Effect of temperatures on sex determination, and yearly activity patterns, habitats preference and home range utilization

“Circle of life” of the species Testudo graeca in Israel: Effect of temperatures on sex determination, and yearly activity patterns, habitats preference and home range utilization
Mai Bernheim

Reptiles are one of the more susceptible groups to suffer from biodiversity loss as a result of human-induced changes in the environment, such as global climate change. There are solid evidences for the influence of global warming on species biology such as range-boundary changes and phenological shifts. Among reptiles there is a particular interest in the effects of climate change on species with temperature-dependent sex determination (TSD), where sex ratio is influenced by the temperature experienced by the eggs during the middle third of the incubation period. Therefore finding reptiles’ habitat preferences and how temperature affect hatchlings’ sex may provide vital information for managing their populations under climate change scenarios. Land tortoises are likely to be the most vulnerable to temperature changes, given their low dispersal capabilities, their occurrence in fragmented habitats and that most species are already threatened. The spur-thighed tortoise, Testudo graeca, is a terrestrial TSD tortoise with a circum-Mediterranean distribution. Courtship and mating season begins in March-April, but nesting occurs later between April and June, followed by 3 month incubation period. There is no data from natural environments in Israel on females nest habitats. Moreover, little data exists on adults’ seasonal activity patterns, home range and their micro-habitat preferences. The objectives of this study were to identify tortoises’ yearly activity pattern, home ranges, preferred micro-habitats and biotic conditions affecting the distribution of tortoises in Ramat Hanadiv; learn the effect of incubation temperature on sex determination of T. graeca in Israel, and the effect of nest location and temperature regimes on hatching success; and finally, to identify behavioral patterns of males and females in relation to righting behavior as a tool for sex identification. The research was conducted in two locations: Oranim academic college in Kiryat Tivon, where T. graeca eggs incubation experiments and hatchlings’ behavioral experiment were performed; Ramat Hanadiv Park, where I surveyed and marked 181 adults’ individuals and radio tagged 18 tortoises. MaxEnt models were performed for predicting distribution of individuals of T. graeca in the study area. The results show that between January and April both sexes exhibit maximum activity including courtship and copulations. Males precede females in decline of activity starting in May and lasting until October, while females decrease activity a month later. This study describes for the first time a long term summer-autumn activity hiatus of T. graeca in Israel. Models for predicting their distribution revealed that they prefer heterogeneous habitats that enable access to open and closed patches. Both sexes share same size of home ranges. There is an overlap among home ranges, and the tortoises do not show territoriality. Tortoises had a non-random occurrence on dark rendzina soil, where they were mostly found in shrub margins showing thermoregulatory activity, sleeping, resting, and mating. This particular micro-habitat probably provides them with relatively stable micro-climatic conditions. Sex determination of T. graeca in Israel follows the TSD mechanism, where incubation under constant temperatures above the pivotal point (a 1:1 sex ratio) during the thermo-sensitive period leads predominantly to females’ development and below this temperature predominantly to males. In natural nests temperatures fluctuate and can rise significantly above the pivotal temperature without affecting the embryos’ survival. It appears that females select carefully the specific nest location to ensure adequate incubation conditions. The effect of temperature fluctuations on sex determination in T. graeca is not known yet, mainly due to a lack of a reliable sex determination method to study hatchlings in the field. However, this study revealed the potential of using a behavioral method to distinguish between the sexes. While this study did not directly deal with the hazards of global warming on T. graeca in Israel, it shows the sensitivity of the sex determining mechanism to incubation temperatures, which should raise concern if global temperatures continue to rise.

Thesis submitted for MSc. Degree,  Haifa University
Under the supervision of Dr. Uri Shanas

Of further interest...

Accessibility

Physically Disabled in the Gardens

Many trails traverse the Memorial Gardens. We recommend this route, but you
can choose to walk another route.

