Showing papers in "Biodiversity and Conservation in 2001"
TL;DR: Characteristics associated with insect responses to fire related to the degree of exposure to lethal temperature and stress experienced in the post-fire environment, suitability of post-treatment vegetation as habitat, and ability to rebuild numbers in the site (from survivors and/or colonizers) appear equally useful for explicating insect responsesto other managements such as haying, mowing, and grazing.
Abstract: This literature review concerns insect responses to fire, compared to other feasible and appropriate conservation managements of open habitats. Many insect groups decline markedly immediately after fire, with the magnitude of reduction related to the degree of exposure to the flames and mobility of the insect. Niche diversity is lower in recently burned habitat, and the rate of insect increase following fire also relates to the species' ability to gain access to the regrowing vegetation. Postburn flora can be quite attractive to some recolonizing insects, possibly to some degree a result of fire-caused insect mortality which provides plants with short-term release from insect herbivory. Insect declines may follow immediately after mowing, but usually of lesser degree and shorter duration than after a fire of comparable timing and size. Season and scale of cutting may affect how much and which species showed positive or negative responses. Cut areas offer the vegetational structure and composition preferred by some insects, but cutting – or cutting at certain scales, seasons, or frequencies – may also be unfavorable for some species. Heavy grazing results in niche and assemblage simplification. Nonetheless, some invertebrates prefer the short turfs and bare ground resulting from heavier grazing. Other species vary in whether they peak in abundance and diversity in intermediate, light, or no grazing. In comparisons of mowing/haying and grazing regimes of similar compatibility with maintenance of the same habitat types, responses of particular species and species groups varied as to whether they had a preference for one or the other. Characteristics associated with insect responses to fire related to the degree of exposure to lethal temperature and stress experienced in the post-fire environment, suitability of post-treatment vegetation as habitat, and ability to rebuild numbers in the site (from survivors and/or colonizers). These factors appear equally useful for explicating insect responses to other managements such as haying, mowing, and grazing. By contrast, the assumption that the most habitat-restricted species will be most adapted to ecological forces believed to be prevalent in that ecosystem appears less efficacious for predicting insect management preferences.
422 citations
TL;DR: In this article, the authors present a conceptual model for urban bird conservation, which includes three aspects (management, environmental education and research) and new alternatives to promote the involvement of different sectors of the society.
Abstract: Wildlife conservation in urban habitats is increasingly important due to current urbanization trends. We review the different approaches to studying birds in urban landscapes, and point out the impor- tance of the habitat island ecological theory as a research framework for the management and conservation of urban birds. Based on two comprehensive research projects conducted at urban parks in Spain (Ma- drid) and Finland (Oulu and Rovaniemi), several different issues related to bird conservation in cities are discussed, main findings of these projects are presented, and future research needs are suggested. Urban parks are important biodiversity hotspots in cities. Fragmentation conditions have the same deleterious effects to urban birds as in other fragmented landscapes. Park size accounts for species accumulation in urban parks; this pattern being highly nested. Urban parks of 10-35 ha would contain most of the species recorded in cities, but other indicators related to the probabilities of persistence of the target species should be obtained. Wooded streets can increase urban landscape connectivity by providing alternative habitat for feeding and nesting during the breeding season. Because increasing the size of parks is difficult in cities, enhancement of habitat diversity and resource availability for birds within parks (e.g. nest boxes, winter feeding tables, etc.) appears to be a straightforward way of increasing urban bird diversity. However, human disturbance (pedestrians) should be controlled since it can negatively influence many urban birds. We present a conceptual model for urban bird conservation, which includes three aspects (management, environmental education and research) and new alternatives to promote the involvement of different sectors of the society.
382 citations
TL;DR: The results strongly advise against using a single-taxon approach to design management and conservation actions in semi-natural pastures, and the importance of landscape composition for mobile organisms such as birds entails that management activities should focus on the wider countryside and not exclusively on single pastures.
Abstract: The preservation of remaining semi-natural grasslands in Europe has a high conservation priority Previously, the effects of artificial fertilisation and grazing intensity on grassland animal and plant taxa have been extensively investigated In contrast, little is known of the effects of tree and shrub cover within semi-natural grasslands and composition of habitats in the surrounding landscape on grassland taxa We evaluated the effect that each of these factors has on species richness and community structure of vascular plants, butterflies, bumble bees, ground beetles, dung beetles and birds surveyed simultaneously in 31 semi-natural pastures in a farmland landscape in south-central Sweden Partial correlation analyses showed that increasing proportion of the pasture area covered by shrubs and trees had a positive effect on species richness on most taxa Furthermore, species richness of nectar seeking butterflies and bumble bees were negatively associated with grazing intensity as reflected by grass height At the landscape level, species richness of all taxa decreased (butterflies and birds significantly so) with increasing proportion of urban elements in a 1-km2 landscape area centred on each pasture, while the number of plant and bird species were lower in landscapes with large proportion of arable fields Our results differed markedly depending on whether the focus was on species richness or community structure Canonical correspondence analyses (CCA) showed that the abundance of most taxa was ordered along a gradient describing tree cover within pastures and proportion of arable fields in the landscape However, subsets of grassland birds and vascular plants, respectively, showed markedly different distribution patterns along axis one of the CCA In contrast to current conservation policy of semi-natural pastures in Sweden, our results strongly advise against using a single-taxon approach (ie, grassland vascular plants) to design management and conservation actions in semi-natural pastures Careful consideration of conservation values linked to the tree and shrub layers in grasslands should always precede decisions to remove trees and shrubs on the grounds of promoting richness of vascular plants confined to semi-natural grasslands Finally, the importance of landscape composition for mobile organisms such as birds entails that management activities should focus on the wider countryside and not exclusively on single pastures
349 citations
TL;DR: Advances of first-flowering in these 89 species are directly correlated with local increase in minimum temperature (Tmin), which is inferred from spring advances in first- Flowering in plants.
