Weak functional response to agricultural landscape homogenisation among plants,butterflies and birds

Measures of functional diversity are expected to predict community responses to land use and environmental change because, in contrast to taxonomic diversity, it is based on species traits rather than their identity. Here, we investigated the impact of landscape homogenisation on plants, butterflies and birds in terms of the proportion of arable field cover in southern Finland at local (0.25 km²) and regional (> 10 000 km²) scales using four functional diversity indices: functional richness, functional evenness, functional divergence and functional dispersion. No uniform response in functional diversity across taxa or scales was found. However, in all cases where we found a relationship between increasing arable field cover and any index of functional diversity, this relationship was negative. Butterfly functional richness decreased with increasing arable field cover, as did butterfly and bird functional evenness. For butterfly functional evenness, this was only evident in the most homogeneous regions. Butterfly and bird functional dispersion decreased in homogeneous regions regardless of the proportion of arable field cover locally. No effect of landscape heterogeneity on plant functional diversity was found at any spatial scale, but plant species richness decreased locally with increasing arable field cover. Overall, species richness responded more consistently to landscape homogenisation than did the functional diversity indices, with both positive and negative effects across species groups. Functional diversity indices are in theory valuable instruments for assessing effects of land use scenarios on ecosystem functioning. However, the applicability of empirical data requires deeper understanding of which traits reliably capture species’ vulnerability to environmental factors and of the ecological interpretation of the functional diversity indices. Our study provides novel insights into how the functional diversity of communities changes in response to agriculturally derived landscape homogenisation; however, the low explanatory power of the functional diversity indices hampers the ability to reliably anticipate impacts on ecosystem functioning.     

Climate change effects on animal ecology: butterflies and moths as a case study

Butterflies and moths (Lepidoptera) are one of the most studied, diverse, and widespread animal groups, making them an ideal model for climate change research. They are a particularly informative model for studying the effects of climate change on species ecology because they are ectotherms that thermoregulate with a suite of physiological, behavioural, and phenotypic traits. While some species have been negatively impacted by climatic disturbances, others have prospered, largely in accordance with their diversity in life-history traits. Here we take advantage of a large repertoire of studies on butterflies and moths to provide a review of the many ways in which climate change is impacting insects, animals, and ecosystems. By studying these climate-based impacts on ecological processes of Lepidoptera, we propose appropriate strategies for species conservation and habitat management broadly across animals.     

Contrasting patterns in species richness of birds,butterflies and plants along riparian corridors in an urban landscape

Aim Urbanization is a major driver of global land‐use change, substantially modifying patterns of biodiversity. Managing these impacts has become a conservation priority. The creation and maintenance of greenways, such as river corridors, is frequently promoted as a strategy for mitigating habitat fragmentation in urban areas by bringing semi‐natural habitat cover into city centres. However, there is little evidence to support this assertion. Here, we examine whether riparian zones maintain semi‐natural habitat cover in urban areas and how species richness varies along such zones. Location Sheffield, Northern England. Methods Multiple taxonomic groups (birds, butterflies, plants) were surveyed at 105 sites spanning seven riparian corridors that transect the study system. For all groups, we model the relationships between species richness and environmental variables pertinent to an urban system. To test whether riparian zones can act to maintain semi‐natural habitats within a city, we modelled the proportion of semi‐natural land cover within 250 m grid squares that do, and do not, contain a river. Results Species richness varied markedly in relation to distance from the urban core. Trends differed both between taxonomic groups and between rivers, reflecting the complex patterns of environmental variation associated with cities. This suggests that biodiversity surveys that focus on a single group or transect cannot reliably be used as surrogates even within the same city. Nonetheless, there were common environmental predictors of species richness. Plant, avian and butterfly richness all responded positively to Habitat Diversity and the latter two declined with increases in sealed surface. Main conclusions Multiple transects and taxonomic groups are required to describe species richness responses to urbanization as no single pattern is evident. Although riparian zones are an important component of the mosaic of urban habitats, we find that river corridors do not disproportionately support tree and Natural Surface Cover when compared to non‐riverine urban areas.     

