Mohammed Shobrak

Conservation status of gazelles in Saudi Arabia

Abstract The populations of the three gazelle species native to Saudi Arabia have been greatly reduced over the last fifty years. The Saudi gazelle Gazella (dorcas) saudiya is almost certainly extinct in the wild. Scattered populations of the mountain gazelle Gazella gazella still occur in the mountains of western Saudi Arabia and in the northern deserts. There is also one substantial population of the subspecies G. g. farasani on the Farasan Islands in the Red Sea. Sand gazelle Gazella subgutturosa marica are only found in two areas on the fringes of the Nafud desert in the north. As a result of the protected area system being established by the National Commission for Wildlife Conservation and Development, some populations of the two remaining species of gazelle can be expected to survive despite continued hunting pressure and overgrazing over much of the Kingdom, but their future is bleak outside protected areas.

Immune Indexes of Larks from Desert and Temperate Regions Show Weak Associations with Life History but Stronger Links to Environmental Variation in Microbial Abundance

Immune defense may vary as a result of trade-offs with other life-history traits or in parallel with variation in antigen levels in the environment. We studied lark species (Alaudidae) in the Arabian Desert and temperate Netherlands to test opposing predictions from these two hypotheses. Based on their slower pace of life, the trade-off hypothesis predicts relatively stronger immune defenses in desert larks compared with temperate larks. However, as predicted by the antigen exposure hypothesis, reduced microbial abundances in deserts should result in desert-living larks having relatively weaker immune defenses. We quantified host-independent and host-dependent microbial abundances of culturable microbes in ambient air and from the surfaces of birds. We measured components of immunity by quantifying concentrations of the acute-phase protein haptoglobin, natural antibody-mediated agglutination titers, complement-mediated lysis titers, and the microbicidal ability of whole blood. Desert-living larks were exposed to significantly lower concentrations of airborne microbes than temperate larks, and densities of some bird-associated microbes were also lower in desert species. Haptoglobin concentrations and lysis titers were also significantly lower in desert-living larks, but other immune indexes did not differ. Thus, contrary to the trade-off hypothesis, we found little evidence that a slow pace of life predicted increased immunological investment. In contrast, and in support of the antigen exposure hypothesis, associations between microbial exposure and some immune indexes were apparent. Measures of antigen exposure, including assessment of host-independent and host-dependent microbial assemblages, can provide novel insights into the mechanisms underlying immunological variation.

Species on the rocks: Systematics and biogeography of the rock-dwelling Ptyodactylus geckos (Squamata: Phyllodactylidae) in North Africa and Arabia

The understanding of the diversity of species in the Palearctic and the processes that have generated it is still weak for large parts of the arid areas of North Africa and Arabia. Reptiles are among their most remarkable representatives, with numerous groups well adapted to the diverse environments. The Ptyodactylus geckos are a strictly rock-dwelling genus with homogeneous morphology distributed across mountain formations and rocky plateaus from the western African ranges in Mauritania and the Maghreb to the eastern tip of the Arabian Peninsula, with an isolated species in southern Pakistan. Here, we use a broad sampling of 378 specimens, two mitochondrial (12S and cytb) and four nuclear (c-mos, MC1R, ACM4, RAG2) markers in order to obtain the first time-calibrated molecular phylogeny of the genus and place its diversification in a temporal framework. The results reveal high levels of intraspecific variability, indicative of undescribed diversity, and they do not support the monophyly of one species (P. ragazzii). Ptyodactylus species are allopatric across most of their range, which may relate to their high preference for the same type of structural habitat. The onset of their diversification is estimated to have occurred in the Late Oligocene, while that of several deep clades in the phylogeny took place during the Late Miocene, a period when an increase in aridification in North Africa and Arabia initiated.

Activity re-assignment and microclimate selection of free-living Arabian oryx: responses that could minimise the effects of climate change on homeostasis?

Predicting whether behaviour could buffer the effects of climate change on long-lived mammals requires a better understanding of the long-term behavioural responses of mammals to environmental stress. Using biologging, we measured locomotor activity and microclimate selection, over eight months, in five Arabian oryx (Oryx leucoryx) living free in a Saudi Arabian desert. The oryx displayed seasonal flexibility in activity patterns, shifting from a continuous 24-h activity pattern with crepuscular peaks in cooler months to a predominantly nocturnal activity pattern during the hottest months, without reducing the total 24-h activity level. The proportion of total 24-h activity that occurred during daylight hours was just 29±8% during the hottest months, versus 53±8% (mean±SD, n=5 oryx) in the other months. The attenuation in diurnal activity levels during the hot months was accompanied by the selection of cooler microclimates, presumably via shade seeking, during the heat of the day. Analysis of miniature black globe (miniglobe) temperature from a remote sensor on the collar of two female animals revealed that oryx selected microclimates cooler than the microclimates in direct sun at higher environmental heat loads across all periods, but with enhanced efficiency during the dry periods. We have quantified activity re-assignment and microclimate selection as responses to hot arid conditions in a free-living artiodactyl. Such flexible behavioural processes may act to buffer the adverse effects of the progressively hotter and drier conditions predicted to occur with climate change.