Abstract: Evidence for global warming is inferred from spring advances in first-flowering in plants. The trend of average first-flowering times per year for the study group shows a significant advance of 2.4 days over a 30-year period. When 11 species that exhibit later first-flowering times are excluded from the data set, the remaining 89 show a significant advance of 4.5 days. Significant trends for earlier-flowering species range from -3.2 to -46 days, while those for later-flowering species range from +3.1 to +10.4 days. Advances of first-flowering in these 89 species are directly correlated with local increase in minimum temperature (T
min).
262 citations
TL;DR: China is a vast country with rich biodiversity, which makes China especially vulnerable to invasive species, and two example industries have brought or tend to bring in many invasive species and hence have caused or will cause changes and loss of biodiversity in local ecosystems.
Abstract: China is a vast country with rich biodiversity, which makes China especially vulnerable to invasive species. It has a long history of introduction of non-native species, especially those with perceived beneficial impacts. Its rapid economic development, including an explosive growth in international trade and transportation, has increased the potential for new introductions. Currently, alien species are widespread in the country, occur in many ecosystems, represent most major taxonomic groups, and are introduced unintentionally as well as intentionally for cultivation. The paper lists various cases of invasive species which have caused significant threats or damages to local natural or artificial ecosystems, and indicates that two example industries (fresh water fisheries and lawn grasses) have brought or tend to bring in many invasive species and hence have caused or will cause changes and loss of biodiversity in local ecosystems. Based on these studies, it is suggested that China combat the problem through enhancing awareness, development of a database on invasive species, strengthening international co-operation, preparing case studies and introducing the necessary legislation, regulations and monitoring.
257 citations
TL;DR: It is concluded that negative ecosystem impacts of purple loosestrife in North America justify control of the species and that detrimental effects of purple tightenedrife on wetland systems and biota and the potential benefits of control outweigh potential risks associated with the introduction of biocontrol agents.
Abstract: The invasion of non-indigenous plants is considered a primary threat to integrity and function of ecosystems. However, there is little quantitative or experimental evidence for ecosystem impacts of invasive species. Justifications for control are often based on potential, but not presently realized, recognized or quantified, negative impacts. Should lack of scientific certainty about impacts of non-indigenous species result in postponing measures to prevent degradation? Recently, management of purple loosestrife (Lythrum salicaria), has been criticized for (1) lack of evidence demonstrating negative impacts of L. salicaria, and (2) management using biocontrol for lack of evidence documenting the failure of conventional control methods. Although little quantitative evidence on negative impacts on native wetland biota and wetland function was available at the onset of the control program in 1985, recent work has demonstrated that the invasion of purple loosestrife into North American freshwater wetlands alters decomposition rates and nutrient cycling, leads to reductions in wetland plant diversity, reduces pollination and seed output of the native Lythrum alatum, and reduces habitat suitability for specialized wetland bird species such as black terns, least bitterns, pied-billed grebes, and marsh wrens. Conventional methods (physical, mechanical or chemical), have continuously failed to curb the spread of purple loosestrife or to provide satisfactory control. Although a number of generalist insect and bird species utilize purple loosestrife, wetland habitat specialists are excluded by encroachment of L. salicaria. We conclude that (1) negative ecosystem impacts of purple loosestrife in North America justify control of the species and that (2) detrimental effects of purple loosestrife on wetland systems and biota and the potential benefits of control outweigh potential risks associated with the introduction of biocontrol agents. Long-term experiments and monitoring programs that are in place will evaluate the impact of these insects on purple loosestrife, on wetland plant succession and other wetland biota.
246 citations
TL;DR: Terrestrial molluscs, some vascular forest plants, and those bryophytes and lichenized fungi classified as 'perennial stayers' in life history strategy classification, might be used to indicate long-term habitat persistence in forests, but more research is needed to evaluate such indicators.
Abstract: Very old, undisturbed forest stands may be important for biodiversity through their content of microhabitats or for the long periods available for colonisation, or for both. The term Ecological Continuity (EC) has been used to ascribe value to old forest stands. The relative importance of microhabitat and time for colonisation are usually not kept apart when EC is used as a conservation criterium. EC is broadly applied but poorly defined. Use of EC may lead to underestimation of the importance of forest dynamics and dispersal, and to overestimation of the importance of local land use history. If bioindicators of long- term habitat persistence are to be used, species with low dispersal capacity should be chosen. However, many lichens and other fungi, bryophytes and insects cited as indicators of EC, seem to have a patch- tracking lifestyle. They are 'colonists' according to life history strategy classification, and rather seem to indicate specific microhabitats. Terrestrial molluscs, some vascular forest plants, and those bryophytes and lichenized fungi classified as 'perennial stayers' in life history strategy classification, might be used to indicate long-term habitat persistence in forests, but more research is needed to evaluate such indicators.
