Diversity, distribution and conservation of tribe Bignonieae (Bignoniaceae) in Northern and Northwestern Paraná, Southern Brazil

Assessing the representativeness of protected areas is necessary to optimize their national and regional networks, as well as to improve the protection of rare and endemic species. In the Republic of Bashkortostan, an analysis of the distribution of rare vascular plant species in need of protection has been carried out on the basis of synthesizing all sources of high-precision georeferenced data, i.e., databases of herbarium specimens and geobotanical releves. The result of these works was the creation of a graphic database: the Rare and Endangered Species of Vascular Plants of the Republic of Bashkortostan GIS map. This GIS map includes three main vector layers: a point layer containing information about 4932 rare species localities, a Protected Areas Boundaries layer, and a grid layer with cells 6' in latitude by 10' in longitude (10.8 × 10.2 km). Based on these layers and standard procedures of the QGIS 3.4 program, an algorithm has been developed to analyze the patterns of distribution of rare species throughout the region, as well as to identify areas with a high diversity of these species and their covering by the existing network of protected areas. Using the example of two grid map cells with a high diversity of rare species, approaches to identifying and delineating further sites of protected areas have been considered using space images and a digital elevation model. To estimate the protection level of the unique combinations of rare species, the distribution of all sets of these species within the existing protected areas is assessed. This makes it possible to justify the creation of two new protected areas. This approach does not exclude, but significantly reduces the volume of field investigations and can significantly reduce the time and financial costs of creating new protected areas to optimize the protection of rare and endangered plant species.

One of central problems in ecology is to explain species diversity in communities, and a considerable number of hypotheses with this purpose have been formulated during last three decades. One very influential group of hypotheses, largely emanating from Hutchinson (1959, 1961), seek explanations in terms of mechanisms of coexistence. The question addressed by these hypotheses is: why are there so many coexisting species? (implicitly assuming that most potential inhabitants of a certain community are present, or have at least had opportunity to be present, but may have been subsequently outcompeted). These hypotheses usually predict that species, in order to coexist, in some way must avoid negative effects of competition. A common theme for wide array of mechanisms suggested to have this, or alike, effects (e.g. Hutchinson 1961, MacArthur 1972, Grubb 1977, Grime 1979, Huston 1979, Tilman 1982, Fagerstrom 1988) is that they are confined to, in a strict sense, ecological phenomena, such as spatial or temporal separation of resource use, herbivore-mediated suppression of dominants, or chance effects during recruitment. An alternative (or complementary) view of diversity in communities stresses importance of historic, or phylogenetic, aspects of species diversification. Present-day diversity is a result of speciation and extinction processes that have occurred over long time. In his overview of diversity in land communities, Whittaker (1977) concluded that there is not much evidence, either theoretical or empirical, for that species diversity is in equilibrium. Hence, in Whittakers view, to understand patterns of diversity, large scale aspects of speciation, extinction and biogeography must be accounted for. This line of reasoning can be exemplified by some studies of diversity in tropical rain forests. These communities are well known for their exceptional plant species richness (Gentry 1982), and one general explanation for their high diversity is that tropical forests have accumulated species under stable conditions experienced during long time (Stebbins 1974). In a study of tropical tree species diversity, Hubbell and Foster (1986) suggested that tree communities are in a state of non-equilibrium; new species' (either immigrants or newly evolved ones) are capable of invading communites due to a permanent occurrence of empty sites. Since risk of species exclusion from a plant community was found to be very small, diversity would be determined by regional species richness and immigration rates. Thus, variation in species diversity among communities, or among guilds within communities, reflect rate-determining mechanisms behind speciation and extinction. High species diversity is expected when existing speciespool contains many species, and comparatively low species diversity will be found when species-pool is small. Similar suggestions have been made by several authors, in various contexts, (e.g. Grime 1973, 1979, Cracraft 1985, Hodgson 1986, 1987, Connell and Lowman 1989, Hart 1990, Brooks and McLennan 1991, Cornell and Lawton 1992, Zobel 1992), and Taylor et al. (1990) coined term the species-pool hypothesis for explanations of local diversity by reference to size of regional or global pool of species: All else being equal, larger local and/or global area of a habitat type and older its geological age, greater past opportunity for speciation and hence, greater number of available species adapted to a particular habitat type. However, if different phylogenetic lineages do not diversify at same average rate, age (or size) of a habitat type may be only weakly related to richness of species-pool. Furthermore, Zobel (1992) stressed importance of evolutionary factors (i.e. speciation rate) in explanations of species diversity in plant communities, but did not specify what might determine speciation rate per se. Cracraft (1985) approached diversity problem from a different angle and suggested that community diversity is explicable by basic processes speciation and extinction; speciation rates are mainly determined by large scale changes in lithospheric complexity, and extinction rates are dependent on envi-

