Creating wildlife habitat using artificial structures: a review of their efficacy and potential use in solar farms

The biodiversity crisis is exacerbated by a growing human population modifying nearly three-quarters of the Earth's land surface area for anthropogenic uses. Habitat loss and modification represent the largest threat to biodiversity and finding ways to offset species decline has been a significant undertaking for conservation. Landscape planning and conservation strategies can enhance habitat suitability for biodiversity in human-modified landscapes. Artificial habitat structures such as artificial reefs, nest boxes, chainsaw hollows, artificial burrows, and artificial hibernacula have all been successfully implemented to improve species survival in human-modified and fragmented landscapes. As the global shift towards renewable energy sources continues to rise, the development of photovoltaic systems is growing exponentially. Large-scale renewable projects, such as photovoltaic solar farms have large space requirements and thus have the potential to displace local wildlife. We discuss the feasibility of 'conservoltaic systems' - photovoltaic systems that incorporate elements tailored specifically to enhance wildlife habitat suitability and species conservation. Artificial habitat structures can potentially lessen the impacts of industrial development (e.g., photovoltaic solar farms) through strategic landscape planning and an understanding of local biodiversity requirements to facilitate recolonization.

Artificial refuges for wildlife conservation: what is the state of the science?

Artificial refuges are human-made structures that aim to create safe places for animals to breed, hibernate, or take shelter in lieu of natural refuges. Artificial refuges are used across the globe to mitigate the impacts of a variety of threats on wildlife, such as habitat loss and degradation. However, there is little understanding of the science underpinning artificial refuges, and what comprises best practice for artificial refuge design and implementation for wildlife conservation. We address this gap by undertaking a systematic review of the current state of artificial refuge research for the conservation of wildlife. We identified 224 studies of artificial refuges being implemented in the field to conserve wildlife species. The current literature on artificial refuges is dominated by studies of arboreal species, primarily birds and bats. Threatening processes addressed by artificial refuges were biological resource use (26%), invasive or problematic species (20%), and agriculture (15%), yet few studies examined artificial refuges specifically for threatened (Vulnerable, Endangered, or Critically Endangered) species (7%). Studies often reported the characteristics of artificial refuges (i.e. refuge size, construction materials; 87%) and surrounding vegetation (35%), but fewer studies measured the thermal properties of artificial refuges (18%), predator activity (17%), or food availability (3%). Almost all studies measured occupancy of the artificial refuges by target species (98%), and over half measured breeding activity (54%), whereas fewer included more detailed measures of fitness, such as breeding productivity (34%) or animal body condition (4%). Evaluating the benefits and impacts of artificial refuges requires sound experimental design, but only 39% of studies compared artificial refuges to experimental controls, and only 10% of studies used a before-after-control-impact (BACI) design. As a consequence, few studies of artificial refuges can determine their overall effect on individuals or populations. We outline a series of key steps in the design, implementation, and monitoring of artificial refuges that are required to avoid perverse outcomes and maximise the chances of achieving conservation objectives. This review highlights a clear need for increased rigour in studies of artificial refuges if they are to play an important role in wildlife conservation.

Patch use and site selection by a rock hyrax (Procavia capensis) in a human-dominated landscape in the West Bank of Palestine

Populations of rock hyraxes (Procavia capensis) increasingly occur in urbanizing areas of the Palestinian West Bank, and throughout the Middle East, in part due to construction methods that create rock piles that shelter hyraxes. We quantified activity densities of the hyraxes, environmental variables, and plant cover at four sites that differ in urbanization. The highest numbers occurred in the most urban site and peaked in June and October, with hyraxes traveling farther distances from their dens late in the season (October). Sites with higher activity densities of hyraxes had higher vapor pressures, signifying more mesic conditions. Thus, urbanization aids the expansion of hyraxes.

