Habitat Preference

We aimed to assess the impacts of recreational trampling on rare species, plant communities and landscape structure in the Iroise Biosphere Reserve (western France). Focusing on coastal grasslands, we first identified indicators discriminating human-induced short grasslands (i.e. maintained short by intensive trampling) from natural short grasslands (i.e. maintained by environmental constraints): the presence of lichens and succulent or woody species, which are known to be highly sensitive to trampling, as well as a shallow soil were good indicators of natural short grasslands. Recreational activities affected the majority of plots containing rare species, but one third of rare species (according to their habitat preference) appeared currently not threatened by recreational activities. The other rare species were found in grasslands with low trampling intensity and were not found in grasslands with greater trampling intensity. One lichen species (Teloshistes flavicans) was not affec...

The distribution and abundance of thirteen species of regular
sea urchin were assessed on Sosoikula and Nukubuco reefs, Fiji. Their
morphology and behavior were contrasted relative to wave activity,
water depth, substratum composition, food, and predation through all the
reefs zones. Densities and relative densities of species in each zone were
determined and their significance tested relative to the species distribution.
Results indicated species associations with different reef areas, thus
habitat preferences, which reflected species’ competitive abilities and
resource partitioning. Echinometra mathaei was the most prolific and
adaptable species, having the greatest densities in all zones. Peak mean
densities occurred in the mid back reef area on the echinoderm flat (2.64
ind. m–2), comprising 93.6% of all echinoids found. Diadema savignyi
and Diadema setosum were found at maximum densities in the boulder
zone, utilizing the narrow elevated crevice space. Both these species of
Diadema showed an increase in test diameters and spine lengths from
the reef crest to the hard coral bommies, proportional to the increase in
observed crevice size. Echinothrix diadema and Echinothrix calamaris
(brown color morph) demonstrated a similar trend, but with continued
growth-related migration to the Porites and soft coral zone. The white
color morph of E. calamaris showed no apparent association between
size distribution and crevice space. This was due to behavioral adaptations,
where both juveniles and adults aggregated together in the few
very large crevices found. Algal and seagrass species distributions
appeared to have only a moderate influence on echinoid species distributions,
as most species diets appeared broad within habitat. Predation
pressure was assessed to be relatively low, with greatest predator densities
on the fore reef (0.24 ind. m–2). Refuge quality and availability,
moderated by predation, combined with different echinoid morphologies
and behaviors, determined species distributions through the reefs varied
habitats.

The giant molerat Tachyoryctes macrocephalus is a high-altitude specialist endemic to the Bale Mountains, Ethiopia, and an important prey species for the endangered Ethiopian wolf Canis simensis. We assessed molerat prevalence, habitat preferences and availability to wolves, using direct observation and transect sampling for field signs. Mean densities of molerats ranged from 17/ha to 40/ha, and they were most prevalent

While climate change is expected to affect cetaceans primarily via loss of habitat and changes in prey availability, additional consequences may result from climate-driven shifts in human behaviors and economic activities. For example, increases in shipping, oil and gas exploration and fishing due to the loss of Arctic sea ice are highly likely to exacerbate acoustic disturbance, ship strikes, bycatch and prey depletion for Arctic cetaceans. In the tropics, climate change may result in increased hunting pressure on near-shore dolphins and whales off Asia, Latin America, Africa, and elsewhere as the availability of other marine resources diminishes. This study explores the range of potential consequences to cetaceans worldwide from predicted climate-driven shifts in human behavior, and evaluates the risks to particular species given their geographic ranges and habitat preferences. While concern about impacts of climate change on cetaceans has largely focused on polar species, the analysis presented here suggests tropical coastal and riverine cetaceans such as the Irawaddy dolphin, Indo-Pacific humpback dolphin, and finless porpoise are particularly vulnerable to those aspects of climate change that are mediated by changes in human behavior. Policy recommendations include the following: (1) information about cetacean populations should be incorporated into national, regional and international climate adaptation decisions wherever possible (for example, via GEF-sponsored adaptation initiatives); and (2) human-mediated impacts of climate change should be included in cetacean conservation and management plans, such as the management procedures of the International Whaling Commission (IWC), where possible. Because human responses to climate change are likely to evolve rapidly over the coming years and decades, it is important that local, regional and international cetacean conservation and management plans include regular reviews to allow them to adapt to new information.