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Sustainability

Sustainable Gardening

Gardening in the previous century was characterized by high-maintenance garden design, ostentatious use of plants and inanimate elements foreign to the environment, and overuse of non-environmentally friendly fertilizers and pest control agents

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Dining Here

Dining

To complete your Ramat Hanadiv experience, you are cordially invited to enjoy the culinary pleasures of Mata’im, the cafe-restaurant on our premises.

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Sustainable Gardening

Gardening in the previous century was characterized by high-maintenance garden design, ostentatious use of plants and inanimate elements foreign to the environment, and overuse of non-environmentally friendly fertilizers and pest control agents. While this approach produced immediate results, they came at the heavy price of environmental and groundwater pollution, diminished soil fertility, invasive vegetation, long work hours to control fast-growing plants, and routine use of mechanical equipment.

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במרכז המבקרים מתקיימים זה לצד זה גינון בצמחיית בר מובהקת וגינון בצמחי תרבות

With the increased global awareness of wastage and the environmental damage hidden in this approach, a contrasting trend arose to create sustainable interactions in ornamental gardens.

Sustainable gardening is defined as gardening that considers the needs of the current generation without harming the needs of future generations. It includes garden design that considers the existing elements on site – the landscape, soil, environment and vegetation suitable for the region. Sustainable gardening espouses a low level of maintenance and implementation of gardening methods that enrich the soil, increases the natural resistance of the vegetation to diseases and pests and avoid use of chemical fertilizers and control agents as much as possible.

The main aim of this kind of gardening is to reach a long-term balance between all components of the garden.

Ramat Hanadiv by number

The gates of Ramat Hanadiv are open to visitors 365 days a year (except Yom Kippur). The site is visited by over 500 thousand visitors per year, who enjoy the expanses of the Nature Park covering 450 hectares, the walking trails and the cycling trails. In the center of the Nature Park are the 7-hectare Memorial Gardens dedicated to the memory of Baron Rothschild and his wife. A connecting link between these two points of interest is the Visitors Pavilion, where a garden of wild plants and a garden of cultivated plants exist side by side.

Sustainable gardening is expressed in the Memorial Gardens, in the Visitors Pavilion and in the ‘Green Space’ in a number of ways:

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Maintaining landscape resources

The garden design of 1936 designated less than 50% of the garden areas to cultivated plants. The remainder of the land (about 4 hectares) remained adorned with local wild plants. As a result, during all four seasons of the year visitors can enjoy displays of native vegetation inside the gardens themselves.
During the dry summer, cultivated plants with a range of foliage colors (such as Acalypha and golden dewdrop) and interesting textures (such as cat’s tail asparagus) take center stage. The vast majority of the plants are perennials, and do not require intensive maintenance.
When constructing the Visitors Pavilion, great efforts were invested in preserving existing landscape assets, such as carob, pine and oak trees. The garden integrated pleasant-looking rocks, with their accompanying vegetation. Rocks that were dug out on site were crushed and integrated into the construction. On the building’s roof, soil mixed with crushed rock was spread out and enriched with locally-produced compost. In addition, through awareness and planning, the number of parking spaces for cars was reduced in order to plant many trees that will provide shade in the future to 80% of the parking lot area.

גינון בר קיימא, במערב הגנים
  • Water resource management

    The irrigation system in the Memorial Gardens was made more efficient using remote control. Likewise the amounts of water used to irrigate lawns and shrubs were reduced. The seasonal flowerbed area, a relatively high water consumer, was reduced to one percent of the garden area, and the freed-up area was filled with perennial vegetation with reduced water consumption.

    The garden of the Visitors Pavilion was planted with Israeli wild plants suited to the local climate, which after their establishment can be disconnected from the dripper lines and manage with the winter rains. An example of such plants are herbs and medicinal plants including rosemary, lavender, hyssop, oregano, fringed rue, tree wormwood, common sage, white micromeria and others; shrubs and trees such as European olive, Syrian maple, mastic tree, Palestine oak and Mount Tabor oak, sage-leaved rock rose and pink rock rose, wild grape, Judas tree and mock privet; and corms and bulbs such as Persian cyclamen.
    Diversion of marginal water (from air conditioners) and blackwater from the Visitors Pavilion to the biodisk purification plant. From the purification plant the clean water flows through purple dripper lines to a designated irrigation plot in the service area.
    In the Visitors Pavilion runoff water is drained into four drainage pits, penetrates the soil through penetration pits and is absorbed into the garden areas.
    The garden integrates ground cover with wood chips to maintain soil moisture and a pleasant temperature for the root systems, reduce reflected radiation, improve irrigation efficiency, prevent weed growth and enrich the soil as the wood chips slowly decompose.