A comparison of derived population estimate, mark-resighting and distance sampling methods to determine the population size of a desert ungulate, the Arabian oryx

Post-release monitoring, including abundance cision, interdependence of consecutive estimates, and the assumption that all gains and losses are recorded, estimation, is an important part of reintroductions, providing a basis for management intervention designed to make DPE of limited value. At current densities, distance sampling along 455 km of driven transects yields too few achieve long-term persistence. The Arabian oryx Oryx leucoryx became extinct in the wild in 1972, surviving detections to derive precise estimates of N. To achieve a coeBcient of variation of 20% it would be necessary to as captive populations. Since 1982 reintroductions of Arabian oryx have taken place in Oman and Saudi Arabia. drive up to c. 2,900 km of transect; this amount of survey eCort could be achieved through pooling of data across Modelling of oryx population dynamics has highlighted the importance of precise estimation of population size repeat surveys of established transects. MR estimates, based on re-sighting of collared oryx, have the potential (N). Between 1990 and 2000 three methods of estimating N have been applied in Mahazat as-Sayd protected area to yield the most precise estimates of N when the proportion of marked animals reaches 30% of the total in Saudi Arabia: derived population estimates (DPE) based on known births and deaths, distance sampling, and population. The most reliable MR estimates available indicate the Mahazat as-Sayd Arabian oryx population mark-resighting (MR). This study assesses the feasibility and precision of these methods. Inability to assess prehad grown to >400 animals by 2000. (Stanley Price, 1989) and Saudi Arabia (Ostrowski et al., Introduction 1998). Although it is a white, relatively large ungulate, occupying open landscapes, the Arabian oryx roams The IUCN guidelines for reintroductions (IUCN, 1998) emphasize the importance of post-release monitoring. at low densities over vast areas and thus accurate estimation of population size is diBcult. In the Jiddat Such monitoring is essential in order to assess both the current status and the degree of management interal-Harasis region of Oman, site of the first reintroduction of Arabian oryx in 1982, the free-ranging population vention necessary to achieve long-term persistence of a re-established population (Seddon, 1999). A key objective was assessed until 1993 through regular monitoring of all individuals (A. Spalton, pers. comm.). Regular and for post-release monitoring is to determine the abundance of the target species, either as an index of relative frequent monitoring of oryx movements and demography provide a basis for assessing population size when the abundance, or an estimate of absolute density (Krebs, 1999). population is relatively small and all animals can be accounted for. However, as a population increases in The Arabian oryx Oryx leucoryx was extirpated from central Saudi Arabia in the early 1900s (Carruthers, size, precise assessment becomes more diBcult. Derived estimates, based on known births and deaths, may lack 1935) and was hunted to extinction in the wild by 1972 (Henderson, 1974). This left only captive populations the precision and thus the power to detect population trends. From 1990, when the Omani population numbered as founders for reintroduction programmes in Oman c. 100 animals, attempts were made to estimate total population size using the mark-resighting technique, Philip J. Seddon (Corresponding author) Department of Zoology, and this method was used exclusively from 1993 when University of Otago, P.O. Box 56, Dunedin, New Zealand. E-mail philip.seddon@stonebow.otago.ac.nz absolute counts were no longer possible (A. Spalton, unpub. data). At its peak in 1996 the Omani Arabian Khairy Ismail, Mohammed Shobrak and Stephane Ostrowski National Commission for Wildlife Conservation and Development, National Wildlife oryx population was estimated to number c. 400 freeResearch Center, P.O. Box 1086, Taif, Saudi Arabia. ranging animals, using over 16,000 km2 of the Arabian Oryx Sanctuary (Spalton et al., 1999). Chris Magin Fauna & Flora International, Great Eastern House, Tenison Road, Cambridge CB1 2TT, UK. Between 1990 and 1994 a total of 72 Arabian oryx were released into the Mahazat as-Sayd protected area Received 13 June 2002. Revision requested 25 September 2002. Accepted 20 May 2003. in western central Saudi Arabia (Fig. 1). Individuals came 286

Local Environment but Not Genetic Differentiation Influences Biparental Care in Ten Plover Populations

Social behaviours are highly variable between species, populations and individuals. However, it is contentious whether behavioural variations are primarily moulded by the environment, caused by genetic differences, or a combination of both. Here we establish that biparental care, a complex social behaviour that involves rearing of young by both parents, differs between closely related populations, and then test two potential sources of variation in parental behaviour between populations: ambient environment and genetic differentiation. We use 2904 hours behavioural data from 10 geographically distinct Kentish (Charadrius alexandrinus) and snowy plover (C. nivosus) populations in America, Europe, the Middle East and North Africa to test these two sources of behavioural variation. We show that local ambient temperature has a significant influence on parental care: with extreme heat (above 40°C) total incubation (i.e. % of time the male or female incubated the nest) increased, and female share (% female share of incubation) decreased. By contrast, neither genetic differences between populations, nor geographic distances predicted total incubation or females share of incubation. These results suggest that the local environment has a stronger influence on a social behaviour than genetic differentiation, at least between populations of closely related species.