The aim of the paper is the state-of-the-art assessment of the alien flora of Greece and its traits. The dataset consists of a total of 343 alien taxa, including 49 archaeophytes. The taxonomy, life traits and habitat of the 294 neophytes are analysed vs their naturalisation status. Out of the 122 (41%) naturalised neophytes, 50 are identified as exhibiting invasive behaviour. Poaceae, Asteraceae, Amaranthaceae, Solanaceae, Fabaceae, and Polygonaceae are the plant families richest in alien taxa. The majority of them are of American origin, followed by those of Asiatic and Mediterranean origin. The neophytes are predominantly herbs, most of them annuals. Yet, the perennial life cycle is equally frequent with the annual one and the proportion of phanerophytes in the alien flora is increased compared to the one of the native flora. Regarding flowering traits, most of the aliens have a long flowering period (over 1 month) and flower in late spring, summer and autumn, when few of the native plants are in bloom. Vertebrate zoochory and anemochory are the two dispersal modes mostly utilised by the alien plants (43 and 28%, respectively), while more than one dispersal mechanisms are functional for 56% of them. Artificial habitats have the highest frequencies of alien plants. The natural habitats with the highest numbers of aliens are the coastal ones and inland surface waters. Opuntia ficus-barbarica, Ailanthus altissima, Oxalis pes-caprae, Erigeron bonariensis, Amaranthus albus and Symphyotrichum squamatum are typical cases of plants characterised as invasive, having established in almost all the habitat groups identified. The diversity of the ecological characteristics of the plants suggests a potential of impacts that needs to be further assessed.

The Western Ghats (India) is a region of high biological diversity and endemicity of terrestrial fauna, but very little is known about its freshwater species distributions. Four rivers, Sharavati, Aghanashini, Bedti and Kali, of the central Western Ghats were studied for their fish diversity and composition. A total species richness of 92 species (and an endemicity of 25%) was reported. A comparison of expected species richness (SR) estimates using different statistical estimators was made – these showed the expected SR to be in the range of 92–120 species. Many of the species were found to be shared with those belonging to the southern Western Ghats, but the study also unearthed new findings in terms of description of a new species and extension of the known distribution range of some of the species. The study at varying spatial and temporal scales also showed that while the rivers are very similar to each other in terms of the SR values, they do vary with respect to the species composition. Species compositions across upper (or lower) reaches of these rivers were found to be more similar to one another than the upstream and downstream reaches in the same river. Temporal patterns, with regard to diurnal activity of fishes were studied. These showed that of the 72 species collected at night, 29 were exclusive to night sampling. Though much of the information of the feeding and habitat preferences of the fishes in this region is lacking, it is speculated that the differences in their activity patterns could be related to feeding and predator avoidance.

Canonical correspondence analysis (CCA) is a multivariate method to elucidate the relationships between biological assemblages of species and their environment. The method is designed to extract synthetic environmental gradients from ecological data-sets. The gradients are the basis for succinctly describing and visualizing the differential habitat preferences (niches) of taxavia an ordination diagram. Linear multivariate methods for relating two set of variables, such as two-block Partial Least Squares (PLS2), canonical correlation analysis and redundancy analysis, are less suited for this purpose because habitat preferences are often unimodal functions of habitat variables. After pointing out the key assumptions underlying CCA, the paper focuses on the interpretation of CCA ordination diagrams. Subsequently, some advanced uses, such as ranking environmental variables in importance and the statistical testing of effects are illustrated on a typical macroinvertebrate data-set. The paper closes with comparisons with correspondence analysis, discriminant analysis, PLS2 and co-inertia analysis. In an appendix a new method, named CCA-PLS, is proposed that combines the strong features of CCA and PLS2.