The information about the distribution of caddisflies (Trichoptera) in mid-western Poland being a part of the Wielkopolsko-Kujawska Lowland (WKL) faunistic region is still scarce compared to other regions. To close the knowledge gap, we investigated caddisflies larvae and occasionally imagines in a selected area in mid-western Poland in 2011. The aim was the preliminary estimation of species richness and abundance of protected, rare and endangered species in this part of WKL. For the study 63 sampling sites representing broad spectrum of habitat types were chosen and analysed with various ecological indices. In total, 75 species: 46 as larvae and 51 as imagines were found in the area. Among them, one protected species (Crunoecia irrorata), 5 listed in the Polish Red List (Erotesis baltica, Hydropsyche bulgaromanorum, Ylodes simulans, Limnephulus borealis and L. fuscinervis), and 11 species not reported for WKL yet were found in the area. In the whole material, the most frequent and dominant species was Limnephilus flavicornis. In contrast, 50 species were recorded in less than 5% of sites. The highest species richness was found in rivers and fish ponds with total number of 33 and 32 species, respectively, whereas the lowest one in springs (5 species) and bogs (6 species). The highest species diversity obtained with probability of intraspecific encounter (PIE) Index was found in fish ponds (0.90) and rivers (0.85) as well. In contrast, streams had the lowest PIE value (0.60) in the area. The most valuable habitat types with regard to protected, endangered and rare species were rivers and fish ponds, as well as lakes and streams of lower importance. To conclude, our investigation indicated a high species richness and diversity in the area, which was related to high habitat heterogeneity, thus having significant importance for biodiversity preservation in mid-western Poland. Moreover, fish ponds and rivers were the most valuable habitat types significantly contributing to species richness, diversity and preservation of rare and endangered species in this area.

Tree-related microhabitats (TreMs) describe the microhabitats that a tree can provide for a multitude of other taxonomic groups and have been proposed as an important indicator for forest biodiversity. So far, the focus of TreM studies has been on temperate forests, although the tropics provide a large forest area, with different types of forest and a high diversity of tree species, some of them with exceptionally high numbers of TreMs. In this study, TreMs in the lowland tropical forests of the Chocó (Ecuador) and in the mountain tropical forests of Mount Kilimanjaro (Tanzania) were surveyed. Our results extend the existing typology of TreMs of Larrieu et al. (2018) to include tropical forests and enabled a comparison of the relative recordings and diversity of TreMs between tropical and temperate forests. A new TreM form, Root formations, and three new TreM groups, concavities build by fruits or leaves, dendrotelms, and root formations, were established. In total, 15 new TreM types in five different TreM groups were specified. The relative recordings of most TreMs were similar between tropical and temperate forests. However, ivy and lianas, and ferns were more common in the lowland rainforest than in temperate forests, and bark microsoil, limb breakage, and foliose and fruticose lichens in tropical montane forest than in lowland rainforest. Mountain tropical forests hosted the highest diversity for common and dominant TreM types, and lowland tropical forest the highest diversity for rare TreMs. Our extended typology of tree-related microhabitats can support studies of forest-dwelling biodiversity in tropical forests. Specifically, given the ongoing threat to tropical forests, TreMs can serve as an additional tool allowing rapid assessments of biodiversity in these hyperdiverse ecosystems.

Threatened tree species across conservation zones in a nature reserve of North-Western Vietnam