Shelter availability and human attitudes as drivers of rock hyrax (Procavia capensis) expansion along a rural-urban gradient

While anthropogenic land-use changes threaten wildlife globally, some species take advantage of such changes and disperse into urban areas. The wildlife in urban areas often promotes conflicts with humans, notably when the animals are associated with the spread of zoonotic diseases. In Israel, current urban invasion of rock hyraxes (Procavia capensis) draws public attention, since the species is a reservoir host of cutaneous leishmaniasis, a serious skin disease. The rock hyrax, however, has seldom been studied in densely populated areas, and the drivers for its urban expansion, as well as its abilities to live and spread in core urban areas, are relatively unknown. Here, we explore the rock hyrax expansion to urban areas process by examining the availability, characteristics and use of shelter along an urban gradient. Our findings suggest that a series of factors determines shelter availability and quality for the rock hyrax, which facilitates its dispersion across the urban gradient. We found that rock hyraxes from the Judean Desert expand to the peri-urban region of Jerusalem by colonizing new rocky shelters formed as by-products of urban development. With their populations reaching extreme densities in this area and saturating the available shelters, there is some spill over to the adjacent core urban areas where they colonize littered sites, which are made available due to the local socio-economic conditions and cultural norms of waste disposal and illegal placement of temporary structures. Our work emphasizes the significance of the urban gradient approach for studying the mechanisms promoting wildlife expansion to cities. Our findings suggest that changes in shelter availability and quality due to urban development, and cultural norms promote shifts of the hyrax population by pushing from the already established areas and pulling into new environment across the urban gradient.

Effects of land use type, spatial patterns and host presence on Leishmania tropica vectors activity

BACKGROUND

Leishmaniasis is a vector-borne disease, caused by the infection of Leishmania parasites which are transmitted by the bite of infected female phlebotomine sand flies. Leishmania tropica is transmitted by Phlebotomus sergenti and Phlebotomus arabicus while the main reservoir host is the rock hyrax. A marked increase in the incidence of cutaneous leishmaniasis (CL) caused by L. tropica has been detected in recent years in Israel; it is associated with infections which have emerged in new urban and rural foci. The objective of this study is to contribute to a better understanding of the preferred habitat, spatial activities and host-sand fly relationships of both species of vectors within various types of land use.

METHODS

Using CDC-type traps, we investigated the activity levels of sand flies. A field survey was conducted in 2016 at Elifelet, an agricultural village characterized by various types of land use. Movement patterns of P. sergenti between rock-piles were investigated by using colour-marked sugar baits and analyses of recapture patterns. In 2017, a survey was conducted in the hilly Jordan River area, by comparing sand flies and rock hyrax activities in relation to the size of rock-piles and vegetation cover.

RESULTS

Both sexes of both species were found to have a clear preference for rocky habitats over other land use types in rural landscapes. Movement patterns of P. sergenti were characterized by their high presence close to the rocks and an exponential decrease in their recapture, commensurate with the distance from the rocks. Host-sand fly relationships were found to have a higher correlation between rock hyrax activity levels for females than for males of both species of sand flies. Males exhibited the strongest association with the size of rock-piles.

CONCLUSIONS

The results suggest a strong affinity of both phlebotomine vector species to the rocky habitats of the Mediterranean areas. We suggest that rock-piles are associated with populations of rock hyraxes attracting female sand flies seeking blood sources. Rapid human population growth, coupled with intensive land-use changes and the creation of artificial rock-piles, which created potential habitats for both vectors and hosts in the proximity of many settlements, have increased the prevalence of L. tropica among the human population in the region.

Temperature effects on the activity of vectors for Leishmania tropica along rocky habitat gradients in the Eastern Mediterranean

Cutaneous leishmaniasis caused by Leishmania tropica, transmitted by Phlebotomus sergenti and Phlebotomus arabicus, has been detected in Israel. This research strives to identify the complexity of temperature effects on vectors of L. tropica and to analyze seasonality and distribution across altitudinal levels. Sand fly trappings were conducted monthly during 2015-2016 in an endemic region for L. tropica in the eastern Galilee. Trappings were conducted in hyrax den sites across a broad topographic and climatic gradient. Using N-mixture models, we investigated the activity levels of sand flies as related to temporary and periodic climatic variables. We tested generality of climate-driven models using Root-Mean-Square Error (RMSE) values by comparing the 2015-2016 data with trapping data from 2013. P. sergenti activity was found to be positively and exponentially correlated with early night temperatures and more strongly correlated with average early-night temperatures for two weeks. P. arabicus exhibited a linear correlation with temperature. Climate-driven models for both species yielded lower RMSE values for the 2013 data, which validate the generality of the models. Considerable differences were found in slope coefficients of temperature effect on sand fly activity among sites related to elevation levels, implying differential local responses of sand flies to temperature.