213 citations
TL;DR: The importance local people accorded to each species was compared to the number of its uses, number of people using it, and other aspects of its use, and it was concluded that even if important palms are used for more purposes than less important palms, they owe their importance to one or two of their main uses.
Abstract: Madagascar's palm flora is very diverse (171 species) and has a high degree of endemism (97%). Palm products make an important contribution to the household economy of many rural families, especially in the palm-rich eastern escarpments. Many palms are, however, threatened by overexploitation and habitat destruction. We investigated which palm species were found and used in three villages on the eastern escarpments of Madagascar. The importance local people accorded to each species was compared to the number of its uses, number of people using it, and other aspects of its use. From this comparison it was concluded that even if important palms are used for more purposes than less important palms, they owe their importance to one or two of their main uses. We also investigated if there were any patterns in the distribution of informants' knowledge and whether such patterns could be related to socio-economic factors. There was a positive relationship between knowledge about palms and personal wealth and a negative relationship between distance to the forest and amount of knowledge. The latter can be a sign of an ongoing knowledge erosion. Sustainable use of native palms should be encouraged as it may contribute positively to village economy and knowledge preservation, and may provide incentives for preservation of remaining forest tracts.
187 citations
TL;DR: The results imply that conservation measures should focus on zonal forests in a few large reserves at low and mid-elevations and in many smaller reserves at higher elevations.
Abstract: Patterns of point, α-, and β-diversity, and of an index of range size were studied for Acanthaceae, Araceae, Bromeliaceae, Melastomataceae, Palmae, and Pteridophyta in 204 vegetation plots of 400 m2 along an elevational gradient in humid montane forest at 220–3950 m in central Bolivia. Zonal forest point-diversity (mean species number per plot) and α-diversity (extrapolated total species number) showed either hump-shaped curves or constant values from lowlands to mid-elevations, followed by a steep decline. These patterns correspond to the hypothesis of maximum diversity at intermediate levels of productivity, while for pteridophytes and epiphytic Bromeliaceae they also fitt a null-model of random distribution within bounded geographical ranges. The ratio of point to α-diversity was surprisingly constant across study groups and elevation with values of 0.2–0.4. Range size index (mean inverse range size of all species recorded at a given elevation) either increased with elevation, showed hump-shaped patterns, or remained roughly constant. Non-zonal habitats (ravines, ridge-tops, rock faces, roadsides, pastures) contributed significantly to overall species number for terrestrial herbs and shrubs of Bromeliaceae, Melastomataceae, and Pteridophyta, but not for Acanthaceae, Araceae, and epiphytic taxa. With few exceptions, endemism was most pronounced in zonal forests. These results imply that conservation measures should focus on zonal forests in a few large reserves at low and mid-elevations and in many smaller reserves at higher elevations.
184 citations
TL;DR: Dragonfly species richness appears to be positively associated with species richness of vascular plants, and nestedness matrices are proposed to be a good selecting tool for indicator species, particularly in groups where the biology of the species is not well known.
Abstract: We argue the need to select indicator species on empirical data to avoid influence of personal opinions. To test an empirical selection process based on a nested subset matrix, we sampled partivoltine dragonfly larvae from 74 small lakes in central Sweden. A nestedness matrix was set up using the 'nestedness temperature calculator' program, selecting 11 species as potential indicators of species richness. These were tested against a known indicator species for water quality (the pool frog) and plant diversity through inventories and comparison to existing surveys of biological values ('rich' lakes vs. 'ordinary' lakes). We could only see a trend towards the pool frog occurring in dragonfly-rich lakes, but found a significant connection between the number of aquatic plants along the shore line and the number of dragonfly species present. A significantly higher number of indicators were encountered in lakes previously surveyed as 'rich' in plants than in lakes classified as 'ordinary'. Dragonfly species richness therefore appears to be positively associated with species richness of vascular plants. We propose nestedness matrices to be a good selecting tool for indicator species, particularly in groups where the biology of the species is not well known. However, it is important to define what such indicators really indicate.
175 citations
TL;DR: For the first time, 14 species of bats were reported from the Iwokrama International Rain Forest Programme site in central Guyana as mentioned in this paper, bringing the known bat diversity for the country to 121 species.