Selective brain cooling in Arabian oryx (Oryx leucoryx): a physiological mechanism for coping with aridity?

SUMMARY Selective brain cooling is a thermoregulatory effector proposed to conserve body water and, as such, may help artiodactyls cope with aridity. We measured brain and carotid blood temperature, using implanted data loggers, in five Arabian oryx (Oryx leucoryx) in the desert of Saudi Arabia. On average, brain temperature was 0.24±0.05°C lower than carotid blood temperature for four oryx in April. Selective brain cooling was enhanced in our Arabian oryx compared with another species from the same genus (gemsbok Oryx gazella gazella) exposed to similar ambient temperatures but less aridity. Arabian oryx displayed a lower threshold (37.8±0.1°C vs 39.8±0.4°C), a higher frequency (87±6% vs 15±15%) and a higher maximum magnitude (1.2±0.2°C vs 0.5±0.3°C) of selective brain cooling than did gemsbok. The dominant male oryx displayed less selective brain cooling than did any of the other oryx, but selective brain cooling was enhanced in this oryx as conditions became hotter and drier. Enhanced selective brain cooling in Arabian oryx supports the hypothesis that selective brain cooling would bestow survival advantages for artiodactyl species inhabiting hot hyper-arid environments.

Parental cooperation in an extreme hot environment: Natural behaviour and experimental evidence

One of the most apparent examples of cooperation between unrelated individuals is biparental care whereby the male and the female parent share the rearing of the offspring. Theoretical models of care predict that selection should favour biparental care if it substantially improves the survival of the offspring. Although various ecological factors have been proposed to necessitate biparental care, experimental evidence is scant given the challenges of manipulating ecological factors in the natural habitat of animals. We carried out one such experiment in a small shorebird, the Kentish plover, Charadrius alexandrinus, that breeds in an extreme desert environment. Nest cover and thus exposure to solar radiation vary between nests, and we show that parents at exposed nests spent more time incubating than those at nests shaded by a bush (covered nests). Experimental removal and supplementation of nest cover gave results consistent with the observational data; at experimentally exposed nests both males and females increased incubation effort and relieved each other more frequently whereas at experimentally covered nests we observed the opposite. We conclude that exposure to extreme solar radiation influences biparental care and this necessitates parental cooperation in the Kentish plover. Furthermore, since parental care often coevolves with mating strategies, we conjecture that where the environment puts less pressure on the parents and provides the opportunity for reduced care, both mating systems and parental care can diversify over evolutionary time.

Role of wild birds as carriers of multi-drug resistant Escherichia coli and Escherichia vulneris

Emergence and distribution of multi-drug resistant (MDR) bacteria in environments pose a risk to human and animal health. A total of 82 isolates of Escherichia spp. were recovered from cloacal swabs of migrating and non-migrating wild birds. All bacterial isolates were identified and characterized morphologically and biochemically. 72% and 50% of isolates recovered from non-migrating and migrating birds, respectively, showed positive congo red dye binding (a virulence factor). Also, hemolysin production (a virulence factor) was showed in 8% of isolates recovered from non-migrating birds and 75% of isolates recovered from migrating birds. All isolates recovered from non-migrating birds were found resistant to Oxacillin while all isolates recovered from migrating birds demonstrated resistance to Oxacillin, Chloramphenicol, Oxytetracycline and Lincomycin. Some bacterial isolates recovered from non-migrating birds and migrating birds exhibited MDR phenotype. The MDR isolates were further characterized by API 20E and 16S rRNA as E. coli and E. vulneris. MDR Escherichia isolates contain ~1–5 plasmids of high-molecular weights. Accordingly, wild birds could create a potential threat to human and animal health by transmitting MDR bacteria to water streams and other environmental sources through their faecal residues, and to remote regions by migration.

Seasonal patterns in immune indices reflect microbial loads on birds but not microbes in the wider environment

Documenting patterns in immune function is a first step to understanding immune variation, but to comprehend causes and consequences, antigen and parasite exposure that may drive such variation must be determined. We measured host-independent microbial exposure in five species of larks (Alaudidae) in the Arabian Desert by sampling ambient air for culturable microbes during late spring and winter, two periods with contrasting environmental conditions. We developed a novel technique to assay densities of microbes shed from birds, and we quantified four indices of constitutive innate immunity. Birds shed significantly more microbes during spring than winter, and all immune indices except one were also significantly higher during spring. In contrast, concentrations of airborne environmental microbes were higher in winter. Among all birds in both seasons, lysis titers were positively correlated with total densities of microbes shed from birds, suggesting that immune defenses are directed towards the microbes that birds carry, rather than microbes in the wider environment. Our findings highlight the relevance of quantifying non-specific immune challenges in ecological immunology studies, and reinforce the importance of both host-dependent and host-independent measures of antigenic pressure for understanding immune variation.