The role of landscape texture in conservation biogeography: a case study on birds in south-eastern Australia

The binary classification of landscapes into suitable vs. unsuitable areas underlies several prominent theories in conservation biogeography. However, a binary classification is not always appropriate. The textural discontinuity hypothesis provides an alternative theoretical framework to examine the geographical distribution of species, and does not rely on a binary classification scheme. The texture of a given landscape is the combination of its vertical structural complexity and horizontal spatial grain. The textural discontinuity hypothesis states that biophysical features in the environment are scaled in a discontinuous way, and that discontinuities in the body size distribution of animals mirror these biophysical discontinuities. As a result of this relationship, a complex landscape texture should be associated with small‐bodied animals, whereas a simple landscape texture should be associated with larger‐bodied animals. We examined this hypothesis for birds in five landscapes in south‐eastern Australia that represented a gradient from simple to complex landscape texture. In landscapes with a complex texture, the number of detections of small birds was higher than expected, and the number of detections of larger‐bodied birds was lower than expected. The opposite pattern was found in landscapes with a simple texture. The pattern remained significant when only bird species found in each of the five landscapes were considered, which demonstrated that the association of landscape texture with body size was not an artefact of landscapes differing in their species pools. Understanding the effects of landscape texture on species distribution patterns may be a promising research frontier for conservation biogeography. We hypothesize that the active management of landscape texture may be used to attract or deter animals of certain body sizes. Consistent with other theories, the textural discontinuity hypothesis therefore suggests that managing entire landscapes, rather than only predefined patches, is an important conservation strategy.     

Evaluating butterflies as surrogates for birds and plants in semi-natural grassland buffers

Semi-natural grasslands can support diverse faunal and floral communities, including grassland birds, beneficial insects, and native wildflowers. Monitoring biodiversity of this type of ecosystem is important to assess abundance and richness of grassland-associated species, evaluate success of establishing grasslands, and to assess overall ecosystem health. We tested butterflies as surrogates for birds and plants to assess establishment success of semi-natural grassland buffers in north-central Mississippi using Spearman rank correlation (Spearman’s ρ). Disturbance and grassland butterfly guilds were generally not suitable surrogates for grassland bird metrics, non-grassland bird metrics, or nest density metrics. Butterflies did have consistent positive correlations with plant species richness and forb metrics, as well as consistent negative correlations with grass metrics, but these correlations were generally smaller than what is considered suitable to serve as surrogates. In general, butterflies were not suitable surrogates for birds or plants in semi-natural grassland buffers.     

Factors affecting the distribution of vascular plants, springtails, butterflies and birds on small tropical islands

Aim

The primary objective of our study was to examine the factors affecting the distribution of vascular plants, springtails, butterflies and birds on small tropical islands to understand how different groups of organisms with distinct biological traits respond to biogeographical variables, such as island area.

Location

The Republic of Singapore (103°50′E, 1°20′N) located at the southern tip of Peninsular Malaysia.

Methods

Seventeen islands were surveyed for vascular plants, springtails, butterflies and birds. Correlation analysis, simple linear and multiple regression analyses and the nestedness index were used to test the hypotheses that (1) area is the best predictor of species/genus richness at both the community and specific/generic levels; (2) there is no correlation between population density and island area; and (3) species/genera are distributed as nested subsets.

Results

Area was the most significant factor in determining the island distribution of springtails, butterflies and birds at both the community and specific/generic levels, although there were disparate responses to the biogeographical variables between the three taxonomic groups, as well as between common species within each group. Individual species displayed disparate responses to biogeographical variables, suggesting that patterns of distribution at the community level may not be a good indicator of the population dynamics of individual species/genera. Plant species richness did not show any correlation with any of the tested variables. Population densities of springtails, butterflies and birds were positively correlated with area, contradicting the assumption of the equilibrium theory of island biogeography that population density of island species is independent of area. Population densities of plants showed no correlation with any of the tested biogeographical variables. Vascular plant, springtail, butterfly and bird communities on the islands showed significant patterns of nestedness, indicating there may be species/genus‐specific responses to biogeographical variables.

Main conclusions

We conclude that although area was the most important factor affecting the island distribution of springtails, butterflies and birds, conservation planning must take into consideration how target taxonomic groups respond to biogeographical variables, instead of relying on general principles (e.g. those derived from the equilibrium theory). On a local scale, in order to preserve the island biodiversity of Singapore, the highest priority should be given to preserving the larger islands (e.g. Pulau Ubin) which not only have higher numbers of species, but also species that are absent on smaller islands.