Abstract: Fourteen species of bats are reported for the first time from Guyana (Saccopteryx gymnura, Micronycteris brachyotis, M. homezi, Lichonycteris obscura, Anoura latidens, Vampyressa pusilla, Vampyrodes caraccioli, Eptesicus chiriquinus, Cynomops paranus, Molossops neglectus, Molossus sp., Molossus coibensis, Molossus sinaloae, and Promops centralis) bringing the known bat diversity for the country to 121 species. Information including measurements, reproductive data, distribution, and taxonomy are provided for these species. Seven of these new records were collected in the Iwokrama International Rain Forest Programme site in central Guyana. Eighty-six bat species are now documented from Iwokrama Forest which is the highest species diversity for bats reported from any protected area in the world. There are, however, few tropical sites that have relatively complete inventories. A summary for bat species diversity in southern Venezuela, Guyana, Suriname, and French Guiana indicates that at least 146 species of bats are known from the Guianan subregion. Intense inventory surveys, especially in the often neglected subcanopy, suggest that species richness is probably underestimated in most Neotropical areas. Likewise, species-level diversity in the Guianan subregion is higher than previously suggested. Surveying and monitoring biodiversity are critical to developing a National Protected Areas System in Guyana.
TL;DR: It is now evident that the high species richness and endemism observed 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.
Abstract: 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.
TL;DR: The results show that the high diversity of carabids in forest edges is due to the edge-associated species and the presence of species characteristic to the adjacent habitats.
Abstract: Diversity relationships of carabids in forest edges and the neighbouring forest interior and the surrounding grassland are studied. Samples were taken along three replicated forest-grassland transects using pitfall traps in the Aggtelek National Park in Hungary during 2 years. The study revealed significant edge effect on the carabids. The Shannon diversity of carabids were significantly higher in the forest edge and the grassland than in the forest interior. Carabids of the forest interior, forest edge and grassland can be separated from each other by ordinations, both on the species composition and abundance, suggesting that all three habitats have a distinct species assemblage. Moreover, indicator species analysis detected significant edge associated species; based on the specificity and fidelity of the carabids we have distinguished five groups of species: habitat generalists, grassland-associated species, forest generalists, forest specialists, and edge-associated species. Multiple linear regression analyses showed that relative air moisture, temperature of the ground and cover of the herbs are the most important factors determining the diversity of carabids along the transects. Our results show that the high diversity of carabids in forest edges is due to the edge-associated species and the presence of species characteristic to the adjacent habitats. The significance of forest edges in nature conservation, serving as a source habitat for dispersal processes, contributing to the recolonization of carabids after habitat destruction or other disturbance is emphasized.
TL;DR: The results corroborate the hypothesis that predicts that habitat stress is the main factor generating the patterns of galling insect richness in Brazilian savannas.
Abstract: Five hypotheses were tested to explain the pattern of galling insect species richness in four neotropical savanna physiognomies, 'canga ', 'campo sujo', 'cerrado' s. st., and 'cerradao', that occur in Minas Gerais, southeastern Brazil. We found 125 species of galling insects on 80 host plant species. The increase of plant species richness explained 35% of the variation in galling insect richness, corroborating the plant species richness hypothesis. Most of the galling species occurred on trees, followed by shrubs, and herbs. However, the difference in mean number of galls was only statistically significant between herbs and trees, corroborating partially the plant structural complexity hypothesis. A significant relationship was observed between galling species richness and density of herbs, and shrubs, corroborating partially the resource concentration hypothesis. Galling insect richness showed a negative correlation with magnesium, potassium, and zinc on soil, corroborating the soil fertility hypothesis. The content of magnesium, potassium, iron and CTC (T) explained 72% of the variation in galling insect richness. Plant family size positively influenced galling insect richness, corroborating the plant family size hypothesis. Overall, the results corroborate the hypothesis that predicts that habitat stress is the main factor generating the patterns of galling insect richness in Brazilian savannas.
TL;DR: Bird species richness at points in forest fragments did not decline with fragment size, distance from the reserve, or forest quality, however, forest in fragments was more heavily degraded than forest within the reserve and poor forest quality may be the cause of declines in some species.
Abstract: Little of Brazil's remaining Atlantic forest is protected, so it is important to assess how well the region's wildlife can persist in areas/habitats outside reserves. We studied bird diversity and abundance during 546 point counts in the Sooretama/Linhares reserve, 200 point counts in 31 forest fragments (10- 150 h), and 50 point counts in <30-year-old Eucalyptus plantations, within 7 km of the reserve. Only eight bird species were recorded in Eucalyptus, and this impoverishment, as compared to some Eucalyptus plantations elsewhere in Brazil may be a result of intensive clearance of understory vegetation. Species diversity in forest fragments was significantly lower than in the reserve. Twelve, mostly non-forest or edge species, were significantly commoner in the fragments, but nineteen species were frequent in the reserve but rare or absent in forest fragments. These included two Pyrrhura parakeets, a Brotogeris parakeet, a trogon Trogon, a jacamar Galbula, woodpeckers Piculus and Campephilus, Myrmotherula antwrens, and Hemithraupus and Tachyphonus tanagers. Bird species richness at points in forest fragments did not decline with fragment size, distance from the reserve, or forest quality. However, forest in fragments was more heavily degraded than forest within the reserve and poor forest quality may be the cause of declines in some species. Whilst protection of forest within reserves is a priority, management of forest fragments may aid conservation of some threatened species.
TL;DR: In this article, the authors proposed an optimal protected area network that is composed of forest blocks that are sufficiently large, intact, and likely to persist; and contains zones of active speciation (e.g. ecotones).
