试论“三北”生态经济型防护林体系

本文介绍了“三北”防护林体系工程的概要、建设指导思想和技术路线,从理论上较深入地探讨了林业观念更新的意义及其基础。从而,提出“生态经济型防护林体系”的学术概念,以及它同建立区域性人工生态系统的相互关系,并结合“三北”黄土高原昕水河流域生态经济型防护林体系示范区的特点进行分析,探讨丘陵山地条件下,生态经济型防护林体系的技术内涵、组成及其生态经济特点。最后,作者提出了由“三北”防护林工程的实践对我国如何建设好其它防护林工程的几点启示。     

Thermal ecology of natterjack toads (Bufo calamita) in a semiarid landscape

(1).

To monitor the seasonal variation of body temperature (t_b) in free-ranging adult Bufo calamita, 15 toads were radio-tracked at Mas de Melons (Catalonia, Spain) using temperature-sensitive transmitters implanted to the abdominal cavity.     

A note on the effectiveness of behavioural rehabilitation for reducing inter-dog aggression in shelter dogs

The effectiveness of a rehabilitation program for reducing inter-dog aggression was evaluated at the municipal animal shelter. Sixteen dogs (of 60 examined) met the study criteria of medium inter-dog aggression as determined by an inter-dog aggression test. These dogs received a 10-day treatment of daily rehabilitation for 30 min (rehabilitation group, n = 9) or daily release into an outdoor enclosure for 30 min (control group, n = 7). Rehabilitation consisted of desensitising and counter-conditioning dogs to the approach of other “stimulus” dogs. Most dogs in the rehabilitation group showed a decline in aggression scores when re-tested after the last treatment (day 11), and differed significantly from the control dogs which showed either an increase or no change in aggression scores (U = 8.5, P < 0.01). Rehabilitation dogs also showed lower frequencies of aggressive body postures (“facing the stimulus dog”, P < 0.05, and “stiff posture”, P < 0.10) and higher frequencies of less assertive postures (“ears back”, P < 0.05, and “lowered neck”, P < 0.10) on day 11. The differences between groups were no longer significant when a reduced sample of dogs was tested 1 week after rehabilitation ended (day 18). The study shows short-term reduction of inter-dog aggression through rehabilitation, but further work is needed on effective ways of maintaining the behavioural change.     

Nurse effect of Bolax gummifera cushion plants in the alpine vegetation of the Chilean Patagonian Andes

Abstract. It has been proposed that in the harsh arctic and alpine climate zones, small microtopographic variations that can generate more benign conditions than in the surrounding environment could be perceived as safe sites for seedling recruitment. Cushion plants can modify wind pattern, temperature and water availability. Such modifications imply that cushion plants could act as ‘nurse plants’ facilitating the recruitment of other species in the community. This effect should be more evident under stressful conditions. We tested these hypotheses comparing the number of species that grow inside and outside Bolax gummifera cushions at two elevations (700 and 900 m a.s.l.) in the Patagonian Andes of Chile (50°S). At both elevations, and in equivalent areas, the number of species was registered within and outside cushions. A total of 36 and 27 plant species were recorded either within or outside B. gummifera cushions at 700 and 900 m a.s.l., respectively. At 700 m a.s.l., 33 species were recorded growing within cushions and 29 outside them, while at 900 m a.s.l. these numbers were 24 and 13 respectively. At both elevations there were significantly more species growing within than outside cushions, and the proportion of species growing within cushions increased with elevation. Thus there is a nurse effect of cushion plants and it is more evident at higher elevations. Shelter from wind and increased soil water availability seem to be the factors that increase plant recruitment within cushions.     

Human skeletal remains from Mumba Rock Shelter,Northern Tanzania

During their expeditions in Northern Tanzania in 1934/38, Ludwig and Margit Kohl-Larsen (discoverer of Eyasi and Garusi hominids)excavated i. a. the Mumba Rock Shelter. This important excavation yielded human skeletal remains of 18 individuals. The most relevant results of the morphological analyses are presented here. According to the affinities and absolute dating (hominid IX, 3700 B. C. ), the present study supports recent indications of the presence of Negroid groups in East Africa at an early stage in Later Stone Age times.     

Thorn fish Terapon jarbua (Forskål) predation on juvenile white shrimp Penaeus indicus H. Milne Edwards and brown shrimp Metapenaeus monoceros (Fabricius): the effect of turbidity, prey density, substrate type and pneumatophore density