Ecological mechanisms proposed to explain community assembly and the maintenance of biodiversity are hypothesized to fall along a theoretical continuum bounded at one extreme by deterministic processes (“niche assembly”) and at the other extreme by stochastic processes (“dispersal assembly”). In this dissertation, I explore the idea that the position of ecological communities along the niche-dispersal assembly continuum is dynamic in space and time. Using field experiments in a high-diversity longleaf pine savanna, I test the general hypothesis that “ecological filters” (competition, disturbance, and resource availability) contribute to niche assembly through their effects on established plant species and recruitment from the species pool. Consistent with dispersal-assembly theory, I found that dispersal from the species pool strongly limited local species diversity regardless of the presence of these three niche-based ecological filters. Importantly, however, some ecological filters (e.g., space limitation in communities with low-intensity fire disturbance and establishment limitation imposed by drought and high-rainfall conditions) limited the extent to which community assembly was influenced by dispersal, suggesting ecological conditions that reduce stochastic community assembly in high-diversity communities. I examined the generality of these patterns by conducting a meta-analysis of >60 published experiments. I found that dispersal strongly limited species richness in a wide range of plant communities, but that dispersal had a stronger positive effect on species richness in more disturbed communities and when the species pool contained high species diversity and functional-trait diversity, supporting the hypothesis that community assembly reflects a dynamic interplay between species-pool diversity and local environmental heterogeneity. My results suggest a conceptual model for community assembly in high-diversity pine savannas, with implications for other species-rich plant communities. I propose that characteristics of high-diversity communities (large species pools and pervasive recruitment limitation in populations of many rare species) generally contribute to stochastic community assembly, but that niche-based ecological filtering of resident species and immigrating species can shift high-diversity communities towards more deterministic community assembly. This conceptual framework has broader implications for understanding the maintenance of biodiversity and species coexistence in communities of contrasting diversity and for conserving biodiversity in longleaf pine communities threatened by habitat loss, fragmentation, and environmental change.

Summary The Janzen–Connell hypothesis (JC) is one potential mechanism to explain the maintenance of high alpha diversity of tree species in tropical forests, operating through differential pressure by natural enemies. We proposed that this differing pressure could arise from the richness of damage types due to natural enemies (RDNE). Following a community compensatory trend (CCT), we hypothesized greater RDNE on common species than on rare species. We evaluated this novel interpretation of the JC by assessing damage patterns on leaves, as a proxy for natural enemy species in 44 tree species. We first evaluated which abiotic and biotic factors affect RDNE. Then, we tested whether increasing RDNE leads to an increasing amount of foliar damage. We found that RDNE Was affected by biotic environments: RDNE increased with mean seedling species abundance. RDNE was higher on species occurring near more closely related neighbours. Was not impacted by abiotic factors. Yet, seedlings of shade‐tolerant species hosted a higher RDNE than seedlings of shade‐intolerant species. Was positively correlated with amount of foliar damage at the species level. Finally, we tested whether RDNE increased seedling mortality risk. We found that Foliar damage, species abundance and RDNE2 increased mortality risk. Richness of damage types due to natural enemies linearly decreased mortality risk more strongly than RDNE2 increased it. Seedling age decreased mortality risk. Synthesis. The richness of damage types due to natural enemies increased with abundance of the host species, suggesting an important role of enemy diversity in the maintenance of tree diversity. Supporting a novel interpretation of the Janzen–Connell hypothesis, we found a greater mortality risk with increasing RDNE2, but not with increasing RDNE. There was a stronger negative linear effect of RDNE on mortality risk. Rare species with low RDNE as well as species with very high RDNE suffered greater mortality than species hosting intermediate RDNE, reinforcing the complexity of the effect of multiple enemies on prey.

Current research efforts to understand the relative invasibility of different plant communities have mostly ignored tropical forests. Only a few studies have treated invasive species in tropical forests, and recent worldwide analyses have not provided clear predictions concerning the relative invasibility of tropical forests. In this review, the extent to which exotic species have invaded tropical forests is summarized and four leading hypotheses to explain the apparently low frequency of invading plants in tropical forests are evaluated. In general, it is found that invasibility positively correlates with human disturbance, and that undisturbed tropical forests harbour few exotic species. To date, there is no evidence to attribute the low invasibility of undisturbed tropical forests to either their high species diversity or their high diversity of functional types. Instead, the low occurrence of exotic species in most tropical forests is most likely due to the fact that the great majority of exotic species that are transported to tropical countries lack specific life history traits, most importantly shade tolerance, necessary for successful invasion of undisturbed tropical forests. Unfortunately, this situation could change in the future with the expected increase in the plantation forestry of high-grade timber combined with common forestry practices that favour the cultivation of exotic species.

Species coexistence is a result of biotic interactions, environmental and historical conditions. The Janzen-Connell hypothesis assumes that conspecific negative density dependence (CNDD) is one of the local processes maintaining high species diversity by decreasing population growth rates at high densities. However, the contribution of CNDD to species richness variation across environmental gradients remains unclear. In 32 large forest plots all over the Japanese archipelago covering > 40,000 individual trees of > 300 species and based on size distributions, we analysed the strength of CNDD of individual species and its contribution to species number and diversity across altitude, mean annual temperature, mean annual precipitation and maximum snow depth gradients. The strength of CNDD was increasing towards low altitudes and high tree species number and diversity. The effect of CNDD on species number was changing across altitude, temperature and snow depth gradients and their combined effects contributed 11–18% of the overall explained variance. Our results suggest that CNDD can work as a mechanism structuring forest communities in the Japanese archipelago. Strong CNDD was observed to be connected with high species diversity under low environmental limitations where local biotic interactions are expected to be stronger than in niche-based community assemblies under high environmental filtering.