     

Torpor in birds: taxonomy, energetics, and ecology

Recent reports on patterns and occurrence of torpor and other natural hypothermic states in birds have prompted a revision of many longstanding opinions. For instance, a larger assortment of birds covering a wider range of body mass than previously recognized uses energy-conserving mechanisms in the face of abundant food supplies. Thus, although acute energetic stress triggers the occurrence of hypometabolic states in many birds, energy deficits can no longer be regarded as the sole stimulus for avian torpor. Additionally, the phenology of this phenomenon (phases, duration, depth) shows more interspecific variation than previously appreciated, and traditional concepts of the phases of torpor are not always adequate. Hence, inclusive definitions of torpor based on physiological and/or behavioral criteria have become more difficult to formulate. However, average nighttime body temperature, which is highly consistent throughout the class Aves (38.54 degrees +/- 0.96 degrees C, n = 202), provides a convenient reference for detecting natural hypothermic states. Of the putative ecological factors associated with avian torpor, food specialization seems a prime candidate as an ultimate factor in the occurrence of this state in birds. With few exceptions, all of these animals capable of torpor are either frugivorous, nectarivorous, or insectivorous, suggesting a correlation between thermoregulatory pattern and predictability of food supply. To date, no clear answer exists as to whether the variety of thermoregulatory patterns evident in birds involves discrete mechanisms or merely steps in a physiological continuum. However, I suggest that the occurrence of differences in torpor patterns among closely related species (e.g., within families) favors the latter interpretation.     

Nestedness in fragmented landscapes: a case study on birds, arboreal marsupials and lizards

Aim The potential nestedness of assemblages of birds, arboreal marsupials and lizards was examined in a fragmented landscape in south‐eastern Australia. We assessed which ecological processes were related to the presence or absence of nestedness, particularly in relation to previous autoecological studies in the same study area. Location Data were collected at Buccleuch State Forest, c. 100 km to the west of the Australian Capital Territory in south‐eastern Australia. Methods Presence/absence matrices were compiled for birds (40 pine sites, 40 continuous forest sites, 43 fragments), arboreal marsupials (41 continuous forest sites, 39 fragments) and lizards (30 sites including all landscape elements) from a range of field surveys conducted since 1995. Nestedness was analysed using a standardized discrepancy measure, and statistical significance was assessed using the RANDNEST null model. For birds, species thought to be extinction‐prone were analysed separately to assess if assemblages comprising extinction‐prone species were more strongly nested than others. Also, sites with a substantial amount of Eucalyptus radiata were analysed separately to assess whether nestedness was stronger if environmental heterogeneity was minimized. Results The assemblages of lizards and arboreal marsupials were not nested, probably because of qualitative differences between species in response to environmental conditions. The assemblages of birds in fragments and pine sites were significantly nested, but nestedness was substantially stronger in fragments. For birds, nestedness appeared to be related to somewhat predictable extinction sequences, although there were many outliers in the analysis. Nestedness increased when extinction‐prone species were analysed by themselves. Nestedness decreased when environmental heterogeneity was minimized by including only sites dominated by E. radiata. Main conclusions In a given landscape, different vertebrate assemblages can respond in vastly different ways to fragmentation. Nestedness analyses can provide a useful overview of likely conservation issues in fragmented landscapes, for example by highlighting the possible roles of local extinction and immigration. However, nestedness analyses are a community‐level tool, and should be complemented by more detailed autoecological studies when applied in a conservation context.     

Two approaches to zoogeography: a study based on the distributions of butterflies, birds and bats in the Indo -Australian area

In this paper the recorded distributions of butterfly, bird and bat taxa in the Indo-Australian area are subjected to various kinds of numerical analysis. Numerical methods are used to assign primary areas to zoogeographic regions and to assign taxa to faunal elements. An attempt is made to relate these classifications to the past geographical history of the area, and hence to infer something about past trends of spread and speciation in each group.     

