity patterns.

Heterogeneidade do habitat, riqueza e estrutura da assembléia de besouros rola-bostas (Scarabaeidae: Scarabaeinae) em áreas de cerrado na Chapada dos Parecis, MT

Ecological theory of habitat heterogeneity and limited niche-similarity assumes that more heterogeneous environments provide a greater amount and diversity of resources than simple environments, resulting in a greater diversity of species. This study aimed to evaluate the effect of the habitat heterogeneity on the richness of dung beetles and to examine the spatial patterns of assemblage structure in relation to patterns of habitat heterogeneity. Dung beetles were collected using pitfall traps without bait in 30 points distributed in an area of cerrado sensu lato, in the region of Tangará da Serra, MT, Brazil, including areas of cerrado sensu stricto, campo sujo, cerradão and gallery forest. A total of 1,291 dung beetles were collected, distributed in 16 genera and 29 species. Overall habitat heterogeneity exerted a negative effect on patterns of dung beetles richness. Higher levels of species richness were observed in areas of cerrado campo sujo, while the areas of gallery forest were the most species poor. Regarding assembly structure, it was found that the dung beetles were separated into two major groups, one formed by the presence of specialized species in forest areas and other composed of species that occurred predominantly in cerrado. In conclusion, it was found that habitat complexity influenced the distribution of dung beetles, but the level of turnover in species composition along the heterogeneity gradient was relatively weak.

Biofilm: A crucial factor affecting the settlement of seaweed on intertidal rocky surfaces

We hypothesized that the presence of biofilm accelerated the settlement of dominant seaweed species and maintained high levels of species richness by regulating the blooming of particular species on an intertidal rocky shore. The coverage and species richness of macroalgae on sterile and cleared substrates (225 cm 2) were measured to investigate the effects of biofilm on the settlement of macroalgae in intertidal zones at Noryang, Songmoon, and Sangnam in Gawngyang Bay on the southern coast of the Korean peninsula. Green algae coverage on cleared substrates was significantly higher than that on sterile substrates at both Noryang and Songmoon during the study period. This suggests that the presence of biofilm enhances the settlement of green algae by providing various habitat structures and, consequently, may lead to serious ‘green tide’ events. However, the coverage of algae other than green algae and algal species richness on cleared substrates remained high at Sangnam during the experimental period. Biofilm facilitated the settlement of macroalgae and inhibited the blooming of specific algae by inducing inter-specific space competition. Therefore, biofilm plays an important role on seaweed assemblages on intertidal rocky shores by accelerating the settlement of seaweed.