Abstract: Protected areas in the Congo Basin cover approximately 6% of the landscape, and several international NGOs are proposing substantial additions to the present network of parks and reserves. Yet, chronic under-funding has long precluded effective management of most parks and reserves resulting in their progressive ecological impoverishment, and the loss of biodiversity. Furthermore, not only are the indebted nations of the Congo Basin not in a position to contribute significantly to cover the recurring costs of protected area management, the growing opportunity costs of setting aside protected areas is increasing the incentives to local communities and national governments to 'illegally' exploit economically valuable resources within parks and reserves. If the global value of the biodiversity contained within the Congo Basin is considered worth preserving then donors and international NGOs must work with national governments to reach consensus on an optimal protected area network that (a) contains a representative assemblage of forest species; (b) is composed of forest blocks that are sufficiently large, intact, and likely to persist; (c) contains zones of active speciation (e.g. ecotones), and (d) can expect to receive sufficient long-term financial support to ensure effective management. Given the 'need to eat today' reality of economies in the Congo Basin, the international community must decide to shoulder most of the costs of conservation of globally important biodiversity. If donors continue to under-finance protected areas rather than make the hard choices associated with prioritizing protected area spending then most if not all protected areas within the Congo Basin will continue to exhibit reductions in the biomass of individual species, and risk the extirpation or extinction of large, slow reproducing species, and rare endemics.
TL;DR: This paper found that reserve size correlates with local human density, such that small reserves are indeed significantly more likely than are large reserves to be located in regions of high human density (n = 169; P < 0.0001).
Abstract: Small reserves are especially likely to lose species. Is that because the reserves are small, or because small reserves are located in especially adverse landscapes? It seems that the question has rarely, if ever, been asked. Data on reserve size and location in Africa, and calculations of local (within 50 km) mean human densities from available census records per province per country were the database here used to answer the question. IUCN grade I and II reserves in Africa are located across the range of human densities per country, including in regions of higher than average density. Furthermore reserve size correlates with local human density, such that small reserves are indeed significantly more likely than are large reserves to be located in regions of high human density (n = 169; P < 0.0001). However, while local human density correlates significantly with human-caused mortality of carnivores (the only taxon for which we had data), it does not correlate with detected extinctions in reserves in east Africa (the only region with available data). Rather, area of reserve is the main predictor. Nevertheless, abundant other evidence of the adverse effects of high human density on persistence of species and wilderness indicates that we need to take as a warning the findings reported here that small reserves occur in regions of high human density, and that human density correlates with human-caused mortality. They indicate that small reserves might face the double jeopardy of both their small size, and also their situation in especially hostile surroundings. In effect, small reserves are more isolated in more adverse habitat than current analyses in conservation biology, landscape ecology, or metapopulation analysis usually indicate.
TL;DR: It is argued that this index, here referred to as a measure of ‘endemism richness’, can be regarded as the specific contribution of an area to global biodiversity and demonstrates that at a given sampling scale it shows a linear relation with area.
Abstract: The adjustment of an existing index which combines endemism and species richness (Williams 1993) is proposed so that it requires markedly less data on the study area and its flora or fauna than was necessary with the conventional calculation method. Using this adjusted method, the resulting scores are calculated and mapped for the seed plant flora of the 20 African regions as delineated by White (1983). We argue that this index, here referred to as a measure of ‘endemism richness’, can be regarded as the specific contribution of an area to global biodiversity. We demonstrate that at a given sampling scale it shows a linear relation with area. We further demonstrate that, within certain limits, this linearity can also be observed in many cases when sampling scales vary which makes the comparison of differently sized geographic units easier than is the case for species richness. The two most important advantages over species richness are that this index is more suitable to measure both the conservation value of an area and the negative impact of invaders. The latter quality is due to the fact that it yields scores which usually do not rise substantially but can rather be expected to drop in many cases when an area is invaded by alien species.
TL;DR: It appears that in most of the countries, pteridophyte diversity can be protected by focussing the most humid parts of the Andean forests.
Abstract: I assessed the magnitude and distribution of pteridophyte species richness on the eastern Andean slope in Bolivia based on 676 study plots of 400 m2 each in forest habitats at 65 study sites. In total 755 species were recorded, including 426 (56%) epiphytes and 598 (79%) terrestrials, with 266 species (35%) recorded under both groups. Mean number of species per plot at a given site varied from 0 to 31.1 for epiphytes, 0 to 20.9 for terrestrials, and 0 to 47.9 for all species combined. The highest numbers of species recorded at a given study site were 110 epiphytes, 101 terrestrials, and 167 species in total. While overall there were more terrestrial than epiphytic species, at individual sites and plots the reverse was true, indicating that terrestrial species tended to be more patchily distributed than epiphytes. Despite high survey intensity, many species went unrecorded; the minimum estimate of total species richness obtained through extrapolation was 975 species overall, including 559 epiphytes and 880 terrestrials. A correlation analysis of species richness to 14 environmental parameters revealed a highly positive correlation to mean annual precipitation and bryophyte cover on tree branches (a proxy for air humidity). Significant correlations to other parameters (e.g. human impact, canopy height, etc.) reflected the covariance of these factors with precipitation and bryophyte cover. Despite a lack of data on the pteridophyte communities from much of the Bolivian Andes, it appears that in most of the countries, pteridophyte diversity can be protected by focussing the most humid parts of the Andean forests.
