What can we infer about the behavior of extinct sirenians -- Sensory and morphological adaptation for an aquatic lifestyle -- Diving and foraging behaviors. Lucy Keith-Diagne, African Aquatic Conservation Fund -- Movement behaviors. Chip Deutsch, Associate Research Scientist, Florida Fish and Wildlife Conservation Commission -- Historical and current interactions with humans from the perspective of sirenian ethology and behavioral ecology -- Likely impacts of climate change on sirenian behavior -- Implications of sirenian behavior for conservation and management.
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Trapping was used to investigate small-mammal community composition of a cleared powerline corridor compared with that of surrounding tropical rainforest in the wet tropics of north-eastern Queensland and to determine whether movements from the rainforest across the corridor were inhibited. The dense exotic grassland of the cleared powerline corridor supported a small-mammal community composed mainly of the grassland species Melomys burtoni (73·3%) and Rattus sordidus (15·0%) with rainforest small mammals being restricted to woody-weed thickets along the rainforest–powerline corridor edge. The rainforest species Rattus sp. (80·3%), Melomys cervinipes (10·9%) and Uromys caudimaculatus (8·8%) comprised the small-mammal community of the forest interior. These rainforest species also inhabited rainforest edge habitat and regrowth rainforest connections across gullies. Movements of rainforest species across the grassland corridor were almost completely inhibited even under bait inducement, a result attributable to the substantial structural and microclimatic habitat differences within the clearing and to interspecific competition with the better-adapted species of the grassland community. Rainforest species used regrowth connections along gullies to cross the powerline corridor. Mitigation of the fragmentation effects caused by powerline grassy swathes can best be achieved by strengthening extant canopy connections in regrowth gullies, and by establishing new connections across the clearings.
Musky rat-kangaroos had a seasonal reproductive pattern. Males underwent a dramatic testicular expansion in October and the testes remained enlarged until April, when they reduced in size again. Females carried 1–3 pouch young from around March until October; juveniles were suckled until late December. Two primary food resources, fruits and litter fauna, underwent regular seasonal changes in abundance. The availability of fruits fluctuated to a greater degree than did that of litter fauna, both within and between years, which probably constituted the main selective pressure for a seasonal pattern of reproduction and high fecundity relative to most other macropodoids. Variation in the availability of fruits between years correlated with changes in the reproductive output of both male and female musky rat-kangaroos during breeding seasons.
Given recent concerns about the degradation of coral reef ecosystems world-wide, we investigated the environmental history of the Great Barrier Reef of Australia using qualitative methods. In particular, we used archival and oral history sources to reconstruct changes in coral reefs, islands and marine wildlife species for the period 1860—1970 and we evaluated the potential of qualitative methods to inform marine environmental research. Here, we argue that qualitative research offers a valuable means of reconstructing environmental changes, their drivers and their historical contexts. However, we found that qualitative methods also had important limitations. Hence we identify strategies for addressing those challenges and we suggest criteria for ensuring the accuracy and rigor of qualitative sources in marine environmental research. Overall, we argue that qualitative methods offer distinctive insights into the environmental history of the Great Barrier Reef, and that qualitative reconstructions can act as important triggers for conservation of marine ecosystems.
The historical exploitation of marine resources in Queensland has only been partially documented. In particular, the history of the commercial fishing of dugongs and marine turtles has received comparatively little scholarly attention. Since European settlement in Queensland, various human activities have exploited these resources. We present documentary and oral history evidence of the scale of those industries. Based on extensive archival and oral history research, we argue that diverse fishing practices occurred and that the sustained exploitation of dugongs, green turtles, and hawksbill turtles led to observable declines in the numbers of these animals – now species of conservation concern.
[Extract] The importance of northern Australia to the conservation of the world's biodiversity is increasingly important as other mega diverse areas become degraded. Much of northern Australia is under Indigenous tenure. Thus empowering Indigenous Australians, including Torres Strait Islanders, to make informed decisions about how to manage their natural resources is of local, national and international significance and accords with government policy.