Integrating ecology with biogeography using landscape characteristics: a case study of subtidal habitat across continental Australia

Aim We aimed to redress a current limitation of local ecological studies (i.e. piecemeal information on specific taxa) by integrating existing ecological knowledge with quantifiable patterns in primary habitat (i.e. composition, distribution and cover) from local to continental scales. By achieving this aim, we sought to provide a biogeographical framework for the interpretation of variation in the ecology of, and threats to, subtidal rocky landscapes. Location The subtidal rocky coast of continental Australia, with longitudinal comparisons spanning > 4000 km of southern coast (115°03′ E–153°60′ E) between latitudes of 33°05′ S and 35°36′ S, and latitudinal comparisons across 26°40′ S to 37°08′ S of eastern Australia. Methods The frequency and size of patches of major benthic habitat were quantified to indicate contemporary function (ecology) and to establish patterns that may result from contrasting regional‐scale processes (biogeography). This was achieved by quantifying the composition and patchiness of key subtidal habitats across the continent and relating them to the known ecology of subsets of locations in each region. A nested design of several spatial scales (1000s, 100s, 10–1 km) was adopted to distinguish patterns at local through to biogeographical scales. Results We show biogeography (in terms of longitude and latitude) to have a fundamental influence on the patterns of abundance and composition of subtidal habitats across regional (1000s of kilometres) to local (10s of kilometres to metres) scales. Across the continent, the most fundamental patterns related to (1) the proportion of rock covered by kelp forests, as related to particular functional groups of herbivores, and (2) the small‐scale heterogeneity (metres) that characterizes these forests. Main conclusions We interpret these results within a framework of alternative processes known to maintain habitat heterogeneity across these regions (e.g. productivity versus consumption as shapers of habitat structure). These interpretations illustrate how regional differences in ecological patterns and processes can create contradictory outcomes for the management of natural resources. We suggest that researchers and managers of natural resources alike may benefit from understanding local issues (e.g. the effects of fishing and its synergies with water pollution) in their biogeographical contexts.     

On the surrogate value of red-listed butterflies for butterflies and grasshoppers: a case study in Grammos site of Natura 2000, Greece

We tested the surrogate value of butterflies, red-listed butterflies and grasshoppers for each other in terms of diversity patterns congruence and complementarity at a site in the NATURA 2000 network. Grammos Mountain is proposed as a new Prime Butterfly Area for Greece: it supports a total of 56 grasshopper species and 112 butterfly species, 24 of which are of European conservation concern (SPEC) and two of Prime Butterflies Area Project. We found a strong congruence in the species richness patterns of SPEC butterflies, butterflies and grasshoppers, because three common ecological factors influenced them: number of flower heads, altitude, and cover of low trees or bushes (Redundancy Analysis, CANOCO). Each complementarity network maintained quite well the species richness of the other two target groups (<18% average species loss). SPEC butterflies were the best surrogate group overall and therefore we propose that they should be monitored on a permanent basis.     

基于景观生态的城市土地开发适宜性评价——以丹东市为例

城市土地开发适宜性评价是城市总体规划中的一项重要基础性工作,其核心是合理分配利用有限的土地资源。在进行耕地适宜性评价和建设用地适宜性评价的基础上,针对丹东市不同的发展目标,提出3个城市土地开发适宜性评价方案,包括经济发展优先方案、生态保护优先方案以及协调发展方案,并按照3个方案对丹东市进行城市土地开发适宜性评价。通过选择适当指标,构建了由景观稳定度和景观干扰度组成的景观生态质量评价体系,并对3个适宜性方案进行对比与优选。结果表明,丹东市按照经济发展优先的城市土地开发适宜性方案进行开发,则景观干扰程度最高,景观稳定程度最低,景观生态质量最低;按照生态保护优先方案进行开发,则景观干扰程度居中,景观稳定程度最高,而景观生态质量居中;按照协调发展方案进行开发,则景观干扰程度最低,景观稳定程度居中,并且具有最高的景观生态质量。通过综合比较,应选择协调发展方案作为丹东市城市建设空间布局的首选方案。     

中性景观模型在景观生态学中的应用和发展

中性景观模型可以模拟产生大量具有相似统计特征而不包含特定生态过程或自然地理过程的格局,为研究真实景观提供一个参照系统,在大范围景观格局变化研究等方面提供便利.目前,中性景观模型成为景观生态学研究的一种重要方法和手段,已成功应用于检验现有景观指数并发展新的景观指数、景观格局对种群动态影响和干扰过程研究等多个领域.本文介绍了中性景观模型的产生、内涵和类型,阐述了中性景观模型在景观生态学中的应用.同时,展望了中型景观模型研究的发展方向:模型类型趋于多样化,结构趋于复杂化,着重模型模拟结果的验证,以及随着景观生态学理论和实践的发展、结合中性景观模型和景观生态学研究方法,深入地应用于格局和过程两者之间关系的研究.     