TL;DR: Which value must be taken as an estimate of habitat species richness, the average or the cumulative α, and the implications that this decision can have in the evaluation of biodiversity are discussed.
Abstract: We test a strategy for analyzing species richness in a landscape. This strategy is based on the joint analysis of α (local), β (turnover) and γ (landscape) diversities. We assessed the spatial and temporal relations among α, β and γ diversity of bats (Phyllostomidae and Mormoopidae) in a tropical landscape. In a spatial dimension, γ diversity depends on the α diversity of the most species-rich community. The value of spatial β diversity between habitats was very low. A high α diversity was found in a cornfield, which may be attributed to the reduced extent of the field (compared with a more extensive field) that allows the arrival of individuals from nearby rich communities. In a temporal dimension, within habitat cumulative richness over sampling period may be considerably different from the average richness. These differences are attributed to temporal turnover during short time intervals. Therefore, cumulative richness may be viewed as the temporal equivalent of within-habitat γ diversity, which results of both average α and temporal turnover. We discuss, which value must be taken as an estimate of habitat species richness, the average or the cumulative α, and the implications that this decision can have in the evaluation of biodiversity.
TL;DR: Recognising the limitations of traditional botanic garden collections, it is proposed that botanic gardens more effectively utilise their two core competencies, namely scientific horticulture and public display and interpretation, to management of wild populations.
Abstract: Europe has the greatest concentration of botanic gardens in the world, they cultivate extensive collections of plants that include samples of European threatened plant species. This study looks at the effectiveness of these collections in supporting species conservation. A three part study is presented: (1) the results of a survey and assessment of threatened plants in botanic gardens, as defined by the Bern Convention; (2) case studies illustrating current issues in the ex situ management of European threatened plant species; and (3) presentation of policy recommendations on further improving botanic garden contributions to European plant conservation. The survey indicated that of 119 European botanic gardens in 29 European countries, 105 are cultivating 308 of the 573 threatened plant species listed by the Bern Convention. The survey identified 25 botanic gardens in 14 countries undertaking 51 conservation projects focused on 27 Bern listed species. In particular this survey has established that the majority of taxa are held in a small number of collections, dominated by non-wild origin accessions, and are not adequately documented. The majority of specimens in botanic gardens are cultivated out of the range country and not contributing to a specific conservation project. We review the genetic representation and documentation of origin in collections. Existing plant collections contain representatives of populations, now lost in the wild and maintain samples of at least nine European plant taxa identified as 'Extinct in the Wild'. However, inadequate standards of record keeping has compromised the conservation value of many collections. We highlight the dangers of hybridisation and disease in ex situ collections. The results suggest that botanic garden collections are skewed towards horticulturally robust and ornamental species and do not fully reflect priorities as defined by the Bern Convention. Recognising the limitations of traditional botanic garden collections we propose that botanic gardens more effectively utilise their two core competencies, namely scientific horticulture and public display and interpretation. The unique horticultural skills resident in European botanic gardens could be more effectively utilised through the application of horticulture to the management of wild populations.
TL;DR: In this article, the authors examined the relationship between waterbird use and habitat characteristics of farm ponds and concluded that the high number of farms in the transformed habitat matrix of the Western Cape plays an important role in conserving waterbirds.
Abstract: Natural freshwater wetlands are among the most threatened habitats on Earth. Effective wetland biodiversity conservation can not, however, be evaluated without fully understanding the roles of artificial waterbodies as refuges for water-dependent plants and animals. Waterbird assemblages were examined on 59 farm ponds in the Elgin and Caledon districts of the Western Cape, South Africa. This study examines the relationship between waterbird use and habitat characteristics of farm ponds. Patterns of temporal and spatial variation of waterbird species richness and abundance were quantified in relation to the habitat characteristics of each pond. Cluster analysis and multiple regression analyses identified surface area of the farm ponds as an important variable determining the presence and abundance of many waterbird species. Structural diversity in terms of vegetation in and around the ponds was especially important in determining their usage by waterbirds. These variables were evaluated in terms of creating a mosaic of habitat types (by varying vegetation structure and pond topography), which may be a useful way to enhance waterbird diversity at farm ponds. This study concludes that the high number of farm ponds in the transformed habitat matrix of the Western Cape plays an important role in conserving waterbirds.
TL;DR: In this paper, the effects of urban landscape composition on avian habitat selection at urban-parks edges were investigated, and the number of species, density of guilds and density of individual species varied between edge and interior habitats in six large wooded parks in Madrid (Spain).
