Nesting preferences of the green sea turtle (Chelonia mydas L.) and the hawksbill sea turtle (Eretmochelys imbricata L.) in the SW of Mahe Island in the Seychelles

Data concerning 212 turtles emerging on the southwest beaches of Mahe Island in the Seychelles were collected in 2017 and 2018. These data were used to model the probability of eggs being laid in relation to several variables. The probability of successful laying after emergence was highest on certain beaches and in areas of short vegetation, between open sand and trees. We found successful laying was related to the physical properties of the soil, indicating that survivability of embryos and hatchlings is higher in certain areas. The turtles appeared to choose zones where soil had low salinity, good drainage but ability to retain water, and absence of spring tides and extreme temperatures.

Nest-site selection by the white-tailed eagle and black stork – implications for conservation practice

Background Nesting trees and habitat represent the key factor underpinning stand selection by forest-dwelling birds. While two large European species – the black stork (Ciconia nigra L.) and white-tailed eagle (Haliaaetus albicilla L.) – are known to require old, large trees for nesting, we sought to investigate further by comparing species requirements at the levels of the nesting tree, nesting stand, and landscape. This entailed a detailed examination of forest features within circles of radius 15 m surrounding 16 and 19 trees holding the nests of storks and eagles respectively. The same parameters were also checked in the vicinity of 50 randomly-selected mature trees. Results Our results indicate different nesting preferences, with the eagles entirely confining themselves to Scots pine (Pinus sylvestris L.) – a species also chosen by black storks, which nevertheless regularly favour pedunculate oak (Quercus robur L.). Both species select trees of greater girth than the random ones, but white-tailed eagles choose to nest in the vicinity of patches of mature old stands with a loose canopy, to the extent that nesting trees and surrounding trees are of similar ages. In contrast, black storks prefer “veteran” trees with low-set crowns that are much older than any others in their vicinity. Nesting trees of the eagles are away from roads and close to lakes, while black storks do not avoid roads. Conclusions As the ages of nesting trees of both species are greater than ages at final cutting in this region’s managed forest, silvicultural measures will need to be adjusted, with small patches of forest spared, or larger areas as “islands” of old-growth. Likewise, as tending and thinning are engaged in, certain trees with horizontal branches will need to remain, with relict trees also left untouched. As it happens, all of these recommendations are anyway key elements of close-to nature silviculture and multifunctional forestry.

Nesting habitat of the broad-shelled turtle (Chelodina expansa)

Turtles have persisted for over 220 million years, despite facing threats at every life-history stage. In Australia, nest predation by introduced foxes has driven severe declines in some populations. Our project quantified the nesting habitat of the endangered broad-shelled turtle (Chelodina expansa) to facilitate protection of critical nesting grounds. We determined the nesting preferences of C. expansa at five distinct wetlands on the Murray River from 2011 to 2014. We identified environmental variables associated with nest sites in different habitats and compared those at nests and non-nest sites to determine nesting preferences. Kernel density estimates were used to identify important nesting grounds. Our study has important implications for conservation of C. expansa. Habitat preferences for nest sites of C. expansa are predictable both within and across sites, with females preferring to nest ~50 m from shore (~4 m elevation), in open habitat with little vegetation. Based on these habitat preferences, kernel density estimates showed that C. expansa may select the same nesting beaches in subsequent years. Fox depredation of nests (and nesting adults) drives turtle declines in Australia, so identifying nesting areas for protection is a first step in turtle conservation.

Spatiotemporal preferences in nesting of the hawksbill turtle (Eretmochelys imbricata) in Melaka, Malaysia

Nesting of hawksbill turtles (Eretmochelys imbricata) was monitored in 2013 and 2014 at 20 nesting beaches along the shores of Melaka, Peninsular Malaysia. Total nest numbers found were 481 and 463 in 2013 and 2014, respectively. The mean clutch size in 2013 of 123.5 ± 32.3 (SD) was similar to that in 2014 (118.5 ± 39.7). The distributions of nests were not uniform among the 20 beaches, and a large number of nests were found in Padang Kemunting, Kem Terendak, and Pulau Upeh, where the beaches were not always long. The nest sites indicated that the hawksbill turtle preferred to build its nest within the woody vegetation zone. The preferred vegetation species was Scaevola taccada. The temporal nesting pattern was year-round in both years, but the peak nesting season was between May and August, in the south-west monsoon season, possibly due to the gentle winds during this period. The turtles tended to nest between 22:01 and 24:00 h. This study provides basic information about hawksbill turtle nesting and insights into their spatial and temporal nesting preferences, which will contribute towards the conservation of this endangered species.

Contribution of DNA barcoding to the study of the bees (Hymenoptera: Apoidea) of Canada: progress to date

Bees (Hymenoptera: Apoidea, Apiformes) are taxonomically and ecologically diverse, with a wide range of social complexity, nesting preferences, floral associations, and biogeographic restrictions. A Canadian bee checklist, greatly assisted by the gene-assisted approach of DNA barcoding, is nearing completion. Previous evaluation of bee diversity in Canada, assisted by DNA barcoding, was restricted to Nova Scotia, which contains about 25% of the bee species in the country. Here, we summarise efforts to date to build a comprehensive DNA barcode library supporting bee taxonomic studies in Canada, consisting of more than 12 500 barcode-compliant sequences yielding 811 distinct barcode index numbers (BINs). This appears to represent ~95% of the 856 bee species presently recorded from Canada, but comparison with known morphological species in each genus shows that some genera are still under-sampled or may contain cryptic taxa, with much taxonomic work still to be done on bees in Canada. This is particularly true within the taxonomically difficult generaAndrenaFabricius (Andrenidae), HylaeusFabricius (Colletidae),MelissodesLatreille (Apidae),NomadaScopoli (Apidae),OsmiaPanzer (Megachilidae), andSphecodesLatreille (Halictidae). DNA analysis will likely be a key asset in resolving bee taxonomic issues in Canada in the future, and to date has even assisted studies of well-known bee taxa. Here we present summaries of our results, and discuss the use of DNA barcoding to assist future taxonomic work, faunal lists, and ecological studies.

Hylaeus communis (Hymenoptera: Colletidae), a new exotic bee for North America with generalist foraging and habitat preferences

We document a novel exotic bee for North America, Hylaeus (Hylaeus) communis Nylander, 1852 (Hymenoptera: Colletidae), and determine whether it is likely to spread widely across the continent. To evaluate the extent to which H. communis behaves as a generalist and would be able to adapt to novel North American environments, we compare the breadth of its climatic, floral, habitat, and nesting preferences between its native European range and sites where it was first discovered in southern Québec, Canada. Specifically, we calculate the paired difference index, which approximates species generalism, from a set of bipartite networks linking Hylaeus Fabricius, 1793 species to their respective floral hosts and habitats. Results indicate that H. communis is the most adaptable bee of the European Hylaeus fauna and will likely acclimate to its new environment, being a greater generalist than an already widely established exotic bee, H. hyalinatus Smith, 1842. In southern Québec, we find that, despite visiting a wide variety of flowering species, it exhibits a strong association with non-native plants and resides almost exclusively in urban settings. We hypothesise that H. communis will be able to spread widely throughout North America via multiple human-mediated but accidental dispersal events and by following the distribution of European weeds and horticultural plants.