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מיני בר נדירים מטופחים בשטחי המשתלה של רמת הנדיב במטרה להישתל בשטחים מתאימים ברחבי הפארק

Zero waste in the Garden

Garden waste leaving the Gardens or collected from the Nature Park is taken to Ramat Hanadiv’s composite site. There it is crushed, piled up into piles and decomposes slowly. Soil, rocks and tree trunks are kept on site, and are re-integrated as needed.

A Garden without poison

We minimize fertilizer and pest control with chemicals in the Gardens. Our approach is that a plant which is planted in the most suitable environmental conditions will reach its potential, be strong and not require special treatment. In the Memorial Gardens we do not use leaf blowers, and we implement follow-up and early monitoring of diseases and pests.

Integrating local vegetation

We established an Oncocyclus iris garden in the Memorial Gardens. The irises were collected from disturbed habitats around the country, acclimated and buried in the extensive areas (irrigated by rain alone, with no supplementary summer irrigation) in the Memorial Gardens. Conservation of rare wild species is also important to us; these plants are grown in Ramat Hanadiv’s nursery area, to be planted in suitable areas around the Park.

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A garden that attracts animals

Sustainable gardening supports local animals by creating a supportive habitat for them. An example of this is the Ecological Footprint Garden. This picturesque garden is based on vegetation that attracts butterflies, for nectar and as hosts. Butterflies are used as bio-indicators of the balance in their environment, and provide a glimpse of the biological diversity at their service. Such a garden also supports songbirds, for which the Garden’s tree branches provide defense, a place to nest and a food supply.

Positive interactions between humans and the environment

For over 50 years, the Gardens have been serving the broad public that comes for occasional visits, or to enjoy educational activities and cultural events, such as concerts in the shade of the trees and in the amphitheater. Another activity that contributes to strengthening the connection to the community is the work of volunteers from the nearby environment who work in the different divisions at Ramat Hanadiv. All this is done via consideration of the local plants and animals; we create a supportive habitat for them by limiting the active hours to daylight hours in order to free up the area for the animals during the night hours.

 

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In summary, the vision of Ramat Hanadiv, expressed through commitment to maintaining harmonious interactions between humans and nature, is reflected in the implementation of sustainable gardening throughout the Gardens, while sharing the knowledge accumulated in this field over many years with the professional and amateur public.

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Mata'im Restaurant
Kiosk
The Picnic Site

To complete your Ramat Hanadiv experience, you are cordially invited to enjoy the culinary pleasures of Mata’im, the cafe-restaurant on our premises. With an accent on absolutely fresh ingredients and healthful eating, Mata’im offers a top-quality (kosher) dairy  menu that brings diners to a new appreciation of the earth, of roots, and of the magnificent environment enveloping themselves and the restaurant.

Mata’im  is also proud of its social agenda: Part its staff is comprised of youth at risk, who are being trained for work in the restaurant business — paving their way to fruitful careers and successsful integration in society.

Mata’im — The Natural Place for Your Next Event

The restaurant is a relaxed and gracious venue for catered private celebrations and business events. Alongside Mata’im are meeting rooms and an auditorium equipped with the latest technology — the perfect site for seminars, staff meetings, training sessions, lectures and workshops.

Hours: 8 a.m.-4 p.m. ( See below opening hours during the holidays).

To reserve restaurant tables in advance (highly recommended) or plan an event, please ring us at:  04-8449998, or 050-4499590

e-mail: event@mataim.net