Roads and powerline corridors destroy canopy connectivity in the rainforest of north-east Australia. We tested the hypotheses that linear barriers affect (a) the alignment of home ranges, (b) use of habitat either side of linear barriers, and (c) the crossing of them by the strictly arboreal lemuroid ringtail possum (Hemibelideus lemuroides), which is known to be vulnerable to habitat fragmentation. Radio-tracking and a translocation experiment were conducted at a narrow 7-m-wide road and an 80-m-wide powerline. Homes ranges of lemuroid ringtails ranged from 0.15 to 1.67 ha (minimum convex polygon) and were aligned with the road but not powerline corridors. When lemuroid ringtails were experimentally translocated, wider canopy clearings over roads reduced their capacity to return to their original home range, and the powerline corridor was a nearly insurmountable barrier. No possums were observed crossing roads or the powerline corridor at ground level or residing in the intervening matrix, indicating that loss of canopy connectivity has a negative impact on their movements.
Recent studies have estimated the historical abundance of large marine vertebrates to determine potential targets for conservation. We evaluated this approach using 1990s aerial survey estimates of dugong abundance and an estimate of the decline in dugong numbers since the 1960s based on changes in the catch per unit effort of dugong bycatch in a government shark control program on the east coast of Queensland, Australia. This analysis indicated that the catch rate of dugongs caught in shark nets, at six locations between latitudes 16.5° S and 28° S, declined at an average of 8.7% per year between 1962 and 1999. This represents a decline to 3.1% of initial catch rates over the sampling period. If the changes in the populations sampled by the shark nets and aerial surveys were equivalent, this result suggests that the region supported 72 000 dugongs in the early 1960s compared with an estimated 4220 dugongs in the mid-1990s. The seagrass habitat in the region is currently insufficient to support 72 000 dugongs, suggesting that our hindcast estimate may be an unrealistic target for recovery. Nonetheless, the evidence of serious dugong decline from the shark-net data and other sources has triggered significant conservation initiatives. This case study indicates that comparisons between historical and contemporary estimates of the abundance of large marine vertebrates can be powerful qualitative triggers for conservation action, but that quantitative targets for recovery require systematic testing of the assumptions underlying hindcast estimates, scientific evaluation of the current carrying capacity of the ecosystem for the target species, and consultation with a broad range of stakeholders. For some species, it may be more productive to set anthropogenic mortality targets that are designed to enable the population to recover to its optimum sustainable population than to set recovery targets per se.
Feeding free-ranging native animals is a form of wildlife-based tourism that is particularly popular in Australia as a result of the cryptic nature of many native species. The colony of Mareeba rock-wallabies (Petrogale mareeba) at 'Granite Gorge', North Queensland, where tourists feed a spatially defined subset of animals daily, was studied to determine the effects of provisioning on their behaviour and body condition. Provisioned P. mareeba had higher activity levels, including higher aggression levels, and spent more time performing contact behaviours (including mutual and non-mutual allogrooming) than did non-provisioned animals. Possible explanations for increased aggression include competition over provisioned food and territorial defence. Increased contact behaviours may serve to reduce tension caused by provisioning. The diurnal activities of the provisioned rock-wallabies were dictated by the activities of tourists. Provisioned rock-wallabies emerged from their shelters to receive food much earlier each afternoon than did the unprovisioned animals. The level of autogrooming exhibited by the provisioned wallabies was much higher than that of the unprovisioned animals, presumably as a thermoregulatory response to the high afternoon temperatures. Although provisioned P. mareeba feed more, their higher activity levels explain the lack of difference in the body condition between the two groups.
The elephant has deep cultural significance in Thailand and for the Thai people. The development of legal protection for Thai elephants reflects concerns about both human livelihoods and elephant conservation. Thus, the legal status of privately-owned domesticated, or captive Asian elephants, differs from that of wild Asian elephants, a situation that has consequences for the lawful use of ivory from domesticated animals. Prior to 2015, the lack of comprehensive measures to control the Thai ivory market enabled the laundering of illegally-sourced ivory through the country. The 2015 legal reforms of the Thai Government: 1) introduced strict controls over the possession and domestic trade of ivory from domesticated Asian elephants, and 2) aligned the protection of African elephants and their ivory with the CITES Convention. Nonetheless, the sustainability of the Thai ivory trade remains disputed, and international pressure to close the commercial trade in domestic ivory persists. This paper reviews this complex situation to inform future reforms. Consolidation of related laws would ease the enforcement tasks of officers and facilitate the compliance of stakeholders. Use of an electronic database would enhance the monitoring of ivory flow, as well as aid the implementation and enforcement of laws. This situation is a valuable example of the tensions between national and international attempts to conserve species important in wildlife trade.