Abstract: Few studies have investigated the effects of urban landscape composition on avian habitat selection at urban-park edges. I assessed how the number of species, density of guilds, and density of individual species varied between edge and interior habitats in six large wooded parks in Madrid (Spain), and analysed such patterns in relation to habitat structure, car traffic, and pedestrian traffic. Few differences in habitat structure were found; whereas car and pedestrian traffic were significantly higher at edges. Species foraging in trees and on the ground, and nesting in trees and in tree cavities had lower numbers and breeding densities at edges, probably as a result of the disturbance from traffic noise and pedestrians. Species highly habituated to human activities (House Sparrows Passer domesticus and Rock Doves Columba livia) displayed opposite patterns, with higher breeding densities at urban-park edges, probably due to their higher foraging opportunities (refuse, people leftovers, deliberate feeding) and nest site availability in adjacent buildings. Urbanisation sprawl may increase the prevalence of edge specialists and diminish the representation of species with specific habitat requirements.
TL;DR: In this article, a short observation period, 10% of humans and 39% of dogs disturbed birds on a Santa Barbara beach, and birds fledged when disturbed by humans and dogs.
Abstract: Use of a Santa Barbara beach by people and birds varied in both time and space. There were 100 birds, 18 people and 2 dogs per kilometer. Bird density varied primarily with the season and tide while human activity varied most between weekend and weekday. Bird distributions along the beach were determined mainly by habitat type (particularly a lagoon and exposed rocky intertidal areas) For crows and western gulls, there was some evidence that access to urban refuse increased abundance. Interactions between birds and people often caused birds to move or fly away, particularly when people were within 20 m. During a short observation period, 10% of humans and 39% of dogs disturbed birds. More than 70% of birds flew when disturbed. Bird species varied in the frequency that they were disturbed, partially because a few bird species foraged on the upper beach where contact with people was less frequent. Most disturbances occurred low on the beach. Although disturbances caused birds to move away from humans, most displacement was short enough that variation in human activity did not alter large-scale patterns of beach use by the birds. Birds were less reactive to humans (but not dogs) when beach activity was low.
TL;DR: In this paper, an experimental assessment of the effect of current agropastoral management on the biodiversity of plant communities was conducted during a six-year permanent plot survey in four sites with contrasting habitat conditions (mesic to xeric).
Abstract: The conservation of dry calcareous grasslands in the French Prealps strongly depends on the maintenance of low-intensity farming systems supported by agri-environmental schemes. An experimental assessment of the effect of current agro-pastoral management on the biodiversity of plant communities was conducted during a six-year permanent plot survey in four sites with contrasting habitat conditions (mesic to xeric). Analyses of species changes showed: (i) a strong increase in species richness and open grassland species frequencies four years after shrub-clearing, and (ii) a noticeable recovery of rare annuals and perennial species of conservation interest establishing in gaps created by grazing. At the community level, the restoration effect was evaluated by a between-year Correspondence Analysis, explaining 10.9% of the total floristic variability versus 29.5% for the site effect (between-site CA). Species ordination by between-year CA showed similar trajectories of vegetation changes during restoration despite different habitat conditions and grazing regimes between sites. The successful restoration of prealpine calcareous grasslands was explained by the availability of seed sources during the study in adjacent grazed or mown grasslands. Thus, restoration assessment should focus on dispersal possibilities and functional roles of species rather than species richness only. Finally, the spatial (i.e. the area of patches that need to be restored) and temporal (i.e. the frequency of shrub-clearing) implications for the large-scale conservation of prealpine calcareous grasslands by current agro-pastoral management are discussed.
TL;DR: There are significant correlations between landuse intensity, structural diversity and species richness at the habitat as well as on the landscape scale, which is mainly due to habitat and structural diversity, which increases with decreasing land-use intensity.
Abstract: This study is a quantitative approach to the estimation of bryophyte species richness in relation to land-use intensity at three spatial scales in highly cultivated areas A total of 460 randomly selected habitats and their various substrates within 29 study sites were investigated with regard to their land-use intensity and their bryophyte species richness in an agricultural region of eastern Austria On bare soils (substrate-scale), low but regular disturbance increases bryophyte diversity in comparison to lower land-use intensity However, more frequent disturbance (eg ploughing more than two times a year) dramatically reduces species richness at these sites, with more than 50% of these sites showing no bryophytes The production of reproductive units (sporophytes and vegetative units) is highest at an intermediate disturbance regime On the habitat, as well as on the landscape-scale, there is a significant increase in total bryophyte species number as well as in the number of threatened species with decreasing land-use intensity This is mainly due to habitat and structural diversity, which increases with decreasing land-use intensity There are significant correlations between landuse intensity, structural diversity and species richness at the habitat as well as on the landscape scale
TL;DR: Current knowledge of duiker ecology and niche separation is reviewed in order to assess likely indirect effects of Selective hunting or zoning on non-targeted species through changes in competitive dominance in different habitats.