The species diversity data of seven globally important wetlands (Canadian peatlands, Florida Everglades, Pantanal, Okavango Delta, Sundarban, Tonle Sap, and Kakadu National Park) were compared. The available data for most groups of lower plants and animals are insufficient for a comparative analysis. Data on vertebrates and higher plants are more complete and show high species diversity. The large habitat diversity allows the coexistence of amphibious species with many immigrants from connected deepwater and terrestrial habitats. Several of these immigrant species find an important permanent refuge in the wetlands; some use the wetlands as periodic habitats. All wetlands are important habitats for long-distance migratory bird species. The species composition reflects the biogeography of the respective regions, e.g. the high diversity of large ungulates characteristic for Africa is also found in the Okavango Delta in Botswana, and the high fish species diversity typical for South America is also reflected in the Pantanal in Brazil. The number of endemic species in most wetlands is low, except in the Everglades. The low numbers are explained to some extent by the dramatically changing paleo-climatic conditions that increased extinction rates, but also by the connection with large river systems that act as migratory and transport routes for species from large catchment areas and hinder the genetic isolation of wetland populations. The high number of endemic species in the Everglades is explained in part by its isolation on a peninsula. The relatively low nutrient status of most wetlands does not negatively affect species diversity and often leads to high animal densities. Large populations of endangered or rare species in all wetlands contribute to the great value of these areas for biodiversity protection. All wetlands are subjected to an increasing degree to human pressure through, e.g. water abstraction, changes in the natural flood regime, land reclamation, pollution, over-utilization of natural resources, and poaching. High habitat diversity and a pronounced natural disturbance regime make some of the wetlands vulnerable to invasion by exotic species, as shown for the Everglades. All studied wetlands are at least in part protected by national and international conventions. This provides perspectives for long-term protection only to a limited extent because of major environmental changes in their surroundings. Further strong efforts are required to match protection and sustainable use of the wetlands proper with management activities in their catchments.

Land use, habitat suitability, and seasonality can fundamentally shape small-mammal abundance, species richness, diversity, evenness, and composition. However, how these characteristics of small mammals are determined by land use, habitat type, and rainfall seasonality is still poorly understood for most ecosystems. We analyze how land use (protection in a national park, pastoralism, and crop agriculture), habitat type, and rainfall seasonality influence small-mammal relative abundance, species richness, and diversity in the Tanzania Serengeti Ecosystem. We used 141 live traps to capture 612 small mammals in the wet and dry seasons of 2017 and 2018. Relative abundance was higher in the pastoral land than in the park or agricultural land and in the dry season in all the three land use types. Species richness and diversity were highest in the park, middling in the agricultural land, and lowest in the pastoral land. The high relative abundance in the pastoral land was primarily due to the numerical dominance of two generalist species in the shrubland (grass rat Arvicanthis niloticus) and cropland (multimammate rat Mastomys natalensis), resulting in low species richness and diversity. High species richness and diversity in the park indicate high habitat heterogeneity, whereas high species diversity in the agricultural land during the dry season reflects high food availability during and soon after harvests. Thus, human activities apparently exert deleterious effects on some specialist small mammals as a result of reduced habitat heterogeneity while promoting the abundance of some generalist species in African savanna ecosystems. However, increased abundance of generalist species reduces small mammal species diversity while increasing the risk of human–small mammal conflicts. We offer several testable hypotheses motivated by our results.