A series of laboratory experiments was conducted at Inhaca Island Marine Biological Station, Mozambique, in order to assess the separate effects of turbidity, prey density, substrate type, pneumatophore density, and the combined effects of turbidity with the latter three, on rate of predation by the thorn fish Terapon jarbua (Forskål, 1775) on white shrimp Penaeus indicus and brown shrimp Metapenaeus monoceros.Significant interactions between turbidity and the other three factors on shrimp predation for both prey species were detected. Regardless of prey density, increasing turbidity decreased predation on P. indicus, but not on M. monoceros, for which increasing densities reduced the protective effect of turbidity. Increasing prey density increased predation on P. indicus in clear water, and increased predation on M. monoceros in low and high, but not in intermediate turbidity or clear water. The presence of a substrate suitable for burying decreased predation on M. monoceros in clear water, but not in the turbidity levels used. In clear water, solely sandy-shell substrate afforded protection to P. indicus, while in turbid water, no substrate offered significant protection and muddy substrate even increased prey vulnerability to fish probably as a result of increased preys' locomotor activity. Raising pneumatophores density seems to lower the protective value of turbidity for both species. In clear water, only low and high structure density provided a deterrent effect on predation on P. indicus; in turbid water, intermediate and higher structure density increased predation. Increasing structural complexity reduced predation on M. monoceros linearly in clear water; but in low turbid water it increased. In high turbid waters, the increase was only significant in intermediate pneumatophore density. High structural complexities impair the pursuing capacity of fish and thus decreased predation rates. The results indicate that the effective provision of shelter of different habitats depends not only on the various environmental parameters analysed, but also on the way they interact and on the behaviour of prey and predator as well.     

Is microclimate important for Orthoptera in open landscapes?

Orthoptera were monitored on field edge public footpaths on the east (leeward) and west (windward) side of hedgerows in Chelmsford, UK, in 2006. A total of 6 species were recorded from footpaths on the leeward side of hedgerows probably due to the shelter from the prevailing westerly winds provided by the trees and shrubs. On the windward side of hedgerows species richness and abundance of Orthoptera were reduced (only 4 species were recorded). It is suggested that shelter from the wind and the exposure to early morning sunlight for Orthoptera on the east side of hedgerows are important factors governing their occurrence on farmland. Many replicates had Environmental Stewardship (ES) scheme field margins adjacent but they did not affect Orthoptera species richness or abundance.     

Does thermoregulatory behaviour of green toads (Bufo viridis) constrain geographical range in the west? A comparison with the performance of syntopic natterjacks (Bufo calamita)

(1)

Behavioural regulation of body temperature (t_b) was monitored in 23 free-ranging Bufo calamita (Bc) and 17 syntopic Bufo viridis (Bv) at Urmitz (Rhineland-Palatinate, Germany) using temperature-sensitive transmitters implanted to the abdominal cavity.

(2)

In field t_b varied between +0.5 and 37.4 °C in Bc and between +0.6 and 33.7 °C in Bv. Maximum t_b of a Bc measured during an experimental trial was 38.8 °C.

(3)

Natterjack toads avoided environmental temperature extremes by burrowing actively into moist sandy soil (2-90 cm deep), whereas green toads hid exclusively in mammal burrows or pre-existing subterranean cavities. Shelter choice did not vary between summer and winter.

(4)

Average t_b of Bc exceeded significantly that of Bv during summer (26.7 °C vs. 24.7 °C), while the reverse was true during winter (4.2 °C vs. 7.2 °C). Following hibernation the body condition of Bv was significantly lower than that of Bc.

(5)

We conclude that green toads fail to colonise regions west of the Rhine valley because of a combination of winter temperatures impeding foraging trips for prolonged periods, the choice of warm hibernacula increasing metabolic costs and/or predation risk and reduced fecundity.

     

试论“三北”生态经济型防护林体系

本文介绍了“三北”防护林体系工程的概要、建设指导思想和技术路线,从理论上较深入地探讨了林业观念更新的意义及其基础。从而,提出“生态经济型防护林体系”的学术概念,以及它同建立区域性人工生态系统的相互关系,并结合“三北”黄土高原昕水河流域生态经济型防护林体系示范区的特点进行分析,探讨丘陵山地条件下,生态经济型防护林体系的技术内涵、组成及其生态经济特点。最后,作者提出了由“三北”防护林工程的实践对我国如何建设好其它防护林工程的几点启示。     

The influence of habitat and behavioural interactions on the local distribution of the wrasse,Pseudolabrus celidotus

Synopsis The temperate wrasse, Pseudolabrus celidotus (Labridae), was studied in a shallow rocky reef habitat to asses how ecological and behavioural factors influence its within habitat patterns of distribution. Emphasis was placed on examining the mechanisms underlying size/age related changes in dispersion and habitat use. Juveniles (< 100 mm SL) were found to be aggregated whereas adults tended to be more randomly dispersed. This pattern appeared to be a product of both (a) ecological, and (b) behavioural factors. (a) Juveniles were closely associated with shelter (macro-algae) which was located in patches throughout the habitat. Their local distribution was probably not related to the distribution of their major prey items. Shelter dependence appears to decrease with growth and fish switched from feeding on micro-crustaceans present in macro-algae to those associated with bare rock — coralline turf areas. Adults foraged throughout larger home ranges, but fed preferentially in microhabitats where their prey items (e.g. bivalves) were most abundant. (b) Juveniles tended to aggregate into loose foraging schools. This tendency declined with age and was associated with a corresponding increase in the rate of aggressive interactions among individuals of a cohort. Consequently, individuals of the same size became more spaced out as they grew. Between cohort association or aggression was rare and apparently unimportant in determining local patterns of distribution. Many interspecific foraging associations and aggressive interactions were recorded. However, with the probable exception of interspecific territoriality by the blenny Forsterygion varium, these behaviours probably had only a transitory influence on the distribution of the wrasse.