基于景观生态学“源-汇”理论的市域尺度生态功能分区——以内蒙古通辽市为例

市域尺度的生态功能分区对于市域生态资源的有效保护和合理利用起着不可替代的指导作用。现阶段较为被动而静态的功能分区研究忽视了市域生态资源在城镇化发展中的剧烈变化。而景观生态学的"源-汇"概念和相关手段,将区域生态功能空间格局与不断变化的生态过程之间建立了联系,在生态功能分区科学理性的研究实践中运用前景广阔。运用景观生态学"源-汇"理论,以内蒙古通辽市为例,通过对于研究区域中"源"景观的划分,设定不同景观要素的阻力值,构建基于"源"动态特征的最小累计阻力模型,计算得出阻力面。并进一步通过寻找阻力面突变点来确定分区阈值,最终确定通辽市域尺度生态功能的5大分区,最后提出有针对性的分区管控措施与指引。研究将市域生态要素在城市化下的动态演变与生态安全格局进行有机关联并制定科学的分区策略,为市域生态空间的优化及管理提供了理论依据。     

Species invasions exceed extinctions on islands worldwide: a comparative study of plants and birds

Species richness is decreasing at a global scale. At subglobal scales, that is, within any defined area less extensive than the globe, species richness will increase when the number of nonnative species becoming naturalized is greater than the number of native species becoming extinct. Determining whether this has occurred is usually difficult because detailed records of species extinctions and naturalizations are rare; these records often exist, however, for oceanic islands. Here we show that species richness on oceanic islands has remained relatively unchanged for land birds, with the number of naturalizations being roughly equal to the number of extinctions, and has increased dramatically for vascular plants, with the number of naturalizations greatly exceeding the number of extinctions. In fact, for plants, the net number of species on islands has approximately doubled. We show further that these patterns are robust to differences in the history of human occupation of these islands and to the possibility of undocumented species extinctions. These results suggest that species richness may be increasing at subglobal scales for many groups and that future research should address what consequences this may have on ecological processes.     

Active and resting metabolism in birds: allometry, phylogeny and ecology

Variation in resting metabolic rate is strongly correlated with differences in body weight among birds. The lowest taxonomic level at which most of the variance in resting metabolic rate and body weight is evident for the sample is among families within orders. The allometric exponent across family points is 0.67. This exponent accords with the surface area interpretation of metabolic scaling based on considerations of heat loss. Deviations of family points from this allometric line are used to examine how resting metabolic rates differ among taxa, and whether variation in resting metabolic rate is correlated with broad differences in ecology and behaviour. Despite the strong correlation between resting metabolic rate and body weight, there is evidence for adaptive departures from the allometric line, and possible selective forces are discussed.
The allometric scaling of active metabolic rate is compared with that of resting metabolic rate. The allometric exponents for the two levels of energy expenditure differ, demonstrating that active small-bodied birds require proportionately more energy per unit time above resting levels than do active large-bodied birds. No consistent evidence was found to indicate that the different methods used to estimate active metabolic rate result in systematic bias. Birds require more energy relative to body size when undertaking breeding activities than at other stages of the annual cycle.     

景感生态学在城市生态系统服务中的应用研究——以城市公园景观设计为例

城市生态系统服务和可持续发展是当前城市生态学研究的热点问题。景感生态学作为联系生态系统服务和可持续发展的桥梁,可作为研究城市生态系服务和可持续发展的一种有效途径。随着社会发展所伴随的人们经济生活的生活压力增大,城市居民的亚健康状态日益突出。城市公园作为城市生态系统的重要构成,其设计目的应考虑应对城市居民健康问题和促进人类精神文明建设方面的作用。以城市公园景观设计为例,从园路、建筑、植物、水体景观和小品等方面探讨景感生态学在城市公园景观设计中的应用价值。景感生态学作为探索城市公园景观设计的新思路,以实现生态效益和居民福祉的提升,丰富和提升城市公园的生态系统服务功能,从而有利于促进为人类当代和后代提供可持续的福祉,以期驱使人类行为和言行规律朝着对生态系统有益的方向演化,自觉维护和改善生态系统服务,从而可持续地保障城市生态系统服务。