Borrelia persica infection in rock hyraxes

Tick-borne relapsing fever (TBRF) is an acute infectious disease caused by arthropod-borne spirochetes of the genus Borrelia and characterized by recurrent episodes of fever. Borrelia persica, the causative agent of this disease in Israel, is transmitted by the argasid tick Ornithodoros tholozani. There is little information about the maintenance and possible vertebrate reservoirs of B. persica in nature, but the tick O. tholozani is known to feed on animals that enter its habitat in caves, rock crevices and shady environments. The rock hyrax (Procavia capensis) is commonly found in such habitats and may therefore serve as a reservoir host for O. tholozani. Blood and spleen samples from rock hyraxes were collected from twelve locations in Israel and the West Bank during 2009-2014 to test if these animals may be infected with B. persica. Real-time PCR targeting a segment of the flagellin (flaB) gene was initially used to detect B. persica. Positive samples were further analyzed by PCR, using a segment of the glycerophosphodiester phosphodiesterase (GlpQ) gene for additional confirmation. Borrelia species were identified by nucleotide sequence analysis and the copy number of Borrelia was quantified in blood and spleen samples based on the number of Borrelia 16S rRNA gene copies. A total of 112 hyraxes were examined, with both blood and spleen samples tested from 108 animals. Nine hyraxes were infected with B. persica, with a prevalence of 8%. Of these, two animals were positive for both blood and spleen samples, three only for blood and four only for the spleen. The number of DNA copies of Borrelia 16S rRNA was significantly higher in blood (5 × 10⁶ to 9.2 × 10⁸/ml blood) compared to spleen (2.1 × 10⁴ to 1.0 × 10⁶/ml). We conclude that rock hyraxes are possible reservoirs for B. persica because they have long lifespans and gregarious habits, share habitats with vector ticks, and are naturally infected with this spirochete. Further studies should be conducted in the future to evaluate the competence of hyraxes as reservoirs for B. persica infection.

Landscape influences on dispersal behaviour: a theoretical model and empirical test using the fire salamander, Salamandra infraimmaculata

When populations reside within a heterogeneous landscape, isolation by distance may not be a good predictor of genetic divergence if dispersal behaviour and therefore gene flow depend on landscape features. Commonly used approaches linking landscape features to gene flow include the least cost path (LCP), random walk (RW), and isolation by resistance (IBR) models. However, none of these models is likely to be the most appropriate for all species and in all environments. We compared the performance of LCP, RW and IBR models of dispersal with the aid of simulations conducted on artificially generated landscapes. We also applied each model to empirical data on the landscape genetics of the endangered fire salamander, Salamandra infraimmaculata, in northern Israel, where conservation planning requires an understanding of the dispersal corridors. Our simulations demonstrate that wide dispersal corridors of the low-cost environment facilitate dispersal in the IBR model, but inhibit dispersal in the RW model. In our empirical study, IBR explained the genetic divergence better than the LCP and RW models (partial Mantel correlation 0.413 for IBR, compared to 0.212 for LCP, and 0.340 for RW). Overall dispersal cost in salamanders was also well predicted by landscape feature slope steepness (76%), and elevation (24%). We conclude that fire salamander dispersal is well characterised by IBR predictions. Together with our simulation findings, these results indicate that wide dispersal corridors facilitate, rather than hinder, salamander dispersal. Comparison of genetic data to dispersal model outputs can be a useful technique in inferring dispersal behaviour from population genetic data.