Composition, diversity and distribution of woody species in relation to vertical stratification of a tropical wet evergreen forest in Bangladesh

The relationship between plant biodiversity and soil chemical fertility has been widely investigated in temperate forests and agroecosystems, but there is lack of information about the correlation between these two variables in tropical forests. In this study, the relationship between plant biodiversity and soil chemical fertility was analyzed in a mature tropical forest in Costa Rica. Soil samples were collected in 9 sampling plots (5 m by 25 m) in order to identify the concentration level of P, K, Ca, Mg, Fe, Zn, Mn, and Cu, the soil fertility index, the CEC, and the C/N ratio. Furthermore, species richness, Shannon-Wiener and Simpson’s species diversity, structural richness, and structural diversity were determined for each of the 9 sampling plots. Simple linear regression analysis was used to determine if there was a significant relationship between any of the different variables of plant biodiversity and soil chemical fertility. Tree species richness was inversely related to concentration levels of K, Ca, and P, CEC, and soil fertility index. These results agree with the few studies that were done in tropical ecosystems. Higher tree species richness tended to be found in sites with lower soil fertility. Shannon-Wiener tree species diversity was positively correlated to C/N ratio. This is a new discovery and it seems that there is less N stored in organic matter compared to C in sites with higher species diversity. Herb structural richness was positively related to soil fertility index and P concentration. The herb community may be able to grow taller in soil with higher P content and soil fertility leading to higher structural richness because P is the main soil factor limiting growth in tropical ecosystems. There was a positive relationship between herb structural diversity and Mn concentration in the soil. Therefore, structural diversity is not affected much by soil fertility. No relationship was found among any of the other variables. This study gives important insights on the ecological relationship between plant biodiversity and soil chemical fertility in primary tropical forest stands.

Tropical forests are the most productive terrestrial ecosystems, fixing over 40 Pg of carbon from the atmosphere each year. A substantial portion of this carbon is allocated below‐ground to roots and root‐associated micro‐organisms. However, there have been very few empirical studies on the dynamics of this below ground transfer, especially in tropical forests where carbon allocation processes are influenced by high plant species diversity. We used a whole‐stand girdling experiment to halt the below‐ground transfer of recent photosynthates in a lowland tropical forest in Borneo. By girdling 209 large trees in a 0.48 ha plot, we determined: (a) the contribution of recent photosynthate to root‐rhizosphere respiration and; (b) the relationships among the disruption of this below‐ground carbon supply, tree species composition and mortality. Mortality of the 209 trees was 62% after 370 days, with large variation among species and particularly high mortality within the Dipterocarpaceae (99%) and Fagaceae (100%) families. We also observed a higher risk of mortality following girdling for species with lower wood density. Soil CO2 emissions declined markedly (36 ± 5%) over ~50 days following girdling in three of six monitored subplots. In the other three subplots there was either a marginal decline or no response of soil CO2 emissions to girdling. The decrease in soil CO2 efflux was larger in subplots with dominance of Dipterocarpaceae. Synthesis. Our results indicate high spatial variation in the coupling of below‐ground carbon allocation and root‐rhizosphere respiration in this tropical forest, with a closer coupling in forest dominated by Dipterocarpaceae. Our findings highlight the implications of tree species composition of tropical forests in affecting the dynamics of below‐ground carbon transfer and its release to the atmosphere.

The information about the distribution of caddisflies (Trichoptera) in mid-western Poland being a part of the Wielkopolsko-Kujawska Lowland (WKL) faunistic region is still scarce compared to other regions. To close the knowledge gap, we investigated caddisflies larvae and occasionally imagines in a selected area in mid-western Poland in 2011. The aim was the preliminary estimation of species richness and abundance of protected, rare and endangered species in this part of WKL. For the study 63 sampling sites representing broad spectrum of habitat types were chosen and analysed with various ecological indices. In total, 75 species: 46 as larvae and 51 as imagines were found in the area. Among them, one protected species (Crunoecia irrorata), 5 listed in the Polish Red List (Erotesis baltica, Hydropsyche bulgaromanorum, Ylodes simulans, Limnephulus borealis and L. fuscinervis), and 11 species not reported for WKL yet were found in the area. In the whole material, the most frequent and dominant species was Limnephilus flavicornis. In contrast, 50 species were recorded in less than 5% of sites. The highest species richness was found in rivers and fish ponds with total number of 33 and 32 species, respectively, whereas the lowest one in springs (5 species) and bogs (6 species). The highest species diversity obtained with probability of intraspecific encounter (PIE) Index was found in fish ponds (0.90) and rivers (0.85) as well. In contrast, streams had the lowest PIE value (0.60) in the area. The most valuable habitat types with regard to protected, endangered and rare species were rivers and fish ponds, as well as lakes and streams of lower importance. To conclude, our investigation indicated a high species richness and diversity in the area, which was related to high habitat heterogeneity, thus having significant importance for biodiversity preservation in mid-western Poland. Moreover, fish ponds and rivers were the most valuable habitat types significantly contributing to species richness, diversity and preservation of rare and endangered species in this area.