Abstract: Duikers Cephalophus spp are an important source of food and income throughout the forest regions of Central and West Africa, and current levels of hunting are probably unsustainable, at least near large settlements The direct effects of hunting consist of two main aspects: overexploitation of target species, and incidental hunting of non-targeted or rare species because hunting is largely non-selective There are many methodological and practical problems to a technical approach to overexploitation, and there are increasing calls for alternative measures such as zoning and enforcement of exclusive local resource rights There is also increasing recognition of the need to ensure that hunting is more selective This paper reviews current knowledge of duiker ecology and niche separation in order to assess likely indirect effects of these measures on different species The main factor separating fundamental niches of sympatric species is body size, which limits dietary choice Additional descriptive factors include anatomical features – particularly the jaw musculature and size of mouth and neck; activity patterns and habitat preferences within closed canopy forest However, there is wide overlap of diets and broad tolerance of habitat disturbance by most species, and therefore niche overlap and interspecific competition may be high In the Upper Guinean forest in West Africa, but not in Central Africa, differential use of closed canopy forest and secondary vegetation also appears to be an important factor in niche separation; three pairs of species seem to be separated primarily by this factor Distributional variations in habitat use suggest that at least in the case of the yellow-backed duiker and the endangered Jentink's duiker, the separation is due to competition rather than to fundamental niche constraints Selective hunting or zoning will thus have indirect effects on non-targeted species through changes in competitive dominance in different habitats
TL;DR: The authors investigated epigaeic amphipod, carabid and ant distribution patterns across Afromontane forest/grassland ecotones and found little evidence to support the biological edge effect.
Abstract: The Afromontane region of South Africa is characterised by numerous small, remnant forests in a grassland matrix. The edges, or ecotones between forests and grasslands are usually sharp (typically just over a few metres) and are mainly maintained by both natural and, more recently, anthropogenic fires. We investigated epigaeic amphipod, carabid and ant distribution patterns across Afromontane forest/grassland ecotones and found little evidence to support the biological edge effect. Five of the fifty-two sampled species however, did increase significantly in abundance at the ecotone. Among these was a very distinct edge species, the amphipod Talistroides africana. Overall, carabids were more abundant and species rich in forests while for ants it was in the grasslands. Ants and carabids were both more abundant and species rich in spring and summer than in autumn and winter. More interestingly, the abundance and species richness patterns across the ecotone did not change with the passing of the seasons. We argue that a conservation strategy for the Afromontane forest patches must also incorporate the surrounding grassland. The grassland habitat is often perceived as less valuable than forest and, as a consequence, is subject to many anthropogenic disturbances such as fragmentation, cattle grazing and afforestation. Protecting grasslands around forest patches not only conserves the rich ant diversity, but also conserves the biota in the forests and at the edges, and would therefore be more meaningful in terms of the overall conservation of Afromontane biodiversity.
TL;DR: In this paper, the authors proposed to reduce livestock population and implement the ecodevelopment packages in order to ensure the corridor connectivity for the long-term conservation of the elephant population.
Abstract: Mudumalai Wildlife Sanctuary in southern India plays an important role in biodiversity conservation, especially of large mammals, by offering habitat contiguity of about 3300 km2 with three other protected areas in the region, namely Nagarahole and Bandipur National Parks and Wynaad Wildlife Sanctuary through forest corridors between the Western Ghats and Eastern Ghats forests. The habitat linkage is crucial for large ranging animals such as elephants, which use these forest corridors for migration. Livestock grazing, a major biotic interference in forest corridors, originates from seven settlements of the Masinagudi group of villages on the eastern and the southeastern fringes of the sanctuary. Construction of a series of hydroelectric power stations, numbering about three at Singara, Marvakandy (Masinagudi) and Moyar, around the Masinagudi villages caused a rapid growth in human population (143% between 1961 and 1991), particularly the landless labourers and livestock. Free grazing by about 15 000–17 000 resident as well as migratory livestock every year in and around the forest corridors, coupled with removal of cattle dung from the forest floor, have adversely affected the forest regeneration and helped proliferation of weed species such as Lantana camara, Casia tora, C. occidentalis, Opuntia dillenii, and Ageratum conyzoides. The annual fodder production from the corridor forest could meet the demand of about two-thirds of the resident population, while the crop residues from the marginal agriculture could not support the remaining one-third livestock population. In view of such a situation, measures have been suggested to reduce livestock population and implement the ecodevelopment packages in order to ensure the corridor connectivity for the long-term conservation of the elephant population.
TL;DR: In this paper, the role of riparian woodlands in the conservation of five common carnivore species as compared with other non-riparian habitats according to woodland cover on the landscape scale was investigated.
Abstract: This study analyses the role of riparian woodland in the conservation of five common carnivore species as compared with other non-riparian habitats according to woodland cover on the landscape scale (>60, 20–35 and <15% on 20 × 20-km surface area). I hypothesised that the importance of riparian woodlands in carnivore conservation on the regional scale would be greater in landscapes with low forest cover than in those with intermediate or high forest cover. To test this hypothesis, in each landscape type I sampled five riparian forests and 10–15 non-riparian habitats and recorded species richness and frequency of occurrence (number of sampled sites with species presence/total sampled sites) in both habitat types. The presence of (or use by) species at each particular sampling site was recorded using sign-surveys (search for scats and badger dens). The relative importance of riparian and non-riparian habitats in each landscape type was analysed by comparing species richness and frequency of occurrence for each species. Comparison of species richness and frequency of occurrence between landscape types indicate that riparian woodlands are important habitats in all landscape contexts. However, in accordance with the initial hypothesis, riparian woodlands are essential for carnivore conservation in the most deforested areas. Any agricultural or development policy should take into account the need to maintain and preserve riparian woodlands in landscapes, especially in intensively cultivated landscapes.